Team:KAIT Japan/Project

Back Ground

Bacteria detect the concentration of its friends, called Quorum Sensing, and the sensing system is one of the communication tools between microbes. It is related also to formation of biofilm and to pathogenicity. As the Quorum Sensing of Gram-negative bacterias, Acyl-Homoserine Lactone ( AHL ) is released to recognize each other. 2007, the team of Chiba University made the vacteria production of aiia to decrease the AHL. We considered application of the system to make a colony layer on a colony layer by depressing of Quorum Sensing.

Purpose 　

We make bacteria that have transgene of AiiA, and get the bacteria to produce abundance of AiiA.The abundance of AiiA inhibit AHL,and General, colony and colony don’t approach by AHL. Our projects were done to approach and overlap.

Quorum Sensing

Quorum sensing is a system of stimulus and response correlated to population density. Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population. In similar fashion, some social insects use quorum sensing to determine where to nest.

AHL　and AiiA

AHL is [N-] acyl-homoserine lactones. hese are small signalling molecules which are employed in "quorum sensing" systems. They are also known as autoinducers (AIs) and are present in many Gram-negative bacteria. "Although the target genes regulated by AIs are extremely varied, the basic mechanism of AIs biosynthesis and gene regulation seems to be conserved in different bacteria. The general feature of gene regulation by AIs is cell-density dependence, also known as "quorum sensing". At low cell densities, the AIs are at low concentrations, and, at high cell densities, the AIs can accumulate to a concentration sufficient for activation of related regulatory genes. Because the concentration of AHL's is a key factor in determining virulence gene expression in several pathogenic bacteria, it is possible to develop a strategy for disease control by controlling production of AIs or eliminating AIs produced by pathogenic bacteria.

AiiA, an enzyme that inactivates the acylhomoserine lactone quorum-sensing signal.