Bacteroides Influence on Host Behavior: Difference between revisions
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==Introduction== | ==Introduction== | ||
<br> | <br>Bacteria often live in a special mutualism with large multicellular organisms: one such relationship of particular interest is that of the human digestive system and its "gut flora", or the microbial life that colonizes it. It is fairly intuitive that in such a relationship, the host will dictate temperature, pH level, substrate availability, and a variety of other environmental factors that will determine what types of bacteria are able to colonize it, how these bacteria will behave, and how successful any given species will be in that environment. What is not always such an intuitive aspect of the host/bacteria relationship is the role that the bacteria may play in the behavior and physiology of the host.<br> | ||
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The rise in obesity in the western world over the past several decades has prompted researchers to explore possible explanations for this drastic shift in human physiology. An important determinant of physiology of an individual is that individual's particular genome, and while this may account for a natural tendency towards weight gain for certain genotypes, the human genome has certainly not undergone a radical transformation since the "obesity epidemic" hit the western world. If we look at what has changed in the past few decades, we see people consuming larger-portioned, higer-calorie diets: but how and why does this shift in diet translate to a shift in body composition? Scientists are now looking at the role of the human body as a host to a plethora of bacteria, in particular, the inhabitants of the human gut-referred to collectively as the microbia. The gut flora engage in a key mutualistic relationship with the host, aiding in digestion. The microbia is composed of approximately 10<sup>13</sup> organisms that fall into somewhere between 500 and 1,000 species of bacteria (REF). Of these bacteria the classes Bacteriodes and Firmicutes make up a substantial portion: 92.6% of all gut flora fall into one of the two classes (REF).<br> | |||
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==The Human Gut Flora== | ==The Human Gut Flora== | ||
Revision as of 03:33, 15 April 2009
Introduction
Bacteria often live in a special mutualism with large multicellular organisms: one such relationship of particular interest is that of the human digestive system and its "gut flora", or the microbial life that colonizes it. It is fairly intuitive that in such a relationship, the host will dictate temperature, pH level, substrate availability, and a variety of other environmental factors that will determine what types of bacteria are able to colonize it, how these bacteria will behave, and how successful any given species will be in that environment. What is not always such an intuitive aspect of the host/bacteria relationship is the role that the bacteria may play in the behavior and physiology of the host.
The rise in obesity in the western world over the past several decades has prompted researchers to explore possible explanations for this drastic shift in human physiology. An important determinant of physiology of an individual is that individual's particular genome, and while this may account for a natural tendency towards weight gain for certain genotypes, the human genome has certainly not undergone a radical transformation since the "obesity epidemic" hit the western world. If we look at what has changed in the past few decades, we see people consuming larger-portioned, higer-calorie diets: but how and why does this shift in diet translate to a shift in body composition? Scientists are now looking at the role of the human body as a host to a plethora of bacteria, in particular, the inhabitants of the human gut-referred to collectively as the microbia. The gut flora engage in a key mutualistic relationship with the host, aiding in digestion. The microbia is composed of approximately 1013 organisms that fall into somewhere between 500 and 1,000 species of bacteria (REF). Of these bacteria the classes Bacteriodes and Firmicutes make up a substantial portion: 92.6% of all gut flora fall into one of the two classes (REF).
The Human Gut Flora
A diverse range of substrates enter our bodies to be broken down and converted into energy. While our digestive system is able to break down many substrates, it relies heavily on the plethora of microbes living in it to metabolize certain substrates. The bacteria present in the human gut aid in catabolism of many molecules, some of which would even be toxic to the digestive system in the absence of bacteria. Of the 1013 some organisms who call the human gut home, two classes of bacteria are particularly important: Bacteroides and Firmacutes make up around 92.6% of all the microbes associated with the human microbia (REFERENCE). Bacteroides reside in the human colon, and are gram-negative, rod shaped bacteria that use anaerobic respiration to break down polysaccharides from plant fibers.
What this Means for Humans
Include some current research in each topic, with at least one figure showing data.
Possible Therapeutic Options
Include some current research in each topic, with at least one figure showing data.
Conclusion
Overall paper length should be 3,000 words, with at least 3 figures.
References
Edited by student of Joan Slonczewski for BIOL 238 Microbiology, 2009, Kenyon College.
