小蔗螟Cytb基因序列的分析研究(鳞翅目:螟蛾总科:草螟亚科)

扩增并测定了小蔗螟线粒体细胞色素b(Cyt b)基因,其序列全长1146 bp,利用分子生物学软件分析了包括小蔗螟在内的4目(鳞翅目、双翅目、鞘翅目、缨尾目)共19条Cyt b基因序列.分析结果显示:鳞翅目昆虫AT含量明显低于其它昆虫,其中小蔗螟AT含量为75.1%;AT含量与A或T碱基使用的偏倚没有明显的相关性;碱基替换主要发生在密码子第三位,并且颠换率远大于转换率;密码子使用频率与基因碱基组成AT偏倚有相关性;相比于核苷酸数据,氨基酸所显示的遗传距离更为准确;使用Cyt b基因构建的系统进化树支持昆虫的单源进化学说.     

Microbial Transport, Survival, and Succession in a Sequence of Buried Sediments

Abstract Two chronosequences of unsaturated, buried loess sediments, ranging in age from <10,000 years to >1 million years, were investigated to reconstruct patterns of microbial ecological succession that have occurred since sediment burial. The relative importance of microbial transport and survival to succession was inferred from sediment ages, porewater ages, patterns of abundance (measured by direct counts, counts of culturable cells, and total phospholipid fatty acids), activities (measured by radiotracer and enzyme assays), and community composition (measured by phospholipid fatty acid patterns and Biolog substrate usage). Core samples were collected at two sites 40 km apart in the Palouse region of eastern Washington State, near the towns of Washtucna and Winona. The Washtucna site was flooded multiple times during the Pleistocene by glacial outburst floods; the Winona site elevation is above flood stage. Sediments at the Washtucna site were collected from near surface to 14.9 m depth, where the sediment age was approximately 250 ka and the porewater age was 3700 years; sample intervals at the Winona site ranged from near surface to 38 m (sediment age: approximately 1 Ma; porewater age: 1200 years). Microbial abundance and activities declined with depth at both sites; however, even the deepest, oldest sediments showed evidence of viable microorganisms. Same-age sediments had equal quantities of microorganisms, but different community types. Differences in community makeup between the two sites can be attributed to differences in groundwater recharge and paleoflooding. Estimates of the microbial community age can be constrained by porewater and sediment ages. In the shallower sediments (<9 m at Washtucna, <12 m at Winona), the microbial communities are likely similar in age to the groundwater; thus, microbial succession has been influenced by recent transport of microorganisms from the surface. In the deeper sediments, the populations may be considerably older than the porewater ages, since microbial transport is severely restricted in unsaturated sediments. This is particularly true at the Winona site, which was never flooded.     

Sulfation of fucoidin in focus embryos: III. Required for localization in the rhizoid wall

Zygotes of the brown alga Fucus distichus L. Powell accumulate a sulfated polysaccharide (fucoidin) in the cell wall at the site of rhizoid formation. Previous work indicated that zygotes grown in seawater minus sulfate do not sulfate the preformed fucan (an unsulfated fucoidin) but form rhizoids. Under these conditions, we determined whether sulfation of the fucan is required for its localization in the rhizoid wall. This was accomplished by developing a specific stain for both the fucan and fucoidin. Using a precipitin assay, we demonstrated in vitro that the lectin ricin (RCA(I)) specifically complexes with both the sulfated and desulfated polysaccharide. No precipitate is observed when either is incubated in 0.1 M D-galactose or when RCA(I) is mixed with laminarin or alginic acid, the other major polysaccharides in Fucus. RCA(I) conjugated with fluorescein isothiocyanate (FITC) is also shown to bind specifically to fucoidin using a filter paper (DE81) assay. When added to zygotes, RCA(I)-FITC binds only to the site of fucoidin localization, i.e., the rhizoid cell wall. However, RCA(I)-FITC is not observed in the rhizoid wall of zygotes grown in the absence of sulfate. This observation is not due to inability of RCA(I)-FITC to bind to the fucan in vivo. Chemically desulfated cell walls that contained fucoidin in the rhizoid wall bind RCA(I)-FITC only in the rhizoid region. Also, the concentration of fucose-containing polymers and polysaccharides that form precipitates with RCA(I) is the same in embryos grown in the presence or absence of sulfate. If sulfate is added back to cultures of zygotes grown without sulfate, fucoidin is detected at the rhizoid tip by RCA(I)-FITC several hours later. These results support the conclusion that the enzymatic sulfation of the fucan is a modification of the polysaccharide required for its localization and/or assembly into a specific region of the cell wall.     

A rapid technique to predict malting quality in barley prior to harvest

Samples of grain from three spring barley cultivars of differing malting quality were collected at regular intervals during four weeks prior to harvest. The samples were dried, then assessed for relative grain hardness using the "Milling Energy" test. Ranking order of the cultivars for this character, which relates strongly to malting quality, was unaltered throughout. In a further experiment, it was demonstrated that selection for milling energy could be successfully practised on oven-dried grain collected six weeks after ear emergence.     

四川老君山自然保护区不同生境鸟类多样性研究

2006年4~5月采用"点样带法"(point transects)对四川老君山自然保护区的鸟类物种组成和种群数量进行了调查,共记录到85种鸟类,分属7目22科。其中,国家级保护鸟类5种,我国特有种13种,优势种4种。把调查区域划分为3种生境:原始林、次生林和人工林,并对各生境鸟类群落的鸟类数量级、鸟类群落的物种多样性、鸟类群落间的相似性进行了比较分析,其结果表明:1)国家级保护鸟类在原始林中最多,次生林中最少;我国特有种则是次生林中最多,人工林中最少。2)鸟类群落Shannon-Wiener物种多样性指数原始林最高,人工林最低。3)原始林和次生林之间的B ray-Curtis相似性指数最高,原始林和人工林之间相似性指数最低。     

四川老君山自然保护区的鸡形目种群密度研究

2006年4月~5月,对四川省老君山自然保护区鸡形目鸟类种群的鸣叫雄鸟的密度进行了调查。调查发现了4种鸡形目鸟类:灰胸竹鸡(Bambusicola thoracica)、白腹锦鸡(Chrysolophus amherstiae)、四川山鹧鸪(Arborophila rufipectus)和红腹角雉(Tragopan temminckii)。采用鸣叫计数的方法,在调查区域的3种生境(原始林、人工林和次生林)中记录了鸣叫雄鸟的数量和距调查点的距离。应用距离取样法对数据的计算估计,4种鸡形目鸟类的鸣叫雄鸟在调查区域的密度(只/km2)分别为20.19±6.07、1.48±0.46、4.24±0.60和11.19±2.97。在原始林、人工林和次生林3种生境的鸡形目鸟类密度,灰胸竹鸡分别为7.19±4.19、26.89±8.92和17.79±9.49;白腹锦鸡密度分别为0.74±0.43、2.92±1.42和1.19±0.58;四川山鹧鸪密度分别为7.94±0.99、1.99±1.63和3.06±0.60;红腹角雉密度分别为17.66±5.98、0和12.58±4.85。鸡形目鸟类群落Shannon-Weiner物种多样性指数和Pielou均匀度指数大小依次均为次生林>人工林>原始林,Simpson优势度指数大小则相反。     

四川省三个自然保护区的鱼类资源及保护

2002年7-9月,分别调查了四川美姑大风顶国家级自然保护区、米亚罗自然保护区和泗耳自然保护区的鱼类资源。在这三个保护区共采集鱼类16种。其中,大风顶保护区6种,米亚罗保护区8种,泗耳保护区7种。分析了各保护区鱼类的资源现状．并提出了相应的保护建议。     

花蓟马Frankliniella bispinosa的生长繁殖特性及种群动态研究(英文)

本文提出一种用香蒲 (Typhadomingensis)花粉饲养花蓟马 (F .bispinosa)的方法 ,恒温饲养表明 ,在1 5℃时 ,该蓟马的世代历期长达 3 7 5d ,雌成虫平均寿命为 3 0d ;在 2 0℃和 2 5℃恒温下 ,世代历期分别为1 8 9和 1 3 8d ,雌成虫寿命分别为 2 9 0和 2 3 3d。平均产卵量在 2 5℃时达到最高 (1 2 3 2头 雌 ) ,而在其他几种恒温下产卵量显著减少。在佛罗里达南部 ,终年可见该蓟马在鬼针三叶草 (BidenspilosaL .)花上发生 ,而种群高峰期在三月中旬到四月初 ,平均每朵花中蓟马成虫数最高时可达 48 7头。     

长江合江江段岩原鲤种群遗传多样性的AFLP分析

用9对引物对采自长江上游合江江段的岩原鲤种群的14个个体进行了选择性扩增片段长度多态性研究,共检测出AFLP位点755个,平均每对引物扩增出84个位点,其中多态性位点354个,占46.89%。个体间的遗传距离为0.1061~0.2846,平均遗传距离为0.1793±0.0337。种群平均杂合度为0.1768。与其它一些鱼类比较表明,岩原鲤长江合江种群的遗传多样性可能不够丰富。