诃子中总多酚含量的测定及其超声提取工艺的研究

目的：利用超声波辅助法提取诃子中总多酚。方法：考察了超声波的提取时间、乙醇浓度、料液比三个单因素对多酚提取率的影响,并在单因素实验基础上进行正交实验。结果：确立了诃子中总多酚的最佳工艺条件为：60%乙醇;料液比为1：20;超声提取60min。总多酚得率为13.27%。结论：此提取方法能够避免多酚在高温下的分解,极大地缩短了提取时间。     

核桃楸叶片中总黄酮的最佳提取工艺研究

利用超声波法对核桃楸叶片中总黄酮的提取工艺进行了研究,在单因素试验的基础上,采用正交试验法,确立最佳提取条件,考察乙醇浓度、提取温度、液料比和提取时间对核桃楸叶片总黄酮提取率的影响。结果表明：超声波法辅助提取核桃楸叶片总黄酮的最适工艺参数是浸提剂乙醇浓度为70%,提取温度为50℃,液料比为20：1,提取时间为20 min,且总黄酮提取率可达4.458%。     

响应面法优化细果角茴香中总黄酮的超声提取条件

采用响应面法优化超声波辅助提取细果角茴香中总黄酮的工艺研究。在单因素试验的基础上,选择超声时间、乙醇浓度、料液比为自变量,以总黄酮的提取率为响应值,进行Box-Behnken中心组合实验设计,采用响应面法(RSM)评估了这些因素对总黄酮提取率的影响。结果表明:超声波法辅助提取细果角茴香中总黄酮的最佳工艺条件为液料比33 mL/g,乙醇浓度为58%,提取时间为34.5 min。在此条件下,总黄酮的提取率达1.525%。     

莲子心总黄酮的超声波萃取工艺研究

研究了超声波萃取法从莲子心中提取总黄酮的最佳工艺。通过单因素控制法和正交试验,以乙醇为溶剂,总黄酮提取率为考察指标,在超声波辅助下研究了乙醇浓度、提取时间、料液比和提取温度对总黄酮提取率的影响。结果表明影响莲子心中总黄酮提取率的主要因素是乙醇的浓度,其次依次为提取温度、料液比、超声波萃取时间;提取的最佳条件是:乙醇的浓度为60%,提取温度是70℃,料液比为1:24,超声波萃取时间为30 min,此条件下得到的总黄酮的提取率是10.86 mg/g。     

响应面法优化蕤核叶片总黄酮提取工艺

采用超声波辅助提取的方法从蕤核叶片中提取总黄酮.利用响应面法(RSM法)研究了超声提取时间、乙醇浓度、液固比、提取温度等因素对总黄酮得率的影响,确定了超声波辅助提取蕤核叶片总黄酮的最佳工艺参数.结果表明,超声波辅助提取蕤核叶片总黄酮的最佳工艺务件为:超声时间50.1 min,乙醇浓度59.5%,液料比24.9:1,提取...     

响应面法优化余甘叶中黄酮提取工艺

以余甘叶为试材,利用超声波辅助提取余甘叶黄酮,研究料液比、乙醇浓度、超声时间、超声功率对黄酮提取率的影响,并在单因素试验的基础上,通过响应面分析法优化提取工艺。结果表明,余甘叶中黄酮最佳超声提取条件为：料液比1∶73、乙醇浓度50%、超声时间30 min、超声功率210 W,在此条件下黄酮实际提取率为19.51%。     

落叶松树皮原花青素提取工艺的研究

本文考察了落叶松树皮原花青素的料液比、乙醇浓度、提取温度、超声时间对原花青素提取效果的影响。采用正交实验,对提取工艺进行了优化。结果表明各因素对原花青素的提取效果的影响程度为提取温度>提取时间>乙醇浓度>料液比。从而确定落叶松树皮中原花青素的最佳工艺条件为:提取温度为35℃,提取时间为0.5 h,乙醇浓度为50%,料液比为1∶15(g/mL)。     

正交实验优选月腺大戟根总黄酮的提取工艺

目的：研究月腺大戟根中总黄酮类化合物的提取工艺,为研发新型植物源农药提供理论基础。方法：采用索氏提取法对月腺大戟根总黄酮进行提取,以乙醇体积分数、提取时间、提取温度、料液比为实验因素,以提取的总黄酮含量为指标,对提取工艺进行考察,确定最佳提取条件。结果和结论：根总黄酮提取的优化条件为：提取时间2h,提取温度70℃,料液比1：40,乙醇浓度50％;影响提取的主次顺序为：料液比〉提取时间〉乙醇浓度〉提取温度;其中料液比和提取时间是影响根总黄酮提取效果的显著因素。     

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%。     

响应面优化-超声提取黄姜中总黄酮工艺研究

目的:利用响应面法对黄姜总黄酮的提取工艺进行优化.方法:在单因素的基础上以超声功率、超声时间、料液比、乙醇浓度为响应因素,黄姜总黄酮的提取率为响应值,根据中心组合实验原理,采用四因素三水平的响应面分析法.结果:确定提取最佳工艺参数为超声时间29.53 min、超声功率为400.76w、料液比为1:42.19、乙醇浓度为79.60％,在此条件下总黄酮提取率的预测值为11.15 (mg/g).结论:考虑到实际操作的问题,将提取最佳工艺参数修正为超声时间30 min、超声功率400w、料液比1:40、乙醇浓度80％,进行3次平行试验,结果总黄酮提取率为11.09 mg/g,绝对误差为0.057％,说明实验结果与模型吻合很好.     

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.