Effect of ca on the synthesis of deoxyribonucleic Acid in virulent and avirulent yersinia.
Virulent and potentially virulent cells of Yersinia (Pasteurella) pestis produce virulence or V and W antigens (VW(+)) but remain static at 37 C during aeration in enriched Ca(2+)-deficient media containing 0.02 m Mg(2+). In this environment, which simulates mammalian intracellular fluid, VW(+) cells possessed a functional cytoplasmic membrane as judged by concentration of (14)C-isoleucine, release of (32)P, and consumption of oxygen at rates comparable to those of dividing cells cultivated with Ca(2+). Furthermore, rates of protein and ribonucleic acid synthesis were essentially identical in dividing and static VW(+) cells and in mutant VW(-) organisms. However, the rate of deoxyribonucleic acid (DNA) synthesis in static cells was about 10% of that observed in dividing organisms. Accordingly, bacteriostasis of VW(+) cells in the simulated intracellular environment is evidently caused by reactions directly associated with cessation of DNA synthesis rather than by alterations in the regulatory capacity of the cytoplasmic membrane.
Yang
G C
GC
Department of Microbiology and Public Health, Michigan State University, East Lansing, Michigan 48823.
Brubaker
R R
RR