Host-attacking behavior of a eulophid parasite,Kratochviliana sp., to the leaf mining host,Phytomyza ranunculi (Diptera: Agromyzidae) during its stay on the leaf

The present paper studies how the female parasite of Kratochviliana sp. visits and attacks its host larvae of Ranunculus leaf mining fly, P. ranunculi at a single leaf visit. The parasite visited its hosts at random on the leaf. The frequency of host visits was independent of the host density and the proportion of hosts survived from the parasite attack, in a leaf and its distribution was expressed as a single straight line. It almost always attacked living hosts at the first host visit after isolated from them for one day but with the rate of about 0.5 at the subsequent visits. In consequence, the relationships of the number of host attacks and killed hosts to the host density drew satulated curves in each. A model of host attack by this parasite at its single leaf visit was formulated by modifyingBakker et al.'s model (1972) basing upon these observations and the attack avoidance by the parasite to already attacked hosts previously reported.     

Vegetation dynamics in Brittany heathlands after fire

The vegetation dynamics of heathlands in Brittany have been followed for three years in areas subject to fire in August 1976. The pre-fire vegetation had been analysed and mapped before its destruction. The structure of the community and the processes taking place in it (in terms of biomass, primary productivity, phenology, mineral nutrition and food value) had been examined. The redevelopment of the canopy was studied by the point-contact method along permanent line transects. This semi-quantitative study permits calculation of the relative frequency of each species and, from this, its cover. The growth form of each species and the stratification of the community are also indicated by this method. Permanent plots were also used to record changes in the vegetation, by means of a census of individuals and records of the development and growth strategy of each species. The plots were located in homogeneous areas, or on bare soil around seed parents in order to examine seed dispersal and seedling establishment. These two methods yielded detailed information on the nature of the secondary successions following fire in the heathlands of Brittany.

     

Differences in red cell shape of two inbred chicken lines

Summary Comparison of two inbred chicken lines (F_x > 99.9%) revealed significant differences in shape of the red blood cells (RBC). The length-width index was lower for both sexes in IC-line (1.46) when compared to CB-line chickens (1.88). Phenotypic expression of this character in F₁ hybrids and both backcross groups corresponded to the common manifestations of the metric parameters. The index in F₁ hybrid chickens deviated from intermediate values with the dominant tendency to oval RBC. An analysis of the segregating first backcross generation chickens did not show any association between RBC shape and the genotype in the blood group systems B, C, I, and D and the IgG allotypes. The differences in RBC shape were probably not associated with the survival of RBC in the blood circulation.     

水生态空间红线概念、划定方法及实证研究

我国面临着多方面、复杂的水生态问题:洪涝、干旱、水质污染、水生生境丧失以及人水关系日益疏远等等。解决这些问题,不能依赖单一目标的灰色工程方法,而必须从维护和保育水生态系统的完整性出发,来系统地解决问题。为此,如何定义一个相对完整的水生态系统的边界、划定维护其安全和健康的底线,即水生态空间红线,是用生态方法综合解决水问题的基础性的工作。研究提出了以保护水生态系统的综合生态服务为核心的水生态空间红线概念;提出了以水生态安全格局构建为基础的水生态空间红线划定方法和"水生态问题分析-水生态过程模拟和评价-水生态安全等级划分-水生态安全格局判定-水生态空间红线的划定"技术流程,分别划定水资源供给保护、水文调节保护、水生命支持和水文化保护四种类型的水生态保护空间红线,在此基础上,整合为综合的水生态空间红线,它呈现为对水生态过程具有关键意义的点、线、面和空间联系所构成的空间格局,并以雁栖湖流域为例进行了实证研究。     

截线抽样法在中国水域鲸豚考察中的应用及其局限性与改进建议

截线抽样法广泛应用于鲸豚类动物的考察。通过文献调查并结合我们自己的研究工作,本文从考察设计、
野外考察和数据分析三个方面分析了截线抽样法在我国水域应用时可能出现的问题。针对考察设计,提出了截
线设计的建议。针对野外考察,主要从观察平台、人员配置、观察方法和记录方法几个方面提出建议。针对分
析过程,介绍了使用R 编程平台和Distance 软件进行数据预处理和数据分析的简要过程。笔者期望本文的相关
建议有助于促进我国鲸豚类考察方法的规范化。     

吉林珲春自然保护区东北虎及其猎物资源调查

中国的野生东北虎(Panthera tigris altaica)数量已降到了极低的状态,及时开展有关东北虎及其猎物资源野外调查,对了解东北虎生存现状和制定保护策略都具有重大意义.吉林珲春东北虎国家级自然保护区是我国现存东北虎活动最频繁的地区之一,为了解该保护区的东北虎及其猎物资源状况,2009～2010年冬季,采用样...     

红鲫C1HD近交系RAPD标记的建立

目的建立红鲫C1HD近交系的RAPD标记。方法从80条随机引物中筛选出20条扩增效果和多态性较好的引物,对8尾红鲫C1HD近交系和8尾普通红鲫基因组DNA进行RAPD扩增。结果S333引物扩增出一条特异性条带,大小约为2.1 kb。结论S333引物扩增出的特异性条带可以作为区分普通红鲫与红鲫C1HD近交系的分子遗传标记。     

建立胃癌实验动物模型方法的研究

目的通过对人低分化胃癌细胞系SGC-7901状态和接种细胞数目的研究,建立良好的皮下接种胃癌的动物模型。方法采用腹腔注射SGC-7901细胞,使裸鼠形成腹水;光镜及电镜观察细胞状态;将购买的SGC-7901细胞以及形成腹水后的肿瘤细胞分别以1×108、1×107和1×106个进行裸鼠皮下接种,每组接种5只。观察其肿瘤形成时间、大小、状态及病理学变化。结果SGC-7901细胞接种裸鼠形成腹水后进行培养的肿瘤细胞增殖状态发生改变;购买的SGC-7901细胞以1×108及1×107接种裸鼠,在第21天肿瘤组织中央均出现出血和坏死;1×106的裸鼠第21天未见肉眼可见的肿瘤形成。腹水培养的肿瘤细胞,接种1×108的裸鼠在第21天肿瘤组织中央可见大面积的出血和坏死;接种1×107及1×106的裸鼠在第21天均未见出血和坏死,接种1×107的肿瘤组织体积较大。结论SGC-7901细胞接种裸鼠形成腹水后的细胞,更容易建立SGC-7901细胞皮下接种的胃癌动物模型,其中以接种细胞数为1×107的肿瘤生长较好,更适用于胃癌的实验研究。     

索拉菲尼联合阿霉素对人肝癌细胞株HepG2的抑制作用

目的：探讨索拉非尼（Sorafenib）和阿霉素（adriamycin）联合用药对肝癌细胞株nepG2的作用及可能的机制。方法：以不同浓度索拉非尼和不同浓度阿霉素分别组成单药组和索拉非尼＋阿霉素联合用药组作用于HepG2细胞,MTT法检测增殖抑制率、流式细胞仪分析细胞周期和凋亡率。结果：索拉非尼、阿霉素单药与联用均能抑制HepG2细胞增殖,呈剂量依赖效应,两药联用有协同效应（P〈0.01）。索拉非尼、阿霉素单药与联用均能诱导HepG2细胞凋亡,并以联合组更为明显,与对照组比较有显著的统计学意义（P〈0.01）。索拉非尼及阿霉素单药作用均可使细胞周期阻滞于G0-G1期,联合用药组G0/Gl期细胞比率低于索拉非尼及阿霉素单药组,S期细胞比率高于单药组;阿霉素能抑制HepG2细胞Survivin mRNA表达诱导细胞的凋亡。结论：索拉非尼与阿霉素联合作用于人肝癌HepG2细胞具有协同作用,其机制可能是通过多途径共同抑制HepG2细胞增殖及诱导细胞凋亡。     

中国生态环境过渡的一个重要地带

本文揭示沿腾冲－黑河联线的地带不仅如胡焕庸早年提出是一条人口地理界线,而且是一条生态环境界线,更重要的是,腾冲－黑河线表征的方向,在历史时期表现为全球变化的特征方向。