page_title: Cupriavidus metallidurans
hierarchical_section_title: Cupriavidus metallidurans
caption_attribution_description: English: Bacteria play an important role in the formation of gold nuggets in Australia according to recent research. The research was carried out by the Cooperative Research Centre for Landscape Environments and Mineral Exploration (CRC LEME) and led by CSIRO researcher, Dr Frank Reith. His study of gold grains, from the Tomakin Park and Hit or Miss gold mines in southern New South Wales and northern Queensland respectively, led to a series of discoveries which showed that specific bacteria present on these gold grains precipitate gold from solution. Applying molecular biology techniques, Dr Reith discovered a living biofilm on the surface of gold grains collected. DNA profiling of this biofilm identified 30 bacterial species with populations unique to the gold grains when compared to the surrounding soils. One species was identified on all of the DNA-positive gold grains from both locations. DNA sequence analysis of this bacterium identified it as Ralstonia metallidurans.
context_page_description: Cupriavidus metallidurans strain CH34 is a non-spore-forming, Gram-negative bacterium 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 has been fully sequenced
  It is not pathogenic, therefore, models of the cell can also be tested in artificial environments similar to its natural habitats.
  It is related to the plant pathogen Ralstonia solanacearum.
  It is of ecological importance since related bacteria are predominant in mesophilic heavy metal-contaminated environments.
  It is of industrial importance and used for heavy metal remediation and sensing.
  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. The energy-providing subsystem of the cell under these conditions is composed only of the hydrogenase, the respiratory chain, and the F1F0-ATPase.
context_section_description: Cupriavidus metallidurans strain CH34 (renamed from Ralstonia metallidurans and previously known as Ralstonia eutropha and Alcaligenes eutrophus) is a non-spore-forming, Gram-negative bacterium 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 has been fully sequenced (preliminary, annotated sequence data were obtained from the DOE Joint Genome Institute)
  It is not pathogenic, therefore, models of the cell can also be tested in artificial environments similar to its natural habitats.
  It is related to the plant pathogen Ralstonia solanacearum.
  It is of ecological importance since related bacteria are predominant in mesophilic heavy metal-contaminated environments.
  It is of industrial importance and used for heavy metal remediation and sensing.
  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. The energy-providing subsystem of the cell under these conditions is composed only of the hydrogenase, 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.
  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 pMOL28 and pMOL30 on the bacterial chromosome(s).
   
  Also it plays a vital role, together with the species Delftia acidovorans, in the formation of gold nuggets, by precipitating metallic gold from a solution of gold(III) chloride, a compound highly toxic to most other microorganisms.
caption: A scanning electron microscope image of a gold nugget, revealing bacterioform (bacteria-shaped) structures
exif: {"Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop 7.0", "Image DateTime": "2007:02:07 12:10:16", "Image ExifOffset": "156", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "294", "Thumbnail JPEGInterchangeFormatLength": "7049", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "1024", "EXIF ExifImageLength": "768"}