Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

FixK, a universal regulator of microaerobic growth, controls photosynthesis in Rhodopseudomonas palustris

ABSTRACT: Facultative phototrophic bacteria are excellent models for analyzing the coordination of major metabolic traits including oxidative phosphorylation, photophosphorylation, carbon dioxide fixation and nitrogen fixation. In Rhodobacter sphaeroides and R. capsulatus, a two-component system called RegBA (PrrBA) controls these functions and it has been thought that this redox sensing regulatory system was essential for coordinating electron flow and could not be easily replaced in facultative phototrophs. Here we show that this is not the case and that the oxygen-sensing FixlJ-K system, initially described in rhizobia, controls microaerobic respiration, photophosphorylation and several other metabolic traits in Rhodopseudomonas palustris. A R. palustris fixK mutant grew normally aerobically but was impaired in microaerobic growth. It was also severely impaired in photosynthetic growth and has very little bacteriochlorophyll. Transcriptome analyses indicated that FixK positively regulates heme and bacteriochlorophyll biosynthesis, cbb3 oxidase and NADH dehydrogenase genes, as well as genes for hydrogen uptake, iron oxidation, and aromatic compound degradation. Electrophoretic mobility shift assays showed that FixK binds directly to the promoters of a bacteriochlorophyll biosynthesis operon, a bacteriophytochrome-histidine kinase gene and the fnr-type regulatory gene, aadR. AadR is likely responsible for mediating some indirect effects of FixK on expression of anaerobic genes. These results underscore that physiologically similar bacteria can use very different regulatory strategies to control common major metabolisms. Comparison of transcription profiles of Rhodopseudomonas palustris wild type and fixK mutant grown microaerobically.

ORGANISM(S): Rhodopseudomonas palustris

SUBMITTER: Yasuhiro Oda

PROVIDER: E-GEOD-6742 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Publications

FixK, a global regulator of microaerobic growth, controls photosynthesis in Rhodopseudomonas palustris.

Rey Federico E FE Harwood Caroline S CS

Molecular microbiology 20100201 4

Purple non-sulphur phototrophic bacteria (PNSB) are excellent models for analysing the co-ordination of major metabolisms, including oxidative phosphorylation, photophosphorylation, carbon dioxide fixation and nitrogen fixation. In species studied to date, a two-component system called RegBA controls these functions and it has been thought that this redox sensing regulatory system is essential for co-ordinating electron flow and cannot be easily replaced. Here we show that this is not the case f ...[more]

PMID: 20487293

Similar Datasets

Project description:Clostridium difficile is a gram-positive, spore-forming enteric anaerobe which can infect humans and a wide variety of animal species. Recently, the incidence and severity of human C. difficile infection has markedly increased. In this study, we evaluated the genomic content of 73 C. difficile strains isolated from humans, horses, cattle, and pigs by comparative genomic hybridization with microarrays containing coding sequences from C. difficile strains 630 and QCD-32g58. The sequenced genome of C. difficile strain 630 was used as a reference to define a candidate core genome of C. difficile and to explore correlations between host origins and genetic diversity. Approximately 16% of the genes in strain 630 were highly conserved among all strains, representing the core complement of functional genes defining C. difficile. Absent or divergent genes in the tested strains were distributed across the entire C. difficile 630 genome and across all the predicted functional categories. Interestingly, certain genes were conserved among strains from a specific host species, but divergent in isolates with other host origins. This information provides insight into the genomic changes which might contribute to host adaptation. Due to a high degree of divergence among C. difficile strains, a core gene list from this study offers the first step toward the construction of diagnostic arrays for C. difficile.investigated by determining changes in transcript profiles when aerobic steady-state cultures were depleted of air. Dye-swap experiments with genomic DNA of tested and reference strains 8383cy3.gpr- Cy3 – test, Cy5 – reference 8384cy3.gpr- Cy3 – test, Cy5 – reference 8384cy5.gpr- Cy3 – reference, Cy5 – test 8385cy3.gpr- Cy3 – test, Cy5 – reference 8385cy5.gpr- Cy3 – reference, Cy5 – test 8386cy3.gpr- Cy3 – test, Cy5 – reference 8525cy3.gpr- Cy3 – test, Cy5 – reference 8525cy5.gpr- Cy3 – reference, Cy5 – test 8527cy5.gpr- Cy3 – reference, Cy5 – test 8529cy5.gpr- Cy3 – reference, Cy5 – test 8531cy3.gpr- Cy3 – test, Cy5 – reference 8531cy5.gpr- Cy3 – reference, Cy5 – test 8533cy3.gpr- Cy3 – test, Cy5 – reference 8533cy5.gpr- Cy3 – reference, Cy5 – test 8596cy3.gpr- Cy3 – test, Cy5 – reference 8596cy5.gpr- Cy3 – reference, Cy5 – test 8694cy3.gpr- Cy3 – test, Cy5 – reference 8694cy5.gpr- Cy3 – reference, Cy5 – test 2 GPR files per Sample record except for 4 Sample records (GSM480414, GSM480417, GSM480419, and GSM480420) which have 1 GPR file each 4 GPR file for those Sample records are lost

Project description:Berberine is a natural isoquinoline alkaloid found in Chinese medicinal herbs which is active against a variety of microbial infections. To examine the potential effects of berberine on Shigella flexneri, a whole-genome DNA microarray was constructed and transcriptome analysis of the cellular responses of S.flexneri when exposed to Berberine Chloride (BC) was performed. When cultures were grown to early exponential growth phase, drug was added. Meanwhile, DMSO solution without BC was added to control cultures to the same final concentration. At 30 min after treatment, samples were collected and washed twice with phosphate buffered saline at 25°C for subsequent RNA isolation. To prepare biological replicates for RNA isolation, each experiment was independently performed three times. After drug treatment, total RNA was extracted using SV RNA Isolation System (Promega). Reverse transcription of 20 ug RNA from each sample was performed with Superscript II system (Invitrogen) to prepare cDNA. According to the manufacturer's instructions, the cDNA was labeled with incorporation of fluorescent dyes (Amersham). Cy3-dCTP monofunctional dye was selected for control cDNA samples and Cy5-dCTP was used for drug-treated samples. Each pair of labeled cDNA was mixed and dried by vacuum centrifugation. The pairs of the labeled cDNA samples were hybridized to the DNA microarrays following the protocol available at http://www.ifr.ac.uk/safety/microarrays/. The slides were scanned by using a GenePix 4100A scanner. Fluorescent spots and local background intensities were quantified using GenePix Pro 6.0 software (Axon). Signal intensities were corrected by subtracting the local background value. The data set was filtered so that spots flagged as "not found," "bad," and "empty" were excluded from further analysis. Moreover, spots either with signal-to-noise ratio below the detection limit of 3 or containing less than 55% of pixels two standard deviations above background in both channels were discarded from the data set. Lowess normalization was performed with the fluorescent signal ratios (Cy5/Cy3) using MIDAS software (http://www.tigr.org/software/tm4) with a 0.33 smooth parameter.

Project description:The genome sequence is the “blue-print of life”, but proteomics is required to relate this blue-print of life to the actual physiology of living cells. Because of their low complexity – only about 2.000 proteins make a Staphylococcus aureus cell viable – bacteria are excellent model systems to identify the entire protein assembly of a living organism. Many of the studies on physiological proteomics of bacteria, however, still rely on 2D gel-based technologies that visualize only a minor part of the proteome. In this study it will be shown that the majority of proteins expressed in the Gram-positive human pathogen S. aureus can be identified and even quantified by a combination of gel-based and gel-free approaches, the latter having undergone formidable improvements over the last 10 years. S. aureus has been the model of choice for our proteomic studies, because it combines high pathogenicity with increasing antibiotic resistance, which calls for new leads in the development of anti-staphylococcal therapy. On the way towards the entire proteome of S. aureus, we analysed four subproteomic fractions: cytosolic proteins, membrane-bound proteins, cell-surface associated and extracellular proteins, the two latter fractions containing most of the virulence factors. To obtain quantitative results, we compared growing cells and non-growing/stationary phase cells using the 15N metabolic labelling approach. With almost 2.000 proteins, 80 % of the expressed proteome was identified and even quantified in growing and non-growing cells. A comprehensive inventory of the entire protein assembly during the two physiologically distinct states is presented, which integrates data ranging from gene expression to subcellular localization. Three major protein classes were distinguished: (i) Proteins induced in the stationary phase only (ii) Vegetative proteins, no longer synthesized but stable in the stationary phase (iii) Vegetative proteins, no longer required in non-growing cells and finally degraded. This quantitative proteomics approach for growing/non-growing cells, which represents a proof-of-principle for whole-cell physiological proteomics, can now be extended to address particular infection-relevant physiological states. Importantly, the present model study represents the highest coverage of a bacterial proteome so far (except low complexity bacteria). It thus paves the way towards a new understanding of cell physiology and pathophysiology of S. aureus and related pathogenic bacteria, opening a new era in infection-related research on this crucial pathogen. For the DNA-microarray experiment RNA was extracted from two independently grown cultures. One was grown in 14N labelled BioExpress medium and the other in 15N labelled BioExpress medium. Samples of exponentially growing cells (OD600=0.5) and of cell at 5h after entry into stationary phase were harvested from every culture. Equal amounts of all four RNAs were pooled and the pool was used as common reference (Cy3-labeld) for the four sample RNAs (Cy3). Thus, in total four hybridizations, one for each sample versus the common reference, were performed.

Dataset Information

FixK, a universal regulator of microaerobic growth, controls photosynthesis in Rhodopseudomonas palustris

Publications

FixK, a global regulator of microaerobic growth, controls photosynthesis in Rhodopseudomonas palustris.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets