There are ten bacterial cells for each human cell in your body. You just know that all those trillions of microbes peacefully coexisting with us (mostly in our gut) are up to something - actually a hell of a lot. Imbalances in the composition of our internal microbial ecosystems have been associated with allergies, autoimmunity, intestinal infections, cancer and obesity.
But scientists are scratching their heads about exactly how to puzzle out the role any given resident species plays, or its response to environmental perturbations such as, say, a change in diet.
Along comes the husband-and-wife team of Justin Sonnenburg, PhD, and Erica Sonnenburg, PhD, and their Stanford colleagues, who show us, in a just-published paper in the journal Cell, one way to go about it. Using as their test tubes laboratory mice specially raised to be preternaturally free of resident germs, the investigators colonized the mice with two bacterial species that are common in people's digestive tracts. Then they let the two species duke it out under different dietary conditions. (Call it a "germ joust.") The hyper-simplified system allowed the researchers to tease out meaningful results.
The long-term goal is to up the number of human microbes introduced to the experimental mice, and gradually approach the complexity of the superorganism that dwells in our innards.
