The human body is full of tiny microorganisms, and the GI tract is home to the largest concentration and highest diversity of bacterial species. But how do these organisms persist and thrive in a system that is constantly in flux due to foods and fluids moving through it? A team led by Caltech biologist Sarkis Mazmanian believes it has found the answer, at least in one common group of bacteria: a set of genes that promotes stable microbial colonization of the gut.

A team of researchers led by biologists at Caltech has found that, in mouse models, the molecule microRNA-146a (miR-146a) acts as a critical regulator and protector of blood-forming stem cells during chronic inflammation, suggesting that a deficiency of miR-146a may be one important cause of blood cancers and bone marrow failure.

Biologists at Caltech have found that neural-crest stem cells—multipotent, migratory cells unique to vertebrates that give rise to many structures in the body such as facial bones and smooth muscle—play a key role in building olfactory sensory neurons in the nose.