title: Legionella pneumophila transcriptional response to chlorine treatment.
abstract: Legionella pneumophila is a ubiquitous environmental microorganism found in freshwater that can cause an acute form of pneumonia known as Legionnaires' disease. Despite widespread use of chlorine to ensure drinking water quality and awareness that L. pneumophila may escape these treatments, little is known about its effects on L. pneumophila. The aim of this study was to investigate the L. pneumophila transcriptional response induced by chlorine treatment. Transcriptome analysis, using DNA arrays, showed that a sublethal dose of chlorine induces a differential expression of 391 genes involved in stress response, virulence, general metabolism, information pathways and transport. Many of the stress response genes were significantly upregulated, whereas a significant number of virulence genes were repressed. In particular, exposure of L. pneumophila to chlorine induced the expression of cellular antioxidant proteins, stress proteins and transcriptional regulators. In addition, glutathione S-transferase specific activity was enhanced following chlorine treatment. Our results clearly indicate that chlorine induces expression of proteins involved in cellular defence mechanisms against oxidative stress that might be involved in adaptation or resistance to chlorine treatment.
authors.affiliation: Laboratoire de Chimie et Microbiologie de l'Eau, UMR 6008, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France. charles.bodet@univ-poitiers.fr
authors.forename: Charles
authors.initials: C
authors.lastname: Bodet
authors.forename: Tobias
authors.initials: T
authors.lastname: Sahr
authors.forename: Mathieu
authors.initials: M
authors.lastname: Dupuy
authors.forename: Carmen
authors.initials: C
authors.lastname: Buchrieser
authors.forename: Yann
authors.initials: Y
authors.lastname: Héchard
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002713:Chlorine / Q000494:pharmacology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D005798:Genes, Bacterial / Q000235:genetics; D016952:Legionella pneumophila / Q000187:drug effects* / Q000235:genetics* / Q000472:pathogenicity; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects*; D014774:Virulence / Q000187:drug effects / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D002713:Chlorine