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Biomedical subjects

M Bouteille

Publications and source records attributed to M Bouteille.

At least 55 records · Page 3Linked to original sources
PubMed1983

Visualization of a repeating subunit organization in rat hepatocyte chromatin fixed in situ.

The chromatin structure of rat hepatocytes fixed in situ was investigated in thin sections selectively stained for DNA with the Feulgen-like osmium-ammine reaction. Visualization of the chromatin structure was facilitated by the dispersal that occurred in the chromatin of regenerating rat hepatocytes at 24 h after partial hepatectomy. Our results show that repeating subunits were present both in the clumps and in the extended fibres of chromatin. These subunit particles appeared to be composed of an electron-translucent core delimited by a strongly electron-opaque DNA ring. Depending on the section plane, they displayed a morphology varying from a flat, oval shape to a rough circle. The mean diameter of the repeating subunits was 11 +/- 0.8 nm (S.D.) with a range from 9.5 to 13 nm. The thickness of the DNA ring was about 3 nm. Regarding the association of the subunits in the chromatin fibres, two types of fibres were visualized, 11 nm and 20-25 nm thick, respectively. The thinner fibres were composed of a linear array of adjoining subunits. In the thicker fibres the subunit organization did not clearly form discrete superunit structures.

Animals↗
PubMed1983

Evidence showing that the nucleolus-envelope region is located on the nor-bearing chromosomes in Aotus trivirgatus.

We investigated whether the existence of the Nucleolus-Envelope Region observed in dividing animal cells is related to the Nucleolus Organizer Region or to other chromosome segments of the NOR-bearing chromosomes, since NORs are usually adjacent to the chromosome segments attached to the nuclear envelope such as the centromere, telomere or heterochromatin region. We used Aotus Trivirgatus fibroblasts whose karyotype is characterized by a single pair of NORs located on the long arm of the third pair of chromosomes, far from the centromere, the telomere and any obvious heterochromatin region. All the nucleoli were seen to be clearly associated with the nuclear envelope but separated from it by the outermost layer of chromatin. These results further support the hypothesis that the NOR is a site of attachment of the chromatin to the nuclear envelope by means of the Nucleolus-Envelope Region. They show that genetically active chromatin is also attached to the nuclear envelope. A model of the arrangement of chromatin during interphase is proposed which provides a functional interpretation of the currently available data.

Animals↗
PubMed1982

Visualization of Ag-NOR proteins on nucleolar transcriptional units in molecular spreads.

Application of NOR silver staining to Pleurodeles oocyte nuclei showed selective silver deposits on the fibrillar part of the nucleoli in situ. This staining was adapted to nucleoli spread on grids, by a procedure which allowed the spreading of transcription units from both nucleoli and lampbrush chromosomes on the same grids. This permitted localization of the predominant nucleolar Ag-stained proteins on the nucleolar transcriptional units and not on the lampbrush chromosomes. These proteins were found exclusively on the transcribed part of the nucleolar genes and were not seen in apparently untranscribed spacer regions. The proteins seemed preferentially located on the DNP axis rather than on the RNP fibrils.

Animals↗
PubMed1982

The morphological relationship in electron microscopy between NOR-silver proteins and intranucleolar chromatin.

The relative distribution of NOR proteins and chromatin fibers in the nucleoli was visualized in human cell line. The chromatin was revealed by a Feulgen-like procedure using osmium-ammine as DNA tracer. This selective staining was combined with NOR-silver staining. We provide morphological evidence for constant overlapping of the silver deposit sites with dispersed intranucleolar chromatin fibers. Silver stained proteins were sometimes observed in contact with the chromatin fibers, suggesting that at least some of the Ag-NOR proteins might be closely connected with the dispersed nucleolar DNA.

Cell Line↗
PubMed1982

Localization by autoradiography of viral proteins in the parenchymal cells of the liver during frog virus 3 induced hepatitis of mice.

Frog virus 3 inoculated into mice induces an acute degenerative hepatitis. This hepatitis is of toxic origin since the virus is unable to multiply at 37 degrees C. The Kupffer cells, which are the target cells for FV3, reveal the presence of viral particles, viral DNA and proteins. Although the hepatocytes present early and drastic nuclear lesions, viral particles were never observed in these cells. Viral proteins however but not DNA, could be found inside parenchymal cells.

Animals↗
PubMed1981

Analysis of the spatial organization of the cell: a statistical method for revealing the non-random location of an organelle.

A method is proposed for testing the randomness of the location of an organelle within a given area of a cell section. The approach chosen is to analyse the distance between this organelle and a specific point considered as a point of reference. The method consists of converting this distance into the ratio of one given area to another and comparing the statistical distribution of the converted values to the uniform distribution. This method has the advantage of being valid in the absence of any restrictive assumptions concerning the heterogeneity in size and/or shape of the collection of sections sampled. Detailed examples are given to illustrate the practical use of the method, and its possible extensions are discussed.

Cell Nucleolus↗
PubMed1980

Ultrastructural localization of Ag-NOR stained proteins in the nucleolus during the cell cycle and in other nucleolar structures.

EM investigation of Ag-AS-NOR staining after short glutaraldehyde prefixation followed by Carnoy fixation maintained good ultrastructural preservation and reactive selectivity. This enables exact localization of silver deposits both in the fibrillar centers of typical or segregated nucleoli during interphase, and in chromosome NORs during mitosis. These results argue in favour of the possibility that fibrillar centers are the interphasic counterpart of chromosome NORs. Special structures such as nucleolar blobs and remnants usually considered to be of nucleolar origin, were also stained. - These findings seem to indicate a relationship between the distribution of the silver-stained proteins, the arrangement of the nucleolar structures and the degree of nucleolar activity resulting from the experimental conditions. These results are of interest at the time when the concept of the nucleolar matrix is gradually emerging.

Animals↗