title: Transcriptional Profiling of Hydrogen Production Metabolism of Rhodobacter capsulatus under Temperature Stress by Microarray Analysis.
abstract: Biohydrogen is a clean and renewable form of hydrogen, which can be produced by photosynthetic bacteria in outdoor large-scale photobioreactors using sunlight. In this study, the transcriptional response of Rhodobacter capsulatus to cold (4 °C) and heat (42 °C) stress was studied using microarrays. Bacteria were grown in 30/2 acetate/glutamate medium at 30 °C for 48 h under continuous illumination. Then, cold and heat stresses were applied for two and six hours. Growth and hydrogen production were impaired under both stress conditions. Microarray chips for R. capsulatus were custom designed by Affymetrix (GeneChip®. TR_RCH2a520699F). The numbers of significantly changed genes were 328 and 293 out of 3685 genes under cold and heat stress, respectively. Our results indicate that temperature stress greatly affects the hydrogen production metabolisms of R. capsulatus. Specifically, the expression of genes that participate in nitrogen metabolism, photosynthesis and the electron transport system were induced by cold stress, while decreased by heat stress. Heat stress also resulted in down regulation of genes related to cell envelope, transporter and binding proteins. Transcriptome analysis and physiological results were consistent with each other. The results presented here may aid clarification of the genetic mechanisms for hydrogen production in purple non-sulfur (PNS) bacteria under temperature stress.
authors.affiliation: Department of Biological Sciences, Middle East Technical University, Ankara 06800, Turkey. muazzez@metu.edu.tr.
authors.forename: Muazzez
authors.initials: M
authors.lastname: Gürgan
authors.affiliation: Department of Biological Sciences, Middle East Technical University, Ankara 06800, Turkey. niluferafsar@gmail.com.
authors.forename: Nilüfer Afşar
authors.initials: NA
authors.lastname: Erkal
authors.affiliation: Micro-Electro-Mechanical Systems, Middle East Technical University, Ankara 06800, Turkey. bebru@metu.edu.tr.
authors.forename: Ebru
authors.initials: E
authors.lastname: Özgür
authors.affiliation: Department of Biological Sciences, Middle East Technical University, Ankara 06800, Turkey. ufukg@metu.edu.tr.
authors.forename: Ufuk
authors.initials: U
authors.lastname: Gündüz
authors.affiliation: Department of Chemical Engineering, Middle East Technical University, Ankara 06800, Turkey. ieroglu@metu.edu.tr.
authors.forename: Inci
authors.initials: I
authors.lastname: Eroglu
authors.affiliation: Department of Biological Sciences, Middle East Technical University, Ankara 06800, Turkey. meraly@metu.edu.tr.
authors.forename: Meral
authors.initials: M
authors.lastname: Yücel
mesh_terms: D058639:Cold-Shock Response; D020869:Gene Expression Profiling; D018869:Heat-Shock Response; D006859:Hydrogen / Q000378:metabolism*; D016354:Rhodobacter capsulatus / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D006859:Hydrogen
keywords: Rhodobacter capsulatus; gene expression; heat and cold stress; microarray analysis