A transmission electron microscope image of ribbonfish skin shows random arrangements of crystalline quinine embedded in cytoplasm (a). The arrangement of crystal layers reflects light across a broad spectrum. A nature-inspired method to model the reflection of light from the skin of silvery fish and other organisms may be possible, according to Penn State researchers.

How the host shapes the microbiota is
unclear. Gut microbes are well known to contribute to health and disease, but what has been less clear is how the host controls gut microbes. A study published January 13 in Cell Host & Microbe now reveals that mice and humans produce small molecules (microRNAs) from their GI tract, which are shed in feces, to regulate the composition of gut microbes and thereby protect against intestinal diseases such as colitis.