AI-2 was first discovered in the light producing system of the bacteria
homoserine lactone signaling molecule. However the bacteria were also found to recognize a second auto inducer AI-2.[3] Scientist also found that V. harveyi luminescence could be induced by 75 other bacterial species AI-2 molecules.[4][5]
This discovery led to the proposal of AI-2 as a universal form of communication between bacteria species. In addition to information about cell densities AI-2 can provide information on the
The enzyme LuxS is responsible for AI-2 synthesis.
V. cholerae, and Enterococcus faecalis providing further evidence that this molecule may be a universal signal among bacteria.[4]
Shigella flexneri use AI-2 to mediate
gut flora effect the production of AI-2 in Shigella and its subsequent virulence.[1]
AI-2 is required for the biofilm formation in P. ginivalis and S. gordonii. S. gordonii is a major cause of dental plaque and its adherence is essential for many other pathogenic bacteria to also adhere to teeth. P. ginivalis causes periodontal disease. If neither bacteria possess a functional copy of the LuxS gene they cannot form a biofilm. However, if either one of the bacteria has the LuxS gene they can form biofilms suggesting again this molecule is used for communication between unrelated species.[2]
eukaryotes it is a good potential target for antibiotics. Also AI-2 signaling seems to control many virulence factors in bacteria so blocking this signal could lead to new ways to control bacterial infections such as cholera.[7]
Since the AI-2 molecule seems to be involved in the virulence cascade if we could block the uptake of AI-2 then we could potentially stop the virulence cascade.
Fungi also communicate with one another. Quorum-sensing molecules (QSMs) from fungi include farnesol, tyrosol, phenylethanol, and tryptophol. QSMs have been studied in Candida albicans, C. dubliniensis, Aspergillus niger, A. nidulans, and Fusarium graminearum. QSMs can include morphogenesis, germination, apotopsis, pathogenicity, and biofilm structures.[8]
