Linked Life Data

4143

Source:http://linkedlifedata.com/resource/pubmed/id/4143

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1976-7-6
pubmed:abstractText
In strong illumination, 3-(3, 4-dichlorophenyl)-1,1-dimethylurea (DCMU)-poisoned chloroplasts exhibit a high yield of chlorophyll fluorescence while P-700 turnover, proton uptake, and phosphorylation are inhibited and a pH gradient is undectectable. When 10muM N-methylphenazonium methosulfate (PMS) is included, the fluorescence yield in light is substantially reduced, and when 100 muM ascorbate is also included, the yield is diminished approximately to the level in darkness. Only very slight increases in P-700 turnover and proton uptake (but no detectable pH gradient) accompany the fluorescence yield decline. When 10muM PMS and 15 mM ascorbate are added to poisoned chloroplasts (the oxygen concentration being greatly reduced), P-700 turnover, proton uptake, the pH gradient and phosphorylation all reach high levels. In this case, the yield of chlorophyll fluorescence is low and is the same in both light and dark. Further addition of an uncoupler eliminates proton uptake, the pH gradient and phosphorylation but does not significantly elevate the fluorescence yield. From these observations we suggest that, in DCMU-poisoned chloroplasts, the fluorescence quenching with PMS occurrs by a mechanism unrelated to the generation of a phosphyorylation potential. With chloroplasts unpoisoned by DCMU, PMS quenches fluorescence and considerably stimulates proton uptake, the pH gradient and phosphorylation. However, in this case, PMS serves to restore net electron transport.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
430
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
165-81
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
Evidence against proton gradient formation being the cause of chlorophyll fluorescence quenching by N-methylphenazonium methosulfate.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.