不同佐剂对含S+PreS1融合抗原的乙型肝炎病毒颗粒疫苗免疫原性的影响

本研究在前期工作基础上,用CHO细胞表达的含PreS1+S融合抗原的新型基因工程HBV颗粒疫苗(HBSS1)与Al(OH)3、CpG及CpG+Al(OH)3等佐剂配伍,在Balb/C小鼠模型上研究不同佐剂对HBV颗粒疫苗肌肉注射后免疫应答的影响,主要包括抗体滴度、抗体亚型分类及特异性细胞免疫(γ-IFNELISpot检测)。结果表明:CpG佐剂结合HBSS1颗粒疫苗可快速诱导(单针免疫)高水平的抗PreS1及S抗体,IgG2a/IgG1比率1,同时可诱导较高抗原特异的细胞免疫应答;Al(OH)3+CpG双佐剂组一次免疫后可诱导产生最高的抗S抗体滴度(1:105),其产生的抗体亚类包括IgG1、IgG2a与IgG2b;在S抗原N端(13~49aa)存在优势CTL表位。结论:CpG佐剂结合HBSS1颗粒疫苗应是发展新型治疗性乙肝疫苗的较佳选项。     

宏基因组文库中的组成型启动子在大肠杆菌中的克隆

启动子是决定基因表达水平的重要因素之一。组成型表达启动子被认为是工业上表达重要蛋白质的理想启动子。本研究利用蔗糖为唯一碳源的基本培养基对榨糖废水浸润的土壤微生物宏基因组文库进行筛选,获得两个阳性克隆。对其中一个克隆的柯斯质粒进行亚克隆,利用在线启动子预测和序列比对工具对其中一个亚克隆子进行分析,获得一个启动子序列。然后,利用PCR方法将该启动子和地衣芽孢杆菌的α-淀粉酶基因一起克隆到T载体上。结果表明该启动子在不加诱导剂的条件下能够在大肠杆菌中启动外源基因的高效表达。本研究结果为在生物领域中组成型启动子的应用研究提供了基础。     

HIV-1 glycoprotein 41 ectodomain induces activation of the CD74 protein-mediated extracellular signal-regulated kinase/mitogen-activated protein kinase pathway to enhance viral infection

Besides mediating the viral entry process, the human immunodeficiency virus (HIV-1) envelope protein gp41 can bind to many host cell components and regulate cell functions. Using a yeast two-hybrid system, we screened a human bone marrow cDNA library and identified a novel gp41-binding protein, CD74 (the MHC class II-associated invariant chain). Here, we report possible biological effects mediated by interaction between gp41 and CD74. We found that HIV-1 gp41 could bind directly to host CD74 in HIV-1-infected cells, and the peptide 6358 derived from gp41 loop region (aa 597-611) could effectively block the gp41-CD74 interaction. As a result of this binding, recombinant soluble gp41 and gp41 peptide 6358 activated the CD74-mediated ERK/MAPK pathway and significantly enhanced HIV-1 infection in vitro. Conversely, the enhancing effect could be suppressed by the recombinant CD74 extracellular domain. These results reveal a novel mechanism underlying gp41 mediation of HIV-1 infection and replication.     

精液源性病毒感染增强因子SEVI-HIV性传播中的重要因素

精液源性病毒增强因子(Semen-derived enhancer of viral infection,SEVI)是前列腺酸性磷酸酶(Prostatic acidphosphatase,PAP)位于PAP248-286的多肽片段,可增强人免疫缺陷病毒(Human immunodeficiency virus,HIV)的感染性。SEVI促进HIV感染的作用机制包括:①富含阳离子氨基酸残基的SEVI能通过静电作用降低HIV病毒颗粒与靶细胞之间的静电排斥;②SEVI在人体液中呈无序状态,利于病毒与靶细胞膜相互作用;③SEVI直接捕获HIV颗粒,提高病毒在靶细胞表面沉降速度,促进病毒与靶细胞的吸附和融合。目前已发现能抑制SEVI活性的物质包括:绿茶来源的EGCG(没食子儿茶素没食子酸酯)、氨基喹啉类小分子化合物Surfen、ThT类似物BTA-EG6等,能通过阻断HIV与SEVI结合或阻止其淀粉样纤维的形成,降低SEVI的病毒感染增强作用。研究SEVI的生物学特性及作用机制对防治HIV感染具有较为重要的指导意义。     

Molecular characterization and expression analysis of a KIFC1-like kinesin gene in the testis of Eumeces chinensis

The member of the kinesin-14 subfamily, KIFC1, is a carboxyl-terminal motor protein that plays an important role in the elongation of nucleus and acrosome biogenesis during the spermiogenesis of mammals. Here, we had cloned and sequenced the cDNA of a mammalian KIFC1 homologue (termed ec-KIFC1) from the total RNA of the testis of the reptile Eumeces chinensis. The full-length sequence was 2,339 bp that contained a 216 bp 5′-untranslated region (5′UTR), a 194 bp 3′-untranslated region (3′UTR) and a 1,929 bp open reading frame that encoded a special protein of 643 amino acids (aa). The calculated molecular weight of the putative ec-KIFC1 was 71 kDa and its estimated isoelectric point was 9.47. The putative ec-KIFC1 protein owns a tail domain from 1 to 116 aa, a stalk domain from 117 to 291 aa and a conserved carboxyl motor domain from 292 to 642 aa. Protein alignment demonstrated that ec-KIFC1 had 45.6, 42.8, 44.6, 36.9, 43.7, 46.4, 45.1, 55.6 and 49.8 % identity with its homologues in Mus musculus, Salmo salar, Danio rerio, Eriocheir sinensis, Rattus norvegicus, Homo sapiens, Bos taurus, Gallus gallus and Xenopus laevis, respectively. Tissue expression analysis showed the presence of ovary, heart, liver, intestine, oviduct, testis and muscle. The phylogenetic tree revealed that ec-KIFC1 was more closely related to vertebrate KIFC1 than to invertebrate KIFC1. In situ hybridization showed that the ec-KIFC1 mRNA was localized in the periphery of the nuclear membrane and the center of the nucleus in early spermatids. In mid spermatids, the ec-KIFC1 had abundant expression in the center of nucleus, and was expressed in the tail and the anterior part of spermatids. In the late spermatid, the nucleus gradually became elongated, and the ec-KIFC1 mRNA signal was still centralized in the nucleus. In mature spermatids, the signal of the ec-KIFC1 gradually became weak, and was mainly located at the tail of spermatids. Therefore, the ec-KIFC1 probably plays a critical role in the spermatogenesis of E. chinensis.     

印度块菌提取物抗氧化活性的研究

对印度块菌Tuber indicum子实体的提取物,包括55%乙醇粗提物(ECE)、石油醚提取物(PEF)和乙酸乙酯提取物(EAF)的清除DPPH自由基和羟基自由基能力、铁离子鳌合能力以及各提取物的总酚含量等进行了研究和测定,结果显示,3种提取物的清除自由基能力和铁离子鳌合能力具有显著差异(P0.05);ECE对DPPH自由基的清除活性最高,其EC50值为1.61g/L;EAF对羟基自由基及铁离子表现出较强的清除或螯合的能力,其EC50值分别为3.31g/L和0.70g/L;EAF的总酚含量(2.964mg GAE/g提取物)最高,其次是ECE,总酚含量为(2.618mg GAE/g提取物);PEF的清除自由基和铁离子鳌合能力较差,其总酚含量也最低(1.124mg GAE/g提取物);总酚含量与印度块菌提取物清除自由基以及鳌合铁离子的能力密切相关。     

An analysis of relationships among plant community phenology and seasonal metrics of Normalized Difference Vegetation Index in the northern part of the monsoon region of China

This study focuses on relationships between the phenological growing season of plant communities and the seasonal metrics of Normalized Difference Vegetation Index (NDVI) at sample stations and pixels overlying them, and explores the procedure for determining the growing season of terrestrial vegetation at the regional scale, using threshold NDVI values obtained by surface–satellite analysis at individual stations/pixels. The cumulative frequency of phenophases has been calculated for each plant community and each year in order to determine the growing season at the three sample stations from 1982 to 1993. The precise thresholds were arbitrarily set as the dates on which the phenological cumulative frequency reached 5% and 10% (for the beginning) and 90% and 95% (for the end). The beginning and end dates of the growing season were then applied each year as time thresholds, to determine the corresponding 10-day peak greenness values from NDVI curves for 8-km² pixels overlying the phenological stations. According to a trend analysis, a lengthening of the growing seasons and an increase of the integrated growing season NDVI have been detected in the central part of the research region. The correlation between the beginning dates of the growing season and the corresponding threshold NDVI values is very low, which indicates that the satellite-sensor-derived greenness is independent of the beginning time of the growing season of local plant communities. Other than in spring, the correlation between the end dates of the growing season and the corresponding threshold NDVI values is highly significant. The negative correlation shows that the earlier the growing season terminates, the larger the corresponding threshold NDVI value, and vice versa. In order to estimate the beginning and end dates of the growing season using the threshold NDVI values at sites without phenological data from 1982 to 1993, we calculated the spatial correlation coefficients between NDVI time-series at each sample station and other contiguous sites year by year. The results provide the spatial extrapolation area of the growing season for each sample station. Thus, we can use the threshold NDVI value obtained at one sample station/pixel for a year to determine the growing season at the extrapolation sites with a similar vegetation type for the same year. Received: 25 October 2000 / Revised: 19 June 2001 / Accepted: 19 June 2001     

组胺H_2受体激动剂和拮抗剂对WEHI_3细胞增殖的作用

近年来研究表明组胺及其受体在正常造血调控中起着重要作用。本研究用琼脂半固体培养技术观察了特异性组胺Ｈ２受体激动剂英普咪定和拮抗剂西咪替丁对髓系粒－单核细胞白血病干细胞株ＷＥＨＩ３细胞生长的影响。结果表明不同浓度的英普咪定（１０－８─１０－４ｍｏｌ／Ｌ）对集落数呈明显剂量依赖性抑制,与对照组比较ｐ＜０．０１。１０－１０─１０－９ｍｏｌ／Ｌ英普咪定对集落数无明显影响。１０－４─６×１０－４ｍｏｌ／Ｌ的英普咪定对集落产率的抑制作用趋于饱和。最大抑制效能为对照组的５４％（ｐ＜０．０１）。１０－４ｍｏｌ／Ｌ西咪替丁能完全阻断１０－８ｍｏｌ／Ｌ英普咪定的集落抑制作用。对≥１０－６ｍｏｌ／Ｌ英普咪定的作用西咪替丁均有部分阻断作用,与对照组比较Ｐ＜０．０１。单用西咪替丁对ＷＥＨＩ３细胞无明显直接作用。这提示ＷＥＨＩ３细胞株上存在有组胺Ｈ２受体,激动Ｈ２受体可抑制细胞增殖。