Quorum Sensing in Bacteria

Chemistry News: Quorum-sensing signals control when bacteria turn deadly

Date: September 18 2014

Source: http://www.sciencedaily.com/releases/2014/09/140918205902.htm

A research team at University of Wisconsin-Madison has been focusing their efforts on discovering the ways that bacteria communicate. These single celled organisms seem to have an awareness of one another: how many bacteria are present, and what each bacterium’s function should be within the group

Quorum sensing (the way bacteria communicate) is based on the fact that a cluster or quorum of bacteria can communicate with each other using proteins and other organic molecules. A seemingly harmless bunch of bacteria can  soon turn deadly once an attack signal is received from one member of the quorum. As soon as this signal is received, then individual bacteria in the quorum respond appropriately by completing functions such as producing poisonous compounds, enzymes, or even biofilms to protect the quorum while it does its damage.


The research of Helen Blackwell and her graduate students, Joseph Gerdt and Christine McInnis has been focused on exactly the way that these bacteria communicate.  One of the ways they have been exploring the systems of communication  is by making artificial compounds that mimic the functions of the bacteria. They are tweaking the communication proteins the compounds have by making point modifications in the protein’s make up and have found that one simple change can cause bacteria to turn from unpathogenic to pathogenic. This shows, in the words of Christine McInnis, “…that small-molecule control of quorum sensing is very finely tuned, much more than we even expected." 


This research is especially valuable since many scientists believe that we are reaching the end of the usefulness of antibiotic drugs. Bacteria have evolved and  are able to change so rapidly that antibiotics are running out of options. A more effective way to control bacteria would be to simply render them useless. One such way is to control their communication with one another and prevent the signal that turns them pathogenic. This would make the 
bacteria ineffective within their quorums. This is the goal of the University of Madison-Wisconsin research team. Their hopes are to incorporate their findings into gram negative bacteria, which are especially hard to eliminate because of their double cell wall.

Images:   http://micro.digitalproteus.com/pics/grambacterium.jpg 
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