Which statement best describes AI-2 and LuxS in oral biofilms?

Which statement best describes AI-2 and LuxS in oral biofilms?

• A. AI-2 is a universal quorum-sensing molecule; LuxS degrades AI-2, preventing communication.
• B. AI-2 is a host-derived hormone; LuxS is a receptor.
• C. AI-2 is a bacterial toxin; LuxS is a transporter.
• D. AI-2 is a universal quorum-sensing molecule; LuxS is the enzyme that produces AI-2, enabling interspecies communication in oral biofilms.

Answer: (D)

AI-2 acts as a universal bacterial communication signal, and LuxS is the enzyme that produces AI-2. In the activated methyl cycle, LuxS cleaves S-ribosylhomocysteine to yield homocysteine and a precursor that rapidly becomes AI-2 in solution. This AI-2 molecule can be detected by many different oral bacteria, enabling interspecies signaling within biofilms and helping coordinate collective behaviors like biofilm formation and metabolic interactions. AI-2 is not a host-derived hormone, and LuxS is not a receptor or a degradative protein, nor is AI-2 a toxin.

AI-2 acts as a universal bacterial communication signal, and LuxS is the enzyme that produces AI-2. In the activated methyl cycle, LuxS cleaves S-ribosylhomocysteine to yield homocysteine and a precursor that rapidly becomes AI-2 in solution. This AI-2 molecule can be detected by many different oral bacteria, enabling interspecies signaling within biofilms and helping coordinate collective behaviors like biofilm formation and metabolic interactions. AI-2 is not a host-derived hormone, and LuxS is not a receptor or a degradative protein, nor is AI-2 a toxin.