title: Tungsten-enhanced growth of Methanosphaera stadtmanae.
abstract: BACKGROUND
  The methanogenic Archaea Methanosphaera stadtmanae has been detected in the human gut microbiota by both culture and culture-independent methods. Its growth reaches an exponential phase after 5 to 7-day culture in medium 322 (10% vol). Our recent successful isolation of Methanomassiliicoccus luminyensis, a tungstate-selenite-requiring Archaea sharing similar metabolism characteristics with M. stadtmanae prompted us to study the effects of tungsten and selenium on M. stadtmanae growth.
  
  
  RESULTS
  Addition of 0.2 mg/L sodium tungstate to medium 322 yielded, 48 hours after inoculation, a growth rate equivalent to that obtained after 6 days with control culture as measured by methane monitoring and optical density measurement. Addition of 50 μg/mL sodium selenate had no effect on M. stadtmanae growth. Quantitative real-time PCRs targeting the M. stadtmanae 16S rRNA confirmed these data.
  
  
  CONCLUSIONS
  These data provide new information regarding the poorly known nutritional requirements of the human gut colonizing organismsM. stadtmanae. Adding sodium tungstate to basal medium may facilitate phenotypic characterization of this organism and additionally aid the isolation of new Archaea from complex host microbiota.
authors.affiliation: Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes UMR CNRS 6236 IDR 198, IFR48, Institut Méditerranée Infection, Aix-Marseille-Université, Marseille, France.
authors.forename: Bédis
authors.initials: B
authors.lastname: Dridi
authors.forename: Saber
authors.initials: S
authors.lastname: Khelaifia
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Fardeau
authors.forename: Bernard
authors.initials: B
authors.lastname: Ollivier
authors.forename: Michel
authors.initials: M
authors.lastname: Drancourt
mesh_terms: D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D008697:Methane / Q000378:metabolism; D017013:Methanobacteriaceae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D019642:RNA, Archaeal / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D064586:Selenic Acid; D018036:Selenium Compounds / Q000494:pharmacology; D013997:Time Factors; D017973:Tungsten Compounds / Q000494:pharmacology*
chemical_list: D019642:RNA, Archaeal; D012336:RNA, Ribosomal, 16S; D018036:Selenium Compounds; D017973:Tungsten Compounds; C025399:sodium tungstate(VI); D064586:Selenic Acid; D008697:Methane