羧甲基茯苓聚糖的制备及性质研究

作者采用水媒法和溶媒法,分别将茯苓聚糖直接羧甲基化,得到了具有抗肿瘤活性的羧甲基茯苓聚糖,并对产物进行了IR、~(13)CNMR分析。     

羧甲基茯苓多糖体外抗氧化活性研究

目的：比较不同浓度洗脱液洗脱得到的羧甲基茯苓多糖的抗氧化活性。方法：以茯苓为原料提取茯苓多糖,进行羧甲基取代反应,分离和纯化得到了均一性羧甲基茯苓多糖CMP-1、CMP-2、CMP-3、CMP-4,通过测定还原能力、DPPH自由基清除率、羟基自由基清除率、超氧阴离子自由基清除率比较其体外抗氧化活性。结果：羧甲基茯苓多糖均表现出与浓度正相关的体外抗氧化活性,其中CMP-4具有相对更强的体外抗氧化活性。结论：所得羧甲基茯苓多糖样品具有不同的体外抗氧化能力,随着洗脱液浓度增加,抗氧化活性增强。     

二次碱化法制备羧甲基茯苓多糖

本研究采用二次碱化新工艺制备了水溶性羧甲基茯苓多糖,并对新旧工艺进行了比较。结果表明,使用改进的新工艺完全可以制备出质量符合要求的产品。     

羧甲基茯苓多糖的制备及体内抗肿瘤作用的实验研究

目的 :探讨羧甲基茯苓多糖的制备方法及体内抗肿瘤作用。方法 :选择性氧化茯苓菌发酵液得羧甲基茯苓多糖 ,检测三个剂量的羧甲基茯苓多糖 (2 mg/ ml、4mg/ ml、6mg/ ml)对 H2 2 荷瘤小鼠淋巴细胞转化率和 NK细胞杀伤活性以及血清中 TNF-α含量的影响。结果 :羧甲基茯苓多糖三个剂量组均可提高荷瘤小鼠的淋巴细胞转化率和 NK细胞杀伤活性 ,与生理盐水组相比差异有显著性 (P<0 .0 5) ,中剂量组抗肿瘤的效果显著 ,与其他两组相比差异有显著性 (P<0 .0 5) ;羧甲基茯苓多糖三个剂量组均可提高荷瘤小鼠血清中 TNF-α的含量 ,与生理盐水组相比差异有显著性 (P<0 .0 5) ,但三个剂量组之间比较差异无显著性 (P<0 .0 5)。结论 :羧甲基茯苓多糖可改善荷瘤小鼠的免疫功能 ,具有抗肿瘤作用 ,且功效与作用剂量间有一定的关系 ,在最佳剂量时活性最高     

不同碳氮源对糙皮侧耳木质纤维素酶活性的影响

以糙皮侧耳Pleurotus ostreatus为材料,研究简单碳氮源及木质素纯品诱导条件对其木质纤维素酶活性的影响。结果表明,不同的碳源培养基和氮源培养基对糙皮侧耳漆酶活性、羧甲基纤维素酶活性和木聚糖酶活性均具有极显著的影响（P<0.001）,且对糙皮侧耳菌丝生物量也有极显著的影响（P<0.001）。以蔗糖作主要碳源诱导物时,有利于提高糙皮侧耳漆酶活性;以果糖作主要碳源诱导物时,有利于提高糙皮侧耳羧甲基纤维素酶活性和菌丝生物量的积累;以葡萄糖作主要碳源诱导物时,有利于提高糙皮侧耳木聚糖酶活性。以酵母浸粉作主要氮源诱导物时,有利于提高糙皮侧耳漆酶活性和菌丝生物量的积累;以硝酸钾作为主要氮源诱导物时,有利于提高糙皮侧耳羧甲基纤维素酶活性;以硫酸铵作为主要氮源诱导物时,有利于提高糙皮侧耳木聚糖酶活性。碱性木素的存在,有利于提高糙皮侧耳漆酶活性,但不利于菌丝生物量的积累。与此同时,碱性木素的存在对糙皮侧耳羧甲基纤维素酶和木聚糖酶活性并没有促进作用。     

一步法制备羧甲基茯苓多糖的工艺研究

本实验对在有机溶剂中一步法半合成羧甲基茯苓多糖的合成条件进行了研究。结果表明,乙醇是作为羧甲基化反应的合适介质。反应温度提高能加快反应速度;反应时间延长能提高取代度。茯苓多糖葡萄糖当量与氢氧化钠和一氯乙酸的摩尔比调配适当,能减少副产物羟乙酸钠的产生。     

固氮类芽孢杆菌YUPP-5中环糊精糖基转移酶基因的克隆与功能分析

从魔芋根际分离的固氮类芽孢杆菌Paenibacillus azotofixans YUPP-5对多种β-1,4糖苷键连接的多糖具有水解作用。通过构建该菌的fosmid文库,克隆到2 157 bp的基因片段,编码环糊精糖基转移酶。大肠杆菌中表达此酶,能降解葡甘聚糖、羧甲基纤维素钠盐、几丁质、木聚糖等多种β-1,4糖苷键连接的多糖,同时该酶还能以葡甘聚糖为底物生成β-1,4糖苷键连接的环糊精,而文献报道这种酶仅能利用α-1,4糖苷键连接的淀粉为底物生成环糊精;并展示了环糊精糖基转移酶的一些新功能。     

中药有效成分在干扰素生物技术实验与临床研究中的应用

中草药是我国的宝贵财富,刺五加、茯苓、银耳、云芝等均具有抗菌、抗病毒、免疫调节和抗肿瘤作用。而干扰素(IFN)的三种类型(α、β、γ)也具有这种生物学效应,为了研究上述补气类中药有效成分这一药理效应的物质基础和分子介质,本文用刺五加甙及其多糖,羧甲基茯苓多糖、银耳多糖、云芝糖肽等中药有效成分进行 了干扰素促诱生效应的研究。     

羧甲基茯苓多糖的水媒法制备及其免疫活性研究

羧甲基茯苓多糖carboxymethyl-pachymaran（CMP）具有良好的免疫调节活性,传统方法使用两步工序在醇相体系中制得,有机溶剂消耗大、成本高。本研究报道一种新制备方法,将提取茯苓多糖以及茯苓多糖与氯乙酸的醚化反应整合在一个碱液体系中完成。动物实验表明,新方法制备的CMP能提高环磷酰胺诱导的免疫低下小鼠的细胞免疫和体液免疫功能,对S180肉瘤具有抑制活性。经口急性毒理结果显示CMP属于实际无毒物质,适合于功能性食品和保健食品开发应用。     

生物化学教学中“聚糖与医学”相关内容的引入与探讨

聚糖在生理、病理中作用机制的阐释使聚糖与医学的相关性得到重视,聚糖结构的变化常与疾病直接相关。生物化学作为生物相关专业的重要基础课程,其教学内容也应该引入新的科研成果,与时俱进。目前各个版本的生物化学课本并未涉及“聚糖与医学”相关知识,本文对“聚糖与医学”相关内容在生物化学教学中的引入进行了探讨,并对肿瘤等疾病中的异常聚糖以及聚糖在疾病治疗和诊断中的应用等引入内容进行了具体阐述。“聚糖与医学”相关内容的引入符合“基础与临床”相结合的教学理念,有利于增加学生对科研前沿的了解,提升学生的科研素养和核心竞争力。     

硫酸化茯苓多糖急性毒性实验研究

按10、8、6.4、5.12、4.1g/kg体重剂量的硫酸化茯苓多糖(SP)分别灌胃给药,通过观察小鼠的活动和急性毒性反应,记录小鼠的死亡数,用综合计算法计算半数致死量(LD50)等相关数据.结果表明硫酸化茯苓多糖灌胃给药的LD50为7.358/kg,LD50的95%平均可信限为(7.358±0.894)g/kg,属低毒性物质.该研究为开发应用硫酸化茯苓多糖新药提供科学的药理学依据.     

茯苓多糖结构修饰及其与AA相互作用机理的研究

将茯苓多糖硫酸化得到硫酸化茯苓多糖(SP),应用光谱法研究了SP与天青A(AA)相互作用机理,并通过理论模型测得SP与AA最大结合数N=62,结合常数K=3.703×105。考察了反应体系中AA/SP摩尔比、NaCl、乙醇、羟丙基β环糊精以及TritonX 100对相互作用的影响。并对SP与AA相互作用机理提出了合理的解释。     

亚甲蓝与多聚阴离子化合物结合反应的研究

对光谱探针亚甲蓝(MB)分别与硫酸化茯苓多糖(SP)、硫酸软骨素(CS)、透明质酸(HA)等多聚阴离子化合物相互作用的吸收光谱进行了比较研究,探讨了CS等多聚阴离子化合物与MB相互作用机理及其与MB结合的功能基团,计算了MB与SP、CS最大结合数分别为54和73。研究结果表明MB与多聚阴离子化合物的磺酸基发生明显的结合反应,与羧基不能发生明显的结合反应,多聚阴离子化合物与MB结合的功能基团是磺酸基。     

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.