Intestinal Bacteria


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A current trend in biology is to examine the bacteria present in an environment by sampling their DNA. This approach isn’t perfect, but it does give us an idea what kinds of bacteria are present. In many cases we can culture the bacteria, so this is as close as we have come so far to identifying all the components of a bacterial ecosystem. This idea was recently applied to the human gut. It has been known for a long time that we have symbiotic relationships with bacteria in our guts in which we feed and protect them and they provide us with nutrients we can’t produce ourselves. A recent Science paper describes a metagenomic study of bacterial ecosystems in human guts and the authors suggest that these organisms may be providing humans with nutrients, energy, protection from cancer and pathogens, among other roles. Relationships of this type allow humans to utilize more various food sources without having to evolve the biochemical pathways to metabolize all the nutrients, or provide all the vitamins and other co-factors involved in human metabolism. Understanding the role these organisms play in human metabolism has a wide range of medical implications as well.


Original Science article
Gill, S.R. et al Science Vol. 312. no. 5778, pp1355-1359 (2005)

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