The carbon dioxide requirement of Neisseria gonorrhoeae.

In some microorganisms C02 can be replaced successfully as a growth factor by certain dicarboxylic acids which enter the Krebs cycle (Lwoff and Monod, 1946; Ajl and Werkman, 1948). Other microorganisms require C02 for growth even when cultivated on rather complex media (Steinman, et al., 1954; Mueller and Einton, 1941), and the biochemical basis for this need has remained obscure. In the course of investigations on the glutathione requirement of certain mutants of Neisseria gonorrhoeae, it was observed that this microorganism grew well in the absence of C02 provided a small amount of yeast extract was included in the medium. A survey of a number of different strains of N. gonorrhoeae obtained from various laboratories and from clinical cases revealed that the phenomenon was a general one and not restricted to the glutathione-less mutant. It was reported in a preliminary note (Griffin and Racker, 1955) that the yeast extract can be replaced by a combination of three factors: hypoxanthine, uracil, and oxaloacetate. It is the purpose of this paper to present the details of this investigation.