Project description:This SuperSeries is composed of the following subset Series: GSE25579: Time series analysis of the transition from dark to light growth of Dinoroseobacter shibae DFL12 GSE25581: Time series analysis of the transition from light to dark growth of Dinoroseobacter shibae DFL12 Refer to individual Series
Project description:Transcriptomes of Dinoroseobacter shibae DSM16493 wild type and clpX knockout mutant were recorded under white and blue light and in dark.
Project description:Light dependent gene expression in D. shibae wildtype compared to the gene expression in the transposonmutants D. shibae Dshi_1135::Tn, D. shibae ppaA::Tn and D. shibae ppsR::Tn. Dinoroseobacter shibae DFL12T (DSM 16493T) and the transposonmutants D. shibae Dshi_1135::Tn, D. shibae ppaA::Tn and D. shibae ppsR::Tn were grown in artificial saltwater minimal medium (SWM) in baffled flasks shaking at 180 rpm and 30 °C and incubation was performed under light, dark and bluelight conditions. D. shibae wild type and mutant strain were grown under aerobic conditions up to the mid exponential growth phase (OD578 nM 0.5).
Project description:Transcriptional response of the photoheterotrophic marine bacterium D. shibea to changing light regimes. Second part of the study analysing the transition from photoheterotrophic light to heterotrophic dark growth. Bacterial aerobic anoxygenic photosynthesis (AAP) is an important mechanism of energy gain in aquatic habitats, accounting for up to 5% of the surface ocean’s photosynthetic electron transport. The dominant AAP bacteria in marine communities belong to the Roseobacter clade. For this reason we used Dinoroseobacter shibae as a model organism to study the transcriptional response of AAP bacteria to changing light regimes. We used continuous cultivation of D. shibae in a chemostat in combination with time series microarray analysis in order to identify gene regulatory patterns after a change in illumination. The change from heterotrophic growth in the dark to photoheterotrophic growth in the light was accompanied by a strong but transient activation of a broad stress response to cope with the formation of harmful singlet oxygen during photophosphorylation, an immediate downregulation of photosynthesis-related genes, fine-tuning of the expression of electron transport chain components and upregulation of the transcriptional and translational apparatus. Furthermore, our data indicate that D. shibae might use the 3-hydroxypropionate cycle for CO2 fixation. Analysis of the transcriptome dynamics after the switch from light to dark demonstrates that only few genes are directly regulated in response to light and other signals such as singlet oxygen concentration, electron flow, redox status and energy charge of the cell must be involved in the regulation of the processes accompanying AAP. Based on the transcriptome data first hypothesis about transcriptional control of AAP could be formulated. This study provides the first analysis of AAP on the level of transcriptome dynamics. Our data allow the formulation of testable hypotheses about the mechanisms involved in the regulation of this important biological process.