Linked Life Data

2168161

Source:http://linkedlifedata.com/resource/pubmed/id/2168161

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-10-3
pubmed:abstractText
The application of recent developments of EPR oximetry to photosynthetic systems is described and used to study rapid processes in isolated thylakoid membranes from spinach and in intact photoautotrophic soybean cells. Using the peak heights of 15N perdeuterated Tempone and two microwave power levels oxygen evolution and consumption were measured. The method measured time-resolved oxygen concentration changes in the micromolar range. Oxygen evolution was linearly proportionate to the chlorophyl concentration of thylakoid membrane over the range studied (0-2 mg/ml). Oxygen evolution associated with single turnover light pulses was consistent with the four state model. The time (t1/2) to reach equilibrium of oxygen concentrations after a single turnover pulse was 0.4-0.5 ms, indicating that the evolution of oxygen coupled to the S4-S0 transition may be shorter than reported previously. The time for equilibrium of oxygen after single turnover pulses in soybean cells was relatively long (400 ms), which suggests that there are significant barriers to the free diffusion of oxygen in this system. The method also was used to study oxygen consumption by the electron transport chain of photosystem I and photosystem II. We conclude that EPR oximetry can provide quantitative and time-resolved data on oxygen concentrations with a sensitivity that is useful for studies of such systems.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:volume
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
312-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Measurement of time-resolved oxygen concentration changes in photosynthetic systems by nitroxide-based EPR oximetry.
pubmed:affiliation
Department of Plant Physiology and Biochemistry, Jagiellonian University, Krakow, Poland.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't