title: Regulation of virulence factors of enterohemorrhagic Escherichia coli O157:H7 by self-produced extracellular factors.
abstract: Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes serious diarrhea and hemolytic uremic syndrome in humans. The expressions of EspD and intimin by O157:H7 have now been shown to be down-regulated by medium conditioned by O157:H7 grown at stationary phase. Preparation of conditioned medium showing the effect on the amount of EspD was not dependent on temperature or growth medium, but was dependent on growth phase. Inhibition of EspD and intimin expression was also induced by medium conditioned by E. coli K-12 strains and homoserine lactone, a signal molecule of the quorum-sensing system in gram-negative bacteria. These results suggest the possibility that the quorum-sensing system mediated by self-produced extracellular factors plays an important role in control of colonization of EHEC O157:H7.
authors.affiliation: Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Japan. kanamaru@meijo-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Kanamaru
authors.forename: K
authors.initials: K
authors.lastname: Kanamaru
authors.forename: I
authors.initials: I
authors.lastname: Tatsuno
authors.forename: T
authors.initials: T
authors.lastname: Tobe
authors.forename: C
authors.initials: C
authors.lastname: Sasakawa
mesh_terms: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins; D003470:Culture Media / Q000494:pharmacology; D015536:Down-Regulation; D019453:Escherichia coli O157 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D029968:Escherichia coli Proteins; D015870:Gene Expression / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; C474481:EspD protein, E coli; D008565:Membrane Proteins; C073819:eaeA protein, E coli