Obacunone represses Salmonella pathogenicity islands 1 and 2 in an envZ-dependent fashion.
Appl Environ Microbiol, 2012/10;78(19):7012-22.
Vikram A[1], Jayaprakasha GK, Jesudhasan PR, Pillai SD, Patil BS
Affiliations
PMID: 22843534DOI: 10.1128/AEM.01326-12
Impact factor: 5.005
Abstract
Obacunone belongs to a class of unique triterpenoids called limonoids, present in Citrus species. Previous studies from our laboratory suggested that obacunone possesses antivirulence activity and demonstrates inhibition of cell-cell signaling in Vibrio harveyi and Escherichia coli O157:H7. The present work sought to determine the effect of obacunone on the food-borne pathogen Salmonella enterica serovar Typhimurium LT2 by using a cDNA microarray. Transcriptomic studies indicated that obacunone represses Salmonella pathogenicity island 1 (SPI1), the maltose transporter, and the hydrogenase operon. Furthermore, phenotypic data for the Caco-2 infection assay and maltose utilization were in agreement with microarray data suggesting repression of SPI1 and maltose transport. Further studies demonstrated that repression of SPI1 was plausibly mediated through hilA. Additionally, obacunone seems to repress SPI2 under SPI2-inducing conditions as well as in Caco-2 infection models. Furthermore, obacunone seems to repress hilA in an EnvZ-dependent fashion. Altogether, the results of the study seems to suggest that obacunone exerts an antivirulence effect on S. Typhimurium and may serve as a lead compound for development of antivirulence strategies for S. Typhimurium.
MeSH terms
Bacterial Proteins; Benzoxepins; Caco-2 Cells; Citrus; Epithelial Cells; Gene Expression Profiling; Genomic Islands; Humans; Limonins; Maltose; Microarray Analysis; Salmonella typhimurium; Virulence Factors
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