Valuing urban green spaces in mitigating climate change: A city‐wide estimate of aboveground carbon stored in urban green spaces of China's Capital

Urban green spaces provide manifold environmental benefits and promote human well‐being. Unfortunately, these services are largely undervalued, and the potential of urban areas themselves to mitigate future climate change has received little attention. In this study, we quantified and mapped city‐wide aboveground carbon storage of urban green spaces in China's capital, Beijing, using field survey data of diameter at breast height (DBH) and tree height from 326 field survey plots, combined with satellite‐derived vegetation index at a fine resolution of 6 m. We estimated the total amount of carbon stored in the urban green spaces to be 956.3 Gg (1 Gg = 10⁹ g) in 2014. There existed great spatial heterogeneity in vegetation carbon density varying from 0 to 68.1 Mg C ha^‐1, with an average density of 7.8 Mg C ha^?1. As expected, carbon density tended to decrease with urban development intensity (UDI). Likely being affected by vegetation cover proportion and configuration of green space patches, large differences were presented between the 95th and 5th quantile carbon density for each UDI bin, showing great potential for carbon sequestration. However, the interquartile range of carbon density narrowed drastically when UDI reached 60%, signifying a threshold for greatly reduced carbon sequestration potentials for higher UDI. These findings suggested that urban green spaces have great potential to make contribution to mitigating against future climate change if we plan and design urban green spaces following the trajectory of high carbon density, but we should be aware that such potential will be very limited when the urban development reaches certain intensity threshold.     

TAK1 is an essential regulator of BMP signalling in cartilage

TGFβ activated kinase 1 (TAK1), a member of the MAPKKK family, controls diverse functions ranging from innate and adaptive immune system activation to vascular development and apoptosis. To analyse the in vivo function of TAK1 in cartilage, we generated mice with a conditional deletion of Tak1 driven by the collagen 2 promoter. Tak1^col2 mice displayed severe chondrodysplasia with runting, impaired formation of secondary centres of ossification, and joint abnormalities including elbow dislocation and tarsal fusion. This phenotype resembled that of bone morphogenetic protein receptor (BMPR)1 and Gdf5-deficient mice. BMPR signalling was markedly impaired in TAK1-deficient chondrocytes as evidenced by reduced expression of known BMP target genes as well as reduced phosphorylation of Smad1/5/8 and p38/Jnk/Erk MAP kinases. TAK1 mediates Smad1 phosphorylation at C-terminal serine residues. These findings provide the first in vivo evidence in a mammalian system that TAK1 is required for BMP signalling and functions as an upstream activating kinase for Smad1/5/8 in addition to its known role in regulating MAP kinase pathways. Our experiments reveal an essential role for TAK1 in the morphogenesis, growth, and maintenance of cartilage.     

克鲁维酵母Y-85菊粉酶的纯化和性质

克鲁维酵母(Kluyveromyces sp.)Y-85产生的胞内菊粉酶(endocellular inulinase)和胞外菊粉酶(exocellular inulinase)粗酶液分别经PEG6000-磷酸盐缓冲液双水相抽提得部分纯化酶液。前者进一步用硫酸铵分级沉淀、Protein-PAK DEAE离子交换、Protein-PAK200SW凝胶过滤后得到两个菊粉酶组分EⅠ和EⅡ;后者采用DEAE-Sephacel离子交换、Sephadex G150凝胶过滤后得到菊粉酶Eexo。经Waters 650E蛋白纯化系统鉴定,三者均呈单一的对称峰;EⅠ和EⅡ达聚丙烯酰胺盘状凝胶电泳纯。EⅠ、EⅡ和Eexo的分子量分别为42kD、65kD和57kD;三者均为糖蛋白,多糖含量分别为30％、35％和25％;I/S(Inulinaseactivity/Sucrase activity)比值分别为0.086、0.078和0.072;三者均属外切菊粉酶。EⅠ、EⅡ和Eexo酶反应最适pH分别为4.6、4.5和4.6,最适温度分别为52℃、52℃和55℃;Ag^+、Hg^(2+)和PCMB对酶活性有强烈的抑制作用;三者水解菊芋粉糖液的产物均为果糖(86.5％)和葡萄糖(13.5％)。     

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．     

植物小RNAs的研究进展

小RNAs(长度小于40 nt)是nc-RNAs重要的一部分,现在植物中已发现了多种小RNAs,如小干扰RNAs(siRNAs)、微小RNAs(miRNAs)、反式作用的小干扰RNAs、天然反义转录小干扰RNAs、异染色质小干扰RNAs、长小片段小干扰RNAs、天然反义转录的微小RNAs及其一些未命名的小RNAs.成熟的小RNAs聚集相关的蛋白质因子,可以抑制转录,导致转录水平的基因沉默(TGS);或介导目标mRNA的剪切,抑制翻译,导致转录后水平基因沉默(PTGS).就这些植物小RNAs产生及其作用的研究进展作一概述     

Aromatic‐interaction‐mediated inhibition of β‐amyloid assembly structures and cytotoxicity

Abnormal aggregation of β‐amyloid (Aβ) peptide plays an important role in the onset and progress of Alzheimer's disease (AD); hence, targeting Aβ aggregation is considered as an effective therapeutic strategy. Here, we studied the aromatic‐interaction‐mediated inhibitory effect of oligomeric polypeptides (K8Y8, K4Y8, K8W8) on Aβ42 fibrillization process. The polypeptides containing lysine as well as representative aromatic amino acids of tryptophan or tyrosine were found to greatly suppress the aggregation as evaluated by thioflavin T assay. Circular dichroism spectra showed that the β‐sheet formation of Aβ42 peptides decreased with the polypeptide additives. Molecular docking studies revealed that the oligomeric polypeptides could preferentially bind to Aβ42 through π–π stacking between aromatic amino acids and Phe19, together with hydrogen bonding. The cell viability assay confirmed that the toxicity of Aβ42 to SH‐SY5Y cells was markedly reduced in the presence of polypeptides. This study could be beneficial for developing peptide‐based inhibitory agents for amyloidoses. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.     

Macrophage migration inhibitory factor (MIF) interacts with Bim and inhibits Bim-mediated apoptosis

The pro-apoptotic Bcl-2 family member Bim acts as a sensor for apoptotic stimuli and initiates apoptosis through the mitochondrial pathway. To identify novel regulators of Bim, we employed the yeast two-hybrid system and isolated the human gene encoding macrophage migration inhibitory factor (MIF), a ubiquitously expressed proinflammatory mediator that has also been implicated in cell proliferation, the cell cycle and carcinogenesis. The interaction between MIF and Bim was confirmed by both in vitro and in vivo protein interaction assays. Intriguingly, protein complexes between MIF and the three major Bim isoforms (BimEL/BimL/BimS) could be detected in HEK293 and K562 cells, especially in cells undergoing apoptosis. Moreover, exogenous expression of MIF partially inhibited Bim-induced apoptosis in HEK293 cells. SiRNA-mediated knockdown of MIF increased apoptosis in K562 cells exposed to the chemical oxidant diamide. Endogenous MIF may regulate the pro-apoptotic activity of Bim and inhibit the release of cytochrome c from mitochondria.     

重组人维甲酸X受体α的克隆与表达及其与甲状腺受体的结合

维甲酸X受体α(Retinoid X receptor-α,RXR-α)属于核受体家族,在调节基因转录及信号转导方面发挥着重要的作用。为了深入研究RXR-α的生物学作用,文章利用RT-PCR技术扩增了人RXR-α基因,并将其克隆入原核表达载体pQE-30Xa,转化大肠杆菌M15[PREP4],异丙基硫代-β-D-半乳糖苷(IPTG)诱导表达,SDS-PAGE可见与预期大小相符的蛋白条带,Western blotting证实该条带为重组人RXR-α蛋白,并用Ni2-NTA柱进行亲和层析纯化。免疫共沉淀结果显示其具有与TRβ1结合的能力。电泳迁移率改变实验(EMSA)显示RXR-α与TRβ1形成的杂二聚体具有与DNA结合的能力。结果显示,文章已成功建立了重组人RXR-α的大肠杆菌表达系统,表达产物具有很好的生物学活性。     

Long non‐coding RNA expressed in macrophage co‐varies with the inflammatory phenotype during macrophage development and polarization

Advances in microarray, RNA‐seq and omics techniques, thousands of long non‐coding RNAs (lncRNAs) with unknown functions have been discovered. LncRNAs have presented a diverse perspective on gene regulation in diverse biological processes, especially in human immune response. Macrophages participate in the whole phase of immune inflammatory response. They are able to shape their phenotype and arouse extensive functional activation after receiving physiological and pathological stimuli. Emerging studies indicated that lncRNAs participated in the gene regulatory network during complex biological processes of macrophage, including macrophage‐induced inflammatory responses. Here, we reviewed the existing knowledges of lncRNAs in the processes of macrophage development and polarization, and their roles in several different inflammatory diseases. Specifically, we focused on how lncRNAs function in macrophage, which might help to discover some potential therapeutic targets and diagnostic biomarkers.     

Environmental Drivers and Spatial Prediction of the Critically Endangered Species <i>Thuja sutchuenensis</i> in Sichuan-Chongqing,China

Identifying the ecological environment suitable for the growth of Thuja sutchuenensis and predicting other potential distribution areas are essential to protect this endangered species. After selecting 24 environmental factors that could affect the distribution of T. sutchuenensis, including climate, topography, soil and Normalized Difference Vegetation Index (NDVI), we adopted the Random Forest-MaxEnt integrated model to analyze our data. Based on the Random Forest study, the contribution of the mean temperature of the warmest quarter, mean temperature of the coldest quarter, annual mean temperature and mean temperature of the driest quarter was large. Based on MaxEnt model prediction outputs, the potential distribution map not only identified areas that originally recorded T. sutchuenensis, such as Xuanhan County, Kai County and Chengkou County, but also identified highly suitable distribution areas where T. sutchuenensis may exist, including Wanyuan County, Sichuan Province, and the junction of Chongqing and Hubei Province. This provides a more explicit geographic range for ex situ conservation and reintroduction of T. sutchuenensis. Our results also indicate that, in addition to climate factors, topography and soil factors are also important environmental factors that affect distribution. This provides a theoretical basis for subsequent laboratory construction to simulate the indoor growth of T. sutchuenensis.