钕诱导番茄产生抗性的时间研究

采用盆栽试验研究了Nd3 在不同诱导时间对番茄叶抗性指标(过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性、细胞膜透性、氧自由基(O2-·)产生速率和木质素含量)的影响.结果表明:从第3 d开始,Nd3 诱导提高番茄叶内PAL活性,第3d增幅也最大,达32.30%,维持时间为诱导后第3～5 d;Nd3 诱导后第1～2 d POD活性升高,第1 d增幅最大,维持时间是诱导后第1～2 d;Nd3 诱导后1～3 d,PPO活性升高,第1 d增幅最大,维持时间是诱导后第1～3 d;从诱导后第2 d开始,Nd3 降低细胞膜透性,第3 d时降幅最大,为54.33%,持续时间为诱导后第2～5 d;从第3 d开始,Nd3 诱导降低氧自由基产生速率,第4 d降幅最大,第3 d氧自由基产生速率最低,持续时间为诱导后第3～5 d;从第4 d开始,Nd3 诱导提高木质素含量,5 d时有继续升高的趋势.从不同诱导时间番茄叶PAL活性、细胞膜透性、氧自由基产生速率的变化来看,在Nd3 诱导的第3 d,番茄产生的抗性最强.     

《环境样品中双酚类化合物的固相萃取研究进展》作者勘误

发表在《色谱》2021年第39卷第8期835-844页的《环境样品中双酚类化合物的固相萃取研究进展》一文中,表1第9行第6列TBBPA的log K_ow值应为4.50,特此更正并向读者致歉!     

一氧化碳和甲烷一体化光纤传感测量系统

一氧化碳和甲烷一体化光纤传感测量系统主要包括第一个DFB激光源、第二个DFB激光源、第一个波形发生器、第二个波形发生器、第一个波长选择与调制器、第二个波长选择与调制器、光纤耦合器、传感探头、光电转换模块、信号调理与数据采集模块和微处理器。连接方式如下：第一个波形发生器作用于第一个波长选择与调制器，第一个波长选择与调制器控制第一个DFB激光源，第一个DFB激光源通过光纤连接耦合器的一个输入端；第二个波形发生器作用于第二个波长选择与调制器，第二个波长选择与调制器控制第二个DFB激光源，第二个DFB激光源通过光纤连接耦合器的另一个输入端；耦合器的输出端连接传感探头；传感探头连接光电转换模块；     

《铅酸蓄电池分析与检测技术》

该书在第1章、第2章介绍了与铅酸蓄电池材料相关的化学分析基本理论与基本操作;第3章重点阐述了铅酸蓄电池生产用原材料的分析,如铅与铅合金、隔板、酸水体系、正负极添加剂及槽盖等外壳材料;第4章着重阐述了铅酸蓄电池生     

在实验室里研究不同价态硫元素间的转化

1教学内容分析本课时选自鲁科版必修1第三章第3节"硫的转化"的第2课时。在之前的第1课时学生了解了含硫物质在自然界中转化以及硫单质的性质。本节课在此基础上,引导学生运用氧化还原反应理论探究在实验室实现不同价态硫元素之间的转化。通过     

〈合成化学〉2004年人选美国化学文摘（CA）千种表

《合成化学》曾于1998年入选CA千种表的第803名（中国入选期刊的第53名），2003年再度入选千种表，名列中国入选期刊的第39名（在CA千种表中名列第710名），2004年入选千种表的第1000名（中国入选期刊的第94名）。     

追思敬爱的主编黄葆同先生

我们怀着无比悲痛的心情,沉痛悼念黄葆同先生、深切缅怀他光辉的一生。黄葆同先生是我国著名的高分子化学家、教育家、中国科学院资深院士、杰出的归国华侨、无党派民主人士、全国第六、第七、第八届人大代表、原长春应化所副所长。第四、五、六届《应用化学》期刊主编。黄葆同     

中药柴胡总皂苷急性肝毒性的代谢组学研究

运用UPLC-MS联用技术对空白对照组、柴胡总皂苷(SS)组大鼠在给药后第3天和第5天的尿液样本进行分析检测,获得了以质荷比和保留时间为变量的矩阵数据。据此建立各组大鼠的尿液代谢轮廓图,并利用主成分分析(PCA)建立了SS的代谢组学毒性模型。结合肝组织病理,探讨了柴胡总皂苷的急性肝毒性。对于SS组与正常组,大鼠尿液代谢轮廓图表现出了一定的差异。在代谢组学毒性模型中,给药第3天和第5天的PCA分类均偏离正常组,而第5天的偏离程度强于第3天。同时,在第5天的肝组织病理切片中发现了组织病变。由此表明,给药组大鼠的代谢组偏离了正常组,这种偏离正是肝急性毒性的表现,且给药到第5天的肝毒性强于第3天,表明肝毒性与给药累积剂量呈正相关,表现出了明显的急性和累积肝毒性。     

更正说明

因编辑工作失误,本刊2013年第34卷第5期第828～837页发表的文章"Research,development,and application ofamorphous nickel alloy catalysts prepared by melt-quenching(急冷非晶态镍合金催化剂的研究开发和工业应用)"(作者:宗保宁,慕旭宏,张晓昕,孟祥堃,乔明华)中第829页图1有误,正确的图及图题如下.特此更正并致歉.     

中国化学会1992年学术活动规划

序一号会议名称时间地点人数筹备单位及负责人第五届无机化学学术讨论会第六届大环化学学术讨论会第七届金属有机化学学术报告会第五届天然有机化学学术讨论会第四届原子光谱分析学术报告会第四届有机微量及痕量分析学术 讨论会第一届生物分析化学学术讨论会高分子学术论文报告会高分子材料形变损伤与 破坏学术讨论会第七届反应性高分子(离子交换 与吸附)学术讨论会第七届裂解色谱学术会议第四届特种应用化学学术讨论会第二届防化学术讨论会食品添加剂化学会议建筑防水材料讲习班1992。101992。4天津昆明杭州北京厦门重庆3001501992。112001…     

Molecular Basis for Stereospecific Hydrolysis of Ethyl Mandelate by Thermophilic Esterase

The stereospecific hydrolysis of mandelate can be effectively catalyzed by hyperthermophilic acylpeptide esterase APE 1547(Aeropyrum pernix esterase 1547). APE 1547 used in this reaction showed a remarkable stereodiscrimination in favour of R-mandelic acid(99% e.e.) with an enantiomeric ratio E>200. The results of computer simulation are consistent with the experimental results. It can be inferred that the R-substrate adopted a binding mode productive of the reaction due to the formation of the hydrogen bond at the active site of APE 1547.     

Denaturing Effects of Urea and Guanidine Hydrochloride on Hyperthermophilic Esterase from Aeropyrum pernix K1

Introduction Esterases(EC3.1.1.x)representadiversegroup ofhydrolasescatalyzingthecleavageandformationof esterbonds.Theyarewidelydistributedinanimals,plantsandmicroorganisms.Becauseoftheiractivities inbothaqueousandnonaqueoussolventsystems,ester aseshavebe…     

古细菌Aeropyrum pernix K1超嗜热酯酶APE1547的稳定性

研究了纯化的超嗜热酯酶APE1547的稳定性. 结果表明, 该酶的稳定性非常好, 蛋白的质量浓度为0.4 mg/mL时, 90 ℃的半衰期为20 h, 0.2 mg/mL时的半衰期为12 h; 而蛋白的质量浓度为0.04 mg/mL时, 保温2.5 h时残余活力仍在50%以上. 同时还研究了热变性时该酶表面疏水氨基酸的变化. 该酶的pH稳定性也很好, pH在6.5-9.0范围内作用24 h, 酶依然很稳定, 残余酶活力大于93％; 同时该酶还具有很强的耐有机溶剂的特性.     

Enhanced Activity and Enantioselectivity of a Hyperthermophilic Esterase from Archaeon Aeropyrum pernix K1 by Acetone Treatment

To improve the activity and enantioselectivity of hyperthermophilic archaeon Aeropyrum pernix K1 esterase (APE1547) and its mutants, they were purified by acetone-treated method. It was found that the acetone treatment not only caused APE1547 and its mutants to display higher activity and enantioselectivity but also saved more than 90% of time spent in purifying them by Ni-chelating column. In hydrolysis of p-nitrophenyl caprylate, the acetone-treated APE1547 and mutant A containing the following substitutions R11G, L36P, V225A, I551L, and A564T showed 5.7- and 6.9-fold active increase, respectively. In the resolution of 2-octanol acetate, the acetone-treated mutant A had a 9-fold enantioselective increase relative to that purified by Ni-chelating column. In addition, the impact of pH, temperature, and chemical reagents on activity of APE1547 and mutant A was discussed in this paper.     

Enzyme catalytic promiscuity: asymmetric aldol addition reaction catalyzed by a novel thermophilic esterase in organic solvent

The asymmetric aldol addition of 2-butanone and 4-nitrobenzaldehyde catalyzed by a novel thermophilic esterase (APE1547) from the archaeon Aeropyrum pernix K1 was successfully conducted in organic solvents. APE1547 exhibited a good enzyme activity and enantioselectivity in the reaction. The effects of organic solvent, temperature, water content, and substrate concentration were investigated. The reaction provided optically active secondary alcohol with satisfying enantioselectivity (71.2 %ee) and enzyme activity (38.1 µmol/g/h) under the optimum conditions. A high yield (68.7%) could be obtained when the reaction time was approximately 120 h.     

Acylation of Quercetin with a Novel Thermophilic Esterase as Biocatalyst

The regioselective acylation of quercetin catalyzed by a novel thermophilic esterase(APE1547)from the archaeon Aeropyrum pernix K1 was successfully conducted in organic solvents.The effects of acyl don...     

离子液体中酶促Michael加成反应的研究

以离子液体作为反应介质,研究了嗜热酯酶APE1547在不同离子液体中催化咪唑与丙烯酸乙酯的Mi-clasel加成反应,并对反应条件进行了优化.在最适反应条件下,Michael加成反应产率可达98.8%,另外发现嗜热酯酶APE1547在该反应体系中可重复使用8次,其催化性能没有明显下降.     

Study on a Specific Site Tyr~(444) on a Hyperthermophilic Enzyme APE1547

Hyperthermophilic enzyme APE1547 is an extremely thermostable recombinant protein from thermophilic archaeon Aeropyrum pernix K1. The Tyr444 located in the catalytic domain adjacent to the catalytic amino acid Ser445 and formed hydrogen bond with Ile567. To study the effect of Tyr444 on the activity of APE1547,site-directed mutagenesis was applied. Two mutant enzymes T444S and T444G were created. Comparison of the mutant enzymes with wide enzyme,the thermostability of mutants T444S and T444G decreased by 10...     

DFT Calculations on Hydrogen-Bonded Complexes Formed Between Guanine and Acrylamide

B3LYP/6-311+G* theoretical calculations have been employed to investigate the complexes involving hydrogen bonding between guanine and acrylamide. Nine stable conformers were obtained by geometry optimization without imaginary frequencies. The calculation results revealed that the stability of these complexes was accounted for by the intensity and numbers of hydrogen bonds between guanine and acrylamide, which was proved by the energy analysis and the topological properties at the critical points. In these optimized complexes, the complex with three hydrogen bonds was the most stable one because it offered the biggest binding energy. Clearly, the hydrogen bonds appear to be crucial in the stability of these complexes. This work will provide another nosogenetic interpretation besides the covalent interactions between DNA and acrylamide, which are of interest for studying DNA mutation.     

脲基杯[4]二(9-冠-3)对钠-卤素离子对的识别作用

采用Oniom方法(B3LYP/LANL2DZ∶PM3)对脲基取代的二(9-冠-3)杯[4]芳烃衍生物(H)与离子对Na+X-(X=F-,Cl-,Br-)的包合作用进行了理论研究.在上述体系中存在2种包合方式:一是阴、阳离子在包合物中是分离的,阴离子与主体分子的上沿主要以N—H…X-氢键作用;二是阴、阳离子在包合物中存在明显的离子配对作用,阴离子主要以阳离子的配对作用存在.通过对包合物Na+X-/H的结构参数、自然键轨道(NBO)以及结合能分析可知,第1种包合方式更有利.研究表明脲基取代的二(9-冠-3)杯[4]芳烃衍生物可成为有效的离子对识别受体,研究结果进一步加深了杯芳烃类受体对离子对识别机理的认识,为实验上设计合成新型离子对受体提供了理论依据.