纳络酮对东方蝾螈胚胎表皮传导的阻断作用

在胚胎发育的一定时期,表皮细胞呈现较强的β-内啡肽阳性免疫反应,而这时期正是表皮传导最活跃的时期。为了探索胚胎表皮传导和β-内啡肽-类阿片样多肽之间是否有关系,本实验采用纳络酮处理,发现表皮传导消失,待纳络酮作用消除后,表皮传导现象又再出现,说明纳络酮在胚胎表皮细胞传导中起了阻断的作用。     

Targeting nucleolin to obstruct vasculature feeding with an intelligent DNA nanorobot

A prototype of DNA nanorobot with the ability to transport molecular payloads was designed to target cancer cells in tissue culture. Moreover, a further step was taken to succeed in the first in vivo application of the DNA nanorobot for cancer therapy. The robot was constructed using aptamer and DNA origami to fold a 90‐nm tubular device to carry the blood coagulation protease thrombin inside, shielded from circulating platelets and plasma fibrinogen. The recognition and binding of the aptamer to its tumour‐specific target molecule triggered the robot unfolding to expose thrombin to the blood, which in turn activated coagulation at the local tumour site, resulting in tumour necrosis and inhibition of tumour growth. Since all solid‐tumour feeding vessels are virtually the same, this strategy could be effective against many types of malignant diseases.     

创伤后应激障碍对慢性不可预见性应激抑郁模型的影响

目的:观察创伤后应激障碍(PTSD)对慢性不可预见性应激(CUS)抑郁模型的影响。方法:采用足底电击的方法建立大鼠创伤后应激障碍模型。成年雄性S-D大鼠40只随机分为四组(n=10):对照组(C组)、PTSD组、CUS组、PTSD+CUS组(P+C组)。在1、7、14、21天测量大鼠体重,并行糖水偏好和强迫游泳实验,在7、14、21天做条件性恐惧实验。结果:与C组相比,CUS组和P+C组体重增加缓慢,PTSD组体重正常。CUS组于第21天出现糖水消耗比例降低,强迫游泳不动时间增加。P+C组于第14天即出现上述抑郁表现。条件性恐惧实验中,PTSD组与PTSD+CUS组僵直时间显著增加,CUS组无明显变化。结论:创伤后应激障碍的动物更易产生抑郁表现。     

Production of genetically modified pigs expressing human insulin and C-peptide as a source of islets for xenotransplantation

Transgenic Research - Islet xenotransplantation is a promising treatment for type I diabetes. Numerous studies of islet xenotransplantation have used pig-to-nonhuman primate transplantation models....     

Spatial patterns and interspecific associations among trees at different stand development stages in the natural secondary forests on the Loess Plateau,China

Quercus wutaishansea populations on the Loess Plateau are currently becoming more dominant in natural secondary forests, whereas Pinus tabulaeformis is declining. In the present paper, the diameter class (instead of age) was used to classify the different growth stages as juvenile, subadult, or adult, and the univariate function g(r) was used to analyze the dynamic changes in spatial patterns and interspecific associations in three 1‐ha tree permanent plots on the Loess Plateau, NW China. Our results suggested that the niche breadth changed with the development stage. The diameter distribution curve was consistent with the inverted “J” type, indicating that natural regeneration was common in all three plots. There was a close relationship between the spatial pattern and scale, which showed significant aggregation at small distances, and became more random as distance increased, but in the Pinus + Quercus mixed forests, the whole species were aggregated at distances up to 50 m. The degree of spatial clumping decreased from juvenile to subadult and from subadult to adult. The spatial pattern also differed at different growth stages, likely due to strong intraspecific competition. Associations among different growth stages were positively correlated at small scales. Our study is important to the understanding of the development of the Q. wutaishansea forests; thus, the spatial dynamic change features should be received greater attention when planning forest management and developing restoration strategies on the Loess Plateau.     

异源多角体蛋白对家蚕核型多角体病毒粒子的包装

利用PCR方法从AcMNPV基因组DNA中分离出多角体蛋白基因 ,将该扩增片段克隆到转移载体pBacPAK8中 ,得到重组转移载体pOAc。将该质粒DNA与线性化的Bm BacPAK6病毒基因组DNA共传染BmN细胞 ,得到了能形成多角体且不产生蓝色空斑的重组病毒hp BmNPV。纯化该重组病毒的多角体颗粒 ,并对多角体蛋白、病毒核酸及多角体病毒颗粒进行分析 ,发现AcMNPV的多角体蛋白能在家蚕细胞中大量表达且能在细胞内识别家蚕核型多角体病毒并组装成多角体颗粒 ;病毒基因组DNA因部分交换 ,其酶切行为发生了相应的变化 ;电镜观察发现经AcMNPV多角体蛋白包装的家蚕核型多角体病毒的多角体颗粒大小为1 2 μm～ 2 9μm ,明显小于野生型家蚕核型多角体病毒的多角体颗粒     

Spring colonisation of orchards by Anthonomus pomorum from adjacent forest borders

The early-season dispersal of the overwintered apple blossom weevil, Anthonomus pomorum (L.) (Coleoptera: Curculionidae), is a crucial stage in the colonisation of dwarf apple orchards adjacent to forests. We have conducted release-recapture studies with 1700 to 4000 marked weevils at two orchard sites in Switzerland over 2 years to characterise the spatial and temporal pattern of the dispersal process. The dispersal and colonisation of orchards in spring by overwintered weevils is dependent upon the prevailing temperature.An orientated dispersal from the forest border to the centre of the orchard was observed consistently, irrespective of the angle of the apple tree rows with respect to the forest border or of climatic conditions. The average dispersal distance of the weevils was 19 m. Approximately one third of the weevil population remained on the first tree encountered, the remainder of the population moved over short distances mainly along the tree rows. This dispersal pattern led to a strong edge effect with higher numbers of weevils occurring at the edges adjoining the forests as compared to the centre of orchards. The relevance of these findings to population dynamics and management of the pest is discussed.     

Enhanced Stability and Thickness‐Independent Oxygen Evolution Electrocatalysis of Heterostructured Anodes with Buried Epitaxial Bilayers

Achieving high oxygen evolution reaction (OER) activity while maintaining performance stability is a key challenge for designing perovskite structure oxide OER catalysts, which are often unstable in alkaline environments transforming into an amorphous phase. While the chemical and structural transformation occurring during electrolysis at the electrolyte–catalyst interface is now regarded as a crucial factor influencing OER activity, here, using La_0.7Sr_0.3CoO_3?δ (LSCO) as an active OER catalyst, the critical influence of buried layers on the oxidation current stability in nanoscopically thin, chemically and structurally evolving, catalyst layers is revealed. The use of epitaxial thin films is demonstrated to engineer both depletion layer widths and chemical stability of the catalyst support structure resulting in heterostructured anodes that maintain facile transport kinetics across the electrolyte–anode interface for atomically thin (2–3 unit cells) LSCO catalyst layers and greatly enhanced oxidation current stability as the perovskite structure OER catalysts chemically and structurally transform. This work opens up an approach to design robust and active heterostructured anodes with dynamically evolving ultrathin OER electrocatalyst layers for future green fuel technologies such as conformal coatings of high‐density 3D anode topologies for water splitting.