An efficient method for constructing a random insertional mutant library for forward genetics in Nannochloropsis oceanica

Insertional mutation,phenotypic evaluation,and mutated gene cloning are widely used to clone genes from scratch.Exogenous genes can be integrated into the genome during non-homologous end joining(NHEJ)of the double-strand breaks of DNA,causing insertional mutation.The random insertional mutant library constructed using this method has become a method of forward genetics for gene cloning.However,the establishment of a random insertional mutant library requires a high transformation efficiency of exogenous genes.Many microalgal species show a low transformation efficiency,making constructing random insertional mutant libraries difficult.In this study,we established a highly efficient transformation method for constructing a random insertional mutant library of Nannochloropsis oceanica,and tentatively tried to isolate its genes to prove the feasibility of the method.A gene that may control the growth rate and cell size was identified.This method will facilitate the genetic studies of N.oceanica,which should also be a reference for other microalgal species.

FeCo alloy/N,S dual-doped carbon composite as a high-performance bifunctional catalyst in an advanced rechargeable zinc-air battery

The rational design and development of cost-effective,high-performance,and stable bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalysts are essential for rechargeable zinc-air batteries.Herein,a novel FeCo composite composed of alloy nanoparticles embedded in an N,S dual-doped carbon matrix(FeCo/NSC)was prepared via one-step carbonization of amphiphilic dodecanethiol-metal salts wrapped in carbon nitride(C_(3)N_(4)).The compact combination of dual metalalloys and dual-doped carbon endowed the composite with the active sites for the ORR and OER,achieving efficient electrical transmission and highly efficient bifunctional catalytic performance.The obtained FeCo-1/NSC catalyst exhibited excellent electrocatalytic activity with a half-wave potential of 0.82 V(vs.RHE)for the ORR and a low overpotential of 0.325 V at 10 mA cm^(-2) for the OER.The liquid Zn-air battery with FeCo-1/NSC as an air electrode displayed excellent charge-discharge performance,high power density,and robust charge-discharge stability for 150 h compared to the 20%Pt/C+RuO_(2) counterpart.Furthermore,the FeCo-1/NSC-based flexible solid-state Zn-air battery exhibited a higher power density and good charge-discharge stability over 10 h of operation.Thus,a promising strategy for bifunctional electrocatalyst development as part of rechargeable and wearable Zn-air batteries was provided.

Identification of α7 nicotinic acetylcholine receptor on hippocampal astrocytes cultured in vitro and its role on inflammatory mediator secretion

The present study found expressions of a7 nicotinic acetylcholine receptor on hippocampal slices and hippocampal astrocytes using double immunofluorescence stainings. Expression of glial fibdllary acidic protein in the cultured hippocampal slices and hippocampal astrocytes significantly increased, and levels of macrophage inflammatory protein la, RANTES, interleukin-1β, intedeukin-6, and tumor necrosis factor-α increased in the supernatant of cultured astrocytes following exposure to 200 nM amyloid 13 protein 1-42. Preconditioning of 10 μM nicotine, a nicotinic acetylcholine receptor agonist, could attenuate the influence of amyloid β protein 1-42 in inflammatory mediator secretion of cultured astrocytes. Experimental findings indicated that α7 nicotinic acetylcholine receptor was expressed on the surface of hippocampal astrocytes, and activated a7 nicotinic acetylcholine receptor was shown to inhibit inflammation induced by amyloid β protein 1-42.

Rapid and sensitive method for determining free amino acids in plant tissue by high-performance liquid chromatography with fluorescence detection

This paper describes a reliable and rapid method for the complete separation and quantitation of twenty-five amino acids typically found in plants, based on reversed phase high-performance liquid chromatography–linked fluorescence detector using a 150×4.6 mm Zorbax Eclipse AAA column. Plant tissue free amino acids(FAA)were extracted by ultrasonication with 5%(v/v) aqueous trifluoroacetic acid followed by ultrafiltration of extracts.The following analysis of amino acids was performed through programmed precolumn derivatization with orthophthalaldehyde and 9-fluorenylmethyl chloroformate reagents and efficient elution of derivatives within 26 min using binary gradient scheme. The method was validated over a concentration range of 4.5–450 μmol L^(-1)(μM).Separation analysis showed good selectivity(resolution>1.5) for most amino acids. The average repeatability(RSD%, relative standard deviation) of the analysis at seven calibration concentrations was below 4% and ranged from 1.13% to 12.04%. The intra-day mean coefficient of variation at two concentrations(22.5 and 90 μM) was within 2%, and the intermediate precision was less than 4%. The limits of detection were between 0.012 and 6.68 μM. The coefficients of determination(R2) of the linear calibration curves were from 0.9989 to 0.9999.When the method was applied to plant samples, the FAA recoveries at two spiked levels(25 and 100 μM) ranged from 67.0% to 108.9% with an average of 94.4%, and the precision was 0.26%–12.31% RSD. A specific application combining this method with optimized extraction and interference removal procedures was successfully used to determine the FAA pools in different plant tissues. Finally,a PLS-DA multivariate statistics model was validated for the classification of three plant species according to their FAA profiles.

Adsorption of Reactive Dyes on Activated Carbon Developed from <i>Enteromorpha prolifera</i>

Activated carbon was prepared from Enteromorpha prolifera by zinc chloride activation. The adsorption behaviors of three reactive dyes (Reactive Red 23, Reactive Blue 171 and Reactive Blue 4) onto this biomass activated carbon were investigated in batch systems. The experimental findings showed that the removal efficiencies of three dyes onto activated carbon were maximum at the initial solution pH of 4.5 - 6.0. Thermodynamic studies suggested that adsorption reaction was an endothermic and spontaneous process. Adsorption isotherm of the three dyes obeyed Freundlich isotherm modal. Dye adsorption capacities of activated carbon were 59.88, 71.94 and 131.93 mg·g?1 for RR23, RB171 and RB4 at 27?C, respectively. Second-order kinetic models fitted better to the equilibrium data of three dyes. The adsorption process on activated carbon was mainly controlled by intraparticle diffusion mechanism.

Advances of Allelopathic Autotoxicity in Rehmannia glutinosa L.

Allelopathic autotoxicity occurs when a plant releases toxic chemical substances into the environment which inhibits development and growth of the same plant species.Rehmannia glutinosa L.( R.glutinosa ) is one of the most common traditional Chinese medicines,whose productivity and quality,however,are seriously impacted by consecutive monoculture obstacle.Allelopathic autotoxicity is one reason for consecutive monoculture obstacle.In this paper,we reviewed the categories of allelochemicals,the methods of allelochemicals identification,and the mechanisms of allelopathic autotoxicity,which provides clues for further study of the molecular mechanisms of allelopathic autotoxicity and consecutive monoculture obstacle.

The Study of Fuzzy Line Control for Multiple Intersections

The line control for multiple intersections is a hot spot in the area of transportation. According to the principle of system analysis and coordination, a method about fuzzy line control for multiple intersections is proposed. The system is made of two control units, one is the basic control unit for every single intersection, and the other is used for the function of coordination.

The Research of Supply Chain Management Resource Model

Considering the harder and harder competition among enterprises, this paper puts forward the Resource model of supply chain （RBV） to enhance competitive advantages, then analyses the source of supply chain competitive advantages and introduce the advantage formula. Finally, the rent contribution to supply chain management is explained in detail.

Recent Advances in the Electrochemical Defluorinative Transformations of C-F Bonds

Organic fluorine compounds are ubiquitous and pivotally important organic molecules,yet their activation and transformation have long been a formidable challenge due to the high energy and low reactivity of C-F bonds.Organic electrosynthesis,an environmentally benign synthetic method in organic chemistry,enables a myriad of chemical transformations without the need for external redox reagents.In recent years,organic electrochemistry has emerged as a powerful tool for achieving the activation and transformation of C-F bonds in fluorine-containing compounds.This review aims to succinctly recapitulate the latest advancements in the electrochemical defluorinative transformations of C-F bonds and to delve into the reaction design,mechanistic insights,and developmental prospects ofthese methods.

湖北地黄CRISPR/Cas9基因编辑体系的建立

湖北地黄(Rehmannia henryi)是一种具有重要价值的药用植物,其基因编辑研究还未见报道。为建立湖北地黄基因编辑体系,克隆了类胡萝卜素合成途径中八氢番茄红素脱氢酶(PDS)的编码基因,并构建RhPDS1基因的CRISPR/Cas9载体,以根癌农杆菌介导法转化湖北地黄基因组。结果表明,RhPDS1转录本含1764 bp的开放阅读框(ORF),其推测的氨基酸序列具有八氢番茄红素脱氢酶的典型结构域。RhPDS1基因在蕾、花和嫩叶中的相对表达量较高。利用基因编辑获得3个具有白化表型的再生株系,白化苗分化率为3.7%。测序结果表明,3个突变体属于2个基因编辑事件,靶点序列分别为1 bp或/和5 bp碱基缺失,造成移码突变。白化苗突变体的叶绿素和类胡萝卜素含量极显著低于野生型,RhPDS1基因的表达量也显著下降。综上,该研究克隆了RhPDS1基因,并利用CRISPR/Cas9技术实现了对RhPDS1基因的靶向敲除,为湖北地黄的功能基因组学研究和野生驯化奠定了技术基础。

中心对称且具有非简单空间群结构的晶体中可调控的Dzyaloshinskii-Moriya相互作用

非中心对称材料中存在的Dzyaloshinskii-Moriya(DM)相互作用,可以导致新颖的自旋纹理和奇异的手性物理现象.而如果能在中心对称的晶格中发现DM相互作用,这将可以大大丰富实现上述新奇物理的材料体系.本文发现中心对称的且遵循非简单空间群结构的巡游电子体系可以作为实现DM相互作用的新平台.以遵循P4/nmn空间群的晶格为例,作者展示了在该中心对称晶格中,由巡游电子导致的Ruderman-Kittel-Kasuya-Yosida(RKKY)相互作用中包含DM相互作用、Heisenberg交换相互作用和Kaplan-Shekhtman-Entin-wohlman-Aharony(KSEA)相互作用.在这其中,DM相互作用的DM矢量的方向取决于实空间中磁性原子的位置,DM相互作用的强度取决于动量空间中费米面的位置.该晶格体系中磁性相互作用的多样性,源于非简单空间群对称性保证的实空间中位置依赖的在位点群和倒空间中动量依赖的电子结构.本研究揭示了非简单空间群对称性如何影响晶体中的磁性,表明非简单空间群晶格体系是设计磁性相互作用非常有前景的平台.

中国公众的国际野生动物保护意愿调查:以非洲象为例

我国高度重视野生动物保护事业,认真履行野生动物保护国际义务,积极鼓励公众参与,以扩大野生动物保护事业的公众基础。已有文献多关注了公众的国内野生动物保护意愿,鲜有文献关注公众对国际野生动物的保护意愿,难以为促进公众参与国际野生动物保护事业提供决策参考。本研究以全球旗舰物种非洲象(Loxodonta africana)为例,结合非洲象保护的相关研究与实践,构建拓展的计划行为理论框架,通过线下和线上调研获取数据,运用结构方程模型,从态度、规范、知觉行为控制、过去经验及个体特征五个方面,分析了我国公众的非洲象保护意愿及影响因素。结果表明:(1)68.5%的公众具有非洲象保护愿意;(2)公众规范(系数为0.422)、过去经验(系数为0.253)、知觉行为控制(系数为0.160)、保护态度(系数为0.156)对保护意愿存在显著的正向影响;男性公众(系数为-0.054)的保护意愿低于女性公众;居住在西部地区的公众(系数为0.066)保护意愿更高;(3)模型整体通过了拟合检验,表明研究结果具有稳健性。本研究的政策建议如下:(1)明确政策导向作用,提升公众的道德义务感和社会责任感;(2)加强宣传教育,丰富公众知识经验,培育公众积极的保护态度;(3)拓宽保护参与渠道,提高公众知觉行为控制;(4)制定合理方案,提升保护宣教等实践活动成效。

我国亚洲象保护与农村社区发展协同问题分析

亚洲象保护与农村社区发展的协同共进关系到所在区域能否实现人与自然和谐发展。文中首先基于协同理论分析亚洲象所在区域的社会生态系统特征,建立了亚洲象保护与社区发展的交互作用分析框架;其次,分析亚洲象保护与社区发展的交互作用,得出亚洲象所在区域的社会生态系统存在协同问题;再次,从亚洲象对应的生态子系统,社区对应的社会经济系统、治理子系统,以及外部社会经济治理系统等方面存在的特殊性及不足,分析产生协同问题的原因;最后,提出了加强顶层制度设计、健全组织保障、优化工作机制、创新社区发展模式和加强科研支撑等对策建议。

SHRIMP zircon U-Pb dating of the intrusives in the Tongling metallogenic cluster and its dynamic setting

This paper selected five typical Mesozoic intrusives from the Tongling metallogenic cluster (Xiaotongguanshan, Fenghuangshan, Xinqiao, Dongguashan, and Shatanjiao plutons), and made a systemic SHRIMP zircon U-Pb dating for the five plutons, which produced

Two glucosylated angucyclines from deep-sea-derived Streptomyces sp.PKU-MA01297

Angucyclines are aromatic polyketides produced by typeⅡpolyketide synthase(PKS)exclusively from actinomycetes.These natural products contain hydrolyzable sugar moieties that attach to various positions of the polyketide skeleton and expand the structural diversity.We here report the isolation of two new angucyclines(1 and 2)from the deep-sea-derived Streptomyces sp.PKU-MA01297,which was isolated from a sediment sample collected at a depth of 3202 meters from the Indian Ocean.The structures of the two new compounds were elucidated based on comprehensive methods,including NMR,MS and CD analysis.Compounds 1 and 2 featured a 1-O-β-D-glucopyranosyl moiety that has not been reported for angucyclines.Several biological activity assays,including antibacterial,cytotoxicity and anti-inflammatory assays,were carried out,and compounds 1 and 2 showed no activities.These results set the stage for biosynthetic research and more biological activity assays in the future.

New correlation features for dissolved gas analysis based transformer fault diagnosis based on the maximal information coefficient

Online monitoring of gases dissolved in transformer oil is widely applied.Improving the performance of dissolved gas analysis(DGA)‐based fault diagnosis methods by exploring new features of time‐series data has become an appealing topic.In this study,a new type of correlation features between characteristic gases was extracted from time‐series data based on the maximal information coefficient(MIC),and a fuzzy inference system was established.After the introduction of the principle of the MIC and a method for calculating the MIC‐based correlation features,the dominant symptom features that can be used to classify fault types were extracted through the receiver operating characteristic curve.Then,fuzzy rules were learnt,and a fuzzy inference system was designed.In addition,to improve the feasibility of the method,the Newton interpolation method was used for adaptation to the existing sampling cycle.The diagnostic results of the test data show that the proposed method has excellent per-formance and outperforms some prevailing traditional rule‐based methods as well as some artificial intelligent methods.The results also show that by exploring new cor-relation features from time‐series data based on the MIC,the performance of DGA‐based methods can be improved.

Functional Characterization and Crystal Structure of the Type Ei Peptidyl Carrier Protein ColAia in Collismydns Biosynthesis

Summary of main observation and conclusion Collismycins(COLs)are antibiotics characterized by a 2,2'-bipyridine(2,2'-BP)core composed of a trisubstituted ring A and an unmodified ring B.The 2,2'-BP core,which possesses metal-chelating ability and plays key roles in various biological activities of COLs,is biosynthesized by a nonribosomal peptide synthetase(NRPS)-polyketide synthase(PKS)hybrid machinery.The starter module of the NRPS-PKS hybrid machinery consists of a type II peptidyl carrier protein(PCP)ColA1a and an adenylation protein ColA1b.We here report the functional characterization of ColAia and ColAlb in vitro,confirming their functions in selection and loading of picolinic acid(PA),instead of normal amino acid substrates,as the origin of ring B in COLs.The 2.1 A crystal structure of ColAia was solved,revealing structural features including the additional helices ala,alb and missing helix a3,which may reflect unique interactions of ColAia with other NRPS-PKS proteins/domains or substrate.Primary and tertiary structural comparison of ColAia with other PCPs revealed the structural basis for their typical a-helical bundle,providing a better understanding of the structural flexibility of PCPs.These results facilitate the starter module engineering for the generation of COL derivatives with ring B modifications in the future.

Synthesis of two substrate mimics of thioesterase in the biosynthesis of cyclic depsipeptide WS9326A

WS9326 A is a tachykinin receptor antagonist and quorum sensing inhibitor discovered from several Streptomyces strains.The structure of WS9326 A features a(Z)-pentenylcinnamoyl moiety attached on a cyclic depsipeptide skeleton,which is biosynthesized by nonribosomal peptide synthetases(NRPS).The regioselective cyclization in the last step of NRPS catalysis,which is proposed to be catalyzed by a thioesterase(TE)domain in the last module,has not been experimentally characterized.We here report the synthesis of two substrate mimics(1 and 2)of the TE(WS9326 A-TE)in WS9326 A biosynthesis,by using Fmoc-based solid-phase peptide synthesis(SPPS)method.Compounds 1 and 2 are new compounds whose structures have been elucidated based on NMR and HRESIMS analyses.The N-terminal cinnamoyl moiety and C-terminal methylated L-Ser moiety in 2 were incorporated under the mild SPPS conditions.Given the isolation difficulties of substrate of WS9326 A-TE from the Streptomyces producers of WS9326 A,our synthesis of 1 and 2 set the stage for the reconstitution of WS9326 A-TE’s catalytic reaction in vitro in the future.

Removal of inhalable particles from coal and refuse combustion by agglomeration with solid nuclei

Airborne inhalable particles are a potent environmental pollutant. Formed via industrial processes, separation of these particles is difficult using conventional clean up techniques. In this work, solid nuclei particles of different chemical compositions were introduced into an agglomeration chamber with simulated flue gases to investigate their ability to remove these particles. Organic nuclei were able to capture more inhalable particles from coal-derived fly ash than inorganic nuclei, though these proved more effective for the agglomeration of inhalable particles in refuse-derived fly ash. Increasing the diameter of the solid nuclei benefitted the agglomeration process for both types of ash. Varying the local humidity changed adhesion between the particles and encouraged them to aggregate. Increasing the relative humidity consistently increased particle agglomeration for the refuse-derived ash. For coal-derived fly ash, the removal efficiency increased initially with relative humidity but then further increases in humidity had no impact on the relatively high efficiencies. After agglomeration in an atmosphere of 62% relative humidity, the mean mass diameter of inhalable particles in the coal-derived fly ash increased from 3.3 to 9.2 μm. For refuse-derived fly ash, agglomeration caused the percentage of particles that were less than 2μm to decrease from 40% to 15%. After treatment at a relative humidity of 61%, the mean size of inhalable particles exceeded 10 μm.

The current application of thermal ablation in colorectal liver metastasis

Colorectal liver metastases(CRLM)are one of the most frequent clinical conditions.Over the last 20 years,the clinical outcome for patients with CRLM has improved greatly.Liver resection is the gold standard treatment for resectable CRLM,achieving a 5-year overall survival(OS)rate of 42%(1).However,the majority of patients with CRLM are not candidates for resection.With the development of thermal ablation,this technique provides an alternative treatment modality by either ablation alone or combined with resection.A recent review by Takahashi et al.summarized the current role of thermal ablation in the management of CRLM(2).