Bacteroides fragilis ss. vulgatus WIKIMEDIA, CDCThe mammalian gut microbiome is a teeming and dynamic community that adapts quickly to environmental shifts in the host. Researchers at Washington University School of Medicine in St. Louis, Missouri, have now identified some of the genes bacteria residing in the mouse gut use to adapt to changes in diet, according to a study published today (October 1) in Science. Previously, researchers trying to understand the incredible diversity of the gut microbiome have been limited by available tools to study genetic changes in gut. So Meng Wu, Jeffrey Gordon, and their colleagues developed a new method of tracking genetic changes in gut bacteria.
“[The study] elegantly demonstrates the functional principals of the microbiome,” said Joseph Petrosino, a microbiologist and geneticist at the Baylor College of Medicine in Houston, Texas, who was not involved with this study. “You’re really seeing the selective pressures at the genetic level.”
Wu created a large library of 87,000 to 167,000 different mutant strains of four different species of Bacteroides, a genus that is commonly found in intestines. She then colonized germ-free mice with the mutant strains and 11 other bacterial strains common in the gut to create simplified microbiota. She tracked the proportion of the strains that were recovered from the mice to gauge how well the strains adapted to the gut environment, giving each mutant strain a “fitness index” based on how ...
