Mechanism of in vitro inactivation of Lactobacillus phage PL-1 by D-glucosamine.

Abstract

d-Glucosamine selectively inactivated free PL-1 phage under the conditions in which the growth of host cells, Lactobacillus casei ATCC 27092, was not affected. Both the N-acetylated and non-aminated forms little affected the phage infectivity. The rate of phage inactivation by D-glu-cosamine was proportional to the time and temperature of the incubation, and about 0.1 m d-glucosamine showed the maximum inactivation effect. The phage inactivation was stimulated by Cu2 +, and inhibited by catalase and several oxygen radical scavengers. The inactivated phage was identical with the intact one with respect to the electron microscopic appearance, the density and the ability of combining with host cells. The DNA in the virion was fragmented by D-glucosamine and the DNA fragmentation was also stimulated by Cu2 +. With plasmid pBR322, d-glucosamine caused single-strand scission of ccc-DNA to give oc- and in succession linear-DNA. The inactivation of PL-1 phage by d-glucosamine was considered to be due to single-st...