The psychrophilic lifestyle as revealed by the genome sequence of Colwellia psychrerythraea 34H through genomic and proteomic analyses

Abstract

The completion of the 5,373,180-bp genome sequence of the marine psychrophilic bacterium Colwellia psychrerythraea 34H, a model for the study of life in permanently cold environments, reveals capabilities important to carbon and nutrient cycling, bioremediation, production of secondary metabolites, and coldadapted enzymes. From a genomic perspective, cold adaptation is suggested in several broad categories involving changes to the cell membrane fluidity, uptake and synthesis of compounds conferring cryotolerance, and strategies to overcome temperature-dependent barriers to carbon uptake. Modeling of three-dimensional protein homology from bacteria representing a range of optimal growth temperatures suggests changes to proteome composition that may enhance enzyme effectiveness at low temperatures. Comparative genome analyses suggest that the psychrophilic lifestyle is most likely conferred not by a unique set of genes but by a collection of synergistic changes in overall genome content and amino acid composition.proteome ͉ psychrophily ͉ bioremediation ͉ astrobiology ͉ threedimensional homology modeling

A Unique Capsular Polysaccharide Structure from the Psychrophilic Marine Bacterium Colwellia psychrerythraea 34H That Mimics Antifreeze (Glyco)proteins

“…C. psychrerythraea 34H has been considered a model for the study of bacterial growth and survival strategies in cold marine environments. 22 The synthesis of extracellular polysaccharides appears to be important to cold-adaptation of this strain, especially in subfreezing environments. 12,17,23,24 Data reported here unravel the structure of a capsular polysaccharide surrounding individual cells of C. psychrerythraea 34H (Figure 1), which in turn defines the organism's interface with its environment.…”

Terrestrial models for extraterrestrial life: methanogens and halophiles at Martian temperatures

“…These species are not capable of growth at temperatures below x10 xC, and therefore do not rival bacterial species such as Colwellia psychrerythraea, with an extrapolated minimum growth temperature of x14.5 xC (Methe et al 2005). Nonetheless, the behaviour shown by the individual methanogens and halophiles targeted by our investigation may shed light on more general survival strategies adopted by these important archaeal species at low temperatures.…”

“…The cells are encased in a polymeric matrix of undefined chemical composition (Rudolph et al 2001), which appears to be synthesized by euryarchaeon SM1 as a pili-like fibre that emanates radially from the cell mediating cell-cell and possibly cellsurface interactions (Moissl et al 2003). Sea-ice microorganisms, including Colwellia psychrerythraea, are also reported to produce extracellular polymeric substances (EPS) as buffering and cryoprotective agents at temperatures as low as x20 xC (Krembs et al 2002 ;Methe et al 2005). Collectively, these data indicate that synthesis of extracellular materials has evolved as a mechanism of cold adaptation in phylogenetically diverse microorganisms.…”

High bicarbonate assimilation in the dark by Arctic bacteria

“…The high bicarbonate incorporation for this group could be related to the detection of a variety of accC sequences encoding different putative biotin carboxylases affiliated with a psychrophilic strain of this group: Colwellia psychrerythraea 34H (Table 1). The analysis of the genome of this bacterium has shown that it can metabolize complex organic substrates and possibly C1 compounds (Methé et al, 2005), and the metabolic use of C1 compounds is known to enhance CO 2 assimilation (Doronia and Trotsenko, 1985). A similar rationale could apply to the betaproteobacterial phylotypes identified in the clone libraries affiliated with Methylophylales, which also use C1 compounds in their metabolism, explaining the high number of bicarbonate-incorporating Betaproteobacteria detected in the autoradiograms.…”