Williams B, Van Benschoten A, Cimermancic P, Donia M, Zimmermann M, Taketani M, Ishihara A, Kashyap P, Fraser J, Fischbach M. Discovery and characterization of gut microbiota decarboxylases that can produce the neurotransmitter tryptamine. Cell Host Microbe. 2014;16(4):495–503. PMCID: PMC4260654