Expression analysis of banana MaECHI1 during fruit ripening with different treatments

The main function of endochitinase is believed to be pathogenesis related protein. However, more and more scientists reported the roles of endochitinase in plant growth and development. In order to investigate the role of endochitinase in postharvest banana fruit ripening, an endochitinase gene known as MaECHI1 had been isolated from a suppression subtractive hybridization (SSH) complementary deoxyribonucleic acid (cDNA) library. MaECHI1 was mainly expressed in banana fruit and flowers. Ethylene biosynthesis, gene expression and chitinase activities in different stages of postharvest banana fruit with or without ethylene and 1-methylcycle–propene (1-MCP) treatments were investigated. The results show that under ethylene treatment, banana ethylene production, gene expression, and chitinase activities increased markedly at the onset of banana ripening. Moreover, banana ethylene production and MaECHI1 gene expression peaks appeared earlier with ethylene treatment than with other treatment. MaECHI1 gene expression was markedly responsive to the fruit ripening process and to exogenous ethylene treatment.Keywords: Banana (Musa acuminata L.AAA), endochitinase gene expression, ethylene production fruit ripenin

miR-26 Induces Apoptosis and Inhibits Autophagy in Non-small Cell Lung Cancer Cells by Suppressing TGF-β1-JNK Signaling Pathway

Non-small cell lung cancer (NSCLC) is one of the causes of cancer mortality worldwide. The role of miR-26 in the development and progression of NSCLC remains largely unknown. In this study we found an abnormal expression of miR-26 in human NSCLC tissues. It was found that miR-26 mimics induced cell apoptosis and promoted caspase-3, 9 activities in human NSCLC cells. The miR-26 inhibitor enhanced the expression of the light chain 3 (LC3) protein and the autophagy related genes in NSCLC cells. Moreover, miR-26 regulated apoptosis and autophagy by inhibiting TGF-β expression in a JNK dependent manner. In addition, miR-26 mimics induced cell apoptosis, was involved in the endoplasmic reticulum stress (ERS) signaling pathway. Down-regulation of the ERS, inhibited apoptosis which was induced by miR-26 mimics in NSCLC cells. In in vivo studies, TUNEL staining revealed that the number of TUNEL positive cells of the tumor tissue in the miR-26 treatment group, were significantly increased in comparison with the control group, while the number of TUNEL positive cells in the tumor tissue were remarkably decreased in the groups treated with miR-26, combined with the TGF-β1 inhibitor or JNK inhibitor. Additionally, the immunoreactivity of TGF-β1 in the cells treated with the miR-26 inhibitor, decreased in comparison to the control group. Our results indicated that miR-26 induced apoptosis and inhibited autophagy in human NSCLC cells through the TGF-β1-JNK signaling pathway, suggesting that miR-26 could be a potential novel target for the treatment of NSCLC

Identification of compound heterozygous variants in the noncoding RNU4ATAC gene in a Chinese family with two successive foetuses with severe microcephaly

Background: Whole-exome sequencing (WES) over the last few years has been increasingly employed for clinical diagnosis. However, one caveat with its use is that it inevitably fails to detect disease-causative variants that occur within noncoding RNA genes. Our experience in identifying pathogenic variants in the noncoding RNU4ATAC gene, in a Chinese family where two successive foetuses had been affected by severe microcephaly, is a case in point. These foetuses exhibited remarkably similar phenotypes in terms of their microcephaly and brain abnormalities; however, the paucity of other characteristic phenotypic features had made a precise diagnosis impossible. Given that no external causative factors had been reported/identified during the pregnancies, we sought a genetic cause for the phenotype in the proband, the second affected foetus. Results: A search for chromosomal abnormalities and pathogenic copy number variants proved negative. WES was also negative. These initial failures prompted us to consider the potential role of RNU4ATAC, a noncoding gene implicated in microcephalic osteodysplastic primordial dwarfism type-1 (MOPD1), a severe autosomal recessive disease characterised by dwarfism, severe microcephaly and neurological abnormalities. Subsequent targeted sequencing of RNU4ATAC resulted in the identification of compound heterozygous variants, one being the most frequently reported MOPD1-causative mutation (51G>A), whereas the other was a novel 29T>A variant. Four distinct lines of evidence (allele frequency in normal populations, evolutionary conservation of the affected nucleotide, occurrence within a known mutational hotspot for MOPD1-causative variants and predicted effect on RNA secondary structure) allowed us to conclude that 29T>A is a new causative variant for MOPD1. Conclusions: Our findings highlight the limitations of WES in failing to detect variants within noncoding RNA genes and provide support for a role for whole-genome sequencing as a first-tier genetic test in paediatric medicine. Additionally, the identification of a novel RNU4ATAC variant within the mutational hotspot for MOPD1-causative variants further strengthens the critical role of the 5′ stem-loop structure of U4atac in health and disease. Finally, this analysis enabled us to provide prenatal diagnosis and genetic counselling for the mother’s third pregnancy, the first report of its kind in the context of inherited RNU4ATAC variants

Electronic structure and morphology of dark oxides on zinc generated by electrochemical treatment

European Union; state of North Rhine-Westphalia in the frame of the HighTech.NRW program; Salzgitter Mannesmann Forschung GmbH in the frame of the International Max Planck Research School for Surface and Interface Engineering in Advanced Materials (IMPRS-SurMat)Oxides formed by electrochemical treatment of metals frequently have properties and structures very different from the respective bulk oxides. Here, electronic structure and chemical composition were investigated for the oxide formed on polycrystalline zinc after electrochemical oxidation, and after subsequent reduction, in a Na2CO3 electrolyte. Photoluminescence and spectroscopic ellipsometry show the presence of states deep in the ZnO band gap in the oxidized sample, which consists of a highly disordered oxide. These states determine the absorption of light in the visible spectral range. After reduction, the characteristics of the ZnO electronic structure have disappeared, leaving a defect-dominated material with a band gap of similar to 1.8 eV. Complementary detailed analysis of the morphology of the resulting surfaces shows hexagon-shaped metallic Zn-"nanoplates" to be formed in the reduction step. The optical appearance of the surfaces is dark, because of their efficient extinction of light over a large part of the visible spectrum. The optical appearance is a result of changed surface morphology and electronic structure of the oxide film. Such materials may possess interesting applications in photocatalysis or photoelectrochemistry

Plasmonic photoluminescence for recovering native chemical information from surface-enhanced Raman scattering

表面增强拉曼光谱(SERS)可以提供高达单分子的检测灵敏度和特异的分子指纹信息，是一个非常有前景的分析技术。SERS增强主要源自贵金属纳米结构的局域表面等离激元共振(LSPR)效应。虽然SERS研究者早已意识到该效应强烈依赖于激光波长，并对不同频率的拉曼谱峰增强效果不同，但是迄今为止仍缺乏有效的方法对SERS谱峰相对强度进行可靠的矫正，也常有文献错误解读SERS强度信息，从而过度或错误地解释实验结果。 在该工作中，任斌教授课题组采用单粒子光谱技术从实验上直接检测SERS光谱和金属纳米粒子的光致发光谱(PL)，通过定量研究两者的关联，提出了一种普适的方法矫正LSPR对不同拉曼谱峰相对强度的影响，为理解表面物种构型和作用方式提供了本征的化学指纹信息。【Abstract】Surface-enhanced Raman scattering (SERS) spectroscopy has attracted tremendous interests as a highly sensitive label-free tool. The local field produced by the excitation of localized surface plasmon resonances (LSPRs) dominates the overall enhancement of SERS. Such an electromagnetic enhancement is unfortunately accompanied by a strong modification in the relative intensity of the original Raman spectra, which highly distorts spectral features providing chemical information. Here we propose a robust method to retrieve the fingerprint of intrinsic chemical information from the SERS spectra. The method is established based on the finding that the SERS background originates from the LSPR-modulated photoluminescence, which contains the local field information shared also by SERS. We validate this concept of retrieval of intrinsic fingerprint information in well controlled single metallic nanoantennas of varying aspect ratios. We further demonstrate its unambiguity and generality in more complicated systems of tip-enhanced Raman spectroscopy (TERS) and SERS of silver nanoaggregates.该工作得到国家自然科学基金委（项目批准号：21633005、21621091和J1310024）、科技部（项目批准号：2013CB933703、2016YFA0200601）、教育部等部门的大力资助与支持

Observing atomic layer electrodeposition on single nanocrystals surface by dark field spectroscopy

从单颗粒水平研究电化学表面和界面过程，特别是欠电位沉积是电化学领域的一个重要挑战。欠电位沉积通常仅涉及单原子层到亚单原子层的物种，但是能够显著调控金属表面电子结构，是制备高效电催化剂的一个重要的方法。然而目前在电化学环境下表征单个粒子表面单层原子的变化仍然是个巨大的挑战，针对上述挑战，任斌教授课题组发展了一套高灵敏的电化学暗场散射光谱装置，在不使用特殊光源的情况下，可以使得检测的粒径小至10-15 nm，灵敏度提高到亚单层原子。该工作是在任斌教授指导下，主要由化学化工学院已毕业博士生胡树（第一作者）完成。李剑锋教授及其课题组的博士生张月皎在单晶电化学实验上提供了重要帮助。已毕业博士生易骏在理论计算方面提供了有力支持。Underpotential deposition offers a predominant way to tailor the electronic structure of the catalytic surface at the atomic level, which is key to engineering materials with a high activity for (electro)catalysis. However, it remains challenging to precisely control and directly probe the underpotential deposition of a (sub)monolayer of atoms on nanoparticle surfaces. In this work, we in situ observe silver electrodeposited on gold nanocrystals surface from submonolayer to one monolayer by designing a highly sensitive electrochemical dark field scattering setup. The spectral variation is used to reconstruct the optical “cyclic voltammogram” of every single nanocrystal for understanding the underpotential deposition process on nanocrystals, which cannot be achieved by any other methods but are essential for creating novel nanomaterials.The authors thank Dr. Hai-Xin Lin for helpful discussion of nanoparticle synthesis and characterization. The authors acknowledge support from the Natural Science Foundation of China (21633005, 21790354, and 21711530704) and the Ministry of Science and Technology of China (2016YFA0200601).该研究工作得到了国家自然科学基金委和科技部等的资助和支持

ZnO-Based Ultraviolet Photodetectors

Ultraviolet (UV) photodetection has drawn a great deal of attention in recent years due to a wide range of civil and military applications. Because of its wide band gap, low cost, strong radiation hardness and high chemical stability, ZnO are regarded as one of the most promising candidates for UV photodetectors. Additionally, doping in ZnO with Mg elements can adjust the bandgap largely and make it feasible to prepare UV photodetectors with different cut-off wavelengths. ZnO-based photoconductors, Schottky photodiodes, metal–semiconductor–metal photodiodes and p–n junction photodetectors have been developed. In this work, it mainly focuses on the ZnO and ZnMgO films photodetectors. We analyze the performance of ZnO-based photodetectors, discussing recent achievements, and comparing the characteristics of the various photodetector structures developed to date