Abstract
Singlet oxygen (1O2) is a stress factor and signal in the facultative phototrophic bacterium Rhodobacter sphaeroides. In vivo protein labeling with L-[35S]-methionine and analysis by two-dimensional gel electrophoresis revealed that the synthesis of 61 proteins was changed in response to 1O2. After 1O2 treatment, protein synthesis patterns were distinct from those after H2O2 treatment but similar to those after high light exposure. This indicates regulatory mechanisms selective for different reactive oxygen species (ROS) and a response to light partly mediated by 1O2. Analysis of mutant strains support that the response to 1O2 is regulated mainly by rpoE (sigma E), but also a modulation of the sigma E dependent response by other factors and the existence of sigma E independent responses. The involvement of the RNA chaperon Hfq in the 1O2 response implies a role of small regulatory RNAs.
MeSH terms
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Bacterial Proteins / analysis
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Catalase / metabolism
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Cations, Divalent / metabolism
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Electrophoresis, Gel, Two-Dimensional
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Gene Expression Regulation, Bacterial
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Host Factor 1 Protein / genetics
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Hydrogen Peroxide / pharmacology
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Light
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Mutation
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Protein Biosynthesis / drug effects*
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Proteome / analysis
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Proteome / genetics
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Proteome / metabolism*
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RNA, Messenger / metabolism
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Reactive Oxygen Species / pharmacokinetics
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Rhodobacter sphaeroides / drug effects*
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Rhodobacter sphaeroides / genetics
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Rhodobacter sphaeroides / metabolism
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Sigma Factor / metabolism
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Singlet Oxygen / pharmacology*
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Transcription Factors / metabolism
Substances
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Bacterial Proteins
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Cations, Divalent
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Host Factor 1 Protein
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Proteome
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RNA, Messenger
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Reactive Oxygen Species
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Sigma Factor
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Transcription Factors
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sporulation-specific sigma factors
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Singlet Oxygen
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Hydrogen Peroxide
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hydroperoxidase II
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Catalase