Project description:Legumes interact with nodulating bacteria that convert atmospheric nitrogen into ammonia for plant use. This nitrogen fixation takes place within root nodules that form after infection of root hairs by compatible rhizobia. Using cDNA microarrays, we monitored gene expression in soybean (Glycine max) inoculated with the nodulating bacterium Bradyrhizobium japonicum 4, 8, and 16 days after inoculation (dai), time points that coincided with nodule development and the onset of nitrogen fixation. This experiment identified several thousand genes that were differentially expressed in response to B. japonicum inoculation. Expression of 27 genes was analyzed by qRT-PCR and their expression patterns mimicked the microarray results confirming integrity of analyses. The microarray results suggest that B. japonicum reduces plant defense responses during nodule development. In addition, the data revealed a high level of regulatory complexity (transcriptional, post-transcriptional, translational, post-translational) that is likely essential for development of the symbiosis and adjustment to an altered nutritional status. Keywords = symbiosis Keywords = nodulation Keywords = rhizobium Keywords = defense Keywords = ANOVA Keywords = plant Keywords: nodulating vs not nodulating
Project description:Genome-wide transcription profiling of B. diazoefficiens (formerly B. japonicum) and a phaR mutant, both cultured under microoxic conditions (0.5% O2) in Götz minimal medium supplemented with mannitol. Keywords: microoxia, polyhydroxybutyrate, protein-DNA interaction, proteomics, Rhizobia, transcriptomics
Project description:The Bradyrhizobium japonicum NtrC regulatory protein influences gene expression in response to changes in intracellular nitrogen status. Under conditions of low nitrogen, phosphorylation of NtrC results in up-regulation of a number of genes involved in nitrogen metabolism and nitrogen acquisition. To better define the exact nature of NtrC’s influence on gene expression, a ntrC mutation was created in B. japonicum and transcriptional profiling was performed by DNA microarray analysis of both the mutant and wild type strains. Bradyrhizobium japonicum USDA 110 and a ntrC mutant in the USDA 110 background were cultured in minimal medium supplemented with either 10mM glutamate (low nitrogen) or 10mM ammonium and 10mM glutamate (high nitrogen) as nitrogen sources. Four comparisons were performed: wild type high nitrogen vs. mutant high nitrogen, wild type low nitrogen vs. wild type high nitrogen, wild type low nitrogen vs. mutant low nitrogen, and mutant low nitrogen vs. mutant high nitrogen. For each of the four comparisons, three biological replicates were prepared for each strain and dye swap replications were performed for each hybridization producing a total of six arrays per comparison and 24 arrays in total.
Project description:Legumes interact with nodulating bacteria that convert atmospheric nitrogen into ammonia for plant use. This nitrogen fixation takes place within root nodules that form after infection of root hairs by compatible rhizobia. Using cDNA microarrays, we monitored gene expression in soybean (Glycine max) inoculated with the nodulating bacterium Bradyrhizobium japonicum 4, 8, and 16 days after inoculation (dai), time points that coincided with nodule development and the onset of nitrogen fixation. This experiment identified several thousand genes that were differentially expressed in response to B. japonicum inoculation. Expression of 27 genes was analyzed by qRT-PCR and their expression patterns mimicked the microarray results confirming integrity of analyses. The microarray results suggest that B. japonicum reduces plant defense responses during nodule development. In addition, the data revealed a high level of regulatory complexity (transcriptional, post-transcriptional, translational, post-translational) that is likely essential for development of the symbiosis and adjustment to an altered nutritional status. Keywords = symbiosis Keywords = nodulation Keywords = rhizobium Keywords = defense Keywords = ANOVA Keywords = plant loop design, 7 samples, 7 comparison, 2 technical repeats including dye swaps, 4 biological repeats
Project description:Adapting to nutritional downshifts is crucial for the survival of Vibrio cholerae. CgtA, a 50S ribosome-associated essential GTPase, is a bonafide stringent response protein. CgtA, in association with SpoT, modulates the intracellular (p)ppGpp alarmone levels in a nutrient-rich environment. We studied the influence of CgtA during the growth of V. cholerae in a minimal medium in contrast to its pre-defined role in a nutrient-rich medium. Here, we show the pleiotropic effects of CgtA on growth, viability, motility, morphology, and persister phenotype of a V. cholerae strain where the full-length wildtype (Wt) cgtA was deleted. An in-frame deletion of the 52 amino acids long unstructured C-terminal domain of the CgtA GTPase defined its in vivo functionality. Proteomic analyses revealed that loss of CgtA significantly altered 311 proteins involved in diverse cellular processes. However, the CgtA C-terminus deleted strain altered 240 proteins with a major overlap with the full-length cgtA deleted condition. A sustained mRNA expression pattern of CgtA is observed in a minimal medium. Whereas, in nutrient-rich LB medium, intermittent expression of cgtA is observed with the highest expression during the late-logarithmic to early-stationary phase. We propose that minimal media-associated nutrient stress coupled to cgtA depletion aggravates the intracellular stress in V. cholerae, leading to abnormal protein synthesis, altered DNA replication, and transcriptional machinery, negatively affecting cellular energy metabolism and many vital processes. This study suggests that the nutrient-media-dependent controlled expression of CgtA is a mechanism by which V. cholerae can remodel its transcriptome and proteome. Our study reveals an alternative facet of the survival of V. cholerae during nutritional downshift and the consequences concomitantly with cgtA knockdown as evident from the complex altered regulatory network.
Project description:Salmonella enterica serovar Typhimurium (STM) is one of the major causes of gastroenteritis and is linked to the consumption of contaminated food. Thereby, STM is associated to food of animal related produce (pork, chicken, eggs) and to food of non-animal related produce (vegetables, fruits, nuts, herbs and water). A lot of studies investigated the process of infection of warm-blooded mammalian hosts by STM and the underlying complex regulatory network of virulence gene expression dependent of various environmental conditions encountered in hosts. However, less is known about the proteome and possible regulatory networks for gene expression of STM outside the preferred host. Nutritional limitations and changes in temperature are the most obvious stresses outside the native host. Thus, we analyzed the proteome profile of STM grown in rich medium (LB medium) and minimal medium (PCN medium) at temperatures ranging from 8 °C to 37 °C. LB medium mimics the nutritional rich environment inside the host, whereas minimal PCN medium represents nutritional limitations outside the host, found during growth of non-animal related produce (field conditions). Further, the used range of temperature is found inside natural hosts (37 °C), at ambient room conditions (20 °C), during agricultural growth on open field (16 °C and 12 °C) and probably during food storage (8 °C). For the investigation of implications of altered nutrient availability and changes in growth temperature on STM proteome, whole cell lysates of STM grown under various conditions were analyzed by HPLC/MS-MS and label-free quantification. With this method, we are able to decipher changes in the complete proteome of STM in comparison to standard laboratory conditions mimicking the natural host.
Project description:Effects of potato tuber and stem extracts on P atrosepticum gene expression Keywords: gene expression 3-condition experiment, minimal medium vs tuber/stem extract, 2 biological replicates per each condition and 2 technical replicates for minimal medium and tuber samples
Project description:The sumitted data compares gene expression profile of Shewnaella oneidensis MR-1 on two different sets of media conditions (nutritionally rich LB medium and Lactate minimal medium)
Project description:Expression data from B. japonicum soybean root nodules including a nodulation time-course experiment with soybean nodules harvested at 10, 13, 21 and 31 dpi and transcriptome of bacteroids formed by a mutant defective in the RNA polymerase transcription factor sigma 54. Two reference data sets were established using B. japonicum cells grown in PSY medium under either aerobic or micro-aerobic conditions. Keywords: genetic modification, time course, growth conditions