1887

Abstract

The O157 : H7 TW14359 strain was implicated in a multi-state outbreak in North America in 2006, which resulted in high rates of severe disease. Similarly, the O157 : H7 RIMD0509952 (Sakai) strain caused the largest O157 : H7 outbreak to date. Both strains were shown to represent divergent phylogenetic lineages. Here we compared global gene expression patterns before and after epithelial cell exposure, as well as the ability to adhere to and invade epithelial cells, between the two outbreak strains. Epithelial cell assays demonstrated a 2.5-fold greater adherence of the TW14359 strain relative to Sakai, while whole-genome microarrays detected significant differential expression of 914 genes, 206 of which had a fold change ≥1.5. Interestingly, most locus of enterocyte effacement (LEE) genes were upregulated in TW14359, whereas flagellar and chemotaxis genes were primarily upregulated in Sakai, suggesting discordant expression of these genes between the two strains. The Shiga toxin 2 genes were also upregulated in the TW14359 strain, as were several pO157-encoded genes that promote adherence, including type II secretion genes and their effectors and . Quantitative RT-PCR confirmed the expression differences detected in the microarray analysis, and expression levels were lower for a subset of LEE genes before versus after exposure to epithelial cells. In all, this study demonstrated the upregulation of major and ancillary virulence genes in TW14359 and of flagellar and chemotaxis genes in Sakai, under conditions that precede intimate bacterial attachment to epithelial cells. Differences in the level of adherence to epithelial cells were also observed, implying that these two phylogenetically divergent O157 : H7 outbreak strains vary in their ability to colonize, or initiate the disease process.

Loading

Article metrics loading...

/content/journal/micro/10.1099/mic.0.033126-0
2010-02-01
2020-01-17
Loading full text...

Full text loading...

/deliver/fulltext/micro/156/2/408.html?itemId=/content/journal/micro/10.1099/mic.0.033126-0&mimeType=html&fmt=ahah

References

  1. Abe, H., Tatsuno, I., Tobe, T., Okutani, A. & Sasakawa, C. ( 2002; ). Bicarbonate ion stimulates the expression of locus of enterocyte effacement-encoded genes in enterohemorrhagic Escherichia coli O157 : H7. Infect Immun 70, 3500–3509.[CrossRef]
    [Google Scholar]
  2. Allen-Vercoe, E. & Woodward, M. J. ( 1999; ). The role of flagella, but not fimbriae, in the adherence of Salmonella enterica serotype Enteritidis to chick gut explant. J Med Microbiol 48, 771–780.[CrossRef]
    [Google Scholar]
  3. Barba, J., Bustamante, V. H., Flores-Valdez, M. A., Deng, W., Finlay, B. B. & Puente, J. L. ( 2005; ). A positive regulatory loop controls expression of the locus of enterocyte effacement-encoded regulators Ler and GrlA. J Bacteriol 187, 7918–7930.[CrossRef]
    [Google Scholar]
  4. Barrett, T., Troup, D. B., Wilhite, S. E., Ledoux, P., Rudnev, D., Evangelista, C., Kim, I. F., Soboleva, A., Tomashevsky, M. & other authors ( 2009; ). NCBI GEO: archive for high-throughput functional genomic data. Nucleic Acids Res 37, D885–D890.[CrossRef]
    [Google Scholar]
  5. Beltrametti, F., Kresse, A. U. & Guzman, C. A. ( 1999; ). Transcriptional regulation of the esp genes of enterohemorrhagic Escherichia coli. J Bacteriol 181, 3409–3418.
    [Google Scholar]
  6. Bergholz, T. M., Wick, L. M., Qi, W., Riordan, J. T., Ouellette, L. M. & Whittam, T. S. ( 2007; ). Global transcriptional response of Escherichia coli O157 : H7 to growth transitions in glucose minimal medium. BMC Microbiol 7, 97 [CrossRef]
    [Google Scholar]
  7. Bhagwat, A. A., Phadke, R. P., Wheeler, D., Kalantre, S., Gudipati, M. & Bhagwat, M. ( 2003; ). Computational methods and evaluation of RNA stabilization reagents for genome-wide expression studies. J Microbiol Methods 55, 399–409.[CrossRef]
    [Google Scholar]
  8. Blattner, F. R., Plunkett, G., III, Bloch, C. A., Perna, N. T., Burland, V., Riley, M., Collado-Vides, J., Glasner, J. D., Rode, C. K. & other authors ( 1997; ). The complete genome sequence of Escherichia coli K-12. Science 277, 1453–1474.[CrossRef]
    [Google Scholar]
  9. Boerlin, P., McEwen, S. A., Boerlin-Petzold, F., Wilson, J. B., Johnson, R. P. & Gyles, C. L. ( 1999; ). Associations between virulence factors of Shiga toxin-producing Escherichia coli and disease in humans. J Clin Microbiol 37, 497–503.
    [Google Scholar]
  10. Burland, V., Shao, Y., Perna, N. T., Plunkett, G., Sofia, H. J. & Blattner, F. R. ( 1998; ). The complete DNA sequence and analysis of the large virulence plasmid of Escherichia coli O157 : H7. Nucleic Acids Res 26, 4196–4204.[CrossRef]
    [Google Scholar]
  11. CDPH ( 2007; ). Investigation of an Escherichia coli O157 : H7 Outbreak Associated with Dole Pre-Packaged Spinach Final March 21, 2007. http://www.cdph.ca.gov/pubsforms/Documents/fdb%20eru%20Spnch%20EC%20Dole032007wph.PDF.
  12. Celli, J., Olivier, M. & Finlay, B. B. ( 2001; ). Enteropathogenic Escherichia coli mediates antiphagocytosis through the inhibition of PI 3-kinase-dependent pathways. EMBO J 20, 1245–1258.[CrossRef]
    [Google Scholar]
  13. Cui, X. & Churchill, G. A. ( 2003; ). Statistical tests for differential expression in cDNA microarray experiments. Genome Biol 4, 210 [CrossRef]
    [Google Scholar]
  14. Cui, X., Hwang, J. T., Qiu, J., Blades, N. J. & Churchill, G. A. ( 2005; ). Improved statistical tests for differential gene expression by shrinking variance components estimates. Biostatistics 6, 59–75.[CrossRef]
    [Google Scholar]
  15. Dahan, S., Knutton, S., Shaw, R. K., Crepin, V. F., Dougan, G. & Frankel, G. ( 2004; ). Transcriptome of enterohemorrhagic Escherichia coli O157 adhering to eukaryotic plasma membranes. Infect Immun 72, 5452–5459.[CrossRef]
    [Google Scholar]
  16. Dahan, S., Wiles, S., La Ragione, R. M., Best, A., Woodward, M. J., Stevens, M. P., Shaw, R. K., Chong, Y., Knutton, S. & other authors ( 2005; ). EspJ is a prophage-carried type III effector protein of attaching and effacing pathogens that modulates infection dynamics. Infect Immun 73, 679–686.[CrossRef]
    [Google Scholar]
  17. Deng, W., Puente, J. L., Gruenheid, S., Li, Y., Vallance, B. A., Vázquez, A., Barba, J., Ibarra, J. A., O'Donnell, P. & other authors ( 2004; ). Dissecting virulence: systematic and functional analyses of a pathogenicity island. Proc Natl Acad Sci U S A 101, 3597–3602.[CrossRef]
    [Google Scholar]
  18. de Sablet, T., Bertin, Y., Vareille, M., Girardeau, J. P., Garrivier, A., Gobert, A. P. & Martin, C. ( 2008; ). Differential expression of stx2 variants in Shiga toxin-producing Escherichia coli belonging to seropathotypes A and C. Microbiology 154, 176–186.[CrossRef]
    [Google Scholar]
  19. Dibb-Fuller, M. P., Allen-Vercoe, E., Thorns, C. J. & Woodward, M. J. ( 1999; ). Fimbriae- and flagella-mediated association with and invasion of cultured epithelial cells by Salmonella enteritidis. Microbiology 145, 1023–1031.[CrossRef]
    [Google Scholar]
  20. Dibb-Fuller, M. P., Best, A., Stagg, D. A., Cooley, W. A. & Woodward, M. J. ( 2001; ). An in-vitro model for studying the interaction of Escherichia coli O157 : H7 and other enteropathogens with bovine primary cell cultures. J Med Microbiol 50, 759–769.
    [Google Scholar]
  21. Dogan, B., Klaessig, S., Rishniw, M., Almeida, R. A., Oliver, S. P., Simpson, K. & Schukken, Y. H. ( 2006; ). Adherent and invasive Escherichia coli are associated with persistent bovine mastitis. Vet Microbiol 116, 270–282.[CrossRef]
    [Google Scholar]
  22. Dopfer, D., Almeida, R. A., Lam, T. J., Nederbragt, H., Oliver, S. P. & Gaastra, W. ( 2000; ). Adhesion and invasion of Escherichia coli from single and recurrent clinical cases of bovine mastitis in vitro. Vet Microbiol 74, 331–343.[CrossRef]
    [Google Scholar]
  23. Dowd, S. E. & Williams, J. B. ( 2008; ). Comparison of Shiga-like toxin II expression between two genetically diverse lineages of Escherichia coli O157 : H7. J Food Prot 71, 1673–1678.
    [Google Scholar]
  24. Eaton, K. A., Friedman, D. I., Francis, G. J., Tyler, J. S., Young, V. B., Haeger, J., Abu-Ali, G. & Whittam, T. S. ( 2008; ). Pathogenesis of renal disease due to enterohemorrhagic Escherichia coli in germ-free mice. Infect Immun 76, 3054–3063.[CrossRef]
    [Google Scholar]
  25. Ethelberg, S., Olsen, K. E., Scheutz, F., Jensen, C., Schiellerup, P., Enberg, J., Petersen, A. M., Olesen, B., Gerner-Smidt, P. & Mølbak, K. ( 2004; ). Virulence factors for hemolytic uremic syndrome, Denmark. Emerg Infect Dis 10, 842–847.[CrossRef]
    [Google Scholar]
  26. Fukushima, H., Hashizume, T., Morita, Y., Tanaka, J., Azuma, K., Mizumoto, Y., Kaneno, M., Matsuura, M., Konma, K. & Kitani, T. ( 1999; ). Clinical experiences in Sakai City Hospital during the massive outbreak of enterohemorrhagic Escherichia coli O157 infections in Sakai City, 1996. Pediatr Int 41, 213–217.[CrossRef]
    [Google Scholar]
  27. Garmendia, J. & Frankel, G. ( 2005; ). Operon structure and gene expression of the espJtccP locus of enterohaemorrhagic Escherichia coli O157 : H7. FEMS Microbiol Lett 247, 137–145.[CrossRef]
    [Google Scholar]
  28. Garmendia, J., Frankel, G. & Crepin, V. F. ( 2005; ). Enteropathogenic and enterohemorrhagic Escherichia coli infections: translocation, translocation, translocation. Infect Immun 73, 2573–2585.[CrossRef]
    [Google Scholar]
  29. Giron, J. A., Torres, A. G., Freer, E. & Kaper, J. B. ( 2002; ). The flagella of enteropathogenic Escherichia coli mediate adherence to epithelial cells. Mol Microbiol 44, 361–379.[CrossRef]
    [Google Scholar]
  30. Grys, T. E., Siegel, M. B., Lathem, W. W. & Welch, R. A. ( 2005; ). The StcE protease contributes to intimate adherence of enterohemorrhagic Escherichia coli O157 : H7 to host cells. Infect Immun 73, 1295–1303.[CrossRef]
    [Google Scholar]
  31. Gyles, C. L. ( 2007; ). Shiga toxin-producing Escherichia coli: an overview. J Anim Sci 85, E45–E62.[CrossRef]
    [Google Scholar]
  32. Haack, K. R., Robinson, C. L., Miller, K. J., Fowlkes, J. W. & Mellies, J. L. ( 2003; ). Interaction of Ler at the LEE5 (tir) operon of enteropathogenic Escherichia coli. Infect Immun 71, 384–392.[CrossRef]
    [Google Scholar]
  33. Hauf, N. & Chakraborty, T. ( 2003; ). Suppression of NF-kappa B activation and proinflammatory cytokine expression by Shiga toxin-producing Escherichia coli. J Immunol 170, 2074–2082.[CrossRef]
    [Google Scholar]
  34. Hayashi, T., Makino, K., Ohnishi, M., Kurokawa, K., Ishii, K., Yokoyama, K., Han, C. G., Ohtsubo, E., Nakayama, K. & other authors ( 2001; ). Complete genome sequence of enterohemorrhagic Escherichia coli O157 : H7 and genomic comparison with a laboratory strain K-12. DNA Res 8, 11–22.[CrossRef]
    [Google Scholar]
  35. Higami, S., Nishimoto, K., Kawamura, T., Tsuruhara, T., Isshiki, G. & Ookita, A. ( 1998; ). Retrospective analysis of the relationship between HUS incidence and antibiotics among patients with Escherichia coli O157 enterocolitis in the Sakai outbreak. Kansenshogaku Zasshi 72, 266–272.[CrossRef]
    [Google Scholar]
  36. Ho, T. D., Davis, B. M., Ritchie, J. M. & Waldor, M. K. ( 2008; ). Type 2 secretion promotes enterohemorrhagic Escherichia coli adherence and intestinal colonization. Infect Immun 76, 1858–1865.[CrossRef]
    [Google Scholar]
  37. Hughes, T. R., Marton, M. J., Jones, A. R., Roberts, C. J., Stoughton, R., Armour, C. D., Bennett, H. A., Coffey, E., Dai, H. & other authors ( 2000; ). Functional discovery via a compendium of expression profiles. Cell 102, 109–126.[CrossRef]
    [Google Scholar]
  38. Huynh, H. T., Robitaille, G. & Turner, J. D. ( 1991; ). Establishment of bovine mammary epithelial cells (MAC-T): an in vitro model for bovine lactation. Exp Cell Res 197, 191–199.[CrossRef]
    [Google Scholar]
  39. Ikeda, K., Ida, O., Kimoto, K., Takatorige, T., Nakanishi, N. & Tatara, K. ( 1999; ). Effect of early fosfomycin treatment on prevention of hemolytic uremic syndrome accompanying Escherichia coli O157 : H7 infection. Clin Nephrol 52, 357–362.
    [Google Scholar]
  40. Iyoda, S., Koizumi, N., Satou, H., Lu, Y., Saitoh, T., Ohnishi, M. & Watanabe, H. ( 2006; ). The GrlR-GrlA regulatory system coordinately controls the expression of flagellar and LEE-encoded type III protein secretion systems in enterohemorrhagic Escherichia coli. J Bacteriol 188, 5682–5692.[CrossRef]
    [Google Scholar]
  41. Jandu, N., Ho, N. K., Donato, K. A., Karmali, M. A., Mascarenhas, M., Duffy, S. P., Tailor, C. & Sherman, P. M. ( 2009; ). Enterohemorrhagic Escherichia coli O157 : H7 gene expression profiling in response to growth in the presence of host epithelia. PLoS One 4, e4889 [CrossRef]
    [Google Scholar]
  42. Kailasan Vanaja, S., Bergholz, T. M. & Whittam, T. S. ( 2009; ). Characterization of the Escherichia coli O157 : H7 Sakai GadE regulon. J Bacteriol 191, 1868–1877.[CrossRef]
    [Google Scholar]
  43. Kaper, J. B., Nataro, J. P. & Mobley, H. L. ( 2004; ). Pathogenic Escherichia coli. Nat Rev Microbiol 2, 123–140.[CrossRef]
    [Google Scholar]
  44. Kerr, M. K. ( 2003; ). Linear models for microarray data analysis: hidden similarities and differences. J Comput Biol 10, 891–901.[CrossRef]
    [Google Scholar]
  45. Kim, Y., Oh, S., Park, S. & Kim, S. H. ( 2009; ). Interactive transcriptome analysis of enterohemorrhagic Escherichia coli (EHEC) O157 : H7 and intestinal epithelial HT-29 cells after bacterial attachment. Int J Food Microbiol 131, 224–232.[CrossRef]
    [Google Scholar]
  46. Knutton, S., Baldwin, T., Williams, P. H. & McNeish, A. S. ( 1989; ). Actin accumulation at sites of bacterial adhesion to tissue culture cells: basis of a new diagnostic test for enteropathogenic and enterohemorrhagic Escherichia coli. Infect Immun 57, 1290–1298.
    [Google Scholar]
  47. Kulasekara, B. R., Jacobs, M., Zhou, Y., Wu, Z., Sims, E., Saenphimmachak, C., Rohmer, L., Ritchie, J. M., Radey, M. & other authors ( 2009; ). Analysis of the genome of the Escherichia coli O157 : H7 2006 spinach-associated outbreak isolate indicates candidate genes that may enhance virulence. Infect Immun 77, 3713–3721.[CrossRef]
    [Google Scholar]
  48. Laing, C. R., Buchanan, C., Taboada, E. N., Zhang, Y., Karmali, M. A., Thomas, J. E. & Gannon, V. P. ( 2009; ). In silico genomic analyses reveal three distinct lineages of Escherichia coli O157 : H7, one of which is associated with hyper-virulence. BMC Genomics 10, 287 [CrossRef]
    [Google Scholar]
  49. Lathem, W. W., Grys, T. E., Witowski, S. E., Torres, A. G., Kaper, J. B., Tarr, P. I. & Welch, R. A. ( 2002; ). StcE, a metalloprotease secreted by Escherichia coli O157 : H7, specifically cleaves C1 esterase inhibitor. Mol Microbiol 45, 277–288.[CrossRef]
    [Google Scholar]
  50. Leopold, S. R., Magrini, V., Holt, N. J., Shaikh, N., Mardis, E. R., Cagno, J., Ogura, Y., Iguchi, A., Hayashi, T. & other authors ( 2009; ). A precise reconstruction of the emergence and constrained radiations of Escherichia coli O157 portrayed by backbone concatenomic analysis. Proc Natl Acad Sci U S A 106, 8713–8718.[CrossRef]
    [Google Scholar]
  51. Manning, S. D., Motiwala, A. S., Springman, A. C., Qi, W., Lacher, D. W., Ouellette, L. M., Mladonicky, J. M., Somsel, P., Rudrik, J. T. & other authors ( 2008; ). Variation in virulence among clades of Escherichia coli O157 : H7 associated with disease outbreaks. Proc Natl Acad Sci U S A 105, 4868–4873.[CrossRef]
    [Google Scholar]
  52. Matthews, K. R., Murdough, P. A. & Bramley, A. J. ( 1997; ). Invasion of bovine epithelial cells by verocytotoxin-producing Escherichia coli O157 : H7. J Appl Microbiol 82, 197–203.[CrossRef]
    [Google Scholar]
  53. McDaniel, T. K., Jarvis, K. G., Donnenberg, M. S. & Kaper, J. B. ( 1995; ). A genetic locus of enterocyte effacement conserved among diverse enterobacterial pathogens. Proc Natl Acad Sci U S A 92, 1664–1668.[CrossRef]
    [Google Scholar]
  54. Mead, P. S., Slutsker, L., Dietz, V., McCaig, L. F., Bresee, J. S., Shapiro, C., Griffin, P. M. & Tauxe, R. V. ( 1999; ). Food-related illness and death in the United States. Emerg Infect Dis 5, 607–625.[CrossRef]
    [Google Scholar]
  55. Michino, H., Araki, K., Minami, S., Takaya, S., Sakai, N., Miyazaki, M., Ono, A. & Yanagawa, H. ( 1999; ). Massive outbreak of Escherichia coli O157 : H7 infection in schoolchildren in Sakai City, Japan, associated with consumption of white radish sprouts. Am J Epidemiol 150, 787–796.[CrossRef]
    [Google Scholar]
  56. Naylor, S. W., Roe, A. J., Nart, P., Spears, K., Smith, D. G., Low, J. C. & Gally, D. L. ( 2005; ). Escherichia coli O157 : H7 forms attaching and effacing lesions at the terminal rectum of cattle and colonization requires the LEE4 operon. Microbiology 151, 2773–2781.[CrossRef]
    [Google Scholar]
  57. Nougayrede, J. P., Fernandes, P. J. & Donnenberg, M. S. ( 2003; ). Adhesion of enteropathogenic Escherichia coli to host cells. Cell Microbiol 5, 359–372.[CrossRef]
    [Google Scholar]
  58. Pallen, M. J., Beatson, S. A. & Bailey, C. M. ( 2005; ). Bioinformatics analysis of the locus for enterocyte effacement provides novel insights into type-III secretion. BMC Microbiol 5, 9 [CrossRef]
    [Google Scholar]
  59. Paton, J. C. & Paton, A. W. ( 1998; ). Pathogenesis and diagnosis of Shiga toxin-producing Escherichia coli infections. Clin Microbiol Rev 11, 450–479.
    [Google Scholar]
  60. Perna, N. T., Plunkett, G., III, Burland, V., Mau, B., Glasner, J. D., Rose, D. J., Mayhew, G. F., Evans, P. S., Gregor, J. & other authors ( 2001; ). Genome sequence of enterohaemorrhagic Escherichia coli O157 : H7. Nature 409, 529–533.[CrossRef]
    [Google Scholar]
  61. Pfaffl, M. W. ( 2001; ). A new mathematical model for relative quantification in real-time RT-PCR. Nucleic Acids Res 29, e45 [CrossRef]
    [Google Scholar]
  62. Quackenbush, J. ( 2002; ). Microarray data normalization and transformation. Nat Genet 32 (Suppl), 496–501.[CrossRef]
    [Google Scholar]
  63. R Development Core Team ( 2005; ). R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing.
  64. Riley, L. W., Remis, R. S., Helgerson, S. D., McGee, H. B., Wells, J. G., Davis, B. R., Hebert, R. J., Olcott, E. S., Johnson, L. M. & other authors ( 1983; ). Hemorrhagic colitis associated with a rare Escherichia coli serotype. N Engl J Med 308, 681–685.[CrossRef]
    [Google Scholar]
  65. Russell, R. M., Sharp, F. C., Rasko, D. A. & Sperandio, V. ( 2007; ). QseA and GrlR/GrlA regulation of the locus of enterocyte effacement genes in enterohemorrhagic Escherichia coli. J Bacteriol 189, 5387–5392.[CrossRef]
    [Google Scholar]
  66. Sandkvist, M. ( 2001; ). Type II secretion and pathogenesis. Infect Immun 69, 3523–3535.[CrossRef]
    [Google Scholar]
  67. Shariff, M., Bhan, M. K., Knutton, S., Das, B. K., Saini, S. & Kumar, R. ( 1993; ). Evaluation of the fluorescence actin staining test for detection of enteropathogenic Escherichia coli. J Clin Microbiol 31, 386–389.
    [Google Scholar]
  68. Spears, K. J., Roe, A. J. & Gally, D. L. ( 2006; ). A comparison of enteropathogenic and enterohaemorrhagic Escherichia coli pathogenesis. FEMS Microbiol Lett 255, 187–202.[CrossRef]
    [Google Scholar]
  69. Stevens, M. P. & Wallis, T. S. ( 2005; ). Adhesins of enterohemorrhagic Escherichia coli. In EcoSal – Escherichia coli and Salmonella: Cellular and Molecular Biology, Chapter 8.3.2.4. Edited by R. C. I. A. Böck, J. B. Kaper, F. C. Neidhardt, T. Nyström, K. E. Rudd, & C. L. Squires. Washington, DC: American Society for Microbiology.
  70. Strauch, E., Hammerl, J. A., Konietzny, A., Schneiker-Bekel, S., Arnold, W., Goesmann, A., Puhler, A. & Beutin, L. ( 2008; ). Bacteriophage 2851 is a prototype phage for dissemination of the Shiga toxin variant gene 2c in Escherichia coli O157 : H7. Infect Immun 76, 5466–5477.[CrossRef]
    [Google Scholar]
  71. Tarr, P. I., Gordon, C. A. & Chandler, W. L. ( 2005; ). Shiga-toxin-producing Escherichia coli and haemolytic uraemic syndrome. Lancet 365, 1073–1086.
    [Google Scholar]
  72. Tasara, T. & Stephan, R. ( 2007; ). Evaluation of housekeeping genes in Listeria monocytogenes as potential internal control references for normalizing mRNA expression levels in stress adaptation models using real-time PCR. FEMS Microbiol Lett 269, 265–272.[CrossRef]
    [Google Scholar]
  73. Tesh, V. L., Burris, J. A., Owens, J. W., Gordon, V. M., Wadolkowski, E. A., O'Brien, A. D. & Samuel, J. E. ( 1993; ). Comparison of the relative toxicities of Shiga-like toxins type I and type II for mice. Infect Immun 61, 3392–3402.
    [Google Scholar]
  74. Tobe, T., Beatson, S. A., Taniguchi, H., Abe, H., Bailey, C. M., Fivian, A., Younis, R., Matthews, S., Marches, O. & other authors ( 2006; ). An extensive repertoire of type III secretion effectors in Escherichia coli O157 and the role of lambdoid phages in their dissemination. Proc Natl Acad Sci U S A 103, 14941–14946.[CrossRef]
    [Google Scholar]
  75. Wagner, P. L., Neely, M. N., Zhang, X., Acheson, D. W., Waldor, M. K. & Friedman, D. I. ( 2001; ). Role for a phage promoter in Shiga toxin 2 expression from a pathogenic Escherichia coli strain. J Bacteriol 183, 2081–2085.[CrossRef]
    [Google Scholar]
  76. Yona-Nadler, C., Umanski, T., Aizawa, S., Friedberg, D. & Rosenshine, I. ( 2003; ). Integration host factor (IHF) mediates repression of flagella in enteropathogenic and enterohaemorrhagic Escherichia coli. Microbiology 149, 877–884.[CrossRef]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/mic.0.033126-0
Loading
/content/journal/micro/10.1099/mic.0.033126-0
Loading

Data & Media loading...

Supplements

Average growth of O157:H7 TW14359 and Sakai, in MOPS and DMEM. Increase in cell density of O157:H7 cultures in MOPS and DMEM was determined with optical density readings (OD ), which were ln transformed and plotted on the axis. Error bars represent the standard deviation of three independent culture replicates. [ PDF] (33 kb) Primer sequences and annealing temperatures used for qRT-PCR [ PDF] (10 kb) Invasion of MAC-T cells by O157:H7 strains TW14359 and Sakai. Invasion was quantified by standard plate counts of recovered bacteria. Error bars indicate standard deviation of the average number of c.f.u. ml recovered from three wells. Each plot represents an independent experiment. [ PDF] (38 kb) Expression ratios of 914 genes that were found to be significantly differentially expressed between strains TW14359 and Sakai. In the rightmost column, headed 'fold change (TW14359/Sakai)', positive values indicate upregulation in TW1439. [ Excel file] (155 kb)

PDF

Average growth of O157:H7 TW14359 and Sakai, in MOPS and DMEM. Increase in cell density of O157:H7 cultures in MOPS and DMEM was determined with optical density readings (OD ), which were ln transformed and plotted on the axis. Error bars represent the standard deviation of three independent culture replicates. [ PDF] (33 kb) Primer sequences and annealing temperatures used for qRT-PCR [ PDF] (10 kb) Invasion of MAC-T cells by O157:H7 strains TW14359 and Sakai. Invasion was quantified by standard plate counts of recovered bacteria. Error bars indicate standard deviation of the average number of c.f.u. ml recovered from three wells. Each plot represents an independent experiment. [ PDF] (38 kb) Expression ratios of 914 genes that were found to be significantly differentially expressed between strains TW14359 and Sakai. In the rightmost column, headed 'fold change (TW14359/Sakai)', positive values indicate upregulation in TW1439. [ Excel file] (155 kb)

PDF

Average growth of O157:H7 TW14359 and Sakai, in MOPS and DMEM. Increase in cell density of O157:H7 cultures in MOPS and DMEM was determined with optical density readings (OD ), which were ln transformed and plotted on the axis. Error bars represent the standard deviation of three independent culture replicates. [ PDF] (33 kb) Primer sequences and annealing temperatures used for qRT-PCR [ PDF] (10 kb) Invasion of MAC-T cells by O157:H7 strains TW14359 and Sakai. Invasion was quantified by standard plate counts of recovered bacteria. Error bars indicate standard deviation of the average number of c.f.u. ml recovered from three wells. Each plot represents an independent experiment. [ PDF] (38 kb) Expression ratios of 914 genes that were found to be significantly differentially expressed between strains TW14359 and Sakai. In the rightmost column, headed 'fold change (TW14359/Sakai)', positive values indicate upregulation in TW1439. [ Excel file] (155 kb)

PDF

Average growth of O157:H7 TW14359 and Sakai, in MOPS and DMEM. Increase in cell density of O157:H7 cultures in MOPS and DMEM was determined with optical density readings (OD ), which were ln transformed and plotted on the axis. Error bars represent the standard deviation of three independent culture replicates. [ PDF] (33 kb) Primer sequences and annealing temperatures used for qRT-PCR [ PDF] (10 kb) Invasion of MAC-T cells by O157:H7 strains TW14359 and Sakai. Invasion was quantified by standard plate counts of recovered bacteria. Error bars indicate standard deviation of the average number of c.f.u. ml recovered from three wells. Each plot represents an independent experiment. [ PDF] (38 kb) Expression ratios of 914 genes that were found to be significantly differentially expressed between strains TW14359 and Sakai. In the rightmost column, headed 'fold change (TW14359/Sakai)', positive values indicate upregulation in TW1439. [ Excel file] (155 kb)

EXCEL
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error