关键词： Fleshy fruit   Frugivore   DNA barcoding   Swida controversa  

摘要： Birds and mammals are important seed dispersers of fleshy-fruited plants. Although their behaviors are different, they frequently consume the same species. Thus to understand the dispersal of fleshy-fruited plants, the contribution of birds and mammals to seed dispersal has to be evaluated. Besides, within birds or mammals, some species may functionally different from others. In this study, we examined seed dispersal of the fleshy-fruited tree Swida controversa focusing on the difference between two frugivore groups (birds and mammals), and differences between species within groups. Collected seeds and S. controversa trees were identified using simple sequence repeat (SSR) genotyping, thus enabling to determine the distance between mother tree and dispersed seeds. The avian species were identified by DNA barcoding of feces, whereas the mammalian species were identified by the shape and smell of feces. Most seeds that fell near or under the maternal trees were dispersed by birds, resulting in short seed dispersal distances (average, 13 m). DNA barcoding detected five taxa of avian dispersers. No differences were detected in seed dispersal distance by different avian taxa (i.e., the distance between dispersed seeds and their maternal trees within the research plot);however the rate of seed immigration from outside the research plot by some avian taxa varied significantly. The seed dispersal distance by mammals was significantly further (127 m;min > 50 m) than that by birds. Additionally, immigrated seeds accounted for approximately two-thirds of mammal-dispersed seeds, indicating that these seeds were from outside the research plot, and that mammals significantly contributed to the long-distance seed dispersal of S. controversa. No differences in seed dispersal distance were detected between different mammalian taxa. Overall, this study revealed that birds and mammals show clearly different seed dispersal patterns, and thus, they play different roles in the regenerati

关键词： drainage   plant-soil interactions   soil water potential   stress   tree cover   tree-grass dynamics   tropical savannas  

摘要： 1. Although there is a well-known association between tree cover and soil texture in savannahs, the hydrological drivers of tree cover variation have not been systematically explored, particularly in parallel with factors such as fire, herbivory, and tree-grass interactions. The relationship between hydrological factors and tree cover is important for resolving the relative contribution of bottom-up versus top-down factors in structuring savannah vegetation. 2. We quantified soil moisture dynamics across eight 1-km transects spanning tree cover gradients from open to woody savannah in Serengeti National Park in Tanzania using soil moisture sensors coupled with dataloggers. We mapped tree cover at two spatial scales through supervised classification of high-resolution satellite imagery. We simultaneously produced water retention curves in open and woody habitats within each transect to compare soil hydrological properties and to convert volumetric water content (theta) from dataloggers to plant-available water over the course of an annual cycle. We also quantified grass biomass at 100 locations per transect, estimated fire frequency from MODIS satellite data, and quantified herbivore occupancy with paired camera traps situated in open and woody habitats within each transect. 3. We found a positive relationship between tree cover and soil moisture drainage rate, and found that open habitats had more negative water potentials than woody habitats for a given value of theta. In contrast, we found no evidence for a consistent relationship between grass biomass or fire frequency and tree cover. We found evidence for higher browser occupancy in woody than open habitats, but no habitat effects on herbivores as a group (browsers plus grazers), suggesting that herbivory is unlikely to be the dominant factor explaining variation in tree cover. 4. Synthesis. Our results suggest that variation in tree cover is partly driven by hydrological (edaphic) factors unrelated to fire, her

关键词： Cutting and harvesting in strips   Arthropod guilds   Commercial plantation   Nothofagus obliqua  

摘要： Sustainable forest management aims to both enhance biodiversity and tree productivity. However, trade-offs may exist between these objectives, e.g. arthropod diversity and associated arthropod herbivory can reduce tree growth and survival. Tree productivity and biodiversity may also show non-linear responses to management intensity, making applied recommendations even more challenging. We studied the effects of harvesting intensity for firewood extraction in a northern Patagonian forest (Argentina) on leaf damage diversity (as a proxy of arthropod folivore diversity), leaf damage frequency, growth and survival of planted trees of Nothofagus obliqua for timber purpose. We randomly applied four levels of harvesting intensity (0, 30, 50, and 70% of basal area removal) in experimental plots and we followed the responses on the focal planted tree species during two growing seasons. After harvesting, air temperature and photosynthetic active radiation increased, while relative humidity decreased, with harvesting intensity. leaf damage diversity and frequency showed non-linear responses to harvesting intensity, both achieving its highest values at intermediate harvesting intensities (30% and 50% of basal area removal). Such responses were consistent for contrasting feeding guilds, using different diversity indices, and during the two study growing seasons. Interestingly, leaf damage diversity and frequency were positively and strongly correlated across the plots. Despite great leaf damage frequency (around 45% of the leaves were damaged), plant survival was also highest at intermediate harvesting intensities during the two years. Planted trees also grew more at intermediate harvesting intensities during the second year, but increased linearly with harvesting intensity during the first year. Hence, at intermediate harvesting intensity, no trade-off was observed between arthropod biodiversity and planted tree sapling survival and growth. In northern Patagonia, trees may face

关键词： 感染性疾病   动物模型   应用研究  

摘要： 树鼩是一种非人类灵长类动物,树鼩全基因组测定显示出与人类高度同源性。从感染性疾病的角度来看,树鼩易受非人类宿主病原体的感染,表现出类似于人类感染的临床症状,使它们成为研究感染性疾病的理想的实验动物模型。在这里,我们对树鼩(Tupaia)在感染性疾病动物模型中的应用进行综述。

关键词： amber   Araneae   mass extinctions   molecular clock   phylogeny   systematics  

摘要： Studies in evolutionary biology and biogeography increasingly rely on the estimation of dated phylogenetic trees using molecular clocks. In turn, the calibration of such clocks is critically dependent on external evidence (i.e. fossils) anchoring the ages of particular nodes to known absolute ages. In recent years, a plethora of new fossil spiders, especially from the Mesozoic, have been described, while the number of studies presenting dated spider phylogenies based on fossil calibrations increased sharply. We critically evaluate 44 of these studies, which collectively employed 67 unique fossils in 180 calibrations. Approximately 54% of these calibrations are problematic, particularly regarding unsupported assignment of fossils to extant clades (44%) and crown (rather than stem) dating (9%). Most of these cases result from an assumed equivalence between taxonomic placement of fossils and their phylogenetic position. To overcome this limitation, we extensively review the literature on fossil spiders, with a special focus on putative synapomorphies and the phylogenetic placement of fossil species with regard to their importance for calibrating higher taxa (families and above) in the spider tree of life. We provide a curated list including 41 key fossils intended to be a basis for future estimations of dated spider phylogenies. In a second step, we use a revised set of 23 calibrations to estimate a new dated spider tree of life based on transcriptomic data. The revised placement of key fossils and the new calibrated tree are used to resolve a long-standing debate in spider evolution - we tested whether there has been a major turnover in the spider fauna between the Mesozoic and Cenozoic. At least 17 (out of 117) extant families have been recorded from the Cretaceous, implying that at least 41 spider lineages in the family level or above crossed the Cretaeous-Paleogene (K-Pg) boundary. The putative phylogenetic affinities of families known only from the Mesozoic sugges

关键词： agile wallaby   feral bovines   fire   macropods   wallaroo  

摘要： Australian savannas lack native megaherbivores (>500 kg body mass), but since the commencement of European colonisation in the 19th century bovine livestock, such as cattle (Bos sp.) and water buffalo (Bubalus bubalis), have established large feral populations that continue to geographically expand. The largest extant native herbivores are marsupials in the family Macropodidae (henceforth 'macropods': common wallaroo, Osphranter robustus [c. 40 kg];antilopine wallaroo, O. antilopinus [c. 35 kg] and agile wallaby, Notamacropus agilis [c. 20 kg]). These species occur at low densities, with evidence that some species are in decline, the cause of which remains uncertain. We tested the hypothesis that bovines and macropods compete for nutritious forage in the North Kimberley, Western Australia by using carbon isotope analysis of feral cattle and native macropod dung (as a proxy for the relative contribution of C-4 grass to their diet) and nutrient analysis of standing herbaceous biomass. Grass consumption varied between macropod species and was highest in larger wallaroo species and lowest in the smaller agile wallaby reflecting its broader diet. Grass consumption by wallaroos was maximal on fertile sites. The relative abundance of grass in the diet of cattle was lowest in the middle of the dry season with an interaction between fire and substrate fertility where grass consumption was highest on fertile sites, particularly those recently burnt. Grass consumption by cattle and wallaroos was negatively correlated with fibre content of live biomass, which was lowest on fertile and burnt sites. Introduced bovines shift their diets to non-grasses as quality of herbaceous biomass declines with increasing fibre content, and by contrast, the largest macropod herbivores do not have this dietary flexibility. We conclude a plausible mechanism for the success of bovines and the decline of large macropods in Australian savannas is competition for nutritious grass that is abundant imm

关键词： Neotropical savannas   Exotic grass   Diversity loss   Invertebrates   Stable isotopes   Mixing model  

摘要： Much of the Brazilian savanna (known locally as the Cerrado) has been converted to pasture of African C4 grasses (exotic pastures) for livestock production. The resulting habitat simplification and decreased resource availability may be significant factors underlying the impact on some soil arthropod groups, although it is still unclear how the different soil groups respond to this impact in the Brazilian savanna. We sampled epigeic arthropods in exotic pastures, adjacent woodland savanna fragments (cerrado sensu stricto), and savanna-pasture boundaries to investigate the impact of pasture on their diversity and activity, identifying the arthropods that contribute most to the between-habitat dissimilarities and those most vulnerable to pasture implementation. We also estimated the contribution of native and exotic plants to the diets of frequently observed arthropods in each habitat using carbon and nitrogen stable isotope analysis. We found lower richness and diversity of epigeic arthropods in pastures, where we also observed decreased activity of predator groups, whereas the activity of Symphypleona and Poduromorpha springtails increased. Springtail orders and Myrmicinae morphospecies were the main contributors to the between-habitat dissimilarities. Staphylinidae, Ptiliidae, and Zodariidae morphospecies seem to be vulnerable to exotic pastures. Our isotopic models show that woodland savanna arthropods feed preferentially on native C3-plant sources, while also showing signs of exotic C4 sources in their diet. These outcomes indicate that foraging or dispersal events may occur between habitats since arthropods captured in pastures also show signs of native sources in their diet.

关键词： Arterial stiffness   Blood pressure   Carica papaya L.   Hypertension   Pulse wave velocity  

摘要： Objectives: Hypertension is defined as an increase in systolic and/or diastolic blood pressure of more than 140/90 mmHg. Epidemiological studies showed that there is a relationship between hypertension and the incidence of arterial stiffness, especially in the elderly. Blood pressure management aims to prevent damage to various target organs such as the heart, brain, kidneys, eyes and peripheral arteries. Papaya leaves (Carica papaya L.) have been known empirically to treat hypertension. This study aimed to determine the effect of papaya leaves processed into Nori preparation on blood pressure and arterial stiffness. Methods: This study was carried out on animal models of male Wistar rats induced hypertension. A total of 30 male-Wistar rats were randomly divided into 6 groups consisting of control negative group and control positive group (received drug carriers), the group received captopril 2.5 mg/kg and groups received Nori of papaya leaves 5, 10 and 20% in their diet. All groups except the control negative group received 66% fructose in their food for 21 days. Parameters measured were systolic and diastolic blood pressure, pulse wave velocity (PWV) on days 0, 7, 14 and 21 after treatment. Results: The group received Nori 10% showed normalize both systolic and diastolic blood pressure and a decreased in arterial stiffness compared to the group received captopril (p>0.05). Conclusion: It can be concluded that papaya leaves in Non preparation is effective as an antihypertensive and reduced arterial stiffness.

关键词： 流感病毒   跨种属感染   致病特性   免疫机制  

摘要： 目的:　　甲型流感病毒(influenzaAvirus，IAV)具有宿主范围广、型别多、易变异、传播迅速等特点，常导致流感反复季节性局部流行甚至世界大流行，且部分型别可跨种属传播至人，给人类健康造成极大威胁。动物模型对于研究疾病的感染传播过程、发病机制、宿主抗病免疫机制以及评价新型药物和疫苗的效果及安全性等极为重要。目前已尝试建立了多种流感病毒动物模型，但各有利弊，迄今尚未有十分理想的流感病毒动物模型。树鼩(Tupaiabelangeri，treeshrew)在亲缘关系和种系发育上与人类非常接近，是灵长类动物的旁亲，基因组测序结果也证实树鼩与灵长类具有很高的亲缘性。因其体型小，生长繁殖快，驯养条件及成本较黑猩猩、猴类低，且其生理特征、解剖特点、神经发育、免疫、生化代谢和心理压力等方面与人类高度相似，利用树鼩作为多种疾病的动物模型研究日渐受到极大关注。迄今国内外已有用树鼩成功建立人H1N1亚型流感病毒以及H9N2、H5N1、H7N9亚型禽流感病毒感染模型的案例，但尚未利用树鼩模型对具有感染人潜能的低致病性猪和陆禽流感病毒的致病、感染和免疫特征等进行详细研究。　　为了阐明具备感染人潜能的低致病性猪和陆禽流感病毒的致病机制、免疫特点，以及跨种属感染的潜力，为流感大流行的防控和治疗提供更充分的策略依据，本研究选用前期证实可体外感染猪和人肺组织、体内可未经适应感染小鼠引起病变的具有感染人潜力的两株不同种属来源的IAV:基因组整合了2009新甲型H1N1大流行流感病毒(pdm/09)基因片段的新现H3N2亚型猪流感病毒（简称SW2783）和我国家禽中呈主要流行的陆禽鸡H6N6亚型禽流感病毒（简称ZZ346），以树鼩作为实验动物模型，观察两株流感病毒的致病性、免疫特征及跨种属感染的潜力;利用高通量深度测序和生物信息学分析方法，获得SW2783感染树鼩呼吸道组织的mRNA表达谱，从分子水平较全面分析动物IAV感染与宿主免疫相关mRNA表达情况，为进一步探讨具有感染人潜能的低致病性动物流感病毒与宿主相互作用机制打下坚实基础，同时也为进一步开发树鼩在抗病毒药物、疫苗效果及安全性评价等方面提供理论依据;另外，为深入研究流感病毒等病原体感染树鼩后的免疫应答及免疫病理机制奠定分子检测基础，本研究还探讨了人、小鼠和大鼠三种不同物种抗体芯片检测树鼩抗感染免疫相关分子的可行性，为解决目前缺乏树鼩相关分子检测试剂难题提供参考。　　方法:　　1.建立SW2783和ZZ346树鼩呼吸道组织体外感染模型，同时以pdm/09疫苗株CA09（简称CA09）和水禽鸭流感病毒H9N2亚型（简称ST3208）为参考病毒株，采用病毒血凝试验(HA)、半数组织细胞感染试验(TCID50)、免疫组化等方法观察4种病毒株对树鼩体外呼吸道组织的感染和复制能力及致病性特征。　　2.建立SW2783和ZZ346树鼩体内感染模型，通过HA、TCID50、HE染色、免疫组化、实时定量PCR等实验方法观察两种不同种属来源低致病流感病毒体内感染树鼩的能力、致病特征及抗病毒免疫分子的变化情况。　　3.利用转录组高通量测序技术(RNA-seq)检测SW2783体内感染树鼩后第3d、5d、7d鼻甲组织中差异表达mRNA，并结合生物信息学方法对其进行GO和KEGG富集及蛋白质互作网络(PPI)分析，观察mRNA差异表达谱特征以及其变化趋势。　　4.采用人、小鼠和大鼠三个物种抗体芯片检测树鼩脾细胞中抗感染相关免疫分子，探讨采用非树鼩种属特异性抗体检测树鼩相应分子的可行性。　　结果:　　1.4株流感病毒未经适应性培养均能体外感染树鼩呼吸道组织，但感染能力存在差异。新现H3N2亚型猪流感病毒SW2783株和陆禽H6N6亚型鸡流感病毒ZZ346株对树鼩体外上呼吸道鼻甲、气管组织具有较好的感染能力(TCID50)，SW2783复制能力(HA)较ZZ346强;人pdm/09疫苗株CA09也可在树鼩呼吸道组织中复制，但其复制能力相对较弱;而鸭流感病毒株ST3208虽然也能感染树鼩呼吸道组织，但显现出有限的感染能力。　　***2783和ZZ346未经适应性培养均可体内感染树鼩，显现出一定的致病性，但感染能力(TCID50)、病理变化及临床症状相对较轻，类似于人类普通流感感染，其中SW2783感染能力强于ZZ346，提示其可能进化成具有较好结合人型SAα2，6-Gal受体的能力而具有跨种属感染人的潜能。　　***2783和ZZ346感染树鼩后第3d、5d、7d抗病毒及炎症效应分子Mx1、MDA5、TNF-α、IL-6、MCP-1、IP-10、IFN-γ、IL-10等表达上调，提示感染早期启动有效抗病毒固有免疫应答;感染后第7d，部分动物产生流感病毒特异抗体，第14d所有动物均产生流感病毒特异抗体，提示流感病毒感染树鼩后