城市景观生态风险评估框架与实践——以北京天坛地区为例

当前,城市景观生态风险研究缺少科学合理、方便实用的评估框架。作者基于景观生态风险评估基本范式,明确了城市景观生态服务价值的测算方法,分析了引起生态损害的自然因素和人类活动因素,形成了城市景观生态风险评估的技术框架和参数体系;继而以北京天坛地区为研究区,开展了典型城市景观生态风险的定量评估。结果表明:(1)天坛地区景观生态价值总量约为2.41亿元。区域的历史文化价值最高,教育和美学景观价值紧随其后。(2)城市景观生态受损概率呈现"北高南低"的空间分布格局。生态受损概率的高值区面积占整个区域总面积的22.2%,主要分布在珠市口、磁器口和崇文门附近区域。(3)城市景观生态风险呈现"北低南高"的空间分布格局。高风险区主要分布在天坛公园内的文物建筑周边。本研究提供了一个可参考的城市景观生态风险评估应用框架,对生态风险评估中的不确定性进行了讨论,研究针对天坛案例区的具体结论有助于城市管理者避免潜在的风险。     

GenoBaits Soy40K: a highly flexible and low-cost SNP array for soybean studies

<正>Dear Editor,Soybean(Glycine max [L.] Merr.) provides more than half of the oilseeds and more than a quarter of protein worldwide. It is estimated that the production of soybean has to be doubled by 2050 to meet the needs of the rapidly increasing consumption of soybean seeds along with a continuously increasing population(Ray et al., 2013). As such, development of a genotyping platform with high throughput, high efficiency and high precision but low-cost is urgently needed to accelerate...     

强化产电微生物与电极间电子传递速率的研究进展

产电微生物是微生物燃料电池、电解池和电合成等微生物电化学技术(Microbial electrochemical technologies,METs)的研究基础.产电微生物与电极界面间的胞外电子传递(Extracellular electron transfer,EET)效率低以及生物被膜形成能力弱限制了METs在有机...     

Development of a fluorescent probe hydrolysis-insulated isothermal PCR for rapid and sensitive on-site detection of African swine fever virus

Highlights
1. A probe-based insulated isothermal PCR (iiPCR) assay was developed for rapid and onsite detection of ASFV.
2. The developed iiPCR showed similar sensitivity and specificity with OIE recommended real-time PCR.
3. Blood samples could be directly applied as PCR template in iiPCR without DNA extraction.     

Quorum Sensing System Used as a Tool in Metabolic Engineering

Quorum sensing (QS) is a ubiquitous cell–cell communication mechanism in microbes that coordinates population‐level cell behaviors, such as biofilm production, virulence, swarming motility, and bacterial persistence. Efforts to engineer QS systems to take part in metabolic network regulation represent a promising strategy for synthetic biology and pathway engineering. Recently, design, construction, and implementation of QS circuits for programmed control of bacterial phenotypes and metabolic pathways have gained much attention, but have not been reviewed recently. In this article, the architectural organizations and genetic contributions of the naturally occurring QS components to understand the mechanisms are summarized. Then, the most recent progress in application of QS toolkits to develop synthetic networks for novel cell behaviors creation and metabolic pathway engineering is highlighted. The current challenges in large‐scale application of these QS circuits in synthetic biology and metabolic engineering fields are discussed and future perspectives for further engineering efforts are provided.     

MiR‐616‐3p modulates cell proliferation and migration through targeting tissue factor pathway inhibitor 2 in preeclampsia

Objectives

Despite improvements in diagnosis and treatment, preeclampsia (PE) continues to pose a significant risk of maternal and foetal morbidity and mortality if not addressed promptly. An increasing number of studies have suggested that tissue factor pathway inhibitor 2 (TFPI2) acts as a suppressor gene, possibly inhibiting multiple serine proteases affecting cell proliferation and migration. It plays an essential role in the occurrence and development of PE, but the pathogenesis remains unclear.

Materials and methods

In our research, we performed western blotting, immunohistochemistry and qPCR assays to investigate TFPI2 and miR‐616‐3p expression in preeclamptic placental tissues. Cell assays were performed in HTR‐8/SVneo and JEG3 cell lines. Cell proliferation and migration events were investigated by MTT, EdU and transwell assays. In conjunction with bioinformatics analysis, luciferase reporter assays were performed to elucidate the mechanism by which miR‐616‐3p binds to TFPI2 mRNA.

Results

We established that TFPI2 protein levels were significantly upregulated in PE placental tissues. In addition, we found that miR‐616‐3p binds specifically to the 3′‐UTR region of TFPI2 mRNA. Furthermore, miR‐616‐3p knockdown or TFPI2 overexpression substantially impaired cell growth and migration, whereas miR‐616‐3p upregulation or TFPI2 knockdown stimulated cell proliferation and migration. This miR‐616‐3p / TFPI2 axis was also found to affect the epithelial‐mesenchymal transition process in PE.

Conclusions

Our results demonstrated that TFPI2 plays a vital role in the progression of PE and might provide a prospective therapeutic strategy to mitigate the severity of the disorder.

     

Genetic variation within and among populations of a wild rice Oryza granulata from China detected by RAPD and ISSR markers

Genetic variation within and between five populations of Oryza granulata from two regions of China was investigated using RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat amplification) markers. Twenty RAPD primers used in this study amplified 199 reproducible bands with 61 (30.65%) polymorphic; and 12 ISSR primers amplified 113 bands with 52 (46.02%) polymorphic. Both RAPD and ISSR analyses revealed a low level of genetic diversity in wild populations of O. granulata. Furthermore, analysis of molecular variance (AMOVA) was used to apportion the variation within and between populations both within and between regions. As the RAPD markers revealed, 73.85% of the total genetic diversity resided between the two regions, whereas only 19.45% and 6.70% were present between populations within regions and within a population respectively. Similarly, it was shown by ISSR markers that a great amount of variation (49.26%) occurred between the two regions, with only 38.07% and 12.66% between populations within regions and within a population respectively. Both the results of a UPGMA cluster, based on Jaccard coefficients, and pairwise distance analysis agree with that of the AMOVA partition. This is the first report of the partitioning of genetic variability within and among populations of O. granulata at the DNA level, which is in general agreement with a recent study on the same species in China using allozyme analysis. Our results also indicated that the percentage of polymorphic bands (PPB) detected by ISSR is higher than that detected by RAPD. It seems that ISSR is superior to RAPD in terms of the polymorphism detected and the amplification reproducibility. Received: 29 March 2000 / Accepted: 15 May 2000     

Fluorescent metal nanoshell and CK19 detection on single cell image

In this article, we report the synthesis strategy and optical properties of a novel type of fluorescence metal nanoshell when it was used as imaging agent for fluorescence cell imaging. The metal nanoshells were made with 40 nm silica cores and 10 nm silver shells. Unlike typical fluorescence metal nanoshells which contain the organic dyes in the cores, novel metal nanoshells were composed of Cy5-labelled monoclonal anti-CK19 antibodies (mAbs) on the external surfaces of shells. Optical measurements to the single nanoparticles showed that in comparison with the metal free labelled mAbs, the mAb-Ag complexes displayed significantly enhanced emission intensity and dramatically shortened lifetime due to near-field interactions of fluorophores with metal. These metal nanoshells were found to be able to immunoreact with target cytokeratin 19 (CK19) molecules on the surfaces of LNCAP and HeLa cells. Fluorescence cell images were recorded on a time-resolved confocal microscope. The emissions from the metal nanoprobes could be clearly isolated from the cellular autofluorescence backgrounds on the cell images as either individuals or small clusters due to their stronger emission intensities and shorter lifetimes. These emission signals could also be precisely counted on single cell images. The count number may provide an approach for quantifying the target molecules in the cells.