Five New Guaiane Sesquiterpenes from the Endophytic Fungus Xylaria sp. YM 311647 of Azadirachta indica

Five new guaiane sesquiterpenes, 1 – 5 , were isolated from the culture broth of the endophytic fungus Xylaria sp. YM 311647, isolated from Azadirachta indica A. Juss . The structures of these compounds were elucidated on the basis of spectroscopic analyses, and their inhibitory activities against five pathogenic fungi were evaluated. All guaiane sesquiterpenes showed moderate or weak antifungal activities in a broth microdilution assay.     

雪豹（Uncia uncia）研究的文献计量评价

通过对1950—2010年SCI收录和1989—2010年CSCD收录的雪豹(Uncia uncia)研究文献分析,从年度文献数量变化、国家/地区分布、主要研究机构、期刊分布、发表文献作者、基金资助机构、刊载文献类型、学科类别和语种分布9个方面,对雪豹研究文献的分布规律和研究现状进行了统计分析。结果表明:在SCI上发表雪豹研究论文的国家排名依次是美(50.6%)、英(16.5%)、印度(12.5%)和中国(5.6%);在文献量机构排名方面,国际雪豹基金会和英国爱丁堡大学并列第一,中国科学院排名第五;中国的主要合作国家中包括了美、英和中亚国家(吉尔吉斯斯坦、蒙古)。无论是分布范围还是数量,中国雪豹资源都居于世界第一,而研究却不相匹配,国内在这方面还仍需努力。     

中国野生动物调查存在的问题与改进建议

一百余年前,人类就开始了相对系统的野生动物调查。目前已经建立了成熟的方法体系,并制定了相应的调查规范。最近几十年来,我国科研人员进行了大量的野生动物调查。但是,当前我国的野外调查规范还不够细致,调查者在调查时缺乏必要的约束,导致调查数据不规范、不可靠,很多重要信息缺失。突出问题有：样线信息不全,只有起点和终点的经纬度,没有自动记录的详细样线信息（如每秒记录一次的连续点位信息,含经纬度和时间）;动物位点信息缺乏可信度指标（如距观测者的距离）;调查时间不合理;调查地点的空间取样不均衡;记录的标准化不够（如每个观测点的观测时长不确定）等等。对此,我们参考国际通用的调查规范,提出了一些简单易行的调查要点,以便提高野外调查数据的质量。另外,我们提倡野外记录的无纸化,充分利用现有的手机应用软件（APP）和模型工具提高野外记录以及后期数据处理的效率。最后,我们提议建立固定的中国生物多样性监测样线体系,以便消除每年调查时空间取样的不确定性,更好地量化野生动物的时间动态,为野生动物的保护和管理提供依据。     

下辽河平原降雨中氮素的动态变化

为了了解降雨中氮对农田生态系统的影响,分析了2004-2006年下辽河平原连续3年定位收集的降雨观测资料与历史资料.结果表明:降雨中氮输入量季节变化显著,夏季最高,这主要与降雨量及空气中NH4 -N浓度变化有关;降雨中DON量与NO3--N含量相当,均接近24%,是雨水中氮的重要组分;与1985年相比,近3年降雨输入到该地区农田生态系统的年氮通量已有较大提高,降雨较多的2005年输入的无机氮量更是20年前的2倍以上;2004-2006年随降雨输入农田生态系统的氮平均占可利用肥料氮的28.3%,对农田生态系统有着重要影响.     

Inhibitory CD161 receptor identified in glioma-infiltrating T cells by single-cell analysis

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Varying Patterns on Varying Scales: A Metacommunity Analysis of Nematodes in European Lakes

Ecological community patterns are often extremely complex and the factors with the greatest influence on community structure have yet to be identified. In this study we used the elements of metacommunity structure (EMS) framework to characterize the metacommunities of freshwater nematodes in 16 European lakes at four geographical scales (radius ranging from 80 m to 360 km). The site characteristics associated with site scores indicative of the structuring gradient were identified using Spearman rank correlations. The metacommunities of the 174 nematode species included in this analysis mostly had a coherent pattern. The degree of turnover increased with increasing scale. Ordination scores correlated with geographical variables on the larger scales and with the trophic state index on a regional scale. The association of the structuring gradient with spatial variables and the scale-dependent increase in turnover showed that nematode dispersal was limited. The different metacommunity patterns identified at the increasing geographical scales suggested different, scale-related mechanisms of species distribution, with species sorting dominating on smaller and mass effects on larger geographical scales.     

A Dual Role for Corneal Dendritic Cells in Herpes Simplex Keratitis: Local Suppression of Corneal Damage and Promotion of Systemic Viral Dissemination

The cornea is the shield to the foreign world and thus, a primary site for peripheral infections. However, transparency and vision are incompatible with inflammation and scarring that may result from infections. Thus, the cornea is required to perform a delicate balance between fighting infections and preserving vision. To date, little is known about the specific role of antigen-presenting cells in viral keratitis. In this study, utilizing an established murine model of primary acute herpes simplex virus (HSV)-1 keratitis, we demonstrate that primary HSV keratitis results in increased conventional dendritic cells (cDCs) and macrophages within 24 hours after infection. Local depletion of cDCs in CD11c-DTR mice by subconjuntival diphtheria toxin injections, led to increased viral proliferation, and influx of inflammatory cells, resulting in increased scarring and clinical keratitis. In addition, while HSV infection resulted in significant corneal nerve destruction, local depletion of cDCs resulted in a much more severe loss of corneal nerves. Further, local cDC depletion resulted in decreased corneal nerve infection, and subsequently decreased and delayed systemic viral transmission in the trigeminal ganglion and draining lymph node, resulting in decreased mortality of mice. In contrast, sham depletion or depletion of macrophages through local injection of clodronate liposomes had neither a significant impact on the cornea, nor an effect on systemic viral transmission. In conclusion, we demonstrate that corneal cDCs may play a primary role in local corneal defense during viral keratitis and preserve vision, at the cost of inducing systemic viral dissemination, leading to increased mortality.     

The xylA promoter of Bacillus megaterium mediates constitutive gene expression in Escherichia coli

In the present study, we demonstrate that the Escherichia coli–Bacillus megaterium shuttle vector pHIS1522 can be used as a versatile expression vector. Recombinant genes under the control of the xylA promoter are constitutively expressed at a high level in E. coli strains, whereas their expression is strongly induced by the addition of xylose in B. megaterium. The utilization of D ‐xylose is known to be dependent on the xylAB genes in a number of bacteria. For B. megaterium a XylA‐based expression system was established that allows tightly regulated and highly efficient heterologous gene expression. The open reading frame (ORF) of the fluorescent protein turboRFP was cloned under the control of the xylA promoter of B. megaterium in the shuttle vector pHIS1522. Unexpectedly, tRFP expression was not only observed in B. megaterium, but also in E. coli. Based on fluorescence measurements and Western blot analysis, expression was comparable or slightly higher compared with the commonly used pET vectors. Therefore, pHIS1522 can be used as a versatile expression vector in both, B. megaterium and E. coli.