scholarly journals A FIBER APPARATUS IN THE NUCLEUS OF THE YEAST CELL

1966 ◽  
Vol 29 (1) ◽  
pp. 129-151 ◽  
Author(s):  
C. F. Robinow ◽  
J. Marak
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Dense Matter ◽  
Short Fiber ◽  
Yeast Cells ◽  
Acid Fuchsin ◽  
Fine Grained ◽  
New Information ◽  
Thin Electron ◽  
Iron Alum

The structure and mode of division of the nucleus of budding yeast cells have been studied by phase-contrast microscopy during life and by ordinary microscopy after Helly fixation. The components of the nucleus were differentially stained by the Feulgen procedure, with Giemsa solution after hydrolysis, and with iron alum haematoxylin. New information was obtained in cells fixed in Helly's by directly staining them with 0.005% acid fuchsin in 1% acetic acid in water. Electron micrographs have been made of sections of cells that were first fixed with 3% glutaraldehyde, then divested of their walls with snail juice, and postfixed with osmium tetroxide. Light and electron microscopy have given concordant information about the organization of the yeast nucleus. A peripheral segment of the nucleus is occupied by relatively dense matter (the "peripheral cluster" of Mundkur) which is Feulgen negative. The greater part of the nucleus is filled with fine-grained Feulgen-positive matter of low density in which chromosomes could not be identified. Chromosomes become visible in this region under the light microscope at meiosis. In the chromatin lies a short fiber with strong affinity for acid fuchsin. The nucleus divides by elongation and constriction, and during this process the fiber becomes long and thin. Electron microscopy has resolved it into a bundle of dark-edged 150 to 180 A filaments which extends between "centriolar plaques" that are attached to the nuclear envelope.

Scale structure and taxonomy of some species of Raphidocystis, Raphidiophrys, and Pompholyxophrys (Heliozoea) including descriptions of six new taxa

1985 ◽  
Vol 63 (8) ◽  
pp. 1944-1961 ◽  
Author(s):  
K. H. Nicholls ◽  
M. Dürrschmidt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
New Zealand ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Scale Structure ◽  
Taxonomic Descriptions ◽  
Transmission Electron ◽  
New Information ◽  
Freshwater Habitats

Sixteen taxa of the genera Raphidocystis, Raphidiophrys, and Pompholyxophrys from freshwater habitats in Canada, Chile, and New Zealand were studied by light and electron microscopy. Six taxa are described as new: Raphidocystis glabra, Raphidiophrys minuta, Raphidiophrys orbicularis ssp. orbicularis, R. orbicularis ssp. ovalis, Pompholyxophrys stellata, and P. ossea. New information on scale structure and arrangement based on scanning and transmission electron microscopy amplifies the taxonomic descriptions of Raphidiophrys ambigua, R. pallida, R. elegans, R. intermedia, R. marginata, R. symmetrica, Pompholyxophrys punicea, P. exigua, and P. ovuligera, which were previously imperfectly known by light microscopy only.

scholarly journals WOUND HEALING AND COLLAGEN FORMATION

1962 ◽  
Vol 12 (3) ◽  
pp. 533-551 ◽  
Author(s):  
Russell Ross ◽  
Earl P. Benditt
Keyword(s):  
Electron Microscopy ◽  
Wound Healing ◽  
Protein Synthesis ◽  
Small Groups ◽  
Guinea Pigs ◽  
Light And Electron Microscopy ◽  
Dense Matter ◽  
Skin Wounds ◽  
Intercellular Spaces ◽  
Collagen Formation

The sequence encountered in healing skin wounds in scorbutic guinea pigs has been examined by methods of light and electron microscopy. Linear incisions in the skin of female guinea pigs fed a scorbutigenic diet were allowed to heal. The wounds were removed for examination at 1, 3, 5, 9, and 14 days after wounding. The fibroblasts of the scorbutic wounds differ from those of the controls in three major aspects. First, little collagen is present within the intercellular spaces, although small groups of individual collagen fibrils can be found adjacent to some of the fibroblasts; in addition, large amounts of somewhat fibrillar, poorly structured, dense matter are present throughout the extracellular regions. The second alteration consists of large aggregates of intracytoplasmic lipid deposits present within the majority of the fibroblasts. Third, the endoplasmic reticulum of the fibroblasts is altered in form from that of the controls. The profiles of the cisternae are round, non-continuous within the plane of section, and are less extensively developed than in the controls. An increased macrophagic activity of the histiocytes is also described. These changes are discussed in light of the available biochemical data associated with this abnormality of protein synthesis.

scholarly journals Correlative light and electron microscopy suggests that mutant huntingtin dysregulates the endolysosomal pathway in presymptomatic Huntington’s disease

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Ya Zhou ◽  
Thomas R. Peskett ◽  
Christian Landles ◽  
John B. Warner ◽  
Kirupa Sathasivam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Light And Electron Microscopy ◽  
Yeast Cells ◽  
Disease Stage ◽  
Dependent Manner ◽  
Residual Bodies

AbstractHuntington’s disease (HD) is a late onset, inherited neurodegenerative disorder for which early pathogenic events remain poorly understood. Here we show that mutant exon 1 HTT proteins are recruited to a subset of cytoplasmic aggregates in the cell bodies of neurons in brain sections from presymptomatic HD, but not wild-type, mice. This occurred in a disease stage and polyglutamine-length dependent manner. We successfully adapted a high-resolution correlative light and electron microscopy methodology, originally developed for mammalian and yeast cells, to allow us to correlate light microscopy and electron microscopy images on the same brain section within an accuracy of 100 nm. Using this approach, we identified these recruitment sites as single membrane bound, vesicle-rich endolysosomal organelles, specifically as (1) multivesicular bodies (MVBs), or amphisomes and (2) autolysosomes or residual bodies. The organelles were often found in close-proximity to phagophore-like structures. Immunogold labeling localized mutant HTT to non-fibrillar, electron lucent structures within the lumen of these organelles. In presymptomatic HD, the recruitment organelles were predominantly MVBs/amphisomes, whereas in late-stage HD, there were more autolysosomes or residual bodies. Electron tomograms indicated the fusion of small vesicles with the vacuole within the lumen, suggesting that MVBs develop into residual bodies. We found that markers of MVB-related exocytosis were depleted in presymptomatic mice and throughout the disease course. This suggests that endolysosomal homeostasis has moved away from exocytosis toward lysosome fusion and degradation, in response to the need to clear the chronically aggregating mutant HTT protein, and that this occurs at an early stage in HD pathogenesis.

scholarly journals In vitro fusion of Acanthamoeba phagolysosomes. I. Demonstration and quantitation of vacuole fusion in Acanthamoeba homogenates.

1976 ◽  
Vol 68 (2) ◽  
pp. 319-338 ◽  
Author(s):  
P J Oates ◽  
O Touster
Keyword(s):  
Electron Microscopy ◽  
Blood Cells ◽  
Fusion Reaction ◽  
Light And Electron Microscopy ◽  
Yeast Cells ◽  
Eosin Y ◽  
Vacuole Fusion ◽  
Lysosomal System

Fusion of phagolysosomes (PLs) has been demonstrated to occur in vitro. Two separate cell homogenates of the ameba Acanthamoeba sp. (Neff) were prepared, each rich in PLs labeled with distinctive particulate markers. Portions of each were incubated together in vitro and fusion occurred as evidenced by the appearance of PLs containing both types of markers. Fusion was confirmed by electron microscopy, including serial sectioning. The membranes of fused vacuoles excluded the dye eosin Y. Surviving cells in the homogenates were not responsible for the observed fusion. Fusion was obtained using either synthetic markers (polystyrene and polyvinyltoluene latex) or biological markers (autoclaved yeast cells and glutaraldehyde-fixed goat red blood cells), or a combination of both. The specificity of PL fusion in vivo appeared to be maintained in vitro. As determined by light and electron microscopy, the fusion reaction was dependent on time and temperature, and on the initial presence of membrane around both marker particles. A minimum of 10% of the vacuoles fused by 10 min of incubation at 30 degrees C, and no rupture of the vacuoles was detected during this time. After 10 min of incubation, vacuole rupture began and fusion ceased. At a constant initial vacuole concentration, the extent of PL fusion in vitro was quantitatively reproducible. This appears to be a promising system for further investigation of membrane fusion in the lysosomal system.

scholarly journals Correlative light and electron microscopy reveals that mutant huntingtin dysregulates the endolysosomal pathway in presymptomatic Huntington’s disease

2021 ◽  
Author(s):  
Ya Zhou ◽  
Thomas R. Peskett ◽  
Christian Landles ◽  
John B. Warner ◽  
Kirupa Sathasivam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Light And Electron Microscopy ◽  
Yeast Cells ◽  
Disease Stage ◽  
Dependent Manner ◽  
Residual Bodies

AbstractHuntington’s disease (HD) is a late onset, inherited neurodegenerative disorder for which early pathogenic events remain poorly understood. Here we show that mutant exon 1 HTT proteins are recruited to a subset of cytoplasmic aggregates in the cell bodies of neurons in brain sections from presymptomatic HD, but not wild-type, mice. This occurred in a disease stage and polyglutamine-length dependent manner. We successfully adapted a high-resolution correlative light and electron microscopy methodology, originally developed for mammalian and yeast cells, to allow us to correlate light microscopy and electron microscopy images on the same brain section within an accuracy of 100 nm. Using this approach, we identified these recruitment sites as single membrane bound, vesicle-rich endolysosomal organelles, specifically as (i) multivesicular bodies (MVBs), or amphisomes and (ii) autolysosomes or residual bodies. The organelles were often found in close proximity to phagophore-like structures. Immunogold labeling localized mutant HTT to non-fibrillar, electron lucent structures within the lumen of these organelles. In presymptomatic HD, the recruitment organelles were predominantly MVBs/amphisomes, whereas in late-stage HD, there were more autolysosomes or residual bodies. Electron tomograms indicated the fusion of small vesicles with the vacuole within the lumen, suggesting that MVBs develop into residual bodies. We found that markers of MVB-related exocytosis were depleted in presymptomatic mice and throughout the disease course. This suggests that endolysosomal homeostasis has moved away from exocytosis toward lysosome fusion and degradation, in response to the need to clear the chronically aggregating mutant HTT protein, and that this occurs at an early stage in HD pathogenesis.

Revision of the type material of Diploneis zannii Frenguelli (Bacillariophyceae)

Phytotaxa ◽  
2018 ◽  
Vol 351 (3) ◽  
pp. 239
Author(s):  
AMELIA A. VOUILLOUD ◽  
SILVIA E. SALA ◽  
SANTIAGO HEGUILOR
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Type Material ◽  
Subtropical Wetland ◽  
New Information ◽  
Emended Diagnosis

Diploneis zannii was first described from the Esteros del Iberá, a subtropical wetland from Argentina. Type material of the species was studied with light and electron microscopy and compared to some similar taxa: D. fusca, D. insolitus, D. lenzii, D. smithii and D. finnica and other material collected from Brazil and Uruguay. We confirm the validity of Diploneis zannii as a species and present an emended diagnosis derived from new information on its morphology. A lectotype and isolectotype are designated.

Correlative light microscopy, electron microscopy, and cytochemistry of cytoskeletal structures in motile fibroblasts

1991 ◽  
Vol 49 ◽  
pp. 168-169
Author(s):  
Julian P. Heath ◽  
Donna Turner ◽  
Bruce F. Holifield
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Differential Interference Contrast Microscopy ◽  
Dynamic Interactions ◽  
Fine Grained ◽  
Motile Cells ◽  
Contrast Microscopy ◽  
Carbon Coated ◽  
Interference Contrast Microscopy ◽  
Triton X

Contrast-enhanced video differential interference contrast microscopy (VDICM) is revealing new details about the dynamics of F-actin assemblies in motile cells. We are using correlative single cell light and electron microscopy and immunocytochemistry to understand the dynamic interactions of the actin cytoskeleton in lamellipodia and the leading lamella.Fibroblasts were cultured on carbon-coated glass #1 coverslips and examined on a Zeiss Axiophot. Cells were perfused with 1% glutaraldehyde (GA) in PIPES buffer and fixed for 15 min., quenched with 1 mg/ml borohydride/PBS and extracted with 0.1% Triton X-100 in PBS for 1 min. Cell postions were marked with a diamond objective, and the cells were incubated for 30 min. with 0.6 uM rhodamine-conjugated phalloidin to stain for F-actin. Light and fluorescence micrographs were taken on fine-grained film. After photography, cells were further fixed in 2.5% GA, postfixed in 1% osmium, dehydrated in ethanol and embedded in Spurrs resin. The glass was removed by scoring with a diamond pencil followed by immersion in liquid N2. Cells were relocated in the blocks by phase-contrast microscopy. Thin (80 nm) sections were examined in Philips EM 410 at 60 kV on a dicentric goniometric stage.

A method of correlative light and electron microscopy for yeast cells

Micron ◽  
2014 ◽  
Vol 61 ◽  
pp. 53-61 ◽  
Author(s):  
Haruhiko Asakawa ◽  
Yasushi Hiraoka ◽  
Tokuko Haraguchi
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Yeast Cells

The Morphology of Vacuolated Cells in the Liver Following Administration of Vitamin A.

1973 ◽  
Vol 31 ◽  
pp. 408-409
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Electron Microscopy ◽  
Body Weight ◽  
Vitamin A ◽  
Light And Electron Microscopy ◽  
Liver Cells ◽  
Prominent Feature ◽  
Vascular Space ◽  
Vacuolated Cell ◽  
Vacuolated Cells ◽  
Vacuolated Cytoplasm

Vacuolated cells in the liver of young rats were studied by light and electron microscopy following the administration of vitamin A (200 units per gram of body weight). Their characteristics were compared with similar cells found in untreated animals.In rats given vitamin A, cells with vacuolated cytoplasm were a prominent feature. These cells were found mostly in a perisinusoidal location, although some appeared to be in between liver cells (Fig. 1). Electron microscopy confirmed their location in Disse's space adjacent to the sinusoid and in recesses between liver cells. Some appeared to be bordering the lumen of the sinusoid, but careful observation usually revealed a tenuous endothelial process separating the vacuolated cell from the vascular space. In appropriate sections, fenestrations in the thin endothelial processes were noted (Fig. 2, arrow).

Stereo Electron Microscopy Applied to High Resolution Freeze-Etch Replicas

1970 ◽  
Vol 28 ◽  
pp. 306-307
Author(s):  
L. Andrew Staehelin
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Resolution ◽  
Smooth Surfaces ◽  
Small Particles ◽  
Membrane Surfaces ◽  
Wide Acceptance ◽  
New Information ◽  
Number Of Particles ◽  
Small Holes

Freeze-etched membranes usually appear as relatively smooth surfaces covered with numerous small particles and a few small holes (Fig. 1). In 1966 Branton (1“) suggested that these surfaces represent split inner mem¬brane faces and not true external membrane surfaces. His theory has now gained wide acceptance partly due to new information obtained from double replicas of freeze-cleaved specimens (2,3) and from freeze-etch experi¬ments with surface labeled membranes (4). While theses studies have fur¬ther substantiated the basic idea of membrane splitting and have shown clearly which membrane faces are complementary to each other, they have left the question open, why the replicated membrane faces usually exhibit con¬siderably fewer holes than particles. According to Branton's theory the number of holes should on the average equal the number of particles. The absence of these holes can be explained in either of two ways: a) it is possible that no holes are formed during the cleaving process e.g. due to plastic deformation (5); b) holes may arise during the cleaving process but remain undetected because of inadequate replication and microscope techniques.

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