For more than half a century, researchers have known that the bacteria that colonize the gastrointestinal tract of mammals influence their host's cholesterol metabolism. Now, Jens Walter and colleagues of the University of Nebraska show that changes in cholesterol metabolism induced by diet can alter the gut flora. The research was published online ahead of print in the journal Applied and Environmental Microbiology.
In the study, the researchers added plant sterol esters to the diets of hamsters. The overall effect of this was to inhibit several bacterial taxa, from the families Coriobacteriacea and Erysipelotrichaceae, says Walter. But the immediate effect of the plant sterols was to physically block cholesterol absorption by the intestine. That decreased cholesterol levels in the liver and the plasma, prompting the hamster's body to respond by synthesizing more cholesterol. That, in turn, boosted cholesterol excretion into the gut, and that extra cholesterol was the direct inhibitor of those bacterial families.
"The abundance of these bacterial taxa and the levels of cholesterol in the fecal samples followed a mathematical model of bacterial inhibition," says Walter.
Practically speaking, the microbial inhabitants of the gut are part of the metabolic system. Researchers have shown that certain health problems are related to changes in the gut flora, such as can be induced by overuse of antibiotics. Since changes in diet can influence composition of the gut flora, health problems such as obesity might be targeted by dietary interventions designed to suppress bacteria that contribute to weight gain. "However, for these to be successful, we need to know which bacterial patterns not only are associated with disease, but actually contribute to it," says Walter, noting that his research showed that some alterations associated with metabolic disease might be the consequence, rather than the cause of the disorder.
Walter says that the work was a real student project. Among the coauthors, three were graduate students, and two were undergraduates. "As a supervisor, it is extremely nice to see young scientists work as a team, and staying dedicated through the five years that this project took to complete," he says.
American Society for Microbiology: http://www.asm.org
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
The DNA in this ancient Siberian leg bone shows that the man had Neanderthal ancestors — yet more proof that humans and Neanderthals interbred. And he lived much farther north than expected.
The North Carolina coast may be the last place you'd think to find a sunken German submarine from World War II. But that's what Joe Hoyt — a nautical archeologist — found on a recent expedition to the ocean floor. Robert Siegel talks to him about the underwater battle site there.
Frustrated scientists argued Wednesday that making nasty viruses even worse in the lab provides crucial insight into preventing pandemics. Others say it just ups the risk a lab germ will start one.
The camel cousin evolved fluff instead of fat because it was able to linger in an evolutionary slow lane, suggest newly sequenced genomes
Archaeologists unearthed the missing head of one of the two sphinxes found guarding the entrance of an ancient tomb in Greece's northeast, as the diggers made their way into the monument's inner chambers, the culture ministry said on Tuesday.
In what the medical community is calling an incredible breakthrough, a Polish man who was left a quadriplegic after a stabbing, can walk again. The miraculous procedure involved doctors taking cells from his nose and implanting them into his spinal cord.
In a new book, San Francisco-based photographer Susan Middleton captures the curious gestures and expressions of marine invertebrates
Lab at the University of Texas at San Antonio gets Pentagon funding to see if brain waves can direct drone movement
After a severe brain injury, some people remain in a vegetative or minimally conscious state, unable to speak or move intentionally, and apparently unaware of the world around them. But in recent years, neuroscientists have found signs that some of these patients may still be conscious, at least to a degree. Now researchers have used a branch of mathematics called graph theory to search for neural signatures of consciousness.
Few parasitoids are more bizarre or disturbing than the wasps of the genus Glyptapanteles, whose females inject their eggs into living caterpillars. Once inside, the larvae mature, feeding on the caterpillar’s body fluids before gnawing through its skin en masse and emerging into the light of day. And despite the trauma, not only does the caterpillar survive---initially at least---but the larvae proceed to mind-control it, turning their host into a bodyguard that protects them as they spin their cocoons and finish maturing. Then, finally, the caterpillar starves to death, but only after the tiny wasps emerge from their cocoons and fly away.