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Yin Y.-J.,State Key Laboratory of Microbial Resources | Yin Y.-J.,Environmental Microbiology and Biotechnology Research Center | Wang B.-J.,State Key Laboratory of Microbial Resources | Wang B.-J.,Environmental Microbiology and Biotechnology Research Center | And 6 more authors.
Applied Microbiology and Biotechnology | Year: 2010

Mycothiol (MSH) was reported to be the dominant low molecular weight thiol in members of the Actinobacteria. In this study, a simple, fast, and sensitive method for qualitative and quantitative determination of MSH molecules was developed based on maleylpyruvate isomerase (MPI) from Corynebacterium glutamicum. The principle of this method is that the activity of MPI from C. glutamicum was dependent on MSH molecules. It was found that this MPI activity displayed a linear response (R 2∈=∈0.9928) at MSH amounts ranging from 0.12 to 3.98 pmol in the defined assay system. This observation was applied to calculate the MSH levels, and the newly developed method was compared with thiol-specific fluorescent-labeling high-performance liquid chromatography method. Forty-eight genera of Actinobacteria were screened for MSH and 43 genera were reported for MSH occurrence, and the MSH levels in Actinobacteria were determined to be 0.01 to 9.69 μmol/g of residual dry cell weight. © 2010 Springer-Verlag.

Zhao K.-X.,State Key Laboratory of Microbial Resources | Zhao K.-X.,CAS Institute of Microbiology | Huang Y.,State Key Laboratory of Microbial Resources | Huang Y.,Hunan University | And 4 more authors.
Journal of Bacteriology | Year: 2010

We identified a new regulator, PcaO, which is involved in regulation of the protocatechuate (PCA) branch of the β-ketoadipate pathway in Corynebacterium glutamicum. PcaO is an atypical large ATP-binding LuxR family (LAL)-type regulator and does not have a Walker A motif. A mutant of C. glutamicum in which pcaO was disrupted (RES167ΔpcaΟO) was unable to grow on PCA, and growth on PCA was restored by complementation with pcaO. Both an enzymatic assay of PCA 3,4-dioxygenase activity (encoded by pcaHG) and transcriptional analysis of pcaHG by reverse transcription-PCR revealed that PcaO positively regulated pcaHG. A promoter-LacZ transcriptional fusion assay suggested that PcaO interacted with the sequence upstream of pcaHG. Electrophoretic mobility shift assay (EMSA) analysis indicated that an imperfect palindromic sequence (-78AACCCCTGACCTTCGGGGTT-59) that was located upstream of the -35 region of the pcaHG promoter was essential for PcaO regulation. DNase I footprinting showed that this imperfect palindrome was protected from DNase I digestion. Site-directed mutation and EMSA tests revealed that this palindrome sequence was essential for PcaO binding to the DNA fragment. In vitro EMSA results showed that ATP weakened the binding between PcaO and its target sequence but ADP strengthened this binding, while the effect of protocatechuate on PcaO binding was dependent on the protocatechuate concentration. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Wang F.-X.,CAS Institute of Microbiology | Wang F.-X.,State Key Laboratory of Plant Genomics | Ma Y.-P.,CAS Institute of Microbiology | Ma Y.-P.,State Key Laboratory of Plant Genomics | And 11 more authors.
Proteomics | Year: 2011

Verticillium wilt of cotton is a vascular disease mainly caused by the soil-born filamentous fungus Verticillium dahliae. To study the mechanisms associated with defense responses in wilt-resistant sea-island cotton (Gossypium barbadense) upon V. dahliae infection, a comparative proteomic analysis between infected and mock-inoculated roots of G. barbadense var. Hai 7124 (a cultivar showing resistance against V. dahliae) was performed by 2-DE combined with local EST database-assisted PMF and MS/MS analysis. A total of 51 upregulated and 17 downregulated proteins were identified, and these proteins are mainly involved in defense and stress responses, primary and secondary metabolisms, lipid transport, and cytoskeleton organization. Three novel clues regarding wilt resistance of G. barbadense are gained from this study. First, ethylene signaling was significantly activated in the cotton roots attacked by V. dahliae as shown by the elevated expression of ethylene biosynthesis and signaling components. Second, the Bet v 1 family proteins may play an important role in the defense reaction against Verticillium wilt. Third, wilt resistance may implicate the redirection of carbohydrate flux from glycolysis to pentose phosphate pathway (PPP). To our knowledge, this study is the first root proteomic analysis on cotton wilt resistance and provides important insights for establishing strategies to control this disease. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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