花青素转录因子调控机制及代谢工程研究进展

花青素是广泛存在于植物中的一类重要的类黄酮化合物, 在植物生长发育和人类营养保健方面具有重要价值。花青素的生物合成途径已经解析得比较清楚, 但花青素的代谢调控网络还在不断完善。调控花青素生物合成的转录因子主要包括MYB、bHLH和WD40三大类, 这些转录因子通过激活或抑制CHS、ANS和DFR等花青素途径关键结构基因的表达水平, 进而决定花青素积累的部位与水平。该文结合国内外花青素生物合成与转录调控方面的研究进展, 简要介绍了花青素的生物合成途径, 归纳总结了模式植物中花青素代谢调控的分子机理, 尤其是MYB、bHLH和WD40三类主要转录因子的调控机理, 以及这些转录因子在观赏植物和水果等经济作物花青素代谢工程中的应用。该文将为系统阐明花青素的转录调控机制和利用代谢工程改良花青素的相关研究提供有益参考。     

Noemi Controls Production of Flavonoid Pigments and Fruit Acidity and Illustrates the Domestication Routes of Modern Citrus Varieties

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Phenolic and anthocyanin fractions from wild blueberries (V. angustifolium) differentially modulate endothelial cell migration partially through RHOA and RAC1

The present study investigates the effect of anthocyanin (ACN), phenolic acid (PA) fractions, and their combination (ACNs:PAs) from wild blueberry powder (Vaccinum angustifolium) on the speed of endothelial cell migration, gene expression, and protein levels of RAC1 and RHOA associated with acute exposure to different concentrations of ACNs and PAs. Time-lapse videos were analyzed and endothelial cell speed was calculated. Treatment with ACNs at 60 μg/mL inhibited endothelial cell migration rate ( P ≤ 0.05) while treatment with PAs at 0.002 μg/mL ( P ≤ 0.0001), 60 μg/mL ( P ≤ 0.0001), and 120 μg/mL ( P ≤ 0.01) significantly increased endothelial cell migration rate compared with control. Moreover, exposure of HUVECs to ACNs:PAs at 8:8 μg/mL ( P ≤ 0.05) and 60:60 μg/mL increased ( P ≤ 0.001) endothelial cell migration. Gene expression of RAC1 and RHOA significantly increased 2 hours after exposure with all treatments. No effect of the above fractions was observed on the protein levels of RAC1 and RHOA. Findings suggest that endothelial cell migration is differentially modulated based on the type of blueberry extract (ACN or PA fraction) and is concentration-dependent. Future studies should determine the mechanism of the differential action of the above fractions on endothelial cell migration.     

Why are grape/fresh wine anthocyanins so simple and why is it that red wine color lasts so long?

Vitis vinifera red berries are characterized by anthocyanins whose chemical structures are among the simplest encountered in higher plants. On the contrary, many plants, including orchids, petunias, red cabbage, elderberries, potatoes for instance, have developed very complicated anthocyanins featuring side-chains at the available positions of the aglycone skeleton. Such pigments were shown to possess bio-physico-chemical properties not to be seen with the grape common anthocyanins. Among beverages (water, tea, beer, wine, coffee, juices, milk), red wine is the only one whose organoleptic properties improve with time and this is called ageing. The grape/fresh red wine pigments, after a few months, disappear from the wine giving birth to new pigments resulting from the wine spontaneous chemistry allowing it to remain red for many years. What are the wine pigments and why are they so stable is the purpose of this mini-review. The structural simplicity of grape anthocyanins and the long lasting colour of red wine is another French paradox; we call it French paradox II.     

Benzyl adenine restores anthocyanin pigmentation in suspension cultures of wild Vaccinium pahalae

The overriding influence of cytokinin source on flavonoid production in vitro was explored using a suspension culture system for Vaccinium pahalae. The substitution of kinetin by 20 μM benzyl adenine (BA) in the suspension culture media resulted in a three-fold increase in total anthocyanin yield, and a more rapid production during the cell culture cycle. Anthocyanin production reached a maximum after a 16–20 day interval in cultures containing an optimal kinetin concentration, but pigment accumulation peaked at only 12–16 days when BA was used as the sole cytokinin source. Unlike some other production systems which increase secondary metabolite production at the expense of cell growth, BA-supplementation promoted both increased growth and increased anthocyanin productivity. In BA-supplemented medium, cultures were not susceptible to typical osmotically-induced cell growth suppression. When, after multiple subcultures in kinetin-containing media, anthocyanin production capability was lost or diminished, productivity could be restored within 3 days after transfer of cells to a BA-supplemented medium. This revised version was published online in June 2006 with corrections to the Cover Date.     

7-Polyacylated delphinidin 3,7-diglucosides from the blue flowers of Leschenaultia cv. Violet Lena

The triacyl anthocyanins, Leschenaultia blue anthocyanins 1 and 2 (LBAs 1 and 2) were isolated from the blue flowers of Leschenaultia R. Br. cv. Violet Lena (Goodeniaceae), in which LBA 1 was present as a dominant pigment. The structure of LBA 1 was elucidated to be delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O-[6-O-(4-O-(6-O-(4-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranoside] by application of chemical and spectroscopic methods. Since LAB 2 was isolated in small amount, its structure was tentatively assigned as either delphinidin 3-(malonylglucoside)-7-[(glucosyl-p-coumaroyl)-(glucosylcaffeoyl)-glucoside] or delphinidin 3-(malonyl-glucoside)-7-[(glucosyl-caffeoyl)(glucosyl-p-coumaroyl)-glucoside]. This is the first report of the occurrence of 7-polyacylated anthocyanins in the family of Goodeniaceae, although others have been found in the families of the Ranunculaceae, Campanulaceae, and Compositae. Moreover, delphinidin 3-glycoside-7-di-(glucosylcaffeoyl)-glucoside has been reported only in the flowers of Platycodon grandiflorum (Campanulaceae). From a chemotaxonomical viewpoint, the Goodeniaceae may be closely related to the Campanulaceae.     

蓝莓的成分与保健功能的研究进展

越橘属蓝莓含有花青苷（花青素或酚配基,与糖的结合体）。紫檀芪、鞣花酸、超氧化物歧化酶、熊果酸、酚酸及不同维生素等生物活性成分。很早就报道蓝莓所含花青苷可加速视紫素的再生而有益于视力及眼部健康。近年的研究显示蓝莓具有抗氧化作用,预防癌症、降血脂、降胆固醇、增强记忆、抗衰老、增强人体免疫、保护视力、抗糖尿病等保健功能。因此蓝莓被认为是最有营养的食物之一。