title: Identification of ground beef-derived fatty acid inhibitors of autoinducer-2-based cell signaling.
abstract: Autoinducer-2 (AI-2) molecules are used by several microorganisms to modulate various processes, including bioluminescence, biofilm formation, and virulence expression. Certain food matrices, including ground beef extracts, possess compounds capable of inhibiting AI-2 activity. In the present study, we identified and characterized these AI-2 inhibitors from ground beef extract using hexane solvent extraction and gas chromatography. Gas chromatographic analysis revealed the presence of several fatty acids such as palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:omega9), and linoleic acid (C18:omega6) that were capable of inhibiting AI-2 activity. These fatty acids were tested (using Vibrio harveyi BB170 and MM32 reporter strains) at different concentrations (1, 5, and 10 mM) to identify differences in the level of AI-2 activity inhibition. AI-2 inhibition ranged from 25 to 90%. A mixture of these fatty acids (prepared at concentrations equivalent to those present in the ground beef extract) produced 52 to 65% inhibition of AI-2 activity. The fatty acid mixture also negatively influenced Escherichia coli K-12 biofilm formation. These results demonstrate that both medium- and long-chain fatty acids in ground beef have the ability to interfere with AI-2-based cell signaling.
authors.affiliation: Food Safety & Environmental Microbiology Program, Department of Poultry Science, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Kamlesh A
authors.initials: KA
authors.lastname: Soni
authors.forename: Palmy
authors.initials: P
authors.lastname: Jesudhasan
authors.forename: Martha
authors.initials: M
authors.lastname: Cepeda
authors.forename: Kenneth
authors.initials: K
authors.lastname: Widmer
authors.forename: G K
authors.initials: GK
authors.lastname: Jayaprakasha
authors.forename: Bhimanagouda S
authors.initials: BS
authors.lastname: Patil
authors.forename: Michael E
authors.initials: ME
authors.lastname: Hume
authors.forename: Suresh D
authors.initials: SD
authors.lastname: Pillai
mesh_terms: D000818:Animals; D018441:Biofilms; D002417:Cattle; D048168:Escherichia coli K12 / Q000187:drug effects / Q000254:growth & development / Q000472:pathogenicity; D005227:Fatty Acids / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors; D006801:Humans; D007783:Lactones / Q000037:antagonists & inhibitors*; D008461:Meat Products / Q000032:analysis / Q000382:microbiology*; D053038:Quorum Sensing; D015398:Signal Transduction; D014733:Vibrio / Q000187:drug effects / Q000254:growth & development / Q000472:pathogenicity
chemical_list: D005227:Fatty Acids; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine