A DEFINED AGAR MEDIUM FOR GENETIC TRANSFORMATION OF NEISSERIA MENINGITIDIS

Abstract

An agar medium was developed for use in quantitative genetic studies of Neisseria meningitidis strain 15. It contains eight inorganic salts, sodium citrate, sodium lactate, arginine, cysteine, glycine sodium glutamate, and purified agar. Abundant surface growth in the ab-sence of supplemental carbon dioxide was obtained during 50 serial subcultures. A close correspondence was found between numbers of parental type colonies developing on the defined medium and on a complex medium. Cells subcultured serially three or four times on defined agar medium and placed directly into a solution of transforming deoxyribonucleic acid in defined liquid medium were susceptible to transformation without additional supplements. Of the treated population, 0.1 to 0.3% of the cells were transformed to streptomycin resistance.