The magazine of the european research area European Commission Copenhagen, a missed chance?

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Cooperate or die

A team of French and Portuguese 

researchers from the Institut 

Pasteur (FR) and Lisbon University, 

who published a study in the 

journal Current Biology, looked 

at the cooperation mechanism 

at work on the microbial scale 

ZEITGEIST

© Joachim Bur

ger

© Shutt

erst

ock/Anat-

oli

DNA analysis carried out at a Mainz 

University laboratory.

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IN BRIEF

 research

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eu No. 63 | APRIL 2010 

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in the case of Escherichia Coli. 

This bacteria is found in abun-

dance in the intestinal flora, 

enjoying neighbourly relations 

with the human body. However, 

any change in the interaction 

with the latter or with other 

microbes is enough to render 

it very virulent. At the same time 

its secretome – the proteins on 

which its vital functions depend – 

can be easily exploited by other 

microbes, by means of the hori-

zontal transfer of genes, a non-

sexual process by which very 

mobile genes, encoded in the cell 

plasmid, ‘jump’ from one organism 

to another. It is this that renders 

Escherichia Coli a potential even 

if unintentional ‘cooperator’. 

The question for the researchers 

was to understand why this 

phenomenon has endured when 

it is of little benefit to the helping 

organisms – and at times even 

harms them. According to their 

study, the answer lies in a triple 

process. Many of the secretome 

genes have cooperative traits that, 

once transferred to other organ-

isms, will convert these into 

cooperators. To maintain this 

new population they are coupled 

with other genes that impose 

a punitive strategy of the kind 

‘cooperate or die’. Finally, the 

genetic similarity of the infected 

individuals will favour the main-

tenance of these traits from one 

generation to the next by virtue 

of what is known as ‘kin’ selection. 

The study of this process opens 

the door to a better knowledge 

of bacteriological growth and its 

potential manipulation.