purple bacteria


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purple bacteria

A colloquial term for the proteobacteria.

purple bacteria (Proteobacteria)

a PHYLUM (potentially of KINGDOM status) within the DOMAIN BACTERIA. see CLASSIFICATION. The purple bacteria include most of the Gram-negative bacteria (see GRAM'S STAIN), encompassing both photosynthetic and non-photosynthetic species. The photosynthetic bacteria are generally ANAEROBES (some are FACULTATIVE, others OBLIGATE). They contain BACTERIOCHLOROPHYLL and the purple PROTEIN bacteriorhodopsin. PHOTOSYNTHESIS is ANOXYGENIC. The purple sulphur photosynthetic bacteria use sulphur compounds, such as hydrogen sulphide, instead of water, and produce sulphur granules instead of OXYGEN. The purple non-sulphur photosynthetic bacteria use organic compounds such as acids. Non-photosynthetic bacteria include ENTEROBACTERIA, RHIZOBACTERIA, AGROBACTERIA, RICKETTSIA, MYXOBACTERIA and some of the SULPHATE-REDUCING AND SULPHUR-REDUCING BACTERIA.