Ralstonia metallidurans
A Microbial Biorealm page on the genus Ralstonia metallidurans
Classification
Higher order taxa
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Beta Proteobacteria
Order: Burkholderiales
Family: Ralstoniaceae
Genus: Ralstonia
Species: R. metallidurans
[Others may be used. Use NCBI link to find]
Species
|
NCBI: Taxonomy |
Genus species Ralstonia metallidurans
Description and significance
Ralstonia metallidurans is a gram-negative, non-spore forming bacillus that flourishes in millimolar concentrations of toxic heavy metals. It and other metal-resistant members of the genus Ralstonia are frequently found in sediments and soils with a high content of heavy metals from diverse geographical locations. The reference strain, CH34, was first isolated in 1976 from the sludge of a zinc decantation tank in Belgium that was polluted with high concentrations of several heavy metals. Ralstonia metallidurans was identified by Frank Reith of Australian National University and his colleagues as the common denominator among bacteria comprising a dried organic biofilm found on the surface of gold grains collected from a park and gold mines in southern New South Wales and northern Queensland, Australia. Reith further isolated and grew the bacteria in the lab and found that R. metallidurans have the unique ability to precipitate gold. According to Reith, "A unique attribute of R. metallidurans is that it is able to survive in concentrations of gold that would kill most other micro-organisms." Metals like gold are normally toxic to bacteria. It is still unknown exactly how the bacteria help to precipitate the gold grains, but is possible that the microbe screens out the gold as part of an effort to detoxify its immediate environment. Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.
Genome structure
A typical feature of these metal-resistant Ralstonia is the presence of one or two large megaplasmids which contain genes for multiple resistances to heavy metals. The reference strain, CH34, contains two large plasmids, pMOL28 (180 kb) and pMOL30 (240 kb). Together these plasmids confer resistance to Zn, Cd, Co, Pb, Cu, Hg , Ni and Cr. Both plasmids are low copy number and stably maintained even without selective pressure. They are self-transferable at low frequencies.
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?
Cell structure and metabolism
Its optimal growth temperature is 30 çC.
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
Enter summaries of the most recent research here--at least three required
References
Edited by student of Rachel Larsen and Kit Pogliano
