Isolation and characterization of conditional adherent and non-type 1 fimbriated Salmonella typhimurium mutants.
Mutations in the genes encoding the type 1 fimbriae of Salmonella typhimurium were isolated by selecting for the deletion of Tn10 inserted adjacent to the chromosomal fim+ genes and screening for the loss of mannose-sensitive haemagglutination (HA) activity. S. typhimurium strains with Tn10 insertions in ahp were hypersensitive to peroxides, and tetracycline-sensitive derivatives of ahp::Tn10 mutants displayed two fim mutant phenotypes. The predominant class of fim mutants did not synthesize type 1 fimbriae. A second type of fim mutant synthesized type 1 fimbriae and exhibited a conditional lipoic acid requirement for HA. A fim-lip conditional mutant synthesized type 1 fimbriae when grown in Mueller-Hinton broth but the haemagglutinating activity of the fimbriae was dependent upon the addition of lipoic acid to the growth medium. Independently isolated lip mutations did not demonstrate a similar pleiotropic effect on HA. Western blots of fimbriae extracted from a fim-lip conditional mutant that was grown under permissive and restrictive conditions indicated the presence of 33 and 36.6 kDa proteins in HA+ fimbriae that were absent in HA- fimbriae. The HA+ phenotype of both conditional and non-fimbriated mutants was restored by transformation with cloned genes encoding S. typhimurium type 1 fimbriae.
Department of Biology, Washington University, St Louis, Missouri 63130-4899.
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Lockman
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Curtiss
D001422:Bacterial Adhesion / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D015139:Blotting, Southern; D015153:Blotting, Western; D010861:Fimbriae, Bacterial / Q000502:physiology; D005816:Genetic Complementation Test; D006386:Hemagglutination Tests; D008854:Microscopy, Electron; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics; D010544:Peroxidases; D054464:Peroxiredoxins; D012486:Salmonella typhimurium / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification / Q000648:ultrastructure; D008063:Thioctic Acid / Q000378:metabolism
D001426:Bacterial Proteins; D008063:Thioctic Acid; D010088:Oxidoreductases; D010544:Peroxidases; D054464:Peroxiredoxins