O6-methylguanine DNA methyltransferase (O6-AT) is an enzyme for the repair of the promutagenic structure, O6-aIkylguanine, from alkylated DNA, therefore low activity of O6-AT is involved in the predisposition of tissu...O6-methylguanine DNA methyltransferase (O6-AT) is an enzyme for the repair of the promutagenic structure, O6-aIkylguanine, from alkylated DNA, therefore low activity of O6-AT is involved in the predisposition of tissues to some nitrosamines and the development of cancer. The levels of O6-AT in livers of ducks from Qidong (Qd), a high incidence area of liver cancer, and from Qingpu(Qp), a relatively low incidence area were determined in this study. The results showed that the activity of O6-AT was higher in Qp than in Qd. It suggested that some nitrosamine in Qd might be one of factors responsible for the higher incidence of ducks liver cancer, because these ducks were more sensitive to nitrosa-mine.展开更多
Gaoyou and Jinding ducks with different growth rates were selected to conduct the test, and a comparative study was carried out on the expression pattern of liver insulin-like growth factor 1 （IGF-1） mRNA and its co...Gaoyou and Jinding ducks with different growth rates were selected to conduct the test, and a comparative study was carried out on the expression pattern of liver insulin-like growth factor 1 （IGF-1） mRNA and its correlation with body weight in the early embryonic stage and hatching stage. The expression pattern of hepatic IGF-lmRNA of ducks at embryonic ages of 13, 17, 21,25, 27 and 0 -7 days after hatching were monitored by real-time fluorescent quantitative PCR. The results showed that expression of duck hepatic 1GF-1 mRNA could be detected at the embryonic age of 13. Body weight and hepatic IGF-1 mRNA expression of ducks both showed an increasing trend during the early development. The expression of hepatic IGF-1 mRNA of Gaoyou ducks at embryonic ages of 13, 21 and on the 7^th day after hatching was extremely significantly higher than that of Jinding ducks （P 〈 0.01 ）, which was consistent with the changes of daily weight gain and absolute growth rate. The changes of daily weight gain and hepatic IGF-I mRNA expression both showed extremely significant specificity of the breeds and time during the entire observation （P 〈 0.01）, and which was extremely significantly affected by the interaction of the breeds and time （P 〈 0.01）. The analysis on breeds and gender manifested that the change of body weight was consistent with that of hepatic IGF-I mRNA expression, which showed an extremely significant positive correlation （P 〈 0.01 ）. The results indicated that hepatic IGF-1 mRNA expression played an important role during the early development of ducks.展开更多
经Tris-HCl缓冲液抽提、硫酸铵分级沉淀、DEAE-Sepharose Fast Flow离子交换层析、Sephacryl S-200凝胶过滤层析,得到鸭肝蛋白酶电泳纯制品.纯化倍数为650·16倍,回收率为19·23%.经SDS-PAGE和凝胶过滤测得该酶的分子量为35kD....经Tris-HCl缓冲液抽提、硫酸铵分级沉淀、DEAE-Sepharose Fast Flow离子交换层析、Sephacryl S-200凝胶过滤层析,得到鸭肝蛋白酶电泳纯制品.纯化倍数为650·16倍,回收率为19·23%.经SDS-PAGE和凝胶过滤测得该酶的分子量为35kD.该酶在pH6·0～11·0,温度低于25℃稳定,当温度上升到55℃时活性迅速下降.该酶在pH10和60℃时达到最高活性.进一步研究得知:Cu2+离子对该酶有明显促进作用,而Mn2+却使酶几乎失活.以酪蛋白为底物,在pH10·0、37℃时测得米氏常数Km值为1·33%.展开更多
文摘O6-methylguanine DNA methyltransferase (O6-AT) is an enzyme for the repair of the promutagenic structure, O6-aIkylguanine, from alkylated DNA, therefore low activity of O6-AT is involved in the predisposition of tissues to some nitrosamines and the development of cancer. The levels of O6-AT in livers of ducks from Qidong (Qd), a high incidence area of liver cancer, and from Qingpu(Qp), a relatively low incidence area were determined in this study. The results showed that the activity of O6-AT was higher in Qp than in Qd. It suggested that some nitrosamine in Qd might be one of factors responsible for the higher incidence of ducks liver cancer, because these ducks were more sensitive to nitrosa-mine.
基金Supported by National Natural Science Foundation of China(31172194)Jiangsu Science and Technology Support Program(BE2011329)Yangzhou City Technology Support Program(20122078)
文摘Gaoyou and Jinding ducks with different growth rates were selected to conduct the test, and a comparative study was carried out on the expression pattern of liver insulin-like growth factor 1 （IGF-1） mRNA and its correlation with body weight in the early embryonic stage and hatching stage. The expression pattern of hepatic IGF-lmRNA of ducks at embryonic ages of 13, 17, 21,25, 27 and 0 -7 days after hatching were monitored by real-time fluorescent quantitative PCR. The results showed that expression of duck hepatic 1GF-1 mRNA could be detected at the embryonic age of 13. Body weight and hepatic IGF-1 mRNA expression of ducks both showed an increasing trend during the early development. The expression of hepatic IGF-1 mRNA of Gaoyou ducks at embryonic ages of 13, 21 and on the 7^th day after hatching was extremely significantly higher than that of Jinding ducks （P 〈 0.01 ）, which was consistent with the changes of daily weight gain and absolute growth rate. The changes of daily weight gain and hepatic IGF-I mRNA expression both showed extremely significant specificity of the breeds and time during the entire observation （P 〈 0.01）, and which was extremely significantly affected by the interaction of the breeds and time （P 〈 0.01）. The analysis on breeds and gender manifested that the change of body weight was consistent with that of hepatic IGF-I mRNA expression, which showed an extremely significant positive correlation （P 〈 0.01 ）. The results indicated that hepatic IGF-1 mRNA expression played an important role during the early development of ducks.
文摘经Tris-HCl缓冲液抽提、硫酸铵分级沉淀、DEAE-Sepharose Fast Flow离子交换层析、Sephacryl S-200凝胶过滤层析,得到鸭肝蛋白酶电泳纯制品.纯化倍数为650·16倍,回收率为19·23%.经SDS-PAGE和凝胶过滤测得该酶的分子量为35kD.该酶在pH6·0～11·0,温度低于25℃稳定,当温度上升到55℃时活性迅速下降.该酶在pH10和60℃时达到最高活性.进一步研究得知:Cu2+离子对该酶有明显促进作用,而Mn2+却使酶几乎失活.以酪蛋白为底物,在pH10·0、37℃时测得米氏常数Km值为1·33%.
