Ralstonia metallidurans

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Ralstonia metallidurans

Kingdom:	Bacteria
Phylum:	Proteobacteria
Class:	Beta Proteobacteria
Order:	Burkholderiales
Family:	Ralstoniaceae
Genus:	Ralstonia

Binomial name

Ralstonia metallidurans
Goris et al. 2001

Ralstonia metallidurans strain CH34, [previously Alcaligenes eutrophus, (Goris et al. 2001)] non-spore forming bacillus is adapted to survive several forms of heavy metal stress (Nies 1999, 2000). Therefore, it is our subject to develop bionomy by looking at heavy metal disturbance of cellular processes. This bacterium shows a unique combination of advantages not present in this form in other bacteria. (

i) Its genome has been fully sequenced (Preliminary, unnotated sequence data were obtained from the DOE JointGenome Institute (JGI) at http://www.jgi.doe.gov/tempweb/JGI_microbial/html/index.html).

(ii) It is non-pathogenic, therefore, models of the cell can also be tested in artificial environments similar to the natural habitats of this bacterium.

(iii) It is related to the plant pathogen R. solanacearum (Salanoubat et al. 2002).

(iv) It is of ecological importance since related bacteria are predominant in mesophilic heavy metal-contaminated environments (Diels et al. 1995a; Goris et al. 2001).

(v) It is of industrial importance and used for heavy metal remediation and sensing (Nies 2000).

(vi) It is an aerobic chemolithoautotroph, facultatively able to grow in a mineral salts medium in the presence of H2, O2 and CO2 without an organic carbon source (Mergeay et al. 1985). The energy providing subsystem of the cell under these conditions is composed only of the hydrogenases, the respiratory chain and the F1F0-ATPase. This keeps this subsystem simple and clearly separated from the anabolic subsystems that starts with the Calvin cycle for CO2-fixation.

(vii) It is able to degrade xenobiotics even in the presence of high heavy metal concentrations (Springael et al. 1993).

(viii) Finally, strain CH34 is adapted to the outlined harsh conditions by a multitude of heavy metal resistance systems that are encoded by the two indigenous megaplasmids pMOL28 and pMOL30 or the bacterial chromosome(s) (Nies 1999, 2000).

Also it plays a vital role in the formation of gold,^[1] a metal highly toxic to most other microorganisms.

[edit] References

^[2] ^[3] ^[4] ^[5] ^[6] ^[7] ^[8]

^ Frank Reith, Stephen L. Rogers, D. C. McPhail, and Daryl Webb, "Biomineralization of Gold: Biofilms on Bacterioform Gold", Science, vol. 313, no. 5784 (14 July 2006): 233-236. (abstract and author contact)
^ Goris J et al.,(2001) Classification of metal-resistant bacteria from industrial biotopes as Ralstonia campinensis sp. nov., Ralstonia metallidurans sp. nov. and Ralstonia basilensis Steinle et al. 1998 emend. Int J Syst Evol Microbiol 51: 1773–1782.
^ Nies DH (1999) Microbial heavy metal resistance. Appl Microbiol Biotechnol 51: 730–750.
^ Nies DH (2000) Heavy metal resistant bacteria as extremophiles: molecular physiology and biotechnological use of Ralstonia spec. CH34. Extremophiles 4: 77–82.
^ Salanoubat M et al.,(2002) Genome sequence of the plant pathogen Ralstonia solanacearum. Nature 415: 497–502.
^ Diels L, Dong Q, van der Lelie D, BaeyensW&MergeayM(1995a)The czc operon of Alcaligenes eutrophus CH34: from resistance mechanism to the removal of heavy metals. J Indust Microbiol 14: 142–153.
^ Mergeay M, Nies D, Schlegel HG, Gerits J, Charles P & van Gijsegem F (1985) Alcaligenes eutrophus CH34 is a facultative chemolithotroph with plasmid-bound resistance to heavy metals. J Bacteriol 162: 328–334.
^ Springael D, Diels L, Hooyberghs L, Kreps S & Mergeay M (1993) Construction and characterization of heavy metal resistant haloaromatic-degrading Alcaligenes eutrophus strains. Appl Environ Microbiol 59: 334–339.