Manganese toxicity-induced chlorosis in sugarcane seedlings involves inhibition of chlorophyll biosynthesis

Manganese(Mn)toxicity-induced leaf chlorosis limits crop production in acidic soils,but its underlying mechanisms remain unknown.The effects of excessive Mn on chlorophyll(Chl)biosynthesis in sugarcane(Saccharum officinarum L.)leaves were investigated.Under Mn treatment,Chl concentration decreased with Mn accumulation and chlorosis appeared in expanding leaves.Before that,levels of the initial Chl precursor 5-aminolevulinic acid(ALA)and its downstream intermediates decreased,whereas magnesium-protoporphyrin IX monomethyl ester(MgPME)accumulated.Overaccumulation of Mn in leaves downregulated the ALA biosynthetic gene GluTR(encoding glutamyl-tRNA reductase)and MgPME conversion gene MgPMEC(encoding MgPME cyclase),upregulated the ALA biosynthesis inhibitor FLU(encoding FLUORESCENT),but had no significant effect on the expression of other Chl biosynthetic genes.The above Mn-induced changes of Chl precursors and expression of corresponding genes commenced before the Chl decline and leaf chlorosis,and were reversed by ALA supplementation.Thus,excessive Mn-induced chlorosis in sugarcane is mediated by a Chl-biosynthesis disorder resulting from the inhibition of ALA synthesis and MgPME conversion.

CuO/Co_(3)O_(4)Bifunctional Catalysts for Electrocatalytic 5-Hydroxymethylfurfural Oxidation Coupled Cathodic Ammonia Production

The electrochemical coupling of biomass oxidation and nitrogen conversion presents a potential strategy for high value-added chemicals and nitrogen cycling.Herein,in this work,CuO/Co_(3)O_(4)with heterogeneous interface is successfully constructed as a bifunctional catalyst for the electrooxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid and the electroreduction of nitrate to ammonia(NH_(3)).The open-circuit potential spontaneous experiment shows that more 5-hydroxymethylfurfural molecules are adsorbed in the Helmholtz layer of the CuO/Co_(3)O_(4)composite,which certifies that the CuO/Co_(3)O_(4)heterostructure is conducive to the kinetic adsorption of 5-hydroxymethylfurfural.In situ electrochemical impedance spectroscopy further shows that CuO/Co_(3)O_(4)has faster reaction kinetics and lower reaction potential in oxygen evolution reaction and 5-hydroxymethylfurfural electrocatalytic oxidation.Moreover,CuO/Co_(3)O_(4)also has a good reduction effect on NO_(3)^(-).The ex-situ Raman spectroscopy shows that under the reduction potential,the metal oxide is reduced,and the generated Cu_(2)O can be used as a new active site for the reaction to promote the electrocatalytic conversion of NO_(3)^(-)to NH_(3) synthesis.This work provides valuable guidance for the synthesis of value-added chemicals by 5-hydroxymethylfurfural electrocatalytic oxidation coupled with NO_(3)^(-)while efficiently producing NH_(3).

磁性花生壳生物碳的制备及其吸附性能综合实验设计

利用不同生物质为原料,热解法制备出生物碳,对比选出花生壳生物碳,并在其表面负载Fe3O4磁性材料处理水中四环素。采用扫描电子显微镜(SEM)、比表面积分析仪(BET)、X射线衍射仪(XRD)等手段表征了磁性花生壳生物碳特征,并研究了吸附动力学、等温线特性以及各种影响去除效果的因素。通过此综合实验,使学生建立"以废治废"理念,并掌握用废弃物制备吸附剂的方法、材料表征技术和污染物的调控方法。此外,注重理论与实际结合,提高学生的创新意识达到学以致用的目的。

Research on Electromagnetic Acoustic Emission Signal Recognition Based on Local Mean Decomposition and Least Squares Support Vector Machine

Electromagnetic acoustic emission technology is one of nondestructive testing, which can be used for defect detection of metal specimens. In this study, round and cracked metal specimens, round metal specimens, and intact metal specimens were prepared. And the electromagnetic acoustic emission signals of the three specimens were collected. In addition, the local mean decomposition(LMD), Autoregressive model(AR model) and least squares support vector machine (LSSVM) algorithms were combined to identify the eletromagnetic acoustic emission signals of round and cracked, round, and intact specimens. According to the algorithm recognition results, the recognition accuracy of can reach above 97.5%, which has a higher recognition rate compared with SVM and BP neural network. The results of the study show that the algorithm is able to identify quickly and accurately crack defect in metal specimens.

Inhibition of lipid oxidation in foods and feeds and hydroxyl radical-treated fish erythrocytes:A comparative study of Ginkgo biloba leaves extracts and synthetic antioxidants

This study explored the effects of butylated hydroxytoluene(BHT) and ethoxyquin(EQ) and ethyl ether extracts, ethyl acetate extracts(EAE), acetone extracts, ethanol extracts and aqueous extracts of Ginkgo biloba leaves(EGbs) on lipid oxidation in a linoleic acid emulsion, fish flesh and fish feed and in hydroxyl radical(·OH)-treated carp erythrocytes. The linoleic acid, fish flesh and fish feed were incubated with BHT,EQ and EGbs at 45℃ for 8 d, respectively, except for the control group. The lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed was then measured by the ferric thiocyanate method or thiobarbituric acid method. The carp erythrocytes were treated with BHT, EQ. or EGbs in the presence of40 μmol/L FeSO_4 and 20 μmol/L H_2 O_2 at 37℃ for 6 h,except for the control group. Oxidative stress and apoptosis parameters in carp erythrocytes were then evaluated by the commercial kit. The results showed that BHT, EQ and EGbs inhibited lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed and·OH-induced phosphatidylserine exposure and DNA fragmentation(the biomarkers of apoptosis) in carp erythrocytes. Furthermore, BHT, EQ and EGbs decreased the generation of reactive oxygen species(ROS),inhibited the oxidation of cellular components and restored the activities of enzymatic antioxidants in·OH-treated carp erythrocytes. Of all examined EGbs, EAE showed the strongest effects. The effects of EAE on lipid oxidation in the linoleic acid emulsion and on superoxide anion and malonaldehyde levels,catalase activity and apoptosis in. OH-treated carp erythrocytes were equivalent to or stronger than those of BHT. Moreover, these results indicated that the inhibition order of EGbs on the generation of ROS and oxidation of cellular components in fish erythrocytes approximately agreed with that for the food and feed materials tested above. And, the antioxidative and anti-apoptotic effects of EGbs were positively correlated with their flavonoid content. Taken together, these results revealed that the fish erythrocyte system can be used as an experimental model to evaluate lipid oxidation in food and feed ingredients. The EAE can be used as a potential natural antioxidant or apoptosis inhibitor. The inhibition effects of EGbs on lipid oxidation and apoptosis may be due to the presence of flavonoid compounds.

Exosomal lncRNA LINC01268 promotes pancreatic cancer progression via the miR-217-KIF2A-PI3K/AKT axis

Pancreatic cancer(PaCa)is one of the most aggressive and lethal malignancies with rapid progression and poor prognosis with the 5-year survival rate remaining less than 5%because approximately 80%of PaCa patients are diagnosed at an advanced stage and lose the chance of curative resection.1 Accumulated evidence has revealed that noncoding RNAs(ncRNAs)are involved in the pathogenesis of PaCa and serve as potential biomarkers for PaCa.2,3 Exosomal lncRNAs also play a vital role in tumorigenesis and some exosomal lncRNAs have been reported to accelerate tumor progression.4 In this study,we first employed RNA-seq of PaCa plasma samples to identify significantly differentially expressed lncRNAs in PaCa patients and revealed that LINC01268 was up-regulated in PaCa tumor tissues and plasma.LINC01268 is an emerging lncRNA associated with glioma malignancy grade.5 Thus.we further analyzed the malignant biological behaviors of this lncRNA in PaCa and found that LINC01268 promoted cell proliferation,migration,and invasion as an oncogene,which promoted epithelial–mesenchymal transition(EMT)in PaCa via the miR-217-KIF2A-PI3K/AKT axis.

中国典型草原植被高度组合的普适性规律与区域差异

详细测定每株植物高度是精细评估草地生态系统中植物群落高度结构的重要方法,并经常用来分析草地植被生长与环境因子关系的普适性和区域差异。本研究在我国青藏高原、内蒙古高原和黄土高原,分别沿降水梯度布设了3条从草甸-草原-荒漠的典型草地生态系统样带。研究结果发现,我国3大高原的草地生态系统植被平均高度为30.38±22.44 cm,其中黄土高原最高,内蒙古高原次之,青藏高原最低。这3个高原草地生态系统的植被聚合高度分布都呈现偏正态分布(0.91,3.60),而且从青藏、内蒙古到黄土高原,该分布逐渐趋于正态(0,3)。然而,在青藏高原的草甸和荒漠生态系统中分别呈现出指数分布和均匀分布。在3大高原中,气候和土壤营养对植被平均高度解释率超过70%,然而对植被聚合高度的解释率最高仅为29%(青藏高原)。从青藏高原、内蒙古高原至黄土高原,植被平均高度对环境综合响应强度逐渐增强,具体表现为气温、降水的影响逐渐增强,而辐射、风速和营养物浓度影响逐渐减弱。我们的研究表明,正态分布是草地植被高度构建的普适性原则,而环境因素的协同作用在不同区域存在差异。