The second group comprising genera from the Gamma and Epsilon Proteobacteria classes are microaerophiles, which are not able to completely oxidize organic substrates to CO2; they include Wolinella, Campylobacter, Shewanella, Sulfurospirillum, and Geospirillum bamesi. Sulfate-reducing archaea is also quite phylogenetically diverse including but not limited to the following orders: Thermococcales, Thermoproteales, Pyrodictales, Sulfolobales, Pyrodictales, and Sulfolobales. Desulfuromonas acetoxidans was the first SRB isolated from anaerobic sulfide containing marine mud sediments. Archaea Archaeoglobus, Thermocladium and Caldivirga are found in hydrothermal vents, oil deposits, and hot springs.
One of the oldest forms of bacteria and archaea that convert hydrogen (H2) and sulfate (SO2) into hydrogen sulfide (H2S). Sulfate-reducing bacteria (SRB) colonize the guts of ∼50% of humans, are very diverse and include Proteobacteria - such as aerotolerant Desulfovibrio inhabiting human gut. These lactate- and hydrogen-utilizing bacteria are the principal SRB (60-80%) in studies of colonic sulfur metabolism. Desulfovibrio strain NY682, Desulfovibrio piger and Desulfovibrio fairfieldensis have been isolated from blood, brain abscess, periodontal pockets, appendix, liver, colon and bowel and are characterized by strong sulfurous odor in the environment. Other sulfate-reducing Proteobacteria found in natural environments include anaerobes Desulfomicrobium (including periodontal bacteria Desulfomicrobium orale sp. nov.), hydrogen-utilizing Desulfobulbus (present in aquatic sediments and human gut), acetate-utilizing Desulfobacter, acetone-utilizing Desulfococcus, Desulfosarcina, Desulfobacterium, Desulfonema, acetate- and butyrate-utilizing Desulfotomaculum, and Thermodesulfobacterium; also Desulfuromonas, Desulfurella, Geobacter, and Pelobacter. Interesting to note that 25% of humans do not show sulfate-reducing even though they have Desulfobulbus and other above mentioned bacteria in the gut.
The second group comprising genera from the Gamma and Epsilon Proteobacteria classes are microaerophiles, which are not able to completely oxidize organic substrates to CO2; they include Wolinella, Campylobacter, Shewanella, Sulfurospirillum, and Geospirillum bamesi. Sulfate-reducing archaea is also quite phylogenetically diverse including but not limited to the following orders: Thermococcales, Thermoproteales, Pyrodictales, Sulfolobales, Pyrodictales, and Sulfolobales. Desulfuromonas acetoxidans was the first SRB isolated from anaerobic sulfide containing marine mud sediments. Archaea Archaeoglobus, Thermocladium and Caldivirga are found in hydrothermal vents, oil deposits, and hot springs.
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