白花草木樨地蜘蛛群落结构及多样性

白花草木樨地蜘蛛有11科31属41种,随着时间的变化,优势种依次为印痕球蛛(Therionimpressum)、灌木新园蛛(Neoscona adianta)、条纹花蟹蛛(Xysticus striatipes)和星豹蛛(Pardosa astrigera),蜘蛛的生物学特性、植被情况、食物供应和人为活动对蜘蛛群落结构和优势种群消长变化有不同程度的影响,分析的结果可为草地害虫的综合防治提供参考.     

CSTX-9, a toxic peptide from the spider Cupiennius salei: amino acid sequence, disulphide bridge pattern and comparison with other spider toxins containing the cystine knot structure

CSTX-9 (68 residues, 7530.9 Da) is one of the most abundant toxic polypeptides in the venom of the wandering spider Cupiennius salei. The amino acid sequence was determined by Edman degradation using reduced and alkylated CSTX-9 and peptides generated by cleavages with endoproteinase Asp-N and trypsin, respectively. Sequence comparison with CSTX-1, the most abundant and the most toxic polypeptide in the crude spider venom, revealed a high degree of similarity (53% identity). By means of limited proteolysis with immobilised trypsin and RP-HPLC, the cystine-containing peptides of CSTX-9 were isolated and the disulphide bridges were assigned by amino acid analysis, Edman degradation and nanospray tandem mass spectrometry. The four disulphide bonds present in CSTX-9 are arranged in the following pattern: 1-4, 2-5, 3-8 and 6-7 (Cys₆-Cys₂₁, Cys₁₃-Cys₃₀, Cys₂₀-Cys₄₈, Cys₃₂-Cys₄₆). Sequence comparison of CSTX-1 with CSTX-9 clearly indicates the same disulphide bridge pattern, which is also found in other spider polypeptide toxins, e.g. agatoxins (ω-AGA-IVA, ω-AGA-IVB, μ-AGA-I and μ-AGA-VI) from Agelenopsis aperta, SNX-325 from Segestria florentina and curtatoxins (CT-I, CT-II and CT-III) from Hololena curta. CSTX-1/CSTX-9 belong to the family of ion channel toxins containing the inhibitor cystine knot structural motif. CSTX-9, lacking the lysine-rich C-terminal tail of CSTX-1, exhibits a ninefold lower toxicity to Drosophila melanogaster than CSTX-1. This is in accordance with previous observations of CSTX-2a and CSTX-2b, two truncated forms of CSTX-1 which, like CSTX-9, also lack the C-terminal lysine-rich tail. Received 23 July 2001; accepted 31 July 2001     

蜘蛛丝应力—应变行为的分子结构机理

利用激光拉曼光谱技术研究了大腹园蛛牵引丝、蛛网框丝和内层包卵丝的分子构象,分析了蜘蛛丝的分子构象差异对其应力-应变行为的影响,探索了蜘蛛丝优异力学性能的分子结构机理。     

尘螨肠道微生物蛋白核苷二磷酸激酶的克隆、表达及纯化

根据 GenBank 中 NDP kinase 的基因序列,采用生物信息学方法将其中稀有密码子改造为大肠埃希菌常用密码子并进行二级结构优化,合成 NDP kinase 基因,构建原核表达载体 pET28a-NDP kinase 并酶切鉴定其序列,在大肠埃希菌 BL21（DE3）中用异丙基-β-D-硫代半乳糖苷（IPTG）诱导表达,重组产物采用镍离子金属螯合亲和层析柱纯化.经密码子改造和二级结构优化后 NDP kinase 基因长度为490 bp,其编码蛋白理论分子量为21.5 kDa,重组表达载体经酶切鉴定与理论推测结果相符,在大肠埃希菌 BL21（DE3）中该基因经 IPTG 诱导可高效表达,纯化后的重组蛋白分子量约为21.5 kDa,其单一蛋白纯度达95;以上.本研究成功构建了尘螨肠道微生物蛋白核苷二磷酸酶（NDP kinase）基因的 pET28a 原核重组质粒,为进一步研究 NDP kinase 在尘螨疫苗免疫治疗中的作用机理提供了基础.     

个性化搜索引擎算法研究

搜索引擎是用户利用网络资源不可或缺的工具,但目前搜索引擎的查准率有待提高。对于不同的用户而言,即便是相同的查询词其期望的查询对象可能不同,那么搜索引擎此时的查准率其实就是让搜索引擎具有个性化搜索的特点。个性化搜索引擎的关键是用户兴趣的确定和文档兴趣值的确定,只有把抽象的个性化兴趣量化成数值类的模型,才可以了解用户真正的需求和量化文档与兴趣的相关程度,从而准确地对网页进行筛选并达到个性化排序的功能。     

小五台山典型生境的蜘蛛群落结构

2006年7月对小五台山国家级自然保护区的滩涂、草丛、灌木丛等典型生境的蜘蛛群落结构进行调查,采用样方采集与随机扫网相结合的方法,共采得蜘蛛标本263头,隶属于16科43属55种(属).运用群落多样性指数进行分析,结果表明:滩涂中蜘蛛优势类群较明显,个体密度、物种丰富度和多样性较低:灌木丛和草丛中的蜘蛛优势类群不明显,个体密度、物种丰富度和多样性相对较高.小五台山地区蜘蛛群落结构的现状是种类丰富,优势种不明显,个体数量较少.     

朱砂叶螨危害初期豇豆幼苗叶片PPO、PAL及POD的研究

对朱砂叶螨(Tetranychus cinnabarinus(Boisduval))危害后豇豆(Vigna sinensis)幼苗叶片PPO、PAL和POD活性及同工酶进行了研究。结果显示：随着危害时间延长，处理叶片PPO、PAL和POD的活性与对照相比均升高，差异显著，且两处理之间也存在显著差异；POD同工酶电泳结果显示，随着危害程度的增大，除了部分同工酶谱带加强外，还诱导产生了新的同工酶谱带。     

蛛形图的全图和中心图的均匀染色

通过研究蛛形图的全图和中心图的性质,给出具体的独立集分法,得到了蛛形图G删去头点后有n条长为n-1的路.把图G的全图记为T(G),则G的全图的均匀色数χ{Eq}[T(G)]=n+1.把 G 的中心图记为{C(G)},也得到了这样的蛛形图G的中心图的均匀色数:当 n=2k时,χ{Eq}[C(G)]=2k2+1;当n=2k+1时,{χ{Eq}[C(G)]=}2k2+3k+1.     

福建茶园前气门亚目和内气门亚目益螨资源初步分类研究

针对我国茶树害螨为害严重、益螨研究薄弱的现状,笔者对福建部分地区茶园的益螨资源进行了调查,并对已采获的茶园益螨标本约20000余号,制作玻片标本2000余号,经过对其科的初步分类鉴定,已鉴定出前气门亚目和内气门亚目捕食性或寄生性益螨9总科、13科,分别是:吸螨科Bdellidae、巨须螨科Cunaxidae、长须螨科Stigmaeidae、小真古螨科Eupalosellidae、肉食螨科Cheyletidae、大赤螨科Anystidae、赤螨科Erythraeidae、绒螨科Trombidiidae、真足螨科Eupodidae、莓螨科Rhagidiidae、镰螯螨科Tydeidae、镰寄螨科Iolinidae、阿里螨科Alycidae.阿里螨科Alycidae为中国新记录科.另外,还有大量前气门亚目以外的螨类标本,尚待进一步研究鉴定.     

Does nutritional status constrain adoption of more costly and less risky foraging behaviour in an Amazonian shelter-building spider?

Individual nutritional status may increase marginal foraging costs and potentially drive animal foraging strategies. Here, we investigated how it might affect foraging strategies of the shelter-building spider Hingstepeira folisecens (Hingston 1932) (Araneidae). This spider can catch prey using two strategies with different relative costs: ‘pulling’ (higher energy expenditure) and ‘pursuing’ (lower energy expenditure). We conducted experiments by offering prey at a fixed distance from the shelter entrance to investigate if spiders with lower nutritional status would exhibit riskier but less costly foraging behaviours more frequently than spiders with better status. The nutritional status did not affect the foraging behaviours adopted by H. folisecens. Additionally, the frequency of both foraging behaviours was similar. Therefore, our results did not provide any evidence that individual nutritional status is a factor driving the selection of foraging behaviours in H. folisecens. We suggest that the malnourished spiders should adopt additional strategies to compensate for the costs of pulling behaviour, especially when prey is far from the shelter. Furthermore, it is possible that other factors, like relative prey size in relation to web size, can help us to understand the threshold that determines when such individuals must adopt one of two possible behaviours.