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大肠杆菌N—乙酰神经氨酸裂合酶基因的组成型高效表达 总被引:1,自引:0,他引:1
应用PCR技术从E.coliJM105中扩增出长约890bp的N-乙酰 酶基因,将其插入高表达载体pET28a的NcoI/BamHI痊点,转化E.coliBL21(DE3),构建高产N-乙酰神经氨酸裂合酶基因工程菌,其表达量占菌体总可溶性蛋白的76.8%,活力比宿主菌均有不同程度的提高,其中107号比宿主菌高14倍。 相似文献
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(1S,4S)—2—甲基—2,5—二氮杂二环[2.2.1]庚烷的合成 总被引:4,自引:0,他引:4
以反-4-羟-L-脯氨酸为原料,以硼氢化锌还原羧基,以二甲基甲酰胺代替吡啶在室温下进行羟基磺酰化,在甲胺水-甲苯溶液中取代环合,共经5步合成(1S,4S)-2,5-二氮杂二环「2.2.1」庚烷,5步总收率37%。 相似文献
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第四代头孢菌素—硫酸头孢噻利 总被引:9,自引:1,他引:9
对第四代注射用头孢菌素─—硫酸头孢噻利的体内外抗菌活性、药物动力学、临床等研究现状进行概述,同时和其他头孢菌素(头孢吡肟、头孢曲松、头孢他啶、头孢哌酮、头孢噻肟、头孢匹罗)作了比较。硫酸头孢噻利对甲氧西林耐药性金黄色葡萄球菌、铜绿假单胞菌优良的抗菌作用及耐酶特性使其具有广阔的应用前景。 相似文献
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本文报道无机合成法成牢利齿(二羟碳酸铝钠)的新工艺,确证其结构与文献报道的一致,并制成其散剂,考察了牢利齿及其散剂的稳定性,于室温下存放3年,外观及含量无明显变化,体外,体内药效学试验,其防,治龋齿作用优于朵贝尔氏液。 相似文献
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The radioreceptor assay using 3H-QNB as a ligand on cardiac membrane preparation and determination of pA2 and pA10 on isolated atria and ileum of guinea-pig were performed for comparing the potency of M-receptor antagonism of a new cholinolytic compound TBBB with that of HBB and atropine. Taking the potency of atropine as 1, the inhibition action of TBBB and HBB on 3H-QNB bindings to cardiac membrane preparation corresponded to 1/77 and 1/59, respectively. The antagonistic action of both in this respect was almost the same. The antagonism of inhibition induced by Ach on contractility of guinea-pig atria, however, was 1/8.9 and 1/26.5 for TBBB and HBB, respectively. The cholinolytic effect of TBBB and HBB on isolated guinea-pig ileum was 1/11.2 and 1/21,9, respectively, showing that the former is more potent to relax the spasm of gastro-intestinal smooth muscle. The mode of antagonism was believed to be competitive based on the fact that the difference of PA2 and PA10 observed was about 0.95 which was the same for all the three compounds. TBBB, which is less expensive and easier to produce, is warranted for clinical applications. 相似文献
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目的:研究复方丹酚滴丸中不同质量浓度冰片配伍丹酚酸后对丹酚酸B,紫草酸,迷迭香酸3个成分在小肠的吸收速率常数(Ka)和表观吸收系数(P_(app))的影响。方法:采用大鼠在体单向肠灌注试验考察吸收过程,以HPLC测定丹酚酸B,紫草酸和迷迭香酸的含量,流动相1%冰乙酸水溶液(A)~(~(-1))%冰乙酸甲醇溶液(B)梯度洗脱(0~10 min,10%~20%B;10~40min,20%~47%B;40~50 min,47%~70%B),检测波长286 nm,流速0.8 m L·min~(~(-1))。结果:高、中、低质量浓度冰片配伍丹酚酸后,Ka和Papp大多有所增加,其中以100 mg·L~(~(-1))冰片组的促吸收效果最优,该组丹酚酸B,紫草酸,迷迭香酸的全肠段Ka分别为不加冰片的2.31,2.33,3.38倍。结论:不同浓度冰片配伍丹酚酸后,对丹酚酸B,紫草酸和迷迭香酸在大鼠各肠段的吸收具有一定促进作用,浓度对促吸收效果有一定影响;增加冰片的浓度,促吸收作用有所提高,但当冰片到一定浓度后,促吸收作用有所减弱。 相似文献
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