Psychromonas arctica sp. nov., a novel psychrotolerant, biofilm-forming bacterium isolated from Spitzbergen

Abstract

Using starch as a carbon source at a cultivation temperature of 4˚C, a number of Gram-negative, aerobic strains was isolated from sea-ice and sea-water samples collected at Spitzbergen in the Arctic. Analysis of the genetic diversity of the novel isolates by random amplification of polymorphic DNA (RAPD) and ERIC fingerprinting revealed a homogenic group of biofilm-forming bacteria that contained small extrachromosomal elements. As a representative of the group, strain Pull 5.3 T ,isolated from a sea-water sample, was used for detailed characterization. In recent years, increasing attention in research has been directed to cold-adapted micro-organisms that are able to grow at or close to the freezing point of water, namely psychrophiles. They are defined by an optimal temperature for growth of about 15˚C or below, a maximal growth temperature of about 20˚C and the ability to grow at 0˚C (Morita, 1975). In comparison, psychrotolerant microorganisms, sometimes also referred to as 'psychrotrophs', generally have optimum and maximum growth temperatures of 20˚C or above (Ingraham & Stokes, 1959).Cold-adapted micro-organisms are found in both permanently and temporarily cold habitats, which comprise more than 80 % of the Earth's biosphere. Oceans, covering threequarters of the Earth, polar regions (14 % of the Earth's surface), high mountains and deep lakes provide various aquatic and terrestrial cold environments where the temperature seldom or never reaches 5˚C (Gounot, 1999). The ability of micro-organisms to grow at low temperatures is not restricted to prokaryotes. A wide variety of micro-organisms, including bacteria, archaea, yeast, fungi and algae, is found in cold environments. These microorganisms are free-living in soil and fresh and saline waters or are associated with plants and cold-blooded animals such as fish or crustaceans. Among the bacteria, almost all types have been identified either after isolation (Ravenschlag et al., 1999; Bowman et al., 1997) or by detection in their natural habitats using a 16S rRNA approach (Fuhrman et al., 1993;DeLong et al., 1994;Vetriani et al., 1998). Unlike hyperthermophiles, they do not belong to new phyla. The majority of psychrophiles studied to date belong to the Gram-negative Proteobacteria. This is not surprising, since Gram-negatives are predominant in marine waters, where most investigations have been performed.Psychrophiles and psychrotolerant micro-organisms have a wide range of adaptations, including alterations in the protein and lipids of their membrane, energy-generation systems, protein synthesis and hydrolytic enzymes (Russell, 1998). Higher specific activity at low temperatures and thermosensitivity of cold-active enzymes provide a valuable source for exploration of novel biotechnological processes (Feller & Gerday, 1997). Since it has become clear that psychrophiles also represent a naturally occurring model for investigating protein adaptation to cold (Aghajari et al., 1998), an increasing number of novel bacterial strains from different Arctic and A...

Psychromonas japonica sp. nov., Psychromonas aquimarina sp. nov., Psychromonas macrocephali sp. nov. and Psychromonas ossibalaenae sp. nov., psychrotrophic bacteria isolated from sediment adjacent to sperm whale carcasses off Kagoshima, Japan

“…The genus includes piezophilic and halophilic species that are widely distributed in nature, especially in aquatic environments such as polar sea ice, high-salinity ponds and the ocean (Kawasaki et al, 2002;Nogi et al, 2002;Groudieva et al, 2003;Xu et al, 2003;Auman et al, 2006;Nogi, 2007). Seven species of the genus Psychromonas have been described to date.…”

Psychromonas heitensis sp. nov., a psychrotolerant bacterium isolated from seawater in Japan

“…Some piezophilic bacteria are also included in this genus (Brenner et al, 2005). Members of the genus Psychromonas have been isolated from cold environments, including polar regions [Psychromonas antarctica (Mountfort et al, 1998), P. arctica (Groudieva et al, 2003) and P. ingrahamii (Auman et al, 2006)], deep-sea sediments [P. kaikoae , P. profunda (Xu et al, 2003) and P. hadalis (Nogi et al, 2007) and drifting ice [P. marina (Kawasaki et al, 2002)]. In this study, four psychrotolerant strains isolated from Heita Bay off Kamaishi in Japan were analysed.…”

“…nov.); 2, P. antarctica DSM 10704 T ; 3, P. arctica Pull 5.3 T ; 4, P. hadalis K41G T ; 5, P. ingrahamii 37 T ; 6, P. kaikoae JT7304 T ; 7, P. marina 4-22 T ; 8, P. profunda 2825 T . Data are from this study, Kawasaki et al (2002), Groudieva et al (2003), Auman et al (2006) and Nogi et al (2007 …”

Psychromonas boydii sp. nov., a gas-vacuolate, psychrophilic bacterium isolated from an Arctic sea-ice core

“…+, Positive; 2, negative; W, weakly positive after 3 weeks; (W), weakly positive after 6 weeks; NR, not reported; ND, not determined. Data are from this study, Auman et al (2006), Breezee et al (2004), Brenner et al (2005), Groudieva et al (2003), Hosoya et al (2008), Kawasaki et al (2002), Miyazaki et al (2008), Mountfort et al (1998), Nogi et al (2002Nogi et al ( , 2007, Riley et al (2008) and Xu et al (2003).…”

“…All members are Gram-negative rods exhibiting cold-temperature aerobic growth, an optimum salt concentration of greater than 0 %, a DNA G+C content around 40±3 mol% and membranes that are enriched in 16-carbon saturated and unsaturated fatty acids (Auman et al, 2006;Breezee et al, 2004;Brenner et al, 2005;Groudieva et al, 2003;Hosoya et al, 2008;Kawasaki et al, 2002;Miyazaki et al, 2008;Mountfort et al, 1998;Nogi et al, 2002Nogi et al, , 2007Xu et al, 2003). Beyond these similarities, members of the genus Psychromonas described to date have a great deal of variety in their other physiological characteristics including cell size, temperature range for growth, piezophily, presence of gas vacuoles and carbon source utilization.…”