关键词： 轮状病毒   树鼩   细胞   感染   动物模型  

摘要： 轮状病毒(Rotavirus,RV)感染是引起婴幼儿及其他幼龄哺乳动物非细菌性腹泻最重要的原因,全世界因急性腹泻入院的儿童中,约60%左右为RV感染引起,因轮状病毒每年导致的死亡病例高达80万。我国儿童RV感染率和住院率分别为28%-65%和30-50%,造成相当大的的社会负担和经济损失。目前针对轮状病毒的治疗没有有效的药物,市场上现有的疫苗在不同地区作用效果差距较大,价格昂贵且存在发生潜在感染的安全隐患,因此研发安全性可靠、高效廉价的疫苗的成为当前比较重要的项目。而动物模型不仅可以研究病毒的感染进程和致病机理,同时也可以为疫苗的研发和药物的筛选提供基础性保障。目前轮状病毒的感染动物模型主要包括乳鼠、无菌猪、猴和大鼠等,由于这些模型在亲缘关系、实验周期、解剖学特性等方面的局限性,并没有动物模型的验证和清晰阐明病毒的致病机制。近年来,树鼩由于体型小、繁殖快、饲养成本低以及解剖学特性与人相近而受到重视,并且已经初步证实可以感染轮状病毒,因此成为研究轮状病毒的比较优势的动物。首先选择G1P[8]型的WA株和从临床病人粪便中分离培养的G9P[8]的JM-103作为研究对象,将病毒接种到MA-104细胞和Vero细胞中培养,通过形态学观察、测定病毒滴度等方法,筛选WA株作为优势病毒,确定MA-104细胞为宿主细胞。再将病毒进行浓缩,并且将测定病毒滴度的TCID技术条件进行优化,与此同时,建立了轮状病毒基因检测的PCR技术,为后续的实验做好准备。接着获取树鼩的原代细胞,将树鼩原代肾细胞、小肠上皮细胞进行培养、纯化,获得处于生长期的细胞再感染病毒,通过测定细胞悬液中病毒的滴度来鉴定病毒感染体外细胞的增殖特性。最后用高滴度的轮状病毒WA株通过灌胃的方式感染树鼩,记录树鼩的体重、体温、以及粪便等级和活动情况,采集树鼩不同时间段的血液、粪便、唾液等样本,同时将严重腹泻的树鼩处死获取体内组织,再用PCR技术和WB方法检测轮状病毒的表达。通过上述方法的建立全文结果如下:1.确定了高毒力和高感染力的WA株病毒和感染之后CPE更为明显的MA-104细胞用于后续实验。同时优化PEG-6000浓缩病毒的方法,获得高毒力、高滴度的轮状病毒WA株作为后续感染实验的材料。使用TCID50测定病毒滴度,通过对比不同条件的病毒滴度,建立了病毒激活的最优条件是胰酶终浓度20ug/ml,孵育时间60min。同时根据轮状病毒WA株感染增殖特性和细胞病变效应,建立轮状病毒RT-PCR检测和验证体系。2.使用0.25%的胰蛋白酶-EDTA消化法和机械振荡联合作用,成功分离获得树鼩原代肾细胞;用胶原酶Ⅺ型和中性蛋白酶I型混合消化液成功获取小肠上皮细胞。所分离出来的树鼩原代肾细胞、小肠上皮细胞贴壁速度快,生长状态好。通过利用树鼩原代细胞与成纤维细胞对胰蛋白酶敏感度的差异及贴壁时间的不同这两种特点在传代培养过程中对细胞进行纯化,得到了不含杂质细胞的树鼩原代细胞。同时对分离的树鼩原代细胞利用CCK法测定细胞增殖曲线,检测细胞的生长曲线。轮状病毒感染树鼩原代细胞,观察不同时间的细胞病变效应,感染72h原代细胞出现脱落、变圆现象。轮状病毒感染树鼩原代细胞之后,收取细胞悬液,检测细胞悬液中病毒的滴度,验证了轮状病毒WA株可以感染树鼩原代细胞。3.轮状病毒感染树鼩的最佳方式是灌胃,灌胃不同年龄的树鼩选择不同的剂量和毒力的病毒,我们选用每只树鼩灌胃2m L的病毒滴度为1?10(TCID)轮状病毒细胞悬液;感染病毒之后的树鼩,通过生命体征、活动情况、体温、体重、腹泻以及粪便等级等现象初步断定树鼩可以感染轮状病毒WA株,并且各个指标相互佐证,呈现相近规律;通过对感染树鼩的粪便、唾液、血液中轮状病毒的检测,证实轮状病毒在树鼩体内发生复制与增殖,并不简单的只是病毒的排出。我们初步建立了轮状病毒感染树鼩的动物模型,该模型的初步研究对于轮状病毒致病机制和疫苗的研发具有重要的参考意义。

关键词： Hollow-dependent wildlife   Mechanically created hollows   Hollow-bearing trees   Artificial hollows   Nest boxes   Bat boxes  

摘要： Tree hollow scarcity is a threat to cavity-dependent vertebrate wildlife world-wide across many landscapes. Currently, only nest boxes are commonly used to mitigate or offset lost cavity-bearing trees, with a number of shortfalls reported using this technique. There is a need to trial alternative techniques to improve artificial cavity provisions. This preliminary study investigated the use of carving hollows directly into tree trunks using chainsaws. Sixteen hollows of two simple cavity types were created in a timber production forest in southeastern Australia. One cavity type comprised a basal entrance (38 mm in diameter) which provided a space above the entrance, intended for bats, and the other cavity type provided a space below a 38 mm or 76 mm entrance, intended for marsupials and birds. Five species used the hollows over a 15-month cavity monitoring period;feathertail glider (Acrobates pygmaeus) (in 75% of the hollows), brown antechinus (Antechinus stuartii) (75%), sugar glider (Petaurus breviceps) (63%), long-eared bat (Nyctophilus sp.) (50%) and white-throated tree creeper (Cormobates leucophaea) (25%). Camera monitoring revealed hollow inspection after only one day post hollow creation by white-throated tree-creepers and feathertail gliders, and nest building by white-throated treecreepers after three days. No hollow host tree failure occurred for either of the two hollow wall widths trialled over two years of monitoring tree stability. Wound-wood formed and partly enclosed the hollows' faceplates over time, improving the sturdiness of the hollow and likely resulted in hollows closely resembling natural cavities. Mechanically created tree hollows have a broad application potential across many landscapes with the prospect to overcome some of the reported drawbacks of nest boxes. More research is required to document long-term performance and effectiveness of this technique.

摘要： Internally transcribed spacer (ITS) rRNA profiling is a novel tool for detailed analysis of microbial populations at low taxonomic ranks. Here we exploited this approach to explore species-level biogeography of the Bifidobacterium genus across 291 adult mammals. These include humans and 13 other primates, domesticated animals, such as dogs, cats, cows, sheep, goats, horses and pigs, and 46 additional species. The collected profiles revealed the presence of 89 putative novel bifidobacterial taxa in addition to 45 previously described species. Remarkably, in contrast to what is currently known for many gut commensals, we did not observe host-specialization among bifidobacterial species but rather their widespread distribution across mammals. Moreover, ITS rRNA profiling of wild relatives of domesticated dogs, rabbits and pigs clearly indicates that domestication and close contact with humans have impacted on the composition of the fecal bifidobacterial population. These data were complemented by analysis of bifidobacterial communities in milk of eight mammalian families, showing that bifidobacteria represent prototypical early gut microbiota members which are inherited by newborns from their lactating mother. Thus this study highlights the role of bifidobacteria as pioneering gut colonizers of a wide range of mammals.

关键词： Biodiversity patterns   Community assembly   Environmental change   Plant-herbivore interactions   Species-energy relationship   Species turnover  

摘要： In forests, local site conditions can affect both trees and herbivores and hence site-related factors act indirectly on herbivores mediated by tree growth rates. Here, tree foliage represents a fundamental prerequisite for insect herbivore development providing energy in the form of plant tissue quality. Resource-based theories, on the other hand, assume that the synthesis of defensive compounds is a trade-off with growth and peaks at low resource availability. However, the extent to which plant tissue quality in response to site productivity is relevant in the species-energy relationship is unknown. Therefore, we aimed at a better understanding of the form and structure of the species-energy relationship in forest insects. We used census data of foliage-feeding insects along a productivity gradient of Scots pine forests defined by relative growth rates of trees (RGR). As a result, diversity monotonically increases with decreasing RGR (as a proxy for energy) during almost two decades of sampling. Herbivore assemblages become more similar with available energy as species turnover linearly decreases and proportions of sites occupied by individual species rise. The results suggest that tree growth rate influences herbivore dynamics in this system by altering the chemical composition of needles, without necessarily affecting the form in the relationship. The site-specific resource availability requires trees to adjust their allocation to synthesis of carbon-based secondary metabolites or growth, which then results in fundamental differences in herbivore dynamics at low vs. lowest RGR (regular cycles (dominance) vs. dampened cycles (evenness)). However, these differences inevitably demonstrate that species richness is not necessarily a result of more individuals and implicate that different mechanisms are involved (facilitation vs. competition/temporal heterogeneity). The resulting pattern and structure of foliage-feeding insects advance our understanding of herbivore dy

关键词： bird diversity   ecological facilitation   Macrotermes   savanna dynamics   ungulates  

摘要： Vast areas of the African savanna landscapes are characterized by tree-covered Macrotermes termite mounds embedded within a relatively open savanna matrix. In concert with termites, large herbivores are important determinants of savanna woody vegetation cover. The relative cover of woody species has considerable effects on savanna function. Despite the potentially important ecological relationships between termite mounds, woody plants, large herbivores, and birds, these associations have previously received surprisingly little attention. We experimentally studied the effects of termites and large herbivores on the avian community in Lake Mburo National Park, Uganda, where woody vegetation is essentially limited to termite mounds. Our experiment comprised of four treatments in nine replicates;unfenced termite mounds, fenced mounds (excluding large mammals), unfenced adjacent savanna, and fenced savanna. We recorded species identity, abundance, and behavior of all birds observed on these plots over a two-month period, from late dry until wet season. Birds used termite mounds almost exclusively, with only 3.5% of observations occurring in the treeless intermound savanna matrix. Mean abundance and species richness of birds doubled on fenced (large herbivores excluded) compared to unfenced mounds. Feeding behavior increased when large mammals were excluded from mounds, both in absolute number of observed individuals, and relative to other behaviors. This study documents the fundamental positive impact of Macrotermes termites on bird abundance and diversity in an African savanna. Birds play crucial functional roles in savanna ecosystems, for example, by dispersing fruits or regulating herbivorous insect populations. Thus, the role of birds in savanna dynamics depends on the distribution and abundance of termite mounds.

关键词： 野生动物   管护责任   国有林场   护林员   海峰   城口县  

摘要： 【我的敝赘】2017年10月13日，城口县国有林场护林员陶海峰按例巡视其管护责任片区。茂密林间，陶海峰缓步穿梭，不时四处张望，仔细查看林中各个角落，以防疏漏可能存在的火睛。二十余年如一日，陶海峰在巡山护林过程中始终保持高度警惕。

关键词： Pan troglodytes   Meat eating   Early hominins   Ugalla   Predation   Faunivory  

摘要： There is broad consensus among paleoanthropologists that meat-eating played a key role in the evolution of Homo, but the details of where, when, and why are hotly debated. It has been argued that increased faunivory was causally connected with hominin adaptation to open, savanna habitats. If savanna-dwelling chimpanzees eat meat more frequently than do forest chimpanzees, it would support the notion that open, dry, seasonal habitats promote hunting or scavenging by hominoids. Here we present observational and fecal analysis data on vertebrate consumption from several localities within the dry, open Ugalla region of Tanzania. Combining these with published fecal analyses, we summarize chimpanzee vertebrate consumption rates, showing quantitatively that savanna chimpanzee populations do not differ significantly from forest populations. Compared with forest populations, savanna chimpanzees consume smaller vertebrates that are less likely to be shared, and they do so more seasonally. Analyses of chimpanzee hunting that focus exclusively on capture of forest monkeys are thus difficult to apply to chimpanzee faunivory in open-country habitats and may be misleading when used to model early hominin behavior. These findings bear on discussions of why chimpanzees hunt and suggest that increases in hominin faunivory were related to differences between hominins and chimpanzees and/or differences between modern and Pliocene savanna woodland environments. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： BEF-China   biodiversity   canopy layers   community composition   ecosystem functioning   forest succession   plant-herbivore interactions   trophic groups  

摘要： The high tree diversity of subtropical forests is linked to the biodiversity of other trophic levels. Disentangling the effects of tree species richness and composition, forest age, and stand structure on higher trophic levels in a forest landscape is important for understanding the factors that promote biodiversity and ecosystem functioning. Using a plot network spanning gradients of tree diversity and secondary succession in subtropical forest, we tested the effects of tree community characteristics (species richness and composition) and forest succession (stand age) on arthropod community characteristics (morphotype diversity, abundance and composition) of four arthropod functional groups. We posit that these gradients differentially affect the arthropod functional groups, which mediates the diversity, composition, and abundance of arthropods in subtropical forests. We found that herbivore richness was positively related to tree species richness. Furthermore, the composition of herbivore communities was associated with tree species composition. In contrast, detritivore richness and composition was associated with stand age instead of tree diversity. Predator and pollinator richness and abundance were not strongly related to either gradient, although positive trends with tree species richness were found for predators. The weaker effect of tree diversity on predators suggests a cascading diversity effect from trees to herbivores to predators. Our results suggest that arthropod diversity in a subtropical forest reflects the net outcome of complex interactions among variables associated with tree diversity and stand age. Despite this complexity, there are clear linkages between the overall richness and composition of tree and arthropod communities, in particular herbivores, demonstrating that these trophic levels directly impact each other.

关键词： carbon dynamics   mesocosm   non-additive effects   old growth   Panama   pioneer   soil fauna  

摘要： Disturbance can alter tree species and functional diversity in tropical forests, which in turn could affect carbon and nutrient cycling via the decomposition of plant litter. However, the influence of tropical tree diversity on forest floor organisms and the processes they mediate are far from clear. We investigated the influence of different litter mixtures on arthropod communities and decomposition processes in a 60-year-old lowland tropical forest in Panama, Central America. We used litter mixtures representing pioneer and old growth tree species in experimental mesocosms to assess the links between litter types, decomposition rates, and litter arthropod communities. Overall, pioneer species litter decomposed most rapidly and old growth species litter decomposed the slowest but there were clear nonadditive effects of litter mixtures containing both functional groups. We observed distinct arthropod communities in different litter mixtures at 6 mo, with greater arthropod diversity and abundance in litter from old growth forest species. By comparing the decay of different litter mixtures in mesocosms and conventional litterbags, we demonstrated that our mesocosms represent an effective approach to link studies of litter decomposition and arthropod communities. Our results indicate that changes in the functional diversity of litter could have wider implications for arthropod communities and ecosystem functioning in tropical forests. Abstract in Spanish is available with online material.

关键词： Animal conservation   Wildlife monitoring   Object detection   Active learning   Crowd-sourcing data   Unmanned aerial vehicles   Very high resolution  

摘要： Unmanned aerial vehicles (UAVs) offer new opportunities for wildlife monitoring, with several advantages over traditional field-based methods. They have readily been used to count birds, marine mammals and large herbivores in different environments, tasks which are routinely performed through manual counting in large collections of images. In this paper, we propose a semi-automatic system able to detect large mammals in semi-arid Savanna. It relies on an animal -detection system based on machine learning, trained with crowd-sourced annotations provided by volunteers who manually interpreted sub-decimeter resolution color images. The system achieves a high recall rate and a human operator can then eliminate false detections with limited effort. Our system provides good perspectives for the development of data-driven management practices in wildlife conservation. It shows that the detection of large mammals in semi-arid Savanna can be approached by processing data provided by standard RGB cameras mounted on affordable fixed wings UAVs.