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无机化学四个易混淆基本概念的讲授建议 被引量:1
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作者 赵修毅 张伟雄 +1 位作者 刘俊良 乔正平 《大学化学》 CAS 2020年第8期98-102,共5页
化学概念模糊表述容易导致学生学习障碍,不利于培养学生严密的逻辑思维。无机化学是化学及近化学专业的基础课之一,教授对象多为大学一年级本科生,清晰讲授基本概念的重要性不言而喻。本文通过对无机化学四个常见易混淆的概念进行分析,... 化学概念模糊表述容易导致学生学习障碍,不利于培养学生严密的逻辑思维。无机化学是化学及近化学专业的基础课之一,教授对象多为大学一年级本科生,清晰讲授基本概念的重要性不言而喻。本文通过对无机化学四个常见易混淆的概念进行分析,指出了产生错误结论的原因,并给予了一些讲授建议。 展开更多
关键词 热力学 氢键 镧系收缩
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Chromosome-scale genomes of Quercus sichourensis and Quercus rex provide insights into the evolution and adaptation of Fagaceae
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作者 Xue Liu weixiong zhang +5 位作者 Yongting zhang Jing Yang Peng Zeng Zunzhe Tian Weibang Sun Jing Cai 《Journal of Genetics and Genomics》 SCIE CAS CSCD 2024年第5期554-565,共12页
The Fagaceae,a plant family with a wide distribution and diverse adaptability,has garnered significant interest as a subject of study in plant speciation and adaptation.Meanwhile,certain Fagaceae species are regarded ... The Fagaceae,a plant family with a wide distribution and diverse adaptability,has garnered significant interest as a subject of study in plant speciation and adaptation.Meanwhile,certain Fagaceae species are regarded as highly valuable wood resources due to the exceptional quality of their wood.In this study,we present two high-quality,chromosome-scale genome sequences for Quercus sichourensis(848.75 Mb)and Quercus rex(883.46 Mb).Comparative genomics analysis reveals that the difference in the number of plant disease resistance genes and the nonsynonymous and synonymous substitution ratio(Ka/Ks)of protein-coding genes among Fagaceae species are related to different environmental adaptations.Interestingly,most genes related to starch synthesis in the investigated Quercoideae species are located on a single chromosome,as compared to the outgroup species,Fagus sylvatica.Furthermore,resequencing and population analysis of Q.sichourensis and Q.rex reveal that Q.sichourensis has lower genetic diversity and higher deleterious mutations compared to Q.rex.The high-quality,chromosome-level genomes and the population genomic analysis of the critically endangered Q.sichourensis and Q.rex will provide an invaluable resource as well as insights for future study in these two species,even the genus Quercus,to facilitate their conservation. 展开更多
关键词 ADAPTATION Quercus sichourensis Quercusrex Chromosome-scale genome assembly Tandem duplication genes Extremely small populations
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Ferroelastic phase transitions in three new layered perovskites:(3-XC_(6)H_(5)CH_(2)CH_(2)NH_(3))_(2)[CdCl_(4)](X=F,Cl,and Br) 被引量:1
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作者 Yaping Gong Xiaoxian Chen +3 位作者 Bingqing Zhao Jun Wang weixiong zhang Xiaomin Chen 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第12期470-475,共6页
Two-dimensional organic-inorganic hybrid ferroelastics with high-temperature reversible phase transitions are very rare and have become one of the research hotspots in the field of ferroelastic materials.Herein,we rep... Two-dimensional organic-inorganic hybrid ferroelastics with high-temperature reversible phase transitions are very rare and have become one of the research hotspots in the field of ferroelastic materials.Herein,we report three new layered organic-inorganic hybrid perovskites based on halogen-substituted phenethylaminium,(3-XC_(6)H_(5)CH_(2)CH_(2)NH_(3))_(2)[CdCl_(4)](X=F(1),CI(2)and Br(3)).They undergo structural phase transitions at 376/371 K,436/430 K,and 421/411 K,respectively,between the isomorphic hightemperature phases(space group I4/mmm,Z=2)and different room-temperature phases with the reduced structural symmetries,i.e.,P21/a(Z=2)in 1,Pi(Z=4)in 2,and P21/a(Z=4)in 3,respectively.These ferroelastic transitions arise from the order-disorder transition of organic cations together with the synchronous displacement of inorganic layers,accompanying with feroelastic spontaneous strains of 0.16,0.13 and 0.12 for 1-3,respectively.By enriching layered perovskite ferroelastics based on halogensubstituted cations,this work provides important clues for exploring new ferroic materials based on hybrid crystals. 展开更多
关键词 Layered perovskite Phase transition Halogen-substituted FERROELASTIC Spontaneous strain
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Bacillus cereus AR156 primes induced systemic resistance by suppressing miR825/825 and activating defense-related genes in Arabidopsis 被引量:6
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作者 Dongdong Niu Jing Xia +7 位作者 Chunhao Jiang Beibei Qi Xiaoyu Ling Siyuan Lin weixiong zhang Jianhua Guo Hailing Jin Hongwei Zhao 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2016年第4期426-439,共14页
Small RNAs play an important role in plant immune responses. However, their regulatory function in induced systemic resistance(ISR) is nascent. Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that i... Small RNAs play an important role in plant immune responses. However, their regulatory function in induced systemic resistance(ISR) is nascent. Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that induces ISR in Arabidopsis against bacterial infection. Here,by comparing small RNA profiles of Pseudomonas syringae pv. tomato(Pst) DC3000-infected Arabidopsis with and without AR156 pretreatment, we identified a group of Arabidopsis micro RNAs(mi RNAs) that are differentially regulated by AR156 pretreatment. mi R825 and mi R825 are two mi RNA generated from a single mi RNA gene.Northern blot analysis indicated that they were significantly downregulated in Pst DC3000-infected plants pretreated with AR156, in contrast to the plants without AR156 pretreatment. mi R825 targets two ubiquitin-protein ligases,while mi R825 targets toll-interleukin-like receptor(TIR)-nucleotide binding site(NBS) and leucine-rich repeat(LRR)type resistance(R) genes. The expression of these target genes negatively correlated with the expression of mi R825 and mi R825. Moreover, transgenic plants showing reduced expression of mi R825 and mi R825 displayed enhanced resistance to Pst DC3000 infection, whereas transgenic plants overexpressing mi R825 and mi R825 were more susceptible. Taken together, our data indicates that Bacillus cereus AR156 pretreatment primes ISR to Pst infection by suppressing mi R825 and mi R825 and activating the defense related genes they targeted. 展开更多
关键词 Induced systemic resistance ISR micro RNA plant innate immunity small RNA
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The origin and evolution of the diosgenin biosynthetic pathway in yam 被引量:3
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作者 Jian Cheng Jing Chen +9 位作者 Xiaonan Liu Xiangchen Li weixiong zhang Zhubo Dai Lina Lu Xiang Zhou Jing Cai Xueli zhang Huifeng Jiang Yanhe Ma 《Plant Communications》 2021年第1期45-53,共9页
Diosgenin,mainly produced by Dioscorea species,is a traditional precursor of most hormonal drugs in the pharmaceutical industry.The mechanisms that underlie the origin and evolution of diosgenin biosynthesis in plants... Diosgenin,mainly produced by Dioscorea species,is a traditional precursor of most hormonal drugs in the pharmaceutical industry.The mechanisms that underlie the origin and evolution of diosgenin biosynthesis in plants remain unclear.After sequencing the whole genome of Dioscorea zingiberensis,we revealed the evolutionary trajectory of the diosgenin biosynthetic pathway in Dioscorea and demonstrated the de novo biosynthesis of diosgenin in a yeast cell factory.First,we found that P450 gene duplication and neofunctionalization,driven by positive selection,played important roles in the origin of the diosgenin biosynthetic pathway.Subsequently,we found that the enrichment of diosgenin in the yam lineage was regulated by CpG islands,which evolved to regulate gene expression in the diosgenin pathway and balance the carbon flux between the biosynthesis of diosgenin and starch.Finally,by integrating genes fromplants,animals,and yeast,weheterologously synthesized diosgenin to 10mg/l in genetically-engineered yeast.Our study not only reveals the origin and evolutionary mechanisms of the diosgenin biosynthetic pathway in Dioscorea,but also introduces an alternative approach for the production of diosgenin through synthetic biology. 展开更多
关键词 metabolic engineering genomic evolution DIOSGENIN synthetic biology
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