For decades, scientists have wondered how living organisms manufacture the essential vitamin B12. Now, using laundry whitener and dirt-dwelling bacteria—the everyday ingredients of an undergraduate science experiment—researchers may have found the major clue they need to solve the mystery. Researchers have discovered the first known mutant bacteria with a specific defect in a gene involved in the least-understood part of B12 synthesis. (Proceedings of the National Academy of Sciences, February 20, 2006)
