胆固醇是人体重要的脂质,胆固醇水平过高可引发高胆固醇血症等疾病,3-羟基-3-甲基戊二酰辅酶A还原酶(3-hydroxy-3-methylglutaryl coenzyme A reductase,HMGCR)是催化胆固醇生物合成中的限速酶,因此HMGCR是调节胆固醇稳态的关键因素,HM...胆固醇是人体重要的脂质,胆固醇水平过高可引发高胆固醇血症等疾病,3-羟基-3-甲基戊二酰辅酶A还原酶(3-hydroxy-3-methylglutaryl coenzyme A reductase,HMGCR)是催化胆固醇生物合成中的限速酶,因此HMGCR是调节胆固醇稳态的关键因素,HMGCR在体内的调控机制十分复杂。本文从HMGCR的转录表达、降解、活性方面总结了该酶调控机制的研究进展及与相关疾病的关系。展开更多
尾巨桉（Eucalyptus urophylla×E.grandis）属于桃金娘科（Myrtaceae）桉属（Eucalyptus）速生树种之一,其油腺细胞能够产生1,8-桉叶素、β-桉叶醇和α-蒎烯等主要成分的挥发性精油。桉树精油具有疏风解热、祛湿解毒、抑菌消炎、...尾巨桉（Eucalyptus urophylla×E.grandis）属于桃金娘科（Myrtaceae）桉属（Eucalyptus）速生树种之一,其油腺细胞能够产生1,8-桉叶素、β-桉叶醇和α-蒎烯等主要成分的挥发性精油。桉树精油具有疏风解热、祛湿解毒、抑菌消炎、防腐止痒的医药功效（Ogunwande et al.,2005）;同时作为牙膏、口香糖、化妆品及食品的香精来源。因此,开发尾巨桉精油具有重要的经济价值,但工业上桉树精油产率一般为0.8%～5%,相对较低（宋永芳,1990）;而遗传代谢工程已成为提高植物次生代谢产物含量的有效手段之一。展开更多
3-羟甲基戊二酰辅酶A-还原酶(3-hydroxy-3-methylglutaryl coenzyme A reductase,HMGR)是甲羟戊酸途径的关键酶。获得芫菁体内HMGR基因信息是确定甲羟戊酸途径与斑蝥素合成相关性的基础。本研究利用RACE技术从细纹豆芫菁Epicauta manner...3-羟甲基戊二酰辅酶A-还原酶(3-hydroxy-3-methylglutaryl coenzyme A reductase,HMGR)是甲羟戊酸途径的关键酶。获得芫菁体内HMGR基因信息是确定甲羟戊酸途径与斑蝥素合成相关性的基础。本研究利用RACE技术从细纹豆芫菁Epicauta mannerheimi(Mklin)体内克隆获得HMGR基因全长cDNA序列,命名为EmHMGR(GenBank登录号为JQ690539)。该基因全长3118bp,其中5'端非翻译区178bp,3'端非翻译区414bp,开放阅读框2526bp,编码842个氨基酸。推测的蛋白质分子量为92.8kDa,理论等电点为6.0,预测分子式为C4135H6604N1098O1216S50,不稳定系数为43.37,总亲水性系数为0.091,为疏水性不稳定蛋白。序列分析发现该基因编码的蛋白与已报道的其他昆虫HMGR的氨基酸序列一致性达50%以上,而且包含HMGR_Class I保守功能域、固醇敏感多肽区及HMGR蛋白的其他保守功能位点。系统进化分析发现该基因与叶甲科昆虫HMGR基因的关系最近。本研究首次从芫菁科昆虫体内克隆获得甲羟戊酸途径的关键酶EmHMGR基因,为后期芫菁体内斑蝥素生物合成途径的研究奠定了基础。展开更多
The new room-temperature molten salt was prepared based on LiTFSI[LiNC(SO 2CF 3) 2] with OZO(C 3H 5NO 2) which were not reported in literature. Its thermal and electrochemical properties were studied by differential s...The new room-temperature molten salt was prepared based on LiTFSI[LiNC(SO 2CF 3) 2] with OZO(C 3H 5NO 2) which were not reported in literature. Its thermal and electrochemical properties were studied by differential scanning calorimetry, ac impedance spectroscopy and cyclic voltammertry respectively. The results indicated that the structure symmetry of the molecule was depressed and the extent of charges delocalization was expanded, because of introducing oxygen atom of differential electronegativity in OZO molecule. DSC analysis showed that the LiTFSI-OZO molten salt has the excellent thermal stability and its eutectic temperature is below about 223.15 K. Meanwhile, the conductivity of LiTFSI-OZO molten salt at a molar ratio of 1∶4.5 is 0.75×10 -3 S/cm at 298.15 K and 3.50×10 -3 S/cm at 333.15 K. CV analysis showed that the electrochemical window of the sample is about 4 V.展开更多
文摘胆固醇是人体重要的脂质,胆固醇水平过高可引发高胆固醇血症等疾病,3-羟基-3-甲基戊二酰辅酶A还原酶(3-hydroxy-3-methylglutaryl coenzyme A reductase,HMGCR)是催化胆固醇生物合成中的限速酶,因此HMGCR是调节胆固醇稳态的关键因素,HMGCR在体内的调控机制十分复杂。本文从HMGCR的转录表达、降解、活性方面总结了该酶调控机制的研究进展及与相关疾病的关系。
文摘尾巨桉（Eucalyptus urophylla×E.grandis）属于桃金娘科（Myrtaceae）桉属（Eucalyptus）速生树种之一,其油腺细胞能够产生1,8-桉叶素、β-桉叶醇和α-蒎烯等主要成分的挥发性精油。桉树精油具有疏风解热、祛湿解毒、抑菌消炎、防腐止痒的医药功效（Ogunwande et al.,2005）;同时作为牙膏、口香糖、化妆品及食品的香精来源。因此,开发尾巨桉精油具有重要的经济价值,但工业上桉树精油产率一般为0.8%～5%,相对较低（宋永芳,1990）;而遗传代谢工程已成为提高植物次生代谢产物含量的有效手段之一。
文摘The new room-temperature molten salt was prepared based on LiTFSI[LiNC(SO 2CF 3) 2] with OZO(C 3H 5NO 2) which were not reported in literature. Its thermal and electrochemical properties were studied by differential scanning calorimetry, ac impedance spectroscopy and cyclic voltammertry respectively. The results indicated that the structure symmetry of the molecule was depressed and the extent of charges delocalization was expanded, because of introducing oxygen atom of differential electronegativity in OZO molecule. DSC analysis showed that the LiTFSI-OZO molten salt has the excellent thermal stability and its eutectic temperature is below about 223.15 K. Meanwhile, the conductivity of LiTFSI-OZO molten salt at a molar ratio of 1∶4.5 is 0.75×10 -3 S/cm at 298.15 K and 3.50×10 -3 S/cm at 333.15 K. CV analysis showed that the electrochemical window of the sample is about 4 V.
文摘目的：探讨炎症促进四氯化碳carbon tetrachloride，CC14）所致的小鼠单纯性脂肪变性进一步脂肪集聚的分子机制。方法：12只6～8周龄C57BL／6J雄性小鼠随机分为对照组（n=6）和炎症组（n=6）。2组均CCl。皮下注射2周后，再分别给予皮下注射生理盐水或酪蛋白16周，18周后处死小鼠，收集血清及肝组织标本，称量小鼠体质量及肝质量计算肝指数评估肝脏受损情况，ELISA法检测血清炎症因子白介素-6（interleukin-6，IL-6），使用化学酶促比色法检测小鼠肝组织的脂质水平，油红O染色观察小鼠肝组织的脂质集聚J晴况，real—timePCR检测小鼠固醇调节元件结合蛋白1（sterol regulatory element binding proteins-1，SREBP-1）和3-羟基-3-甲基戊二酰辅酶A还原酶（3-Hydroxy-3-methylglutaryl—coenzyme A reductase，HMGCR）的基因表达水平，Westernblot检测SREBP-1和HMGCR的蛋白表达水平。结果：炎症组IL-6的表达比对照组明显升高（f=8．434，P=0．000）。与对照组相比，炎症组的SREBP-1和HMGCR基因的表达明显上调（t=10．612，P=0．000；t=12．749，P=-0.000），Western blot显示SREBP-1和HMGCR的蛋白表达趋势与基因一致。肝脏脂质检测显示炎症组比对照组的肝脏脂质明显升高（t=6．148，P=0．000；t=7．288。P=0．000）。肝指数提示与对照组相比，炎症组的肝指数明显升高（t=8．452，P= ．000），油红0染色显示炎症组的脂质集聚明显高于对照组。结论：炎症因子可能通过促进SREBP-1-HMGCR表达使CCL所致的小鼠脂肪变性肝细胞胆固醇内源性合成增加，加重肝脏脂质的异常集聚。
