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Biomedical subjects

K S McCarty

Publications and source records attributed to K S McCarty.

At least 145 records · Page 8Linked to original sources

Evidence for a proposed initiation complex for protein synthesis in reticulocyte polyribosome profiles.

Polysomes consisting of 40S ribosomal subunits attached to monosomes, disomes, trisomes, and tetrasomes have been isolated for the first time by the use of isokinetic sucrose density gradients. They are formed upon incubation of rabbit reticulocyte lysate in the presence of 10 mM NaF. It is proposed that these structures represent transient initiation complexes for protein synthesis.

Animals↗

Actinomycin D: inhibition of respiration and glycolysis.

Actinomycin D inhibited respiration and anaerobic glycolysis of human leukemic leukocytes and lowered the adenosine triphosphate content of the cells. Inhibitory effects on respiration and on RNA synthesis could not be dissociated from one another over a wide range of drug concentrations. Actinomycin D also impaired protein synthesis, probably by decreasing the availability of adenosine triphosphate and by inhibiting messenger RNA.

Adenosine Triphosphate↗

Reduced Cd2+ accumulation and elevated metallothionein levels in a Cd2+ and Zn2+-resistant clonal CHO-K1 cell line.

A clonal cell line, R40F, was selected from a heterogenous population of Cd2+ and Zn2+-resistant CHO-K1 cells. These R40F cells demonstrated resistance to 120- and 4-fold higher concentrations of Cd2+ and Zn2+, respectively, than did wild type CHO-K1 cells. When cultured in the presence of low concentrations of Cd2+ (0.5-1.0 microM), the accumulation of intracellular Cd2+ in R40F cells appears to be significantly less than in wild type cells. Since R40F cells maintained in medium containing high concentrations of Cd2+ (200 microM) retain levels of Cd2+ equivalent to the intracellular concentration observed in wild type cells exhibiting cytotoxicity, it is assumed that reduced Cd2+ transport alone is unlikely to account for the resistance to Cd2+ toxicity. Exposure of R40F cells to non-toxic (2 microM or 100 microM) or toxic (200 microM) Zn2+ levels resulted in an accumulation of Zn2+ equal to, or greater than, that observed in the wild type cell. When compared to the basal level in uninduced wild type cells, metallothionein levels were elevated 14- and 23-fold, respectively, in R40F cells cultured in the presence of 0.5 microM Cd2+ and 100 microM Zn2+. These results are consistent with the hypothesis that R40F cells express Cd2+ and Zn2+ resistance as a consequence of a reduction in unbound intracellular Cd2+ levels and an elevation of metallothionein synthesis.

Animals↗