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Biomedical subjects

C Goodpasture

Publications and source records attributed to C Goodpasture.

5 recordsLinked to original sources

Establishment and characterization of a cell line from the American opossum (Didelphys virginiana).

A permanent tissue-cultured cell line (designated OK) has been established from kidney tissue of an adult American opossum. The OK line has been characterized with respect to morphology, chromosome constitution, tissue-culture requirements, and attainable mitotic arrest. The cells are epithelial-like with a stable nondiploid chromosomal modal number of 23. Cells grown in Eagle's minimal essential medium with 10% fetal bovine serum have a mean doubling time of 18 hr. The cell line OK is potentially useful for the isolation and purification of the mammalian X chromosome because of the size differential between the smaller X's and the larger autosomes.

Animals

An improved technique for selective silver staining of nucleolar organizer regions in human chromosomes.

A reliable technique for staining human chromosomal nucleolar organizers (NOR's) with silver solutions is described. The NOR's can be selectively stained dark brown by silver solutions leaving the chromosome arms unstained and available for counterstaining with orcein or Giemsa dyes. Unequivocal identification of chromosome pairs bearing NOR's can be achieved using fluorescent banding techniques followed by silver staining. The silver staining procedure for NOR's was simplified and standardized through control of the chemical and physical conditions during silver impregnation and developing.

Chromosomes

Human nucleolus organizers: the satellites or the stalks?

A silver-staining technique specific for demonstrating nucleolus organizer regions (NOR) showed that the achromatic stalks of the 10 acrocentric autosomes of the human complement represent the NORs. Some variability in number of stained stalks is observed from cell-to-cell and from individual-to-individual. The silver-stained masses may extend beyond the stalks and cover the satellites, especially in chromosomes with short stalks or minute satellites.

Cell Nucleolus

Visualization of nucleolar organizer regions im mammalian chromosomes using silver staining.

A simple ammoniacal silver staining procedure, designated Ag-AS, differentially stains the chromosomal locations of ribosomal DNA in certain mammalian species. This was critically demonstrated by Ag-AS staining of the nucleolus organizer regions in karyotypes of the same species and cell lines used for locating the ribosomal cistrons by DNA/RNA in situ hybridization. With Ag-AS, silver stained NORs (Ag-NORs) are visualized as black spherical bodies on yellow-brown chromosome arms. Ag-NORs were visualized throughout mitosis at the secondary constrictions in the rat kangaroo, Seba's fruit bat, Indian muntjac, and Rhesus monkey. The Chinese hamster and cattle have telomeric Ag-NORs, the mouse subcentromeric Ag-NORs, and the field vole Ag-NORs as minute short arms or choromosomal satellites. Ag-NORs occur at both secondary constrictions and at telomeres in the cotton rat. Variability in Ag-NOR pattern included differences in the number of Ag-NORs per cell within a cell population, size of Ag-NORs among chromosomes of a complement, and presence of Ag-NOR on particular chromosomes in two cell lines of the Chinese hamster. The available cytochemical data suggest that the Ag-AS reaction stains chromosomal proteins at the NOR rather than the rDNA itself.

Animals

A karyological study of nine species of Torymus (Hymenoptera: Torymidae).

Haploid karyotypes composed of 5 metacentrics (T. umbilicatus, T. koebelei), 4 metacentrics plus 2 telocentrics (T. tubicola), 5 metacentrics plus 1 telocentric (T. warreni), 5 metacentrics plus 1 acrocentric (T. baccharidis, T. vesiculi, T. occidentalis, T. capillaceus), and 6 metacentrics (T. californicus) are described. Five metacentrics are postulated as ancestral for the Torymidae, based on karyotype frequency for the family and Robertsonian relationships among taxa. Karyotypes of 5 metacentrics plus 1 telocentric are considered ancestral for the genus Torymus. Derived karyotypes have apparently evolved independently in several lineages within the genus.

Animals