Linked Life Data

6462175

Source:http://linkedlifedata.com/resource/pubmed/id/6462175

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1982-7-8
pubmed:abstractText
By use of 31P NMR, the transmembrane pH gradient (delta pH) and the intracellular levels of phosphorylated metabolites were measured in aerobic suspensions of wild-type Escherichia coli cells in the presence and absence of the adenosinetriphosphatase (ATPase) inhibitor dicyclohexylcarbodiimide (DCCD); the same parameters were also determined in E. coli mutants deficient in ATPase activity under both anaerobic and aerobic conditions. A method is described by which dense suspensions of E. coli cells (approximately 3 X 10(11) cells/mL) were oxygenated so that steady-state O2 levels in the suspensions were far greater than the Km for O2 consumption. Under these conditions, in wild-type MRE600 cells, the intracellular concentrations of PI, NTP, and NDP were measured to be 3.0 +/- 1.5, 8 +/- 1, and 1.2 +/- 1 mM, respectively, while the intracellular pH was approximately 7.5 over the external pH range studied (6 to approximately 7.0). Upon treatment with DCCD, the intracellular NTP level was drastically reduced and intracellular Pi concentration increased in respiring wild-type cells; in the same cells, however, DCCD did not affect the intracellular pH and the delta pH. During respiration in the presence of lactate, ATPase- cells established a delta pH but failed to synthesize any detectable levels of NTP. Conversely, ATPase- cells accumulated high levels of NTP but did not generate a delta pH during glycolysis under anaerobic conditions. These results are in complete agreement with the generally accepted chemiosmotic hypothesis. 31P NMR data on intact ATPase- NR70 cells were in agreement with the previously proposed [Rosen, B. P., Brey, R., & Hasan, S. (1978) J. Bacteriol. 134, 1030] existence of a proton leak in this strain which is sealed by DCCD or by spontaneous mutation into strain NR71. However, the NMR data also indicated that other major differences exist between NR71 and NR70 cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1068-75
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Phosphorus-31 nuclear magnetic resonance studies of bioenergetics in wild-type and adenosinetriphosphatase(1-) Escherichia coli cells.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.