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Gaskin DJH, van Vliet AHM. Random mutagenesis strategies for Campylobacter and Helicobacter species. Methods Mol Biol 2010; 634:37-52. [PMID: 20676974 DOI: 10.1007/978-1-60761-652-8_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Campylobacter and Helicobacter species are important pathogens in man and animals. The study of their virulence and physiology has been difficult due to the lack of tractable genetic tools, since many of the techniques established in Escherichia coli and related species were found to be non-functional in Campylobacter and Helicobacter species. The advent of functional genomics techniques in the last decade has been accompanied by the development of genetic tools, which take advantage of specific features of Campylobacter and Helicobacter, like natural transformation. This has allowed for the construction of random mutant libraries based on in vitro transposition or ligated loops followed by natural transformation and recombination, thus circumventing selection against sequences when cloning or passaging libraries through E. coli. Uses of the techniques have been in the study of motility, gene expression, and gene essentiality. In this chapter, we discuss the approaches and techniques used for the construction of random mutant libraries in both Campylobacter and Helicobacter.
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Wainwright LM, Elvers KT, Park SF, Poole RK. A truncated haemoglobin implicated in oxygen metabolism by the microaerophilic food-borne pathogen Campylobacter jejuni. Microbiology (Reading) 2005; 151:4079-4091. [PMID: 16339953 DOI: 10.1099/mic.0.28266-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Of the three groups of haemoglobins identified in micro-organisms (single-domain globins, flavohaemoglobins and truncated globins), the last group is the least well understood. The function of the truncated haemoglobin (Ctb) encoded by Cj0465c in the microaerophilic food-borne bacterial pathogenCampylobacter jejuniwas investigated by constructing actbmutant and characterizing its phenotype. The effects of thectbmutation on the kinetics of terminal oxidase function inC. jejuniwere investigated using oxyleghaemoglobin and oxymyoglobin as sensitive reporters of O2consumption. TheVmaxofctbmutant cells for O2, calculated using either globin, was greater than that of wild-type cells at extracellular O2concentrations up to ∼1 μM, suggesting a role for Ctb in moderating O2supply for reduction by high-affinity terminal oxidases. However, cells mutated inctbwere disadvantaged when grown under conditions of high aeration, as revealed by measurements of growth yields and rates in batch culture. Furthermore, the rate at whichctbmutant cells consumed O2in an O2electrode (10–200 μM O2) was approximately half the rate displayed by wild-type cells, reflecting a role for Ctb in respiration at physiologically relevant external O2concentrations. However, a lack of sensitivity of the mutant to paraquat or H2O2indicated that increased oxidative stress under such conditions was not the cause of these phenotypes. O2affinities of cells (Kmvalues of approximately 40 nM and 1 μM) were unaffected by mutation of either Ctb or the full-lengthC. jejuniglobin, Cgb. Although the gene encoding Ctb was found to be upregulated byS-nitrosoglutathione (GSNO) and the NO-donating compoundS-nitroso-N-acetylpenicillamine (SNAP), actbmutant did not display sensitivity to a number of nitrosative stress-generating compounds. The authors conclude that Ctb is involved in moderating O2flux withinC. jejuni.
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Affiliation(s)
- Laura M Wainwright
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, UK
| | - Karen T Elvers
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Simon F Park
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Robert K Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, UK
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Elvers KT, Wu G, Gilberthorpe NJ, Poole RK, Park SF. Role of an inducible single-domain hemoglobin in mediating resistance to nitric oxide and nitrosative stress in Campylobacter jejuni and Campylobacter coli. J Bacteriol 2004; 186:5332-41. [PMID: 15292134 PMCID: PMC490904 DOI: 10.1128/jb.186.16.5332-5341.2004] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Accepted: 05/17/2004] [Indexed: 11/20/2022] Open
Abstract
Campylobacter jejuni expresses two hemoglobins, each of which exhibits a heme pocket and structural signatures in common with vertebrate and plant globins. One of these, designated Cgb, is homologous to Vgb from Vitreoscilla stercoraria and does not possess the reductase domain seen in the flavohemoglobins. A Cgb-deficient mutant of C. jejuni was hypersensitive to nitrosating agents (S-nitrosoglutathione [GSNO] or sodium nitroprusside) and a nitric oxide-releasing compound (spermine NONOate). The sensitivity of the Cgb-deficient mutant to methyl viologen, hydrogen peroxide, and organic peroxides, however, was the same as for the wild type. Consistent with the protective role of Cgb against NO-related stress, cgb expression was minimal in standard laboratory media but strongly and specifically induced after exposure to nitrosative stress. In contrast, the expression of Cgb was independent of aeration and the presence of superoxide. In the absence of preinduction by exposure to nitrosative stress, no difference was seen in the degree of respiratory inhibition by NO or the half-life of the NO signal when cells of the wild type and the cgb mutant were compared. However, cells expressing GSNO-upregulated levels of Cgb exhibited robust NO consumption and respiration that was relatively NO insensitive compared to the respiration of the cgb mutant. Based on similar studies in Campylobacter coli, we also propose an identical role for Cgb in this closely related species. We conclude that, unlike the archetypal single-domain globin Vgb, Cgb forms a specific and inducible defense against NO and nitrosating agents.
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Affiliation(s)
- Karen T Elvers
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, United Kingdom
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Park SF, Purdy D, Leach S. Localized reversible frameshift mutation in the flhA gene confers phase variability to flagellin gene expression in Campylobacter coli. J Bacteriol 2000; 182:207-10. [PMID: 10613882 PMCID: PMC94259 DOI: 10.1128/jb.182.1.207-210.2000] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phase variation of flagellin gene expression in Campylobacter coli UA585 was correlated with high-frequency, reversible insertion and deletion frameshift mutations in a short homopolymeric tract of thymine residues located in the N-terminal coding region of the flhA gene. Mutation-based phase variation in flhA may generate functional diversity in the host and environment.
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Affiliation(s)
- S F Park
- School of Biological Sciences, University of Surrey, Guildford, GU2 5XH, United Kingdom.
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Purdy D, Cawthraw S, Dickinson JH, Newell DG, Park SF. Generation of a superoxide dismutase (SOD)-deficient mutant of Campylobacter coli: evidence for the significance of SOD in Campylobacter survival and colonization. Appl Environ Microbiol 1999; 65:2540-6. [PMID: 10347040 PMCID: PMC91375 DOI: 10.1128/aem.65.6.2540-2546.1999] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The microaerophilic nature of Campylobacter species implies an inherent sensitivity towards oxygen and its reduction products, particularly the superoxide anion. The deleterious effects of exposure to superoxide radicals are counteracted by the activity of superoxide dismutase (SOD). We have shown previously that Campylobacter coli possesses an iron cofactored SOD. The sodB gene of C. coli UA585 was insertionally inactivated by the site-specific insertion of a tetO cassette. Organisms harboring the inactivated gene failed to produce a biologically functional form of the enzyme. While the ability of this mutant to grow in aerobic conditions was unchanged relative to the parental strain, its survival was severely compromised when nongrowing cells were exposed to air. Accordingly, the SOD-deficient mutant was unable to survive for prolonged periods in model foods. Furthermore, inactivation of the sodB gene decreased the colonization potential in an experimental infection of 1-day-old chicks. In contrast, strain CK100, which is deficient in catalase activity, showed the same survival and colonization characteristics as the parental strain. These results indicate that SOD, but not catalase, is an important determinant in the ability of C. coli to survive aerobically and for optimal colonization within the chicken gut.
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Affiliation(s)
- D Purdy
- Centre for Applied Microbiology Research, Porton Down, Salisbury SP4 0JG, United Kingdom
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Bijlsma JJ, Vandenbroucke-Grauls CM, Phadnis SH, Kusters JG. Identification of virulence genes of Helicobacter pylori by random insertion mutagenesis. Infect Immun 1999; 67:2433-40. [PMID: 10225906 PMCID: PMC115989 DOI: 10.1128/iai.67.5.2433-2440.1999] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The complete genome of the gram-negative bacterial pathogen Helicobacter pylori, an important etiological agent of gastroduodenal disease in humans, has recently been published. This sequence revealed that the putative products of roughly one-third of the open reading frames (ORFs) have no significant homology to any known proteins. To be able to analyze the functions of all ORFs, we constructed an integration plasmid for H. pylori and used it to generate a random mutant library in this organism. This integration plasmid, designated pBCalpha3, integrated randomly into the chromosome of H. pylori. To test the capacity of this library to identify virulence genes, subsets of this library were screened for urease-negative mutants and for nonmotile mutants. Three urease-negative mutants in a subset of 1,251 mutants (0.25%) and 5 nonmotile mutants in a subset of 180 mutants (2.7%) were identified. Analysis of the disrupted ORFs in the urease-negative mutants revealed that two had disruptions of genes of the urease locus, ureB and ureI, and the third had a disruption of a unrelated gene; a homologue of deaD, which encodes an RNA helicase. Analysis of the disrupted ORFs in the nonmotile mutants revealed one ORF encoding a homologue of the paralyzed flagellar protein, previously shown to be involved in motility in Campylobacter jejuni. The other four ORFs have not been implicated in motility before. Based on these data, we concluded that we have generated a random insertion library in H. pylori that allows for the functional identification of genes in H. pylori.
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Affiliation(s)
- J J Bijlsma
- Department of Medical Microbiology, Faculty of Medicine, Vrije Universiteit Amsterdam, The Netherlands
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Park SF. The use of hipO, encoding benzoylglycine amidohydrolase (hippuricase), as a reporter of gene expression in Campylobacter coli. Lett Appl Microbiol 1999; 28:285-90. [PMID: 10212441 DOI: 10.1046/j.1365-2672.1999.00524.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A novel integrative promoter probe vector which utilizes the Campylobacter jejuni hipO gene as a reporter of gene expression was developed as a genetic tool in Campylobacter coli. The utility of the system was demonstrated by coupling expression of the hipO reporter to the promoters of flaA, flaB and katA. Subsequently, expression of these genes could be monitored accurately from chromosomally-borne transcriptional fusions using a simple non-destructive colorimetric assay. The system should serve as a useful tool for studying the response of Camp. coli to environmental stresses.
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Affiliation(s)
- S F Park
- School of Biological Sciences, University of Surrey, Guildford, UK.
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Van Vliet AH, Wood AC, Wooldridge K, Ketley JM, Henderson J. 7.7 Genetic Manipulation of Enteric Campylobacter Species. METHODS IN MICROBIOLOGY 1998. [DOI: 10.1016/s0580-9517(08)70301-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Richardson PT, Park SF. Integration of heterologous plasmid DNA into multiple sites on the genome of Campylobacter coli following natural transformation. J Bacteriol 1997; 179:1809-12. [PMID: 9045845 PMCID: PMC178898 DOI: 10.1128/jb.179.5.1809-1812.1997] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The efficiency of homologous recombination in Campylobacter coli following the introduction of DNA by natural transformation was determined by using a series of nonreplicating integrative vectors containing DNA fragments derived from the C. coli catalase gene. Homologous recombination occurred with as little as 286 homologous bp present and was not detected when 270 bases of homology was provided. Instead, when plasmids with little or no homology to the chromosome were introduced by natural transformation, the vector DNA became chromosomally integrated at random sites scattered throughout the C. coli genome. Southern analysis and nucleotide sequencing revealed that recombination had occurred between nonhomologous sequences and can therefore be described as illegitimate. There were at least five different recombination sites on plasmid pSP105. The ability of C. coli to acquire heterologous plasmids by natural transformation, and maintain them by chromosomal integration following illegitimate recombination, has fascinating implications for the genomic diversity and evolution of this species.
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Affiliation(s)
- P T Richardson
- Institute of Food Research, Reading Laboratory, United Kingdom
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Grant KA, Park SF. Molecular characterization of katA from Campylobacter jejuni and generation of a catalase-deficient mutant of Campylobacter coli by interspecific allelic exchange. MICROBIOLOGY (READING, ENGLAND) 1995; 141 ( Pt 6):1369-1376. [PMID: 7670638 DOI: 10.1099/13500872-141-6-1369] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A gene encoding catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase; EC 1.11.1.6) from Campylobacter jejuni was cloned by functional complementation of a catalase-deficient mutant of Escherichia coli. The catalase structural gene, designated katA, was assigned by subcloning and its nucleotide sequence determined. The deduced protein product of 508 amino acids, which had a calculated molecular mass of 58,346 Da, was found to be structurally and enzymically similar to hydrogen-peroxidases from other bacterial species. The region of DNA containing the structural catalase gene was disrupted by insertion of a tetracycline-resistance marker and the modified sequence then introduced into a strain of Campylobacter coli via natural transformation. Genetic and enzymic analyses of a tetracycline-resistant C. coli transformant confirmed that catalase-deficient mutants had arisen via interspecific allelic exchange. Compared to the isogenic parental strain the mutant was more sensitive to killing by H2O2.
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Affiliation(s)
- Kathleen A Grant
- Institute of Food Research, Reading Laboratory,Earley Gate, Whiteknights Road, Reading, RG6 2EF,UK
| | - Simon F Park
- Institute of Food Research, Reading Laboratory,Earley Gate, Whiteknights Road, Reading, RG6 2EF,UK
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