947 resultados para RP-HPLC


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本文以9 个芍药野生种(15 份种质)、104 个品种及2 个牡丹芍药组间杂种的花瓣为材料,利用液质联用技术鉴定了花瓣中的色素成分并探讨了芍药花色形成的化学机制和化学分类法。 结果表明,芍药花中主要含有5 种花青素,即芍药花素-3,5-二葡糖苷( peonidin-3,5-di-O-glucoside , Pn3G5G ); 矢车菊素-3 , 5- 二葡糖苷( cyanidin-3,5-di-O-glucoside , Cy3G5G ); 天竺葵素-3 , 5- 二葡糖苷( pelargonidin-3,5-di-O-glucoside , Pg3G5G ); 芍药花素-3- 葡糖苷(peonidin-3-O-glucoside,Pn3G)和矢车菊素-3-葡糖苷(cyanidin-3-O-glucoside,Cy3G)。此外,3 种微量的花青素首次在芍药中发现:它们分别为芍药花素-3-葡萄糖-5-阿拉伯糖苷(peonidin-3-O-glucoside-5-O-arabinoside,Pn3G5Ara)、矢车菊素-3- 葡萄糖-5- 半乳糖苷( cyanidin-3-O-glucoside-5-O-galactoside ,Cy3G5Gal)和天竺葵素-3-葡萄糖-5-半乳糖苷(pelargonidin-3-O-glucoside-5-Ogalactoside,Pg3G5Gal)。特征花青素Cy3G5Gal 和Pg3G5Gal 仅在新疆芍药(Paeonia anomala L.)及其亚种川赤芍(P. anomala subsp. veitchii(Lynch) D. Y.Hong & K. Y. Pan)中被检测出来,表明它们属于同一个种。Pn3G5Ara 仅存在于欧洲的野生芍药花瓣中,表明中国野生芍药和欧洲芍药的花青素代谢途径不同。 芍药花瓣中主要含有11 种花黄素,均为黄酮醇类物质。包括栎精-3,7 二葡糖苷( quercetin-3,7-di-O-glucoside )、山奈酚-3 , 7 二葡糖苷(kaempferol-3,7-di-O-glucoside)、异鼠李素-3,7 二葡糖苷(isorhamnetin-3,7-di-Oglucoside)、栎精-3-O-(6”-没食子酰基)-葡糖苷 [quercetin-3-O-(6”-O-galloyl)-glucoside] 、栎精-3- 葡糖苷( quercetin-3-O-glucoside )、山奈酚-7- 葡糖苷( kaempferol-7-O-glucoside )、山奈酚-3-O- ( 6”- 没食子酰基) - 葡糖苷[kaempferol-3-O-(6”-O-galloyl)-glucoside]、异鼠李素-3-O-(6”-没食子酰基)-葡糖苷 [isorhamnetin-3-O- ( 6”-O-galloyl ) -glucoside] 、山奈酚-3- 葡糖苷(kaempferol-3-O-glucoside)、异鼠李素-3-葡糖苷(isorhamnetin-3-O-glucoside)和山奈酚-丙二酰葡糖苷(kaempferol-malonyl-glucoside)。此外,查耳酮在黄色的栽培品种‘黄金轮’和牡丹芍药组间杂交种‘伊藤杂种’中首次被检测到。其化学结构为查耳酮-2’-葡糖苷(chalcononaringenin 2’-O-glucoside),它是花瓣表现出黄色的主要色素,它与黄色牡丹野生种‘滇牡丹’(P. delavayi Franchet)花瓣中主要黄色色素成分一致。 通过对所有芍药野生种和栽培品种的色素分析,研究发现花青素是芍药花瓣中主要的色素,其中Pn3G5G 是花瓣中含量最高的花青素苷,其次为Cy3G5G。3G 型糖苷仅在少数品种中检测出来。此外,黄酮醇是芍药花瓣中重要的辅助色素。山奈酚苷是花瓣中含量最高的黄酮醇类,其次是栎精。 多元线性回归分析的结果表明,芍药花色的形成主要与花瓣中Pn3G5G、Cy3G5G 和Pg3G5G 的含量及总花青素量(TA)有关。根据8 种花青素结构与花色组成,将国内的野生种和大部分品种进行了化学分类:所有样本聚成3 大类,聚类后的树状图与其花色、花色素组成数据相一致,直观反映了野生种和栽培品种花色形成的化学背景和表型相似性程度。 芍药成色机理和化学分类的初步研究,对芍药新花色育种具有重要意义:芍药鲜红色花的育种中,育种亲本应具有高的Cy3G 含量、低的辅助色素效应指数。选育深紫色花或紫黑色花的品种,亲本应具有高的Pn3G5G 含量和低的Pg3G5G 含量。

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通过利用高效液相色谱-质谱联用技术,研究110 个不同基因型(包括3 个种和5 个种间杂种)葡萄品种的花色苷含量和成分特点。在所有品种中,最多鉴定出29 种花色苷。对葡萄的花色苷总量来说,一般情况下,欧亚种和欧美杂交种的花色苷含量较低,而野生种和砧木品种显著高于其它的种间杂种;在同一个种内,酿酒品种高于鲜食品种;在大多数高花色苷含量的种质中,二甲基花翠素类花色苷是主要的花色苷,而在低总花色苷量的品种,花青素类和花翠素类花色苷是主要的成分。此外,在欧亚种葡萄中,仅检测到单糖苷类花色苷,而在其它葡萄种质中,既有单糖苷花色苷又有双糖苷花色苷。在欧亚鲜食葡萄中,Pn-3-glucoside 是主要的花色苷,而在欧亚酿酒葡萄中,Mv-3-glucoside 是主要的花色苷。通过主成分分析,最终根据花色苷总量的不同和单、双糖苷含量的不同,110 个品种在散点图中被明显的分成3 部分。 通过连续两年调查3 个欧亚鲜食葡萄杂交组合的亲本和后代的花色苷含量来分析花色苷的遗传特点。共鉴定出16 种花色苷,且均为单糖苷类。母本中各花色苷的比例决定了后代中花色苷含量的比例,但是后代中花色苷的绝对含量不受亲本影响。不论亲本还是后代中,Peonidin 3-O-glucoside 和Malvidin3-O-glucoside 都是含量最高的花色苷。花色苷的有或无是寡基因控制的质量性状,而含量的多少是多基因控制的数量性状。通过主成分分析可以得知:在杂交后代中, peonidin 3-O-glucoside, malvidin 3-O-glucoside, delphinidin3-O-glucoside, cyanidin 3-O-glucoside, petunidin 3-O-glucoside, peonidin3-O-(6-O-coumaryl)-glucoside 和malvidin 3-O-(6-O-coumaryl)-glucoside 是影响果皮中花色苷总量的主要种类。花色苷的含量是一种高广义遗传力的性状,而且这种性状在两年间是稳定的(0.65-0.98)。 5 个不同基因型葡萄品种在成熟过程中果实品质的变化也被研究。始熟期开始后,果粒重量继续增加,果粒较大的鲜食品种增长很慢,而果粒较小的制汁和酿酒品种增长幅度很大;果实内两种主要的糖(葡萄糖和果糖)开始快速上升,且在整个成熟过程中保持1:1;有机酸的含量开始快速下降,苹果酸下降的幅度大于酒石酸。多酚物质在果实始熟期也发生巨大变化,花色苷快速积累。 ‘北紫’和‘梅鹿辄’中的花色苷在成熟前1-2 周达到最大值,‘黑奥林’、‘康可’和‘北醇’在整个成熟过程中花色苷一直增加;对非花色苷类多酚来说,‘黑奥林’和‘梅鹿辄’在果实成熟过程中一直增加,而在另3 个品种中是下降的;花色苷之间以及与黄酮醇之间成正相关,花色苷和酚酸成负相关关系,酚酸和黄酮醇也成负相关关系,黄烷醇物质之间以及与其它类黄酮物质之间成负相关关系。

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Uncooled, high-speed modulation of two-contact lasers is presented with ultra-low drive currents. Practical operation at 10Gb/s up to temperatures of 85°C and extinction ratios of 6dB are found for current swings which are less than 40% of conventional lasers.

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茉莉酸类化合物是一种具有诱导植物次生代谢,抵抗外来侵害,提高植物抗逆防御性等重要作用的植物激素,主要包括茉莉酸(JA)、茉莉酸甲酯(MeJA)及其异亮氨酸衍生物等。茉莉酸的化学合成已报道有十几种之多,但都还无法实现工业化生产,满足农业需求。 本文以α-羧基肉桂酸为起始原料,经过加氢还原、AlCl3-NaCl离子液体中的分子内F-C酰基化反应,HATU催化下与异亮氨酸结合三步反应,合成了一种茉莉酸类似物吲哚异亮氨酸甲酯结合物(Ind-IleMe),总收率约70 %。 用合成的Ind-IleMe、coronalon及MeJA对银杏叶进行诱导,银杏叶经盐酸甲醇溶液加热水解提取黄酮苷元,HPLC检测发现,经诱导后的银杏叶与对照相比银杏黄酮含量均有所增加,最高可诱导银杏叶黄酮含量增长15%—20%,最高诱导浓度coronalon 最低,为1 μmol/L,Ind-IleMe是10 μmol/L,MeJA的诱导浓度最高,大于等于100 μmol/L。 对MeJA诱导后银杏叶的生理生化中几个重要指标进行了测定,发现经诱导后SOD、MDA、PAL、蛋白活性或含量相对升高,叶绿素、可溶性糖含量相对降低,这与MeJA诱导提高银杏叶的逆境防御及次生代谢有关。 在植物的次生代谢中,挥发性气体(VOCs)具有防御草食动物及实现同种及不同种植物间信息交流的重要作用。本文应用自组装的炭阱吸附装置和固相微萃取(SPME)来收集诱导后的银杏叶、利马豆及三种酒中的挥发物,GC-MS检测进行定性定量分析,发现诱导后的银杏叶释放出更多的挥发性有机物,主要是石竹烯等一些参与植物防御机制的倍半萜类,通过对比炭阱吸附和SPME在挥发物的收集上,发现炭阱吸附具有吸附效率更高、样品可短期保存、重复进样分析、可定量等优越性,因此具有很好的发展前景。

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Rong Gao, Yun Zhang, Qing-Xiong Meng, Wen-Hui Lee, Dong-Sheng Li, Yu-liang Xiong and Wan-Yu Wang. Characterization of three fibrinogenolytic enzymes from Chinese green tree viper (Trimeresurus stejneger ) venom. Toxicon 36, 457-467, 1998.-From the venom of Chinese green tree viper (Trimeresurus stejnegeri), three distinct fibrinogenolytic enzymes: stejnefibrase-l, stejnefibrase-2 and stejnefibrase-3, were purified by gel filtration, ion-exchange chromatography and reverse-phase high-performance chromatograghy (HPLC). SDS-PAGE analysis of those three enzymes showed that they consisted of a single polypeptide chain with mel. wt of -50 000, 31 000 and 32 000, respectively. Like TSV-PA (a specific plasminogen activator) and stejnobin (a fibrinogen-clotting enzyme) purified from the same venom, stejnfibrase-1, -2 and -3 were able to hydrolyze several chromogenic substrate. On the other hand, different from TSV-PA. and stejnobin, stejnefibrase-l, -2 and -3 did not activate plasminogen and did not possess fibrinogen-clotting activity. The three purified enzymes directly degraded fibrinogen to small fragments and rendered it unclottable by thrombin. Stejnefibrase-2 degraded preferentially BE-chain while stejnefibrase-l and -3 cleaved concomitantly Ax and B beta-chains of fibrinogen. None of these proteases degraded the gamma-chain of fibrinogen. When correlated with the loss of clottability of fibrinogen, the most active enzyme was stejnefibrase-l. The activities of the three enzymes were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB), indicating that like TSV-PA and stejnobin, they are venom serine proteases. (C) 1998 Elsevier Science Ltd. All rights reserved.

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PR-bombesin is a bombesin-like peptide derived from the skin of tile Chinese red belly toad, Bombina maxima. The 8-residue segment of N-terminal of RP-bombesin, comprising four prolines and three basic residues, is extensively different front other bombes

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Horseflies are economically important blood-feeding arthropods and also a nuisance for humans, and vectors for filariasis. They rely heavily on the pharmacological propriety of their saliva to get blood meat and suppress immune reactions of hosts. Little information is available on horsefly immune suppressants. By high-performance liquid chromatography (HPLC) purification coupling with pharmacological testing, an immunoregulatory peptide named immunoregulin HA has been identified and characterized from salivary glands of the horsefly of Hybomitra atriperoides (Diptera, Tabanidae). Immunoregulin HA could inhibit the secretion of interferon-gamma (IFN-gamma) and monocyte chemoattractant protein (MCP-1) and increase the secretion of interteukin-10 (IL-10) induced by lipopolysaccharide (LIPS) in rat splenocytes. IL-10 is a suppressor cytokine of T-cell proliferative and cytokine responses. IL-10 can inhibit the elaboration of pro-inflammatory cytokines. Immunoregulin HA possibly unregulated the IL-10 production to inhibit IFN-gamma and MCP-1 secretion in the current experiments. This immunosuppression may facilitate the blood feeding of this horsefly. The current works will facilitate to understand the molecular mechanisms of the ectoparasite-host relationship. 2008 Elsevier Ltd. All rights reserved.

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From the venom of Trimeresurus jerdonii, a distinct thrombin-like enzyme, called jerdonobin. was purified by DEAF A-25 ion-exchange chromatography, Sephadex G-75 gel filtration, and fast protein liquid chromatography (FPLC). SDS-PAGE analysis of this enzyme shows that it consists of a single polypeptide chain with a molecular weight of 38,000. The NH2-terminal amino acid sequence of jerdonobin has great homology with venom thrombin-like enzymes documented. Jerdonobin is able to hydrolyze several chromogenic substrates. The enzyme directly clots fibrinogen with an activity of 217 NIH units/mg, The fibrinopeptides released, identified by HPLC consisted of fibrinopeptide A and a small amount of fibrinopepide B. The activities of the enzyme were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB). However, metal chelator (EDTA) had no effect on it. indicating it is venom serine protease. (C) 2000 Elsevier Science Ltd. All rights reserved.

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Jerdonobin and jerdofibrase are two serine proteases purified from the venom of Trimeresurus jerdonii. The Michaelis constant K-m and the catalytic rate constant K-cat of jerdonobin or jerdofibrase on three chromogenic substrates, H-D-Pro-Phe-Arg-pNA (S2302), H-D-Phe-pipecolyl-Arg-pNA (S2238), and H-D-Val-Leu-Lys-pNA (S2251) were obtained from lineweaver-Burk plots. Jerdofibrase could hydrolyze all three substrates, but jerdonobin had no detectable activity on S2251, suggesting a relatively broader substrate specificity for jerdofibrase than jerdonobin. By SDS-PAGE, jerdofibrase preferentially degraded Bbeta-chain of fibrinogen. It also degraded Aalpha-chain of fibrinogen with relatively slow activity, but did not act on the gamma-chain. In contrast, jerdonobin did not degrade fibrinogen within 12 h. Fibrinopeptides liberation test, identified by HPLC, showed jerdonobin released fibrinopeptide A and a small amount of fibrinopeptide B. Unlike jerdonobin, jerdofibrase mainly released fibrinopeptide B. These results indicate that the two enzymes differ in their ability to hydrolyze chromogenic substrates and in their actions on fibrinogen. (C) 2002 Elsevier Science Inc. All rights reserved.

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Several biochemical and biological activities such as phospholipase A(2), arginine esterase, proteolytic, L-amino acid oxidase, 5'nucleotidase, acetylcholinesterase, thrombin-like, anticoagulant, and hemorrhagic activities were determined for whole desiccated venom of Trimeresurus jerdonii. An acidic phospholipase (named TJ-PLA(2)) was purified by anionic exchange chromatography, gel filtration, and reverse phase HPLC. TJ-PLA(2) had a molecular weight of 16,000 and a pI of 4.8. TJ-PLA(2) was non-lethal to mice up to an i.p. dose of 15 mg/kg body weight and lacked neurotoxicity and myotoxicity. It induced edema in the footpads of mice. The purified enzyme inhibited ADP- and collagen-induced human platelet aggregation in a manner which was both dose- and time-dependent.

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A novel phospholipase A(2) (PLA(2)) with Asn at its site 49 was purified from the snake venom of Protobothrops mucrosquamatus by using SP-Sephadex C25, Superdex 75, Heparin-Sepharose (FF) and HPLC reverse-phage C-18 chromatography and designated as TM-N49

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Liriomyza huidobrensis Blanchard (Diptera: Agromyzidae) is a very serious and economically important pest around the world. Liriomyza huidobrensis in China was first reported from Kunming of Yunnan province in 1993. We report here that this pest has recen

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In eucaryotes, gene expression and control is a complex nonlinear process, where there are many control mechanisms and ways, both physic, chemical and informational control. By the exploration from the angle of biocybernetics, the authors suggest that gene expression is a co-control process. In this process, physic, chemical and informational feedback controls are associated and influential each other, and are cross and co-functional. The physic, chemical and informational control ways composed an order non-linear feedback control system in eucaryotes.

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Several mechanisms have been proposed to account for the origination of new genes. Despite extensive case studies, the general principles governing this fundamental process are still unclear at the whole-genome level. Here, we unveil genome-wide patterns