Word: humanity
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Dates: during 2000-2009
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...mice that suggests that heavy bodies may have a different makeup of gut bugs than thin ones. The gut microbiota of obese mice has been shown to have significantly more of one main type of bacteria called Firmicutes and fewer of another kind called Bacteroidetes (both types populate human guts as well); in normal mice, the distribution is the opposite. Jeffrey Gordon at Washington University in St. Louis, Mo., who conducted the previous research, experimented again with mice for the new paper. This time, however, he and his team used human microbiota to colonize mouse guts and then...
Researchers started with mice that were specially bred to be germ-free - with no gut microbiota of their own - and to be able to nurture human gut microbiota. Researchers injected the mice with samples of fresh and frozen human feces, the bacteria from which took hold and colonized in the gut of the mice. If that surprises you, it absolutely stunned the researchers. "We were surprised that so much of the diversity present in human microbial communities could be recaptured in mice," says Gordon, who has been studying gut microbiota for more than five years...
...fact that the human gut flora flourished in the rodents was indeed an experimental coup. Since the mice were genetically engineered to be germ-free, lacking a functioning immune system, the scientists could be certain that any bug colonies that took hold in the mouse guts originated entirely from the human sample, not the mice. Being able to recreate the living human gut environment so faithfully in an animal was a welcome prize. (Read "The Year in Medicine 2008: From...
...contained in those bacteria. That meant researchers could determine not only which species of bacteria were present and in what proportions, but also which genes these bugs were actively using in different conditions. Before such genomic-analysis technology became available, researchers could study only the gut microbes (animal or human) that could be cultured outside their intestinal home - something that not all of the oxygen-shunning bugs were amenable to - but never the complete microbiota of the gut. "We cannot recapitulate the entire microbial diversity that exists in these complex communities. We simply don't know how to culture them...
...exerted influence on genes, may have a surprisingly powerful effect, changing how a body's genes would normally control the way the body digests food and breaks it down into energy. It makes sense, when you consider that the great majority of the cells and genes in the typical human body belong to the microbiota. "There is a vast reservoir of attributes associated with our human physiology that is derived from our gut microbial communities," he says. "Our genetic landscape is actually an amalgam, so it's slightly different from the genetic determinism of human genes flowing from parent...