Chlorobium tepidum TLS
| Names | Chlorobium tepidum TLS |
|---|---|
| Accession numbers | NC_002932 |
| Background | Chlorobium tepidum is a thermophilic green sulfer bacteria originally isolated from a New Zealand hot spring. This type of bacterium has special light-harvesting complexes called chlorosomes that contain bacteriochlorophylls and carotenoids. Chlorobium grows in dense mats over hot springs as well as in other warm muds and bodies of water that contain sufficient hydrogen sulfide (used by C. tepidum as an elecron donor). C. tepidum is a valuable model for the green sulfur bacteria because it is easily cultivated and naturally transformable.The genome of C. tepidum's single circular chromosome is 2,154,946 bp and was the first sequenced in the phylum Chlorobia. Many genes were found to be highly conserved among photosynthetic species and seemed to have no clear function within C. tepidum; however, these genes are thought to play specific roles in photosynthesis or photobiology. Phylogenomic analysis and comparison showed that C. tepidum contains duplications of genes involved in biosynthetic pathways for photosynthesis and the metabolism of sulfer and nitrogen. These methods also displayed genetic similarities between C. tepidum metabolic processes and many Archaeal species (Eisen et al. 2002).Chlorobium are Gram-negative cells. Chlorobium sp. can from long chains of almost spherical cells. Some strains can form coils of C-shaped cells. Chlorobium tepidum lives by anoxygenic photosynthesis and produces elemental sulfur as a waste product. C. tepidum deposits the elemental sulfer outside its cells unlike Chromatium and Thiothrix, two other sulfer-producing bacteria. In addition, they can photooxidize hydrogen as well as other sulfur compounds like sulfide, polysulfide, and thiosulfate. They are also obligatory autotrophic.The major light-harvesting antenna organelle, which uses electromagnetic energy to power these processes, in C. tepidum is the chlorosome, which consists of highly aggregated bacteriochlorophyll c and carotenoids surrounded by a lipid-protein envelope. This ovoid structure is different from most other phototrophic organisms. (However, they are similar to a structure contained within the phylogenetically distant family Chloroflexaceae.) The chlorosomes are 70 to 180 nm long and 30 to 60 nm wide.C. tepidum is a green sulfur bacterium that generally grows in a dense mat over hot springs. They are also found in anoxic and sulfide-rich waters, mud, and sediments. They grow best at tempuratures between 40 and 50 degrees Celsius and at a pH between 6.0 and 4.5.The phototrophic bacterial composition of a bacterial mat or in any body of water is usuallly dependent on what quality and wavelength of light that the water recieves. Factors that effect this are algae that filter the light and the terrain surrounding the hot spring, mud, or body of water. Bacteria of different pigments capture different wavelengths of light; therefore, Chlorobium and other green sulfur bacteria like Chromotium, as well as other phototrophic bacteria, can be found distributed throughout their environment in a way that allows them to survive and efficiently compete with one another. In addition to the quality of light, C. tepidum and other green sulfur bacteria require sufficient amounts of hydrogen sulfide or other such electron donors for their unique photosynthetic pathways (Montesinos et al.1983). (From http://microbewiki.kenyon.edu/index.php/Chlorobium) (MicrobeWiki: Chlorobium) |
| Taxonomy | |
| Kingdom: | Bacteria |
| Phylum: | Chlorobi |
| Class: | Chlorobia |
| Order: | Chlorobiales |
| Family: | Chlorobiaceae |
| Genus: | Chlorobaculum |
| Species: | tepidum |
| Strain | TLS |
| Complete | Yes |
| Sequencing centre | (08-APR-2002) National Center for Biotechnology Information, NIH, Bethesda, MD 20894, USA (30-APR-2002) The Institute for Genomic Research, 9712 Medical Center Dr, Rockville, MD 20850, USA |
| Sequencing quality | Level 6: Finished |
| Sequencing depth | NA |
| Sequencing method | NA |
| Isolation site | New Zealand high-sulfide hot spring |
| Isolation country | New Zealand |
| Number of replicons | 1 |
| Gram staining properties | Negative |
| Shape | Bacilli |
| Mobility | No |
| Flagellar presence | No |
| Number of membranes | 2 |
| Oxygen requirements | Anaerobic |
| Optimal temperature | 48.0 |
| Temperature range | Thermophilic |
| Habitat | Specialized |
| Biotic relationship | Free living |
| Host name | NA |
| Cell arrangement | Chains, Singles |
| Sporulation | Nonsporulating |
| Metabolism | Nitrogen fixation |
| Energy source | Photolithoautotroph, Photosynthetic |
| Diseases | NA |
| Pathogenicity | No |