196 resultados para Crassulaceae


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Inter-simple sequence repeat markers (ISSR) were used to estimate genetic diversity within and among 10 populations of Rhodiola chrysanthemifolia along Nianqingtangula Mountains and Brahmaputra, a species endemic to the Qinghai-Tibet Plateau and an endangered medicinal plant. Of the 100 primers screened, 13 produced highly polymorphic DNA fragments. Using these primers, 116 discernible DNA fragments were generated of which 104 (89.7%) were polymorphic, indicating substantial genetic diversity at the species level. Genetic diversity measured by the percentage of polymorphic bands (PPB) at the population level ranged from 21.97% to 48.8%. Analysis of molecular variance (AMOVA) showed that the genetic variation was found mainly among populations (77.3%), but no regional differentiation was discernible. Variance within populations was only 22.7%. The main factor responsible for this high level of differentiation among populations is probably the historical geographical and genetic isolation of populations in a harsh mountainous environment. Concerning the management of R. chrysanthemifolia, the high genetic differentiation of populations indicates the necessity of conserving the maximum possible number of populations. (c) 2006 Elsevier Ltd. All rights reserved.

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Genetic variation of 10 Rhodiola alsia ( Crassulaceae) populations from the Qinghai - Tibet Plateau of China was investigated using intersimple sequence repeat (ISSR) markers. R. alsia is an endemic species of the Qinghai - Tibet Plateau. Of the 100 primers screened, 13 were highly polymorphic. Using these primers, 140 discernible DNA fragments were generated with 112 (80%) being polymorphic, indicating pronounced genetic variation at the species level. Also there were high levels of polymorphism at the population level with the percentage of polymorphic bands (PPB) ranging from 63.4 to 88.6%. Analysis of molecular variance (AMOVA) showed that the genetic variation was mainly found among populations (70.3%) and variance within populations was 29.7%. The main factors responsible for the high level of differentiation among populations are probably the isolation from other populations and clonal propagation of this species. Occasional sexual reproduction might occur in order to maintain high levels of variation within populations. Environmental conditions could also influence population genetic structure as they occur in severe habitats. The strong genetic differentiation among populations in our study indicates that the conservation of genetic variability in R. alsia requires maintenance of as many populations as possible.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Nine microsatellite loci were developed, and are transferable, across the Madagascan succulents Bryophyllum daigremontianum, Bryophyllum delagoense (mother-of-millions) and their horticultural hybrid (Houghton's), from enriched libraries of the later two species. For B. delagoense, a tetraploid, three to 13 alleles per locus were found for native Madagascan (H-O = 0.4-1.0), and one to nine in invasive Australian (H-O = 0.0-1.0) samples. In addition for 91 Australian samples, only five multilocus genotypes were found (95% of individuals were of two genotypes), suggesting extensive clonality in its introduced range. These loci will be used to examine genetic diversity, hybrid origin and mating system in natural and introduced populations.

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South African citrus thrips (Scirtothrips aurantii) established adventitiously in Australia. Although it is a major horticultural pest in Africa, it is now advocated as a possible biological control agent against Bryophyllum delagoense Eckl. & Zeyh. (Crassulaceae). To evaluate the biocontrol potential of S. aurantii a two year field study was conducted on the western Darling Downs of southern Queensland. Imidacloprid insecticide was applied to two quadrats at each of 18 field sites to assess, in the absence of S. aurantii, the persistence of individual plants and to quantify propagule production and recruitment by this declared weed. A third quadrat was left, as a control, to be infested naturally by S. aurantii. When released from herbivory by thrips in the field, plants grew significantly more, flowered more, and were significantly more fecund than plants in the quadrats with S. aurantii. Increases in growth and fecundity translated into significantly increased plant numbers but not increased recruitment. Recruitment even declined in experimental quadrats, through the indirect effects of releasing plants from herbivory. Field sampling also revealed that S. aurantii may be sensitive to seasonal climatic fluctuations. These and other local climatic influences may limit the biological control potential of the insect.

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Ⅰ 虎杖聚酮类化合物生物合成相关基因的克隆及功能分析 虎杖 (Polygonum cuspidatum Sieb. et Zucc) 属于蓼科蓼属多年生草本植物,在中国和日本民间曾被广泛用于动脉粥样硬化、高血压、咳嗽、化脓性皮肤炎以及淋病的治疗,具有祛风利湿、散瘀定痛、止咳化痰等功效。而在现代医学上最令人瞩目和具有发展前景的是其在抗肿瘤、心血管保护、抗氧化方面的作用,相关疗效主要来自于虎杖中结构迥异、种类丰富的聚酮化合物及其衍生物资源。这些聚酮类化合物主要包括蒽醌、大黄素、大黄素-甲醚、大黄酚、芪类以及类黄酮化合物等。其中,大部分聚酮类化合物生物合成途径机制尚不明确,但可以肯定的是植物类型III聚酮合酶type III polyketide synthases (PKSs) 在这些聚酮化合物的生物合成起始反应中行使着关键的作用。因此,除了我们所熟悉的类黄酮化合物、芪类化合物之外,进一步分离和分析虎杖中其它重要聚酮类化合物生物合成所涉及的类型III聚酮合酶基因的是非常值得期待的。 目前,已经有14个植物类型III PKS基因被克隆和功能分析。植物类型III PKS的共同特征包括基因结构、序列相似性、保守的活性中心、酶学性质以及共同的催化机制等。显花植物(裸子植物和被子植物)中,植物类型III PKS的基因结构绝对保守,除了一个早期报道的金鱼草(Antirrhinum majus)查尔酮合酶chalcone synthase (CHS) 含有第二个内含子外,迄今为止所有已知的植物类型III PKS基因均含有一个内含子且该内含子位置保守。有趣的是,在本研究中,两个含有3个内含子的类型III PKS基因从虎杖中被分离,且两个基因3个内含子的位置完全保守,这是三内含子类型III PKS基因首次得到分离。除了新奇的基因结构外,体外功能分析显示上述两个基因还具有特殊的酶学性质和功能。 本论文围绕上述2个三内含子基因开展了以下工作: 虎杖中一个由三内含子基因编码的新型类型III聚酮合酶 一个类型III PKS的cDNA及其相应的基因(PcPKS2)从药用植物虎杖中被克隆。序列分析结果表明,PcPKS2的开放阅读框被3个内含子分隔,这是一个出人意料的发现,因为截至到目前为止,除了金鱼草一个CHS基因外,所有已知的类型III PKS基因均在固定位置上含有一个内含子。除了特殊的基因结构外,PcPKS2显示了一些有趣的特性:(i) CHS“守卫”苯丙氨酸——Phe215和Phe265在PcPKS2中双双缺失,它们分别被亮氨酸和半胱氨酸取代;(ii) 体外功能分析结果表明,当酶促反应体系的pH值为6.5-8.5时,大肠杆菌中过表达的重组PcPKS2高效地合成丁烯酮非环化产物——4-香豆酰甘油酸内酯(4-coumaroyltriacetic acid lactone (CTAL))为主产物,而丙烯酮非环化产物bis-noryangonin (BNY) 以及苯亚甲基丙酮为副产物;而当酶促反应体系的pH值为9.0时,PcPKS2高效地合成苯亚甲基丙酮为主产物,而CTAL、BNY为副产物。另外,除了上述3种产物外,在不同的pH条件下,还有痕量的柚皮素查尔酮能被检测到。此外,在4-香豆酰辅酶A(4-coumaroyl-CoA)的类似化合物中,除了4-香豆酰辅酶A外,只有feruloyl-CoA能够被PcPKS2接受作为起始底物。PcPKS2不接受脂肪酰辅酶A——异丁酰基辅酶A(isobutyryl-CoA)、异戊酰基辅酶A(isovaleryl-CoA)以及乙酰辅酶A(acetyl-CoA)作为起始底物。Southern blot杂交结果表明,在虎杖基因组中存在2-4个PcPKS2基因的拷贝。Northern blot杂交结果表明,在根茎和幼叶中,PcPKS2表达量很高,而在根中无表达。叶中的PcPKS2的表达受病原菌诱导,但不受伤诱导。 虎杖中一个编码双功能类型III聚酮合酶的三内含子基因的鉴定 显花植物中,所有已知的类型III PKS 基因均含有一个内含子且位置绝对保守。本研究中,综合运用PCR技术,从富含聚酮类化合物的植物虎杖中克隆得到一个类型III PKS 基因(PcPKS1)及其cDNA。序列分析结果表明,PcPKS1含有3个内含子。系统发育分析结果表明,PcPKS1与其它植物的CHSs归为一类。然而,体外功能分析结果表明,当酶促反应体系pH值为7.0时,大肠杆菌中过表达的重组PcPKS1高效地合成柚皮素查尔酮(naringenin)为单一产物;而当pH值为9.0时,苯亚甲基丙酮(p-hydroxybenzalacetone)几乎为重组PcPKS1的唯一产物。后续的研究表明,与典型的CHSs相比,PcPKS1具有另外一些不同的特点:在pH值为9.0时(PcPKS1的苯亚甲基丙酮合成活性最适pH值),在4-香豆酰辅酶A的类似化合物中,只有feruloyl-CoA能够被PcPKS1接受作为起始底物。与CHSs展现出的对脂肪酰辅酶A宽泛的底物特异性不同,在不同的pH条件下,PcPKS1不接受异丁酰基辅酶A(isobutyryl-CoA)、异戊酰基辅酶A(isovaleryl-CoA)以及乙酰辅酶A(acetyl-CoA)作为起始底物。以上数据指出重组PcPKS1是一个具有查尔酮合酶(CHS)和苯亚甲基丙酮合酶(BAS)活性的双功能酶。Southern blot杂交结果表明,在虎杖基因组中存在2-4个PcPKS1基因的拷贝。Northern blot杂交结果表明,PcPKS1可能在防御病原菌和草食动物方面起着重要作用。PcPKS1和PcPKS2共同从虎杖中被分离的事实极有可能暗示了苯丁烷类化合物(phenylbutanoid)及其衍生物存在于虎杖中。 Ⅱ 高山红景天酪醇生物合成代谢途径机制研究 高山红景天(Rhodiola sachalinensis A. Bor)是景天科(Crassulaceae)红景天属多年生草本植物,作为一种适应原性中草药在中国的应用史已经超过800年。最近红景天提取物作为一种重要的商业药用制剂资源,其应用遍及欧洲、亚洲和美国,其主要治疗范围包括抗变应性和消炎,提高心理机敏性等。目前已经非常明确,红景天甙(salidroside)和甙元酪醇(tyrosol)是红景天属植物的主要功效成分,主要分布于这类植物的根中并且具有抗缺氧、抗疲劳、延缓衰老、预防紫外线辐射伤害等功效。红景天甙为酪醇8-O-β-D葡萄糖甙,是酪醇在葡萄糖基转移酶UDP-glucosyltransferase (UGT) 的催化下糖基化后形成的,可以认为是酪醇在植物体内的贮存形式。酪醇作为一种重要的活性分子,同样存在于橄榄树和葡萄酒中。 虽然已经非常明确酪醇来自于莽草酸代谢途径,然而其具体的生物合成途径及其调控仍不明确。总结以往的报道,在酪醇的生物合成上主要存在两种观点:一是酪醇可能来自于苯丙烷代谢途径产生的4-香豆酸(4-coumaric acid)前体;二是来自于酪氨酸的酪胺(tyramine)可能是酪醇生物合成的直接前体。我们的工作兴趣主要围绕着鉴别高山红景天中的酪醇生物合成途径展开: 高山红景天内源苯丙氨酸解氨酶PALrs1的过表达对红景天甙积累的影响 红景天甙是来自于药用植物高山红景天的一种适应原性新型药物,其生物合成途径可能起始于苯丙氨酸或酪氨酸。由于高山红景天野生植物资源的匮乏和相对含量很低,阐明红景天甙的生物合成途径对于增加红景天甙的供给至关重要。在我们以前的工作中,运用cDNA末端快速扩增技术(RACE),一个编码苯丙氨酸解氨酶phenylalanine ammonia-lyase (PAL)的cDNA从高山红景天中被克隆,命名为PALrs1。在本研究中,PALrs1置于35S启动子+Ω增强子序列的控制下通过农杆菌(Agrobacterium tumefaciens)介导法转化回高山红景天。PCR 和 PCR–Southern blot分析结果表明,PALrs1已经整合到了转基因植物的基因组上。Northern blot杂交结果表明,PALrs1已经获得在转录水平上的高水平表达。与预期的结果相同,高效液相色谱High-performance liquid chromatography (HPLC)测定结果显示PALrs1的过表达引起4-香豆酸含量增长3.3倍。然而,与之相反的是,酪醇和红景天甙含量与对照相比反而分别下降4.7和7.7倍。此外,我们发现PALrs1的过表达造成酪氨酸含量下降2.6倍。这些数据暗示着PALrs1的过表达和4-香豆酸的积累并不能促进酪醇的生物合成。酪醇,作为一种苯乙烷类衍生物并非来自苯丙氨酸,而酪氨酸含量的下降则极有可能是酪醇生物合成和红景天甙积累大规模下降的直接原因。

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<正>红景天属景天科Crassulaceae红景天属Rhodiola植物,在我国作为传统民族用药广泛应用,具有抗疲劳、抗缺氧等功效。现认为红景天具有类似人参样的"适应原"样作

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根据笔者实测的青海高原高寒地区300余种植物稳定性碳同位素比值(δ13C)以及参阅已经发表过的国内外不同地区的C4植物名录,整理出青海高原高寒地区3 500余种植物中的C4植物.得出青海高原高寒地区共有9科32属的52种植物属于C4植物,禾本科(Gramineae)18属24种,藜科(Chenopodiaceae)9属20种,苋科(Amaranthaceae)1属4种,菊科(Compositae)2属3种,大戟科(Euphorbiaceae)、蒺藜科(Zygophyllaceae)、旋花科(Convolvulaceae)、景天科(Crassulaceae)、眼子菜科(Potamogetonaceae)各1属1种.同时归纳了52种C4植物的生活型以及地理分布区.

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The Rhodiola L. genus (Crassulaceae) is one of the most important medicinal plant products used by Tibetans in Chinese phytotherapy. Fourteen species were examined for their content of salidroside. A considerable quantitative variation was observed using high-performance liquid chromatography and this depended on species and regional factors. It was found that all samples contained salidroside at concentrations ranging between 0.02 mg g(-1) (R. sinuate) and 15.95 mg g(-1) (R. sacra), respectively. The content of salidroside in R. sacra was significantly higher than in other popular medicinal plants of this genus. This finding indicated that there may be more Rhodiola species present in the Qinghai-Tibet Plateau which may be used as a potential source of salidroside.

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Information on 12 exotic plants of diverse interest for the Galician flora are presented. All of them were collected in Ribeira council (SW of the A Coruña province). The total includes 8 novelties at a regional level (Aeonium haworthii, Aloe mitriformis, Brugmansia × candida, Nephrolepis cordifolia, Osteospermum ecklonis, Pelargonium capitatum, Sedum mexicanum, Sparaxis tricolor), and 2 provincial novelties. In addition, information on two taxa hardly mentioned in the literature on Galician vascular flora is also included. All the cited specimens are deposited at the SANT Herbarium.

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The demand for plant material of Rhodiola rosea L. (Crassulaceae) for medicinal use has increased recently, amid concerns about its quality and sustainability. We have analysed the content of phenylpropanoids (total rosavins) and salidroside in liquid extracts from 3-year old cultivated plants of European origin, and mapped the influence of plant part (rhizome versus root), genotype, drying, cutting, and extraction solvent to chemical composition. Rhizomes contained 1.5-4 times more salidroside (0.3-0.4% dry wt) and total rosavins (1.2-3.0%) than roots. The qualitative decisive phenylpropanoid content in the extracts was most influenced by plant part, solvent, and genotype, while drying temperature and cutting conditions were of less importance. We have shown that R. rosea from different boreal European provenances can be grown under temperate conditions and identified factors to obtain consistent high quality extracts provided that authentic germplasm is used and distinguished between rhizome, roots and their mixtures.

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Kalanchoe brasiliensis Cambess (Crassulaceae), commonly known as saião , coirama branca , folha grossa , is originally from Brazil and commonly found in São Paulo to Bahia, mainly in the coastal zone. Regarding of biological activities, most preclinical studies were found in the literature, mainly about the anti-inflammatory activity of extracts obtained from leaves and / or aerial parts of K. brasiliensis. As regards the chemical constitution, it has been reported mainly the presence of flavonoids in the leaves of the species, but until this moment did not knows which are the active compounds. Although it is a species widely used in traditional medicine in Brazil, there is no monograph about the quality parameters of the plant drug. In this context, this study aims to characterize and quantify the chemical markers of hydroethanolic extract (HE) from the leaves of K. brasiliensis, which can be used in quality control of plant drug and derivatives obtained from this species. The methodology was divided into two parts: i. Phytochemical study: to fractionate, isolate and characterizate of the chemical (s) marker (s) of the HE from the leaves of K. brasiliensis; ii. To Developed validate of analytical method by High Performance Liquid Chromatography (HPLC)-diode array detector (DAD) to quantify the chemical (s) marker (s) of the EH. i. The EH 50% was prepared by turbo extraction method. It was then submitted to liquid-liquid partition, obtaining dichloromethane, n-butanol and ethyl acetate (AcOEt) fractions. The AcOEt fraction was selected to continue the fractionation process, because it has a chemical profile rich in flavonoids. The acOEt fraction was submitted to column chromatography using different systems for obtaining the compound Kb1. To identify this compound, it was submitted to UV analysis ii. For quantitative analysis, the EH was analyzed by HPLC, using different methods. After selecting the most appropriate method, which showed satisfactory resolution and symmetrical peaks, it was validated according to parameters in the RE 899/2003. As result, it was obtained from the AcOEt fraction the compound Kb1 (2.7 mg). Until this moment, the basic nucleus was characterized by UV analysis using shift reagents. The partial chemical structure of the compound Kb1 was identified as a flavonol, containing hydroxyls in 3 , 4 position (ring A), 5 and 7 free (ring B) and a replacement of the C3 hydroxyl by a sugar. As the analysis were performed in the HPLC coupled to a DAD, we observed that the UV spectrum of the major peaks of EH from K. brasiliensis shown similar UV spectrum. According to the literature, it has been reported the presence of patuletin glycosydes derivatives in the leaves of this species. Therefore, it is suggested that the compound Kb1 is glycosylated patuletin derivative. Probably the sugar (s) unit(s) are linked in the C3 in the C ring. . Regarding the development of HPLC analytical method, the system used consists of phase A: water: formic acid (99,7:0,3, v / v) and phase B: methanol: formic acid (99,7:0,3, v / v), elution gradient of 40% B - 58% B in 50 minutes, ccolumn (Hichrom ®) C18 (250x4, 0 mm, 5 μm), flow rate 0.8 mL / min, UV detection at 370 nm, temperature 25 ° C. In the analysis performed with the co-injection of thecompound Kb1 + HE of K. brasiliensis was observed that it is one of the major compounds with a retention time of 12.47 minutes and had a content of 15.3% in EH of leaves from K. brasiliensis. The method proved to be linear, precise, accurate and reproducible. According to these results, it was observed that compound Kb1 can be used as a chemical marker of EH from leaves of K. brasiliensis, to assist in quality control of drug plant and its derivatives