Dataset Information

Global responses of Aliivibrio salmonicida to hydrogen peroxide

ABSTRACT: Aliivibrio salmonicida causes “cold-water vibriosis” (or “Hitra disease”) 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 –omics 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 ≥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 –omics data corroborates well with findings from other model bacteria, but also suggest species-specific gene regulation.

ORGANISM(S): Aliivibrio salmonicida LFI1238 Aliivibrio salmonicida

PROVIDER: GSE20082 | GEO | 2010/03/01

SECONDARY ACCESSION(S): PRJNA124277

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description: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.

Project description:Spot 42 was discovered in Escherichia coli nearly 40 years ago as an abundant, small and unstable RNA. Its biological role remained obscure until it was shown to cause discoordinate expression of the galactose operon (gal operon). Recently Spot 42 has also been implicated in having broader roles in the central and secondary metabolism. Spot 42 is encoded by the spf gene. The gene is ubiquitous in the Vibrionaceae family of gamma-proteobacteria, which includes a number of serious pathogens of humans and animals, including the infamous Vibrio cholerae. One member of this family, Aliivibrio salmonicida, causes cold-water vibriosis in farmed Atlantic salmon. Its genome encodes Spot 42 with 84 % identity to E. coli Spot 42 (spf). We generated a A. salmonicida spf deletion mutant. We then and used microarray and Northern blot analyses to monitor global effects on the transcriptome in order to provide insights into the biological roles of Spot 42 in this bacterium. In the presence of glucose we found a surprisingly large number of ≥2× differentially expressed genes, and several major cellular processes were affected, such as carbohydrate metabolism and transport, motility and chemotaxis, iron homeostasis and quorum sensing. A gene encoding a pirin-like protein (VSAL_I1200) showed an on/off expression pattern in the presence/absence of Spot 42, which suggests that Spot 42 plays a key regulatory role in the central metabolism by regulating the switch between fermentation and respiration. Interestingly, in a global search we discovered a sRNA, named VSsrna24, which is encoded immediately downstream of spf. This new sRNA has an expression pattern opposite to that of Spot 42, and its expression is highly dependent on glucose. Our hypothesis is that this novel sRNA works in concert with Spot 42 to regulate carbohydrate metabolism and uptake. Two-condition experiment, wild type cells (control samples) vs. spf mutants grown in A. salmonicida-specific minimal media (ASMM) (stimulated samples). Samples were prepared by culturing the A. salmonicida wild type and a spf deletion mutant strains at 12 °C in ASMM without any added carbon source to OD 600nm 0.4. At this density glucose to 44.4 mM was added. Samples were collected 15 min after stimulation. Biological replicates for each sample: 3 wild type, 3 spf mutant, independently grown and harvested. One replicate per array.

Dataset Information

Global responses of Aliivibrio salmonicida to hydrogen peroxide

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets