764 resultados para DIVARICATA(DIV).


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模式植物金鱼草的花对称性分子发育及遗传学研究揭示了花对称性的相关调控基因在花发育过程种的表达模式和功能以及它们的相互作用机制。然而,被子植物的花对称性丰富多样,远非模式植物的模式所能概括。根据目前的研究我们选择苦苣苔科马铃苣苔属作为研究对象,选取其中具有代表性的种大叶石上莲开展控制花对称性的几个关键基因的进化发育生物学研究,初步探讨这些基因的表达模式和功能以及它们与花对称性进化的联系。 RT-PCR实验结果显示,在大叶石上莲中花对称性基因ObCYC, ObRAD, ObDIV与它们的同源基因CYC, RAD, DIV在金鱼草中的表达模式有着明显的差异,这也意味着这些基因的功能及相互作用也有所不同。首先,大叶石上莲的ObCYC1C基因的表达与金鱼草的CYC基因相似,结合花形态比较认为ObCYC1C基因在花器官近轴区域的表达抑制了背部花器官的发育,在构建大叶石上莲微弱的两侧对称花过程中起到了主导的作用; 其它的几个ObCYC基因有着完全不同于CYC的表达模式,ObCYC1D的表达延伸到了花腹部区域而ObCYC2A在花发育中期和晚期没有表达,这意味着它们可能具有除控制花对称性之外的功能; 另一个特殊的现象是ObCYC2B因为在可读框架中一个终止子的提前出现而失去了功能。其次,ObRAD, ObDIV的表达与RAD, DIV的表达差异也极为明显,通过系统树和氨基酸序列比对分析发现ObRAD, ObDIV与RAD, DIV的保守功能区序列存在明显的不同,而ObRAD, ObDIV与BlRAD, BlDIV的保守区很相似,这与它们的花对称性以及基因的表达模式相对映,同时也说明了保守功能区具有极重要的作用。本研究显示了大叶石上莲中的花对称性基因的表达模式和功能与模式植物金鱼草存在显著的差异,在此基础上开展更深入的进化发育生物学研究将有助于揭示花对称性基因的分子进化及其与花对称性表型进化的关系。

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被子植物菊亚纲原始类群的花为辐射对称花,伴随着适应性进化和传粉者的专性化,两侧对称花随之出现并快速进化和多样化。与花对称性相关的基因首先在模式植物金鱼草中被分离出来,它们包括TCP 基因家族的两个基因Cycloidea(CYC)和Dichotama(DICH),MYB 基因家族的两个基因Radialis(RAD)和Divaricata(DIV)。模式植物金鱼草的分子发育与遗传学研究初步揭示出在花对称性形成过程中相关调控基因的功能、表达模式及其相互作用机制。研究表明,金鱼草花中CYC 和DICH 基因只在背部表达,控制背部属性。DIV基因早期在所有部位表达,但只影响腹部属性。CYC 和DICH 通过激活与DIV具有颉抗作用的RAD 基因在背部的表达来抑制DIV 基因在背部的作用从而构建了金鱼草的两侧对称花。但是,被子植物繁杂多样的花对称性远非一种模式植物所能概括。此外,被子植物花对称性的演化也是一个悬而未决的问题。要全面了解被子植物花对称性的起源、多样化及其背后的决定机制,有必要进一步研究不同类群中花对称性相关基因的功能变化和进化式样。 苦苣苔科(Gesneriaceae)与金鱼草所属的车前科(Plantaginaceae)同属于菊亚纲的广义唇形目。研究表明广义唇形目的祖先已经具有了两侧对称花,苦苣苔科是广义唇形目的基部类群,具有与唇形目两侧对称花早期分化相关的各种两侧对称花类型。因此,在苦苣苔科选择两侧对称花代表类群开展花对称性的进化发育生物学研究十分有助于探讨苦苣苔科花对称性基因在两侧对称花类群的调控进化,从而揭示广义唇形目基部类群花对称性的进化发育模式。我们选择苦苣苔科两侧对称花类群烟叶唇柱苣苔(Chirita heterotricha)为主要研究材料。烟叶唇柱苣苔是苦苣苔科两侧对称性比较强烈的类群,主要体现在其只有腹部两枚雄蕊能育,背部和侧部雄蕊均败育,与金鱼草的近亲沙漠幽灵花(Mohaveae confertiflora)的形态类似。在沙漠幽灵花中CYC 类基因的表达从背部延伸到了侧部,但是在烟叶唇柱苣苔中是否遵循同一模式还是存在其他途径这是我们的主要研究目的。此外,我们发现在烟叶唇柱苣苔花序的顶花中偶尔会发生腹部化的辐射对称突变花。在金鱼草和柳穿鱼中,CYC 类基因的失活导致了辐射对称突变花的产生,而在豆科植物Cadia purpurea 中,CYC 类基因的活性从背部延伸到了侧部和腹部,导致了辐射对称花的形成。烟叶唇柱苣苔中的情形则值得我们关注。再者,革叶粗筒苣苔(Briggisia mihieri)是烟叶唇柱苣苔的近缘类群,但它具有四枚能育雄蕊(侧部和腹部各两枚)。苦苣苔科两能育雄蕊类群被认为起源于四能育雄蕊类群。我们在烟叶唇柱苣苔野生型两侧对称花和辐射对称突变花中开展花对称性基因的表达模式研究,结合在革叶粗筒苣苔中的研究,试图揭示烟叶唇柱苣苔两雄蕊类两侧对称花形成的分子机制和进化发育途径。 本研究从烟叶唇柱苣苔中分离到4 个CYC 类基因(ChCYC1C,ChCYC1D,ChCYC2A,ChCYC2B),2 个DIV 类基因(ChDIV1,ChDIV2)和2 个RAD 类基因(ChRAD1,ChRAD2)。从革叶粗筒苣苔中分离到4 个CYC 类基因(BmCYC1C,BmCYC1D,BmCYC2A,BmCYC2B),2 个DIV 类基因(BmDIV1,BmDIV2)和1 个RAD 类基因(BmRAD1)。序列和系统发育分析结果显示它们均为花对称性基因。进一步的表达分析显示结果表明:(1)不同拷贝CYC 类基因的表达存在着分化,与其氨基酸序列的分化一致;烟叶唇柱苣苔的CYC 类基因表达从背部延伸到了侧部而革叶粗筒苣苔的CYC 类基因仅在背部表达,与它们的形态分化密切相关。(2)DIV 类基因在种内两个拷贝以及种间的表达无明显的分化,在花的各个部位都有表达。(3)烟叶唇柱苣苔两个拷贝的RAD 类基因的表达存在分化;两个种的同类RAD 类基因的表达也存在分化。这些花对称性基因的表达模式分析揭示了它们在烟叶唇柱苣苔和革叶粗筒苣苔两侧对称花形态建成以及二者花形态的演化中具有重要作用。 同时,我们对烟叶唇柱苣苔的辐射对称突变花进行了自交和F1 代培育,但是F1 代没有出现稳定的辐射对称突变株。我们从辐射对称突变花中分离到的CYC 类、DIV 类和RAD 类基因的核苷酸序列与野生型的完全一致。说明突变体的产生与序列变异无关。RT-PCR 分析表明突变花中CYC 类基因全部失活,而DIV 类基因和在腹部表达的RAD 类基因的表达信号有所增强,这与其腹部化辐射对称的形态相一致。这进一步证实了花对称性基因在烟叶唇柱苣苔花形态建成中的作用。

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The distribution was studied by analysing the catches during four research vessel cruises in summer and eight cruises in winter in the period 1985 - 1993. The emmigration of young saithe, spending the larval and first juvenil stages in the inshore waters of Norway and Scotland, starts during the summer in an age of two years.

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花对称性,作为花器官的一个基本而又非常重要的特征,它的进化发育过程,越来越吸引着科学家们的注意力。次生辐射对称花的形成也越来越受到关注。然而在分子发育水平上,除了模式植物金鱼草(Antirrhinum majus)和少数其他种外,次生辐射对称花演化的机制仍然是一个巨大的未被探索的领域。 在金鱼草和柳穿鱼(Linaria vulgaris)中,腹部化反常整齐花的形成各自是由CYC和LCYC基因沉默所致,二者基因沉默分别是由于转座子的插入和DNA广泛甲基化所导致;而在豆科(legumes)中,辐射对称花的形成是由于legCYC基因在五个花瓣上都有表达,这种情况和金鱼草中CYC基因同源异位表达所形成的背部化辐射对称花相似。然而,自然起源的两侧对称花支系中的次生辐射对称花的形成似乎并不是简单的花对称性基因功能丢失或获得。自然形成的次生辐射对称花究竟可能经历了怎样的进化途径?对此,我们选择了广义唇形目(Lamiales sensu lato)中苦苣苔科(Gesneriaceae)植物——四数苣苔(Bouenea sinensis)作为研究对象,通过和模式植物金鱼草的突变体中花对称性基因表达特征比较,结合其近缘种——五数苣苔(Bournea leiophylla)中DIVARICATA在时间和空间上的表达特征,试图揭示苦苣苔科中可能的两侧对称向次生辐射对称花转变的新的演化途径,以及在这种进化过程中所产生的可能的器官丢失或融合现象。 四数苣苔和五数苣苔同属于苦苣苔亚科(Cyrtandroideae)苦苣苔族(Trib.Ramondeae Eritsch)中的四数苣苔属(Bournea Oliv)。该属仅仅有两个种——四数苣苔和五数苣苔,它们都是次生辐射对称花类群中的典型代表,而且两者花发育过程都显示出了由腹部向背部顺序发生和生长的特征。然而和五数苣苔相比,四数苣苔花瓣和雄蕊数目分别少了一枚,拥有四枚花瓣(背部花瓣两枚、两侧花瓣两枚)和四枚雄蕊(背部雄蕊一枚、两侧雄蕊两枚、腹部雄蕊一枚)。从形态特征比较来看,很有可能是四数苣苔在次生辐射对称花形成的过程中,发生了腹部花瓣的丢失和两枚腹部雄蕊愈合成了一枚较大的腹部雄蕊。那么,我们推测在四数苣苔次生辐射对称花形成过程中,花对称性基因即CYC类和DIV类基因在分子水平上发生了变化,这种变化和四数苣苔中次生辐射对称花的形成有关。 基于上述考虑,我们开展了对四数苣苔中花对称性基因——BsCYCLOIDEA、BsDIVARICATA、BsRADALIS以及BsCYCLIND3四个基因共9个拷贝进行了在花组织中表达模式研究。我们在四数苣苔中共分离到了五个拷贝的CYC类基因,分别命名为BsCYC1C-1、BsCYC1C-2、BsCYC1D、BsCYC2A、BsCYC2B。这五个拷贝在保守的TCP区和R区保持了高度的同源性。BsDIV的两个拷贝BsDIV1、BsDIV2也是如此,在保守的两个区domain I、domain II,尤其是在那些螺旋和环结构处,保守性相当高。组织原位杂交结果显示,BsDIV在四数苣苔中的表达非常特别,在金鱼草和五数苣苔中该类基因的表达分两个不同时期,即早期表达和晚期特异性表达,BsDIV在四数苣苔中似乎没有早期表达模式或者在很早期就已经进入到了晚期的表达模式。它在四个花瓣的两侧边缘和四个雄蕊上均等表达,而且这种表达持续时间相对比较长。组织原位杂交结果也得到了RT-PCR结果的支持。有趣的是BsRAD的RT-PCR结果显示,BsRAD在晚期花瓣上只在背部表达,但是在雄蕊上的表达却和金鱼草中AmRAD在背部区域表达不同,它的表达从背部延伸到了两侧和腹部。BsRAD在花器官的第二轮和第三轮的表达显然发生了分化。这种现象可能暗示着BsRAD功能发生了分化。BsRAD和BsDIV在腹部雄蕊上精细的时间空间调控关系可能正是导致腹部雄蕊愈合的原因。RT-PCR结果并没有检测到BsCYC2在晚期花上的表达。原位杂交结果显示BsCYC2在第8期以后表达就基本消失了,从而验证了RT-PCR结果。BsCYC2在早期花原基和早期花器官上都是均匀表达,但在表达消失之前,它在花瓣裂片和花冠筒的分界处则有表达信号,BsCYC2可能和调控花冠筒高度有关。根据Almeida 和 Galego(2002)所说,花冠筒高度的改变依赖于CYC 、DIV基因和其它非主动生长决定因子之间的相互作用。BsCYC1C晚期的RT-PCR结果显示它在背部花瓣、背部雄蕊和两侧雄蕊上均有表达信号,但在腹部花瓣和雄蕊上则没有表达信号,这似乎和四数苣苔由腹部向背部顺序发育的形态特征相符合,说明BsCYC1C可能起到了抑制背部花瓣和背部雄蕊生长的作用。

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Two new brominated selinane sesquiterpenes, 1-bromoselin-4(14), 11-diene (1) and 9-bromoselin-4(14), 11-diene (2), one known cadinane sesquiterpene, cadalene (3), and four known selinane sesquiterpenes, alpha-selinene (4), beta-selinene (5), beta-dictyopterol (6), and cyperusol C (7), were isolated from a sample of marine brown alga Dictyopteris divaricata collected off the coast of Yantai (China). Their structures were established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.

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A sample of the marine brown alga D. divaricata collected off the coast of Yantai (P. R. China) was dried, powdered, and extracted with the mixture of CHCl3 and MeOH (1: 1, v/v). By a combination of silica gel and Sephadex LH-20 column chromatography and preparative TLC, a new cadinane sesquiterpene 1,4-epoxymuurolan-5 beta-ol (1) was isolated from this species. Its structure was established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.

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Seven new cadinane sesquiterpenes, (-)-(1R,6S,7S,10R)-1-hydroxycadinan-3-en-5-one (1), (+)-(1R,5S,6R,7S, 10R)-cadinan-3-ene-1,5-diol (2), (+)-(1R,5R,6R,7S,10R)-cadinan-3-ene-1,5-diol (3), (+)-(1R,5S,6R,7S,10R)-cadinan-4(11)-ene-1,5-diol (4), (+)-(1R,5R,6R,7R,10R)-cadinan-4(11)-ene-1,5,12-triol (5), (-)-(1R,4R,5S,6R,7S, 10R)-cadinan-1,4,5-triol (6), and (-)-(1R,6R,7S,10R)-11-oxocadinan-4-en-1-ol (7), together with nine known compounds were isolated from the brown alga Dictyopteris divaricata. The structures of the new natural products, as well as their absolute configuration, were established by means of spectroscopic data including IR, HRMS, 1D and 2D NMR, single-crystal X-ray diffraction, and CD. All compounds were inactive against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), breast cancer (MCF-7), hepatoma (Bel7402), and colon cancer (HCT-8) cell lines.

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Five minor sesquiterpenes (1-5) with two novel carbon skeletons, together with a minor new oplopane sesquiterpene ( 6), have been isolated from the brown alga Dictyopteris divaricata. By means of spectroscopic data including IR, HRMS, 1D and 2D NMR, and CD, their structures including absolute configurations were assigned as (+)-(1R, 5S, 6S, 9R)3- acetyl-1-hydroxy-6-isopropyl-9-methylbicyclo[4.3.0] non-3-ene ( 1), (+)-(1R, 3S, 4S, 5R, 6S, 9R)-3-acetyl-1,4-dihydroxy-6- isopropyl-9-methylbicyclo[4.3.0] nonane (2), (+)-(1R, 3R, 4R, 5R, 6S, 9R)-3-acetyl-1,4-dihydroxy-6-isopropyl-9-methylbicyclo[ ;4.3.0] nonane ( 3), (+)-(1S, 2R, 6S, 9R)-1-hydroxy-2-(1-hydroxyethyl)-6-isopropyl-9-methylbicyclo[4.3.0] non-4-en-3-one (4), (-)-( 5S, 6R, 9S)-2-acetyl-5-hydroxy-6-isopropyl-9-methylbicyclo[4.3.0] non-1-en-3-one ( 5), and (-)-( 1S, 6S, 9R)- 4-acetyl- 1-hydroxy-6-isopropyl-9-methylbicyclo[ 4.3.0] non-4-en-3-one ( 6). Biogenetically, the carbon skeletons of 1-6 may be derived from the co-occurring cadinane skeleton by different ring contraction rearrangements. Compounds 1-6 were inactive (IC50 > 10 mu g/mL) against several human cancer cell lines.

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Three bisnorsesquiterpenes (1-3) with novel carbon skeletons and a norsesquiterpene (4) have been isolated from the brown alga Dictyopteris divaricata. By means of spectroscopic data including IR, HRMS, 1D and 2D NMR techniques, single-crystal X-ray diffraction, and CD, their structures including absolute configurations were proposed as (+)-1R,6S,9R)-1-hydroxyl-6-isopropyl-9-methylbicyclo[4.3.0]non-4-en3-one (1), (-)-(1S,6S,9R)-1-hydroxyl-6-isopropyl-9-methylbicyclo[4.3.0] non-4-en-3-one (2), (+)-(5S,6R,9S)5-hydroxyl-6-isopropyl-9-methylbicyclo [4.3.01 non-1-en-3-one (3), and (-)-(1R,7S,10R)-1-hydroxy-1lnorcadinan-5-en-4-one (4). Biogenetically, the carbon skeleton of 1-3 may be derived from the co-occurring cadinane skeleton by ring contraction and loss of two carbon units, and compound 4 from the oxidation of cadinane derivatives. Compounds 1-4 were inactive (IC50 > 10 mu g/mL) against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), breast cancer (MCF-7), hepatoma (Bel7402), and colon cancer (HCT-8) cell lines.

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A new sesquiterpene-substituted benzoic acid has been isolated from the brown Alga Dictyopteris divaricata Okam.. Its structure was elucidated as 3-[(2-hydroxy-2,5,5,8a-tetramethyldecahydro-1-naphthalenyl)methyl]-4-hydroxybenzoic acid, named dictyvaric acid on the basis of spectroscopic methods including IR, HRFABMS, 1D and 2D NMR techniques.

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UANL

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Como se estivesse tecendo num antigo tear manual, a linha narrativa de El retorno de Eva, da escritora paraguaia Susana Gertopan, vai compondo, com os fios da tradição e da modernidade, memória e história, exílio e retorno, a trajetória de uma jovem mulher em busca de si na condição de cidadã paraguaia e judia. Enquanto a protagonista busca desfazer-se dos diversos nós que a vinculam a uma herança cultural e religiosa que não combina, como ela mesma diz, com o cenário no qual cresce, e nem com a vida moderna de Jerusalém, terra prometida dos seus antepassados para onde emigra, vamos observando a problemática tessitura de sua individualidade entre dois mundos, ambos em crise e transição.

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Luigi Vincenzi ; con app. allo scritto di Massimo d'Azeglio sull'emancipazione degl'israeliti