Bioinformatic analysis of BBTV satellite DNA in Hainan

Banana bunchy top virus (BBTV),family Nanaviridae,genus Babuvirus,is a single stranded DNA virus (ssDNA) that causes banana bunchy top disease (BBTD) in banana plants.It is the most common and most destructive of all viruses in these plants and is widespread throughout the Asia-Pacific region.In this study we isolated,cloned and sequenced a BBTV sample from Hainan Island,China.The results from sequencing and bioinformatics analysis indicate this isolate represents a satellite DNA component with 12 DNA sequences motifs.We also predicted the physical and chemical properties,structure,signal peptide,phosphorylation,secondary structure,tertiary structure and functional domains of its encoding protein,and compare them with the corresponding quantities in the replication initiation protein of BBTV DNA1.     

脉冲电场对真皮成纤维细胞生长和膜流动性的影响

采用MTT比色分析法检测脉冲电场(f=50Hz,t=20μs,Epp=1V/m),对真皮成纤维细胞增殖的影响,结果表明,电场作用1分钟和5分钟,均产生促进细胞增殖的效果(P<0.05和P<0.001),而较长时间(t≥10分钟)的电场作用则显著抑制细胞的正常增殖(P<0.001)。 采用荧光偏振法研究了脉冲电场对真皮成纤维细胞膜流动性的影响。结果表明,电场作用5分钟后即刻引起膜流动性的显著增加。而电场作用45分钟后,需经过一段时间的温育(30 分钟),才表现出膜流动性的降低。说明不同作用时间的电场可以造成膜流动性的增加或降低,而且对膜流动性的影响是可逆的。我们认为,脉冲电场所引起的膜流动性改变是细胞分裂能力发生变化的原因之一。     

地上部植食者褐飞虱对不同水稻品种土壤线虫群落的影响

地上和地下部生物群落的交互作用对于调控陆地生态过程具有重要作用。在盆栽条件下利用2×2析因设计研究了褐飞虱(Nilaparvata lugens)取食不同水稻品种后对土壤线虫群落的影响。结果表明, 褐飞虱侵害水稻9 d后, 感虫品种(广四和汕优63)的土壤线虫总数、属数及自生线虫(食细菌线虫、食真菌线虫和捕食性线虫)数量增加, 并且一般达到显著水平(P<0.05); 而上述指标在抗虫品种(汕优559和IR36)土壤中则呈现相反的趋势。植食性线虫数量在强感虫品种广四上显著增加(P<0.05), 而在强抗虫品种IR36上显著减少(P<0.05)。褐飞虱和水稻品种对土壤线虫的生态指数(线虫通道指数、Shannon-Wiener指数、成熟度指数、富集指数和结构指数)没有明显影响, 可能与供试土壤线虫群落组成单一及褐飞虱作用时间较短有关。总之, 褐飞虱强烈影响土壤线虫数量、群落组成和营养结构, 并且作用的方向(促进或抑制)和程度依赖于水稻的品种特性, 揭示出地上部植食者的短期侵害将对稻田土壤生态系统的结构和功能产生深远影响。     

Human umbilical cord-derived MSC culture: the replacement of animal sera with human cord blood plasma

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) hold great potential for their therapeutic use in various clinical diseases. Many publications have reported on human blood-derived alternatives to animal serum for culturing mesenchymal stem cells, such as human serum, allogenic umbilical cord blood serum, and human platelet derivatives. However, it is not clear whether human umbilical cord blood plasma (UCBP), as the surplusage of umbilical cord blood mesenchymal stem cell extraction, could be used. In this study, in order to make the best of umbilical cord blood, the human UCBP was dialyzed to replace fetal bovine serum (FBS) in the culture medium. hUC-MSCs were cultured in the new medium. Cell growth rate, specific biomarkers, and differentiation properties were detected to characterize the cell proliferation and MSC-specific properties. The hUC-MSCs cultured in such derived medium were verified with proliferation rate, cluster differentiation markers, cell cycle, as well as differentiation capabilities. Such dialyzed human UCBP is fully comparable with, if not superior to, FBS in deriving and culturing hUC-MSCs.     

NOX4-Derived Reactive Oxygen Species Drive Apelin-13-Induced Vascular Smooth Muscle Cell Proliferation via the ERK Pathway

Apelin is the endogenous ligand of the G-protein-coupled receptor, apelin–angiotensin receptor-like 1 (APJ). Vascular smooth muscle cells express both apelin and APJ, which are important regulatory factors in the cardiovascular system. Apelin-13 significantly stimulated vascular smooth muscle cell proliferation. However, little is known about the precise cellular mechanisms responsible for vascular smooth muscle cell proliferation induced by apelin-13. Here, we present novel data that indicate the key role of NADPH oxidase 4-derived reactive oxygen species in proliferation of vascular smooth muscle cells treated with apelin-13. Apelin-13 stimulated reactive oxygen species production in a concentration- and time-dependent manner. Furthermore, DPI impaired apelin-13-induced reactive oxygen species generation and vascular smooth muscle cell proliferation. Apelin-13-treatment increased the expression of NADPH oxidase 4 in a dose-dependent manner. Down-regulation of NADPH oxidase 4 using siRNA prevented apelin-13-induced reactive oxygen species generation and vascular smooth muscle cell proliferation. An increase in reactive molecules can trigger the activation of ERK stress-sensitive signaling pathways. Additionally, siRNA-NOX4 and DPI reversed the phosphorylation of ERK induced by apelin-13. Apelin-13 induced vascular smooth muscle cell proliferation by NOX4-derived ROS via the ERK signaling pathway.     

Construction of a recombinant BHV-1 expressing the VP1 gene of foot and mouth disease virus and its immunogenicity in a rabbit model

Foot-and-mouth disease (FMD) and infectious bovine rhinotracheitis (IBR) are two important infectious diseases of cattle. Using bovine herpesvirus type 1 (BHV-1) as a gene delivery vector for development of live-viral vaccines has gained widespread interest. In this study, a recombinant BHV-1 was constructed by inserting the synthetic FMDV (O/China/99) VP1 gene in the the gE locus of BHV-1 genome under the control of immediately early gene promoter of human cytomegalovirus (phIE CMV) and bovine growth hormone polyadenylation (BGH polyA) signal. After homologous recombination and plaque purification, a recombinant virus named BHV-1/gE⁻/VP1 was acquired and identified. The immunogenicity was confirmed in a rabbit model by virus neutralization test and enzyme-linked immunosorbent assay (ELISA). The result indicated that the BHV-1/gE⁻/VP1 has the potential for being developed as a bivalent vaccine for FMD and IBR.     

脓肿分枝杆菌经Toll样受体2介导的JNK/ERK信号通路诱导巨噬细胞表达肿瘤坏死因子α和白细胞介素8

为探讨脓肿分枝杆菌脓肿亚种和马赛亚种经Toll样受体2(Toll-like receptor 2,TLR2)介导的c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)和细胞外信号调节激酶(extracellular signal-regulated kinase,ERK)诱导THP-1巨噬细胞内肿瘤坏死因子α(tumor necrosis factor α,TNF-α)和白细胞介素8(interleukin 8,IL-8)表达的相关分子机制,本研究将脓肿分枝杆菌脓肿亚种和马赛亚种感染THP-1巨噬细胞,细菌与巨噬细胞最佳感染之比为感染复数(multiplicity of infection,MOI)＝3,用荧光定量聚合酶链反应(polymerase chain reaction,PCR)检测THP-1巨噬细胞感染两细菌亚种6 h后的胞内TNF-α和IL-8 mRNA水平,以及分别阻断TLR2、JNK 和ERK信号蛋白后TNF-α和IL-8 mRNA水平的变化。结果显示,脓肿分枝杆菌脓肿亚种和马赛亚种作用于THP-1巨噬细胞6 h后,均可诱导细胞内TNF-α和IL-8 mRNA水平显著上调,差异有统计学意义(P＜0.05);分别阻断TLR2、JNK和ERK信号蛋白,脓肿亚种感染THP-1巨噬细胞后胞内TNF-α和IL-8 mRNA上调水平出现明显抑制,差异有统计学意义(P＜0.05);分别阻断TLR2和JNK信号蛋白,马赛亚种感染THP-1巨噬细胞后胞内TNF-α和IL-8 mRNA上调水平均出现明显抑制,差异有统计学意义(P＜0.05);而阻断ERK信号蛋白后,马赛亚种组仅见IL-8 mRNA水平明显抑制,差异有统计学意义(P＜0.05),而TNF-α mRNA水平未见明显变化,差异无统计学意义(P＞0.05)。本研究提示,脓肿分枝杆菌脓肿亚种和马赛亚种均可作用于TLR2,诱导THP-1细胞内TNF-α和IL-8 mRNA水平上调,脓肿亚种可经JNK和ERK信号蛋白诱导TNF-α mRNA上调,马赛亚种可经JNK信号蛋白诱导TNF-α mRNA上调;脓肿亚种和马赛亚种诱导IL-8 mRNA上调可能与JNK和ERK信号蛋白相关。     

黄霉素产生菌BBG1213的发酵工艺优化

对黄霉素产生菌Streptomyces bambergiensis1213培养基配方、种子培养时间及摇瓶装液量等培养条件进行优化,结果表明:当发酵培养基配方为:玉米淀粉3.5%、玉米浆0.6%、酵母粉1.0%、蛋白胨0.3%、黄豆饼粉2.5%、(NH4)2SO40.13%、K2HPO40.03%,BBG1213产抗水平最高;种子培养时间36h为宜;摇瓶装液量30ml,发酵周期86h-89h最佳。采用双碟法,建立了发酵液中黄霉素含量测定方法。     

氰戊菊酯在茶叶和茶汤中的残留动态及最大残留限量评价

在生长均匀的茶园喷施氰戊菊酯(fenvalerate),采摘施药后2 h和1 h、2 h、3 h、5 h、7 h、9 h、14 h、21天的茶树鲜叶加工成绿茶,用气相色谱法测定成茶、茶汤和茶渣中反式氰戊菊酯和顺式氰戊菊酯的含量,研究了氰戊菊酯在成茶、茶汤中的残留动态。结果表明:反式氰戊菊酯和顺式氰戊菊酯在成茶中的残留水平随施药间隔天数的增加呈下降趋势,20 mL/667 m2施药剂量下,分别由施药当天2 h的9.40 mg/kg和17.51 mg/kg减小到第21天的1.07 mg/kg和1.53 mg/kg,消解幅度为88.62%和91.26%,40 mL/667 m2施药剂量下,分别由施药当天2 h的20.37 mg/kg和38.67 mg/kg减小到第21天的1.94 mg/kg和3.06 mg/kg,消解幅度为90.49%和92.09%。茶汤中氰戊菊酯含量(y)与成茶中氰戊菊酯含量(x)呈二项式函数关系,反式氰戊菊酯的函数关系为y=-0.0007x2 0.0242x,顺式氰戊菊酯的函数关系为y=-0.0002x2 0.0114x。按我国标准饮茶摄入的氰戊菊酯占每日允许摄入量的0.049%,足以达到保护人体健康水平的要求。而按欧盟的标准,饮茶摄入的氰戊菊酯占每日允许摄入量的0.0019%,即在10-5水平上,这样的风险水平已接近对非阈效应化学物质的风险控制水平(10-6)。