Salmonella typhimurium neuraminidase acts with inversion of configuration.
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ABSTRACT:
SUBMITTER: Guo X
PROVIDER: S-EPMC1137691 | biostudies-other | 1993 Dec
REPOSITORIES: biostudies-other
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Project description:Salmonella enterica serovar Typhimurium produces type 1 fimbriae on the outer membrane and such hair-like appendages is proposed to play a significant role in the attachment of the bacteria to host cells and tissues. S. Typhimurium cultured in static broth favors expression of type 1 fimbriae. Conversely, solid agar medium represses type 1 fimbrial expression. Production of type 1 fimbriae is cooperatively regulated by fimZ, fimY, stm0551, fimW, and fimU within the fim gene cluster. FimZ belongs to the response regulator of the two-component regulatory system in bacteria and functions as a DNA binding protein. FimZ can bind to the promoter of the fimbrial major subunit gene fimA to activate its expression and produce type 1 fimbriae. A fimZ mutant in LB5010 strain constructed by allelic exchange was found to be non-fimbriate. Total RNA was extracted from the parental LB5010 and the fimZ mutant strain cultured in static broth and analyzed by hybridization to a S. Typhimurium LT2 DNA microarray. Transcriptomic analysis indicated that the stress response related gene cpxP, soxS and type 1 fimbriae related genes were down-regulated, whereas plasmid-encoded fimbriae, flagella associated genes and virulence genes like virK and mgtC were up-regulated in the fimZ mutant strain. It is possible that FimZ protein may play a role to interact with other genes besides fim genes. Mechanisms of this crosstalk warrant further elucidation.
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Project description:Fimbriae are hair-like structures present on the outer membrane of many Enterobacteriaceae and such appendages are proposed to play a significant role in the attachment of the bacteria to host cells and tissues. Salmonella enterica serovar Typhimurium has the potential to produce 13 different fimbrial types, among which type 1 fimbriae is the most common found. Expression of type 1 fimbriae is cooperatively controlled by fimZ, fimY, stm0551, fimW, and fimU within the fim gene cluster. FimZ belongs to the response regulator of the two-component regulatory system in bacteria and functions as a DNA binding protein. FimZ is a positive regulator for type 1 fimbrial expression in S. Typhimurium. A fimZ mutant in ATCC 14028 strain constructed by allelic exchange did not produce type 1 fimbriae. Total RNA was extracted from the parental ATCC 14028 and its fimZ mutant cultured in static broth and analyzed by hybridization to a S. Typhimurium LT2 DNA microarray. Transcriptomic analysis indicated that the type 1 fimbriae related genes, multidrug efflux protein gene acrF were down-regulated, whereas flagella associated genes, chemotaxis and virulence genes such as invF and invH genes were up-regulated in the fimZ mutant strain. It is possible that FimZ protein may play a role to interact with other genes besides regulating type 1 fimbriae.
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