拉曼技术在药物逆向工程中的应用

逆向工程以目标产品进行逆向分析及研究,是仿制药开发过程中的一个重要环节,在目前的仿制药一致性评价中发挥显著功效。 尽管物理、化学方法众多,但原研制剂的逆向工程分析仍然极具挑战、极其耗时。逆向工程的最终目的不仅是确定原研制剂中所有可能 的化学成分,还要深入揭示其制剂原则和药物释放机制。而如何高效合理地应用各种分析技术,是深入了解原研药的第一步。文章概述 了一种光谱技术——拉曼光谱在药物逆向分析工程中的实用性,特别介绍在某些情况下,当其他常用固态分析技术如 X 射线粉末衍射、 差示扫描量热法等不适用时,拉曼光谱对原研制剂中药物活性成分(API)晶型的鉴定。文章通过对拉曼光谱在某些特定条件下应用的具 体案例的演示,展示了分子振动相关光谱分析手段在药物逆向分析工程中的应用前景。     

基因工程技术优化透明质酸生产的研究进展

透明质酸是由葡萄糖醛酸和N-乙酰葡萄糖胺组成的双糖单位聚合而成的直链酸性粘多糖,在医药、化妆品、食品等领域拥有庞大的市场。传统研究通过优化发酵参数改善透明质酸的生产虽然取得了显著成效,但也趋于上限,加之天然生产菌株固有的发酵培养基成本高、具有一定致病性等等的劣势也日益显著。随着分子生物学技术的迅速发展以及对透明质酸合成相关基因研究的不断深入,研究重点逐渐转向利用基因工程技术构建高产、安全、具有特定分子量的透明质酸工程菌株。以下就有关透明质酸生产菌株基因工程改造的策略及研究进展进行概述和展望。     

The properties of human body phantoms used in calculations of electromagnetic fields exposure by wireless communication handsets or hand-operated industrial devices

According to international guidelines, the assessment of biophysical effects of exposure to electromagnetic fields (EMF) generated by hand-operated sources needs the evaluation of induced electric field (E _in) or specific energy absorption rate (SAR) caused by EMF inside a worker's body and is usually done by the numerical simulations with different protocols applied to these two exposure cases. The crucial element of these simulations is the numerical phantom of the human body. Procedures of E _in and SAR evaluation due to compliance analysis with exposure limits have been defined in Institute of Electrical and Electronics Engineers standards and International Commission on Non-Ionizing Radiation Protection guidelines, but a detailed specification of human body phantoms has not been described. An analysis of the properties of over 30 human body numerical phantoms was performed which has been used in recently published investigations related to the assessment of EMF exposure by various sources. The differences in applicability of these phantoms in the evaluation of E _in and SAR while operating industrial devices and SAR while using mobile communication handsets are discussed. The whole human body numerical phantom dimensions, posture, spatial resolution and electric contact with the ground constitute the key parameters in modeling the exposure related to industrial devices, while modeling the exposure from mobile communication handsets, which needs only to represent the exposed part of the human body nearest to the handset, mainly depends on spatial resolution of the phantom. The specification and standardization of these parameters of numerical human body phantoms are key requirements to achieve comparable and reliable results from numerical simulations carried out for compliance analysis against exposure limits or within the exposure assessment in EMF-related epidemiological studies.     

Engineering the specificity of Streptococcus pyogenes sortase A by loop grafting

Sortases are a group of enzymes displayed on the cell-wall of Gram-positive bacteria. They are responsible for the attachment of virulence factors onto the peptidoglycan in a transpeptidation reaction through recognition of a pentapeptide substrate. Most housekeeping sortases recognize one specific pentapeptide motif; however, Streptococcus pyogenes sortase A (SpSrtA WT) recognizes LPETG, LPETA and LPKLG motifs. Here, we examined SpSrtA's flexible substrate specificity by investigating the role of the β7/β8 loop in determining substrate specificity. We exchanged the β7/β8 loop in SpSrtA with corresponding β7/β8 loops from Staphylococcus aureus (SaSrtA WT) and Bacillus anthracis (BaSrtA WT). While the BaSrtA-derived variant showed no enzymatic activity toward either LPETG or LPETA substrates, the activity of the SaSrtA-derived mutant toward the LPETA substrate was completely abolished. Instead, the mutant had an improved activity toward LPETG, the preferred substrate of SaSrtA WT.     

余甘子总黄酮超声波辅助提取工艺的优化

以余甘子干粉为材料,利用超声波辅助提取余甘子总黄酮。单因素试验分析液料比、乙醇浓度、超声时间、超声功率对余甘子总黄酮提取率的影响,在此基础上,利用响应面分析法对提取工艺进行优化。结果表明,余甘子总黄酮最佳提取条件为：液料比82:1(V/W)、乙醇浓度45%、超声时间41 min、超声功率210 W,在此条件下余甘子总黄酮的实际提取率为6.12%。     

微波协同酶法提取平菇柄多糖的工艺研究

为优化微波协同酶法提取平菇柄多糖的工艺条件,在单因素试验的基础上,选择提取时间、微波功率以及液料比为自变量,多糖得率为响应值,采用中心组合设计的方法,研究各自变量及其交互作用对多糖得率的影响。利用响应面分析方法,模拟得到二次多项式回归方程的预测模型,并确定平菇柄多糖提取工艺的最佳条件为:微波功率420 W,提取时间8 min,液料比55:1,在此条件下,最大得率达到6.05%。