Changes in Gene Transcription Induced by Hydrogen Peroxide Treatment of Verotoxin-Producing Escherichia coli O157:H7 and Non-O157 Serotypes on Romaine Lettuce

Mei, Gui-Ying; Tang, Joshua; Bach, Susan; Kostrzynska, Magdalena

doi:10.3389/fmicb.2017.00477

Cited by 12 publications

(15 citation statements)

References 86 publications

(109 reference statements)

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“…No significant differences in Sytox Green accessibility was detected between cells isolated from treated cultures and untreated cultures when stationary phase ETEC cultures incubated for 3 h at 37 • C in the presence or absence of up to 20 mM hydrogen peroxide, revealing intact membranes (Supplementary Figure 2). We note that this concentration of hydrogen peroxide is higher than typically used in reports of oxidative stress in laboratory (K12) strains of E. coli, and that higher concentrations (up to 50 mM) of hydrogen peroxide are usually necessary to induce stress in studies of pathogenic E. coli (Bearson et al, 2009;Felicio et al, 2009;Łoś et al, 2010;Mei et al, 2017). To validate that our treatment conditions nevertheless did result in oxidation of ETEC proteins, we analyzed whole cell extracts and observed an increase in oxidative carbonyl modifications (Supplementary Figure 3).…”

Section: Isolation and Proteomic Analysis Of Omvs Produced After Oxidative Stressmentioning

confidence: 84%

Differential Packaging Into Outer Membrane Vesicles Upon Oxidative Stress Reveals a General Mechanism for Cargo Selectivity

Orench‐Rivera

Kuehn

2021

Front. Microbiol.

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Selective cargo packaging into bacterial extracellular vesicles has been reported and implicated in many biological processes, however, the mechanism behind the selectivity has remained largely unexplored. In this study, proteomic analysis of outer membrane (OM) and OM vesicle (OMV) fractions from enterotoxigenic E. coli revealed significant differences in protein abundance in the OMV and OM fractions for cultures shifted to oxidative stress conditions. Analysis of sequences of proteins preferentially packaged into OMVs showed that proteins with oxidizable residues were more packaged into OMVs in comparison with those retained in the membrane. In addition, the results indicated two distinct classes of OM-associated proteins were differentially packaged into OMVs as a function of peroxide treatment. Implementing a Bayesian hierarchical model, OM lipoproteins were determined to be preferentially exported during stress whereas integral OM proteins were preferentially retained in the cell. Selectivity was determined to be independent of transcriptional regulation of the proteins upon oxidative stress and was validated using randomly selected protein candidates from the different cargo classes. Based on these data, a hypothetical functional and mechanistic basis for cargo selectivity was tested using OmpA constructs. Our study reveals a basic mechanism for cargo selectivity into OMVs that may be useful for the engineering of OMVs for future biotechnological applications.

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Section: Isolation and Proteomic Analysis Of Omvs Produced After Oxidative Stressmentioning

confidence: 84%

Differential Packaging Into Outer Membrane Vesicles Upon Oxidative Stress Reveals a General Mechanism for Cargo Selectivity

Orench‐Rivera

Kuehn

2021

Front. Microbiol.

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“…Past efforts showed that various stress conditions induced changes in E. coli gene expression in both pure culture and on non-host environments such as fresh lettuce (Allen and Griffiths, 2012;Mei et al, 2017). In this study, we analyzed the dynamic co-expression networks of E. coli in response to different doses of ClO 2 on non-host tomato surfaces, which could serve as a pre-exposure to another stressor causing either cross-protection or cross-vulnerability (Zorraquino et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Xenobiotic Effects of Chlorine Dioxide to Escherichia coli O157:H7 on Non-host Tomato Environment Revealed by Transcriptional Network Modeling: Implications to Adaptation and Selection

et al. 2020

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Escherichia coli serotype O157:H7 is one of the major agents of pathogen outbreaks associated with fresh fruits and vegetables. Gaseous chlorine dioxide (ClO 2) has been reported to be an effective intervention to eliminate bacterial contamination on fresh produce. Although remarkable positive effects of low doses of ClO 2 have been reported, the genetic regulatory machinery coordinating the mechanisms of xenobiotic effects and the potential bacterial adaptation remained unclear. This study examined the temporal transcriptome profiles of E. coli O157:H7 during exposure to different doses of ClO 2 in order to elucidate the genetic mechanisms underlying bacterial survival under such harsh conditions. Dosages of 1 µg, 5 µg, and 10 µg ClO 2 per gram of tomato fruits cause different effects with dose-by-time dynamics. The first hour of exposure to 1 µg and 5 µg ClO 2 caused only partial killing with significant growth reduction starting at the second hour, and without further significant reduction at the third hour. However, 10 µg ClO 2 exposure led to massive bacterial cell death at 1 h with further increase in cell death at 2 and 3 h. The first hour exposure to 1 µg ClO 2 caused activation of primary defense and survival mechanisms. However, the defense response was attenuated during the second and third hours. Upon treatment with 5 µg ClO 2 , the transcriptional networks showed massive downregulation of pathogenesis and stress response genes at the first hour of exposure, with decreasing number of differentially expressed genes at the second and third hours. In contrast, more genes were further downregulated with exposure to 10 µg ClO 2 at the first hour, with the number of both upregulated and downregulated genes significantly decreasing at the second hour.

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“…Average RPKM were transformed using the Propensity Transformation methodology that was optimized from the ClO 2 study on E . coli [ 66 ] based on the following equation: …”

Section: Methodsmentioning

confidence: 99%

Responses of Escherichia coli and Listeria monocytogenes to ozone treatment on non-host tomato: Efficacy of intervention and evidence of induced acclimation

et al. 2021

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Because of the continuous rise of foodborne illnesses caused by the consumption of raw fruits and vegetables, effective post-harvest anti-microbial strategies are necessary. The aim of this study was to evaluate the anti-microbial efficacy of ozone (O3) against two common causes of fresh produce contamination, the Gram-negative Escherichia coli O157:H7 and Gram-positive Listeria monocytogenes, and to relate its effects to potential mechanisms of xenobiosis by transcriptional network modeling. The study on non-host tomato environment correlated the dose × time aspects of xenobiosis by examining the correlation between bacterial survival in terms of log-reduction and defense responses at the level of gene expression. In E. coli, low (1 μg O3/g of fruit) and moderate (2 μg O3/g of fruit) doses caused insignificant reduction in survival, while high dose (3 μg/g of fruit) caused significant reduction in survival in a time-dependent manner. In L. monocytogenes, moderate dose caused significant reduction even with short-duration exposure. Distinct responses to O3 xenobiosis between E. coli and L. monocytogenes are likely related to differences in membrane and cytoplasmic structure and components. Transcriptome profiling by RNA-Seq showed that primary defenses in E. coli were attenuated after exposure to a low dose, while the responses at moderate dose were characterized by massive upregulation of pathogenesis and stress-related genes, which implied the activation of defense responses. More genes were downregulated during the first hour at high dose, with a large number of such genes getting significantly upregulated after 2 hr and 3 hr. This trend suggests that prolonged exposure led to potential adaptation. In contrast, massive downregulation of genes was observed in L. monocytogenes regardless of dose and exposure duration, implying a mechanism of defense distinct from that of E. coli. The nature of bacterial responses revealed by this study should guide the selection of xenobiotic agents for eliminating bacterial contamination on fresh produce without overlooking the potential risks of adaptation.

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Changes in Gene Transcription Induced by Hydrogen Peroxide Treatment of Verotoxin-Producing Escherichia coli O157:H7 and Non-O157 Serotypes on Romaine Lettuce

Cited by 12 publications

References 86 publications

Differential Packaging Into Outer Membrane Vesicles Upon Oxidative Stress Reveals a General Mechanism for Cargo Selectivity

Differential Packaging Into Outer Membrane Vesicles Upon Oxidative Stress Reveals a General Mechanism for Cargo Selectivity

Xenobiotic Effects of Chlorine Dioxide to Escherichia coli O157:H7 on Non-host Tomato Environment Revealed by Transcriptional Network Modeling: Implications to Adaptation and Selection

Responses of Escherichia coli and Listeria monocytogenes to ozone treatment on non-host tomato: Efficacy of intervention and evidence of induced acclimation

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