scholarly journals The Lactic Acid-Induced Acid Tolerance Response in Salmonella enterica Serovar Typhimurium Induces Sensitivity to Hydrogen Peroxide

2006 ◽  
Vol 72 (8) ◽  
pp. 5623-5625 ◽  
Author(s):  
E. J. Greenacre ◽  
S. Lucchini ◽  
J. C. D. Hinton ◽  
T. F. Brocklehurst
Keyword(s):  
Hydrogen Peroxide ◽  
Lactic Acid ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Acid Tolerance ◽  
Down Regulation ◽  
Acid Tolerance Response ◽  
Essential Component ◽  
Serovar Typhimurium ◽  
Tolerance Response

ABSTRACT Transcriptome analyses of Salmonella enterica serovar Typhimurium revealed that 15 genes were significantly up-regulated after 2 h of adaptation with lactic acid. cadB was the most highly up-regulated gene and was shown to be an essential component. Lactic acid-adapted cells exhibited sensitivity to hydrogen peroxide, likely due to down-regulation of the OxyR regulon.

scholarly journals Salmonella enterica Serovar Typhimurium and Listeria monocytogenes Acid Tolerance Response Induced by Organic Acids at 20°C: Optimization and Modeling

2003 ◽  
Vol 69 (7) ◽  
pp. 3945-3951 ◽  
Author(s):  
E. J. Greenacre ◽  
T. F. Brocklehurst ◽  
C. R. Waspe ◽  
D. R. Wilson ◽  
P. D. G. Wilson
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Salmonella Enterica ◽  
Acid Tolerance ◽  
Acid Tolerance Response ◽  
Serovar Typhimurium ◽  
Tolerance Response ◽  
Acid Inactivation ◽  
Log Linear

ABSTRACT An acid tolerance response (ATR) has been demonstrated in Listeria monocytogenes and Salmonella enterica serovar Typhimurium in response to low pH poised (i.e., adapted) with acetic or lactic acids at 20°C and modeled by using dynamic differential equations. The ATR was not immediate or prolonged, and optimization occurred after exposure of L. monocytogenes for 3 h at pH 5.5 poised with acetic acid and for 2 h at pH 5.5 poised with lactic acid and after exposure of S. enterica serovar Typhimurium for 2 h at pH 5.5 poised with acetic acid and for 3 h at pH 5.5 poised with lactic acid. An objective mechanistic analysis of the acid inactivation data yielded estimates of the duration of the shoulder (t s ), the log-linear decline (k max), and the magnitude of a critical component (C). The magnitude of k max gave the best agreement with estimates of conditions for optimum ATR induction made from the raw data.

scholarly journals CadC Has a Global Translational Effect during Acid Adaptation in Salmonella enterica Serovar Typhimurium

2007 ◽  
Vol 189 (6) ◽  
pp. 2417-2425 ◽  
Author(s):  
Yong Heon Lee ◽  
Bae Hoon Kim ◽  
Ji Hye Kim ◽  
Won Suck Yoon ◽  
Seong Ho Bang ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Regulatory System ◽  
Acid Tolerance ◽  
Negative Influence ◽  
Acid Adaptation ◽  
Proteomic Approach ◽  
Serovar Typhimurium ◽  
Tolerance Response ◽  
Porin Proteins

ABSTRACT In Salmonella enterica serovar Typhimurium, the membrane-localized CadC is a transcriptional activator of the cadBA operon, which contributes to the acid tolerance response. Unlike in Escherichia coli, in which transcription of cadC is constitutive, in S. enterica serovar Typhimurium cadC expression is induced by low pH and lysine. Inactivation of cadC suppresses the acid-sensitive phenotype of a cadA mutation, suggesting the existence of other CadC-dependent genes in addition to the cadBA operon. Using a proteomic approach, we identified 8 of the putative CadC-induced proteins and 15 of the putative CadC-repressed proteins. The former include porin proteins OmpC and OmpF. The latter include proteins involved in glycolysis, energy production, and stress tolerance. To better understand the altered levels of OmpC and OmpF, we compared expression of ompR in S. enterica serovar Typhimurium wild-type and cadC mutant strains and determined that CadC exerted a negative influence on ompR transcription. Taken together, our findings strongly suggest that CadC may be a global regulator involved in the OmpR regulatory system during acid adaptation.

scholarly journals Global Transcriptome and Mutagenic Analyses of the Acid Tolerance Response of Salmonella enterica Serovar Typhimurium

2015 ◽  
Vol 81 (23) ◽  
pp. 8054-8065 ◽  
Author(s):  
Daniel Ryan ◽  
Niladri Bhusan Pati ◽  
Urmesh K. Ojha ◽  
Chandrashekhar Padhi ◽  
Shilpa Ray ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Molecular Mechanisms ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Differentially Expressed ◽  
Acid Tolerance Response ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Tolerance Response

ABSTRACTSalmonella entericaserovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability ofS. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, whichS. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability ofS. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis ofS. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than −1.5-fold;P< 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute toS. Typhimurium ATR and virulence. Mutants lacking genes encoding the K+binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed variedin vitrovirulence characteristics. This study offers greater insight into the transcriptome changes ofS. Typhimurium under the ATR and provides a framework for further research on the subject.

scholarly journals Sanitation of fresh green asparagus and green onions inoculated with Salmonella

2009 ◽  
Vol 27 (No. 6) ◽  
pp. 454-462 ◽  
Author(s):  
M.A. Martínez-Téllez ◽  
F.J. Rodríguez-Leyva ◽  
I.E. Espinoza-Medina ◽  
I. Vargas-Arispuro ◽  
A.A. Gardea ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Lactic Acid ◽  
Exposure Time ◽  
Salmonella Enterica ◽  
Fresh Produce ◽  
Clean Water ◽  
Effective Agent ◽  
Serovar Typhimurium ◽  
Postharvest Handling ◽  
Green Asparagus

The absence of good agricultural and manufacturing practices in the production and postharvest handling of fresh produce, such as green asparagus or green onions increase the contamination risk by biological hazards like Salmonella. The objective of this work was to investigate the efficacy of chlorine (200 and 250 ppm), hydrogen peroxide (1.5% and 2%), and lactic acid (1.5% and 2%) sanitisers during different exposure times (40, 60, and 90 s) on the reduction of <i>Salmonella enterica</i> subspecie <i>enterica</i> serovar Typhimurium in inoculated fresh green asparagus and green onions. Washing with clean water only reduced < 1 log10 CFU/g in both vegetables. The most effective sanitiser evaluated for fresh green asparagus and green onions disinfection appeared to be 2% lactic acid reducing <i>Salmonella</i> growth close to 3 log<sub>10</sub> CFU/g. Hydrogen peroxide was the least effective agent for <i>Salmonella</i> Typhimurium reduction. No effect was observed of the exposure time of inoculated product to sanitiser up to 90 seconds. These results confirm that lactic acid could be used as an alternative for fresh green asparagus and green onions sanitation.

scholarly journals Identification of Salmonella enterica Serovar Typhimurium Genes Important for Survival in the Swine Gastric Environment

2006 ◽  
Vol 72 (4) ◽  
pp. 2829-2836 ◽  
Author(s):  
Shawn M. D. Bearson ◽  
Bradley L. Bearson ◽  
Mark A. Rasmussen
Keyword(s):  
Lactic Acid ◽  
Salmonella Enterica ◽  
Ex Vivo ◽  
Stomach Contents ◽  
Acid Tolerance ◽  
Lethal Effect ◽  
Gastric Fluid ◽  
Low Ph ◽  
Chromatography Analysis ◽  
Serovar Typhimurium

ABSTRACT Since the stomach is a first line of defense for the host against ingested microorganisms, an ex vivo swine stomach contents (SSC) assay was developed to search for genes important for Salmonella enterica serovar Typhimurium survival in the hostile gastric environment. Initial characterization of the SSC assay (pH 3.87) using previously identified, acid-sensitive serovar Typhimurium mutants revealed a 10-fold decrease in survival for a phoP mutant following 20 min of challenge and no survival for mutants of rpoS or fur. To identify additional genes, a signature-tagged mutagenesis bank was constructed and screened in the SSC assay. Nineteen mutants were identified and individually analyzed in the SSC and acid tolerance response assays; 13 mutants exhibited a 10-fold or greater sensitivity in the SSC assay compared to the wild-type strain, but only 3 mutants displayed a 10-fold or greater decrease in survival following pH 3.0 acidic challenge. Further examination determined that the lethal effects of the SSC are pH dependent but that low pH is not the sole killing mechanism(s). Gas chromatography analysis of the SSC revealed lactic acid levels of 126 mM. Upon investigating the effects of lactic acid on serovar Typhimurium survival in a synthetic gastric fluid, not only was a concentration- and time-dependent lethal effect observed, but the phoP, rpoS, fur, and pnp genes were identified as involved in protection against lactic acid exposure. These studies indicate a role in gastric survival for several serovar Typhimurium genes and imply that the stomach environment is defined by more than low pH.

Variability in the adaptive acid tolerance response phenotype of Salmonella enterica strains

2017 ◽  
Vol 62 ◽  
pp. 99-105 ◽  
Author(s):  
Alexandra Lianou ◽  
George-John E. Nychas ◽  
Konstantinos P. Koutsoumanis
Keyword(s):  
Salmonella Enterica ◽  
Acid Tolerance ◽  
Acid Tolerance Response ◽  
Tolerance Response ◽  
Response Phenotype

Lactic acid bacteria and bifidobacteria attenuate the proinflammatory response in intestinal epithelial cells induced by Salmonella enterica serovar Typhimurium

2013 ◽  
Vol 59 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Christine M. Carey ◽  
Magdalena Kostrzynska
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Salmonella Typhimurium ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Farm Animals ◽  
Bifidobacterium Adolescentis ◽  
Lactobacillus Kefir ◽  
Serovar Typhimurium ◽  
Ht 29

Inflammation is a physiological response to infections and tissue injury; however, abnormal immune responses can give rise to chronic inflammation and contribute to disease progression. Various dietary components, including probiotic lactic acid bacteria and prebiotics, have the potential to modulate intestinal inflammatory responses. One factor in particular, the chemokine interleukin-8 (IL-8, CXCL-8), is one of the major mediators of the inflammatory response. The purpose of this study was to investigate modulation of the inflammatory host response induced by Salmonella enterica serovar Typhimurium DT104 in the presence of selected probiotics and lactic acid bacteria (LAB) isolated from human sources, dairy products, and farm animals. IL-8 gene expression and protein production in HT-29 cells were evaluated by real-time PCR and ELISA, respectively. Pre-incubation of HT-29 cells with Lactobacillus kefir IM002, Bifidobacterium adolescentis FRP 61, Bifidobacterium longum FRP 68 and FRP 69, Bifidobacterium breve FRP 334, and Leuconostoc mesenteroides IM080 significantly inhibited IL-8 secretion induced by Salmonella Typhimurium DT104. Co-culture of selected probiotics and Salmonella Typhimurium DT104 reduced IL-8 production, while potential probiotics and LAB had no effect on IL-8 secretion in HT-29 cells preincubated with Salmonella Typhimurium DT104 prior to adding probiotics. Lactobacillus kefir IM002 supernatant also significantly reduced IL-8 production. In conclusion, our study suggests that probiotic bifidobacteria and LAB modulate cytokine induction and possess anti-inflammatory properties; however, the effectiveness is strain dependent.

scholarly journals A Salmonella enterica Serovar Typhimurium hemA Mutant Is Highly Susceptible to Oxidative DNA Damage

2002 ◽  
Vol 184 (14) ◽  
pp. 3774-3784 ◽  
Author(s):  
Maya Elgrably-Weiss ◽  
Sunny Park ◽  
Eliana Schlosser-Silverman ◽  
Ilan Rosenshine ◽  
James Imlay ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Salmonella Enterica ◽  
Fenton Reaction ◽  
Oxidative Dna Damage ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Intracellular Iron ◽  
Serovar Typhimurium

ABSTRACT The first committed step in the biosynthesis of heme, an important cofactor of two catalases and a number of cytochromes, is catalyzed by the hemA gene product. Salmonella enterica serovar Typhimurium hemA26::Tn10d (hemA26) was identified in a genetic screen of insertion mutants that were sensitive to hydrogen peroxide. Here we show that the hemA26 mutant respires at half the rate of wild-type cells and is highly susceptible to the effects of oxygen species. Exposure of the hemA26 strain to hydrogen peroxide results in extensive DNA damage and cell death. The chelation of intracellular free iron fully abrogates the sensitivity of this mutant, indicating that the DNA damage results from the iron-catalyzed formation of hydroxyl radicals. The inactivation of heme synthesis does not change the amount of intracellular iron, but by diminishing the rate of respiration, it apparently increases the amount of reducing equivalents available to drive the Fenton reaction. We also report that hydrogen peroxide has opposite effects on the expression of hemA and hemH, the first and last genes of heme biosynthesis pathway, respectively. hemA mRNA levels decrease, while the transcription of hemH is induced by hydrogen peroxide, in an oxyR-dependent manner. The oxyR-dependent induction is suppressed under conditions that accelerate the Fenton reaction by a mechanism that is not yet understood.

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