Lysogeny in Lactobacillus delbrueckii strains and characterization of two new temperate prolate-headed bacteriophages

摘要

Frequency of lysogeny in Lactobacillus delbrueckii strains (from commercial and natural starters) and preliminary characterization of temperate bacteriophages isolated from them. Induction of strains (a total of 16) was made using mitomycin C (MC) (0p"5 og mlp#). For 37% of the MC-treated supernatants, it was possible to detect phage particles or presence of killing activity, but only two active bacteriophages were isolated. The two temperate phages isolated were prolate-headed phages which belonged to group c of Lact. delbrueckii bacteriophages classification. Different DNA restriction patterns were obtained for each phage, while the structural protein profiles and packaging sites were identical. Distinctive one-step growth curves were exhibited by each phage. An influence of calcium ions was observed for their lysis in broth but not on the adsorption levels. Our study showed that lysogeny is also present in Lact. delbrueckii strains, including commercial strains. Commercial strains could be lysogenic and this fact has a great practical importance since they could contribute to the dissemination of active-phage particles in industrial environments.