scholarly journals The Effect of 5-Fluorouracil on the Growth and Nucleolus of Wheat Coleoptiles

1970 ◽  
Vol 23 (3) ◽  
pp. 561 ◽  
Author(s):  
RJ Rose ◽  
Jeanette Gregory ◽  
FV Mercer
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Cell Elongation ◽  
Normal Cell ◽  
Light And Electron Microscopy ◽  
Wheat Coleoptile ◽  
Ribosome Synthesis ◽  
Cell Division Inhibition

Intact etiolated wheat coleoptiles grown from the beginning of imbibition III 5-fluorouracil (5-FU) show normal cell elongation, but division is inhibited. 5-FU-treated coleoptiles, 48 hr after imbibition, have enlarged nucleoli (165% increase in volume) in which the RNA is mostly confined to the periphery. Untreated and treated nucleoli were studied by light and electron microscopy. The 5-FU effects on the nucleolus, which occur at the time cell division usually occurs if 5-FU is not present, are of interest in relation to ribosome synthesis. Uracil or thymidine did not reverse the nucleolar effects, but uracil further inhibited growth, while thymidine partly reversed the cell division inhibition. Results with 5-FU and thymidine suggest that the coleoptile cells can divide at least once when they have abnormal nucleoli, but normal nucleolar metabolism is essential for the complete growth of the etiolated wheat coleoptile.

The effects of high hydrostatic pressure on microfilaments and microtubules in Xenopus laevis

Development ◽  
1978 ◽  
Vol 44 (1) ◽  
pp. 281-295
Author(s):  
Paul-Emil Messier ◽  
C. Seguin
Keyword(s):  
Electron Microscopy ◽  
Hydrostatic Pressure ◽  
Xenopus Laevis ◽  
Cell Elongation ◽  
High Hydrostatic Pressure ◽  
Light And Electron Microscopy ◽  
Duration Of Treatment ◽  
Neuroepithelial Cells ◽  
Exerted Pressure ◽  
Xenopus Laevis Embryos

Xenopus laevis embryos of stages 14–20 were subjected, for periods of 5–330 min, to hydrostatic pressures ranging from 500 to 10000 psi. The specimens were fixed under corresponding pressures and their neuroepithelium was studied under light and electron microscopy. A pressure of 3000 psi, maintained for as long as 180 min, did not inhibit neurulation though it induced slight deformities of the neuroepithelium. A pressure of 4000 psi, applied for 180 min, disrupted the apical ring of microfilaments and blocked neurulation. The cells lost their dissymmetry. The effect was reversible. Lengthening the duration of treatment to 330 min caused the neuroepithelial cells to loose their microtubules and to become round. This situation was not reversible. Our results indicated that microfilaments are more sensitive than microtubules, that both organelles became increasingly sensitive as the exerted pressure was increased and that microtubules of older embryos exhibited a better resistance. Finally, we showed a correlation between the presence of microfilaments and the constricted state of the cellular apices and a relationship between the presence of microtubules and cell elongation.

scholarly journals Atypical centrioles are present in Tribolium sperm

Open Biology ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 160334 ◽  
Author(s):  
E. L. Fishman ◽  
Kyoung Jo ◽  
Andrew Ha ◽  
Rachel Royfman ◽  
Ashtyn Zinn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drosophila Melanogaster ◽  
Cell Division ◽  
Tribolium Castaneum ◽  
Normal Cell ◽  
Somatic Cells ◽  
Red Flour Beetle ◽  
Flour Beetle ◽  
And Function

Typical centrioles are made of microtubules organized in ninefold symmetry. Most animal somatic cells have two centrioles for normal cell division and function. These centrioles originate from the zygote, but because the oocyte does not provide any centrioles, it is surprising that the zygotes of many animals are thought to inherit only one centriole from the sperm. Recently, in the sperm of Drosophila melanogaster , we discovered a second centriolar structure, the proximal centriole-like structure (PCL), which functions in the zygote. Whether the sperm of other insects has a second centriolar structure is unknown. Here, we characterized spermiogenesis in the red flour beetle, Tribolium castaneum . Electron microscopy suggests that Tribolium has one microtubule-based centriole at the tip of the axoneme and a structure similar to the PCL, which lacks microtubules and lies in a cytoplasmic invagination of the nucleus. Immunostaining against the orthologue of the centriole/PCL protein, Ana1, also recognizes two centrioles near the nucleus during spermiogenesis: one that is microtubule-based at the tip of the axoneme, suggesting it is the centriole; and another that is more proximal and appears during early spermiogenesis, suggesting it is the PCL. Together, these findings suggest that Tribolium sperm has one microtubule-based centriole and one microtubule-lacking centriole.

Correlative light and electron microscopy for the analysis of cell division

2013 ◽  
Vol 251 (2) ◽  
pp. 109-112 ◽  
Author(s):  
STEFANIE REDEMANN ◽  
THOMAS MÜLLER-REICHERT
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Light And Electron Microscopy

Correlated light and electron microscopy of cell division in large marine oocytes, eggs, and embryos

2018 ◽  
pp. 293-313 ◽  
Author(s):  
Mariia Burdyniuk ◽  
Natalia Wesolowska ◽  
Michal Fleszar ◽  
Matthia A. Karreman ◽  
Pedro Machado ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Light And Electron Microscopy

Morphology of the Toxin-Producing Diatom Nitzschia pungens Grunow forma multiseries Hasle

1992 ◽  
Vol 49 (2) ◽  
pp. 303-311 ◽  
Author(s):  
Daniel J. MacPhee ◽  
Louis A. Hanic ◽  
Dianne L. Friesen ◽  
David E. Sims
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Cell Motility ◽  
Prince Edward Island ◽  
Domoic Acid ◽  
Light And Electron Microscopy ◽  
Cell Ultrastructure ◽  
Field Samples ◽  
Toxic Blooms ◽  
Nitzschia Pungens

The toxin-producing diatom Nitzschia pungens Grunow forma multiseries Hasle from three toxic blooms in two Prince Edward Island estuaries, spanning 1987–89, was studied using light and electron microscopy. Cell ultrastructure of N. pungens is, in general, similar to that of other species of Nitzschia and other diatoms. Important features include prominent peripheral, polarized nucleoli (numbering one or two) and imperforate poroids, present on inner valves and girdle bands. Cell division is usually synchronous for all cells in a filament with respect to polarity and time. Postdivisional elongation of the filament appears to involve a "slide-by" process whereby sibling cells slide by each other along their opposed valve faces and then stop, becoming fused by their overlapping tips. The raphe is probably involved in this, as well as in filament and cell motility. Observations of particle motion along the cell raphe suggest the existence of a motility apparatus such as microcilia which would facilitate locomotion, intercellular coordination, and the postdivisional slide-by process. No bacteria or other organisms were observed associated with field samples of toxic N. pungens f. multiseries. This supports a view that domoic acid production is autonomous.

Morphogenetic analysis of changing cell associations following release of 2-cell and 4-cell mouse embryos from cleavage arrest

Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 331-345
Author(s):  
S. J. Kimber ◽  
M. A. H. Surani
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Light And Electron Microscopy ◽  
Cytochalasin D ◽  
Mouse Embryos ◽  
Fresh Medium ◽  
The Other ◽  
Similar Process ◽  
Serial Sections ◽  
Morphogenetic Analysis

Two-cell and four-cell mouse embryos were cultured in Cytochalasin D (CD) for 40–48 h. They were fixed for light and electron microscopy at various times after washing off the CD. Cleavage-arrested embiyos in CD had well separated blastomeres but by 1 h from washing the embryos had compacted, in most cases without undergoing cell division. By 2 h after release from arrest one blastomere of the 2-cell arrested embryos had become crescent shaped and at 4–5 h the crescent-shaped blastomere had started to spread over the surface of the other rounded blastomere. This process continued until by 16–24 h from explantation to fresh medium one blastomere had almost completely engulfed the other. A similar process occurred in 4-cell arrested and released embryos. At this stage the embryos had accumulated fluid and become blastocyst-like vesicles. In 20% of 2-cell and 4-cell embryos one or two blastomeres underwent one cell division after release from arrest. Serial sections of these embryos lead to the conclusion that one or both progeny of the first cell to divide tended to be engulfed by the later dividing or non-dividing cell(s). These results are discussed in relation to the differentiation of ICM and trophectoderm in blastocysts.

Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

1970 ◽  
Vol 28 ◽  
pp. 186-187
Author(s):  
Krishan Awtar
Keyword(s):  
Cell Division ◽  
Normal Cell ◽  
Virus Production ◽  
Multinucleate Cells ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Nuclear Membranes ◽  
Division 2 ◽  
Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

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).

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.

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