高寒草甸不同斑块草地土壤微生物多样性特征研究

本文以矮嵩草(Kobresia humilis)高寒草甸及退化后形成的不同退化斑块群落类型草地土壤为研究对象,利用Illumina MiSeq高通量测序技术分析了不同斑块草地土壤中微生物群落结构组成和多样性变化特点,并分析了土壤微生物与土壤养分之间的相关性.结果表明:以矮嵩草为优势植物的高寒草甸群落变为以细叶亚菊(A ...     

改进型中草药921合剂结合α-酮戊二酸对断奶大鼠肠道免疫的影响

研究了改进型中草药921合剂结合α 酮戊二酸(α ketoglutarate,AKG)作为饲料添加剂对体重为40.0±5g18日龄断奶大鼠小肠上皮淋巴集结数量、面积和十二指肠肠液中IgA的含量进行了测定。纯系断奶大白鼠被随机分为对照组、中草药组和中草药加AKG组,每组10只,分别饲喂1～2周,然后对上述内容进行研究。结果为:饲喂1周后,对照组、中草药组和中草药加AKG组小肠上皮淋巴结数量分别为16.4±1.23,14.2±0.63,15.1±0.68个(P>0.05);3组间十二指肠肠液中IgA含量分别为0.844±0.020,0.921±0.039,1.236±0.131g·L-1(P<0.01)。饲喂2周后对照组、中草药组和中草药加AKG组小肠上皮淋巴结数量分别为15.6±0.50,16.4±0.94,15.6±0.99个(P>0.05);3组间前段肠上皮淋巴集结面积分别为27.7±2.02,44.8±4.34,42.4±1.93mm2(P<0.01);中段分别为28.1±1.10,40.5±5.68,55.4±2.28mm2(P<0.01);后段分别为37.6±4.57,63.6±4.94,59.0±5.35mm2(P<0.01);3组间十二指肠肠液中IgA含量分别为0.256±0.015,0.493±0.030,0.601±0.047g·L-1(P<0.01)。中草药组和中草药加AKG组十二指肠IgA含量均显著高于对照组。研究表明:中草药结合AKG可以通过增加小肠上皮淋巴集结面积,增加肠道IgA的分泌,从而快速有效的改善肠道的生长和发育及黏膜     

Effects of oral supplementation with bovine colostrum on the immune system of weaned piglets

The aim of this study was to evaluate the influence of bovine colostrum supplementation on the immune system of weaned piglets in a context of a full ban of in-feed antibiotics. After weaning at 21 days, 24 outbred piglets were fed with a diet supplemented daily for three weeks with 0, 1 or 5 g of colostrum. Feed intake, growth performance, haematological parameters, and serum and local anti-colostrum immunoglobulin levels were examined. Lymphocytes from the blood, spleen, and gut-associated lymphoid were analysed for phenotype as well as for their ability to produce cytokines. The stimulation index (SI) of mononuclear cells from different organs was obtained after colostral or mitogenic stimulation. Feed intake, growth, and haematological parameters were not significantly affected by colostrum. Total serum IgA levels were increased after colostrum supplementation, with a transient decrease in total IgG. Local anti-colostrum immunization was observed in colostrum-fed piglets. The CD21+/CD3+ cells populations of the ileal Peyer's patch (iPP) were markedly affected. The SI of lymphocyte populations changed significantly whereas, naive blood lymphocytes were not stimulated in vitro in the presence of bovine colostrum, suggesting local anti-colostrum immunization and an absence of direct mitogenic effects of the colostrum. Both Th1 and Th2 cytokine production was present in the different organs of colostrum-fed piglets. Bovine colostrum especially stimulated iPP cells.     

Site-Specific Weed Control in Maize,Sugar Beet,Winter Wheat,and Winter Barley

A four-year study of site-specific weed control is presented in this paper. Weed seedling distribution was sampled and mapped prior to and after post-emergence herbicide application in four fields planted with maize, sugar beets, winter wheat and winter barley, rotating on one site. Herbicides and other weed control strategies were applied site-specifically according to the spatial variation of weed populations. Different decision algorithms were used for chemical weed control methods in each crop. A weed treatment map was created to direct location and dosage of herbicide application. The sprayer was coupled with a differential Global Positioning System (DGPS). The solenoid valves of the sprayer were opened automatically when the tractor entered a weed patch characterized in the weed treatment map. For site specific herbicide application, a patch sprayer was developed that allowed variable rate application and the selective control of each section of the spray boom.     

A tale of urban forest patch governance in four eastern US cities

Urban forests are important components of societal interactions with nature. We focused on urban forest patches, a distinct and underexplored subset of the urban forest that spans land uses and ownerships, and requires silvicultural practices to address their unique biophysical characteristics and management regimes. Our goal was to elucidate multi-scalar urban forest patch governance arrangements as they translated to on-the-ground management in four urban areas (Chicago, New York City, Philadelphia, and Baltimore) within the eastern United States. A transdisciplinary knowledge co-production framework was used to guide identification of the prominent management challenge or dilemma motivating change to forest patch management in each location, and to describe the dynamic interplay of decision-making and governance processes across locations as they advanced toward desired forest conditions. A common management goal existed across all four locations: multi-age, structurally complex forests dominated by regionally native species. Ecological and social concerns affected by local context and city capacity served as starting points prompting management action and new collaborations. Disparate governance arrangements including top-down municipal resources, regional conservation facilitated by landowners, and grass-roots community-driven stewardship led to diverse support-building processes and innovative strategies that served as forces initiating and shaping new management actions. Science and iterative learning and adaptation influenced change in all locations, reinforcing new management arrangements and practices. Among the four study areas, the earliest management of urban forest patches started in the 1980 s, historically lacking embeddedness in urban forest management more broadly, and experiencing challenges with integration into existing governance infrastructure. Ultimately, new management and governance approaches to urban forest patches in all four study areas have evolved uniquely and organically, driven by place-based historical legacies and ongoing socio-ecological feedbacks. The generalization of findings for broader urban forest management guidelines, such as for trees and park, would lead to misguided outcomes.     

土地利用数据综合中图斑多边形决策推理

针对土地利用数据综合中图斑的化简处理,将智能体技术引入到图斑的综合处理过程中,建立了顾及多种条件的图斑重要性判断的决策机制,将可操作的几何、语义控制指标融入到推理中,实现了从图斑重要性判断到尺度变换算子选择的自动化过程,最后通过实际生产进行检验,结果显示该过程能够大幅度地提高生产效率,并能够很好地维护土地利用数据的面积平衡性以及全覆盖、无重叠、无缝隙的特征.该研究可为多比例尺国土资源数据库提供技术支持.     

Medicago truncatula as a model host for studying legume infecting Rhizoctonia solani and identification of a locus affecting resistance to root canker

The broad‐host‐range necrotizing fungal pathogen Rhizoctonia solani is responsible for economically significant diseases to crops as diverse as wheat, maize, barley, canola, sugar beet, potato, soyabean, bean, lupin and alfalfa. Germplasm screens in many of the crop hosts have not identified strong genetic resistance which, together with the lack of effective control, mean the pathogen remains a substantial problem for agriculture in many parts of the world. Following the establishment of a robust inoculation assay, a germplasm collection of the model legume Medicago truncatula was screened with various legume‐infecting isolates of R. solani. While some significant differences in susceptibility/resistance were detected between some lines, in the majority of cases M. truncatula was susceptible to R. solani. Comparison of a legume‐ and cereal‐infecting AG8 isolate with a legume‐specific AG11 isolate revealed no difference in pathogenicity between the two isolates when infecting M. truncatula. The most significant differences in susceptibility occurred with an AG6 isolate, which caused root canker. This included significant differences between the moderate resistance of the M. truncatula reference genotype A17 and the high susceptibility of line A20. The analysis of a recombinant inbred line population derived from A17 and A20 revealed a single locus contributing to the resistance in A17. Interestingly, the locus only affected the development of post‐emergent (late) symptoms, such as necrosis of cotyledons at 11 days after inoculation and root‐ and above‐ground‐weights, but not pre‐emergent seedling damping off. These findings pave the way for further studies to dissect the genetic and molecular mechanisms of resistance.     

茶叶挥发物对鞍形花蟹蛛觅食行为的影响

为了探明茶叶挥发物在鞍形花蟹蛛(Xysticus ephippiatus Simon)搜寻猎物——茶尺蠖(Ectropis obliqua Prout)过程中的作用,采用固相微萃取气相色谱质谱联用技术研究了茶尺蠖取食对茶树叶片挥发物释放的影响,并通过蜘蛛行为观测平台研究了蟹蛛在不同味源侧(觅食斑块)的活动行为。结果表明:对照叶片没有释放出挥发物,经茶尺蠖幼虫取食后的叶片能释放31种挥发物,其中有12种绿叶挥发物、9种萜类及其衍生物、4种芳香族挥发物和6种未知化合物。行为观测表明,雌、雄蟹蛛进入处理味源侧(茶尺蠖取食后的茶树叶片)和对照味源侧(未损伤茶树叶片)的初次选择均不存在差别(P>0.05),雌蛛进入处理味源侧和对照味源侧的频次分别为3.37±0.18和3.43±0.15,二者无明显区别(P>0.05);雄蛛进入两侧的频次分别为3.86±0.21和3.66±0.20,也无明显区别(P>0.05);雌蛛在处理味源侧和对照味源侧的停留时间分别为(922.57±19.59)s和(818.89±29.63)s,有极显著差异(P<0.01),雄蛛在两侧的停留时间分别为(937.97±18.05)s和(814.83±18.97)s,也有极显著差异(P<0.01),表明雌蛛、雄蛛在处理侧的停留时间明显延长。这说明,猎物取食诱导改变了茶树叶片挥发物的释放,而鞍形花蟹蛛能感知挥发物的变化并由此调整在不同觅食斑块中的停留时间。另外,本文还讨论了挥发物在蟹蛛搜寻猎物过程中的生态学意义。     

��-Conotoxin GVIA Mimetics that Bind and Inhibit Neuronal Cav2.2 Ion Channels

The neuronal voltage-gated N-type calcium channel (Ca_v2.2) is a validated target for the treatment of neuropathic pain. A small library of anthranilamide-derived ω-Conotoxin GVIA mimetics bearing the diphenylmethylpiperazine moiety were prepared and tested using three experimental measures of calcium channel blockade. These consisted of a ¹²⁵I-ω-conotoxin GVIA displacement assay, a fluorescence-based calcium response assay with SH-SY5Y neuroblastoma cells, and a whole-cell patch clamp electrophysiology assay with HEK293 cells stably expressing human Ca_v2.2 channels. A subset of compounds were active in all three assays. This is the first time that compounds designed to be mimics of ω-conotoxin GVIA and found to be active in the ¹²⁵I-ω-conotoxin GVIA displacement assay have also been shown to block functional ion channels in a dose-dependent manner.