Insights into the Oxidative Stress Response of Salmonella enterica serovar Enteritidis Revealed by the Next Generation Sequencing Approach

Abstract

As a facultative intracellular pathogen, Salmonella Enteritidis must develop an effective oxidative stress response to survive exposure to reactive oxygen species within the host. To study this defense mechanism, we carried out a series of oxidative stress assays in parallel with a comparative transcriptome analyses using a next generation sequencing approach. It was shown that the expression of 45% of the genome was significantly altered upon exposure to H2O2. Quantitatively the most significant (≥100 fold) gene expression alterations were observed among genes encoding the sulfur utilization factor of Fe-S cluster formation and iron homeostasis. Our data point out the multifaceted nature of the oxidative stress response. It includes not only numerous mechanisms of DNA and protein repair and redox homeostasis, but also the key genes associated with osmotic stress, multidrug efflux, stringent stress, decrease influx of small molecules, manganese and phosphate starvation stress responses. Importantly, this study revealed that oxidatively stressed S. Enteritidis cells simultaneously repressed key motility encoding genes and induced a wide range of adhesin- and salmonellae-essential virulence-encoding genes, that are critical for the biofilm formation and intracellular survival, respectively. This finding indicates a potential intrinsic link between oxidative stress and pathogenicity in non-typhoidal Salmonella that needs to be empirically evaluated.

Polyamine-mediated mechanisms contribute to oxidative stress tolerance in Pseudomonas syringae

“…This shows that Pst DC3000 is able to deploy detoxifying mechanisms to avoid the negative effects provoked by H 2 O 2 . In fact, it shares a similar tolerance to H 2 O 2 as E. coli and P. aeruginosa 46,47 , which can withstand relatively higher concentrations of this compound in comparison to other bacterial species such as Salmonella enterica 48 and P. putida 49 .…”

“…In this trend, our previous co-expression analyses on several P. syringae strains demonstrated a negative correlation between polyamine biosynthetic genes and catalases 18 . Besides, it was demonstrated that speE is downregulated in P. syringae B728A and P. aeruginosa PAO1, as well as in non-related species such as E. coli and Salmonella enterica in response to H 2 O 2 48,[56][57][58] . This observation implies the existence of a wide distributed regulatory mechanisms linking Spd synthesis reduction and catalase induction.…”

Functional characterization ofSalmonellaTyphimurium encoded YciF, a domain of unknown function (DUF892) family protein, and its role in protection during bile and oxidative stress

“…Typhimurium challenged with H2O2 stress shows significant induction of iron acquisition proteins (47,48). This could be as several proteins required to mitigate oxidative stress and associated DNA damage such as SodB and DNA glycosylase MutY require iron as cofactor (49)(50)(51)(52).…”

Novel Insight into the Effects of CpxR on Salmonella enteritidis Cells during the Chlorhexidine Treatment and Non-Stressful Growing Conditions

“…Moreover, major porin, OmpC, and two additional porins, OmpN and Tsx, showed decreased abundance in the cpxR background, clearly indicating that deletion of the cpxR gene imposes a stressful condition for the mutant cell. It is well documented that the decrease of porin abundance in a prokaryotic cell is an adaptive response of these organisms to exposure to a wide spectrum of antimicrobials [23,[28][29][30][31] and reactive oxygen species (ROS) [32]. Guest et al [11] demonstrated that the Cpx response affects the respiratory complexes NADH dehydrogenase I and cytochrome bo 3 .…”

“…Our data indicated that the ∆cpxR mutant is probably exposed to endogenous ROS. Not only a wide spectrum of DNA repair proteins, both envelope, and cytosol chaperones and proteases were induced, but also powerful antioxidants, including thioredoxin, glutaredoxin 1, glutaredoxin 3, and disulphide reductase, hallmarks of the oxidative stress response [32][33][34][35], showed increased abundance in the cpxR background. Taken together, decreased abundance of porins and increased abundance of antioxidants, DNA repair systems, envelope, and cytosol chaperones, and proteases, provide multiple pieces of evidence that the ∆cpxR mutant is under stress and probably exposed to an increased level of endogenous ROS.…”