吸附树脂AB—8对甘草酸的吸附性能及其在提取纯化中的应用

考察了大孔吸附树脂AB-8对甘草酸的吸附性能和原液浓度pH值、流速、洗脱剂的种类对树脂吸附性能的影响。结果表明,AB-8树脂对甘草酸吸附量高,易于洗脱,分离效果较好,回收率较一般方法高,达70％～80％,纯度达90％以上。     

大孔吸附树脂分离纯化银杏中种皮总黄酮

通过静态吸附、静态解吸及吸附动力学研究,对比分析了AB-8、DM-130、S-8等三种大孔吸附树脂对银杏中种皮提取液中总黄酮的分离纯化效果,并且考察和优化了AB-8和DM-130分离纯化银杏中种皮总黄酮的工艺条件.结果表明,弱极性树脂AB-8和DM-130的吸附率分别为87.72%和86.29%、解吸率为97.52%和92.20%,是性能良好的总黄酮吸附剂; 二种树脂的静态吸附曲线变化趋势一致,6 h左右达到吸附平衡,最佳吸附条件:吸附液pH=3.0,树脂用量:吸附液=1:20,吸附温度40 ℃,洗脱剂70%乙醇;动态解吸研究显示,7倍和9倍体积洗脱剂可分别将AB-8与DM-130树脂柱吸附的总黄酮基本洗脱.在优化的工艺条件下,AB-8大孔树脂纯化可使提取物中总黄酮含量达16.3%.     

大孔吸附树脂纯化海红果黄酮工艺的研究

通过采用大孔吸附树脂对海红果黄酮粗提液的静态吸附和解吸试验,从10种大孔吸附树脂中筛选出海红果黄酮纯化的最优树脂,考察了该树脂对诲红果黄酮的静态、动态吸附与解吸性能并对吸附与洗脱的最佳条件进行了研究.结果表明:NKA-9树脂对海红果黄酮有很好的吸附和解吸性能,其最优的动态吸附工艺条件为:上样液pH值为4.0,浓度5.15 mg/mL,上样量为4 BV,流速控制在2 BV/h.最优的解吸工艺条件为:洗脱剂为80％乙醇溶液,洗脱液用量为3 BV,洗脱流速控制在1 BV/h.在此优化条件下,海红果黄酮的吸附率、解析率、收率、纯度的平均值分别达到为(79.39±0.13)％,(84.14±0.11)％,(68.20±0.15)％和(28.81 ±0.06)％ (n=5).     

AB-8大孔树脂纯化欧洲鳞毛蕨总黄酮的研究

目的:对AB-8大孔吸附树脂对欧洲鳞毛蕨总黄酮的纯化工艺条件进行了系统的研究。方法:采用静态和动态的吸附-解吸实验,利用紫外可见分光光度计测量欧洲鳞毛蕨总黄酮的含量,研究不同的工艺条件对总黄酮纯化的影响。结果:AB-8大孔树脂对欧洲鳞毛蕨总黄酮的饱和吸附量是25.53mg/g,洗脱率达到98.3%,提取液的pH值对树脂的吸附能力有很大的影响,当pH值为4.08(原液pH值)时树脂吸附能力达到最大。采用0.5mg/mL流速上样,1.2BV 30%和1BV 50%乙醇1.0 mg/mL流速洗脱可较好的分离纯化欧洲鳞毛蕨总黄酮。结论:AB-8大孔树脂是欧洲鳞毛蕨总黄酮纯化的理想吸附剂。     

大孔吸附树脂对海边月见草总黄酮的吸附及解吸特性

通过比较3种大孔吸附树脂对海边月见草(O enothera littaralisSchlect.)总黄酮的吸附能力,选择了吸附量较大且易洗脱的树脂AB-8,研究了提取液浓度、pH值对该树脂静态吸附能力的影响,以及洗脱剂种类、乙醇浓度对动态解吸能力的影响。结果表明,AB-8树脂对海边月见草总黄酮有良好的吸附纯化性能,当原液浓度为1.076mg.mL-1时,树脂达饱和吸附量36.11 mg.g-1;提取液pH值对该树脂的吸附能力影响显著,pH值达4.0~4.5时树脂吸附量最大;用60%乙醇为洗脱剂,流速为1 mL.m in-1,总黄酮的动态洗脱率达83.41%,获得的总黄酮纯度为24.13%,得率3.54%;而30%乙醇(6倍柱床体积)和50%乙醇(6倍柱床体积)组合是最佳动态洗脱剂。     

AB-8大孔树脂吸附分离红花桑寄生总黄酮的影响因子研究

AB-8大孔吸附树脂对红花桑寄生总黄酮静态吸附和动态洗脱的效果,受提取液质量浓度、pH值及环境温度、振速以及洗脱剂乙醇浓度、流速等因素影响。试验表明,提取液质量浓度和pH值对AB-8树脂的吸附效果有显著影响,其吸附分离总黄酮的工艺条件为:浓度为1.2~2.0 mg/ml、pH 3.0~4.0的红花桑寄生提取液,置于摇床上,于室温条件下振荡(振速160 r/min)吸附2~3 h,然后用5倍于树脂体积(5BV)的50%乙醇以1.5 ml/min流速进行柱上动态解吸。AB-8树脂对红花桑寄生总黄酮的饱和吸附量可达29.0 mg/g,动态洗脱率达95.0%,获得产品中黄酮纯度为46.0%,得率为5.5%。     

大孔吸附树脂纯化绿茄叶黄酮的工艺研究

研究大孔吸附树脂纯化绿茄叶黄酮粗提取物的最佳工艺。通过比较10种大孔吸附树脂纯化黄酮粗提取物的吸附及解吸性能,筛选出纯化树脂XDA-1,并考察XDA-1树脂对黄酮粗提取物的静态、动态吸附与解吸的性能。结果表明,XDA-1树脂对黄酮粗提取物纯化的最佳工艺参数:吸附平衡时间8 h,吸附浓度2.00 mg/m L,p H值3.0,温度25℃,上样流速2 BV/h;解吸平衡时间2 h,解吸剂为p H值为3.0的体积分数80%的乙醇溶液,解吸流速3 BV/h,纯化倍数2.37。该研究证实大孔吸附树脂纯化绿茄叶黄酮的方法简单可行,为绿茄叶黄酮的分离纯化提供了实验依据。     

AB-8型树脂对无患子皂苷的动态吸附与解吸性能

采用单因素实验法,以树脂的饱和吸附量、产品的得率及纯度为指标,考察各因素对动态吸附与解吸的影响,优化大孔树脂动态吸附分离无患子皂苷的工艺条件。结果表明,当pH为4.5的无患子皂苷水提液以流速1 mL/min通过高径比为5.4∶1的吸附柱时,AB-8树脂对无患子皂苷的饱和吸附量达568 mg/g;采用1.5 BV的95%乙醇以1 mL/min的流速洗脱吸附后的树脂,产品得率为83.48%、纯度达93.00%;树脂重复使用8次后其吸附解吸性能基本不变。该方法可以用于无患子皂苷的工业化分离提纯。     

大孔吸附树脂分离纯化培养基残基中虫草素

采用大孔吸附树脂分离纯化人工蛹虫草培养基残基中的虫草素,以HPLC法测定样品中虫草素含量,筛选出了适宜的大孔树脂NKA-II。研究了pH、洗脱剂乙醇体积分数等因素对该树脂吸附性能及解析性能的影响。结果表明,NKA-II型树脂纯化虫草素的最佳吸附条件为pH9,吸附流速2BV/h,该树脂对虫草素的吸附量可达到16.5mg/g。洗脱工艺条件为2.5倍树脂柱体积的50%乙醇,NKA-II大孔树脂对虫草素的解析率可达到95%以上。     

Purification of cordycepin from fermentation broth of Cordyceps militaris with macroporous resin

通过比较10种不同大孔树脂吸附蛹虫草深层发酵液中虫草素的性能,筛选出合适的大孔树脂H103,并对大孔树脂H103的吸附和解吸条件进行了考察.实验结果表明,上样吸附前调节pH值为9,上样浓度为0.2 mg·mL-1,吸附流速为2 BV h-1时,大孔树脂H103对蛹虫草深层发酵液中的虫草素有良好的吸附性能;解吸时先用去离子水洗去部分杂质,再用40％的乙醇对虫草素进行洗脱,可以得到较好的效果.     

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     

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.     

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.     

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.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

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).     

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.