TRANSFORMATION OF V-FACTOR INDEPENDENCE FROM HAEMOPHILUS-DUCREYI TO HAEMOPHILUS-INFLUENZAE AND HAEMOPHILUS-PARAINFLUENZAE

Genes conferring V-factor independence in both reference and clinical strains of Haemophilus ducreyi were transferred to Haemophilus influen zae Rd and Haemophilus parainfluenzae 14 by transformation. Each trans formant of a plasmid-free H. influenzae Rd acquired a small 5.25kb pla smid. Although several extraction methods were used, we were not able to detect this plasmid in the original H. ducreyi strains by agarose g el electrophoresis. The plasmid recovered from the transformants was o f the same size as that conferring V-factor independence in four unusu al H. parainfluenzae strains previously isolated from unrelated source s.