Bacteria Genomes - CHLOROBIUM CHLOROCHROMATII

Green sulfur bacteria are obligate photolithoautotrophs and obligate anaerobes that are capable of growth at light intensities that will not support the growth of any other photosynthetic organisms on Earth.

One of the outstanding features of the green sulfur bacteria is their participation in highly specialised symbiotic associations with other bacteria, the phototrophic consortia. These structural associations of green sulfur bacteria and chemotrophic bacteria occur in the pelagial of many freshwater habitats. The regular structure of phototrophic consortia is unique in the microbial world such that they can be distinguished from other cell aggregates by light microscopy. At present seven different types of phototrophic consortia are known.

Phototrophic consortia represent valuable model systems for the study of signal transduction and coevolution between different bacteria. Chlorobium chlorochromatii CaD3 (name changed from Chlorochromatium aggregatum in 2005), consists of a colorless central rod-shaped bacterium surrounded by about 20 green-pigmented epibionts (an organism attached to an external surface).

Studies of the environments in which phototrophic consortia are found suggest that the epibionts are not derived from the free-living green sulfur bacteria also present but instead represent novel phylotypes.

References:

http://genome.jgi-psf.org/finished_microbes/chlag/chlag.home.html
http://tbi.montana.edu/f04/abstract_bryan.html
http://aem.asm.org/cgi/content/abstract/71/11/7434