Sara H. Goldemberg

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When putrescine is added to polyamine starved cultures of an E. coli strain difficient in the biosynthesis of putrescine, the protein synthesis is enhanced almost immediately and the ribosomal pattern changes concomitantly, increasing the ratio 70S monomer/ribosomal subparticles. Studies with cell-free systems derived from polyamine starved or unstarved(More)
Cells of Saccharomyces cerevisiae 179-5, an ornithine decarboxylase mutant (spe-1), showed several ultrastructural abnormalities when cultivated in the absence of polyamines. Besides the appearance of microvacuole-like spaces in the cytoplasm and of deformed nuclei, the most important alterations seemed to be located in the cell wall, which was thicker and(More)
A polyamine-auxotrophic mutant of E. coli was cultivated in the presence or absence of putrescine and submitted to heat shock over 3 different ranges of temperature. In all cases, protein synthetic capacity measured in comparison to that of cultures at the preshift temperature was much higher in polyamine-depleted bacteria under thermic stress. Addition of(More)
The polyamine content of the Escherichia coli polyamine-auxotrophic strain BGA 8 seemed to influence the effects of nalidixic acid, an antibiotic acting on subunit A of DNA gyrase. The growth rate was more affected under conditions of putrescine depletion and the inhibition could be partially relieved if the polycation was added back to the culture. DNA(More)