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bio_man bio_man
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Posts: 33243
13 years ago
Bacteria in the Gut May Influence Brain Development

http://images.sciencedaily.com/2011/02/110201083928-large.jpg

One type of bacteria normally found in the gut is E. coli. E. coli bacteria serve the useful task of keeping other bacterial organisms in check (however, the O157:H7 E. coli strain produces a potent toxin).

The research team compared behavior and gene expression in two groups of mice -- those raised with normal microorganisms, and those raised in the absence of microorganisms (or germ-free mice). The scientists observed that adult germ-free mice displayed different behavior from mice with normal microbiota, suggesting that gut bacteria may have a significant effect on the development of the brain in mammals.

The adult germ-free mice were observed to be more active and engaged in more 'risky' behavior than mice raised with normal microorganisms. When germ-free mice were exposed to normal microorganisms very early in life, as adults they developed the behavioral characteristics of those exposed to microorganisms from birth. In contrast, colonizing adult germ-free mice with bacteria did not influence their behavior.

Subsequent gene profiling in the brain identified genes and signaling pathways involved in learning, memory and motor control that were affected by the absence of gut bacteria, highlighting the profound changes in the mice that developed in the absence of microorganisms. This suggests that, over the course of evolution, colonization of the gut by microorganisms (in total 1.5 kilograms) in early infancy became integrated into early brain development.

"The data suggests that there is a critical period early in life when gut microorganisms affect the brain and change the behavior in later life," says Dr. Rochellys Diaz Heijtz, first author of the study.

"Not only are signal substances like serotonin and dopamine subject to regulation by bacteria, synapse function also appears to be regulated by colonizing bacteria," continues Prof. Sven Pettersson, coordinator of the study. "However, it is important to note that this new knowledge can be applied only to mice, and that it is too early to say anything about the effect of gut bacteria on the human brain."

In addition to Sven Pettersson and Rochellys Diaz Heijtz, Prof. Hans Forssberg at Stockholm Brain Institute (SBI) and Karolinska Institutet, and Dr. Martin Hibberd from the Genome Institute of Singapore (GIS) where involved in the research project. The findings presented are a result of a long-standing and ongoing collaboration between Karolinska Institutet and the GIS in Singapore aimed at exploring host-microbe interactions in a systematic manner.
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bio_man Author
wrote...
Educator
13 years ago
Most of our body cells are bacteria. Ten times more than our own cells ! Not to mention that some components of our own cells have bacterial origin ( mitochondria ). Our own DNA is riddled with segments of viral origin !
wrote...
Staff Member
Educator
13 years ago
It has effect on mice only and it's too early to decide whether it influences human behavior.
Mastering in Nutritional Biology
Tralalalala Slight Smile
bio_man Author
wrote...
Educator
13 years ago
If gut bacteria influences mice brains it is very likely that it also influences human brains. Gut bacteria have being co-evolving with mammalians for hundreds of millions years. Anyway, the title is caveatted by the word 'may'.
wrote...
Staff Member
Educator
13 years ago
It will maybe in the long run!
Mastering in Nutritional Biology
Tralalalala Slight Smile
wrote...
Staff Member
13 years ago
Padre, the 'long run' already happened and it took hundreds of millions of years. Remember, primitive mammalians were our remote ancestors. And it is possible that such co-evolution with gut bacteria started in even earlier ancestors like reptiles, fishes, etc.
- Master of Science in Biology
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