ISSN:
1432-072X
Keywords:
Methanobacterium thermoautotrophicum
;
Na+ dependent methanogenesis
;
Na+/H+ antiporter
;
Monensin
;
Gramicidin
;
Uncoupler
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Methane formation from H2 and CO2 in methanogenic bacteria is a Na+-dependent process. In this communication the effects of Na+ ionophores, of uncouplers, and of Na+/H+ antiporter inhibitors on methane formation from H2 and CO2 were studied with Methanobacterium thermoautotrophicum. 1. Na+ ionophores (the Na+/H+ antiporters monensin and lasalocid and the Na+ uniporter gramicidin) stimulated methanogenesis at lwo external Na+ concentrations when the K+ concentration was high. The ionophores had no effect at high external Na+ concentrations and were inhibitory at low external K+ concentrations. 2. Uncouplers (protonophores and valinomycin plus K+) inhibited methanogenesis at low external Na+ concentration at both low and high external K+ concentrations. Inhibition by uncouplers was relieved by the addition of either Na+ or Na+ ionophores. 3. Na+/H+ antiporter inhibitors (harmaline, amiloride, and NH 4 + ) inhibited methanogenesis at low external Na+ concentration. Inhibition was relieved by the addition of either Na+ or of the Na+ ionophores. The results are discussed with respect to the role of Na transport across the cytoplasmic membrane in methanogenesis from H2 and CO2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00402348
