• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 1
  • Tagged with
  • 7
  • 7
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Population dynamics and endophytic flora of Chondrus crispus (Rhodophyta) : a temporal study

Plumb, Jeremy January 1999 (has links)
A temporal long-term study of the population structure and dynamics of the red alga Chondrus crispus at Lilstock, Somerset (Bristol Channel), the British Isles, and an investigation of its associated green and brown endophytic algal flora were undertaken from January 1994 to September 1996. The population of C. crispus was composed of plants which consisted of a basal holdfast from which arose numerous fronds in varying stages of development, with or without reproductive fronds (cystocarps or tetrasporangial sori). Plants were found with only gametophyte (haploid) or tetrasporophyte (diploid) fronds, whereas other plants described as mixed clumps consisted of gametophyte and tetrasporophyte fronds associated with the same basal disc. New plants entered the population and others were lost throughout the study. Individual plant longevity ranged from <46 days to >927 days. The monthly gametophyteitetrasporophyte ratio did not significantly deviate from 1:1, and within the population there was a stable long-lived core of plants, with a gametophyte:tetrasporophyte ratio of 1:1. Gametophyte plants with cystocarps had a significantly greater dry mass and contained a significantly greater number of fronds than tetrasporophyte plants with sori. Significantly higher numbers of tetrasporophytes had reproductive structures (sori) than gametophyte plants (cystocarps) during summer months (namely May, June and July). Both recruitment from spores and frond regeneration from remnant basal discs played an important role in maintaining the population structure. At least 6 green algal taxa including Acrochaete heteroclada, A. operculata, A. repens, A. viridis, Enteromorpha sp(p) and Pseudoendoclonium sp., and at least one brown algal taxon assigned to the genus Streblonema were found in association with gametophyte and tetrasporophyte C. crispus plants with cystocarps and sori, respectively. Spatial distribution of these algae within host tissues ranged from epiphytic through epiendophytic to endophytic. Of the C. crispus plants collected the frequency of plants infected with endophytic algae was reported to reach 95%. Infection by brown algae was rarely found without an associated green algal infection. It is hypothesised that a self-purging natural purification process of infected C. crispus fronds helps rid the plants and population of diseased fronds. It is suggested that it is primarily through the retention of the basal discs that C. crispus is an ecologically successful species.
2

Estudo químico e biológico de fungos endofíticos associados com a alga vermelha Dichotomaria marginata (Galaxauraceae)

Valadão, Isabella Barros [UNESP] 10 December 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-12-10Bitstream added on 2014-06-13T19:58:56Z : No. of bitstreams: 1 valadao_ib_me_araiq_parcial.pdf: 494280 bytes, checksum: f71a3fc25bfa0b073162ad9acbc99940 (MD5) Bitstreams deleted on 2014-11-14T12:16:52Z: valadao_ib_me_araiq_parcial.pdf,Bitstream added on 2014-11-14T12:17:42Z : No. of bitstreams: 1 000713243.pdf: 1355332 bytes, checksum: 8d17f83281f9a02e2ab6dbfd4fd13b99 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho teve como objetivo principal a obtenção de substâncias bioativas apartir do estudo químico/biológico do extrato bruto produzido pelo fungo endofíticoHypoxylonsp., isolado dos talos da alga vermelhaDichotomariamarginata. Este fungofoi cultivado em meio sólido (arroz) fornecendo o extrato bruto em AcOEt, após maceração, filtração a vácuo e evaporação do solvente. Neste avaliou-se a produção metabólica em CCDC, CLAE-DAD e RMN de 1H e foi submetidoabioensaios para avaliar a seu potencial antifúngico in vitro contra patógenos humanos e fitopatógenos, onde demonstrou ser promissor. Fracionamento em coluna de sílica gel de fase reversa (C-18) resultou no isolamento de três substâncias da classe das antraquinonas: 1,5-dimetoxi-2,6- dihidroxi-antraquinona, 1,5,6-trimetoxi-2-hidroxi-antraquinona, 1,2,5,6-tetrametoxiantraquinona, sendo este o primeiro relato de antraquinonas isoladas do fungo Hypoxylon sp.. O extrato bruto do fungo endofíticoHypoxylonsp. apresentoumoderada atividade antifúngica frente ao patógeno humano Cryptococcusneoformans e frente ao fitopatógenoCladosporiumsphaerospermum. Os resultados do trabalho reforçam a importância do estudo de microrganismo como fonte de metabolitos secundários / The present work main objective is to obtain bioactive substances from the chemical/biological study of crude extract produced by the endophytic fungus Hypoxylon sp., isolated from the stems of the seaweed Dichotomariamarginata. This endophyte was cultivated in solid medium(rice) providing the crude extract in AcOEt, after vacuum filtration and solvent evaporation. The metabolic production of this extracts was evaluated in CCDC, HPLC-DAD and 1H-NMR and the extracts were subjected to bioassays to evaluation the antifungal potential against human pathogens and phytopathogens, which proved to be promising. The crude extract was fractionated on a column of silica gel reverse phase (C-18) resulting in the isolation of three substances, 1,5-dimethoxy-2,6-dihydroxy-anthraquinone, 1,5,6-trimethoxy-2-hydroxy-anthraquinone, 1,2,5,6-tetramethoxy-anthraquinone. This was the first report of isolated anthraquinones from Hypoxylon sp.The crude extract of endophytic fungus Hypoxylon sp. showed moderate antifungal activity against the human pathogen Cryptococcus neoformans and against the phytopathogensCladosporiumsphaerospermum. The results of the study reinforce the importance of the study of microorganisms as a source of secondary metabolites
3

Estudo químico e biológico de fungos endofíticos associados com a alga vermelha Dichotomaria marginata (Galaxauraceae) /

Valadão, Isabella Barros. January 2012 (has links)
Orientador: Marcia Nasser Lopes / Banca: Vera Lucia Garcia Rehder / Banca: Sandra Imaculada Maintinguer / Resumo: O presente trabalho teve como objetivo principal a obtenção de substâncias bioativas apartir do estudo químico/biológico do extrato bruto produzido pelo fungo endofíticoHypoxylonsp., isolado dos talos da alga vermelhaDichotomariamarginata. Este fungofoi cultivado em meio sólido (arroz) fornecendo o extrato bruto em AcOEt, após maceração, filtração a vácuo e evaporação do solvente. Neste avaliou-se a produção metabólica em CCDC, CLAE-DAD e RMN de 1H e foi submetidoabioensaios para avaliar a seu potencial antifúngico in vitro contra patógenos humanos e fitopatógenos, onde demonstrou ser promissor. Fracionamento em coluna de sílica gel de fase reversa (C-18) resultou no isolamento de três substâncias da classe das antraquinonas: 1,5-dimetoxi-2,6- dihidroxi-antraquinona, 1,5,6-trimetoxi-2-hidroxi-antraquinona, 1,2,5,6-tetrametoxiantraquinona, sendo este o primeiro relato de antraquinonas isoladas do fungo Hypoxylon sp.. O extrato bruto do fungo endofíticoHypoxylonsp. apresentoumoderada atividade antifúngica frente ao patógeno humano Cryptococcusneoformans e frente ao fitopatógenoCladosporiumsphaerospermum. Os resultados do trabalho reforçam a importância do estudo de microrganismo como fonte de metabolitos secundários / Abstract: The present work main objective is to obtain bioactive substances from the chemical/biological study of crude extract produced by the endophytic fungus Hypoxylon sp., isolated from the stems of the seaweed Dichotomariamarginata. This endophyte was cultivated in solid medium(rice) providing the crude extract in AcOEt, after vacuum filtration and solvent evaporation. The metabolic production of this extracts was evaluated in CCDC, HPLC-DAD and 1H-NMR and the extracts were subjected to bioassays to evaluation the antifungal potential against human pathogens and phytopathogens, which proved to be promising. The crude extract was fractionated on a column of silica gel reverse phase (C-18) resulting in the isolation of three substances, 1,5-dimethoxy-2,6-dihydroxy-anthraquinone, 1,5,6-trimethoxy-2-hydroxy-anthraquinone, 1,2,5,6-tetramethoxy-anthraquinone. This was the first report of isolated anthraquinones from Hypoxylon sp.The crude extract of endophytic fungus Hypoxylon sp. showed moderate antifungal activity against the human pathogen Cryptococcus neoformans and against the phytopathogensCladosporiumsphaerospermum. The results of the study reinforce the importance of the study of microorganisms as a source of secondary metabolites / Mestre
4

Chemical Investigation of the Antarctic Marine Invertebrates Austrodoris kerguelenensis &#38; Dendrilla membranosa and the Antarctic Red Alga Gigartina skottsbergii

Maschek, John Alan 01 January 2011 (has links)
The marine realm and, in particular, the Antarctic benthos is largely unexplored and understudied. The chemical investigation reported herein reveals not only the biodiversity, but how that biodiversity manifests remarkable chemical diversity. In our continuing study of the nudibranch Austrodoris kerguelenensis, we have isolated a diverse suite of diterpenoid glyceride esters, palmadorins D - S (2.32 - 2.47), one of which is the first reported halogenated diterpene from a dorid nudibranch. Utilizing genomic data from collaborators, we have investigated the chemical diversity from phylogenetically unique specimens collected in close proximity to one another. Chemical groupings based on comparison of LC/MS metabolite fingerprints from individual organisms correlated well to the genetic data. Our research shows that A. kerguelenensis specimens from the same phylogroups elaborate near identical metabolite profiles to each other, but distinct from other phylogroups. Dendrilla membranosa is a dominant demosponge that prior studies have shown is rarely preyed upon and deters feeding against amphipods, the principal mesograzers of the Western Antarctic Peninsula. To assess the defensive nature of the pure compounds, artificial food pellets spiked with membranolides were evaluated in a feeding assay against the omnivorous amphipod Gondogeneia antarctica whereby only artificial pellets containing membranolide exhibited significant feeding deterrence. The research reported herein demonstrates that membranolides C and D were originally misassigned. Reevaluation of new extracts evolved additional fused furan membranolides G and H, and allowed for complete characterization of the four epimers. Extraction of sponge in CD3OD resulted in incorporation of a deuterated methyl group into fragment ions as evidenced from LC/MS chromatograms. Further chemical investigation of D. membranosa without the use of methanol revealed that these non-natural products arise from aplysulphurin, a known compound originally isolated from the sponge Aplysilla sulphurea, but later isolated from D. membranosa. These studies emphasize the importance of exploring the marine realm for the presence of antiviral compounds, not only for identification of small molecules but also as a source of potent macromolecules. Subfractions from Gigartina skottsbergii possesses strong anti-influenza activity toward both the A/Wyoming/03/2003 (H3N2) and A/California/04/2009 (H1N1) virus with EC50 values in the range of 5 to 10 μg/mL. The virus-inhibitory effect was selective, dose-dependent, strain-specific and the virus induced cytopathogenic effect (CPE) was reduced at non-toxic concentrations of the extract.
5

Isolation, Purification and Characterization of Photosynthetic Membrane Proteins from Galdieria sulphuraria and Chlamydomonas reinhardtii

January 2010 (has links)
abstract: In oxygenic photosynthesis, Photosystem I (PSI) and Photosystem II (PSII) are two transmembrane protein complexes that catalyze the main step of energy conversion; the light induced charge separation that drives an electron transfer reaction across the thylakoid membrane. Current knowledge of the structure of PSI and PSII is based on three structures: PSI and PSII from the thermophilic cyanobacterium Thermosynechococcus elonagatus and the PSI/light harvesting complex I (PSI-LHCI) of the plant, Pisum sativum. To improve the knowledge of these important membrane protein complexes from a wider spectrum of photosynthetic organisms, photosynthetic apparatus of the thermo-acidophilic red alga, Galdieria sulphuraria and the green alga, Chlamydomonas reinhardtii were studied. Galdieria sulphuraria grows in extreme habitats such as hot sulfur springs with pH values from 0 to 4 and temperatures up to 56°C. In this study, both membrane protein complexes, PSI and PSII were isolated from this organism and characterized. Ultra-fast fluorescence spectroscopy and electron microscopy studies of PSI-LHCI supercomplexes illustrate how this organism has adapted to low light environmental conditions by tightly coupling PSI and LHC, which have not been observed in any organism so far. This result highlights the importance of structure-function relationships in different ecosystems. Galdieria sulphuraria PSII was used as a model protein to show the amenability of integral membrane proteins to top-down mass spectrometry. G.sulphuraria PSII has been characterized with unprecedented detail with identification of post translational modification of all the PSII subunits. This study is a technology advancement paving the way for the usage of top-down mass spectrometry for characterization of other large integral membrane proteins. The green alga, Chlamydomonas reinhardtii is widely used as a model for eukaryotic photosynthesis and results from this organism can be extrapolated to other eukaryotes, especially agricultural crops. Structural and functional studies on the PSI-LHCI complex of C.reinhardtii grown under high salt conditions were studied using ultra-fast fluorescence spectroscopy, circular dichroism and MALDI-TOF. Results revealed that pigment-pigment interactions in light harvesting complexes are disrupted and the acceptor side (ferredoxin docking side) is damaged under high salt conditions. / Dissertation/Thesis / Ph.D. Biochemistry 2010
6

Caracterização estrutural e atividade anti-inflamatória em modelo de aterosclerose em camundongos de uma galactana sulfatada da alga vermelha Acanthophora muscoides / Structural characterization and anti-inflammatory activity in asterosclerose model in mice of a sulfada galactan red algae Acanthophora muscoide

Quinderé, Ana Luiza Gomes January 2015 (has links)
QUINDERE, Ana Luiza Gomes. Caracterização estrutural e atividade anti-inflamatória em modelo de aterosclerose em camundongos de uma galactana sulfatada da alga vermelha Acanthophora muscoides. 2015. 152 f. Tese (Doutorado em Bioquímica)-Universidade Federal do Ceará, Fortaleza, 2015. / Submitted by Vitor Campos (vitband@gmail.com) on 2016-09-01T22:42:17Z No. of bitstreams: 1 2015_tese_algquindere.pdf: 1798137 bytes, checksum: c21776a201b808de159ff9bc73b36644 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-09-02T21:05:07Z (GMT) No. of bitstreams: 1 2015_tese_algquindere.pdf: 1798137 bytes, checksum: c21776a201b808de159ff9bc73b36644 (MD5) / Made available in DSpace on 2016-09-02T21:05:07Z (GMT). No. of bitstreams: 1 2015_tese_algquindere.pdf: 1798137 bytes, checksum: c21776a201b808de159ff9bc73b36644 (MD5) Previous issue date: 2015 / Sulfated galactans from red marine algae are polysaccharides with heterogeneous structures that have presented a variety of potentially therapeutic biological effects including anticoagulant, anti-thrombotic and anti-inflammatory, however, their potential activity as anti-inflammatory agent in the treatment of atherosclerosis, a chronic inflammatory disease that culminates with thromboembolic disorders, has not been previously studied. Furthermore, experimental data from animal models and clinical studies support connections between the hemostasis and inflammation in atherogenesis. These interfaces among inflammation and thrombogenesis have been suggested as targets for pharmacological intervention to reduce disease progression. Herein, we determined the chemical structure of a novel sulfated galactan obtained from the marine alga Acanthophora muscoides (fraction AmII) and analysed its effect on a mice model of atherosclerosis in 10-week aged apolipoprotein E deficient (ApoE−/−) mice under high-cholesterol diet for additional 4 or 11 weeks. Fraction AmII (10 mg/kg) or Vehicle were subcutaneously injected from week 2 until 4 of the diet or from week 6 until week 11 of the diet. In vitro assays of macrophage chemotaxis were also performed. The structure of the complex sulfated galactan was characterized by solution nuclear magnetic resonance and its molecular mass was determined by gel permeation chromatography and polyacrylamide gel electrophoresis. The sulfated galactan from A. muscoides presents a molecular mass of ~ 20kDa and an alternating 4-linked α-galactose and 3-linked β-galactose, substituted with sulfate esters and methyl ethers along with the occurrence of 3,6-anhydro-α-galactoses. In the 4 weeks diet model, treatment with fraction AmII did not alter the atherosclerotic plaque size, and other intraplaque features of vulnerability (such as lipid, neutrophil, macrophage, MMP-9 and collagen contents). In the 11 weeks diet model, treatment with fraction AmII reduced intraplaque macrophage and tissue factor (TF) content as compared to Vehicle-treated animals. Intraplaque TF co-localized and positively correlated with macrophage rich-areas. No changes on atherosclerotic plaque size, and other intraplaque features of vulnerability, such as lipid, neutrophil, MMP-9 and collagen contents, were observed. Moreover, mRNA expression of MMPs, chemokines and genetic markers of Th1/2/reg/17 lymphocyte polarization within mouse aortic arches and spleens was not affected by AmII treatment. In vitro, treatment with AmII dose-dependently reduced macrophage chemotaxis without affecting TF production. Overall, the chronic AmII treatment was well tolerated. In conclusion, our results indicate that AmII treatment reduced intraplaque macrophage content, by impacting on cell recruitment, and, concomitantly, intraplaque TF content of potential macrophage origin in atherosclerotic mice. / As galactanas sulfatadas obtidas de algas marinhas vermelhas são polissacarídeos de estruturas heterogêneas que têm apresentado uma variedade de efeitos biológicos, potencialmente terapêuticos, incluindo anticoagulante, antitrombótico e anti-inflamatório. No entanto, a sua atividade potencial como agente anti-inflamatório para o tratamento de aterosclerose, uma doença inflamatória crônica que culmina com distúrbios tromboembólicos, não foi previamente estudada. Além disso, dados experimentais de modelos animais e estudos clínicos suportam conexões entre a hemostasia e inflamação na aterogênese. Estas interfaces entre inflamação e trombogênese têm sido sugeridas como alvos para intervenção farmacológica visando reduzir a progressão da doença. No presente trabalho, determinou-se a estrutura química de uma nova galactana sulfatada obtida da alga marinha Acanthophora muscoides (fração AmII) e analisou-se seu efeito sobre um modelo de aterosclerose em camundongos deficientes em apolipoproteína E (ApoE−/−) de 10 semanas submetidos a dieta de alto teor de colesterol durante mais 4 ou 11 semanas. A fração AmII (10 mg/kg) ou veículo (salina) foram injetados por via subcutânea durante a segunda até a quarta semana de dieta ou a partir da sexta até a décima primeira semana de dieta. Ensaios in vitro de quimiotaxia de macrófagos também foram realizados. A estrutura da galactana sulfatada complexa foi caracterizada por ressonância magnética nuclear em solução e a sua massa molecular foi determinada por cromatografia de permeação em gel e eletroforese em gel de poliacrilamida. A fração AmII apresentou uma massa molecular de ~ 20 kDa e uma alternância de α-galactose 4 ligada e β-galactose 3-ligada, substituído com ésteres de sulfato e éteres de metil, juntamente com a ocorrência de unidades de 3,6-anidro-α-galactoses. No modelo de dieta de 4 semanas, o tratamento com a fração AmII não alteraou o tamanho da placa aterosclerótica e demais características de vulnerabilidade intraplaca, tais como lípido, neutrófilos, macrófagos, metaloprotease de matriz (MMP)-9 e conteúdo de colágeno. No modelo de dieta de 11 semanas, o tratamento com a fração AmII reduziu os conteúdos de macrófago intraplaca e de fator tecidual (FT), em comparação com animais tratados com veículo. O FT intraplaca co-localizou e positivamente correlacionou com áreas ricos em macrófagos. Não foram observadas alterações no tamanho da placa aterosclerótica e nas outras características de vulnerabilidade intraplaca, tais como conteúdos de lipídios, neutrófilos, MMP-9 e do colágeno. Além disso, a expressão de mRNA de MMPs, quimiocinas e marcadores genéticos de polarização de linfócitos Th1/2/reg/17 nos arcos aórticos e nos baços dos camundongos não foi alterada pelo tratamento AmII. In vitro, o tratamento com AmII reduziu de forma dose-dependente a quimiotaxia de macrófagos sem afetar a produção de FT. No geral, o tratamento crônico com AmII foi bem tolerado. Em conclusão, nossos resultados indicam que o tratamento com AmII em camundongos ateroscleróticos reduziu o conteúdo de macrófagos intraplaca, agindo sobre o recrutamento celular, e, concomitantemente, o conteúdo de FT intraplaca de originado potencialmente de macrófagos.
7

Structural characterization and anti-inflammatory activity in asterosclerose model in mice of a sulfada galactan red algae Acanthophora muscoide / CaracterizaÃÃo estrutural e atividade anti-inflamatÃria em modelo de aterosclerose em camundongos de uma galactana sulfatada da alga vermelha Acanthophora muscoides

Ana Luiza Gomes Quinderà 06 March 2015 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Sulfated galactans from red marine algae are polysaccharides with heterogeneous structures that have presented a variety of potentially therapeutic biological effects including anticoagulant, anti-thrombotic and anti-inflammatory, however, their potential activity as anti-inflammatory agent in the treatment of atherosclerosis, a chronic inflammatory disease that culminates with thromboembolic disorders, has not been previously studied. Furthermore, experimental data from animal models and clinical studies support connections between the hemostasis and inflammation in atherogenesis. These interfaces among inflammation and thrombogenesis have been suggested as targets for pharmacological intervention to reduce disease progression. Herein, we determined the chemical structure of a novel sulfated galactan obtained from the marine alga Acanthophora muscoides (fraction AmII) and analysed its effect on a mice model of atherosclerosis in 10-week aged apolipoprotein E deficient (ApoE&#8722;/&#8722;) mice under high-cholesterol diet for additional 4 or 11 weeks. Fraction AmII (10 mg/kg) or Vehicle were subcutaneously injected from week 2 until 4 of the diet or from week 6 until week 11 of the diet. In vitro assays of macrophage chemotaxis were also performed. The structure of the complex sulfated galactan was characterized by solution nuclear magnetic resonance and its molecular mass was determined by gel permeation chromatography and polyacrylamide gel electrophoresis. The sulfated galactan from A. muscoides presents a molecular mass of ~ 20kDa and an alternating 4-linked &#945;-galactose and 3-linked &#946;-galactose, substituted with sulfate esters and methyl ethers along with the occurrence of 3,6-anhydro-&#945;-galactoses. In the 4 weeks diet model, treatment with fraction AmII did not alter the atherosclerotic plaque size, and other intraplaque features of vulnerability (such as lipid, neutrophil, macrophage, MMP-9 and collagen contents). In the 11 weeks diet model, treatment with fraction AmII reduced intraplaque macrophage and tissue factor (TF) content as compared to Vehicle-treated animals. Intraplaque TF co-localized and positively correlated with macrophage rich-areas. No changes on atherosclerotic plaque size, and other intraplaque features of vulnerability, such as lipid, neutrophil, MMP-9 and collagen contents, were observed. Moreover, mRNA expression of MMPs, chemokines and genetic markers of Th1/2/reg/17 lymphocyte polarization within mouse aortic arches and spleens was not affected by AmII treatment. In vitro, treatment with AmII dose-dependently reduced macrophage chemotaxis without affecting TF production. Overall, the chronic AmII treatment was well tolerated. In conclusion, our results indicate that AmII treatment reduced intraplaque macrophage content, by impacting on cell recruitment, and, concomitantly, intraplaque TF content of potential macrophage origin in atherosclerotic mice. / As galactanas sulfatadas obtidas de algas marinhas vermelhas sÃo polissacarÃdeos de estruturas heterogÃneas que tÃm apresentado uma variedade de efeitos biolÃgicos, potencialmente terapÃuticos, incluindo anticoagulante, antitrombÃtico e anti-inflamatÃrio. No entanto, a sua atividade potencial como agente anti-inflamatÃrio para o tratamento de aterosclerose, uma doenÃa inflamatÃria crÃnica que culmina com distÃrbios tromboembÃlicos, nÃo foi previamente estudada. AlÃm disso, dados experimentais de modelos animais e estudos clÃnicos suportam conexÃes entre a hemostasia e inflamaÃÃo na aterogÃnese. Estas interfaces entre inflamaÃÃo e trombogÃnese tÃm sido sugeridas como alvos para intervenÃÃo farmacolÃgica visando reduzir a progressÃo da doenÃa. No presente trabalho, determinou-se a estrutura quÃmica de uma nova galactana sulfatada obtida da alga marinha Acanthophora muscoides (fraÃÃo AmII) e analisou-se seu efeito sobre um modelo de aterosclerose em camundongos deficientes em apolipoproteÃna E (ApoE&#8722;/&#8722;) de 10 semanas submetidos a dieta de alto teor de colesterol durante mais 4 ou 11 semanas. A fraÃÃo AmII (10 mg/kg) ou veÃculo (salina) foram injetados por via subcutÃnea durante a segunda atà a quarta semana de dieta ou a partir da sexta atà a dÃcima primeira semana de dieta. Ensaios in vitro de quimiotaxia de macrÃfagos tambÃm foram realizados. A estrutura da galactana sulfatada complexa foi caracterizada por ressonÃncia magnÃtica nuclear em soluÃÃo e a sua massa molecular foi determinada por cromatografia de permeaÃÃo em gel e eletroforese em gel de poliacrilamida. A fraÃÃo AmII apresentou uma massa molecular de ~ 20 kDa e uma alternÃncia de &#945;-galactose 4 ligada e &#946;-galactose 3-ligada, substituÃdo com Ãsteres de sulfato e Ãteres de metil, juntamente com a ocorrÃncia de unidades de 3,6-anidro-&#945;-galactoses. No modelo de dieta de 4 semanas, o tratamento com a fraÃÃo AmII nÃo alteraou o tamanho da placa aterosclerÃtica e demais caracterÃsticas de vulnerabilidade intraplaca, tais como lÃpido, neutrÃfilos, macrÃfagos, metaloprotease de matriz (MMP)-9 e conteÃdo de colÃgeno. No modelo de dieta de 11 semanas, o tratamento com a fraÃÃo AmII reduziu os conteÃdos de macrÃfago intraplaca e de fator tecidual (FT), em comparaÃÃo com animais tratados com veÃculo. O FT intraplaca co-localizou e positivamente correlacionou com Ãreas ricos em macrÃfagos. NÃo foram observadas alteraÃÃes no tamanho da placa aterosclerÃtica e nas outras caracterÃsticas de vulnerabilidade intraplaca, tais como conteÃdos de lipÃdios, neutrÃfilos, MMP-9 e do colÃgeno. AlÃm disso, a expressÃo de mRNA de MMPs, quimiocinas e marcadores genÃticos de polarizaÃÃo de linfÃcitos Th1/2/reg/17 nos arcos aÃrticos e nos baÃos dos camundongos nÃo foi alterada pelo tratamento AmII. In vitro, o tratamento com AmII reduziu de forma dose-dependente a quimiotaxia de macrÃfagos sem afetar a produÃÃo de FT. No geral, o tratamento crÃnico com AmII foi bem tolerado. Em conclusÃo, nossos resultados indicam que o tratamento com AmII em camundongos aterosclerÃticos reduziu o conteÃdo de macrÃfagos intraplaca, agindo sobre o recrutamento celular, e, concomitantemente, o conteÃdo de FT intraplaca de originado potencialmente de macrÃfagos.

Page generated in 0.0546 seconds