Methanomicrococcus blatticola gen. nov., sp. nov., a methanol- and methylamine-reducing methanogen from the hindgut of the cockroach Periplaneta americana.

Abstract

A small irregular coccoid methanogenic bacterium (PA T ) was isolated from the hindgut of the cockroach Periplaneta americana. Fluorescence microscopy and transmission electron microscopy of the hindgut of P. americana suggest that the organism occurs abundantly in the microbiota attached to the hindgut wall. The strain produces methane by the reduction of methanol and methylated amines with molecular hydrogen. Acetate, coenzyme M, yeast extract, tryptic soy broth and vitamins are required for growth. The cells lack a rigid cell wall and lyse immediately in buffers of low ionic strength. Maximum rate of growth (specific growth rate, 022 h V1 ) occurs in a rich medium at 39 SC, at a pH range of 72-77 and at a salt concentration below 100 mM NaCl. Sequence analysis of the small-subunit rDNA indicates that strain PA T is related to the family Methanosarcinaceae but does not belong to any previously described genus. Therefore, it is proposed that strain PA T be classified in a new genus, related to the Methanosarcinaceae, as Methanomicrococcus blatticola (type strain PA T l DSM 13328 T ).

Progress in the development of vaccines against rumen methanogens

“…but are generally not a major group (Janssen and Kirs, 2008). Members of this genus also appear to convert hydrogen plus methyl compounds to methane (Sprenger et al, 2000).…”

“…but are generally not a major group (Janssen and Kirs, 2008). Members of this genus also appear to convert hydrogen plus methyl compounds to methane (Sprenger et al, 2000).The little that is known about members of Methanoplasmatales indicates that they too are methylotrophic methanogens, also metabolising hydrogen plus methyl compounds to methane in the same stoichiometry as Methanosphaera (Paul et al, 2012; J. Jeyanathan, R. Ronimus and P. H. Janssen, unpublished data). Their abundance is also likely to be limited by methyl compound availability.…”

Cross-Epithelial Hydrogen Transfer from the Midgut Compartment Drives Methanogenesis in the Hindgut of Cockroaches

“…Ethane (1 ml) was added as an internal standard (11). At regular intervals, gas samples (200 l) were taken using hypodermic needles and 1-ml syringes and analyzed for methane and hydrogen by gas chromatography (21,22). As a rule, gases were measured at 3 h and 17 to 22 h after the start of the incubation.…”

“…Gut segments were incubated in 2 ml of HEPES buffer (50 mM HEPES, 50 mM NaCl, 5 mM Na 2 HPO 4 , 1.5 mM KH 2 PO 4 [pH 7.0]) in 10-ml vials (21). Since pilot experiments had shown that under these conditions hydrogen production was linear for up to 29 h and the production of methane from endogenous substrates was linear for up to 48 h, gas production rates were analyzed using the same protocol as for living cockroaches.…”

“…A. de Gouw, and C. Warneke, unpublished results). It remains to be shown that methanol is transported between the gut compartments, but there is evidence that Methanomicrococcus blatticola, an obligately methanol-reducing, methanogenic bacterium, is a major methanogenic organism in the hindgut of the cockroach Periplaneta americana (21). While methanol should be able to pass through the epithelial barrier easily, formate and other charged metabolites would require specific transport systems.…”