奎尼酸生物合成的代谢工程

奎尼酸及其衍生物氢醌和苯醌等是一类重要的化工原料,可作为一些化学合成制剂和药物中间原料,且在食品和化学工业中有着广泛的应用。目前奎尼酸的制备方法有植物提取法、化学合成法、酶工程法和微生物发酵法,其中微生物发酵法是近年发展起来的一种十分经济有效的方法。在介绍奎尼酸的制备方法的基础上重点综述了应用代谢工程在生物合成奎尼酸基因工程菌的改造中的研究进展,其中涉及奎尼酸生物合成途径中相关基因及其酶的调控、中心代谢途径的改造和修饰等,并探讨了将来的发展前景。     

葡萄糖二酸研究进展

葡萄糖二酸是一种葡萄糖衍生物,可作为原料制备多种聚合物和生物质新能源,在化工领域具有广泛的应用价值,被认为是"最具价值的生物炼制产品"之一。葡萄糖二酸也具有调控体内激素、提高机体免疫功能、减少癌症病发的作用,它在食品和医药领域的关注度和市场需求逐年增加。目前葡萄糖二酸的制备主要依靠化学氧化法生产,用微生物法合成的研究还处于初级探索阶段。本文综述了葡萄糖二酸的在医药、化工等领域的应用前景,阐述了其生产方法及测定手段,并对微生物法生产葡萄糖二酸进行了展望。     

微生物发酵生产莽草酸及其树脂分离性能的探讨

莽草酸是一种具有较高药用价值的化合物,在医药、食品、工业等领域具有重要作用。莽草酸的生产方法很多,包括植物提取法、化学合成法、微生物发酵法等,从植物中提取时使用中草药植物八角茴香,化学合成时以环戊二烯和苯醌为原料,微生物发酵生产时以大肠杆菌、枯草芽孢杆菌等微生物为工程菌。本文就莽草酸的微生物发酵生产方法做简单介绍,阐述了莽草酸树脂分离性能等的研究,并对莽草酸未来发展应用做出展望。     

莽草酸合成途径元件库:现状与未来

<正>莽草酸广泛存在于自然界中,并在医药、工业、能源领域具有应用价值。莽草酸途径是植物和微生物合成芳香族氨基酸等重要化合物的关键代谢路径。近年来,合成生物学技术迅速发展,莽草酸途径已经成为合成生物学重要的研究对象。生物元件的挖掘、搜集、表征及标准化等一直是合成生物学研究的重要方向之一,文章从传统元件的收集与整理、标准化元件库的批     

金钟藤中酚类化合物的研究

从金钟藤(Merremia boisiana(Gagnep.)V.Ooststr.)的地上部分分离得到8个酚类化合物。通过光谱分析,分别鉴定为东莨菪内酯(1)、七叶内酯(2)、N-p-香豆酰酪胺(3)、3,5-二咖啡酰基奎尼酸甲酯(4)、3,4-二咖啡酰基奎尼酸甲酯(5)、3,4,5-三咖啡酰基奎尼酸甲酯(6)、槲皮素(7)以及山奈酚-3-β-D-半乳糖甙(8)。这些化合物均是首次从鱼黄草属(Merremia)植物中发现。     

代谢工程在芳香化合物生物合成研究中的应用

生物技术和代谢工程的发展促进了生物合成研究。概述了近年来利用微生物莽草酸途径进行芳香化合物生物合成研究的现况、代谢工程在提高天然芳香化合物产量和扩大合成非天然产生的芳香化合物范围的应用的进展 ,特别是整体代谢工程对提高第二代工程菌产量的作用。指出了生物合成法是生产氨基酸及其它生物小分子如奎尼酸、维生素和抗生素等的未来趋势 ,在工业化生产中有着广阔的应用前景。     

UHPLC法测定不同产地野菊花中4种有机酸和蒙花苷含量

建立采用UHPLC同时测定野菊花中绿原酸、3,4-二咖啡酰奎尼酸、3,5-二咖啡酰奎尼酸、4,5-二咖啡酰奎尼酸和蒙花苷含量的分析方法。UHPLC分析条件:Agilent ZORBAX RH C18色谱柱(50 mm×2.1 mm,1.8μm),检测波长326 nm,流动相为乙腈-0.1%磷酸水进行梯度洗脱,流速0.4 mL/min,柱温25℃。实验结果显示绿原酸、3,4-二咖啡酰奎尼酸、3,5-二咖啡酰奎尼酸、4,5-二咖啡酰奎尼酸、蒙花苷分别在1.20~24.00、1.16~23.20、2.23~44.60、1.75~35.00、2.25~45.00μg/mL范围内线性关系良好(r0.9998),平均回收率分别为98.08%、98.42%、97.75%、98.27%、98.36%;RSD分别为0.38%、1.50%、0.77%、0.81%、0.62%。UHPLC法分析速度快、高效、重复性好、结果准确简便,可用于野菊花中四种有机酸和蒙花苷含量的测定。     

琼脂糖印迹法：观察植物表皮细胞的一种简易方法

本文介绍一种获得完整植物器官表皮细胞大小和数目的简易方法：琼脂糖印迹法。该方法根据琼脂糖凝固时具有可塑性的原理,通过对材料固定、包埋、切胶和显微观察等步骤从而获得材料表皮细胞的轮廓。该方法具有简单迅速、图像清晰、观测结果准确且应用广泛等优点,可使统计植物发育过程中细胞数目及大小的工作变得简单易行。     

琼脂糖印迹法: 观察植物表皮细胞的一种简易方法

本文介绍一种获得完整植物器官表皮细胞大小和数目的简易方法: 琼脂糖印迹法。该方法根据琼脂糖凝固时具有可塑性的原理, 通过对材料固定、包埋、切胶和显微观察等步骤从而获得材料表皮细胞的轮廓。该方法具有简单迅速、图像清晰、观测结果准确且应用广泛等优点, 可使统计植物发育过程中细胞数目及大小的工作变得简单易行。     

甜菜碱的生产方法及应用

甜菜碱是一种季铵型生物碱,其制备方法有天然提取法和人工合成法。甜菜碱及其盐酸盐是一种高效甲基供体,能调节动物体内渗透压、促进脂肪代谢和蛋白质合成、对鱼虾有良好的诱食效果,在养殖业中是重要的饲料添加剂,另外在化工、医药、食品、发酵等行业也都有广泛的应用。     

Changes in bulk protein of tobacco leaves on aerobic autolysis: Hydrogenation studies and identification of bound quinic acid

During aerobic autolysis and in commercial curing, the bulk proteins of tobacco leaves become coupled with quinic acid, presumably in consequence of coupling of chlorogenic acid congeners with lysine ε-NH₂ groups. Quinic acid derivatives, prepared from acid hydrolysates of such altered proteins, were identified by GC-MS. Such proteins were also hydrogenated over Rh/Al₂O₃ with a view to stabilizing the hypothetical linkages. Difficulties in removing contaminant Al had to be overcome. Evidence was then obtained (by GLC of derivatives) for several components, in acid hydrolysates of hydrogenated altered proteins, which were neither normal hydrogenation products of the common amino acids nor derivatives of quinic acid. Details of the chromatograms and mass spectra of quinic acid derivatives are provided in a supplementary publications.     

Die organischen Säuren im Cambialsaft von Larix decidua Mill

Summary The quantitatively most important organic acids in the cambial sap of Larix decidua have been isolated and characterised. Quinic acid predominated and smaller amounts of shikimic acid, malic acid, oxalic acid, amino acids and sugar phosphates were also present. It is shown by the aphid-technique that quinic acid is probably transported in the phloem from the young needles and shoots to the cambial zones of the tree.

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Zweite Mitteilung über den Cambialsaft von Larix decidua. Erste Mitteilung in Planta (Berl.) 73, 155–160 (1967).     

Caffeoylquinic Acids: Separation Method,Antiradical Properties and Cytotoxicity

Twelve chlorogenic acid derivatives and two flavones were isolated from Moquiniastrum floribundum (Asteraceae, other name: Gochnatia floribunda). Compounds were evaluated in relation to their cytotoxicity and antiradical properties. Cytotoxicity was not observed for compounds, however, chlorogenic acid derivatives showed antiradical activity and were more active than the Trolox standard. Quinic acid esterified with caffeoyl group at C‐4 position showed higher antiradical activity compared to acylation at C‐3 or C‐5 positions. Additional caffeoyl groups esterified in quinic acid increase the antiradical activity observed for 4‐caffeoylquinic acid. Excepted to 3,4‐dicaffeoylquinic acid methyl ester, methyl ester derivatives show higher capacity of trapping radicals than their respective acids. Consequently, the presence of caffeoyl group at C‐4 position of quinic acid is suggested as fundamental to obtain the highest antiradical activity.     

Studies on chlorogenic acid biosynthesis in sweet potato root tissue using trans-cinnamic acid-2-14C and quinic acid-G-3H

When either trans-cinnamic acid-2-¹⁴C or quinic acid-G-³H wasadministered to sweet potato root discs, each compound was incorporatedinto chlorogenic acid. Hydrolysis analysis revealed that trans-cinnamicacid-2-¹⁴C and quinic acid-G-³H were selectively incorporatedinto the aromatic and non-aromatic moieties of chlorogenic acid,respectively. Quinic acid-G-³H was considered a more efficient precursor thantrans-cinnamic acid-2-¹⁴C, based on data of dilution values,incorporation percents and pool sizes in the tissue. No conjugatesof trans-cinnamic acid and quinic acid were detected in discsadministered trans-cinnamic acid-2-¹⁴C or quinic acid-G-³H.From these experimental results, a possible biosynthetic pathwayfor chlorogenic acid has been proposed. ¹ This paper constitutes Part 98 of the Phytopathological Chemistryof Sweet Potato with Black Rot or Injury. (Received November 2, 1971; )     

Production of shikimic acid

Shikimic acid is a key intermediate for the synthesis of the antiviral drug oseltamivir (Tamiflu®). Shikimic acid can be produced via chemical synthesis, microbial fermentation and extraction from certain plants. An alternative production route is via biotransformation of the more readily available quinic acid. Much of the current supply of shikimic acid is sourced from the seeds of Chinese star anise (Illicium verum). Supply from star anise seeds has experienced difficulties and is susceptible to vagaries of weather. Star anise tree takes around six-years from planting to bear fruit, but remains productive for long. Extraction and purification from seeds are expensive. Production via fermentation is increasing. Other production methods are too expensive, or insufficiently developed. In the future, production in recombinant microorganisms via fermentation may become established as the preferred route. Methods for producing shikimic acid are reviewed.     

枇杷果肉有机酸组分及有机酸在果实内的分布

用高效离子交换色谱（HPIC）测定了枇杷（Eriobotrya japonica Lindk）18个品种（小毛枇杷、夹脚、卓南1号、解放钟、富阳、森尾早生、华宝2号、香钟10号、白花、土肥、多宝2号、乌躬白、洛阳青、茂木、早钟6号、白梨、塘头4号和长红3号）的成熟果肉和2个品种（解放钟和早钟6号果）成熟果实不同组织有机酸含量。结果表明,成熟果肉中均含有苹果酸、奎尼酸、柠檬酸、异柠檬酸、α-酮戊二酸、富马酸、草酰乙酸、酒石酸8种有机酸,有的还含有微量的阿魏酸、顺乌头酸和B一香豆酸。大多数品种果肉中苹果酸含量最高,平均含量为4399mg kg^-1 FW,占总酸的62．7％;其次是奎尼酸,其平均含量为2042mgkg—FW,占总酸的29．1％。品种之间可滴定酸和有机酸含量差异很大。通过对果肉可滴定酸进行聚类分析,可把18个枇杷品种分为五个组群：极高酸（小毛枇杷）、高酸（夹脚、卓南1号、解放钟和富阳）、中酸（森尾早生、华宝2号、香钟10号、白花、土肥和多宝2号）、低酸（乌躬白、洛阳青、茂木和早钟6号）和极低酸（白梨、塘头4号和长红3号）。解放钟和早钟6号果肉和果皮的总酸含量及可滴定酸均无显著差异,但果皮和果肉的总酸含量和可滴定酸均大大高于种子。相似于果肉,果皮和种子的主要有机酸也是苹果酸和奎尼酸。果皮中苹果酸含量远高于奎尼酸,但种子中苹果酸含量比奎尼酸稍低。此外,种子中苹果酸和奎尼酸比果肉和果皮中的低得多。     

Relations polyphénols — croissance: Mise en évidence d'un effet inhibiteur des composés phénoliques sur le transport polarisé de l'auxine

Polyphenols and Growth: Inhibition of Polar Auxin Transport by Phenolic Compounds. The possible effects of polyphenols on auxin transport in tomato plants (Lycopersicum esculentum Mill.) were investigated. For this purpose, the phenolic content of the material was stimulated by exogenously supplied quinic acid. After the apical bud had been excised, labelled compounds were applied to the cut surface, and the radioactivity transported to the roots was measured. Quinic acid treatment significantly delayed polar transport of labelled auxins (IAA or NAA). It did not affect the migration rate of sucrose^?14C and leucine^?3H. A number of evidences seems to demonstrate that the phenolics are responsible for these modifications, since similar results were recorded when the labelled compounds were supplied simultaneously with polyphenols from tomato. Moreover, a decreased polarity of NAA transport could be observed when the plants were submitted to treatments which lead to an increased level of phenols (boron deficiency, infection by Fusarium oxysporum). The data presented in this paper suggest that phenolic compounds could act on growth processes via the regulation of polar auxin transport.     

Biochemical and structural characterisation of dehydroquinate synthase from the New Zealand kiwifruit Actinidia chinensis

One of the novel aspects of kiwifruit is the presence of a high level of quinic acid which contributes to the flavour of the fruit. Quinic acid metabolism intersects with the shikimate pathway, which is responsible for the de novo biosynthesis of primary and secondary aromatic metabolites. The gene encoding the enzyme which catalyses the second step of the shikimate pathway, dehydroquinate synthase (DHQS), from the New Zealand kiwifruit Actinidia chinensis was identified, cloned and expressed. A. chinensis DHQS was activated by divalent metal ions, and was found to require NAD⁺ for catalysis. The protein was crystallised and the structure was solved, revealing a homodimeric protein. Each monomer has a NAD⁺ binding site nestled between the distinct N- and C-terminal domains. In contrast to other microbial DHQSs, which show an open conformation in the absence of active site ligands, A. chinensis DHQS adopts a closed conformation. This is the first report of the structure of a DHQS from a plant source.     

Enhancement by catechols of hydroxyl-radical formation in the presence of ferric ions and hydrogen peroxide

The effect of caffeic acid, a kind of catechol, on the Fenton reaction was examined by using the ESR spin trapping technique. Caffeic acid enhanced the formation of hydroxyl radicals in the reaction mixture, which contained caffeic acid, hydrogen peroxide, ferric chloride, EDTA, and potassium phosphate buffer. Chlorogenic acid, which is an ester of caffeic acid with quinic acid, also stimulated the formation of the hydroxyl radicals. Quinic acid did not stimulate the reaction, suggesting that the catechol moiety in chlorogenic acid is essential to the enhancement of the hydroxyl-radical formation. Indeed, other catechols and related compounds such as pyrocatechol, gallic acid, dopamine, and noradrenaline effectively stimulated the formation of the hydroxyl radicals. The above results confirm the idea that the catechol moiety is essential to the enhancement. Ferulic acid, 4-hydroxy-3-methoxybenzoic acid, and salicylic acid had no effect on the formation of the hydroxyl radicals. The results indicate that the enhancement by the catechols of the formation of hydroxyl radicals is diminished if a methyl ester is formed at the position of the hydroxyl group of the catechol. In the absence of iron chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP, formation of hydroxyl radicals was not detected, suggesting that chelators are essential to the reaction. The enhancement of the formation of hydroxyl radicals is presumably due to the reduction of ferric ions by the catechols. Thus, the catechols may exert deleterious effects on biological systems if chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP are present.