Differential expression of virulence-related genes in A Salmonella enterica serotype typhimurium luxS mutant in response to autoinducer AI-2 and poultry meat-derived AI-2 inhibitor.
Bacterial cells communicate with each other and respond to external stimuli using signal molecules called autoinducers (AIs). Poultry meat contains inhibitors that apparently interfere with AI-2 signaling. Our objective was to understand the expression of Salmonella Typhimurium genes (using spotted microarrays) in response to AI-2 in the presence, and absence, of poultry meat (PM) derived AI-2 inhibitors. Expression of 1136 virulence-related genes in Salmonella Typhimurium wildtype and its isogenic luxS mutant strain (unable to produce AI-2) was monitored when the cells were exposed for 3 hours to different treatments containing in vitro synthesized AI-2 and a PM inhibitor (AI-2, AI-2 + PM, or PM alone). The responses of the genes were unique in the presence of in vitro synthesized AI-2. Of 1136 genes on the array, 23 genes were differentially expressed (either upregulated or downregulated) at least 1.5-fold (P < 0.05) in the presence of AI-2. Exposure to the PM inhibitor resulted in 36 genes being differentially expressed, while the combined AI-2 + PM treatment resulted in 22 genes being differentially expressed, of which only 7 genes showed overlap with the PM treatment, suggesting a unique response when AI-2 interacts with the inhibitor molecules. The results suggest that Salmonella gene expression can vary depending on the presence or absence of the poultry meat matrix and/or AI-2 molecules. Understanding the interaction of AI-2 and inhibitors of AI-2 activity found in poultry meat can help explain Salmonella survival and virulence on poultry products.
Widmer
Kenneth W
KW
Food Safety and Environmental Microbiology Program, Departments of Poultry Science and Nutrition & Food Science, Texas A&M University, College Station, TX 77843, USA.
Jesudhasan
Palmy R
PR
Dowd
Scot E
SE
Pillai
Suresh D
SD
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism; D002645:Chickens; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors; D006801:Humans; D007783:Lactones / Q000037:antagonists & inhibitors*; D008460:Meat / Q000382:microbiology*; D046228:Microarray Analysis; D009154:Mutation; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D015398:Signal Transduction; D014158:Transcription, Genetic; D037521:Virulence Factors / Q000235:genetics*
D001426:Bacterial Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D037521:Virulence Factors; D006714:Homoserine; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria