In order to evaluate the toxicity of the bisphenol A (BPA) on the growth of zebrafish embryos, fertilized eggs were exposed to the concentration of 2.00, 4.00, 6.00, 8.00, 10.00, 15.00, 18.00, 22.00 and 25.00mg/L BPA ...In order to evaluate the toxicity of the bisphenol A (BPA) on the growth of zebrafish embryos, fertilized eggs were exposed to the concentration of 2.00, 4.00, 6.00, 8.00, 10.00, 15.00, 18.00, 22.00 and 25.00mg/L BPA for 72 h at 26±1℃. The results revealed that the sublethal toxicological endpoints induced by BPA were:delayed hatch> blood balk >cyst>altered axial curvature and tail malformation. The median embryo lethal concentration (LC50) after 24 h was 16.36 mg/L. We concluded that the BPA toxicity on zebrafish embryos were caused before 8h exposure and it was not the result of long-term accumulation. Therefore, BPA maybe cause altered gene expression at the early stage of zebrafish embryos. In the further studies, we will use the technology of genetic chips to look for the toxic mechanism of BPA.展开更多
A series of experiments were conducted to study the major procedures in nuclear transplantation such as oocyte enucleation and activation, electrofusion and developnent of the nuclear transplant embryos in the mouse, ...A series of experiments were conducted to study the major procedures in nuclear transplantation such as oocyte enucleation and activation, electrofusion and developnent of the nuclear transplant embryos in the mouse, rabbits and sheep. The important results are as follows:11. In the mouse, only 35% of the oocytes collected 15～16 h after hCG had a notable first polar body (FPb) and those without FPb were enucleated by removing cytoplasm from the PVS-wider side and the enucleation rate was similar to that in the oocytes with FPb, and the enucleation rate of removing 1/3 cytoplasm was remarkably higher than that of removing 1/4 cytoplasm. 2. Among the three fusion media tested, mannitol and sucrose solutions produced better results than M2 in electrofusion of mouse 2-cell embryos. Under favorable pulse conditions, the osmotic pressure of fusion medium had no motable effect on electrofusion, but as the conditions became so unfavorable that some embryos began to lyse, the fusion rates in hypertonie mannitol solution were significantly higher than those in isotonic or hypotonic solutions. A wide range of pulse strengths (0.31～2.04 by/ cm) and durations(10～1280 μs) were used and 100% of fusion were obtained in many cases. Optimal pulse durations were plotted for field strengths to obtain high fusion rates (96%～ 100%) in mouse2-cell embryos. 3. With one pulse of 0.45 by / cm, satisfactory results of mouse oocyte activation were obtained only when the duration increased to 160 μs or longer. The activation rate increased as the oocytes got older. Some of the oocytes ar. rested at metaphase Ⅲ after electrical stimulation and their proportion to the number of oocytes not activated increased with egg age. 4. 10% and 31% of the nuclear transplant embryos developed to morula or blastocyst stage in sheep and rabbits, respectively, with Chinese-made hormones and chemicals.展开更多
Factors affecting the in vitro germination and growth of Taxus cuspidata embryos were examined. DCR medium was the best among 6 basal media tested; embryos from stage II seeds were the optimal developmental stage for ...Factors affecting the in vitro germination and growth of Taxus cuspidata embryos were examined. DCR medium was the best among 6 basal media tested; embryos from stage II seeds were the optimal developmental stage for in vitro germination; as the seeds approached maturity, germinability of embryos decrease. Embryos cultured in darkness tended to form callus and decrease the frequency of germination; inoculation method obviously affected frequency of embryo germination. Embryos cultured in optimal conditions developed into seedlings in 2 months.展开更多
文摘In order to evaluate the toxicity of the bisphenol A (BPA) on the growth of zebrafish embryos, fertilized eggs were exposed to the concentration of 2.00, 4.00, 6.00, 8.00, 10.00, 15.00, 18.00, 22.00 and 25.00mg/L BPA for 72 h at 26±1℃. The results revealed that the sublethal toxicological endpoints induced by BPA were:delayed hatch> blood balk >cyst>altered axial curvature and tail malformation. The median embryo lethal concentration (LC50) after 24 h was 16.36 mg/L. We concluded that the BPA toxicity on zebrafish embryos were caused before 8h exposure and it was not the result of long-term accumulation. Therefore, BPA maybe cause altered gene expression at the early stage of zebrafish embryos. In the further studies, we will use the technology of genetic chips to look for the toxic mechanism of BPA.
文摘A series of experiments were conducted to study the major procedures in nuclear transplantation such as oocyte enucleation and activation, electrofusion and developnent of the nuclear transplant embryos in the mouse, rabbits and sheep. The important results are as follows:11. In the mouse, only 35% of the oocytes collected 15～16 h after hCG had a notable first polar body (FPb) and those without FPb were enucleated by removing cytoplasm from the PVS-wider side and the enucleation rate was similar to that in the oocytes with FPb, and the enucleation rate of removing 1/3 cytoplasm was remarkably higher than that of removing 1/4 cytoplasm. 2. Among the three fusion media tested, mannitol and sucrose solutions produced better results than M2 in electrofusion of mouse 2-cell embryos. Under favorable pulse conditions, the osmotic pressure of fusion medium had no motable effect on electrofusion, but as the conditions became so unfavorable that some embryos began to lyse, the fusion rates in hypertonie mannitol solution were significantly higher than those in isotonic or hypotonic solutions. A wide range of pulse strengths (0.31～2.04 by/ cm) and durations(10～1280 μs) were used and 100% of fusion were obtained in many cases. Optimal pulse durations were plotted for field strengths to obtain high fusion rates (96%～ 100%) in mouse2-cell embryos. 3. With one pulse of 0.45 by / cm, satisfactory results of mouse oocyte activation were obtained only when the duration increased to 160 μs or longer. The activation rate increased as the oocytes got older. Some of the oocytes ar. rested at metaphase Ⅲ after electrical stimulation and their proportion to the number of oocytes not activated increased with egg age. 4. 10% and 31% of the nuclear transplant embryos developed to morula or blastocyst stage in sheep and rabbits, respectively, with Chinese-made hormones and chemicals.
文摘Factors affecting the in vitro germination and growth of Taxus cuspidata embryos were examined. DCR medium was the best among 6 basal media tested; embryos from stage II seeds were the optimal developmental stage for in vitro germination; as the seeds approached maturity, germinability of embryos decrease. Embryos cultured in darkness tended to form callus and decrease the frequency of germination; inoculation method obviously affected frequency of embryo germination. Embryos cultured in optimal conditions developed into seedlings in 2 months.
