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K Fiebig

Publications and source records attributed to K Fiebig.

3 recordsLinked to original sources
PubMed1991

Immunocytochemical localization of the coenzyme F420-reducing hydrogenase in Methanosarcina barkeri Fusaro.

The cytological localization of the 8-hydroxy-5-deazaflavin (coenzyme F420)-reducing hydrogenase of Methanosarcina barkeri Fusaro was determined by immunoelectron microscopy, using a specific polyclonal rabbit antiserum raised against the homogeneous deazaflavin-dependent enzyme. In Western blot (immunoblot) experiments this antiserum reacted specifically with the native coenzyme F420-reducing hydrogenase, but did not cross-react with the coenzyme F420-nonreducing hydrogenase activity also detectable in crude extracts prepared from methanol-grown Methanosarcina cells. Immunogold labelling of ultrathin sections of anaerobically fixed methanol-grown cells from the exponential growth phase revealed that the coenzyme F420-reducing hydrogenase was predominantly located in the vicinity of the cytoplasmic membrane. From this result we concluded that the deazaflavin-dependent hydrogenase is associated with the cytoplasmic membrane in intact cells of M. barkeri during growth on methanol as the sole methanogenic substrate, and a possible role of this enzyme in the generation of the electrochemical proton gradient is discussed.

Blotting, Western↗
PubMed1979

Utilization of trimethylamine and other N-methyl compounds for growth and methane formation by Methanosarcina barkeri.

A number of N-methyl compounds, including several methylamines, creatine, sarcosine, choline, and betaine, were readily fermented by enrichment cultures yielding methane as a major product. Methylamine, dimethylamine, trimethylamine, and ethyldimethylamine were fermented by pure cultures of Methanosarcina barkeri; except for ethyldimethylamine, these amines are considered important substrates of this methanogenic microorganism. Creatine, sarcosine, choline, and betaine were fermented to methane only by mixed cultures. During growth of M. barkeri on methyl-, dimethyl-, or trimethylamine, methanol was not excreted into the medium. The fermentation of trimethylamine gave rise to an intermediary accumulation of methyl- and dimethylamine in the medium. An accumulation of methylamine during the fermentation of dimethylamine was not observed. Methane and ammonia were produced from the three methylamines by M. barkeri in amounts expected on the basis of the appropriate fermentation equations. The growth yield was 5.8 mg of cells (dry weight) per mmol of methane and was not dependent on the kind of methyl compound used as substrate.

Euryarchaeota↗