Psychrobacter luti
Classification
Genus: Psychrobacter
Bacteria; Proteobacteria; Gammaproteobacteria; Pseudomonadales;Moraxellaceae; Psychrobacter.
Species
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NCBI: Taxonomy |
Psychrobacter luti
Description and Significance
Psychrobacter was created by Juni & Heym (1986) to accommodate a group of non-motile, oxidase-positive, non-pigmented, chiefly psychrotolerant, Gram-negative rods or coccobacilli isolated from the skin of fish and chickens and from various processed foods.
Psychrobacter organisms thrive in cold environments which constitute an ecological niche. A source of Psychrobacter organisms is Anarctic environments.
The type strain, strain NF11T (=LMG 21276T=CECT 5885T), was isolated from muddy soil collected from the inlet Admiralty Bay on King George Island, South Shetland Islands, Antarctica.
Describe the appearance, habitat, etc. of the organism, and why you think it is important.
Genome Structure
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Psychrobacter luti strain LMG 21276 DNA gyrase subunit B(gyrB)gene, partial cds. 2238 bp of DNA in a linear structure isolated from Siberian permafrost.(Bakermans,C et al 2005).
Psychrobacter luti strain NF11 16S ribosomal RNA, partial sequence. 1491 bp of rRNA in a linear structure. (Bozal,N 2008)
Cell Structure, Metabolism and Life Cycle
The isolates were oxidase-positive, halotolerant, Gram-negative,considerable halotolerance, non-motile coccobacilli with a strictly oxidative metabolism.
Neither diffusible pigments nor bioluminescence were observed. The cells of all bacterial isolates presented capsules and were about 0.4–1.8 by 0.4–0.8 mm in size.
The strains were moderately halophilic and tolerated NaCl levels of about 9.5–12.5%.
whereas colonies of NF11T, NF18, NF19 and NF20 were smooth, opaque, non-circular and spread little throughout the growth medium, with similar dimensions.
The pH range for growth was 6–9.5 and the growth temperature range was 4–30 oC for all the strains isolated
All strains were oxidase- and catalase-positive and capable of oxidative metabolism.
Except for strain NF11T, all the strains possessed urease activity. Does not
Strains NF11T, NF18, NF19 and NF20 reduced nitrate to nitrite.
deaminated phenylalanine
-None of the strains was capable of deaminating tryptophan.
-sensitive to penicillin.
-possessed L-alanine aminopeptidase, again indicating their Gramnegative character.
Able to grow in the absence of NaCl and
-can tolerate 9.5% (w/v) NaCl
Ecology and Pathogenesis
"Psychrobacter luti" thrives in the cold extremes of the biosphere. Cold (psychrotolerant) and salty (halotolerant) environments are its ecological niche with places such as Antarctic glacier mud serve as a prime environment for its livelihood. Many scientist infer that these subzero temperatures of Antarctica create environment where very little to no microbial activity is observed. This is not true when such microbes as "P. luti" were discovered as being microbes that not only survive in these environments, but maintain a consisted, often growing microbial biomass. However, the environment Psychrobacter relatives are found in are not always extremes such as Antarctica.
Another Psychrobacter found in very similar environmets is "Psychrobacter glacincola". According to a study done by Ringo et al., "P. glacincola" is also found in the gastrointestinal tract of Atlantic cod fed soybean meal. According to another study done by Li et al, both "P. luti" and "P. glacincola" are in the upper 90% in having a similar genome to the microbes found in South China sea sponges (only in the colder times of the year).
"P. luti" is one of the prime reducers of nitrate to nitrite. Also, with the use of oxidase and catalase in its striclty aerobic metabolism, it provides oxygen, water, and hydrogen peroxide to other microbes. Since there are these microbial biomasses present in the glacier mud of Antarctica, the biomass often prevents freezing at all depths of the mud, just as the lakes of Antarctica, but also a cohesive attribute which can hold glacier mud bound.
References
National Center for Biotechnology Information, U.S. National Library of Medicine 8600 Rockville Pike, Bethesda MD, 20894 USA
Author
Page authored by Hahyung Y. Kim and Benjamin Kamphuis, student of Prof. Jay Lennon at Michigan State University.
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