Heliobacterium
The heliobacteria are phototrophic, that is to say, they convert light energy into chemical energy by photosynthesis; they use a PSI type reaction center. The primary pigment involved is bacteriochlorophyll g, which is unique to the group and has a unique absorption spectrum.
Phototrophy takes place at the cell membrane, which does not form folds or compartments as it does in purple phototrophic bacteria. Even though heliobacteria are phototrophic, they can grow without light by fermentation of pyruvate.
RNA trees place the heliobacteria among the Firmicutes but they do not stain gram-positively. They have no outer membrane and like certain other firmicutes (clostridia) they form heat resistant endospores, which contain high levels of calcium and dipicolinic acid. Heliobacteria are the only firmicutes known to conduct photosynthesis.
Heliobacteria are photoheterotrophic, requiring organic carbon sources, and they are exclusively anaerobic.
RNA trees place the heliobacteria among the Firmicutes but they do not stain gram-positively. They have no outer membrane and like certain other firmicutes (clostridia) they form heat resistant endospores, which contain high levels of calcium and dipicolinic acid. Heliobacteria are the only firmicutes known to conduct photosynthesis.
Heliobacteria are photoheterotrophic, requiring organic carbon sources, and they are exclusively anaerobic.
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