Metronidazole (8823 RP; "Flagyl") is a nitroinidazole derivative which has been shewn to be highly active against T. vaginalis, not only in the laboratory (Cosar and Julou, 1959) but also in vivo against human trichomoniasis in the female (Durel, Roiron, Siboulet, and Borel, 1959, 1960; Durel, Couture, Collart, and Girot, 1960; Nicol, Barrow, and Redmond, 1960; Rodin, King, Nicol, and Barrow, 1...

Earlier work in this Laboratory has established conditions for the formation of methionine, from homocysteine plus serine or formaldehyde, by soluble enzyme systems extracted from Eseherichia coli. A cofactor of the folic acid group* is essential, and with E. coli PA 15 an extract of the heated organisms, H4PtG3 and its N5and N'0-formyl derivatives are all effective. H4PtG inhibits competitivel...