Methanogens in the Digestive Tract of Termites

摘要: Methanogenesis in the enlarged hindgut compartments of termites is a product symbiotic digestion, fueled by hydrogen and reduced one-carbon compounds formed during fermentative breakdown plant fiber humus. Methanogens are not always predominant hydrogenotrophic microorganisms, especially wood-feeding termites, but restricted to particular microhabitats within gut. The methanogens lower belong different lineages Methanobacteriales that either endosymbionts flagellate protists or colonize periphery hindgut, habitat fully anoxic. oxygen-reducing capacities few isolates so far available indicate they well adapted continuous influx oxygen across gut wall. Higher which lack flagellates, often have highly compartmented guts with dynamic physicochemical conditions, including redox pH. differences between microenvironments most pronounced soil-feeding species, where each compartment houses characteristic archaeal community, comprising Methanobacteriales, Methanosarcinales, Methanomicrobiales, novel, deep-branching lineage putative distantly related Thermoplasmatales. All clades form distinct phylogenetic clusters unique intestinal tract insects, exception several Methanobrevibacter none these archaea been isolated pure culture. high methane emissions together their enormous biomass tropics, make them significant natural source this important greenhouse gas.