银杏叶总黄酮的超声波提取法

本文通过单因素实验和正交实验,确定了超声波法提取银杏叶中黄酮类化合物的最佳提取工艺,并与常规乙醇浸提法,微波提取法作了比较研究。实验表明：超声波提取法优于常规乙醇浸提法和微波提取法。超声波法的最佳操作条件为：320W超声波功率,温度30℃,70％乙醇,在液固比15：1条件下提取10min,连续提取2次,总黄酮提取率可达94．1％。     

红枣总黄酮提取工艺

目的：采用分光光度法,以芦丁为标准品测定红枣中的总黄酮含量。方法：在提取过程中通过单因素实验分析了乙醇浓度、溶媒量、提取时间三个主要因素对提取率的影响。在单因素实验的基础上通过正交设计法进行实验,优化红枣总黄酮提取工艺条件。结果：以总黄酮含量作为考察指标,影响红枣总黄酮提取的主次因素为：乙醇浓度〉溶媒量〉提取时间,红枣中总黄酮的最佳提取工艺条件为：50%乙醇、35倍量、提取时间100min。     

正交实验法优化桦褐孔菌多酚类物质的提取工艺研究

以乙醇为提取溶剂,通过正交实验对影响桦褐孔菌多酚提取的乙醇浓度、提取时间、提取温度和料液比等因素进行探讨。结果显示,桦褐孔菌多酚的乙醇提取优化工艺参数为:乙醇的浓度为50%,料液比为1:10,温度为50℃,提取时间为45min,得到的多酚提取率可达到3.099%。用乙醇-水混合体系提取桦褐孔菌多酚是一种安全、经济、有效的方法。     

提取纯化大黄素的工艺研究

目的:为虎杖中大黄素的提取纯化工艺提供实验依据。方法:以乙醇浓度、乙醇用量、提取时间、提取次数等条件为因素,分别设计了三个水平,对大黄素的提取工艺进行正交试验。结果:大黄素的最佳提取工艺为虎杖药材加85%的乙醇回流提取3次,每次8倍量的溶剂提取1.5 h。结论:应用该提取工艺得到的大黄素的质量分数不低于10%     

乙醇浓度对提取灵芝三萜含量的影响及提取物抗前列腺癌细胞LNCaP的活性

本研究考察乙醇浓度对灵芝子实体中三萜成分提取的影响及提取物抗前列腺癌细胞LNCaP的增殖活性和迁移能力,为提取灵芝三萜时乙醇浓度的选择和灵芝抑制前列腺相关疾病产品开发提供依据。研究采用高效液相（HPLC）色谱法测定了灵芝醇提物中目前具有代表性的9种三萜的含量;并用抑制前列腺癌细胞LNCaP的细胞活性和细胞迁移能力的实验研究灵芝提取物的抗前列腺癌的作用。HPLC测定结果显示,当乙醇浓度为50%-80%时,9种灵芝三萜的含量随着乙醇浓度的升高而增大;当乙醇浓度继续升高至95%时,提取的三萜含量反而有所降低。细胞实验结果显示,4个浓度乙醇的灵芝提取物都具有良好的抑制LNCaP肿瘤细胞增殖作用和阻滞LNCaP细胞迁移能力。因此在使用乙醇提取灵芝三萜时,乙醇浓度升高有利于三萜的提取;在生产灵芝抗前列腺相关产品时,提取灵芝子实体中抗前列腺增生的活性成分时选用80%的乙醇较为适宜。     

栀子黄色素的醇提制备及其稳定性研究

通过单因素实验,考察栀子黄色素乙醇提取工艺。乙醇提取最优工艺条件为：乙醇浓度30％、液固比8：1、提取温度60℃、提取次数2次、每次1h。在此条件下,栀子黄色素、栀子苷和总三萜酸的提取率分别为1．32、110．76和94．91mg／g。     

超声波辅助双水相提取柠檬皮中的柠檬苦素

以低温烘干的柠檬皮为原料,利用超声波辅助乙醇-硫酸铵双水相体系提取柠檬皮中的柠檬苦素,通过单因素实验和正交实验考察了乙醇浓度、料液比、硫酸铵用量、超声波处理温度、处理时间、提取温度和提取时间对得率的影响。结果表明:当乙醇体积浓度为60%,料液比为1∶20 g/m L,硫酸铵用量为12 g,超声波处理温度60℃,处理时间30 min,提取温度为50℃,提取时间为3 h时,得率最高。在此条件下作了3次平行实验,平均得率可达0.3222%,而且实验重现性好。     

超声法提取虎杖色素及其稳定性的研究

用乙醇作为提取溶剂,以提取得率和色价为评价指标,通过单因素实验,探讨料液比、提取温度、超声功率、提取时间、乙醇体积分数对色素提取效果的影响;通过正交实验优化提取条件,并对提取的色素进行了稳定性考察。实验结果表明:虎杖色素的最佳提取工艺条件为乙醇体积分数80%,料液比1∶30,超声温度25℃,超声功率50 W,超声时间20 min,其中料液比为显著影响因素;虎杖色素对热、光、蔗糖、NaCl、维生素C(Vc)等因素的影响较稳定,而pH、H2O2、柠檬酸对虎杖色素稳定性影响较大。     

菊苣基生叶中总黄酮提取工艺的研究

采用分光光度法,以亚硝酸钠、硝酸铝、氢氧化钠为试剂,芦丁为对照品,乙醇回流提取菊苣基生叶中总黄酮.在提取过程中,通过单因素实验分析了乙醇浓度、回流温度、回流时间及料液比等4个主要因素对提取率的影响.在单因素的基础上,通过正交实验,得到最佳提取工艺为:乙醇浓度为70%,料液比1:40,回流温度80℃,回流时间为2h.实验结果可靠,方法简便,最佳条件适合批量生产中该药材的提取.     

响应面法优化毒三素链霉菌中利普司他汀的提取工艺

采用响应面法对毒三素链霉菌提取工艺进行优化。首先确立乙醇为最佳的溶剂。以利普司他汀提取收率为指标,以乙醇为浸提溶剂,对料液比、乙醇体积分数、浸提时间、浸提温度和浸提次数进行单因素实验。在此基础上,选取料液比、乙醇体积分数、浸提时间为自变量,采用Box-Behnken设计的方法,研究各自变量及其交互作用对利普司他汀提取收率的影响。结果表明:毒三素链霉菌中利普司他汀的最佳提取工艺条件为液料比6.32∶1 m L/g、乙醇体积分数95%、浸提时间3.61 h。在此条件下,利普司他汀提取收率的预测值为83.35%,实验验证值为84.50%,相对误差为1.36%。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.