N-heptanoyl-L-Homoserine lactone (C7-HSL) is a small diffusible signaling molecule involved in quorum sensing, thereby controlling gene expression and affecting cellular metabolism. Quorum sensing is a regulatory system used by bacteria for controlling gene expression in response to increasing cell density, and by quenching this system could lead to controlling bacterial infections. The expression of specific target genes, such as transcriptional regulators belonging to the LuxIR family of proteins, is coordinated by synthesis of diffusible acylhomoserine lactone (AHL) molecules. The diverse applications of this molecule include regulation of virulence, infection prevention, and septicemia in fish.