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BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Andrea Valigurová ◽  
Naděžda Vaškovicová ◽  
Milan Gelnar ◽  
Magdaléna Kováčiková ◽  
Iveta Hodová

Abstract Background Monogeneans, in general, show a range of unique adaptations to a parasitic lifestyle, making this group enormously diverse. Due to their unique biological properties, diplozoid monogeneans represent an attractive model group for various investigations on diverse biological interactions. However, despite numerous studies, there are still gaps in our knowledge of diplozoid biology and morphofunctional adaptations. Results In this study, we provide a comprehensive microscopic analysis of systems/structures involved in niche searching, sensing and self-protection against the host environment, and excretory/secretory processes in Eudiplozoon nipponicum. Freeze-etching enabled us to detect syncytium organisational features not visible by TEM alone, such as the presence of a membrane subjacent to the apical plasma membrane (separated by a dense protein layer) and a lack of basal plasma membrane. We located several types of secretory/excretory vesicles and bodies, including those attached to the superficial membranes of the tegument. Giant unicellular glands were seen accumulating predominantly in the apical forebody and hindbody haptor region. Muscle layer organisation differed from that generally described, with the outer circular and inner longitudinal muscles being basket-like interwoven by diagonal muscles with additional perpendicular muscles anchored to the tegument. Abundant muscles within the tegumentary ridges were detected, which presumably assist in fixing the parasite between the gill lamellae. Freeze-etching, alongside transmission electron and confocal microscopy with tubulin labelling, enabled visualisation of the protonephridia and nervous system, including the peripheral network and receptor innervation. Three types of receptor were identified: 1) uniciliated sensory endings with a subtle (or missing) tegumentary rim, 2) obviously raised uniciliated receptors with a prominent tegumentary rim (packed with massive innervation and muscles) and 3) non-ciliated papillae (restricted to the hindbody lateral region). Conclusions This study points to specific morphofunctional adaptations that have evolved in diplozoid monogeneans to confront their fish host. We clearly demonstrate that the combination of different microscopic techniques is beneficial and can reveal hidden differences, even in much-studied model organisms such as E. nipponicum.


2020 ◽  
Author(s):  
Andrea Valigurová ◽  
Naděžda Vaškovicová ◽  
Milan Gelnar ◽  
Magdaléna Kováčiková ◽  
Iveta Hodová

Abstract Background: Monogeneans, in general, show a range of unique adaptations to a parasitic lifestyle, making this group enormously diverse. Due to their unique biological properties, diplozoid monogeneans represent an attractive model group for various investigations on diverse biological interactions. However, despite numerous studies, there are still gaps in our knowledge of diplozoid biology and morphofunctional adaptation.Results: In this study, we provide a complex microscopic analysis of systems/structures involved in niche searching, sensing and self-protection against the host environment, and excretory/secretory processes in Eudiplozoon nipponicum. Freeze-etching enabled us to detect syncytium organisational features not visible by TEM alone, such as the presence of a membrane subjacent to the apical plasma membrane (separated by a dense protein layer) and a lack of basal plasma membrane. We located several types of secretory/excretory vesicles and bodies, including those attached to the superficial membranes of the tegument. Giant unicellular glands were seen accumulating predominantly in the apical forebody and hindbody haptor region. Muscle layer organisation differed from that generally described, with the outer circular and inner longitudinal muscles being basket-like interwoven by diagonal muscles with additional perpendicular muscles anchored to the tegument. Abundant muscles within the tegumentary ridges were detected, which presumably assist in fixing the parasite between the gill lamellae. Freeze-etching, alongside transmission electron and confocal microscopy with tubulin labelling, enabled visualisation of the protonephridia and nervous system, including the peripheral network and receptor innervation. Three types of receptor were identified: 1) uniciliated sensory endings with a less prominent (or missing) tegumentary rim, 2) obviously raised uniciliated receptors with a prominent tegumentary rim (packed with massive innervation and muscles) and 3) non-ciliated papillae (restricted to the hindbody lateral region). Conclusions: This study points to specific morphofunctional adaptations that have evolved in diplozoid monogeneans to confront their fish host. We clearly demonstrate that the combination of different microscopic techniques is beneficial and can reveal hidden differences, even in much-studied model organisms such as E. nipponicum.


2020 ◽  
Author(s):  
Andrea Valigurová ◽  
Naděžda Vaškovicová ◽  
Milan Gelnar ◽  
Magdaléna Kováčiková ◽  
Iveta Hodová

Abstract BackgroundMonogeneans, in general, show a range of unique adaptations to a parasitic lifestyle, making this group enormously diverse. Due to their unique biological properties, diplozoid monogeneans represent an attractive model group for various investigations on diverse biological interactions. However, despite numerous studies, there are still gaps in our knowledge of diplozoid biology and morphofunctional adaptation.ResultsIn this study, we provide a complex microscopic analysis of systems/structures involved in niche searching, sensing and self-protection against the host environment, and excretory/secretory processes in Eudiplozoon nipponicum. Freeze-etching enabled us to detect syncytium organisational features not visible by TEM alone, such as the presence of a membrane subjacent to the apical plasma membrane (separated by a dense protein layer) and a lack of basal plasma membrane. We located several types of secretory/excretory vesicles and bodies, including those attached to the superficial membranes of the tegument. Giant unicellular glands were seen accumulating predominantly in the apical forebody and hindbody haptor region. Muscle layer organisation differed from that generally described, with the outer circular and inner longitudinal muscles being basket-like interwoven by diagonal muscles with additional perpendicular muscles anchored to the tegument. Abundant muscles within the tegumentary ridges were detected, which presumably assist in fixing the parasite between the gill lamellae. Freeze-etching, alongside transmission electron and confocal microscopy with tubulin labelling, enabled visualisation of the protonephridia and nervous system, including the peripheral network and receptor innervation. Three types of receptor were identified: 1) uniciliated sensory endings with a less prominent (or missing) tegumentary rim, 2) obviously raised uniciliated receptors with a prominent tegumentary rim (packed with massive innervation and muscles) and 3) non-ciliated papillae (restricted to the hindbody lateral region). ConclusionsThis study points to specific morphofunctional adaptations that have evolved in diplozoid monogeneans to confront their fish host. We clearly demonstrate that the combination of different microscopic techniques is beneficial and can reveal hidden differences, even in much-studied model organisms such as E. nipponicum.


2020 ◽  
Vol 9 (6) ◽  
pp. 1616 ◽  
Author(s):  
Lukas Prantl ◽  
Andreas Eigenberger ◽  
Sebastian Gehmert ◽  
Silke Haerteis ◽  
Thiha Aung ◽  
...  

Vitamin C is an essential nutrient for humans and is involved in a plethora of health-related functions. Several studies have shown a connection between vitamin C intake and an improved resistance to infections that involves the immune system. However, the body cannot store vitamin C and both the elevated oral intake, and the intravenous application have certain disadvantages. In this study, we wanted to show a new formulation for the liposomal packaging of vitamin C. Using freeze etching electron microscopy, we show the formed liposomes. With a novel approach of post-processing procedures of real-time sonography that combines enhancement effects by contrast-like ultrasound with a transducer, we wanted to demonstrate the elevated intestinal vitamin C resorption on four participants. With the method presented in this study, it is possible to make use of the liposomal packaging of vitamin C with simple household materials and equipment for intake elevation. For the first time, we show the enhanced resorption of ingested liposomes using microbubble enhanced ultrasound imaging.


Microscopy ◽  
2020 ◽  
Vol 69 (6) ◽  
pp. 350-359
Author(s):  
Nobuhiro Morone ◽  
Eiji Usukura ◽  
Akihiro Narita ◽  
Jiro Usukura

Abstract Unroofing, which is the mechanical shearing of a cell to expose the cytoplasmic surface of the cell membrane, is a unique preparation method that allows membrane cytoskeletons to be observed by cryo-electron microscopy, atomic force microscopy, freeze-etching electron microscopy and other methods. Ultrasound and adhesion have been known to mechanically unroof cells. In this study, unroofing using these two means was denoted sonication unroofing and adhesion unroofing, respectively. We clarified the mechanisms by which cell membranes are removed in these unroofing procedures and established efficient protocols for each based on the mechanisms. In sonication unroofing, fine bubbles generated by sonication adhered electrostatically to apical cell surfaces and then removed the apical (dorsal) cell membrane with the assistance of buoyancy and water flow. The cytoplasmic surface of the ventral cell membrane remaining on the grids became observable by this method. In adhesion unroofing, grids charged positively by coating with Alcian blue were pressed onto the cells, thereby tightly adsorbing the dorsal cell membrane. Subsequently, a part of the cell membrane strongly adhered to the grids was peeled from the cells and transferred onto the grids when the grids were lifted. This method thus allowed the visualization of the cytoplasmic surface of the dorsal cell membrane. This paper describes robust, improved protocols for the two unroofing methods in detail. In addition, micro-unroofing (perforation) likely due to nanobubbles is introduced as a new method to make cells transparent to electron beams.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Willy W. Sun ◽  
Evan S. Krystofiak ◽  
Alejandra Leo-Macias ◽  
Runjia Cui ◽  
Antonio Sesso ◽  
...  

AbstractThe glycocalyx is a highly hydrated, glycoprotein-rich coat shrouding many eukaryotic and prokaryotic cells. The intestinal epithelial glycocalyx, comprising glycosylated transmembrane mucins, is part of the primary host-microbe interface and is essential for nutrient absorption. Its disruption has been implicated in numerous gastrointestinal diseases. Yet, due to challenges in preserving and visualizing its native organization, glycocalyx structure-function relationships remain unclear. Here, we characterize the nanoarchitecture of the murine enteric glycocalyx using freeze-etching and electron tomography. Micrometer-long mucin filaments emerge from microvillar-tips and, through zigzagged lateral interactions form a three-dimensional columnar network with a 30 nm mesh. Filament-termini converge into globular structures ~30 nm apart that are liquid-crystalline packed within a single plane. Finally, we assess glycocalyx deformability and porosity using intravital microscopy. We argue that the columnar network architecture and the liquid-crystalline packing of the filament termini allow the glycocalyx to function as a deformable size-exclusion filter of luminal contents.


2019 ◽  
Vol 67 ◽  
pp. 357-370 ◽  
Author(s):  
D. W. T. Crompton

Don Northcote became eminent in the field of plant biochemistry following his identification of the processes involved in the synthesis and deposition of polysaccharides that constitute the cell wall of plants. His researches spanned lower and higher plant species and he showed by the application of a variety of experimental techniques, including radioautography, electrophoresis, freeze etching and the novel use of electron microscopy, that much of the material of the cell wall is synthesized in cytoplasmic organelles before being transported to the developing wall in vesicles assembled from the membranes of the Golgi body. His findings inspired many colleagues to build on the foundation he laid for understanding the biochemistry of cell morphogenesis. Nearly his entire career was spent in fundamental research and teaching in the Department of Biochemistry, University of Cambridge, from 1948 until his retirement in 1992. In addition, he was a fellow of St John's College, Cambridge, from 1960 to 1976, and he served Sidney Sussex College, Cambridge, as master from 1976 to 1992.


2016 ◽  
Vol 27 (3) ◽  
pp. 421-423
Author(s):  
Daniel Branton

In 1961, the development of an improved freeze-etching (FE) procedure to prepare rapidly frozen biological cells or tissues for electron microscopy raised two important questions. How does a frozen cell membrane fracture? What do the extensive face views of the cell’s membranes exposed by the fracture process of FE tell us about the overall structure of biological membranes? I discovered that all frozen membranes tend to split along weakly bonded lipid bilayers. Consequently, the fracture process exposes internal membrane faces rather than either of the membrane’s two external surfaces. During etching, when ice is allowed to sublime after fracturing, limited regions of the actual membrane surfaces are revealed. Examination of the fractured faces and etched surfaces provided strong evidence that biological membranes are organized as lipid bilayers with some proteins on the surface and other proteins extending through the bilayer. Membrane splitting made it possible for electron microscopy to show the relative proportion of a membrane’s area that exists in either of these two organizational modes.


Author(s):  
Douglas E. Chandler ◽  
William P. Sharp

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