title: The hyperthermophilic anaerobe Thermotoga Maritima is able to cope with limited amount of oxygen: insights into its defence strategies.
abstract: Thermotoga maritima, an anaerobic hyperthermophilic bacterium, was found able to grow in the presence of low concentrations of oxygen of up to 0.5% (v/v). Differential proteomics and transcripts analysis by qRT-PCR were used to identify the defence strategies used by T. maritima to protect itself against oxygen. A flavoprotein, homologous to rubredoxin oxygen oxidoreductase was found to be overproduced when cells were cultured in oxidative conditions. The recombinant protein, produced in Escherichia coli, exhibited an oxygen reductase activity, which could account for the observed decrease in oxygen concentration during growth. The gene encoding this oxygen reductase belongs to a multicistronic unit that includes genes encoding proteins involved in exopolysaccharide biosynthesis, which may be related to a biofilm formation induced by the presence of oxygen. Enzymes involved in reactive oxygen species detoxification, iron-sulfur centre synthesis/repair and the cysteine biosynthesis pathway were also overproduced. All these enzymatic systems together contribute to the defence strategy of T. maritima against oxygen. Because of the position of T. maritima in deep branches of the phylogenetic tree, we suggest that these strategies can be considered as ancestral mechanisms first developed by anaerobic microorganisms on the early Earth to protect themselves against primary abiotic or biotic oxygen production.
authors.affiliation: Unité Interactions et Modulateurs de Réponse, IBSM - CNRS, Marseille, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Le Fourn
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Fardeau
authors.forename: Bernard
authors.initials: B
authors.lastname: Ollivier
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lojou
authors.forename: Alain
authors.initials: A
authors.lastname: Dolla
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006358:Hot Temperature; D020411:Oligonucleotide Array Sequence Analysis; D010100:Oxygen / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D020124:Thermotoga maritima / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D017382:Reactive Oxygen Species; D010100:Oxygen