Difference between revisions of "Colwellia psychrerythraea"
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Revision as of 17:51, 7 May 2007
A Microbial Biorealm page on the genus Colwellia psychrerythraea
Higher order taxa
Bacteria; Proteobacteria; Gammaproteobacteria; Alteromonadales; Colwelliaceae; Colwellia
Strain: 34H / ATCC BAA-681
Description and significance
Colwellia psychrerythraea is considered an obligate psychrophile and appears rod-shaped and red in pigment. This flagella-containing organism can be found in continually cold marine environments including Arctic and Antarctic sea ice. Strain 34H, in particular, was isolated from Arctic marine sediments. It has a growth temperature range of -1°C to 10°C. Optimal growth appears at 8°C, with maximum cell yield occurring at the subzero temperature of -1°C. Cells are able to swim in temperatures as low as -10°C. Growth can occur under deep sea pressures as well.
Sequence completion of this genome has revealed Colwellia's significant role in bioremediation, carbon and nutrient cycling, production of secondary metabolites, and cold-adapted enzymes. C. psychrerythraea is considered a model organism for the study of life in permanently cold environments, specifically bacterial adaptations. These adaptations include production of extracellular polymeric material for purposes of biofilm formation and cryoprotection, as well as enzymes with the ability to breakdown high-molecular-weight organic compounds. Particularly unique to this organism is the production of cold-active enzymes which show distinct heat instability and optimal activity occurring at low temperatures. These features make Colwellia species important in carbon and nutrient cycling in the cold marine environments in which they inhabit. From contaminated sediments to ice formations, observation of this organism can possibly give insight into earlier Earth environments as well as those on other planets and moons.
The complete genome of Colwellia psychrerythraea 34H has been sequenced and shown to be 5,373,180 nucleotides in length. The genome consists of one circular chromosome which codes for 117 structural RNAs and 4910 proteins. The circular DNA contains 38% guanine-cytosine base pairing.
Comparative genome analyses proposes that the psychrophilic behavior stems from a set of synergistic modifications in the overall genome content and amino acid composition, rather than a specific collection of genes responsible for such cold adaption.
Cell structure and metabolism
This rod-shaped organism is enclosed by two cell membranes and contains flagella for motility. Important adaptations to its survival in such cold environments include production of extracellular polysaccharides which have cryoprotection purposes, as well as a large amount of extracellular enzymes which may play a role in the metabolism of dissolved organic carbon at low temperatures.
Other cell features characteristic to cold adaption involve cell membrane fluidity and coding sequences for polyunsaturated fatty acid synthesis as well as a fatty acid cis/trans isomerase, which both aide in increasing cell membrane fluidity. Genomic investigations also showedC. psychrerythraeaproduces polyhydroxyalkanoate (PHA) compounds, which function in intracellular carbon and energy storage. Means of nitrogen storage was also identified in the production cyanophycin-like compounds, which serve as nitrogen reserves. Production of both of these compounds insures important intracellular carbon and nitrogen reserves when such cold environments may set limitations on such uptake.
C. psychrerythrea's unique cold adaptations such as the ability to breakdown high molecular weight compounds and carbon metabolism make this organism important in carbon and nutrient cycling in such cold marine environments. Detoxification activities by this organism may aide in bioremediation of cold habitats as well.
This organism is not known to be pathogenic.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Enter summaries of the most recent research here--at least three required
Barbara A. Methé, Karen E. Nelson, Jody W. Deming, Bahram Momen, Eugene Melamud, Xijun Zhang, John Moult, Ramana Madupu, William C. Nelson, Robert J. Dodson, Lauren M. Brinkac, Sean C. Daugherty, Anthony S. Durkin, Robert T. DeBoy, James F. Kolonay, Steven A. Sullivan, Liwei Zhou, Tanja M. Davidsen, Martin Wu, Adrienne L. Huston, Matthew Lewis, Bruce Weaver, Janice F. Weidman, Hoda Khouri, Terry R. Utterback, Tamara V. Feldblyum, and Claire M. Fraser. "The psychrophilic lifestyle as revealed by the genome sequence of Colwellia psychrerythraea 34H through genomic and proteomic analyses." Proceedings of the National Academy of Sciences, vol. 102: 10913-10918; published online before print as 10.1073/pnas.0504766102
Karen Junge, Hajo Eicken, and Jody W. Demin. "Motility of Colwellia psychrerythraea Strain 34H at Subzero Temperatures." Applied Environmental Microbiology. 2003 July; 69(7): 4282–4284. doi: 10.1128/AEM.69.7.4282-4284.2003.
Edited by Jaclyn Gaede; student of Rachel Larsen and Kit Pogliano