The collaborative efforts of two common gut microbes could increase the calories that a person extracts from food and stores as fat, a new study in mice suggests.
Trillions of bacteria and archaea—single-celled organisms that resemble bacteria but form another branch of life—occupy the intestines of healthy people and other animals. These microbes provide many benefits to their hosts, such as breaking down nutrients. Scientists have suspected that microbial species change each other's digestive roles, and researchers are now beginning to work out these complex interactions.
To investigate how one human-gut bacterium interacts with the most common human-gut archaeon, microbiologists Jeffrey I. Gordon and Buck S. Samuel of Washington University in St. Louis experimented with mice specially bred and raised to be missing all gut microbes.
The researchers fed some of the mice a solution containing the bacterium Bacteroides thetaiotaomicron and gave