Extended Data Fig. 1: The gut bacteria Clostridium sporogenes and Peptostreptococcus anaerobius produce tryptophan metabolites.

(a) Tryptophan metabolites in the medium and culture supernatants of C. sporogenes grown for 48 hrs in mGAM medium. Bars and error lines show mean ± s.d. of four independent biological replicates for C. sporogenes and three for control medium. (b) Tryptophan metabolites in the medium and culture supernatants of P. anaerobius grown for 48 hrs in mGAM medium in triplicates. Bars and error lines show mean ± s.d. of three independent biological replicates. (c) Tryptophan metabolites in serum (five) and in cecum (four) of germ-free (GF) and six gnotobiotic mice monocolonized with C. sporogenes (C. spo).