CONJUGAL TRANSFER OF TN916, TN916-DELTA-E, AND PAM-BETA-1 FROM ENTEROCOCCUS-FAECALIS TO BUTYRIVIBRIO-FIBRISOLVENS STRAINS

Anaerobic filter matings of Butyrivibrio fibrisolvens H17c, CF3, D1, or GS113, representing different DNA relatedness groups, were done with Enterococcus faecalis CG110, which contains chromosomally inserted Tn916. Tetracycline-resistant transconjugants were obtained with each mating pair at average frequencies of 4.4 x 10(-6) (per recipient) and 5.2 x 10(-6) (per donor). The transfer frequencies of Tn916 into B. fibrisolvens varied 5- to 10-fold with mating time, strain, and growth stage. By using Southern hybridization with pAM120 as the probe, Tn916 was shown to insert at one or more separate chromosomal sites for each strain of B. fibrisolvens. Retransfer of Tn916 from B. fibrisolvens H17c or CF3 to E. faecalis OG1-X or JH 2-2 or to B. fibrisolvens D1 or GS113 could not be shown. Matings of E. faecalis RH110, which contains chromosomally inserted Tn916-DELTA-E, with B. fibrisolvens 49, H17c, D1, CF3, GS113, or VV-1 resulted in erythromycin-resistant transconjugants at average frequencies of 5.3 x 10(-7) (per recipient) and 2.5 x 10(-7) (per donor). Tn916-DELTA-E was shown by Southern hybridization with pAM120 to insert at one or more sites in the chromosome of each strain. B. fibrisolvens H17c was anaerobically filter mated with E. faecalis JH 2-SS, which contains pAM-beta-1. Erythromycin-resistant transconjugants were obtained at frequencies of 2 x 10(-5) (per recipient) and 6 x 10(-5) (per donor). The presence of pAM-beta-1 in these transconjugants could not be shown by agarose gel electrophoresis of plasmid minilysates but could be shown by Southern hybridization analysis. Retransfer of pAM-beta-1 from B. fibrisolvens H17c transconjugants in matings with B. fibrisolvens D1 or GS113 or with E. faecalis JH 2-2 could not be shown. These data are the first to show stable transfer of a plasmid (pAM-beta-1), transposons (Tn916, Tn916-DELTA-E), or genes (erythromycin and tetracycline resistances) from nonruminal species to ruminal species of bacteria.