Dissertations / Theses: 'Phaeophycae'

1

Reynes, Lauric. "Connectivité et structure génétiques des populations d'Ericaria Zosteroides (Fucales) et Laminaria rodriguezii (Laminariales) des côtes françaises." Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0205.

Full text

Abstract:

Les forêts d’algues brunes (Phaeophyceae) sont soumises à des combinaisons de pressions d’origine anthropique. Le devenir de ces écosystèmes dépendra de la capacité des populations de ces espèces à évoluer dans cet environnement changeant. A travers ma thèse, j’ai étudié les facteurs susceptibles de contrôler la diversité génétiques des forêts marines en me focalisant sur deux espèces endémiques du bassin méditerranéen, la Fucales Ericaria zosteroides et le kelp des milieux profonds Laminaria rodriguezii. Dans une première partie, je me suis intéressé à la connectivité des populations par une méthode de séquençage partiel du génome (RAD-seq). L’analyse de la structure génétique indique une connectivité réduite, que ce soit pour les populations de E. zosteroides ou L. rodriguezii. En couplant structure génétique et modélisation des courants marins, j’ai étudié la dispersion des propagules en prenant comme cas d’étude, les populations de E. zosteroides en Provence. Les résultats obtenus montrent que la structure génétique est davantage prédite par les courants marins que par l’isolement spatial. Dans une deuxième partie, je me suis intéressé au mode de reproduction de L. rodriguezii, cette espèce étant l’une des rares du genre Laminaria à se reproduire par reproduction végétative et sexuée. Les résultats obtenus confirment l’impact de la clonalité sur la diversité génomique de L. rodriguezii, avec des niveaux variables selon les populations. Outre les questionnements fondamentaux soulevés par ces résultats, l’existence d’une forte structure génétique à courte distance pour des populations éparses, a des implications importantes pour la conservation de ces espèces
Marine forests of brown algae (Phaeophyceae) are impacted by a combination of anthropic pressures. The fate of these ecosystems will depend on the adaptive abilities of populations facing this changing environment. Through my PhD, I studied the factors likely to control the genetic diversity of marine forests by focusing on two endemic species of the mediterranean basin, the Fucoid Ericaria zosteroides and the deep-sea kelp Laminaria rodriguezii. In the first part, I studied the connectivity of populations by a method of reduced representation sequencing of genomes (RAD-seq). The analysis of the genetic structure indicates a reduced connectivity for both E. zosteroides and L. rodriguezii populations. By coupling genetic structure and modeling of marine currents, I studied the role of propagules dispersal, taking as a study case, the populations of E. zosteroides in Provence. The results indicate that the genetic structure is predicted by ocean currents rather than spatial isolation. In the second part, I studied the mode of reproduction of the kelp L. rodriguezii, this species being one of the few of the genus Laminaria to reproduce by vegetative and sexual reproduction. The results obtained indicate an impact of clonality on the genomic diversity of L. rodriguezii, with contrasting levels depending on the populations. In addition to the fundamental questions raised by these results, the existence of a strong genetic structure at short distances for populations divided into habitat patches has important implications for the conservation of these species

APA, Harvard, Vancouver, ISO, and other styles

2

Heesch, Svenja, and n/a. "Endophytic phaeophyceae from New Zealand." University of Otago. Department of Botany, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060901.141241.

Full text

Abstract:

The aims of this study were to find endophytic brown algae in marine macroalgae from New Zealand, isolate them into culture and identify them using morphological as well as molecular markers, to study the prevalence of pigmented endophytes in a representative host-endophyte relationship, and to reveal the ultrastructure of the interface between the obligate parasite Herpodiscus durvillaeae (LINDAUER) SOUTH and its host Durvillaea antarctica (CHAMISSO) HARRIOT. Three species of pigmented endophytic Phaeophyceae were isolated from New Zealand macrophytes. They were distinguished based on morphological characters in culture, in combination with their distribution among different host species and symptoms associated with the infection of hosts. ITS1 nrDNA sequences confirmed the identity of two of the species as Laminariocolax macrocystis (PETERS) PETERS in BURKHARDT & PETERS and Microspongium tenuissimum (HAUCK) PETERS. A new genus and species, Xiphophorocolax aotearoae gen. et sp. ined., is suggested for the third group of endophytic Phaeophyceae. Three genetic varieties of L. macrocystis as well as two varieties each of M. tenuissimum and X. aotearoae were present among the isolates. L. macrocystis and X. aotearoae constitute new records for the marine flora of the New Zealand archipelago, on genus and species level. The red algal endophyte Mikrosyphar pachymeniae LINDAUER previously described from New Zealand is possibly synonymous with Microspongium tenuissimum. The prevalence of infection by Laminariocolax macrocystis was investigated in three populations of Macrocystis pyrifera along the Otago coast. Two of the populations situated inside and at the entrance of Otago Harbour showed high infection rates (average between 95 and 100%), while an offshore population was less infected (average of 35%). The phylogenetic affinities of the parasitic brown alga Herpodiscus durvillaeae, an obligate endophyte of Durvillaea antarctica (Fucales, Phaeophyceae) in New Zealand, were investigated. Analyses combined nuclear encoded ribosomal and plastid encoded RuBisCO genes. Results from parsimony, distance and likelihood methods suggest a placement of this species within the order Sphacelariales. Even though H. durvillaeae shows a reduced morphology, molecular data were supported by two morphological features characteristic for the Sphacelariales: the putative presence of apical cells and the transistory blackening of the cell wall with 'Eau de Javelle'. Ultrastructural sections showed evidence for a symplastic contact between the cells of the parasite H. durvillaeae and its host D. antarctica. Within the host cortex, parasite cells attack the fields of plasmodesmata connecting host cells. In these areas, parasite cells squeeze between the host cells and form secondary plasmodesmata connecting the primary plasmodesmata of the host cells with the cytoplasma of the parasite cell. Moreover, despite being described as lacking pigments, H. durvillaeae possesses a rbcL gene, and its plastids show red autofluorescence in UV light, suggesting the presence of a possibly reduced, but functional photosynthetic apparatus. Vestigial walls between developing spores in the 'secondary unilocular sporangia' of H. durvillaeae confirm the identity of these sporangia as plurilocular gametangia, derived from reduced gametophytes which were entirely transformed into gametangia.

APA, Harvard, Vancouver, ISO, and other styles

3

Givernaud, Thierry. "Recherches sur la Pheophycée Sargassum muticum (Yendo) Fensholt en Basse-Normandie : étude des peuplements, influence de l'environnement sur le développement, régénération in vitro, essais de valorisation." Caen, 1988. http://www.theses.fr/1988CAEN2027.

Full text

Abstract:

Etude des peuplements le long des côtes et estimation de la biomasse exploitable. Etude au laboratoire de l'influence des principaux facteurs du milieu sur la croissance et du développement de l'algue. Morphogénèse des boutures, capacité de régénération. Valorisation par mise au point à une technique d'obtention d'un extrait liquide dont on étudie l'activité sur des plantes horticoles

APA, Harvard, Vancouver, ISO, and other styles

4

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

5

Nehr, Zofia. "Analyse génétique et fonctionnelle du mutant de morphogenèse étoile de l'algue brune ectocarpus siliculosus." Paris 6, 2013. http://www.theses.fr/2013PA066766.

Full text

Abstract:

Les Phaeophyceae ont acquis la multicellularité indépendamment des autres lignées multicellulaires, elles offrent donc la possibilité d’étudier des mécanismes de développement nouveaux et originaux. Ectocarpus siliculosus est l’espèce modèle pour les algues brunes, et les étapes de développement du sporophyte ont été décrites précisément. Pour comprendre leurs bases génétiques et moléculaires, une approche de génétique directe a été adoptée. Le mutant étoile est le premier mutant de morphogenèse décrit de manière exhaustive, sa mutation, simple locus et récessive, découple le tempo et la position de ramification en raison d’un défaut de différenciation cellulaire qui conduit à la sur-ramification. Le rhizoïde du gamétophyte est lui aussi affecté, il rappelle le phénotype du sporophyte. Les deux phénotypes semblent génétiquement liés, et il est probable qu’ils soient dus à la mutation etl. Le locus ETL a été identifié par une approche de clonage positionnel. Le génome du mutant étoile a été séquencé (illumina) ce qui a permis par comparaison avec le génome du sauvage de prédire les mutations candidates dans le locus ETL. La seule mutation non-silencieuse affecte une protéine avec deux domaines fonctionnels : un domaine BAR/IMD et un domaine RhoGAP. Les domaines BAR sont impliqués dans la reconnaissance des membranes et sont capables d’inhiber les domaines RhoGAP qui sont des régulateurs des RhoGTPases. Ce gène s’exprimant dans les cellules apicales du filament de l’algue, il pourrait maintenir la croissance apicale polarisée par l’interaction, aux apex, entre ses deux domaines protéique. Le gène ETL est le premier gène de morphogenèse cloné chez E. Siliculosus, il ouvre d’immenses perspectives en terme de caractérisation fonctionnelle et d’approches « evo-devo »
Multicellularity has occurred independently in Phaeophyceae and in other multicellular lineages. Therefore these organisms offer the opportunity to study novel and alternative developmental processes. Ectocarpus siliculosus is the model species for brown algae and the development of its early sporophyte has been described precisely. To understand the genetic and molecular basis of this development, a forward genetic approach has been carried out. The mutant étoile is the first morphogenetics mutant exhaustively described. Its single locus and recessive mutation, leads to a defect in cell differentiation that decouples branching tempo and position leading to a hyperbranched phenotype. Gametophyte rhizoïde is modifoed as well, it resembles the étoile early sporophyt phenotype. The two phenotypes are genetically linked and thought to be induced by the etl mutation. The ETL locus has been identified by a map-based approach. The illumina sequencing of the mutant genome allowed to propose candidate mutations. The only non-silent mutation affects a protein with two functional domains: a BAR/IMD domain and RhoGAP domain. BAR/IMD domains can recognize lipid membranes and are able to inhibit RhoGAP domains which are regulators for RhoGTPases. As ETL is expressed in the filamentous apical cells, it could maintain tip-growth in the apices through interaction between its two domains. ETL gene is the first morphogenetic gene that has been cloned, and hence it opens hudge perspectives for functional characterization and evo-devo studies

APA, Harvard, Vancouver, ISO, and other styles

6

Rodrigues, Maria Elisa Cairrão Rodrigues. "Fucus spp. (Phaeophyceae, Heterokontophyta) como indicador de contaminação ambiental." Master's thesis, Universidade de Aveiro, 2003. http://hdl.handle.net/10773/21745.

Full text

Abstract:

Mestrado em Toxicologia
O género Fucus apresenta vasta distribuição na zona costeira Ibérica, tendo sido descritas cinco espécies para Espanha e quatro para Portugal (Fucus spiralis L., F. vesiculosus L., F. ceranoides L. e F. serratus L.). Possui enorme importância, tanto ecológica como comercial, essencialmente na produção de produtosnaturais medicinais. As espécies deste género surgem em diversos locais, incluindo os expostos a descargas de efluentes urbanos, industriais e aos lixíviados de terrenos agrícolas, encontrando-se normalmente nas zonas rochosas, onde sofrem zonação notória, que é controlada por complexas interacções fisiológicas e biológicas. O objectivo principal deste trabalho consistiu em efectuar os estudos de base necessários à utilização de espécies do género Fucus como bioindicadores em programas de biomonitorização em zonas costeiras e estuarinas da costa Noroeste de Portugal. Para atingir este objectivo foram desenvolvidos três trabalhos específicos: 1) analisar a variação morfológica de três espécies de Fucus (F. ceranoides, F. spiralis e F. vesiculosus), recolhidos na costa Noroeste Atlântica de Portugal entre o estuário do rio Minho e a Ria de Aveiro durante um ano, e o estabelecimento de correlações com os parâmetros ambientais; 2) avaliar o potencial de bioacumulação de mercúrio das espécies de Fucus [F. ceranoides, F. spiralis (F. spiralis var. platycarpus e F. spiralis var. spiralis) e F. vesiculosus]; 3) desenvolver e validar a metodologia necessária à utilização da actividade de glutationa S-transferase (GST) de Fucus spp. como biomarcador de contaminação ambiental. Através da Análise Canónica de correspondência foi possível perceber que o factor ambiental preponderante na variação dos parâmetros morfométricos parece ser a temperatura, estando este intimamente relacionado com o pH e a salinidade, em todas as espécies analisadas. A quantificação de mercúrio em três partes estruturais (receptáculos, lâmina e base) das espécies de Fucus, permitiu observar que os receptáculos continham menor concentração do que a base e a lâmina. Os valores obtidos para o sedimento apresentaram-se concordantes com os obtidos no material biológico (apesar dos espécimes consistentemente registarem concentrações superiores). Estes resultados sugerem que as espécies e variedades de Fucus estudadas são boas bioindicadores da contaminaçãopor mercúrio, em ecossistemas marinhos e estuarinos. F. ceranoides, F. spiralis var. platycarpus e F. vesiculosus apresentaram os valores mais baixos da actividade da GST nos locais de referência. As estações de amostragem, localizadas em áreas com reconhecida contaminação por hidrocarbonetos aromáticos policíclicos (HAPs), apresentaram valores mais elevados de actividade de GST, sugerindo indução dos mecanismos de destoxificação. Este facto não foi, no entanto, observado em F. spiralis var. spiralis.
The genus Fucusexhibits a wide distribution on the Iberian coast. Five species have been described for Spain and four for Portugal (Fucus spiralis L., F. vesiculosus L., F. ceranoides L. and F. serratus L.). This genus is of enormous importance, both from ecological and commercial (essentially in the production of natural medicinal products) points of view. Fucus spp. exists in several sites, including those receiving urban and industrial effluent discharges and leachates from farmland. The species of the Fucus genus are mainly found in rocky areas, where conspicuous zonation occurs, which is controlled by complex physiological and biological interactions. The main aim of this study was to launch the necessary basis to validate the use of the Fucusspecies as bioindicators in coastal and estuarine environments. To achieve this objective three steps with specific objectives were outlined: 1) analysis of morphologic variation in three species of Fucus (F. ceranoides, F. spiralis and F. vesiculosus), collected during a year, from the Portuguese Northwestern Atlantic coast (between the estuary of Minho river and the Aveiro tidal lagoon), and the establishment of correlations with environmental parameters; 2) evaluation of the potential of Fucus [F. ceranoides, F. spiralis (F. spiralis var. platycarpus and F. spiralis var. spiralis) and F. vesiculosus] to bioacumulate mercury; 3) to develop and validate the necessary methodologies for the application of Fucus spp. glutatione S-transferase as a biomarker of environmental contamination. Canonical correspondence analysis indicates that the dominant factor influencing morphometric parameters is temperature, always in close correlation with pH and salinity. Quantification of mercury in the three structural parts considered (receptacles, stipe and holdfast) showed that the receptacles consistently showed the lowest concentrations throughout the entire sampling campaign. Values obtained for the sediment were always consistent with the ones obtained for specimens, (the latter always presented higher concentrations). This leads to the conclusion that Fucuscan be considered a good bioindicator for mercury contamination in coastal and estuarine environments. As expected, F. ceranoides, F. spiralis var. platycarpus and F. vesiculosus registered the lowest values of GST activity in the reference stations. Sampling stations located in areas were contamination by polycyclic aromatic hydrocarbons (PAHs) is well known, showed higher values of activity for this enzyme, suggesting that detoxification mechanisms were induced.However, a different pattern was observed for F. spiralis var. spiralis.

APA, Harvard, Vancouver, ISO, and other styles

7

Mungioli, Mariana. "Estudos morfológicos e moleculares de algas pardas filamentosas (Phaeophyceae) no litoral sudeste do Brasil." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-25052017-092433/.

Full text

Abstract:

As algas pardas filamentosas (Phaeophyceae) constituem um grupo essencialmente marinho com morfologia extremamente simples. A identificação taxonômica dessas algas é bastante difícil quando empregados apenas caracteres morfológicos devido à grande plasticidade fenotípica que apresentam. No Brasil, nenhum estudo sistemático foi feito com seus representantes empregando-se dados moleculares. Neste contexto, a diversidade de algas pardas filamentosas dos gêneros Acinetospora, Asteronema, Bachelotia, Ectocarpus, Hincksia e Feldmannia foi investigada pela primeira vez no Brasil sob uma abordagem molecular, complementada com dados morfológicos. As coletas abrangeram a região sudeste do Brasil, incluindo a área de ressurgência dos litorais do Rio de Janeiro e Espírito Santo, que abriga quase que a totalidade de táxons de algas pardas filamentosas citadas para o país. Foi utilizado o marcador mitocondrial do tipo DNA Barcode, COI-5P e o marcador plastidial para inferências filogenéticas, o rbcL. Os estudos moleculares e morfológicos permitiram identificar 10 táxons para o litoral sudeste brasileiro: oito da ordem Ectocarpales: Acinetospora filamentosa, \"Feldmannia\" irregulares, \"Feldmannia irregulares\" 1, \"Feldmannia irregulares\" 2, \"Feldmannia\" mitchelliae, \"Hincksia\" conífera e Hincksia sandriana (família Acinetosporaceae) e Ectocarpus fasciculatus (família Ectocarpaceae) e dois da ordem Scytothamnales: \"Asteronema\" breviarticulatum (família Asteronemataceae) e Bachelotia antillarum (família Bachelotiaceae). A família Acinetosporaceae não é monofilética e se dividiu em dois agrupamentos, Acinetosporaceae 1, que incluiu a maioria dos representantes brasileiros e a espécie tipo da família, Acinetospora crinita, e para o qual o nome da família deve ser retido; e Acinetosporaceae 2, que incluiu os autênticos gêneros Feldmannia, Hincksia e Pylaiella com suas respectivas espécies-tipo, Feldmannia lebelli, Hincksia hincksiae e Pylaiella litorallis, respectivamente, e para o qual, uma nova família deverá ser proposta. Hincksia sandriana foi a única espécie estudada que se agrupou no clado do autêntico gênero Hincksia e é citada pela primeira vez para o Brasil, constituindo um caso de introdução recente. Para os demais representantes agrupados em Acinetosporaceae 1, excluindo Acinetospora, um novo gênero para a ciência deverá ser proposto. Os táxons \"H.\" conífera, \"F.\" irregulares, \"F. irregulares\" 1, \"F. irregulares\" 2 e \"F.\" mitchelliae não pertencem aos autênticos gêneros Feldmannia e Hincksia, já que não se agruparam com as respectivas espécies-tipo dos gêneros, e, portanto, devem ser transferidos para o novo gênero. As análises com os dois marcadores moleculares demonstraram que \"F.\" irregulares, \"F. irregulares\" 1 e \"F. irregulares\" 2, previamente citados sob uma única espécie (F. irregulares), representam três entidades taxonômicas independentes. Sequências do COI-5P de F. irregulares da Itália, considerada próxima à localidade tipo (Mar Adriático), confirmaram que parte do material analisado deve ser mantido sob o epíteto irregulares, enquanto duas novas espécies devem ser propostas para a ciência para acomodar \"F. irregulares\" 1 e \"F. irregulares\" 2. As análises moleculares com o COI-5P dividiu \"F.\" mitchelliae em três agrupamentos com alta divergência genética e variabilidade morfológica indicando que \"F.\" mitchelliae forma um complexo. Uma sequência de \"F.\" mitchelliae procedente dos EUA (Carolina do Norte), próxima à localidade tipo (Massachusetts), gerada no presente estudo, confirmou que o material brasileiro deve ser descrito sob o epíteto mitchelliae, porém acomodado sob um novo gênero. Nossos resultados moleculares demonstraram claramente que o gênero Acinetospora não é monofilético. Acinetospora filamentosa é citada pela primeira vez para o Oceano Atlântico e foi revelada por meio de dados moleculares, tanto pelo COI-5P quanto pelo rbcL. A espécie Acinetospora crinita referida previamente para o litoral sudeste do Brasil não foi recoletada neste estudo. Diferenças morfológicas nas estruturas pluriloculares entre as duas espécies e ausência de monosporângios em A. filamentosa, descritos como típico apenas para A. crinita, confirmaram a ocorrência de A. filamentosa para o Atlântico. Nossos resultados com o rbcL revelaram que a família Asteronemataceae não é monofilética. O táxon \"Asteronema\" breviarticulatum se agrupou com Asterocladon lobatum, espécie tipo do gênero, e deve ser alocado na família Asterocladaceae, assim como transferido para o gênero Asterocladon propondo-se uma combinação nova para resolver o posicionamento taxonômico dessa espécie. A alta divergência genética verificada para os marcadores COI-5P e rbcL demonstraram que Bachelotia antillarum é uma espécie críptica. A utilização da ferramenta molecular no estudo de algas pardas filamentosas na região sudeste do Brasil foi fundamental para desvendar a sua diversidade, que comprovadamente estava subestimada, assim como melhor delimitar seus gêneros e espécies e revelar espécies crípticas. Os dados aqui apresentados são pioneiros e constituem uma fonte relevante de informação sobre a taxonomia e sistemática deste grupo de algas pardas. Mais investigações por meio de uma ampla revisão, especialmente da família Acinetosporaceae, uma maior amostragem no litoral brasileiro e inclusão de mais gêneros de algas pardas filamentosas nas análises podem ainda mudar o panorama da classificação desse grupo
Filamentous brown algae (Phaeophyceae) constitute an essentially marine group that display an extremely simple morphology. The taxonomic identification of these algae is very difficult when based only on morphological characters, due to the high incidence of phenotypic plasticity. In Brazil, no systematic study using molecular data has investigated their representatives. In this context, this study aims to investigate the diversity of filamentous brown algae of the genera Acinetospora, Asteronema, Bachelotia, Ectocarpus, Hincksia and Feldmannia for the first time in Brazil, applying the molecular approach coupled with morphological data. The sampling sites covered the southeastern region of Brazil, including the upwelling area of the Rio de Janeiro and Espírito Santo coasts, which include almost all the filaments of brown algae mentioned for the country. The DNA barcode mitochondrial marker, COI-5P, and the plastid marker for phylogenetic inferences, rbcL, were sequenced. The molecular and morphological studies allowed the recognition of 10 taxa on the Brazilian southeastern coast, out of which eight taxa correspond to the order Ectocarpales, and two to the order Scytothamnales. Ectocarpales is represented by the families Acinetosporaceae (Acinetospora filamentosa, \"Feldmannia\" irregularis, \"Feldmannia irregularis\" 1, \"Feldmannia irregularis\" 2, \"Feldmannia\" mitchelliae, \"Hincksia\" conifer and Hincksia sandriana), and Ectocarpaceae (Ectocarpus fasciculatus). The order Scytothamnales, in turn, includes the families Asteronemataceae (\"Asteronema\" breviarticulatum) and Bachelotiaceae (Bachelotia antillarum) The Acinetosporaceae family is non-monophyletic and was divided into two clusters: Acinetosporaceae 1 for which the family name should be retained, included the type species of the family (Acinetospora crinite) and most of the Brazilian representatives; and Acinetosporaceae 2 for which a new family should be proposed, included the genera Feldmannia, Hincksia and Pylaiella represented by their respective type species, Feldmannia lebelli, Hincksia hincksiae and Pylaiella litorallis. Hincksia sandriana was the only species studied that grouped in the clade of the authentic genus Hincksia. Besides, this is the first record of H. sandriana for Brazil, which constitutes a case of recent introduction. For the other representatives of Acinetosporaceae 1, except Acinetospora, a new genus for science should be proposed. The taxa \"H.\" conifer, \"F.\" irregularis, \"F. irregularis\" 1, \"F. irregularis\" 2 and \"F.\" mitchelliae do not belong to the authentic genera Feldmannia and Hincksia, since they did not group with the respective generitypes. Therefore, should be transferred to the new genus. Analyzes applying both molecular markers showed that \"F.\" irregularis, \"F. irregularis\" 1 and \"F. irregularis\" 2, previously cited as a single species (F. irregularis), constitute three independent taxonomic entities. COI-5P sequences of F. irregularis from Italy, close to the type locality (Adriatic Sea), demonstrate that part of the analyzed material should be maintained under the epithet irregularis, whereas two new scientific species should be proposed to accommodate \"F. irregularis \"1 and \" F. irregularis \"2. COI-5P molecular analyzes divided \"F.\" mitchelliae into three clusters with high genetic divergence and morphological variability indicating that \"F.\" mitchelliae corresponds to a species complex. A sequence of \"F. mitchelliae from the United States (North Carolina), near the type locality (Massachusetts), obtained and included in the present study, confirmed that the Brazilian material should be described under the epithet mitchelliae and transferred to a new genus. Our molecular results have clearly demonstrated that the genus Acinetospora is non-monophyletic. Acinetospora filamentosa is for the first time mentioned for the Atlantic Ocean and was revealed by molecular data, both by COI-5P and rbcL. The species Acinetospora crinite recorded on the southeastern coast of Brazil was not collected in this study. Morphological differences in plurilocular structures between two species and absence of monosporangia in A. filamentosa, described as typical only for A. crinite, confirmed the occurrence of A. filamentosa for the Atlantic. Our results with the rbcL revealed that the family Asteronemataceae is non-monophyletic. \"Asteronema\" breviarticulatum was grouped with Asterocladon lobatum, the type species of the genus, and should be transferred to the genus Asterocladon and to the family Asterocladaceae. Consequently, a new combination should be proposed to solve taxonomic placement of this species. The high genetic divergence observed for the COI-5P and rbcL markers demonstrated that Bachelotia antillarum is a cryptic species. The use of the molecular tool in the study of filamentous brown algae in the southeastern region of Brazil was fundamental to uncover their diversity, previously underestimated, as well as to allow a better delimitation of their genera and species. The innovative data presented here constitute a relevant source of information to the taxonomy and systematics of filamentous brown algae. More investigations through a broad review, especially of the Acinetosporaceae family, a wider sampling in the Brazilian coast and the inclusion of more genera of filamentous brown algae in the analyses can still change the classification scenario of this group

APA, Harvard, Vancouver, ISO, and other styles

8

Figueiredo, Camila Silva de. "Contribuição à quimiotaxonomia e ficoquímica de Canistrocarpus cervicornis (Kützing) De Paula & De Clerk (Dictyotaceae) : coletada nos litorais paraibano e fluminense." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/8056.

Full text

Abstract:

Submitted by Clebson Anjos (clebson.leandro54@gmail.com) on 2016-03-29T18:44:13Z No. of bitstreams: 1 arquivototal.pdf: 4614259 bytes, checksum: e4765945b6c16211d7771a473b84ad25 (MD5)
Made available in DSpace on 2016-03-29T18:44:13Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4614259 bytes, checksum: e4765945b6c16211d7771a473b84ad25 (MD5) Previous issue date: 2013-12-05
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Marine biodiversity is presented as a promising source of new substances with high biological potential. Among the many organisms that inhabit the marine environment, we stress the brown algae belonging to the family Dictyotaceae. Genus Canistrocarpus was recently established, and some algae Dictyota formerly were reclassified as Canistrocarpus. This work describes the results of the phycochemical study of Canistrocarpus cervicornis (formerly classified as Dictyota pulchella), and the evaluation of the phycochemical profile of C. cervicornis collected on the coast of Paraíba and the coast of Rio de Janeiro, which contributed to the correct name of Dictyota pulchella as Canistrocarpus cervicornis. Alga samples were collected at Bessa Beach (coordinates 07º04'01 '' S and 34º49'35 '' W), city of João Pessoa (PB) in August 2010 and December 2012. The material was dried at room temperature and extraction was performed with CH2Cl2 : MeOH (2:1). The material was dried at room temperature in fresh air and extraction was performed with CH2Cl2: MeOH (2:1). The extract obtained the first collection was subjected to vacuum filtration on silica gel with solvent hexane, ethyl acetate and methanol in increasing gradient of polarity. The fraction hexane : ethyl acetate (85:15) was subjected to column chromatography yielded one new natural product, the dolastane diterpene 4,7-diacetoxy dichotenone A. The extract resulting from the second collection was divided in two parts. The first part was subjected to column chromatography resulted in the isolation of a known dolastane diterpene, 4-acetoxy-14-hidroxydolast-1(15),7,9-triene. A second aliquot of the extract was acetylated and subjected to column chromatography, which led to the isolation of three diterpenes, one dolastane unpublished in the literature, 4-desoxy-amijidictyol and two known secodolastanes, isolinearol acetate and indicol. Chemical constituents isolated were identified by spectroscopic methods 1H and 13C-1D and 2D NMR, optical rotation and comparison with literature data. This study contributed to the chemotaxonomy of the tribe Dictyoteae, especially C. cervicornis.
A biodiversidade marinha apresenta-se como uma fonte promissora de novas substâncias com grande potencial biológico. Dentre os diversos organismos que habitam o ambiente marinho, merecem destaque as algas pardas pertencentes à família Dictyotaceae e gênero Canistrocarpus. Este gênero foi instituído recentemente, e algumas algas anteriormente denominadas Dictyota foram reclassificadas como Canistrocarpus. O presente trabalho descreve os resultados do estudo ficoquímico de Canistrocarpus cervicornis (anteriormente classificada como Dictyota pulchella), envolvendo a avaliação do perfil ficoquímico de C. cervicornis coletada no litoral da Paraíba e no litoral do Rio de Janeiro. Este estudo contribuiu para a correta denominação da então D. pulchella em C. cervicornis. As amostras da alga foram coletadas na Praia do Bessa (coordenadas 07º04’01’’ S e 34º49’35’’ W) na cidade de João Pessoa (PB), em agosto de 2010 e em dezembro de 2012. A secagem foi realizada a temperatura ambiente, em local arejado e a extração procedida com CH2Cl2:MeOH (2:1). O extrato resultante da primeira coleta foi submetido a uma filtração a vácuo em sílica gel com os solventes hexano, acetato de etila e metanol em gradiente crescente de polaridade. A fração hexano:acetato de etila (85:15) foi submetida a cromatografia em coluna, de onde se obteve um novo produto natural, o diterpeno dolastano 4,7-diacetoxi de dichotenona A. O extrato resultante da segunda coleta foi dividido em duas partes. Uma alíquota foi submetida à cromatografia em coluna, de onde se obteve o diterpeno dolastano conhecido 4-acetoxi-14-hidroxidolasta-1(15),7,9-trieno. A segunda alíquota do extrato foi acetilada e submetida a cromatografias em coluna, o que levou ao isolamento de três diterpenos, sendo um dolastano inédito na literatura, o 4-desoxi-amijidictyol e dois secodolastanos conhecidos, o acetato de isolinearol e o indicol. Os constituintes químicos isolados foram identificados por análises espectroscópicas de RMN 1H e 13C uni e bidimensionais, rotação ótica, e comparação com dados da literatura. Este estudo contribuiu para a quimiotaxonomia da tribo Dictyoteae, em especial de C. cervicornis.

APA, Harvard, Vancouver, ISO, and other styles

9

Motuhi, Sofia-Elena. "Valorisation de substances naturelles marines de Nouvelle-Calédonie d'intérêt en traitement anticancéreux." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1B050.

Full text

Abstract:

Les systèmes de complexes récifaux de l’archipel de la Nouvelle-Calédonie sont explorés depuis près de quarante années pour leur exceptionnelle biodiversité. En effet, de part une position sous-tropicale unique, proche de zones tectoniques actives et du sous-continent Australien, les récifs et lagons néo-calédoniens abritent une importante faune et flore marine relativement protégée des perturbations climatiques. Ces organismes marins se sont avérés être un réservoir considérable de molécules des plus originales et ayant une forte propension à présenter un intérêt thérapeutique notamment dans le cadre du traitement du cancer. L’objectif de cette thèse était de poursuivre cette quête en puisant les substances naturelles dans des macroalgues de Nouvelle-Calédonie. La modulation de la mort cellulaire programmée a notamment été ciblée. Ainsi, les travaux réalisés sur sept espèces de macroalgues rouges (Rhodophyceae) et brunes (Phaeophyceae) collectées dans le lagon Sud de la Nouvelle-Calédonie (arrêté N°197-2016/ARR/DENV) ont permis de révéler leur potentiel dans l’inhibition de la prolifération de cellules cancéreuses en culture. Une espèce de macroalgue rouge a plus particulièrement été travaillée et a conduit à la caractérisation de deux molécules bioactives, dont une n’avait pas été décrite auparavant. L’étude de leur mécanisme d’action cellulaire a révélé que celles-ci pouvaient constituer de nouvelles pistes thérapeutiques intéressantes dans la recherche de nouveaux traitements en chimiothérapie en tant qu’agents antimitotiques inhibiteurs de kinase. Des activités biologiques très intéressantes ont également été révélées pour des fractions issues de deux espèces de macroalgues brunes démontrant une sélectivité significative pour les cellules cancéreuses. Inscrite dans la continuité de multiples bioprospections menées dans les lagons de Nouvelle-Calédonie à la recherche de produits naturels marins d’intérêt thérapeutique, cette thèse de doctorat témoigne du potentiel de plusieurs espèces de Rhodophyceae et Phaeophyceae jusqu’alors très peu explorées chimiquement
Marine zones associated with coral reef systems of the New Caledonia archipelago have been investigated for almost forty years with respect to their plant and invertebrate biodiversity and chemodiversity. In particular, thanks to their unique subtropical position close to tectonically active zones and to the Australian subcontinent, the complex reef systems of New Caledonia’s lagoons are home to a highly diverse marine fauna that is relatively protected from climatic disturbances. This is reflected by the score of novel bioactive molecules that have been discovered and characterized, several of which have been actively investigated for their antineoplastic and antitumoral potential activities. We paid particular attention to macroalgal species that induce programmed cell death, as an approach to detecting original anticancer bioactivities. Seven species of red (Rhodophyceae) and brown (Phaeophyceae) macroalgae collected in the South lagoon of New Caledonia (decree N°197-2016/ARR/DENV) have demonstrated interesting in vitro anticancer activity. In particular, one red macroalgal species led to the characterization of two bioactive natural products, the structure of one of which has not been described to date. Biological tests have shown that these two compounds could be promising candidates as antimitotic kinase inhibitors agents for the development of targeted anticancer chemotherapies. Interesting biological activities have also been revealed from several molecular isolates from two species of brown macroalgae, showing high selectivity towards non-cancerous cells. In the continuing investigations of the therapeutic potential of natural products isolated from New Caledonian marine organisms, this doctoral thesis has highlighted the therapeutic potential of several species of Rhodophyceae and Phaeophyceae which has hitherto been largely unexplored

APA, Harvard, Vancouver, ISO, and other styles

10

Oppliger, Zan Luz Valeria. "Reproduction des grandes algues brunes des côtes Chiliennes et Bretonnes en marge de leur aire de distribution." Paris 6, 2010. http://www.sb-roscoff.fr/images/stories/sbr/Edition-communication/theses/PHD-Thesis-oppliger.pdf.

Full text

Abstract:

Le développement, la reproduction et la survie d’un organisme, dépendent de son environnement physique et/ou écologique. La sélection en faveur de certains traits d’histoire de vie découle donc de la stabilité de l’environnement (i. E. Reproduction sexuée versus asexuée). La stratégie de reproduction d’une espèce est par conséquent susceptible de se modifier en fonction des changements environnementaux, pouvant survenir en limite d’aire de distribution qui se caractérisent par des fluctuations abiotiques plus importantes. Les grandes algues brunes (Phaeophyceae, Laminariales) sont des espèces structurant les communautés benthiques marines. Elles présentent un cycle de reproduction hétéromorphe avec alternance de phase haploïde microscopique (gamétophyte) et de phase diploïde macroscopique (sporophyte). Les connaissances sur la biologie et la distribution géographique de la plupart de ces espèces n’étaient basées jusqu’à présent que sur l’étude des sporophytes. Mes travaux de thèse ont permis de mettre en évidence l’importance de ces gamétophytes dans le maintien des populations, en comparant les modes de reproduction de trois espèces de laminaires. Les résultats suggèrent que le déterminisme du sexe est principalement génétique et que l’effet de la température de l’eau de mer sur la phase microscopique peut expliquer les distributions géographiques de certaines espèces. Par ailleurs, différents stratégies reproductives ont été observées au sein et entre espèces suggérant l’existence de phénomènes d’adaptations locales. En particulier, en limite d’aire de distribution des espèces, nos résultats montrent l’existence de la parthénogenèse géographique.

APA, Harvard, Vancouver, ISO, and other styles

11

Lee, Soon Jeong. "Physiological and biochemical responses to cadmium exposure in Fucus serratus (Phaeophyceae)." Thesis, University of Plymouth, 2009. http://hdl.handle.net/10026.1/499.

Full text

Abstract:

Marine macroalgae can accumulate metals from the surrounding waters. But their responses to metals, especially non-essential metals like cadmium, are not well known and require further investigation. Therefore, the effects of cadmium exposure on the physiology and biochemistry of Fucus serratus collected from metal-contaminated (Restronguet Point) and clean (Bantham Quay) habitats were investigated. Therefore F. serratus demonstrates strong cadmium tolerance to cadmium exposure resulting from the production of antioxidative enzymes, glutathione and phytochelatine.

APA, Harvard, Vancouver, ISO, and other styles

12

Ben, Maiz Naceur. "Flore algale, Rhodophyta, Phaeophyceae, Chlorophyceae, Bryopsidophyceae, de l'étang de Thau, Hérault." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595924r.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Ben, Maïz Naceur. "Flore algale (Rhodophyta, Phaeophyceae, Chlorophyceae, Bryopsidophyceae) de l'Etang de Thau (Hérault)." Aix-Marseille 2, 1986. http://www.theses.fr/1986AIX22057.

Full text

Abstract:

Dans ce travail, 145 taxons d'algues (bangiophyceae, florideophyceae, phaeophyceae, chlorophyceae et bryopsidophyceae) sont mentionnes. La majorite d'entr'eux sont decrites brievement. Plus que la moitie des especes recensees sont nouvelles pour la flore algale de l'etang de thau. Un certain nombre d'especes particulierement interessantes sont decrites plus en detail: chrysymenia wrightii connue du japon et de coree est nouvelle en mediterranee; laminaria japonica, undaria pinnatifida et sargassum muticum, originaires des cotes japonaises, ont ete introduites accidentellement en mediterranee par la voie de l'ostreiculture, dans l'etang de thau; les deux dernieres ont ensuite amorce leur sortie en mer ouverte; griffithsia corallinoides. De l'atlantique, pourrait etre nouvelle en mediterranee; pylaiella littoralis et chorda filum, dont la presence en mediterranee etait douteuse, sphaerotrichia divaricata et desmarestia viridis, toutes de l'atlantique, sont bien representees dans l'etang de thau; laurencia coronopus, endemique de la mer noire, grateloupia doryphora et lomentaria firma. , des cotes italiennes et de l'adriatique, sont nouvelles pour la flore marine francaise; solieria chordalis, alsidium corallinum, elachista stellaris, desmotrichum undulatum, stictyosiphon adriaticus et pseudodictyon inflatum sont des especes rarement signalees en mediterranee occidentale. La physionomie des peuplements a sargassum muticum, espece qui determine une phytocenose particuliere dans l'etang, a ete suivie dans deux stations de substrat dur (meze et balaruc) apparemment differentes par la composition floristique et les variations saisonnieres. L'influence de s. Muticum, qui constitue desormais un element permanent de la flore de l'etang, sur les peuplements indigenes est discutee; le developpement exuberant de cette espece est a l'origine de la reduction du nombre d'especes presentes (occupation de substrat, reduction, parfois extinction, de la lumiere en sous-strate). Les caracteres generaux de la flore algale de l'erang de thau sont examines: affinite froide (dominance de l'element atlantico-boreal) et richesse floristique par rapport aux autres etangs mediterraneens; l'hypothese d'un enrichissement recent de cette flore, en particulier par des especes provenant de l'atlantique ou des cotes japonaises avec l'ostreiculture, a ete discutee

APA, Harvard, Vancouver, ISO, and other styles

14

Othmani, Ahlem. "Médiation chimique entre l’algue brune méditerranéenne Taonia atomaria et la communauté bactérienne associée à sa surface." Thesis, Toulon, 2014. http://www.theses.fr/2014TOUL0001/document.

Full text

Abstract:

Dans le milieu marin, toute surface immergée est rapidement colonisée par des bactéries, puis par d’autres micro-organismes, conduisant à la formation de structures tridimensionnelles complexes appelées biofilms. Cette étape est généralement suivie par l’installation de macro-colonisateurs. Néanmoins, un certain nombre d’organismes marins, tels que les macro-algues, présentent des surfaces peu épiphytées à l’échelle macroscopique. Des algues méditerranéennes (Taonia atomaria et Dictyota spp.) ont été sélectionnées dans le cadre de ces travaux de thèse pour leur capacité à conserver leur surface peu colonisée. Cependant, des observations de leurs surfaces par microscopie ont montré l’existence de biofilms diversifiés à la surface de leurs thalles. Le but de cette thèse est de mieux comprendre les mécanismes de médiation chimique entre ces algues et les bactéries associées à leur surface. La première partie de ce travail a été consacrée à l’étude du rôle de molécules d’origine algale vis-à-vis de l’adhésion de bactéries marines. Pour cela, la composition chimique totale des algues sélectionnées a été analysée conduisant à l’isolement et à la caractérisation structurale de 12 molécules, dont trois se sont révélées être originales. L’activité anti-adhésion de la majorité de ces composés a ensuite été évaluée : le 1-O-octadecenoylglycérol s’est avéré être le produit le plus actif (20 µM < CE50 <55 µM). La deuxième partie a été dédiée plus particulièrement à l’étude du métabolome de surface de T. atomaria dans le but d’évaluer son implication dans les interactions écologiques entre l’algue et les bactéries associées à sa surface. Un protocole d’obtention et d’analyse spécifique des extraits surfaciques a tout d’abord été développé. Ce protocole est basé sur le trempage des thalles dans des solvants organiques et un contrôle de l’intégrité des cellules membranaires des algues y est associé. L’échantillonnage a été effectué mensuellement à Carqueiranne (Nord-ouest de la Méditerranée, France) durant la période allant de février à juillet 2013. Les résultats obtenus montrent qu’un sesquiterpène est exprimé majoritairement à la surface de l’algue. Il a été démontré que ce composé inhibe l’adhésion de souches bactériennes de référence tout en restant inactif vis-à-vis de celles isolées à la surface de l’algue. Une telle spécificité n’a pas été observée ni dans le cas de biocides commerciaux, ni pour les autres métabolites produits par T. atomaria. Dans un second temps, un suivi saisonnier des extraits de surface ainsi que des communautés bactériennes associées a été effectué par métabolomique (LC-MS) et DGGE, respectivement. Des fluctuations saisonnières de ces deux paramètres ont été reportées sans mettre en évidence de corrélation évidente entre eux. La présence de la molécule majeure de surface durant tout le suivi saisonnier a été notée ainsi que sa capacité à diffuser dans l’eau de mer. Enfin, l’étude de l’implication potentielle des bactéries associées à T. atomaria dans le contrôle du biofilm a été entreprise en évaluant l’activité de leurs extraits vis-à-vis de l’adhésion de souches de référence. En conclusion, nous émettons l'hypothèse que T. atomaria pourraient contrôler partiellement le biofilm associé à sa surface en faisant intervenir des métabolites spécifiques
In the marine environment, all submerged surfaces are rapidly colonized by bacteria and other microorganisms, resulting in the formation of complex three-dimensional structures called biofilms. This step could be followed by the attachment of macro-colonizers. Nevertheless, a number of marine organisms, such as macro-algae, appeared to be relatively free of epibionts at a macroscopic scale. In this study, several Mediterranean algae (Taonia atomaria and Dictyota spp.) were selected for their ability to keep their surface free of biofouling. However, microscopic techniques allowed the observation of a diversified biofilm on the surface of their thalli. The purpose of this work was to understand how this alga could interact with its associated bacteria using a chemical ecological approach. The first part of this work deals with studying the anti-adhesion properties of algal molecules against a range of marine bacteria. For this, the whole chemical composition of the two algae was analyzed leading to the isolation and structural characterization of 12 molecules from which three were found to be new. The anti-adhesion activity of some of these compounds was then evaluated: 1-O-octadecenoylglycerol proved to be the most active product (20 µM < EC50 <55 µM). The second part of this study was dedicated to the study of the surface metabolome of T. atomaria in order to assess its involvement in the ecological interactions between the alga and its associated bacteria. A specific extraction protocol was optimized for the surface compounds using a dipping technique in organic solvents associated with the integrity control of algal cell membrane. Sampling was carried out monthly at Carqueiranne (N W Mediterranean Sea, France) between February and July 2013. The results showed the presence of a major molecule in accordance with a sesquiterpenic structure. Anti-adhesion capacity against reference bacterial strains was noticed for this compound, while it remained inactive against strains isolated from the algal surface. This specificity was not observed for commercial biocides and the other molecules purified from crude algal extracts of T. atomaria. Then, changes in surface extracts and associated bacterial surface communities were monitored using metabolomics (LC-MS) and DGGE, respectively. Seasonal fluctuations for the two parameters could be reported without any evident correlation between them. The occurrence of the major molecule throughout the seasonal monitoring was also noticed and its capacity to diffuse in the marine environment was shown. Finally, the study of the potential involvement of the associated bacteria in the biofilm control was conducted by evaluating the anti-adhesion activity of their crude extracts against reference strains. In conclusion, we hypothesize that T. atomaria could control at least partially the biofilm at its surface using specific metabolites

APA, Harvard, Vancouver, ISO, and other styles

15

Dias, Paulo Fernando. "Modulação da vasculogênese, angiogênese e de desenvolvimento tumoral por derivados de Sargassum stenophyllum (Phaeophyceae)." Florianópolis, SC, 2005. http://repositorio.ufsc.br/handle/123456789/101704.

Full text

Abstract:

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-graduação em Farmacologia
Made available in DSpace on 2013-07-15T23:00:01Z (GMT). No. of bitstreams: 1 212760.pdf: 3793665 bytes, checksum: 1d3548c82c1c667fb06eb82add689737 (MD5)
O tratamento in vivo em camundongos com ligantes do receptor periférico benzodiazepínico (PBR) exerceram efeito inibitório na resposta inflamatória em dois modelos de inflamação aguda. No primeiro modelo o efeito antiinflamatório em de pré-tratamento com os ligantes PBR, PK11195 1-(2-chlorophenyl)-N-methyl-N(1-methylpropyl)-3-isoquinoline carboxamide e Ro5-4864 7-chloro-5-(4-Chlorophenyl)-1,3-dihydro-1-methyl-2-H-1,4-benzodiazepin-2, mostraram que a formação do edema em resposta a carragenina (300 mg/pata) foi inibida por PK11195 e Ro5-4864, em diferentes intervalos de tempo. O estudo do tempo resposta mostrou que a melhor resposta com ambos ligantes foi ótima em animais injetados no tempo de 24h, por esta razão este tempo de pré-tratamento foi escolhido para estudo da dose resposta. A formação do edema de pata em resposta a carragenina (300 mg/pata) foi reduzida por PK11195 e Ro5-4864 em diferentes doses (0,00001-10mg/kg, i.p.) produzindo uma inibição dose dependente na formação do edema de pata em camundongos induzida pela carragenina. PK11195 e Ro5-4864 (0.1 mg/kg, i.p.) quando administrado 24 h antes da indução do edema, inibiram de forma significativa o edema de pata de camundongos induzido por vários mediadores inflamatórios. No segundo modelo o pré-tratamento com os ligantes (0.1 mg/kg, i.p.), 24 h antes da indução da pleurisia induzida pela carragenina, mostrou uma significante inibição no recrutamento das células totais e diferenciais, principalmente a custas de neutrófilos, inibindo também a liberação de Interleucina-13 (IL-13) e Interleucina-6 (IL-6) no líquido pleural

APA, Harvard, Vancouver, ISO, and other styles

16

RODRIGUES, Samara. "Estudo taxonômico da ordem Dictyotales (Phaeophyceae - Heterokontophyta) no litoral do estado de Alagoas - Brasil." Universidade Federal Rural de Pernambuco, 2015. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/4584.

Full text

Abstract:

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-06-02T14:10:37Z No. of bitstreams: 1 Samara Rodrigues.pdf: 2007129 bytes, checksum: 302f3c0c854772f4f4281af71ee55629 (MD5)
Made available in DSpace on 2016-06-02T14:10:37Z (GMT). No. of bitstreams: 1 Samara Rodrigues.pdf: 2007129 bytes, checksum: 302f3c0c854772f4f4281af71ee55629 (MD5) Previous issue date: 2015-02-09
The Dictyotales order (Phaeophyceae) is distributed in temperate and tropical flora. In Brazil, they occur from Maranhão to Rio Grande do Sul, besides Atol das Rocas and the archipelagos of Fernando de Noronha and Trindade. In the Northeast, this order is the most significant in numbers of species within the Phaeophyceae. Given its importance, this study aimed to make the taxonomic and floristic study of the order on the coast of the state of Alagoas, which has a great phycological diversity. Four sampling stations were selected along the coast. Samples were collected seasonally in the dry and rainy season, during low tides, in the intertidal zones using a spatula and/or in free dives. The collected material was fixed in 4% formalin and transported to the Federal Rural University of Pernambuco (UFRPE). The taxonomic identification was based on morphological and anatomical characters and was confirmed by specialized bibliographies. The taxonomic position was organized according to Wynne (2011). In the studied area the Dictyotales were represented by 20 taxa, distributed among the genera Canistrocarpus (three), Dictyopteris (five), Dictyota (six), Lobophora (one), Padina (four) and Spatoglossum (one). Five species are being cited as the first occurrence to Alagoas´ coast (C. crispatus (J.V. Lamour.) De Paula & De Clerck, D. jamaicensis W.R. Taylor, D. polypodioides (A.P.D.E. Candolle) J.V.Lamouroux, D. pinnatifida Kützing and P. antillarum (Kützing) Piccone). The study provides identification key to the species level and for each species identified a description, comments and ecological illustration. Among the 20 species of Dictyotales found, only Canistrocarpus cervicornis, C. crispastus, Dictyopteris delicatula, Dictyota jamaicensis, Padina antillarum and Spatoglossum schroederi occurred in the four sampling stations. The greatest richness was found in rocky substratum with occurrence of all species. Of the 20 taxa, 19 were common in both the seasons. Regarding the frequency of occurrence, in the dry and rainy season two taxa occurred as very common C. cervicornis and Dictyopteris delicatula. The similarity analysis (ANOSIM) showed significant differences between the sampling sites. The genera that had some problems in their identification were mostly Canistrocarpus and Dictyota, but with the observation of morphological and anatomical characters, conflicts were resolved. Chemical and biomolecular analyzes should be undertaken to better define the taxonomic limits of conflicting species of these genera.
A ordem Dictyotales (Phaeophyceae) está distribuída na flora tropical e temperada. No Brasil, os seus representantes ocorrem desde o Maranhão até o Rio Grande do Sul, além do Atol das Rocas e Arquipélagos Fernando de Noronha e Trindade. No Nordeste, essa ordem é a mais expressiva em números de representantes dentro das Phaeophyceae. Diante dessa importância, este trabalho teve como objetivo realizar o estudo taxonômico e florístico da referida ordem no litoral do estado de Alagoas. Foram eleitas quatro estações de coleta ao longo do litoral. As coletas foram realizadas sazonalmente, no período seco (novembro e dezembro de 2013 e janeiro de 2014) e chuvoso (maio a julho de 2014), durante as marés baixas, nas zonas entremarés, com auxílio de espátula e/ou através de mergulhos livres. O material coletado foi fixado em formol a 4% e transportado à Universidade Federal Rural de Pernambuco (UFRPE). A identificação taxonômica baseou-se nos caracteres morfo-anatômicos e foi confirmada através de bibliografia especializada. A posição taxonômica foi organizada de acordo com Wynne (2011). Na área estudada as Dictyotales foram representadas por 20 táxons específicos, distribuídos entre os gêneros Canistrocarpus (três), Dictyopteris (cinco), Dictyota (seis), Lobophora (um), Padina (quatro) e Spatoglossum (um). Cinco espécies estão sendo citadas como primeira ocorrência para o litoral alagoano (C. crispatus (J.V. Lamour.) De Paula & De Clerck, Dictyopteris jamaicensis W.R.Taylor, D. polypodioides (A.P.De Candolle) J.V.Lamouroux, Dictyota pinnatifida Kützing e P. antillarum (Kützing) Piccone). O estudo fornece chave de identificação em nível específico e para cada espécie identificada, uma descrição, comentários ecológicos e ilustração. Dentre as 20 espécies encontradas, Canistrocarpus cervicornis, C. crispastus, Dictyopteris delicatula, Dictyota jamaicensis, Padina antillarum e Spatoglossum schroederi ocorreram nas quatro estações de coleta. A maior riqueza foi encontrada no substrato consolidado rochoso, com a ocorrência de todas as espécies. Dos 20 táxons encontrados, 19 foram comuns em ambos os períodos estacionais. Com relação à frequência de ocorrência, dois táxons ocorreram como muito frequentes C. cervicornis e Dictyopteris delicatula. A análise de similaridade (ANOSIM) mostrou diferenças significativas entre os locais de amostragem. Os gêneros que apresentaram alguma problemática em sua identificação foram principalmente Canistrocarpus e Dictyota, mas com a observação de caracteres morfológicos e anatômicos os conflitos foram resolvidos. Análises químicas e biomoleculares devem ser realizadas para melhor definir os limites taxonômicos das espécies conflitantes desses gêneros.

APA, Harvard, Vancouver, ISO, and other styles

17

Mackenzie, Ian M. "Genetic and morphological variation in Macrocystis C. Agardh (Laminariales, Phaeophyceae) off the North American coast." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24196.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Schmitz, Caroline. "Compostos fotoprotetores que absorvem radiação UV-VIS em algas pardas (Phaeophyceae) da Costa do Brasil." reponame:Repositório Institucional da UFSC, 2017. https://repositorio.ufsc.br/xmlui/handle/123456789/181609.

Full text

Abstract:

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia de Fungos, Algas e Plantas, Florianópolis, 2017.
Made available in DSpace on 2017-12-05T03:15:12Z (GMT). No. of bitstreams: 1 348748.pdf: 1269425 bytes, checksum: 3c1e8a307d9c4eed6b63ab24341ed589 (MD5) Previous issue date: 2017
Os efeitos da radiação solar nos processos químicos e biológicos nos ambientes marinhos dependem principalmente da intensidade e do comprimento de onda. Os ambientes costeiros sempre estiveram sujeitos às altas radiações, porém a redução da camada de ozônio e o aumento do fluxo de UVR incidente são prejudiciais para organismos marinhos, principalmente aos fotossintetizantes. Para se protegerem desta variação, macroalgas adaptaram mecanismos de fotoproteção que são relacionados com a síntese de compostos que absorvem radiação UV/PAR atenuando estes efeitos deletérios. Atualmente, a busca por compostos bioativos naturais provenientes do ambiente marinho vem crescendo. Algas pardas são reconhecidas por sintetizar metabólitos secundários com potencial biotecnológico. O Brasil é rico em recursos aquáticos e apresenta uma costa com uma alta biodiversidade de espécies. Isso acarreta em um elevado potencial de espécies com compostos bioativos. O presente estudo teve como enfoque a prospecção de compostos que absorvem radiação UV/PAR com potencial biotecnológico, atrelando sua variação aos fatores abióticos. As algas foram coletadas na costa brasileira em vinte e três locais, provenientes de três regiões do Brasil. Todas as amostras foram condicionadas em sílica-gel. Foi obtido um extrato em metanol:clorofórmio dessas espécies e feita uma varredura de sua capacidade de absorver radiação UV-VIS, correlacionando esse aspecto aos fatores abióticos. As espécies de Phaeophyceae apresentaram um perfil característico do grupo com sete regiões principais de absorbância. As substâncias com maior interesse no grupo são os florotaninos e cumarinas absorvendo na região UV e carotenoides e clorofilaxiiabsorvendo na região PAR. Foi identificada a região 1 (Nordeste) com os maiores índices de compostos que absorvem radiação UV/PAR. Nesta avaliação, observou-se que temperatura, nebulosidade e nitrato estão diretamente correlacionadas aos compostos que absorvem a radiação UV/PAR. Como uma continuação do trabalho, recomenda-se que as substâncias fotoprotetoras, como fenólicos ou carotenoides, sejam extraídas e separadas / purificadas para maior detalhamento das moléculas e suas potencialidades.
Abstract : The effects of solar radiation on chemical and biological processes in marine environments depend mainly on intensities and wavelengths. Coastal environments have always been subject to high radiation, but the loss of the ozone layer and the increased flux of incident UVR are detrimental to marine organisms, especially photosynthesizers. To protect them from this variation, macroalgae adapted photoprotection mechanismsincluding the synthesis of UV / PAR absorbing compounds, attenuating these deleterious effects. Currently, the search for natural bioactive compounds from the marine environment has been growing. Brown algae are recognized for synthesizing secondary metabolites with biotechnological potential. Brazil is rich in aquatic resources and presents a coast with a high biodiversity of species. This leads to a high potential of finding species with bioactive compounds. The present study focused on the prospection of compounds that absorb UV/PAR radiation with biotechnological potential, linking its variation to abiotic factors. The algae were collected on the Brazilian coast in twenty-three sites, from three regions of Brazil. The samples were conditioned on silica gel. An extract was obtained in methanol: chloroform from these species and a scan of its capacity to absorb UV-VIS radiation, correlating this aspect with the abiotic factors. The silica gel method is not the most recommended for analysis of the metabolomics, and the percentage of degradation could compromise the significance of analyzes. The species of Phaeophyceae presented a characteristic profile of the group with seven main regions of absorbance. The substances of greatest interest in the group are the phlorotannins and coumarins absorbing in the UV region and carotenoids and chlorophyll absorbingxivin the PAR region. Region 1 (Northeast) was identified with the highest indexes of UV / PAR absorbing compounds. In this evaluation, it was observed that temperature, cloudiness and nitrate are directly correlated to these compounds variability. As a continuation of the work, it is recommended that photoprotective substances, such as phenolics or carotenoids, could be extracted and separated / purified for further detailing of the molecules and their potentialities.

APA, Harvard, Vancouver, ISO, and other styles

19

Butler, Declan M. "Isolation and culture of protoplasts and tissues of Laminaria spp. (Phaeophyta)." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237096.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

21

Turner, David John. "Effects of sedimentation on the structure of a phaeophycean dominated macroalgal community." Connect to this title online, 2004. http://hdl.handle.net/2440/37702.

Full text

Abstract:

Macroalgae are abundant on shallow temperate reef environments, often forming complex communities that comprise several strata. In southern Australia, these assemblages are dominated by large canopy forming taxa from the Orders Laminariales and Fucales. The presence of subtidal fucoid macroalgae differentiates these communities from that elsewhere, and emphasises the need for local studies rather than relying on generalisations made elsewhere. Like most natural systems, temperate reefs are often threatened by human activity with degradation reported from many locations in close proximity to urban settlements. The work presented in this thesis involves an examination of the temporal and spatial variability in the structure of macroalgal communities from reefs along the Adelaide (South Australia) metropolitan coast. The work looked specifically at the effects of a dispersed sediment plume, resulting from the 1997 beach sand-replenishment dredging program, on shallow sub-tidal reef systems. An examination of the structure of canopy forming phaeophycean macroalgae in Gulf St Vincent (South Australia), noted large amounts of both spatial and temporal heterogeneity. Notwithstanding, this variation was not random, but demonstrated considerable structure that could be linked to a number of important underlying processes. In particular, macroalgal assemblages appeared as a mosaic of patches, each of which comprised a high-density state clearly dominated by a single genus (Cystophora, Sargassum, or Ecklonia), or alternatively a lower density mixed assemblage (Variable Low Abundance, VLA). Macroalgal community structure appeared to be driven by biotic interactions at small scales (metres), such that patches comprised of different species of algae in high density states rarely abutted one another. Instead, VLA assemblages frequently formed a buffer being situated between these mono generic patches. In terms of successional processes, the high-density states appeared to be relatively stable whereas the VLA state, at least in some systems, was transitory. This finding was supported by the absence of intermediary high- density states (e.g. a mix of Cystophora and Ecklonia) implying that state changes must occur via the VLA state following some form of disturbance. Larger scale patterns appeared to be driven by environmental variation, with factors such as wave exposure influencing habitat suitability for individual species and thereby affecting community composition. These phenomena were examined in terms of life history strategies that tend to promote stability, and which are common in late successional taxa. The importance of properties enhancing stability and the role of disturbance was investigated experimentally using a dispersed sediment plume, which entirely engulfed two reefs, as a pulse impact. This disturbance was of particular relevance given that degradation of macroalgal communities in close proximity to the City of Adelaide has been, at least in part, attributed to the effects of elevated levels of sediment. Follow up surveys revealed that the sedimentation from the plume had primarily affected newly recruiting individuals, with few juveniles surviving to one year of age. Over the following few years, the effect of this recruitment failure cascaded into the adult stand. In broader terms, unfavourable climatic conditions prior to the start of the study, including a particularly severe El Nino event, had a widespread effect on local assemblages, causing high levels of both adult and juvenile mortality. As such, at the commencement of the study, macroalgal communities across the study area were in the process of recovery. This was observed at control sites over the duration of the study. In contrast, recruitment failure at the sediment-affected sites retarded the recovery process, exacerbating the problems associated with prior unfavourable climatic events and leaving them in a degraded state. This study demonstrated that macroalgal assemblages are equipped (under natural conditions) to handle 'normal' environmental fluctuations (such as inter-annual variability). However, the additional stress associated with certain anthropogenic impacts has the potential to push them over the limit, causing degradation. The loss of canopy macroalgae reduces the structural complexity of the system, leading to a concomitant reduction in their ability to recover. As such, these findings are of particular relevance to those charged with the responsibility for managing near-shore marine environments. The plume was created accidentally during a dredging operation for beach sand replenishment of Adelaide's eroding shoreline.
Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2004.

APA, Harvard, Vancouver, ISO, and other styles

22

Turner, David J. "Effects of sedimentation on the structure of a phaeophycean dominated macroalgal community /." Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09pht944.pdf.

Full text

Abstract:

Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2005?
"July 2004" Includes bibliographical references (leaves 150-172). Also available electronically.

APA, Harvard, Vancouver, ISO, and other styles

23

Mattio, Lydiane. "Taxonomie du genre Sargassum (Fucales, Phaeophyceae) en Nouvelle-Calédonie et dans le Pacifique Sud : approches morphologique et moléculaire." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2008. http://tel.archives-ouvertes.fr/tel-00589775.

Full text

Abstract:

Sargassum C. Agardh est un genre de macrophyte marine appartenant à la classe des Phaeophyceae. Ce genre est réparti mondialement et reconnu comme un des plus diversifiés de l'ordre des Fucales. Il est particulièrement bien représenté dans le Pacifique tropical et intertropical où il forme de grandes algueraies dont l'importance écologique et l'intérêt économique sont reconnus. Néanmoins, avec près d'un millier de taxons décrits depuis 200 ans, et une classification complexe et ancienne, identifier une espèce de Sargassum est une tâche difficile. La diversité du genre Sargassum des îles du Pacifique Sud a été analysée ici dans son contexte biogéographique Indopacifique. L'étude a été réalisée grâce à une méthode combinée utilisant des analyses morphologiques et ADN sur des collections récentes provenant de plusieurs régions du bassin Pacifique. La classification ainsi que la valeur taxonomique des caractères morphologiques traditionnellement utilisés ont été remis en question. Plus de 52 nouvelles synonymies ont été proposées ainsi que des révisions significatives de la classification traditionnelle du sous-genre Sargassum.

APA, Harvard, Vancouver, ISO, and other styles

24

Piarulli, Stefania. "Divergence patterns in Fucus seaweeds (Phaeophyceae) in the northern Baltic Sea and in the Tjongspollen area." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9544/.

Full text

Abstract:

To be able to interpret patterns of biodiversity it is important to understand the processes by which new species evolve and how closely related species remain reproductively isolated and ecologically differentiated. Divergence and differentiation can vary during speciation and it can be seen in different stages. Groups of closely related taxa constitute important case studies to understand species and new biodiversity formation. However, it is important to assess the divergence among them at different organismal levels and from an integrative perspective. For this purpose, this study used the brown seaweeds genus Fucus as a model to study speciation, as they constitute a good opportunity to study divergence at different stages. We investigated the divergence patterns in Fucus species from two marginal areas (northern Baltic Sea and the Tjongspollen area), based on phenetic, phylogenetic and biological taxonomical criteria that are respectively characterised by algal morphology, allele frequencies of five microsatellite loci and levels of secondary polyphenolic compounds called phlorotannins. The results from this study showed divergence at morphological and genetic levels to certain extent but complete lack of divergence at biochemical level (i.e. constitutive phlorotannin production) in the Baltic Sea or Norway. Morphological divergence was clearly evident in Tjongspollen (Norway) among putative taxa as they were identified in the field and this divergence corresponds with their neutral genetic divergence. In the Baltic, there are some distinguishable patterns in the morphology of the swedish and finnish individuals according to locality to certain extent but not among putative taxa within localities. Likewise, these morphological patterns have genetic correspondence among localities but not within each locality. At the biochemical level, measured by the phlorotannin contents there were neither evidence of divergence in Norway or the Baltic Sea nor any discernable aggregation pattern among or within localities. Our study have contributed with further understanding of the Baltic Sea Fucus system and its intriguingly rapid and recent divergence as well as of the Tjongspollen area systems where formally undescribed individuals have been observed for the first time; in fact they appear largely differentiated and they may well warrant a new species status. In current times, climate change threatens, peripheral ecosystems, biodiversity, and increased knowledge of processes generating and maintaining biodiversity in those ecosystems seem particularly important and needed.

APA, Harvard, Vancouver, ISO, and other styles

25

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/.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

26

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.

Full text

Abstract:

Orientadora: Maria Eugênia Duarte Noseda
Co-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

APA, Harvard, Vancouver, ISO, and other styles

27

Farrell, Paul. "A study of the recently introduced macroalga Undaria pinnatifida (Harvey) Suringar (Phaeophyceae Laminariales) in the British Isles." Thesis, University of Portsmouth, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396386.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Ang, Put Ong. "Natural dynamics and matrix models of a fucus distichus (phaeophyceae, fucales) population in Vancouver, British Columbia, Canada." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30796.

Full text

Abstract:

Patterns of reproduction, micro-recruitment, macro-recruitment, age- and size-dependent reproduction, growth and mortality in a population of the brown alga Fucus distichus in Vancouver, British Columbia, Canada, were examined from May 1985 to November 1987. Using log linear and association analyses, age and size are both found to be significant, but size more so than age, as descriptors of the demographic parameters. Reproductive plants were found throughout the sampling period, but peaked in fall and winter of each year. Estimated monthly egg production, calculated by the observed number of eggs in clusters extruded from the receptacle, is independent of plant size. Two types of recruits were monitored. Microrecruits (< 1 month-old of microscopic size) are germlings developed from fertilized eggs. Their numbers were assessed using settling blocks. Macrorecruits are detectable by the unaided eye and are plants appearing in the permanent quadrats for the first time. The recruitment pattern of microrecruits is significantly correlated with reproductive phenology and patterns of potential and estimated monthly egg production. However, peaks in micro-recruitment are not always followed by peaks in macro-recruitment. This apparent discrepancy is probably due to a differential survivorship of microrecruits over time or to the possible existence of a "germling bank". Patterns of survival and emergence of macrorecruits may be independent of those of microrecruits or may be unrelated to the prevailing reproductive phenology. This population of Fucus distichus showed seasonal variations in plant mean length and growth rates. Mean length was greater in winter (4.2-5.3 cm) and lower in summers of 1986 and 1987 (2.7 - 4.3 cm). Absolute growth rates showed a significantly opposite trend, being higher in spring and summer (0.24 - 1.17 cm/month) and lower in fall to winter (-0.5 - 0.4 cm/month). The relationship between reproduction, growth and mortality was also evaluated in terms of the cost of reproduction. There is no clear indication of cost of reproduction with respect to the longevity or mortality of fertile vs. non-fertile plants. Fertile plants, especially those > 17 cm in length, tend to exhibit negative or zero growth much more often than non-fertile plants, suggesting the cost of reproduction may be manifested in the form of reduced growth rather than in greater mortality or shorter longevity of the fertile plants. The failure to detect cost of reproduction may be due to the modular character of the plants, where cost occurs at the level of the modules (branches) rather than at the level of the whole plant. The effect of density on mortality and growth among recruits in this population was also monitored. In the first 2 months of development, germlings growing at high density experienced a lower mortality than those growing at lower densities. At later stages (> 2 months), the effect of density on mortality was reversed. Plant growth rate was generally not related to density but was related to plant length. The dynamics of the population was further evaluated with a 9 x 9 matrix model based on recruit stages and plant size. From the elasticity analysis, the survival and transition of the plants among size classes was found to be the most important parameter and contributed at least 50% to the population growth rate (lambda). Fucus does not grow by vegetative propagation, the population can only experience positive growth in the presence of recruitment. The current population size structure is unstable and is very different from the projected stable distribution. Overall, the population is on the decline. However, it is likely that the population may recover by occasional pulses of a large number of recruits, an example of which was observed in 1986.
Science, Faculty of
Botany, Department of
Graduate

APA, Harvard, Vancouver, ISO, and other styles

29

Billot, Claire. "Structuration genetique des populations de laminaria digitata (phaeophycees) en manche : utilisation de marqueurs hypervariables." Paris, Institut national d'agronomie de Paris Grignon, 1999. http://www.theses.fr/1999INAP0003.

Full text

Abstract:

Laminaria digitata, classe des pheophycees, ordre des laminariales, est une macroalgue brune commune en manche et en atlantique. Elle forme des populations importantes le long des cotes rocheuses, en mode semi-battu ou battu, au niveau de l'etage infra-littoral. Les laminariales se distinguent par un cycle de reproduction haplodiplophasique nettement heteromorphe (sporophytes macroscopiques ; gametophytes microscopiques). Le sporophyte, thalle d'environ 1,5 m de long, est recolte (environ 60. 000 t/an, principalement en manche) pour sa forte teneur en alginate. Ces deux caracteristiques (cycle de vie, recolte), ainsi que la continuite de ses peuplements, font de cette espece un bon modele d'etude de la diversite genetique en milieu marin. Des marqueurs microsatellites, rares chez cette espece, ont ete identifies chez l. Digitata afin d'etudier son regime de reproduction ainsi que la structuration de ses populations en manche. Les individus presentent un apparentement a l'echelle du metre, provenant de la faible dispersion des gametes males. L'effectif efficace des peuplements continus est estime a 16 000 individus, soit environ un km de long. Il semble que l'allofecondation y soit la regle, signe de la dispersion des spores. La differenciation entre populations se fait selon le modele d'isolement par la distance et reflete assez bien les courants en manche, ainsi que les effets des substrats sur la structure du peuplement. Cette etude est la premiere de cette ampleur (nombre d'individus et nombre de locus) chez des especes a peuplement continu et en particulier, chez les algues. Elle a permis de mettre en evidence deux systemes de dispersion : les gametes d'une part et d'autre part les spores ou l'arrachage de fragments de thalles fertiles. De plus, elle a permis de detecter des isolements liees aux courants dans un milieu considere comme a priori homogene.

APA, Harvard, Vancouver, ISO, and other styles

30

Lydon, Anniken. "Identification of Saccharina groenlandica (Phaeophyceae) around the Svalbard Archipelago: DNA barcoding using cytochrome c oxidase subunit 1 (COI)." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1368.

Full text

Abstract:

In the Arctic, brown algae (kelps) and seaweeds are ecologically important: providing habitat, protection, and nutrients for invertebrate and vertebrate species living in nearshore environments. Migrations of biota between the North Pacific and North Atlantic Oceans have occurred periodically during Earth’s history leading to colonization of the Arctic Ocean. Around 3.5 Mya the “Great Trans-Arctic Biotic Interchange” occurred and the Laminariales order of kelp, thought to be of North Pacific origin, underwent a massive radiation and speciation event around the Arctic Ocean. Phylogenetic analysis performed on “Laminaria-like” specimens collected from six sampling locations around the Svalbard Archipelago identified both the presence of Saccharina groenlandica and Laminaria digitata. This research represents new records for the presence of S. groenlandica around the Svalbard Archipelago. S. groenlandica and L. digitata exhibit phenotypic similarities such that these two species can be difficult to tell apart in the field. In this study we have shown that the COI gene region can be used for DNA barcoding and can provide species level resolution between these two cryptic species. Prior to this study and Lund (2014), a number of biodiversity studies conducted around the Svalbard Archipelago identified the presence of L. digitata in a number of locations around the archipelago, however S. groenlandica was not identified in any of these prior studies. Phylogenetic analysis conducted here showed that all Svalbard specimens of S. groenlandica had identical COI sequences and up to 0.30% sequence diversity with S. groenlandica specimens from other parts of the Arctic Ocean. Further analysis is needed to understand the abundance of this newly recorded species around the archipelago and to investigate both the timing of arrival and mechanisms of colonization.

APA, Harvard, Vancouver, ISO, and other styles

31

Pavani, Lilian. "Anfipodes gamarideos associados a bancos de Sargassum (Phaeophyceae, Fucales) em ambientes sujeitos a contaminação por hidrocarbonetos de petroleo." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316363.

Full text

Abstract:

Orientador: Fosca Pedini Pereira Leite
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-14T00:36:25Z (GMT). No. of bitstreams: 1 Pavani_Lilian_M.pdf: 1390022 bytes, checksum: 43df8a085a06d86b5eadaf092c0fbf14 (MD5) Previous issue date: 2009
Resumo: Na região do Canal de São Sebastião, onde opera o maior terminal petrolífero do Brasil, há extensos bancos de algas pardas do gênero Sargassum e anfípodes associados, mas também existem hidrocarbonetos alifáticos e aromáticos de petróleo na água e no sedimento. Sabese que os anfípodes são eficientes bioindicadores de qualidade ambiental, assim como as algas são importantes bioacumuladores. Avaliou-se a presença de hidrocarbonetos em Sargassum e buscou-se relacionar suas concentrações com distâncias crescentes a partir do terminal, tanto ao norte quanto ao sul da Ilha de São Sebastião. Essas concentrações e distâncias também foram utilizadas para verificar a estruturação das comunidades de anfípodes do fital de Sargassum. Essa avaliação foi feita para anfípodes, abordando-se a composição de grupos tróficos e de espécies. Não foi constatada relação entre as distâncias e concentrações de hidrocarbonetos presentes nas algas e na estruturação das comunidades de anfípodes em nenhuma das abordagens. No entanto, notou-se correspondência entre elas, o que indica que a identificação em famílias para o estabelecimento de grupos tróficos pode ser eficiente numa avaliação ambiental mais rápida. Também se obteve importante informação em relação à fauna de anfípodes do litoral do Estado de São Paulo, uma vez que ainda não havia estudos na Ilha de São Sebastião e a fauna de ilhas do estado ainda é pouco conhecida
Abstract: In the São Sebastião Channel region, where operates the greatest Brazilian petroliferous terminal, there are extensive banks of the brown seaweed Sargassum with many associated amphipods, but also polyciclic aromatic hydrocarbons and aliphatic hydrocarbons, which are present both in sedment and water. The amphipods are known to be efficient bioindicators of environmental quality, as well as the seaweed are important bioacumulators. The presence of hydrocarbons in Sargassum and its relationship with increasing distances from the terminal, both north and south of the São Sebastião Island, was evaluated. These concentrations and distances were also used to verify the structure of amphipod communities associated to Sargassum . This evaluation was made for amphipods identified in trofic groups and in species. There was no significant relationship between distances from the terminal and concentrations of hydrocarbons in the seaweed or the estructure of the amphipod communities. However, correspondence between the aproachs (trofic groups and species) was noticed, which indicates that the identification in families for the establishment of trofic groups can be efficient in a faster ambient evaluation. Also, important information related to amphipods of the São Paulo State coast was achieved, as far as the fauna of São Sebastião Island was first studied and the islands fauna of the State are still little known
Mestrado
Ecologia
Mestre em Ecologia

APA, Harvard, Vancouver, ISO, and other styles

32

Silberfeld, Thomas. "Contributions des phylogénies moléculaires à la systématique et à la compréhension de l'évolution des algues brunes (Ochrophyta, Phaeophyceae)." Paris, Muséum national d'histoire naturelle, 2010. http://www.theses.fr/2010MNHN0023.

Full text

Abstract:

La systématique des algues brunes (Ochrophyta, Phaeophyceae) est longtemps restée nébuleuse. L'objectif de cette thèse était d'explorer la systématique des Phaeophyceae à des échelles variées au moyen de phylogénies moléculaires. Un jeu de données de plus de 10 000 pb a été analysé afin de réévaluer les relations inter-ordinales. Des temps de divergence moyens ont en outre été estimés sous un modèle d'horloge moléculaire relâchée et calibrée par le registre fossile. Ces estimations suggèrent que l'histoire des Phaeophyceae a été marquée par un épisode d'accélération des cladogénèses pendant env. 30 Ma au cours du Crétacé inférieur. Nos analyses nous ont également permis de clarifier la systématique de plusieurs taxons à pyrénoïdes (ex. Chordariopsis, Spongonema), et de proposer un nouvel ordre des Asterocladonales. Enfin, un riche échantillonnage pour le genre Padina (Dictyotales) nous a permis une investigation des processus de spéciation et de la biogéographie chez ce genre
Systematics of brown algae (Ochrophyta, Phaeophyceae) has long remained a significant challenge. The goal of my PhD was to explore systematics within Phaeophyceae at various scales through molecular phylogenies. First, a 10,000+ nt data set was analysed to reassess interordinal relationships. Moreover, mean divergence times were estimated under a fossil-calibrated bayesian relaxed molecular clock model. Our estimates suggest that the evolutionary history of brown algae was marked by an increase in the cladogenetic rhythm for ca 30 Ma during Lower Cretaceous. Multi-locus data sets have also allowed us to clarify the systematic position of several poorly studied pyrenoid-bearing taxa (e. G. Chordariopsis, Spongonema), and noticeably resulted in the proposal of a new order Asterocladonales. Finally, the availability of a rich sampling for the genus Padina (Dictyotales) has allowed us to shed light upon speciation processes and biogeography in the genus

APA, Harvard, Vancouver, ISO, and other styles

33

Hernández, Oyarzún Juan Eduardo. "Tolerancia a estrés térmico en plántulas con heterogeneidad genética (quiméricas) y unitarias en la macroalga parda Lessonia spicata (Phaeophyceae)." Tesis, Universidad de Chile, 2018. http://repositorio.uchile.cl/handle/2250/151854.

Full text

Abstract:

título de Biólogo con mención en Medio Ambiente
El quimerismo ocurre cuando dos individuos genéticamente distintos y conspecíficos se fusionan o coalescen generando una única entidad genéticamente heterogénea conocida como quimera. Este aumento en la variabilidad genética intraorganismo supondría un aumento en la variabilidad fenotípica del mismo, lo que conferiría a estas entidades una mayor tolerancia ante cambios ambientales en comparación a individuos genéticamente homogéneos o no quiméricos, posiblemente debido a efectos sinérgicos entre las distintas líneas celulares. El beneficio de ser quimera ha sido estudiado en distintos grupos de algas, particularmente en especies de algas rojas (Gracilaria y Mazzaella), las cuales muestran una correlación positiva entre coalescencia y tolerancia al estrés. A pesar de ello, en macroalgas pardas los estudios han sido mayoritariamente descriptivos, evidenciado los procesos de formación de entidades quiméricas, así como la frecuencia del quimerismo en poblaciones naturales de Lessonia spicata. Sin embargo, se desconoce aún si en esta especie los organismos con quimerismo muestran mayor tolerancia al estrés que aquellos genéticamente homogéneos y si existe un efecto en la adecuación biológica de la quimera de acuerdo al número de individuos fusionados así como el nivel de parentesco de los individuos que se fusionan para formar la quimera (e.g. fusión entre hermanos, medios hermanos, vecinos, poblaciones distintas). Basado en lo anterior, el objetivo de este estudio fue evaluar la tolerancia a estrés por temperatura de plántulas quiméricas y unitarias de L. spicata cultivadas en condiciones contrastantes de temperatura, distinto número de individuos fusionados y nivel de parentesco. Para ello, primero se desarrolló un protocolo para la generación masiva de plántulas con variabilidad genética intraorganismo de L. spicata en laboratorio. Segundo, se evaluó la tolerancia al estrés en términos de la tasa de crecimiento en condiciones contrastantes de temperatura (12±2°C vs 18±2°C) de plántulas quiméricas con distinto número de individuos fusionados versus unitarias. Tercero, se evaluó el efecto del parentesco sobre la quimera y el estrés térmico, comparando crecimiento entre unitarias, quimeras conformadas por cepas locales y quimeras conformadas por cepas de distintas poblaciones. Los resultados indicaron que plántulas quiméricas provenientes de la fusión de 5 esporofitos poseen una mayor tasa de crecimiento que las plántulas unitarias en condiciones normales de temperatura (12°C). Mientras que a estrés 10 térmico (18ªC) plántulas quiméricas también poseen una mayor tasa de crecimiento, pero la significancia de la respuesta depende de la densidad y parentesco de las entidades que forman la quimera. En términos de parentesco, los resultados sugieren que las quimeras provenientes de la fusión de esporofitos de plantas no emparentadas poseen una tasa de crecimiento mayor que quimeras formadas con medios hermanos. A la luz de estos resultados es posible concluir que el quimerismo en la macroalga parda Lessonia spicata le conferiría una ventaja a dichos organismos frente a los continuos cambios ambientales. Este hecho adquiere relevancia si se sabe que la especie está constantemente expuesta a cambios de la temperatura producto del Niño, así como el aumento de la temperatura del océano causado por cambio climático.
Chimerism occurs when two genetically distinct and conspecific individuals fuse or coalesce, generating a single entity genetically heterogeneous known as chimera. This condition increase the intraorganismal genetic variability, that could increase in the phenotypic variability and provide higher tolerance to environmental changes compared to genetically homogeneous or non-chimeric individuals. These can be produced due to synergistic effects between the genetically different cell lines that coexist into the chimera. The benefit of chimeric condition has been studied in different groups of macroalgae, particularly in the red species (Gracilaria and Mazzaella). They show a positive correlation between coalescence and stress tolerance. Despite of this, in the brown macroalgae the studies have been poorly described, most of them are descriptive, evidencing the formation processes of chimeric entities, as well as the frequency of chimerism in natural Lessonia spicata populations. However, it is still unknown whether the chimerism in Lessonia species shows greater stress tolerance than those genetically homogeneous. As well as whether there the fitness is affected by to the number of individuals fused, and/or the level of kinship among the individuals that composed the chimera (e.g. fusion between siblings, half siblings, neighbors, different populations). In this context, the main objective of this study was evaluate the thermal stress tolerance of chimeric and unitary organism in the brown macroalgae L. spicata, which were cultivated under contrasting temperature conditions, different number of fused individuals and level of kinship. To this, firstly in this study generated a protocol for massive generation of plantlets with intraorganismal genetic variability of L. spicata in laboratory. Secondly, the stress tolerance was evaluated in terms of specific growth rate under contrasting temperature conditions (12 ± 2 °C vs 18 ± 2 °C) of chimeric plantlets with different numbers of individuals fused versus unitary ones. Thirdly, the effect of kinship on the chimera and thermal stress was evaluated by comparing growth rate between unitary individuals versus chimeras formed by local strains, and from different populations. The results indicate that chimeric plantlets resulting from the fusion of 5 sporophytes have a higher growth rate than the unitary plantlets under normal conditions (12°C). While under thermal stress (18°C) the chimeras have the higher growth rate. However, the significant differences depended on the density and kinship of the entities that made up the chimera and the culture temperature. In terms of 12 kinship, the results suggest that chimeras resulting from the fusion of sporophytes of unrelated plants have a higher growth rate than chimeras formed by half-sib brothers. Follow these results, it is possible to conclude that chimerism in the brown macroalga Lessonia spicata would confer an advantage to these organisms in face to continuous environmental changes. This fact acquires relevance if it is known that this species is constantly exposed to temperature changes produced by ENSO events, as well as the increase in the ocean temperature caused by climate change.

APA, Harvard, Vancouver, ISO, and other styles

34

Rios, Matos Dora Luisa. "Producción de citoquinas de respuesta inmune celular en ratones inmunizados y tratados con fucoidan de Lessonia trabeculata (Phaeophyceae, laminariales)." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2020. https://hdl.handle.net/20.500.12672/11736.

Full text

Abstract:

El fucoidan es un polisacárido extraído de algas pardas y ha sido ampliamente estudiado por sus propiedades anticoagulantes, antivirales, antiinflamatorias, antioxidantes, antitumorales, antiangiogénicas e inmunomoduladoras, que varían de acuerdo a la especie. Lessonia trabeculata es un alga parda del litoral peruano que se emplea en la industria alimentaria; sin embargo, tiene otros usos potenciales que deben ser investigados. El desarrollo de nuevos productos con actividad biológica a partir de estas algas requiere de evaluaciones in vitro e in vivo. El objetivo fue evaluar la producción de citoquinas de respuesta inmune celular: TNF-α, TNF-β, IFN-γ e IL-2, la producción de especies reactivas de oxígeno (ERO) y óxido nítrico (NO) en ratones inmunizados con glóbulos rojos de carnero (GRC) y tratados con diferentes concentraciones del extracto liofilizado rico en fucoidan de Lessonia trabeculata, empleándose como control fucoidan de Fucus vesiculosus. Los ratones fueron tratados durante 14 días por vía oral, para evaluar la respuesta inmune primaria (RIP), y durante 28 días, para la respuesta inmune secundaria (RIS). Las ERO se evaluaron mediante el ensayo de reducción de nitroazul de tetrazolio, y el NO por la reacción de Griess. La expresión génica y la presencia de citoquinas séricas se determinaron mediante PCR convencional y ELISA de tipo sándwich, respectivamente. Los resultados obtenidos demuestran que el extracto liofilizado rico en fucoidan de Lessonia trabeculata no influye en la producción de ERO ni NO, incrementa la expresión de TNF-α y la concentración en suero de TNF-α, IFN-γ e IL-2 e inhibe la expresión de TNF-β en RIP, promueve la expresión de TNF-β e IL-2, inhibe la expresión de TNF-α y reduce la concentración en suero de IL-2 en RIS. Se concluye que el extracto liofilizado rico en fucoidan de Lessonia trabeculata estimula la inmunidad celular en la respuesta primaria y secundaria, sin embargo, es necesario complementar estos resultados con posteriores investigaciones.
Perú. Ministerio de la Producción. Programa Nacional de Innovación para la Competitividad y Productividad (Innóvate Perú)
Universidad Nacional Mayor de San Marcos (Lima). Vicerrectorado de Investigación y Posgrado
Tesis

APA, Harvard, Vancouver, ISO, and other styles

35

Le, Lann Klervi. "Étude de la biodiversité des Sargassaceae (Fucales, Phaeophyceae) en milieux tempéré et tropical : écologie, chimiotaxonomie et source de composés bioactifs." Brest, 2009. https://tel.archives-ouvertes.fr/tel-00976868.

Full text

Abstract:

Quatre genres de Sargassaceac présentant de forte biomasse en Bretagne et/ou dans le Pacifique Sud ont été choisi comme modèles de cette étude. Les objectifs étant i) de mieux comprendre l’écologie chimique des Sargassaceae en milieu tempéré et en milieu tropical, ii) de rechercher des chimiomarqueurs spécifiques à certaines espèces et iii) de rechercher de molécules potentiellement bioactives. Ainsi, un travail pluridisciplinaire a été entrepris avec l’étude de l’écologie chimique des Sargassaceae, en Bretagne d’une part, via l’étude des variations spatio-temporelles de certains composés de défenses synthétisés par Sargassum muticum, Bjfurcaria bifurcata et Cystoseira baccata associé à un suivi écologique de ces espèces et dans le Pacifique Sud d’autre part, via l’étude de ces mêmes composés de défenses au sein de Turbinaria sp. Et Sargassum sp provenant de différents sites. Parallèlement, deux études de chimiotaxonomie ont été menées. D’une part sur le genre Turbinaria afin d’identifier un ou des chimiomarqueur(s) permettant de discriminer T. Ornata et de T. Conoides. Et d’autre part sur B. Bifurcata afin de mieux comprendre la répartition géographique des types chimiques existants au sein de cette espèce. Puis, pour répondre au troisième objectif de cette thèse, trois activités biologiques ont été recherchées en priorité au sein des espèces étudiées: la cytotoxicité, l’activité anti-inflammatoire et la neurotoxicité. Les résultats de cette étude ont permis i) de mettre en évidence l’impact des conditions environnementales sur les variables biologiques et écologiques étudiées chez ces espèces en milieu tempéré comme en milieu tropical; ii) d’identifier l’acide turbinarique comme étant un chimiomarqueur de l’espèce T. Conoides et de mettre en évidence l’existence d’éeotypes chez B. Bifurcata; iii) de rapporter l’activité anti-phospholipase A2 d’acides gras issus d’algues du Pacifique Sud et l’activité antiradicalaire et antioxydante de l’éléganolone isolée chez B. Bifurcata
Four Sargassaceae genus presenting high biomass in Brittany and/or in the South Pacificwere chosen as models of this study. The aims of this works were i) to understand the chemical ecology of Sargassaceae in temperate and tropical environment, ii) to characterize specific chemomarkers from certain species and iii) to identify potential bioactive molecules. Then, a pluridisciplinary work was carry out with the study of the chemical ecology of Sargassaceae, in Brittany on one hand, with the study of the spatio-temporal variations of certain defense compounds of Sargassum muticum, Bifurcaria bifurcata and Cystoseira baccata associated with an ecological survey of these species and in the South Pacific on the other hand, with the study of these same defense compounds within Turbinaria sp. And Sargassun sp from various sites. At the same time, two chemotaxonomical studies were led. On the Turbinaria genera to identify one or several chemomarker(s) allowing discriminating T. Ornata and T. Conoides. And on the other hand, on B. Bifurcata to understand the geographical distribution of the existing chemical types within this species. Then, to answer the third objective of this work, three biological activities were looked for first and foremost within the studied species: cytotoxicity, anti-inflammatory activity and neurotoxicity. The results allowed i) to highlight the impact of the environmental conditions on the biological and ecological variables studied to these species in temperate and tropical enviromnents; ii) to identify the acid turbinaric as a chemomarker of T. Conoides and to highlight the existence of ecotypes from B. Bifurcata; iii) to report the anti-phospholipase A2 activity of fatty acids stemming from tropical seaweeds and the antiradical and antioxidant activities of eleganolone isolated from B. Bifurcata

APA, Harvard, Vancouver, ISO, and other styles

36

Le, Lann Klervi. "Etude de la biodiversité des Sargassaceae (Fucales, Phaeophyceae) en milieux tempéré et tropical : écologie, chimiotaxonomie et source de composés bioactifs." Phd thesis, Université de Bretagne occidentale - Brest, 2009. http://tel.archives-ouvertes.fr/tel-00976868.

Full text

Abstract:

Quatre genres de Sargassaceae présentant de forte biomasse en Bretagne et/ou dans le Pacifique Sud ont été choisi comme modèles de cette étude. Les objectifs étant i) de mieux comprendre l'écologie chimique des Sargassaceae en milieu tempéré et en milieu tropical, ii) de rechercher des chimiomarqueurs spécifiques à certaines espèces et iii) de rechercher de molécules potentiellement bioactives. Ainsi, un travail pluridisciplinaire a été entrepris avec l'étude de l'écologie chimique des Sargassaceae, en Bretagne d'une part, via l'étude des variations spatio-temporelles de certains composés de défenses synthétisés par Sargassum muticum, Bifurcaria bifurcata et Cystoseira baccata associé à un suivi écologique de ces espèces et dans le Pacifique Sud d'autre part, via l'étude de ces mêmes composés de défenses au sein de Turbinaria sp. et Sargassum sp provenant de différents sites. Parallèlement, deux études de chimiotaxonomie ont été menées. D'une part sur le genre Turbinaria afin d'identifier un ou des chimiomarqueur(s) permettant de discriminer T. ornata et de T. conoides. Et d'autre part sur B. bifurcata afin de mieux comprendre la répartition géographique des types chimiques existants au sein de cette espèce. Puis, pour répondre au troisième objectif de cette thèse, trois activités biologiques ont été recherchées en priorité au sein des espèces étudiées: la cytotoxicité, l'activité anti-inflammatoire et la neurotoxicité. Les résultats de cette étude ont permis i) de mettre en évidence l'impact des conditions environnementales sur les variables biologiques et écologiques étudiées chez ces espèces en milieu tempéré comme en milieu tropical ; ii) d'identifier l'acide turbinarique comme étant un chimiomarqueur de l'espèce T. conoides et de mettre en évidence l'existence d'écotypes chez B. bifurcata ; iii) de rapporter l'activité anti-phospholipase A2 d'acides gras issus d'algues du Pacifique Sud et l'activité antiradicalaire et antioxydante de l'éléganolone isolée chez B. bifurcata.

APA, Harvard, Vancouver, ISO, and other styles

37

Dixon, Nicholas Michael. "The ecology of Ectocarpus fasciculatus (Ectocarpales, Phaeophyceae) on a shore in southern England and the incidence of an infecting virus." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288925.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Lovazzano, Bravo Carlos Daniel. "Activación de peroxirredoxinas en respuesta al estrés oxidativo causado por cobre en las macroalgas Scytosiphon gracilis y Lessonia nigrescens (phaeophyceae)." Tesis, Universidad de Chile, 2011. http://www.repositorio.uchile.cl/handle/2250/112082.

Full text

Abstract:

Tesis para optar al grado académico de Magíster en Bioquímica, área de especialización Bioquímica Ambiental y Memoria para optar al Título Profesional de Bioquímico
El cobre es un micronutriente esencial, pero a altas concentraciones puede inducir la síntesis de especies reactivas de oxígeno (ROS), causando una condición de estrés oxidativo. En sitios costeros contaminados por cobre, prevalecen sólo algunas especies de macroalgas, como Scytosiphon lomentaria y Ulva compressa, las que presentan mecanismos eficientes de tolerancia al metal. Contrariamente, la macroalga parda Lessonia nigrescens, ecológicamente importante en la zona intermareal, se encuentra ausente en sitios contaminados por cobre y presenta mecanismos de tolerancia al metal insuficientes. Recientemente, en Scytosiphon gracilis, macroalga parda que presenta mecanismos de tolerancia similares a los descritos en S. lomentaria, se identificaron proteínas involucradas en la tolerancia al estrés por cobre, entre las que se encuentran las peroxirredoxinas (PRXs), enzimas capaces de reducir peróxido de hidrógeno, alquilhidroperóxidos y peroxinitritos, escasamente estudiadas en macroalgas. Estas enzimas reaccionan a bajas concentraciones de peróxidos en comparación a otras enzimas como catalasa y son susceptibles a inactivación a elevadas concentraciones de peróxidos. En el presente trabajo, se estudió la activación PRXs en respuesta al estrés oxidativo generado por cobre en las algas pardas S. gracilis y L. nigrescens, cultivadas en presencia de concentraciones crecientes del metal (5 a 100 μg Cu L-1, más un control sin adición de cobre) durante 96 h. Se evaluó marcadores de daño oxidativo, como la generación de lipoperóxidos y la pérdida de eficiencia máxima del fotosistema II (Fv/Fm). Adicionalmente, se realizó estudios de inmunofluorescencia para detectar PRXs en ambas especies. Los resultados indicaron que las PRXs mostraron afinidad tanto por peróxido de hidrógeno como por ter-butil hidroperóxido como sustratos y se observó un aumento de la actividad usando DTT como agente reductor a partir de 5 μg Cu L-1. Los niveles de actividad PRX en S. gracilis fueron superiores a los de L. nigrescens en todas las concentraciones del metal evaluadas e incluso en individuos no expuestos al metal (i.e. actividad basal). Los valores máximos de actividad PRX se registraron en 40 μg Cu L-1 en S. gracilis y en 10 μg Cu L-1 en L. nigrescens. En ambas especies se detectó un aumento de la actividad PRX acoplada a tiorredoxina, pero la actividad PRX acoplada a glutarredoxina sólo aumentó en S. gracilis. Se observó inhibición de la actividad PRX a partir de 20 μg Cu L-1 en L. nigrescens y en S. gracilis a partir de 100 μg Cu L-1. Este fenómeno coincidió en ambas especies con un aumento de lipoperóxidos, lo que sugiere que las PRXs controlarían los niveles de lipoperóxidos generados por estrés oxidativo. Respecto a la medición de eficiencia fotosintética, si bien se observó un efecto del cobre sobre los fotosistemas en ambas especies, resultó ser un parámetro menos sensible que los lipoperóxidos y no hubo diferencias a nivel global entre las especies. Análisis de inmunofluorescencia mostraron que en L. nigrescens no variaron los niveles proteicos de PRX en individuos tratados con 10 y 100 μg Cu L-1 respecto a su control y que en S. gracilis aumentan los niveles proteicos de PRX en individuos tratados con 40 μg Cu L-1 y disminuye en 300 μg Cu L-1, coincidiendo con los resultados de actividad enzimática. Los resultados sugieren que las PRXs participan en la tolerancia al estrés por cobre, actuando como una barrera antioxidante, siendo más eficientes en S. gracilis que en L. nigrescens. La actividad de las PRXs en S. gracilis ayuda a explicar funcionalmente la capacidad de esta especie de tolerar ambientes contaminados con altos niveles de cobre, mediante la reducción de peróxidos y posiblemente mediante el control de vías de señalización redox, que regulan la adaptación de esta especie a sitios contaminados por cobre. En el caso de L. nigrescens, la pérdida de actividad de las PRXs frente a bajas concentraciones de cobre ayudaría a explicar el grave daño celular que se genera en esta especie y, a nivel ecológico, el impedimento que esto le genera para colonizar ambientes contaminados por el metal.
Copper is an essential micronutrient, but at high concentrations can induce the synthesis of reactive oxygen species (ROS), generating a condition of oxidative stress. In coastal copper-impacted sites, prevail only a few species of macroalgae, such as Scytosiphon lomentaria and Ulva compressa, which have efficient metal tolerance mechanisms. Conversely, the brown seaweed Lessonia nigrescens, environmentally important in the intertidal zone, is absent from copper-impacted sites and presents insufficient metal tolerance mechanisms. Recently, in Scytosiphon gracilis, brown seaweed that presents similar tolerance mechanisms to those described in S. lomentaria, proteins involved in tolerance to copper-induced stress were identified, among them, peroxiredoxins (PRXs). These enzymes are capable to reduce hydrogen peroxide, alkylhydroperoxides and peroxynitrites, and have been poorly studied in macroalgae. These enzymes react at low concentrations of peroxides in comparison to other enzymes such as catalase and are susceptible to inactivation at high concentrations of peroxides. In this work, the PRX activation was studied in response to copper-induced oxidative stress in brown algae S. gracilis and L. nigrescens cultured with increasing concentrations of the metal (5 to 100 μg Cu L-1, and a control without copper addition) for 96 hours. Oxidative damage markers, such as the generation of lipoperoxides and loss of photosystem II efficiency (Fv/Fm) were evaluated. Additionally, an immunofluorescence study was carried out in order to detect PRXs in both species. The results indicated that the PRXs showed affinity for both hydrogen peroxide and ter-butyl hydroperoxide as substrates, and an increase in activity was observed using DTT as a reducing agent from 5 μg Cu L- 1. PRX activity in S. gracilis was superior to L. nigrescens in all the copper concentrations assessed and even in individuals not exposed to the metal (i.e. basal activity). The maximum values of PRX activity occurred at 40 μg Cu L-1 in S. gracilis and at 10 μg Cu L- 1 in L. nigrescens. An increase of PRX activity coupled to thioredoxin was detected in both species, but PRX activity coupled to glutaredoxin only increased in S. gracilis. It was observed loss of PRX activity from 20 μg Cu L- 1 in L. nigrescens and S. gracilis from 100 μg Cu L-1. This phenomenon coincided in both species with an increase of lipoperoxides, which suggests that the PRXs would control the levels of oxidative stress-generated lipoperoxides. Respect to the measurement of photosytem II efficiency, while an effect of copper on the photosystems in both species was observed, this marker was less sensitive than the lipoperoxides and there was no overall differences between the species. Immunofluorescence analysis showed that in L. nigrescens treated with 10 and 100 μg Cu L-1 PRX levels did not suffer any change respect to the control. In S. gracilis there was an increase of PRX levels in individuals treated with 40 μg Cu L- 1 and a decrease at 300 μg Cu L-1, coinciding with the results of enzymatic activity. The results suggest that the PRXs are involved in tolerance to copper-induced stress, acting as an antioxidant barrier, being more efficient in S. gracilis than in L. nigrescens. The PRX activity in S. gracilis helps to explain the ability of this species to tolerate copper-enriched environments, through the reduction of peroxides and possibly through the control of redox signaling pathways that regulate the adaptation of this species to polluted sites. In the case of L. nigrescens, the loss of activity of the PRXs at low copper concentrations would help to explain the severe cellular damages that occur in this species, and ecologically, the impediment of L. nigrescens to colonize copper-enriched environments.
Conicyt; Fondecyt

APA, Harvard, Vancouver, ISO, and other styles

39

Mubaiwa, Byron Tawanda. "The quantification of fucoxanthin from selected South African marine brown algae (Phaeophyta) using HPLC-UV/Vis." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017879.

Full text

Abstract:

Marine brown algae (seaweeds) are a rich source of fucoxanthin, a xanthophyll carotenoid that is naturally, an accessory pigment in the process of photosynthesis of sea vegetation such as Sargassum incisifolium. Fucoxanthin has been exploited by nutraceutical companies for its anti-obesity effects that has resulted in an increase of seaweed slimming preparations such as FucoThin™. The field is getting widespread consumer attention as interest in fucoxanthin has also transcended to its widespread biological potential which include cytotoxicity, anti-diabetic, anti-oxidant, anti-inflammatory and anti-plasmodium effects. We therefore wanted to identify a reliable source(s) of fucoxanthin from diverse samples of South African marine brown algae in order to explore our medicinal chemistry interests around the cytotoxicity and anti-malarial potential of fucoxanthin. A known source, Sargassum incisifolium, was used to isolate (maceration in CH₂Cl₂/MeOH at 35 °C followed by a hexane/EtOAc step gradient silica column of the crude extract and reversed phase semi-prep HPLC) and characterize (1D and 2D NMR) fucoxanthin (reference standard) in order to develop an analytical method for its determination in selected diverse brown algae commonly found in South Africa. The HPLC [Column: Phenomenex® Synergi™ (250 x 3.0 mm i.d); Mobile phase: ACN/H2O (95:5)] method developed for this analysis was validated according the guidelines set by the International Conference on Harmonization (ICH). Fifteen species were then assessed for fucoxanthin content (μg/g of dried weight) using the developed method. Stability studies on fucoxanthin were also carried out to assess photo- and pH degradation of fucoxanthin. Zonaria subarticulata (KOS130226-18) from Kenton-On-Sea beach and Sargassum incisifolium (PA130427-1) from Port Alfred beach were found to be the highest producers of fucoxanthin with 0.50 mg/g and 0.45 mg/g dried weight respectively. Fucoxanthin was found to be both photo-labile and sensitive to both acidic and basic pH environments. However, the pigment was more photostable in pure as opposed to extract form and also showed to be more stable at pH 10.0. Our findings show that Z. subarticulata and S. incisifolium could be reliable sources of fucoxanthin and can be considered as the algae to use in optimized extraction procedures in further studies. Also, when working with fucoxanthin, it is important to protect it from light. Any consideration of taking fucoxanthin preparation orally (as a nutraceutical) should consider protecting the active from the harsh conditions of the gastrointestinal tract. Any upscale production of fucoxanthin from seaweed should consider variations such as geographical, seasonal, lifecycle stage, etc. of identified algae as these may be important factors in obtaining effective concentrations of fucoxanthin.

APA, Harvard, Vancouver, ISO, and other styles

40

Bernard, Miriam. "Molecular interactions between the kelp saccharina latissima and algal endophytes." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS105.

Full text

Abstract:

Des algues brunes endophytes envahissent les tissus des laminariales, avec des effets potentiellement négatifs sur leur hôte. Des études moléculaires ont permis d'identifier deux genres, Laminarionema et Laminariocolax, dominant la diversité de ces endophytes. Une étude épidémiologique par qPCR a montré une forte prévalence de l'endophyte Laminarionema elsbetiae chez Saccharina latissima, avec des variations saisonnières et locales. En laboratoire, la présence de L. elsbetiae induit des réponses physiologiques différentes chez S. latissima, son hôte principal, et chez Laminaria digitata, un hôte occasionnel. Une approche transcriptomique a révélé des réponses moléculaires différentes chez les deux hôtes et l'endophyte, en lien avec les mécanismes de reconnaissance et de défense des deux partenaires. Ces spécificités du dialogue moléculaire lors des premières étapes de l'interaction pourraient expliquer la variabilité des profils d'infection observés dans les populations naturelles
Endophytic brown algae invade stipes and fronds of kelps with potential negative effects for their hosts. The molecular diversity of kelp endophytes was investigated and a majority of the isolated endophytes belonged to the genera Laminarionema and Laminariocolax. Using a qPCR approach, a high prevalence of the endophyte Laminarionema elsbetiae was detected in natural Saccharina latissima populations, but with seasonal and geographical variations. Co-cultivation experiments showed different physiological responses of the main host, S. latissima, and an occasional host, Laminaria digitata, to L. elsbetiae. A transcriptomic approach revealed important differences between the molecular responses of the two kelps, related to the recognition of the endophyte and subsequent defence reactions. These specific differences in the molecular cross-talk during the early steps of the interaction could explain the variability of natural infection patterns in kelp species

APA, Harvard, Vancouver, ISO, and other styles

41

Heinrich, Sandra [Verfasser], Klaus [Akademischer Betreuer] Valentin, Christian [Akademischer Betreuer] Wiencke, and Kai [Akademischer Betreuer] Bischof. "Effects of multiple abiotic stresses on gene expression in Saccharina latissima (Phaeophyceae) / Sandra Heinrich. Gutachter: Christian Wiencke ; Kai Bischof. Betreuer: Klaus Valentin." Bremen : Staats- und Universitätsbibliothek Bremen, 2012. http://d-nb.info/1071993380/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Aknin, Maurice. "Etude des acides gras, stérols et métabolites secondaires de quelques chlorophycées, rhodophycées et phaeophycées de la côte sénégalaise." Aix-Marseille 3, 1991. http://www.theses.fr/1991AIX30055.

Full text

Abstract:

L'objet de cette these concerne l'etude des compositions en acides gras et en sterols de quelques chlorophycees, rhodophycees et phaeophycees de la cote senegalaise et l'identification de plusieurs metabolites isoles a partir de ces algues. Les compositions en acides gras et en sterols ont ete determinees par des analyses chromatographiques et spectroscopiques. Pour les chlorophycees, nous avons montre que chaque ordre et meme chaque genre peut etre caracterise par des acides gras et des sterols particuliers. L'etude des rhodophycees a permis de mettre en evidence dans la classe des solieriacees, et ce pour la premiere fois dans les organismes vivants, des acides gras cyclopentaniques en association avec des acides gras de la famille de l'acide 11-hexadecenoique. Chez les phaeophycees, le genre dictyota se caracterise par un fort pourcentage de l'acide 11-hexadecenoique et l'espece ralfsia expensa, par la presence du cholesterol comme sterol majoritaire au lieu et place du fucosterol, caracteristique de cette classe d'algues. L'etude des metabolites secondaires des genres laurencia (rhodophycees) et dictyota (phaeophycees) nous a permis d'isoler et d'identifier huit metabolites dont l'un obtenu a partir de l. Intricata s'est revele etre original. La structure de ce compose a pu etre etablie par des analyses spectroscopiques et par diffraction aux rayons x

APA, Harvard, Vancouver, ISO, and other styles

43

Rohfritsch, Audrey. "Approches phylogénique et phylogéographique du genre Turbinaria (Phaeophyceae) : contribution à l'étude de la structure génétique des populations de Turbinaria ornata en Polynésie française." Polynésie française, 2006. http://www.theses.fr/2006POLF0004.

Full text

Abstract:

Depuis les années 1980, l'algue brune tropicale Turbinaria ornata a développé un caractère invasif en Polynésie française. Différents paramètres de la biologie des populations T. Ornata ont été explorés et semblent contrôlés par des facteurs environnementaux. L'analyse phylogénétique a confirmé le statut d'espèce des taxons étudiés. Des phylogénies reconstruites à plus large échelle géographique avec quatre autres espèces de Turbinaria ont montré de faibles diversités à très large échelle géographique attestant des fortes capacités de dispersion correspondant à la nature potentiellement invasive de ces espèces. Les différents marqueurs moléculaires utilisés pour quantifier les flux de gènes en Polynésie française se sont tous révélés monomorphes à l'exception d'un locus anonyme. Une corrélation significative a été observée entre les fréquences alléliques et l'hydrodynamisme. Les résultats obtenus pourraient remettre en question une origine tahitienne des populations de Rangiroa
In the 1980s, the Indo-Pacific brown alga Turbinaria ornata underwent a population explosion in the high islands of the Society archipelago (French Polynesia). Population biology parameters has been explored and seems to be controlled by environment. The phylogenetic analysis has confirmed the different studied taxa as true species. Phylogenies were constructed at a larger geographical scale with four other Turbinaria species and have shown very small divergences at very large scales testifying the large dispersal capabilities that underscore the potentially invasive nature of the species. Genetic markers were used to estimate gene flow through French Polynesia. All these markers were monomorphic at the Polynesian scale; except one Anonymous locus with two alleles. A significant correlation between allele frequency and hydrodynamism was revealed. Results might even allow us to hypothesise that the Rangiroa populations are not of purely Tahitian origin

APA, Harvard, Vancouver, ISO, and other styles

44

Hotchkiss, Sarah L. "Life history strategies of three species of Cystophora (Phaeophyta, Fucales) from a shallow subtidal community in South Australia /." Title page, contents and summary only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phh832.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Flöthe, Carla [Verfasser], Kai [Akademischer Betreuer] Bischof, and Martin [Akademischer Betreuer] Diekmann. "Ecological effects and underlying molecular mechanisms of grazer-induced defenses in Fucus vesiculosus (Phaeophyceae) / Carla Flöthe. Gutachter: Kai Bischof ; Martin Diekmann. Betreuer: Kai Bischof." Bremen : Staats- und Universitätsbibliothek Bremen, 2014. http://d-nb.info/1072159244/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Wallace, Aaron L. "The taxonomic and systematic relationships of several salt marsh Fucus taxa (heterokontophyta, phaeophyceae) within the Gulf of Maine and Ireland examined using microsatellite markers." View this thesis online, 2005. http://libraries.maine.edu/gateway/oroauth.asp?file=orono/etheses/37803141.pdf.

Full text

Abstract:

Thesis (Ph.D.)--University of New Hampshire (Dept. of Biochemistry and Molecular Biology), 2005.
Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references. Also issued in print.

APA, Harvard, Vancouver, ISO, and other styles

47

Stevens, Erin N. "Photosynthesis in the intertidal macroalga Fucus vesiculosus L. (Phaeophyta) an investigation into the composition of a stored carbon pool /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.49 Mb., 77 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1430763.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Tala, Fadia. "Fenologia e ecofisiologia das macroalgas Porphyra spp. (Bangiales, Rhodophyta) e Lessonia spp. (Laminariales, Phaeophyceae) na costa norte e central do Chile: variações latitudinais e sazonais." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-31032014-110235/.

Full text

Abstract:

O propósito dos estudos fenológicos é descrever e compreender como o desenvolvimento dos organismos ocorre em resposta às variações ambientais que mudam ciclicamente e como certos fatores estimulam a geração de uma cascata de sinais e reações que abrangem desde mudanças moleculares, bioquímicas e fisiológicas, os que acabam se manifestando como padrões anuais de abundância e reprodução. As mudanças ambientais ocorrem em escalas temporais (diárias, sazonais, interanuais) e espaciais (latitudinal, em profundidade, em altitude) e têm um forte impacto no crescimento e desenvolvimento das espécies, em especial de aquelas com características sésseis. O objetivo deste estudo foi caracterizar os padrões fenológicos (sazonais e latitudinais) de abundância, reprodução, fotossíntese e capacidade antioxidante de dois gêneros de macroalgas de importância ecológica e econômica, Porphyra spp. (rodofícea) e Lessonia spp. (feofícea), distribuídas ao longo da costa norte e centro (25° - 34°S) do Chile. Os resultados mostram que variações sazonais de radiação e latitudinais de temperatura influenciam significativamente as respostas fenológicas e ecofisiológicas das espécies estudadas. No caso de Porphyra spp., o ajuste temporal mais notório envolve um desenvolvimento fenológico anual para a população do norte e perene para as do centro e sul. As características fisiológicas mostraram diminuição na eficiência fotossintetizante, pigmentos (clorofila α, carotenoides e ficobiliproteínas) e proteínas solúveis em primavera-verão, acompanhados por aumento da capacidade antioxidante. No caso de Lessonia e embora a abundância não tenha mostrado uma mudança sazonal nas populações, o ajuste temporal mais notório aconteceu nas características fisiológicas, com diminuição na eficiência fotossintetizante, pigmentos (clorofilas α e c, carotenoides), fenois e capacidade antioxidante durante o verão, acompanhado por aumento na absorptância do talo, ETRmax e NPQ. Estudos sobre as identidades taxonômicas das populações de Porphyra são necessários para distinguir entre possíveis padrões devido à caraterísticas da espécie de possíveis variações morfológicas ou ecotípicas. Estudos das espécies de Lessonia próximas aos seus limites de distribuição biogeográfica poderiam elucidar se as diferenças fenológicas e fisiológicas são devido a padrões dependentes das espécies ou são mascaradas por características ambientais locais. Os estudos fenológicos e as mudanças em nível bioquímico/fisiológico podem subsidiar novos destinos da biomassa produzida ou da matéria prima proveniente de organismos de importância econômica. Além disso, alterações nos padrões fenológicos e ecofisiológicos típicos podem direcionar a compreensão sobre os impactos de câmbios ambientais tais como os câmbios climáticos globais, contaminação e poluição, sobrexploração e as interações e dinâmica entre as populações
The purpose of phenological studies is to describe and understand how the development of the organisms occurs in response to environmental variations which change cyclically and how certain factors stimulate the generation of signals and a cascade of reactions from molecular, biochemical and physiological levels, which at the end manifests annual patterns of abundance and reproduction. Environmental changes occur in time scale (daily, seasonal, interannual) and spatial scale (latitudinal, depth, altitude) and have a strong impact on growth and development of the species, especially those with sessile characteristics. The purpose of this study was to characterize the phenology (seasonal and latitudinal) of abundance, reproduction, photosynthesis and antioxidant capacity of two macroalgae with ecological and economic importance, Porphyra spp. (Rhodophyta) and Lessonia spp. (Phaeophyceae), distributed along the coast north and center (25° - 34°S) in Chile. The results show that seasonal changes in radiation and latitudinal temperature significantly influence the phenological and ecophysiological responses of the species studied. For Porphyra spp., the most notorious temporal adjustment involves an annual phenological development from north population in contrast to perennial populations from central and south. The physiological characteristics showed decrease in photosynthetic efficiency, pigments (chlorophyll a, carotenoids and phycobiliproteins) and soluble proteins in spring-summer, accompanied by increasing in antioxidant capacity. For Lessonia spp., although the abundance showed no seasonal changes between the populations, the most notoriously temporal adjustment occurs in physiological characteristics with decrease in photosynthetic efficiency, pigments (chlorophylls a and c, carotenoids), phenols and antioxidant capacity during the summer, followed by increase in thallus absorptance, ETRmax and NPQ. Studies on the taxonomic identity of Porphyra populations are required to distinguish between possible characteristics due to species-specific patterns from morphological or ecotypes variations. Studies in the species Lessonia near their limits of biogeographical distribution could elucidate whether the phenological and physiological differences are due to patterns species-specific or are masked by local environmental characteristics. The phenological studies and changes in the biochemical/physiological levels can subsidize new destination of biomass production and raw material from organisms economically important. Moreover, changes in typical phenological and ecophysiological patterns can give a light about environmental impacts of alterations such as global climate changes, contamination and pollution, overexploitation and interactions and dynamics between populations.

APA, Harvard, Vancouver, ISO, and other styles

49

Rover, Ticiane. "Caracterização estrutural e ultraestrutural do processo de embriogênese de Sargassum Cymosum C. Agardh (Phaeophyceae, Fucales) como modelo de estudo de germinação de algas pardas tropicais e ação da radiação ultravioleta em fases tardias da embriogênese." reponame:Repositório Institucional da UFSC, 2014. https://repositorio.ufsc.br/xmlui/handle/123456789/129642.

Full text

Abstract:

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia Celular e do Desenvolvimento, Florianópolis, 2014
Made available in DSpace on 2015-02-05T21:19:59Z (GMT). No. of bitstreams: 1 329421.pdf: 4339803 bytes, checksum: 994f6e86fd585dbe0f4319d6a52b7510 (MD5) Previous issue date: 2014
Sargassum cymosum é uma alga parda da ordem Fucales, conspícua da flora marinha bentônica de regiões tropicais e temperadas. É encontrada, principalmente, nos costões rochosos protegidos, onde podem formar extensos bancos, sendo assim as algas mais representativas em biomassa e um importante representante na dinâmica ecológica destes ambientes costeiros. Estudos desenvolvidos ao longo de vários anos demonstram o interesse nas algas pardas da ordem Fucales como um modelo de estudo do processo de embriogênese. No entanto, muitos trabalhos referentes a estes processos são encontrados somente para espécies do gênero Fucus e Silvetia, algas presentes predominantemente em regiões frias. Sendo assim, o trabalho visou desenvolver estudos iniciais para a produção de um modelo de estudo de desenvolvimento de uma alga parda de regiões tropicais. O desenvolvimento inicial de zigotos e embriões de S. cymosum foi caracterizado e comparado com o padrão de desenvolvimento estabelecido para todas as algas fucóides, apresentando algumas características que diferem dos demais gêneros como: o zigoto permanece aderido ao receptáculo no inicio do desenvolvimento; a segunda divisão celular que forma a celula rizoidal; o eixo polar e fixado 2 horas após a fecundação e; núcleo extremamente pequeno. Quando analisado o envolvimento dos componentes do citoesqueleto neste processo, pode-se indicar que os microtúbulos e os filamentos de actina tem papel importante no desenvolvimento, pois, as amostras tratadas com colchicina sofreram polarização mas, as divisões celulares não foram observadas e, as tratadas com citocalasina B, alem de não dividir, também não sofreram polarização. Alem do citoesqueleto, o sistema de endomenbranas também mostrou-se importante para o desenvolvimento de S. cymosum, pois quando tratados os zigotos com BFA, inibidor dos corpos de Golgi, este processo foi afetado. Tal tratamento afetou o correto funcionamento dos corpos de Golgi, assim, comprometendo a formação de parede celular e membrana celular, importantes para a determinação do eixo polar, afetando diretamente o dimensionamento do crescimento celular. Também contribuiu para a alta taxa de fusão de vesículas de compostos fenólicos, os fisóides. Esta fusão dos fisóides ocupou grande parte do citoplasma impedindo os demais processos citoplasmáticos, afetando diretamente o desenvolvimento desta alga. Alem disto tudo, os zigotos e embriões são estruturas com simplicidade celular, sendo assim, são extremamente sensíveis aos fatores ambientais. Para avaliar tal característica, plântulas jovens de S. cysomum foram tratadas com radiações UVB e UVA, e associação destas radiações. Estes tratamentos afetaram de diferentes formas as plântulas, com alterações nas taxas de crescimento, principalmente, no tratamento PAR+UVB que apresentou o menor valor; alterou levemente a concentração dos diferentes tipos de pigmentos; redução significativa na concentração de compostos fenólicos e; alterações na morfologia ultraestrutural especialmente nas células corticais com, espaçamento da parede celular, degradação dos fisóides e, alterações nos cloroplastos. Desta forma, as alterações nas condições naturais observadas, especialmente com as variações e aumentando da incidência da radiação UV, poderia afetar o recrutamento de S. cymosum em leitos naturais, com mudanças na estrutura da comunidade e redução da abundância da espécie no ambiente.

Abstract: Sargassum cymosum is a brown algae of the order Fucales, conspicuous benthic marine flora of tropical and temperate regions. It is found, mainly, in protected rocky shores, where they can form extensive banks, thus being the most representative in algal biomass and a major representative of the ecological dynamics of these coastal environments. Studies conducted over several years show interest in brown algae of the order Fucales as a study model of embryogenesis. However, many papers related to these processes are found only for species of Fucus and Silvetia, algae present predominantly in cold regions. Therefore, the initial development work aimed to produce a model for studying the development of tropical brown alga studies. The initial development of zygotes and embryos of S. cymosum was characterized and compared with the established pattern of development for all fucodes algae, presenting some features that differ from other genres such as: the zygote remains attached to the receptacle at the beginning of development; the second cell division that forms the rhizodalccell; the polar axis and fixed 2 h after fertilization and; extremely small nucleous. When examined the involvement of cytoskeletal components in this process, could indicate that microtubules and actin filaments plays an important role in development, for the samples treated with colchicine undergone polarization but cell divisions were observed, and the treated with cytochalasin B, in addition to no cell divisions, did not suffer polarization. Besides cytoskeletal, the endomembranas system also proved important for the development of S. cymosum because when treated the zygotes with BFA, inhibitor of Golgi bodies, this process is affected. Such treatment affected the correct functioning Golgi bodies, thus jeopardizing the cell wall formation and of membrane cellular, important for determining the polar axis, directly affecting the sizing of cell growth. Also contributed to the high rate of vesicle fusion of phenolic compounds, fisodes. This fusion of fisóides occupied much of the cytoplasm, preventing other cytoplasmic processes, directly affecting the development of this alga. Besides all this, zygotes and embryos are cell structures with simplicity, therefore, are extremely sensitive to environmental factors. To evaluate this characteristic, young plants of S. cysomum were treated with UVB and UVA radiation, and combination of these radiations. These treatments affected differently seedlings with changes in growth rates, especially in the treatment PAR + UVB showed the lowest value; slightly alter the concentration of different types of pigments; significant reduction in the concentration of phenolic compounds and; changes in ultrastructural morphology especially in cortical cells with spacing of cell wall degradation fisodes and changes in chloroplasts. Thus, the observed changes in natural conditions, especially with the variations and increasing the incidence of UV radiation could affect the recruitment of S. cymosum in natural beds with changes in community structure and reduction of species abundance in the environment.

APA, Harvard, Vancouver, ISO, and other styles

50

Gager, Leslie. "Composés phénoliques d'algues brunes bretonnes : de la ressources algale à leur extraction éco-responsable et caractérisation chimique jusqu'à leur formulation en cosmétique." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0016.

Full text

Abstract:

La recherche de molécules naturelles dans de nombreux domaines industriels se développe dans une optique d’éco-responsabilité, notamment en cosmétique. Les macroalgues sont une ressource intéressante, riche en de nombreux métabolites tels que les composés phénoliques qui présentent des activités photoprotectrices, antioxydantes ou encore anti-âge. L’objectif de ce travail de thèse était d’analyser les algues brunes bretonnes en termes de composés phénoliques au stade précoce ou au stade macroscopique, obtenir des fractions enrichies en composés phénoliques actifs, les identifier et les inclure dans des formulations cosmétiques. Les résultats de ces travaux ont montré des teneurs élevées en composés phénoliques notamment chez les Fucales et une variation saisonnière de leur teneur pouvant varier selon les espèces.Cette étude a montré que les méthodes alternatives éco-responsables d’extraction et de purification des composés phénoliques permettent d’obtenir des fractions enrichies en ces composés de manière similaire voire supérieure aux méthodes classiques.D’autre part, une analyse HPLC a permis de séparer nos composés d’intérêt, devant cependant être couplée à une méthode de spectrométrie de masse pour permettre l’identification des composés. Enfin, ce travail a mis en évidence la capacité de valorisation en cosmétique des composés phénoliques par leur activité anti-âge et leur stabilité à l’état sec. Leur stabilité au sein de formulation cosmétique reste à être validée dans différentes galéniques, la stabilité d’une seule ayant été testée dans cette étude
The search for natural molecules in many industrial fields is growing with a view to ecoresponsibility, particularly in cosmetics. Seaweeds are an interesting resource as being rich in many molecules such as phenolic compounds with photoprotective, antioxidant and antiaging activities.The aim of this PhD was to analyze brown seaweeds from Brittany (France) in terms of phenolic compounds in the early or macroscopic stages, to obtain fractions enriched in active phenolics, to identify them and to inlude them in cosmetic formulations. The results showed high levels of phenolics, particularly in Fucales, and a seasonal variation in their content according to the species.This study showed that alternative green extraction and purification of phenolics make it possible to obtain fractions enriched in these compounds in a similar or even superior way to conventional methods. On the other hand, an HPLC analysis has separated phenolics, which must be combined with a mass spectrometry method to allow the identification of the compounds. This work has highlighted the ability of phenolics to be recovered in cosmetic products by their antiaging activity and their stability in the dry extract. Their stability within cosmetic formulations has yet to be validated in different galenics, as only one galenic has been tested in this study

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Phaeophycae'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles