scholarly journals Involvement of contractile proteins in the changes in consistency of oocyte nucleoplasm of the newt Pleurodeles waltlii.

1981 ◽  
Vol 88 (2) ◽  
pp. 410-421 ◽  
Author(s):  
P Gounon ◽  
E Karsenti
Keyword(s):  
Electron Microscope ◽  
Oocyte Nucleus ◽  
Immunoperoxidase Technique ◽  
Actin Microfilaments ◽  
Nuclear Actin ◽  
Filamentous Form ◽  
Associated Proteins ◽  
Pleurodeles Waltlii ◽  
Indirect Immunoperoxidase ◽  
Actin Cables

In the present work, we show that actin is present in considerable quantities in the oocyte nucleus of the newt Pleurodeles waltlii. The nuclear sap, extracted in saline buffer containing Ca++, is fluid. DNAase I inhibition assays have shown that 90% of actin is under a globular state in such conditions. Chelation of Ca++ by EGTA leads to the formation of a nuclear gel composed of individual microfilaments. This nuclear gel contains approximately 50% of total nuclear actin in a filamentous form. Phalloidin, a drug known to stabilize F-actin, induces the formation of a network of actin cables in the nuclei. This network contains nearly 100% of total nuclear actin in the filamentous form. The observation of the cables in the electron microscope shows that they are made of tightly associated microfilaments to which RNP-like particles are bound. The actin antibodies stain the cables and the particles by the indirect immunoperoxidase technique; myosin antibodies mainly stain the particles. The formation of the phalloïdin-induced network seems to require the presence of Ca++, Mg++, and ATP. We propose a scheme for the regulation of the supramolecular forms of actin in oocyte nuclei in which a delicate equilibrium seems to exist between globular actin, microfilaments, and actin cables. This equilibrium would be controlled by the concentration of Ca++, ATP, and various actin-associated proteins.

scholarly journals Varicella-zoster plaque assay and plaque reduction neutralization test by the immunoperoxidase technique

1976 ◽  
Vol 4 (5) ◽  
pp. 437-442
Author(s):  
G Gerna ◽  
R W Chambers
Keyword(s):  
Neutralization Test ◽  
Plaque Assay ◽  
Neutralizing Antibody ◽  
Immunoperoxidase Technique ◽  
Serum Samples ◽  
Plaque Reduction Neutralization Test ◽  
Varicella Zoster ◽  
Convalescent Phase ◽  
Antibody Titers ◽  
Indirect Immunoperoxidase

A new plaque assay for the quantitation of varicella-zoster virus and a plaque reduction neutralization test for the determination of neutralizing antibody titer have been developed using the indirect immunoperoxidase technique. As compared with the classical plaque assay using a solid overlay, the test gives earlier results since plaque counting can be performed on day 3 after the inoculation of cell cultures. In six patients with zoster infection, neutralizing antibody titers ranged from 1:20 to 1:40 before the onset of infection and reached high levels (1:320 to 1:5,120) during the convalescent phase of the disease. Complement-fixing (CF) titers were all negative (less than 1:8) in prezoster serum samples from the same patients and ranged from 1:128 to 1:2,048 in the convalescent-phase sera. In the two cases in which late serum samples were available, neutralizing antibody titers matched the preillness levels, whereas CF titers dropped to undetectable levels. Neither neutralizing nor CF antibody was detected in two sera from individuals with no history of varicella-zoster infection. No differences in virus titers or neutralizing antibody titers were observed between the immunoperoxidase and the classical plaque assays. The appropriate characterization of reagent specificity is required before routine application of the test.

scholarly journals Association of nucleoplasmin with transcription products as revealed by immunolocalization in the amphibian oocyte.

1986 ◽  
Vol 103 (3) ◽  
pp. 683-690 ◽  
Author(s):  
N Moreau ◽  
N Angelier ◽  
M L Bonnanfant-Jais ◽  
P Gounon ◽  
P Kubisz
Keyword(s):  
Transcriptional Activity ◽  
Light And Electron Microscopy ◽  
Nuclear Proteins ◽  
Oocyte Nucleus ◽  
Actin Network ◽  
Previously Treated ◽  
Pleurodeles Waltlii ◽  
Chromosome Axis ◽  
Lampbrush Loops ◽  
Nuclear Content

The oocyte nucleus of Pleurodeles waltlii contains a major 32,000-mol-wt acidic protein which is called nucleoplasmin. Rabbit antibodies were raised against total nuclear proteins from Pleurodeles oocytes. Affinity-purified antibodies directed against nucleoplasmin were prepared using antigens bound to nitrocellulose paper. The specificity of the antibody was controlled on two-dimensional electrophoretic gels of nuclear proteins. The intranuclear distribution of nucleoplasmin was analyzed by indirect immunofluorescence and the immunogold technique in light and electron microscopy. The antibody was tested on a spread of the nuclear content prepared in the presence of calcium, on the nuclear content spread in the presence of phalloidin so that an actin network appeared, and on a spread of nuclei from oocytes previously treated by actinomycin D. In all cases, nucleoplasmin appeared to be localized on the lampbrush loops, i.e., on the sites of transcription and, more specifically, on the ribonucleoprotein (RNP) particles; this protein was also associated with the RNP particles of the nuclear sap (free or inserted in the actin network). Nucleoplasmin was localized on large RNP particles that appeared when transcription was blocked. We never found this protein on the chromosome axis. These results suggest that nucleoplasmin may play a role in transcriptional activity.

scholarly journals STRUCTURE AND DEVELOPMENT OF VIRUSES OBSERVED IN THE ELECTRON MICROSCOPE

1956 ◽  
Vol 104 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Councilman Morgan ◽  
Harry M. Rose ◽  
Dan H. Moore
Keyword(s):  
Cell Wall ◽  
Free Surface ◽  
Electron Microscope ◽  
Chorioallantoic Membrane ◽  
Outer Coat ◽  
Spherical Form ◽  
Filamentous Form ◽  
Viral Particles ◽  
Constant Distance ◽  
Infectious Unit

Rods and spheres believed to represent viral particles were observed at the free surface of entodermal cells of the chorioallantoic membrane 6 to 44 hours after infection. Although occasional short rods revealed poorly defined internal bodies, the majority, as well as all the longer rods (filaments), exhibited no visible internal structure. The spheres presumed to lie central to the plane of section contained an inner body 20 to 22 mµ in diameter. Both forms possessed a dense, sharply defined limiting membrane 30 A thick and a diffuse external coat of lesser density. Where superimposition within the section was minimal, the viral particles were separated by a relatively constant distance. Measured to include this spacing, on the assumption that it reflected the presence of a component of the outer coat, the diameters of a majority of the rods were 50 to 60 mµ, whereas the spheres averaged 60 to 70 mµ. The rods appeared to form by a process of extrusion from the cell wall and became detached either singly or in bundles of variable length. The spheres seemed to differentiate at the cell surface and to acquire the inner body, limiting membrane, and outer coat as they migrated through the membrane of the host cell. No characteristic changes were seen in the nuclei or adjacent cytoplasm, and recognizable viral particles were never encountered in these areas of the cell. No support was obtained for the assumption that the spheres developed primarily by segmentation of the rods. It is suggested that the spherical form of the virus is the elemental infectious unit and that the filamentous form is largely or completely non-infective.

scholarly journals Nuclear actin cable with multiple branches during yeast meiosis

2019 ◽  
Author(s):  
Tomoko Takagi ◽  
Masako Osumi ◽  
Akira Shinohara
Keyword(s):  
Meiotic Prophase ◽  
Electron Microscopic Observation ◽  
Yeast Cells ◽  
Rectangular Lattice ◽  
Nuclear Actin ◽  
Electron Microscopic ◽  
Prophase I ◽  
Meiotic Prophase I ◽  
Actin Cable ◽  
Actin Cables

AbstractActin polymerizes to form filaments/cables for motility, transport, and structural framework in a cell. Recent studies show that actin polymers are present not only in cytoplasm, but also in nuclei of vertebrate cells, and their formation is induced in response to stress. Here, by electron microscopic observation with rapid freezing and high-pressure freezing, we found a unique polymerized form of actin inside of nuclei of budding yeast cells undergoing meiosis. The nuclear actin cable during meiosis consists of several actin filaments with a rectangular lattice arrangement and is associated with multiple branched cables/filaments showing “feather-like” appearance. The cable is immuno-labeled with anti-actin antibody and sensitive to an actin-depolymerizing drug. Like cytoplasmic actin cables, nuclear actin cables are rarely seen in pre-meiotic cells and spores, and are induced during meiotic prophase-I. We speculate that nuclear actin cables play a role in nuclear events during meiotic prophase I.

Use of a Pool of Monoclonal Antibodies in Diagnosing Cells from Serous Cavities

1993 ◽  
Vol 79 (3) ◽  
pp. 211-213
Author(s):  
Antonio Cappellari ◽  
Mariangela Bagarella ◽  
Sylvie Ménard ◽  
Marcella Calabrese ◽  
Maria Ines Colnaghi
Keyword(s):  
Monoclonal Antibodies ◽  
Traditional Method ◽  
Immunoperoxidase Technique ◽  
Malignant Cells ◽  
Lung Cancers ◽  
Epithelial Origin ◽  
Neoplastic Lesions ◽  
Immunocytochemical Method ◽  
Indirect Immunoperoxidase ◽  
Diagnostic Investigations

Aims and Background The usefulness of monoclonal antibodies that recognize markers of neoplastic lesions in complementing conventional cytology was evaluated by the avidin-biotin-peroxidase complex, indirect immunoperoxidase technique. Methods In order to enhance the sensitivity of the traditional method, a pool of seven combined monoclonal antibodies (Pool C7), which reacts specifically with cells of epithelial origin and is able to distinguish between mesothelial and malignant cells, was tested on cytologic smears of 262 serous effusions. The effusions were benign or neoplastic, mainly from breast, ovary and lung cancers. Results Immunocytochemical method showed an 100 % specificity and 100 % of predictivity whereas the sensitivity was 98 %, 96 % and 95 % for breast ovarian and lung carcinomas, respectively. Conclusions The results demonstrated that the pool when used together with conventional methods, is useful in analysis of serous effusions in diagnostic investigations.

scholarly journals Polarity orientation and assembly process of microtubule bundles in nocodazole-treated, MAP2c-transfected COS cells.

1995 ◽  
Vol 6 (8) ◽  
pp. 981-996 ◽  
Author(s):  
R Takemura ◽  
S Okabe ◽  
T Umeyama ◽  
N Hirokawa
Keyword(s):  
Electron Microscope ◽  
Model System ◽  
Sf9 Cells ◽  
Assembly Process ◽  
Microtubule Associated Proteins ◽  
Cos Cells ◽  
Microtubule Polarity ◽  
Neuronal Processes ◽  
Associated Proteins ◽  
Peripheral Cytoplasm

Microtubule bundles reminiscent of those found in neuronal processes are formed in fibroblasts and Sf9 cells that are transfected with the microtubule-associated proteins tau, MAP2, or MAP2c. To analyze the assembly process of these bundles and its relation to the microtubule polarity, we depolymerized the bundles formed in MAP2c-transfected COS cells using nocodazole, and observed the process of assembly of microtubule bundles after removal of the drug in cells microinjected with rhodamine-labeled tubulin. Within minutes of its removal, numerous short microtubule fragments were observed throughout the cytoplasm. These short fragments were randomly oriented and were already bundled. Somewhat longer, but still short bundles, were then found in the peripheral cytoplasm. These bundles became the primordium of the larger bundles, and gradually grew in length and width. The polarity orientation of microtubules in the reformed bundle as determined by "hook" procedure using electron microscope was uniform with the plus end distal to the cell nucleus. The results suggest that some mechanism(s) exists to orient the polarity of microtubules, which are not in direct continuity with the centrosome, during the formation of large bundles. The observed process presents a useful model system for studying the organization of microtubules that are not directly associated with the centrosomes, such as those observed in axons.

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