营养物质对细菌质粒pEA9∷Km在土壤中接合转移频率的影响

EFFECTS OF CARBON SOURCES ON CONJUGATIVE TRANSFER RATE OF BACTERIAL PLASMID pEA9∷KM IN SOIL

用成团肠杆菌 (Enterobacteragglomerans)T7(pEA9∷Km)为供体菌 ,以E .a .339(pEA9-)为受体菌在天然土壤中进行接合实验 ,测定各种营养物质对重组质粒pEA9∷Km同源接合转移频率的影响 .实验发现 ,如果在土壤中只加入生理盐水或无机盐培养基 ,就观察不到细菌数量的增加和质粒的转移 ;只有加入碳源物质后才检测到细菌数量的增加和质粒的接合转移 ,接合转移频率的大小位于 1.2× 10 -4 ～ 4.4× 10 -4 之间 ,与所加碳源物质的种类关系不大 .图 2表 1参

Using E.a. 339 T7(pEA9∷Km) as donor and E.a. 339(pEA9 -) as recipient conjugation experiments were performed in soil.In these experiments the effect of variable nutrients (LB,sucrose,ground sugar beets) on the transfer efficiency was investigated. Without additional supplements neither growth nor conjugation of bacteria could be detected in the soil. Only after addition of C sources growth and plasmid transfer were observed. The rates of transfer, however, were not significantly dependent on the sort of added C source and were found between 1.2×10 -4 and 4.4×10 -4 transkonjugants/donor. Fig 2, Tab 1, Ref 13