Quantitative regulation of the thermal stability of enveloped virus vaccines by surface charge engineering to prevent the self-aggregation of attachment glycoproteins

The development of thermostable vaccines can relieve the bottleneck of existing vaccines caused by thermal instability and subsequent poor efficacy, which is one of the predominant reasons for the millions of deaths caused by vaccine-preventable diseases. Research into the mechanism of viral thermostability may provide strategies for developing thermostable vaccines. Using Newcastle disease virus (NDV) as model, we identified the negative surface charge of attachment glycoprotein as a novel determinant of viral thermostability. It prevented the temperature-induced aggregation of glycoprotein and subsequent detachment from virion surface. Then structural stability of virion surface was improved and virus could bind to and infect cells efficiently after heat-treatment. Employing the approach of surface charge engineering, thermal stability of NDV and influenza A virus (IAV) vaccines was successfully improved. The increase in the level of vaccine thermal stability was determined by the value-added in the negative surface charge of the attachment glycoprotein. The engineered live and inactivated vaccines could be used efficiently after storage at 37°C for at least 10 and 60 days, respectively. Thus, our results revealed a novel surface-charge-mediated link between HN protein and NDV thermostability, which could be used to design thermal stable NDV and IAV vaccines rationally.     

Cost-effectiveness evaluation of different control strategies for Clonorchis sinensis infection in a high endemic area of China: A modelling study

Clonorchiasis is an important food-borne parasitic disease caused by Clonorchis sinensis infection. The evaluation of long-term cost-effectiveness of control strategies is important for disease control and prevention. The present study aimed to assess the cost-effectiveness of the three recommended strategies (i.e., WHO, Chinese and Guangdong strategies) and different combinations of commonly used measures (i.e., preventive chemotherapy, information, education, and communication (IEC) and environmental improvement) on clonorchiasis. The study area, Fusha town in Guangdong Province, was a typical high endemic area in China. The analysis was based on a multi-group transmission model of C. sinensis infection. We set the intervention duration for 10 years and post-intervention period for 50 years. The corresponding costs and DALYs were estimated. Strategies with incremental cost-effectiveness ratios (ICERs) less than 1/5 of the willingness-to-pay threshold were identified as highly cost-effective strategies. The optimal control strategy was obtained using the next best comparator method. The ICERs of Guangdong strategy were $172 (95% CI: $143-$230) US for praziquantel and $106 (95% CI: $85-$143) US for albendazole, suggesting the highest cost-effectiveness among the three recommended strategies. For praziquantel, 470 sets of control strategies were identified as highly cost-effective strategies for achieving infection control (prevalence<5%). The optimal strategy consisted of chemotherapy targeted on at-risk population, IEC and environmental improvement, with coverages all being 100%, and with the ICER of $202 (95% CI: $168-$271) US. The results for transmission control (prevalence<1%) and albendazole were obtained with the same procedures. The findings may help to develop control policies for C. sinensis infection in high endemic areas. Moreover, the method adopted is applicable for assessment of optimal strategies in other endemic areas.     

猪肌肉的转录组学研究进展

猪在中国的畜牧业及人类疾病的研究中有着不可或缺的作用,一方面猪提供了人类日常所需的肉类食物,另一方面在人类的器官移植方面的研究甚为广泛.因此,对于猪的各方面的研究都较为广泛,但在肌肉mRNA转录组方面涉及不深.转录组包括编码RNA和非编码RNA,根据测序结果,通过对不同品种的同位基因进行比较,用来分析相互之间的差异,进...     

现代系统生物技术与图式遗传学

基因组程序化表达调控与生物体形态结构发生的相互对应是图式遗传学和系统生物技术研究复杂生物系统的核心。基因-蛋白质表达与神经-内分泌信号,构成生物系统发生演变的双向调控过程是生物信息控制系统的结构、功能和演变的基础。细胞信号传导与基因差异表达调控是从基因、细胞到器官的细胞动力学转换系统,是基因、蛋白质、脂类等生物高分子相互作用与细胞再生、分化、迁移、凋亡的程序化调控节律,也就是基因定位图谱-细胞定位图谱的基因组-蛋白质组与生物体的细胞节律-形态的发生转换过程。     

海枣曲霉β—D—岩藻糖苷酶的研究

Although beta-D-fucosidase (beta-D-fucoside fucohydrolase, EC 3.2.1.38) has been isolated from various sources, the identity of this enzyme is still not settled. We have purified a specific beta-D-fucosidase in electrophoretically homogeneous form crude extracts of Aspergillus phoenicis by polyethyleneglycol 6000-phosphate buffer aqueous two-phase separation, and successive chromatography on DEAE-Sephadex A-50, hydroxyapatite and Sephadex G-100 columns. The molecular weight of the enzyme was estimated to be 57000 by SDS-polyacrylamide gel electrophoresis and 50000 to 60000 by gel filtration on Sephadex G-100. The enzyme showed optimum coside were 2.4mmol/L, and 1.28 mumol min-1 the pH range 5.5-6.5 and below 35 degrees C. The Km and the Vmax values for pNP-beta-D-fucoside were 2.4mmol/L, and 1.28 mumol.min-1.mg-1 respectively. The enzyme was strongly inhibited by sulfhydryl group reagents, PCMB-NEM and iodoacetate. It was also inhibited by EDC, DEP and NBS. Thus, -SH, -COOH groups, histidyl and tryptophyl residues were essential for enzyme activity. The purified beta-D-fucosidase showed high specificity toward p-nitrophenyl beta-D-fucoside. The enzyme was inhibited by D-fucose and D-fucono-gamma-lactone, but not by D-galactose, D-galactono-gamma-lactone, D-glucose or D-glucono-gamma-lactone; the latter compounds are specific inhibitors of beta-D-galactosidase and beta-D-glucosidase respectively. Thus, this enzyme is the most strictly specific beta-D-fucosidase when compared with those previously reported.     

华癸中慢生根瘤菌7653R 3个脂质转运蛋白基因的克隆、突变及共生表型北大核心CSCD

【目的】脂类转移家族蛋白基因编码一类参与脂类转运及代谢的蛋白。本研究旨在构建华癸中慢生根瘤菌3个脂质转运家族蛋白基因的突变株,检测及分析突变体与紫云英共生条件下的表型及功能。【方法】利用生物信息学分析与预测转脂蛋白的结构特征及功能,采用荧光定量技术检测目标基因在自生和共生条件下的表达特性,通过插入突变技术构建目标基因突变株,并进行植物盆栽实验考察其共生表型。【结果】MCHK-5577、MCHK-2172和MCHK-2779基因编码蛋白属于START/RHO alpha_C/PITP/Bet_v1/Cox G/Cal C(SRPBCC)超家族,包含脂类转移结构域,参与脂类转运或代谢,与百脉根等中慢生根瘤菌相应基因的序列相似性达95%以上。这3个基因在共生条件下的表达水平都增高。分别构建了MCHK-5577、MCHK-2172和MCHK-2779基因突变菌株,与野生型菌株7653R相比,接种突变株MCHK-2172mut、MCHK-2779mut和MCHK-5577mut后的植株地上部分生物量和根瘤固氮酶活性显著降低。【结论】华癸中慢生根瘤菌脂质转移家族蛋白基因在共生互作过程中发挥重要作用,突变后明显影响共生固氮表型。本文的实验结果为深入研究脂类转移蛋白在共生固氮作用中的功能机制奠定了基础。     

猪眼角膜的生物力学特性

对猪眼角膜进行了有系统的单轴拉伸实验,通过实验来确定其极限强度,断裂能、显著非线性的应力-应变关系和滞后环.在不同的应变水平下进行了应为松弛实验并确定了连续松弛谱的各参数.从极限强度、断裂能和应力松弛来看,角膜的纵向和横向之间无重大的差异,据此,各向同性假定可用于初步的角膜力学模型.     

食用菌灭活原生质体电融合及属间融合产物的鉴定分析

食用菌因其显著的营养、保健、药用及综合利用价值受到世人青睐。原生质体融合技术则为食用菌的育种和遗传学研究提供了一条很好的途径。食用菌的种内、种间乃至属间、目间的原生质体融合均已有过报道,但这些工作大多利用营养缺陷型标记的亲株,采用化学融合法完成。这种融合的效率较低,对亲株的标记繁琐费时,甚至会对菌株性状产生不良影响。最近,一种具有较高融合效率的物理融合法——电融合法以及非遗传性标记法分别被一些研究者所采用。本研究将原生质体电融合法与灭活标记法相结合来获得食用菌的属间融合产物,并采用包括同工酶分析和RAPD(或AP-PCR)方法在内的分子生物学方法,对食用菌属间杂交后代的遗传学特性进行初步探讨。1 材料和方法