Pressure and temperature effects on growth and viability of the hyperthermophilic archaeon Thermococcus peptonophilus
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© Springer-Verlag 1997
O R I G I N A L PA P E R
Francesco Canganella · Juan M. Gonzalez · Miki Yanagibayashi · Chiaki Kato · Koki Horikoshi
Pressure and temperature effects on growth and viability of the hyperthermophilic archaeon Thermococcus peptonophilus
Received: 21 October 1996 / Accepted: 5 February 1997
Abstract We studied the effects of high temperatures and elevated hydrostatic pressures on the physiological behavior and viability of the extremely thermophilic deep-sea archaeon Thermococcus peptonophilus. Maximal growth rates were observed at 30 and 45 MPa although no significant increases in cell yields were detected. Growth at 60 MPa was slower. The optimal growth temperature shifted from 85° C at 30 MPa to 90–95° C at 45 MPa. Cell viability during the stationary phase was also enhanced under high pressure. A trend towards barophily at pressures greater than those encountered in situ at the sea floor was demonstrated at increasing growth temperatures. The viability of cells during starvation, at high temperature (90, 95° C), and at low temperature (10° C) was enhanced at 30 and 45 MPa as compared to atmospheric pressure. These results show that the extremely thermophilic archaeon T. peptonophilus is a barophile. Key words Thermococcus peptonophilus · Extreme thermophiles · Large-scale cultivation · Hydrostatic pressure · Barophiles
Introduction Studies focusing on microbial life at high pressure have become feasible since deep-sea microbes have become available to investigators. The term “deep-sea” usually refers to waters deeper than 1,000 m which represent 75% F. Canganella1 · J. M. Gonzalez2 · M. Yanagibayashi · C. Kato (Y) · K. Horikoshi The Deepstar Group, Japan Marine Science and Technology Center, 2–15 Natsushima-cho, Yokosuka 237, Japan Permanent address: of Agrobiology and Agrochemistry, University of Tuscia, via C. de Lellis, I-01100 Viterbo, Italy Present address: 2 COMB, Columbus Center, 701 E. Pratt St., Baltimore, MD 21202, USA 1 Department
of the total volume of the oceans (Jannasch and Taylor 1984). The mean temperature at 3,800 m, the average depth of the oceans, is 2° C, but differences can be measured at the same depth in different locations around the world, and these differences are thought to be large enough to achieve niche separation (Yayanos 1986). This is certainly the case at hydrothermal vent sites, first discovered 17 years ago (Corliss et al. 1979), where warm and/or hot fluids are emitted. These sites have been found in several tectonically active areas of the ocean floor (Prieur et al. 1995), and hydrothermal springs usually have different physicochemical compositions. They are characterized by a low pH and high concentrations of dissolved gases and minerals as compared to the surrounding sea water (Jannasch and Wirsen 1985; Prieur 1992). Both shallow and deep hydrothermal vents are colonized by organisms capable of chemolithotrophic and chemoorganotrophic metabolism at temperatures above 100° C and pressures around 20–30 MPa (Stetter 1992; Belkin et al. 1986; Deming
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