Effects of global regulatory proteins and environmental conditions on fimbrial gene expression of F165(1) and F165(2) produced by Escherichia coli causing septicaemia in pigs.
Escherichia coli O115:F165 strains are associated with septicaemia in young pigs and possess at least two types of fimbriae. F165(1) fimbriae belong to the P fimbrial family and F165(2) fimbriae belong to the S fimbrial family. Regulatory regions of foo (F165(1)) and fot (F165(2)) fimbrial gene clusters from wild-type strain 4787 were sequenced and characterised. Expression of F165(1) and F165(2) fimbrial genes was analysed by using lacZ and/or luxAB as reporter genes under the control of the native fimbrial promoters. Differential expression of fimbrial genes was observed. Global regulatory mechanisms such as catabolite repression, leucine-responsive regulatory protein (Lrp), methylation and DNA supercoiling were demonstrated to influence foo and fot expression. foo and fot expression was optimal at 37 degrees C and under aerobic conditions. Expression of foo was higher on minimal medium, whereas fot expression was higher on complex Luria-Bertani medium. This could reflect an in vivo differential expression.
Daigle
F
F
Department of Pathology and Microbiology, University of Montreal, St. Hyacinthe, Québec, Canada.
Forget
C
C
Martin
C
C
Drolet
M
M
Tessier
M C
MC
Dezfulian
H
H
Harel
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial; D016470:Bacteremia / Q000382:microbiology / Q000662:veterinary; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004278:DNA, Superhelical; D004926:Escherichia coli / Q000235:genetics* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology; D014774:Virulence
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004278:DNA, Superhelical; D029968:Escherichia coli Proteins; C088773:F165 protein, E coli; D036781:Fimbriae Proteins; C092731:F165-2 fimbrial antigen, E coli