Rhodobacter sphaeroides WT 2.4.1 under singlet oxygen stress
Ontology highlight
ABSTRACT:
ORGANISM(S): Rhodobacter sphaeroides 2.4.1
SUBMITTER: Gabriele Klug
PROVIDER: E-GEOD-42244 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:To learn more about the function of SurS, we constructed an over-expression strain. For this purpose, the surS gene together with its native RpoE promoter was cloned into the middle-copy plasmid pBBR1 and expressed in the R. sphaeroides wild-type 2.4.1 background. The corresponding strain consequently exhibits a singlet oxygen-induced SurS over-expression compared to an empty vector control. Total RNA from the over-expression (pSurS) and from the empty vector control (pBBR) strain was extracted after 7 min of singlet oxygen stress and used for microarray analysis to investigate SurS-induced changes on transcriptome level. RNA samples collected after 7 min of singlet oxygen stress were analyzed by two-color microarrays. Each microarray contains a pool of three independent biological replicates for each sample.
2014-07-04 | E-GEOD-59046 | biostudies-arrayexpress
Project description:High intracellular levels of unbound iron can contribute to the production of reactive oxygen species (ROS) in the Fenton reaction, while depletion of iron limits the availability of iron containing proteins, some of which have important functions in the oxidative stress defense. Vice versa increased ROS levels lead to damage of proteins with iron sulfur centers. Thus organisms have to coordinate and balance their responses to oxidative stress and iron availability. Our knowledge on the molecular mechanisms underlying the coregulation of these responses is still limited. To discriminate between a direct cellular response to iron limitation and indirect responses, which are the consequence of increased levels of ROS, we compared the response of the alpha proteobacterium Rhodobacter sphaeroides to iron limitation in presence or absence of oxygen. While some genes respond to iron limitation exclusively or much stronger in presence of oxygen, other genes show much stronger response in anaerobic conditions. Remarkably few genes show even opposite response to iron depletion in presence or absence of iron. RNA samples collected from anaerobically grown cultures in presence or absence of iron were analyzed by two-color microarrays
2013-05-23 | E-GEOD-47182 | biostudies-arrayexpress
Project description:Exposure to oxygen and light generates photooxidative stress by the bacteriochlorophyll a mediated formation of singlet oxygen (1O2) in the facultative photosynthetic bacterium Rhodobacter sphaeroides. We have identified SorY as an sRNA, which is induced under several stress conditions and confers increased resistance against 1O2. SorY by direct interaction decreases the levels of takP mRNA, encoding a TRAP-T transporter. A takP mutant shows higher resistance to 1O2 than the wild type, which is no longer affected by SorY. We present a model in which SorY reduces the metabolite flux into the TCA cycle by reducing malate import through TakP. It was previously shown that oxidative stress in bacteria leads to switch from glycolysis to the pentose phosphate cycle and to reduced activity of the tricaboxylic acid cycle. As a consequence the production of the prooxidant NADH is reduced and production of the protective NADPH is enhanced. In R. sphaeroides enzymes for glycolysis, pentose phosphate pathway, EntnerM-bM-^@M-^SDoudoroff pathway and gluconeogenesis are induced in response to 1O2 by the alternative sigma factor RpoHII. The same is true for the sRNA SorY. By limiting malate import SorY thus contributes to the balance of the metabolic fluxes under photooxidative stress conditions. This assigns a so far unknown function to an sRNA in oxidative stress response. RNA samples collected from a control strain harbouring an empty vector (2.4.1pBBR) and of the SorY overexpressing strain (2.4.1pBBRSorYi) after 10 min of 1O2 stress were analyzed by two-color microarrays
2014-11-18 | E-GEOD-63328 | biostudies-arrayexpress
Project description:The facultatively photosynthetic bacterium Rhodobacter sphaeroides harbors an unusual LOV (light, oxygen, voltage) domain protein, RsLOV. While showing a characteristic photocycle, the protein misses a C - terminal output domain, similar to PpSB2 in Pseudomonas putida. Oxygen tension and light quantity are the two main responsible factors controlling the expression of photosynthesis genes in Rhodobacter sphaeroides. Two photoreceptor proteins are known to be involved in this regulation: the intensively studied AppA protein and the more recently identified cryptochrome-like protein CryB. Here we show by transcriptome and physiological studies that RsLOV is also involved in the regulation of photosynthetic gene expression. Our data further hint to a connection between RsLOV and the carbon hydrate metabolism, chemotaxis, as well as to the cellular response to photooxidative stress. RsLOV does not only affect blue light dependent gene expression but also redox-dependent regulation. This SuperSeries is composed of the following subset Series: GSE33194: R. sphaeroides ?lov vs. R. sphaeroides 2.4.1 (microarobic conditions) GSE33259: R. sphaeroides ?lov vs. R. sphaeroides 2.4.1 (blue light, semiaerobic conditions) GSE33260: R. sphaeroides ?lov vs. R. sphaeroides 2.4.1 (singlet oxygen stress, aerobic conditions)
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Project description:Iron-sulphur (Fe-S) clusters are ensembles of iron and sulphide centres. They are found in all life forms and are important components of many enzymes involved in diverse cellular processes, including respiration, DNA synthesis or gene regulation. However, the increase in oxygen after the emergence of oxygenic photosynthesis created a threat to FeM-bM-^@M-^SS proteins and, consequently, to the organisms relying on them. Therefore, bacteria have evolved mechanisms to maintain a precise intracellular iron concentration. A major role of IscR in R. sphaeroides iron dependent regulation was suggested in a bioinformatic study , which predicted a binding site in the upstream regions of several iron uptake genes. Most known IscR proteins have Fe-S clusters featuring (Cys)3(His)1 ligation. However, IscR proteins from Rhodobacteraceae harbour only one Cys residue and it was considered unlikely that they can ligate an Fe-S cluster. In this study, the role of R. sphaeroides IscR as transcriptional regulator and sensor of the Fe-S cluster status of the cell was analysed. The results provide evidence that R. sphaeroides IscR functions as transcriptional repressor of genes involved in iron metabolism by binding to the predicted DNA binding motif. Furthermore, IscR possesses a unique Fe-S cluster ligation scheme with only a single cysteine involved. RNA samples collected from a control strain (wild type 2.4.1) and of the iscR deletion strain (2.4.1M-bM-^HM-^FiscR) were analyzed by two-color microarrays
2015-02-03 | E-GEOD-65537 | biostudies-arrayexpress
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2011-10-25 | E-GEOD-33260 | biostudies-arrayexpress
Project description:Transcriptional profiling of R. sphaeroides pRPcrZ compared to control R. sphaeroides pR4352 under low oxygen conditions. In this study we compared the transcriptome of a PcrZ over-expression strain to a control strain. PcrZ is the first small non-coding RNA, which is involved in the complex regulatory network of photosynthesis gene regulation in Rhodobacter sphaeroides. It counteracts the formation of photosynthetic complexes in a redox dependent manner. Two-strain experiment at low oxygen conditions (0.5 mg/L O2)
2012-08-14 | E-GEOD-37381 | biostudies-arrayexpress
Project description:Transcriptional profiling of R. sphaeroides delta-cryB compared to control R. sphaeroides 2.4.1 under photo-oxidative stress, aerobic conditions. Two-strain experiment under 20' photo-oxidative stress (singlet oxygen generated by methylene blue under high light illumination) and aerobic (180 µM) conditions
2011-11-09 | E-GEOD-33553 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2013-05-30 | E-GEOD-47450 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE33553: R. sphaeroides delta-cryB vs. R. sphaeroides 2.4.1 photo-oxidative stress, aerobic conditions GSE33554: R. sphaeroides delta-CryB vs. R. sphaeroides 2.4.1 microarobic conditions GSE33555: R. sphaeroides delta-cryB vs. R. sphaeroides 2.4.1 under blue light, semiaerobic conditions Refer to individual Series
2011-11-09 | E-GEOD-33556 | biostudies-arrayexpress