Rice University researchers found vitamin B12 promotes survival during infection by improving mitochondrial health. The expression of a fluorescent protein (top left) reflects buildup of a toxic metabolic product, propionate, in mitochondria on diets low in B12, as compared (bottom left) to those receiving sufficient B12. Mitochondrially targeted fluorescent protein (center) reveals fragmentation of mitochondria when B12 is low, and dead worms stained with fluorescent dye (bottom right) demonstrate the decreased survival rate of worms infected by the pathogen Pseudomonas aeruginosa. (Image courtesy of Natasha Kirienko/Rice University)