Methylosinus

Abstract

Me.thyl.o.si' nus . Fr. methyle the methyl radical; sinus bend; M.L. n. Methylosinus methyl bender. Proteobacteria / Alphaproteobacteria / Rhizobiales / Methylocystaceae / Methylosinus Cells are pyriform or vibrioid in shape, 0.5–1.5 × 1.5–3.0 µm, usually arranged in rosettes of 4–6 cells. Reproduce by binary and budding division . In budding division, the bud contains a heat and desiccation‐resistant exospore , which germinates into a vegetative daughter cell; this daughter cell is motile , propelled by a tuft of 3–10 polar and/or subpolar flagella. Cells contain type II intracytoplasmic membranes that are arranged as multiple layers along the periphery of the cell wall. Strongly accumulate inclusions of poly‐β‐hydroxybutyrate. Aerobic, possessing a strictly respiratory type of metabolism with oxygen as the terminal electron acceptor . Obligately methanotrophic , utilizing only methane and methanol as sole carbon and energy sources. C 2+ and other C 1 compounds are not utilized. Fix formaldehyde for cell carbon via the serine pathway. Enzymes for the Benson–Calvin cycle pathway are absent. The tricarboxylic acid pathway is complete. Fix atmospheric nitrogen by means of an oxygen‐sensitive nitrogenase . Mesophilic. Nonhalophilic. Optimal temperature, 25–30°C; optimal pH, 6.5–7.0. Major habitats include soil, freshwater sediments and groundwater. Primary fatty acids are C 18 : 1 ω 8c and C 18: 1 ω 7c . Primary quinone is ubiquinone‐8 ( Q‐8 ). Member of the Family Methylocystaceae found in the Alphaproteobacteria . The mol % G + C of the DNA is : 62–67 ( T m ). Type species : Methylosinus trichosporium (ex Romanovskaya, Malashenko and Bogachenko 1978) Bowman, Sly, Nichols and Hayward 1993c, 751.