Hyperosmotic Stress Response of Campylobacter jejuni

Cameron, Andrew D. S.; Frirdich, Emilisa; Huynh, Steven; Parker, Craig T.; Gaynor, Erin C.

doi:10.1128/jb.01409-12

Cited by 72 publications

(79 citation statements)

References 66 publications

(81 reference statements)

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“…Several might be predicted to be at a disadvantage during colonization of the chicken gastrointestinal tract, rather than being enriched, including mutations within trpB, encoding a product required for tryptophan biosynthesis, and waaF, encoding lipopolysaccharide heptosyltransferase, a component of the C. jejuni lipooligosaccharide (LOS). Previous work demonstrated that hyperosmotic stress caused elevated trpB expression, which may be required for osmotic stress resistance and efficient colonization of the chicken gastrointestinal tract (20). Mutation of waaF resulted in a truncated core oligosaccharide, which resulted in increased sensitivity to serum killing and decreased binding to cellular ligands (21).…”

Section: Resultsmentioning

confidence: 99%

High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

Johnson

Livny

DiRita

2014

Journal of Bacteriology

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bCampylobacter jejuni is a leading cause of gastrointestinal infections worldwide, due primarily to its ability to asymptomatically colonize the gastrointestinal tracts of agriculturally relevant animals, including chickens. Infection often occurs following consumption of meat that was contaminated by C. jejuni during harvest. Because of this, much interest lies in understanding the mechanisms that allow C. jejuni to colonize the chicken gastrointestinal tract. To address this, we generated a C. jejuni transposon mutant library that is amenable to insertion sequencing and introduced this mutant pool into day-of-hatch chicks. Following deep sequencing of C. jejuni mutants in the cecal outputs, several novel factors required for efficient colonization of the chicken gastrointestinal tract were identified, including the predicted outer membrane protein MapA. A mutant strain lacking mapA was constructed and found to be significantly reduced for chicken colonization in both competitive infections and monoinfections. Further, we found that mapA is required for in vitro competition with wild-type C. jejuni but is dispensable for growth in monoculture.

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Section: Resultsmentioning

confidence: 99%

High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

Johnson

Livny

DiRita

2014

Journal of Bacteriology

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“…Indeed, in searching the C. jejuni literature, we found that expression of these genes is influenced by multiple regulatory factors or growth conditions. For instance, previous studies have shown that expression of many genes within the Cjj1484-Cjj1483 regulon is reduced under high-iron conditions or by hyperosmotic shock but increased at an acidic pH (51)(52)(53). In addition, the ferric uptake regulator (Fur), which monitors the iron status of the bacterium, largely represses expression of these genes (54).…”

Section: Discussionmentioning

confidence: 99%

Analysis of the Activity and Regulon of the Two-Component Regulatory System Composed by Cjj81176_1484 and Cjj81176_1483 of Campylobacter jejuni

et al. 2015

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Campylobacter jejuni is a leading cause of bacterial diarrheal disease and a frequent commensal of the intestinal tract in poultry and other animals. For optimal growth and colonization of hosts, C. jejuni employs two-component regulatory systems (TCSs) to monitor environmental conditions and promote proper expression of specific genes. We analyzed the potential of C. jejuni Cjj81176_1484 (Cjj1484) and Cjj81176_1483 (Cjj1483) to encode proteins of a cognate TCS that influences expression of genes possibly important for C. jejuni growth and colonization. Transcriptome analysis revealed that the regulons of the Cjj81176_1484 (Cjj1484) histidine kinase and the Cjj81176_1483 (Cjj1483) response regulator contain many common genes, suggesting that these proteins likely form a cognate TCS. We found that this TCS generally functions to repress expression of specific proteins with roles in metabolism, iron/heme acquisition, and respiration. Furthermore, the TCS repressed expression of Cjj81176_0438 and Cjj81176_0439, which had previously been found to encode a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract. However, the TCS and other specific genes whose expression is repressed by the TCS were not required for colonization of chicks. We observed that the Cjj1483 response regulator binds target promoters in both unphosphorylated and phosphorylated forms and influences expression of some specific genes independently of the Cjj1484 histidine kinase. This work further expands the signaling mechanisms of C. jejuni and provides additional insights regarding the complex and multifactorial regulation of many genes involved in basic metabolism, respiration, and nutrient acquisition that the bacterium requires for optimal growth in different environments. IMPORTANCEBacterial two-component regulatory systems (TCSs) link environmental cues to expression of specific genes that enable optimal bacterial growth or colonization of hosts. We found that the Campylobacter jejuni Cjj1484 histidine kinase and Cjj1483 response regulator function as a cognate TCS to largely repress expression of target genes encoding a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract, as well as other genes encoding proteins for heme or iron acquisition, metabolism, and respiration. We also discovered different modes by which Cjj1483 may mediate repression with and without Cjj1484. This work provides insight into the signal transduction mechanisms of a leading cause of bacterial diarrheal disease and emphasizes the multifactorial and complex regulation of specific biological processes in C. jejuni.

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“…A number of previous studies have analyzed the transcriptomes of foodborne pathogens under stress conditions commonly present on/in food matrices (including hyperosmotic stress, cold stress, hydrostatic pressure stress, antimicrobial stress, acid stress, and alkali stress), using laboratory media modified to simulate these conditions as a model (15)(16)(17)(18)(19)(20)(21)(22)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63). These laboratory media include BHI broth (18,20,21,59), BHI agar (19), Luria-Bertani broth (60,61), tryptic soy broth (62), M9-glucose (63), and Listeria minimal medium (22) as reference conditions.…”

Section: Discussionmentioning

confidence: 99%

Transcriptomic Analysis of the Adaptation of Listeria monocytogenes to Growth on Vacuum-Packed Cold Smoked Salmon

Tang

Orsi

Bakker

et al. 2015

Appl Environ Microbiol

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The foodborne pathogen Listeria monocytogenes is able to survive and grow in ready-to-eat foods, in which it is likely to experience a number of environmental stresses due to refrigerated storage and the physicochemical properties of the food. Little is known about the specific molecular mechanisms underlying survival and growth of L. monocytogenes under different complex conditions on/in specific food matrices. Transcriptome sequencing (RNA-seq) was used to understand the transcriptional landscape of L. monocytogenes strain H7858 grown on cold smoked salmon (CSS; water phase salt, 4.65%; pH 6.1) relative to that in modified brain heart infusion broth (MBHIB; water phase salt, 4.65%; pH 6.1) at 7°C. Significant differential transcription of 149 genes was observed (false-discovery rate [FDR], <0.05; fold change, >2.5), and 88 and 61 genes were up-and downregulated, respectively, in H7858 grown on CSS relative to the genes in H7858 grown in MBHIB. In spite of these differences in transcriptomes under these two conditions, growth parameters for L. monocytogenes were not significantly different between CSS and MBHIB, indicating that the transcriptomic differences reflect how L. monocytogenes is able to facilitate growth under these different conditions. Differential expression analysis and Gene Ontology enrichment analysis indicated that genes encoding proteins involved in cobalamin biosynthesis as well as ethanolamine and 1,2-propanediol utilization have significantly higher transcript levels in H7858 grown on CSS than in that grown in MBHIB. Our data identify specific transcriptional profiles of L. monocytogenes growing on vacuum-packaged CSS, which may provide targets for the development of novel and improved strategies to control L. monocytogenes growth on this ready-to-eat food.L isteria monocytogenes is a psychrotolerant foodborne pathogen that causes a potentially severe disease, listeriosis. This pathogen is of particular concern to the ready-to-eat (RTE) meat and seafood industries due to its ability to grow at temperatures as low as Ϫ0.4°C and under conditions of salt content as high as 25% (at 4°C) (1-3). Cold smoked salmon (CSS), an RTE seafood, represents a typical food product that can support the growth of L. monocytogenes from low numbers to potentially hazardous levels (4-9). The heat treatment applied during processing of CSS is not sufficient to inactivate microbes present on the raw material, including L. monocytogenes (10, 11). In addition, RTE food products, including CSS, can be contaminated with L. monocytogenes from environmental sources in processing facilities (10-13). Importantly, typical product characteristics of CSS, including pH, water activity (a w ), salt, and phenolic components, do not seem to be sufficient to control the growth of L. monocytogenes if it is present (8, 9).With the aim of developing control strategies that prevent or reduce growth of this pathogen in RTE seafood products, there is a need for a better understanding of the mechanisms that L. monocytogenes uses to sur...

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Hyperosmotic Stress Response of Campylobacter jejuni

Cited by 72 publications

References 66 publications

High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

Analysis of the Activity and Regulon of the Two-Component Regulatory System Composed by Cjj81176_1484 and Cjj81176_1483 of Campylobacter jejuni

Transcriptomic Analysis of the Adaptation of Listeria monocytogenes to Growth on Vacuum-Packed Cold Smoked Salmon

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