Question

What is quorum sensing in bacteria

Answer 1

Quorum sensing is a method of gene expression regulation by which a bacterium communicates in response to the changes in local cell population density. Such bacteria that are involved in quorum sensing produces certain chemical signal molecules called auto inducers that leads to increase in concentration in terms of cell density .When concentration changes based on fluctuations in cell density populations, gene expressions also get altered.

Both Gram positive and gram negative bacterium are involved in quorum sensing thereby regulating various physiological activities like symbiosis, virulence, motility, antibiotic production, competence, sporulation, biofilm formation etc.

To communicate by quorum sensing, Gram negative bacterium use auto inducers like acylated homosysteine lactones and gram positive bacterium uses processed oligopeptides. These communications occurs within and between bacterial species. The bacteria coordinate gene expression with ability to communicate among groups based on nature of auto inducers, their signal relay mechanism and target genes involved in quorum sensing process and these factors decides the behavior of the entire community. It is evident that the evolution of quorum sensing process would have paved way for developments from prokaryotic nature to multicellularity.