核黄素合成途径关键酶：新型生防制剂筛选靶标

植物和微生物可以自身合成核黄素,动物必须完全从食物中摄取,因此核黄素合成途径中关键酶抑制剂可开发为杀菌剂或除草剂,对人畜安全、无副毒作用.论述了有关核黄素合成途径中抑制作用靶标位点、筛选模型和抑制剂种类的研究进展,探讨了今后研究思路.以催化核黄素合成途径最后3步反应的羟基磷酸丁酮合成酶DHBPS、二氧四氢喋啶合成酶LS和核黄素合成酶RS作为抑制作用靶标位点,离体和活体筛选抑制剂.新筛选靶标和模型的建立有助于开发新型生防制剂.     

2种酰胺类杀菌剂对4种非靶标生物的急性毒性

为评价噻呋酰胺和环酰菌胺对4种非靶标生物的急性毒性,本试验采用饲喂法、浸叶法、半静态法、人工土壤接触法分别测定了2种酰胺类杀菌剂对意大利工蜂、家蚕、斑马鱼、赤子爱胜蚯蚓的急性毒性。结果表明,噻呋酰胺和环酰菌胺对意大利工蜂经口毒性48 h-LD₅₀值分别为6.51和9.12μg/蜂;对家蚕96 h-LC₅₀值分别为375.71和5 802.32 mg/L;对斑马鱼96 h-LC₅₀值分别为2.95和2.39mg/L;对赤子爱胜蚯蚓14 d-LC₅₀值分别为171.73和383.37 mg/kg干土。依据国标《化学农药环境安全评价试验准则》(GB/T31270—2014)的毒性等级划分标准,噻呋酰胺和环酰菌胺对家蚕、赤子爱胜蚯蚓的急性毒性为低毒,对意大利工蜂、斑马鱼的急性毒性为中毒。以上结果说明噻呋酰胺和环酰菌胺对4种非靶标生物安全。该结果可为2种药剂的使用及环境风险评估提供理论依据。     

4种不同剂型甲氨基阿维菌素苯甲酸盐对6种非靶标生物的急性毒性效应

为探究同一有效成分不同剂型农药对环境非靶标生物的毒性差异,开展了4种不同剂型甲氨基阿维菌素苯甲酸盐对日本鹌鹑、斑马鱼、大型溞、蜜蜂、家蚕和蚯蚓6种生物的急性毒性试验。结果表明,5.7%甲氨基阿维菌素苯甲酸盐乳油、3.4%甲氨基阿维菌素苯甲酸盐微乳剂、5.7%甲氨基阿维菌素苯甲酸盐悬浮剂和5.7%甲氨基阿维菌素苯甲酸盐水分散粒剂对日本鹌鹑的毒性分别为中毒、中毒、中毒和高毒;对斑马鱼的毒性分别为剧毒、剧毒、高毒和剧毒;对大型溞的毒性均为剧毒;对蜜蜂的接触毒性均为高毒;对家蚕的毒性均为剧毒;对蚯蚓的毒性分别为低毒、低毒、低毒和中毒。由此可见,甲氨基阿维菌素苯甲酸盐对不同非靶标生物的毒性存在差异。同时,不同剂型甲氨基阿维菌素苯甲酸盐对同一种非靶标生物的毒性也存在差异。其中,甲维盐悬浮剂和微乳剂对各非靶标生物相对安全友好,水分散粒剂和乳油对各非靶标生物的安全性相对较差。因此,在使用甲维盐过程中,建议远离鸟群、桑园、水体及蜂群,并避免与土壤混用,以减少对非靶标生物造成的危害。     

生物催化剂的高通量筛选方法

生物催化技术是工业可持续发展最有希望的技术，生物催化剂有着很好的应用前景。介绍了高通量筛选生物催化剂的常用方法。     

生物催化剂的应用与筛选研究进展

以微生物细胞和酶为代表的生物催化剂,已成为现代化学合成中不可或缺的有利工具,并日益广泛地应用于化工产品的生产中。本文主要介绍了生物催化剂的应用及筛选。     

食品中生物胺提取技术的研究进展

生物胺是具有生物活性的小分子碱性含氮化合物。在天然食品发酵和食品加工过程中,由于微生物、物理因素的影响,难以抑制或杜绝生物胺的形成,因而建立食品中生物胺的准确、灵敏检测对人体健康安全和风险规避具有重要意义。基于此,介绍了食品中生物胺的种类,详细综述了不同前处理方法包括：液液萃取、分散液液微萃取的液相萃取法,传统固相萃取、分子印迹固相萃取、固相微萃取、基质辅助固相分散萃取、吸附分离的固相萃取方法,以及电膜萃取的优缺点和最新进展,为食品中生物胺的高效分析提供理论基础。     

黄酒中生物胺的分析研究

采用丹磺酰氯为衍生试剂,建立了反相高效液相色谱法同时测定腐胺、尸胺、酪胺和组胺4种生物胺的方法,色谱条件为：C18色谱柱分离,甲醇和0．1％乙酸溶液为流动相梯度洗脱,流速0．8mL／min,二极管阵列检测器,检测波长为254nm。以1,7-二氨基庚烷为内标。给定条件下4种生物胺得到了较好的分离,线性相关性良好（r〉0．998）。腐胺、尸胺和酪胺的检测限为0．8蚓InL,组胺为4μg/mL。检测方法具有良好的重现性和回收率。在对几种黄酒中生物胺的分析发现4种含有腐胺,3种含有酪胺,各有一种含有组胺和尸胺,最高生物胺含量为435．5μg／g。     

尿基复合肥防结块活性物质的筛选

通过尿素分子与水分子之间所形成氢键的讨论,来说明尿基复合肥形成结块的部分原因,并用经验方程y=axb ccos((xπ)/d)来指导包裹油中防结块活性物质及其质量浓度的筛选。     

3种典型叠氮胺的萃取剂筛选

依据Hansen基团贡献法分别计算了N,N–二甲基叠氮乙胺(DMAZ)、N,N–双叠氮乙基甲胺(BAZ)、三叠氮乙胺(TAEA)3种典型液体叠氮胺的溶度参数,并计算了其梯度溶度参数分量;结合一些常见有机溶剂的梯度溶度参数分量作参数贡献分布图。通过萃取实验测试了不同溶剂对水溶液中叠氮胺的萃取效果,实验结果表明,V(乙酸乙酯):V(二氯甲烷)=1:1的混合溶剂对水溶液中叠氮胺的溶解能力最好。分析了萃取条件对叠氮胺收率的影响,结果发现,温度为30℃,混合时间为10 min,搅拌速率为500 r/min,溶剂溶质体积比为1:4,萃取4次,最大收率可达90%。萃取完成后的有机溶剂经回收后可循环利用,全部工艺绿色环保。     

天然产物抗氧化活性的常见评价方法

天然产物抗氧化活性的评价是天然产物研究的重要组成部分,对其在日化领域的开发应用具有显著的指导意义。本文从实验原理、实验方法等方面对天然产物抗氧化活性的常见评价方法进行综述,详细介绍了化学分析法中的自由基(ABTS自由基阳离子、DPPH自由基、超氧自由基、羟自由基)清除实验、脂质过氧化抑制实验、还原能力测定及脂质氧化抑制等评价方法;描述了以生物细胞为模型的CAA抗氧评价方法;概述了在动物体内进行的抗氧化活性评价方法及指标,为相关领域中抗氧化天然产物的研究和开发提供实验理论基础。     

The search for novel human pancreatic alpha-amylase inhibitors: high-throughput screening of terrestrial and marine natural product extracts

Specific inhibitors of human pancreatic alpha-amylase (HPA) have potential as oral agents for the control of blood glucose levels in the treatment of diabetes and obesity. In a search for novel inhibitors, a library of 30 000 crude biological extracts of terrestrial and marine origin has been screened. A number of inhibitory extracts were identified, of which the most potent was subjected to bioassay-guided purification. A family of three glycosylated acyl flavonols, montbretins A-C, was thereby identified and characterized as competitive amylase inhibitors, with K(i) values ranging from 8.1-6100 nM. Competitive inhibition by myricetin, which corresponds to the flavone core, and noncompetitive inhibition by a second fragment, ethyl caffeiate, suggest a binding mode for these inhibitors.     

Ionic liquids for absorption and separation of gases: An extensive database and a systematic screening method

Ionic liquids (ILs) have attracted considerable attention in both the academic and industrial communities for absorbing and separating gases. However, a data‐rich and well‐structured systematic database has not yet been established, and screening for highly efficient ILs meeting various requirements remains a challenging task. In this study, an extensive database of estimated Henry's law constants of twelve gases in more than ten thousand ILs at 313.15 K is established using the COSMO‐RS method. Based on the database, a new systematic and efficient screening method for IL selection for the absorption and separation of gases subject to important target properties is proposed. Application of the database and the screening method is highlighted through case studies involving two important gases separation problems (CO₂ from CH₄ and C₂H₂ from C₂H₄). The results demonstrate the effectiveness of using the screening method together with the database to explore and screen novel ILs meeting specific requirements for the absorption and separation of gases. © 2017 American Institute of Chemical Engineers AIChE J, 63: 1353–1367, 2017     

Phospholipases: Occurrence and production in microorganisms,assay for high-throughput screening,and gene discovery from natural and man-made diversity

Various kinds of phospholipids have wide industrial applications such as in food and nutraceuticals, cosmetics, agricultural products, and pharmaceuticals. The demand for reliable biocatalysts for the production of phospholipid products, such as phospholipases A₁, A₂, C, and D, has steadily increased over the past several decades. A large number of microbial phospholipases have been isolated and characterized, and the increasing availability of these enzymes could eventually lead to the sustained development of phospholipid-related biotechnology. Although a number of reactions have been performed using phospholipases, a reliable and efficient supply of superior phospholipases in quantity is still a challenge for their practical application. High-throughput functional assay methods for phospholipases should be devised to develop superior new species from the huge diversity of phospholipases. Recent biotechnological advances in the discovery of new phospholipase genes from natural sources, such as extremophiles of phospholipases by protein engineering, such as directed evolution, can provide valuable means of rapidly developing practical uses of phospholipases for various applications.