Mehrdad Moosazadeh Moghaddam, Samaneh Khodi and Ali Mirhosseini
Quorum sensing is a key behaviour-coordination mechanism employed by many bacteria to regulate gene expression in accordance with population density through the use of signal molecules, known as autoinducers. The quorum sensing is used by Bacteria populations to communicate and coordinate their group interactions, which is typically applied by pathogens in infection processes. Generally, the quorum sensing pathways in bacteria are composed of several main parts, including bacteria populations, signal molecules, protein activators and target genes. In this system, the bacteria secrete the signal molecules into the environment and the concentration increases gradually as the bacteria population grows. In a certain concentration threshold, the molecules become detectable to the bacteria populations, and then activate target genes that regulate various behaviours, such as virulence factors. In Pseudomonas aeruginosa, the expression of many virulence factors appears to be controlled by quorum sensing. So, according to the role of this mechanism in the regulation and production of many virulence factors, the function of quorum sensing is required for Pseudomonas aeruginosa to cause disease and infection. In this article, we discussed the quorum sensing mechanism in Gram negative and positive bacteria with a closer look at the Pseudomonas aeruginosa.