Microarray was used to study the gene expression of P. stutzeri A1501 under different growth conditions
Ontology highlight
ABSTRACT:
ORGANISM(S): Stutzerimonas stutzeri A1501
PROVIDER: GSE6572 | GEO | 2007/04/20
SECONDARY ACCESSION(S): PRJNA98751
REPOSITORIES: GEO
Similar Datasets
Project description:Nitrogen fixation is a highly energy-demanding process and highly regulated at multiple levels. The two major signals that regulate nitrogen fixation in most diazotrophs are oxygen and ammonia. In order to study the complex regulated mechanism and to highlight the complete nitrogen fixing system in genome level, here we present the transcriptional profiles of the nitrogen fixation genes of P.stutzeri A1501 in different growth conditions with a genome-wide DNA microarray. In this study, the three samples of "P.stutzeri A1501 treated with 0.1mM ammonia and 0.5% Oxygen tension","P.stutzeri A1501 treated with 0.1mM ammonia and 0.5% Oxygen tension-2" and "P.stutzeri A1501 treated with 0.1mM ammonia and 0.5% Oxygen tension-3" were three repeat experiments, while, the other three samples of "P.stutzeri A1501 treated with 20mM ammonia and 0.5% Oxygen tension-1", "P.stutzeri A1501 treated with 20mM ammonia and 0.5% Oxygen tension-2" and "P.stutzeri A1501 treated with 20mM ammonia and 0.5% Oxygen tension-3" were three repeat experiments. The gene expressions under these two growth phases were compared to investigate which genes' expression were effected by different ammonia concentrations. Keywords: nitrogen fixation, nitrogen repression P.stutzeri whole genome microarray, which was based on our sequenced strain A1501. The microarray used in this study featured 3988 of the 4145 ORFs identified in P.stutzeri strain A1501, because 157 ORFs were not on the microarray of the inability to amplify these products. ORFs were amplified with specific primer pairs (Invitrogen). To ensure that the elements of our array would detect specifically their corresponding genes and no others, the ORF coordinates fed into the primer program were circumscribed such that they would exclude regions of any ORF that contained significant similarity to any other ORF. Agarose gel electrophoresis was used to perform quality control on all PCR products. Oligonucleotides were removed from the PCR mix by PCR 96 cleanup plate (Millipore). DNA was resuspended in 12 μl of spotting solution containing 50% dimethyl sulfoxide. PCR products were spotted onto gamma amino propylsilan coated GAPII slides (Corning) with a OmniGrid ⢠microarrayer (GeneMachines).The negative control genes were from the type III secretion system genes of shigella flexneri 2a and the commercial Arabidopsis genes (SpotReport⢠cDNA Array Validation System, Stratagene). The positive control genes were from the 16S rRNA of P.stutzeri A1501. We used Cy3-labeled genomic DNA and Cy5 dye-labeled cDNA, for hybridization. The cDNA was synthesized by reverse transcription of 5 μg of total RNA. The labeled cDNA and genomic DNA samples were mixed and hybridized at 65â for 16 hours. Genomic DNA was used as a universal internal control for the quality of the microarray and also allowed for the comparison of results across multiple experiments. Each experiment was repeated three times from the beginning of inoculation.
2010-06-11 | E-GEOD-6572 | biostudies-arrayexpress
Project description:A whole genome DNA microarray was used to undertake a global transcriptional analysis of nitrogen fixation and ammonium repression in Pseudomonas stutzeri A1501. The aim of this study was to identify the genes that are up-regulated under nitrogen fixation conditions and rapidly down-regulated as soon as 10 min after ammonia shock. The expression changed genes may be the candidate genes for the ammonia signal transmission or be involved in the nitrogen regulatory mechanism. First, P. stutzeri A1501 was treated with 0.1 mM ammonia and 0.5% Oxygen tension until the nitrogenase activity was detectable. Then the cells were sudden shifted from the nitrogen fixation conditions to the ammonia repression conditions by addition of 20 mM ammonia for 10min. Subsequently, the bacterium was collected and began the RNA extraction process. Thus, we compare the expression profilings in these two conditions in order to identify the candidate genes.
2010-05-14 | E-GEOD-14775 | biostudies-arrayexpress
Project description:A whole genome DNA microarray was used to undertake a global transcriptional analysis of nitrogen fixation and ammonium repression in Pseudomonas stutzeri A1501. The aim of this study was to identify the genes that are up-regulated under nitrogen fixation conditions and rapidly down-regulated as soon as 10 min after ammonia shock. The expression changed genes may be the candidate genes for the ammonia signal transmission or be involved in the nitrogen regulatory mechanism.
2010-02-10 | GSE14775 | GEO
Project description:Rhizobium etli is a bacteria that fix nitrogen in symbiotic activity with Phaseolus vulgaris, the common bean plant. In order to accomplish this nitrogen reduction a especial environment is induced in nodules such that gene expression of bacteroid suffer a significant change with respect to its wild type life style. With the purpose to identify genetic alterations between these physiological states, replicates of microarray data were accomplished in similar conditions between bacteria cultivated in free-life (succinate-ammonia) and those carrying on nitrogen fixation inside nodule. Three independent biological materials with one dyeswap were performed.
2014-02-03 | E-GEOD-21638 | biostudies-arrayexpress
Project description:Nitrogen fixation is an important metabolic process carried out by microorganisms, which converts molecular nitrogen into inorganic nitrogenous compounds such as ammonia (NH3). These nitrogenous compounds are crucial for biogeochemical cycles and for the synthesis of essential biomolecules, i.e. nucleic acids, amino acids and proteins. Azotobacter vinelandii is a bacterial non-photosynthetic model organism to study aerobic nitrogen fixation (diazotrophy) and hydrogen production. Moreover, the diazotroph can produce biopolymers like alginate and polyhydroxybutyrate (PHB) that have important industrial applications. However, many metabolic processes such as partitioning of carbon and nitrogen metabolism in A. vinelandii remain unknown to date.
Genome-scale metabolic models (M-models) represent reliable tools to unravel and optimize metabolic functions at genome-scale. M-models are mathematical representations that contain information about genes, reactions, metabolites and their associations. M-models can simulate optimal reaction fluxes under a wide variety of conditions using experimentally determined constraints. Here we report on the development of a M-model of the wild type bacterium A. vinelandii DJ (iDT1278) which consists of 2,003 metabolites, 2,469 reactions, and 1,278 genes. We validated the model using high-throughput phenotypic and physiological data, testing 180 carbon sources and 95 nitrogen sources. iDT1278 was able to achieve an accuracy of 89% and 91% for growth with carbon sources and nitrogen source, respectively. This comprehensive M-model will help to comprehend metabolic processes associated with nitrogen fixation, ammonium assimilation, and production of organic nitrogen in an environmentally important microorganism.
2023-03-10 | MODEL2204190001 | BioModels
Project description:Rhizobium etli is a bacteria that fix nitrogen in symbiotic activity with Phaseolus vulgaris, the common bean plant. In order to accomplish this nitrogen reduction a especial environment is induced in nodules such that gene expression of bacteroid suffer a significant change with respect to its wild type life style. With the purpose to identify genetic alterations between these physiological states, replicates of microarray data were accomplished in similar conditions between bacteria cultivated in free-life (succinate-ammonia) and those carrying on nitrogen fixation inside nodule.
2014-02-03 | GSE21638 | GEO
Project description:Rhizobium etli is a bacteria that fix nitrogen in symbiotic activity with Phaseolus vulgaris, the common bean plant. In order to accomplish this nitrogen reduction a especial environment is induced in nodules such that gene expression of bacteroid suffer a significant change with respect to its wild type life style. With the purpose to identify genetic alterations between these physiological states, replicates of microarray data were accomplished in similar conditions between bacteria cultivated in free-life (succinate-ammonia) and those carrying on nitrogen fixation inside nodule.
2014-02-03 | GSE21638 | GEO
Project description:Nitrogenase is the key enzyme involved in nitrogen fixation and uses low potential electrons delivered by ferredoxin or flavodoxin to reduce dinitrogen gas (N2) to produce ammonia and hydrogen. Although the phototrophic alphaproteobacterium Rhodopseudomonas palustris encodes many proteins that can reduce ferredoxin, the electron bifurcating FixABCX complex is the only one shown to support nitrogen fixation. To gain insight into why R. palustris is unable to use these other enzymes to reduce ferredoxin in the absence of FixABCX, we isolated a suppressor of R. palustris DfixC that allowed this strain to grow under nitrogen-fixing conditions. We found two mutations were necessary and sufficient to restore growth under nitrogen-fixing conditions in the absence of a functional FixABCX. One mutation was in the primary ferredoxin involved in nitrogen fixation, fer1, and the other mutation was in rpa0678, a homolog of NAD+-dependent ferredoxin:NADPH oxidoreductase, which carries out flavin-based electron bifurcation to generate reduced Fd. We present evidence that Rpa0678 plays a role in electron transfer to benzoyl-CoA reductase, the key enzyme involved in anaerobic aromatic compound degradation. Together these findings indicate that the electron transfer pathway for anaerobic aromatic compound degradation was re-purposed to support nitrogen fixation in the suppressor strain.
2022-07-19 | GSE208087 | GEO
Project description:Biological nitrogen fixation, the microbial reduction of atmospheric nitrogen to bioavailable ammonia, represents both a major limitation on biological productivity and a highly desirable engineering target for synthetic biology. However, the engineering of nitrogen fixation requires an integrated understanding of how the gene regulatory dynamics of host diazotrophs respond across sequence-function space of its central catalytic metalloenzyme, nitrogenase. Here, we interrogate this relationship by analyzing the transcriptome of Azotobacter vinelandii engineered with a phylogenetically inferred ancestral nitrogenase protein variant. The engineered strain exhibits reduced cellular nitrogenase activity but recovers wild-type growth rates following an extended lag period. We find that expression of genes within the immediate nitrogen fixation network is resilient to the introduced nitrogenase sequence-level perturbations. Rather the sustained physiological compatibility with the ancestral nitrogenase variant is accompanied by reduced expression of genes that support trace metal and electron resource allocation to nitrogenase. Our results spotlight gene expression changes in cellular processes adjacent to nitrogen fixation as productive engineering considerations to improve compatibility between remodeled nitrogenase proteins and engineered host diazotrophs. IMPORTANCE Azotobacter vinelandii is a key model bacterium for the study of biological nitrogen fixation, an important metabolic process catalyzed by nitrogenase enzymes. Here, we demonstrate that compatibilities between engineered A. vinelandii strains and nitrogenase variants can be modulated at the regulatory level. The engineered strain studied here responds by adjusting the expression of proteins involved in cellular processes adjacent to nitrogen fixation, rather than that of nitrogenase proteins themselves. These insights can inform future strategies to transfer nitrogenase variants to non-native hosts.
2023-06-07 | GSE234075 | GEO
Project description:Resendis-Antonio2007 - Genome-scale metabolic
network of Rhizobium etli (iOR363)
This model is described in the article:
Metabolic reconstruction and
modeling of nitrogen fixation in Rhizobium etli.
Resendis-Antonio O, Reed JL,
Encarnación S, Collado-Vides J, Palsson BØ.
PLoS Comput. Biol. 2007 Oct; 3(10):
1887-1895
Abstract:
Rhizobiaceas are bacteria that fix nitrogen during symbiosis
with plants. This symbiotic relationship is crucial for the
nitrogen cycle, and understanding symbiotic mechanisms is a
scientific challenge with direct applications in agronomy and
plant development. Rhizobium etli is a bacteria which provides
legumes with ammonia (among other chemical compounds), thereby
stimulating plant growth. A genome-scale approach, integrating
the biochemical information available for R. etli, constitutes
an important step toward understanding the symbiotic
relationship and its possible improvement. In this work we
present a genome-scale metabolic reconstruction (iOR363) for R.
etli CFN42, which includes 387 metabolic and transport
reactions across 26 metabolic pathways. This model was used to
analyze the physiological capabilities of R. etli during stages
of nitrogen fixation. To study the physiological capacities in
silico, an objective function was formulated to simulate
symbiotic nitrogen fixation. Flux balance analysis (FBA) was
performed, and the predicted active metabolic pathways agreed
qualitatively with experimental observations. In addition,
predictions for the effects of gene deletions during nitrogen
fixation in Rhizobia in silico also agreed with reported
experimental data. Overall, we present some evidence supporting
that FBA of the reconstructed metabolic network for R. etli
provides results that are in agreement with physiological
observations. Thus, as for other organisms, the reconstructed
genome-scale metabolic network provides an important framework
which allows us to compare model predictions with experimental
measurements and eventually generate hypotheses on ways to
improve nitrogen fixation.
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2015-07-30 | MODEL1507180006 | BioModels