The membrane potential of Methanobacterium thermoautotrophicum under different external conditions
Jazyk angličtina Země Spojené státy americké Médium print
Typ dokumentu srovnávací studie, časopisecké články, práce podpořená grantem
PubMed
11271816
DOI
10.1007/bf02817407
Knihovny.cz E-zdroje
- MeSH
- adenosintrifosfatasy antagonisté a inhibitory MeSH
- inhibitory enzymů farmakologie MeSH
- ionty MeSH
- koncentrace vodíkových iontů MeSH
- membránové potenciály MeSH
- Methanobacterium chemie růst a vývoj metabolismus MeSH
- oniové sloučeniny MeSH
- organofosforové sloučeniny MeSH
- protony MeSH
- salicylanilidy farmakologie MeSH
- sodík MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- 3,3',4',5-tetrachlorosalicylanilide MeSH Prohlížeč
- adenosintrifosfatasy MeSH
- inhibitory enzymů MeSH
- ionty MeSH
- oniové sloučeniny MeSH
- organofosforové sloučeniny MeSH
- protony MeSH
- salicylanilidy MeSH
- sodík MeSH
- tetraphenylphosphonium MeSH Prohlížeč
The membrane potential (delta psi) of whole cells of Methanobacterium thermoautotrophicum strain delta H was estimated under different external conditions using a TPP(+)-sensitive electrode. The results show that the delta psi values of M. thermoautotrophicum at alkaline pHout (8.5) are comparable with delta psi values under slightly acidic conditions (pH 6.8; 230 and 205 mV, respectively). On the other hand, the size of colonies on Petri dishes was remarkably smaller at pH 8.5 than at 6.8. The delta psi was insensitive to relevant ATPase inhibitors. At pH 6.8, the protonophore 3,3',4',5-tetrachlorosalicylanilide (TCS) strongly inhibited delta psi formation and ATP synthesis driven by methanogenic electron transport. On the other hand, at pH 8.5 the CH4 formation and ATP synthesis were insensitive to TCS and a protonophore-resistant delta psi of approximately 150 mV was determined. The finding of a protonophore-resistant delta psi at pH 8.5 indicates that at alkaline pHout these cells can switch from H(+)-energetics to Na(+)-energetics, when the delta [symbol: see text] H+ becomes limited. The results strongly support the hypothesis that at alkaline pHout Na+ ions might fully substitute for H+ in these cells as the coupling ions.
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