Source:http://linkedlifedata.com/resource/pubmed/id/16593434
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| Predicate | Object |
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| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
6
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| pubmed:dateCreated |
2010-6-30
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| pubmed:abstractText |
State 1-state 2 transitions in an intact tobacco leaf were monitored by the photoacoustic method. Modulated oxygen evolution yield and its enhancement by continuous far-red light ("Emerson enhancement") were used to characterize the balance of light distribution between the two photosystems. These measurements were additionally supported by fluorimetry. Adaptation of the leaf to far-red light (lambda [unk] 700 nm), mainly absorbed in photosystem I (light 1), results in state 1, where short-wavelength light (light 2) is distributed in favor of photosystem II. This is shown by a low yield of oxygen evolution, a high extent of Emerson enhancement, a concomitantly high extent of fluorescence quenching by far-red light, and a low ratio of the 77 K emission peaks at 730 and 695 nm. The magnitudes of these parameters were reversed when the leaf was adapted to light 2 (state 2), indicating a change towards a more equal distribution of the excitation between the two photosystems. Preincubation of an intact leaf with NaF, a specific phosphatase inhibitor, stimulated the extent of adaptation to light 2, shown by all the above criteria, and completely abolished adaptation to light 1. Light 1 preillumination prior to NaF treatment resulted initially in state 1, but then a transition to state 2 was irreversibly induced by any light. The NaF effect was specific because NaCl did not affect the state 1-state 2 transitions. Leaching out the NaF restored the original physiological transitions of the leaf. NaF presumably acts here in the same way as it acts in isolated thylakoids-by blocking the dephosphorylation of membranal proteins (particularly the chlorophyll a/b-protein complex) phosphorylated by a light 2-activated kinase. Our results give direct support to the suggestion [Allen, J. F., Bennett, J., Steinback, K. E. & Arntzen, C. J. (1981) Nature (London) 291, 25-29] that it is the phosphorylation level of thylakoid proteins that controls the light distribution between the two photosystems in vivo, shown previously in isolated thylakoids.
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| pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-16661269,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-467680,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-488114,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-5370012,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-5775694,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-6245872,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-6811597,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-6846479,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-6847199,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-6933557,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-7125674,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-7213677,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593434-7397139
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Mar
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| pubmed:issn |
0027-8424
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
81
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
1614-8
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| pubmed:dateRevised |
2010-9-15
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| pubmed:year |
1984
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| pubmed:articleTitle |
Evidence that phosphorylation and dephosphorylation regulate the distribution of excitation energy between the two photosystems of photosynthesis in vivo: Photoacoustic and fluorimetric study of an intact leaf.
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| pubmed:affiliation |
Biochemistry Department, Weizmann Institute of Science, Rehovot 76100, Israel.
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| pubmed:publicationType |
Journal Article
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