Adenosine Triphosphate and Other Requirements for the Utilization of Glucose by Agents of the Psittacosis-Trachoma Group

Abstract

Weiss, Emilio (Naval Medical Research Institute, Bethesda, Md.). Adenosine triphosphate and other requirements for the utilization of glucose by agents of the psittacosis-trachoma group. J. Bacteriol. 90: 243–253. 1965.—The agent of meningopneumonitis cultivated in the allantoic cavity of chick embryos and purified by differential centrifugations was employed for most of the studies of the requirements for glucose utilization. The evolution of C 14 O 2 from glucose- 1-C 14 was used as the criterion of metabolic activity in most experiments. The rate of glucose utilization increased somewhat during the first hour of incubation at 34.4 C and became approximately constant during the second hour. Changes in glucose concentration from 1 to 5 m m did not appreciably affect metabolic activity. More vigorous CO 2 production was obtained when the ratio of K + -Na + was >1 and, under certain conditions, when the concentration of inorganic phosphate was relatively high (0.05 m ). Glucose utilization was entirely dependent on added adenosine triphosphate (ATP) and Mg ++ . The effect of ATP was greatly reduced when the microorganisms were partially disrupted with sonic energy. Adenosine diphosphate (ADP) could be substituted for ATP, but the activity was reduced to less than 20%. ATP was not required when glucose-6-phosphate was substituted for glucose. With ADP and glucose, glucose-6-phosphate was an effective competitor of glucose utilization. Nicotinamide adenine dinucleotide phosphate (NADP) enhanced CO 2 production from carbon 1, but not from other carbons, with glucose and, especially, glucose-6-phosphate as substrates. ATP and NADP produced the above-described effects only when their concentrations were comparable to those of the substrates. These concentrations always exceeded the amount of CO 2 produced (0.05 to 0.5 μmole/mg of agent protein). The concentration of NADP could be reduced when oxidized glutathione was added. Diphosphothiamine had no effect on CO 2 production. Qualitatively similar results were obtained with the agent of trachoma purified from yolk sac. These experiments furnish evidence that agents of the psittacosistrachoma group, despite their enzymatic capabilities, require an exogenous source of energy.