Chromohalobacter Salexigens

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A Microbial Biorealm page on the genus Chromohalobacter Salexigens

Classification

Higher order taxa

Bacteria; Proteobacteria; Gammaproteobacteria; Oceanospirillales; Halomonadaceae; Chromohalobacter;

NCBI: Taxonomy Genome

Species

C. salexigens

Description and significance

This bacterium is a moderate halophile, meaning it has much to do with saline, yet does not require high concentrations of sodium chloride. C. salexigens is very flexible in that its salt requirements can be met by ions of other salts such as potassium, rubidium, ammonium, bromide, and others.

Genome structure

DNA Bases: 3696649

Chromosome Type: Circular

Total Genes: 3403

Protein Coding Genes: 3319
RNA Genes:              84
Pseudo Genes:           21

Cell structure and metabolism

C. salexigens is a moderate halophile that is capable of "making a living" in many various salt environments. In this way, it is a flexible bacterium. Placing C. salexigens in media containing a 0.3M concentration of NaCL and a 0.7M concentration of (Na+, K+, Rb+, etc...) will stimulate its growth positively. [2]

Ecology

C. salexigens produces and stores small amounts of ectoine and glycerol intracellularly. Small-scale production of these and other organic solutes is made possible via this organism. [3]

Interactions between C. salexigens and other bacteria such as various strands of Salmonella allow for salinity tolerance modulation. In other words, this bacterium allows for other organisms to exist in environments they would otherwise not be able to cope with.

Pathology

Current research indicates that C. salexigens is not known to be pathogenic.

Application to Biotechnology

In response to salt and temperature stress C. salexigens produces and stores various solutes. Some solutes, namely hydroxyectoine, are used in thermoregulation processes that protect C. salexigens from extreme temperatures. [3]

Current Research

Research is being done on mutant C. salexigens bacterium that synthesize ectoine. C. Salexigens mutants such as these can be used to produce N(gamma)-acetyl-2,4-diaminobutyrate (NADA). When said mutants are placed in conjunction with the bacterium Salmonella Enterica Serovar Typhimurium, salinity stress typically present in this form of Salmonella ceased to persist. [4]

In other research, C. Salexigens is being investigated to better understand its long-term response to salinity stress regarding membrane modulation. Ectoine-deficient strains of C. salexigens are unable to cope with salinity stress and undergo extensive membrane changes. The addition of ectoine to these deficient strains, however, allows these bacterium to maintain a salinity responsive membrane. [5]

References

[1] Stothard P, Van Domselaar G, Shrivastava S, et. al. 2005. BacMap: an interactive picture atlas of annotated bacterial genomes. Nucleic Acids Res 33:D317-D320

[2] O'Connor K, Csonka LN. 2003. Salt Requirements of C. Salexigens. Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392.

[3] Garcia-Estepa R, Argandona M, Reina-Bueno M, et. al. 2006. Thermoprotection of C. Salexigens. Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Spain.

[4] Garcia-Estepa R, Canovas D, Iglesias-Guerra F, et. al. 2006. Osmoprotection of Salmonella Enterica. Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Spain.

[5] Vargas C, Kallimanis A, Koukkou AI, et. al. 2005. NADA, the Precursor to Ectoine. Department of Microbiology and Parasitology, University of Seville, Spain.

Edited by Chris Wittrock, a student of Rachel Larsen and Kit Pogliano