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91.
五龙鹅MHC ClassⅠ基因克隆及同源建模研究   总被引:1,自引:0,他引:1  
主要组织相容性复合体(MHC)与动物机体对外源性抗原的免疫应答之间存在关联。从GenBank/DDBJ/EMBL基因库中读取鸡、其他鸟类、爬行类和哺乳类的MHC ClassⅠ基因进行序列分析设计引物, 使用LA-PCR法从五龙鹅的基因组中克隆了MHC ClassⅠ基因序列(DNA序列和mRNA序列GenBank登录号分别为: AM114925和AM114924), 并分析其基因组结构。运用生物信息学技术对测序结果进行分析显示: 基因组DNA由8个外显子和7个内含子组成, 与鸡基因序列同源率为60.8%~64.1%, 与人的同源率为42.9%。分子进化树进一步揭示了五龙鹅与鸡、其他鸟类、爬行类、哺乳类以及人类的进化关系, 同源建模分析发现该基因由氨基末端结构域和羧基末端结构域构成。  相似文献   
92.
1. At a local scale, the species composition, diversity and spatial variation of wetland plant communities are determined primarily by spatial and temporal heterogeneity in their environments. Less is known about variation at a landscape‐level. The floodplain of the Changjiang (Yangtze) River in China includes hydrologically connected, subtropical wetlands with different hydrological characteristics. 2. We examined seed‐bank species composition and richness in marshes of two contrasting hydrological types: permanent marshes, fed by local runoff, and lakeshore marshes more closely connected to the regulated river. Lakeshore marshes are flooded annually to depth of approximately 1 m and during flooding they support an alternate, aquatic vegetation type. The soil seed bank in March was a comparative estimator of species diversity. At the beginning of the growing season it included seeds from both phases of alternating vegetation types associated with the annual hydrological cycle. 3. A regional pool of 101 species was detected in the seed banks of six wetlands associated with the river and its tributaries: 56 occurred in permanent marshes and 59 in lakeshore marshes, with only 15 common to both. Species rarefaction curves indicated that more species occurred in permanent than lakeshore marshes at equal numbers of individuals sampled. However, the more heterogeneous lakeshore seed banks were estimated (Chao 2) to have greater total species richness (81) than permanent marsh (60). 4. Analysis using Sørensen's coefficient of similarity and DCA ordination revealed complex variation, with much greater differences between hydrological types than within them, irrespective of geographical distance. The types also differed significantly in the composition of four functional groups of species. 5. Despite the potential for dispersal of propagules via the annually pulsing river system (hydrochory), at a regional and landscape scale, diversity is maintained largely by large‐scale temporal hydrological heterogeneity and smaller scale spatial and topographic heterogeneity.  相似文献   
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94.
记述西藏自治区蚋属Simulium蚋亚属Simulium 1新种,以陈汉彬教授的名命名为汉彬蚋Simulium(Simulium) hanbini sp. nov.。该新种与Simulium (Simulium) jingfui Cai & An, 2008及Simulium (Simulium)liubaense Liu & An, 2009相似,但该蚋爪无基齿,拉氏器较长,食窦的形状也不同。模式标本保存在北京军事医学科学院医学昆虫标本馆。  相似文献   
95.
实验采用离体血管环灌流模型,观察厚朴叶正丁醇萃取部位对去甲肾上腺素预收缩的内皮完整和去除内皮的家兔离体血管环张力的影响。结果显示:厚朴叶正丁醇萃取部位对内皮完整和去除内皮的血管环在一定剂量内呈现浓度依赖性舒张作用,该作用可能与该部位大量成分———槲皮苷和芦丁有关。从该部位分离得到7个化合物,分别为槲皮苷(1),芦丁(2),紫丁香苷(3),丁香脂素-4,4’-双-O-β-D-葡萄糖苷(4),芥子醛-4-O-β-D-吡喃葡萄糖苷(5),松脂素-4-O-β-D-吡喃葡萄糖苷(6),丁香脂素-4-O-β-D-吡喃葡萄糖苷(7)。其中化合物4和6首次从该种植物中分离得到。  相似文献   
96.
为研究刮膜式分子蒸馏过程的数学模型,选用刮膜式短程蒸馏器,采用液氮制冷对橘皮油进行分离。借助传统精馏中的塔板理论和Langmuir-Knudsen等相关理论,对蒸馏过程进行分析,通过物料衡算,建立刮膜式分子蒸馏过程的数学模型,结合模型分析进料速率、蒸馏温度、蒸发面积等因素对产品纯度及收率、理论级数、理论高度的影响,并与实际实验结果对比,二者的偏差不超过11%,验证了模型的合理性,为分子蒸馏器设计的完善提供了一定的理论基础。  相似文献   
97.
2008年夏季南海北部浮游植物群落结构特征分析   总被引:3,自引:0,他引:3  
根据2008年8月15日—2008年9月7日南海北部调查期间所获得的网采浮游植物资料,对该海域的4个断面共计13个站位的浮游植物群落结构特征进行了研究,包括种类组成、丰度、分布、多样性以及浮游植物群落结构与环境因子之间相关关系等基本状况。本次调查共鉴定出浮游植物4门53属169种(含变种和变型),主要以暖水性、广温性和广布性种为主,其中硅藻门(Bacillariophyceae)37属114种,占总种数的67.4%,甲藻门(Pyrrophyta)12属50种,占总种数的29.6%,蓝藻门(Cyanophyta)2属3种及金藻门(Chrysophyta)2属2种等。浮游植物丰度平均值为18.06×104cells/m3,其中硅藻丰度平均值为55.72×106cells/m3,甲藻丰度平均值为0.81×106cells/m3。调查区域内的优势种包括铁氏束毛藻(Trichodesmium thiebautii),洛氏角毛藻(Chaetoceros lorenzianus),柔弱菱形藻(Nitzschia delicatissima),红海束毛藻(Trichodesmium erythraeum)和菱形海线藻(Thalassionema nitzschioides)。藻类为聚类分析(UPMGA)将站点大致上分为4个生态区(珠江口生态区,吕宋海峡区,琼东上升流区和18°N断面区),结果表明,在地理位置上分布比较相近的站点具有较高的群落结构组成相似性。  相似文献   
98.
目的:探讨成年女性压力性尿失禁患者的心理健康状况,提出护理干预方法。方法:采用SCL-90及自编一般资料,对浏阳市市区80名有压力性尿失禁症状的成年女性进行心理健康自评调查,另80名无压力性尿失禁症状的成年女性为对照。结果:有压力性尿失禁症状的成年女性SCL-90总分、阳性项目数、阳性项目均分及躯体化、人际关系、抑郁、焦虑、敌对、恐怖和精神病性等因子评分均明显高于对照组及常模组(P<0.05)。结论:成年女性压力性尿失禁患者心理健康状况不容乐观,应引起重视,并对其进行护理干预,加强对她们的心理疏通,可以提高疾病的防治效果。  相似文献   
99.
Abstract: Manipulation of forest habitat via mechanical thinning or prescribed fire has become increasingly common across western North America. Nevertheless, empirical research on effects of those activities on wildlife is limited, although prescribed fire in particular often is assumed to benefit large herbivores. We evaluated effects of season and spatial scale on response of Rocky Mountain elk (Cervus elaphus) and mule deer (Odocoileus hemionus) to experimental habitat manipulation at the Starkey Experimental Forest and Range in northeastern Oregon, USA. From 2001 to 2003, 26 densely stocked stands of true fir (Abies spp.) and Douglas-fir (Pseudotsuga menziesii) were thinned and burned whereas 27 similar stands were left untreated to serve as experimental controls. We used location data for elk and mule deer collected during spring (1 Apr-14 Jun) and summer (15 Jun-31 Aug) of 1999–2006 to compare use of treated and untreated stands and to model effects of environmental covariates on use of treated stands. In spring, elk selected burned stands and avoided control stands within the study area (second-order selection; large scale). Within home ranges (third-order selection; small scale), however, elk did not exhibit selection. In addition, selection of treatment stands by elk in spring was not strongly related to environmental covariates. Conversely, in summer elk selected control stands and either avoided or used burned stands proportional to their availability at the large scale; patterns of space use within home ranges were similar to those observed in spring. Use of treatment stands by elk in summer was related to topography, proximity to roads, stand size and shape, and presence of cattle, and a model of stand use explained 50% of variation in selection ratios. Patterns of stand use by mule deer did not change following habitat manipulation, and mule deer avoided or used all stand types proportional to their availability across seasons and scales. In systems similar to Starkey, manipulating forest habitat with prescribed fire might be of greater benefit to elk than mule deer where these species are sympatric, and thus maintaining a mixture of burned and unburned (late successional) habitat might provide better long-term foraging opportunities for both species than would burning a large proportion of a landscape.  相似文献   
100.
Abstract Few data exist regarding suitable feral swine (Sus scrofa) attractants in the United States. We compared species-specific visitation and contact rates of mammals to 11 candidate feral swine attractants at scent stations using motion-sensing digital photography to identify promising attractants. We found feral swine had greater visitation rates to apple and strawberry stations than to control stations. We recommend managers consider using strawberry attractants for feral swine-specific applications. If, however, a general feral swine attractant is needed, then apple, berry, or caramel attractants may perform well.  相似文献   
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