苏云金杆菌DNA芯片Oligo探针设计

迅速增长的分子生物学数据为总结新的生物学信息,进行生物研究尤其是分子生物学研究,提供了丰富的资料,利用苏云金杆菌的基因信息和一些生物学软件,设计特异性高、长度一致、熔解温度相近的Oligo探针,为后期打印成DNA芯片,进行苏云金杆菌鉴定打下基础。     

细小病毒B19诊断芯片的初步研究

初步探讨并制备细小病毒B19诊断芯片,进行实验室验证．用基因芯片点样仪将细小病毒B19诊断探针固定在特殊处理的玻片上,以细小病毒B19质粒重复检测．运用限制性显示(RD)技术,用Cy5标记的通用引物进行荧光标记,通过与基因芯片杂交,严谨洗涤,将非特异性的标记片段洗脱后,经扫描仪扫描,计算机解读．杂交结果显示,Cy5标记的探针均出现杂交信号,而阴性对照和空白对照的杂交信号均很弱：芯片检测具有高特异性、敏感性和可重复性．初步建立了较可靠的制备与检测细小病毒B19诊断芯片的方法,经验证诊断准确率高,假阳性率低．     

细小病毒B19感染实验室诊断技术的研究进展

人类细小病毒感染,临床可有多种表现,尤其可导致胎儿早产、流产、死胎、贫血、发育迟缓及形成积水型胎儿。本文拟从电镜检查、ＥＬＩＳＡ、固相放射免疫技术（ＲＩＡ）、分子杂交及多聚酶链反应（ＰＣＲ）等几个方面对该病毒感染实验室诊断的国外最新研究进展作一介绍。     

人细小病毒B19基因变异的研究进展

人细小病毒Ｂ１９简称Ｂ１９病毒,是细小病毒中惟一能感染人类的病毒,也是动物病毒中对人类具有致病性的最小单链线状ＤＮＡ病毒,其与儿童及成人的多种疾病密切相关。Ｂ１９病毒的基因变异对其致病、传播等具有重要影响,且与Ｂ１９病毒诊断试剂,疫苗的制备等关系密切。本文就Ｂ１９病毒基因组的变异状况,基因变异研究方法及研究Ｂ１９病毒基因变异的意义作一概述。     

人细小病毒B19与自然流产关系的研究

无菌留取 5 4例自然流产妇女和 43例妊娠无异常孕妇血清 ,用聚合酶链反应 (PolymeraseChainReaction ,PCR)检测的人细小病毒B19(HumanParvovirusB19,B19)DNA ,在自然流产组中人细小病毒B19DNA有 15例阳性 ,阳性率为 2 7.78%。正常对照组中 ,人细小病毒B19DNA有 2例为阳性 ,阳性率为 4.65 % ,用x2 检验 ,x2 =8.86,P <0 .0 1,两组有非常显著性差异。由此总结 ,人细小病毒B19感染可能是导致自然流产的原因之一     

人细小病毒B19病毒样颗粒的制备

采用昆虫杆状病毒表达系统,制备人细小病毒B19病毒样颗粒(VLPs)。先通过PCR方法合成细小病毒B19衣壳蛋白基因VP2,将其克隆到pFastBac1质粒,然后转化含杆状病毒穿梭载体Bacmid的E.coliDH10Bac感受态细胞,获得重组杆状病毒表达质粒Bacmid-VP2。在脂质体介导下转染Sf9昆虫细胞,包装重组杆状病毒rBac-VP2。利用rBac-VP2感染Sf9细胞表达B19VP2蛋白,通过间接免疫荧光、Western blotting等方法鉴定目的蛋白表达。采用两次超速离心的方法对表达产物进行纯化,纯化产物在透射电镜下可见直径约22nm的VLPs。本研究成功制备了人细小病毒B19的VLPs,为B19感染血清学检测方法的建立提供了参考。     

抗细小病毒B19-VP2单克隆抗体的建立

制备抗细小病毒B19－VP2单克隆抗体,用于检测人血清中的B19抗原,辅助诊断相关疾病;也可用于制备人类细小病毒基因工程疫苗。用纯化的基因工程表达的B19－VP2蛋白免疫BALB/c小鼠,取免疫小鼠的脾细胞和小鼠骨髓瘤Sp2/0细胞融合,有限稀释法克隆细胞。ELISA及IF证明抗体特异性。克隆筛选出4株细胞,并初步建立了检测B19－VP2抗原的双抗体夹心酶联免疫吸附试验,为双抗体夹心法检测B19抗原为临床相关疾病诊断提供了检测手段。     

In situ hybridization for the detection of human parvovirus B19 nucleic acid sequences in paraffin-embedded specimens

Parvovirus infection of pregnant women leading to a transplacentar infection of the fetus may result in hydrops fetalis, and ultimately in intrauterine death of the fetus. In situ hybridization with a biotinylated as well as with a³⁵S-labeled probe for human parvovirus B19 was performed on formalin-fixed paraffin-embedded (FFPE) tissue from a fetus suffering from non-immunologic hydrops fetalis. Histology was suggestive of viral infection probably with human parvovirus. Parvovirus DNA could be detected and precisely localized mainly in the nuclei of erythroid precursors cells within fetal blood vessels of all organs examined. There was no detection of B19 nucleic acid in parenchymal cells of the placenta or the fetal organs, nor within maternal blood cells. These findings are in agreement with the well-known properties of animal parvoviruses to replicate exclusively in proliferating cells. Taking into consideration the problems in diagnosing human parvovirus infection by light microscopy, we conclude that in situ hybridization with an appropriate non-radioactive probe is a valuable, rapid and safe complementary detection method for the diagnosis and study of human parvovirus infections. The³⁵S-labeled probe is more sensitive than the biotinylated probe, but has the disadvantages of lower resolution of the signal, longer duration of the assay, the hazard of radioactivity and the shorter shelflife of the probe.     

Clinical features and laboratory findings of human parvovirus B19 in human immunodeficiency virus-infected patients

Immunocompromised patients may develop severe chronic anaemia when infected by human parvovirus B19 (B19V). However, this is not the case in human immunodeficiency virus (HIV)-infected patients with good adherence to highly active antiretroviral treatment (HAART). In this study, we investigated the clinical evolution of five HIV-infected patients receiving HAART who had B19V infections confirmed by serum polymerase chain reaction. Four of the patients were infected with genotype 1a strains and the remaining patient was infected with a genotype 3b strain. Anaemia was detected in three of the patients, but all patients recovered without requiring immunoglobulin and/or blood transfusions. In all cases, the attending physicians did not suspect the B19V infections. There was no apparent relationship between the infecting genotype and the clinical course. In the HAART era, B19V infections in HIV-positive patients may be limited, subtle or unapparent.     

B19病毒11 kDa蛋白对Hela细胞内NF-KB信号通路的影响

11kDa蛋白作为B19病毒的一个非结构蛋白,可能在病毒复制周期中发挥重要作用.为了研究11 kDa蛋白对细胞内NF-κB信号通路的影响,首先通过原核表达纯化获得GST-11kDa融合蛋白,并制备免疫血清,利用免疫血清验证了11 kDa蛋白在Hela细胞呈胞浆定位.荧光素酶检测系统发现11 kDa蛋白能上调细胞内NF-κB转录活性,Western blotting进一步表明11 kDa蛋白能够引起细胞内IκB-α的降解.同时,11 kDa蛋白还能够上调细胞内炎性因子IL6启动子的活性,而该反应主要依赖于NF-κB通路.结果表明,11 kDa蛋白通过参与细胞内信号途径激活相关炎性因子的表达.     

等Tm检测探针寡核苷酸芯片在p53突变热点检测中的应用

用等长探针检测基因的点突变,不同GC含量探针的碱基错分辨率很难均一。尝试利用探针近似等Tm的原则设计、制备了检测抑癌基因p53外显子7中密码子245、248、249单碱基突变及缺失的寡核苷酸芯片。实验得到较好的碱基错配分辨率,检测不同位点的碱基错配分辨率较为一致,芯片检测结果与测序结果一致。实验结果为制备检测p53常见热点突变的寡核酸芯片奠定了基础。     

Enhanced kinetic extraction of parvovirus B19 structural proteins

Recombinant structural proteins (VP1 and VP2) of the human parvovirus B19 have been expressed simultaneously using the baculovirus expression system to form virus-like particles (VLPs) that have potential use as vaccines. In this study, we report optimization of extraction conditions to recover these VLPs from cell paste. Under hypotonic conditions with neutral pH these VLPs were poorly extracted (up to 3% extraction). Addition of reducing agents, detergents, salts, and sonication did not improve the extractability. While screening for conditions to improve the extractability of the VLPs, we discovered that a combination of higher pH and elevated processing temperature significantly increased the extraction. Whereas increasing pH alone increased extractability from 3% to 6% (pH increased from 8.0 to 9.5), the effect of elevated temperature was much more substantial. At 50 degrees C, we observed the extraction to be more than fivefold higher than that at room temperature (up to 25% extracted at pH 9.0). The kinetics of extraction at elevated temperatures showed a rapid initial rate of extraction (on the order of minutes) followed by a plateau. In addition, we compared the extraction of VP1 expressed alone. VP1 expressed alone is incapable of forming VLPs. We observed that non-VLP VP1 was easily extractable (up to 60% extracted) under conditions in which the VP1 + VP2 VLPs were not extractable. From these studies we conclude that parvovirus B19 structural proteins expressed to form VLPs have a hindered extractability as compared with non-VLP protein. This hindrance to extraction can be significantly reduced by processing at elevated temperatures and an increased pH, possibly due to the enhanced rates of solubilization and diffusion.     

人细小病毒B19分子生物学研究进展

人细小病毒B19 (Human parvovirus B19,简称B19病毒),是目前为止已知能够感染并引起人类疾病的两种细小病毒科成员之一。B19病毒作为一种重要病原,能够引起如儿童传染性红斑、急性再障危象、胎儿水肿甚至死胎等疾病。文中从B19病毒基因型、病毒受体、基因组结构特点与复制、病毒转录与转录后调控、病毒非结构和结构蛋白特点与功能以及病毒诊断及抗病毒药物研究策略6个方面来综述B19病毒的最新研究进展,以期为B19病毒致病机制的深入研究与治疗诊断策略的制定提供参考。     

Molecular and structural characterization of fluorescent human parvovirus B19 virus-like particles

Although sharing a T=1 icosahedral symmetry with other members of the Parvoviridae family, it has been suggested that the fivefold channel of the human parvovirus B19 VP2 capsids is closed at its outside end. To investigate the possibility of placing a relatively large protein moiety at this site of B19, fluorescent virus-like particles (fVLPs) of B19 were developed. The enhanced green fluorescent protein (EGFP) was inserted at the N-terminus of the structural protein VP2 and assembly of fVLPs from this fusion protein was obtained. Electron microscopy revealed that these fluorescent protein complexes were very similar in size when compared to wild-type B19 virus. Further, fluorescence correlation spectroscopy showed that an average of nine EGFP domains were associated with these virus-like structures. Atomic force microscopy and immunoprecipitation studies showed that EGFP was displayed on the surface of these fVLPs. Confocal imaging indicated that these chimeric complexes were targeted to late endosomes when expressed in insect cells. The fVLPs were able to efficiently enter cancer cells and traffic to the nucleus via the microtubulus network. Finally, immunoglobulins present in human parvovirus B19 acute and past-immunity serum samples were able to detect antigenic epitopes present in these fVLPs. In summary, we have developed fluorescent virus-like nanoparticles displaying a large heterologous entity that should be of help to elucidate the mechanisms of infection and pathogenesis of human parvovirus B19. In addition, these B19 nanoparticles serve as a model in the development of targetable vehicles designed for delivery of biomolecules.