But in s . mycarofaciens , there is no distinctive propionate kinase , so that the utilization rate of propionic acid is lower than that of acetic acid . for this reason , it is hoped that the higher producers would be obtained by protoplast interspecies fusion between s . mycarofaciens and s . erythreus , which would transfer propionate kinase of s . erythreus to s . mycarofaciens . therefore , the fusion cells could use propionic acid as precursor in synthesis of mdma _ ( 1 ) , which would reduce the production costs 根据文献报道，红霉素链霉菌中的丙酸激酶对丙酸的利用率是对乙酸的利用率的13倍；而在生米卡链霉菌中，无特异的丙酸激酶，菌体对丙酸的利用低于对乙酸的利用，因此希望利用原生质体种间融合的方法将红霉素链霉菌的丙酸激酶基因转移到生米卡链霉菌中，从而使融合子能够利用丙酸盐作为合成mdma _ 1的前体，提高mdma _ 1的产量，降低生产成本。
Using ex vivo gene transfer technique , exogenous gene was introduced to the liver graft during cold preservation and express locally in the graft . the effect of inhibition of rejection and inducing liver graft tolerance was observed . through this study , the possibility of achieving graft tolerance by gene transfer without routine immunosuppressive drugs was explored 我们采用adeasy腺病毒载体系统，自行构建携带huctla4 - ig的重组腺病毒，通过先体外后体内( exvivo )基因转移技术，于供肝冷保存时，将该治疗基因导入大鼠移植肝，使其于移植肝局部表达，观察其抑制排斥反应，诱导大鼠移植肝免疫耐受的作用。
2 . rat orthotopic liver trarlsplantation was performed in the strong rejecter combination of bn ( rtl " ) to lew ( rtl l ) . this al1ogenic rejection model was stable and the survival time without immunosuppression agents was less than three weeks ( the average survival time was l 6 . 6 i 2 . 5 days , n = 5 ) 建立了大鼠bn ( rt1 ~ n ) lew ( rt1 ~ l )原位肝移植同种异体排斥模型，该模博士学位论义基因转移hu la个ig诱导大鼠移植肝免疫耐受的实验研究中文摘要型排斥反应时间较为恒定，在不应用免疫抑制剂的情况下，生存期3周（平均生存时问人66士2
