Dataset Information

Abortive infection mechanisms and prophage sequences significantly influence the genetic makeup of emerging lytic lactococcal phages.

ABSTRACT: In this study, we demonstrated the remarkable genome plasticity of lytic lactococcal phages that allows them to rapidly adapt to the dynamic dairy environment. The lytic double-stranded DNA phage ul36 was used to sequentially infect a wild-type strain of Lactococcus lactis and two isogenic derivatives with genes encoding two phage resistance mechanisms, AbiK and AbiT. Four phage mutants resistant to one or both Abi mechanisms were isolated. Comparative analysis of their complete genomes, as well as morphological observations, revealed that phage ul36 extensively evolved by large-scale homologous and nonhomologous recombination events with the inducible prophage present in the host strain. One phage mutant exchanged as much as 79% of its genome compared to the core genome of ul36. Thus, natural phage defense mechanisms and prophage elements found in bacterial chromosomes contribute significantly to the evolution of the lytic phage population.

SUBMITTER: Labrie SJ

PROVIDER: S-EPMC1797345 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Abortive infection mechanisms and prophage sequences significantly influence the genetic makeup of emerging lytic lactococcal phages.

Labrie Simon J SJ Moineau Sylvain S

Journal of bacteriology 20061013 4

In this study, we demonstrated the remarkable genome plasticity of lytic lactococcal phages that allows them to rapidly adapt to the dynamic dairy environment. The lytic double-stranded DNA phage ul36 was used to sequentially infect a wild-type strain of Lactococcus lactis and two isogenic derivatives with genes encoding two phage resistance mechanisms, AbiK and AbiT. Four phage mutants resistant to one or both Abi mechanisms were isolated. Comparative analysis of their complete genomes, as well ...[more]

PMID: 17041060

Similar Datasets

Project description:The lytic cassette of Lactococcus lactis prophage TP712 contains a putative membrane protein of unknown function (Orf54), a holin (Orf55), and a modular endolysin with a N-terminal glycoside hydrolase (GH_25) catalytic domain and two C-terminal LysM domains (Orf56, LysTP712). In this work, we aimed to study the mode of action of the endolysin LysTP712. Inducible expression of the holin-endolysin genes seriously impaired growth. The growth of lactococcal cells overproducing the endolysin LysTP712 alone was only inhibited upon the dissipation of the proton motive force by the pore-forming bacteriocin nisin. Processing of a 26-residues signal peptide is required for LysTP712 activation, since a truncated version without the signal peptide did not impair growth after membrane depolarization. Moreover, only the mature enzyme displayed lytic activity in zymograms, while no lytic bands were observed after treatment with the Sec inhibitor sodium azide. LysTP712 might belong to the growing family of multimeric endolysins. A C-terminal fragment was detected during the purification of LysTP712. It is likely to be synthesized from an alternative internal translational start site located upstream of the cell wall binding domain in the lysin gene. Fractions containing this fragment exhibited enhanced activity against lactococcal cells. However, under our experimental conditions, improved in vitro inhibitory activity of the enzyme was not observed upon the supplementation of additional cell wall binding domains in. Finally, our data pointed out that changes in the lactococcal cell wall, such as the degree of peptidoglycan O-acetylation, might hinder the activity of LysTP712. LysTP712 is the first secretory endolysin from a lactococcal phage described so far. The results also revealed how the activity of LysTP712 might be counteracted by modifications of the bacterial peptidoglycan, providing guidelines to exploit the biotechnological potential of phage endolysins within industrially relevant lactococci and, by extension, other bacteria.

Dataset Information

Abortive infection mechanisms and prophage sequences significantly influence the genetic makeup of emerging lytic lactococcal phages.

Publications

Abortive infection mechanisms and prophage sequences significantly influence the genetic makeup of emerging lytic lactococcal phages.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets