To further understand the relationships between DNA dam age, DNA repair, and cellular end points such as survival and mutation, the repair capacity of a DNA repair-deficient mutant (strain UV-20) of Chinese hamster ovary cells was character ized in response to DNA cross-linking agents. This mutant, previously shown to be hypersensitive to killing by both ultra violet light and the cross-linking...

The regulation of the activity of transport System L for neutral amino acids has been investigated in Chinese hamster ovary cells. Incubation of the temperature-sensitive leucyl-tRNA synthetase mutant CHO-tsH1 at marginally permissive temperatures results in leucine-limited growth and increased transport of branched chain and aromatic amino acids. This temperature-dependent transport enhancemen...

A major problem in cancer therapy is tumor drug resistance such as is found with antifolates (e.g., methotrexate [MTX]). We are specifically interested in the role of the human folate receptor (hFR) in MTX resistance. To investigate whether transfection of hFR results in increased MTX uptake and increased drug sensitivity, human mammary carcinoma (MCF-7) cells and Chinese hamster ovary cells (C...

The bek gene encodes a member of the high-affinity fibroblast growth factor receptor family. The BEK/FGFR-2 receptor is a membrane-spanning tyrosine kinase with the typical features of FGF receptors. We have cloned a murine bek cDNA and expressed it in receptor-negative Chinese hamster ovary cells and in 32D myeloid cells. The BEK receptor expressed in Chinese hamster ovary cells binds acidic F...

A biochemical basis for the LEClO mutant phenotype of Chinese hamster ovary cells has been identified. Independent LEClO mutants, originally selected for resistance to the toxicity of ricin, have been shown to exhibit reduced binding of la61-ricin at the cell surface. Although this is indicative of structural changes in cellsurface carbohydrates, labeling of plasma membranes with galactose o~id...

A 48-h treatment with vinyl acetate (0.05-1 mM) induced a drastic increase in sister chromatid exchanges (SCEs) and (in first division cells) structural chromosome aberrations in cultured human lymphocytes. The effects were more pronounced in cultures of isolated lymphocytes than in whole-blood cultures. A distinct dose-dependent induction of SCEs similarly occurred in Chinese hamster ovary cel...

introduction: genital system is important herd in animal's creation. it is necessary for animal reproduction. mammal has two sex in genital system such as male and female in separated animals. animal reproduction destroyed by disorder of genital system. in this case, animals cannot produce an animal similar to them. finally it cause overthrow a species of animals. methods: histomorphologic...