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1 J. M. Wiame Research Institute for Microbiology, Free University of Brussels (VUB), and Flanders Inter-University Institute for Biotechnology, 1 ave E. Gryson, B-1070 Brussels, Belgium
2 The DEEP STAR Group, Japan Marine Science and Technology Center, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
3 Alfred Wegener Institut für Polar-und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, Germany
Correspondence
Ying Xu
xuying{at}vub.ac.be
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) that differ in their degree of piezophily or piezotolerance (the prefix ‘piezo-’ denotes pressure; see Yayanos, 1995). Up to now, all cultivable psychropiezophiles have been found to be 
-proteobacteria of the genera Colwellia, Moritella, Photobacterium and Shewanella (Kato et al., 2000a; Barlett, 2000; Xu et al., 2003), none of which is confined to deep-sea environments, however. Abyssal archaea have also been reported (DeLong et al., 1994), but not yet cultivated.
In this study, we characterize a novel species of the recently described genus Psychromonas, which also belongs to the -subclass of the Proteobacteria. The type species, Psychromonas antarctica, was isolated from a high-salinity pond on the McMurdo ice-shelf (Mountfort et al., 1998). Another species, Psychromonas kaikoae, which is psychrophilic and obligately piezophilic, was retrieved from the Japan Trench (Nogi et al., 2002). A third species, Psychromonas marina, which is psychrophilic but not piezophilic, has also been described (Kawasaki et al., 2002).
Strain 2825T was isolated from Atlantic sediments on board the ship Meteor during the cruise GEOTROPEX '83 in August 1983. The water depth at the sampling station (latitude 16°56·1'N, longitude 17°55·5'W) was 2770 m and the temperature was 2·7 °C (Rüger & Tan, 1992). Samples were taken by means of a box-grab sampler with surface dimensions of 50x50 cm. Subsamples were drawn with a sterile corer from near the centre of the sediment surface in order to obtain unwarmed samples. Sediment from the upper 2 cm layer was suspended in cold 75 % sterile sea water and spread onto chilled sea-water agar plates prepared with a medium containing 1·5 g peptone, 0·5 g yeast extract, 0·01 g FePO4.4H2O, 750 ml sea water and 250 ml distilled water. Sampling and isolation methods have been described in detail by Rüger & Tan (1992).
The reference strains used in this study, P. antarctica DSM 10704T, P. kaikoae JT7304T and P. marina JCM 10501T, were grown as described by Nogi et al. (2002). High-pressure cultivation was performed in the DEEPBATH system at the Japan Marine Science and Technology Center (Kato et al., 1995) as reported previously (Yanagibayashi et al., 1999).
Growth or test media were Bacto Marine agar 2216 and Bacto Marine broth 2216 from Difco and the half-strength artificial sea-water, vitamin- and trace element-supplemented medium of Rüger (1988). Cardinal temperatures under high-pressure conditions were determined in Bacto Marine broth as described by Nogi & Kato (1999) by following total cell counts microscopically with a haematocytometer and culture samples fixed with formalin and stained with DAPI (4',6-diamidino-2-phenylindole).
Cells of strain 2825T are motile, Gram-negative rods. Under atmospheric pressure, cells are 0·9–1·2 µm wide and 2·0–5·5 µm long (Fig. 1). At the pressure where the maximal growth rate was observed (15–20 MPa at 6 °C; see Fig. 2), cells became slightly larger. At 50 MPa, which is about the limit at which cells still can grow at 6 °C, elongated forms were observed at low cell density.
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). The strain grew in the range from 2 to 12–13 °C (no temperature below 2 °C was tested). On plates, very faint growth was observed after 14 days at 18 °C but there was no growth at all at 19 °C. Between 4 and 8 °C, growth yields remained approximately the same (about 109 cells ml-1). No growth was observed in the absence of NaCl.
Strain 2825T is moderately piezophilic. At 6 °C, the best growth was obtained at 15–20 MPa, less than that observed at the depth of isolation (2770 m). At 10 °C, however, the pressure for maximal growth rose to about 25 MPa (Fig. 2b).
Strain 2825T was found to be facultatively anaerobic, oxidase-positive, chemo-organotrophic and prototrophic except for possible vitamin dependency (not tested). It produced acid from glucose and other carbohydrates (see Table 1 and the species description below) in the Minitek identification system (Becton Dickinson) (Rüger, 1981) and additionally, from glucose and lactose in Leifson's marine oxidation/fermentation medium (Leifson, 1963). It proved to be relatively oligotrophic: concentrations of 0·5 mg glucose, D-galactose or L-glutamate ml-1 already supported good growth on plates incubated at 4 °C on minimal medium supplemented with vitamins and trace elements (Rüger, 1988).
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The G+C content (Tamaoka & Komagata, 1984) of pure DNA (Saito & Miura, 1963) was 38·1 mol%, somewhat lower than observed for P. antarctica, P. marina and P. kaikoae (Table 1). The complete nucleotide sequence of the 16S rRNA gene was determined by direct sequencing of PCR-amplified DNA (Kato et al., 1998). It presented 96·9 and 97·5 % identity to sequences from Psychromonas sp. IC004 and P. antarctica DSM 10704T, respectively. Identities were higher with P. marina JCM 10501T (98·3 %) and P. kaikoae (98·6 %). On a distance phylogenetic tree constructed by the neighbour-joining method (Saitou & Nei, 1987) using the CLUSTAL W program (Thompson et al., 1994) without taking alignment gaps into consideration, the sequence was found to cluster with the 16S rRNA genes from the other Psychromonas species in a branch with high bootstrap support (Fig. 3). It is related to, but clearly distinct from, sequences from the genera Moritella, Shewanella and Photobacterium, which also comprise psychrophilic species found at different levels of the water column. In terms of similarity between sequences, the most closely related species were from the genera Photobacterium and Vibrio, with 90 % identity or less. The tree also contains Moritella abyssi and Moritella profunda, which are described in the accompanying paper (Xu et al., 2003).
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) from strain 2825T and P. antarctica DSM 10704T, P. marina JCM 10501T and P. kaikoae JCM 11054T and monitored by fluorimetry (Ezaki et al., 1989). Relatedness values all fell below 40 % (38, 38 and 24 % with P. antarctica, P. marina and P. kaikoae, respectively), while reciprocal values for the pairs P. antarctica/P. marina, P. antarctica/P. kaikoae and P. marina/P. kaikoae respectively averaged 48, 36 and 31 %. Since, by the current standard (Wayne et al., 1987), distinct species of the same genus should be related at <70 % DNA–DNA relatedness, the data indicate that strain 2825T represents a novel species of Psychromonas.
Whole-cell fatty acids were analysed as described by Nogi et al. (1998) from cells grown in Bacto Marine broth. Major fatty acids in strain 2825T were C14 : 1 (15 %), C16 : 0 (31 %) and C16 : 1 (44 %), a profile qualitatively similar to that of P. marina, which also displays small amounts of iso C16 : 0 and C22 : 6 (docosahexaenoic acid; DHA). P. kaikoae also contains C14 : 1 (10 %), C16 : 0 (15 %) and C16 : 1 (52 %) as major constituents, along with small amounts of both DHA and eicosapentaenoic acid, a distinctive feature of this species (Nogi et al., 2002). In P. antarctica, the predominant fatty acids are C16 : 0 (24 %), C16 : 1 (58 %) and C14 : 1 (8 %) (Nogi et al., 2002). The major isoprenoid quinone (Komagata & Suzuki, 1987; Nogi et al., 1998) is Q-8.
The general phenotypic and biochemical profile of strain 2825T is similar to those of P. kaikoae, P. antarctica and P. marina (Table 1). The main differences are the pressure response, strain 2825T being intermediate between P. kaikoae and P. antarctica, and the more strictly psychrophilic profile of strain 2825T.
The phenotypic and phylogenetic analysis of strain 2825T thus shows that it belongs to the recently described genus Psychromonas (Mountfort et al., 1998) and that it is sufficiently distant from the species already characterized to be considered as representing a novel species. We propose to call it Psychromonas profunda sp. nov. As with other members of the Vibrionaceae, it is facultatively anaerobic, capable of fermentative metabolism and is oxidase-positive. It is prototrophic except for possible vitamin dependency.
P. profunda is a strict psychrophile with a maximal growth rate at 3–4 °C under atmospheric pressure. As already noted for other psychropiezophiles (Yayanos, 1995; Abe et al., 1999; Kato et al., 2000b), growth of P. profunda at low temperature (6 °C) was enhanced at a pressure (15–20 MPa) lower than that found at the depth of isolation (28 MPa); moreover, incubating the cells at a higher temperature (10 °C) made them more piezophilic (the profile then peaked at about 25 MPa). This phenotype was also reported for thermopiezophiles retrieved from hydrothermal vents (Marteinsson et al., 1997). Such behaviour could be explained by any biological process that is slowed down by an increase in pressure but favoured by an increase in molecular mobility. An increase in temperature could counteract the ‘gelling’ effect of high pressure on membrane lipids (Marteinsson et al., 1997). It is also possible that pressure-induced compression critically affects the functioning of some enzymes in such a way that an increase in temperature can partially compensate for this effect.
Regarding the effects of pressure and temperature on proteins, psychropiezophiles are a living paradox since, on the one hand, efficient catalysis at low temperature requires high flexibility (at least in those parts of the molecules that are involved in the catalytic mechanism) and on the other hand, enzymes adapted to high pressure are expected to resist compression, thus to be more rigid (reviewed by Glansdorff & Xu, 2002). Some of these enzymes might be particularly sensitive to the opposite effects exerted by an increase in pressure and an increase in temperature. Furthermore, the difficulty in achieving such compromises may explain why abyssal psychropiezophiles grow relatively slowly. Careful nutritional studies will be required to test this proposal, but it is already noteworthy that ‘with increasing pressure-adaptation in barophilic (piezophilic) isolates, the maximum growth rates at optimum pressures decrease’ (Jannasch & Wirsen, 1984) (see also Yayanos et al., 1982; Yayanos, 1995). Very few studies of enzymes from psychropiezophiles have been carried out (Bartlett, 2000). The availability of closely related psychrophilic organisms adapted to different sections of the water column is of considerable interest to molecular biologists, since it provides a paradigm to analyse the basis of functional adaptation of cold-active enzymes to the whole range of hydrostatic pressures found in the piezosphere.
Members of the genus Psychromonas have been found in places as distant as the Antarctic coastal area (P. antarctica), the deep Atlantic at a northern tropical latitude (P. profunda) and the Japan Trench (P. kaikoae). This suggests that the evolution of the genus Psychromonas has been influenced by deep-ocean water circulation (Nogi et al., 2002). It would therefore be interesting to determine whether the same or only related species of Psychromonas also occur in the high Arctic. Until a short while ago, the general trend had been to observe the same genus but not the same species in the two polar domains (Staley & Gosink, 1999). In contrast, Rüger et al. (2000) reported that psychrophilic and psychrotolerant strains of the same species, Bacillus marinus, were indigenous to sediments of the Arctic and Antarctic oceans, the tropical Atlantic and the Iberian deep sea.
Description of Psychromonas profunda sp. nov.
Psychromonas profunda (pro.fun'da. L. fem. adj. profunda from the deep).
Cells are Gram-negative rods, either isolated or in pairs, 0·9–1·2 µm wide and 2·0–5·5 µm long, motile by means of a single, unsheathed and polar flagellum. On peptone/yeast extract/sea-water agar, colonies are smooth, colourless, translucent, irregular, punctiform and flat with an intact margin. Moderately halophilic (no growth observed in the absence of NaCl, normal growth with half-strength sea-water), strictly psychrophilic and moderately piezophilic. The temperature range for growth is 2 °C (or less, not tested) to 12–13 °C (14 °C on plates). Maximal growth is observed at 3–4 °C under atmospheric pressure. Growth is influenced favourably by pressure, with a maximum at 15–20 MPa at 6 °C and about 25 MPa at 10 °C. Facultatively anaerobic and prototrophic (with possible vitamin dependency, not tested) chemo-organotroph capable of both respiratory and fermentative metabolism. Catalase and cytochrome oxidase tests are positive. Nitrate is reduced to nitrite but no gas is produced. Indole and ONPG tests are positive. H2S is produced from cysteine. Susceptible to discs (Oxoid) containing 150 µg O/129, 2 U penicillin G, 10 µg tetracycline, 10 µg chloramphenicol, 50 µg furazolidone and 300 U polymyxin B. The major isoprenoid quinone is Q-8. Predominant cellular fatty acids are C14 : 1, C16 : 0 and C16 : 1. Acid is formed oxidatively and fermentatively from glucose, lactose, cellobiose, dulcitol (weakly), fructose, galactose, glycerol, inositol, maltose, mannitol, mannose, rhamnose, salicin, sucrose, trehalose and xylose; no acid from adonitol, arabinose, melibiose, raffinose or sorbitol. Within 4 weeks at 4 °C, utilizes cellobiose, galactose, gluconate, maltose, salicin, sucrose (weakly), trehalose, xylose, fumarate, succinate, mannitol (weakly), citrate, pyruvate, L-alanine, L-aspartate, glutamate and putrescine as sole carbon and energy sources but not arabinose, 
-D-glucose, mannose, ribose, propionate, adipate, 
-hydroxybutyrate, sorbitol, L-arginine, L-histidine, L-ornithine, p-hydroxybenzoate or quinate. Acetate, DL-lactate and glycerol are utilized only after prolonged incubation for up to 6 weeks. Starch is hydrolysed only weakly and gelatin not at all. Aesculin is hydrolysed and the DNase test is positive. Lipase, arginine dihydrolase, lysine decarboxylase and ornithine decarboxylase tests are negative. The DNA G+C content of the type strain is 38·1 mol%.
The type and only strain, strain 2825T (=LMG 21260T=JCM 11437T), was isolated from the upper layer of deep Atlantic sediments at a depth of 2770 m off the West African coast.
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ACKNOWLEDGEMENTS |
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REFERENCES |
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Bartlett, D. H. (2000). Microbial adaptations to the psychrosphere/piezosphere. In Molecular Marine Microbiology, pp. 185–201. Edited by D. H. Bartlett. Wymondham, UK: Horizon Scientific.
DeLong, E. F., Wu, K. Y., Prezelion, B. B. & Jovine, R. V. M. (1994). High abundance of archaea in Antarctic marine picoplankton. Nature 371, 695–697.[CrossRef][Medline]
Ezaki, T., Hashimoto, Y. & Yabuuchi, E. (1989). Fluorometric deoxyribonucleic acid-deoxyribonucleic acid hybridization in microdilution wells as an alternative to membrane filter hybridization in which radioisotopes are used to determine genetic relatedness among bacterial strains. Int J Syst Bacteriol 39, 224–229.
Glansdorff, N. & Xu, Y. (2002). Microbial life at low temperatures: mechanisms of adaptation and extreme biotopes. Implications for exobiology and the origin of life. Recent Res Dev Microbiol 6, 1–21.
Jannasch, H. W. & Wirsen, C. O. (1984). Variability of pressure adaptation in deep sea bacteria. Arch Microbiol 139, 281–288.[CrossRef]
Kato, C., Sato, T. & Horikoshi, K. (1995). Isolation and properties of barophilic and barotolerant bacteria from deep-sea mud samples. Biodivers Conserv 4, 1–9.
Kato, C., Li, L., Nogi, Y., Nakamura, Y., Tamaoka, J. & Horikoshi, K. (1998). Extremely barophilic bacteria isolated from the Mariana Trench, Challenger Deep, at a depth of 11,000 meters. Appl Environ Microbiol 64, 1510–1513.
Kato, C., Qureshi, M. & Horikoshi, K. (2000a). Pressure response in deep-sea piezophilic bacteria. In Molecular Marine Microbiology, pp. 175–184. Edited by D. H. Bartlett. Wymondham, UK: Horizon Scientific.
Kato, C., Nakasone, K., Qureshi, M. H. & Horikoshi, K. (2000b). How do deep-sea microorganisms respond to the environmental pressure? In Cell and Molecular Response to Stress, vol. 1, Environmental Stressors and Gene Responses, pp. 277–291. Edited by K. B. Storey & J. M. Storey. Amsterdam: Elsevier.
Kawasaki, K., Nogi, Y., Hishinuma, M., Nodasaka, Y., Matsuyama, H. & Yumoto, I. (2002). Psychromonas marina sp. nov., a novel halophilic, facultatively psychrophilic bacterium isolated from the coast of the Okhotsk Sea. Int J Syst Evol Microbiol 52, 1455–1459.[Abstract]
Komagata, K. & Suzuki K. (1987). Lipid and cell-wall analysis in bacterial systematics. Methods Microbiol 19, 161–207.
Leifson, E. (1963). Determination of carbohydrate metabolism of marine bacteria. J Bacteriol 85, 1183–1184.
Marteinsson, V. T., Moulin, P., Birrien, J., Gambacorta, A., Vernet, M. & Prieur, D. (1997). Physiological responses to stress conditions and barophilic behavior of the hyperthermophilic vent archaeon Pyrococcus abyssi. Appl Environ Microbiol 63, 1230–1236.
Morita, R. Y. (1975). Psychrophilic bacteria. Bacteriol Rev 39, 144–167.
Mountfort, D. O., Rainey, F. A., Burghardt, J., Kaspar, H. F. & Stackebrandt, E. (1998). Psychromonas antarcticus gen. nov., sp. nov., a new aerotolerant anaerobic, halophilic psychrophile isolated from pond sediment of the McMurdo ice shelf, Antarctica. Arch Microbiol 169, 231–238.[CrossRef][Medline]
Nogi, Y. & Kato, C. (1999). Taxonomic studies of extremely barophilic bacteria isolated from the Mariana Trench and description of Moritella yayanosii sp. nov., a new barophilic bacterial isolate. Extremophiles 3, 71–77.[CrossRef][Medline]
Nogi, Y., Kato, C. & Horikoshi, K. (1998). Moritella japonica sp. nov., a novel barophilic bacterium isolated from a Japan Trench sediment. J Gen Appl Microbiol 44, 289–295.
Nogi, Y., Kato, C. & Horikoshi, K. (2002). Psychromonas kaikoae sp. nov., a novel piezophilic bacterium from the deepest cold-seep sediments in the Japan Trench. Int J Syst Evol Microbiol 52, 1527–1532.[Abstract]
Rüger, H.-J. (1981). Comparison of the API and Minitek identification systems with conventional methods for differentiating marine bacteria. Veröff Inst Meeresforsch Bremerhav 19, 21–34.
Rüger, H.-J. (1988). Substrate-dependent cold adaptations in some deep-sea sediment bacteria. Syst Appl Microbiol 11, 90–93.
Rüger, H.-J. & Tan, T. L. (1992). Community structures of cold and low-nutrient adapted heterotrophic sediment bacteria from the deep eastern tropical Atlantic. Mar Ecol Prog Ser 57, 45–52.
Rüger, H.-J., Fritze, D. & Spröer, C. (2000). New psychrophilic and psychrotolerant Bacillus marinus strains from tropical and polar deep-sea sediments and emended description of the species. Int J Syst Evol Microbiol 50, 1305–1313.[Abstract]
Saito, H. & Miura, K. (1963). Preparation of transforming deoxyribonucleic acid by phenol treatment. Biochim Biophys Acta 72, 612–629.
Saitou, N. & Nei, M. (1987). The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol 4, 406–425.[Abstract]
Staley, J. T. & Gosink, J. J. (1999). Poles apart: biodiversity and biogeography of sea ice bacteria. Annu Rev Microbiol 53, 189–215.[CrossRef][Medline]
Tamaoka, J. & Komagata, K. (1984). Determination of DNA base composition by reverse-phase high-performance liquid chromatography. FEMS Microbiol Lett 25, 125–128.
Thompson, J. D., Higgins, D. G. & Gibson, T. J. (1994). CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighing, position-specific gap penalties and weight matrix choice. Nucleic Acids Res 22, 4673–4680.
Wayne, L. G., Brenner, D. J., Colwell, R. R. & 9 other authors (1987). Report of the ad hoc committee on reconciliation of approaches of bacterial systematics. Int J Syst Bacteriol 37, 463–464.
Xu, Y., Nogi, Y., Kato, C., Liang, Z., Rüger, H.-J., De Kegel, D. & Glansdorff, N. (2003). Moritella profunda sp. nov. and Moritella abyssi sp. nov., two psychropiezophilic organisms isolated from deep Atlantic sediments. Int J Syst Evol Microbiol 53, 533–538.
Yanagibayashi, M., Nogi, Y., Li, L. & Kato, C. (1999). Changes in the microbial community in Japan Trench sediment from a depth of 6292 m during cultivation without decompression. FEMS Microbiol Lett 170, 271–279.[CrossRef][Medline]
Yayanos, A. A. (1995). Microbiology to 10,500 meters in the deep sea. Annu Rev Microbiol 49, 777–805.[CrossRef][Medline]
Yayanos, D. A., Dietz, D. S. & Van Boxtel, R. (1982). Dependence of reproduction rate on pressure as a hallmark of deep-sea bacteria. Appl Environ Microbiol 44, 1356–1361.
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) and 10 (
) °C. The growth rate, µ, is calculated as 1/td [td is doubling time (h)].