Emergence of Competence (for Transformation) of Three Hemophilus Species in a Chemically Defined Environment. †

Summary

Three species of Hemophilus, grown under the method of Goodgal and Herriott, were shown to emerge to a state of competence for transformation to SM-resistance in a chemically defined medium: L-aspartic, L-glutamic acids in buffered saline containing calcium and magnesium ions. The degree of competence of a “standard'culture was enhanced many-fold in 30 to 60 minutes even when diluted 10⁵-fold in the defined medium. The emergence of competence in the synthetic environment was temperature dependent and inhibited by chloramphenicol; multiplication was not necessary. Competent populations washed in the defined medium retain competence; in populations which have lost transformability as a result of washing in buffered saline, competence may be restored. Data presented suggest that the competence which emerges reflects the final attainment of the competent state rather than its “restoration'in cells which were competent at an earlier period during growth of the population.