Linked Life Data

11694397

Source:http://linkedlifedata.com/resource/pubmed/id/11694397

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-11-5
pubmed:abstractText
In an attempt to uncover electric field interactions between PS I and PS II during their functioning, fluorescence induction curves were measured on hydroxylamine-treated thylakoids of Chenopodium album under conditions ensuring low and high levels of photogenerated membrane potentials. In parallel experiments with Peperomia metallica chloroplasts, the photocurrents were measured with patch-clamp electrodes and served as indicator of electrogenic activity of thylakoid membranes in continuous light. Inhibition of linear electron flow at PS II donor side by hydroxylamine (0.1 mM) eliminated a slow rise of chlorophyll fluorescence to a peak level and suppressed photoelectrogenesis. Activation of PS I-dependent electron transport using cofactors of either cyclic (phenazine methosulfate) or noncyclic electron transport (reduced TMPD or DCPIP in combination with methyl viologen) restored photoelectrogenesis in hydroxylamine-treated chloroplasts and led to reappearance of slow components in the fluorescence induction curve. Exposure of thylakoids to valinomycin reduced the peak fluorescence in the presence of KCl but not in the absence of KCl. Combined application of valinomycin and nigericin in the presence of KCl exerted stronger suppression of fluorescence than valinomycin alone but was ineffective in the absence of KCl. In samples treated with hydroxylamine and PS I cofactors (DCPIP/ascorbate and methyl viologen), preillumination with a single-turnover flash or a multiturnover pulse shifted the induction curves of both membrane potential and chlorophyll fluorescence to shorter times, which confirms the supposed influence of PS I-generated electrical field on PS II fluorescence. A model is presented that describes modulating effect of the membrane potential on chlorophyll fluorescence and roughly simulates the fluorescence induction curves measured at low and high membrane potentials.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1567-5394
pubmed:author
pubmed:issnType
Print
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
157-68
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Modulation of photosystem II chlorophyll fluorescence by electrogenic events generated by photosystem I.
pubmed:affiliation
Biophysics Department, Faculty of Biology, Moscow State University, Moscow 119899, Russia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't