Project description:This SuperSeries is composed of the following subset Series: GSE14239: MESSAGE 2 space experiment with Rhodospirillum rubrum S1H GSE14241: BASE-A space experiment with Rhodospirillum rubrum S1H Refer to individual Series
Project description:R. rubrum S1H inoculated on solid minimal media was sent to the ISS in September 2006 (BASE-A experiment). After 10 days flight, R. rubrum cultures returned back to Earth. These cultures were then subjected to both transcriptomic and proteomic analysis and compared with the corresponding ground control. Whole-genome oligonucleotide microarray and high throughput proteomics, which offer the possibility to survey respectively the global transcriptional and translational response of an organism, were used to test the effect of space flight. Moreover, in an effort to identify a specific stress response of R. rubrum to space flight, ground simulation of space ionizing radiation and space gravity were performed under identical culture setup and growth conditions encountered during the actual space journey. This study is unique in combining the results from an actual space experiment with the corresponding space ionizing radiation and modeled microgravity ground simulations, which lead to a more solid dissection of the different factors contribution acting in space flight conditions.
Project description:R. rubrum S1H inoculated on solid agar rich media was sent to the ISS in October 2003 (MESSAGE-part 2 experiment). After 10 days flight, R. rubrum cultures returned back to Earth. These cultures were then subjected to both transcriptomic and proteomic analysis and compared with the corresponding ground control. Whole-genome oligonucleotide microarray and high throughput proteomics, which offer the possibility to survey respectively the global transcriptional and translational response of an organism, were used to test the effect of space flight. Moreover, in an effort to identify a specific stress response of R. rubrum to space flight, ground simulation of space ionizing radiation and space gravity were performed under identical culture setup and growth conditions encountered during the actual space journey. This study is unique in combining the results from an actual space experiment with the corresponding space ionizing radiation and modeled microgravity ground simulations, which lead to a more solid dissection of the different factors contribution acting in space flight conditions.
Project description:R. rubrum S1H inoculated on solid minimal media was sent to the ISS in September 2006 (BASE-A experiment). After 10 days flight, R. rubrum cultures returned back to Earth. These cultures were then subjected to both transcriptomic and proteomic analysis and compared with the corresponding ground control. Whole-genome oligonucleotide microarray and high throughput proteomics, which offer the possibility to survey respectively the global transcriptional and translational response of an organism, were used to test the effect of space flight. Moreover, in an effort to identify a specific stress response of R. rubrum to space flight, ground simulation of space ionizing radiation and space gravity were performed under identical culture setup and growth conditions encountered during the actual space journey. This study is unique in combining the results from an actual space experiment with the corresponding space ionizing radiation and modeled microgravity ground simulations, which lead to a more solid dissection of the different factors contribution acting in space flight conditions. Total RNA was extracted from R. rubrum S1H grown after 10 days in space flight or after 10 days in simulated ionizing radiation or simulated microgravity. Each microarray slide contained 3 technical repeats.
Project description:R. rubrum S1H inoculated on solid agar rich media was sent to the ISS in October 2003 (MESSAGE-part 2 experiment). After 10 days flight, R. rubrum cultures returned back to Earth. These cultures were then subjected to both transcriptomic and proteomic analysis and compared with the corresponding ground control. Whole-genome oligonucleotide microarray and high throughput proteomics, which offer the possibility to survey respectively the global transcriptional and translational response of an organism, were used to test the effect of space flight. Moreover, in an effort to identify a specific stress response of R. rubrum to space flight, ground simulation of space ionizing radiation and space gravity were performed under identical culture setup and growth conditions encountered during the actual space journey. This study is unique in combining the results from an actual space experiment with the corresponding space ionizing radiation and modeled microgravity ground simulations, which lead to a more solid dissection of the different factors contribution acting in space flight conditions. Total RNA was extracted from R. rubrum S1H grown after 10 days in space flight or after 10 days in simulated ionizing radiation or simulated microgravity. Each microarray slide contained 3 technical repeats.
Project description:In the framework of the Micro-Ecological Life Support System Alternative (MELiSSA) project, a pilot study was performed to identify the effects of triclosan on the MELiSSA carbon-mineralizing microorganism Rhodospirillum rubrum S1H. Triclosan is a biocide that is commonly found in human excrement and is considered an emerging pollutant in wastewater and the environment. Chronic exposure to MELiSSA-relevant concentrations (> or =25 microg liter(-1)) of triclosan resulted in a significant extension of the lag phase of this organism but hardly affected the growth rate. Analytical determinations gave no indication of triclosan biodegradation during the growth experiment, and flow cytometric viability analyses revealed that triclosan is bacteriostatic and only slightly toxic to R. rubrum S1H. Using microarray analyses, the genetic mechanisms supporting the reversibility of triclosan-induced inhibition were scrutinized. An extremely triclosan-responsive cluster of four small adjacent genes was identified, for which there was up to 34-fold induction with 25 microg liter(-1) triclosan. These four genes, for which the designation microf (micropollutant-upregulated factor) is proposed, appear to be unique to R. rubrum and are shown here for the first time to be involved in the response to stress. Moreover, numerous other systems that are associated with the proton motive force were shown to be responsive to triclosan, but they were never as highly upregulated as the microf genes. In response to triclosan, R. rubrum S1H induced transcription of the phage shock protein operon (pspABC), numerous efflux systems, cell envelope consolidation mechanisms, the oxidative stress response, beta-oxidation, and carbonic anhydrase, while there was downregulation of bacterial conjugation and carboxysome synthesis genes. The microf genes and three efflux-related genes showed the most potential to be low-dose biomarkers.
Project description:In the present study, the susceptibility of the purple pigmented photosynthetic alphaproteobacterium Rhodospirillum rubrum S1H to gamma irradiation was investigated and its molecular response was characterised by means of gene expression analysis. R. rubrum S1H appears to be about 4 times more sensitive than the model strain Escherichia coli MG1655 to cobalt-60 gamma irradiation. Whole genome response of R. rubrum to 25 Gy revealed the common expression of SOS response related genes in both rich and minimal media. Quantitative expression of the lexA gene was followed after various recovery time following gamma irradiation and showed differential gene expression pattern between minimal and rich medium. This work paves the way for forthcoming molecular studies on the effect of ionizing radiation on R. rubrum S1H and the other MELiSSA strains. Keywords: Rhodospirillum rubrum; ionizing radiation tolerance; microarray; quantitative PCR.
Project description:In the frame of the European MELiSSA project, which aims to develop a closed biological life support system for forthcoming long term space exploration missions, the study of the alpha-proteobacterium Rhodospirillum rubrum S1H cultivated in space related environmental conditions has started. In the present work, the bacterium was grown using two different microgravity simulators, namely the Rotating Wall Vessel (RWV) and the Random Positioning Machine (RPM) and its response was evaluated at both the transcriptomic and proteomic levels using respectively a dedicated whole-genome microarray and high-througput proteomics. At the transcriptomic level, 13 genes were found significantly induced in the RWV samples and all 13 were included in the more pronounced response of 235 induced genes of R. rubrum S1H to the RPM cultivation. On the other hand, at the proteomic level, a few common proteins were found to be differentially expressed in RWV and RPM while the RWV appeared to induce a higher number of significantly regulated proteins. However, the transcriptomic and the proteomic approaches appeared to be complementary pointing out the likely interrelation between quorum sensing, cell pigmentation and cell aggregation in R. rubrum S1H. Future studies will aim to characterize this unknown quorum sensing regulon.
Project description:BACKGROUND:The great metabolic versatility of the purple non-sulfur bacteria is of particular interest in green technology. Rhodospirillum rubrum S1H is an ?-proteobacterium that is capable of photoheterotrophic assimilation of volatile fatty acids (VFAs). Butyrate is one of the most abundant VFAs produced during fermentative biodegradation of crude organic wastes in various applications. While there is a growing understanding of the photoassimilation of acetate, another abundantly produced VFA, the mechanisms involved in the photoheterotrophic metabolism of butyrate remain poorly studied. RESULTS:In this work, we used proteomic and functional genomic analyses to determine potential metabolic pathways involved in the photoassimilation of butyrate. We propose that a fraction of butyrate is converted to acetyl-CoA, a reaction shared with polyhydroxybutyrate metabolism, while the other fraction supplies the ethylmalonyl-CoA (EMC) pathway used as an anaplerotic pathway to replenish the TCA cycle. Surprisingly, we also highlighted a potential assimilation pathway, through isoleucine synthesis and degradation, allowing the conversion of acetyl-CoA to propionyl-CoA. We tentatively named this pathway the methylbutanoyl-CoA pathway (MBC). An increase in isoleucine abundance was observed during the early growth phase under butyrate condition. Nevertheless, while the EMC and MBC pathways appeared to be concomitantly used, a genome-wide mutant fitness assay highlighted the EMC pathway as the only pathway strictly required for the assimilation of butyrate. CONCLUSION:Photoheterotrophic growth of Rs. rubrum with butyrate as sole carbon source requires a functional EMC pathway. In addition, a new assimilation pathway involving isoleucine synthesis and degradation, named the methylbutanoyl-CoA (MBC) pathway, could also be involved in the assimilation of this volatile fatty acid by Rs. rubrum.
Project description:In the present study, the susceptibility of the purple pigmented photosynthetic alphaproteobacterium Rhodospirillum rubrum S1H to gamma irradiation was investigated and its molecular response was characterised by means of gene expression analysis. R. rubrum S1H appears to be about 4 times more sensitive than the model strain Escherichia coli MG1655 to cobalt-60 gamma irradiation. Whole genome response of R. rubrum to 25 Gy revealed the common expression of SOS response related genes in both rich and minimal media. Quantitative expression of the lexA gene was followed after various recovery time following gamma irradiation and showed differential gene expression pattern between minimal and rich medium. This work paves the way for forthcoming molecular studies on the effect of ionizing radiation on R. rubrum S1H and the other MELiSSA strains. Keywords: Rhodospirillum rubrum; ionizing radiation tolerance; microarray; quantitative PCR. Two-condition experiments. Comparing samples after exposure to gamma (Co-60) irradiation with a non-irradiated sample. At least biological duplicates. Each array contains 3 technical replicates.