Suicidal bacteria illustrates evolution of co-operation
Salmonella typhimurium; suicidal cells sacrifice for the greated good
Bacteria have sometimes behaviour that can amaze scientists, by its complexity and efficiency. Salmonella can commit suicide and help their “brothers” to establish infections that are more damaging, thus helping their species. But scientists believe they have found the answer to this surprising kamikaze behavior.
This phenomenon which is called self-destructive cooperation often helps Salmonella typhimurium and Clostridium difficile establish powerful “citadels” of infection in the gut. Scientists from Switzerland and Canada studied this type of developing an infection, and the team led by Martin Ackermann of ETH Zurich in Switzerland made some interesting discoveries.
The bacteria inflames the gut and causes an eradication of the microflora, which is a competition for resource. However, in this process they destroy other bacteria too (most of it actually). After this assault there is no competition for the few bacteria remaining, which charge on the gut, claiming their victory.
“We thought it was a very strange phenomenon,” says team member Wolf-Dietrich Hardt, also at ETH Zurich. “The bacteria in the gut lumen are genetically identical, but some of them are prepared to sacrifice themselves for the greater good. You could compare this act to Kamikaze fighter pilots of the Japanese army.”
This suicidal act is caused by a genetic configuration, which is expressed only in some ocasions, not in all. Only a part of the bacteria have this suicidal gene, less than a quarter. If all of them would carry it, all of them would commit suicide as a consequence. The team concluded that some cells sacrifice for the greater good, which is quite an inventive and effective way of achieving a goal.
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Andrei is no scientist, but from an early age, he has been fascinated by science; that's why he went to college, and signed up for Geophysics. Feeling that there's a huge gap between science and average people, he rallied TP, started ZME Science, and gave it a green twist too.
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August 23rd, 2008 at 3:14 pm
The summary is very confusing, particularly the last paragraph.
The quoted scientist clearly states the bacteria are clonal (”genetically identical”), thus in the author’s simplified terms…ALL the bacteria “carry” the suicide gene, however only a fraction choose to express it. It’s not about the presence, it’s about the activation (which is vastly more interesting IMHO).
Good topic though!
August 23rd, 2008 at 6:25 pm
Boy why don;t they ALL kill themselves! Then we won’t have to worry about chowing down our jalapenos.
August 23rd, 2008 at 11:50 pm
Wow that is pretty wild!
RD
http://www.anotools.cq.bz
September 26th, 2008 at 4:17 am
This flies in the face of evolutionary theory. These bacteria lack the capacity for abstract thought, and have no desire or coding to compel them to further their species. They have in their DNA recipe book reproductive instructions; they have no such recipe for helping their neighbor.
December 9th, 2008 at 2:43 pm
The summary should include how this “suicidal” behavior assists the population. Why do they do it? Overpopulation? Lack of resources?
This seems like it could somehow be used to eliminate bacterial infections without antibiotics.