Ultrastructural localization of nucleolar organizers during oogenesis in Xenopus laevis using a silver technique

1984 ◽  
Vol 65 (1) ◽  
pp. 73-93
Author(s):  
M. Boloukhere
Keyword(s):  
Xenopus Laevis ◽  
Transcriptional Activity ◽  
Morphological Changes ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Electron Microscopic Level ◽  
Xenopus Laevis Oocytes ◽  
Electron Microscopic ◽  
Nucleolar Activity ◽  
Nucleolar Organizers

Silver staining at the electron microscopic level of the nucleolar organizers was carried out on Xenopus laevis oocytes at various stages of oogenesis. The results indicate that a positive reaction takes place exclusively in the dense fibrillar component of the extrachromosomal nucleoli. This constituent undergoes morphological changes of distribution and architecture, which have been correlated with modifications of the transcriptional activity of the nucleoli. When nucleolar activity is reduced, during previtellogenesis, this constituent appears as dense homogeneous spherules well-segregated from the granular component. In contrast, when nucleolar activity is high, during vitellogenesis, it forms an heterogeneous area with an ill-delimited outline: it is organized into a fibrillar core with emerging skein-like strings. It thus seems that this constituent remains silver-stained throughout oogenesis. These findings suggest that the method used would allow one to follow the evolution of the nucleolar organizer region (NOR) topography during oogenesis. Moreover, they point out facts that have relevance to the problem of the correlation between Ag stainability of NORs and nucleolar transcriptional activity.

scholarly journals PREGNANCY, COMPLICATED BY PREECLAMPSIA: FETOPLACENTAL COMPLEX IMMUNE DEADAPTATION AND HISTOSTRUCTURAL FEATURES

2020 ◽  
Vol 73 (1) ◽  
pp. 99-103
Author(s):  
Pavlo V. Yavorskyi ◽  
Vitalii M. Zozulia ◽  
Oleh Ya. Vanchuliak ◽  
Marta S. Garazdiuk
Keyword(s):  
Pregnant Women ◽  
Transforming Growth Factor ◽  
Morphological Changes ◽  
Immunohistochemical Method ◽  
Electron Microscopic Level ◽  
Control Group ◽  
Electron Microscopic ◽  
Correlation Relationship ◽  
Uncomplicated Pregnancy ◽  
Fetoplacental Complex

The aim: to study and compare the features of the interleukins levels and morphological changes of placenta at various stages of preeclampsia. Materials and methods: 109 pregnant women with preeclampsia of varying severity (study group) and 30 pregnant women with uncomplicated pregnancy (control group) were examined. Immunohistochemical method, proinflammatory interleukins levels, morphological and morphometric analysis of peripheral and central placental areas biopsies on the optical and electron-microscopic level have been used. Results: Morphofunctional changes in the placenta in case of preeclampsia and the increase in the expression level of the transforming growth factor have a series of regular stages from the formation, strain and disruption of adaptive mechanisms with more pronounced signs of morphological immaturity of parenchymal and stromal elements of the placenta, especially in the area of syncytiotrophoblast and spiral vessels. The degree of clinical manifestation of preeclampsia has a correlation relationship with IL-10 deficiency and with the increase in TNF-α, stimulation of macrophage-protein production that contributes to the change in the ratio of Thl / Th2, which are antagonists and inhibit each other’s development. Conclusions: The severity of the preeclampsia course correlates with the state of morphofunctional changes in the placenta and changes in the ratio of the pro- and anti-inflammatory interleukins.

Ultrastructural morphology of cells transformed with temperature-sensitive mutant of Mo-MuSV

1989 ◽  
Vol 47 ◽  
pp. 1076-1077
Author(s):  
F. Al-Bagdadi ◽  
B. Singh ◽  
R.B. Arlinghaus
Keyword(s):  
Morphological Changes ◽  
Calf Serum ◽  
Cellular Transformation ◽  
Uranyl Acetate ◽  
Abnormal Behavior ◽  
Electron Microscopic Level ◽  
Temperature Sensitive ◽  
Electron Microscopic ◽  
Sensitive Mutant ◽  
Temperature Sensitive Mutant

It is known that one of the abnormal behavior of cancer cells is changes in morphology. There is very little information in the literature on the morphological aspects of cell lines at the electron microscopic level transformed by viral mos gene (Culp, 1971; Hynes et al., 1978; Brown et al., 1981; Arlinghaus, 1985; Terasaki et al., 1986). NRK-6m2 is a cell line infected with a temperature sensitive mutant (tsll0) of Moloney murine sarcoma virus (Arlinghaus, 1985). The attempt in this study is to examine the ultrastructure of NRK-6m2 cells and relate the morphological changes to gag-mos induced cellular transformation.NRK-6m2 cell cultures were maintained in McCoy's 5a medium supplemented with 15% fetal calf serum. Subconfuluent cells were washed twice in cold phosphate buffered saline and fixed in situ in 1% glutaraldehyde, scraped and centrifuged at 1500 g for 5 min at 4°C, post fixed in osmium tetroxided and processed for electron microscopic study. Silver sections were stained with uranyl acetate and lead citrate and examined on a Joel 1200 EX electron microscope.

Pattern of nucleolar organizer region activity during male meiosis in Callicrania seoanei (Orthoptera) as analyzed by silver staining: evidences for a possible reactivation in the period between the two meiotic divisions

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 516-518 ◽  
Author(s):  
J. Santos ◽  
C. Sentis ◽  
J. Fernandez-Piqueras
Keyword(s):  
Key Words ◽  
Silver Staining ◽  
Transcriptional Activity ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Male Meiosis ◽  
Positive Material ◽  
Ribosomal Cistrons ◽  
Early Spermatid

Silver staining of spermatocytes and early spermatid nuclei from the neo XY race of the Tettigonioid species Callicrania seoanei reveals an active nucleolar organizer region (NOR) located proximally in a medium-sized bivalent. Ag-positive material was present at the NOR in all stages of male meiosis. However, the results obtained indicate that transcriptional activity of ribosomal cistrons (rDNA) is not maintained throughout spermatogenesis, but that NOR reactivation might occur in the period between the two meiotic divisions in addition to the more general postmeiotical reactivation in the early spermatid nuclei. Key words: NOR activity, silver staining, male meiosis, Callicrania seoanei (Orthoptera).

scholarly journals Subcellular Localization of the TFF Peptides xP1 and xP4 in the Xenopus laevis Gastric/Esophageal Mucosa: Different Secretion Modes Reflecting Diverse Protective Functions

2020 ◽  
Vol 21 (3) ◽  
pp. 761 ◽  
Author(s):  
Heinz Schwarz ◽  
Werner Hoffmann
Keyword(s):  
Xenopus Laevis ◽  
Secretory Granules ◽  
Lectin Binding ◽  
Goblet Cells ◽  
Electron Microscopic Level ◽  
Esophageal Mucosa ◽  
Mucous Cells ◽  
Electron Microscopic ◽  
Gastric Mucous ◽  
Tff Peptides

The TFF peptides xP1 and xP4 from Xenopus laevis are orthologs of TFF1 and TFF2, respectively. xP1 is secreted as a monomer from gastric surface mucous cells and is generally not associated with mucins, whereas xP4 is a typical secretory peptide from esophageal goblet cells, and gastric mucous neck and antral gland cells tightly associated as a lectin with the ortholog of mucin MUC6. Both TFF peptides have diverse protective functions, xP1 as a scavenger for reactive oxygen species preventing oxidative damage and xP4 as a constituent of the water-insoluble adherent inner mucus barrier. Here, we present localization studies using immunofluorescence and immunoelectron microscopy. xP1 is concentrated in dense cores of secretory granules of surface mucous cells, whereas xP4 mixes with MUC6 in esophageal goblet cells. Of note, we observe two different types of goblet cells, which differ in their xP4 synthesis, and this is even visible morphologically at the electron microscopic level. xP4-negative granules are recognized by their halo, which is probably the result of shrinkage during the processing of samples for electron microscopy. Probably, the tight lectin binding of xP4 and MUC6 creates a crosslinked mucous network forming a stabile granule matrix, which prevents shrinkage.

Ultrastructure and the relationship between the nucleolus and the nucleolar organizer region in Orthoptera male germ cells

1985 ◽  
Vol 27 (2) ◽  
pp. 186-191 ◽  
Author(s):  
P. Esponda ◽  
J. S. Rufas ◽  
S. Fonzo ◽  
J. Gosálvez
Keyword(s):  
Germ Cells ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Serial Sections ◽  
Male Germ Cells ◽  
Fibrillar Center ◽  
Nucleolar Organizers ◽  
The Relationship

The ultrastructure of the nucleolus and the nucleolar organizer region, together with the relationships they maintain, are described in male germ cells of two species of grasshoppers. The nucleolus is multiple and appears related to a fibrillar center which seems to represent only a nontranscribing part of the organizer region. By means of serial sections, a particular relationship among the fibrillar center, the rDNA loops, and the nucleolar masses is suggested.Key words: ultrastructure, nucleolar organizers, nucleolus, Orthoptera.

Silver Staining of Pancreatic Islets as Revealed by Electron Microscopy

1967 ◽  
Vol 25 ◽  
pp. 44-45
Author(s):  
Kazuaki Misugi ◽  
Nobuko Misugi ◽  
Hiroshi Yamada
Keyword(s):  
Pancreatic Islet ◽  
Silver Staining ◽  
Islet Cells ◽  
Severe Hypoglycemia ◽  
Granular Cell ◽  
Electron Microscopic Level ◽  
Staining Reaction ◽  
Electron Microscopic ◽  
Pancreatic Islet Cell ◽  
D Cell

The authors had described the fine structure of a type of pancreatic islet cell, which appeared different from typical alpha and beta cells, and tentatively considered that this third type of granular cell probably represents the D cell (Figure 1).Since silver staining has been widely used to differentiate different types of pancreatic islet cells by light microscopy, an attempt to examine this staining reaction at the electron microscopic level was made.Material and Method: Surgically removed specimens from three infants who suffered from severe hypoglycemia were used. The specimens were fixed and preserved in 20% neutral formalin. Frozen sections, 30 to 40 micron thick, were prepared and they were stained by Bielschowsky's method as modified by Suzuki (2). The stained sections were examined under a microscope and islet tissues were isolated. They were fixed in 1% osmium tetroxide in phosphate buffer for one hour and embedded in Epon 812 following dehydration through a series of alcohols and propylene oxide.

A simplified method of emulsion coating and development for quantitative electron microscopic radioautography

1978 ◽  
Vol 36 (2) ◽  
pp. 64-65
Author(s):  
K. Yoshida ◽  
F. Murata ◽  
S. Ohno ◽  
T. Nagata
Keyword(s):  
Mass Production ◽  
Identical Condition ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Simplified Method ◽  
Complicated Process ◽  
Critical Problems ◽  
Electron Microscopic Radioautography ◽  
Quantitative Radioautography

IntroductionSeveral methods of mounting emulsion for radioautography at the electron microscopic level have been reported. From the viewpoint of quantitative radioautography, however, there are many critical problems in the procedure to produce radioautographs. For example, it is necessary to apply and develop emulsions in several experimental groups under an identical condition. Moreover, it is necessary to treat a lot of grids at the same time in the dark room for statistical analysis. Since the complicated process and technical difficulties in these procedures are inadequate to conduct a quantitative analysis of many radioautographs at once, many factors may bring about unexpected results. In order to improve these complicated procedures, a simplified dropping method for mass production of radioautographs under an identical condition was previously reported. However, this procedure was not completely satisfactory from the viewpoint of emulsion homogeneity. This paper reports another improved procedure employing wire loops.

Hydrated form of some clay minerals observed using a film sealed environmental cell

1978 ◽  
Vol 36 (1) ◽  
pp. 72-73
Author(s):  
N. Kohyama ◽  
K. Fukushima ◽  
A. Fukami
Keyword(s):  
Clay Minerals ◽  
Morphological Changes ◽  
Carbon Film ◽  
Electron Microscopic Observation ◽  
Adsorbed Water ◽  
Electron Microscopic ◽  
Hydrated Form ◽  
Thin Carbon ◽  
Environmental Cell ◽  
Thin Carbon Film

Since the interlayer or adsorbed water of some clay minerals are quite easily dehydrated in dried air, in vacuum, or at moderate temperatures even in the atmosphere, the hydrated forms have not been observed by a conventional electron microscope(TEM). Recently, specific specimen chambers, “environmental cells(E.C.),” have been developed and confirmed to be effective for electron microscopic observation of wet specimen without dehydration. we observed hydrated forms of some clay minerals and their morphological changes by dehydration using a TEM equipped with an E.C..The E.C., equipped with a single hole copper-microgrid sealed by thin carbon-film, attaches to a TEM(JEM 7A) with an accelerating voltage 100KV and both gas pressure (from 760 Torr to vacuum) and relative humidity can be controlled. The samples collected from various localities in Japan were; tubular halloysite (l0Å) from Gumma Prefecture, sperical halloysite (l0Å) from Tochigi Pref., and intermediate halloysite containing both tubular and spherical types from Fukushima Pref..

A New Technique for the Light and Electron Microscopic Study of Individual Cerebro-Spinal Fluid Cells in a Mona Plane Layer

1976 ◽  
Vol 34 ◽  
pp. 362-363
Author(s):  
L.A. Dell
Keyword(s):  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Plane Layer ◽  
Ultrastructural Level ◽  
Spinal Fluid ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Easy Method ◽  
Cell Pellet ◽  
A New Technique

A new method has been developed which readily offers the microscopist a possibility for both light and electron microscopic study of selected cells from the cerebrospinal fluid. Previous attempts to examine these cells in the spinal fluid at the ultrastructural level were based on modifications of cell pellet techniques developed for peripheral blood. These earlier methods were limited in application by the number of cells in spinal fluid required to obtain a sufficient size pellet and by the lack of an easy method of cellular identification between the light and electron microscopic level. The newly developed method routinely employs microscope slides coated with Siliclad and tungsten oxide for duplicate cytocentrifuge preparations of diagnostic spinal fluid specimens. Work done by Kushida and Suzuki provided a basis for our use of the metal oxide.

Electron Microscopic Analysis of Myonecrosis Induced by a Pure Component Isolated From Rattlesnake Venom

1976 ◽  
Vol 34 ◽  
pp. 292-293
Author(s):  
Charlotte L. Ownby ◽  
David Cameron ◽  
Anthony T. Tu
Keyword(s):  
Gel Filtration ◽  
Microscopic Analysis ◽  
The United States ◽  
Exchange Chromatography ◽  
Pure Component ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Mouse Muscle ◽  
Major Health Problem ◽  
Rattlesnake Venom

In the United States the major health problem resulting from snakebite poisoning is local tissue damage, i.e. hemorrhage and myonecrosis. Since commercial antivenin does not usually prevent such damage to tissue, a more effective treatment of snakebite-induced myonecrosis is needed. To aid in the development of such a treatment the pathogenesis of myonecrosis induced by a pure component of rattlesnake venom was studied at the electron microscopic level.The pure component, a small (4,300 mol. wt.), basic (isoelectric point of 9.6) protein, was isolated from crude prairie rattlesnake (Crotalus viridis viridis) venom by gel filtration (Sephadex G-50) followed by cation exchange chromatography (Sephadex C-25), and shown to be pure by electrophoresis. Selection of the myotoxic component was based on light microscopic observations of injected mouse muscle.

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