Streptococcus faecalis의 pAM $\beta$$_1$을 lactobacillus casei로의 전이에 영향을 미치는 요인

Factors affecting transfer frequency of pAM$\beta$$_1$from streptococcus faecalis to lactobacillus casei

The streptococcal plasmid pAM$\beta_{1}$ (erythromycin resistance)was transferred via conjugation from Streptococcus faecalis DS 5 to Lactobacillus casei YIT 9018 by a filter mating method. The transfer frequency depended greatly on the type, pore size and side(front or back) of membrane filter. Water passing through a membrane under reduced pressure induced very tight contact between the cells, increased the transconjugation frequency about 1.3 to 37-fold when Millipore membrane filter (0.45.$\mu$m, front side up) was used.