INTRODUCTION OF TN916 AND PAM-BETA-1 INTO STREPTOCOCCUS-BOVIS JB1 BY CONJUGATION

The transposon Tn916 and self-mobilizing plasmid pAM-beta-1 were conjugated from Enterococcus faecalis to the ruminal bacterium Streptococcus bovis JB1. Transconjugants were identified by resistance to tetracycline (Tn916) or erythromycin (pAM-beta-1) and by Southern hybridization analyses. Transfer frequencies were 7.0 x 10(-6) and 1.0 x 10(-6) per recipient cell for Tn916 and pAM-beta-1, respectively. The transconjugants JB1/Tn916 and JB1/pAM-beta-1 were used as donors for matings with E. faecalis, Bacillus subtilis, and the ruminal bacterium Butyrivibrio fibrisolvens. While pAM-beta-1 was successfully transferred to all three organisms, Tn916 was transferred only into B. subtilis and B. fibrisolvens at very low frequencies. This is the first report of conjugal DNA transfers between two ruminal organisms.