Autoinducer 2: a concentration-dependent signal for mutualistic bacterial biofilm growth

摘要: Summary 4,5-dihydroxy-2,3-pentanedione (DPD), a product of the LuxS enzyme in catabolism S -ribosylho- mocysteine, spontaneously cyclizes to form autoin- ducer 2 (AI-2). AI-2 is proposed be universal signal molecule mediating interspecies communi- cation among bacteria. We show that mutualistic and abundant biofilm growth flowing saliva two human oral commensal bacteria, Actinomyces naeslundii T14V Streptococcus oralis 34, dependent upon production by S. 34. A luxS mutant 34 was constructed which did not produce AI-2. Unlike wild-type dual-species bio- films, A. an exhibit mutualism generated only sparse biofilms contained 10-fold lower mass each species. Restoration levels genetic or chemical (synthetic DPD) complementation re-established high biomass characteristic for wild- type biofilm. Furthermore, optimal concentration DPD determined, above below formation suppressed. The 100-fold than detection limit currently accepted assay. Thus, acts as its con- centration critical between spe- cies bacteria grown under conditions are representative cavity.