柞蚕核型多角体病毒(ApNPV)转移载体质粒pAp M2614的组建

自从美国科学家G.Smith等首次建立苜蓿尺蠖核型多角体病毒(AcNPV)转移载体表达系统以来,已被广泛用于外源基因的表达,成为世界上一新的具有巨大潜力的载体表达系统。为了进一步提高表达产量,降低成本,日本科学家前田进建立了家蚕核型多角体病毒(BmNPV)载体表达系统,并获得了高效表达。柞蚕是我国特产,以蛹滞育越冬,保存时间长,个体大,可工厂化生产。因此,组建柞蚕NPV转移载体,进而建立该载体表达系统,是目前利用昆虫活体为宿主进行外源基因表达较理想的昆虫杆状病毒载体表达系统。     

盐爪爪Na^＋/H^＋逆向转运蛋白和焦磷酸酶的亚细胞定位

将盐爪爪Na+/H+逆向转运蛋白基因(KfNHX1)和焦磷酸酶基因(KfVP1)分别构建至植物表达载体,利用基因枪介导的方法转化洋葱表皮细胞,通过荧光显微镜观察研究其亚细胞定位.结果表明,转化了KfNHX1(或KfVP1)-GFP融合蛋白的洋葱表皮细胞仅膜系统散发荧光,而对照组即未转入KfNHX1(或KfVP1)基因的细胞则整体均匀发出荧光.说明KfNHX1和KfVP1可能定位于细胞的膜系统,作为跨膜转运蛋白在离子的调控运输中发挥重要作用.     

增强DNA疫苗免疫应答的新进展

DNA疫苗为编码抗原蛋白的真核表达载体,注入体内后在原位表达所编码的抗原并诱导免疫应答,在预防感染、治疗自身免疫性疾病、过敏性疾病和肿瘤等疫病中有着很好的应用前景。但与灭活疫苗相比,其免疫效价还比较低。有多种策略能够增强或调节DNA疫苗诱导的免疫应答,其中,作为外源基因载体的质粒的组成及插入的有关基因均可直接或间接地影响免疫反应的效果,在构建DNA疫苗质粒时,加入细胞因子、融合信号、泛素等基因以及ISS序列,另外还可以通过设计一些对抗原提成细胞有影响的分子共注射,以及加入转移分子,都可以明显增强DNA疫苗的免疫效果,从而有利于研制更有效的DNA疫苗。     

Modulation of 2-Acetyl-1-pyrroline (2-AP) Accumulation,Yield Formation and Antioxidant Attributes in Fragrant Rice by Exogenous Methylglyoxal (MG) Application

Pot experiments were conducted to investigate the physiological and biochemical effect of exogenous MG application on two fragrant rice cultivars, Meixiangzhan and Yuxiangyouzhan. The MG application included four treatments: 1 mmol·L^–1 (MG1), 5 mmol·L^–1 (MG5), and 10 mmol·L^–1 (MG10), and deionized water as control (MG0). Results indicated that MG1 significantly increased the yield by 11.54–14.06% through promoting the seed-setting rate. Increases on grain 2-acetyl-1-pyrroline (2-AP) content at maturity were found in MG1. The contents of proline, Δ1-pyrrolin-5-carboxylic acid (P5C), pyrroline, and MG, and the activities of proline dehydrogenase (PDH), ornithine aminotransferase (OAT), and Δ1-pyrrolin-5-carboxylate synthase (P5CS) in plant tissues at all sampling stage were also increased in MG1 than MG0. In addition, although the malondialdehyde (MDA) content at all sampling stage was increased by MG application, MG1 increased the antioxidant enzyme activities and soluble protein content in all plant tissues and the pigment content in leaves. However, high-level MG (10 mmol·L^–1) application significantly decreased the yield and grain 2-AP content. Overall, this study suggested that exogenous MG application regulated the 2-AP accumulation, yield formation, and antioxidant attributes in fragrant rice, and that MG application at the concentration of 1 mmol·L^–1 increased the 2-AP content.

     

Phylogenetic and genetic characterization of a 2017 clinical isolate of H7N9 virus in Guangzhou,China during the fifth epidemic wave

Pathogenic H7N9 influenza viruses continue to pose a public health concern. The H7N9 virus has caused five outbreak waves of human infections in China since 2013. In the present study, a novel H7N9 strain (A/Guangdong/8H324/2017) was isolated from a female patient with severe respiratory illness during the fifth wave of the 2017 H7N9 epidemic. Phylogenetic analysis showed that the H7N9 viruses collected during the fifth wave belong to two different lineages: the Pearl River Delta lineage and the Yangtze River Delta lineage. The novel isolate is closely related to the Pearl River Delta H7N9 viruses, which were isolated from patients in Guangdong Province. The novel H7N9 isolate has an insertion of three basic amino acids in the cleavage site of hemagglutinin (HA), which may enhance virulence in poultry. The 2017 isolate also possesses an R292K substitution in the neuraminidase (NA) protein, which confers oseltamivir resistance. This study highlights the pandemic potential of the novel H7N9 virus in mammals; thus, future characterization and surveillance is warranted.     

Transmission-Blocking Antibodies against Mosquito C-Type Lectins for Dengue Prevention

C-type lectins are a family of proteins with carbohydrate-binding activity. Several C-type lectins in mammals or arthropods are employed as receptors or attachment factors to facilitate flavivirus invasion. We previously identified a C-type lectin in Aedes aegypti, designated as mosquito galactose specific C-type lectin-1 (mosGCTL-1), facilitating the attachment of West Nile virus (WNV) on the cell membrane. Here, we first identified that 9 A. aegypti mosGCTL genes were key susceptibility factors facilitating DENV-2 infection, of which mosGCTL-3 exhibited the most significant effect. We found that mosGCTL-3 was induced in mosquito tissues with DENV-2 infection, and that the protein interacted with DENV-2 surface envelop (E) protein and virions in vitro and in vivo. In addition, the other identified mosGCTLs interacted with the DENV-2 E protein, indicating that DENV may employ multiple mosGCTLs as ligands to promote the infection of vectors. The vectorial susceptibility factors that facilitate pathogen invasion may potentially be explored as a target to disrupt the acquisition of microbes from the vertebrate host. Indeed, membrane blood feeding of antisera against mosGCTLs dramatically reduced mosquito infective ratio. Hence, the immunization against mosGCTLs is a feasible approach for preventing dengue infection. Our study provides a future avenue for developing a transmission-blocking vaccine that interrupts the life cycle of dengue virus and reduces disease burden.