【摘要】 构建鼠伤寒沙门菌SL1344ΔcrpΔasd双基因缺失突变株,并对其生物学特性进行初步研究。首先以χ7213(pREΔasd)为供体菌,SL1344Δcrp为受体菌进行结合转移,通过自杀性质粒介导的等位交换技术两步法筛选SL1344的ΔcrpΔasd双缺失株。该缺失株在有外源DAP的存在下能够正常生长,且能稳定遗传缺失的asd基因;其血清型与亲本株SL1344Δcrp及强毒株SL1344保持一致;其生化特性与亲本株基本相同,但与强毒株相比变化较明显,且生长速度明显减慢;雏鸡毒力试验结果表明其毒力较SL1344降低约105倍。鼠伤寒沙门菌SL1344ΔcrpΔasd缺失株构建成功,为进一步开发以鼠伤寒沙门菌为载体的口服疫苗奠定了基础。更多还原

【Abstract】 Construction and identification of Salmonella typhimurium SL1344 mutant strain(SL1344ΔcrpΔasd),and the phenotype of SL1344ΔcrpΔasd mutant was analyzed preliminarily.Firstly,E.coli donor strainχ7213(pREΔasd)was conjugated with SL1344Δcrp,the recipient.The SL1344ΔcrpΔasd mutant was constructed through the two-step method introduced by the transduction of recombinant suicide plasmid.It indicated thatΔcrpΔasd mutant can grow normally when foreign DAP was supplied,and it was stabile with the recombinantΔasdgene in vitro,the O and H antigens were identical to SL1344Δcrpand SL1344strain.The fermentation patterns and growth rate of the mutant were different from SL1344strain,obviously,and the growth velocity of the mutant was more slow.The virulence of SL1344ΔcrpΔasd mutant strain was 105times lower than SL1344strain.The SL1344ΔcrpΔasd mutant was constructed successfully.It is considerable that thisΔcrpΔasd mutant could be a potential oral vaccine vector to express foreign antigen or act as a eukaruotic expression plasmid carrier.更多还原