地表火对红花尔基沙地樟子松种群空间分布格局的影响

利用全林木定位的方法, 对地表火干扰1年后的樟子松(Pinus sylvestris L. var. mongolica Litv.)林进行调查, 并通过假设检验和成对相关函数对其林火及林分结构特征和空间格局进行分析。结果表明, 林火强度相似的同一场地表火干扰下, 不同林分的密度均大大降低, 胸高断面积仅略有下降, 林分结构特征则有趋同的态势。不同林分的空间格局也有相似的变化趋势, 烧死木均表现为显著的双尺度聚集分布及显著的正相关, 活立木也表现出显著的正相关; 地表火干扰前后, 樟子松林的空间格局均为显著的聚集分布, 但地表火干扰后其聚集分布的尺度范围变小; 存活林木中, 大树和幼树则呈现出相互独立或略微排斥的关系。显然, 地表火驱动下, 不同樟子松林的空间格局呈现出相似的变化趋势, 并推动其向着成熟林方向演替, 这对天然樟子松林的资源保护和经营管理有着重要意义。     

鄂尔多斯高原北缘水分梯度下天然植被分布格局初探

以鄂尔多斯高原杭锦旗北部独贵塔拉镇的过渡带为研究对象,通过样线调查,研究了水分梯度下天然植被的空间分布规律.TWINSPAN的分类结果表明,群落以中生和旱生为主,一些耐盐的植物散布其中;相邻样方间相似性指数的变化反映了不同类型群落在研究区内的镶嵌分布,从而形成了该区域内群落的多样性和复杂性.对植被样方与地形地貌因子的CCA排序结果显示,植被群落空间格局的形成更多地取决于区域内的水分变化梯度.在本文的研究尺度上,这种水分变化梯度主要由微地形地貌的变化来决定,而不是由与黄河的距离因子来决定.因此,在本区域的土地开发利用过程中,应充分考虑目前已经形成的相对稳定的地形地貌单元特点,在缺乏完善的风沙防护措施和排水除盐措施的情况下,不宜采取大规模平整土地进行综合开发.     

Chemotype of tansy (Tanacetum vulgare L.) determines aphid genotype and its associated predator system

Field assessments and genetic analyses on tansy aphid, Metopeurum fuscoviride Stroyan were made aiming to investigate whether a specialist aphid species and its associated predator density differ between chemotypes of the plant host, tansy, and whether the essential oil composition of the plant host determines the genetic differences observed between colonies of M. fuscoviride inhabiting these different chemotypes. Tansy plants were defined after volatile extractions as Camphor Pure and Borneol Pure, respectively, with hybrid chemotypes defined as Camphor Hybrid, Borneol Hybrid, and Thujone Hybrid, respectively. Ladybird beetles, Coccinella septempunctata (L.), clearly dominated Pure Camphor plants, whereas significantly higher numbers of the nursery web spider, Pisaura mirabilis (Clerck), were detected on Borneol Pure and Borneol Hybrid plants. Genetic analyses using five polymorphic microsatellite markers revealed that higher genetic similarity existed between M. fuscoviride aphids from Borneol Pure and Borneol Hybrid plants and between Camphor Pure and Camphor Hybrid plants, respectively, whereas a lower level of genetic similarity was seen between these aphids from Thujone Hybrid plants. Accordingly, it is possible that host plant‐adapted species can create much context‐dependency in the nature and strength of predation effects, which may in turn alter costs and benefits of host plant chemical differentiations, or even the prey genotype variations. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114 , 709–719.     

Identification and optimization of a novel series of [2.2.1]-oxabicyclo imide-based androgen receptor antagonists

A novel series of [2.2.1]-oxabicyclo imide-based compounds were identified as potent antagonists of the androgen receptor. Molecular modeling and iterative drug design were applied to optimize this series. The lead compound [3aS-(3aalpha,4beta,5beta,7beta,7aalpha)]-4-(octahydro-5-hydroxy-4,7-dimethyl-1,3-dioxo-4,7-epoxy-2H-isoindol-2-yl)-2-iodobenzonitrile was shown to have potent in vivo efficacy after oral dosing in the CWR22 human prostate tumor xenograph model.     

亚热带森林乔木树种DNA条形码研究——以哀牢山自然保护区为例

作为新一代植物志iFlora的重要组成部分,DNA条形码已经成为物种鉴定中重要且有效的方法。本研究以亚热带森林的乔木树种为研究对象,开展了DNA条形码的尝试性工作。为评估DNA条形码对鉴定亚热带森林树种的有效性,收集并研究了来自哀牢山自然保护区内5l科111属中204个树种的525个乔木个体。结果显示,所选4个DNA片段（rbcL,matK,trnH-psbA和ITS）的PCR扩增成功率都超过90％;测序成功率rbcL和matK最高,分别为90．7％和90．5％,trnH-psbA次之（83．6％）,ITS最低（73．5％）,表明4个片段在亚热带森林乔木中都具有较好的通用性。应用BLAST与NJ Tree两种方法,对物种和属水平的鉴别成功率进行统计,发现单片段中ITS最高,分别为68．4％-81．3％和99．0％～100％,核心条码rkL和matK组合的成功率是52．8％～60．2％和86．7％～90．5％,再与补充条码trnH-psbA和ITS联合,可以成功鉴别74．7％～79．6％哀牢山自然保护区亚热带森林中的乔木物种。由于ITS片段在亚热带森林部分重要树种类群（樟科和壳斗科等）中的测序成功率较差,所以对这些植物类群采用trnH-psbA作为DNA条形码是一个更好的选择。     

Demographic history of the Tibetan antelope Pantholops hodgsoni(chiru)

The Tibetan antelope(chiru,Pantholops hodgsoni),a heavily poached species and symbol of the QinghaiTibetan Plateau(QTP),is noted worldwide for its special calving migration.This species originated in the early Quaternary and it is interesting to know how the following climatic oscillations affected its demographic dynamics in the climate-sensitive QTP.In this study,we analyzed the mitochondrial D-loop region from 312 individuals sampled in all of the six major populations.We found high rates of gene flow and little genetic differentiation between populations,suggesting that the calving migration may have homogenized the genetic pool of this species.Both mismatch distribution analyses and coalescent simulations suggested that this species experienced a demographic expansion approximately 600-200 Kyt following the retreat of the large glaciers developed in the QTP at 800-600 Kyr,rather than at the end of the last glacial age,as previously suggested based on a limited sample size.In addition,we found evidence of a chiru population decrease probably related to the human settings at the QTP during the middle Holocene.     

干旱与盐胁迫对花生根际土壤细菌群落结构和花生产量的影响

以花生品种花育25号为试验材料,采用盆栽试验研究了开花期干旱和盐分胁迫对花生生长发育和荚果产量的影响,并运用高通量测序技术分析干旱、盐胁迫及旱盐双重胁迫下,花生根际土壤细菌群落结构的变化特征。结果表明: 不同胁迫处理花生根际土壤细菌群落均以变形菌门、放线菌门、Saccharibacteria、绿弯菌门、蓝藻菌门和酸杆菌门为主。干旱、盐胁迫及旱盐双重胁迫均不同程度降低了变形菌门和放线菌门的相对丰度,但显著提高了蓝藻菌门的含量,且旱盐双重胁迫较其单一胁迫引起的根际蓝藻菌门丰度变化更显著。土壤细菌功能预测分析显示,信号转导机制、防御机制及翻译后修饰、蛋白质周转和分子伴侣等相关功能在旱盐双重胁迫的细菌中活性更强,可能对花生生长及胁迫应答具有重要影响。统计学分析显示,开花期干旱、盐胁迫和旱盐双重胁迫严重影响花生生长发育,并显著降低产量。研究结果可为通过改良土壤微生物环境来提高植物胁迫耐受性提供参考。     

Sex-dependent antioxidant enzyme activities and lipid peroxidation in ageing mouse brain

We investigated whether oxidant status and antioxidant enzyme activities during ageing of mouse brain are regulated in sex-dependent manner. In the homogenate from the brain of 1, 4, 10 and 18 months old male and female CBA mice, lipid peroxidation (LPO), total superoxide dismutase (tSOD), catalase (CAT) and glutathione peroxidase (Gpx) were determined. LPO was age- and sex-related, favoring males over females throughout the lifespan with the peak in both sexes at 10 months of age. Throughout ageing, no difference in tSOD activity between male and female brains was observed, except in immature 1 month old mice. Gender-related difference in Gpx activity was observed, with higher level in females comparing to males, reaching statistical significance in senescent (18 months old) animals. CAT activity was drastically changed with ageing in both the male and female brain. We found different age associated trends in CAT activity in males and females: decreased with age in males and increased with age in females. Taken together, the present findings indicate that brains of female mice have lower oxidant and higher antioxidant capacity mostly related to CAT and to a lesser extent to Gpx activity.     

广义估计方程在CT显示方法研究数据分析中的应用

目的:探讨广义估计方程在CT显示方法研究中的应用.方法:采用SAS软件的GENMOD过程,应用广义估计方程方法分析CT显示方法研究实例.结果:给出了广义估计方程SAS程序,并对参数估计和两两比较结果进行解释.结论:广义估计方程能有效的分析CT显示方法研究中反应变量为两分类或多分类的非独立数据.     

The SAM kinase pathway: An integrated circuit for stress signaling in plants

Mitogen-activated protein (MAP) kinases are universal transducers of extracellular signals in all eukaryotes. Multiple MAPK pathways exist in each organism that are differentially activated by a variety of stimuli including chemical as well as physical factors. We have characterized the stress-activated MAP kinase (SAMK) pathway in plants that is involved in mediating touch, drought, cold, and wounding. The SAMK pathway is activated by a posttranslational mechanism, but inactivation requires de novo expression of gene(s). One of these genes isMP2C encoding a protein phosphatase type 2C that is able to inactivate the SAMK pathway.MP2C expression itself is regulated by the SAMK pathway and constitutes a negative feedback mechanism for resetting the pathway. The extended abstract of a paper presented at the 13th International Symposium in Conjugation with Award of the International Prize for Biology “Frontier of Plant Biology”