microbiota tagged posts

Andreas Bäumler and his team discovered how pathogens manipulate the intestinal environment to favor their own growth.

Why do some foodborne bacteria make us sick? A paper published Sept. 16 in the journal Science has found that pathogens in the intestinal tract cause harm because they benefit from immune system responses designed to repair the very damage to the intestinal lining caused by the bacteria in the first place. “The finding is important because it explains how some enteric pathogens can manipulate mammalian cells to get the oxygen they need to breathe,” said Prof. Andreas Bäumler, UC Davis School of Medicine...

Highlights •Dietary fiber with vitamin A increases the potency of tolerogenic CD103+ DCs •High-fiber diet protects mice against peanut allergy via gut microbiota and SCFA •High-fiber effects rely on epithelial GPR43 and immune cell GPR109a •Dietary fiber promotes TFH and IgA responses

The development of food allergies in mice can be linked to what their gut bacteria are being fed. Rodents that received a diet with average calories, sugar, and fiber content from birth were shown to have more severe peanut allergies than those that received a high-fiber diet. The researchers show that gut bacteria release a specific fatty acid in response to fiber intake, which eventually impacts allergic responses via changes to the immune system.

“We felt that the increased incidence of food allerg...

Mild cold and exercise stimulate creation of “beige fat” in white adipose tissue

It triggers a surprising metabolic mechanism: white fat cells are transformed into cells similar to brown fat ( ‘beige fat’), that protects the body against excess weight and its damaging consequences. In healthy humans, white adipose tissue constitutes ~25% of body mass. However, when in excess, white fat contributes to insulin resistance and diabetes. Conversely, brown fat improves insulin sensitivity and is reversely correlated to obesity.

In response to cold or exercise, cells similar to brown fat – the beige fat – can appear within the white fat, a phenomenon known as “browning...

A University of Oregon study finds abundance does not dictate the immune response to bacteria in the guts of zebrafish. This graphic depicts immune response (neutrophils, shown in green) to separate bacterial species, and the response when the two bacteria are placed into a germ-free fish gut at the same time. Credit: Courtesy of Annah S. Rolig

University of Oregon scientists have found strength in numbers doesn’t hold true for microbes in the intestines.The findings provide a path to study the function of each bacterial species in the gut and to eventually, perhaps, predict and prevent disease...