Gene transfer in the gastrointestinal tract

The maximum in vivo transfer rate of plasmid pAM beta 1 in the gut was 0.03 transconjugant per recipient cell, and this rate could be simulated in vit ro only by forced filter mating. Transfer was not detected in liquid cultur e matings. Our findings demonstrate that in vitro methods, such as forced f ilter mating and liquid mating, underestimate the in vivo rates of gene tra nsfer.