The
            <i>Campylobacter jejuni</i>
            Thiol Peroxidases Tpx and Bcp Both Contribute to Aerotolerance and Peroxide-Mediated Stress Resistance but Have Distinct Substrate Specificities

Atack, John M.; Harvey, Philippa; Jones, Michael A.; Kelly, David J.

doi:10.1128/jb.00100-08

Cited by 76 publications

(73 citation statements)

References 46 publications

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“…C. jejuni NCTC11168 contains one catalase (KatA), two cytochrome c peroxidases (Cj0358 and Cj0020c), and three peroxiredoxins (AhpC, Tpx, and Bcp) (34). KatA, Tpx, and Bcp have been shown to contribute, at least to some extent, to H 2 O 2 detoxification in C. jejuni (5,17), and Cj0358 and Cj0020c have been demonstrated to have peroxidase activity (11). AhpC has also been demonstrated to scavenge H 2 O 2 in E. coli (39) and likely performs a similar function in C. jejuni.…”

Section: Discussionmentioning

confidence: 99%

Cj1386 Is an Ankyrin-Containing Protein Involved in Heme Trafficking to Catalase in Campylobacter jejuni

2012

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Campylobacter jejuni, a microaerophilic bacterium, is the most frequent cause of human bacterial gastroenteritis. C. jejuni is exposed to harmful reactive oxygen species (ROS) produced during its own normal metabolic processes and during infection from the host immune system and from host intestinal microbiota. These ROS will damage DNA and proteins and cause peroxidation of lipids. Consequently, identifying ROS defense mechanisms is important for understanding how Campylobacter survives this environmental stress during infection. Construction of a ⌬Cj1386 isogenic deletion mutant and phenotypic assays led to its discovery as a novel oxidative stress defense gene. The ⌬Cj1386 mutant has an increased sensitivity toward hydrogen peroxide. The Cj1386 gene is located directly downstream from katA (catalase) in the C. jejuni genome. A ⌬katA⌬ Cj1386 double deletion mutant was constructed and exhibited a sensitivity to hydrogen peroxide similar to that seen in the ⌬Cj1386 and ⌬katA single deletion mutants. This observation suggests that Cj1386 may be involved in the same detoxification pathway as catalase. Despite identical KatA abundances, catalase activity assays showed that the ⌬Cj1386 mutant had a reduced catalase activity relative to that of wild-type C. jejuni. Heme quantification of KatA protein from the ⌬Cj1386 mutant revealed a significant decrease in heme concentration. This indicates an important role for Cj1386 in heme trafficking to KatA within C. jejuni. Interestingly, the ⌬Cj1386 mutant had a reduced ability to colonize the ceca of chicks and was outcompeted by the wild-type strain for colonization of the gastrointestinal tract of neonate piglets. These results indicate an important role for Cj1386 in Campylobacter colonization and pathogenesis.

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Section: Discussionmentioning

confidence: 99%

Cj1386 Is an Ankyrin-Containing Protein Involved in Heme Trafficking to Catalase in Campylobacter jejuni

2012

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“…Induction of ahpC, sodB and tpx, which have functions in oxidative and nitrosative stress resistance, provides further examples of the upregulation of stress response genes during stationary phase (Atack et al, 2008;Baillon et al, 1999;Purdy et al, 1999). Protein damage in the form of carbonylation and disulphide bond formation is known to accumulate in E. coli stationary-phase cultures (Dukan & Nystrom, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…Although C. jejuni lacks any homologue of rpoH, the stationary-phase induction of heat shock genes may represent a similar response to protein damage, albeit regulated by a different mechanism. Similarly, oxidative stress-resistance genes, such as sodB and tpx, are important in resisting the types of protein damage that are known to accumulate in stationary phase cultures (Atack et al, 2008;Dukan & Nystrom, 1999). Interestingly, AhpC and Tpx have been shown by proteomic methods to be upregulated in C. jejuni biofilms (Kalmokoff et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Metabolite and transcriptome analysis of Campylobacter jejuni in vitro growth reveals a stationary-phase physiological switch

et al. 2009

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Campylobacter jejuni is a prevalent cause of food-borne diarrhoeal illness in humans. Understanding of the physiological and metabolic capabilities of the organism is limited. We report a detailed analysis of the C. jejuni growth cycle in batch culture. Combined transcriptomic, phenotypic and metabolic analysis demonstrates a highly dynamic 'stationary phase', characterized by a peak in motility, numerous gene expression changes and substrate switching, despite transcript changes that indicate a metabolic downshift upon the onset of stationary phase. Video tracking of bacterial motility identifies peak activity during stationary phase. Amino acid analysis of culture supernatants shows a preferential order of amino acid utilization. Proton NMR ( 1 H-NMR) highlights an acetate switch mechanism whereby bacteria change from acetate excretion to acetate uptake, most probably in response to depletion of other substrates. Acetate production requires pta (Cj0688) and ackA (Cj0689), although the acs homologue (Cj1537c) is not required. Insertion mutants in Cj0688 and Cj0689 maintain viability less well during the stationary and decline phases of the growth cycle than wild-type C. jejuni, suggesting that these genes, and the acetate pathway, are important for survival. INTRODUCTIONCampylobacter jejuni is the major cause of food-borne bacterial gastroenteritis worldwide, with an estimated 1 in 100 individuals in both the USA and the UK developing Campylobacter-related illness each year (Gaynor et al., 2004;Gillespie et al., 2002). Although most cases are selflimiting, C. jejuni can cause severe post-infection complications including the peripheral neuropathies GuillainBarré and Miller-Fisher syndromes (Nachamkin et al., 2000). Despite the significance of C. jejuni as a food-borne pathogen, our understanding of its basic biochemistry and physiology, gene regulation, colonization, virulence and environmental survival mechanisms lags behind that of many other pathogenic and non-pathogenic bacteria, and many questions regarding C. jejuni physiology and pathogenesis remain (Young et al., 2007). Research has been hampered by a lack of genetic tools, the difficulty of growing the bacteria in the laboratory and the absence of a suitable animal model that mimics human disease.C. jejuni is a fastidious bacterium, with a limited capacity for biosynthesis, and requires complex growth media (Kelly, 2001). Establishing the metabolic capabilities of C. jejuni is central to comprehension of environmental persistence and host colonization. The microaerophilic nature, complex nutritional requirements and relative difficulty of culturing C. jejuni have all contributed to the limited understanding of metabolism (Kelly, 2001(Kelly, , 2005Sellars et al., 2002). C. jejuni is unable to catabolize glucose and other hexose sugars due to the absence of the key glycolytic enzyme 6-phosphofructokinase (Parkhill et al., 2000;Velayudhan & Kelly, 2002 The importance of each amino acid in C. jejuni metabolism is yet to be fully established, however, and i...

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“…It should be noted, of course, that like many bacteria, C. jejuni contains a plethora of enzymes able to detoxify peroxides, such as catalase (Grant & Park, 1995), cytochrome c peroxidases (Atack & Kelly, 2007), AhpC (Baillon et al, 1999), and Tpx and Bcp (Atack et al, 2008). Although these appear to be able to detoxify hydrogen peroxide, peroxide exposure must cause some oxidation of methionine residues to account for the effects seen.…”

Section: Discussionmentioning

confidence: 99%

Contribution of the stereospecific methionine sulphoxide reductases MsrA and MsrB to oxidative and nitrosative stress resistance in the food-borne pathogen Campylobacter jejuni

Atack

Kelly

2008

Microbiology

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The microaerophilic food-borne pathogen Campylobacter jejuni is exposed to highly variable oxygen concentrations during its life cycle and employs a variety of protection mechanisms to resist oxidative stress. However, not all of the enzymes that mediate such protection have yet been identified. Two genes in strain NCTC 11168, Cj0637c and Cj1112c, are predicted to encode unrelated methionine sulphoxide reductases, which may repair oxidized methionine residues in proteins and thus contribute to oxidative stress defence. Cj0637 and Cj1112 were overexpressed, purified and shown by a coupled thioredoxin-thioredoxin reductase-NADPH assay to catalyse the stereospecific reduction of the S and R diastereoisomers, respectively, of the model compound methyl p-tolyl sulphoxide. Cj0637 is thus identified as MsrA and Cj1112 as MsrB. The contribution of these enzymes to oxidative and nitrosative stress resistance in C. jejuni was assessed by phenotypic analysis of a set of isogenic msrA, msrB and msrA/B insertion mutants. As RT-PCR data suggested a polar effect on Cj1111c in the msrB mutant, an msrB/ msrB + merodiploid complementation strain was also constructed. The msrA/B strain was severely growth inhibited under standard microaerobic conditions, whereas the msrA and msrB strains grew normally. Agar plate disc diffusion assays showed that all mutants displayed increased sensitivity to hydrogen peroxide, organic peroxide, superoxide, and nitrosative and disulphide stress, but quantitative cell viability assays showed that the msrA/B double mutant was markedly more sensitive to both oxidative and nitrosative stress. All of the stress-sensitivity phenotypes observed for the msrB mutant were restored to wild-type in the msrB/msrB + merodiploid. It is concluded that MsrA and MsrB make a significant contribution to the protection of C. jejuni against oxidative and nitrosative stress.

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The Campylobacter jejuni Thiol Peroxidases Tpx and Bcp Both Contribute to Aerotolerance and Peroxide-Mediated Stress Resistance but Have Distinct Substrate Specificities

Cited by 76 publications

References 46 publications

Cj1386 Is an Ankyrin-Containing Protein Involved in Heme Trafficking to Catalase in Campylobacter jejuni

Cj1386 Is an Ankyrin-Containing Protein Involved in Heme Trafficking to Catalase in Campylobacter jejuni

Metabolite and transcriptome analysis of Campylobacter jejuni in vitro growth reveals a stationary-phase physiological switch

Contribution of the stereospecific methionine sulphoxide reductases MsrA and MsrB to oxidative and nitrosative stress resistance in the food-borne pathogen Campylobacter jejuni

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