Linked Life Data

4004268

Source:http://linkedlifedata.com/resource/pubmed/id/4004268

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1985-7-17
pubmed:abstractText
Starved whole cells of the obligately alkalophilic Bacillus firmus RAB synthesize ATP upon addition of L-malate at pH 9.0 as expected of an aerobic organism that grows oxidatively on nonfermentable carbon sources at pH values as high as 11.0. The current study was a detailed examination of the perplexing inability of such cells to exhibit ATP synthesis in response to a valinomycin-mediated potassium diffusion potential at pH 9.0. While there were minor differences in the patterns of generation of the potential and the proton influx that accompanies its generation in the three different buffering systems employed, the magnitude of the transmembrane electro-chemical potential of protons was at least as high as pH 9.0 as at pH 7.0. Nevertheless, a diffusion potential consistently energized ATP synthesis at pH 7.0 but not at 9.0; these findings were independent of the presence or absence of Tris or of Na+. By contrast, the artificial electron donor ascorbate, in the presence of phenazine methosulfate, energized ATP synthesis by the starved whole cells at both pH values. The same phenomenon, i.e., efficacy of a respiration-derived potential but not of a diffusion potential at pH 9.0, was demonstrated in ADP + Pi-loaded membrane vesicles. On the other hand, electrogenic Na+-coupled solute transport could be energized by both ascorbate/phenazine and methosulfate and a diffusion potential in the vesicles at pH 9.0. The results are discussed in connection with models of a localized path of proton flow between proton pumps and the ATP synthase.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:volume
239
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
327-33
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Failure of an alkalophilic bacterium to synthesize ATP in response to a valinomycin-induced potassium diffusion potential at high pH.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.