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1
Gornard, Sophie. "Isolement et caractérisation de bactéries marines associées à l'algue brune Ascophyllum nodosum pour la dépolymérisation enzymatique du fucane." Paris 13, 2002. http://www.theses.fr/2002PA132031.
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Le fucane, constitué de L-fucose sulfaté, est extrait d'algues brunes. Depuis 1987, ce polysaccharide bioactif est étudié par le Laboratoire de Recherches sur les Macromolécules (CNRS, Université Paris 13) et le Centre IFREMER de Nantes dans le cadre de l'unité de Recherche marine n°2. A l'heure actuelle, ses propriètés n'ont jamais étè exploitées à des fins thérapeutiques en raison du manque de connaissance de sa structure fine et des mécanismes moléculaires gouvernant ses activités. L'objectif de ce travail était de développer une approche enzymatique pour la caractérisation de sa structure. Le Centre d'étude et de Valorisation des Algues, désireux de développer un pôle de production d'oligosaccharides, a mis ses moyens techniques à la disposition de ce projet de recherche d'enzymes bactérienne de dégradation du fucane. Nos travaux ont permis de disposer de deux bactéries associées à l'algue Ascophyllum nodosum, nommées B et C, capables de dégrader le fucane. Après optimisation de leurs conditions de culture et de stockage, ces bactéries ont été caractérisées comme appartenant à la famille des Flavobacteriaceae. Elles représentent deux nouvelles espèces bactériennes. Ces bactéries sont capables de produire une activité sulfatase et des fucanases extracellulaires. L'activité fucanase de la bactérie B aurait un mécanisme exolytique et l'activité fucanase de la couche C serait endolyptique. Le niveau d'activité des enzymes extracellulaires étant relativement faible, nous avons recherché des enzymes intracellulaires et périplasmiques chez la souche C. Les résultats obtenus nous ont laissé penser que l'activiité fucanase de cette bactérie serait intracellulaire et pourrait même avoir une localisation périplasmique. La caractérisation des enzymes mises en évidence doit être poursuivie. En effet, ces enzymes purifiées devraient s'avérer utile dans la compréhension des propriètés biologiques du fucane et permettre une modification selective du polysaccharideFucan constituted of sulfated L-fucose is extracted from brown seaweeds. Since 1987, this bioactive polysaccharide is studied by the Unity of Marine research n°2 constituted of the Research Laboratory on Macromolecules (CNRS, Paris 13) and IFREMER (Nantes). Currently its properties have never been used for therapeutic purposes. This is partly due to the lack of knowledge about its fine structure and moleculary mecanisms responsible for its activities. The aim of this work was to develoop enzymes for the characterisation of the structure of fucan. The Seaweed Manufacturing Technology Center, inclined to diversify its production of oligosaccharides, made its technical means available for this research about bacterial enzymes able to degrade fucan. Our research enable us to find two bacteria called B and C and associated to the brown seaweed Ascophyllum nodosum, able to degrade fucan. We optimized their culture conditions and their storage. Then we found that these bacteria belonging to the Flavobacteriaceae correspond to two new bacterial species. These bacteria produce an extracellular sulfatase activity and extracellular enzymes responsible for fucan degradation. The fucanase activity of the bacteria B could have an exolytic mecanism and the fucanase activity of the bacteria C could be endolytic. The grade of activity of the extracellular enzymes was low. So we look for intracellular and periplasmic enzymes associated to the bacteria C. The results let us thinks that the fucanase activity of this bacteria could be intracellular and could have a periplasmic localisation. The characterisation of these enzymes should be continued. The purified enzymes should indeed be useful for the understanding of biological properties of the fucan. They could also enable a selective depolymerisation of this polysaccharide
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Dantas, Viviane Wallerstein Mignone. "Papel da fucana sulfatada FucSulf I na interação entre células tumorais e o endotélio in vitro." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5993.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoPara formar metástases, as células tumorais devem se desprender do tumor primário e migrar através do endotélio num processo denominado intravasamento. Uma vez na circulação, elas devem aderir ao endotélio do tecido alvo e extravasar para o novo sítio de colonização, onde irão proliferar. A interação das células tumorais com o endotélio é mediada por selectinas, seguida pela interação com integrinas. As células tumorais apresentam um padrão anormal de glicosilação, expressando ligantes de selectinas, formados por polissacarídeos fucosilados, como sialyl Lewis a/x. Durante o processo metastático, células tumorais secretam diversos fatores de crescimento. Além de modular diferentes tipos celulares que constituem o microambiente tumoral, estes fatores de crescimento também atuam nas células tumorais de forma autócrina, ativando vias de sinalização envolvidas na proliferação e migração celular. Polissacarídeos sulfatados como a heparina, podem atuar como inibidores de P e L-selectinas, além de se ligar a fatores de crescimento, impedindo a ativação de seus receptores. Neste trabalho, avaliamos o papel de fucanas sulfatadas extraídas de diferentes espécies de invertebrados marinhos (L. variegatus, S. franciscanus, S. pallidus, A. lixula e S. droebachiensis) na modulação da interação entre células tumorais com o endotélio in vitro e comparamos seu efeito com o da heparina. Também avaliamos o papel destas moléculas na proliferação de células tumorais. Para isso, utilizamos duas linhagens tumorais de próstata (DU-145 e PC-3) e culturas primárias de células endoteliais de veia umbilical humana (HUVECs). Ao avaliar o efeito das fucanas na adesão das células tumorais às HUVECs, observamos que todas as fucanas testadas inibiram a adesão da linhagem DU-145 à monocamada endotelial, enquanto apenas a fucana extraída da espécie L. variegatus (FucSulf I) e da espécie S. franciscanus inibiram a adesão da linhagem PC-3. A FucSulf I foi uma das fucanas que apresentou maior potencial inibitório nas duas linhagens e foi a única que inibiu a adesão da linhagem DU-145 à matriz subendotelial, não interferindo na adesão da linhagem PC-3. A FucSulf I mostrou-se capaz de diminuir também a migração transendotelial das linhagens tumorais DU-145 e PC-3. A heparina mostrou efeito significativo apenas nos ensaios de transmigração, inibindo este evento de forma similar a FucSuf I. Sabe-se que o VEGF aumenta a permeabilidade endotelial, facilitando a passagem de células tumorais através do vaso. Observamos que as duas linhagens secretam VEGF e que a FucSulf I se liga a este fator. Estes dados sugerem que a interação da FucSuf I com o VEGF pode impedir a ação deste fator nas células endoteliais, diminuindo a migração transendotelial das células tumorais testadas. Também verificamos que a FucSulf I inibiu a proliferação das linhagens celulares na ausência de fatores exógenos ou na presença de soro fetal bovino ou VEGF. Por fim, avaliamos que a FucSulf I interfere na ativação de proteínas específicas de vias de sinalização disparadas por fatores de crescimento. A FucSulf I inibe a ativação da AKT na linhagem PC-3, enquanto nas células DU-145 observamos uma inibição da ativação da ERK. Esses dados indicam que a FucSulf I modula diversas etapas da progressão tumoral e pode ser um potencial candidato para o uso em terapias antitumorais
To form metastasis, tumor cells must detach from primary tumor and migrate through the endothelial cell monolayer in direction of the bloodstream (intravasation). Once in the circulation, tumor cells must be able to adhere and migrate across the endothelium (extravasation) towards the target organ, where they will proliferate. Interaction between endothelial and tumor cells is mediated by selectins, followed by the interaction with integrins. Cancer cells frequently exhibit abnormal glycosylation patterns, resulting in the expression of selectins ligands formed by fucosylated polysaccharides, such as sialyl Lewis a/x. During metastatic process, tumor cells secrete several growth factors which can modulate different cell types that are present in the tumor microenvironment. These growth factors can also mediate autocrine signaling and activate signaling pathways involved in tumor cell proliferation and migration. Sulfated polysaccharides, as heparin, may act as P and E-selectin inhibitors as they may also bind to growth factors and interfere in their receptor activation. In this present work, we evaluated the role of sulfated fucans extracted from different marine invertebrates species (L. variegates, S. franciscanus, S. pallidus, A. lixula e S. droebachiensis) in the modulation of the interaction between tumor and endothelial cells in vitro and compared their effect with heparin. We also investigated the role of these molecules in the proliferation of tumor cells. For that, we used two prostate tumor cell lines (DU-145 and PC-3) and a primary culture of human umbilical vein endothelial cells (HUVECs). We first evaluated the effect of the fucans in the tumor cell adhesion to HUVECs. All fucans tested were able to inhibit the interaction between DU-145 and the endothelial cells, while only fucans extracted from L. variegates (FucSulf I) and S. franciscanus were able to inhibit the adhesion of PC-3. FucSulf I showed one of the most striking inhibitory effects in both cell lines and was the only one that inhibited adhesion of DU-145 to subendothelial matrix. It didnt interfere with the adhesion of PC-3 to subendothelial matrix. FucSulf I was also able to decrease transendothelial migration of DU-145 and PC-3. Heparin had significant effect only in the transmigration assays, showing a similar inhibitory potencial in comparison with FucSulf I. VEGF increases endothelial permeability, thus facilitating the migration of tumor cells through the endothelial barrier. We observed that both tumor cell lines secrete VEGF and FucSulf I binds to this factor. These data suggest that the interaction between FucSulf I and VEGF may interfere in endothelial cells response to VEGF, and decrease transendothelial migration of tumor cells. We also showed that FucSulf I inhibits tumor cell proliferation in the absence of exogenous growth factors or in the presence of fetal bovine serum or VEGF. At least, we showed that FucSulf I interfered in the activation of specific proteins involved in signaling pathways triggered by growth factors. FucSulf I inhibited the activation of AKT in PC-3 tumor cell line, while inhibited the activation of ERK in DU-145 tumor cell line. These results indicate that FucSulf I modulates several steps of tumor progression and may be a potential candidate for use in antitumor therapies
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Silva, Ana Katarina Andrade. "Efeito antiinflamat?rio de fucana extra?da da alga Parda spatoglossum schroederii em modelos experimentais de Peritonite, choque n?o s?ptico e colite." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13084.
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Previous issue date: 2012-05-17Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Fucans is a name used for sulfated polysaccharides, which is most characteristic structure of the presence of sulfated L-fucose, are found in brown seaweed (Phaeophyceae) and echinoderms (sea urchins and sea cucumbers). These polysaccharides have been reported to possess anticoagulant, antitumor, anti-viral, anti-proliferative and anti-inflammatory activities. Therefore, in the present study was evaluate the effect of the fucan from the brown seaweed Spatoglossum schroederii in models of peritonitis and non-septic shock induced by zymosan, as well as in a murine model of colitis induces by DSS. So, the mice treatment by intravenous route with the fucan was able to reduce the exudate formation and the cell migration in the model of acute peritonitis induced by zymosan during the kinetic of 6, 24 and 48 hours. Similarly, in the model of non-septic shock induced by zymosan the fucan demonstrated a protector effect to inhibited the cellular migration to the peritoneo, to decrease the levels of IL-6 in the serum and in the peritoneal exudate, to attenuate the lose of weight in the mice; beside to reduce the serum levels of hepatic transaminases and as well as the liver injury. In the model of murine colitis, the treatment with the fucan reduced the lose of weight of the animals, decreased the levels of IL-17 and IFN- produced in the gut and decrease the intestinal lesion induced by DSS. In conclusion, the fucan used in this study presented a significant protector effect in the murine models of inflammation
Fucana ? uma denomina??o utilizada para polissacar?deos sulfatados, que tem como caracter?stica estrutural mais marcante a presen?a de L-fucose sulfatada, sendo encontrados em algas pardas (Phaeophyceae) e em equinodermos (ouri?os e pepinos do mar). Esses polissacar?deos tem sido descritos por possuir atividade anticoagulante, anti-tumoral, anti-viral, antiproliferativa e anti-inflamat?ria. Portanto, no presente estudo foi avaliado o efeito da fucana da alga parda Spatoglossum schroederii em modelos de peritonite e choque n?o s?ptico induzido por zimosan, bem como em um modelo murino de colite induzida por DSS. Dessa forma, o tratamento de camundongos pela via intravenosa com a fucana foi capaz de reduzir a forma??o do exsudato e a migra??o celular no modelo de peritonite aguda induzida por zimosan durante a cin?tica de 6, 24 e 48 horas. De maneira semelhante, no modelo de choque n?o-s?ptico induzido por zimosan a fucana demonstrou efeito protetor ao inibir a migra??o celular para o perit?nio, diminuir os n?veis de IL-6 s?rico e no exsudato peritoneal, ao atenuar a perda de peso do animais, al?m de reduzir os n?veis s?ricos das transaminases hep?ticas, assim como a les?o no f?gado. No modelo murino de colite, o tratamento com a fucana reduziu a perda de peso dos animais, diminuiu os n?veis de IL-17 e IFN- produzidos no intestino e diminuiu a les?o intestinal ocasionada pela DSS. Conclui-se ent?o, que a fucana usada nesse estudo apresentou efeito protetor significativo diante dos modelos murinos de inflama??o
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Dore, Celina Maria Pinto Guerra. "Aspectos estruturais, farmacol?gicos e biol?gicos de fucanas da alga marrom sargassum vulgare." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12570.
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Previous issue date: 2012-10-15Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The present study examines the chemical composition and their effects on free radicals, inflammation, angiogenesis, coagulation, VEGF effects and cellular proliferation of a polysaccharides from alga Sargassum vulgare. The sulfated polysaccharide was extracted from brown seaweed by proteolysis with enzymes maxataze. The presence of proteins and sugars were observed in crude polysaccharides. Fractionation of this crude extract was made with growing concentration of acetone (0.3-1.5 v) and produced four groups of polysaccharides. Anionic polysaccharides from brown seaweed Sargassum vulgare, SV1and PSV1 were fractionated (SV1) and purified (PSV1), and displayed with high total sugars and sulfate content and very low level of protein. This fucan SV1 contains low levels of protein and high carbohydrate and sulfate content. This polysaccharides prolonged activated partial thromboplastin time (aPTT) at 50 μg (>240 s). SV1 was found to have no effect on prothrombin time (PT), corresponding to the extrinsic pathway of coagulation. SV1 exhibits high antithrombotic action in vivo, with a concentration ten times higher than heparin. Polysaccharides from S. vulgare promoted direct inhibition enzymatic activity of thrombin and stimulated enzymatic activity of FXa. SV1 showed optimal inhibitory activity of thrombin (50.2?0.28%) at a concentration of 25 μg/mL. Its antioxidant action on scavenging radicals by DPPH was (22%), indicating the polymer has no cytotoxic action (hemolytic) on ABO and Rh blood types in different erythrocyte groups and displays strong anti-inflammatory action on all concentrations tested in the carrageenan-induced paw edema model, demonstrated by reduced edema and cellular infiltration. Angiogenesis is a dynamic process of proliferation and differentiation. It requires endothelial proliferation, migration, and tube formation. In this context, endothelial cells are a preferred target for several studies and therapies. The antiangiogenic efficacy of polysaccharides was examined in vivo in the chick chorioallantoic membrane (CAM) model by using fertilized eggs. Decreases in the density of the capillaries were assessed and scored. The results showed that SV1 and PSV1 have an inhibitory effect on angiogenesis. These results were also confirmed by inhibition tubulogenesis in rabbit aorta endothelial cell (RAEC) in matrigel. These compounds were assessed in Apoptosis assay (Annexin V - FITC / PI) and cell viability by MTT assay of RAEC. These polysaccharides do not affect the viability and do not have apoptotic or necrotic action. RAEC cell when incubated with SV1 and PSV1showed inhibition of VEGF secretion, observed when compounds were incubated at 25, 50 and 100 μg/μL. The VEGF secretion with the RAEC cell line for 24 h, was more effective for PSV1 at 50 μg/μL(71.4%) than SV1 100 μg/μL (75.9%). SV1 and PSV1 had an antiproliferative action (47%) against tumor cell line HeLa. Our results indicate that these sulfated polysaccharides have antiangiogenic and antitumoral actions
O presente estudo analisa a composi??o qu?mica e seus efeitos sobre os radicais livres, inflama??o, angiog?nese, coagula??o, VEGF e prolifera??o celular dos polissacar?deos de uma alga Sargassum vulgare. O polissac?rido sulfatado foi extra?do a partir de algas marrons por prote?lise com a enzima maxataze. A presen?a de prote?nas e a??cares foram observados no cru de polissacarideos. Fracionamento do o extrato bruto foi feito com concentra??es crescente de acetona (0,3-1,5 v), produzindo quatro grupos de polissacarideos. Estes compostos ani?nicos da alga S. vulgare, foram fracionados (SV1) e purificados (PSV1) exibindo com alta a??cares totais e sulfatecontent e n?vel muito baixo de prote?nas.A fucana SV1 cont?m baixos n?veis de prote?na e de hidratos de carbono e alto teor de sulfato. Este polissacar?deos prolongou o tempo de tromboplastina parcial activada (aPTT) a 50 ug (>240 s). n?o foi observado qualquer efeito de SV1 sobre o tempo de protrombina (PT), que corresponde a via extr?nseca da coagula??o. SV1 exibiu alta a??o antitromb?tica in vivo, com uma concentra??o 10 vezes maior do que a heparina. SV1 promoveu a actividade de inibi??o enzim?tica direta da trombina e estimulou a atividade enzim?tica do FXa. Mostrou tamb?m, atividade inibidora optima de trombina (50,2 ? 0,28%) a uma concentra??o de 25 ug / mL. A sua ac??o anti-oxidante de radicais scavenging por DPPH foi de (22%), indicando que o pol?mero n?o tem qualquer a??o citot?xica (hemol?tica) em tipos de sangue ABO e Rh, em diferentes grupos de eritr?citos e exibindo alta a??o anti-inflamat?ria em edema de pata de ratos Wistar em todas as concentra??es testadas induzida por carragenina. Tal processo foi demonstrado por edema e infiltra??o celular. A angiogenese ? um processo din?mico de prolifera??o e diferencia??o. Ele requer prolifera??o endotelial, migra??o, e a forma??o do tubo. Neste contexto, as c?lulas endoteliais s?o um alvo preferido para muitos estudos e terapias. A efic?cia antiangiogenico de polissacar?deos foi examinada in vivo na membrana corioalant?ica pinto (CAM) usando-se ovos fertilizados. Diminui??es na densidade dos capilares foram avaliados e pontuados. Os resultados mostraram que SV1 e PSV1 tem um efeito inibidor da angiogenese. Estes resultados foram tamb?m confirmados por tubulogenesis inibi??o na c?lula endotelial da aorta de coelho (RAEC) em matrigel. C?lulas RAEC quando foram incubadas com SV1and PSV1 demonstraram inibi??o da secre??o de VEGF, a 25, 50 e 100 ug/mL. A secre??o de VEGF com a linha de c?lulas RAEC durante 24 h, foi mais eficaz para PSV1 a 50 ug / mL (71,4%) do que SV1 100 ug / mL (75,9%). SV1 e PSV1 posuiram uma ac??o antiproliferativa (47%) contra as c?lulas tumorais tipo HeLa. Estes compostos foram avaliados tamb?m, no ensaio de apoptose (anexina V - FITC / PI) e a viabilidade celular pelo ensaio de MTT de RAEC. Estes polissacar?deos n?o afetaram a viabilidade e n?o tiveram a??o apopt?tica ou necr?tica. Nossos resultados indicam que estes polissacar?deos sulfatados t?m a??es antiangiog?nica e antitumoral e constituem um importante alvo biol?gico e farmacol?gico
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Marques, Cybelle Teixeira. "?Atividade antiinflamat?ria de uma heterofucana da alga marrom Padina gymnospora." Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/18531.
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Previous issue date: 2007-09-05Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
?Fucans, sulfated polysaccharides extracted from brown algae and some echinoderms, have been extensively studied for its diverse biological activities and because of its interference with molecular mechanisms of cell to cell recognition, including leukocyte trafficking from blood vessels into sites of inflammation mediated by selectin, a family of adhesion molecules. In the present study, we examined structural features of a heterofucan extracted from brown algae Padina gymnospora and its effect on the leukocyte migration to the peritoneum. The sulfated polysaccharides were extracted from the brown seaweed by proteolysis with the proteolytic enzyme maxatase. The presence of protein and uronic acid contamination was detected in the crude polysaccharide extract. Fractionation of the crude extract with growing concentrations of acetone produced five fractions with different concentrations of fucose, xylose, uronic acid, galactose, glucose and sulfate. The fraction precipitated with 1.5 volumes of acetone was characterized by infrared and nuclear magnetic resonance, through which can be observed the presence of sulfate groups in the C4 of -L-fucose. The anti-inflammatory action of this composite was assessed by a sodium thioglycollate-induced peritonitis assay and through nitric oxide production by the peritoneal macrophages using Griess reagent. Fraction F1.5 was efficient in reducing leukocyte influx into the peritoneal cavity when 10 mg/kg and 25mg/kg were used, resulting in a decrease of 56 and 39%, respectively. A decrease of nitric oxide production occurred when high concentrations of fucana were used. The cytotoxicity of the composite was also assessed using the reduction of 3-(4,5 dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT). Fraction F1.5 had no cytotoxicity when 500 ?g/mL of the fraction was used. This study suggests the use of fraction F1.5 (heterofucan) as an anti-inflammatory
Fucanas, polissacar?deos sulfatados extra?dos de alga marrom e alguns equinodermos, t?m sido extensivamente estudadas devido as suas diversas atividades biol?gicas e pela sua interfer?ncia com mecanismos moleculares de reconhecimento celular, incluindo o tr?fego de leuc?citos dos vasos sangu?neos para o interior de s?tios inflamat?rios mediado pela fam?lia das mol?culas de ades?o denominada selectinas. Neste presente estudo, n?s examinamos a estrutura de uma heterofucana extra?da da alga marrom Padina gymnospora e seu efeito sobre a migra??o de leuc?citos para o perit?nio. Os polissacar?deos sulfatados foram extra?dos da alga marrom por prote?lise com a enzima proteol?tica maxatase. A presen?a de contamina??o por prote?nas e ?cido ur?nico foi detectada no extrato bruto dos polissacar?deos. Fracionamento do extrato bruto com concentra??es crescentes de acetona produziu cinco fra??es com diferentes concentra??es de fucose, xilose, ?cido ur?nico, galactose, glicose e sulfato. A fra??o precipitada com 1,5 volume de acetona foi caracterizada por infravermelho e resson?ncia magn?tica nuclear, atrav?s das quais se p?de constatar a presen?a de grupos sulfato no C4 da -L-fucose. A a??o antiinflamat?ria deste composto foi avaliada atrav?s do ensaio de peritonite induzida por tioglicolato de s?dio e atrav?s da produ??o de ?xido n?trico por macr?fagos peritoneais utilizando-se o reagente de Griess. A fra??o F1,5 mostrou-se eficiente na redu??o do influxo leucocit?rio para a cavidade peritoneal quando utilizados 10 mg/Kg e 25 mg/Kg resultando em uma diminui??o na ordem de 56 e 39 %, respectivamente. Uma diminui??o na produ??o de ?xido n?trico ocorreu quando altas concentra??es de fucana foram usadas. A citotoxicidade do composto tamb?m foi avaliada utilizando-se como par?metro a redu??o do 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). A fra??o F1,5 n?o apresentou citotoxicidade quando utilizados 500 ?g/ml da fra??o. Este estudo sugere o uso da fra??o F1,5 (heterofucana) como um antiinflamat?rio
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Boyen, Catherine. "Etude de la paroi cellulaire des pheophycees : approche physicochimique et immunocytologique, preparation d'enzymes de degradation specifiques." Paris 6, 1987. http://www.theses.fr/1987PA066281.
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Etude de la composition osidique d'alginate des genres pelvetia, fucus, arcophyllum, sargassum et laminaria. Preparation et caracterisation des alginates-lyases a partir de divers mollusques marins et d'une bacterie marine. Etude comparee de la regeneration de la paroi du protoplaste et de la mise en place normale de la paroi du zygote de fucus distichus par marquage avec des anticorps monoclonaux
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LIRA, Mariane Cajubá de Britto. "Estudo da utilização da Fucana como agente de direcionamento de nanopartículas para macrófagos." Universidade Federal de Pernambuco, 2009. https://repositorio.ufpe.br/handle/123456789/1322.
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Previous issue date: 2009Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco
O objetivo do presente trabalho foi inicialmente extrair e purificar o polissacarídeo fucana proveniente do Sargassum cymosum e utilizá-lo como agente de direcionamento de nanopartículas para macrófagos. A caracterização do material extraído e purificado foi efetuada utilizando análise elementar, espectroscopia de infravermelho (IV), ressonância magnética nuclear de hidrogênio (RMN H1) e análise térmica e a determinação da massa molecular foi efetuada por cromatografia de permeação em gel. Em seguida, o material obtido foi utilizado na preparação das novas nanopartículas de Poli(cianoacrilato de isobutila) revestidas de fucana (FC-PIBCA-NP). As nanopartículas foram obtidas através da polimerização por emulsão aniônica (AEP) e polimerização por radicais redox (RREP) utilizando mistura de dextrana e fucana em diferentes proporções. As nanopartículas foram caracterizadas através do tamanho, potencial zeta, morfologia e estabilidade a longo prazo. Nanopartículas estáveis foram obtidas com até 100% de fucana pelo método AEP. Por outro lado, suspensões estáveis de nanopartículas foram obtidas com no máximo 25% de fucana por RREP. As suspensões obtidas com porcentagem mais elevadas de fucana não permaneceram estáveis. O potencial zeta das nanopartículas diminuiu com o aumento da quantidade de fucana, alcançando o valor de 44 mV para as nanopartículas preparadas por AEP com 100% de fucana. Estes resultados indicam que a fucana permanece localizada na superfície das nanopartículas. A análise morfológica por microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (MET) mostrou nanopartículas com forma esférica. A estrutura interna das nanopartículas do tipo núcleo-coroa foi mostrada claramente por análise MET o que está de acordo com os resultados do potencial zeta que sugerem a localização do polissacarídeo na superfície das nanopartículas. As interações das nanopartículas com a linhagem celular de macrófagos J774 e com fibroblastos NIH-3T3 foram investigadas pela avaliação da citotoxicidade e pela observação da captura celular por microscopia confocal de fluorescência. As nanopartículas preparadas pelo método AEP mostraram uma maior citotoxicidade em macrófagos. Por exemplo, as nanopartículas obtidas pelo método AEP contendo 25% de fucana mostraram-se 3 vezes mais citotóxicas em macrófagos J774 comparadas às nanopartículas RREP (IC50 = 4 ± 2μg/mL e IC50 11 ± 3μg/mL, respectivamente). As observações efetuadas por microscopia confocal de fluorescência para avaliar a captura e a distribuição das nanopartículas nas células não permitiram explicar o aumento da citotoxicidade das nanopartículas obtidas pelo método AEP nos macrófagos. Todos os tipos de nanopartículas foram encontradas nos dois tipos de células, demonstrando que elas podem ser capturadas independentemente pelos macrófagos e fibroblastos. As diferenças na aparência da fluorescência no interior das células, i.e., pontual ou difusa, sugerem que as nanopartículas penetraram nas células por mecanismos distintos. No entanto, nenhuma correlação pode ser estabelecida entre o tipo de nanopartículas (AEP ou RREP) e o teor de fucana. As nanopartículas foram administradas em ratos por via oral com objetivo de investigar se elas poderiam ser direcionadas para os macrófagos do tecido linfóide intestinal. As propriedades bioadesivas e localização no tecido intestinal das nanopartículas fluorescentes foram investigadas por microscopia de fluorescência. Somente as nanopartículas revestidas com fucana obtidas pelo método RREP apresentaram uma redução na bioadesão comparada aos outros tipos de nanopartículas. A análise por microscopia de fluorescência revelou que as nanopartículas foram principalmente encontradas associadas ao muco residual. Apenas uma pequena quantidade de nanopartículas pôde ser visualizada na superfície das células epiteliais, do lado da luz intestinal onde estão localizadas as vilosidades e as placas de Peyer. Esses resultados sugerem a retenção das nanopartículas no muco e que uma pequena quantidade de nanopartículas chega à superfície do epitélio para ser eventualmente capturada pelos macrófagos. Embora o presente trabalho tenha permitido realizar a extração da fucana e a preparação de nanopartículas de PIBCA revestidas com fucana, não foi capaz, no entanto, de demonstrar que as novas nanopartículas podem ser utilizadas para aumentar a especificidade e direcionamento para macrófagos. Experimentos complementares serão, portanto, necessários para melhor compreender a origem da citotoxicidade das nanopartículas obtidas pelo método AEP em macrófagos J774. Além do mais, para o direcionamento das nanopartículas para macrófagos presentes em mucosas, as propriedades bioadesivas precisam ser ajustadas com vistas a reduzir a retenção pelo muco e de permitir um maior alcance na quantidade de nanopartículas a atingir a superfície das células epiteliais
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PEDEN, MICHEL. "Les medicaments issus des algues : utilisation potentielle en therapeutique humaine." Rennes 1, 1993. http://www.theses.fr/1993REN1M155.
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Blondin, Catherine. "Polysaccharides sulfatés extraits d'algues brunes : activité anticomplémentaire des fucanes." Paris 13, 1992. http://www.theses.fr/1992PA132041.
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Les fucanes sont des polysaccharides sulfatés présents dans la paroi des algues brunes ; majoritairement constitués d'unités -1,2-l-fucose-4-sulfate. Une étude antérieure de leur mécanisme d'action anticoagulante, ainsi que la réalisation de tests in vivo et ex vivo, ont permis d'envisager l'utilisation thérapeutique des fucanes, en tant qu'agent antithrombotique dans la prévention des maladies thromboemboliques. La première partie de notre étude a donc consisté à assurer que le procédé de purification des fucanes, mis en place à l'échelle pilote, était fiable et reproductible. Nous avons pour cela analyse sept lots successifs de fucanes fractionnes, d'un point de vue physicochimique (masse molaire chromatographique, teneurs en fucose, acide uronique, sulfate, oses neutres et protéines), et d'un point de vue biologique (activité anticoagulante). Les résultats nous ont permis de sélectionner un compose de masse molaire apparente 20 000 g/mol, bien défini quant à sa composition chimique et son activité anticoagulante spécifique. Dans un deuxième partie, nous avons examiné l'effet des fucanes sur le système du complément. Le complément est un système protéique complexe qui participe aux défenses immunitaires de l'organisme. Il est composé d'au moins 11 composants dont l'activation en cascade, contrôlée par 9 protéines régulatrices, est à l'origine d'activités biologiques diverses (élimination des bactéries, des virus, opsonisation, participation a la réaction inflammatoire). L'activation anarchique de ces protéines peut survenir dans certaines pathologies (glomérulonéphrites aiguës, lupus érythémateux disséminé) ou être associée à certains traitements (circulation extracorporelle, hémodialyse). L'étude que nous avons effectuée en sérum humain ou en présence de protéines purifiées, a montré que les fucanes possèdent un fort pouvoir inhibiteur de l'activation du complément, de 15 a 90 fois supérieur a celui de l'héparine. Les deux séries de 10 et 13 fractions que nous avons préparées ont été analysées, leur action s'exerce sur les deux voies d'activation du complément et dépend de la masse molaire des fractions. En système semi purifié, les fucanes inhibent la formation de la c3 convertase classique, en empêchant le clivage de la protéine c4 par la sous-unité cls et en inhibant la liaison de la protéine c2 sur le fragment c4b. A même concentration pondérale que l'héparine, ils inhibent la formation des c3 convertases alternes, en inhibant de façon compétitive la liaison de la protéine b sur le fragment c3b. Quand la c3 convertase est stabilisée par la properdine, les fucanes, mieux que l'héparine, catalysent la dissociation des complexes c3bbbp ce qui suggère un effet direct de ces polyanions sur la properdine.
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Siméon, Amandine. "Localisations et rôles des polysaccharides de paroi au cours du développement de deux modèles d’algues brunes : le zygote de Fucus et Ectocarpu." Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS233.pdf.
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La paroi des algues brunes constitue un compartiment cellulaire majeur impliqué dans de nombreuses réponses physiologiques dont la croissance cellulaire, le développement, ou encore dans l’adaptation aux variations physico-chimiques de l’environnement. Tout comme d’autres organismes photosynthétiques (plantes, algues rouges et vertes), les algues brunes ont une paroi essentiellement composée de polysaccharides, mais compte-tenu des distances phylogénétiques, les composés sont distincts, avec nottament des alginates et des fucanes sulfatés. La majorité des connaissances sur ces compositions dérive d’extractions chimiques effectuées sur des algues entières, au cours desquelles l’information cellulaire est perdue. Aujourd’hui, des anticorps monoclonaux spécifiques d’alginates et de fucanes d’algues brunes ont été développés et caractérisés. Ces outils peuvent être utilisés pour localiser précisément à un niveau cellulaire et tissulaire des fractions polysaccharidiques particulières. Outre des informations sur la structure et la composition de la paroi, ces anticorps permettent d’étudier les rôles de ces polysaccharides dans de nombreuses réponses physiologiques, dont le développement. Afin d’étudier ces aspects, deux organismes modèles d’algues brunes, le zygote de Fucus et les sporophytes d’Ectocarpus ont été utilisés. Lors de cette thèse, des glycoprotéines minoritaires, des AGPs (arabino-galactanes protéines) ont été mises en évidence dans la paroi des algues brunes avec des fonctions majeures dans l’embryogénèse chez Fucus. L’utilisation de nos anticorps monoclonaux spécifiques a permis de montrer la dynamique de la mise en place des alginates et des fucanes au cours du développement de nos modèles. J’ai ainsi pu montrer l’implication des fucanes dans la croissance apicale et le rôle crucial du sulfate présent dans l’environnement, dans ce processusThe cell wall of brown algae is a major cell compartment involved in many physiological responses including cell growth, development, or in adaptation to the physico-chemical changes of the environment. Like other photosynthetic organisms (plants, red and green algae), brown algae have a cell wall mainly composed of polysaccharides, but taking into account phylogenetic distances, the compounds are distinct, with notably alginates and sulfated fucans. Most knowledge on cell wall compositions comes from chemical extractions carried out on whole algal plants, with the induced lost of most cellular information. Today, monoclonal antibodies specifically dericted against alginates and sulfated fucans have been developed and characterized. These tools can be used to precisely localize at a cellular and tissue level their particular polysaccharide fractions. In addition to the information on the structure and composition of the cell wall, these antibodies allow to study the biological roles of the cell wall in many functional responses, including during early development. In this study, two model organisms of brown algae, the zygote of Fucus and the sporophytes of Ectocarpus, were used. In term of cell wall composition, glycoproteins known as arabinogalactan proteins (AGPs) have been identified as minor components in the cell walls of brown algae. They were shown to have a functional role in the Fucus embryogenesis. The use of our specific monoclonal antibodies allowed to locate alginates and fucans in cell walls during the development of our models. Notably, I have shown the involvement of sulfated fucans in normal apical growth and the crucial role of sulfate in this process
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Luyt, Charles-Edouard. "Ischemie critique : nouvelles perspectives thérapeutiques." Paris 7, 2004. http://www.theses.fr/2004PA077120.
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MELO, Audenes de Oliveira. "Avaliação da atividade gastroprotetora da fucana livre e nanoencapsulada em lipossomas." Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/10530.
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O objetivo deste trabalho foi encapsular a fucana (Sargassum cymosum), em lipossomas e avaliar a atividade gastroprotetora, tanto na sua forma livre, como encapsulada. Os lipossomas foram obtidos e caracterizados por testes físico-químicos e de estabilidade. A atividade gastroprotetora in vivo foi realizada utilizando ratos Wistar, pré-tratados durante 14 dias com a fucana livre (Fuc), nanoencapsulada (Lipo- Fuc), e com os controles positivo (sem úlcera) e negativo (com úlcera e sem tratamento), por via oral. Após jejum (48 horas), a úlcera foi induzida com ácido acetilsalisílico (200 mg/Kg), o estômago e o duodeno foram removidos para análises histológicas avaliando-se a área com muco, espessura do epitélio glandular e vilosidades intestinais. Os resultados foram analisados pelos testes t-Student e Kruskal-Wallis. Lipossomas contendo fucana foram obtidos apresentando tamanho médio de partícula de 125,9 ± 1,2 nm, com índice de polidispersão 0,39 ± 0,02 e pH 6,89 ± 0,05 e carga positiva, permanecendo estáveis por 30 dias. Em relação à área de muco no estômago, os resultados mostraram que, no grupo pré-tratado com a Fuc, os animais permaneceram com média da área de muco semelhante ao grupo que não foi realizada indução da úlcera (7,5 ± 4,5 μm2 e 9 ± 6,7 μm2, respectivamente). Por outro lado, a fucana encapsulada exibiu uma área (2,6 ± 1,6 μm2) similar ao grupo com úlcera não tratada (3,5 ± μm2), sugerindo que o composto possivelmente não foi liberado a partir das vesículas no estômago, não promovendo, portanto nenhuma ação. No estudo dos danos epiteliais o grupo da Fuc apresentou valores superiores aos demais grupos tratados revelando novamente sua ação gastroprotetora. As análises no duodeno revelaram uma área média de 7,52 ± 2,42 μm2 para um epitélio normal (sem úlcera), 6,00 ± 3,17 μm2 para o epitélio com úlcera sem tratamento, 6,43 ± 1,82 μm2 e 6,62 ± 1,31 μm2 para epitélio com úlcera após tratamento com a fucana livre e encapsulada, respectivamente. Neste local, pode ser observado valor maior para tratamento com a Lipo-Fuc quando comparado ao obtido na Fuc, sugerindo que houve liberação da fucana a partir dos lipossomas, ao contrário do encontrado no estômago. Em relação à análise das vilosidades intestinais a fucana encapsulada exerceu uma atividade citoprotetora com uma extensão média de 395,53 ± 118,64 μm, inferior ao grupo com o composto livre, mas superior ao grupo referente ao controle negativo, o qual apresentou uma área de 314,10 ± 59,71 μm. Os resultados revelaram ação gastroprotetora da fucana (Sargassum cymosum), até então nunca estudada fornecendo subsídios para novas pesquisas utilizando esta molécula.
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Smelt, Kathryn Helena. "Synthesis of L-fucose analogues." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362080.
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Santos, Nednaldo Dantas dos. "Identifica??o e avalia??o de propriedades de polissacar?deos sulfatados de diferentes fontes naturais que possibilitem sua aplicabilidade biotecnol?gica." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13241.
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Previous issue date: 2012-03-19Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Sulfated polysaccharides (SP) are widely distributed in animals and seaweeds tissues. These polymers have been studied in light of their important pharmacological activities, such as anticoagulant, antioxidant, antitumoral, anti-inflammatory, and antiviral properties. On other hand, SP potential to synthesize biomaterials like as nanoparticules has not yet been explored. In addition, to date, SP have only been found in six plants and all inhabit saline environments. However, the SP pharmacological plant activities have not been carrying out. Furthermore, there are no reports of SP in freshwater plants. Thus, do SP from marine plants show pharmacological activity? Do freshwater plants actually synthesize SP? Is it possible to synthesize nanoparticles using SP from seaweed? In order to understand this question, this Thesis was divided into tree chapters. In the first chapter a sulfated polysaccharide (SPSG) was successfully isolated from marine plant Halodule wrightii. The data presented here showed that the SPSG is a 11 kDa sulfated heterogalactan contains glucose and xylose. Several assays suggested that the SPSG possessed remarkable antioxidant properties in different in vitro assays and an outstanding anticoagulant activity 2.5-fold higher than that of heparin Clexane? in the aPTT test; in the next chapter using different tools such as chemical and histological analyses, energy-dispersive X-ray analysis (EDXA), gel electrophoresis and infra-red spectroscopy we confirm the presence of sulfated polysaccharides in freshwater plants for the first time. Moreover, we also demonstrate that SP extracted from E. crassipes root has potential as an anticoagulant compound; and in last chapter a fucan, a sulfated polysaccharide, extracted from the brown seaweed was chemically modified by grafting hexadecylamine to the polymer hydrophilic backbone. The resulting modified material (SNFuc) formed nanosized particles. The degree of substitution for hydrophobic chains of 1H NMR was approximately 93%. SNFfuc-TBa125 in aqueous media had a mean diameter of 123 nm and zeta potential of -38.3 ? 0.74 mV, measured bydynamic light scattering. Tumor-cell (HepG2, 786, H-S5) proliferation was inhibited by 2.0 43.7% at SNFuc concentrations of 0.05 0.5 mg/ mL and RAEC non-tumor cell line proliferation displayed inhibition of 8.0 22.0%. On the other hand, nanogel improved CHO and RAW non-tumor cell line proliferation in the same concentration range. Flow cytometric analysis revealed that this fucan nanogel inhibited 786 cell proliferation through caspase and caspaseindependent mechanisms. In addition, SNFuc blocks 786 cell passages in the S and G2-M phases of the cell cycle
Os polissacar?deos sulfatados (PS) s?o amplamente distribu?dos em animais e tecidos de algas. Estes pol?meros t?m sido estudados em fun??o da import?ncia de suas atividades farmacol?gicas, tais como: anticoagulante, antioxidante, antitumoral, anti-inflamat?ria e as propriedades antivirais. Contudo, o potencial dos PS para sintetizar biomateriais, tais como nanopart?culas, ainda ? pouco explorado. At? ent?o, os PS s? foram encontrados em seis plantas e todas habitam ambientes salino. N?o havendo relatos de PS em plantas de ?gua doce. O que nos levou aos seguintes questionamentos: Os PS extraidos de vegetais marinhos n?o apresentam atividades farmacol?gicas? Os vegetais de ?gua doce realmente sintetizam PS? ? poss?vel sintetizar nanopart?culas utilizando PS a partir de algas marinhas? Para melhor entender as quest?es, esta tese foi dividida em tr?s cap?tulos. No primeiro cap?tulo, um polissacar?deo sulfatado (SPSG) foi isolado a partir de um vegetal marinho Halodule wrightii. Os dados aqui apresentados mostram que o SPSG ? uma heterogalactana sulfatada de 11 kDa constituida de glucose e xilose. Os ensaios realizados sugerem que o SPSG possue propriedades antioxidantes not?veis em diferentes ensaios in vitro e uma excelente actividade anticoagulante de 2,5 vezes mais elevadas do que a de heparina Clexane ? no teste APTT. No cap?tulo seguinte, utilizando ferramentas diferentes, tais como an?lises qu?micas e histol?gicas, an?lise de dispers?o de raios-X (EDXA), eletroforese em gel e espectroscopia de infra-vermelho,confirmamos, em primeira m?o, a presen?a de polissacar?deos sulfatados em vegetais de ?gua doce. Al?m de demonstrarmos que o PS extra?do a partir da raiz de E. crassipes tem potencial como um composto anticoagulante.No ?ltimo cap?tulo uma fucana, um polissac?rido sulfatado, extra?do a partir de uma alga marrom, foi quimicamente modificada por adi??o de hexadecilamina ? cadeia principal do pol?mero hidrof?lico. O material resultante (SNFuc) forneceu part?culas nanom?tricas. O grau de substitui??o para as cadeias hidrof?bicas de 1H RMN foi de aproximadamente 93%. SNFuc em meios aquosos tinha um di?metro m?dio de 123 nm e potencial zeta de -38,3 ? 0,74 mV. Os ensaios com c?lulas tumorais (HepG2, 786, H-S5) demonstrou a ocorr?ncia de uma inibi??o que variou de 2,0-43,7% em concentra??es diferentes de SNFuc (0,05-0,5 mg / mL) resultado semelhante foi obtido com a RAEC monstrando uma inibi??o entre 8,0-22,0%. Por outro lado, o nanogel estimulou a prolifera??o de linhagens celulares n?o tumorais como CHO e RAW nas mesmas concentra??es. An?lise por citometria de fluxo revelou que este nanogel de fucana inibiu a prolifera??o celular de 786 por mecanismos dependentes e independentes de caspases. Al?m disso, bloqueou a passagens da c?lula 786 na fase S e G2-M do ciclo celular
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Silva, Valdeene Albuquerque Jansen da. "Fucana magnetizada como suporte para imobilização de enzimas aplicadas na coagulação do leite." Universidade Federal de Pernambuco, 2008. https://repositorio.ufpe.br/handle/123456789/1409.
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Previous issue date: 2008Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco
O polissacarídeo fucana extraído da alga Sargassum cymossum foi magnetizado e posteriormente usado como suporte para imobilização de enzimas coaguladoras do leite. A caracterização básica da enzima imobilizada foi realizada pela determinação da temperatura ótima, estabilidade térmica, influência do cloreto de cálcio na atividade coagulante do leite, re-uso e estocagem. O método de imobilização mostrou-se adequado, apresentando uma retenção em proteína de 80% e 78% para as duas enzimas testadas, quimosina bovina e quimosina bovina recombinante, respectivamente. A atividade coagulante do leite nestes DEIs (Derivados Enzimáticos Imobilizados) foi 11,8 U/mL e 1,33 U/mL, respectivamente para as quimosinas bovina e recombinante. As temperaturas ótimas encontradas foram 60ºC (36 U/mL) e 50ºC (3,53 U/mL) para as quimosinas bovina e recombinante imobilizadas, respectivamente. Experimentos de estabilidade térmica revelaram que ambas as enzimas imobilizadas foram mais sensíveis à temperatura quando comparadas as enzimas livres. A perda da atividade com relação à enzima livre foi 66,35% para quimosina bovina após 30 minutos a 35º C, e 16,54% para recombinante após 30 minutos a 35º C. A influência do CaCl2 na atividade coagulante do leite foi comprovada tanto para as enzimas livres quanto para as imobilizadas. Na ausência do cálcio, as enzimas livres perderam 91,85% e 71,43%, respectivamente para a quimosina bovina e recombinante, enquanto que as enzimas imobilizadas não exibiram nenhuma atividade coagulante do leite. Nos testes de reuso foi observada uma perda na atividade de 80% e 60%, respectivamente para as quimosinas bovina e recombinante, após o segundo reuso
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Nardella, Alain. "Recherche d'un nouvel agent antithrombotique extrait d'algues brunes : Les fucanes. Structures et propriétés." Paris 13, 1995. http://www.theses.fr/1995PA132036.
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La recherche de nouveaux agents anticoagulants et antithrombotiques à montré le rôle prépondérant des polysaccharides sulfates. Parmi ceux ci, les fucanes sous produits de l'industrie des alginates présentent un intérêt particulier. Ces composés susceptibles d'être utilisées en remplacement de l'héparine, agent anticoagulant actuellement prescrit dans la prophylaxie et le traitement des maladies thromboemboliques, présentent en effet l'avantage d'être exempts de risque de contamination virale et n'induisent pas les effets secondaires associés à l'héparinothérapie. Ils sont extraits en quantité importante de la paroi des algues brunes. Cette famille hétérogène de polymères de haute masse molaire est constituée de trois grands groupes, les sargassanes, les ascophyllanes et les fucoïdanes. Ces derniers sont formés par l'enchainement d'unités 1-2 ou 1-3 l-fucose sulfatées. Ils présentent de bonnes activités anticoagulantes et antithrombotiques qui permet d'envisager leur éventuelle utilisation en remplacement de l'héparine. Décrites pour la première fois il y a une trentaine d'années par une équipe américaine, ces activités anticoagulantes ont fait l'objet de travaux visant à les optimiser. Divers procédés chimiques (dépolymérisation radicalaire, hydrolyse acide) et méthodes de fractionnement (chromatographie par perméation sur gel, chromatographie d'échange d'ions) ont été mis au point pour préparer des fractions de faible masse molaire à partir du fucane natif présentant une faible activité anticoagulante et une bonne activité antithrombotique. Les fractions obtenues ont des masses molaires comprises entre 3 000 et 10 000 g/mol. L'activité anticoagulante et antithrombotique de ces différents produits a été évaluée en fonction de leur teneur respective en acide uronique, en fucose et ose neutre et en fonctions sulfates. Les meilleurs résultats ont été obtenus pour des polysaccharides très sulfatés (1,5 moles de sulfate/mole hexose) et avec une masse molaire minimum de 8 000 g/mol dont la structure moléculaire se rapproche de celle d'un fucoïdane pur. Ils présentent un mécanisme d'action original sur le système de la coagulation sanguine différent de celui de l'héparine et du sulfate de dermatan. Parce qu'ils sont 30 fois moins actifs, ils ne présentent pas les risques hémorragiques de l'héparine. L'activité antithrombotique a été étudiée sur une thrombose veineuse de type wessler, induite par injection de facteur xa (chez le lapin) ou de thromboplastine (chez le singe). Malgré les bons résultats obtenus la solubilité trop faible des fucanes n'a cependant pas permis à ce stade d'aboutir à un substitut de l'héparine. Leur mécanisme d'action et l'identification de leur site actif responsable de leur activité anticoagulante ont été abordés. Différentes fractions ont été éluées sur des colonnes couplées aux inhibiteurs plasmatiques principaux, l'antithrombine et le deuxième cofacteur de l'héparine. Des fractions de haute affinité ont pu être purifiées et caractérisées.
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Azevedo, Tarciana Carvalho Gurgel de. "A??o de polissacar?deos sulfatados de Fucus Vesiculosus na Hemostasia e no sistema complemento." Universidade Federal do Rio Grande do Norte, 2006. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12606.
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Fucans are a family of sulfated homo and teropolysaccharides respectively, composed mainly of a- (1?2) and a- (1?3) linked by L-fucose residues. Properties such as the ability to act as an anti-contraceptive, to reduce cholesterol levels, and to act as an anti-tumor agent are much related. We have focused our attention on the anticoagulant properties, platelet aggregation, hemorrhagic activity and complement system in vitro of commercial fucoidan (F) and their purified fractions (F1, F2 and F3) from Fucus vesiculosus obtained from fractionation of the fucoidan with different concentrations of acetone 1, 2 and 3v. These compounds were chemically characterized and the fucoidan (F) was modified by desulfation. The anticoagulant activity of the compounds was assessment by activated partial thromboplastin time (APTT) and prothrombine time assay (PT) using citrated normal human plasma. The results of APPT test showed that F, F1 and F2 have high anticoagulants activities 240.0 s (5 ?g). The F3 showed 73.7 s in the same concentrations. The results obtained with PT test to F, F1, F2 and F3 were 81.5 s, 120.0 s, 57.1 and 32.5 s respectively with 50 ?g. The dessulfated polymer showed a decrease in the anticoagulant activity in these two tests. Platelet aggregation assay was measured turbidimetrically with platelet aggregometer by method of Born. The aggregation platelet with F and fractions F1, F2 and F3 exhibited a two-phase answer in the concentration of 5 mg/mL with maximum aggregation of 76.36 ? 10.3% ; 69.54 ? 9.40%; 75.94 ? 9.01%; 51.13 ? 9.59% respectively. However, was observed a hipoaggregate profile F (15.17 ? 5.2%), F1 (7.40 ? 3.04 %), F2 (19.1 ? 5.41%) and F3 (5.09 ? 3.02%) at 0.1 mg/mL. The hemorrhagic activity assay was carried in Wistar rats and showed that these compounds have low hemorrhagic effect when compared to heparin. The complement system ( alternative pathway was made using non-sensibilized rabbit red blood cells The results of complement system essay showed that F , F2 and F3 have action inhibitory in relation to the group control 0.544, 0.697, 0.622 and 0.958 respectively The results showed that these compounds have action on this system. Interaction of the polisaccharides with proteins C3 and C4 showed that the fraction F1 stimulated the activity assay hemolytic using red blood cells
Fucanas s?o uma fam?lia de homo e hetero polissacar?deos sulfatados, formadas por uma cadeia central com liga??es α-(1→2) ou α-(1→3) unidas atrav?s de res?duos de L-fucose. Propriedades como a habilidade para agir como um anticoncepcional, reduzir n?veis de colesterol, e agir como um agente anti-tumoral foram relatadas. N?s focalizamos nossa aten??o nas propriedades anticoagulantes, agrega??o plaquet?ria, atividade anti-hemost?tica e sistema de complemento in vitro do fucoidan comercial e das fra??es F1, F2 e F3 de Fucus vesiculosus obtidas atrav?s do fracionamento do fucoidan por precipta??o com acetona (1, 2 e 3v). A atividade anticoagulante dos compostos foi avaliada pelo tempo de tromboplastina parcial ativado (APTT) e o tempo de protrombina (PT) usando plasma humano citratado. Os resultados do teste de APPT mostraram que o Fucoidan (F) e as fra??es F1 e F2 t?m altas atividades anticoagulantes 240,0 s (5 ?g), enquanto que a F3 mostrou 73,7s nas mesma concentra??o. Os resultados obtidos com PT para o F, F1, F2 e F3 foram 81,5 s, 120,0 s, 57,1 e 32,5 s respectivamente usando a massa de 50 ?g. A dessulfata??o do Fucoidan demonstrou uma diminui??o da atividade anticoagulante nos dois testes. O ensaio de agrega??o plaquet?ria foi realizado no agregometro de acordo com o m?todo de Born. A agrega??o plaquet?ria induzida pelo fucoidam e pelas fra??es de F1, F2 e F3 exibiram uma resposta bif?sica na concentra??o de 5 mg/mL com amplitude m?xima de agrega??o de 76,36% ? 10,3%; 69,54% ? 9,40%; 75,94% ? 9,01%; 51,13% ? 9,59% respectivamente. Por?m, na concentra??o 0,1 mg/mL foi observada um perfil hipoagregante para o Fucoidan (15,17% ? 5,2) e para as fra??es F1 (7,4% ? 3,04%), F2 (19,1% ? 5,41) e F3 (5,09% ? 3,02%). A atividade anti-hemost?tica foi realizada com ratos machos da linhagem Wistar e demonstrou que estes compostos t?m efeito hemorr?gico residual menor do que o da heparina. A a??o dos polissacar?deos fucosilados sulfatados na via alternativa do sistema complemento foi realizada atrav?s da utiliza??o de eritr?citos de coelhos n?o sensibilizados. Os resultados para o Sistema Complemento mostraram que o F, F2 e F3 t?m a??o neste sistema, apresentando efeito inibit?rio em rela??o ao grupo controle 0,544, 0,697, 0,622 e 0,958 respectivamente. Intera??es dos polissacar?deos com as prote?nas C3 e C4 demonstraram que a fra??o F1 estimula a atividade hemol?tica do complemento usando eritr?citos de coelho. Conclu?mos que estes a??cares t?m atividade anticoagulante e atuam como inibidores do sistema complemento sendo uma valiosa droga que pode ser empregada em doen?as relacionadas com inflama??o e coagula??o sang??nea
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McCabe, N. R. "Training and fucose metabolism in chick brain." Thesis, Open University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355645.
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Ellouali, Mostafa. "Les fucanes, polysaccharides sulfatés extraits d'algues brunes : activités antiproliférative et antitumorale et mécanisme d'action." Paris 13, 1994. http://www.theses.fr/1994PA132001.
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Les fucanes sont des polysaccharides sulfatés extraits des algues brunes marines. Ces polysaccharides possèdent de nombreuses propriétés biologiques intéressantes en pharmacologie et en médecine (activité anticoagulante, antiinflammatoire, anticonceptionnelle, antivirale. . . ). De nombreux travaux récents ont étudié notamment leur activité antitumorale in vitro et in vivo. Nous nous sommes donc intéressés aux activités antiproliferative et antitumorale in vitro de ces composés. En raison de leur hétérogénéité et de leur haute masse molaire, ils sont dégradés par une hydrolyse acide puis fractionnés par chromatographie sur gel de filtration. Chaque fraction est caractérisée de part sa masse molaire et ses taux de soufre, d'azote, d'unités l-fucose et d'acide uronique. Les fractions ainsi obtenues et l'extrait brut sont ensuite étudiés in vitro sur 5 lignées cellulaires; les ccl 39, les colo 320dm, les mccoy, les mcf7 et les p388. Au cours de cette 2tude, nous avons montré que seule la croissance des ccl 39 et des colo 320dm est inhibée par ces composés. L'action de ces polysaccharides est donc spécifique. Les pourcentages d'inhibition varient selon les cellules et atteignent 80% dans le cas des ccl 39 et 40% dans le cas des colo 320dm à la concentration en fucanes de 500 g/ml. La concentration active de ces fractions de fucanes varie de 1 a 10 g/ml. Toutes les fractions sont aussi actives que l'extrait brut et ne sont pas cytotoxiques pour les cellules. Cette activité des fucanes est réversible et dépendante de la densité cellulaire et de la concentration en svf dans le milieu de culture. Ces fractions de fucanes ont montré aussi une activité antiadhesive sur les mccoy. Cette action est spécifique de ces cellules. Les études de fluorescence ont montré que l'effet antiproliferatif des fucanes n'est dû ni à leur internalisation ni à une action au niveau de l'acide desoxyribonucleique (adn). Par contre, il semblerait qu'ils exercent leur action sur les cellules en perturbant le métabolisme des protéines d'adhésion telle que la thrombospondine. Il semblerait aussi que les groupes sulfates ainsi qu'une masse molaire de 10000 g/mol, correspondant à une cinquantaine d'unités osidiques, sont indispensables pour l'activité antiproliferative de ces polymères. Cette action antiproliferative des fucanes n'est médieée ni par les fgfs ni par l'héparine h108. Les études de radiomarquage ont montré que les fucanes, comme l'héparine h108, ne sont pas dégradés dans les ccl 39 après leur internalisation. L'héparine h108 se déplace de la même manière et avec la même efficacité que le fucane froid, le fucane radiomarque fixé sur les ccl 39. Ceci signifie que ces deux polysaccharides agissent via les mêmes recepteurs. L'interaction de ces deux polysaccharides avec les membranes des ccl 39 est un phénomène saturable montrant un maximum de 10exp8 molécules fixées par cellule avec une affinité apparente de l'ordre de 10 8 m1. Le mécanisme d'action des fucanes n'est pas encore élucidé. En raison de leur diversité structurale, d'autres études sont indispensables sur d'autres lignées cellulaires afin de comprendre les relations existantes entre leur structure, la nature des interactions et les activités biologiques qui en resultent
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Lima, Jailma Almeida de. "An?lise toxicol?gica in vitro e in vivo de uma fucana antitromb?tica da alga marrom Spatoglossum schd?ederi." Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12548.
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Fucan is a term used to denominate a family of sulfated polysaccharides rich in L-fucose. They are extracted mainly from the extracellular matrix of brown algae and echinoderms. The brown alga Spatoglossum schr?ederi (Dictyotaceae) has three heterofucans named A, B and C. Our research group have been extracted non anticoagulant heterofucan from S. schr?ederi which possess antithrombotic activity in vivo. However, their toxicity in vitro and in vivo has not yet been determined. For the results in toxicity in vitro, we observed that the fucan A at 20, 500 and 1000 μg/plate showed no mutagenic activity in Kado test (Microsuspension), when the bacterial strains TA97a, TA98, TA100 and TA102, with and without S9 were used. The comet assay showed that fucan A (from 20 to 1000 μg/mL) did not cause any genotoxic effect on CHO cells. There was no damage to the DNA of these cells, as evidenced by the tail length and tail moment, which were similar to that found for the negative control. The fucan A from S. schr?ederi was administered at 20 μg/g of rat (dose which it showed high antithrombotic activity) during two months. After that, the animals were killed and examined. The data showed that fucan A did not cause any change in biochemistry and hematological parameters, as well as, in the morphology and size of the rat s organs analyzed. In conclusion, this study indicates that fucan is a compound with potential pharmacological that has no toxicity
Fucana ? um termo usado para denominar uma fam?lia de polissacar?deos sulfatados ricos em L-fucose. S?o extra?dos principalmente da matriz extracelular de algas marrons e equinodermas. A alga marrom Spatoglossum schr?ederi (Dictyotaceae) possui tr?s heterofucanas nomeadas de fucanas A, B e C. Tem sido proposto o uso de fucanas como alternativas para anticoagulantes. Nosso grupo de pesquisa extraiu uma heterofucana n?o anticoagulante da alga S. schr?ederi que tem uma elevada atividade antitromb?tica in vivo. No entanto, a sua toxicidade in vitro e in vivo ainda n?o foi determinada. Para os resultados obtidos na toxicidade in vitro, observou-se que a fucana A nas concentra??es de 20, 500 e 1000 μg/placa n?o mostram atividade mutag?nica em teste Kado (Microsuspens?o) utilizando a cepas bacterianas TA97a, TA98, TA100 e TA102, com e sem S9. No ensaio do cometa a presen?a da fucana A n?o provocou nenhum efeito genot?xico nas concentra??es testadas de 20, 500 e 1000 μg/mL. N?o houve dano no DNA dessas c?lulas, como evidenciado pelo tail lenght e tail moment, sendo semelhantes ao encontrado para o controle negativo. A fucana A da alga Spatoglossum schr?ederi quando administrada nos animais durante o per?odo de dois meses, n?o provocou altera??o dos par?metros hematol?gicos, bioqu?micos, morfologia e tamanho dos ?rg?os analisados. Esse teste n?o demonstrou que a fucana, na dose que apresenta atividade antitromb?tica, apresenta toxicidade. Os dados do trabalho indicam que esta fucana ? um composto com potencial farmacol?gico que n?o apresenta toxidade, esse fato da seguran?a para que testes futuros com esse pol?mero sejam realizados, inclusive testes em humanos
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Yuan, Kun. "Effects of defucosylation on human breast cancer cells." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2010r/yuan.pdf.
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Fraser, Ceridwen, and n/a. "Phylogeography of the kelp genus Durvillaea (Phaeophyceae: Fucales)." University of Otago. Department of Zoology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20091002.131226.
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Durvillaea, a kelp genus occurring only in the Southern Hemisphere, presents an ideal system for studies of marine connectivity and postglacial recolonisation. Durvillaea contains five currently-recognised species, four of which are non-buoyant. Whereas all non-buoyant species are restricted to the south-western Pacific, the sole buoyant species (D. antarctica) has a far wider, circumpolar distribution, strongly suggesting that long-distance dispersal in D. antarctica is achieved by rafting. This contrast in predicted dispersal ability among Durvillaea species provides an opportunity for natural phylogeographic comparisons, thereby assessing the effectiveness of rafting as a long-distance dispersal mechanism. Additionally, the inability of D. antarctica to survive in ice-affected areas, combined with its broad distribution, make it an ideal candidate for studies of postglacial recolonisation.
Phylogenetic and biogeographic relationships within Durvillaea were here assessed using sequence data from mitochondrial (COI), chloroplast (rbcL) and nuclear (18S) DNA. Genetic data were obtained from more than 500 specimens, including representatives from across the geographic range of each recognised species of Durvillaea. Mitochondrial data for Durvillaea were found to be highly phylogenetically informative, with 117 variable sites observed over a 629 bp fragment of COI. Chloroplast and nuclear markers, on the other hand, showed less variation than COI, but nonetheless contributed useful phylogenetic information. Phylogenetic analyses were performed using both Maximum Likelihood and Bayesian approaches.
Contrasting patterns of genetic diversity were observed across the range of D. potatorum in Australia, with genetic homogeneity throughout western sites versus relatively high levels of diversity in eastern populations. Based on these results, I hypothesise that D. potatorum recolonised much of the western part of its range postglacially, perhaps being entirely eliminated from western Tasmania during the last glacial period by altered oceanographic systems. Additionally, 'western' and 'eastern' D. potatorum haplotypes formed deeply-divergent clades, likely reflecting geographic isolation on either side of the Bassian Isthmus during Pleistocene marine regressions.
Substantial genetic diversity was observed across the range of the circumpolar species D. antarctica. Within New Zealand, phylogenetic and morphological analyses of D. antarctica indicate that two morphotypes ('cape' and 'thonged' forms) likely represent reproductively isolated species, with the 'cape' lineage apparently restricted to southern New Zealand. Whereas the 'cape' lineage showed little genetic variation throughout its range, the 'thonged' lineage exhibited marked phylogeographic structure, with high genetic diversity and a clear north - south genetic disjunction delineated by the Canterbury Bight.
On a broader, circumpolar scale, D. antarctica showed contrasting patterns of genetic diversity, with high levels of variation in low-latitude regions (e.g., continental coasts of New Zealand and Chile), versus near-homogeneity at high, subantarctic latitudes. These phylogeographic contrasts strongly suggest that D. antarctica recolonised much of the subantarctic region only recently, most plausibly following extirpation by ice scour at the Last Glacial Maximum (LGM). Locations of putative recolonised islands relative to 'refugial' areas indicate that Antarctic sea ice was likely more extensive at the LGM than previous studies have suggested.
Latitudinal contrasts in genetic diversity were also observed among Chilean populations of D. antarctica, with a single mitochondrial haplotype detected throughout Chilean Patagonia versus high diversity in central Chile (32�-42�S). The Patagonian populations appear to have recolonised the region postglacially, following recession of the Patagonian Ice Sheet after the LGM. These populations show transoceanic ancestry, with a closer relationship to populations in the subantarctic and southern New Zealand regions than to those in central Chile. Substantial phylogeographic structure was evident across small spatial scales in central Chile, and the correspondence of major genetic disjunctions among central Chilean sites with the presence of long stretches of unsuitable substrate (beaches) strongly suggests that habitat discontinuity drives genetic isolation in this dispersive species.
Broad-scale molecular phylogenetic analyses indicate that the current taxonomy of Durvillaea species requires substantial revision. Previously-recognised 'morphotypes' of Durvillaea (of D. potatorum in Australia, and D. antarctica in New Zealand), for example, were here found to be genetically distinct, likely representing reproductively-isolated species.
This phylogeographic research on Durvillaea kelp sheds new light on the historical impacts of climate change on Southern Hemisphere marine environments, and on the processes driving evolution in a marine macroalga.
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Rosa, Eliana Migliorin da. "Responsabilidade social na FUCAPI: visão atual e perspectivas." Universidade Federal de Minas Gerais, 2004. http://hdl.handle.net/1843/BUBD-9A3FM4.
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The depth of involvement of an organization with the issue of social responsibility can be studied by using a hierarchical model (MONTANA & CHARNOV, 1998). At its most primitive stage, an organization only fulfills its legal obligations whereas, if it is at the most advanced stage, it also adopts a proactive attitude, where it commits itself to solving social
problems, even though only indirectly affected by them. The Centre for Analysis, Research and Technological Innovation Foundation (FUCAPI) is the subject of this case study. In order to investigate what type of approach FUCAPI has taken towards social issues in its social
activities, its managers and employees were interviewed and their responses were compared with institutional documents. FUCAPIs approach to social responsability was analysed by using Montana & Charnovs (1998) theoretical model and recommendations were made so that the organization could become more effective and proactive in its social actions.O nível de envolvimento e amadurecimento de uma organização com o tema responsabilidade social pode ser estudado com base num modelo hierárquico (MONTANA & CHARNOV, 1998). Num estágio mais primitivo, a organização limita-se a satisfazer suas obrigações legais, ao passo que, se estiver no estágio mais avançado, adota também uma postura proativa, comprometendo-se com a solução de problemas sociais, mesmo que só indiretamente a afetem. A Fundação Centro de Análise, Pesquisa e Inovação Tecnológica (FUCAPI) é o objeto deste estudo de caso. Para investigar que tipo de orientação às questões sociais a FUCAPI tem demonstrado por intermédio de suas ações sociais, foram entrevistados gerentes e trabalhadores da organização, e seus depoimentos foram cotejados com documentos institucionais. Com referência ao modelo teórico de Montana & Charnov (1998), abordagem de responsabilidade social da FUCAPI foi, analisada e foram feitas recomendações para que a organização torne-se mais eficaz e proativa em suas ações sociais.
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Costa, Thiago Gomes. "Caracteriza??o estrutural e avalia??o das atividades farmacol?gicas da fucana B extra?da da alga Dictyota menstrualis." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12628.
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Previous issue date: 2014-02-06Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
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
Algas marinhas s?o uma das principais fontes de compostos biologicamente ativos. Na matriz extracelular desses organismos existem os polissacar?deos sulfatados que funcionam como componente estrutural prevenindo-a contra desidrata??o. A fra??o 0,9 (FucB) rica em fucanas sulfatadas obtida da alga marrom Dictyota menstrualis foi caracterizada quimicamente e avaliada quanto a atividade farmacol?gica por meio de ensaios de atividade anticoagulante, a??o estimulat?ria sobre a s?ntese de heparam sulfato antitromb?tico, atividade antioxidante e seus efeitos na prolifera??o celular. Os principais componentes da FucB foram carboidratos (49,80 ? 0,10%) e sulfato (42,30 ? 0,015%), apresentando compostos fen?licos (3,86 ? 0,016%) e baixa contamina??o prot?ica (0,58 ? 0,001%). FucB mostrou perfil polidisperso e sinais na an?lise de infravermelho em 1262, 1074 e 930 e 840 cm-1 atribu?dos a liga??es S=O de ?steres de sulfato, presen?a de liga??o C-O de 3,6-anidrogalactose, β-D-galactose n?o sulfatada e sulfato na posi??o axial do C4 da fucose, respectivamente. FucB exibiu moderada atividade anticoagulante, este polissacar?deo prolongou o tempo de tromboplastina parcial activada (aPTT) a 200 ug (>90s) n?o foi observado qualquer efeito de FucB sobre o tempo de protrombina (PT), que corresponde a via extr?nseca da coagula??o. Esta fra??o promoveu estimula??o cerca de 3,6 vezes na s?ntese de heparam sulfato (HS) pelas c?lulas endoteliais da aorta de coelho (RAEC), em cultura, quando comparadas com as c?lulas n?o tratadas com FucB. Esta tamb?m demonstrou competir pelo s?tio de liga??o com a heparina. A fra??o rica em fucanas sulfatadas exibiu forte a??o antioxidante sobre os ensaios de antioxidante total (109,7 e 89,5% comparados com padr?es BHT e ?cido asc?rbico), poder redutor (71% comparado ao ?cido asc?rbico) e quela??o f?rrica (71,5% comparando com ?cido asc?rbico). A fra??o dessa alga mostrou atividade citost?tica sobre as c?lulas RAEC revelando que o aumento da s?ntese de heparan sulfato n?o est? relacionado ? prolifera??o. FucB apresentou a??o antiproliferativa sobre linhagens celulares modificadas como Hela e Hep G2 pelo ensaio de MTT. Esses resultados sugerem que FucB de Dictyota menstrualis tem potencial anticoagulante, antitromb?tico, antioxidante bem como uma poss?vel a??o antitumoral, promovendo a estimula??o da s?ntese de HS antitromb?tico pelas c?lulas endoteliais, sendo ?til na preven??o da trombose, devido tamb?m a sua a??o inibit?ria sobre as esp?cies reativas do oxig?nio (ROS) em alguns sistemas in vitro, estando envolvidos na promo??o de estado de hipercoagulabilidade
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Barroso, Edjane Maria de Azevedo. "Efeito antitromb?tico de uma fucana n?o anticoagulante extra?da da alga Spatoglossum Schr?ederi." Universidade Federal do Rio Grande do Norte, 2008. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13201.
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Previous issue date: 2008-07-30Fucan is a term used to denominate a family of sulfated L-fucose-rich polysaccharides. The brown alga Spatoglossum schr?ederi (Dictyotaceae) has three heterofucans namely fucan A, B and C. The 21 kDa fucan A is composed of a core of β (1-3) glucuronic acid-containing oligosaccharide of 4.5 kDa with branches at C4 of fucose chains α (1-3) linked. The fucose is mostly substituted at C4 with a sulfate group and at C2 with chains of β (1-4) xylose. This fucan has neither anticoagulant (from from 0.1 to 100?g) nor hemorrhagic activities (from 50 to 800 ?g/mL). The antithrombotic test in vivo showed the fucan A has no activity in any of the concentrations (from 0.2 to 20?g/g/day) tested 1h after polysaccharide administration. However, when fucan A was injected endovenously 24h before the ligature of the venae cavae, we observed a dose-dependent effect, reaching saturation at around 20g/g of rat weight. In addition, this effect is also time-dependent, reaching saturation around 16h after fucan administration. In addition, regardless of administration pathway, fucan A displayed antithrombotic action. The exception was the oral pathway. Of particular importance was the finding that fucan A stimulates the synthesis of an antithrombotic heparan sulfate from endothelial cells like heparin. The hypothesis has been raised that in vivo antithrombotic activity of fucan A is related to the increased production this heparan. Taken together with the fact that the compound is practically devoid of anticoagulant and hemorrhagic activity suggests that it may be an ideal antithrombotic agent in vivo
Fucanas ? um termo utilizado para denominar a fam?lia de polissacar?deos sulfatados que apresentam em sua constitui??o α-L-fucose sulfatada. A alga marrom Spatoglossum schr?ederi da fam?lia Dictyotaceae, apresenta tr?s heterofucanas denominadas de fucana A, B, e C. A fucana A (21kDa) ? composta por um n?cleo central formado por ?cido glucur?nico, β 1→3 ligado, substitu?dos em C4 por L-fucoses α (1→3) ligados. A fucose ainda ? substitu?da no C4 por grupos sulfatos e no C2 por cadeias de β (1→4) xilose. Esta fucana n?o apresentou atividade anticoagulante entre 0,1 e 100?g/mL e nenhuma atividade hemorr?gica entre 50 e 800?g /mL. Os testes antitromb?tico in vivo mostraram que a fucana A n?o apresentou atividade nas concentra??es (0,2 a 20?g/g) testadas 1 hora ap?s a administra??o do polissacar?deo. No entanto, quando a fucana A foi administrada endovenosamente, 24h antes da ligadura da veia cava, observou-se um efeito dose-dependente, alcan?ando a sua satura??o em torno de 20?g/g de massa do animal. Al?m disso, o efeito se mostrou tempo-dependente, atingindo satura??o em 16h ap?s a administra??o da fucana. Em todas as vias em que foi administratada (SC, IM, IP, e IV), a fucana A demonstrou a??o antitromb?tica. Exce??o apenas para a via oral. A import?ncia dos resultados obtidos foi o fato da fucana A estimular a s?ntese de um heparam sulfato com caracter?sticas antitromb?tica semelhante ? heparina pelas c?lulas endoteliais. Esta descoberta levou a hip?tese de que a atividade antitromb?tica da fucana A est? relacionada com o aumento na produ??o deste heparam sulfato. Devido as suas caracter?sticas e por ser um composto praticamente desprovido de atividade anticoagulante e hemorr?gico sugere-se que a fucana A possa vir a ser um agente antitromb?tico in vivo . A realiza??o deste estudo teve car?ter multidisciplinar, envolvendo pesquisadores da Bioqu?mica, Morfologia, Hematologia, Bot?nica e Veterin?ria. Este aspecto preencheu os requisitos da multidisciplinaridade do Programa de P?s-Gradua??o em Ci?ncias da Sa?de
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ANDRADE, Priscyla Lima de. "Síntese e caracterização da magnetita revestida por polímeros naturais (fucana e levana) para imobilização de enzimas." Universidade Federal de Pernambuco, 2009. https://repositorio.ufpe.br/handle/123456789/1703.
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Previous issue date: 2009Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Atualmente com o advento da nanociência e nanotecnologia, as nanoparticulas magnéticas têm encontrado inúmeras aplicações nos campos da biomedicina, diagnóstico, biologia molecular, bioquímica, catálise, etc. As nanoparticulas magnéticas funcionalizadas são constituídas de um núcleo magnético, envolvidos por uma camada polimérica com sítios ativos, que podem ancorar metais ou compostos orgânicos seletivos. Estas nanopartículas são consideradas materiais híbridos orgânico-inorgânicos de grande interesse em aplicações comerciais, são elas: carregadores de fármacos, tratamento de magnetohipertermia, seleção de moléculas específicas, biossensores e etc. Este trabalho foi desenvolvido em duas partes: a primeira foi obter a magnetita através do processo da co-precipitação de uma solução que contém íons de Fe (II) e de Fe (III) no meio aquoso alcalino. A segunda parte foi à escolha dos polissacarídeos Levana e Fucana que foram utilizados para cobrir o núcleo magnético. As partículas estudadas foram caracterizadas através da microscopia eletrônica de varredura (MEV), medidas da magnetização, difratômetro de raios - X (DRX) e absorção no infravermelho (IV). Elas se mostram maiores quando comparadas à magnetita de acordo com as imagens obtidas no MEV. O DRX mostrou que a magnetita é a fase dominante nas partículas revestidas pelos polímeros. O espectro de IV mostrou faixas de absorção características do polissacarídeo levana, fucana e da magnetita as ligações presentes foram O-H, C-O-C e Fe-O. Os resultados da magnetização mostram que a magnetita revestida com fucana tem uma maior saturação e é muito mais fácil de magnetizar do que a magnetita revestida com levana
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Sanz, Sender Silvia. "Synthesis and biological function of fucose in Plasmodium falciparum." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/587108.
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Malaria is a parasitic disease caused by Plasmodium parasites and it is transmitted by female Anopheles mosquito. P. falciparum has a complex life cycle that includes important stages in two different hosts: a mosquito and a human. The transmission between the human and the mosquito host also involves the transition between asexual and sexual forms of the parasites.
Glycobiology includes the study of carbohydrate metabolism and glycoconjugate (glycoprotein and glycolipid) structures. Protozoan parasites synthesize different glycoconjugates for protection and to respond to changes in the environment. Glycoconjugates coat the parasite surface with carbohydrates generally different from the host ones. They are crucial for parasite virulence and survival. Until very recently the only glycan structures described in P. falciparum were the GPI-anchors, however other glycan structures have been found in the past few years as the N-glycans or C-mannosylation. The glycome consists in the complete set of glycosylations that an organism or a cell produces at a certain time point, therefore the description of the parasite glycome may help to understand better the host- pathogen interactions in parasitic diseases. Sugar nucleotides are activated forms of monosaccharides that are the donors of glycosyltransferases to form glyconjugates. They can be synthesized by a de novo pathway that consists in the bioconversion of an existing sugar or sugar nucleotide; or by a salvage pathway that involves an activation and a further pyrophosphorylation. The identification and quantification of the sugar nucleotides present in malaria parasites may help to describe its glycosylation profile.
The first paper presented in the thesis describes the identification and quantification of the sugar nucleotides present in the parasite, among which we found: UDP-Glc, UDP-Gal, UDP-GlcNAc, GDP-Man and GDP-Fuc. We also investigated the salvage pathways present in the parasite but we couldn’t elucidate the presence of a fucose salvage pathway. Plasmodium parasites conserve homolog genes for the de novo biosynthetic pathway of GDP-Fuc: GMD and FS. We were able to prove the in vitro activity of GMD and FS enzymes and to show that both enzymes are required for the synthesis of fucose. GMD and FS are expressed along the intraerythrocytic life cycle and both enzymes localize in the cytoplasm of the parasite, as well as other parasite enzymes related with carbohydrate metabolism. The expression of a putative O-fucosyltransferase (PoFUT2) present in the parasite genome, together with the uptake of GDP-Fuc by parasite extracts suggested the presence of a fucose containing glycan.
In the second paper, we characterized the enzymes responsible for the synthesis of GDP-Fuc, GMD and FS. We disrupted both genes in the parasite and analyzed the sugar nucleotide content present in the parasite. After GMD and FS disruption, GDP-Fuc was still detected in the parasite and no evidence of salvage mechanism was found. We described indirect evidence of a fucose containing glycan that was abrogated after the disruption of GMD.
The last work here presented (not yet published) tries to characterize the enzyme that is probably responsible for the transfer of fucose to the glycoconjugate. We disrupted, by double crossover recombination, PoFUT2 gene in the human and in the rodent malaria parasite. The disruption of PoFUT2 does not have any significant effect for the viability and growth of the parasite along the parasite cycle in the human and in the mosquito host.
These works open the door to new research lines to find an alternative pathway for obtaining fucose or GDP-Fuc. Obtaining evidence of the glycosylation state of PoFUT2 mutants and the characterization of other possible glycosylation reaction present in the parasite are other research topics to investigate.La malaria está causada por el parásito Plasmodium y se transmite mediante hembras del mosquito Anopheles. La glicobiología es el estudio de los procesos relacionados con los carbohidratos y las estructuras glicoconjugadas que forman. Los parásitos sintetizan glicoconjugados o proteínas de unión a glicanos, y muchas veces se encargan de mediar las interacciones huésped-patógeno. Los azúcares nucleótidos son formas activadas de monosacáridos que son usados por glicosiltransferasas para formar glicoconjugados. La identificación y cuantificación de estos azúcares nucleótidos en el parásito de la malaria puede contribuir a la definición de su perfil de glicosilación. El primer trabajo presentado en la tesis permitió identificar los azúcares nucleótidos presentes en el parásito, así como la posible presencia de un glicoconjugado que contenga fucosa, sintetizado a partir de la actividad O-fucosiltransferasa de una proteína homóloga anotada en el genoma del parásito, PoFUT2. El siguiente trabajo permitió caracterizar las enzimas implicadas en la síntesis de la GDP-fucosa, GMD y FS. Este artículo nos permitió mostrar evidencias indirectas de la presencia del glicococonjugado que contiene fucosa. A partir de la disrupción de los genes de biosíntesis descubrimos que el contenido de GDP-fucosa en parásitos mutantes no variaba con respecto a los parásitos salvajes. Sin embargo, la síntesis del gliconjugado sí que se reducía. El tercer trabajo (sin publicar) se centra en la caracterización de la enzima encargada de transferir la fucosa al glicoconjugado. La disrupción de PoFUT2 no parece tener ningún efecto en la viabilidad y crecimiento del parásito a lo largo del ciclo de éste en el humano y en el mosquito. Estos trabajos abren la puerta a nuevas investigaciones para descubrir una vía alternativa de obtención de GDP-Fucosa. La obtención de evidencias del estado de glicosilación de los mutantes de PoFUT2 y la caracterización de otras posibles glicosilaciones son otros temas a investigar.
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Dunmore, Robyn Ann. "Demography of early life stages of habitat-forming intertidal fucoid algae." Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1364.
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The intertidal zone is finely partitioned in species distributions and abundances. The demographies of key species over varying spatial and temporal scales are fundamental to understanding the population structure and overall dynamics of habitats and assemblages. In this thesis, settlement, dispersal and early life stage survival and growth were examined in several habitat-forming intertidal fucoid algae in New Zealand and Oregon, U.S.A. Natural settlement patterns of Hormosira banksii, Cystophora torulosa and Cystophora scalaris were quantified for over three years at a semi-protected shore in southern New Zealand. Settlement was monitored in four tidal zones, within bare rock and algal habitats. Settlement was synchronous between tidal zones but the density of settlement varied spatially and temporally. There were significant differences between tidal zones, habitats and times of the year. For H. banksii, small pulses of settlement occurred year-round with greatest densities during spring and early summer. Greatest settlement occurred at low tidal zones and under adult canopies. Both Cystophora species also reproduced year-round, but had much lower settlement densities than H. banksii. Most settlement occurred during spring and summer, while only small pulses occurred in autumn and winter months. Most settlement was in the lowest tidal zone (0.4 m above chart datum), with only a few zygotes settling at higher shore zones. Canopy cover had no significant effect on settlement densities. Dispersal was examined in Durvillaea spp., H. banksii, C. torulosa and Fucus gardneri. For all species, settlement densities declined with distance from the source populations, but densities were variable between species. Durvillaea spp. dispersal was more extensive than expected, with significant settlement occurring 32 m from the source population, the maximum sample range of the study. However, settlement densities were much higher within 8 m from the source. The extensive dispersal of Durvillaea spp. is a result of the combination of small, slowly sinking eggs and the presence of buoyant mucilage. The other species studied showed far more restrictive dispersal, and much lower settlement densities. Settlement occurred 2 m from the source, but most settlement occurred under or near the canopy. The eggs of these species are much larger and sink faster than the eggs of Durvillaea spp. The consequences of settling at different shore heights and seasons were examined in H. banksii and D. antarctica in New Zealand, and F. gardneri and Pelvetiopsis limitata in Oregon. Transplant experiments tested the effects of grazing and heat/desiccation stress on survival and growth of germlings at different shore heights, during different seasons. High germling mortality was a feature of all species, but rate of mortality depended on conditions and species. There is a trade-off for settling at different times of the year; overall, growth was faster in warmer seasons, but survival was better in cooler seasons. During cooler seasons, germlings are exposed to less heat/desiccation stress, but their slow growth exposes them to grazing and competitive interactions for longer periods. For New Zealand species, shore height had large effects, with better survival and growth in the low shore. Grazers were very effective in the low shore, and heat/desiccation stress had strong effects in the mid and high shores. For Oregon species, effects of grazing and heat/desiccation stress were generally weaker than for New Zealand species. Shore height had weak effects, but ultimately low shore germlings had poor survival, primarily because of overgrowth by ephemeral algae. This is in contrast to the generalisation that survival and growth in the low shore should be better due to a more benign environment. In this study, species had specific demographies that related to their life history characteristics and responses to the local environment. Differences in settlement, dispersal abilities, survival and growth over small spatial and temporal scales clearly underpinned large scale differences in recruitment and adult distribution and abundances.
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GIRAUX, JEAN-LUC. "Interaction entre les fucanes, polysaccharides sulfates, polysaccharides sulfates anticoagulants et antithrombotiques, et les cellules endothéliales vasculaires humaines." Paris 13, 1998. http://www.theses.fr/1998PA132021.
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Les fucanes sont des polysaccharides sulfates anticoagulants et antithrombotiques extraits d'algues brunes. Nous avons etudie l'interaction in vitro de deux fractions de fucane (q2 et e bp1-4), isolees par des techniques de purification differentes et de masses moleculaires differentes, avec les cellules endotheliales de la veine de cordon ombilical humain. Nous avons montre que le fucane (comme l'heparine) stimule la secretion du tfpi par les cellules endotheliales de maniere temps- et dose-dependante. L'activite antithrombotique du fucane pourrait donc impliquer, en plus de la catalyse d'inhibition de la thrombine par le deuxieme cofacteur de l'heparine (et l'antithrombine), la liberation de tfpi par les cellules endotheliales vasculaires. Nous avons observe une potentialisation de la proliferation des cellules endotheliales par les deux fractions de fucane en presence de serum. Cet effet est dose-dependant, avec un effet significatif a 1 g/ml (augmentation d'environ 30% de la densite cellulaire par rapport au temoin). Dans les memes conditions, l'heparine a montre un effet inhibiteur pour des concentrations superieures a 1 g/ml. En presence de fgf-1, les deux fractions de fucane potentialisent la proliferation cellulaire, mais a des doses 10 fois plus fortes que pour l'heparine. En presence de fgf-2, le fucane (comme l'heparine) inhibe la proliferation des cellules endotheliales. Par ailleurs, nous avons mis en evidence, en l'absence de fgf, une faible inhibition de la reparation vasculaire (modele de desendothelialisation partielle de la monocouche a l'aide d'une lame de rasoir) observee seulement en presence de fortes concentrations de polysaccharides sulfates (100 g/ml). En presence de fgf-1, le fucane (comme l'heparine) potentialise la reparation vasculaire. Cet effet est plus marque en presence du fucane q2 que du fucane e bp1-4. De fortes concentrations de ces polysaccharides sulfates (100 g/ml) induisent une faible inhibition de la reparation vasculaire en presence de fgf-2. En presence de vegf, il n'y a pas de potentialisation par le fucane (comme par l'heparine) de la proliferation et de la reparation vasculaire. Le fucane module donc la proliferation des cellules endotheliales et la reparation vasculaire, propriete interessante dans une eventuelle utilisation en thrombose arterielle.
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Muiry, Jennifer Anne Ross. "The bacterial transport systems for L-rhamnose and L-fucose." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315190.
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Fuckner, Márcio. "Combinação de classificadores usando IAD / Márcio Fuckner ; orientador, Fabrício Enembreck." reponame:Biblioteca Digital de Teses e Dissertações da PUC_PR, 2008. http://www.biblioteca.pucpr.br/tede/tde_busca/arquivo.php?codArquivo=2500.
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Dissertação (mestrado) - Pontifícia Universidade Católica do Paraná, Curitiba, 2008Bibliografia: p. 73-79
A execução de algoritmos de aprendizagem de máquina para identificaçãoo de padrões ou realização de predição é uma etapa importante da mineração de dados. A fusão das técnicas de mineração de dados e computação distribuída viabiliza a execução de algoritm
The execution of machine learning algorithms in order to identify trends or prediction purposes is an important step in the data mining context. The fusion of data mining techniques and distributed computing leverages the execution of machine learning alg
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Yao, David C. "Roles of O-fucose Molecules in Notch Signaling and Hematopoiesis." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1311379342.
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Weidner, Stefan. "Enzymatische Synthese von GDP-[beta]-L-Fucose [GDP-beta-L-Fucose] ausgehend von D-Mannose Klonierung, Expression und Charakterisierung von Enzymen aus nicht-pathogenen Enterobacteriaceae /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=972659331.
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Bandini, Giulia. "Studies on fucosylation in Trypanosoma brucei." Thesis, University of Dundee, 2011. https://discovery.dundee.ac.uk/en/studentTheses/c74554c1-f4d3-4bb3-aa31-899fcf507e11.
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The biosynthesis of GDP-Fucose, the activated donor for fucose, has been recently shown to be essential in the parasite Trypanosoma brucei. Fucose is a common sugar modification on eukaryotic glycan structures, but it has not been well described in trypanosomatids. To elucidate the role of fucose in T. brucei we searched for putative fucosyltransferases in this parasite. A single putative T. brucei fucosyltransferase (TbFT) was identified and recombinantly expressed in Escherichia coli. The protein was active and structural characterization of its reaction product identified it as a GDP-Fuc: ß-D-galactose a-1,2-fucosyltransferase with preference for Galß1,3GlcNAc containing structures as glycan acceptors. A procyclic form conditional null mutant for TbFT was generated and this glycosyltransferase shown to be essential for parasite growth in vitro, with the mutant cells displaying a slightly abnormal morphology and an apparent reduction in the surface high molecular weight glycoconjugate complex. Here we also describe the various experimental approaches that were used to try to identify the fucosylated glycocojugates in T. brucei. Lastly, to better understand the biosynthesis of GDP-Mannose, the starting metabolite for the biosynthesis of GDP-Fuc, we biochemically characterized T. brucei phosphomannomutase (TbPMM). Here we show this enzyme could interconvert not only mannose-phosphates, but also glucose-phosphates.
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Liu, Jian-Miao. "Effets des fucanes, polysaccharides sulfatés extraits d'algues brunes, sur l'adhérence in vitro de cellules d'adénocarcinomes mammaires : mécanismes d'action." Paris 13, 2002. http://www.theses.fr/2002PA132002.
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L'objectif de cette étude était d'approfondir le mécanisme d'action des fucanes, polysaccharides sulfatés, sur l'inhibition de l'adhérence de cellules issues de lignées d'adénocarcinomes mammaires, MCF7 et MDA-MB 231. L'adhérence cellulaire joue un rôle important durant tout le processus métastatique. Les fucanes sont des polyfucoses sulfatés extraits des algues brunes marines. Leur structure proche de celle de l'héparine leur confére des activités biologiques intéressantes en pharmacologie. De nombreux travaux ont mis en évidence leurs activités antitumorales et antimétasytatiques. Ils inhibent l'adhérence des cellules MCF7 et MDA-MB 231, sur différents substrats, protéines d'adhérence ou membrane extracellulaire reconstituée. Les fonctions sulfates jouent un rôle très important dans cette activité inhibitrice. Mais il semble que la présence de ces fonctions sur la chaîne macromoléculaire ne soit pas une condition suffisante pour obtenir un effet inhibiteur maximal. La masse molaire est aussi un paramètre déterminant dans cette activité ainsi que la nature des unités osidiques. L'effet inhibiteur est maximal pour des composés riches en unités galactoses sulfatées de fortes masses molaires. L'ensemble des résultats montre que cette propriété est en majeure partie la conséquence d'interactions que le fucane développe avec les protéines d'adhérence et en particulier la fibronectine. La liaison du fucane avec cette protéine sur des sites liant l'héparine ou d'autres sites, gênerait la reconnaissance de celle-ci par ses récepteurs (intégrines) présente à la surface des cellules. Les séquences de la fibronectine qui interagissent avec le fucane contiennent les sites liant l'héparine et aussi trois autres séquences de fortes masses molaires (70-116 kDa). D'autre part, les intégrines forment des contacts focaux et se lient avec les filaments d'actine du cytosquelette par l'intermédiaire de plusieurs protèines. L'interaction du fucane avec la membrane cellulaire empêcherait les cellules de former et de stabiliser ces points d'adhérence cellule-matrice extracellulaire essentiels à leur adhérence et leur migration. Nous avons regardé l'effet des fucanes sur l'expression des sous unités α5 et β1, qui forment, associés un des récepteurs de la fibronectine. Ils induisent une réorganisation des sous unités α5 à la surface des cellules tumorales ce qui conduit probablement à une désorganisation de l'intégrine α5β1. Quand il est testé dans des conditions physiologiques dans un modèle de chambre de perfusion à flux laminaire, le fucane induit une agrégation plaquettaire et stimile l'adhérence des cellules tumorales à l'endothélium. Ceci est contraire à l'effet recherché et ne peut être exploité dans le cadre d'un agent antimétastatique.
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Hawes, Nicola Ann. "Nearshore Dispersal and Reproductive Viability of Intertidal Fucoid Algae : how effective is drift in local to regional dispersal?" Thesis, University of Canterbury. School of Biological Sciences, 2008. http://hdl.handle.net/10092/2103.
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The ecological importance of drifting will depend on the abundance of drifting algae and whether it is reproductively viable. However, the ability of adult plants to successfully disperse long-distances by drifting is largely unknown, particularly for fucoids. The abundance, species composition, and reproductive status of drifting algae was examined by transect surveys around Kaikoura and Banks Peninsula. Abundance and species composition varied between sites, but all drifting algae that were in reproductive season, and had reproductive structures intact, were reproductively active. The reproductive longevity and viability of drifting and beach-cast Hormosira banksii, Durvillaea antarctica and Cytophora torulosa was compared with attached populations. Drifting algae remained reproductively viable, and fecundity did not differ from that of attached algae. Viable propagules were released from drifting algae for the duration of the experiments (H. banksii 57 days, D. antarctica 62 days, and C. torulosa 43 days). In contrast, beach-cast algae ceased to release propagules after 14 days. Dispersal by drifting relies on offshore transport after detachment. To determine the influence of wind and tidal currents on the nearshore transport of drifting algae, tagged H. banksii, D. antarctica, C. torulosa and GPS-tracked drifters were released from shore. Drifters generally moved in the direction of the prevailing wind, but some influence of tidal direction and bathymetry was detected. Offshore winds and outgoing tides were favourable for the offshore transport of surface drifting algae. Following dispersal and arrival at new locations, the distance between gametes may be important in determining the fertilisation success of dioecious species. Experiments testing the fertilisation success of H. banksii and D. antarctica, over increasing distances, showed that fertilisation success decreased with increasing distance between male and female gametes. Despite this, eggs were fertilised when male and female gametes were up to 2m apart, and sperm remained viable for 2 hours.
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Zubia, Arrieta Mayalen. "La valorisation industrielle des algues brunes invasives (fucales) de Polynésie française : étude prospective pour lutter contre leur prolifération et contribuer à la gestion durable de l'environnement récifal." Polynésie française, 2003. http://www.theses.fr/2003POLF0001.
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Une étude prospective des valorisations industrielles de deux algues brunes autochtones de Polynésie française, Sargassum mangarevense et Turbinaria ornata, a été réalisée afin de lutter contre leur prolifération et leur extension géographique. La masse de ces algues, fixées et dérivantes, est considérable sur les îles de Tahiti et de Moorea ce qui permet d'envisager leur exploitation. Les analyses biochimiques ont, par ailleurs, confirmé la qualité de ces algues pour leur valorisation dans différents secteurs industriels, en particulier leur richesse en minéraux, en fibres solubles, en protéines, en mannitol et en composés phénoliques et la présence de nombreux acides gras polyinsaturés. De plus, ces algues présentent une forte activité antioxydante et une activité contre la bactérie Staphylococcus aureus. Enfin, les essais de valorisation réalisés en agriculture et en cosmétique ont donné des résultats prometteursA prospective study of the industrial valorisation of two brown native algae (Fucales) of French Polynesia, Sargassum mangarevense and Turbinaria ornata, was done to fight against their growth and the geographic extension of populations. The mass of algae, attached and drifting, is very important in Tahiti and Moorea islands and the exploitation of this resource could be envisioned. Biochemical analyses have, moreover, confirmed the suitable quality of these algae for their valorisation in several industrial areas, especially, their richness in mineral salts, in soluble fibres, in proteins, in mannitol and in phenolic compounds and the presence of numerous polyunsatured fatty acids. Furthermore, these algae present a great antioxidant activity and they are active against the bacteria Staphylococcus aureus. Finally, trials in agriculture and cosmetic have given promissing results
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Blanfuné, Aurélie. "Le changement global en Méditerranée Nord Occidentale : forêt de Cystoseires, de Sargasses, encorbellement à Lithophyllum et bloom d'Ostreopsis." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4024/document.
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Dans la plupart des mers et des océans, la zone littorale est dominée par de grandes Phaeophyceae (Laminariales et Fucales) qui jouent un rôle écologique majeur dans la structuration et le fonctionnement de l’écosystème (fourniture d’habitats, de nourri ture, de frayères et de nurseries pour de nombreuses espèces). En Méditerranée, ce sont les espèces de Fucales appartenant aux genres Cystoseira C. Agardh et Sargassum C. Agardh qui sont les principales espèces structurantes du stade climacique de la végétation photophile de la zone littorale (de la surface jusqu’à 70-80 m de profondeur dans les eaux les plus claires). L’étude diachronique menée dans ce travail de thèse à partir des premières observations scientifiques exploitables (18ème siècle) est une première en Méditerranée sur autant de linéaire de côte (~ 2 970 km à l’échelle 2 500ème). Les résultats obtenus par l’analyse des données historiques et actuelles de distribution des Fucales le long des côtes françaises différent suivant les espèces étudiées, aussi bien en ce qui concerne l’état de conservation des populations que les causes impliquées dans leur régression. Dans l’ensemble, les forêts de Cystoseira et de Sargassum ont régressé de façon drastique en Méditerranée française. L’écosystème a souvent basculé (regime shift) vers un état stable alternatif (Multiple Stable State) de type barren ground, caractérisé par la dominance de macrophytes calcifiés encroûtants (corallinacées) et d’oursinsThroughout the world, coastal ecosystems are severely affected by the cumulative impact of increasing human pressure (e.g. destruction of habitats, pollution, non-indigenous species, overfishing, coastal aquaculture and global warming). Different foms of stress act over time and in unison, with a possible synergistic effect, on species, ecosystems and their ability to deliver ecosystem services. Along temperate rocky coasts worldwide, large canopy-forming kelps (Laminariales, Phaeophyceae, Ochrophyta) and fucoids (Fucales, Phaeophyceae, Ochrophyta) represent the dominant species in pristine environments. In the Mediterranean Sea, species of the genus Cystoseira C. Agardh and Sargassum C. Agardh are habitat-forming species dominating several assemblages from the littoral fringe down to the lower sublittoral zone (0 down to 70-80 m depth). The present diachronic study based on the first usable scientific observations (18th century) is the first in the Mediterranean to cover such a long stretch of coastline (~ 2970 km at 1/2 500 scale). The results obtained by the analysis of historical and current data on the distribution of Fucales along the French coast differ according to the species studied, both with regard to the conservation status of populations and the causes involved in their regression. The general loss of habitat-structuring species is worrying. We are witnessing a typical regime shift with a replacement of macroalgal forests by less structured algal assemblages dominated by Corallinales or by barren grounds dominated by encrusting species, filamentous algae and sea urchins
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Souza, Micheline Cristiane Rocha de. "Atividade antioxidante de fucanas e galactanas extra?das de algas marinhas." Universidade Federal do Rio Grande do Norte, 2008. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12532.
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Studies made with polysaccharides of seaweed have demonstrated that these present important biological and pharmacological activities. These composites had presented "scavenging" activity of free radicals, which is important in the mediation of the inflammatory process and in the pathology of diverse disease. Recently, this "scavenging" property has taken some researches to evaluate the antioxidant capacity from various polysaccharides. Considering the limited research with polysaccharides and knowing its largely employed by the pharmaceutical and foodstuffs industries, we have objective to verify the actions from fucans and galactans as antioxidants. The fucans are found in brown seaweed and the galactans (carrageenans) in red seaweed. The fucans were obtained from seaweed Padina gymnospora (F0.5 e F1.1 fractions), common to our coastline and one another fucan, fucoidan, was of origin commercial and extracted from seaweed Fucus vesiculosus. The λ, κ e ι carrageenans were also of origin commercial. The antioxidant activities were tested in superoxide and hydroxyl systems to generated free radicals and for the inhibition of the lipid peroxidation. The results obtained to inhibition of formation the superoxide radicals demonstrated that all polysaccharides presented scavenging activity of superoxide radicals. The fucoidan, F0.5 and F1.1 fractions presented IC50 of 0.058; 0.243 and 0.243 mg/mL, respectively, while IC50 of the λ, κ and ι carrageenans were 0.046; 0.112 and 0.332 mg/mL, respectively. The results to inhibition of formation the hydroxyl radicals demonstrated that all sample had low effect in the inhibition of the formation of these radicals, except the F0.5. For these radicals the IC50 were 0.157 and 0.353 mg/mL to the fucoidan and F1.1, respectively and 0.357; 0.335 and 0.281 mg/mL to λ, κ and ι carrageenans, respectively. All the samples were capacity to inhibition the peroxidation, it present the IC50 of 1.250; 2.753 and 2.341 mg/mL to fucoidan, F0.5 and F1.1, respectively. Already the λ, κ and ι carrageenans presented the IC50 of 2.697; 0.323 and 0.830 mg/mL, respectively. With these findings, we conclude that polysaccharides used in this study presented activity antioxidant, and that fucoidan and the λ carrageenan show a significant "scavenging" activity for the radicals superoxide and the κ carrageenan a significant inhibitory activity for the lipid peroxidation
Estudos feitos com polissacar?deos de algas t?m demonstrado que esses apresentam atividades biol?gicas e farmacol?gicas importantes. Estes compostos apresentaram atividade varredora de radicais livres, os quais s?o importantes na media??o do processo inflamat?rio e na patologia de diversas doen?as. Recentemente, essa propriedade varredora tem levado alguns pesquisadores a avaliar a capacidade antioxidante de diversos polissacar?deos. Considerando o reduzido n?mero de pesquisas com estes compostos e sabendo-se de seu largo emprego pela ind?stria farmac?utica e aliment?cia, objetivamos neste trabalho, verificar as a??es de fucanas e galactanas como antioxidantes. As fucanas s?o encontradas em algas marrons e as galactanas (carragenanas) em algas vermelhas. As fucanas foram obtidas da alga Padina gymnospora (fra??es F0,5 e F1,1), comum em nosso litoral, e uma outra fucana, o fucoidan, foi de origem comercial e extra?do da alga Fucus vesiculosus. As carragenanas λ, κ e ι tamb?m foram comerciais. A atividade antioxidante foi testada em sistemas geradores de radicais super?xidos e hidroxilas, e pela inibi??o da peroxida??o lip?dica. Os resultados obtidos para inibi??o da forma??o de radicais super?xidos demonstraram que todos os polissacar?deos apresentaram atividade varredora de radicais super?xidos. O fucoidan, as fra??es F0,5 e F1,1 apresentaram IC50 de 0,058; 0,243 e 0,243 mg/mL, respectivamente; enquanto o IC50 das carragenanas λ, κ e ι foi de 0,046; 0,112 e 0,332 mg/mL, respectivamente. Os resultados para inibi??o da forma??o de radicais hidroxilas demonstraram que todas as amostras inibiram a forma??o destes radicais, exceto a F0,5. Para estes radicais o IC50 foi de 0,157 e 0,353 mg/mL para o fucoidan e F1,1, e de 0,357; 0,335 e 0,281 mg/mL para carragenanas λ, κ e ι, respectivamente. Todas as amostras foram capazes de inibir a peroxida??o lip?dica com IC50 de 1,250, 2,753 e 2,341 mg/mL para o fucoidan, F0,5 e F1,1, respectivamente. J? as carragenanas λ, κ e ι apresentaram o IC50 de 2,697, 0,323 e 0,830 mg/mL, respectivamente. Com estes achados, conclu?mos que os polissacar?deos usados neste estudo apresentam atividade antioxidante, e que o fucoidan e a carragenana λ exibem uma significante atividade varredora para os radicais super?xido e a carragenana κ uma significante atividade inibit?ria da peroxida??o lip?dica
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Manuel, Theodore Llewellyn. "The biology and ecology of Bifurcaria brassiceaformis (Kütz) Barton (Phaeophyta, Fucales)." Master's thesis, University of Cape Town, 1991. http://hdl.handle.net/11427/22478.
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Summary in English.Bibliography: pages 146-169.
The biology, population dynamics, and the environmental tolerances (temperature and light) in laboratory culture, of the endemic intertidal South African fucoid Bifurcaria brassicaeformis (Kütz) Barton have been investigated. A general description is included of the morphology and anatomy, and comparisons made with that of other species in the genus. Studies on plants collected from contrasting habitats on the lowshore and from mid-shore pools revealed that while cortical thickness of vegetative uprights were similar for both habitats, medullary diameters were generally higher, corresponding to generally thicker uprights in the low-shore. Observations on the method of zygote attachment revealed that attachment of the species resembles that of the European Bifurcaria and Halidrys siliguosa which both also display delayed rhizoidal development and initially attach by means of a mucilage secretion of the zygote wall. Observations on receptacle anatomy revealed that size of conceptacles increase from the apex to the base of a receptacle.
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Hornby, Sarah Elizabeth. "Characterisation of pyrolysis mass spectrometry for use in marine algal systematics." Thesis, University of Newcastle Upon Tyne, 2000. http://hdl.handle.net/10443/948.
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Pyrolysis mass spectrometry (PyMS) is a rapid, automated analytical technique that is used for chemical and biological characterisation of organisms. It has been limited in its use outside the discipline of microbiology and has rarely been applied to the analysis of multi-cellular organisms. This study aimed to investigate the potential of using PyMS as a routine analytical tool to resolve problems in marine algal systematics. The technical constraints of PyMS were also examined. The effect of sample concentration proved to be an important consideration for the production of meaningful results. PyMS analysis of macroalgae from the order Fucales demonstrated that this technique was robust to the influence of environmental variability and challenged the assertion that it is limited to use as a phenotypic technique only. Characterisation of samples was also possible at the sub-species level. Experimentally induced variation among cultures of the diatom Skeletonema costatum, including silicate limitation, low salinity and reduced irradiance, was detectable by PyMS. PyMS is subject to technical limitations including day to day variability among spectral data and does not produce a permanent classification. This study showed that PyMS is a highly discriminatory, sensitive technique that is capable of resolving chemical and biological variability among marine algae.
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Camirand, Anne. "Glycosyltransferases from pea membranes : glucose and fucose incorporation into cell wall polysaccharides." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75336.
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Synthesis from UDP-($ sp{14}$C) glucose of charged lipid-linked glucosyl compounds by pea membranes was short-lived, and of very limited magnitude compared to the synthesis of 1,4- and 1,3-linked B-glucans. Lipid-linked monophosphoryl glucose was the only charged lipid formed at initial stages, and had properties similar to that of dolichol-monophosphoryl glucose. It exhibited no turnover during pulse-chase experiments. Lipid-linked pyrophosphoryl-glucose or -oligosaccharides were not detected. Coumarin inhibited the synthesis of SDS-soluble products and glucans, but not of the lipid-P-glucose. Transfer of the label from endogeneous lipid-P-($ sp{14}$C) glucose or from dolichol-P-($ sp3$H) glucose into non-lipid products was minimal. It was concluded that the lipid-linked phosphoryl saccharide formed from UDP-glucose was not an obligate intermediate in the formation of B-glucans in pea membranes.Fucose-containing lipid-linked intermediates were not involved in the biosynthesis of xyloglucans. However, pea microsomal membranes catalysed the transfer of $ lbrack sp{14}{ rm C} rbrack$-fucose from GDP-$ lbrack sp{14}$C) fucose, with or without added unlabelled UDP-glucose, UDP-xylose or UDP-galactose, to an insoluble product with properties characteristic of xyloglucan. After digestion of the ethanol-insoluble pellet with Streptomyces griseus endocellulase, $ lbrack sp{14}$C) fucose residues occurred exclusively in a fragment identified as the xyloglucan nonasaccharide, Glc$ sb4$ Xyl$ sb3$ Gal Fuc. By comparison, in incubations with UDP-$ lbrack sp3$H) xylose, the maximum size of labeled oligosaccharide found following cellulase digestion of products was an octasaccharide. In the presence of both GDP-$ lbrack sp{14}$C) -fucose and UDP-$ lbrack sp3$H) xylose, a nonasaccharide containing both labels was produced. Fucose and xylose residues were transferred rapidly to acceptor molecules of MW up to 300,000. Such products did not elongate detectably over 60 min of incubation. We concluded that the nonasaccharide subunit of xyloglucan was generated in vitro by transfucosylation to preformed acceptor chains, and that its synthesis was dependent on exogenous GDP-fucose.
Microsomal membranes were separated by rate-zonal centrifugation on renografin gradients. Transfer to xyloglucan of labelled fucose and xylose from GDP- ($ sp{14}$C) fucose and UDP- ($ sp{14}$C) xylose occurred mainly in dictyosome-enriched fractions. No transferase activity was detected in secretory vesicle fractions. Pulse-chase experiments using pea stem slices incubated with ($ sp3$H) fucose suggested that xyloglucan chains are fucosylated and their structure completed within the dictyosomes, before being transported to the cell wall by secretory vesicles.
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COLOMBO, GERALDINA. "PARTS CONSTITUTE A WHOLE. CHAMBER MUSIC (1907) FUCINA DEL MAGNUM OPUS JOYCIANO." Doctoral thesis, Università Cattolica del Sacro Cuore, 2014. http://hdl.handle.net/10280/3676.
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Questa tesi si propone di analizzare la raccolta poetica Chamber Music di James Joyce, pubblicata a Londra nel 1907. Al centro dei sei capitoli dello studio si colloca l’analisi testuale della raccolta, da cui emerge che essa costituisce il centro dell’opus joyciano nella sua interezza. Questa prima raccolta poetica, cioè, solitamente trascurata dalla critica letteraria joyciana, poiché ritenuta di minore pregio artistico rispetto ai successivi capolavori in prosa dello scrittore, pare porre le fondamenta del percorso tematico-espressivo che la prosa (lirica) di Joyce avrebbe poi sviluppato, evolvendosi lungo una traiettoria circolare, ricca di richiami inter/intra-testuali. Si è riconosciuta, in particolare, nella struttura interna della raccolta, una progressiva integrazione di più codici letterari-culturali, risultante in una compresenza di livelli semantico-espressivi, significativa del sincretismo culturale-stilistico tipicamente joyciano. La vicenda di Chamber Music, così, non è riletta solo quale storia d’amore stereotipata, sull’esempio dei canzonieri elisabettiani, ma anche come processo di evoluzione personale e stilistica del protagonista, lover e poet insieme, che rappresenta il primo alter ego letterario joyciano.This dissertation aims to analyse James Joyce’s first poetic collection, Chamber Music, published in London in 1907. The core of the six chapters of the study is represented by the textual analysis of the collection, from which we infer that Chamber Music constitutes the nucleus of the Joycean opus in its entirety. The collection, usually neglected by Joycean criticism, as it is regarded as the minor aspect of Joyce’s literary production, if compared to the writer’s recognised prose masterpieces, seems to lay the foundations of the thematic and expressive course then developed by Joyce’s (lyrical) prose, evolving along a circular trajectory, rich in inter/intra-textual references. In particular, within the internal structure of the collection, we did identify a progressive integration of more literary-cultural codes, resulting in the coexistence of several semantic-expressive levels, representative of Joyce’s characteristic cultural-stylistic syncretism. The plot of Chamber Music, then, is not simply read as a stereotyped love affair, modelled on Elisabethan songbooks, but also as the process of personal and stylistic evolution of its protagonist, both lover and poet, being representative of Joyce’s first literary alter ego. KEYWORDS: James Joyce; Chamber Music; poetry; lyrical prose.
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Ferreira, Luciana Garcia. "Análise estrutural de polissacarídeos potencialmente bioativos : fucanas sulfatadas de algas pardas (Phaeophyta) /." Curitiba, 2007. http://200.17.209.5:8000/cgi-bin/gw_42_13/chameleon.42.13a?host=localhost%201111%20DEFAULT&sessionid=VTLS&function=CARDSCR&search=KEYWORD&pos=1&u1=12101&t1=233654.
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Orientadora: Maria Eugênia Duarte NosedaCo-orientador: Miguel D.Noseda
Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Bioquímica. Defesa: Curitiba, 2007
Inclui bibliografia e anexos
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Rousseau, Florence. "Phylogénie moléculaire des fucales et tendances évolutives au sein des algues brunes." Paris, Muséum national d'histoire naturelle, 1999. http://www.theses.fr/1999MNHN0003.
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Ce travail conduit à une conception nouvelle des relations phylogénétiques au sein des algues brunes et, plus particulièrement, des fucales. Des phylogénies moléculaires ont été établies puis confrontées aux caractères morphologiques et biochimiques disponibles. Pour cela, une zone génétique adaptée à la problématique a d'abord été recherchée. Les domaines D1 et D2 du gène de l’ARN de la grande sous-unité ribosomale (LSU) ont été utilisés pour la première fois chez les algues brunes et sont apparus particulièrement adaptes pour les reconstructions phylogénétiques au sein des fucales. Pour les analyses concernant l'ensemble de la classe des phacophyceae, une combinaison des séquences de l'extrémité 5 de la LSU (environ 600 nucléotides) et de l'extrémité 3 du gène de l’ARN de la petite sous-unité ribosomale (SSU) (450 nucléotides) a été utilisée. Les résultats obtenus ont permis de présenter une synthèse cohérente entre les arbres phylogénétiques moléculaires et les caractères morphologiques et biochimiques. Ainsi, les caractères ultrastructuraux sont apparus comme les plus pertinents au plan systématique ; l'évolution des principaux caractères morphologiques a été discutée ; une hypothèse d'évolution du cycle de certaines ectocarpales a, notamment, été proposée. Ce travail a abouti à plusieurs remaniements de la classification. L'ordre des fucales a été redéfini pour y inclure les ordres des durvillaeales et des notheiales. Au sein des fucales, des relations phylogénétiques entre les familles ont pu être établies. Les seirococcaceae se situent à la base des fucales. Les autres familles constituent deux clades principaux au sein desquels la place des durvillaeaceae doit être confirmée. Le premier clade est constitué de la famille des durvillaeaceae, taxon frère de bifurcariopsis + hymanthalia, taxons frères de hormosira + xiphophora + les fucaceae ; le second est forme de notheia taxon frère des cystoseiraceae + sargassaceae. La famille des cystoseiraceae est apparue paraphylétique par rapport aux sargassaceae. La famille des cystoseiraceae a donc été incluse dans celle des sargassaceae sensu de toni 1895. Les familles des durvillaeaceae, fucaceae, himanthaliaceae, hormosiraceae, notheiaceae et seirococcaceae ont été confirmées. Les genres bifurcariopsis et xiphophora devraient constituer chacun une famille propre. A l'échelle de l'ensemble de la classe, l'ordre des ectocarpales a été redéfini, sur la base de la présence de pyrénoïdes exserts. Cet ordre regroupe donc les algues classiquement placées dans les chordariales, les dictyosiphonales, les ectocarpales sensu stricto et les scytosiphonales, tandis que les algues dépourvues de pyrénoïde exsert, parfois placées dans les ectocarpales sensu lato, comme les tilopteridales, les ralfsiales sensu nakamura 1972, les scytothamnales, asteronema, asterocladon et bachelotia, en ont été exclues. Les ordres des desmarestiales, des dictyotales, des fucales, des scytothamnales et des sphacelariales sont monophylétiques. Les dictyotales, les sphacelariales et syringoderma forment un ensemble monophylétique, cohérent avec les données morphologiques. Les laminariales et les tilopteridales sont polyphyletiques. Saccorhiza, chorda et halosiphon sont exclus des laminariales, aussi bien sur des bases morphologiques que moléculaires. Ascoseira, asterocladon, bachelotia, cutleria, nemoderma, phaeosiphoniella et sporochnus constituent des lignées séparées, mais les relations entre ces différentes lignées ne sont pas résolues par les analyses moléculaires
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Coimbra, Cíntia Schultz. "Inferências filogenéticas na ordem Fucales (Phaeophyceae), com ênfase no gênero Sargassum C. Agardh do Atlântico Sul." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-22082007-101454/.
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O gênero Sargassum C. Agardh (Sargassaceae) constitui um dos mais representativos dentre os 41 gêneros da ordem Fucales (Phaeophyceae, Heterokontophyta), é amplamente distribuído nas regiões tropicais e subtropicais do globo e é considerado um importante componente da flora marinha. Devido ampla variabilidade fenotípica é considerado um dos gêneros de taxonomia mais complexa dentre as algas pardas, como são popularmente conhecidos os representantes da classe Phaeophyceae. A filogenia da ordem Fucales é bastante discutida para gêneros do hemisfério norte, mas ainda pouco elucidada. Os estudos de filogenia referentes ao gênero Sargassum são escassos, limitando-se a poucos marcadores moleculares, com baixa resolução no âmbito inter-específico e limitados à espécies de ocorrência nos oceanos Indo-Pacífico e Atlântico Norte. Nenhum estudo filogenético incluí espécies do Atlântico Sul para este gênero. Este estudo é pioneiro na análise de seqüências de diferentes marcadores moleculares para espécies do Atlântico Sul. Neste estudo, foram seqüenciados completamente os marcadores moleculares nucleares SSU rDNA e ITS2 para os táxons infra-genéricos Sargassum cymosum var. cymosum, S. cymosum var. nanum, S. furcatum, S. stenophyllum e S. vulgare. Todas as seqüências obtidas para ambos os marcadores apresentaram 100% de identidade entre os táxons analisados. Foram feitas seqüências também para o marcador molecular plastidial rbcL (parcial) e espaçador rbcLS para as espécies S. filipendula, S. stenophyllum e S. vulgare que resultaram também em 100% de identidade. Análises filogenéticas de cada um dos marcadores moleculares, incluindo nossas seqüências e aquelas disponíveis no Genbank e geradas pelos métodos de inferência \"Neigbour-joining\", máxima parcimônia e máxima verossimilhança se apresentaram robustas e corroboram outros resultados descritos na bibliografia referente a ordem Fucales e ao gênero Sargassum. Entretanto, tais resultados fornecem um forte indício da necessidade de busca de marcadores moleculares eficientes, devidamente respaldados por estudos de hibridação in vitro, dados ecológicos e de biogeografia para um melhor entendimento acerca das espécies ocorrentes na costa brasileira.The genus Sargassum C. Agardh (Sargassaceae) is one of the most conspicuous among the 41 genera of the order Fucales (Phaeophyceae, Heterokontophyta). The genus has a broad distribution in the tropical and subtropical regions of the world, and is considered an important component of the marine flora. Due to a high phenotipic variation, the taxonomy of the genus is considered of the most complex among the brown seaweeds, as are known the representatives of the class Phaeophyceae. The phylogeny of the order Fucales was studied for the North Hemisphere genera, but is still not well understood. The phylogenetic studies of the genus Sargassum are scarce and limited to a few molecular markers, presenting low resolution for inter-specific analysis and are available only for species from the Indo-Pacific and the North Atlantic. There are no phylogenetic studies including species from the South Atlantic for the genus. This study is the first to analyze sequences from different molecular markers for species from the South Atlantic. In this study, the nuclear SSU rDNA and ITS2 were completely sequenced for the infra-generic taxa Sargassum cymosum var. cymosum, S. cymosum var. nanum, S. furcatum, S. stenophyllum and S. vulgare. All the sequences for both markers presented 100% identity among analyzed taxa. Sequences were also obtained for the chloroplast marker rbcLS, including parcial rbcL and the spacer region rbcLS for the species S. filipendula, S. stenophyllum and S. vulgar. These sequences also presented 100% identity among analyzed taxa. Phylogenetic analysis of each of the molecular markers, including our sequences together with other sequences available in the Genbank and generated by the inference methods Neigbour-joining, maximum parsimony and maximum likelihood were robust and similar to other results described in the literature for the order Fucales and the genus Sargassum. Nonetheless, these results are an indicative of the need for more efficient molecular markers, associated with data from in vitro hibridization, ecology and biogeography for a better understanding about the taxa occurring on the brazilian coast.
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Ponce, Nora M. A., Analía V. Uhrich, María L. Flores, and Carlos A. Stortz. "Extracción secuencial de los polisacáridos del alga parda Adenocystis utricularis." Revista de Química, 2017. http://repositorio.pucp.edu.pe/index/handle/123456789/100567.
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Adenocystís utrícularís (familia Adenocystaceae; orden Ectocarpales sensu lato) es un alga parda que crece sobre el sustrato rocoso en las costas patagónicas del Atlántico Sur. La extracción de sus polisacáridos fue llevada a cabo por tratamiento secuencial con etanol al 80 % frío y caliente, solución de cloruro de calcio al 2% frío y caliente, y finalmente con ácido clorhídrico diluido (pH 2) a 70ºC. El manitol fue el hidrato de carbono mayoritario en el extracto etanólico a temperatura ambiente, mientras que los fucoidanos y las proteínas fueron principalmente extraídos con etanol a 70°C. Ambos extractos evidenciaron además la presencia de compuestos de naturaleza fenólica. Los demás extractos mostraron altas cantidades de hidratos de carbono y menores de proteínas: en todos ellos el principal monosacárido constituyente fue fucosa, con pequeñas proporciones de galactosa y manosa. Los ácidos urónicos y grupos ésteres sulfato fueron también constituyentes de los extractos.
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Lamote, Morgane. "Suivi du recrutement des embryons de fucales dans leur milieu naturel et influence des stress de dessiccation et d'excès de lumière sur leur développement." Lille 1, 2002. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2002/50376-2002-339.pdf.
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La zone intertidale est un environnement extrême en raison de l'alternance de périodes d'émersion et d'immersion. Les organismes benthiques comme les algues brunes doivent être capables de coloniser rapidement cette zone et de survivre dans ces conditions difficiles. Ce travail consiste à étudier, d'une part, la colonisation du milieu par ces algues et, d'autre part, l'effet des paramètres climatiques sur le développement de leurs jeunes organismes dans l'estuaire du St Laurent (Canada). (1) Des dénombrements d'embryons sur des substrats artificiels permettent d'observer une grande variabilité spatiale et temporelle du recrutement , indépendant du nombre d'adultes matures mais conditionné par des facteurs climatiques. Le taux de mortalité s'avère plus important sur les surfaces rocheuses exposées et dans les cuvettes que sous la canopée. (2) Par des mesures de fluorescence chlorophylienne en laboratoire, nous avons suivi la mise en place de l'appareil photosynthétique de ces embryons qui s'avère fonctionnel après six jours de développement. (3) Des mesures de fluorescence chlorophylienne réalisées sur le terrain montrent que l'activité photosynthétique de jeunes embryons de trois espèces différentes, confrontés à quatre conditions météorologiques définies, déclinent inégalement durant les marées basses. Ces différences de sensibilité au stress déterminent l'emplacement de ces trois espèces sur l'estran, celle qui occupe le niveau bathymétrique le plus élevé étant capable de maintenir une activité photosynthétique plus longtemps au cours d'une émersion que celles qui vivent à des niveaux inférieurs. De plus, pour chaque espèce, les embryons qui se développent sous la canopée sont moins affectés durant la marée basse mais, en raison de la faible irradiance, leur photosynthèse est plus faible. (4) Durant la marée basse, un gradient dans la rapidité de dégradation de l'activité photosynthétique de jeunes thalles situés à cinq niveaux différents sur une paroi verticale a été mis en évidence par des mesures de fluorescence chlorophylienne, les thalles des niveaux supérieurs étant les plus affectés. Cette altération est étroitement corrélée à un gradient de dessiccation qui apparaît comme un des facteurs déterminant l'emplacement des algues sur l'estran.
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Janocka, Déborah. "Culture in vitro de la Fucale Pelvetia canaliculata : applications à la production de biomasse algale et à la cryoconservation des semences." Caen, 2009. http://www.theses.fr/2009CAEN2073.
Full textAbstract:
Pelvetia canaliculata est une Phéophycée commune des côtes de la Manche. Son exploitation industrielle n’est pas actuellement envisageable en raison de ses peuplements limités nécessitant alors l’élaboration de systèmes de micropropagation. La production de biomasse algale de Pelvetia a été développée à partir des cellules somatiques (protoplastes, explants) et des semences naturelles (zygotes) en fonction de la période du cycle de développement. La cryoconservation des zygotes permet d’envisager la constitution d’un stock de semences disponible toute l’année. La mise au point d’une solution enzymatique a permis la production en routine de protoplastes avec des rendements atteignant 107 protoplastes. G-1 de matière fraîche à partir des apex. L’étude des paramètres physicochimiques de leur régénération a abouti à la formation de la paroi squelettique puis au déclenchement de bourgeonnements et de divisions cellulaires traduisant une reprise du programme morphogénétique. La culture d’explants sur milieu solide a induit la néoformation de bourgeons à partir des différentes zones du thalle, notamment de la zone sous-apicale. L’amélioration du protocole a été initiée. Les facteurs contrôlant la libération synchrone et massive des gamètes de Pelvetia et la production des zygotes ont été identifiés. La séquence du développement embryonnaire in vitro a été décrite jusqu’au stade plantule mettant en évidence l’absence de polarité du zygote et d’une première division asymétrique. Le protocole de cryoconservation des zygotes mis au point permet d’obtenir une viabilité des embryons après réchauffement d’environ 60% au bout de 28 jours de culture et leur régénération en plantulesPelvetia canaliculata is a common Phaeophyceae of the French Channel coast. For the time being its industrial exploitation is not possible due to its restricted wild populations it is requiring the elaboration of systems of micropropagation. The production of algal biomass of Pelvetia has been developed from somatic cells (protoplasts, tissue culture) and from natural seeds (zygotes) according to the period of the life cycle. The cryopreservation of zygotes has been also developed allowing to the establishment of a seedstock available throughout the year for macroalgal culture. The composition of an enzyme solution has been determined in order to produce reliably protoplasts from apical regions of the thallus, protoplasts yields reaching 1 x 107 protoplasts per gram of fresh weight. The study of the physicochemical parameters of the protoplast regeneration has led to the synthesis of the cell wall followed by buddings and cell divisions indicating a new start of a morphogenetic program. Tissue culture on solid medium induced buds regeneration from the different regions of the thallus, particularly from subapical explant. The improvement of the protocol has been initiated. The factors involved in the synchronous and massive discharge of gametes of Pelvetia and the production of zygotes have been identified. The sequence of the embryonic development in vitro has been described until the plantlet stage revealing the absence of a zygotic polarity and of a first asymmetric division. A protocol of cryopreservation of zygotes has been established. The viability of the cooled embryos after thawing was about 60% after 28 days of culture and they developed into plantlets
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Wisbrun, Natali Kristina [Verfasser]. "Klonierung und funktionelle Expression von Enzymen des L-Fucose-Stoffwechsels / Natali Kristina Wisbrun." Berlin : Freie Universität Berlin, 2007. http://d-nb.info/102241254X/34.
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