Book Description

The ability of bacteria to identify, sense, express and respond to their bacterial population density is known as “Quorum Sensing” (QS) or “Cell - to - Cell communication” which is mediated by autoinducer molecules (Fuqua et al., 1994). Autoinducers are chemical signaling molecules which takes responsibility to increase the bacterial cell population. The gene expression is altered by the accumulation of autoinducers and in turn it resulted in activation of virulence factors like biofilm formation (McLean et al., 1997), bioluminescence (Nealson 1977), swarming motility (Eberl et al., 1996), conjugation, antibiotic production, sporulation, pigment production etc (Gonzale et al., 2006). There are different types of signaling molecules produced by both gram positive and gram negative bacterial pathogens. The common signaling molecules are auto inducing peptides (AIPs), Acyl homoserine lactone (AHLs) and AI-2. Some other signaling molecules with less characterized had been detected in few bacteria such as diffusible signal factor AI-3, the cyclic dipeptides which appear to regulate virulence, biofilm formation and motility (Ryan et al., 2008).