敲除鸡伤寒沙门菌(SG)减毒疫苗株97A asd基因,构建宿主载体平衡致死系统并表达新城疫病毒(NDV)F蛋白,构建二价活菌苗.PCR扩增两段位于asd基因外侧的序列作为等位基因,以氯霉素抗性(CmR)基因替代asd基因,构建自杀质粒pGMB151△asd::CmR,通过E.coli x7213与SG97A固相杂交,将质粒转入SG97A,反向筛选获得SG97A△asd::CmR,利用质粒pCP20去除CmR后,DAP的依赖菌株命名为SG97 A△asd.将含asd基因的质粒pYA3334转入SG97A△asd中构建宿主载体平衡致死系统,并表达NDV-F蛋白.结果表明,通过等位基因重组方法,成功构建SG97A△asd及宿主载体平衡致死系统,重组菌能够表达NDV-F蛋白,并能在鸡体内诱导产生特异性抗体.本研究成功构建SG97A△asd宿主载体平衡致死系统,并表达NDV-F蛋白及其诱导宿主产生抗体,为应用该系统构建二价活菌苗的研究奠定了基础.

In this paper,the Backlund transformation to the(2+1)-dimensions nonlinear dispersive long wave equation is derived by using the homogeneous balance method.And the exact solutions of 4 families are given by means of Backlund transformation,including multi-solitary solutions,the exponential function solutions,the hyperbolic function solutions and the triangular function solutions.