Psychrobacter cryohalolentis

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1. Classification

Higher Order Taxa: Bacteria; Proteobacteria; Gammaproteobacteria; Pseudomonadales; Moraxellaceae; Psychrobacter; Psychrobacter cryohalolentis

2. Description and Significance

Psychrobacter is a genus within the gamma proteobacteria. They are capable of reproduction at temperatures ranging from –10 to 37 °C. Psychrobacter cryohalolentis is an aerobic, halotolerant, non-motile, psychrophilic, and radiation resistant bacteria(Juni & Heym 1986).

3. Genome structure

The genome of Psychrobacter cryohalolentis K5 has been completely sequenced. It contains 2,575 genes and approximately 3.1Mb in size (Bakersman, C. et al., 2006).

4. Cell structure and metabolism

Psychrobacter cryohalolentis are small, gram-negative, non-motile, non-pigmented, non-spore-forming coccobacilli, which often found in pairs (Bakersman, C. et al., 2004). Psychrobacter cryohalolentis is 0.9–1.3 µm long and 0.5–0.8 µm wide. Growth usually occurs at –10 to 30 °C. Their optimal growth temperature is 22 °C. Colonies on marine agar are about 2 mm in diameter, smooth, opaque and circular after 5 days at 20 °C. NaCl is not required for growth, but growth occurs in 1.7 M NaCl. Strictly aerobic; the oxidase test is positive. Acid is not produced from carbohydrates. Cells are not able to reduce nitrate to nitrite. Urease and tryptophan deaminase are not produced. The main cellular fatty acids are 18 : 1 7c and 16 : 1 7c. The G+C content of DNA of the type strain is 42.3 mol%. (Bakersman, C. et al., 2006).

5. Ecology

Psychrobacter cryohalolentis strain K5T, was isolated from a cryopeg within permafrost in the Kolyma lowland, Siberia, Russia (Bakersman, C. et al., 2006). This K5 strain was selected because of its ability to reproduce at -10 °C with a generation time of 39 days and rapid growth at low temperatures (Bakersman, C. et al., 2004).

6. Pathology

Little is known about whether this species causes infections. However, there are some close relatives of Psychrobacter cryohalolentis which are isolated from infections, such as Psychrobacter pulmonis sp. which is isolated from lung infection in sheep (Fernández-Garayzábal, 2003), and Psychrobacter immobilus which is isolated from the eye, brain tissue, urethra, cerebral spinal fluid, and blood, which lead some scientists suspect that these bacteria may be the cause of opportunistic infections in some patients (Gini, 1990).

7. Application to biotechnology

There is no information found for the application to biotechnology.

8. References

1. Juni, E. and G.A. Heym, Psychrobacter immobilis gen. nov., sp. nov.: Genospecies composed of Gram-negative, aerobic, oxidase-positive coccobacilli. International Journal of Systematic Bacteriology, 1986. 36 (3): p. 388-391
2. Psychrobacter cryohalotensis. Doe Joint Genome Institute, U.S. Department of Energy #REDIRECT [[1]]
3. Bakermans, C., et al., Psychrobacter cryohalolentis sp. nov. and Psychrobacter arcticus sp. nov., isolated from Siberian permafrost. International Journal of Systematic Evolutionary Microbiology vol 56, 2006: p. 1285-1291.
4. Bakermans, C., et al., Reproduction and metabolism at -10°C of bacteria isolated from Siberian permafrost. Environmental Microbiology vol 5(4), 2003: p. 321-326.
5. Bakermans, C. and K.H. Nealson, Relationship of critical temperature to macromolecular synthesis and growth yield in Psychrobacter cryopegella. Journal of Bacteriology, 2004. 186 (8): p. 2340-2345.
6. Bakermans, C., et al., Cold acclimation proteins expressed at subzero temperatures by a Psychrobacter isolated from Siberian permafrost. Environmental Microbiology, 2004.
7. Fernández-Garayzábal, J. F., et al., Psychrobacter pulmonis sp. nov., isolated from the lungs of lambs. International Journal of Systematic Evolutionary Microbiology vol 53, 2003: p. 415-419
8. Gini, G.A., Ocular infection caused by Psychrobacter immobilis acquired in the hospital. Journal of Clinical Microbiology, 28(2) February 1990: p.400–401

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