Specificity of Lactate for the Development of Competence in Haemophilus influenzae

Abstract

SUMMARYA number of common carbohydrates and polyols were tested to see if they could replace the lactate requirement for the development of competence in cultures of Haemophilus injluenzae. Pyruvate, fructose, and glucose, when tested in the presence of inosine, were slightly stimulatory. They gave respectively, 29, 25 and 13 % of the control value obtained with inosine and lactate. Under similar test conditions, mannose, mannitol, galactose, sorbose, sorbitol, ribose, glucosamine, rhamnose, D (-) arabinose, L (+) arabinose, xylose and fucose were inactive.In combination experiments, glucose, inosine and pyruvate, and fructose, inosine and pyruvate stimulated the development of competence to 50 to 70 % of the inosine and lactate control value. Without inosine, the stimulation due to glucose and pyruvate, and fructose and pyruvate was 3 and 9 %, respectively.