(9; Scheme 2) and a previously unid

(9; Scheme 2) and a previously unidentified furanone
boronate diester that appears to be a universal signal (10;
Scheme 2), from Vibrio fisheri being examples. These
compounds signal the activation of genes promoting virulence,
spore formation, biofilm formation, and other
phenomena.21,22 Very recently, another variation on interruption
of Gram-negative aggregates by Gram-positive
nontoxic secondary metabolites (phenylethylamides 11 and
12; Scheme 2), by interfering with quorum-sensing, was
reported by Teasdale et al.23 This is the first time that such
compounds had been identified. In addition to such actions,
microbes can also produce simple molecules that will
disperse biofilms, as demonstrated by Davies and Marques
in late 2008 when they demonstrated that the pseudomonad
metabolite cis-2-decenoic acid was a nanomolar disrupter
of cross-kingdom biofilms.24 In addition to simple signaling
in normal settings in soils, quorum-sensing may also be one
of the causes of significant infection in long-term patients
due to the recruitment of many different microbes and the
subsequent production of resistant biofilms on in-dwelling
catheters and prosthetic devices.