Genetic Transformation of Neisseria catarrhalis by Deoxyribonucleate Preparations having Different Average Base Compositions

Abstract

The base contents of deoxyribonucleate (DNA) preparations from 7 strains of Neisseria catarrhalis were determined chromatographically. Three non-overlapping classes were distinguished by mole % guanine + cytosine. These centred about the values 41% (2 strains), 42.3% (4 strains, including atcc 8193), and 44·5% (strain nctc 4403), Each of the 7 strains was capable of undergoing genetic transformation. DNA preparations from spontaneous streptomycin-resistant mutants of all 7 strains elicited transformation of recipient strains in all 49 possible combinations. Results with this group, therefore, do not support the hypothesis that success in transferring genetic information between 2 strains requires identity of average DNA base contents. Differences of reciprocal transformation frequencies and of 4 physiological characteristies (nitrate reduction, pigment production on vancomycin-containing agar, hydrolysis of gelatin, and growth at 28°) appeared to separate 6 of the strains of Neisseria catarrhalis from the seventh (nctc 4103), which may properly be named N, cincrea.