高效液相色谱法测定替米考星含量

建立了替米考星含量测定的HPLC方法。采用C18色谱柱(5μm,4.6 mm×250mm),乙腈+四氢呋喃+磷酸二丁胺为流动相,流速1.0 mL/m in,检测波长280 mn,以HPLC外标法测定替米考星含量。结果表明,实验测得的峰面积与对应的浓度呈良好的线性关系,其线性范围为0.25~0.75 mg/mL(r=0.999 9),平均回收率为99.81%。本法简便、准确、快速,是测定替米考星含量的良好方法。     

An Inter‐Subspecies Cloned Buffalo (Bubalus bubalis) Obtained by Transferring of Cryopreserved Embryos via Somatic Cell Nuclear Transfer

The aim of this study was to explore the feasibility of cryopreservation of inter‐subspecies cloned embryos in buffalo. In our experiment, river buffalo ear fibroblast nucleus was fused into swamp buffalo oocyte cytoplasm. The blastocyst formation rate for nuclear transfer of freshly thawed cells was not different from those of growing cells, confluent or serum‐starved cells. A total of 122 cloned blastocysts derived from cryopreserved fibroblasts were cryopreserved and thawed, 37 were survived, the cryosurvival rate was 30.3%. The survived blastocysts were transferred into 15 recipient buffalos. Five of the recipients established pregnancy, but four of them aborted on day 53, 59, 145 and 179 of gestation respectively. One cross‐bred buffalo (Murrah × Swamp buffalo (2n = 49) received three embryos delivered a 40.5 kg female calf by natural delivery on day 320 of gestation. Up to now (13‐month old), the cloned calf has been growing well with no abnormity observed. These results demonstrated that cryopreservation of inter‐subspecies cloned embryos is feasible to produce buffalo offspring.