Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Global responses of Aliivibrio salmonicida to hydrogen peroxide

ABSTRACT: Aliivibrio salmonicida causes âcold-water vibriosisâ (or âHitra diseaseâ) in fish, including marine-reared Atlantic salmon. During development of the disease the bacterium will encounter macrophages with antibacterial activities such as production of damaging reactive oxygen species (ROS). To defend itself the bacterium will presumably start producing detoxifying enzymes, reducing agents, and proteins involved in DNA and protein repair systems. Even though responses to oxidative stress are well studied for a few model bacteria, little work has been done in general to explain how important groups of pathogens, like members of the Vibrionaceae family, can survive at high levels of ROS. We have used bioinformatic tools and an âomics approach to study how A. salmonicida responds to hydrogen peroxide (H2O2). First, we used the recently published genome sequence to predict potential binding sites for OxyR (H2O2 response regulator). The computer-based search identified OxyR sites associated with 20 single genes and 8 operons, and these predictions were compared to experimental data from Northern blot analysis, microarray analysis and 2D gel electrophoresis. In general, OxyR binding site predictions and experimental results are in agreement. Up- and down-regulated genes are distributed among all functional gene categories, but a striking number of â¥2 fold up-regulated genes encode proteins involved in detoxification or DNA protection and repair, are part of reduction systems, or are involved in carbon metabolism and regeneration of NADH/NADPH. Our predictions and âomics data corroborates well with findings from other model bacteria, but also suggest species-specific gene regulation. Two-condition experiment, cells grown in LB medium (control samples) vs. cells grown under oxidative stress (H2O2) (stimulated samples). Samples collected from three different timepoints (15, 30 and 60 min). Technical replicates for each timepoint: 3 control, 3 stimulated, independently grown and harvested. One replicate per array.

ORGANISM(S): Aliivibrio salmonicida LFI1238

SUBMITTER: Peik Haugen

PROVIDER: E-GEOD-20082 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Similar Datasets

Project description:Background: Minimal change nephrotic syndrome (MCNS) is considered to be associated with T cell dysfunction, via unknown mechanisms. Experimental observations suggest that some humoral factors alter the permeability of glomerular filtration barrier. However, the nature of such factors remains still uncertain. Methods: Using cDNA microarrays, we performed gene expression profiling of peripheral blood mononuclear cells (PBMC) from three patients with MCNS during nephrosis and remission phases. To confirm the cDNA microarray results, we performed quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses in nephrosis and remission samples from 20 MCNS patients and six patients with nephrotic syndrome due to membranous nephropathy. Results: Out of 24,446 genes screened, 33 genes were up-regulated (at least 1.5-fold) in PBMC from these MCNS patients during the nephrosis phase. Up-regulated genes mainly encoded proteins involved in signal transduction and cytokine response. For further examination, we selected two genes encoding provable secretary proteins, chemokine (C-C) ligand 13 (also known as monocyte chemotactic protein-4) (CCL13) and a novel galectin-related protein (HSPC159). The results of RT-PCR showed that expressions of CCL13 and HSPC159 mRNA in nephrosis PBMC samples are higher than those in remission PBMC samples from all 20 MCNS patients examined. On the other hand, these mRNA expression patterns were variable among six patients with membranous nephropathy. Conclusions: We conclude that CCL13 and HSPC159 mRNA expressions in PBMC is up-regulated in MCNS patients during the nephrosis phase. These expression changes in PBMC might be involved in the pathophysiologic processes of MCNS. Using cDNA microarrays, we performed gene expression profiling of peripheral blood mononuclear cells (PBMC) from three patients with MCNS during nephrosis and remission phases. To confirm the cDNA microarray results, we performed quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses in nephrosis and remission samples from 20 MCNS patients and six patients with nephrotic syndrome due to membranous nephropathy.

Project description:Aeromonas salmonicida is a fish pathogen that causes furunculosis. Virulent strains of this bacterium are able to infect salmonid macrophages and survive within them, although mechanisms favouring intracellular survival are not completely understood. It is known that A. salmonicida cultured in vivo in the peritoneal cavity of the host undergoes changes in gene expression and surface architecture compared with cultures grown in vitro in broth. Therefore, in this study, the macrophage responses to A. salmonicida grown in vivo and in vitro were compared. Enriched macrophages isolated from head kidney of Atlantic salmon (Salmo salar) were infected in vitro in 96-well microtitre dishes and changes in gene expression during the infection process were monitored using a custom Atlantic salmon cDNA microarray. A. salmonicida cultures grown in tryptic soy broth and in peritoneal implants were used to infect the macrophages. The macrophages were harvested at 0.5, 1.0 and 2.0 h after addition of the bacteria to the medium. Significant changes in gene expression were evident by microarray analysis at 2.0 h post-infection in macrophages infected with broth-grown and implant-grown bacteria; however, qPCR analysis revealed earlier up-regulation of JunB and TNF-alpha in macrophages exposed to the implant-grown bacteria. Up-regulation of those genes and others is consistent with the effects of extracellular products of aeromonad bacteria on macrophages and also suggests initiation of the innate immune response. Keywords: time course Enriched macrophages from 24 responder fish that showed positive respiratory burst in response to phorbol myristate acetate were plated in individual wells of 96-well flat-bottom polystyrene tissue culture plates. A. salmonicida were added to the macrophages, and incubated for 0.5, 1.0 or 2.0 h. Control wells received 10 ul of HBSS. Three replicate infections were performed for each type of bacteria. Hybridizations were carried out in duplicate, reversing the fluors for each sample on the second chip.

Project description:Oxidative stress caused by exposure to reactive oxygen species (ROS), is a major challenge for aerobic and especially anaerobic organisms. Bacteria coordinate the response to oxidative stress through the LysR-type transcriptional regulator (LTTR) OxyR. Extensive studies have focused on the classical Escherichia coli system to shed light on the mode of action of defensive weapons against oxidative stress. The underlying mechanism is mediated via the formation of redox-dependent disulfide bond between two conserved cysteines of OxyR, thus activating transcription of members of the OxyR regulon. However, only fragmentary information on the regulation and function of OxyR has been gleaned through genetic and biochemical analyses in the important opportunistic pathogen P. aeruginosa. In this report, we used a comprehensive transcriptional profiling analysis to delineate the OxyR regulon under three conditions (KingM-bM-^@M-^Ys A medium [Pseudomonas medium or PM], Luria Broth (LB), and LB when oxyR is overexpressed), to investigate its roles in different cellular aspects that are independent of the classical oxidative stress response. Interestingly, when grown in LB, OxyR was found to regulating many genes involved in the process of inter-cellular communication known as quorum sensing (QS). In contrast, when grown in PM, OxyR regulate the expression of a newly identified CSS (cell-surface signaling) system in an OxyR-dependent fashion. In addition, the results from oxyR overexpression further confirmed that OxyR was linked to regulation of QS and Type 3 Secretion (T3SS) in addition to the regulation of antioxidative genes. Taken together, our results show that, apart from its dominant role in defense against oxidative stress in P. aeruginosa, OxyR acts as a global regulator that provides a link between the regulation of oxidative stress response, QS and virulence. 15 samples, representing 5 different biological conditions, including 3 biological replicates for each condition

Dataset Information

Global responses of Aliivibrio salmonicida to hydrogen peroxide

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure