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Effect of senna obtusifolia(L.)invasion on herbaceous vegetation and soil properties of rangelands in the western Tigray,northern Ethiopia

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Ecological Processes 2018年第1期7卷 81-92页

作者： Maru G.Gebrekiros Zewdu K.Tessema Humera Agricultural Research Center Tigray Agricultural Research InstitutePO Box 492MekelleTigrayEthiopia Rangeland Ecology and Biodiversity Program School of Animal and Range SciencesCollege of Agriculture and Environmental SciencesHaramaya UniversityPO Box 138Dire DawaEthiopia

Introduction:Invasion of exotic plant species is a well-known threat to native ecosystems since it directly affects native plant communities by altering their composition and ***,exotic plant species displace native species through competition,changes in ecosystem processes,or allelopathic *** obtusifolia(L.)invasion has affected the growth and productivity of herbaceous vegetation in semi-arid regions of northern ***,we investigated the species composition,species diversity,aboveground biomass,and basal cover of herbaceous vegetation,as well as soil properties of rangelands along three *** invasion ***:Herbaceous vegetation and soil properties were studied at two locations,Kafta Humera and Tsegede districts,in the western Tigray region of northern Ethiopia under three levels of *** invasion,i.e.,non-invaded,lightly invaded,and heavily *** plant species composition and their abundance were assessed using a 1-m^(2) quadrat during the flowering stage of most herbaceous species from mid-August to September *** species were classified into different functional groups and palatability classes,which can be useful in understanding mechanisms underlying the differential responses of native plants to *** percentage of basal cover for *** and native species and that of bare ground were estimated in each *** to sampling of the herbaceous species,soil samples at a depth of 0–20 cm were taken for analyzing soil physical and chemical ***:Highly palatable grasses and legumes based on the frequency of occurrence were 1.9 and 3.8 times higher in non-invaded sites than in lightly and heavily invaded sites,***,unpalatable plant species were 4.0 times higher in the heavily invaded sites than in the lightly invaded *** biomass,basal cover,and species diversity of the herbaceous vegetation were significantly(P<0.01)lower

关键词： Aboveground biomass Basal cover Invasion level Palatability Species composition Species diversity

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Purification and characterization of a novel cholesterol-lowering protein from the seeds of senna obtusifolia

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Science China(Life Sciences) 2008年第11期51卷 1020-1024页

作者： LI ChuHua1, LI Mei2, CHANG WenRui2 & GUO BaoJiang1 1 College of Life Sciences, South China Normal University, Guangdong Provincial Key Lab of Biotechnology of Plant Development, Guang-zhou 510631, China 2 Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China College of Life Sciences South China Normal University Guangdong Provincial Key Lab of Biotechnology of Plant Development Guangzhou China Institute of Biophysics Chinese Academy of Sciences Beijing China

"Juemingzi", a source of traditional Chinese herbal medicine, has been demonstrated to play a role in decreasing serum cholesterol concentration. In this study, a novel protein, which has shown an in-hibitory effect on cholesterol biosynthesis, was isolated from senna obtusifolia L. seed by gel filtration and ion exchange chromatography. The novel protein’s molecular mass was 19.7 kD and its pI was 4.80. Both SDS-PAGE and isoelectric-focusing (IEF) revealed a single Coomassie brilliant blue stained band, indicating that the novel protein was a single peptide. The N-terminal amino acid sequence of the pro-tein was IPYISASFPLNIEFLPSE, which had no similarity with any other protein sequences in the NCBI protein database. Circular dichroism (CD) signals indicated that S. obtusifolia seed protein contained 12.5% α-helix, 55.6% β-sheet, and 31.9% random coil.

关键词： senna obtusifolia L. seed novel protein purification biochemical properties cholesterol biosynthesis

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Nutritional Potential of Two Leafy Vegetables <i>Leptadenia hastata</i>Decne and <i>senna obtusifolia</i>Link Consumed in Senegal

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Food and Nutrition Sciences 2018年第2期9卷 77-85页

作者： Nicolas Cyrille Ayessou Mady Cissé Mathieu Gueye Cheikh Ndiaye Codou Mar Diop 1Laboratoire d’Electrochimie et des Procédés Membranaires Centre d’Etudes sur la Sécurité Alimentaire et les Molécules Fonctionnelles-Ecole Supérieure Polytechnique Université Cheikh Anta Diop Dakar Senegal Laboratoire d’Electrochimie et des Procédés Membranaires Centre d’Etudes sur la Sécurité Alimentaire et les Molécules Fonctionnelles-Ecole Supérieure Polytechnique Université Cheikh Anta Diop Dakar Senegal Institut Fondamental d’Afrique Noire Cheikh Anta Diop Département de Botanique et Géologie Université Cheikh Anta Diop Dakar Senegal Laboratoire des Biotoxines et Contrô le des Aliments Institut de Technologie Alimentaire (ITA) Route des Pères Maristes Dakar Senegal

This study focused on two woody leafy vegetables Leptadenia hastata Decne and senna obtusifolia Link, commonly consumed in Senegal. Leaves were col-lected from three regions. Then, proximate analyses and micronutrients were carried out to evaluate their nutritional values. Results revealed that protein level of S. obtusifolia (SO) is richer (21.75%) than Leptadenia hastata (LH) (18.16%). The cellulose and carbohydrate contents of the two vegetable’s leaves are in the same order except those of LH from Widou which are less rich in cellulose (8.31%) and richest in carbohydrate (6.35%). These leaves are also good sources of various mineral elements and especially iron. Leaves of LH appear to be richer in iron and magnesium, while SO appears to be richer in calcium. Vitamin C intakes of SO leaves are better than those of LH and respectively range from 142 to 196.5 and 22.5 to 159.5 mg/100 g. According to the use of this leafy vegetable by the populations, a domestication opportunity is thus justified to ensure availability and accessibility of these significant sources of micronutrients.

关键词： Leptadenia hastata senna obtusifolia Woody Leafy Vegetables Nutritional Values Domestication

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Tsinghua Science and Technology

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Tsinghua Science and Technology

作者：孙家广

出版社：清华大学

Tsinghua Science and Technology创刊于1996年，国内外公开发行。主要刊登国内外的理工科基础理论研究与实验研究论文，及时反映学术上有特色、代表学科前沿、当前国际上科学界关心的科技研究成果，推动学术交流，促进研究成果的商品...

Tsinghua Science and Technology创刊于1996年，国内外公开发行。主要刊登国内外的理工科基础理论研究与实验研究论文，及时反映学术上有特色、代表学科前沿、当前国际上科学界关心的科技研究成果，推动学术交流，促进研究成果的商品化和产业化，发挥科学。

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Acta Mechanica Sinica

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Acta Mechanica Sinica

作者： Xiaojin Zheng Xuesong Wu Zhigang Suo

出版社：中国理论与应用力学学会

本刊涵盖了理论和应用力学领域的所有学科，包括固体力学、流体力学、动力学和控制以及生物力学。它探讨了力学所有领域的分析、计算和实验进展。该杂志还鼓励跨学科研究，并充当力学与其他工程和科学分支之间的桥梁。

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Visible-light-responsive homologous heterostructure of oxynitrides constructed to boost charge separation and water splitting

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Science China Chemistry 2025年第1期68卷 186-191页

作者： Hai Zou Yunfeng Bao Xueshang Xin Yu Qi Tengfeng Xie Fuxiang Zhang State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences School of Chemistry and Chemical Engineering Liaoning Normal University College of Chemistry Jilin University

Constructing type II heterostructures represents a widely recognized strategy for enhancing charge separation and photocatalytic efficiency,but it remains challenging to fabricate homologous heterostructures based on visible-light-responsive semiconductors,especially for popularly investigated （oxy）nitrides with low thermal ***,we synthesized a homologous heterostructure （denoted as YTON＿H） based on the oxynitrides of YTaO4-xNyand YTa *** heterostructure exhibits type II band structure alignment and intimate interface achieved through a magnesium （Mg） powder-assisted nitridation *** with widely reported heterologous heterostructures,the as-obtained YTON＿H homologous heterostructure could similarly exhibit enhanced charge separation as well as photocatalytic water splitting performance with respect to its counterparts(YTaO4-xNyand YTaON2).Meanwhile,detailed structural characterizations and spectroscopy analysis have been made to confirm the formation of heterostructure and promotion of spatial charge separation.

关键词： charge separation heterostructure oxynitride photocatalysis visible light

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Cobalamin-dependent radical S-adenosyl-L-methionine protein functions with a partner to successively methylate tricyclic indole alkaloid for chuangxinmycin maturation and derivatization

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Science China Chemistry 2025年第1期68卷 308-316页

作者： Sili Wang Jiancheng Huang Yanan Du Wei Huang Yufeng Xue Xiaokun Xu Guannan Zhong Yuanyuan Shi Bin Hong Xiaoying Bian Wen Liu State Key Laboratory of Chemical Biology Shanghai Institute of Organic Chemistry University of Chinese Academy of SciencesChinese Academy of Sciences State Key Laboratory of Microbial Technology Shandong University National Health Commission (NHC) Key Laboratory of Biotechnology for Microbial Drugs Institute of Medicinal BiotechnologyChinese Academy of Medical Science & Peking Union Medical College

Cobalamin(Cbl)-dependent radical S-adenosyl-L-methionine(SAM) proteins constitute the largest collection of the radical SAM superfamily that has hundreds of thousands of individual members. Many of these proteins are involved in the biosynthesis of pharmaceutically important natural products to catalyze chemically demanding reactions. In the biosynthetic pathway of chuangxinmycin(CXM), a unique indole alkaloid antibiotic with potent anti-infective activity, functionalization of the characteristic thiopyrano[4,3,2-cd]indole scaffold by regio-and stereoselective C3-methylation is believed to rely on a Cbl-dependent radical process, which, however, remained to be reconstituted biochemically. We here report the dissection of this enzymatic process, which requires the incorporation of Cxm8, a Cbl-dependent radical SAM protein, with Cxm9, a DUF5825family protein that shares no homology to any proteins of known functions. Cxm8 and Cxm9 function together by forming an unexpected heterodimeric complex that selectively catalyzes C3-methylation of the tricyclic indole-S-hetero ring system in a successive manner, achieving CXM and a recently identified, C3-dimethylated congener. Detailed biochemical characterization,isotope labeling, structural simulation and bioinformatics analysis rationalized the catalysis of the Cxm8/Cxm9 complex and particularly the necessity of the DUF5825 protein for C3-methylase activity. This is the first example that a Cbl-dependent protein acts with a partner to exhibit radical SAM activity.

关键词： cbl-dependent radical SAM protein biosynthesis chuangxinmycin stereoselective methylation

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Impact of Startup Strategy and Buffer Tank Volume on the Compressor Inlet State for a 3-MW sCO2 Brayton Cycle

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Journal of Thermal Science 2025年第1期34卷 159-175页

作者： ZHAO Decai WANG Bo Key Laboratory of Advanced Energy and Power Institute of Engineering Thermophysics(IET)Chinese Academy of Sciences (CAS) University of Chinese Academy of Sciences

The supercritical carbon dioxide（sCO2） Brayton cycle system has become an emerging and highly promising method of thermal power conversion due to its efficiency advantage,system compactness,and excellent adaptability of the heat *** the low carbon sCO2Brayton cycle testbed with cycle output power approaching 3 MW,a relatively detailed dynamic simulation model of the entire system is constructed to explore the dynamic response characteristics of the system with different startup strategies and different buffer tank volumes during the startup *** simulation results indicate that the smaller the volume of the buffer tank,the more rapid and obvious the parameter fluctuation in the buffer tank during the *** the allowable relative deviation limit of density is 5%,then the ratio of the buffer tank volume to the volume of the entire closed loop should not be lower than 36.80%.The strategy of simultaneous temperature and speed increase during turbine bypass start can effectively reduce the fluctuation of compressor inlet parameters and reach the steady-state more *** paper provides the recommended matching table for the opening of the turbine bypass valve（TBV） and the main regulating valve（MGV） to reduce the parameter fluctuation during the bypass *** effectiveness of the proposed turbine bypass and bypass switching startup strategy is verified by simulation,which may be used as a reference for test bench's future debugging and operation.

关键词： buffer tank dynamic characteristic dynamic model sCO2 Brayton cycle startup strategy

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Trinuclear gold-catalyzed site-selective alkylation of peptides

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Science China Chemistry 2025年第1期68卷 249-256页

作者： Qing-Yun Fang Chengyihan Gu Yinghan Chen Wencheng Yan Yong Liang Weipeng Li Chengjian Zhu Jie Han Jin Xie State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic Materials Chemistry and Biomedicine Innovation Center (Chem BIC) School of Chemistry and Chemical Engineering Nanjing University Green Catalysis Center College of Chemistry Zhengzhou University State Key Laboratory of Natural Medicines China Pharmaceutical University

Selective modification of peptides has always been a challenging issue. The selective alkylation of peptides can alter the biological activity and physical properties of molecules, and it has gained significant research interest. We herein disclose an intriguing gold-catalyzed alkylation of peptides using bench-stable unactivated alkyl bromides under photoredox catalysis. A wide range of structurally diverse primary, secondary and tertiary alkyl bromides serve as effective coupling partners to precisely connect with the α-C(sp3)–H in glycine residue of peptides. This protocol demonstrates an exceptionally broad scope for alkyl halides and excellent tolerance for a wide range of useful functional groups. A series of relay transformations to construct cyclic peptides, to proceed click reaction and to realize peptide fluorescence labeling further enhance its synthetic practicality. In addition, mechanistic studies and density functional theory(DFT) calculations reveal an inner-sphere and subsequent outersphere single electron transfer(SET) mechanism.

关键词： gold catalysis peptide alkylation C-C coupling radical

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Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第1期68卷 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei Xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

关键词： metabolon Diels-Alder reaction semipinacol rearrangement biosynthesis notoamides spiro polycyclic alkaloids

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