Present investigation was carried out to study the factors which affect milk production of dairy cattle in Labuduwa, Rathgama and Yakkalamulla veterinary ranges in Galle district, Sri Lanka. Breed type of cattle, inse...Present investigation was carried out to study the factors which affect milk production of dairy cattle in Labuduwa, Rathgama and Yakkalamulla veterinary ranges in Galle district, Sri Lanka. Breed type of cattle, insemination method, sex of the calves, milk production of mother cows, rearing methods and ectoparasitic tick infestations were studied. The studied cattle were belonged to cross breeds of Jersey, Friesian, Sahiwal and AFS （Australian friesian sahiwal）and Jersey was the most common breed. Sahiwal and AFS breeds tend to produce more male calves under artificial insemination. The milk production of mother cows reared under semi intensive management system was high （p 〈 0.05）. In addition, results revealed that the milk production of artificially inseminated mother cows was higher than that of the naturally bred mother cows （p 〉 0.05）. Boophillus decolaratus was the only tick species present on studied calves with low percentage abundance （14.54%） of male ticks compared to that of female ticks （85.45%）. Tick abundance was high in calves reared under free range management system. The tick abundance was high in Labuduwa range than Rathgama range （p 〉 0.05）. According to the findings of the present study, the effect of the cattle management system has considerable impacts on milk production and tick infestations of dairy cattle in studied veterinary ranges in Galle district.展开更多
During embryonic development, pluripotent endoderm tissue in the developing foregut may adopt pancreatic fate or hepatic fate depending on the activation of key developmental regulators. Transdifferentiation occurs be...During embryonic development, pluripotent endoderm tissue in the developing foregut may adopt pancreatic fate or hepatic fate depending on the activation of key developmental regulators. Transdifferentiation occurs between hepato- cytes and pancreatic cells under specific conditions. Hepatocytes and pancreatic cells have the common endodermal progenitor cells. In this study we isolated hepatic stem/progenitor cells from embryonic day (ED) 12-14 Kun-Ming mice with fluorescence-activated cell sorting (FACS). The cells were cultured under specific conditions. The cultured cells deploy dithizone staining and immunocytochemical staining at the 15th, 30th and 40th day after isolation. The results indicated the presence of insulin-producing cells. When the insulin-producing cells were transplanted into alloxan- induced diabetic mice, the nonfasting blood glucose level was reduced. These results suggested that fetal liver stem/ progenitor cells could be converted into insulin-producing cells under specific culture conditions. Fetal liver stem/ progenitor cells could become the potential source of insulin-producing cells for successful cell transplantation therapy strategies of diabetes.展开更多
In this paper, populus xeuramericana cv. Guariento was transformed with bean chitinase by Agrobacterium tumefaciens-mediated leaf disc method. Firstly, the leaf explants were pre-cultured at 25℃ for 2d. Secondly, the...In this paper, populus xeuramericana cv. Guariento was transformed with bean chitinase by Agrobacterium tumefaciens-mediated leaf disc method. Firstly, the leaf explants were pre-cultured at 25℃ for 2d. Secondly, they were infected in Agrobacterium tumefaciens suspension （OD600=0.5） for 20 rain, then were co-cultured for 3d in the dark. Thirdly, the explants were transferred to the selection culture medium （containing Kanamycin 40 mg.L^-1 and Cefotaxime Sodium 800 mg-L1） and incubated at 25℃ until resistance buds formed. Chitinase activity was determined for the positive plants by PCR and PCR-Southern blot hybridization analysis. And, chitinase activity of positive plants was significantly higher than that of control plant, and the highest ratio of activity of NO.4 to that of control was 3.41. It showed that bean chitinase gene had been expressed in the plant genome.展开更多
文摘Present investigation was carried out to study the factors which affect milk production of dairy cattle in Labuduwa, Rathgama and Yakkalamulla veterinary ranges in Galle district, Sri Lanka. Breed type of cattle, insemination method, sex of the calves, milk production of mother cows, rearing methods and ectoparasitic tick infestations were studied. The studied cattle were belonged to cross breeds of Jersey, Friesian, Sahiwal and AFS （Australian friesian sahiwal）and Jersey was the most common breed. Sahiwal and AFS breeds tend to produce more male calves under artificial insemination. The milk production of mother cows reared under semi intensive management system was high （p 〈 0.05）. In addition, results revealed that the milk production of artificially inseminated mother cows was higher than that of the naturally bred mother cows （p 〉 0.05）. Boophillus decolaratus was the only tick species present on studied calves with low percentage abundance （14.54%） of male ticks compared to that of female ticks （85.45%）. Tick abundance was high in calves reared under free range management system. The tick abundance was high in Labuduwa range than Rathgama range （p 〉 0.05）. According to the findings of the present study, the effect of the cattle management system has considerable impacts on milk production and tick infestations of dairy cattle in studied veterinary ranges in Galle district.
基金This work was supported by National Natural Science Foundation of China(No.3024007)Beijing Natural Science Foundation(No.5042011)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry to Ren Qing FENG.
文摘During embryonic development, pluripotent endoderm tissue in the developing foregut may adopt pancreatic fate or hepatic fate depending on the activation of key developmental regulators. Transdifferentiation occurs between hepato- cytes and pancreatic cells under specific conditions. Hepatocytes and pancreatic cells have the common endodermal progenitor cells. In this study we isolated hepatic stem/progenitor cells from embryonic day (ED) 12-14 Kun-Ming mice with fluorescence-activated cell sorting (FACS). The cells were cultured under specific conditions. The cultured cells deploy dithizone staining and immunocytochemical staining at the 15th, 30th and 40th day after isolation. The results indicated the presence of insulin-producing cells. When the insulin-producing cells were transplanted into alloxan- induced diabetic mice, the nonfasting blood glucose level was reduced. These results suggested that fetal liver stem/ progenitor cells could be converted into insulin-producing cells under specific culture conditions. Fetal liver stem/ progenitor cells could become the potential source of insulin-producing cells for successful cell transplantation therapy strategies of diabetes.
基金This work was supported by Heilongjiang Key Technologies R＆D Programme （No. GB06B303-4） and Heilongjiang Natural Science Foundation（No. ZJN04-0101）.
文摘In this paper, populus xeuramericana cv. Guariento was transformed with bean chitinase by Agrobacterium tumefaciens-mediated leaf disc method. Firstly, the leaf explants were pre-cultured at 25℃ for 2d. Secondly, they were infected in Agrobacterium tumefaciens suspension （OD600=0.5） for 20 rain, then were co-cultured for 3d in the dark. Thirdly, the explants were transferred to the selection culture medium （containing Kanamycin 40 mg.L^-1 and Cefotaxime Sodium 800 mg-L1） and incubated at 25℃ until resistance buds formed. Chitinase activity was determined for the positive plants by PCR and PCR-Southern blot hybridization analysis. And, chitinase activity of positive plants was significantly higher than that of control plant, and the highest ratio of activity of NO.4 to that of control was 3.41. It showed that bean chitinase gene had been expressed in the plant genome.
