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A five‐gene stress survival islet (SSI‐1) that contributes to the growth of Listeria monocytogenes in suboptimal conditions
Author(s) -
Ryan S.,
Begley M.,
Hill C.,
Gahan C.G.M.
Publication year - 2010
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2010.04726.x
Subject(s) - listeria monocytogenes , islet , biology , sigma factor , gene , mutant , gene expression , microbiology and biotechnology , strain (injury) , genetics , bacteria , promoter , insulin , anatomy
Aims: The aim of this study was to examine the contribution of a five‐gene islet ( lmo0444 – lmo0448 ) to the growth of Listeria monocytogenes under suboptimal conditions. Methods and Results: Bioinformatics and PCR analyses revealed that a five‐gene islet is present in c. half of all L. monocytogenes strains examined (66 in total). A deletion mutant that lacks the entire c. 8·7‐kb islet was created in L. monocytogenes strain LO28. This mutant was impaired in growth at low pH and at high salt concentrations and demonstrated a decreased ability to survive and grow in a model food system (frankfurters). Transcriptional analysis revealed that the islet is self‐regulated in that the product of lmo0445 regulates the expression of the other four genes. A role of the alternative stress sigma factor SigB in regulating the islet was also uncovered. Conclusions: The five‐gene islet (herein designated as SSI‐1; stress survival islet 1) contributes to the growth of L. monocytogenes under suboptimal conditions. Significance and Impact of the Study: SSI‐1 may contribute to the survival of certain strains of L. monocytogenes in food environments.