Solar radiation and functional traits explain the decline of forest primary productivity along a tropical elevation gradient

One of the major challenges in ecology is to understand how ecosystems respond to changes in environmental conditions, and how taxonomic and functional diversity mediate these changes. In this study, we use a trait‐spectra and individual‐based model, to analyse variation in forest primary productivity along a 3.3 km elevation gradient in the Amazon‐Andes. The model accurately predicted the magnitude and trends in forest productivity with elevation, with solar radiation and plant functional traits (leaf dry mass per area, leaf nitrogen and phosphorus concentration, and wood density) collectively accounting for productivity variation. Remarkably, explicit representation of temperature variation with elevation was not required to achieve accurate predictions of forest productivity, as trait variation driven by species turnover appears to capture the effect of temperature. Our semi‐mechanistic model suggests that spatial variation in traits can potentially be used to estimate spatial variation in productivity at the landscape scale.     

电针诱导心肌缺血大鼠延髓头端腹外侧区nNOS和iNOS差异表达

许多研究表明,延髓头端腹外侧区(rostral ventrolateml medulla,RVLM)的NO/NOS系统参与心血管活动的中枢调节.本实验以结扎Wistar大鼠左冠状动脉前降支法建立急性心肌缺血(acute myocardial ischemia,AMI)动物模型,观察针刺"内关"穴改善AMI大鼠的心功能作用,同时检测大鼠RVLM区神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)和诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达的变化,进而探讨针刺治疗AMI的中枢机制.实验观察显示,AMI大鼠心功能各项指标减弱,伴随外周血去甲肾上腺素(norepinephrine,NE)和脑钠肽(brain natriuretic peptide,BNP)水平显著升高,同时RVLM区nNOS阳性神经元数和nNOS mRNA表达升高,而iNOS水平则降低.针刺"内关"穴(Pe 6)(每天30 min,连续5天)改善心功能,降低AMI大鼠血清中NE和BNP的水平,同时升高iNOS并降低nNOS在RVLM的表达.以上结果提示,针刺治疗心肌缺血的同时可以调节iNOS/NO和nNOS/NO在RVLM的变化,这可能与针刺通过调节RVLM区的NO含量进而降低交感传出,从而改善AMI大鼠的心功能有关.     

Invasive cane toads are unique in shape but overlap in ecological niche compared to Australian native frogs

Invasive species are an important issue worldwide but predicting invasiveness, and the underlying mechanisms that cause it, is difficult. There are several primary hypotheses to explain invasion success. Two main hypothesis based on niche spaces stand out as alternative, although not exclusive. The empty niche hypothesis states that invaders occupy a vacant niche space in the recipient community, and the niche competition hypothesis states that invaders overlap with native species in niche space. Studies on trait similarity/dissimilarity between the invader and native species can provide information on their niche overlap. Here, we use the highly invasive and well‐studied cane toad (Rhinella marina) to test these two hypotheses in Australia, and assess its degree of overlap with native species in several niche dimensions. We compare extensive morphological and environmental data of this successful invader to 235 species (97%) of native Australian frogs. Our study is the first to document the significant morphological differences between the invasive cane toad and a continent‐wide frog radiation: despite significant environmental overlap, cane toads were distinct in body size and shape from most Australian frog species, suggesting that in addition to their previously documented phenotypic plasticity and wide environmental and trophic niche breadth, their unique shape also may have contributed to their success as an invasive species in Australia. Thus, the invasive success of cane toads in Australia may be explained through them successfully colonizing an empty niche among Australian anurans. Our results support that the cane toad's distinct morphology may have played a unique role in the invasiveness of this species in Australia, which coupled with a broad environmental niche breadth, would have boosted their ability to expand their distribution across Australia. We also propose RLLR (Relative limb length ratio) as a potentially useful measure of identifying morphological niche uniqueness and a potential measure of invasiveness potential in anuran amphibians.     

人红细胞生成素单克隆抗体的制备、鉴定及应用研究

用rhEPo作为抗原,免疫BALB／c小鼠,取其脾细胞与x63Ag8．653小鼠骨髓瘤细胞融合,再碱性PAGE方法进一步分离并纯化的rhEpo,包被Pvc板,对杂交瘤用ELlSA方法进行筛选,获得两株稳定分泌抗hEPO单抗的杂交瘤细胞株。经鉴定分别属于IgG1、IgG2b,轻链均为k链,Kd分别为5．53×10^-10mol／L和1．34×1O^-10mol／L．用western blot方法证明两者对hEPO具有高度韵专一性．能特异地识别rhEPO和尿源hEPO。所制备单抗可作为亲和层析的配体,用于再生障碍性贫血病人尿中EPO及哺乳类工程细胞所表达的hEPO的分离、纯化,并可用于hEPO的定量检测．     

应用微卫星标记对雌核发育银鲫的遗传多样性初探

利用Crooijmans et al.(1997)分离的包含CA重复单元的普通鲤鱼（Cyprinus carpino.L)的8个微卫星DNA标记,对银鲫（Carassius auratus gibelio Bloch)的5个不同雌核发育系的24尾个体进行PCR扩增。分析电泳结果发现,除MFW28未能在银鲫中稳定地扩增出相应的同源序列,其余的7对引物扩增的重复性和稳定性都很好,随引物不同,各等位基因数为1-14个,大小在100-506bp。在MFW1、MFW4、MFW19、MFW20、MFW23和MFW246个微卫星的扩增图谱中,不同的雌核发育系扩增出各自独特的图谱,而同一系内的不同个体间具有高度的遗传同质性,但仍然在个别个体中检测到少量的多态片段。不同系间的扩增图谱呈现出高度的遗传异质性,共鉴定出23个可以用于有效区分5个不同雌核发育系的分子标记。这5个微卫星标记反映了银鲫5个雌核发育系间的相互亲缘关系,其中P和A系同属一个雌核发育系,F系起源于E系,A、D和E系可能分别独立地起源于不同的杂交事件,鉴定的微卫星分子标记为进行银鲫群体遗传学和进化遗传学研究,以及银鲫的分子标记育种和进行基因组作图提供了理想的工具。     

治疗性克隆与体细胞重编程：殊途同归

治疗性克隆和体细胞重编程是制备患者特异性自体干细胞的两种不同策略,近期已取得了重大的研究进展.治疗性克隆是通过体细胞核移植后形成克隆囊胚进而获得胚胎干细胞,体细胞重编程则是将特异性转录因子导入到体细胞核中而建立诱导性多潜能干细胞(induced pluripotent stem cells,iPS细胞).两者在方法学路径、技术难题、伦理争议等方面各不相同,但在应用研究层面上都涉及到干细胞的定向诱导分化、细胞移植治疗等相同的问题.本文总结了这两种生物技术的研究进展及其异同点.     

Neurotrophic Requirements of Human Motor Neurons Defined Using Amplified and Purified Stem Cell-Derived Cultures

Human motor neurons derived from embryonic and induced pluripotent stem cells (hESCs and hiPSCs) are a potentially important tool for studying motor neuron survival and pathological cell death. However, their basic survival requirements remain poorly characterized. Here, we sought to optimize a robust survival assay and characterize their response to different neurotrophic factors. First, to increase motor neuron yield, we screened a small-molecule collection and found that the Rho-associated kinase (ROCK) inhibitor Y-27632 enhances motor neuron progenitor proliferation up to 4-fold in hESC and hiPSC cultures. Next, we FACS-purified motor neurons expressing the Hb9::GFP reporter from Y-27632-amplified embryoid bodies and cultured them in the presence of mitotic inhibitors to eliminate dividing progenitors. Survival of these purified motor neurons in the absence of any other cell type was strongly dependent on neurotrophic support. GDNF, BDNF and CNTF all showed potent survival effects (EC₅₀ 1–2 pM). The number of surviving motor neurons was further enhanced in the presence of forskolin and IBMX, agents that increase endogenous cAMP levels. As a demonstration of the ability of the assay to detect novel neurotrophic agents, Y-27632 itself was found to support human motor neuron survival. Thus, purified human stem cell-derived motor neurons show survival requirements similar to those of primary rodent motor neurons and can be used for rigorous cell-based screening.     

Effects of crop plants on abundance of Pochonia chlamydosporia and other fungal parasites of root‐knot and potato cyst nematodes

The effects of a host plant on reproduction/abundance of fungal populations in relation to soil nutrients released by plants in the rhizosphere were studied. Abundance in the soil and potato rhizosphere of the fungi Paecilomyces lilacinus, Monographella cucumerina (CABI 380408) and Pochonia chlamydosporia var. chlamydosporia (Pc280, potato cyst nematode biotype) and P. chlamydosporia var. catenulata (Pc392, root‐knot nematode biotype) were assessed. The different ability of break crops (oilseed rape, sugarbeet and wheat) in the potato rotation to support Pa. lilacinus, Pochonia isolates Pc280 and Pc392 and abundance of the latter two isolates in soil and rhizosphere of potato plants infected with Meloidogyne incognita were also studied. Potato chits and crop seedlings were planted into boiling tubes containing 5000 chlamydospores or conidia g^?1 in acid washed sand (pH 6) and kept in a growth chamber at 20°C, and 16 h of light for up to 9 weeks. The abundance of the fungi in sand (fallow) differed significantly between fungal species, being in general less abundant in the absence than in the presence of the plant, although there was no interaction between plant species and fungal isolate. There was evidence of a different response to Me. incognita for Pc392 than for Pc280 but there was no significant effect of the presence of the nematode on the rate of increase of the fungus.     

Different seasonal feeding activity of diverse herbivores in two temperate forests

The aim of the present study was to understand the effects of abiotic conditions on seasonal feeding activity of diverse herbivores on the same oak tree species in two different forests. We tracked changes in herbivore feeding activities on an oak tree species (Quercus serrata) in two localities: a low elevation small hillock forest patch (Muan, MN) and a middle elevation mountain forest patch (Mt. Jirisan, JR). A total of five sites were selected in each of two forest localities. Data for leaf expansion, leaf chemical qualities, leaf damage ratio, and numbers of lepidopteran caterpillars were collected during spring (May) and summer (July to August), 2012. Leaf expansion rate was higher at the low hillock forest than the mid‐mountain forest from spring to summer. Nitrogen and carbon content decreased seasonally at both localities. Lepidopteran larval diversity was high in the mid‐mountain forest, and two‐way ANOVA showed that species richness of lepidopteran larvae was significantly affected by the interaction between season and locality. Leaf damage by all herbivores was higher in the low hillock forest than the mid‐mountain forest in spring, but was higher in the mid‐mountain forest in summer. Relative proportion of general herbivores increased from spring to summer in the mid‐mountain forest, but not in the low hillock forest. Canonical Correspondence Analysis (CCA) ordination showed that altitude‐ and season‐related variables were significant species and environment interaction factors. Our data indicate that locality and temperature disproportionally affected the feeding activities of diverse herbivores in two different temperate forests.     

Endothelial Transient Receptor Potential Conical Channel (TRPC)-3 Activation Induces Vasogenic Edema Formation in the Rat Piriform Cortex Following Status Epilepticus

Transient receptor potential canonical channel (TRPC) is a nonselective cation channel permeable to Ca²⁺, which express in many cell types, including neurons. However the alterations in TRPC receptor expressions in response to status epilepticus (SE) have not been explored. Therefore, the present study was designated to elucidate the roles of TRPC3 in neuronal death and vasogenic edema within the rat piriform cortex (PC) following SE. In non-SE animals, TRPC3 immunoreactivity was abundantly detected in the PC. Following SE, TRPC3 immunoreactivity was increased in neurons. Furthermore, TRPC3 expression was detected in endothelial cells that did not contain it in non-SE animals. Loss of SMI-71 (a blood–brain barrier antigen) immunoreactivity was also observed in TRPC3 positive endothelial cells. In addition, FJB positive neurons and vasogenic edema were noticeably detected in the PC. To directly determine whether TRPC3 activation is correlated to SE-induced vasogenic edema formation and neuronal damages in the PC, the effect of Pyr-3 (a TRPC3 antagonist) on SE-induced insults were investigated. Pyr-3 infusion effectively attenuated vasogenic edema in the PC as compared to the vehicle. Therefore, our findings indicate that TRPC3 activation/overexpression induced by SE may involve BBB disruption and neuronal damages in the rat PC following SE. Therefore, the present study was TRPC3 may play an important role in SE-induced vasogenic edema formation through BBB disruptions in the rat PC.