Electron-transport-driven sodium extrusion during methanogenesis from formaldehyde and molecular hydrogen by Methanosarcina barkeri.
Methanogenesis from formaldehyde or formaldehyde + H2, as carried out by Methanosarcina barkeri, was strictly dependent on sodium ions whereas methane formation from methanol + H2 or methanol + formaldehyde was Na+-independent. This indicates that the reduction of formaldehyde to the formal redox level of methanol exhibits a Na+ requirement. During methanogenesis from formaldehyde, a delta pNa in the range of -62 mV to -80 mV was generated by means of a primary, electron-transport-driven sodium pump. This could be concluded from the following results obtained on cell suspensions of M. barkeri. 1. The addition of proton conductors or inhibitors of the Na+/H+ antiporter had no effect on sodium extrusion. 2. During methanogenesis from formaldehyde + H2 a delta psi of -60 mV to -70 mV was generated even in the presence of proton conductors. 3. ATPase inhibitors, applied in the presence of proton conductors, had no effect on primary sodium extrusion or generation of a delta psi. Evidence for a Na+-translocating ATPase could not be obtained.
Müller
V
V
Institut für Mikrobiologie der Georg-August-Universität, Göttingen, Federal Republic of Germany.
Winner
C
C
Gottschalk
G
G
D000255:Adenosine Triphosphate / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D004579:Electron Transport / Q000187:drug effects*; D019605:Euryarchaeota / Q000378:metabolism*; D005557:Formaldehyde / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D008094:Lithium / Q000494:pharmacology; D008697:Methane / Q000096:biosynthesis*; D000432:Methanol / Q000378:metabolism; D010084:Oxidation-Reduction; D011522:Protons; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000378:metabolism
D011522:Protons; D015222:Sodium Channels; D005557:Formaldehyde; D006859:Hydrogen; D000255:Adenosine Triphosphate; D008094:Lithium; D012964:Sodium; D008697:Methane; D000432:Methanol