茶叶中酸性杂多糖的部分化学性质及降血糖活性的研究

粗老绿茶用醇提、复合纤维素酶提取、醇沉、再经弱碱性的大孔阴离子交换树脂D315柱层析,经NaCl洗脱,超滤除盐得酸性多糖ATPS。传统多糖的分离纯化一般采用价格昂贵的DEAE纤维素柱层析,很难进行工业化生产,为考察价格便宜的大孔阴离子交换树脂D315的分离纯化性能,对其分离得到的酸性茶多糖ATPS的部分化学性质进行了研究。将ATPS上DEAE52纤维素柱进一步纯化,收集DEAE52 NaCl梯度洗脱的主峰,透析,冻干,得ATPS-Ⅰ。高效凝胶渗透色谱分析发现ATPS与ATPS-Ⅰ分子量分布基本一致,气相色谱和离子色谱分析表明两者的单糖组成均以鼠李糖、阿拉伯糖、半乳糖和半乳糖醛酸为主,而且摩尔比近似。紫外光谱扫描表明ATPS不含蛋白质,红外光谱分析表明其糖苷键键型有α-型和β-型两种,单糖主要以吡喃糖苷形式存在。实验表明大孔阴离子交换树脂D315可以起到分离纯化茶多糖的作用。动物实验表明：ATPS能抑制四氧嘧啶糖尿病小鼠血糖的升高。     

大鲵皮肤粘液多糖的提取及单糖组成分析北大核心CSCD

本文对大鲵皮肤粘液多糖的提取和单糖组分进行了研究。采用水提取、碱提取、酸提取及酶提取法从大鲵皮肤粘液提取粗多糖,通过1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生高效液相色谱法分析大鲵粘液多糖的单糖组分。结果表明:碱提取、酸提取、水提取、碱性蛋白酶及酸性蛋白酶提取物的总糖含量分别为4.23%、1.54%、1.81%、3.71%、2.19%;碱提取物的单糖组分为甘露糖(Man)、葡萄糖醛酸(Glc UA)、半乳糖醛酸(Gal UA)、氨基葡萄糖(Glc N)、葡萄糖(Glc)、半乳糖(Gal);酸提取物的单糖组分为Man、Glc UA;水提取物的单糖组分为Man、Glc UA、Gal;碱性蛋白酶提取物的单糖组分为Man、Glc UA、Glc N;酸性蛋白酶提取物的单糖组分为Man、Glc UA、Glc,表明不同提取工艺得到的粘液多糖的单糖组成存在差异。本文为大鲵皮肤粘液多糖的开发利用提供了依据。     

大鲵皮肤粘液多糖的提取及单糖组成分析

本文对大鲵皮肤粘液多糖的提取和单糖组分进行了研究。采用水提取、碱提取、酸提取及酶提取法从大鲵皮肤粘液提取粗多糖,通过1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生高效液相色谱法分析大鲵粘液多糖的单糖组分。结果表明:碱提取、酸提取、水提取、碱性蛋白酶及酸性蛋白酶提取物的总糖含量分别为4.23%、1.54%、1.81%、3.71%、2.19%;碱提取物的单糖组分为甘露糖(Man)、葡萄糖醛酸(Glc UA)、半乳糖醛酸(Gal UA)、氨基葡萄糖(Glc N)、葡萄糖(Glc)、半乳糖(Gal);酸提取物的单糖组分为Man、Glc UA;水提取物的单糖组分为Man、Glc UA、Gal;碱性蛋白酶提取物的单糖组分为Man、Glc UA、Glc N;酸性蛋白酶提取物的单糖组分为Man、Glc UA、Glc,表明不同提取工艺得到的粘液多糖的单糖组成存在差异。本文为大鲵皮肤粘液多糖的开发利用提供了依据。     

姬松茸菌丝体中各组分多糖的抗肿瘤免疫活性

对深层发酵培养的姬松茸菌丝体依次采用热水、冷碱、热碱提取,得到了四种主要的多糖组分。其中冷碱提取的水不溶性多糖(CAASP)得率最高,达8.5 8g/ 10 0g干菌,且不同的多糖组分具有不同的单糖组成。其中热水提取的水溶性多糖(HWSP)及冷碱提取的水溶性多糖(CAWSP)在2 0mg/kg·d的剂量下对小鼠S180 移植瘤显示出较高的抗肿瘤活性,抑瘤率分别高达5 9.84 %和6 4 .6 6 %。同时发现在四种多糖在发挥抗肿瘤作用过程中,小鼠的脾脏指数和胸腺指数有不同程度的提高。并且各多糖活性组分在体外均具有显著的刺激脾淋巴细胞增殖的作用     

红托竹荪菌托多糖提取工艺及抗氧化降血糖活性

为利用红托竹荪菌托,采用酶解法提取菌托多糖,优化多糖提取工艺,并测定多糖分子量、单糖组成、抗氧化及降血糖活性。结果表明,最佳酶解法提取工艺为纤维素酶2.5%、果胶酶0.4%、木瓜蛋白酶1.5%,50 ℃酶解1 h,料液比1:60、提取温度80 ℃、时间3 h,该条件下多糖提取率达15.37%,比热水浸提法提高39.60%。酶解法多糖分子量为3 344 Da (Mn)、522 208 Da (Mw)、2 929 Da (Mp),主要由葡萄糖、甘露糖、葡萄糖醛酸、半乳糖和岩藻糖等组成,葡萄糖占最高,达48.82%。菌托多糖为2.0 mg/mL时,DPPH·清除率为93.83%,Fe³⁺还原能力为0.140 7,α-葡萄糖苷酶活性抑制率为54.62%、α-淀粉酶活性抑制率为56.45%,与热水浸提法相比差异极显著或显著。酶解法提取红托竹荪菌托多糖,提取率较高,具有较高的抗氧化、降血糖活性,具有推广应用价值。     

不同提取方法对软枣猕猴桃多糖单糖组成及抗氧化活性的影响

采用高温水提工艺、低温水提工艺和微波辅助工艺从软枣猕猴桃中提取得到三种多糖,依次命名为AAP-1、AAP-2和AAP-3,对三种多糖的理化性质、单糖组成和抗氧化活性进行了研究.理化性质鉴定结果表明:三种多糖均不含酚羟基及还原糖,都含有一定量的糖醛酸和蛋白质,AAP-1含有淀粉,AAP-2和AAP-3不含淀粉;单糖组成结果表明:三种多糖均由甘露糖、鼠李糖、葡萄糖醛酸、半乳糖醛酸、葡萄糖、半乳糖、阿拉伯糖7种单糖组成,其中,AAP-1葡萄糖的摩尔百分含量最高,为94.72％;AAP-2半乳糖和阿拉伯糖的摩尔百分含量较高,分别为24.75％、38.37％;AAP-3半乳糖醛酸的摩尔百分含量较高,为16.05％.抗氧化实验结果表明:AAP-1抗氧化活性最弱;AAP-3抗氧化活性最强,其清除DPPH自由基和羟基自由基的IC50分别为1.2、2.7 mg/mL.     

欧李多糖的制备、结构表征及免疫调节活性研究CSCD

欧李富含钙素,营养丰富,且具有免疫功能,研究欧李多糖的制备、结构及免疫调节活性,可为欧李深加工提供基础。本文以欧李为原料,采用水提醇沉法提取欧李多糖(Cerasus humilis polysaccharide,CHP),利用响应面法优化提取工艺。对提取的欧李多糖用DEAE-52纤维素层析柱、G-100葡聚糖凝胶柱纯化。用高效液相色谱、凝胶渗透色谱和红外光谱对欧李多糖结构表征,并测定欧李多糖的免疫调节活性。结果表明,欧李多糖最佳提取工艺条件为提取温度79℃,提取时间2 h,液料比16∶1(mL/g)。在此条件下,欧李干粉多糖得率为(32.18±0.08)%。纯化后欧李多糖主要有CHPP-1和CHPP-2两个组分,CHPP-1、CHPP-2中多糖含量分别为99.16%和99.33%。CHPP-1的单糖组成及摩尔占比为阿拉伯糖∶半乳糖醛酸∶葡萄糖=51.4∶20.29∶17.36,分子量为47.26 kDa。CHPP-2的单糖组成及摩尔占比为阿拉伯糖∶半乳糖醛酸∶葡萄糖=41.81∶28.24∶11.68,分子量为22.94 kDa。两个组分均为吡喃环型多糖。CHPP-2可显著增强巨噬细胞增殖活性,有效刺激细胞释放NO和TNF-α、IL-6及IFN-β。欧李多糖含量丰富,且具有较强的免疫调节活性。     

酶法联合闪式提取红叶李花多糖及单糖初步分析

采用酶法联合闪式提取红叶李花中多糖,对多糖进行纯化和分离,利用气相色谱-质谱(GC-MS)初步分析多糖的组成。以单因素实验为基础,以响应面设计优化确立最佳提取工艺,以DEAE-52纤维素柱和Sephadex G-150分离多糖,乙酰化后分析单糖组成。最佳提取工艺为:酶解温度为45℃,酶解时间为2h,酶用量为0.17%,闪式提取时间为3 min,液料比35倍,转速为3000 rpm。多糖得率达到13.02%。多糖由PPCS-Ⅰ和PPCS-Ⅱ两部分构成,PPCS-Ⅰ的单糖组成和比例为鼠李糖、阿拉伯糖、木糖、甘露糖和葡萄糖(摩尔比为12.11∶3.16∶7.06∶1∶4.92),PPCS-Ⅱ的单糖组成和比例为鼠李糖、木糖、甘露糖、葡萄糖和半乳糖(摩尔比为5.02∶1∶13.65∶11.76∶8.39)。     

宁夏不同地区灵武长枣果实多糖的单糖成分分析

以宁夏4个不同地区(灵武、中宁、青铜峡、银川)成熟期的灵武长枣果实为研究对象,经水提醇沉法提取,采用DEAE-cellulose52和HW-55S分离纯化,并利用GC-MS法进行多糖的单糖组成分析。结果表明:多糖提取率最高的是灵武地区,达到1.795%;分离纯化后,4个地区的长枣多糖各得到1个中性(Ju-0)和3个酸性组分(Ju-1、Ju-2、Ju-3),其中Ju-2含量最高;GC-MS分析可知灵武长枣多糖含有阿拉伯糖、鼠李糖、核糖、岩藻糖、木糖、甘露糖、半乳糖、葡萄糖、葡萄糖醛酸、半乳糖醛酸10种单糖,不含果糖,以阿拉伯糖、核糖、半乳糖和2种糖醛酸为主,木糖含量最低。各地区多糖的单糖组成、含量各不相同,从各组分来看,四个地区多糖的Ju-0和Ju-1组分组成均以阿拉伯糖、核糖、半乳糖为主,四个地区多糖的组成差异主要在于Ju-2和Ju-3组分。从各地区单糖总量来看,灵武地区是阿拉伯糖含量最高,中宁、青铜峡、银川地区以葡萄糖醛酸含量为最高。     

画眉草多糖提取及其保湿性能研究

本文以脱脂画眉草为原料,用纤维素酶超声辅助法提取多糖;经脱蛋白、脱色、DEAE-纤维素分离纯化,得到3种多糖TPS1、TPS2、TPS3,提取率分别为0.42％、0.66％、0.54％.通过高效凝胶渗透色谱(HPGPC)分析,3种多糖的分子量分别为7886 Da、8467 Da、6366 Da;高效离子色谱(HPIC)测得TPS1组成单糖为果糖,TPS2、TPS3组成单糖为阿拉伯糖、半乳糖、葡萄糖、木糖、甘露糖、果糖、核糖和一种未知糖.对多糖TPS2的保湿和吸湿性研究结果表明TPS2的保湿和吸湿能力均优于常用保湿剂甘油、聚乙二醇400、1,3-丁二醇、壳聚糖.     

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.