Acyl-homoserine lactones (AHLs) are signaling molecules used by many bacteria for communication, a process known as quorum sensing. These molecules allow bacteria to coordinate their behavior based on population density, enabling them to regulate activities such as biofilm formation, virulence, and bioluminescence. AHLs are characterized by a homoserine lactone ring and an acyl side chain, which can vary in length and structure. This diversity allows different bacterial species to produce unique AHLs, facilitating specific interactions. AHLs play a crucial role in microbial ecology and can influence interactions with other organisms, including plants and animals.