title: Carbon and arsenic metabolism in Thiomonas strains: differences revealed diverse adaptation processes.
abstract: BACKGROUND
  Thiomonas strains are ubiquitous in arsenic-contaminated environments. Differences between Thiomonas strains in the way they have adapted and respond to arsenic have never been studied in detail. For this purpose, five Thiomonas strains, that are interesting in terms of arsenic metabolism were selected: T. arsenivorans, Thiomonas spp. WJ68 and 3As are able to oxidise As(III), while Thiomonas sp. Ynys1 and T. perometabolis are not. Moreover, T. arsenivorans and 3As present interesting physiological traits, in particular that these strains are able to use As(III) as an electron donor.
  
  
  RESULTS
  The metabolism of carbon and arsenic was compared in the five Thiomonas strains belonging to two distinct phylogenetic groups. Greater physiological differences were found between these strains than might have been suggested by 16S rRNA/rpoA gene phylogeny, especially regarding arsenic metabolism. Physiologically, T. perometabolis and Ynys1 were unable to oxidise As(III) and were less arsenic-resistant than the other strains. Genetically, they appeared to lack the aox arsenic-oxidising genes and carried only a single ars arsenic resistance operon. Thiomonas arsenivorans belonged to a distinct phylogenetic group and increased its autotrophic metabolism when arsenic concentration increased. Differential proteomic analysis revealed that in T. arsenivorans, the rbc/cbb genes involved in the assimilation of inorganic carbon were induced in the presence of arsenic, whereas these genes were repressed in Thiomonas sp. 3As.
  
  
  CONCLUSIONS
  Taken together, these results show that these closely related bacteria differ substantially in their response to arsenic, amongst other factors, and suggest different relationships between carbon assimilation and arsenic metabolism.
authors: Génétique Moléculaire, Génomique et Microbiologie, UMR 7156 CNRS and Université de Strasbourg, Strasbourg, France. chris.bryan@gem.u-strasbg.fr
authors: Christopher G
authors: CG
authors: Bryan
authors: Marie
authors: M
authors: Marchal
authors: Fabienne
authors: F
authors: Battaglia-Brunet
authors: Valérie
authors: V
authors: Kugler
authors: Christelle
authors: C
authors: Lemaitre-Guillier
authors: Didier
authors: D
authors: Lièvremont
authors: Philippe N
authors: PN
authors: Bertin
authors: Florence
authors: F
authors: Arsène-Ploetze
mesh_terms: D000222:Adaptation, Physiological; D001151:Arsenic / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism; D020562:Betaproteobacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D002244:Carbon / Q000378:metabolism*; D052837:Chemoautotrophic Growth / Q000187:drug effects; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D018053:Arsenites; D002244:Carbon; C015001:arsenite; D001151:Arsenic