Question

answer the following questions regarding quorum sensing.

1) Definition in case of bacterial cells

2) Its role in formation of biofilm and its significance in environmental engineering bioprocesses

3) What kind of signaling molecule of aerobic bacteria can you use to control the biofilms in an environmental engineering system and describe its control mechanism.

Answer 1

Ans .(1) Quorum sensing :- It is the ability to detect and to respond to cell population density by gene regulation. As one example, quorum sensing enables bacteria to restrict the expression of specific genes to the high cell densities at which the resulting phenotypes will be most beneficial.

Many bacteria are known to regulate their cooperative activities and physiological processes through a mechanism called Quorum sensing , in which bacterial cells communicate with each other by releasing , sensing and responding to small diffusible signal molecules.

Ans .(2) Quorum sensing upregulates the synthesis of surfactant molecules. Biofilm development and Quorum sensing are closely interconnected processes. Quorum sensing regulates gene involved in biofilm development. Biofilm formation is a cooperative group behavior that involves bacterial populations living embedded in a self produced extracellular matrix.

Biofilms are widely used in environmental engineering systems as the powerhouseof treatment processes.e.g. biofilms are used to remove organic matter in drinking water, a process called biofiltration.

Ans .(3) Fatty acid signal cis-2-decanoic acid (cis-DA) controls bioflims by 3 different mechanisms : by impairing biofilm formation, by inducing biofilm dispersion, and by modulating the persister cell sub-population.