外源刀豆凝集素对菲律宾蛤仔免疫机能的影响

为了解外源刀豆凝集素对菲律宾蛤仔免疫因子的影响,开展了不同浓度刀豆凝集素对菲律宾蛤仔血细胞吞噬活性、溶菌酶(LSZ)、碱性磷酸酶(AKP)和超氧化物歧化酶(SOD)的影响研究。结果表明,投喂刀豆凝集素后第1、3、4、6、7天,菲律宾蛤仔吞噬细胞活性显著高于对照普通养殖(P0.05);投喂5μg/L刀豆凝集素后第4、6、7天,菲律宾蛤仔溶菌酶含量显著高于对照普通养殖(P0.05);投喂刀豆凝集素后第1～7天,菲律宾蛤仔碱性磷酸酶活性显著高于对照普通养殖(P0.05);投喂5μg/L刀豆凝集素后第3、7天,菲律宾蛤仔的超氧化物歧化酶活性显著高于对照普通养殖(P0.05)。刀豆凝集素在第2～5天对菲律宾蛤仔免疫力具有很大的促进作用,3μg/L刀豆凝集素效果最佳,第7天后投喂5μg/L刀豆凝集素效果最佳。     

贻贝凝集素抗-HIV活性研究

分离提取海洋无脊椎动物贻贝(Crenomytilus grayanus)凝集素,考察其抗HIV活性。采用半乳糖-Sepharose 6B亲和层析和Sephacryl S-200层析分离提取贻贝凝集素(Crenomytilus grayanus lectin,CGL),以光镜检查合胞体抑制试验,以ELSA测定HIVp24抗原表达水平。从海洋无脊椎动物贻贝中分离出的凝集素(CGL),为N-乙酰半乳糖胺/半乳糖(GalNAc/Gal)特异性的凝集素。CGL在27.88mg.L-1浓度时,对HIV诱导细胞病变的抑制达50%;在45.70mg.L-1时,对HIV-1复制的抑制达50%;同时在35.12mg.L-1浓度时,对HIV感染细胞融合的阻断达50%。     

抗虫转基因作物研究进展

简要介绍了转基因作物 (GMO)的发展概况 ,对近年来国内外抗虫 GMO在转 B.t.毒素蛋白GMO;转蛋白酶抑制剂 GMO;转植物凝集素 GMO;其他类型抗虫 GMO;抗虫的基因沉默与失活现象等 5个方面的研究进展进行了论述。最后 ,对抗虫 GMO的发展前景进行了展望。     

THE PATH OF CARBON IN PHOTOSYNTHESIS. XXXI. THE ROLE OF LECTINS

Radish (Raphanus sativus) and Swiss Chard (Beta vulgaris) seedlings, grown hydroponically, exhibited significantly greater increases in height and weight in medium containing α-mannoside supplemented with calcium and manganese salts, than in control treatments lacking one or more of those components. Furthermore, seeds sown on medium containing α-mannoside plus Ca²⁺and Mn²⁺showed accelerated germination. Calcium and manganese are necessary to maintain the protein conformation of mannose-binding lectins. In the presence of those cations, glycosides displace specific sugars bound to lectins, making them available to support plant growth.     

N-Acetyl-d-Glucosamine-Binding Lectin in Acropora tenuis Attracts Specific Symbiodiniaceae Cell Culture Strains

Many corals establish symbiosis with Symbiodiniaceae cells from surrounding environments, but very few Symbiodiniaceae cells exist in the water column. Given that the N-acetyl-d-glucosamine-binding lectin ActL attracts Symbiodiniaceae cells, we hypothesized that corals must attract Symbiodiniaceae cells using ActL to acquire them. Anti-ActL antibody inhibited acquisition of Symbiodiniaceae cells, and rearing seawater for juvenile Acropora tenuis contained ActL, suggesting that juvenile A. tenuis discharge ActL to attract these cells. Among eight Symbiodiniaceae cultured strains, ActL attracted NBRC102920 (Symbiodinium tridacnidorum) most strongly followed by CS-161 (Symbiodinium tridacnidorum), CCMP2556 (Durusdinium trenchii), and CCMP1633 (Breviolum sp.); however, it did not attract GTP-A6-Sy (Symbiodinium natans), CCMP421 (Effrenium voratum), FKM0207 (Fugacium sp.), and CS-156 (Fugacium sp.). Juvenile polyps of A. tenuis acquired limited Symbiodiniaceae cell strains, and the number of acquired Symbiodiniaceae cells in a polyp also differed from each other. The number of Symbiodiniaceae cells acquired by juvenile polyps of A. tenuis was correlated with the ActL chemotactic activity. Thus, ActL could be used to attract select Symbiodiniaceae cells and help Symbiodiniaceae cell acquisition in juvenile polyps of A. tenuis, facilitating establishment of symbiosis between A. tenuis and Symbiodiniaceae cells.     

Dioclea grandiflora andDioclea sclerocarpa seeds. A nutritional study

A nutritional study ofDioclea grandiflora (Mucuna) andDioclea sclerocarpa, two legume seeds related toCanavalia which grow extensively in South America and are used as a human food source, has been carried out. Whilst both seeds, when fed to rats at a level equivalent to 100g seed protein kg^–1 diet gave poor nutritional performance, the anti-nutritional factors involved were apparently different. WithDioclea grandiflora, the presence in the seed of a soluble small molecular weight component, which caused food intake to be reduced to levels well below that required to meet minimum protein, energy, vitamin and mineral requirements, led to poor growth. This factor could be reduced substantially by exhaustive dialysis or by aqueous ethanol extraction of the meal. These procedures may have potential practical applications. In addition, the constitutent lectin, which was partially resistant in vitro and in vivo to degradation by gastrointestinal enzymes, also contributed to growth depression. WithDioclea sclerocarpa, a non-haemagglutinating pH 7 soluble factor was primarily responsible for the poor performance of rats. This factor could not be removed by exhaustive dialysis. The apparently poor protein digestibility observed may be due to increased secretion of endogenous nitrogen.     

番茄凝集素荧光光谱学研究

用内源荧光测定和不带电荷的极性淬灭剂丙烯酰胺以及带电荷的I-离子、Cs+对番茄凝集素内源荧光进行淬灭研究,以揭示凝集素与小分子物质相互作用以及凝集素荧光生色基团的分布情况。结果表明,天然番茄凝集素在280nm和295nm激发时均显示λmax为332nm的荧光发射光谱,表明凝集素荧光生色基团位于相对疏水的环境中;中性淬灭剂丙烯酰胺对凝集素分子的荧光生色基团Trp残基的可接近程度为93.41%,而对阳离子淬灭剂Cs+离子的可接近程度为57.14%,阴离子淬灭剂不能淬灭凝集素的内源荧光,表明番茄凝集素荧光氨基酸残基约43%位于分子内部的疏水核心,57%位于分子近表面的疏水袋中,且氨基酸残基周围有大量的碱性氨基酸分布。     

海芋凝集素的纯化及其对4种昆虫细胞的毒杀作用

通过离体昆虫细胞培养研究海芋凝集素(Alocasia macrorrhiza lectin,AML)的毒杀作用。采用MTT法研究了提取自海芋叶0~30%、叶30%~80%、块茎0~30%、块茎30%~80%盐析段海芋凝集素粗品对4种昆虫细胞[草地贪夜蛾Spodoptera frugiperda Smith细胞(简称Sf-9细胞)、甜菜夜蛾Spodoptera exigua Hübner细胞(简称Se 301细胞)、粉纹夜蛾Trichoplusia ni Hübner细胞(简称Hi5细胞)和美洲棉铃虫Heliothis zea Boddie细胞(简称Hz细胞)]的毒杀作用,结果表明,海芋叶、块茎上述盐析段的粗提物均对4种昆虫细胞有明显的毒杀作用,其中以块茎30%~80%的样品毒杀活力最高:在2%浓度处理24 h条件下,上述4种细胞的相对死亡率分别为91.40%、91.62%、97.13%和82.30%。用Q Sepharose Fast Flow柱(2.6 cm×30 cm)对海芋块茎30%~80%的盐析物进行分离纯化,用最大活性峰样品对Sf-9细胞的毒杀作用进行研究,得到处理24 h的毒力回归方程,LC50为0.79%。     

基因枪导入法培育抗虫水稻

以含潮霉素抗性基因，GUS基因和雪花莲凝集素（GNA）基因的pWRG1515和pRSSGNA1为供体DNA，利用基因枪法转化上农香糯成熟胚诱导的愈伤组织，经抗性培养基筛选，从轰击的135块愈伤组织中得5株转 基因植株，GUS检测和PCR分析表明，外源基因已转入并整合到水稻基因组DNA上。     

海芋凝集素对几种鳞翅目昆虫的毒杀活性

采用饲喂、口腔灌注、腹足注射和喷雾等方法,比较了海芋凝集素粗品对3种鳞翅目昆虫菜粉蝶、亚洲玉米螟和斜纹夜蛾幼虫的毒杀活性.结果表明:海芋凝集素粗品对受试昆虫有一定的胃毒和触杀活性,其中海芋块茎凝集素粗品口腔灌注菜粉蝶幼虫的胃毒活性最高,5%海芋块茎凝集素粗品处理后5、6d,菜粉蝶幼虫的死亡率分别为62.5%和75.0%,表明海芋凝集素对昆虫的胃毒是其主要作用方式.