Sunday, June 19, 2011

Barricading Bad Bacteria

When foreign bacteria decide to conquer our bodies, the environment turns hostile. War is soon declared with the influx of antibiotics allies. But the bacteria are able to counter our drugs with a more effective weapon - top of the range communication.

Bacteria are extremely hardy, surviving in every environment on earth. They are vital in the recycling of nutrients and therefore play a major role in the cycle of life and the functioning of the planet. But, like the widely studied bacterium Pseudomonas aeroginosa, they can also be the cause of death cancer and AIDS patients, cystic fibrosis sufferers as well as burn victims.

Being a single celled organism, communication is imperative for survival of the species. Bacteria are pretty harmless on their own, given their miniscule size. But given the right environment, often a host such as an animal or human body, they are able to grow and divide at a rapid rate. The host’s immune system, overwhelmed at the sudden explosion of its new resident, cannot produce a big enough army to combat the bacteria.

‘Quorum sensing’ is the term used to describe the way bacteria communicate through messages in their protein molecules. They are able to multiply undetected within a host until they reach a large concentration, making them harmful.

In 2007, researchers found the key protein in the hierarchy of quorum sensing which activates the chemicals used in communicating with other proteins. Just like a radio broadcast, this message is instant and effective, reaching every target in range. This was quite a break-through as scientists were now able develop drugs to target this key protein and therefore break the communication link.

The latest research, however, has explored bacteria communication more thoroughly, revealing that there is more to the chain of communication than previously thought. These signals which are sent from bacterium to bacterium, do so through ‘nanotubes’: tiny tunnels connecting each cell. Small proteins, molecules and genetic elements are exchanged via these tubes. Not only do nanotubes bridge communication within a species, but they also connect bacteria of different species.

Okay, bacteria communicate through tiny tubes to all other bacteria. So what?

This explains their ability to quickly build up a resistance to harsh environments. It facilitates antibiotic resistance, making our drugs increasingly ineffective. Therefore, by understanding the ins-and-outs of bacteria communication, new strategies can be developed to fight pathogenic bacteria.

If that is not enough to spark one’s interest, then try marvelling at the sheer genius of co-operation and co-ordination between millions of single cells, microscopic in size, which are able to bring down a massive, multi-celled body such as a human being. Now that’s team-work!

Source: Article reference: "Molecular Insights into Quorum Sensing in the Human Pathogen Pseudomonas aeruginosa from the Structure of the Virulence Regulator LasR Bound to its Autoinducer" by Matthew J. Bottomley, Ester Muraglia, Renzo Bazzo & Andrea Carfì


Viewed online [http://www.sciencedaily.com/releases/2007/05/070504140209.htm]


Journal reference: Gyanendra P. Dubey, Sigal Ben-Yehuda. “Intercellular Nanotubes Mediate Bacterial Communication”. Cell, 2011; 144 (4): 590 DOI: 10.1016/j.cell.2011.01.015


Viewed online [http://www.sciencedaily.com/releases/2011/03/110302080003.htm]

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