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S Zamenhof

Publications and source records attributed to S Zamenhof.

71 records · Page 4Linked to original sources
PubMed1968

DNA (cell number) and protein in neonatal brain: alteration by maternal dietary protein restriction.

Female rats were maintained on 8 or 27 percent protein diet by a pair-feeding schedule for 1 month before mating and throughout gestation. The brains of newborn rats from females on the 8 percent protein diet contained significantly less DNA and protein compared to the progeny of the females on the 27 percent diet. The data on DNA indicate that there are fewer cells; the protein content per cell was also lower. If, at birth, the brain cells are predominantly neurons, and their number becomes final at that time, then such dietary restriction may result in some permanent brain-neuron deficiency. This quantitative alteration in number as well as the qualitative one (protein per cell) may constitute a basis for the frequently reported impaired behavior of the offspring from protein-deprived mothers.

Animals↗
PubMed1965

Genetic Factors in Radiation Resistance of Bacillus subtilis.

Zamenhof, Stephen (University of California, Los Angeles), Hela Bursztyn, T. K. Ramachandra Reddy, and Patrice J. Zamenhof. Genetic factors in radiation resistance of Bacillus subtilis. J. Bacteriol. 90:108-115. 1965.-A study of several wild cross-transformable strains of Bacillus subtilis revealed differences in the resistance of their spores to X rays. Closer study of two such strains revealed differences of the same type when vegetative cells were exposed to X rays or to ultraviolet light (UV). Cell cultures repeatedly exposed to sublethal doses of UV (with cultivation between exposures) became more resistant to UV, presumably by enrichment in a more UV-resistant mutant. A sulfanilamide-resistant mutant of one strain (vegetative cells and spores) was less resistant to ionizing radiation; this sensitivity was transferable by transformation. No difference in radiation-induced mutability could be demonstrated in any of the strains studied. It is concluded that, at least in the cases studied, (i) the differences in radiation resistance of spores of different strains are not just a result of a superimposition of a common spore resistance mechanism(s) but rather are an amplification of genetically determined resistance differences in vegetative cells of these strains; (ii) sulfanilamide-resistance locus (p-aminobenzoic acid overproduction locus) is one of the loci of radiation sensitivity; (iii) no evidence was obtained that the differences in radiation resistance of cells or spores can be ascribed to differences in radiation resistance of their deoxyribonucleic acid.

Journal Article↗