TRANSPOSON MUTAGENESIS OF HAEMOPHILUS-PARAGALLINARUM WITH TN916

The Gram-positive transposon Tn916 was introduced into two strains of Haemophilus paragallinarum by electroporation of the suicide plasmid p AM 120 (pGL 101::Tn916). Tetracycline resistant mutants of H. paragall inarum strains Tw-1 and 221 were recovered at frequencies of 2.1 x 10( -6) and 4.5 x 10(-7) per viable cell electroporated, respectively. Tn9 16 generates stable single insertions within different sites of the H. paragallinarum chromosome. One Tw-1::Tn916 mutant had the Tn916 inser tion in the cryptic plasmid p250. This study indicates the potential u se of Tn916 as a genetic tool for insertional mutagenesis of H. paraga llinarum.