The ultrastructure and taxonomy of Rhizochromulina marina gen. et sp.nov., an amoeboid marine chrysophyte

1979 ◽  
Vol 59 (1) ◽  
pp. 179-193 ◽  
Author(s):  
David J. Hibberd ◽  
Marie-Josèphe Chretiennot-Dinet
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Motile Cell ◽  
Vegetative Cells ◽  
Cell Organization

A new member of the Chrysophyceae, Rhizochromulina marina gen. et sp.nov. is described by means of both light and electron microscopy of cultured material. Vegetative cells are non-flagellate and amoeboid with many fine beaded filipodia and a single golden-brown chloroplast. Zoospores are fusiform in shape and genuinely uniflagellate with no emergent vestigial second flagellum. They appear to possess the most reduced and phylogenetically advanced type of motile cell organization yet found in the Chrysophyceae.

A Reinvestigation by Light and Electron Microscopy of Ruttnera Spectabilis Geitler (Haptophyceae), with Special Reference to the Fine Structure of the Zoids

1974 ◽  
Vol 54 (3) ◽  
pp. 539-550 ◽  
Author(s):  
J. C. Green ◽  
Mary Parke
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Special Reference ◽  
Light And Electron Microscopy ◽  
Vegetative Cells ◽  
Freshwater Habitats ◽  
Systematic Relationships

Within the Chromophyta (sensu Christensen, 1962) a number of genera having benthic phases in which the vegetative cells are embedded in masses of thick, sometimes stratified mucilage, have been described from both marine and freshwater habitats. Examples include Gloeochrysis Pasch. (Pascher, 1925), Geochrysis Pasch. (Pascher, 1931), Sarcinochrysis Geitl. (Geitler, 1930), Chrysotila Anand (Anand, 1937) and Ruttnera Geitl. (Geitler, 1942). In many cases the vegetative stages are so similar morphologically as to be almost indistinguishable, especially in the juvenile condition in which the cells are often arranged in regular blocks (the ‘Sarcinochrysis’ condition) and under such circumstances it is difficult to ascertain their true systematic relationships.

scholarly journals Imaging Viral Factories

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 3
Author(s):  
Cristina Risco Ortiz
Keyword(s):  
Electron Microscopy ◽  
Viral Replication ◽  
Molecular Mapping ◽  
Light And Electron Microscopy ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Particle Assembly ◽  
Intracellular Compartments ◽  
Cell Organization ◽  
Viral Lifecycle

Viruses remodel cellular compartments to build their replication factories. Remarkably, viruses are also able to induce new membranes and new organelles. As a result of recent advances in light and transmission electron microscopy (TEM), we are starting to become aware of the variety of structures that viruses assemble inside cells. Viral factories are intracellular compartments harboring replication organelles that contain viral replication complexes and the sites of virus particle assembly. This lecture will revise the most relevant imaging technologies for studying the biogenesis of viral replication factories. Live cell microscopy, correlative light and electron microscopy, cryo-TEM, and three-dimensional imaging methods are unveiling how viruses manipulate cell organization. In particular, methods for molecular mapping in situ, in two and three dimensions, are revealing how macromolecular complexes build functional replication complexes inside infected cells. The combination of all these imaging approaches is uncovering the viral lifecycle events with a detail never seen before.

scholarly journals More than meets the eye: regional specialisation and microbial cover of the blade of Porphyra umbilicalis (Bangiophyceae, Rhodophyta)

2018 ◽  
Vol 61 (5) ◽  
pp. 459-465 ◽  
Author(s):  
Charlotte J. Royer ◽  
Nicolas A. Blouin ◽  
Susan H. Brawley
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Filamentous Cyanobacteria ◽  
Vegetative Cells ◽  
Ongoing Research ◽  
Porphyra Umbilicalis ◽  
Floridean Starch ◽  
Regional Specialisation

Abstract Completion of the Porphyra umbilicalis genome and ongoing research on this species by many investigators suggest the need for wider appreciation of regional specialisation of the P. umbilicalis blade. Here we use light and electron microscopy to describe four distinct regions of the blade: rhizoid cells with abundant floridean starch, vegetative cells, differentiating neutral sporangia, and mature neutral spores. The holdfast, densely covered by microorganisms, presents an intriguing biomechanical structure: thousands of very thin, long rhizoid tips course through the thick, secreted polysaccharide to the substratum. Wild blades in culture have more microorganisms than when collected, including filamentous cyanobacteria.

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).

A Resorcinol-Formaldehyde Resin as an Embedding Material for Electron Microscopy of Membranes

1969 ◽  
Vol 27 ◽  
pp. 328-329 ◽  
Author(s):  
J. G. Robertson ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Osmium Tetroxide ◽  
Neutral Lipids ◽  
Lipid Extraction ◽  
Water Soluble ◽  
Formaldehyde Resin ◽  
Electron Microscope Autoradiography ◽  
Resorcinol Formaldehyde ◽  
Major Disadvantage ◽  
Cell Organization

The extraction of lipids from tissues during fixation and embedding for electron microscopy is widely recognized as a source of possible artifact, especially at the membrane level of cell organization. Lipid extraction is also a major disadvantage in electron microscope autoradiography of radioactive lipids, as in studies of the uptake of radioactive fatty acids by intestinal slices. Retention of lipids by fixation with osmium tetroxide is generally limited to glycolipids, phospholipids and highly unsaturated neutral lipids. Saturated neutral lipids and sterols tend to be easily extracted by organic dehydrating reagents prior to embedding. Retention of the more saturated lipids in embedded tissue might be achieved by developing new cross-linking reagents, by the use of highly water soluble embedding materials or by working at very low temperatures.

Control of Autogenous Vein Grafts Prior to Reimplantation, By Electron Microscopy

1972 ◽  
Vol 30 ◽  
pp. 106-107
Author(s):  
John H. L. Watson ◽  
John L. Swedo ◽  
M. Vrandecic
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Physiological Saline ◽  
Experimental Conditions ◽  
Vein Grafts ◽  
Arterial Blood ◽  
Saphenous Veins ◽  
Autogenous Vein ◽  
Control Of Parameters ◽  
Post Implantation

The ambient temperature and the nature of the storage fluids may well have significant effects upon the post-implantation behavior of venus autografts. A first step in the investigation of such effects is reported here. Experimental conditions have been set which approximate actual operating room procedures. Saphenous veins from dogs have been used as models in the experiments. After removal from the dogs the veins were kept for two hours under four different experimental conditions, viz at either 4°C or 23°C in either physiological saline or whole canine arterial blood. At the end of the two hours they were prepared for light and electron microscopy. Since no obvious changes or damage could be seen in the veins by light microscopy, even with the advantage of tissue specific stains, it was essential that the control of parameters for successful grafts be set by electron microscopy.

Ultrastructure of two neoplasms in culture compared with original biopsies

1984 ◽  
Vol 42 ◽  
pp. 50-51
Author(s):  
Joseph M. Harb ◽  
James T. Casper ◽  
Vlcki Piaskowski
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Biopsy Specimen ◽  
Cultured Cells ◽  
Light And Electron Microscopy ◽  
Human Tumor ◽  
Soft Agar ◽  
Human Tumor Cells ◽  
Morphological Distinction ◽  
Tumor Types

The application of tissue culture and the newer methodologies of direct cloning and colony formation of human tumor cells in soft agar hold promise as valuable modalities for a variety of diagnostic studies, which include morphological distinction between tumor types by electron microscopy (EM). We present here two cases in which cells in culture expressed distinct morphological features not apparent in the original biopsy specimen. Evaluation of the original biopsies by light and electron microscopy indicated both neoplasms to be undifferentiated sarcomas. Colonies of cells propagated in soft agar displayed features of rhabdomyoblasts in one case, and cultured cells of the second biopsy expressed features of Ewing's sarcoma.

The Effect of Vitamin A on the Intermittent Nitrogen Dioxide Gas Exposure in Hamsters

1976 ◽  
Vol 34 ◽  
pp. 176-177
Author(s):  
J.C.S. Kim ◽  
M.G. Jourden ◽  
E.S. Carlisle
Keyword(s):  
Electron Microscopy ◽  
Vitamin A ◽  
Nitrogen Dioxide ◽  
Chronic Exposure ◽  
Light And Electron Microscopy ◽  
Specific Effect ◽  
Deficient Diet ◽  
Intermittent Exposure ◽  
Hypovitaminosis A ◽  
Gas Exposure

Chronic exposure to nitrogen dioxide in rodents has shown that injury reaches a maximum after 24 hours, and a reparative adaptive phase follows (1). Damage occurring in the terminal bronchioles and proximal portions of the alveolar ducts in rats has been extensively studied by both light and electron microscopy (1).The present study was undertaken to compare the response of lung tissue to intermittent exposure to 10 ppm of nitrogen dioxide gas for 4 hours per week, while the hamsters were on a vitamin A deficient diet. Ultrastructural observations made from lung tissues obtained from non-gas exposed, hypovitaminosis A animals and gas exposed animals fed a regular commercially prepared diet have been compared to elucidate the specific effect of vitamin A on nitrogen dioxide gas exposure. The interaction occurring between vitamin A and nitrogen dioxide gas has not previously been investigated.

mRNA localization by Electron microscopic in situ hybridization

1991 ◽  
Vol 49 ◽  
pp. 430-431
Author(s):  
J. A. Pollock ◽  
M. Martone ◽  
T. Deerinck ◽  
M. H. Ellisman
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Nucleic Acids ◽  
Recombinant Dna ◽  
Light And Electron Microscopy ◽  
Electron Microscopic ◽  
High Voltage Electron Microscopy ◽  
Functional Sites ◽  
Voltage Electron

Localization of specific proteins in cells by both light and electron microscopy has been facilitate by the availability of antibodies that recognize unique features of these proteins. High resolution localization studies conducted over the last 25 years have allowed biologists to study the synthesis, translocation and ultimate functional sites for many important classes of proteins. Recently, recombinant DNA techniques in molecular biology have allowed the production of specific probes for localization of nucleic acids by “in situ” hybridization. The availability of these probes potentially opens a new set of questions to experimental investigation regarding the subcellular distribution of specific DNA's and RNA's. Nucleic acids have a much lower “copy number” per cell than a typical protein, ranging from one copy to perhaps several thousand. Therefore, sensitive, high resolution techniques are required. There are several reasons why Intermediate Voltage Electron Microscopy (IVEM) and High Voltage Electron Microscopy (HVEM) are most useful for localization of nucleic acids in situ.

The Response of Testis Cells to Low Dose X-Irradiation

1981 ◽  
Vol 39 ◽  
pp. 542-543
Author(s):  
D. E. Philpott ◽  
W. Sapp ◽  
C. Williams ◽  
Joann Stevenson ◽  
S. Black
Keyword(s):  
Electron Microscopy ◽  
Stem Cell ◽  
Light Microscopy ◽  
Dose Level ◽  
Cross Sections ◽  
Low Dose ◽  
Light And Electron Microscopy ◽  
Cellular Responses ◽  
Post Irradiation ◽  
X Irradiation

The response of spermatogonial cells to X-irradiation is well documented. It has been shown that there is a radiation resistent stem cell (As) which, after irradiation, replenishes the seminiferous epithelium. Most investigations in this area have dealt with radiation dosages of 100R or more. This study was undertaken to observe cellular responses at doses less than 100R of X-irradiation utilizing a system in which the tissue can be used for light and electron microscopy.Brown B6D2F1 mice aged 16 weeks were exposed to X-irradiation (225KeV; 15mA; filter 0.35 Cu; 50-60 R/min). Four mice were irradiated at each dose level between 1 and 100 rads. Testes were removed 3 days post-irradiation, fixed, and embedded. Sections were cut at 2 microns for light microscopy. After staining, surviving spermatogonia were identified and counted in tubule cross sections. The surviving fraction of spermatogonia compared to control, S/S0, was plotted against dose to give the curve shown in Fig. 1.

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