Credit: Nunez Laboratory, University of Michigan
Two microscope views of the lining of the intestines of mice that were born and raised in a germ-free environment at the University of Michigan. Left: The gut of a mouse that received a transplant of microbes from the gut of four-day-old normal mice, and then was exposed to Salmonella, while the other received a transplant of the four-day-old mouse microbes along with added Clostridia bacteria, before being exposed to Salmonella. The Clostridia protected from infection.