[Biology of lysogenic strains of Streptococcus bovis and virulent mutants of their temperate phages].

Three lysogenic streptococcal strains and four virulent mutants of temperate phages were studied. The bacterial strains proved to be close to the type strain of Streptococcus bovis in their morphological, cultural, physiological, and biochemical properties. Investigation into the interaction of the lysogenic cultures with virulent mutants of temperate phages showed that the culture age optimal for infecting was 3-5 h; intense lysis began in the second hour after infection and was virtually completed by the end of the third hour, i.e., the procedure of obtaining phages in HMT medium took 7-8 h. Phage titers in phage lysates varied from 3.93 x 10(10) to 11.25 x 10(10) active phage particles per ml; residual amounts of viable bacteria varied from 0.7 x 10(6) to 34.0 x 10(6) cells per ml. In liquid HMT medium, phage production by lysogenic cultures was not limited by 0.3% glucose or maltose, 0.5% peptone, or casein hydrolysate. Descriptions of virulent mutants VM 6/6, VM 32/6, VM 28/28, and VM 54/54 of temperate phages of Str. bovis are presented.