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Biomedical subjects

G Vidali

Publications and source records attributed to G Vidali.

At least 91 records · Page 5Linked to original sources
PubMed1975

Selective synthesis and accumulation of nuclear non-histone proteins during carcinogenesis of the colon induced by 1, 2-dimethylhydrazine.

The complement of nuclear non-histone proteins in epithelial cells of the colon is progressively altered during the course of carcinogenesis induced by 1, 2-dimethylhydrazine, until finally the nuclear proteins of tumor cells are easily distinguishable from those of the surrounding normal tissue. These changes in nuclear protein compostion reflect earlier differences in the rates of synthesis of individual protein species. Radioisotopic double-labeling experiments show that the synthesis of nuclear proteins of molecular weights 44,000 and 62,000 is selectively accelerated within 4 weeks after administration of the carcinogen, long before any morphological indications of malignancy appear.

Amino Acids↗
PubMed1975

Selective effects of inhibitors of protein synthesis on metabolism of nuclear anc cytoplasmic proteins: evidence for coordinate synthesis of non-histone chromosomal proteins.

We have compared the effects of inhibitors of protein synthesis on the metabolism of nuclear and cytoplasmic proteins of HeLa S-3 cells. L-1-tosylamido-2-phenylethyl chloromethyl ketone, a potent inhibitor of polypeptide chain initiation, was shown to preferentially inhibit the synthesis of cytoplasmic proteins and of histones at concentrations that permit continued amino acid incorporation into nuclear non-histone proteins. Comparisons of the molecular weight distributions of newly synthesized proteins in the presence and absence of L-1-tosylamido-2-phenylethyl chloromethyl ketone have revealed striking differences between nuclear anc cytoplasmic protein fractions. Differential effects on the synthesis of cytoplasmic proteins, acid-soluble nuclear proteins, and residual nuclear proteins have also been obtained with the antibiotic, pactamycin, another inhibitor of polypeptide chain initiation. The incorporation of radioactive amino acids into nuclear non-histone proteins shows resistance to inhibition by pactamycin, but is strongly inhibited by agents such as puromycin and cycloheximide which block chain elongation. The possibility that proliferating cells have developed specialized mechanisms for the coordinate synthesis of chromosomal proteins, possibly involving polycistronic messenger RNAs, is tested and discussed.

Cell Nucleus↗
PubMed1975

Conformational studies on sequential polypeptides. Part V. Synthesis and characterization of (Pro-Leu-Gly)10, (Pro-LeuqGly)n and (Leu-Pro-Gly)n.

Syntheses of (Pro-Leu-Gly)n and (Leu-Pro-Gly)n, two synthetic polytripeptide analogues of the non-polar regions of collagen, via the corresponding tripeptide p-nitrophenyl-esters are described. The sequential polypeptide (Pro-Leu-Gly)10 was also obtained by solid-phase synthesis. In the following paper, conformational investigations on these polymers, both in solution and in solid state, will be described.

Amino Acid Sequence↗
PubMed1975

Fractionation of nuclei and analysis of nuclear proteins of rat liver and Morris hepatoma 7777.

The contributions of nuclear populations to the total profile of nuclear proteins in a tissue were examined in normal rat liver and Morris hepatoma 7777. Comparison by sodium dodecyl sulfate polyacrylamide gel electrophoresis of phenol-soluble nuclear proteins from tumor and control liver revealed additional proteins of molecular weight 60,000, 100,00, and 135,000 and the loss of proteins of about 45,000 and 55,000 in the tumor. Subfractionation of liver nuclei on a 30 to 50% sucrose gradient yielded three nuclear classes with nearly identical complements of the phenol-soluble proteins. Similar fractionation performed on the hepatoma nuclei also produced three nuclear populations. In the hepatoma nuclei, several differences in the phenol-soluble proteins were found between the minor, slowly sedimenting nuclear fraction, and the two major fractions, while the two latter fractions were very similar in their protein composition. Histones derived from both tissues were also compared electrophoretically, indicating a decrease in the concentration of histone H1(0)in all nuclear classes derived from the tumor.

Animals↗