Question

The Auto Inducers-I (AIs) produced in bacterial quorum sensing (QS) are produced by

• A. Gram negative bacteria only
• B. Gram positive bacteria only
• C. Either Gram positive bacteria or Gram negative bacteria
• D. Gram variable bacteria

Hint:

AI-1 (AHLs) = Gram-negative bacteria only; Autoinducing peptides (AIP) = Gram-positive only; AI-2 (LuxS) = Universal (both).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Quorum sensing is a cell-density dependent chemical communication system in bacteria mediated by secreted autoinducer signaling molecules.

Step 2: Detailed Explanation:
The autoinducer signaling systems are distinct across bacterial classes:
1. Autoinducer-1 (AI-1): Acyl-homoserine lactones (AHLs), synthesized by LuxI-type synthases and recognized by LuxR-type receptors, produced exclusively by Gram-negative bacteria for intra-species communication.
2. Autoinducer peptides (AIPs): Oligopeptides utilized by Gram-positive bacteria.
3. Autoinducer-2 (AI-2): Furanosyl borate diester, synthesized by LuxS in both Gram-positive and Gram-negative bacteria for inter-species signaling.

Step 3: Final Answer:
Thus, Autoinducers-I (AI-1 AHLs) are produced by Gram negative bacteria only.