STUDIES ON THE RELATION OF CULTURAL CONDITIONS AND VIRULENCE OF PASTEURELLA PESTIS

EFFECTS OF BICARBONATE ON GROWTH OF PASTEURELLA PESTIS II

“…The virulent cells in an inoculum of Pasteurella pestis will not grow, or at least they have a prolonged lag phase, when cultured aerobically at 37 C in a broth medium that supports the aerobic growth of virulent cells at 26 C (Fukui et al, 1957;Higuchi and Carlin, 1958;Surgalla, Andrews, and Baugh, 1964). The avirulent mutants invariably present in the inoculum initiate growth immediately at 37 C and soon predominate in the cultures grown at this temperature.…”

STUDIES ON THE NUTRITION AND PHYSIOLOGY OFPASTEURELLA PESTIS

“…The characteristic difference in the length of the lag phase between virulent and avirulent strains of P. pestis when grown in the modified synthetic medium at 37 C may indicate the existence of a specific nutritional requirement in virulent strains. Such a theory may provide an explanation for the rapid loss in virulence observed in P. pestis strains when cultured under certain conditions in vitro at 37 C (Fukui et al, 1957).…”

Effect of Ca 2+ on the Synthesis of Deoxyribonucleic Acid in Virulent and Avirulent Yersinia

“…7, are shown in Table 1. DISCUSSION Initially virulent cultures of yersiniae often become avirulent after aeration at 37 C because of the emergence of VWcells (6)(7)(8)18). This shift in population can be prevented by cultivation at high pH (18) or by addition of compounds such as NaHCO3, pyrimidines, 2,4-dinitrophenol, potassium iodide, salicylate ions, and biliverdin, which appear primarily to retard the growth of VWorganisms (1,6,21).…”