Cytoplasmic and plasma membrane ultrastructure of Paracoccidioides brasiliensis yeast-phase cells as revealed by freeze-etching

1990 ◽  
Vol 94 (8) ◽  
pp. 1118-1122 ◽  
Author(s):  
K. Takeo ◽  
A. Sano ◽  
K. Nishimura ◽  
M. Miyaji ◽  
M. Franco ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Paracoccidioides Brasiliensis ◽  
Freeze Etching ◽  
Yeast Phase ◽  
Membrane Ultrastructure

The Fine-Structural Organization of the Brush Border of Intestinal Epithelial Cells

1971 ◽  
Vol 8 (3) ◽  
pp. 573-599
Author(s):  
T. M. MUKHERJEE ◽  
L. A. STAEHELIN
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Brush Border ◽  
Intestinal Epithelial Cells ◽  
Membrane Surface ◽  
Intestinal Epithelial ◽  
The Core ◽  
Unit Structure ◽  
Terminal Web ◽  
Freeze Etching

The fine structure of the brush border of intestinal epithelial cells of the mouse has been studied with both normal sectioning and freeze-etching techniques. Freeze-etching reveals the plasma membrane of the microvilli as consisting of a continuous layer, that is split during the cleaving process, in which numerous particles, 5-9 nm in diameter, are embedded, while other particle-like structures, with diameters of 7-10 nm, appear attached to the true outer membrane surface. The mucopolysaccharide surface coats of the microvilli show up more clearly in sectioned material than in freeze-etched specimens. Inside each microvillus 2 different filament systems can be demonstrated: (1) bundles of fairly closely packed and straight core microfilaments, which lead into the tip of the microvillus, and (2) short cross-filaments. Under suitable conditions the core microfilaments display a sub-unit structure with a repeating distance of approximately 6 nm. The diameter of a microfilament can vary along its length from 6 to 11 nm. Two strands of globular particles wound helically around each other seem to make up each microfilament. These and other data support the idea that the core microfilaments are actin-like. No substructure has been found on the cross-filaments, which have an orientation approximately radial to the axis of the microvilli and seem to be attached at one end to the core microfilaments and at the other to the inner surface of the microvillous membrane. The interwoven terminal web filaments also show no substructure. They form a continuous flexible platform-like structure into which the bundles of core microfilaments extend. Some terminal web filaments appear attached to the plasma membrane between the microvilli. It is suggested that the core microfilaments represent mechanical supporting elements and that the terminal web and cross-filaments are tensile elements of the brush border. In addition all 3 filament systems may also be involved in possible contractile movements of the microvilli.

scholarly journals Parallel Acquisition of Plasma Membrane Ultrastructure and Cytosolic Protein Localisation in Cultured Cells via Correlated Immunogold SEM

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1329
Author(s):  
Isabell Begemann ◽  
Ulrike Keller ◽  
Harald Nüsse ◽  
Jürgen Klingauf ◽  
Milos Galic
Keyword(s):  
Plasma Membrane ◽  
Cultured Cells ◽  
Intact Cell ◽  
Protein Localization ◽  
Integrated Approach ◽  
Detection Methods ◽  
Parallel Acquisition ◽  
Cytosolic Protein ◽  
Correlated Information ◽  
Membrane Ultrastructure

Scanning electron microscopy (SEM) takes advantage of distinct detectors to visualise secondary and back-scattering electrons. Here, we report an integrated approach that relies on these two detection methods to simultaneously acquire correlated information on plasma membrane topography and curvature-sensitive cytosolic protein localization in intact cell samples. We further provide detailed preparation and staining protocols, as well as a thorough example-based discussion for imaging optimisation. Collectively, the presented method enables rapid and precise analysis of cytosolic proteins adjacent to cellular membranes with a resolution of ~100 nm, without time-consuming preparations or errors induced by sequential visualisation present in fluorescence-based correlative approaches.

scholarly journals Eudiplozoon nipponicum: morphofunctional adaptations of diplozoid monogeneans for confronting their host

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Andrea Valigurová ◽  
Naděžda Vaškovicová ◽  
Milan Gelnar ◽  
Magdaléna Kováčiková ◽  
Iveta Hodová
Keyword(s):  
Plasma Membrane ◽  
Microscopic Analysis ◽  
Muscle Layer ◽  
Biological Properties ◽  
Fish Host ◽  
Model Organisms ◽  
Apical Plasma Membrane ◽  
Biological Interactions ◽  
Freeze Etching ◽  
Eudiplozoon Nipponicum

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.

scholarly journals Eudiplozoon Nipponicum: Morphofunctional Adaptations of Diplozoid Monogeneans for Confronting Their Host

2020 ◽  
Author(s):  
Andrea Valigurová ◽  
Naděžda Vaškovicová ◽  
Milan Gelnar ◽  
Magdaléna Kováčiková ◽  
Iveta Hodová
Keyword(s):  
Plasma Membrane ◽  
Microscopic Analysis ◽  
Muscle Layer ◽  
Biological Properties ◽  
Fish Host ◽  
Model Organisms ◽  
Apical Plasma Membrane ◽  
Biological Interactions ◽  
Freeze Etching ◽  
Eudiplozoon Nipponicum

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.

scholarly journals Cyclophosphamide effect on paracoccidioidomycosis in the rat

1995 ◽  
Vol 37 (3) ◽  
pp. 219-224 ◽  
Author(s):  
J. L. Blejer ◽  
C. M. Godio ◽  
R Negroni ◽  
M. R. Nejamkis
Keyword(s):  
T Lymphocyte ◽  
Paracoccidioides Brasiliensis ◽  
Lymphocyte Subset ◽  
Control Group ◽  
Spleen Cells ◽  
Phase Form ◽  
Infected Donor ◽  
Splenic Cell ◽  
Yeast Phase ◽  
Suppressor T Lymphocyte

Paracoccidioidomycosis is an endemic fungal disease widely distributed throughout Latin America. The potent immunosuppressor cyclophosphamide (CY) has been used to modulate host immune response to Paracoccidioides brasiliensis in an experimental model. Inbred male Buffalo/Sim rats weighing 250-300 g were inoculated with 5 x 10(6) P. brasiliensis cells of the yeast phase form by intracardiac route. One group of animals was treated with 20 mg/kg body weight at days +4, +5, +6, +7, +11 and +12 post-infection (pi.), while a control group was infected alone. No mortality was recorded in either group. Treated rats presented: a) a decrease in granuloma size, which contained less fungal cells; b) a lack of specific antibodies up to 35 days pi., and c) a significant increase in the footpad swelling test (DTH) against paracoccidioidin. Splenic cell transfer from CY-treated P. brasiliensis-infected donors to recipients infected alone led to a significant increase in DTH response in the latter versus untreated infected controls. Likewise, in treated infected recipients transferred with untreated infected donor spleen cells, footpad swelling proved greater than in controls. Thus, it would seem that each successive suppressor T lymphocyte subset belonging to the respective cascade may be sensitive to repeated CY doses administered up to 12 days pi.. Alternatively, such CY schedule may induce the appearance of a T cell population capable of amplifying DTH response.

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