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Z A Medvedev

Publications and source records attributed to Z A Medvedev.

34 records · Page 2Linked to original sources
PubMed1979

Age-related changes of the pattern of non-histone chromatin proteins from rat and mouse liver chromatin.

The non-histone chromatin (NHC) proteins which are loosely bound to DNA were extracted from young and old mouse and rat liver chromatin by 0.35 M NaCl and fractionated into three groups: water-soluble, 0.14 M NaCl soluble and 0.35 M NaCl soluble. NHC proteins in each fraction were separated by SDS-disc polyacrylamide gel electrophoresis. Special attempts were made to locate minor high-molecular-weight proteins which develop faint bands. It was found that the aging of liver cells is associated with increase in number and quantities of high-molecular-weight NHC proteins in the water-soluble group. Salt-soluble groups of NHC proteins show fewer changes of pattern.

Aging↗
PubMed1978

Tissue specificity and age changes for the pattern of the H1 group of histones in chromatin from mouse tissues.

Polyacrylamide gel electrophoresis of the H1 group of histones extracted from different rat and mouse tissues shows a different pattern of fraction (H1, H1 degrees, H1 degrees met) when the two species are compared. Different tissues of each species also have a different pattern of H1 histone fraction and subfraction. However, the age-associated changes of mouse H1 histones from liver and spleen chromatin show the same type of alteration of fraction ratios which had been demonstrated in our earlier research with rat tissues. In both species there is a relative increase of the F1 degree and F1 degree met fractions in tissues from old animals. The presence of the F1 degree fraction in only non-dividing cells suggests that there may be an age-specific type of chromatin condensation.

Aging↗
PubMed1977

Age changes of the pattern of F1 histone subfractions in rat liver and spleen chromatin.

The polyacrylamide gel electrophoresis of total histone extracted from young (3 months) and old (26-27 months) rat tissues does not show age-related differences in the pattern of the main five histones. However, when the lysine-rich F1 histone was extracted from chromatin separately by perchloric acid and purified by Biogel P-60 column chromatography from chromatin of rat liver and spleen, the polyacrylamide gel electrophoresis did show obvious age changes in the distribution of F1, F1o, and F1(00) subfractions. In liver chromatin the increase of rat-specific methionine-containing subfraction (F1met.) was also found.

Aging↗
PubMedDate not supplied

Identification of minor tightly bound H1 histone subfractions which fail to cleave their initiator methionine.

Groups of CBA mice were administered [35S] methionine (1 mCi/mouse). Non-histone proteins, H1 and H1(0) histones and nucleosomal core histones were isolated from different issues by selective extractions. The measurements of radioactivity of individual bands and autoradiography of dry gels were used to identify methionine-containing and methionine-free histone variants. H1A and H1B histone variants extracted with 5% perchloric acid were methionine-free. However, minor sub-fractions of these histones which are more tightly bound to DNA (and which can be extracted only with 0.25 N HCl) contained [35S] methionine and did show a higher specific activity than methionine-containing nucleosomal hitones. Cyanogen Bromide reaction which destroys non-histone proteins and methionine-containing nucleosomal histones removes radioactivity but does not alter the position of methionine-containing H1 minor bands. This indicates that the radioactive methionine occupies only the N-terminus of the H1 molecules. It is suggested that this methionine is an uncleaved initiator methionine. The presence of these methionine-containing minor H1 subfractions varies in different tissues.

Age Factors↗
PubMedDate not supplied

The past and the future of experimental gerontology.

This paper is based on a lecture on the history and the perspectives of experimental gerontology at the symposium in Nürnberg on the occasion of the 10th year jubilee of the Institute of Gerontology of the University of Erlangen. The discussion links the studies and ideas of the founders of gerontology as an interdisciplinary science (Metchnikoff, Korenchevsky, Bogomolets, Verzár) with some modern trends in experimental gerontology and ageing-related fields of biotechnology.

Biotechnology↗