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Biomedical subjects

M Rothstein

Publications and source records attributed to M Rothstein.

69 records · Page 4Linked to original sources
PubMed1970

Heme requirement for reproduction of a free-living nematode.

The free-living hermaphroditic nematode Caernorhabditis briggsae has a nutritional requirement for heme. The organism can be subcultured repeatedly in a chemically defined axenic medium that contains autoclaved bacterial cells (Escherichia coli) and sterols if a hemeprotein-containing fraction from liver is present. Pure myoglobin, hemoglobin, cytochrome c, and hemin, respectively, can substitute effectively for the liver fraction.

Animals↗
PubMed1968

Sterol requirement for reproduction of a free-living nematode.

The free-living, hermaphroditic nematode Caenorhabditis briggsae has a nutritional requirement for sterols. It will reproduce indefinitely in a liquid medium containing only bacterial cells (Escherichia coli) and salts if various sterols are present. Several other lipid-soluble materials are ineffective in supporting reproduction.

Animals↗
PubMedDate not supplied

Aging and the alteration of enzymes: a review.

The present status of research on age-related alterations of enzymes is reviewed. Evidence which makes it clear that "altered" enzymes do, in fact, exist in old animals is presented. The alteration may result from either a sequence change or a post-synthetic modification. The "error hypothesis" would support the former mechanism; a proposal based upon increasing half-lives of proteins with age could explain the latter. Evidence supporting or contradicting these alternatives is discussed.

Aging↗
PubMedDate not supplied

Recent developments in the age-related alteration of enzymes: a review.

Recent developments dealing with the age-related alteration of enzymes have been examined. Since the last review of this field, three enzymes have been purified to homogeneity from young and old nematodes (enolase, phosphoglycerate kinase, triosephosphate isomerase) and one from the liver of young and old rats (superoxide dismutase). In all cases except for triosephosphate isomerase, the enzymes from old animals show a reduced catalytic ability compared to those from young animals. In addition, new reports of increases in the amount of altered enzymes in late-passage cells in tissue culture have appeared, though contrary evidence has also been published. The data from these and other papers are compared and discussed. Possible explanations for the alteration of enzymes include error theory, substitution of individual amino acids and conformational change without sequence change. Though final conclusions cannot be made, the evidence favors the latter idea to explain the presence of altered enzymes in old animals.

Aging↗