title: Expression of colonization factor antigen I fimbriae by enterotoxigenic Escherichia coli; influence of growth conditions and a recombinant positive regulatory gene.
abstract: Enterotoxigenic Escherichia coli (ETEC) may spontaneously lose the positive regulatory cfaR gene and thereby the capacity to express colonization factor antigen I (CFA/I). A recombinant plasmid harbouring the cfaR gene was transformed into cfaR-negative mutant ETEC strains. CFA/I expression of wild-type and cfaR-transformed ETEC cultivated in different liquid media was quantified. At 37 degrees C, a high level of CFA/I expression from wild-type and cfaR-transformed strains was observed after growth in CFA broth. Transformation enhanced CFA/I expression only marginally. The transformant cultures showed a considerable variation in CFA/I expression which was paralleled by the proportion of individual bacteria producing CFA/I. This heterogeneity could be explained by a variable tendency to structural CFA/I gene loss among individual cfaR-transformed bacteria.
authors.affiliation: Center for International Health, Gade Institute, University of Bergen, Haukeland Hospital, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Halvorsen
authors.forename: H
authors.initials: H
authors.lastname: Valvatne
authors.forename: H M
authors.initials: HM
authors.lastname: Grewal
authors.forename: W
authors.initials: W
authors.lastname: Gaastra
authors.forename: H
authors.initials: H
authors.lastname: Sommerfelt
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D002648:Child; D003470:Culture Media; D003967:Diarrhea / Q000382:microbiology; D004768:Enterotoxins / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D004927:Escherichia coli Infections / Q000382:microbiology; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000502:physiology*; D005798:Genes, Bacterial; D005809:Genes, Regulator; D006801:Humans; D016296:Mutagenesis; D010957:Plasmids; D011995:Recombination, Genetic; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D004768:Enterotoxins; C022924:colonization factor antigens; D036781:Fimbriae Proteins