title: High hydrostatic pressure increases amino acid requirements in the piezo-hyperthermophilic archaeon Thermococcus barophilus.
abstract: We have established a defined growth medium for the piezophilic hyperthermophilic archaeon Thermococcus barophilus, which allows growth yields of ca. 10(8) cells/ml under both atmospheric and high hydrostatic pressure. Our results demonstrate a major impact of hydrostatic pressure on amino acid metabolism, with increases from 3 amino acids required at atmospheric pressure to 17 at 40 MPa. We observe in T. barophilus and other Thermococcales a similar discrepancy between the presence/absence of amino acid synthesis pathways and amino acid requirements, which supports the existence of alternate, but yet unknown, amino acid synthesis pathways, and may explain the low number of essential amino acids observed in T. barophilus and other Thermococcales. T. barophilus displays a strong metabolic preference for organic polymers such as polypeptides and chitin, which may constitute a more readily available resource of carbon and energy in situ in deep-sea hydrothermal vents. We hypothesize that the low energy yields of fermentation of organic polymers, together with energetic constraints imposed by high hydrostatic pressure, may render de novo synthesis of amino acids ecologically unfavorable. Induction of this metabolic switch to amino acid recycling can explain the requirement for non-essential amino acids by Thermococcales for efficient growth in defined medium.
authors.affiliation: Laboratoire de Géologie de Lyon, UMR 5276 CNRS, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon, Lyon, France.
authors.forename: Anaïs
authors.initials: A
authors.lastname: Cario
authors.affiliation: Département Biosciences, Ecole Normale Supérieure de Lyon, Lyon, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Lormières
authors.affiliation: State Key Laboratory of Microbial Metabolism and State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xiang
authors.affiliation: Laboratoire de Géologie de Lyon, UMR 5276 CNRS, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon, Lyon, France. Electronic address: poger@ens-lyon.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Oger
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D001267:Atlantic Ocean; D002244:Carbon / Q000378:metabolism; D003470:Culture Media; D006874:Hydrostatic Pressure; D060086:Hydrothermal Vents / Q000382:microbiology; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*; D013312:Stress, Physiological; D019712:Thermococcus / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D003470:Culture Media; D002244:Carbon
keywords: Amino acids metabolism; Archaea; Deep biosphere; Piezophily; Thermococcales