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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2010-6-29
pubmed:abstractText
The light- and sulfide-dependent induction process leading to photosystem I-mediated sulfide utilization by Oscillatoria limnetica, for either H(2) evolution or CO(2) photoassimilation, was studied. The identical dependence on pH of the lag length, the inhibition of leucine incorporation and final H(2)S concentration imply that the latter exerts a deleterious effect on nonadapted cells.Na-dithionite (Na(2)S(2)O(4)), Na-sulfite (Na(2)SO(3)), or ethanol cannot serve as photosynthetic electron donors. However, when these compounds were added to the sulfide-containing system, the need for induction was eliminated. At pH 6.9, in the presence of 3.5 millimolar sulfide, these substances (at concentrations of 10 millimolar, 5 millimolar, or 0.4 molar, respectively) completely abolished the delay preceding sulfide-dependent H(2) evolution. It is suggested that all three compounds expose a site capable of directly accepting sulfide electrons.Only dithionite could adapt the cells to sulfide utilization on its own. Sulfite or ethanol acted only in the presence of sulfide. It is implied that this specific activity of dithionite is related to its characteristic low redox potential.Sulfide-dependent H(2) evolution was insensitive to 3-(3,4-dichlorophenyl)-1,1-dimethylurea, but was inhibited by the plastoquinone antagonist 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, in the presence as well as in the absence of dithionite. In both cases, therefore, the plastoquinone was implied in the electron transport from sulfide.
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
72
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
825-8
pubmed:dateRevised
2010-9-14
pubmed:year
1983
pubmed:articleTitle
Na-Dithionite Promotes Photosynthetic Sulfide Utilization by the Cyanobacterium Oscillatoria limnetica.
pubmed:affiliation
Division of Microbial and Molecular Ecology, Institute of Life Sciences, The Hebrew University, Jerusalem 91904, Israel.
pubmed:publicationType
Journal Article