A Caenorhabditis elegans model of Yersinia infection: biofilm formation on a biotic surface.
To investigate Yersinia pathogenicity and the evolutionary divergence of the genus, the effect of pathogenic yersiniae on the model organism Caenorhabditis elegans was studied. Three strains of Yersinia pestis, including a strain lacking pMT1, caused blockage and death of C. elegans; one strain, lacking the haemin storage (hms) locus, caused no effect. Similarly, 15 strains of Yersinia enterocolitica caused no effect. Strains of Yersinia pseudotuberculosis showed different levels of pathogenicity. The majority of strains (76 %) caused no discernible effect; 5 % caused a weak infection, 9.5 % an intermediate infection, and 9.5 % a severe infection. There was no consistent relationship between serotype and severity of infection; nor was there any relationship between strains causing infection of C. elegans and those able to form a biofilm on an abiotic surface. Electron microscope and cytochemical examination of infected worms indicated that the infection phenotype is a result of biofilm formation on the head of the worm. Seven transposon mutants of Y. pseudotuberculosis strain YPIII pIB1 were completely or partially attenuated; mutated genes included genes encoding proteins involved in haemin storage and lipopolysaccharide biosynthesis. A screen of 15 defined C. elegans mutants identified four where mutation caused (complete) resistance to infection by Y. pseudotuberculosis YPIII pIB1. These mutants, srf-2, srf-3, srf-5 and the dauer pathway gene daf-1, also exhibit altered binding of lectins to the nematode surface. This suggests that biofilm formation on a biotic surface is an interactive process involving both bacterial and invertebrate control mechanisms.
London School of Hygiene and Tropical Medicine, Dept Infectious and Tropical Diseases, Keppel St, London WC1E 7HT, UK.
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GWP
Joshua
London School of Hygiene and Tropical Medicine, Dept Infectious and Tropical Diseases, Keppel St, London WC1E 7HT, UK.
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AV
Karlyshev
DSTL, Porton Down, Salisbury SP4 0JQ, UK.
M P
MP
Smith
DSTL, Porton Down, Salisbury SP4 0JQ, UK.
K E
KE
Isherwood
DSTL, Porton Down, Salisbury SP4 0JQ, UK.|London School of Hygiene and Tropical Medicine, Dept Infectious and Tropical Diseases, Keppel St, London WC1E 7HT, UK.
R W
RW
Titball
London School of Hygiene and Tropical Medicine, Dept Infectious and Tropical Diseases, Keppel St, London WC1E 7HT, UK.
B W
BW
Wren
D000818:Animals; D001483:Base Sequence; D018441:Biofilms; D017173:Caenorhabditis elegans / Q000382:microbiology*; D017931:DNA Primers; D004195:Disease Models, Animal; D014644:Genetic Variation; D016133:Polymerase Chain Reaction; D014774:Virulence / Q000235:genetics; D015011:Yersinia pseudotuberculosis / Q000166:cytology / Q000235:genetics / Q000472:pathogenicity*; D015012:Yersinia pseudotuberculosis Infections / Q000503:physiopathology*
D017931:DNA Primers