Linked Life Data

16664913

Source:http://linkedlifedata.com/resource/pubmed/id/16664913

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2010-6-29
pubmed:abstractText
The membrane potential difference, the net H(+) exchange rate, the K(+) net flux, and the K(+) ((86)Rb(+)) influx were measured in excised corn roots as functions of the K(+) concentration in the medium at various pH values, in the presence of poorly permeant anions. The roots behaved as a K(+)/H(+) exchange system. By comparing the results in normal or hypoxic conditions, or in the presence of vanadate, it was possible to distinguish the active components of membrane potential and transports from the passive ones. The magnitude of the electrogenic potential was not related to the active H(+) extrusion rate. At pH 6, the variations of the electrogenic potential resulted from variations of the stoichiometry of the active H(+)/K(+) exchange. The same relationship between this stoichiometry and the K(+) concentration was observed in conditions ensuring different membrane polarizations (pH 6, pH 4, or pH 6 with fusicoccin). Both metabolic and Mg-ATPase specific inhibitors stopped the active H(+) transport and the net K(+) influx. Nevertheless, the tracer influx in the presence of vanadate remained higher than the passive influx calculated from the permeability coefficient determined in hypoxia. It is proposed that vanadate uncouples the K(+) moiety of the H(+)/K(+) antiport and allows it to mediate isotopic exchanges.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jul
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
81
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
847-53
pubmed:dateRevised
2010-9-14
pubmed:year
1986
pubmed:articleTitle
H and k electrogenic exchanges in corn roots.
pubmed:affiliation
Biochimie et Physiologie Végétales, Institut National de la Recherche Agronomique (Centre National de la Recherche Scientifique, UA 573), Ecole Nationale Supérieure Agronomique, 34060 Montpellier Cedex, France.
pubmed:publicationType
Journal Article