#serial block-face scanning electron microscopy

[bpod-bpod]

Powering Down Hearing

Your hearing depends on hair cells in your inner ear. When loud noises or ageing destroys these cells, it's their mitochondria – the powerhouses of your cells – that are involved in their downfall. Moreover, faults in over 30 genes key to mitochondrial activity are known to cause deafness. Yet little is known about hair cell mitochondria biology. Researchers now investigate in zebrafish. Using serial block-face scanning electron microscopy, they found mitochondria are more densely packed in hair cells (pictured, white) compared with support cells. These mitochondria also had a distinct architecture – multiple small mitochondria in the upper halves of cells and fine networks in the lower halves. In zebrafish with a faulty opa1 gene – a gene known to be mutated in human deafness – mitochondria function was disrupted. In mutants where hair cell mechanics were disrupted, so too was mitochondria architecture. This furthers our understanding of mitochondria-related deafness.

Written by Lux Fatimathas

Image from work by Andrea McQuate, Sharmon Knecht and David W Raible

Department of Biological Structure, University of Washington, Seattle, WA, USA

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in eLife, March 2023

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[cellimagelibrary]

Image of the Week - February 5, 2018

CIL:50201 - http://www.cellimagelibrary.org/images/50201

Description: A longstanding limitation of imaging with serial block-face scanning electron microscopy is specimen surface charging. This charging is largely due to the difficulties in making biological specimens and the resins in which they are embedded sufficiently conductive. Local accumulation of charge on the specimen surface can result in poor image quality and distortions. Even minor charging can lead to misalignments between sequential images of the block-face due to image jitter. Typically, variable-pressure SEM is used to reduce specimen charging, but this results in a significant reduction to spatial resolution, signal-to-noise ratio and overall image quality. Here we show the development and application of a simple system that effectively mitigates specimen charging by using focal gas injection of nitrogen over the sample block-face during imaging. A standard gas injection valve is paired with a precisely positioned but retractable application nozzle, which is mechanically coupled to the reciprocating action of the serial block-face ultramicrotome. This system enables the application of nitrogen gas precisely over the block-face during imaging while allowing the specimen chamber to be maintained under high vacuum to maximise achievable SEM image resolution. The action of the ultramicrotome drives the nozzle retraction, automatically moving it away from the specimen area during the cutting cycle of the knife. The device described was added to a Gatan 3View system with minimal modifications, allowing high-resolution block-face imaging of even the most charge prone of epoxy-embedded biological samples.

Authors: Tom Deerinck, Tristan Shone, Eric Bushong, Ranjan Ramachandra,  Steven Peltier, and Mark Ellisman

Licensing: Public Domain: This image is in the public domain and thus free of any copyright restrictions. However, as is the norm in scientific publishing and as a matter of courtesy, any user should credit the content provider for any public or private use of this image whenever possible.

[pinoywhealth]

Researchers used a newly developed imaging technique called serial block face scanning electron microscopy, to produce a digital reconstruction of eye tissues from the outer retina, at very high resolution. This is the first time this technology has been used to fully...

[kreuzaderny]

Three-dimensional visualization and a deep-learning model reveal complex fungal parasite networks in behaviorally manipulated ants

Some microbes possess the ability to adaptively manipulate host behavior. To better understand how such microbial parasites control animal behavior, we examine the cell-level interactions between the species-specific fungal parasite Ophiocordyceps unilateralis sensu lato and its carpenter ant host (Camponotus castaneus) at a crucial moment in the parasite’s lifecycle: when the manipulated host fixes itself permanently to a substrate by its mandibles. The fungus is known to secrete tissue-specific metabolites and cause changes in host gene expression as well as atrophy in the mandible muscles of its ant host, but it is unknown how the fungus coordinates these effects to manipulate its host’s behavior. In this study, we combine techniques in serial block-face scanning-electron microscopy and deep-learning–based image segmentation algorithms to visualize the distribution, abundance, and interactions of this fungus inside the body of its manipulated host. Fungal cells were found throughout the host body but not in the brain, implying that behavioral control of the animal body by this microbe occurs peripherally. Additionally, fungal cells invaded host muscle fibers and joined together to form networks that encircled the muscles. These networks may represent a collective foraging behavior of this parasite, which may in turn facilitate host manipulation.

sooo... not so much zombified ants as sunken-placed ants

[bitesizebioworld]

Data Analysis for Three-dimensional Volume Scanning Electron Microscopy

 In recent years, three-dimensional (3D) scanning electron microscopy techniques have gained recognition in the biological sciences. In particular, array tomography, serial block face scanning electron microscopy (SBFSEM) and focused ion beam scanning electron microscopy (FIBSEM) (described in Three-Dimensional Scanning Electron Microscopy for Biology) have shown an increase in biological applications, elucidating ultrastructural details of cells […]

The post Data Analysis for Three-dimensional Volume Scanning Electron Microscopy appeared first on Bitesize Bio.

[bpod-bpod]

Power Insight

The backs of our eyes are studded with millions of photoreceptors, cells in the retina triggered by light to help send electrical impulses to the brain. Differently-shaped ‘rod’ and ‘cone’ photoreceptors work to keep our vision precise and sensitive – and require a constant supply of energy. Here we see bundles cellular power stations – or mitochondria – highlighted in different colours around a single cone cell from a macaque monkey’s eye. To capture this level of detail, the retina was set in resin and a series of pictures taken while shaving away thin layers of tissue. The technique, called serial block face scanning electron microscopy, reveals the mitochondria have pointy 'tops' (left) and swollen bases (right), 10,000 times smaller than a bunch of asparagus. Researchers believe this arrangement helps with mitochondrial fusion – when the powerhouses join and rejuvenate, important to the health of retinal cells in monkeys and humans alike.

Written by John Ankers

Image from work by Matthew J. Hayes and colleagues

University College London Institute of Ophthalmology, London UK

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Scientific Reports, September 2021

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