65 resultados para DICTYOTA-DICHOTOMA


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Protein extracts from 22 species of marine macroalgae from Florida and North Carolina were compared for their abilities to agglutinate sheep and rabbit erythrocytes. Protein extracts from 21 algal species agglutinated rabbit erythrocytes compared to 19 for sheep erythrocytes. However, agglutination by brown algal extracts was variable. The agglutination produced by protein extracts from Dictyota dichotoma could be blocked by addition of polyvinylpyrrolidone. Protein extracts from North Carolina macroalgae were also tested against five bacterial species. Three of these agglutinated bacterial cells. Ulva curvata and Bryopsis plumosa agglutinated all five species. Protein extracts from five species of Florida algae were tested for their effects on mitogenesis in mouse splenocytes and human lymphocytes. Gracilaria tikvahiae HBOI Strain G-5, Ulva rigida and Gracilaria verrucosa HBOI Strain G-16S stimulated mitogenesis in mouse splenocytes, while Gracilaria tikvahiae HBOI Strain G-16stimulated mitogenesis in human lymphocytes.

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Fourteen commonly occurring species of marine benthic algae, i.e., Colpomenia sinuosa (Mertens ex Roth) Derbes et Solier, Dictyopteris australis (Sonder) Askenasy, Dictyota dichotoma (Hudson) Lamouroux D. dumosa Børgesen, D. hauckiana Nizamuddin, D. indica Sonder, D. maxima Zanardini, Hincksia mitchelliae (Harvey) Silva, Jolyna laminarioides Guimardes in Guimarâes et al., Padina tetrastromatica Hauck, Sargassum tenerrinum J. Agardh, Spatoglossum variabille Figari et De Notaris, Stoechospermum marginatum (C. Agardh) Kültzing and Stokeyia indica Thivy et Doshi, belonging to all three classes of Phaeophyta, were collected from coastal areas near Karachi, Pakistan and their taxonomy determined. Although all are taxonomically known species, Dictyota dichotoma, D. dumosa, D. hauckiana, D. indica, D. maxima, Jolyna laminarioides, Padina tetrastromatica, Sargassum tenerritnum and Stokeyia indica are described for the first time from the coast of Pakistan.

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The production of volatile organic compounds (VOC) by plants is well known. However, few scientific groups have studied VOC produced by green, brown and red algae. Headspace collection of volatiles and solid phase microextraction, as well as the traditional extraction by hydrodistillation combined with analytical chromatographic techniques (i.e., GC-MS), have significantly improved the investigation of VOC from plants and algae. The major volatile compounds found in seaweeds are hydrocarbons, terpenes, phenols, alcohols, aldehydes, ketones, esters, fatty acids and halogen or sulfur-containing compounds. This article presents an overview of VOC isolated from and identified in marine macro-algae. Focus is given to non-halogenated and non-sulfur volatile compounds, as well as strategies to analyze and identify algal VOC by GC-MS.

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In search of a meaningful stress indicator for Fucus vesiculosus we found that the often used quantitative determination procedures for the polysaccharide laminarin (beta-1,3-glucan) result in different kind of problems, uncertainties and limitations. This chemical long-term storage form of carbon enables perennial brown algae in seasonally fluctuating ecosystems to uncouple growth from photosynthesis. Because of this high ecological relevance a reliable and precise method for determination and quantification of laminarin is needed. Therefore, a simple, cold water extraction method coupled to a new quantitative liquid chromatography-mass spectrometrical method (LC-MS) was developed. Laminarin was determined in nine out of twelve brown algal species, and its expected typical molar mass distribution of 2000-7000 Da was confirmed. Furthermore, laminarin consisted of a complex mixture of different chemical forms, since fifteen chemical laminarin species with distinct molecular weights were measured in nine species of brown algae. Laminarin concentrations in the algal tissues ranged from 0.03 to 0.86% dry weight (DW). The direct chemical characterization and quantification of laminarin by LC-MS represents a powerful method to verify the biochemical and ecological importance of laminarin for brown algae. Single individuals of Laminaria hyperborea, L. digitata, Saccharina latissima, F. serratus, F. vesiculosus, F. spiralis, Himanthalia elongata, Cystoseira tamariscifolia, Pelvetia canaliculata, Ascophyllum nodosum, Halidrys siliquosa and Dictyota dichotoma were collected in fall (18.11.2013) during spring low tide from the shore of Finavarra, Co. Clare, west coast of Ireland (53° 09' 25'' N, 09° 06' 58'' W). After sampling, the different algae were immediately transported to the lab, lyophilized and sent to the University of Rostock. Laminarin was extracted with cold ultrapure water from the algal samples. Before extraction they were ground to < 1 mm grain size with an analytical mill (Ika MF 10 Basic). The algal material (approx. 1.5 g DW) was extracted in ultrapure water (8 mL) on a shaker (250 rpm) for 5 h. After the addition of surplus ultrapure water (4 mL) and shaking manually, 1 mL of the sample was filter centrifuged (45 µm) at 14,000 rpm (Hettich Mikro 22 R). The slightly viscous supernatant was free of suspended material and converted into a microvial (300 µL) for further analysis. The extracts were analyzed using liquid chromatography-mass spectrometry (LC-MS) analysis (LTQ Velos Pro ion trap spectrometer with Accela HPLC, Thermo Scientific). Laminarin species were separated on a KinetexTM column (2.6 µm C18, 150 x 3 mm). The mobile phase was 90 % ultrapure water and 10 % acetonitrile, run isocratically at a flow rate of 0.2 mL min-1. MS was working in ESI negative ion mode in a mass range of 100 - 4000 amu. Glucose contents were determined after extraction using high-performance liquid chromatography (HPLC). Extracted samples were analyzed in an HPLC (SmartLine, Knauer GmbH) equipped with a SUPELCOGELTM Ca column (30 x 7,8 mm without preColumn) and RI-detector (S2300 PDA S2800). Water was used as eluent at a flow rate of 0.8 mL min-1 at 75 °C. Glucose was quantified by comparison of the retention time and peak area with standard solutions using ChromGate software. Mannitol was extracted from three subsamples of 10-20 mg powdered alga material (L. hyperborea, L. digitata, S. latissima, F. serratus, F. vesiculosus, F. spiralis, H. elongata, P. canaliculata, A. nodosum, H. siliquosa) and quantified, following the HPLC method described by Karsten et al. (1991). For analyzing carbon and nitrogen contents, dried algal material was ground to powder and three subsamples of 2 mg from each alga thalli were loaded and packed into tin cartridges (6×6×12 mm). The packages were combusted at 950 °C and the absolute contents of C and N were automatically quantified in an elemental analyzer (Elementar Vario EL III, Germany) using acetanilide as standard according to Verardo et al. (1990).

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Continuous anthropogenic CO2 emissions to the atmosphere and uptake by the oceans will cause a reduction of seawater pH and saturation state (Omega) of CaCO3 minerals from which marine calcifiers build their shells and skeletons. Sea urchins use the most soluble form of calcium carbonate, high-magnesium calcite, to build their skeleton, spines and grazing apparatus. In order to highlight the effects of increased pCO2 on the test thickness and carbonate elemental composition of juvenile sea urchins and potential differences in their responses linked to the diet, we performed a laboratory experiment on juvenile Paracentrotus lividus, grazing on calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea, Dictyota dichotoma) macroalgae, under different pH (corresponding to pCO2 values of 390, 550, 750 and 1000 µatm). Results highlighted the importance of the diet in determining sea urchin size irrespectively of the pCO2 level, and the relevance of macroalgal diet in modulating urchin Mg/Ca ratio. The present study provides relevant clues both in terms of the mechanism of mineral incorporation and in terms of bottom-up processes (algal diet) affecting top-down ones (fish predation) in rocky subtidal communities

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为了阐明蕨类植物铁芒萁(Dicranopteris dichotoma Bernh.)体内稀土元素的分布及其光合特性,采用电感耦合等离子质谱分析了中国江西省龙南县轻、重稀土矿区和非矿区铁芒萁植物体内的稀土元素含量,并采用透射电子显微镜对其叶片细胞内的稀土元素进行精确定位。还比较系统的研究了自然条件下的铁芒萁与高浓度稀土元素处理条件下的非稀土元素富集植物黄瓜(Cucumis sativus Linn)的光合特性。结果表明: 1、0.5 mmol•L-1 LaCl3处理黄瓜后,可以诱导激发能向PS II分配。1和2 mmol•L-1 LaCl3处理黄瓜后,对黄瓜幼苗抑制作用表现在对其生长率,光合放氧活性和叶绿体完整率的抑制。这是由于LaCl3对黄瓜细胞结构和叶绿体膜结构的破坏所致。其表现为对类囊体膜结构的破坏,而导致PS II光合活性下降,并最终抑制黄瓜生长。 2、铁芒萁可以富集稀土元素,轻、重稀土矿区铁芒萁植物稀土元素的分布规律为叶片>根>土壤>茎>叶柄,非矿区铁芒萁植物稀土元素的分布规律为叶片>根>茎>叶柄。稀土元素在铁芒萁体内的运输和迁移过程中,发生了明显的分异作用,茎、叶柄、叶片中的重稀土相对贫乏,叶片中可以富集高浓度的轻稀土元素。 3、稀土元素可以进入完整的铁芒萁表皮细胞和叶肉细胞中,但多以沉淀的形式聚集在一起。非矿区铁芒萁叶绿体中的稀土元素含量约占其叶片中含量的5%。轻稀土矿区铁芒萁叶绿体中的稀土元素含量约占其叶片中含量的10%。部分稀土元素定位于富含PS II的基粒片层上。 4、铁芒萁富集稀土元素受环境和遗传特性的双重影响,但主要由其自身的生理、生化特性决定。其富集稀土元素的机制是隔离稀土元素在细胞壁、液泡中和分泌结合物质使稀土元素成为沉淀沉积下来,从而避免对光合活性的破坏。 5、与非矿区铁芒萁相比,轻稀土矿区植物叶绿体膜的全链电子传递速率增加了34.9%,PS II的电子传递活性增高了252.9%,PS I的电子传递活性增加了16.8%。轻稀土矿区铁芒萁全链电子传递活性的增加主要来自PS II电子传递活性的大幅提高,这可能与其调节激发能更多向PS II分配,提高PS II反应中心色素蛋白复合体(67.0%)和捕光色素蛋白复合体的含量相关。 6、与非矿区铁芒萁相比,重稀土矿区植物叶绿体膜的全链电子传递速率增加了46.3%,PS II的电子传递活性增高了23.8%,PS I的电子传递活性增加了60.4%。重稀土矿区铁芒萁电子传递活性的提高主要来自PS I电子传递活性的大量增加,这可能与其PS I反应中心蛋白复合体含量的提高(60.0%)有关。 铁芒萁富集并吸收稀土元素主要是由自身的理化特性决定的。它能够将稀土元素以沉淀的形式固定在细胞内部,并通过改变生理代谢来避免高浓度稀土元素对其光合作用的影响。可以在治理稀土元素污染的环保工程中用作植物修复材料。

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Dichotomains A (1) and B (2), two new highly oxygenated phenolic derivatives that feature a spirodilactone moiety in their structures, were isolated from the fronds of Dicranopteris dichotoma. Their structures were elucidated on the basis of NMR and MS sp

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The acetone extract of Dicranopteris dichotoma afforded two new tetranorclerodanes, 18-hydroxyaylthonic acid (1) and 18-oxo-aylthonic acid (2), and four new clerodane-type diterpene glycosides, (6S,13S)-6-O-[6-O-acetyl-beta-D-glucopyranosyl-(1 -> 4)-alpha

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In recent years, sulfated polysaccharides from marine algae have emerged as an important class of natural biopolymers with potential application in human and veterinary health care, while taking advantage of the absence of potential risk of contamination by animal viruses. Among these, fucans isolated from the cell walls of marine brown alga have been study due to their anticoagulant, antithrombotic, anti-inflammatory and antiviral activities. These biological effects of fucans have been found to depend on the degree of sulfation and molecular size of the polysaccharide chains. In the present study, we examined structural features of a fucan extracted from brown alga Dictyota menstrualis and its effect on the leukocyte migration to the peritoneum. The sulfated polysaccharides were extracted from the brown seaweed by proteolytic digestion, followed by sequential acetone precipitation producing 5 fractions. Gel lectrophoresis using 0.05 M 1,3-diaminopropane-acetate buffer, pH 9.0, stained with 0.1% toluidine blue, showed the presence of sulfated polysaccharides in all fractions. The chemical analyses demonstrated that all fractions are composed mainly of fucose, xylose, galactose, uronic acid, and sulfate. Electrophoresis in agarose gel in three different buffers demonstrated that the fraction 2.0v have only one population of fucan. This compound was purify by exclusion molecular. It has shown composition of fucose, xilose, sulfate and uronic acid in molar ration of 1.0: 1.7: 1.1: 0.5 respectively. The effect of this heterofucan on the leukocyte migration was observed 6h after zymozan (mg/g) administration into the peritoneum. The heterofucan showed higher antimigratory activity, it decrease the migration of leukocyte in 83.77% to peritoneum. The results suggest that this fucan is a new antimigratory compound with potential pharmacological appications

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In the present study, extracts rich-sulfated polysaccharides were obtained from three different species of Dictyotales (a class of brown macroalgae): Canistrocarpus cervicornis, Dictyota mertensii and Dictyopteris delicatula and their anticoagulant and antioxidant activities were evaluated. All extracts showed anticoagulant activity on aPTT assay, but not on PT assay. Extracts also exhibited total antioxidant activity, superoxide radical scavenging capacity and ferric chelating property. The extract from C. cervicornis showed the best results and was choose to have their sulfated polysaccharides fractioned and subsequently analysed. Thus, six fractions (CC-0.3, CC-0.5, CC-0.7, CC-1.0, CC-1.2 and CC-2.0) were obtained by proteolysis followed by sequential acetone precipitation. Agarose gel eletrophoresis stained with blue toluidine, confirmed the presence of sulfated polysaccharides in all fractions. Chemical analyses showed that all fractions presented heterofucans mainly constitued by fucose, galactose, glucuronic acid and sulfate. Any fraction changed the PT. However, all fractions were able to double the aPTT on a dose-dependent manner. CC- 0.3, CC-0.5, CC-0.7 and CC-1.0 needed only 0.100 mg/mL to double the aPTT, result only 1.25 times higher than the Clexane® (0.080 mg/mL), a commercial low molecular heparin. The heterofucans presented appreciable total antioxidant capacity, low capacity on scavenging hydroxyl radical and good efficiency on scavenging superoxide radicals (except CC-1.0). CC-1.2 showed 43.1 % on superoxide radical scavenging. This result was higher than that showed by the same concentration of gallic acid (41.8 %), a known antioxidant. Furthermore, the heterofucans showed excelent activity on ferrous chelating activity (except CC-0.3). CC-0.5, CC-0.7 and CC-1.0 showed the highest activities with 47.0 % of ferrous chelating activity, a result 2.0 times lesser than that exhibited by the same concentration of EDTA. These results clearly indicated the beneficial effects of heterofucans extracted from C. cervicornis as potential anticoagulant and antioxidant agents. However additional steps of purification, structural studies, besides in vivo experiments are needed for these fucans may be used as therapeutic agents

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Seaweeds are a major source of biologically active compounds . In the extracellular matrix of these organisms are sulfated polysaccharides that functions as structural components preventing it against dehydration. The fraction 0.9 (FucB) rich in sulfated fucans obtained from brown seaweed Dictyota menstrualis was chemical characterized and evaluated for pharmacological activity by testing anticoagulant activity, stimulatory action on the synthesis of an antithrombotic heparan sulfate, antioxidant activity and its effects in cell proliferation. The main components were FucB carbohydrates (49.80 ± 0.10 %) and sulfate (42.30 ± 0.015 %), with phenolic compounds ( 3.86 ± 0.016 %) and low protein contamination ( 0.58 ± 0.001 % ) . FucB showed polydisperse profile and analysis of signals in the infrared at 1262, 1074 and 930 cm -1 and 840 assigned to S = O bonds sulfate esters , CO bond presence of 3,6- anhydrogalactose , β -D- galactose non- sulfated sulfate and the axial position of fucose C4 , respectively. FucB exhibited moderate anticoagulant activity , the polysaccharides prolonged time (aPTT ) 200 ug ( > 90s ) partial thromboplastin FucB no effect on prothrombin time (PT), which corresponds to the extrinsic pathway of coagulation was observed. This stimulation promoted fraction of about 3.6 times the synthesis of heparan sulfate (HS) by endothelial cells of the rabbit aorta ( RAEC ) in culture compared with cells not treated with FucB . This has also been shown to compete for the binding site with heparin. The rich fraction sulfated fucans exhibited strong antioxidant activity assays on total antioxidant (109.7 and 89.5 % compared with BHT and ascorbic acid standards ) , reducing power ( 71 % compared to ascorbic acid ) and ferric chelation ( 71 , comparing with 5 % ascorbic acid). The fraction of algae showed cytostatic activity on the RAEC cells revealed that the increase of the synthesis of heparan sulfate is not related to proliferation. FucB showed antiproliferative action on cell lines modified as Hela and Hep G2 by MTT assay . These results suggest that FucB Dictyota menstrualis have anticoagulant , antithrombotic , antioxidant potential as well as a possible antitumor action, promoting the stimulation of the synthesis of antithrombotic HS by endothelial cells and is useful in the prevention of thrombosis, also due to its inhibitory action on species reactive oxygen ( ROS ) in some in vitro systems , being involved in promoting a hypercoagulable state

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Fucana é um termo que define uma família de hetero e homopolissacarídeos que contem L-fucose em sua estrutura. Neste trabalho uma hererofucan F 2,0v da alga Dictyota menstrualis foi avaliada como agente antinociceptivo e antiinflamatório. A fucana F 2,0v inibiu a migração de leucócitos em até 100% (20.0 mg/kg) para a cavidade peritoneal após estimulo químico, porém, não alterou a expressão das interleucinas IL-1β, IL-6 e de TNF-α. Com relação a sensação dolorosa a F 2,0v (20.0 mg/kg) possui atividade antinociceptiva periférica com potência semelhante à dipirona. Por outro lado não apresentou efeito no teste da placa quente. Análises de microscopia confocal e citometria de fluxo mostram que a F 2,0v se liga a superfície dos leucócitos. O conjunto de resultados apresentados pela fucana F 2,0v sugerem que o mecanismo de ação está relacionado com sua capacidade de inibir a migração de leucócitos para o local da injúria tecidual. Em resumo os dados mostram que F 2,0v apresenta grande potencial como composto antinociceptivo e antiinflamatório. Estudos futuros serão realizados para caracterizar melhor o mecanismo de ação da F 2,0v