Lysin production by phi C2(W), a prolate phage for Streptococcus lactis C2

Area of Science:

• Microbiology
• Bacteriophage research
• Dairy starter cultures

Background:

• Bacteriophages can impact starter culture performance in dairy fermentation.
• Understanding phage-host interactions is crucial for controlling fermentation processes.

Purpose of the Study:

• To characterize bacteriophage phi C2(W) and its effect on Streptococcus lactis.
• To investigate the mechanism behind phage-induced inhibition of acid production.

Main Methods:

• Morphological characterization of bacteriophage phi C2(W).
• Infection assays with paired and multi-strain cultures of Streptococcus lactis.
• Analysis of phage lysates for lytic activity.

Main Results:

• Bacteriophage phi C2(W) has a prolate head and non-contractile tail.
• phi C2(W) significantly inhibited acid production in most tested Streptococcus lactis cultures.
• Phage lysates contained a phage-induced lysin responsible for lysis of non-homologous strains.

Conclusions:

• The inhibitory effect of phi C2(W) is mediated by a phage-induced lysin.
• This lysin allows phi C2(W) to indirectly control phage-insensitive strains in mixed cultures.
• Bacteriophage phi 712 does not produce a similar lysin.