Microbial interactions are crucial for a successful establishment and maintenance of a microbial population. These interactions occur by the environmental recognition followed by exchange of molecular and genetic information that include many mechanisms and classes of molecules. These mechanisms allow microorganisms to establish in a community, which depending on the multi-trophic interaction resulting in high diversity. Microorganisms rarely occur as single species populations and are encountered in many hosts/environments, thus there is a large variety of types of microbial interactions concerning the organisms involved. Bacteria–bacteria, fungus–fungus, bacteria–fungus, fungus–plant/animal, bacteria–plant/animal and bacteria–fungus–plant/animal interactions, including parasitic, mutualistic interactions involve many interactive mechanisms.
Bacteria communicate with one another using chemical signal molecules. As in higher organisms, the information supplied by these molecules is critical for synchronizing the activities of large groups of cells. This process, termed quorum sensing, allows bacteria to monitor the environment for other bacteria and to alter behaviour on a population-wide scale in response to changes in the number and/or species present in a community.
Quorum sensing (QS) is the bacterial cell-cell communication. This process involves the production and detection of signalling molecules known as auto inducers allowing bacterial communities to express genes collectively.QS systems are different in Gram-negatives and Gram-positives, the signalling molecules are called acyl-homoserine-lactones (AHLs) and gamma-butyrolactones in Streptomyces and peptides in Gram positives.
The first QS system described was in the 1980s in Vibrio fischeri (formerly known as Photobacteriumfischeri) bacterium. In the sea, it is in a low population density and does not luminesce. Therefore, when it is in a symbiotic association with fishes and squids it luminesce.Quorum sensing is cell-to-cell communication in bacteria have ability to control development, sporulation, and antibiotic synthesis also virulence factor induction, cell differentiation, moreover nutrient flux along with extra physiological events in pathogenic bacterial infections.
Auto inducers are very useful as input signals as they are little, diffuse freely in aqueous media, and are simply taken up through cells. As the engineered cells synthesize QS signals by themselves, they are able to watch their own cell density with modulate their activities appropriately, thereby falling the need for outer protection.
Quorum sensing offers potential to create engineered bacteria capable of invading cancer cells. It is possible to create a novel anti-cancer therapeutics by the addition of cancer-destructing modules to these microbial biosensors.
Creation of transgenic plants that are able to defend themselves against common bacterial pathogens. It plays a main role in controlling a diversity of microbial cell activities, such as biofilm formation and virulence that considerably impact human health, agriculture, and commercial production and transport systems. Scientists now a days creating more possible benefits from quorum sensing and off course there is lots of potential development for advancement in 2011ranging from marine to human disorders.