Bugging bugs: Learning to speak microbe

[n2doc]

05 March 2010 by Hayley Birch

DEEP in your lungs, there's a battle raging. It's a warm, moist environment where the ever-opportunistic bacterium Pseudomonas aeruginosa has taken up residence. If your lungs are healthy, chances are the invader will be quickly dispatched. But in the mucus-clogged lungs of people with cystic fibrosis, the bacterium finds an ideal habitat. First, the microbes quietly multiply and then they suddenly switch their behaviour. A host of biochemical changes sticks the population of cells together, forming a gluey biofilm that even a potent cocktail of antibiotics struggles to shift.

Microbes like P. aeruginosa were once thought of as disorganised renegades, each cell working alone. Microbiologists like Thomas Bjarnsholt, who is battling to understand how P. aeruginosa causes chronic infection in people with cystic fibrosis, now know otherwise. They are up against a highly organised army, using a sophisticated communication system to coordinate its behaviour.

But it's Bjarnsholt's latest discovery that reveals microbes' gift for language: the bacteria aren't just talking amongst themselves, but also quietly listening in on signals sent by their human host. So when a cavalry of white blood cells arrives to repel the invading bacteria, the entrenched biofilm senses their presence, and launches a coordinated counterattack (Microbiology, vol 155, p 3500). The microbes release deadly compounds called rhamnolipids, which burst the white blood cells, killing them before they can even take aim, says Bjarnsholt, who is at the University of Copenhagen in Denmark.

Examples like this belie the notion that bacteria are simple, silent loners. Over recent decades, many species of bacteria have been shown to be in constant communication with each other. But now an even more sophisticated picture is emerging, one in which bacteria not only receive signals from each other, but also intercept them from the cells of their plant or animal hosts, including us.

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http://www.newscientist.com/article/mg20527501.300-bugging-bugs-learning-to-speak-microbe.html

[BrklynLiberal]

1. So that I can find this later.

[gimberly]

2. As usual, cooperation = success

It's not surprising at all that bacteria communicate via chemical signals; they've had billions of years to evolve, much longer than anything else. All living things are incredibly complex machines. AL

[Igel]

3. Most of us have had the same amount of time.

There are a few branches of microscopic organisms, some older than others. But ultimately the ancestors of the organisms that yield TB or diarrhea simply had a different set of mutations in a slightly different environment than human ancestors.

Pretty much the same length of time. Just different branch points and environments.