Anoxygenic phototrophs are evolutionary a very old group of prokaryotes. They contain photosynthetic reaction centers composed of bacteriochlorophyll. In year 2000 it was found that these organisms are widespread component of marine microbial community. Phototrophic bacteria represent 1-10% of all bacteria in the euphotic zone of the oceans, which implies their important role in the marine carbon cycle.
The phylogenetic analyses place all the isolates within the alpha 4 and alpha 3 subclass of Proteobacteria. The functionality of the photosynthetic apparatus was proven by kinetic bacteriochlorophyll fluorescence measurements and CO2 fixation assays. However, these bacteria are not capable of truly autotrophic growth, as they require a supply of organic carbon. The presence of the photosynthetic apparatus seems to represent an ecological advantage in nutrient poor marine environments serving as an alternative source of ATP for basal metabolism (See recent review).
In Trebon, we study anoxygenic phototrophs since 2002 employing biophysical, biochemical and molecular metods. We have isolated about 30 strains from different aquatic habitats. Strain Erythrobacter sp. NAP1 was nominated for the full genome sequencing performed by J. Craig Venter Institute. Presence of phototrophic bacteria was studied in different parts of the world ocean using infrared epifluorescence microscopy and an ultra sensitive fluorometer developed in colaboration with Photon Systems Instruments Ltd., Brno.
Institute of Microbiology
Academy of Sciences of the Czech Republic