关键词： 树鼩   资源开发   标准化研究  

摘要： 树鼩(Tupaia belangeri)作为人类疾病动物模型,被应用于人类医学实验研究的多个领域,如各种类型的病毒性肝炎模型,流感病毒、登革热病毒、轮状病毒、疱疹病毒模型,糖尿病、胆结石、癌症病模型。但是,目前我国用于实验研究的树鼩几乎全都来自野外,对它们的微生物学、寄生虫学、遗传学、环境学等质量标准没有进行控制,它们本身携带的许多病原体会对实验结果的准确性造成影响,这既不符合国家对实验动物许可证管理的要求,也不利于我国实验动物科技工作与国际接轨的发展要求。因此,应该同步开展树鼩资源的开发利用和标准研究,使之纳入实验动物许可证的有效监控和管理,改变目前使用在前、质量控制标准研究在后的被动局面。

关键词： HBx   突变Kras   睾丸生精小管内注射   脂质体   精原细胞   转基因树鼩  

摘要： 目的在构建重组质粒pcDNA3.1-HBx和pEGFP-N1-Kras的基础上,采用直接注射的方法,将脂质体包裹的重组质粒注入动物睾丸中,探讨利用睾丸内生精小管微注射精子载体法建立转HBx、突变Kras基因树鼩的可行性,为建立转HBx、突变Kras基因树鼩肝癌动物模型并进一步研究两种基因在肝细胞癌发生发展过程中的作用打下基础。 方法首先用多聚酶链式反应(PCR)扩增含NheⅠ和KpnⅠ酶切位点的Kras基因序列,对pEGFP-N1载体及Kras基因PCR产物双酶切,用连接酶将两者连接并转化大肠杆菌DH5α,筛选阳性克隆,并对其进行双酶切和测序鉴定,构建Kras基因真核表达载体pEGFP-N1–Kras;成年雄雌树鼩按1:1或1:2配对,根据动物间的适应和受孕情况调整成相对固定的繁殖对。给所有动物建立档案,记录树鼩的生产情况,计算母树鼩的总产仔数、平均年产仔数及平均每次妊娠的合笼天数。记录仔动物的每日体重、进食量和健康情况。对仔树鼩用三种方法进行喂养,即配方乳喂养、被动和主动母乳喂养。16只雄性成年树鼩随机分为pcDNA3.1-HBx组、pEGFP-N1-Kras组、pcDNA3.1-HBx + pEGFP-N1-Kras组和生理盐水对照组,利用脂质体2000包裹已构建的pcDNA3.1-HBx和pEGFP-N1-Kras重组质粒,按3:1比例混合(V/W),DMEM稀释后按分组用微量注射器多位点注射入16只雄性树鼩睾丸,每周一次,连续注射四次后再隔三周与成年雌性树鼩合笼自然交配。对合笼交配后4个月内生产的仔树鼩进行肝活检,提取活检肝组织总DNA,PCR技术对基因整合进行鉴定,免疫组化检测其蛋白表达情况。C57BL/6小鼠转基因试验方法同树鼩,剪取一周龄仔鼠尾巴提取总DNA,PCR检测目的基因。 结果双酶切pEGFP-N1-Kras后,琼脂糖电泳可分别见到大小约为567bp的片段和几kb的大片断,说明Kras亚克隆入pEGFP-N1,经序列测定其含有完整的Kras基因片段;20个月的实验期内共进行三次转基因后的雄性树鼩,均具有正常的繁殖能力,三轮实验观察期内共生产仔树鼩128只,其中成活58只。仔树鼩存活率为45.3%;PCR检测128只仔树鼩肝、肾等组织中的HBx基因,其中4只为阳性(单独注射组3只,联合注射组1只)。PCR产物经DNA测序证实为HBx基因。阳性率为3.57%。EGFP基因均为阴性。经转基因后的小鼠12个月的观察期内共获得HBx基因阳性动物3只(单独注射组2只,联合注射组1只),EGFP基因阳性动物1只(联合注射组)。对活检肝组织进行常规HE染色和免疫组化检测,显示3只树鼩(E9478、E9242、E9256)部分肝细胞有HBxAg阳性颗粒分布。两只树鼩(E9260、E9252)活检肝组织出现EGFP蛋白表达。 结论成功构建了真核表达载体pEGFP-N1-Kras;睾丸内注射精原细胞介导法构建转HBx基因树鼩动物模型是可行的,用此方法建立转突变Kras基因树鼩是否可行还需进一步研究。

关键词： Aceria parapopuli   cryptic speciation   foundation species   host race formation   hybridization   Populus   PLANT HYBRID ZONES   NATURAL INTERSECTIONAL HYBRIDIZATION   HOST-RACE FORMATION   GENETIC DIFFERENTIATION   POPULUS SALICACEAE   SECTIONS AIGEIROS   REPRODUCTIVE ISOLATION   SYMPATRIC SPECIATION   PHYTOPHAGOUS INSECTS   POPULATION-STRUCTURE  

摘要： Few studies have investigated the roles that plant hybridization and individual plant genotype play in promoting population divergence within arthropod species. Using nrDNA sequence information and reciprocal transfer experiments, we examined how tree cross type (i.e., pure Populus angustifolia and P. angustifolia x P. fremontii F-1 type hybrids) and individual tree genotype influence host race formation in the bud-galling mite Aceria parapopuli. Three main findings emerged: (1) Strong genetic differentiation of mite populations found on pure P. angustifolia and F-1 type hybrids indicates that these mites represent morphologically cryptic species. (2) Within the F-1 type hybrids, population genetic analyses indicate migration among individual trees; however, (3) transfer experiments show that the mites found on heavily infested F-1 type trees perform best on their natal host genotype, suggesting that genetic interactions between mites and their host trees drive population structure, local adaptation, and host race formation. These findings argue that hybridization and genotypic differences in foundation tree species may drive herbivore population structure, and have evolutionary consequences for dependent arthropod species.

关键词： 动物园   事业   实践活动   解放思想  

摘要： 根据石园党字[2008]10号文《关于围绕“三年大变样”开展“双创双树”主题实践活动的实施意见》，结合我园边建设，边开放的实际，紧紧围绕突出创新，突出实践，突出标准，突出解决实际问题这“四突出”，认真组织动员，学习传达，力求以解放思想的新境界开创动物园事业发展的新局面。

关键词： climate change   eucalypt   endemic mammal   rainforest   tree hollow   Wet Tropics Bioregion   GLIDER PETAUROIDES-VOLANS   VERTEBRATE FAUNA   NEST BOXES   SOUTHEASTERN AUSTRALIA   NATURAL CAVITIES   TREE SWALLOWS   SELECTION   FORESTS   AVAILABILITY   TEMPERATURE  

摘要： Tree cavities are an important shelter site for a variety of vertebrate species, including birds, reptiles and mammals. Studies indicate that in most taxa favoured tree hollows are those in larger trees and higher from the ground, generally thought to be related to decreased predation risk and a more optimal thermal environment. However, neither of these ideas has been tested definitively. Here, we investigate the microclimate of daytime den sites in tree hollows of common brushtail possums in tropical northern Australia. We compare tree and hollow characteristics of dens known to be used by possums, and those not known to be used, to determine whether possums choose trees with microhabitats with a more favourable daytime microclimate. Possums chose to den in tree hollows which were on average 1.6 degrees C cooler during the day, and were more buffered from temperature extremes, than other potential den locations. Important factors explaining daytime temperatures between hollows included height of the hollow, entrance width and tree diameter. Tropical arboreal marsupials have been identified as being particularly vulnerable to climate change and there are calls to identify and preserve natural refuges, such as tree hollows, which could buffer them from extreme temperatures. Our results highlight the value of older, larger hollow-bearing trees as refuges from extreme temperature, the importance of which may become critical for some temperature-sensitive species under the combined effects of continuing habitat loss and climate change.

关键词： Acacia drepanolobium   Africa   Laikipia   Kenya   landscape of fear   optimal foraging   predator avoidance   structural equation modeling   tree-grass interactions   ungulates   woody encroachment   AFRICAN SAVANNAS   SEMIARID SAVANNA   NATIONAL-PARK   PREDATION   BEHAVIOR   PREY   SIZE   VIGILANCE   ECOLOGY   WOLVES  

摘要： Herbivores choose their habitats both to maximize forage intake and to minimize their risk of predation. For African savanna herbivores, the available habitats range in woody cover from open areas with few trees to dense, almost-closed woodlands. This variation in woody cover or density can have a number of consequences for herbaceous species composition, cover, and productivity, as well as for ease of predator detection and avoidance. Here, we consider two alternative possibilities: first, that tree density affects the herbaceous vegetation, with concomitant "bottom-up'' effects on herbivore habitat preferences; or, second, that tree density affects predator visibility, mediating "top-down'' effects of predators on herbivore habitat preferences. We sampled sites spanning a 10-fold range of tree densities in an Acacia drepanolobium-dominated savanna in Laikipia, Kenya, for variation in (1) herbaceous cover, composition, and species richness; (2) wild and domestic herbivore use; and (3) degree of visibility obstruction by the tree layer. We then used structural equation modeling to consider the potential influences that tree density may have on herbivores and herbaceous community properties. Tree density was associated with substantial variation in herbaceous species composition and richness. Cattle exhibited a fairly uniform use of the landscape, whereas wild herbivores, with the exception of elephants, exhibited a strong preference for areas of low tree density. Model results suggest that this was not a response to variation in herbaceous-community characteristics, but rather a response to the greater visibility associated with more open places. Elephants, in contrast, preferred areas with higher densities of trees, apparently because of greater forage availability. These results suggest that, for all but the largest species, top-down behavioral effects of predator avoidance on herbivores are mediated by tree density. This, in turn, appears to have cascading effect

关键词： seed dispersal and predation   fragmentation   regeneration   exclosure experiments   Madagascar   SEED DISPERSAL   DECIDUOUS FOREST   TROPICAL FORESTS   CONSEQUENCES   DIVERSITY   COMMUNITIES   ANIMALS   REGENERATION   DYNAMICS   ECOLOGY  

摘要： The objective of this study was to examine how the processes of seed dispersal and seed predation were altered in forest fragments of the dry forest of Madagascar, where the usual seed dispersers and vertebrate seed predators were absent, using a lemur-dispersed tree species (Strychnos madagascariensis; Loganiaceae) as an example. We then assessed how the changes in vertebrate community composition alter the regeneration pattern and establishment of this tree species and thus, ultimately, the species composition of the forest fragments. By using size-selective exclosures, data from forest fragments were compared with results from continuous forest where vertebrate dispersers and predators were abundant. Visits to the exclosures by mammalian seed predators were monitored with hair traps. In the continuous forest up to 100% of the seeds were removed within the 7 days of the experiments. A substantial proportion of them was lost to seed predation by native rodents. In contrast, practically no predation took place in the forest fragments and almost all seeds removed were dispersed into the safety of ant nests by Aphaenogaster swammerdami, which improves chances of seedling establishment. In congruence with these findings, the abundance of S. madagascariensis in the forest fragments exceeded that of the continuous forest. Thus, the lack of vertebrate seed dispersers in these forest fragments did not lead to a decline in regeneration of this animal-dispersed tree species as would have been expected, but rather was counterbalanced by the concomitant demise of vertebrate seed predators and an increased activity of ants taking over the role of seed dispersers, and possibly even out-doing the original candidates. This study provides an example of a native vertebrate-dispersed species apparently profiting from fragmentation due to flexible animal-plant interactions in different facets, possibly resulting in an impoverished tree species community.

关键词： MULTIPLE SEQUENCE ALIGNMENT   BAYESIAN-INFERENCE   ARTHROPODS   EUKARYOTES   ECDYSOZOA   EVOLUTION   SELECTION   POSITION   DATABASE   CLADE  

摘要： Long-held ideas regarding the evolutionary relationships among animals have recently been upended by sometimes controversial hypotheses based largely on insights from molecular data(1,2). These new hypotheses include a clade of moulting animals (Ecdysozoa)(3) and the close relationship of the lophophorates to molluscs and annelids (Lophotrochozoa)(4). Many relationships remain disputed, including those that are required to polarize key features of character evolution, and support for deep nodes is often low. Phylogenomic approaches, which use data from many genes, have shown promise for resolving deep animal relationships, but are hindered by a lack of data from many important groups. Here we report a total of 39.9 Mb of expressed sequence tags from 29 animals belonging to 21 phyla, including 11 phyla previously lacking genomic or expressed-sequence-tag data. Analysed in combination with existing sequences, our data reinforce several previously identified clades that split deeply in the animal tree (including Protostomia, Ecdysozoa and Lophotrochozoa), unambiguously resolve multiple long-standing issues for which there was strong conflicting support in earlier studies with less data (such as velvet worms rather than tardigrades as the sister group of arthropods(5)), and provide molecular support for the monophyly of molluscs, a group long recognized by morphologists. In addition, we find strong support for several new hypotheses. These include a clade that unites annelids (including sipunculans and echiurans) with nemerteans, phoronids and brachiopods, molluscs as sister to that assemblage, and the placement of ctenophores as the earliest diverging extant multicellular animals. A single origin of spiral cleavage (with subsequent losses) is inferred from well-supported nodes. Many relationships between a stable subset of taxa find strong support, and a diminishing number of lineages remain recalcitrant to placement on the tree.

关键词： 中国科学家   动物化石   生物进化   中国地质科学院   地质研究所   学术论文  

摘要： 近日出版的《地质学报》（英文刊）2008年第1期上，来自中国地质科学院地质研究所的两篇学术论文分别对一块5．8亿年前的早期动物化石以及一块1．24亿年前的原始鸟类化石进行了分析和介绍，生物进化树上又增添了两种由中国科学家发现并命名的古代动物。

关键词： 树胸   模型   动物   肝炎病毒  

摘要： 肝炎的的大范围流行已成为国内外关注的重要公共卫生问题之一。甲肝、乙肝虽已有疫苗,但不能忽视未来由于病毒变异所带来的威胁。丙肝目前尚未发现非常有效的疫苗,且丙肝的病理学机制也尚未完全清晰,主要原因是缺乏理想的动物模型。树属于低等灵长类动物。研究发现,他对很多人类疾病易感,所以建立肝炎树动物模型成为现在肝炎研究的一个热点。本文介绍了各型肝炎主要是甲、乙、丙型肝炎研究中建立树动物模型的国内外进展情况及存在的问题。