Cupriavidus metallidurans strain CH34, (renamed from Ralstonia metallidurans and previously known as Ralstonia eutropha and Alcaligenes eutrophus) is a non-spore-forming bacillus

Bacillus

Bacillus is a genus of Gram-positive, rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species...

 which is adapted to survive several forms of heavy metal stress. Therefore, it is an ideal subject to study heavy metal disturbance of cellular processes. This bacterium shows a unique combination of advantages not present in this form in other bacteria.

• Its genome
  Genome
  In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
  
   has been fully sequenced (Preliminary, unnotated sequence data were obtained from the DOE Joint Genome Institute
  Joint Genome Institute
  The U.S. Department of Energy Joint Genome Institute was created in 1997 to unite the expertise and resources in genome mapping, DNA sequencing, technology development, and information sciences pioneered at the DOE genome centers at Lawrence Berkeley National Laboratory , Lawrence Livermore...
  
   (JGI)).
• It is non-pathogenic
  Pathogen
  A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
  
  , therefore, models of the cell can also be tested in artificial environments similar to the natural habitats of this bacterium.
• It is related to the plant pathogen Ralstonia solanacearum
  Ralstonia solanacearum
  Ralstonia solanacearum is an aerobic non-sporing, Gram-negative plant pathogenic bacterium. R. solanacearum is soil-borne and motile with a polar flagellar tuft. It colonises the xylem, causing bacterial wilt in a very wide range of potential host plants...
  
  .
• It is of ecological
  Ecology
  Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
  
   importance since related bacteria are predominant in mesophilic
  Mesophile
  A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, typically between 25 and 40 °C...
  
   heavy metal-contaminated environments.
• It is of industrial importance and used for heavy metal remediation and sensing.
• It is an aerobic
  Aerobic organism
  An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment.Faculitative anaerobes grow and survive in an oxygenated environment and so do aerotolerant anaerobes.-Glucose:...
  
   chemolithoautotroph, facultatively able to grow in a mineral salts medium in the presence of H₂, O₂
  Oxygen
  Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
  
   and CO₂
  Carbon dioxide
  Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
  
   without an organic carbon source. The energy providing subsystem of the cell under these conditions is composed only of the hydrogenase
  Hydrogenase
  A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen . Hydrogenases play a vital role in anaerobic metabolism....
  
  , the respiratory chain and the F1F0-ATPase
  F-ATPase
  F-ATPase, also known as F-Type ATPase , is an ATPase found in bacterial plasma membranes, in mitochondrial inner membranes, and in chloroplast thylakoid membranes...
  
  . This keeps this subsystem simple and clearly separated from the anabolic subsystems that starts with the Calvin cycle
  Calvin cycle
  The Calvin cycle or Calvin–Benson-Bassham cycle or reductive pentose phosphate cycle or C3 cycle or CBB cycle is a series of biochemical redox reactions that take place in the stroma of chloroplasts in photosynthetic organisms...
  
   for CO₂-fixation.
• It is able to degrade xenobiotics even in the presence of high heavy metal concentrations.
• 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
  Plasmid
  In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...
  
   pMOL28 and pMOL30 on the bacterial chromosome(s).

Also it plays a vital role, together with the species Delftia acidovorans

Delftia acidovorans

Delftia acidivorans is a Gram-negative bacterium known for its ability, together with another bacterium species, Cupriavidus metallidurans, to produce gold nuggets. Layers of these bacteria dissolve gold into nanoparticles. These nanoparticles are able to move through rocks and soil and can be...

, in the formation of gold nugget

Gold nugget

A gold nugget is a naturally occurring piece of native gold. Watercourses often concentrate and grow the nuggets. Nuggets are recovered by placer mining, but they are also found in residual deposits where the gold-bearing veins or lodes are weathered...

s, by precipitating metallic gold from a solution of gold (III) tetrachloride, a compound highly toxic to most other microorganisms.

External links

• Article at Live Science