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juniperpublishersoceanography · 3 years ago

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A Comparison of Fish Kills in the Pamlico River and the Neuse River in Coastal North Carolina (A Symptom) and Abiotic Factors (The Root Causes)- Juniper Publishers

Abstract

For many decades the State of North Carolina (NC) witnessed fish kills in its coastal waters, particularly its inshore coastal estuarine and riverine waters. This study looks at fish kill data collected from two adjacent coastal rivers, the Neuse River and the Pamlico River, which both experienced fish kills over an 11 year period, and looks at possible naturally occurring abiotic environmental factors which may have contributed to or been responsible for the documented numbers of fish kill events and the sizes of those individual and collective events. In our study, naturally occurring abiotic environmental factors, including excessive precipitation or the lack thereof, and seasonal atmospheric wind fields, and subsequent estuarine circulations, were found to be responsible for creating strongly vertically salt stratified conditions in both river- estuaries, lowering dissolved oxygen levels in the bottom layers in the two separate rivers. We also present the possibility that excessive nutrient loading of both rivers may be responsible for lowering oxygen levels. These factors may have resulted in the fish kills.

Introduction

Fill kills are events which occur occasionally in NC coastal waters. The question is: why do these kills occur? In the early 1990's the occurrences received more public attention and political scrutiny because of the increased exposure of NC's dependence upon the use and health of coastal and estuarine waters for their livelihood, e.g. fishing, agriculture, and ecotourism, etc. and of visitors who come to the state for business and pleasure. During that period of time there was individual biological scientist who made the claim that the fish kills specific to the Neuse River were related to a previously unrecognized fish flesh eating organism, Pfiesteria piscicida is a dinoflagellate species of the genus Pfiesteria that some researchers claim is responsible for many harmful algal blooms in the 1980s and 1990s on the coasts of NC and Maryland [1]. Piscicida means «fish-killer» and was found in Neuse River waters. However, that claim was subsequently challenged by other scientists claiming that the findings were flawed [2] and other environmental factors likely contributed to the fish kills; with the vampire organism attacking the dead fish after the fact. That scenario would be analogous to the role of Turkey Vultures on land. This dinoflagellate may have been a carnivore but was not a killer. Proof of what actually occurred in the Neuse River was never scientifically documented; specifically that the purported flesh eating organism was responsible for the reported fish kills. Moreover the Pamlico River, which is adjacent to and north of the Neuse River was never part of the public and or scientific community fish kill discussion at the time, and may have never been biologically sampled. We do not know if it was or was not. What we have been able to accomplish is to acquire the files of fish kills over an 11 year period of time from both the Neuse and Pamlico Rivers, via a NC state agency, and to compare the numbers of events, the size of the events and possible causes of the fish kill events.

We revisit and readdress the question surrounding the likely cause of the fish kills via the study of fish kill data obtained from both the Neuse River and the Pamlico River systems, adjacent coastal rivers in NC, along with other abiotic factor, environmental data. Fish data was obtained for an 11-year period for the 11 year period, 1985 to 1995, was examined.

Data and Methodology

Figure 1 and Figure 2 provide a composite of the geographic locations of the two lower river-estuarine basins and the cumulative fish kill data. The lower Pamlico River extends from its nominal head at Washington NC down to its mouth and empties into western Pamlico Sound and is to the north of the Neuse River. The Neuse extends from its head at New Bern NC down to its mouth into western Pamlico Sound. Both the Pamlico and Neuse Rivers function as shallow coastal plain estuaries [3,4]. The Pamlico River is relatively straight from its head to its mouth. The Neuse River has an abrupt crook or bend in it at Minnesott Beach. The nominal heads of both river-estuaries are located at approximately the upstream extent of salt water, which derives initially from the adjacent Atlantic Ocean, is advected through the Ocracoke, Hatteras and Oregon Inlets (Figure 1) and then is advected in the bottom waters across Pamlico Sound to the mouths of the two rivers [4].

Serendipitously we discovered that the NC Department of Environment and Natural Resources -Division of Marine Fisheries (DENR-DMF) possessed 11 years of fish kill data from the adjacent rivers. We decided to collect all of these data, as could be made available, from the regional and main offices of this state agency DENR-DMF regional offices were contacted and their records concerning fish kills in the geographic areas of interest were requested. At the convenience of the staff located at the regional offices, an NCSU student representative visited and made copies of the files. The files were examined, and the fish kill data was then incorporated into a spreadsheet according to location, date and estimated size of kill, as reported. Environmental factor data were obtained from the National Oceanic & Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI).

Of particular importance to the collection of the fish kill data were the DENR-DMF Raleigh Office and the Washington (NC) Regional Office. The Raleigh Office is the main office of DENR-DMF, and serves as the central repository for all of the data collected at the regional offices. Regional offices send the information regionally gathered to Raleigh where it is centralized. NCSU representatives examined the files and made copies of documents that were not found in the regional offices. This process allowed for a check and balance on the data sets. However, the process revealed that occasionally regional office data sets and main office data sets differed. Every effort was made by the NCSU representatives and DENR-DMF staff to ensure the correctness and completeness of all data sets.

The fish kill data sets were then compiled into spreadsheets and are provided as a collective overview in both a time-series format as well as in a schematic form (refer to Figures 2-5). All of the annual time series, schematics and data summaries can be provided by the first author of this manuscript. Within the text, the data are summarized and described in terms of the time series as well as in geographic context. In both plotted and contoured forms, the data reveal the frequency and extent of fish kills and should be used as a diagnostic tool. The intent of the study was to examine the fish kills over the 11 year period in the two adjacent coastal river estuaries for their relative experience of fish kills and to determine if there were associated environmental factors that could have played a role in the frequency of occurrence and size of the events. The number of events, as well as size of event recorded, are presented for an 11-year period and assumed to be sufficiently representative. The point of the comparison is dual in purpose; firstly, to probe the health of NC's estuaries in terms of a possible invasion by an alien virus; and secondly to determine if naturally occurring factors or anthropogenic factors could have contributed to the documented fish kills.

Overview and Results

In viewing the 11 years of fish kill data on a year to year basis (Figure 3), the fish kills appeared to have peaked in the late 1980's and then diminished in later years into the middle 1990’s. One likely explanation for the apparent increase in kills in the 1985-1990 time period is the fact that the Pamlico Sound System Emergency Response Team (PERT) was active over this period of time (June 1988-March 1990) but not so active thereafter according to DENR- DMF personnel reports. PERT responded to all kills reported to it. From discussions with DENR-DMF personnel, it appears that in the years following the more active earlier PERT period, less emphasis was given to going into the field to investigate reports of fish kills. So while there may have been comparable number of kills in earlier and later years, fewer kills may have been reported or investigated. There were also a significant number of reports that did not have a count or estimate of the numbers of fish killed. In fact, there were more fish kills in this "no estimate" class than in any other. It is of note that the plotted and geographically configured data (Figures 2-5) presented do not include any fish kills which were the direct and immediate result of a slug of waste or some other contaminant being dumped directly on a patch of fish as a small, localized toxic point source. The measurements of water conditions all come from the deepest part of the river examined at each incident. Extensive kills were located on the maps in the centers. Any other data not known to the authors of this report can easily be folded into this data set, upon discovery and confirmation.

During the period of 1985-1995, the lower Neuse River received a great deal of public, government and private industry attention and scrutiny; particularly in newspaper and news media reports. In fact the news caused a hue and cry for solutions from the NC State Legislature and the previous "NC Department of Environment, Health and Natural Resources (DEHNR)" underwent a name change whereby "Health" was dropped. Alternatively, news reports of fish kill events in the lower Pamlico River were essentially non-existent during this period of time. However, the DENR-DMF records reveal that a significant number of fish kills were realized in both lower river basin. In fact there were more which occurred in the Pamlico River. This came as quite a surprise to the authors of this study.

Figure 2 shows the cumulative 11 year data by specific geographic location and magnitude of event. Figure 3 presents an overview of the frequency of occurrence, i.e. the total numbers of reported events, over the 1985-1995 period of time on a year by year and event-size basis. Figure 4 is the cumulative summary over the 11 period by river. Figure 5 is a representative composite of fish kills by event and size for the year 1989 which was the peak year for both rivers; as shown in Figure 2. In the representative Figure 5, number of kills for each river is provided for small (<100), medium (100≤<1000) and large (>1000) are provided. The schematic displays the "kill level" data and geographic location along with the number of occurrences over six different levels (including "no estimates") of fish kills. However, in Figures 2-5 only 319 of the 399 presumed events were considered because of questions regarding 80 of the reports.

Based on the DENR-DMF data sets as representatively shown Figures 2-5, our preliminary summary is:

1. The Pamlico River experienced a higher rate of fish kills of all sizes, than did the Neuse River, in 10 of the 11 years (19851994) of this study, with the exception being 1995.

2. The total number of DENR-DMF reported fish kills in the Pamlico River was 246 over the period 1985-1995, or 22-23 per year.

3. The total number of DENR-DMF reported fish kills in the Neuse River was 73 over the period 1985-1995, or 6-7 per year.

4. The Pamlico River experienced approximately 77% of the total number of fish kills reported for the Pamlico and Neuse Rivers over the period (1985-1995), with the Neuse experiencing 23% of the total;

5. The Pamlico River had a higher rate of incidence of Level 2 sized (<100) fish kills, than did the Neuse for 9 (1985-1992, 1994) of the 11 years, except for 1993, with 1995 a null year.

6. The Pamlico River had a higher rate of incidence of medium, Level 3, sized (100≤ <1000) fish kills for eight of the 11 years (1985-1992, 1994) an equivalent rate for two of the years (1989, 1993) and below in one (1995) than the Neuse River.

7. The Tar-Pamlico River had a higher rate of large, Level 4 (1000 <1,000,000) and the largest Level 5 (>1,000,000) 8 (1985-1988, 1990-1991, 1993-1994) of the 11 years, an equivalent rate in 1992 and a smaller rate in two (1989, 1995) of the 11 years, than did the Neuse River experience.

8. Fish kills in the Neuse River were distributed heterogeneously being concentrated in three principal areas, one on the south bank upstream of Cherry Point NC, near New Bern NC and the other on the north bank between Arapaho NC and Janeiro NC with a hot spot focus at Minnesott Beach NC.

9. Events in which no estimates of the numbers of fish killed outnumbered all other sized events. Further, in 10 of the 11 years (1985-1994), the Pamlico River recorded as many or more "no estimate" events than did the Neuse. The exception was 1995.

10. Fish kills in the Pamlico River are spread throughout the system in a more homogeneous fashion then they were in the Neuse River.

11. Fish kills were not prevalent in the lowest regions of either river, in the areas where the rivers connect to Pamlico Sound.

The lower Pamlico River has all of the attributes of a "coastal plain estuary" [4] and as such has 3 modes of circulation:

a. A top to bottom fresh-water discharge mode, where flow is outward from surface to bottom.

b. A 2-vertical layer fresh-water downstream surface layer and an upstream directed salt water bottom layer and

c. An upstream directed salt water storage mode.

The Pamlico River circulation does not favor either the right or left bank of the river. Alternatively, the lower Neuse River has all of the modes of the Pamlico River but also has a cross-channel flow at the elbow-crick, in the vicinity of Minnesott Beach. The cross channel flow is from the north to the south bank at the surface and from the south to the north bank along the bottom [4]. This pattern tends to concentrate fresher waters on the south bank and saltier water on the north bank.

In a pioneering study, Taylor et al. [5] showed that seasonal winds and the amount of precipitation played a major role in the outcome of Year Class Strength of estuarine dependent finfish (Figure 6). In that study, it was demonstrated that the numbers of juvenile and one to two year old, estuarine dependent finfish that were present in juvenile nurseries in the Neuse and Pamlico Rivers rise during the periods of February through April when winds blowing from the southeast are more persistent (Figure 7a). These winds drive waters that originally came from the adjacent Atlantic Ocean into Pamlico Sound via Ocracoke, Hatteras and Oregon Inlets drive by northeast (Figure 7b) are present. The shelf waters are more saline than the sound waters and thus sink, flowing in a bottom boundary layer into the lower reaches of the two river mouths. Then, with a sufficient amount of spring precipitation, the freshwater flows downstream in a surface layer creating a two- layered circulation.

This 2-layered vertical circulation is prevalent throughout the Pamlico River up to the head. In the Neuse River this 2-layered flow also exists but at Minnesott Beach, the elbow creates a cross-channel flow towards the south bank at the surface and a flow towards the north bank along the bottom. In both riverine situations, the systems become strongly vertically stratified, cutting off the supply of oxygen to the bottom layer. Oxygen enters the water columns at the surface interface with the atmosphere and is mixed downward. But, if winds come out of the southeast and bring in salt water to the mouths of the rivers, and then winds blow out of the northwest thereby accelerating freshwater flows downstream in the surface layer, then the vertical integral of the longitudinal density gradient will advect more salt water into system, further strengthening the 2-layered system. Of course this salty bottom layer is also the locale of the ingression of estuarine dependent finfish and it extends into the small tributaries located along the banks of both rivers. What sort of wind event would cause such a transition from Southeasterly (Northwestward) winds followed several days later by Northwesterly (Southeastward) winds?

The answer to the question posed above is: "An Extra-Tropical or Mid-Latitude or Cape Hatteras Low Cyclone". Are these Atmospheric Cyclones prevalent in the vicinity of Pamlico Sound? The short answer is "Yes". In fact 54% of all U.S. Atlantic Seaboard Extra-Tropical Cyclone (ETC) winter storms are spawned from South Carolina to Virginia, centered about Cape Hatteras NC [6]. The structure of an ETC is shown in Figure 8. The numbers of ETCs over a period encompassing the fish kill data are presented in Figure 9. As shown, 1988, 1989 and 1990 were relatively stormy years. 1993-1995 were much less stormy years and the numbers of fish kills also dropped significantly (Figure 3).

We see in Figure 9 above that over the 57 year period, 19502006, there were between 1 and 12 ETC's per year that were present in the vicinity of the Pamlico Sound system. 1985 was a relatively quiet year with 2, but years 1988, 1989 and 1990 were busy years with 8, 9 and 7 events per year, respectively. The numbers of fish kill events (Figure 2) were approximately 50, 110 and 40 over those years, respectively, decreasing thereafter, in sync with a decrease in the number of ETC storms.

In Figure 10, the three-dimensional numerical model system that was used in Pietrafesa et al. [4] and again in Xie & Pietrafesa [7] was employed to produce the output of the surface and bottom salinities in the Pamlico-Albemarle-Croatan Sound System following the passage of an ETC over the period April 16-19, 2001. The model output clearly depicts the bottom salt water layer below the relatively fresher water surface layer. This is characteristic of a two layer, salt stratified coastal plain estuary [3].

A protocol for estuarine health - fish kills as a symptom

Fish kill events in the Tar-Pamlico and Neuse Rivers and presumably other parts of NC’s estuaries are frustrating for three reasons:

a. They occur in estuarine dependent finfish recruitment and growth periods which flies in the face of the entire abiotic abetted and aided recruitment process;

b. They reveal a lack of understanding of the underlying causes for the kills and

c. They point to an inadequacy or inability to solve problems related to the health of at least two NC river - estuaries.

In truth, fish kills are commonplace in estuaries. However, frequent kills, particularly those of significant size, are symptoms of an unhealthy environment, and NC's estuaries are no exception. Thus any effort to either understand or reduce kills must be multi-faceted. A comprehensive approach to understanding the causes will position present day managers to deal with other, even unforeseen, problems. So here we suggest solutions that will help us deal with other problems as well. An important benefit will come in the future when tough management decisions will be required to restore the health of our estuaries. A scientifically credible basis for these decisions can be provided. In doing so, we make the decisions defensible.

The questions surrounding fish kills are the same as when a human patient dies. What was the cause of death? But the more important question is: what made the patient vulnerable to the cause of death? We must resist the temptation to treat only the symptoms. Fish kills are known to be related to disease, toxins, suffocation, starvation, and other causes. Typically, in the past and to the present, most of the attention has been paid to diseases. However, these diseases are now known to be common in many parts of Pamlico Sound and other NC estuaries as well. So the important question is what conditions cause disease to become virulent? We must consider disease a symptom of a more general environmental deterioration. In fact, there is evidence that Pamlico Sound has become increasingly prone to low oxygen levels owing to nutrient loading, and low oxygen may contribute to the conditions that cause disease to become a problem, but the situation is likely more complex. It will require more than a prescription to restore our estuaries to health. The good news is if we adopt a strategic, rather than a tactical approach to the problem of fish kills, we can position ourselves to understand and prevent other problems before they arise.

The components of a comprehensive program to understand fish kills, as well as to insure the long-term health of our estuaries, must include changes in both research and management. The research community must become more involved and management must be professionalized to a level never before required. New research input from the universities, increased number of fisheries and water quality professionals, and increased local involvement are all required components of a comprehensive plan.

This study constitutes a step in addressing the fish kill problem by pulling together data and information from different sources, both biotic and abiotic. Data on fish kills exist as a result of DENR-DMF investigations, have apparently never been analyzed, integrated, or synthesized. For example, one issue which could and should be addressed is: what fish of what size were killed in relation to fish present at kill sites? The Taylor et al. [5] study of Year Class Recruitments of Estuarine Dependent Finfish includes a Cluster Analysis that selected recruits by species and size. With such information, one could begin to hypothesize about causes, and design investigations to follow such leads. Along with summaries of what we know about the hydrodynamics, the distribution of toxins, particularly oxygen-demanding nutrients, as well as other inputs to our estuaries, one could begin to design a research program to support estuarine management decisions. But these data must be linked from the outset. Most studies of estuaries do not link biological, chemical, geological and physical components. This is a failing which in study design.

For example, hydrodynamics and water quality data collection should be linked to what we know about the physiological and behavioral responses of fish to variations in water conditions. We know low levels of dissolved oxygen typically occur just before dawn, yet we rarely collect data at that time. Knowing the oxygen at noon, or the average oxygen concentration over a month or week or day or even hour is not adequate. Fish suffocate in a few minutes with insufficient oxygen, so we need to monitor oxygen. Also, the supply of land based nutrients used as fertilizers on the farms upstream from and along both rivers has likely been increasing over time and those nutrients fuel biological productivity thus pulling O2 out of the water column leading to toxic algal blooms. To our knowledge temporal and spatial time series of nutrient fluxes have not been conducted system-wide. In summary, we need to summarize and analyze the data we already have, identify data gaps, and proceed to systematically collect needed data. There are federal and state agency field programs across the coastal landscape nationally but few if any have ever been comprehensive in design and execution. Which is why presently we know so little about the functioning our precious estuaries, locally, regionally and nationally.

Although many of the elements are already in place, the infrastructure to link them needs to be improved. Not the least of the necessary changes is to allow the agencies with the responsibility of improving the scientific basis for management the freedom to manage professionally with minimal political interference. This has never been done. The future will be managing inputs and outputs with a scientifically-defensible management plan. However, there is a built-in conflict of interest in charging the scientific and monitoring requirements to improving the knowledge base necessary within the same agency which has a regulatory mission. Here the academic community can be of great service. Universities have much of the critical scientific and technical expertise, but a new infrastructure is needed to make best use of state resources (including universities and staff agencies), through participation in a professionally-crafted management strategy.

Like human health, fisheries depend upon a healthy environment. A healthy estuary for fish has minimal constraints on productive capacity and minimal maintenance costs. The difference between capacity and maintenance costs defines both health and resistance to stress. In a fish kill, either the capacity is lowered or the maintenance costs are raised to the point where resistance is zero. For example, sub-optimal salinity or high temperature raises the maintenance costs for a fish, low oxygen constrains capacity. When oxygen levels fall below that necessary to meet maintenance costs, the fish dies. But before resistance to stress falls to this level, fish are vulnerable to diseases. This more ecological view of health is precisely what is needed for estuaries, but it will require some new information and a new perspective of our estuaries' health. For fisheries and fish kills, there are three main research needs.

i. First, we need to know the distributions of water quality factors.

ii. Second, we need a better understanding of effects of water quality on fish health.

iii. Third, we need to know the impacts of these effects at the population level, i.e., how they must be integrated with traditional management.

Conclusion

The frequency of occurrence and size of fish kills which have been documented over the 11-year period 1985-1995 in two geographically adjacent NC coastal plain riverine estuaries, the lower Neuse River and the lower Tar-Pamlico River, both of which are connected to Pamlico Sound, are presented. While conditions deleterious to the health of fish in the Neuse River have historically received much attention, much less has been heard concerning the health of the Pamlico River. However, DENR-DMF records reveal that of 319 fish kill events reported over the 11 year period, 77% of those occurred in the lower Pamlico River versus 23% in the lower Neuse River. Additionally, kills in the Neuse were concentrated in three more or less distinct areas suggesting localized hot spots while those in the Pamlico were distributed more evenly. This may be a complex function of a coupling of the hydrodynamics to biogeochemical processes and the water quality of the estuarine system. These issues are addressed in this study but, in truth, will remain speculative, problematic and unresolved until a thorough, coordinated, comprehensive field and modeling effort is mounted.

The problem encountered during data collection at the various offices of the DENR-DMF was that the staff in charge of the fish kill data were not always aware of where all the data was located. The main office in Raleigh was supposed to have all of the data that could be found in Washington (NC), but this was not the case. For example, NCSU representatives working with DENR-DMF staff found data in the Raleigh records that were not in the Washington office, and also found data in the Washington office that were not included in the Raleigh records. Some of the reports appeared to have been entered into a computer system. However, none of the staff who were asked about this had any idea of the location of the computer files or if they even existed.

It is time for a new era of fisheries management with significantly improved environmental input, significantly improved data handling, and significantly more input from our universities. Given an improved infrastructure and a high level of trust and cooperation, the management strategy necessary to restore and insure the long-term health and productivity of our estuaries can be crafted and implemented.

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juniperpublisher-ph · 5 years ago

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Typhoid Fever, a Public Health Problem in Hospitals : Case Study at a Work station in Kinshasa, DR Congo-Juniper Publishers

Juniper Publishers- Juniper Online Journal of Public Health

Abstract

This study focuses on typhoid fever in its public health aspect. It is a driving force in admissions to hospital. It affects more adults who are part of the staff of health establishments in Kinshasa in the DRC. Our clinical picture was dominated by headache (25%), fever, insomnia and cough (12.5%), asthenia, abdominal pain (8.4%), and the dissociation of Pulse and temperature, vomiting and hypertension (4.2%). Our study shows that workers assigned to collection-sorting until disposal of care waste are sick of typhoid on their workstation.

Keywords: Typhoid fever; public health; Case study; Kinshasa (DRC)

Introduction

Human health has several factors that cause its evolution to be linked to several factors such as physiological, moral, armed conflict, expansion of several diseases and degradation of the family environment in society. Migration, displacement of populations especially in developing countries are factors that underlie various diseases. These diseases worry physician researchers and their work teams. Typhoid fever is common in several countries of the world and is common in countries with low levels of hygiene. It is endemic and poses a significant public health problem. According to statistics, there are 21,000,000 cases per year and 200,000 deaths worldwide [1]. In developing countries, the incidence is 540 cases per 100,000 or 0.2 cases / 100,000 in temperate countries [2]. In high-income countries, typhoid fever is contracted while traveling abroad. It quickly eradicates because the living conditions are better and the health system is also better. Moreover, given its climatic conditions, the living standards of the inhabitants and other endogenous factors, Africa is not immune to the spread of typhoid fever.

Man is the only reservoir of viruses because contamination is by water, food because in the most affected areas children, adolescents and even adults are the first carriers of this virus. Since the 1990s, the incidence of antibiotic-resistant Salmonella typhi has increased rapidly in the Indian continent, South Asia, sub-Saharan Africa [3]. Man is then the chronic carrier and plays an important role in the transmission of the disease. He may lodge it and excrete it in the stool. So we call it a disease of the hands rooms. The literature shows us that this disease is a public health problem but we do not have national statistics in DR Congo. This pathology is endemic [4].

For example, Mr PARENT studied typhoid fever in Lubumbashi (eastern DRC). In Kinshasa in 1977, Omanga conducted a study in children. In 2008, an epidemiological study of adult typhoid fever in the city of Goma in eastern DRC on 57 cases from January to December 2008 [5]. The bacteriological and epidemiological aspects of salmonellosis were observed at the University Clinics of Kinshasa (CUK) in 1968 by Gatti [6].

Some Concepts

Salmonella are enterobacteria that do not ferment lactose and aid in the non-production of urease. They are parasites of man, rodents, poultry and reptiles. As a result of oral penetration, salmonella (single-cell species) are the basis of typhoid fever, gastroenteritis and Food-borne infections. Typhoid fever is a bacterial infection caused by Salmonella enteria serotypes Typhi and Paratyphi (A, B, C). It is a mesenteric lymphoma starting point and is caused by four antigenically distinct human Salmonella servers but of similar pathogenicity These Salmonella are called major because of the seriousness of the pathology they cause.

From the point of view of Pathophysiology and biological diagnosis, Salmonella are integrated with a contaminated drink or food. The infective dose would be 105 bacteria. They are evidenced by haemoculture and / or by coproculture, and / or by demonstration of specific antibodies by indirect diagnosis. The serodiagnosis of WIDAL and FELIX detects the presence in the blood of antibodies directed against the constituents of Salmonella [7]. As for preventive treatment, it is based on general hygiene and TAB vaccination of specially exposed populations such as military personnel and hospital staff. From a curative point of view, treatment is based on antibiotic therapy (use of chloramphenicol followed by fluoroquinolones and cotrimoxazole) [8].

Public health is a study of the physical, socio-cultural and psychosocial determinants of population health and actions to improve the health of the population [9]. Other authors define public health as a science and the art of preventing disease, prolonging life and promoting health. The ultimate objective is to enable each individual to enjoy his or her innate right to health and longevity [10,11]. Unlike medicine, public health rests on two levels; On the one hand, it emphasizes prevention rather than curative treatment and on the other hand it develops a population approach [12].

Case study in this article concerns the workers and not the nurses of the four hospital structures in Kinshasa (CUK, Kinshasa University Clinics, HGRK, Kinshasa General Reference Hospital, HGK, Kintambo General Hospital and HGRN, Reference of Ndjili or Sino-Congolese hospital) in DRC ongo allocated to the management of hospital waste. As a result of our observations, we define hospital waste as a collection of household waste (DAOM) and infectious-care waste (DASRI) as shown in the attached photos. Our primary objective is to review the clinical signs associated with typhoid fever on this target population. One way to make an inventory during a fixed period of the presence of this disease of the hands rooms in this workstation. Far from us to see, the epidemiological aspects, but we will insist on the prevention of the diseases associated with typhoid fever.

Materiel and Method

This study of prospecting and research-action concerns 80 suspected cases of typhoid fever following various clinical signs observed in the exercise of their function in 2006. These are the general signs (fever, asthenia, dissociation of the pulse and temperature); Digestive signs (abdominal pain, diarrhea,vomiting); Neurological signs (headache, dizziness, insomnia); Respiratory signs (cough, Ronchi) and other signs such as high blood pressure and angina (Figure 1)

Case follow-up began in 2008. The dossier must meet the following criteria:

Be between 30 and more (often the men are assigned to this work door)

Present the general, digestive, neurological, respiratory and other signs mentioned above

Find in the stools, urine, blood, cerebrospinal fluid the seed sought.

A total of 272 workers or interviewers (141 at the CUK, 69 at the HGRK, 35 at the HGRN and 27 at the HGK) are assigned to this position. We chose 20 per hospital, so we have a sample of 80 cases to follow. These cases were not chosen at random but more for their regularity at work and sometimes their seniority of the 80 agents, clinical signs were observed during the study, of 24 of them, 30% of the cases. Thus the 24 workers were followed and hospitalized in internal medicine of each place of work.

The elements related to our surveys show, when we observe the photographs, that there is a failure in hospital hygiene, individual and collective. Indeed, workers collect waste that is not sorted without protection. With their hands, they accompany the waste to their place of treatment. As the incinerator no longer works, the waste is put in a National Program, sanitation bin where they are burnt. This behavior is dangerous for the environment (pollution of the air, fauna and flora (Figure 2).

Mode of Contamination

The method of contamination in the 24 cases of 80 workers in our sample was indirect. On the other hand, the probability of direct contamination comes from the workplace. The clinical signs observed during the 2006 campaign Table 1 shows that the clinical signs of typhoid fever occur on 30% (24/80) of workers assigned to the collection and treatment of hospital waste in the healthcare setting. Some workers have a picture suggestive of typhoid fever others have been for a fever that has resisted against quinine, chloroquine, artemisin, and to antibiotic therapy. The length of time between the onset of the illness and the day on which we requested hospitalization was long of the 24 cases, 17 cases or 70.85% accepted their hospitalization in February 2007. Admission was motivated by the isolation of germs in the stools of workers complaining of digestive disorders. In a few cases the symptomatology was not suggestive of typhoid fever.

The microbiological diagnosis was selected on the basis of blood cultures, coprocultures, urocultures and biliculture. Thus, 15 haemocultures were performed in 17 patients, 16 positive coprocultures. S. typhi was isolated from 11 urocultures (only one allowed). It was demonstrated in the 17 patients. Associated conditions not mentioned here, such as intestinal parasitic infections, hookworm infection, amoebiasis, anguillulose have not been studied. Urinary tract infections have been associated with typhoid fever. The patients were treated with chloramphenicol monotherapy at 25gr. Antibiotics were administered as a combination. The average duration was 14 days. Progressive treatments were applied (Table 2).

Discussion

Worldwide annual estimates of typhoid are 17 million according to the WHO [13]. In our study of the sample of 80 staff members divided by 20 in four hospitals, there was an improvement on 12 of the workers for the 17 with recognized symptoms of typhoid. This study did not allow us to classify the epidemic as seasonal. However, the disease is linked to a defective hygiene and the predominance is masculine because in the collection of waste and discarded, it is the men who are affected. The statistical study of the clinical symptoms compared according to the authors on 208 cases, we also demonstrate the persistence of the same symptoms to date. Fever took the lead with 89.9% of the 208 cases studied [4].

In this case, typhoid fever is predominantly an adult disease and urban origin predominates. The mode of direct contamination illustrates the fact that paramedical personnel (workers) are affected. Fever that does not respond to antimalarials or antibiotics is a reason for hospitalization as well as permanent headaches. Improved indicators of typhoid for 70.85% of patients or sufferers is effective. Patients are advised to wash their hands after each treatment. Similarly at home, they should take boiled water disinfected if possible with chloramines. Public health interventions to prevent typhoid require that health education be emphasized in terms of worker hygiene (hand washing at work, during meals, etc.), sanitation systems (Such as appropriate gloves, boots, overalls, glasses, etc.), to ensure that appropriate clothing is used in the handling of hospital waste.

Conclusion

This study is a development of this condition within healthcare institutions as regards the management of hospital waste. Measures to combat typhoid in hospitals include education and awareness in a healthy way of treating hospital waste from collection, sorting through treatment. It is recommended the use of appropriate treatments, antibiotics or vaccine use (does not provide definitive protection) available to those who work or are exposed to high-risk areas. Let us also not forget that the DRC is in Africa, which is an area at risk where the population is confronted with the highest burden

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annieboltonworld · 3 years ago

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Juniper Publishers-Open Access Journal of Environmental Sciences & Natural Resources

A Study on Sthalavrikshas in Temples of Madurai District, Tamil Nadu

Authored by Vinoth Kumar A

Abstract

India delivers rich biodiversity and it is not just the world’s twelve mega diverse countries, but also one of the eight major centers of origin and diversification of domesticated taxa. These taxa are conserved and have been considered sacred because of their cultural, religious and economic importance. In Tamil Nadu, some sacred trees are in the status of extinct, endangered, threatened, and vulnerable and vary rare habit. The sacred trees are very good examples of ex situ conservation, where a single plant is conserved and worshipped. A study of Sthalavrikshas is also known as sacred trees (or) temple trees was conducted in the temples of the Madurai district during 2016-2017. The study revealed the presence of Sthalavrikshas in 65 temples out of 100 temples studied. Totally 31 species of Sthalavriksha recorded in these 65 temples.

Keywords:Biodiversity; Conservation; Sthalavrikshas

Introduction

Sacred groves and sthalavriksha (temple tree) have been acting as a major role in the conservation of plants and animals. In the location are certain ethnic groups and residential district in India, which have been worshiping forests, trees and certain animals since time immemorial. Occurrence of sacred groves at several spaces in India, clearly defines the community’s attachment to nature. Sacred plants play a really significant role in ecology. Due to their ecological value and effective properties, sacred plants continue to be employed in the religious and social festivals of the Hindus. The five most sacred leaves of pipal, Cluster fig, white fig, banyan and mango are ubiquitously employed in making prayers and oblations. On auspicious occasions, mango leaves are attached to train and strung up on doors as a welcome banner, and leaves of purasu and banyan make workable plates and bowls during community feasts. Leaves of some other trees are also customarily offered to deities e.g., Vilvam (Bengal quince) to Lord Siva, of banana and Arjuna to Lord Ganesha, and of kontrai (Cassia fistula) to all the gods and goddesses. The red flowers of the Indian coral tree are used in the worship of Lord Vishnu and Lord Siva; of Alari (Nerium indicum) in the worship of Lord Siva and the Sun-god; of ketaki (Yucca gloriosa) in the worship of Lakshmi, and of pala or breadfruit (Artocarpus integrifolia) in the worship of Lord Vishnu. The purpose of some flowers is prohibited in worship rites like vaagai (sirisa or parrot tree/Albizia lebbeck) in the worship of Lord Ganesha and vengai (Pterocarpus marsupium) in the worship of Lord Siva. The wood of the sacred trees like vilvam, banyan, vanni, purasu and pipal is never employed as fuel, as it is believed to invite the anger of gods. But it is employed in other ways, in sacrificial rites and ceremonies. Sudhakar [1]. Sthalavriksha worship in temples is a popular exercise. Most of these temples have their own Sthalavrikshas (temple trees) and Nanthavanam (flower garden). Sacred plants provide food, shelter and nesting substratum for several species of birds and squirrels. All souls of certain species are completely protected. Sthalavriksha is a natural tree found in the temple site before construction of the temple and most temple myths (Sthalapuranas) and temple histories (Sthalavaralaru) refer to a prime deity that was first unearthed or found under the tree Gunasekaran & Balasubramanian [2]. Every temple has one plant or tree as sthalavriksham. Sthalavriksha means the tree of the locality (sthal-place; vriksha-tree). In Tamilnadu state, about sacred trees are in the status of extinct, endangered, threatened, and vulnerable and vary rare habit. Such trees are both ethno botanically or culturally important and ecological representative of the area.

Sthalavriksha or temple tree is a single plant worshipped as equal as the prime deity in the temples. In both Hinduism and Buddhism, temple tree worship holds a bigger significance. The plant, primarily worshipped are Peepal (Ficus religiosa), Neem (Azardirachta indica), Bael (Aegle marmelos), Sandalwood (Santlum album), etc. There are temples which have more than one Sthalavriksham simultaneously, whereas some temples like a Sri Kallalagar temple (Prosopis cineraria (L.) Druce and (Pterocarpus santalinus L.f.) to have different Sthalavriksham is different yugas. On that point are also examples of more than temple having the same trees as sthalavriksham (eg.) Aegle marmelos (L.) Corr.serr. and Azardirachta indica Adr. Juss. etc. Some of the important temple festivals are associated with the sthalavriksham of the temples concerned mavadi sevai of kanci Ekambareswara temple and makizhadi sevai of tiruvottiyur temple are two such festivals. Sthalavriksha mostly occurs in tree habit, in main or big temples of Tamilnadu. In some temples, it occurs in herb, shrub, grass or climber forms. Sacred trees are therefore handled as any other sacred space, and it is thus not surprising that many of the customs and ceremonies mentioned in sacred places, in general, are also observed at the sites of sacred trees. This habit shows characteristically the importance of medicinal plants in Indian System of Medicine. Medicinal parts of the Sacred Trees (Sthalavrikshas) are practiced in different forms. It is presented in the form of paste, juice, dried powder and made into tablets and juices mixed with sugar and honey to cure various diseases Amirthalingam [3].

Materials and Methods

Study Area

Historical Background: Madurai is one of the major districts of Tamilnadu State. Madurai is located along the bank of the river Vaigai. It is an ancient urban center known for its age old legacy and agile of contemporary modern lifestyle-a singular spot for worship and the Modern-day of living. Madurai is also visited by different names like “City of Jasmine” (Malligai maanagar), “Temple City” (Koil maanagar), “City that never sleeps” (Thoonga Nagaram) and “City of four junctions” (Naanmada koodal).

Location & Geographical Area: The Madurai district lies between 9° 56’ 20.7348’’ N and 78° 7’ 18.1884’’ E. It takes in an area of 3741.73 Sq. Km and is bordered on the west by Theni district, on the north by Dindigul district, on the east by Sivagangai district and along the south by Virudhunagar district. The district is empowered with a semi arid tropical climate with normal rainfall of 827.1 mm as against 923.1 mm for the state. The present study was extended out in Madurai district, Tamilnadu. 130 temples were enumerated, data gathered from the local people. Flowering twigs of trees set up within the temple premises were collected and identified taxonomically using the Floras. The tree species grown as Sthalavriksha in 65 temples in Madurai district were enumerated. The survey documented several interesting facets of tree worship. The local people, including Temple handoff, Priests, Temple Defendable and Worshipers was interacted with temple area of Madurai district that have indigenous knowledge about sacred plants of their locality and information’s were collected by group discussions and interviews with them in their local language (Tamil). Binomials of the plants with family, their local names, parts used and Medicinal uses were recorded (Figure 1).

Interview and Ethno Medicinal Data Collection: The ethno medicinal information was collected by interacting with the priest and people living around the temples through interview as a recorded data.

Collection of Plant: The floral parts and twigs were collected from the Sthalavriksha for Binomial name identification. Generally, the plant specimens were collected with flower and fruit. In case, if there are no flowers and fruit conditions, the plant twig with few leaves was collected for proper identification.

Result

Sthalavriksha worship in temples is an ancient religious practice in India. This study is the first attempt to survey the Sthalavrikshas of 100 temples in Madurai district. Tamilnadu, India. Of the surveyed 100 temples, there were only 68 temples in which Sthalavriksha were present. The temples found among them 12 were Lord Shiva temples, 28 were Lord Amman temples, 7 were Goddess Sakthi temples, and 7 were Lord Murugan temples, 3 were Vinayaga temples, 11 various deity temples. A total of 31 plant species belonging 20 families was recorded in the study. Most of these plants belong to Dicotyledons of angiosperms and one species belong to Monocotyledons (Borassus flabellifer L.). 30 Sthalavriksha plants were trees while one was a shrub (Tabernaemontana divaricata R.Br.ex Roem & Schult.). All the Sthalavrikshas documented in the study are given in Table 1 In Madurai district; the ancient temples were recorded for this study. The temples include Meenakshi Amman temple, Kallalagar temple, Thiruvaapudaiyar temple, Inmailum Nanmai Taruvar Temple, Puttu Sokanathar Temple etc. A total of 31 Sthalavriksha species belonging to 20 families were recorded, and Dominant families were Moraceae and Fabaceae with 4 species each, Moraceae, represented by 4 species (Ficus benghalensis L. Ficus microcarpa L.f. Ficus religiosa L. Ficus tintoria G.Forst). Fabaceae represented by 4 species (Prosopsis cineraria (L.) Druce, Pterocarpus santalinus L.f. Acacia leucophloea Wild. and Prosopsis cineraria (L.) Druce) and the other dominated families were Anacardiaceae and Mimosaceae. Each family is represented by 2 species, Mimosaceae (Albizia amara (Roxb.) Acacia nilotica (L.) Willd. ex Del.) and Anacardiaceae, includes 2 species (Lannea coromandelica (Houtt.) Merr and Mangifera indica L.) Among these Rutaceae was the dominant family represented by 16 temples followed by Moraceae represented by 6 temples and followed by Meliaceae and Rubiaceae represented by 4 temples each. The frequently occurring species was Aegle marmelos (L.) Correa recorded in 17 temples followed by Ficus benghalensis L. Druce in 6 temples and Azardirachta indica Adr. Juss and Neolamarckia cadamba (Roxb.) Bosser was recorded in 4 temples each. All the 31 species were reported to have medicinal properties. Tholkappiyavathi et al., (2013) reported that 16 temples have Sthalavrikshas while 20 such element exists in remaining temples. 9 species of Sthalavrikshas have been recorded in these 16 temples. Prabakaran et al. [4] surveyed the sthalavriksha of 106 temples in Salem, Namakkal, Karur district. They record sthalavriksha were found in 81 temples and a total 18 plant species belong to 18 genera and 14 families.Among this Caesalpiniaceae was the dominant family represented by 3 species followed by Rutaceae and Moraceae represented by 2 species each (Figure 2) .

Economically Important on Species

Most of the plants put down from sacred plants (Sthalavriksha) of Madurai district are economically significant. The medicinal plants comprise about 31 species, 29 species having timber value and 19 species were regarded for minor forest produce. Many multipurpose species have also been reported from the groves. Of these, 23 species are used as timber and medicine, 34 species as medicine and minor forest produce, 18 species as minor forest products and timber, and 10 species as timber, medicine and minor forest produce. Sukumaran et al. [5] reported 329 species belonging to 251 genera of 100 families and economically important plants such as medicinal value (194 sp.), timber value (34sp.) and minor forest product (19sp.) (Figure 3).

Quantitative Analyses of Medicinal Use

The village people have used the Sthalavriksha plants for many ills. It may be noted here that most of the sacred trees usually have great medicinal value. Traditional medicine continues to act as an important role in health maintenance. Medicinal parts of the Sacred Trees (Sthalavrikshas) are practiced in dissimilar kinds. It is presented in the form of a paste, juice, dried powder and juices mixed with sugar and honey to cure several diseases. The similar documented was made for 31 plants belong to 20 families are identified as traditional medical used species (Table 2). Gastrointestinal problems like digestive problems, diarrhea, dysentery, stomach ache and constipation were treated using specific herbal prescriptions by the local peoples same reported. Respiratory problem like cough, cold, and asthma also used medicinal plant. The plant parts, mostly reported in this regard were Leaves (29%), Bark (25%), Fruit (14), Root (12%), Flower (8%), Stem (6%), Seed (4%) and Latex (2%). Gunasekaran et al. [6] Ethnomedicinal uses of 91 Sthalavrikshas (temple trees) in Tamil Nadu, southern India, posses medicinal uses and cured various diseases like Toothache, Dysentery, Stomach ache, Diar¬rhea, etc.

Medicinal Preparations

The medicinal preparations followed by the Sthalavrikshas of Madurai district to cure a disease were based on many kinds of preparations which are as follows.

a) Decoction: A decoction was obtained by boiling the plant in water until the volume of liquid was reduced to more than ½ or ¾ of the original amount of liquid.

b) Extract: The plant material was ground with some amount of water as per the need and filtered. The filtrate was used as an extract.

c) Juice: The juice was obtained by grinding the plant material and this preparation was administered wholly (This juiciest material used for filtered or non-filtered)

d) Latex: Latex was obtained by detaching the leaf or young stem at normal region of the plants and used.

e) Paste: The paste was prepared by grinding fresh, dried material with water.

f) Powder: The powder was prepared by grinding dried material.

g) Raw: The plant material is also used in raw form, was used immediately after harvesting.

It was also likewise mentioned that the sthalavrikshas in Madurai district in Tamilnadu used the medicinal preparation mostly in the form of Paste (19%), followed by decoction (20%), juice (20%), extract (15%), Powder (9%), Raw and Latex (17%). Some of the sacred plants cure to various diseases, taken from various forms, such as Aegle marmelos species bark decoction is used to treat intermittent fever. Bark powder used for skin diseases. Leaf act as a blood purifier. Cassia fistula species taken from various forms, Leaf (paste) flower (juice) and root (extract) cured of some diseases such as skin diseases, snakebite, fever and cold. Gunasekaran et al. [6]- Ethno medicinal uses of 91 Sthalavrikshas (temple trees) in Tamil Nadu, southern India, they reported medicinal uses and taken from various formations such as juice, decoction, powder, paste, used to cure for various diseases and ailments like Diarrhea, fever, cough, cold, etc.

From the present investigation, it was noted that the Sthalavriksha plants on Madurai district of the study area used to herbal preparation made from the medicinal plants mostly used for the treatment of diarrhea (5 species: Aegle marmelos, Mangifera indica, Acacia nilotica, Morinda tinctoria, Tamarindus indica), dysentery (5 species: Acacia nilotica, Acacia leucophloea, Syzygium cumini, Tabernaemontana divaricata, Morinda tinctoria), fever (5 species: Acacia leucophloea, Aegle marmelos, Mimusops elengi, Morinda tinctoria, Neolamarckia cadamba), cough (5 species: Ailanthus excels, Acacia leucophloea, Lepisanthes tetraphylla, Prosopis cineraria, Millingtonia hortensis), skin diseases (9 species: Aegle marmelos, Azardirachta indica, Alangium salviifolium, Cassia fistula, Ficus religiosa, Millingtonia hortensis, Pongamia pinnata, Pterocarpus santalinus, Borassus flabellifer). Gunasekaran et al. [6] - Ethnomedicinal uses of 91 Sthalavrikshas (temple trees) in Tamil Nadu, southern India, they reported medicinal plants, mostly cured of fever (23 species), dysentery (13 species), asthma (10 species), rheumatism (10 species) and diarrhea (8 species). Nandkishor et al. [7] reported that the Some Sacred Trees and their Medicinal Uses from Amravati District (Maharashtra), used the medicinal plants, mostly for the treatment of fever (12 species), followed by dysentery (8 species) and diarrhea (3 species) [8-10].

Conservation Status of the Plants

The plant species Pterocarpus santalinus comes under the endangered category, all other species are of least concerned status (Table 1).

The Necessity of Security

Sthalavrikshas worshipped in plants are a means of conservation of plants. Plants in the temple gardens are cultivated and maintained and this is also a means of conservation of plants. The role of people in the conservation of plant has been an age old practice since historic period. It was concluded that the Sthalavriksha worship is an age old practice; myths, beliefs and this practice play a major role in the conservation of plants. Thus, the above results and discussion proved the relation of the human and the nature towards plant conservation. The traditional worshipping has protected many plants which have tremendous medicinal value and made them as sacred, so that with the fear of deity nobody eradicates it. So we have to protect these sacred plants for us and our next generation for better survival. On the basis of this study, we have to follow our ancestor’s belief in humanity and nature sustainability.

Conclusion

Madurai district, unitary of the ancient districts of Tamil Nadu famous for its religious culture, was studying for the sthalavriksha plants. It was noted that a total of 31 plant species was recorded. The recorded plant species belong to 20 families. Among that family of Moraceae and Fabaceae dominated together with 4 species followed by Rutaceae, Rubiaceae, Anacardiaceae and Mimosaceae family consequently represented with 2 plant species. Medicines are obtained from the Sthalavrikshas and are used in different forms. Sthalavrikshas are valued for their botanical, medicinal, environmental, religious and mythical importance. The sthalavrikshas of Tamilnadu constitute a lot of genetic resources for the conservation of species diversity. Propagation of sthalavrikshas in temples contributes to the conservation of our floral diversity. Some trees are significant for their economic use of shipbuilding or in the timber industry, some for providing homes for various animals, birds, and others for their medicinal value. In the present study, it is concluded that the religious activities are having a close relationship with plants boost up the mental health of local people of Madurai district and many of the sacred plants found in the household and temples were used for various religious cultural activities as well as for health care. These sacred plants are worshiped by the local people for getting the blessing of health and wealth by positive powers of nature. Hence the religious ceremonies, rites act as a protective factor or device for the conservation of sacred plants. So, it is the duty of the present generation to preserve and promote these aesthetic treasures to conserve biodiversity and nature, which will surely play a part in the progression of human beings. These sacred trees preserved through millennia by our ancestors as potential bio resources should be respected and conserved for the future generation. The sthalavrikshas is a mean of conservation of biodiversity.

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juniperpublishers-agriculture · 3 years ago

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Citrus Canker in Sudan: Etiology and Epidemiology- Juniper Publishers

Citrus bacterial canker disease (CBCD) caused by Xanthomonas citri subsp. citri (Xcc), is one of the most destructive diseases to the citrus plantations worldwide, newly invaded, and threatened citriculture in Sudan. Occurrence and spread of CBCD in Sudan have been surveyed in two states, representing the main citrus producing states in Sudan. Field surveys were conducted during January 2015 in commercial citrus orchards and nurseries at the two locations. Symptomatology, host range study, physiological and biochemical characterization of the isolated pathogen were also carried out to obtain important clues on pathogen identification. In addition, the pathogenicity test was performed on detached leaves of several selected citrus varieties such as grapefruit, orange and lime to establish the identity of the presumptive Xanthomonas citri subsp. citri (Xcc). The disease on lime orchards in northern and southern Sawagi (Kassala State) recorded a disease incidence of 66.6% and 18%, respectively. In nurseries, the disease incidence attained 51.7% and 53.6% in northern Sawagi and southern Sawagi, respectively, while in Khartoum State the disease was unexpectedly detected at a considerably high incidence of 45%, but at only one nursery, no disease detected in Khartoum State` s orchards during these surveys. Lime trees displayed typical symptoms of CBCD, but nearby canker-susceptible citrus species, such as grapefruit (C. paradisi) and sweet orange (C. sinensis) were unaffected. Typical symptoms of CBCD were noticed on leaves, twigs, fruits and branches. The pathogenicity tests of the recovered canker isolates induced typical lesions on local lime only, but produced atypical lesions on other citrus varieties. All the biochemical and physiological characteristics obtained from the re-isolations were also indicative of the presence of Xcc. As important perspectives, it appeared that these citrus canker isolates were distinctive and specific on lime. They were very similar to the pathotype and they attained an epidemic level in Kassala State.

Keywords: Citrus bacterial canker; Severity scale; Pathogenicity; Pathotype

Introduction

Citrus (Rutaceae family) is considered as one of the most important commercial fruit crops. Sudan, with all its vast area, wide range of soils, diverse climatic conditions, and ample water resource possesses great potentials for citrus production. At present, the commercial citrus production in Sudan spreads all over the country, mainly along the narrow strips of alluvial soils of the main River Nile, Blue Nile, and White Nile. In addition, it is also extending to the banks of annual valleys and rivers and upper terraces in which underground water is available for irrigation [1]. The important citrus groups have grown commercially in Sudan include: Small fruited acid lime (Citrus aurantifolia Swingle), grapefruit (C. paradise Macfad), sweet orange (C. cinensis Osbeck), and Mandarins (C. reticulate Blanco). Each group is composed of several varieties and selections (Ali-Dinar, 1984). The total area of citrus production in Sudan is estimated around 171,192 hectares with a total production of 2.3 million tons and exportation amounting to 9.8 thousand tons, for years (2010-2013) (National Horticulture Administration, 2013). Therefore, the national strategy of citrus expansion is directed towards the large national schemes, e.g. Gezira, Suki, Rahad and the Blue Nile Schemes in the Central Clay Plain [2]. Although the citrus crop is kept in great esteem, yet its present status is threatened by several problems, including low productivity caused by diseases. The citrus tree is attacked by several diseases in Sudan like gummosis, citrus decline, Tristeza virus, and virus-like diseases [3]. More recently a new aggressive disease was discovered in Gadaref State on lime with typical symptoms of citrus bacterial canker [4].

Citrus bacterial canker disease (CBCD) caused by Xanthomonas citri subsp. citri (Xcc) is probably one of the most devastative to the citrus plantations at the global level. Citrus canker is thought to have originated from South East Asia or India and spreading in more than 30 countries throughout the world, including countries in the Middle East, the Horn of Africa, and some other countries in South and West Africa [5,6]. Citrus canker disease is occurrence regularly on several citrus cultivars in varying degrees of incidence depending on the climatic conditions. The bacterium causes different symptoms ranging from pustules to necrotic lesions consisting of erumpent corky tissue surrounded by water soaked tissues and yellow halo on leaves, stems, and fruits [7-12]. As such, disease severity on susceptible variety results in defoliation, dieback, premature fruit drop, and blemished fruit, which consequently decrease fruit production and market value [13]. Also, the citrus canker has had a serious impact on local citrus industries whenever infections have been detected. As a result, millions of dollars are spent annually on prevention, quarantine, eradication programs, and chemical control [14]. Three main types of citrus canker bacteria have been identified, which possess variations in host range among citrus varieties.

The pathotype A (the Asiatic type of canker, Xcc) is the most destructive and widespread variant of the disease among most commercial citrus varieties and their relatives. The pathotypes B and C of citrus canker are caused by Xanthomonas fuscans subsp. Aurantifolii. Cancrosis B and cancrosis C are limited in host range and are geographically restricted to South America [15]. Certain distinctive groups within pathotype have also been identified which have restricted host range. For instance, pathotype strains with a host range restricted only to Mexican lime (Citrus aurantifolia) but not infecting citrus canker susceptible species, grapefruit and sweet orange, have been described in several countries in The Middle East and also reported from Thailand, Mali, Ethiopia, and Burkina Faso (Derso et al., 2009). Recently Elhassan et al., [4] reported the presence of CBCD for the first time on lime trees in Gadaref State (Sudan) depending on the visual symptoms, pathogenicity tests, and some biochemical characteristics of the causal bacterium isolate, which closely resemble the atypical Asiatic form of CBC . Now the disease seems to flare-up and spread to most of the citrus groves in Gadaref and Kassala states. It was also observed to spread in nurseries of Khartoum North. In general, the environmental conditions, particularly the climate are conducive to CBCD development in the remaining areas of all southeastern region of Sudan. Apparently, a high infection potential dominates the epidemiological stage in this region. The study was conducted to survey the natural occurrence, citrus varietal susceptibility, symptomatology, disease severity and extent of spread of citrus bacterial canker disease (CBCD) in commercial citrus orchards and nurseries in Kassala and Khartoum states, it was also aimed to confirm the identity of the causal pathogen depending on phenotypical characteristics and the pathogenicity of the bacterium isolates.

Material and Methods

Field survey and disease pathometry

The survey was carried out in January 2015 after the end of the rainy season in two different locations (Kassala and Khartoum states). In Kassala State, the survey was conducted in North Sawagi and South Sawagi areas, while in Khartoum State, the survey was conducted at Shambat in Khartoum North and at Almogran in Khartoum. The survey included inspection of two main citrus planting types namely, commercial orchards and nurseries. 6 orchards and nurseries per location at Kassala State and 4 from each were inspected at Khartoum State. Two hundred lime trees, in addition to 30-100 orange, mandarin, and grapefruit trees, whenever available, were examined in the same orchard inspected for the presence of CBCD. Also, all nursery stocks found at the selected sites were examined for CBCD. The main objectives of the survey were to discover the occurrence and extent of the spread of citrus bacterial canker disease (CBCD) and study its Symptomatology. Close visual observations were made and diseased plant tissues including, leaves, twigs, and fruits were collected from symptomatic plants. Disease development was then evaluated according to the following pathometry:

Disease incidence

The disease incidence (DI) was recorded for each planting type at these locations and the data were arranged and statistically analyzed. The calculations were based on the following formula:

DI (%) = No.of infected plants x 100 / total No. of plants inspected

Disease severity

i. In orchards

Ten trees were randomly selected at each orchard. Diagnostic symptoms were examined on leaves, fruits, twigs, branches, and the main tree stem. In severe cases, defoliation, twig dieback, and fruit drop were also considered. Disease severity (DS) was estimated at specified dates based on a 0-5 disease severity scale (SS) as the fallows:

Scale 0: non-symptomatic trees. Scale 1: leaf symptoms on few (1-3) branches, Scale 2: leaf symptoms in up to 10% of branches. Scale 3: leaf symptoms in >10%-25% of the branches plus mild symptoms on fruits and twigs. Scale 4: >25% -50% of the tree canopy showing clear canker symptoms on leaves, fruits, twigs, in addition to defoliation and die-back. Scale 5: > 50% of the tree canopy showing prominent canker symptoms on leaves, twigs, fruits, main branches, and trunks. Also, severe defoliation and dieback are evident.

ii. In nurseries

Disease severity was estimated based on a 0-5 disease severity scale (SS) as follow:

Scale 0: non-symptomatic nursery plants. Scale 1: leaf symptoms on few (1-3) leaves. Scale 2: leaf symptoms on 4 to 9 leaves Scale 3: leaf symptoms on 10 to 15 of the leaves. Scale 4: leaf symptoms>15 leaves to 50% of the foliage. Scale 5: > 50% of foliage showing canker symptoms. Besides, some individual lesions on twigs and stems are evident.

The disease severity (DS) was then calculated as follow:

3- Percent disease index (DX): It was calculated according to the fallowing formula:

DX (%) = DS x 100/ max SS

The recorded data on disease pathometry (disease incidence and disease index) were transformed using arcsine transformation, before being subjected to analysis of variance (ANOVA), as described by Gomez and Gomez (1984) for the factorial experiment in a completely randomized design. EXCEL computer package version 2010 was applied. Then the treatments means were compared using the least significant difference (LSD).

Symptomatology

Symptoms development of citrus bacterial canker infection was closely examined during the survey of the disease in each of chosen orchards and nurseries. Different parts of symptomatic trees were examined for canker lesions namely, leaves, twigs, fruits, branches, and stems. Also, leaf defoliation and die-back in twigs and branches were also observed, recorded, and photographed. The symptoms were closely noticed and described.

Isolation and purification of Xanthomonas axonopodis pv. citri

Isolation and purification of the bacteria from infected leaves, fruits, and twigs were conducted following the National Diagnostic Protocol for Asiatic Citrus Canker [16].

Pathogen identification

Morphological, biochemical and physiological characteristics of bacterium isolates including gram staining reaction, growth on YDC medium, starch hydrolysis, growth at 36 oC and 40 oC test, motility test, anaerobic growth, KOH Solubility test, (1-3%) NaCl Tolerance, gelatin liquefaction test, Tween 80 lipolysis and catalase test have been conducted according to Verniere et al [17], Goszczynska et al [18] and Kidist [19].

Pathogenicity Test

Pure isolates of the bacterium were grown on nutrient agar plates and incubated at 28℃ for 24 h. Bacterial cells were then harvested in sterile distilled water by using a sterile glass rod and the bacterial suspension was adjusted finally to give 1.0 × 108 CFU/mL using a UV spectrophotometer at a wavelength of 600 nm (Sunrise Spectrophotometer, Tecan). Immature fully expanded ‘Mexican’ lime and ‘Marsh’ grapefruit, Valencia orange, Eureka and Mandarin leaves were sterilized by soaking for 2 min in 1% sodium hypochloritae followed by rinsing in sterile distilled water. Leaves were placed on the surface of 1% water agar with their abaxial surfaces facing upwards. Six wounds were made per leaf with a needle and droplets (10 microliters) of bacterial suspensions were placed on each wound. Leaves were incubated at 280C with a photoperiod of 12 h light and 12 h dark for 2 weeks.

Results

Field survey and disease pathometry

The survey conducted in commercial citrus orchards and nurseries in both Kassala and Khartoum States indicated the occurrence of citrus bacterial canker (CBC) on lime (Citrus aurantifolia Swingle), but not on the other surveyed citrus varieties. While the typical disease symptoms in Kassala State were evident in both citrus orchards and the nursery lime seedlings, they were only displayed in the nursery stock and absent in orchards in Khartoum State. The combined disease development of the two planting types (orchards and nurseries) in Kassala State was consistently significantly (P ≤ 0.05) higher in Sawagi North compared to that in Sawagi South (Table 1). Separately, CBC development on each planting types was as follows:

i. In orchards

The results of the disease Incidence, severity, and disease index are shown in Table 1. The disease was recorded in all surveyed commercial orchards in Kassala State. While Sawagi North recorded significantly (P ≤ 0.05) higher CBC incidence (66.6%) comparatively low disease level was recorded in Sawagi South (18%). Similarly, more severe CBC (3 fold as much) was encountered in Sawagi North with a disease index, which was significantly (P ≤ 0.05) higher (64.9%) than that recorded in Sawagi South (25.3%). However, the disease was not detected in citrus orchards in Khartoum State.

ii. In nurseries

Citrus bacterial canker disease was recorded in all the surveyed nurseries in both locations of Kassala State (Table 1). North Sawagi recorded 51.7%, 2.1 and 52% CBC incidence, severity, and disease index, respectively. Comparable CBC development was noticed in South Sawagi indicating 53%, 1.8 and 51.5% incidence, severity, and disease index respectively. However, In Khartoum State, the disease was detected in 45% of lime plants in only one nursery in Khartoum North with an overall mean disease incidence of 12.6%, moreover, 0.7 and 21.2% CBC severity and disease index were recorded respectively.

Symptomatology

Typical symptoms were observed upon examination of 'local' lime trees infected with CBC (Figure 1). These characteristic external symptoms were cankerous pustules and necrotic lesions consisting of raised or erumpent corky tissues on leaves, fruits, twigs, thorns, and branches. The canker lesions on leaves and fruits were surrounded by a water-soaked ring and often with a prominent yellow margin. Also, lesions with a shot hole-like appearance were found. Unusual canker lesions were also commonly encountered on the leaves, which were associated with mechanical (i.e. thorn) and leaf miner damages. Many of these canker lesions coalesced to form elongate or blotchy corky patterns on the affected leaves. Frequently, severe infections were encountered in some surveyed orchards which largely covering. In severe cases of foliage infection, extensive leaf defoliation and die-back symptoms were observed. The fruits were particularly susceptible to the canker pathogen, usually developing severe canker lesions with crater-like centers and severe gummy exudates. Which ultimately led to piles of fallen fruits underneath the affected lime trees. In nurseries, severe canker symptoms were also observed on leaves, twigs, and stems (Table 2).

Pathogenicity test on detached leaves:

The typical canker lesions observed on infected lime leaves were reproduced only on lime in response to the pathogenicity test performed on detached leaves. On day 7 post-inoculation small white callus developed on lime leaves at the six inoculation points (Plate 12A). Advanced callus formation gradually changing to tan color lesions surrounded by water-soaked area and yellow halo were produced on lime leaves as time progressed to 20 days after inoculation (Plate 13A). A typical symptom of flat lesions developed on sour orange, ʻValenciaʼ orange, and ʻBaladiʼ mandarin (Plates 13B, 14A, 14B). However, ʻEurekaʼ lemon, ʻMerkisʼ mandarin, and grapefruit (Red blush and March) failed to produce any symptoms (Plates 15 and 16) similar to the control treatment inoculated with sterile distilled water (Figure 2).

Discussion

The citrus bacterial canker disease (CBCD) has become established and attained an epidemic status in different parts of Sudan. Although the disease has not been known before 2013, its emergence in autumn 2014 was somewhat overwhelming and so intriguing. It infested the main citrus growing areas of Kassala State which represents the most important commercial producing region in the country, particularly the North Sawagi and the South Sawagi localities recording considerably high CBCD levels (incidence of 66.6% and 18% and disease indexes of 64.9% and 25.3%, respectively). This outbreak is believed to have been caused through a long-distance spread, which more often occurs with the movement of infected propagating materials such as nursery stocks, budwood or budded trees, or through contaminated environmental factors such as nursery workers carrying the bacteria on hands, clothes, and contaminated budding tools [11]. Alternatively, the spread of canker bacteria may have occurred during strong wind-driven rains coming from Gadaref State or across the borders from Ethiopia (Derso et al., 2009) or Saudi Arabia [6]. The fact that CBCD was first detected in some Gadaref State localities only a year before it appeared in Kassala, would indicate that the path of the disease was most likely: Ethiopia- Gadaref then Kassala. This could be substantiated by the discovery of the disease several years ago in Ethiopia (Derso et al., 2009) and only recently in commercial citrus orchards and nurseries of Gadaref State [20]. The bacterial inoculum might have been present in Kassala in the same year of the discovery of CBCD in Gadaref, but it has been overlooked since the pathogen is known to survive epiphytically at low population levels on citrus hosts without symptoms development, and in association with other weeds and grass hosts [21,22]. However, the bacteria survive primarily in naturally occurring lesions. Cankerous leaves, twigs, and branches constitute the main source of the inoculum, but the prominent occurrence of lesions is seasonal, coinciding with periods of heavy rainfall, moderate temperature, and growth flushes. The pathogen can survive up to 6 months or more in the infected leaves [23] and up to 76 months on diseased twigs [24].

In comparison, the greater CBCD development in the Northern Sawagi over that in the Southern Sawagi can be attributed mainly to the topographical factors of Kassala State heights (≤ 850 m a.s.l). These heights may retard the wind speed in South Sawagi, while in North Sawagi orchards on the other side exposed to wind-driven that may carry the bacterial inoculum. Also, the variation of disease pathometry may have a direct relation to differences in the prevailing cropping systems in the two locations. For instance, the mixed plantation of lime /mango system makes southern Sawagi trees less infected because of the windbreak effect created by mango trees. This is not surprising since cankers develop more severely on the side of the tree exposed to wind-driven rain. [25]. Although this variation in CBCD level is perceivable in the first year of the appearance of the disease, it is unlikely to persist if the locally prevailing epidemiological factors remain remarkably similar in the two locations.

On the other hand, CBCD was absent in Khartoum State, be it in commercial citrus orchards or nurseries, except in one nursery of lime seedlings in Khartoum North. This was perceivable since the prevailing environmental conditions were not conducive for CBCD development [26]. The remarkably high CBCD incidence reported in that nursery (45%), however, was believed to have resulted from a consignment of infected nursery stock brought from infested wet areas such as Kassala or Gadaref. It may constitute a potential threat, at least in localized small pockets in Khartoum State where the temperature and humidity may allow for a limited occurrence and spread of the disease. The study also demonstrated that the epidemic was naturally occurring and spreading on acid lime trees (Citrus aurantifolia) but not on other citrus varieties, even if they were close to the diseased lime trees. This strongly indicates that this citrus canker bacterial isolate is restricted to lime. The host specificity of this canker bacterium to lime was like that from Gadaref [20], which would further support the notion that it originated from Gadaref. The canker bacterium isolates which are specific to lime have also been previously reported from Maldive islands [26], Southwest Asia [5], Ethiopia (Derso et al., 2009), and the western region of Saudi Arabia [6]. The fact that the pathogenicity tests of the isolated bacterium developed characteristic lesions only upon artificial inoculation of detached leaves of lime and failed to induce any cankerous lesions typical of citrus bacterial canker (CBC) on grapefruit, sweet orange, or on other citrus varieties tested was a strong indication that the present bacterial isolate may belong to a special group of strains designated as pathotype A*. Although closely related to the ordinary A pathotype, these strains can be readily distinguished from the former, based on their atypical combination of host range and symptomatology [5]. Additional strains with similar biological behavior were reported by [7] and were also included in this distinctive group (i.e. A*). Although this bioassay has been found in both specific and sensitive diagnostic methods for CBC [8] the molecular analysis will certainly establish the correct identity of the bacterial isolates spreading in Kassala and elsewhere in Sudan. Collectively, the association and isolation of Xanthomonas sp. from symptomatic lime trees, together with the symptomatology, biochemical characterization, and pathogenicity tests strongly indicate that the currently investigated disease on lime in Kassala and Khartoum states is CBC (X. citri subsp. citri) and these lime isolates are closely related to the strains of the atypical Asiatic pathotype (Xcc- A*) [27-32].

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omc-juniperpublishers · 4 years ago

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Quality by Design in Enzyme Catalyzed Reactions-JuniperPublishers

Journal of Chemistry-JuniperPublishers

Abstract

Quality by Design is the new-age path chosen towards achieving the demanding quality standards in pharmaceutical industry. The present paper aims to throw light on Pharmaceutical Quality byDesign (QbD) and how its implementation will help manufacture better quality of Pharmaceuticals. Quality by Design is introduced along with its key elements to help make the understanding process easier. To attain built-in quality is the primary objective of Quality by Design. Finally, it can be said that the quality that is achieved by end product testing is not something that can be guaranteed unlike the quality assurance that can be provided by Quality by Design.

Keywords: Quality by Design (QbD); Quality Target Product Profile; Design Space; Critical Quality Attributes

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Introduction

“Quality Can Be Planned.”-Joseph Juran

The above quote is self-explanatory when it comes to product quality in the pharmaceutical manufacturing industry. Quality by design (QbD) is not very old but a recent inclusion in the pharmaceutical industry. It`s sole objective is to achieve better quality standards that is especially important in the pharmaceutical industry. The QbD approach consists of various components, important ones being risk assessment, assessment and management of the identified risks, design of experiments (DoE), quality target product profile (QTPP), and establishing a control strategy to keep the product within the design space that was created with the QbD study [1]. Out of all the components, a lot of pharmaceutical development studies have incorporated DoE for a more rational approach [2].

The target of analytical QbD approach is to establish a design space (DS) of critical process parameters (CPPs) where the critical quality attributes (CQAs) of the method have been assured to fulfil the desired requirements with a selected probability [3-4].

The principles that are involved in the pharmaceutical development and are relevant to QbD are all described in the ICH guidelines (ICHQ8-11) [5].

Any Pharmaceutical Development Process Typically Covers the Following Sections:

a) Complete portfolio including all the details as well as analysis of the Reference Listed Drug Product

b) Quality Target Product Profile (QTTP) compilation.

c) Figuring out the Critical Quality Attributes (CQA)

d) Complete characterization of API &CMA (Components of Drug product) identification of the API

e) Excipient selection& excipients CMA identification

f) Formulation Development

g) Manufacturing Process Development [6]

Quality Target Product Profile (QTPP) describes the design criteria for the product, and should therefore form the basis for development of the CQAs, CPPs, and control strategy.

Critical Quality Attributes (CQA) – A physical, chemical, biological, or microbiological property or characteristic that should be within an appropriate limit, range, or distribution to ensure the desired product quality (ICH Q8) Critical Process Parameter (CPP) – A process parameter whose variability has an impact on a CQA and therefore should be monitored or controlled to ensure the process produces the desired quality. (ICH Q8) Critical Process Parameters (CPP) identification and their impact analysis is done by conducting a preliminary risk analysis for every process parameter (PP) that is involved in the individual unit operations.

Need for QbD in Pharmaceutical Industry [7,8]:

a) To integratepatient needs, quality requirements and scientific knowledge all in one design while the pharmaceutical product is still under developmentand further extending to the manufacturing process.

b) To have a better understanding about the impact of raw materials and process parameters on the quality of the final product. This is especially important for biopharmaceutical products since raw materials like cell culture media can be the risk for variability, effecting important factors likecellular viability, cell growth and specific productivity.

c) To collaborate closely with rest of the industries and the regulators and successfully keep up with the regulatory reviews

d) To maintain harmonization in all the regions so that a single CMC submission worldwide is all that is needed.

e) To encourage continuous quality improvement for the benefit of patients.

f) To enable better product design that will have less problems while manufacturing, thus facilitating more efficiency in the manufacturing process.

g) To make post-approval changes easier since it will be contained within a pre-defined design space, thus resulting in regulatory flexibility.

Every production process in a pharmaceutical industry to implement certain control strategies with the ultimate goal of a robust process. A robust process is the gateway to high product quality at the end of the day [9]. Process variability stands as a hurdle to process robustness, and this originates from lack of control on the process parameters. Thus, QbD steps-in to avoidbatch to batch variability in pharmaceutical products [10].

The net outcome of the detailed QbD study (applied in any product) is the segregation of process parameters with respect to their criticality and the finalization of a proven acceptable range (PAR) for every operation. The knowledge that is gained post the QbD evaluation encompasses every minute detail of the operational process as well as the product in general, and lead to the defining of a Design Space. This way, the impact that the manufacturing process might have with regard to the variability of the CQAs becomes apparent, which helps in strategizing testing, quality and monitoring of batches [11].

Process Evaluation: Linking Process Parameters to Quality Attributes

It is important to carefully evaluate the process completely before applying QbD to it. The better knowledge you have of the process, the more effective your QbD will be. Moreover, process characterization is required to specify the proven acceptable ranges (PAR) for critical process parameters (CPPs). In the traditional approach that is implemented in biopharmaceutical production, existing empirical process knowledge is used on a daily basis. However, this approach leads tolaborious and time consuming post approval changes during process adaptation and any new technology implementation that may have become necessary for raising the efficiency of the process. Also, the effects aprocess scale-up can have on the quality of the final product cannot be predicted when using the empirical process development.

This can increase costs and also can cause difficulty in implementing any changes in the set manufacturing process. Thus was born a way to achieve deeper understanding of processes which would lead to greater flexibility and freedom to effect changes. The concept of operation under a pre-defined design space gave this flexibility. Design space is nothing but a concept that is a part of the “Quality by Design” (QbD) paradigm. Now, manufacturers are to follow a science-based process development than their empirical counterpart.

The QbD Concept is Best Explained in this Flowchart Below

Define a Quality Target Product Profile (QTPP) for product performance

⇩

Identify its Critical Quality Attributes (CQAs)

⇩

Create experimental design (DoE)

⇩

Analysis done to understand the impact of Critical Process Parameters (CPP) on CQAs

⇩

Identify and control the sources of variability.

Process characterization sets the ball rolling in any process development, which employs a sound risk assessment rating the various critical process parameters according to their importance [12-14].

Downstream Processing in Biotransformation

Downstream processes of biopharmaceutical industry essentially include the following steps:

a) Harvesting

b) Isolation

c) Purification

Various unit operations that constitute any biopharmaceutical process follow a designed sequence to form an integrated process [15]. Thus, any change in any one of the one-unit operation can affect the functioning of the subsequent unit operations. This is the reason why interaction effects between participating parameters across unit operations should also be taken into account during the process development. Interactions are said to happen when setting of a parameter will show effect on the response of another parameter. Due to this dependence between the parameters, the combined effects of any two parameters hailing from different unit operations cannot be predicted from their individual effects. Regulatory authorities demand inclusion of interactions of parameters within the QbD approach during any process optimization [16]

Example: Downstream processing of 1, 3-propanediol

Process: Fermentation

Fermentation broth that uses flocculation, reactive extraction, and distillation was studied. Flocculation of soluble protein as well as cellular debris that were present in the broth was carried out by using optimal concentrations of chitosan (150 ppm) and polyacrylamide (70 ppm). It was seen that the soluble protein that was present in the broth decreased to 0.06 g L-1. Recovery ratio (supernatant liquor: broth was found to be greater than 99% (Figure 1) [17,18].

The above flowchart shows a typical fermentation process broken down in steps. Glycerol fermentation process is taken as example for the illustration [19].

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Case Study for API

API product development from the very nascent stages require a lot of planning when implementing QbD at every stage. Whether it is two-step process or a multi-step process, each and every operation and parameter needs to be scrutinized before creating a relevant design space. Brainstorming every possible roadblock that might threaten the quality of the final pharma product is what will help design a top-quality process. A futuristic vision is important in the initial steps of QbD planning. The most important part is to pay sufficient attention to detail lest critical aspects might be missed. This is best done by sitting with the entire development team and taking every minor detail into account. Given below is a case study for a API intermediate development process with the help of QbD that highlights the important steps as to how to go about implementing it from the very beginning of your research. QbD is done best, when it is implemented from the very nascent stage of product development.

Quality Target Product Profile

When making your QTPP, make sure you list down everything from your vendor details to target costing. This step basically asks you to think of every aspect of your product and make a comprehensive profile of it. The specification of quality must be highlighted here with all the challenging impurities that might threaten your quality. Everything from stability testing requirements to raw material quality [20] is encompassed in this stage of QbD.

CQA Determination

Given below are some typical CQA parameters that are considered in most of the enzymatic methods of API intermediate preparations.

a) Purity

b) Chiral purity

c) Enzyme residue

d) Assay

e) Appearance

f) Residual Solvent

g) Yield

h) Polymorphic forms

i) Moisture content

j) Melting point (Table 1)

Initial Risk Assessment

The risk assessment can be done in various ways and is the customizable step in QbD. This part calls for a group-discussion or a team meeting where everyone can list down all possible risks related to the project in discussion and grade each one in the list with the amount of risk that it poses. The simplest module suggests you number them 1, 2, 3 with the increasing or decreasing order of the risk threat. A more complicated and detailed risk assessment requires linking of CQAs and CPAs to highlight the risk of their interdependence (Figure 2) [21].

Post risk assessment, comes the control strategies to be followed to tackle the possible risks that are probable. The control strategies are for you to think and execute to achieve your target quality specifications.

Design of Experiment

This is a valuable tool for channelizing your experimental work, to move ahead in a systematic manner. Design of experiments can be of several types: comparative, screening, response surface modeling, and regression modeling [1].

Comparative Experiments: The aim of this study is simple, i.e., picking best out of two options. The selection can be done by the comparison data generated, which is the average of the sample of data.

Screening Experiments: If you want to zero-in on key factors affecting a response, screening experiments would be the best bet. For this, list down concise list of factors that might have critical effects on response that you desire. This model serves as preliminary analysis during development studies.

Response Surface Modeling: Once you have identified the critical factors that affect your desired response, response surface modeling comes handy to identify a target and/or minimize or maximize a response.

Regression Modeling: This is used to estimate the dependence of a response variable on the process inputs.

A step by step guide is given for the DoE step of the QbD process (Figure 3).

Response columns were filled post experimentation as per the design creation (Figure 4).

Factorial Design Analysis Done as Given Under

Analysis Done First for One of the Responses, “Yield”: (Table 2)

P-Values Were Checked for Significance and Higher P-Value Term Eliminated First to Create a Reduced Model:

(Table 3) (Figures 5 & 6)

Observation

From the above graph, significant interaction between the two terms can be inferred.

Analysis Done for the Response “Diacid”: (Table 4)

P-values Checked for Significance and Higher P-Value Term Eliminated First to Create a Reduced Model: (Table 5) (Figure 7)

Observation

From the above graph, significant interaction between the two terms can be inferred.

Response Optimizer Was Used to Optimize Both The Terms With Respective to The Given Responses- Yield and Diacid: (Table 6) (Figure 8)

The optimized parameters predicted for maximum yield and minimum impurity (of di-acid) was found to be 8pH and 37C.

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Case Study 2

As mentioned before, regression analysis is another important tool that can be used to study existing data. This means that if you have done some experiments (without designing them beforehand), you can quickly run a regression analysis of the collected data to derive a relationship between CPPs and the reaction results.

A lot of times, when one follows the one-factor-at-a-time optimization process, by the time any CPP is optimized, a lot of data stands generated. Instead of just tabulating the data and wasting time manually making sense out of them, regression analysis can come to your rescue. As always, graphical data representation seems much easier to understand and also saves your valuable time.

The effect of pH was studied [22] separately in the preparation of deoxynojirimycin base (stage III). The reaction involved N-formyl amino sorbitol, water, oxygen and whole cells of Gluconobacter oxydans DSM2003. Later involvement of sodium hydroxide and sodium borohydride gave rise to deoxynojirimycin. Further work-up and 2-methoxy ethanol facilitated crystallization yielded Deoxynojirimycin base. In this experiment, pH of the reaction was changed to find out its role during the reaction and a regression analysis was run using Minitab to study this affect.

Observations recorded showed that reaction did not occur at pH2 and at pH8, the reaction did not reach completion. The optimum pH range between 4 to 6 showed certain effect on yield and purity. The significance of pH variation during the reaction was thus established as described below (Graphs 1-3):

When null hypothesis p-test was carried out, no significant effect of pH was to be found on product purity, impurity1 and impurity2, but its significant influence was seen in minimizing impurity3.

Furthermore, large-scale batches conducted were statistically analyzed as well to achieve better understanding of the influence of list of parameters on the output obtained. The following parameters were studied during the stage III reaction described above:

a) pH, RPM and Oxygen cylinders consumed during the course of the reaction.

Their effect on the output and reaction completion time was studied. It was seen that only RPM showed statistically significant effect on the reaction completion time and rest of the factors did not contribute to any significant effect on the output or reaction completion time.

During biotransformation process, i.e. during oxidation of N-formyl using Gluconobacter oxydans DSM2003 whole cell, three main unknown impurities peaks were observed in HPLC chromatogram while reaction monitoring. This process is capable of removing these three impurities during down streaming, work up & isolation to the levels mentioned below:

a) Impurity 1 (has defined RRT on HPLC chromatogram) not more than 3%

b) Impurity 2 (any other unknown impurity) not more than 1%

c) Impurity 3 (has defined RRT on HPLC chromatogram) not more than 10 %

Since higher level of impurities affect the yield of the process, efforts were carried out to study the factors which can reduce the formation of process impurities.

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Conclusion

The concept of Quality by Design (QbD) is highly reliable when it comes to achieving foolproof quality of your product. This is a modern tool that is going viral in Pharmaceutical industry especially because this industry demands high quality standards and tolerates no compromise when it comes to the quality. Breaking down QbD, it essentially comes down to identifying the critical parameters of the process and assigning a particular design space for every single critical attribute. Thus, QbD can be considered as an intelligent approach to quality that yields robust processes. QbD also ensures that there is continuous improvement in the process during the entire lifecycle of a Pharmaceutical product [23].

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Acknowledgement

Our group would like to thank the Department of Scientific and Industrial Research India, Dr. Hari Babu (COO Mylan), Sanjeev Sethi (Chief Scientific Office Mylan Inc); Dr. Abhijit Deshmukh (Head of Global OSD Scientific Affairs); Dr. Yasir Rawjee {Head - Global API}, Dr. Sureshbabu Jayachandra (Head of Chemical Research); Dr. Suryanarayana Mulukutla (Head Analytical Dept MLL API R & D) as well as analytical development team of Mylan Laboratories Limited for their encouragement and support. We would also like to thank Dr. Narahari Ambati (AGC- India IP) & his Intellectual property team for their support.

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juniperpublishers-gjorm · 5 years ago

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Metformin Reduces the Extent of Varicocele-Induced Damage in Testicular Tissue

Authored by: Erkan Erdem*

Introduction

Varicocele is an abnormal vascular dilatation of pampiniform plexus, commonly developing at puberty. Although underlying mechanisms remain poorly understood genetic background, anatomical aberrations, incompetence of venous valves, difference between the drainage of left and right testicular veins were suggested in the etiology [1]. As left spermatic vein being longer than the right vein, it is more commonly incurred to increased hydrostatic pressure and dilatation. Compression of the left renal vein between the aorta and the superior mesenteric artery may also contribute to the disturbed intravenous pressure [2].

The prevalence of varicocele varies between 15-20 % in general population and 30-40% in infertile men, and 11-19% of adolescents [3-6]. It was reported that varicocele is a progressive disease and early diagnosis and treatment in youth may enhance fertility potential [7]. Several contributing factors in the pathophysiology of varicocele have been proposed such as higher temperature of testis, the disorder of neuroendocrine system, autoimmunity, accumulation of renal and adrenal metabolites, genetic and epigenetic factors, hypoxia and oxidative stress [8-10].

Varicocele represents a chronic process within the testicle, which is linked to increased reactive oxygen species (ROS) beyond physiologic limits and, subsequently, disrupting sperm membrane fluidity, causing DNA damage and necrosis [11]. Moreover, superoxide dismutase 1, glutathione S-transferase M1 and T1 which are counteracting free superoxide radicals in cells have been reported to be decreased in men with varicocele, that may be important on disturbed sperm parameters [12]. Apoptosis of germ cells was also demonstrated in the pathogenesis of varicocele-related infertility [13]. Clinical findings suggest that surgical repair of varicocele may decrease seminal oxidative stress levels and sperm DNA fragmentation and, thus, may improve sperm quality [14]. Therefore, surgical intervention seems to be a reliable option in the treatment of varicocele-related male infertility, although some controversial reports exist.

Additionally, anti-oxidant medications such as kallikrein, L-carnitine with L-acetyl carnitine, pentoxifylline, coenzyme Q10 have been used to improve the milieu in the testis in men with varicocele [15]. Metformin is a major therapeutic agent in the treatment of type 2 diabetes mellitus as an insulin sensitizer, which decreases hepatic glucose output and increases peripheral glucose uptake. Although its action was not fully elucidated, metformin attenuated intracellular reactive oxygen species and apoptosis in aortic endothelial cells, myocardium, renal tubular cells and testicular cells [16-20].

Aim

Potential effects of metformin on varicocele-induced testicular damage have not been studied in neither humans nor in animal models. Thus, we investigated the impact of metformin on spermatogenesis, testicular integrity, and apoptotic activity in the testis of adolescent rats with experimentally-induced varicocele.

Materials and Methods

Thirty-six male adolescent Wistar rats (6-week-old) were randomly and equally divided into six experimental groups. Surgical procedures were carried out under anesthesia with intraperitoneal injection of ketamine (50 mg/kg). The experimental groups were as follows:

• (C) Control group; no surgical procedure was performed, and testis was examined after removal.

• (S) Sham group, a midline incision was performed, and testis was examined 8 weeks later.

• (V) Varicocele - only group: Experimental varicocele was induced by partial ligation of left renal vein with

Silk suture at the area medial to the insertion of the adrenal and spermatic vein into renal vein as described previously [21].

• (V+M) Varicocele + metformin group: All rats were treated with metformin (300 mg/kg per day by oral gavages) for 8 weeks following induced varicocele.

• (V/E) Varicocele + varicocelectomy group: Varicocelectomy was performed 4 weeks and the examination of the testis 8 weeks after the induction of varicocele. No medication was used.

• (V/E+M) Varicocele + varicocelectomy + metformin group: Varicocelectomy was performed 4 weeks after the induced varicocele. Metformin treatment (300 mg/kg per day by oral gavages) was initiated after the induction of varicocele and continued for 8 weeks. Left testes were examined 8 weeks after the induction of varicocele in all varicocele - induced groups. As maximum apoptotic activity initiates approximately 28 days after the induction of varicocele the procedure of varicocelectomy was performed 4 weeks after the formation of varicocele [22].

Histologic preparation and evaluation

The testicular tissue was fixed in Bouin’s solution (75% picric acid, 5% glacial acetic acid, and 25% formaldehyde) and embedded in paraffin blocks. Sections (5 μm) were formed, deparaffinized, and stained with hematoxylin and eosin. Spermatogenesis was examined in each group using Johnsen’s score (a score of 1-10 was assigned to each tubule regarding epithelial maturation) as described previously [23]. Sections were examined in a random order under a standard light microscope with 10x and 40x magnification by a blinded histologist; unaware of which group each rat belonged to. Histological grading was done by examining approximately 80 randomly selected seminiferous tubules per rat. Thus, a total of approximately 480 seminiferous tubules were scored for each group.

Histomorphometry analysis

A total of 103 randomly selected seminiferous tubules stained with hematoxylin-eosin were analyzed in each group. The presence of round spermatid stage (RSS) and primary spermatocyte stages (PSS) were assessed as described previously and compared among the groups [24].

Immunohistochemical staining for cleaved caspase-3 and ImageJ analysis

Cleaved caspase-3 was used for immunohistochemical staining. Testicular tissue samples were immediately fixed in 10% neutral-buffered formalin, embedded in paraffin, and sectioned (5 μm). Sections were deparaffinized and blocked for endogenous peroxidase activity with methanol containing 3% H2O2 for 10 m. Ultra V Block (Lab vision, Freemont, CA) for 7 m at room temperature. Cleaved Caspase-3 (#9664, Cell Signaling, U.S.) was applied at a dilution of 1: 500 and incubated overnight at +4 °C in a humidified chamber for nonspecific binding. The sections were washed in phosphate-buffered saline (PBS) and incubated with biotinylated horse anti-rabbit IgG (3 mg/mL; Vector, Burlingame, CA) at a 1: 500 dilution for 1 h at room temperature.

Antibodies were detected using a VECTASTAIN avidinbiotin complex (Vector PK 4000) for 30 m at room temperature. Antibody complexes were visualized after incubation with 3,3’-diaminobenzidine tetrahydrochloride (DAB, Bio-Genex, San Ramon, CA.) and were mounted under glass coverslips in Entellan (Merck) and then evaluated under a light microscope. Immunohistochemical staining for cleaved caspase-3 was analyzed by counting 100 seminiferous tubule cross-sections in each group and expressed as the apoptotic index. In each photomicrograph, the following parameter was measured with ImageJ software: expression levels of cleaved-caspase-3 in both groups at round spermatid stage (RSS) of testes. Each of this parameter was measured 3 times for each image and the average of the 9 measurements of each sample was used for the statistical analysis. Histopathological features examined in rats with normal testis and with sham, varicocele, varicocele+ metformin in a subjective scoring (0 - not present; 1 - low grade; 2 - moderate grade; 3 - high grade; 4 - very high grade).

Statistical analysis

Histopathological findings (Johnsen’s score) were assessed by nonparametric Kruskal-Wallis test, and the mean Johnsen’s score was used in the comparison of the groups. Multiple comparisons were made using Tukey’s procedure. p<0.05 was considered statistically significant. Analysis of variance was used for statistical analysis of the apoptotic index among the groups.

Results

Assessment of spermatogenesis

Johnsen’s score was significantly lower in V group (4.14±1.25) compared to C group (9.1±0.3) or S group (9.0 ± 0.2) groups (p<0.05). V+M group had significantly higher score (6.9±0.6) than V group (p<0.05). V/E group and V/E+M group had similar Johnsen scores (8.9 ± 1.02 and 9.2 ± 0.6). These findings suggest that the administration of metformin resulted in 40.6% of improvement in spermatogenesis in rats with varicocele. However, this favorable effect was not observed when metformin was used along with varicocelectomy.

Histological and morphological changes in seminiferous tubules

Histological and morphological changes in the testes of rats were compared via hematoxylin and eosin staining and degenerated tubules (DT) were only detected in V and V+ M groups, not in C, S, V/E and V/E+M groups (Figure 1). Visual assessment of the disorganized seminiferous tubules further supported these findings as seen in Figure 2. Seminiferous tubule degeneration scores were used for quantification of data (Figure 2b). V group had significantly higher scores of RSS and PSS compared to C and S group (2.6±0.8 and 3.7±0.4; 0.2±0.4 and 0.2±0.4; 0.9±0.6 and 0.6±0.7, respectively) (p<0.05). V/E group had significantly lower RSS (0.7±0.8) and PSS (0.8±0.7) scores than V group (p<0.05). V+M group had significantly lower RSS and PSS scores (1.8±0.7 and 2.6±0.7, p<0.05) in comparison to V group, implicating beneficial effects of metformin in rats with varicocele. When compared to V/E group, V/E+M group did not exhibit any difference in RSS (0.6±0.6) and PSS (1.4±0.5) scores, suggesting the absence of additive positive effect of metformin in varicocelectomies rats.

Apoptotic activity

Apoptotic activity was assessed by using cleaved caspase 3 expressions levels, staining of cleved caspase 3 positive seminiferous tubules were shown in Figure 3a. Cleaved caspase 3 expressions were significantly higher in V group (3.5 ± 0.5) compared to C (0) and S (0.2 ± 0.4) groups. V+M group had significantly lower cleaved caspase 3 level (3.0 ± 0.7) than V group. V/E group had lower cleaved caspase-3 expression levels (1.0 ± 0.7) compared to V group. Treatment of varicoceleectomy rats with metformin (V/E+M) did not further reduce apoptotic activity in the seminiferous tubules (1.75 ± 0.43) when compared to the varicocelectomy group (V/E) (Figure 3b).

Discussion and Conclusion

The present study demonstrates that metformin can reduce the extent of testicular damage in rats with varicocele, although having no effect in rats following varicocelectomy Spermatogenesis, seminiferous tubule integrity and the degree of apoptosis were improved using metformin in the presence of varicocele although it was not as remarkable as what was obtained through varicocelectomy. A review of the literature revealed that the impact of metformin on varicocele was not investigated in humans or animal models until now.

Although it is a commonly identified abnormality not all men with varicocele present with infertility. Some intrinsic factors may render some men to become susceptible to varicocele, thus, the best candidates who benefit from varicocelectomy yet to be clarified. Since oxidative stress was shown to be important in the pathophysiology of varicocele some agents have been used to improve the milieu in the testis [1]. A number of anti-oxidant medications have been studied to relieve detrimental effects of varicocele in the testis [25]. These agents have been used either alone or as an adjuvant therapy with surgery. However, surgery remains the treatment of choice and there exists insufficient data to recommend medical therapy in men with varicocele. Barekat et al. [26] reported that administration of an antioxidant agent N-acetyl cysytein as an adjunct therapy improved semen quality following varicocelectomy [26]. Tek et al. [21] demonstrated that vascular endothelial growth factor decreased apoptosis in varicoceleinduced rats as evidenced by diminished caspase-3 positive cells [21]. Both studies showed the benefit of these as adjunct therapy following varicocelectomy. However, in the present study metformin did not enhance the effect of varicocelectomy.

Minutoli et al. [13] demonstrated that neuronal apoptosis inhibin factor and surviving expressions were significantly reduced following varicocele induction and polydeoxyribonucleotide, an agonist of adenosine A2A receptor, administration restored testicular function [13]. Several other studies detected increased germ cell apoptosis in rats with varicocele [21,22,27]. However, in another study, apoptosis was found to be decreased in germ cells in the testes of infertile men with varicocele as compared with normal men [28]. It was speculated that the fixation of testis in formaldehyde might have played a role in the different result. In the present study, cleaved caspase 3 expression was used to assess apoptotic activity and it was found that metformin reduced apoptotic activity in rats with varicocele, whereas no additional effect was observed when metformin was administered after varicocelectomy.

Metformin is commonly used in type 2 diabetes mellitus and polycystic ovarian disease as an insulin sensitizer [29]. Also, it is present in various tissues including myocardium, liver, pancreas, thyroid, adipose tissue, hypothalamus, pituitary, and male and female gonads [19,30,31]. It has been reported that metformin is mainly transported into cells by organic cation transporters as passive diffusion is limited [32]. Although the mechanism of action is not yet fully elucidated recent studies suggested that metformin acts through AMP-activated protein kinase (AMPK) pathway, inhibits the activity of the respiratory electron transport chain in mitochondria, induces epigenetic modifications which in part may explain long term effects and decreases oxidative stress and apoptotic activity [16,19, 33-35].

Male reproductive system utilizes all these metabolic pathways and is prone to be affected by metformin administration [20,36,37]. Metformin was found to stimulate lactate production which is important in the development of germ cells and show an anti-apoptotic effect in rat Sertoli cells [38]. It was also reported that metformin reduced the apoptotic cells and caspase-3 level in rat testis [20]. The findings of the present study are consistent with previous studies that metformin reduced apoptosis in testis with varicocele. Yan et al. [37] reported that metformin improved the semen parameters related to its effects on weight loss, increased testicular weight and reduced testicular cell apoptosis [37]. On the other hand, Tartarin et al. [36] reported metformin at concentration 10 times higher than therapeutic levels decreased testosterone secretion and the number of Sertoli cells in rats when it was administered during pregnancy [36]. Faure et al. [39] reduction in testicular weight and testosterone level were observed in 6-week-old chickens treated with metformin for 3 weeks [39].

Several groups demonstrated that post-operative administration of metformin can exert protective effects in male reproductive function in rat models [40]. Bosman et al. [41] demonstrated that infertile hyperinsulinaemic men could benefit from metformin treatment in combination with an enriched antioxidant diet [41]. Besides, metformin was reported to act as a protective compound when used in the media for cryopreservation of spermatozoa [30]. In conclusion, metformin reduces detrimental effects of varicocele, although no additional benefit is expected following varicocelectomy. Further studies are required to apply metformin for this indication in humans.

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Functional Selective D2 Ligands for the Treatment of Schizophrenia-Juniper Publishers

JUNIPER PUBLISHERS-OPEN ACCESS JOURNAL OF DRUG DESIGNING & DEVELOPMENT

Abstract

Functionally selective ligands (also known as biased ligands) of dopamine D2 receptors have been considered as not only valuable tools for dissecting the roles of D2-mediated G protein-dependent and independent signaling pathways, but also better antipsychotic drug candidates for neurological and psychiatric disorders including schizophrenia. Consequently, functionally selective D2R ligands have also been increasingly pursued by the biomedical community as promising antipsychotic therapeutics with improved efficacy and reduced side effects compared with unbiased ligands. This review will discuss the recent development in the discovery of functional selective D2R ligands Figure 1.

Introduction

Schizophrenia is a chronic and severe mental disorder characterized by abnormal social behavior and failure to understand reality [1]. Clinically, the disorder manifests with a large variety of symptoms that fall into three categories: positive, negative, and cognitive [2]. Schizophrenia affects about 1.1% of world wide population [3]. Although schizophrenia is not as common as other mental disorders such as anxiety disorder (18.1%) [4], depression (6.9%) [5], and bipolar disorder (2.6%) [6], the symptoms can be very disabling. Therefore, it is often associated with high levels of morbidity and mortality [7]. The average life expectancy of people with schizophrenia is ten to twenty-five years less than for the general population [8]. This is the result of increased physical health problems and a higher suicide rate (about 10%) [9,10].

Although scientists believe that a combination of genetics, environment, and altered brain chemistry and structure may play a role in the development of schizophrenia [11], the exact cause of this disorder is still unknown to the research community. Consequently, there is no cure for this disorder and treatments have been focusing on eliminating the symptoms of the disease. The primary treatment of schizophrenia is antipsychotic medications [12], often in combination with psychological and social supports. While the current FDA-approved antipsychotic drugs are able to reduce the positive symptoms of schizophrenia in about 7 to 14 days [13,14], they have limited efficacy with negative and/or cognitive symptoms [15,16].

Furthermore, antipsychotic medications can greatly lower the patients' life quality by inducing a wide range of motor, metabolic, cardiovascular, and emotional side effects which also lead to treatment noncompliance [14,17]. Therefore, it is of great necessity to develop novel pharmaco therapies which have better efficacies for treating all three clinical schizophrenia symptoms and possess a low profile for side effects.

With all currently FDA-approved antipsychotic drugs target primarily the dopamine D2 receptor (D2R) for their reaction [15-18], it is indicated that opposing dopamine signaling is central for alleviating psychotic symptoms with schizophrenia [19]. Clinical observations have revealed that schizophrenia-like symptoms occur in amphetamine abusers due to excessive dopamine release [20]. Also baseline dopamine levels and stimulated release of dopamine are found to be abnormal in mesolimbic systems of brains from schizophrenic patients [21]. All these evidences have put dopamine receptor, especially dopamine D2R at the center for the development of antipsychotic drug. Antagonists and partial agonists of D2R have been extensively pursued as antipsychotic therapeutics for the treatment of schizophrenia [22,23].

As a member in the big family of G protein-coupled receptors (GPCR), dopamine D2 receptor (D2R) is Gαi/o coupled whose activation inhibits CAMP production [24]. Antipsychotic drugs targeting D2R were originally identified as being able to bind to D2R and regulate CAMP synthesis [18]. Mounting evident from recent studies indicate that D2R signal not only via canonical pathway involving hetero trimeric large G protein, but also via noncanonical G protein-independent pathways with other signaling proteins including, most prominently, β -arrestins [2528]. Most antipsychotic drugs have been found to have both G protein-dependant and G protein-independent actions [28]. The process by which GPCR ligands, including D2R ligands, differentially modulate canonical and noncanonical signal transduction pathways is a phenomenon known as "functional selectivity" or "biased agonism" [29,30].

With functionally selective D2R ligands that can preferentially activate either canonical or noncanonical D2 signaling pathways [31,32], it is thus very clear that the D2R ligands with discrete functional selectivity profiles will be extremely useful for elucidating the key signal transduction pathways essential for both the therapeutic actions and the side effects of antipsychotic drugs [30]. And this understanding will in turn enable the design of better antipsychotic drug candidates, which can ultimately lead to safer and more effective therapies for schizophrenia patients. In this short review article, we will summarize the recent development in the discovery of functional selective D2R ligands for the treatment of schizophrenia.

Functional Selective D2RLigands

Aripiprizole

Aripiprazole (OPC-14597, 1), an FDA-approved atypical antipsychotic drug, was one of the first functionally selective D2R ligands identified [31,33,34]. It has an excellent side-effect profile presumed, in part, to be due to lack of typical D2R antagonist properties. Although aripiprazole was initially described as a partial D2R agonist, on the basis of assays performed in whole animals and isolated tissues [35-37], it was later demonstrated that aripiprazole could behave as a full agonist, a partial agonist, or an antagonist at D2R depending upon the signaling readout and cell type interrogated [28,31,33,38].

The study examined D2R binding properties of aripiprazole as well as the effects of the drug on three downstream D2R- mediated functional effectors including mitogen-activated protein kinase (MAPK) phosphorylation, potentiation of arachidonic acid (AA) release, and D2R internalization revealed that aripiprazole affects D2L-mediated signaling pathways in a differential manner [31]. In the study examining the properties of aripiprazole at D2 like auto receptors by monitoring the changes of dopamine synthesis in adult rat brain striatal minces incubated ex vivo, it was found that alteration of dopaminergic tone by depolarization affected the actions of aripiprazole on D2- like auto receptors [39].

The in vivo study aimed to investigate the effects of aripiprazole on the D2R downstream cAMP-PKA and Akt-GSK3 β signaling pathways suggested that aripiprazole had differential effects on the cAMP-PKA and Akt-GSK3 β signaling pathways in the brain areas [40]. Additional studies examined the activity of aripiprazole in D2R-mediated heterologous sensitization of adenylyl cyclase and cell-based dynamic mass redistribution (DMR). Aripiprazole displayed a unique functional profile for modulation of G proteins, being a partial agonist for Gαi/o and a robust antagonist for G β γ signaling. Additionally, aripiprazole was a weak partial agonist for both heterologous sensitization and dynamic mass redistribution [41].

UNC9975 (2), UNC0006 (3) and UNC9994 (4)

Through a robust diversity-oriented multi-dimensional modification ofthe scaffold represented by aripiprazole (1), Three β -arrestin-biased D2R ligands including UNC9975 (2), UNC0006 (3), and UNC9994 (4) were reported as the unprecedented β -arrestin-biased ligands for a Gi-coupled G protein-coupled receptor (GPCR) [42]. All three D2R ligands were simultaneously antagonists of Gi-regulated CAMP production and partial agonists for D2R/β-arrestin-2 interactions. Importantly, UNC9975 displayed potent antipsychotic-like activity without inducing motoric side effects in inbred C57BL/6 mice in vivo. Genetic deletion of β -arrestin-2 simultaneously attenuated the antipsychotic actions of UNC9975 and transformed it into a typical antipsychotic drug with a high propensity to induce catalepsy.

Similarly, the antipsychotic-like activity displayed by UNC9994, an extremely β -arrestin-biased D2R agonist, in wild- type mice was completely abolished in β -arrestin-2 knockout mice. These results suggest that β -arrestin signaling and recruitment can be simultaneously a significant contributor to antipsychotic efficacy and protective against motoric side effects [42]. Follow-up comprehensive structure-functional selectivity relationship studies (SFSR) focused on four regions of aripiprazole scaffold (e.g. left hand side phenyl region, middle amino region, central linker region, and right hand side bicyclic aromatic region) resulted in more β -arrestin biased D2R agonists [43].

This combined medicinal chemistry and pharmacological profiling approach also provided the biomedical community a successful proof-of-concept for how functionally selective ligands can be discovered. The study designed to test the effectiveness of UNC9975 or UNC9994 on schizophrenia-like behaviors in phencyclidine treated or NR1-knockdown hypoglutamatergic mice showed that the UNC compounds reduced hyper locomotion in the open field, restored PPI, improved novel object recognition memory, partially normalized social behavior, decreased conditioned avoidance responding, and elicit a much lower level of catalepsy than haloperidol [44]. These preclinical results suggest that exploitation of functional selectivity may provide unique opportunities to develop drugs with fewer side effects, greater therapeutic selectivity, and enhanced efficacy for treating schizophrenia and related conditions than medications that are currently available.

Cariprizine (5) and analogs (Compounds 6 And 7)

Cariprizine(5) is an atypical antipsychotic recently approve by FDA for the treatment of schizophrenia and bipolar mania [45]. It acts primarily as a partial agonist for D2R and D3R [46] with higher selectivity for D3R [46,47]. The structure-functional selectivity relationship (SFSR) studies of cariprazine scaffold carried out by Shonberg and colleagues at Monash University was focused on three main portions of the lead compound: the tertiary amine containing "head group", the cyclohexylene "spacer" group, and the tert-butyl carbamate "tail group" [48].

Similar to the SFSR studies of aripiprazole analogs, to assess G protein-related signaling, the compounds were profiled in the D2 CAMP accumulation assay, whereas β -arrestin signaling was evaluated by measuring phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2). In this testing paradigm, cariprazine (5) displayed a 230-fold bias toward the cAMP pathway compared with dopamine. Interestingly, while all cariprazine derivatives disclosed in this letter showed a bias toward the G protein signaling pathway (6), subtle changes of the D2 unbiased partial agonist, a structurally related aryl piperazine reported by Tschammer [49], led to analogues that displayed a strong bias toward β -arrestin signaling such as compound 7. By combining the medicinal chemistry efforts with novel analytical pharmacology methods [50], it was discovered that the nature of the head group, the composition of the tail group, and the orientation, length, and flexibility of the spacer were all important factors for the control of functional selectivity at the D2R [48].

Functional selective D2R ligands with privileged structures (compound 8)

Another comprehensive structure activity relationship (SAR) studies carried out by Szabo and colleagues at Monash University also led to the discovery of novel functional selective D2R ligands [51]. They investigated the determinants of efficacy, affinity, and bias for three privileged structures for the D2R, exploring changes to linker length and incorporation of a heterocyclic unit. After profiling the newly synthesized compounds in two signaling assays (CAMP and pERK1/2), they were able to identify and quantify determinants of functional selectivity at the D2R. The results from combined medicinal chemistry and pharmacological profiling approach revealed that: 1) substitution on the phenylpiperazine privileged structures (2-methoxy vs 2,3-dichloro) influenced bias when the thienopyridine heterocycle was absent; and 2) upon inclusion of the thienopyridine unit, the substitution pattern (4,6-dimethyl vs 5-chloro-6-methoxy-4-methyl) had a significant effect on bias that overruled the effect of the phenylpiperazine substitution pattern [51]. This latter observation could be reconciled with an extended binding mode for these compounds, whereby the interaction of the heterocycle with a secondary binding pocket may bring functional selectivity to the parent compounds. The resulted novel D2R partial agonists, 8 and 9, display a similar affinity for the D2R as aripiprazole but exhibit distinct functional selectivity profiles, which made them useful tools to explore the contribution of functional selectivity to antipsychotic efficacy.

Functional selective D2R/D3R partial agonists

Dopamine D2R and D3R are known as valuable targets for the treatment of neurological and psychiatric disorders including schizophrenia [52-54]. Hiller and colleagues evaluated a series of newly synthesized compounds for their ability to differentially activate distinct signaling pathways [55].

Measurement of D2L- and D2S-mediated [35S] GTPyS incorporation in the presence of coexpressed Gao and Gai subunits showed significantly biased receptor activation for several test compounds [55]. A follow-up study from the same group using the same evaluation methods yielded the most striking functionally selective D2R ligand, carbaldoxime 8b (9, Gaol, pEC50 = 8.87, Emax = 65%; Gai2, pEC50 = 6.63, Emax=27%) [56]. It was also indicated in the study that 1,4-disubstituted aromatic piperazines (1,4-DAPs) behaved as antagonists for β -arrestin-2 recruitment, implying significant ligand bias for G-protein activation over β -arrestin-2 recruitment at D2R. Regiochemistry and the nature of functional groups attached to the pyrazolo [1,5-a]pyridine moiety strongly influence ligand efficacy and selectivity between D2R and D3R activation [56].

Other functional selective D2 ligands

Intensive structural exploration on aripiprazole scaffold engendered UNC2438 (10) which was found to be a G-protein biased compounds [57]. Further structure-functional selectivity relationship studies (SFSR) on UNC2438 focused on the right hand side benzothiazole moiety and the left hand side phenylpiperazine moiety furnished a few additional G-protein biased compounds which were partial agonists in D2R Gio- mediated CAMP inhibition assay and simultaneously inactive in D2R-mediated β -arrestin-2 recruitment assay [57].

Most recently, a tailored virtual library with close to 13,000 compounds bearing 2,3-dichlorophenylpiperazine, a privileged orthosteric scaffold, connected to diverse chemical moieties via a linker was docked to the D2R model [58]. Eighteen top-ranked compounds that occupied both the orthosteric and allosteric site were synthesized, leading to the discovery of 16 partial agonists. While a majority of the ligands had comparable maximum effects in the G protein and β -arrestin recruitment assays, some displayed preference for a single pathway. In particular, compound 11 stimulated β -arrestin recruitment (EC50 = 320 nM, Emax = 16%) but had no detectable G protein signaling.

Conclusion

The growing realization of the complexity of G protein coupled receptor (GPCR) mediated signal transduction pathways, specifically D2R mediated signaling pathways, has provided a theoretical framework for the development of functionally selective or biased ligands. Several studies have demonstrated that agonists differ in their ability to activate various pathways. Notably, blockade of β arrest in recruitment was found to be a shared property of antipsychotics that exhibit either antagonist (e.g., haloperidol), or partial agonist (e.g., aripiprazole) activity through Gai/o-CAMP pathways [28]. In contrast, a study with analogs of the novel antipsychotic aripiprazole suggested that D2 ligands with Gai/o antagonist and β -arrestin agonist activity may have antipsychotic behavioral activity with reduced extra pyramidal side effects in a mouse model [3]. While there are still a lot of questions to be answered in this field, heightened awareness of the potential benefit of pathway biased D2R ligands has inspired scientists in this area develop more functionally selective D2R ligands as better antipsychotic therapies for schizophrenia.

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juniperpublisherscasestudies · 3 years ago

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Juniper Publishers-Open Access Journal of Case Studies

A Case Study on Birth Experience

Authored by Ayman Aboda

Abstract

Background: Normal consciousness may be profoundly changed during labour. Access to heightened states of personal and existential awareness may be part of the uninhibited ritual of natural childbirth.

Aim: Validate the possibility of heightened awareness and transcendence that can occur beyond the province of normal human experience. Peek experiences may bring life changing realizations of deep universal connection and personal insight.

Findings: Breakthrough experiences may occur in any state of intense physical focus, including the mindfulness of supported birth practices.

Discussion: The perspective reiterates the importance of rational, individualized, woman-centred care in birth.

Conclusion: The environment of birth, the safety and support of known and trusted care givers can allow birth events to unfold with the least possible intrusion. A hitherto under-recognized sequalae for such freedom may be the possibility of connecting to a state of expanded awareness that can bring profound unveiling of inner being and self-acceptance.

Keywords: Normal consciousness; Natural childbirth; Woman's emotional experience; Bleeding; Fearfulness; Birth experience; Acute medical resuscitation, Neurosurgeon

Statement of Significance

Problem

Constrictive models of care during birth.

What is already known

Current institutionalized models are driven by risk and litigation. Success in mitigating such harms has been tempered by spiralling costs of intervention and more insidiously, a diminution of the birth experience.

What this paper adds

The rationalization of appropriate care. The importance of choice and the understanding that birth can yield of itself, a glimpse into the extraordinary, an experience of wonder and life changing self-awareness that can be truly transformative for the mother and for all those with whom she shares her journey.

Go to

Pushed to the Limit - Reclaiming the Ecstasy of Birth

“I remember when my world changed forever. I experienced something miraculous when I gave birth, I gave birth to myself as a mother. During labour, I noticed the world around me change. The lights seemed dimmer and there was a silence in the room. I was conscious but it felt different. There was an incredible sense of calm. I could sense everything, the bed, the room, my breath, and heartbeat, my thoughts and feelings. Time stood still. I was no longer connected to the room. I was distant in a place I had never been before. I was totally removed from everything. There was a sense of floating without boundaries. It was so calm, peaceful. I remember looking down as I hovered over my body, watching myself from above, as if I were two separate beings. I felt so loved. Fearless. I have never felt like this before, the beauty, the purity and bliss. A realisation of my existence came. It was as if I had gained clarity and the answer to life's many questions. Everything was exposed in its truest form. I knew why I was here and what I was born to do. I was here to create.”

GS – personal birth story.

What’s it like?

Long before the infamy of Covid 19, a philosopher once asked what it would be like to be a Bat? [1] Would it think as we do? Would it experience the world in the same way? Of course, we imagine that it would, but then all we’re really doing is putting ourselves within, thinking of it as just a smaller version of us; something that sees as we do, hears in the same way – albeit with bigger ears, and otherwise makes sense of its perceptions with the same quality and perspective of mind. But no one can really say for sure – which was in fact the whole point of the question: to remind us that all we can ever truly know is what it’s like to be us. And what is that you might then ask. Well, that’s easy, it’s the awareness we have of living, of being here, experiencing the world around us and knowing where we are within it. Now whilst this may or may not be true for other creatures - including bats, the outward-looking, body-centred perspective through which we frame our experience of living seems so much a given norm, that it’s hard to imagine there could be any other way of doing things. But is there?

Looking beyond the veil

In his book, “Life after Life”, Raymond Moody described a near-death experience which was noted following an acute medical resuscitation [2]. The survivor told his rescuers that whilst they’d been busy trying to save him, he’d been looking down as things occurred, watching the entire scene unfold from a point that was from somewhere outside his body. On the one hand he knew that this was something that shouldn’t normally happen and yet it had seemed so undeniably real that he couldn’t believe it hadn’t. More recently, American neurosurgeon Eban Alexander reported a similar sensorial shift with translocation of living awareness away from the body at a time when deep, septic coma had stopped all measurable brain activity [3].

These and other accounts suggest that the seat of consciousness may not be as firmly anchored as previously imagined, and that the usual, body-centred perspective may be just one of many possibilities available to us. But of course, we know this already for in our dreams each night, most of us experience vast multiplicities of non-ordinary awareness or altered states of being that we simply take for granted as flights of fantasy. In his book, “Journeys out of the Body,” Robert Monroe described specific techniques to intentionally induce similar states of transpersonal, or Out-of-Body Experience (OBE) in daytime too, where consciousness could exist replete and fully visceral despite separation from the physical body [4]. Cognitive awareness of self and surroundings remain corporally vital, with the experience most often described as a heightened or more splendid state of normal which could at times lead to an unprecedented feeling of bliss or profound belonging as if having become intimately connected to some greater universal presence or unconditional ease.

Not surprisingly, Out of Body Experiences can transform lives, and indeed they do. For the prophet Elija, the apostle Paul, Saint Francis of Assisi, the Buddha, and the modern spiritual teacher Ekhart Tolle, this was powerfully so. Sadly however, such revelations seem sparsely scattered, contained if lucky, to the zeal of a few determined practitioners or else the fervour fuelled of religious rapture or tribal ceremony such as the dreamtime of indigenous Ngangkari or shamanic ritual or more illicitly, from the psychedelic haze of contemporary drug culture. Without the agency of such provocateurs, one might reasonably wonder if the phenomenon was indeed meant to happen in normal life. Afterall, nature tends only to preserve or promulgate those behaviours that best suit the ability to survive - including the way we perceive the world. The paucity of OBE’s, notwithstanding their reputed glimpse of wonder, may simply reflect that they are less advantageous at keeping us alive - unless of course something changes that makes them more able to do so.

Holocaust survivor Viktor Frankl described looking down at his body during the terror of war and internment [5]. He thus felt distanced from the inhumanity and outrage of the horrors inflicted upon him and was somehow more able to survive. To withdraw from the immediacy and acuity of the senses can help to endure, to sustain trials of physical hardship and duress. Similarly, to quell the plethora of the senses, to focus intently may optimize performance in peek states and zones of intense concentration allowing an almost trance like state of deep attention for what needs to be done. In such states, the extraordinary can become possible and feelings of deep, transpersonal connection and grounding can arise.

Pushing to the limits –the energy of childbirth

“In the most intense hours of labour, I became mindless, floating in boundless space between contractions. All thoughts receded. My mind plummeted into an immense silence bathed in love and well-being. I felt a oneness with all mothers who had ever birthed” [6].

A woman's emotional experience during labour may show common themes, beginning with excitement and a need to feel safe and supported as her contractions develop which means she can then focus her energy on getting through things, one surge at a time [7]. Her world then narrows as concentration deepens and she may become less aware of things around her, moving into a ‘zone’ of timelessness, of dissociation or disconnection with the rest of the world. In this phase, perhaps 10% of women may experience states of altered awareness, including fully-fledged OBE’s where the boundaries of self and ordinary reality become less defined and deeper, more subtle levels of creativity and spiritual encounter can occur. These feelings then transition and become more grounded as an urge to push strengthens and a reconnection with the present emerges, often bringing a realization of awe and amazement as the power of their bodies moves them irresistibly towards birth [8].

modelling

“In achieving the safety of childbirth our society may have lost more than it has gained.” [9]

Birth however is not always perfect. Whilst it is a natural process, left to itself, it may not always lead towards a desired or safe ending. There may be pain, unprecedented in its intensity; bleeding, a fearfulness of what lies ahead, of what remains unknown or unexpected. There may be escalating risk or concern that must be managed. Models of care have thus evolved to mitigate, to wrestle control from such uncertainty, to bring order to chaos, to reign-in the freedoms of nature’s way. And so, we change. We change things, and more sadly so, we change ourselves. We stop seeing women as mothers or as mothers-to-be; they become patients. We take them from home, from community and on-country, and admit them to hospital to be cared for, to be monitored, to be made right. Labour becomes a diagnosis, an illness, a condition that must be treated and fixed. Natural rhythms are ignored and give way to ever more intrusive cascades of intervention.

Without doubt, neonatal and maternal outcomes have improved, but there comes too a growing apprehension of cost, of over-service, and more distressingly, an ever-widening wound of visceral and emotional discontent that follows thereafter. What began in good faith, what began because we genuinely care, because we wanted to help, has become a mandate. We now do what we do because we feel we have to. We feel we must. We believe it’s best. But is it always so?

By institutionalizing the birth experience, we can diminish a woman’s ability to participate, to help nurture the power and flow of her body to progress naturally and spontaneously. More subtly, by controlling her experience so arduously, we hide from her the opportunity to encounter an intimate, perhaps sacred awakening of deeper self that might otherwise have occurred. We thus sterilise the possibility of transience, of enchantment. We diminish the extraordinary to something best forgotten. We brush it aside as vagrant, a symptom of momentary dysfunction, or the rekindling of aberrant memory in the fever of fatigue [10].

Pushing back - reclaiming safe passage

Birth is of itself complete, it lacks nothing to make it more so. We have tried to make it better and of course in many ways we have, but at what cost? And for such gains won, how much has been lost? In our desire to make it fit, to conform to modern standards, there may be much that we have taken, that we have forsaken. We may have stolen from it something subtle, an opportunity to transcend normal living and experience an intimate revelation of profound connection and wonder.

The awareness we have of ourselves in the physical world is miraculous, a perspective made possible by the wondrous workings of what makes us human. Occasionally however, states of expanded, other-worldly consciousness can occur, where glimpses of a far-from-normal reality can pervade our senses with life changing ardour. When we consider the impact that such transformative experiences can bring, we may well grieve for their paucity.

In Australia, over 300 000 women give birth annually. 1 in 10 of these may experience feelings of altered consciousness which for some, may lead to an encounter of unprecedented personal realization and bliss. Imagine the impact that such life-changing experiences could bring. Imagine a birthing space where the unfolding of such deep ritual was nurtured, where we protect and gently support each mother to follow if she desires, the natural rhythms of her body. Where we gave freedom to experience the power of birth, and, if it should happen, the revelation of divine inner being that may enrich her life thereafter. Imagine what this would bring for her little one as she bonds and for those with whom her life is shared. Imagine what this would do to her world. To yours. To ours. It’s not just a want, it’s a rite worth wanting, a rite worth reclaiming. All we need do, is just let it happen. I think we can.

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juniperpublishersoceanography · 3 years ago

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Prospects of Rare Actinomycetes for the Production of Newer Antibiotics- Juniper Publishers

Abstract

Rare actinomycetes are the genera of actinomycetes other than Streptomycetes found in less expored environment. Some of the actinomycetes genera such as Sinomonas, Nocardia, Micromonospora, Actip lanes, Pseudonocardia, Actinomadura, Micrbobispora are known as the novel species. Rare actinomycetes have been found to produce extremely useful secondary metabolites. They have the good antagonistic activity against the various human pathogens. Hence, it is believed to give a promising output of commercially important product for pharmaceutical industries.

Keywords: Rare actinomycetes; Novel species; Antagonistic activity; Secondary metabolites; Antibiotics

Introduction

Actinomycetes are widely spread in nature, which are recognized to produce novel secondary metabolites. Among the overall genera in nature, actinomycetes by itself produce 70-80% of the existing antibiotics. In that, Streptomycetes found to produce 74% of antibiotics, which possess altogether 7,600 compounds lead of therapeutic agents like streptomycin, chloramphenicol, tetracycline, macrolides respectively. Production of novel drugs faces many problems, due to the rediscovery ofthe known secondary metabolites. It has driven the industrial attention towards the rare actinomycetes. Actinomycetes from the unexplored habitats seem to possess the potential antimicrobial activities against the human pathogens. The critical situation faced by various pathogens from hospitals and industries have lead to the demand for new drugs and chemical compounds in pharmacology. Hence, poorly explored area to be explored much for the novelty in the screening of rare actinomycetes. Actinomycetes are capable to grow in extreme environments like hot and dry deserts, hyper salinity, hay, sea water/sea muds, mangrove sediments, caves etc. Researchers are now focusing on the isolation of rare actinomycetes which are non- streptomyces. Genera such as Sinomonas humi sp. [1], Salinispora sp., Micromonospora, Actinoplane, Nocardia caishiienris and Pseudonocardia Carboxydivorans [2], Thermomonospora sp., Saccaropolyspora sp., Corynebacterium sp. [3] respectively are isolated as the novel stains.

Habitats of Rare Actinomycetes

Diversity of actinomycetes depends on the environmental microflora. Takahashi et al. describes that the diverse actinomy cetes found taxonomically and physiologically at desert soil [4]. He could isolate various genus like Microbispora, Nocardia, Microtetraspora/ Actinomadura, Amycolatopsis respectively from the Moava desert, California. Hamedi et al. represented novel species like Nocardia arvandica isolated from the sandy soil [5]. Nocardiopsis strains are found to grow in alkaline soils with high salt concentration at moderate temperature (37 °C). Nakaew et al. described that the genus Micromonospora isolated from Thai cave soil with low nutrient and high humidity, encourages the production of novel antibiotics and hydrolytic enzymes [6]. Phatup cave Forest park and Phanangkhoi cave in north Thailand were studied for the development of new bioactive compounds from rare actinomycetes. Endophytic actinomycetes are studied from the medicinal plants of Tropical rain forest in Xishuangbanna, China. Qin et al. explored the entophytic environment with the novel species like Saccaropolyspora, Dietzia, Blastococcus, Dactylosporangium, Promicromonospora, Oerskovia, Actinocorallia and Jiangella respectively [7].

Several interesting unusual habitats like the sediments of lakes [8], fungal cultivar [9] and ant workers produces antimicrobial products with the symbiotic association of actinomycete bacteria [10], Mangrove sediments [11], deep sea biodiversity [12], Marine sedimentation [13] respectively has reported the novel species of actinomycetes, with the pharmaceutical potent.

Antimicrobial Activity

Marine actinomycetes are found to have very good potential for the production of novel bioactive metabolites [14]. Secondary metabolites produced by the rare actinomycetes have potential antibacterial activity [15] has reported the Salinospora species from Fijian marine sponge, which showed the activity against the Methicillin-resistant Staphylococcus aureus stains. Qin et al. also reported that the species of rare actinomycetes like endophytic Pseudonocardia alni and Pseudonocardia zijingensis also showed significant antagonistic activity against the Methicillin-resistant Staphylococcus aureus stains [7]. Genus Micromonospora produces novel compounds like antraquinones and lupinacidins, which showed the anti-tumor activity. Tanvir et al. also found that the Pseudonocardia carboxydivorans exhibiting the anti-tumor activity [2].

Conclusion

Exploring the untapped area leads to the isolation of novel rare genera of actinomycetes with new bioactive compounds. Proliferation of new genera leads to the production of neobioactive compounds. Rare actinomycetes had increased the interest in tracking the microbial groups in the drug discovery process.

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annieboltonworld · 3 years ago

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Juniper Publishers-Open Access Journal of Environmental Sciences & Natural Resources

Carbon Quantum Dots In Environmental Remediation

Authored by Zahra Ramezani

Abstract

Carbon quantum dots (CQD), is highly stable, biocompatible, and low toxic fluorescence nonomaterial that extensively used in different scientific disciplines such as design and construction of low-cost chemical and biological sensors, cell imaging, clinical diagnosing, and drug loading. Due to their optoelectronic properties, they have recently used in remediation studies as an alternative to or mixed with metal semiconductors. Having used CQD, an economic and green technique in environmental pollution remediation is introduced. Remediation happens through the ability of CQD composites in adsorption of pollutants or using its photo catalytic action. Herein, some recent applications in the environmental pollutant remediation are reviewed.

Introduction

CQDs are a new type of carbon nanomaterial accidentally found in 2004 through purification of single-wall carbon nano tubes [1]. They have attracted much scientific attention since they are stable photoluminescence particles with high chemical stability, low toxicity, and biocompatible as well as having optoelectronic properties. They are produced by different chemical or natural carbon rich precursors in one pot process by different heating methods [1-4]. The CQDs properties have tuned by surface modification through different synthetic protocols and using different chemical reagents [5] for a vast variety of applications since 2004. CQDs have strong and stable luminescence, and have been used in chemical sensors, optoelectronics [6-8] bacterial detection [9], cancer diagnosis [10], cell imaging [11] and drug loading [12].

Exposure of CQDs with photons of energy equal or higher than its band gap leads to the transfer of the electron from the valence band to the conduction band, producing an electron-hole. Both electron and hole on the surface of the CQDs gives it the ability to act as both electron donor and acceptor, and promote oxidation-reduction on the surface of the dots [13]. Doping CQD with dozens of elements like N, P, and S have induced a shift in the photoluminescence wavelength, and suggest its applications as an efficient catalyst. Photo catalytic degradation of organic pollutions and microorganism is extensively reported in the literature using semiconductors [13].The high photo activity of the catalyst has a vital role in the oxidation or reduction of the pollutants. Photo catalytic activity of CQDs improved by incorporating elements such as nitrogen on the surface, and preparation of a composite with other semiconductors such as TiO2. Pollutant remediation using CQDs is mainly due to the photo catalytic properties. But adsorption of the pollutants on the surface of CQDs composites is another strategy has rarely been used up to now. However, the application of CQDs in the pollutant remediation is briefly discussed and listed. Photocatalytic Degradation of Pollutants is an Title CQDs under photon irradiation generate electron-hole and acts as the visible light photo catalyst in environmental remediation and energy transfer reactions. A few reports on the application of CQDs for adsorption of environmental pollutants are available in the literature. Some recent application of CQDs, doped CQDs, and their composites with other nano particles, in environmental remediation, is reported in (Table 1) and discussed. Photo catalytic conversion of CO2 to organic acids by nitrogen doped CQD (NCQDs) with visible light irradiation was more efficient than colloidal TiO2 under UV radiations [5]. Martin et al [13] also synthesized nitrogen doped CQD by hydrothermal irradiation using glycerol as the carbon source and 4,7,10 trioxa-1,13- tridecanediamine for nitrogen doping. They prepared NCQD/ TiO2 nano composite and showed that photo catalytic activity of nano composite for methylene blue and NO remediation is higher than those for TiO2. Super paramagnetic nitrogen doped CQD /magnetite nano composites (Fe3O4@NCQD) [14,15] were used for removal of methyl blue from polluted water samples. They used lemon juice as a green carbon precursor and ethylene amine as the nitrogen source for CQD surface functionalization.

As-prepared Fe3O4@NCQD adsorbs 90.84% methyl blue from aqueous solutions in 20 min. Particles were separated from the solution by a magnet, methyl blue has been desorbed by hydrochloric acid, and the recovered particles were used five times without any considerable changes in the removal efficiency. CQD/nitrogen-doped ZnO (CQD/N-ZnO) composite was prepared and used for photo catalytic degradation of three commercial dyes, malachite green, methylene blue and fluoresce in under daylight irradiation. The composite removes all three dyes within 30-45 minutes [16]. CQDs-TiO2nanosheet (CQDs- TNS) composites were prepared and used in photo catalytic degradation of rhodamine B under visible light irradiation [17].

It was reported that photo catalytic activity of CQDs-TNS was higher than CQDs/TiO2 and pure TNS. Catalytic H2 production using highly crystalline CQDs on 2D C3N4nanosheets was reported [18]. Hydrogen peroxide produced during the reaction promotes bisphenol a removal. Excellent photo catalytic activity was observed for ternary mixture of CQDs/Ag/Ag2O [19]. The ternary photo catalyst removed methylene blue and Rhodamine B from aqueous solution. Composite of CQDs with g-C3N4nanosheet was also reported as an excellent photo catalyst for the degradation of rhodamine B and tetracycline hydrochloride (TC-HCl) under visible light irradiation [20]. Tetracycline mineralization by the composite of Ag+-CDs-Bi2WO6 [21] via photo catalytic reactions under visible light is also reported. The Ag+-CDs-Bi2WO6 has excellent stability even when recycled and reused for several times. Fe (III)-functionalized carbon dots (Fe(III)-CQDs) was used for remediation of hydrogen peroxide as well as olefin hydrogenation with high selectivity [22]. A green approach applied to the synthesis of La/Cu/Zr/CQDs tri metallic nano composites as both adsorptive and catalytic agent for pollutant remediation [23]. It has been observed that 96% ampicillin antibiotic and 86% of malachite green were degraded in 4 h. The prepared Bi2O3/ CQDs photo catalysts [24] showed the best photo catalytic activity in rhodamine B elimination. A new CQDs/ Bi2WO6 were applied in the remediation of methyl orange and bisphenol A in aqueous solution [25]. A novel ternary photo catalyst of single atom-dispersed silver and carbon quantum dots co-loaded with ultrathin g-C3N4 (Ag-CQDs- gC3N4) was synthesized [26]. Environment-Friendly CQDs/ ZnFe2O4 photo catalyst was synthesized and introduced as a biocompatible catalyst for NO removal in the atmosphere [27]. The catalyst has low cytotoxicity and is a good candidate for air purification. Application of CQDs was extended to the removal of microorganism from aqueous solution. Recently, multiwall carbon nano tube fiber incorporated CQDs (MWCNT-F/CQDs) composite has been proved as highly efficient material for bacterial removal from aqueous solution and inhibition of their activity [28]. In this study, the inhibitory rates for E. coli were 94.21% on the MWCNT filter surfaces coated with 0.2 mg CQDs.

Conclusion

To sum up, CQDs are introduced recently as the visible light photo catalyst for environmental remediation. The catalytic activity of CQDs increases by metals doping or making composites with the other semiconductor. Adsorption ability of CQDs for environmental pollutants are not well investigated. Another outstanding action of CQDs is in bacterial growth inhibition and removal from aqueous solution. Overall, CQDs is a green and biocompatible material for treatment and purification of water and atmosphere.

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juniperpublishers-agriculture · 3 years ago

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Impact of Cover-Crop Residuals on Soil Carbon Sequestration and Respiration- Juniper publishers

TGlobal policies encourage to lower greenhouse gas emissions in order to maintain climate change under the limit of +2°C at the horizon 2100. An important part of these gases are emitted from croplands and farms [1]. To reduce the environmental impact of croplands, diverse techniques and practices have been widely used by farmers, based on conservation agriculture (simplified cultivation techniques, cover-cropping, agroforestry, etc.). The use of these techniques has been adopted freely, according to the good will of farmers. Scientists have broadly studied these crop management practices in order to evaluate their impact on climate change [2–4]. Actual assessment of carbon emissions and storage capacities of croplands under such crop management practices had helped us to discriminate the practices useful for carbon accumulation. No-tillage has an important role to play in agriculture, mainly because of the great impact on soil bulk density and ease of crop germination. However, it is now well known and admitted that no-till have no significant impact alone on soil carbon storage capacities over the entire soil profile [5]. Cover-cropping is also an interesting and promising management practice to consider when accounting for climate resilient agroecosystems, soil carbon sequestration [6] and ecosystem services [7]. This practice can have very contrasted impacts on soil and the agroecosystem depending on sowing and destruction period, species used, for how long and how the residues are managed. Indeed, cover-cropping leads to improved biomass production and undoubtedly, to more crop residues. The impact of crop residues on soil carbon have been widely studied [8–10], but their impact on soil respiration still needs to be clarified. How do cover crop residues respiration change over the crop season? Soil respiration was measured with an infrared portable gas analyzer together with a soil respiration chamber (EGM4 and SRC1, PP Systems, Amesbury, USA). The study site was located in Southwest France (N 43° 24’ 38.057’’, E 0° 17’ 17.612’’, alt= 266 m) on a soil defined as a Stagnic Luvisol according to the World Reference Base for Soil Resource [11]. No-till and cover-cropping have been implemented for 20 years, which improved soil organic carbon content of 48.8% compared to conventional agricultural system. The cover crop was mainly composed of faba bean (Vicia faba), oat (Avena sativa) and triticale (×Triticosecale) for the last 4 years. We measured soil respiration with and without residues and for residues alone. We observed an increase of soil residues respiration over the season as well as of values dispersion (Figure 1). Very low level of respiration rate was observed from the 30th of June to the 10th of September, even if few points had respiration values in the range of values generally observed for soil respiration for temperate ecosystems [12]. But significant higher values of respiration were observed on the 29th of September and October (p value < 0.05). The increase in soil respiration across the season was attributed to the maturation of crop residues and their gradual transformation from fresh organic matter to labile and dissolved organic matter, more easily degradable for microorganisms. It then appeared that the degradation process of cover crops passed through different phases; slow degradation until the senescence of the cash crop (here maize), then degradation inducing significant respiration. It seems that maize senescence leaded to favorable conditions for cover crop residuals degradation. Usually, when maize enters senescence, farmers stop irrigation to let maize dry before harvesting. Cover crop residuals could reach their optimum degradation rate with optimum both soil moisture and temperature promoting respiration of residuals in this particular time period. A second hypothesis is that maize plants senescence could imply microorganisms within maize rhizosphere to look for other sustainable carbon source when maize roots stop to diffuse exudates in soil [13,14]. These microorganisms could change of substrate when maize exudates stop and move from exudates to surface carbon.

Conclusion

TCover-crops constitutes a good solution to improve soil carbon content sequestration, both by increasing biological activities notably through biomass accumulation and exudation, and abiotic impact on cropland (temperature and humidity control). However, the production of supplementary biomass induces supplementary carbon fluxes from the agroecosystems that needs to be taken into account when assessing carbon footprint of croplands.

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omc-juniperpublishers · 4 years ago

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Synthesis and Characterization of Low-Cost Activated Carbons for Pollutants Removal from Automotive Emissions-JuniperPublishers

Journal of Chemistry-JuniperPublishers

Abstract

Air purification is one of the most widely known environmental applications of activated carbons. In order to guarantee the successful removal of contaminants and pollutants on activated carbons, the development of new adsorbents has been increasing in the last few years. This paper presents a systematic study for cleaning vehicles emissions of CO, SO2, NO2 and H2S using the process of physical adsorption on novel adsorbents obtained from tropical biomasses. Use of this simple method is a valuable alternative to meet emission standards in Developing Countries. It is known that the agricultural wastes studied here are a feasible alternative for granular activated carbons preparation for pollutants removal during engines operation, approaching its efficiency to the commercial Catalytic Converters.

Keywords: Combustion gases purification; Activated carbons; Adsorption and adsorbents; Pollutants removal

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Introduction

“Quality Can Be Planned.”-Joseph Juran

Wastes cannot be introduced to the environment in unlimited amounts, especially in case of air pollutants. Different measures have been taken to limit the pollution emission. These are e.g.: the elimination of technological processes generating a lot of waste, introduction of new technologies which minimize the contamination, etc. If it is not possible to reduce the emissions, the waste gas must be purified [1,2]. Nowadays, the economic conditions of Developing Countries don’t allow that all individuals own a new automotive. It is necessary to develop alternatives to reduce the negative environmental impact associated with obsolete engines operation. The best way to address it is by reducing certain exhaust gas components during fuel combustion. The answer therefore is to look at vehicles as an integral whole to identify which solutions would be more feasible. Taking this holistic approach to vehicle improvement as a basis, three main exhaust emission control strategies can be defined:

a.Reduction of fuel consumption;

b.Exhaust gas treatment, and

c.Performance monitoring.

From these three alternatives the second one is currently the more effective for air quality improvement. The main gas treatment currently used is the Catalytic Converter, typically comprises of an expensive porous ceramic substrate with large surface area [3]. Unfortunately some users in Central America and the Caribbe an Countries tend to remove the Catalytic Converter from the vehicles to get better power loads. Over the last decade, the study of combustion gas treatment has been focused on more sophisticated Catalytic Converters. Consequently, the study of other alternatives for exhaust gas purification is important. There are a few methods to purify harmful combustion gases such as physical adsorption [4,5], chemical absorption [6], catalytic methods, etc. [7,8]. It is necessary then to select a suitable method to purify harmful gas for Developing Countries. Besides, standards for vehicles become more mandatory day to day. The more feasible alternative would be the development of customized activated carbons filters for the betterment of the environment. This can be accomplished by reducing the emissions that contribute to smog and acid rains [9].

Activated carbons can be obtained from different precursors, with benefits to the environment [10-12]. Due to its chemical composition, forest biomasses are valuable sources in the synthesis of adsorbents materials. Several examples of activated carbons preparation can be found in the open literature [13,14]. They have been used among others in the purification of pollutants gases such as carbon dioxide, sulfur dioxide, hydrogen sulfide, nitrogen oxides and mercury [15-17]. Taking into account this background, the main objectives of this work can be summarized as follows:

I.Study the feasibility of some agricultural wastes as raw material for activated carbons production with high specific surface area, high mechanical resistance and wide availability.

II. Definition of the best experimental conditions for “chemical activation” with H3PO4 such as “physical activation” with steam water for each precursor.

III. Study of the elimination of pollutant gases in vehicles engines with filters of the adsorbents produced.

IV. Proposal of a methodology for filters evaluation in the removal of undesirable pollutants (CO, SO2, NO2 and H2S) during engines operation.

The practical aspects addressed in this research cover the broad spectrum of applications for air cleaning. Better engines performances can be obtained with an adsorption technique of activated carbons, through an extremely economic method.

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Materials and Methods

The raw materials selected for the study are presented in Tables 1-3.

Preparation of Activated Carbons

The starting raw materials were cut up in small pieces and next subjected to pyrolysis. This process was carried out in a tubular reactor in nitrogen atmosphere. The samples were heated (10 °C/ min) from room temperature to the final pyrolysis temperature of 500. In the final pyrolysis temperature, samples were kept for 60 minutes and then cooled down. The solid products of pyrolysis were next subjected to physical activation [18]. In the case of chemical activation the raw materials were the original precursors which were overnight impregnated into H3PO4 and later submitted to pyrolysis into a stainless steel reactor of 30cm of length per 3cm of diameter. Once the reactor reached the desired temperature the samples were kept at the final temperature according to the experimental conditions of the specific experiment. The activated products then cooled down and washed with enough water till get a neutral pH. Finally, the products were dry at 120°C and then stored [19]. Two different processes were used for the synthesis of the activated carbons from the chars previously obtained by pyrolysis. [18,19]. The experimental conditions used were:

Factorial experimental designs 32 were executed to evaluate the simultaneous influence of the activation conditions on the final product features [14,20]. Following the details for both synthesis processes:

Key properties of the activated carbons prepared were analyzed:

a. Raw material availability;

b. High specific surface area;

c. High mechanical resistance;

d. High adsorption speed.

Characterization of the Raw Materials and Synthetized Activated Carbons

Elemental Analysis: The amount of elements (carbon, hydrogen, nitrogen and oxygen) in the raw materials was determined by an Elemental Analyzer by flash combustion. The samples were firstly dried in an oven at 110°C before the measurement was carried out. The materials was burned at a temperature of 1000°C in flowing oxygen for C, H and N analysis in the analyzer. The CO2, H2O and NOx combustion gases were passed through a reduction tube with helium as the carrier gas to convert the NOx nitrogen oxides into N2 and bind the free oxygen. The CO2 and H2O were measured by selective IR detector. After corresponding absorption of these gases, the content of the remaining nitrogen was determined by thermal conductivity detection. The oxygen was calculated by the difference of carbon, hydrogen and nitrogen.

Apparent Density Measurement: Apparent Density is a measure of the mass per unit volume of a material. It is also called Bulk Density and provides a measure of the “fluffiness” of a material in its natural form. In this work the Standard ASTM D1895 was used. According to this standard the materials are poured into a cylinder of known volume (e.g. 100 mL pipettes) and later weight. Apparent density was calculated as the mass of material divided by the volume occupied into the cylinder [21].

Specific Surface Area Measurement: In order to examine the structure of the synthetized materials, the measurement of the specific surface area of the activated carbons was carried out by gas adsorption isotherms using a Sorptometer applying BET Model. All samples were degassed at 200°C prior to N2 adsorption measurements. Specific surface area was determined by a multipoint BET method using the adsorption data in the relative pressure range: 0.05-0.3 [22,23].

Mechanical Resistance Measurement: The mechanical resistance of the obtained activated carbons was measured through a simple method. A know mass of the granular material was impacted by six glass balls into a semispherical container of stainless steel. The percentage relation between the fragmented mass retained in a 0.5mm mesh and the initial mass is used to estimate the mechanical resistance [24].

Adsorption Speed Evaluation: The adsorption speed was determined by Arrhenius Equation:

where: dX/dt is speed of the adsorption process studied; α is the residual concentration of the adsorbed; and k'ads the apparent kinetic constant of the adsorption process that can be determined by:

Applying logarithm to (Equation 2) brings the possibility to change an exponential equation into a linear dependence, see below:

Plotting ln k'ads vs 1 the activation energy (EA) and the preexponential factor (k0) of the adsorption process studied can be calculated. In the Results discussion ads k'ads will be refers as K for practical reasons.

Designing Process of Activated Carbon Filters

Figure 1 illustrates the process of activated carbon units customized assembling. These filters are very useful to study pollutant gases elimination in automotive engines with the adsorbents produced [25]. The samples, in the form of granules of 2-5 mm in diameter, were packed into a steel column (length 300 mm and internal diameter 90 mm). The gas was passed through the bed of the adsorbent at 0.50 L/min. The concentration of CO, SO2, NO2 and H2S were monitored using a Gas Chromatograph Equipment with standard TCD detector. The concentrations were calculated by integration of the area above the curves.

Pollutants Monitoring at Laboratory Scale

There is no known method available in the open literature which is capable of simultaneously determining all components of combustion gas evaluated here [2]. So the method developed in this work in an innovative alternative for Developing Countries. In order to determine the suitability of the obtained adsorbents in the elimination of CO, SO2, NO2 and H2S, the pollutants removal rate was determined. Figure 2 show a schematic diagram of the customized laboratory system for pollutants monitoring. The system includes, among others:

a. 6 cylinder automotive engine;

b. Activated carbon filter;

c. Exhaust gas analyzer device (Gas Chromatograph);

d. Computer system for data acquisition and recording, etc.

Gas Monitoring System: A standard gas chromatography was used with the following specs:

i. Detector: TCD;

ii. Carrier: Helium;

iii. Column: Porapak Q and Molecular Sieve 5A;

iv. Oven Temperature: 100°C;

v. Sample volume: 1 ml;

vi. Carrier Flow: 25 ml/min;

vii. Detector Temperature: 120°C

Under the described chromatographic conditions, the four gases could be easily separated and quantified [25,26].

The methodology used starting with the preparation of the calibration gas sample by injecting known volumes of each of the four pure gases (CO, SO2, NO2 and H2S) and balance nitrogen into adequate Gas Sampling Bag through the bag’s rubber septum. One mL of the calibration gas mixture and the combustion gases were analyzed by a GC system. Randomly measures of combustion gases before and after the purification process were made on a similar manner in order to evaluate the removal rate of the undesirable pollutants.

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Results and Discussion

Composition and Physical Properties of Raw Materials and Synthetized Products

Table 4 brings a summary of the chemical composition (elemental analysis), such as some physical properties of the 5 precursors studied. Elemental nitrogen, carbon and hydrogen were determined from the elemental analyzer by flash combustion while oxygen was determined by the difference of these three elements. Table 4 shows that the largest amount of element in the raw materials was carbon (except for Corncob which had smaller amount of carbon than oxygen), followed by oxygen, and the smallest amount was nitrogen. The lower content of carbon for Corncob can be attributed to a higher content of volatiles in the structure, translated into a high porosity for the raw material. All precursors do not contain sulfur in their structure, which is very favorable from the ecological and technological points of view.

dap: apparent density; dr: real density; P: porosity

The activation process increases carbon amount (~20- 40%) after modification. On the contrary, there was a reduction in the oxygen content (~20-30%) after physical and chemical modifications. There will be also a reduction of hydrogen amount. The amount of nitrogen was so small for all materials. In Table 4 it can be observed that the initial porosity of all material, except corncobs, have lower values, below 0.5, it makes these materials adequate for activated carbons preparation through chemical or physical activation. The best products synthetized by each process will be reported in Tables 5 & 6.

S: specific surface; K: apparent kinetic constant of the adsorption process; Y: yield; Mr: mechanical resistance; dap: apparent density.

Activated carbon from Central American Mahogany was the more reactive material with a significant porosity development (S = 847 m2/g). Should be noted also that Activated carbon from Mamey Zapote was the best adsorbent (S=940m2/g) and also have the higher mechanical resistance, yield and apparent density, very important for filters durability, but it’s the less available material. Finally it’s necessary to remark that Common Corncobs, a widely available agricultural by-product in Central American Countries, showed the worst results for all adsorbents properties; it can be attributable to the higher porosity of the initial raw material (P = 0.79%).

Table 6 show that activated carbon from Central American Mahogany was again the more reactive material but registered now the higher yield and adsorbent area (S = 832 m2/g). Furthermore, Activated carbon from Mamey Zapote was the second better adsorbent (S = 805 m2/g) and again have the higher mechanical resistance and apparent density. One more time activated carbon from Common Corncobs was the worst adsorbent (S = 470 m2/g). This fact is a consequence of poorly porous structure development during the activation process. Further analysis of the data from Tables 5 & 6 indicates that irrespectively of the variant used, the process of activation leads to further changes in the structure of carbonaceous material. The activated carbons synthetized from different materials studied here differ significantly mainly in the specific surface area development. The adsorbents differ not only in the surface properties but also in their texture and morphology that depend first of all on the variant of activation and the pyrolysis conditions of the initial material. Figure 3 illustrates the differences in specific surface development with both methods and the same materials.

In Figure 3, it can clearly be observed that larger specific surface area developments were achieved with physical activation processes. Those products were the better adsorbents to remove the undesirable pollutants. It also confirms that the factorial experimental designs used are the most suitable to optimize the conditions for activated carbon preparation. Textural parameters significantly affect the adsorption properties of the samples studied. [5] This observation suggests that the functional groups of the surface also have considerable influence on the abilities for combustion gases removal. All adsorbents studied had a rapid decrease in CO, SO2, NO2 and H2S concentration after gases interacted with the corresponding filters. High intensity of these harmful gas reductions at ambient conditions can be the reason for much better adsorption on higher surface area products. This explains the lower efficiency of gases removal by chemically activated carbons. The chemical activation process has the additional disadvantage of the required product washing after preparation which inevitably aggregates additional costs.

Gas Monitoring System

The calibrating gas analysis through the regression equations obtained from triplicate analysis of the gas mixtures at identical concentrations, revealed excellent agreement with the known concentrations. The pollutants monitoring system and analytical method used were effective for the simultaneous analyses of the four toxic combustion gases. Figure 4 shows two examples of 2 chromatograms obtained during the analysis of combustion gases purified with activated carbons from Mamey Zapote physically activated. In this figure it can clearly be observed the significant difference before and after gases interaction with adsorbents that can remove large amount of these undesirable gases with the associated environmental benefits.

The analyses of combustion gases revealed moderate concentrations of H2S and CO but very high concentrations of SO2 and NO2. The most effective adsorbent to remove these gases were the physically activated ones. At the present state of knowledge we can only speculate about the reasons for such poor results obtained from the chemically activated samples. Most probably the reason is the presence of a large number of acidic groups on their surface, in contrast to the physically activated samples, that probably have more basic functional groups present on the surface of the samples. Other chemicals present in the combustion atmospheres did not appear to interfere with the analyses. The chromatographic peaks were well separated and defined and the gases were present in amounts that could be easily determined. An excellent precision with relative standard deviations significantly below 2% were achieved in all gas monitoring analysis. The speed, sensitivity and selectivity of the used method make it suitable for analyzing combustion gas mixture of the four gases studied. Table 7 shows the overall average values of pollutants removal with activated carbons (A.C.) during automotive engines combustion.

In Table 7 it can clearly be observed that SO2 and NO2 amounts monitored are remarkable higher than the average limit values for 24 h. The good news is that the activated carbons studied can efficiently remove about 80% of pollutants in exhaust gases from automotive engines with the added value that the harmful gases concentration goes below the limit values. Figure 5 show the correlation between pollutants removal rate and specific surface area of activated carbons during automotive engines operation. In Figure 5 it can be clearly be observed that higher activated carbons specific surface area translated into higher pollutants removal rates that could be estimated by the equation 4 with a correlation coefficient R2 = 0.995:

A proper choice of the parameters of chemical and physical activation such as temperature, activation time, activates agent, etc., permits getting universal adsorbents showing very good adsorption properties towards such pollutants as SO2, CO, NO2 and H2S, however more studies are needed.

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Conclusion

Agricultural wastes studied here are a feasible alternative for the synthesis of activated carbons for pollutants removal during automotive engines operation. The main features that make these products feasible for the diminishing of automotive engines emission are their high adsorption capacity, approaching its efficiency to the commercial Catalytic Converters such as the cheaper costs and its renewability. Based on these results the granular activated carbons studied, produced in large amounts, are fully exploitable for combustion gases treatment. The complex composition of the flue gas with SO2, CO, NO2 and H2S can be successfully analyzed with good compound separation and repeatability. The method used in this investigation would be also be suitable for combustion toxicology researches and could possibly be easily modified to analyze these gases when they are liberated from biological sources [27].

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Acknowledgement

The author wishes to acknowledge Maria Andrea Camerucci and Ana Lia Cavalieri from Mar del Plata University, Argentina, they provided a crucial help in the experiments of this work.

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juniperpublishers-gjorm · 2 years ago

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Let’s Talk and Grow Together: A Bidirectional Communication between Granulosa- and Oocyte Derived Factors in the Ovary

Abstract

Reproduction, one of the most active and appealing area of research for endocrinologists and reproductive biologists since many a years, has several faces that remains to be unmasked in terms of its regulatory aspects. Available information on the regulation of oocyte development and maturational competence are gaping and needs elucidation to achieve utmost quality of eggs, a major area of concern. The notion of the somatic follicular cells providing an appropriate microenvironment for the development of oocyte throughout its journey has been replaced with the current perception of a complex yet regulated cross-talk between the granulosa-and oocyte-derived factors to orchestrate follicle development. Interestingly, actions of FSH and LH are mediated or modulated by these locally produced non-steroidal peptide factors from the follicular layer and the oocyte itself (insulin-like growth factors (IGFs), epidermal growth factor (EGF) family members, TGFβ super family members etc.), forming an intimate regulatory network within the ovarian follicles. Present article will provide a deeper insight into the need and underlying mechanisms of action of these growth factors in the intraovarian network to sustain a healthy oocyte.

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juniperpublishersna · 3 years ago

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A Case of Vitamin D Toxicity-Juniper Publishers

JUNIPER PUBLISHERS-OPEN ACCESS JOURNAL OF DRUG DESIGNING & DEVELOPMENT

Short Communication

An eighty four year old Caucasian male started taking glucosamine for joint health two years previously. He failed to notice that the glucosamine tablets also contained large doses of cholecalciferol, a precursor of vitamin D. According to the label on the container, two tablets each having five times the recommended daily amount (RDA) were to be taken every day. This was in addition to the vitamin D taken in milk at breakfast, and that in half gram calcium tablets taken twice daily and also vitamin D in a multiple vitamin preparation. All together this added up to 6000 international units (IU) of the vitamin taken each day. The RDA for older people is 800 IU. So he was taking 7.5 times the RDA of vitamin D for over a year. When he discovered the overdose, he stopped taking vitamin D except for milk at breakfast.

Symptoms noted during vitamin D intoxication were mostly central nervous system effects (nervousness, insomnia, irritability, clumsiness) not uncommon in an eighty four year old man. These symptoms persisted for several months even after cessation of vitamin D overdose but gradually decreased in intensity. Submandibular pain also occurred but went away after correcting the overdose. Arthritis also occurred in the knee joints but this did not abate after cessation of the overdose. Reversible Parkinsonism is also seen in vitamin D intoxication. Some increase in tremor was evident in the patient during the overdose but the tremor gradually became less intense with increased time without the vitamin supplement.

The most serious symptoms occurred about two weeks after cessation of the overdose. A severe bradycardia (38 beats/ min) was noted on several occasions at that time. A physician was consulted and did an EKG, a 24 hour Holter monitor and an echocardiogram to document the symptoms. A marked weakness of the heart beat was noted and dizziness was experienced. It took about ten days for the strength of the pulse to return and for the severe bradycardia to correct itself. Some cardiac arrhythmias were present even before the vitamin D overdose (heart block and premature ventricular contractions). These were referred to as benign by a physician and did not change with vitamin D overdose except as mentioned above.

Vitamins are substances that cannot be produced in the body and must be taken in the diet. Since vitamin D can be formed in the body, it is not a true vitamin but is designated a "pro-hormone". However, amounts produced in the body are generally not sufficient, and some vitamin D must also be taken in the diet. Pro-vitamin D compounds are lipid soluble sterols and can accumulate in body fat [1]. They are also slowly removed from the body. This is why symptom scan persist long after the patient stops taking the vitamin D supplement. The pro-vitamin molecule formed by UV light in the skin or taken orally, goes to the liver and is hydroxylated to form cholecalciferol. This substance is not very active physiologically and is hydroxylated in the kidney to form calcetriol which is powerful steroid and works to maintain a constant blood level of calcium by promoting calcium absorption in the gut and by inhibiting calcium re absorption from bone. Blood calcium mediates nerve and muscle activity and must be maintained at a constant level for proper function. To estimate levels of vitamin D in the body, serum concentrations of 25(OH)D are measured. Apparently this is a simple assay and reflects the amounts calcetriol and chole calciferol and other analogs. Some have suggested that it might be better to measure both 25(OH)D and calcitriol but estimating calcitriol is a delicate procedure and is done only in specialized labs [2]. The chemical form of vitamin D which causes symptoms in patients receiving an overdose, have not been fully identified. Calcetriol is the most potent form but when formation of this substance is blocked in knockout mice, it makes no difference in the toxicity of cholecalciferol [3]. It is possible that several vitamin D analogs are responsible for the toxic effects.

Cholecalciferol is not only a dietary supplement but is also a rat poison and can be a problem when ingested by house pets. It is therefore of great interest to veterinarians [4]. Another symptom, more annoying than serious, appeared after terminating excess vitamin D. Cutaneous inflammation on the arms, legs and body with lesions about one to two cm in diameter began to appear about 10 weeks after stopping the excess vitamin intake. Redness and itching were intense but gradually disappeared about five months after correcting the overdose.

There has been a marked increase in marketing of vitamin D supplements recently. One report covering years 2010 to 2014 shows a twenty fold increase in use of these supplements [4,5]. Vitamin D has a reputation of being "healthy and safe" so that physicians promote vitamin D use. So the main message in this publication is that caution is needed in use of vitamin D supplements which can cause serious and even lethal effects if used over a long time interval.

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