Inhibition of Phage Development in Bacillus cereus Strain T by Pre-spore Extracts of Bacilli

Abstract

THE susceptibility of infection of a bacillus by a bacteriophage varies with the physiological state of an organism. Goldberg and Gollakota¹ observed that a phage for Bacillus cereus strain T infected the organism in the vegetative stage and lysed the bacterium with the release of new phage particles. But when the phage was mixed with the pre-spores of the bacteria, the phage particles were able to adsorb to the micro-organisms but did not cause lysis of the culture. The bacilli progressed towards sporulation and produced spores as in an uninfected culture, but after germination the cells lysed. It was also shown that in these conditions the phage genome was incorporated into the spore. Investigations were carried out in order to understand the inhibition of phage multiplication during the pre-spore stage in sporulating bacilli. We report here evidence for the presence of a factor in pre-spore extracts of sporulating organisms able to suppress phage multiplication in a permissive system.