基于西门利克森林病毒复制子的"自杀性"DNA疫苗载体的构建及其体外表达特性

对西门利克森林病毒(SFV)复制子质粒型表达载体pSfV1进行改造，即在SFV非结构蛋白(nSPs)上游插入依赖于RNA聚合酶Ⅱ的人巨细胞病毒立即早期启动子／增强子序列(hCMV IE Pro／Enh)，同时在pS-FV1的多克隆位点下游插入SV40 poly(A)终止信号序列，获得可以完全在DNA水平上操作并具有自主复制功能的表达载体pSFV-DNA。为了进一步探讨改造载体的转染效率、表达能力以及是否能诱导细胞凋亡等特性，将报告基因EGFP插入pSFV-DNA中亚基因组启动子下游，构建的重组表达质粒pSFV-EGFP转染BHK-21细胞，转染后12h即可观察到荧光，但转染效率明显低于直接由hCMV IE Pro／Enh驱动的EGFP真核表达质粒pEGFP-C1；提取转染后48h的细胞基因组DNA，电泳发现pSFV-EGFP转染细胞均呈典型的DNA断裂(ladder)，而pEGFP-C1转染细胞未观察到这种现象。上述结果表明：改造的载体不仅可完全在DNA水平上操作，而且能正确表达外源基因和诱导细胞凋亡，为开展各种病原微生物的“自杀性”DNA疫苗研究提供了良好的工具。     

"自杀性"DNA疫苗研究进展

DNA疫苗作为第三代全新的疫苗,具有传统疫苗和其他基因工程苗不可比拟的优点.但由于其安全性方面存在着一些尚待解决的问题,使得实际应用受到限制."自杀性"DNA疫苗是基于常规的DNA疫苗和自主复制型RNA疫苗而发展起来的一种新型疫苗.由于其制备原理和过程与常规DNA疫苗相类似,所以它具备常规DNA疫苗在制作、运输储存以及免疫等各方面的优点.同时由于它以甲病毒复制子为基础能诱导转染细胞自主凋亡,故比常规DNA疫苗更为安全有效.文章针对"自杀性"DNA疫苗载体的构建、作用机理、优点以及国内外研究情况作一介绍.     

Suicidal germination for parasitic weed control

Parasitic weeds of the genera Striga and Orobanche spp. cause severe yield losses in agriculture, especially in developing countries and the Mediterranean. Seeds of these weeds germinate by a chemical signal exuded by the roots of host plants. The radicle thus produced attaches to the root of the host plant, which can then supply nutrients to the parasite. There is an urgent need to control these weeds to ensure better agricultural production. The naturally occurring chemical signals are strigolactones (SLs), e.g. strigol and orobanchol. One option to control these weeds involves the use of SLs as suicidal germination agents, where germination takes place in the absence of a host. Owing to the lack of nutrients, the germinated seeds will die. The structure of natural SLs is too complex to allow multigram synthesis. Therefore, SL analogues are developed for this purpose. Examples are GR24 and Nijmegen‐1. In this paper, the SL analogues Nijmegen‐1 and Nijmegen‐1 Me were applied in the field as suicidal germination agents. Both SL analogues were formulated using an appropriate EC‐approved emulsifier (polyoxyethylene sorbitol hexaoleate) and applied to tobacco (Nicotiana tabacum L.) fields infested by Orobanche ramosa L. (hemp broomrape), following a strict protocol. Four out of 12 trials showed a reduction in broomrape of ≥95%, two trials were negative, two showed a moderate result, one was unclear and in three cases there was no Orobanche problem in the year of the trials. The trial plots were ca 2000 m²; half of that area was treated with stimulant emulsion, the other half was not treated. The optimal amount of stimulant was 6.25 g ha^?1. A preconditioning prior to the treatment was a prerequisite for a successful trial. In conclusion, the suicidal germination approach to reducing O. ramosa in tobacco fields using formulated SL analogues was successful. Two other options for weed control are discussed: deactivation of stimulants prior to action and biocontrol by Fusarium oxysporum. © 2016 Society of Chemical Industry     

"自杀性"DNA疫苗研究进展

核酸疫苗又称基因疫苗、DNA疫苗 ,是从基因治疗研究领域发展起来的一种全新的免疫防制剂。核酸疫苗具有许多优点 ,但是同时也有其不可避免的缺陷 ,这就使人们不得不把注意力集中在对传统的核酸疫苗进行改造以保持其优点 ,避免其缺陷上。“自杀性”DNA疫苗(suicidalDNAvaccine)就是基于常规DNA疫苗和“自主复制型”RNA疫苗 (self replicatingRNAvaccine)基础上发展起来的一种新型疫苗 ,不仅具有常规DNA疫苗易制备、运输、保存等方面的优点 ,而且还有“自主复制型”RNA疫苗的安全性与有效性 ,这使得其成为目前核酸疫苗研究的热点。文章就“自杀性”DNA疫苗的载体、构建、作用机理、优点以及研究现状作了综述     

猪水疱病自杀性DNA疫苗的初步研究

利用RT—PCR技术，用保真酶扩增获得猪水疱病病毒外壳蛋白1BCD基因，克隆于DNA复制子载体pSCAl中，获得重组质粒pSCA／1BCD。将重组质粒转染BHK-21细胞，RT-PCR法和间接免疫荧光法检测显示，猪水疱病病毒外壳蛋白基因在转染细胞中表达。豚鼠免疫试验表明，自杀性DNA疫苗pSCA／1BCD可诱导SVDV特异性抗体和T淋巴细胞增殖。     

青少年心理素质与自杀意念:一个有调节的中介模型

为探讨心理素质、领悟社会支持、负性生活事件与青少年自杀意念的关系及内在作用机制,建立了一个有调节作用的中介模型,并采用中学生心理素质量表、领悟社会支持量表、青少年生活事件量表和青少年自杀意念量表对全国2 035名中学生进行调查.结果显示:①青少年心理素质对自杀意念有显著的正向预测作用;②心理素质既可以直接影响青少年自杀意念,也可以通过领悟社会支持间接对自杀意念产生影响;③负性生活事件对该中介模型起到了调节作用,即负性生活事件较多时,心理素质和领悟社会支持对自杀意念的负向预测作用更强.认为领悟社会支持在心理素质与青少年自杀意念的关系中起部分中介作用,且该中介过程会受到负性生活事件的调节作用.