Oral Session

　

S3 Physiology and Metabolisms

　

January 20, Tuesday

　

Morning session (09:00〜11:50)

S3-01〜S3-08

Chairperson:

Prof. D. PRIEUR

Prof. T. KRULWICH

　

Afternoon session

Part 1 (13:15〜15:05)　　Part 2 (15:30〜17:45)

S3-O9〜S3-O14　　　　　　S3-O15〜S3-O21

Chairperson:　　　　　　　Chairperson:

Prof. A. A. YAYANOS　　　Prof. J. DE BONT

Prof. R. AONO　　　　　　Prof. B. WITHOLT

　

Physiological Responses to Stress Conditions and Barophilic Behaviors of Deep-sea Vent Thermococcales

　

Daniel PRIEUR^*a,b, Viggo Thor MARTEINSSON^a, Pascale MOULIN^a, Jean Louis BIRRIEN^a, Marc VERNET^a, Dominique MARIE^a, Agata GAMBACORTA^c, and Anna Louise REYSENBACH^a

　

^a Station Biologique, CNRS, UPR 9042, 29682 Roscoff Cedex, France

^b Universite de Bretagne Occidentale, 29285 Brest Cedex, France

^c Istituto per la chimica di Molecole di Interesso Biologico, CNR, 80072 Arco Felice, Napoli, Italy

^d Rutgers University, Institute for Marine and Coastal Sciences, Cook College, New Brunswick, NJ 08903, USA

　

Among the hyperthermophilic Prokaryotes isolated from deep-sea hydrothermal vents, Thermococcales are particularly well represented. Strain GE5 of Pyrococcus abyssi has been exposed to various stress conditions that may occur in vent environments. Incubation under in situ pressure increased the maximal and minimal growth temperatures by 4℃, and enhanced survival at lethal temperature (106- 112℃). Few changes were observed in the protein profiles, but in the membrane lipids. Oxgen appeared toxic at growth range temperature, but cells survived for several weeks at 4℃. The strain was not affected by starvation in a minimal medium for at least one month at 4℃ and only minimally affected at 95℃ for several days. Cells were more resistant to oxygen in starvation medium. An other set of experiments allowed to isolate after enrichment cultures under high temperature and pressure a novel Thermococcales species: Thermococcus barophilus that showed a strong barophilic behaviour. Particularly this species expressed a HSP-like protein when grown under atmospheric pressure. The signification of these data in terms of dispersion and habitat of hyperthermohiles will be discussed.

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