miR-329 suppresses the growth and motility of neuroblastoma by targeting KDM1A

MicroRNAs (miRNAs) act as key regulators of multiple cancers. miR-329 functions as a tumor suppressor in some malignancies. However, its role in neuroblastoma remains poorly understood. We found that miR-329 was decreased in metastatic tumor tissues compared with matched primary tumor tissues. Forced overexpression of miR-329 substantially suppressed cell proliferation, colony formation, migration, and invasion of neuroblastoma cells. Lysine-specific demethylase 1 (KDM1A) was found to be a target of miR-329. Furthermore, down-regulation of KDM1A by shRNA performed similar effects with overexpression of miR-329. Overexpression of KDM1A partially reversed the tumor suppressive effects of miR-329 in neuroblastoma cells. Collectively, miR-329 may suppress neuroblastoma cell growth and motility partially by targeting KDM1A.     

Rotating‐Disk‐Based Direct‐Current Triboelectric Nanogenerator

An innovative design is reported of a direct‐current triboelectric nanogenerator (DC‐TENG) based on a rotating disk design for harvesting rotational mechanical energy. The DC‐TENG consists of two disks and two pairs of flexible electric brushes that are made of carbon fiber and contact two electrodes, respectively. During the rotation, two disks have distinct triboelectric polarities for a cyclic in‐plane charge separation between them and an alternating current is generated between the two electrodes. Because of the sliding contact and automatically switch between the electric brushes and the two electrodes, the current is reversed in the second half of the cycle and a direct current is generated. The role that the rotating speed and the segmentation number have is thoroughly investigated and shows that there is direct current enhancement not only at higher speed but also with more segments. The DC‐TENG has been demonstrated as a constant current source for directly and continuously driving electronic devices and/or charging an energy storage unit without a rectifier bridge. This work presents a novel DC‐TENG technology and opens up more potential applications for harvesting rotational mechanical energy and powering electronics.     

Self‐assembly of regenerated silk fibroin from random coil nanostructures to antiparallel β‐sheet nanostructures

In this work, we studied the effects of incubation concentration and time on the self‐assembly behaviors of regenerated silk fibroin (RSF). Our results showed the assembly ways of RSF were concentration‐dependent and there were four self‐assembly ways of RSF: (i) At relatively low concentration (≤0.015%), RSF molecules assembled into protofilaments (random coil), and then the thickness decreased and the secondary conformation changed to antiparallel β‐sheet; (ii) at the concentration of 0.015%, RSF molecules assembled into protofilaments (random coil), and then assembled into protofibrils (antiparallel β‐sheet). The protofibrils experienced the appearance and disappearance of phase periodic intervals in turn; (iii) at the concentration of 0.03%, RSF molecules assembled into bead‐like oligomers (random coil), and then assembled into protofibrils (antiparallel β‐sheet), and finally the height and phase periodic intervals of RSF protofibrils disappeared in turn; and (iv) at the relatively high concentration (≥0.15%), RSF molecules assembled into protofilaments (random coil), then aggregated into blurry cuboid‐like micelles (random coil), and finally self‐arranged to form smooth and clear cuboid‐like micelles (antiparallel β‐sheet). These results provide useful insights into the process by which the RSF molecules self‐assemble into protofilaments, protofibrils and micelles. Furthermore, our work will be beneficial to basic understanding of the nanoscale structure formations in different silk‐based biomaterials. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1181–1192, 2014.     

Substantial reorganization of China's tropical and subtropical forests: based on the permanent plots

There is evidence that climate change induced tree mortalities in boreal and temperate forests and increased forest turnover rates (both mortality and recruitment rates) in Amazon forests. However, no study has examined China's tropical and subtropical evergreen broadleaved forests (TEBF) that cover >26% of China's terrestrial land. The sustainability of this biome is vital to the maintenance of local ecosystem services (e.g., carbon sequestration, biodiversity conservation, climatic regulation), many of which may influence patterns of atmospheric circulation and composition at regional to global scales. Here, we analyze time‐series data collected from thirteen permanent plots within China's unmanaged TEBF to study whether and how this biome has changed over recent decades. We find that the numbers of individuals and species for shrub and small tree have increased since 1978, whereas the numbers of individuals and species for tree have decreased over this same time period. The shift in species composition is accompanied by a decrease in the mean diameter at breast height (DBH) for all individuals combined. China's TEBF may thereby be transitioning from cohorts of fewer and larger individuals to ones of more and smaller individuals, which shows a unique change pattern differing from the documented. Regional‐scale drying is likely responsible for the biome's reorganization. This biome‐wide reconstitution would deeply impact the regimes of carbon sequestration and biodiversity conservation and have implications for the sustainability of economic development in the area.     

The Chiral Separation and Enantioselective Degradation of the Chiral Herbicide Napropamide

The chiral pesticide enantiomers often have different toxic effects and environmental behaviors, which suggests that the risk assessments should be on an enantiomeric level. In this work, the chiral separation of the napropamide enantiomers and the stereoselective degradation in tomato, cucumber, rape, cabbage, and soil were investigated. Napropamide enantiomers could be separated absolutely by high‐performance liquid chromatography (HPLC) using a Chiralpak IC column with a resolution factor of 11.75 under the optimized condition. Solid phase extraction (SPE) was used for cleanup of the enantiomers in the vegetable samples. The residue analysis method was validated. Good linearities (R² = 0.9997) and recoveries (71.43% ‐97.64%) were obtained. The limits of detection (LOD) were 0.05 mg/kg in soil and 0.20 mg/kg in vegetables. The results of degradation showed that napropamide dissipated rapidly in vegetables with half‐lives of only 1.13–2.21 days, but much more slowly in soil, with a half‐life of 11.95 d. Slight stereoselective degradation of the two enantiomers was only observed in cabbage, with enantiomeric fraction (EF) = 0.46, and there was no enantioselectivity in the other vegetables. The degradation of napropamide in the five matrixes was fast, and there was no enantioselectivity. Chirality 28:108–113, 2014. © 2014 Wiley Periodicals, Inc.     

Molecular photoacoustic tomography of breast cancer using receptor targeted magnetic iron oxide nanoparticles as contrast agents

In this report, we present a breast imaging technique combining high‐resolution near‐infrared (NIR) light induced photoacoustic tomography (PAT) with NIR dye‐labeled amino‐terminal fragments of urokinase plasminogen activator receptor (uPAR) targeted magnetic iron oxide nanoparticles (NIR830‐ATF‐IONP) for breast cancer imaging using an orthotopic mouse mammary tumor model. We show that accumulation of the targeted nanoparticles in the tumor led to photoacoustic contrast enhancement due to the high absorption of iron oxide nanoparticles (IONP). NIR fluorescence images were used to validate specific delivery of NIR830‐ATF‐IONP to mouse mammary tumors. We found that systemic delivery of the targeted IONP produced 4‐ and 10‐fold enhancement in photoacoustic signals in the tumor, compared to the tumor of the mice that received non‐targeted IONP or control mice. The use of targeted nanoparticles allowed imaging of tumors located as deep as 3.1 cm beneath the normal tissues. Our study indicates the potential of the combination of photoacoustic tomography and receptor‐targeted NIR830‐ATF‐IONP as a clinical tool that can provide improved specificity and sensitivity for breast cancer detection. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

环境变化对中国野生蜜蜂多样性的影响

蜜蜂尤其是野生蜜蜂对维持生态系统功能、保证粮食安全等方面具有重要的作用。近年来, 野生蜜蜂的栖息地由于天然林减少, 而现营造的又多为纯林, 以及大面积种植单一经济林而遭到了严重破坏和片断化。已有研究表明纯林、油茶(Camellia oleifera)和橡胶树(Hevea brasiliensis)经济林中的野生蜜蜂多样性较低。现代农业中新烟碱类杀虫剂、除草剂的大规模使用, 会对蜜蜂个体发育和行为产生不利影响。城市化进程潜在影响了蜜蜂的群落, 如郊区的蜜蜂平均物种丰富度要明显高于中心商业区; 废水、废气和粉尘对蜜蜂的觅食、生长发育等都具有不利影响; CO₂等温室气体导致的气候变暖影响了传粉蜜蜂与植物之间的互利共生关系, 造成时间或功能上的不匹配。综上所述, 我国的环境变化可能已导致中国野生传粉蜜蜂多样性的下降和种群的衰退。我国虽是传粉蜜蜂种质资源大国, 但缺乏种类和分布本底以及长期而有效的监测数据, 缺乏对蜜蜂多样性和种群下降机制的研究。因此亟待开展传粉蜜蜂调查、实施长期监测项目, 为之建立研究网络。并通过积累丰富的相关数据, 开展风险预测和评估, 用于管理和缓解传粉蜜蜂下降所带来的经济及非经济影响。     

Genetic analysis assessed by microsatellites for a diallel mating design of two geographical stocks of the blood clam <Emphasis Type="Italic">Tegillarca granosa</Emphasis>

To determine the potential for productive efficiency and genetic improvement in the blood clam Tegillarca granosa, four offspring populations (ZZ, ZK, KZ and KK) were produced from a diallel mating of two different geographical stocks (Z and K). The levels of genetic diversity and population structures of four populations were analyzed using 14 polymorphic microsatellites. The results showed that the mean observed heterozygosities (Ho) of reciprocal cross populations (ZK and KZ) was higher than those of pure populations(ZZ and KK). The largest values of genetic differentiation coefficient (F_st?=?0.067) and Nei’s unbiased genetic distance (Dc?=?0.263) were between ZK and KZ, and the smallest (F_st?=?0.020, Dc?=?0.116) were between ZZ and KK, which revealed that the largest genetic divergence was between the two reciprocal cross populations and the smallest was between two pure populations. This study demonstrated that the reciprocal cross populations of T. granosa had an extensive genetic difference and improvement, which may be advantageous for future breeding studies.     

Vascular smooth muscle cells direct extracellular dysregulation in aortic stiffening of hypertensive rats

Aortic stiffening is an independent risk factor that underlies cardiovascular morbidity in the elderly. We have previously shown that intrinsic mechanical properties of vascular smooth muscle cells (VSMCs) play a key role in aortic stiffening in both aging and hypertension. Here, we test the hypothesis that VSMCs also contribute to aortic stiffening through their extracellular effects. Aortic stiffening was confirmed in spontaneously hypertensive rats (SHRs) vs. Wistar‐Kyoto (WKY) rats in vivo by echocardiography and ex vivo by isometric force measurements in isolated de‐endothelized aortic vessel segments. Vascular smooth muscle cells were isolated from thoracic aorta and embedded in a collagen I matrix in an in vitro 3D model to form reconstituted vessels. Reconstituted vessel segments made with SHR VSMCs were significantly stiffer than vessels made with WKY VSMCs. SHR VSMCs in the reconstituted vessels exhibited different morphologies and diminished adaptability to stretch compared to WKY VSMCs, implying dual effects on both static and dynamic stiffness. SHR VSMCs increased the synthesis of collagen and induced collagen fibril disorganization in reconstituted vessels. Mechanistically, compared to WKY VSMCs, SHR VSMCs exhibited an increase in the levels of active integrin β1‐ and bone morphogenetic protein 1 (BMP1)‐mediated proteolytic cleavage of lysyl oxidase (LOX). These VSMC‐induced alterations in the SHR were attenuated by an inhibitor of serum response factor (SRF)/myocardin. Therefore, SHR VSMCs exhibit extracellular dysregulation through modulating integrin β1 and BMP1/LOX via SRF/myocardin signaling in aortic stiffening.