关键词： Alley cropping   Grass strip   Ground dwelling arthropods   Maize   Tree row   Winter cereals  

摘要： Ground dwelling arthropods present in agricultural systems regulate multiple ecosystem services (ES), such as nutrient and carbon cycling and biological pest control. The presence of semi-natural landscape features, such as the tree component of agroforestry systems (AFS), can contribute to functional agrobiodiversity and optimize the delivery of such ES in agricultural landscapes. In temperate AFS, however, potential patterns in abundance and diversity have scarcely been investigated for detritivorous soil dwelling arthropods and only to a limited extent for predatory arthropods. Therefore, we have assessed the abundance and diversity of woodlice (Isopoda), millipedes (Diplopoda), rove beetles (Coleoptera: Staphylinidae) and carabids (Coleoptera: Carabidae) as a function of the distance to the tree row in a set of temperate arable AFS. Abundance and diversity of woodlice and millipedes were significantly higher in the tree rows than in the arable zone. In the case of mature trees, a higher abundance of detritivores was also observed in the arable zone close to the trees. Tree presence did not consistently lead to higher abundance of predatory arthropods, but a limited increase in carabid diversity was observed in the arable zone close to the tree rows. These results indicate that in temperate AFS, the trees and the associated understory vegetation strip contribute to the preservation of arthropod biodiversity and the enhancement of associated ES in the tree rows and in the arable field zone.

关键词： 人诺如病毒   动物模型   树鼩  

摘要： 目的探索通过灌胃攻毒的方法建立树鼩诺如病毒(Human Noroviruses,Hu No Vs)感染动物模型的可行性。方法分别灌胃两组6月龄树鼩攻毒GII.4型Hu No Vs 2010和Sydney株粪便悬液,对照组灌同等体积的PBS(每组5只),攻毒后连续7 d观察体征和腹泻症状,每隔24 h采集粪便应用RT-PCR法检测Hu No Vs RNA,处死树鼩后采集小肠组织,HE染色观察病理变化并应用免疫组化法检测病毒抗原,并对树鼩唾液进行人类组织血型抗原(histoblood group antigen,HBGAs)鉴定分析。结果树鼩经Hu No Vs灌胃攻毒后未出现明显感染症状和腹泻,粪便标本中未检测到Hu No Vs RNA,小肠组织中未检测到Hu No Vs抗原,病理变化不明显,树鼩唾液中HBGAs抗原为阴性。结论树鼩对Hu No Vs不易感原因可能与其不分泌表达HBGAs和普通级饲养繁殖条件等有关,Hu No Vs感染树鼩小动物模型仍有待进一步探索。

关键词： aerial insectivore   antiparasite treatment   brood age   brood size hierarchy   harsh weather   plumage characteristics   Tachycineta bicolor   Tree Swallow  

摘要： Extreme weather events influence the population dynamics of wild animals. For organisms whose food source is affected by environmental conditions, such as aerial insectivorous birds, periods of inclement weather can have devastating effects. Here, we examine predictors of survival of individual nestlings and whole broods in Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) during an extreme, 2-day harsh weather event in central British Columbia, Canada, which co-occurred with experimental reduction of nest ectoparasite loads using an antiparasite drug (ivermectin) or heat-treating nests. A curvilinear relationship existed between survival and brood age such that middle-aged broods were least likely to survive. Survival of broods and nestlings was higher when raised by males with bluer plumage, whereas nestling survival was lower when female parents had brighter and more UV-reflective plumage. Within broods, smaller nestlings had a lower chance of surviving than their larger siblings. Nestlings in broods where half of the offspring received ivermectin injections had significantly higher chances of surviving than nestlings from nonexperimental broods, suggesting that parasite loads can influence survival during inclement weather. Our results identify several factors influencing resiliency of nestlings to harsh weather and are particularly relevant in the context of declining aerial insectivorous bird populations and climate change.

关键词： Shading   Black globe temperature and humidity index   Radiant thermal load   Eucalyptus   Native trees  

摘要： This study aimed to assess solar radiation transmission and animal thermal comfort indexes in two silvopastoral systems established with different tree arrangements in a tropical region. This study was conducted between 2014 and 2017 in two silvopastoral systems, one composed by an established Urochloa (syn. Brachiaria) decumbens pasture with Brazilian native trees planted in triple rows spaced 17 m apart, and another by an established Urochloa (syn. Brachiaria) brizantha (Hochst ex A. Rich.) Stapf %RS Plata' pasture with Eucalyptus urograndis (clone GG100) trees arranged in single rows spaced 15 m apart. In these systems and in a full-sun pasture, photosynthetically active radiation transmission, air temperature, relative humidity, black globe temperature, and wind speed were measured. These variables were used to calculate black globe temperature and humidity index (BGHI) and radiant thermal load (RU). Higher animal thermal comfort was observed in the silvopastoral systems due to changes in the microclimate induced by the trees;notably, a decrease in solar radiation transmission. Fewer hours of potential animal thermal stress (BGHI > 79) were observed in the silvopastoral systems than under the full-sun conditions, with differences up to 3 h per day. The silvopastoral systems presented lower radiant thermal load than the full-sun pasture with differences up to 22% achieved. The assessed silvopastoral systems may help livestock adapt to climate change, since they achieved the limit of BGHI considered to cause stress to animals following an increase of 2.2 degrees C in air temperature, compared with full-sun pastures.

关键词： Acacia robusta   Acacia tortilis   competition   environmental gradients   herbaceous vegetation   plant-animal interactions   plant-available moisture   recruitment limitation  

摘要： 1. Savanna ecosystems span a diverse range of climates, edaphic conditions, and disturbance regimes, the complexity of which has stimulated long-standing interest in the mechanisms that maintain tree-grass coexistence. One hypothesis suggests that tree establishment is strongly limited by one or several demographic bottlenecks at early stages of the tree life cycle. A major impediment to testing this hypothesis is the lack of data on the relative strengths of different bottle-necks across key environmental gradients. 2. To identify demographic bottlenecks that limit early tree establishment (0-18 months), we conducted a series of transplant experiments with two savanna trees species (Acacia robusta and Acacia tortilis) across a natural rainfall and soil fertility gradient in the Serengeti ecosystem, Tanzania. We tested the interactive effects of precipitation, herbivory, seed scarification, grass competition, water limitation, and tree species identity on two key life stages: germination and early seedling survival (0-2 months), and juvenile seedling survival (2-18 months). 3. Germination and early seedling survival increased as a function of rainfall, in the absence of herbivores and when seeds were scarified. Juvenile seedling survival, in contrast, decreased with rainfall but increased in the absence of herbivores. Grass removal had the single strongest (positive) effect on juvenile seedling survival of any treatment. Soil moisture monitoring and grass-addition treatments revealed that grasses negatively affected seedlings in ways that were not necessarily linked to soil moisture. 4. A demographic model combining all effects across early life stages showed that the strength of grass competition on juvenile seedling survival was the key factor limiting early tree establishment. While rainfall had an unexpected opposing effect on the two life stages, the net effect of mean annual precipitation on early tree establishment was positive. 5. Synthesis. Successful tree

关键词： Polyphenolic compounds   Mangiferins   Chlorogenic acids   Flavonoids   Caffeine  

摘要： There are relatively few studies concerning the use of coffee leaves for medicinal purposes and the composition of secondary plant substances. Therefore, we identified and quantitated polyphenolic compounds along with caffeine present in methanol extracts of Coffea arabica leaves from three different regions of Brazil (Ceara, Minas Gerais and Sao Paulo) by HPLC-ESI-MS. In addition, correlations between polyphenolic content of the coffee leaves and antioxidant assays DPPH, FRAP and ORAC were evaluated. Fifteen compounds belonging to three classes of polyphenols (xanthones, chlorogenic acids and flavonoids) along with the alkaloid caffeine were detected. The mean concentration of total polyphenolic compounds in the leaves of C. arabica, harvested from three different regions of Brazil was quite variable. The highest values were detected in the coffee leaves harvested in Minas Gerais (n = 4) at 40.80(13.00) g/kg (SD), followed by coffee leaves harvested in Sao Paulo (n = 20) at 24.79(20.19) g/kg, and the lowest in coffee leaves harvested in Ceara (n = 11) in the Northeast of Brazil at 10.30(5.61) g/kg. The three classes of polyphenols, all showed excellent correlations in the antioxidant assays. Coffee leaf tea, appears to be an excellent functional beverage, with its high content of polyphenolic compounds, which may render positive biologic effects, when inbibed as part of the normal human diet.

关键词： aquatic-terrestrial linkages   stable isotopes   riparian   African clawless otter   Aonyx capensis  

摘要： Animal-mediated nutrient transfer facilitates nutrient cycling in marine, freshwater and terrestrial ecosystems via the deposition of aquatically-derived nutrients such as nitrogen (N) and carbon (C). This mode of nutrient transfer has not been studied in southern African river systems. We investigated nutrient deposition associated with defecation, urination, and scent-marking at latrine sites of a semi-aquatic predator species (African clawless otters Aonyx capensis) in a riparian zone of a Bankenveld savanna ecosystem. We provide a comparison of stable nitrogen isotopes (delta N-15) measured in soil, vegetation and faecal material, between latrine and paired control sites. Latrine sites displayed higher delta N-15 values than the paired non-latrine sites, but only at the area of direct deposition (soil surfaces). This effect dissipated as the distance from direct contact increased, while no significant difference in delta 15N values was detected for sub-surface soil samples. Plants displayed varying trends of enriched delta 15N values between the latrine and paired control sites. These results suggest that several factors and processes such as leaching, mineralization, ammonia volatilization, and nitrogen acquisition influence the nutrient availability within latrine-soil-vegetation systems in riparian zones of African savanna ecosystems.

关键词： KSHV/HHV-8   树鼩   潜伏感染   动物模型  

摘要： 卡波西肉瘤相关疱疹病毒（Kaposi's sarcoma-associated herpesvirus,KSHV）又称人类疱疹病毒8型（Human herpesvirus 8,HHV-8）属于γ疱疹病毒亚科猴疱疹病毒属。KSHV是人类重要的DNA肿瘤病毒,它是诱发卡波西氏肉瘤（Kaposi's Sarcoma,KS）、原发性渗出淋巴瘤（Primary Effusion Lymphoma,PEL）、多中心卡斯特曼病（Multicentric Castleman's Disease,MCD）和炎症细胞因子综合症（KSHV inflammatory cytokine syndrome,KICS）及共感染HIV/AIDS患者高度致瘤死亡的重要病原体。全球每年KSHV新发感染癌症肿瘤患者病例可达34000例。特别是在撒哈拉以南非洲地区,KSHV感染率高达95%并引起超过50%的HIV/AIDS患者死亡。KSHV可以感染多种人源细胞,包括内皮起源细胞、淋巴细胞、上皮细胞和成纤维细胞等。KSHV感染动物模型是研究KSHV潜伏和裂解感染转换、感染组织细胞嗜性、KS致癌与机体免疫应答机制,及开发疫苗和筛选治疗药物必要技术平台。虽然KSHV感染的免疫缺陷小鼠和绒猴的动物模型已成功建立,但仍存在与人类物种差异大和价格昂贵等诸多问题,建立合适的KSHV感染动物模型是当前亟待解决的关键问题。树鼩属低等灵长类动物,与人类进化关系较为密切,已被广泛的应用于人类病毒性疾病研究。因此,我们用树鼩作为感染对象,从体内外不同水平建立KSHV感染树鼩的动物模型。本研究利用iSLK.219病毒株细胞培养体系,培养获得rKSHV.219重组病毒。采用胶原酶和胰酶消化法分离出原代肝窦内皮细胞、真皮成纤维细胞、肾上皮细胞、血管内皮细胞、肺上皮细胞和外周血淋巴细胞树鼩六种原代细胞,经鉴定后进行体外培养。用KSHV感染树鼩原代细胞,经荧光观察和流式细胞仪检测发现,KSHV病毒能够高效感染树鼩原代肾上皮细胞（GFP表达比率达97%）,对其他原代细胞的感染性依次为:树鼩原代肾上皮细胞（TSKEC）>HEK293T（TSKEC vs HEK293T,p<0.05）>树鼩原代肝窦内皮细胞（TSKEC vs TSLSE,p<0.01）>树鼩原代肺上皮细胞（TSKEC vs TSLEC,p<0.05）>树鼩原代血管内皮细胞（TSKEC vs TSVEC,p<0.001）>树鼩原代真皮成纤维细胞（TSKEC vs TSSFC,p<0.001）>树鼩外周血淋巴细胞（TSKEC vs TSPBMC,p<0.001）。与啮齿类大鼠和兔原代肾细胞对KSHV病毒易感性相比较,树鼩原代肾上皮细胞具有显著的种属优势。对感染的树鼩肾上皮细胞感染特性研究表明,TSKEC胞内病毒粒子在感染24 h后其病毒复制、蛋白表达和病毒滴度达到最大值。对感染TSKEC进行细胞传代培养和病毒检测发现,KSHV可以长期潜伏感染原代TSKEC,每个代次都有LANA蛋白表达,而裂解期蛋白ORF26仅可在早期P0和P1代表达。进而,我们选用3-5月子代幼龄树鼩经尾静脉注射接种KSHV病毒（5×10～7GFU/只）。在长达119 d的感染观察时间内,树鼩血液以及树鼩各组织均可检测到病毒DNA、mRNA和病毒特异性蛋白的表达,并在分离培养的淋巴细胞中观察到GFP荧光。组织病理检测显示,感染树鼩的脾脏、肺和肝脏组织中均发现淋巴细胞浸润、灶性聚集,肺泡壁增厚,肝细胞水肿和坏死现象。免疫组化检测结果表明,LANA或ORF62蛋白在脾、肺、肝和肾中表达,主要以潜伏感染LANA蛋白表达为主,表明KSHV可以在树鼩建立潜伏感染。对树鼩体内抗病毒相关炎症因子检测发现,树鼩机体内免疫排斥相关炎症因子呈现上升趋势,IFN-γ整体呈现上升趋势（增加了1000倍）,而与KSHV致病性相关IL-6和IL-8炎症因子也增加了近百倍,说明KSHV感染可以引起树鼩体内强烈的抗病毒免疫应答反应。综上所述,树鼩可以支持KSHV潜伏感染和病毒复制,为进一步建立KSHV感染的树鼩疾病模型奠定了研究基础。

关键词： CO2   biomass   carbon   tropical forest   Western Ghats  

摘要： This study aims to estimate the fixed CO2 in tree biomass in the Neyyar Wildlife Sanctuary in Western Ghats, India. The methodology consists of a GIS-based estimation of atmospheric CO2, based on the Food and Agriculture Organization (FAO) estimation method. Prior to further analyses such as satellite image classification processes, radiometric and geometric corrections were conducted to remove unwanted artefacts, such as additive effects due to atmospheric scattering, using a set of preprocessing or clean-up routines. Tree vegetation categories - dense evergreen, evergreen, dense semi-evergreen, semi-evergreen, and moist deciduous - were identified. Tree formations were also categorized based on their elevation: high elevation, medium elevation, and low elevation. Findings showed that fixed CO2 per unit area (1 ha) ranged from 356.98 t for high elevation dense evergreen to 205.24 t for low elevation semi-evergreen vegetation. Different elevation ranges in those tree formations also displayed distinct differences in the fixed CO2 per unit area. For dense evergreen formation, fixed CO(2 )was highest at high elevation, lowest at medium elevation. Evergreen and dense semi-evergreen showed higher values at low elevations compared to those at medium elevations. In semi-evergreen and moist deciduous, medium elevation trees showed higher values than those at low elevations.

关键词： Botany   Ecology   Plant Sciences   Dutch elm disease   DED   Emerald ash borer   EAB   Amur honeysuckle   American elm   Ulmus americana   Lonicera maackii   Fraxinus   secondary succession  

摘要： The secondary-growth hardwood forest of Rush Run Wildlife Area (RRWA), Preble County, Ohio was studied 54 years after an initial study was conducted in 1964. Although Dutch elm disease (DED) was likely present in the area by the late 1930s to early 1940s, American elm (Ulmus americana L.) was recorded as one of the dominant canopy species (avg. relative density = 15.1%) and subcanopy species (9.0%) in 1964. Seedlings of American elm were also noted to be abundant across RRWA. Of the 17 plots used in 1964, 10 were chosen based on the previously recorded high relative density of American elm and resurveyed. By 2018, American elm was absent from the canopy, subcanopy, and seedling layers. A secondary analysis of measurements taken in 2018 that included dead standing Fraxinus spp. showed that the current loss of ash was extensive but non-impactful upon other species. Findings oppose the previous predictions that American elm can persist indefinitely in forest stands following introduction of DED but restricted to subcanopy and smaller stature. It is possible that previous studies have not allowed adequate time after introduction of DED to accurately assess the effects on American elm.