Intrageneric transformation of neisseria gonorrhoeae and neisseria perflava to streptomycin resistance and nutritional independence.

Auxotrophic mutants of Neisseria gonorrhoeae and Neisseria perflava were transformed to prototrophy using homologous and heterologous deoxyribonucleic acid (DNA). Within either species the efficiencies of transformation for nutritional markers were found to be very similar to the values obtained for transformation to streptomycin resistance. The number of transformants in the interspecific N. perflava (donor) - - leads to N. gonorrhoeae (recipient) cross was 100-fold lower than the number obtained in the intraspecific N. gonorrhoeae - - leads to N. gonorrhoeae cross for streptomycin resistance, as well as for several nutritional markers. In the reciprocal experiment the difference in the number of transformants in the interspecific N. gonorrhoeae - - leads to N. perflava cross and the number obtained in the intraspecific N. perflava - - leads to N. perflava cross varied from 600 to 1,000-fold for the streptomycin resistance marker. Of greater interest was the finding that N. perflava auxotrophs, although transformable to prototrophy with wild-type N. perflava DNA, were not transformed to nutritional independence by gnoncoccal DNA. These same mutants were transformable to streptomycin resistance using the heterologous gonococcal DNA. When the DNAs of N. meningitidis, N. flava, and N. lactamicus were used to transform N. gonorrhoeae to prototrophy or streptomycin resistance, the transformation frequencies obtained fell along a gradient that in general reflected taxonomic relationships. On the other hand, with N. perflava as the recipient for these same DNAs, only N. flava DNA could transform auxotrophs to prototrophy, although transformation to streptomycin resistance occurred in all cases. DNA from N. perflava - - leads to N. gonorrheae streptomycin-resistant or Ade+ intergenotic transformants transformed N. gonorrhoeae cells at a 100-fold-higher efficiency than did DNA from N. perflava. Our findings suggest that (i) N. gonorrhoeae and N. perflava are more closely related than hitherto suspected and (ii) N. perflava is more selective with respect to heterologous DNA than is N. gonorrhoeae.