title: The Influence of the Toxin/Antitoxin mazEF on Growth and Survival of Listeria monocytogenes under Stress.
abstract: A major factor in the resilience ofListeria monocytogenesis the alternative sigma factor B (σB). Type II Toxin/Antitoxin (TA) systems are also known to have a role in the bacterial stress response upon activation via the ClpP or Lon proteases. Directly upstream of the σBoperon inL. monocytogenesis the TA systemmazEF, which can cleave mRNA at UACMU sites. In this study, we showed that themazEFTA locus does not affect the level of persister formation during treatment with antibiotics in lethal doses, but exerts different effects according to the sub-inhibitory stress added. Growth of a ΔmazEFmutant was enhanced relative to the wildtype in the presence of sub-inhibitory norfloxacin and at 42 °C, but was decreased when challenged with ampicillin and gentamicin. In contrast to studies inStaphylococcus aureus, we found that themazEFlocus did not affect transcription of genes within the σBoperon, but MazEF effected the expression of the σB-dependent genesopuCAandlmo0880, with a 0.22 and 0.05 fold change, respectively, compared to the wildtype under sub-inhibitory norfloxacin conditions. How exactly this system operates remains an open question, however, our data indicates it is not analogous to the system ofS. aureus, suggesting a novel mode of action for MazEF inL. monocytogenes.
authors.affiliation: Department of Biotechnology and Biomedicine, Technical University of Denmark, Matematiktorvet Bldg. 301, DK-2800 Kongens Lyngby, Denmark. thocu@bio.dtu.dk.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Curtis
authors.affiliation: Department of Biotechnology and Biomedicine, Technical University of Denmark, Matematiktorvet Bldg. 301, DK-2800 Kongens Lyngby, Denmark. takenoko.no.satousan@gmail.com.
authors.forename: Ippei
authors.initials: I
authors.lastname: Takeuchi
authors.affiliation: Department of Biotechnology and Biomedicine, Technical University of Denmark, Matematiktorvet Bldg. 301, DK-2800 Kongens Lyngby, Denmark. gram@bio.dtu.dk.
authors.forename: Lone
authors.initials: L
authors.lastname: Gram
authors.affiliation: Department of Biotechnology and Biomedicine, Technical University of Denmark, Matematiktorvet Bldg. 301, DK-2800 Kongens Lyngby, Denmark. gmkn@bio.dtu.dk.
authors.forename: Gitte M
authors.initials: GM
authors.lastname: Knudsen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D005798:Genes, Bacterial; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development*; D050296:Microbial Viability; D009876:Operon; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; C480945:SigB protein, Listeria monocytogenes; D012808:Sigma Factor
keywords: Listeria monocytogenes; MazEF; antibiotics; persister cells; sigma B (σB); stress response; sub-MIC; toxin-antitoxin modules