Contribution of the CesR-regulated genes llmg0169 and llmg2164-2163 to Lactococcus lactis fitness

Roces, Clara; Campelo, Ana B.; Veiga, Patrick; Pinto, Joao P. C.; Rodrı́guez, Ana; Martı́nez, Beatriz

doi:10.1016/j.ijfoodmicro.2009.06.002

Cited by 15 publications

(13 citation statements)

References 31 publications

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“…lactis encode putative membrane-or stress-related proteins (441). One of the most upregulated genes is llmg_0169, encoding a small putative membrane protein of unknown function but with an essential role in protecting the cell against high temperatures (443). Among the most upregulated genes was the llmg_2163-llmg_2164 operon, which encodes a protein of unknown function and a putative transcriptional regulator.…”

Section: Mechanosensitive Channelsmentioning

confidence: 99%

“…The cooverexpression of these genes increased the resistance of Lc. lactis against Lcn972, while a mutant lacking llmg_2164 suffered from a low resistance to high temperature and salinity (443). The llmg_1155/spxB gene encodes a regulator that stimulates the expression of oatA, a gene coding for a protein involved in the O-acetylation of PG and conferring a high resistance of the cells to autolysis and lysozyme treatment (444).…”

Section: Mechanosensitive Channelsmentioning

confidence: 99%

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Stress Physiology of Lactic Acid Bacteria

Papadimitriou

Alegría

Bron

et al. 2016

Microbiol Mol Biol Rev

508

404

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SUMMARYLactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g.,Lactococcus lactis), probiotic (e.g., severalLactobacillusspp.), and pathogenic (e.g.,EnterococcusandStreptococcusspp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.

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Section: Mechanosensitive Channelsmentioning

confidence: 99%

Section: Mechanosensitive Channelsmentioning

confidence: 99%

Stress Physiology of Lactic Acid Bacteria

Papadimitriou

Alegría

Bron

et al. 2016

Microbiol Mol Biol Rev

508

404

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“…In L. lactis, the response to cell envelope stress is governed by the two-component system CesSR, which has been shown to be triggered by lysozyme, nisin, and Lcn972 (26,39) and by heterologous protein secretion and phage infection (11,33). Although the CesR regulon is not fully understood, certain CesR-regulated components are known to contribute positively to L. lactis survival under technological relevant stresses (34).…”

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confidence: 99%

Isolation of Lactococcus lactis Mutants Simultaneously Resistant to the Cell Wall-Active Bacteriocin Lcn972, Lysozyme, Nisin, and Bacteriophage c2

Roces

Courtin

Kulakauskas

et al. 2012

Appl Environ Microbiol

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ABSTRACTLactococcin 972 (Lcn972) is a nonlantibiotic bacteriocin that inhibits cell wall biosynthesis by binding to lipid II. In this work, two mutants resistant to Lcn972,Lactococcus lactisD1 and D1-20, with high (>320 arbitrary units [AU]/ml) and low (80 AU/ml) susceptibilities, respectively, have been isolated. Resistance to Lcn972 did not impose a burden to growth under laboratory conditions, nor did it substantially alter the physicochemical properties of the cell surface. However, the peptidoglycan of the mutants featured a higher content of muropeptides with tripeptide side chains than the wild-type strain, linking for the first time peptidoglycan remodelling to bacteriocin resistance. Moreover,L. lactislacking a functionald,d-carboxypeptidase DacA (i.e., with a high content of pentapeptide side chain muropeptides) was shown to be more susceptible to Lcn972. Cross-resistance to lysozyme and nisin and enhanced susceptibility to penicillin G and bacitracin was also observed. Intriguingly, the Lcn972-resistant mutants were not infected by the lytic phage c2 and less efficiently infected by phage sk1. Lack of c2 infectivity was linked to a 22.6-kbp chromosomal deletion encompassing the phage receptor protein genepip. The deletion also included maltose metabolic genes and the two-component system (TCS) F. However, a clear correlation between these genes and resistance to Lcn972 could not be clearly established, pointing to the presence of as-yet-unidentified mutations that account for Lcn972 resistance.

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“…cDNA concentrations were correlated to quantify relative gene expression levels. The housekeeping gene tuf, encoding the elongation factor Tu, was used to normalize (43).…”

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confidence: 99%

The Lcn972 Bacteriocin-Encoding Plasmid pBL1 Impairs Cellobiose Metabolism in Lactococcus lactis

Campelo

Gaspar

Roces

et al. 2011

Appl Environ Microbiol

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pBL1 is a Lactococcus lactis theta-replicating 10.9-kbp plasmid that encodes the synthetic machinery of the bacteriocin Lcn972. In this work, the transcriptomes of exponentially growing L. lactis strains with and without pBL1 were compared. A discrete response was observed, with a total of 10 genes showing significantly changed expression. Upregulation of the lactococcal oligopeptide uptake (opp) system was observed, which was likely linked to a higher nitrogen demand required for Lcn972 biosynthesis. Strikingly, celB, coding for the membrane porter IIC of the cellobiose phosphoenolpyruvate-dependent phosphotransferase system (PTS), and the upstream gene llmg0186 were downregulated. Growth profiles for L. lactis strains MG1363, MG1363/pBL1, and MG1363 ⌬celB grown in chemically defined medium (CDM) containing cellobiose confirmed slower growth of MG1363/pBL1 and MG1363 ⌬celB, while no differences were observed with growth on glucose. The presence of pBL1 shifted the fermentation products toward a mixed acid profile and promoted substantial changes in intracellular pool sizes for glycolytic intermediates in cells growing on cellobiose as determined by highpressure liquid chromatography (HPLC) and nuclear magnetic resonance (NMR). Overall, these data support the genetic evidence of a constriction in cellobiose uptake. Notably, several cell wall precursors accumulated, while other UDP-activated sugar pools were lower, which could reflect rerouting of precursors toward the production of structural or storage polysaccharides. Moreover, cells growing slowly on cellobiose and those lacking celB were more tolerant to Lcn972 than cellobiose-adapted cells. Thus, downregulation of celB could help to build up a response against the antimicrobial activity of Lcn972, enhancing self-immunity of the producer cells.

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Contribution of the CesR-regulated genes llmg0169 and llmg2164-2163 to Lactococcus lactis fitness

Cited by 15 publications

References 31 publications

Stress Physiology of Lactic Acid Bacteria

Stress Physiology of Lactic Acid Bacteria

Isolation of Lactococcus lactis Mutants Simultaneously Resistant to the Cell Wall-Active Bacteriocin Lcn972, Lysozyme, Nisin, and Bacteriophage c2

The Lcn972 Bacteriocin-Encoding Plasmid pBL1 Impairs Cellobiose Metabolism in Lactococcus lactis

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