Tesis sobre el tema "Ascidians"
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Bromley, Candice Leigh. "The chemistry of Algoa Bay ascidians". Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1020606.
Texto completoParker-Nance, Shirley. "Aplousobranch ascidians (Tunicata: Ascidiacea) from Southern Africa". Thesis, University of Port Elizabeth, 2003. http://hdl.handle.net/10948/311.
Texto completoDavis, Rohan Andrew y davis_rohan@hotmail com. "Chemical Investigations of Great Barrier Reef Ascidians - Natural Product and Synthetic Studies". Griffith University. School of Science, 2000. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030102.104858.
Texto completoGoostrey, Anna. "Aspects of vegetative reproduction and developmental genetics in Diplosoma listerianum (Tunicata, Aplousobranchiata)". Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367481.
Texto completoDa, Silva Liberio Michelle. "Chemical and Biological Investigations of Anticancer Compounds from Australian Ascidians". Thesis, Griffith University, 2014. http://hdl.handle.net/10072/365813.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
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Stacey, Joy E. "The ecophysiology of iron and vanadium accumulation by North Atlantic ascidians /". Internet access available to MUN users only. Search for this title in:, 2009.
Buscar texto completoLotufo, Tito Monteiro da Cruz. ""Ascidiacea (Chordata: Tunicata) do litoral tropical brasileiro"". Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-21052002-125049/.
Texto completoAlthough ascidians are well known in many regions of the globe, information about the group on Brazilian coast are very scanty. Most of the Brazilian coastline is included on the tropical region, which is the poorest known. In order to obtain an inventory of ascidians species on the Brazilian tropical coast, surveys were conducted in different points, ranging from the intertidal to the shallow subtidal depths. Another goal of the present work was to organize all available information through a revision of bibliography and visits to institutions that held representative collections. 61 visits were conducted in places along the coast of the states of Rio de Janeiro, Espírito Santo, Bahia, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte e Ceará. Specimens were collected, examined and identified to the species level. An extensive taxonomic revision was made for every species, by means of literature as well as examination of types and other specimens deposited in different institutions. The present work includes synonymy lists, descriptions, pictures and remarks for each species studied. Keys for all taxa an every category were also included. Up to the present work, 90 species of ascidians had been recorded for Brazil, of which 54 are listed to the State of São Paulo. The surveys revealed a total of 67 species, expanding the list to 98 Brazilian species. Those species are distributed in 2 orders and 3 suborders of the class, with a total of 31 genera included in 14 of the 23 families currently accepted. As an immediate result, were registered 9 new records for Brazilian coast, along with the description of 1 new genus and 10 new species. Furthermore, 8 species have had its taxonomic situation altered by synonymy or separation. The present results, together with data from literature generated tables which were submitted to cluster analysis and a parsimony analysis of endemycity. These analyses revealed a distribution pattern similar to others observed for different benthic taxa. The region studied comprises two provinces, Brazilian Province and Paulista Province.
Davis, Rohan. "Chemical Investigations of Great Barrier Reef Ascidians - Natural Product and Synthetic Studies". Thesis, Griffith University, 2000. http://hdl.handle.net/10072/366561.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
Full Text
Salomon, Christine Elizabeth. "The localization of bioactive secondary metabolities in sponges, ascidians and their associated symbionts /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2001. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035432.
Texto completoTincu, John Andrew. "Acid soluble peptides from the hemocytes of the ascidians : characterization and antimicrobial activity /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3118434.
Texto completoKincaid, Erin Suzanne. "Biofouling Management in the Pacific Northwest and Predation on Native versus Non-native Ascidians". PDXScholar, 2016. http://pdxscholar.library.pdx.edu/open_access_etds/3069.
Texto completoRobinson, Paul A. "Studies towards the synthesis of marine polysulfide natural products". Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6379.
Texto completoRicci, Lorenzo. "A new model to study alternative developments : asexual propagation and regeneration in the basal chordate Botryllus schlosseri". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066683.
Texto completoIn addition to embryogenesis, the colonial ascidians Botryllus schlosseri evolved two alternative developmental pathways leading to the same final structure: the adult body, or zooid. These non-embryonic ontogenesis occur during distinct biological processes: palleal budding (PB) and vascular budding (VB). PB is a process of asexual propagation, with a very stereotyped morphogenesis. Conversely, VB is a purely regenerative phenomenon, induced in the vascular system of the colony by the ablation of all zooids and palleal buds. My research work followed the objective to characterize the molecular and cellular basis of both PB and VB in B. schlosseri. The study of meso-, endo- and ectodermal lineage marker genes revealed the existence of presumptive territories of these lineages in the early palleal and vascular buds and that a single developmental program was launched in both VB and PB. Neural and muscle fates were studied in more detail for PB, indicating a potential double function, both neuro- and myo-genic for the dorsal tube, a structure so far associated with the nervous system only. A detailed morphological description of VB allowed to identify stereotyped stages during early regeneration. Eventually, a transcriptomic characterization of early VB and PB processes initiated an unbiased study of the molecular basis underlying the budding phenomenon in Botryllus. The overall goal of these research works is to unravel the molecular and genetic basis that facilitated, in Botryllus and globally in metazoan, the evolution of alternative developmental pathways
Gineste, Mathieu. "Identification à l'échelle génomique des éléments cis-régulateurs actifs au cours du développement des ascidies". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4095.
Texto completoAscidians display remarkable features within metazoans making them particularly suited for the study of function and evolution of cis-regulatory elements in the context of embryonic development. Ciona intestinalis and Phallusia mammillata, two ascidian species that diverged about 300M years ago, combine high conservation of their developmental processes with high divergence of their genome sequence. To understand how to “make” similar embryos with divergent genomes, we identified active cis-regulatory elements during Ciona intestinalis and Phallusia mammillata development by developing and applying the ChIP-Seq method on histone modifications in early-gastrula embryos. Definition then functional validation of different categories of cis-regulatory elements led us to reveal some features of cis-regulation within compact and highly dynamic genomes. Together, our data constitute a unique functional resource for characterizing cis-regulatory elements in ascidians and questioning their evolution within the Chordates
Barnes, Peter Brendan. "Environmental impacts and the ecology of sponges and ascidians in south-eastern Australian coastal lakes and lagoons". Department of Biological Sciences - Faculty of Science, 2009. http://ro.uow.edu.au/theses/849.
Texto completoNeves, Isabela Monteiro. "Ascídias didemnidae (Tunicata, Ascidiacea) da Região de Bocas Del Toro - Panamá = Didemnidae ascidians (Tunicat, Ascidiacea) from Bocas del Toro - Panamá". reponame:Repositório Institucional da UFPR, 2015. http://hdl.handle.net/1884/37618.
Texto completoDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Zoologia. Defesa: Curitiba, 06/02/2015
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Area de concentração: Zoologia
Resumo: Didemnidae é a família mais diversa e mais derivada da ordem Aplousobranchia (classe Ascidiacea). Compreende cerca de 600 espécies, representando 20% de todas as ascídias conhecidas até o momento. As águas tropicais do Caribe são conhecidas pela riqueza e abundância de invertebrados marinhos e a costa atlântica do Panamá é caracterizada pela presença de um mosaico de hábitats variados que proporcionam importantes substratos naturais para a comunidade incrustante. O presente trabalho apresenta descrições detalhadas de didemnídeos coletados entre os anos de 2003 e 2014 em 12 pontos do arquipélago de Bocas del Toro – Panamá. Foram identificadas 19 espécies, das quais cinco haviam sido registradas na região (Diplosoma listerianum, Lissoclinum verrilli, Didemnum granulatum, D. psammatodes e Trididemnum orbiculatum), sete são novos registros (Lissoclinum abdominale, Didemnum calliginosum, D. cineraceum, D. perlucidum, D. vanderhorsti, Trididemnum palmae e T. thetidis) e sete são espécies novas (Diplosoma sp. nov. 1, Diplosoma sp. nov. 2, Lissoclinum sp. nov. 1, Lissoclinum sp. nov. 2, Didemnum sp. nov., Trididemnum sp. nov. 1 e Trididemnum sp. nov. 2). Com estes resultados, o Panamá está entre as regiões do Caribe com maior número de didemnídeos registrados, mostrando a importância de se considerar a região objeto de esforço no monitoramento e na conservação dos diferentes hábitats e dos invertebrados marinhos que ali habitam. Palavras-chave: Aplousobranchia, ascídias coloniais, características morfológicas, Caribe, Diplosoma, Didemnum, Lissoclinum, taxonomia, Trididemnum, Tunicata.
Abstract: Didemnidae is the most diverse and the more derived family from Aplousobranchia order (Ascidiacea class). Comprising ca. 600 species, that represents 20% of all known ascidians. The Caribbean tropical waters are known for the richness and abundance of marine invertebrates and the Panama Atlantic coast is characterized by the presence of different habitats that provide important natural substrates for sessile communities. This paper reports detailed descriptions of didemnids collected between 2003 and 2014 in 12 points in the archipelago of Bocas del Toro - Panama. Nineteen species were identified, of which five have been previously registered in the region (Diplosoma listerianum, Lissoclinum verrilli, Didemnum granulatum, D. psammatodes and Trididemnum orbiculatum), seven are new records (Lissoclinum abdominale, Didemnum calliginosum, D. cineraceum, D. perlucidum, D. vanderhorsti, Trididemnum palmae and T. thetidis) and seven are new species (Diplosoma sp. nov. 1, Diplosoma sp. nov. 2, Lissoclinum sp. nov. 1, Lissoclinum sp. nov. 2, Didemnum sp. nov., Trididemnum sp. nov. 1 and Trididemnum sp nov. 2). With these results, Panama is among the regions of the Caribbean Sea with the highest number of didemnids, showing the importance of considering the monitoring effort and conservation of different habitats and marine invertebrates that live in this region. Keywords: Aplousobranchia, colonial ascidians, Caribbean Sea, Diplosoma, Didemnum, Lissoclinum, morphology, taxonomy, Trididemnum, Tunicata.
Liu, Boqi. "The gene regulatory network in the anterior neural plate border of ascidian embryos". Kyoto University, 2020. http://hdl.handle.net/2433/253119.
Texto completoTakeara, Renata. "Estudo químico e avaliação da atividade citotóxica das ascídias \'Didemnum psammatodes\' (Sluiter, 1885) e \'Eudistoma vannamei\' Millar, 1977 (Tunicata: Ascidiacea)". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/60/60138/tde-16012007-161004/.
Texto completoSamples of Didemnum psammatodes were collected in Icapui (Ceara State) and Trairi (Ceara State). The methanolic extract from D. psammatodes, acquired from Icapui, was submitted to fractionation and purification through several chromatographic techniques and were obtained four nucleosides (2?-deoxyuridine, 2- deoxyinosine, thyimidine, and 2?-deoxyguanosine), three steroids in mixture (cholestanol, cholestanone, and stigmasterol) and three glyceryl ethers in mixture (2,3-propanediol, 1-(heptadecyloxy), batyl alcohol, and 2,3-propanediol, 1- (nonadecyloxy)). The methanolic extract from D. psammatodes, acquired from Trairi, was initially partitionated, giving rise to aqueous, hexane, chloroform, and butanol phases. The hexane phase inhibited the sea urchin egg cell cycle and exhibited toxicity in tumor cell lines. It was fractionated by several chromatographic techniques and obtained three fatty acid methyl esters in mixture (methyl myristate, methyl palmitate, and methyl stearate), four steroids in mixture (cholestanol and cholestanone), two fatty acids in mixture (palmitic acid and stearic acid) and three glyceryl ethers in mixture (2,3-propanediol, 1-(heptadecyloxy), batyl alcohol, and 2,3- propanediol, 3-(nonadecyloxy)). The chloroform phase also inhibited the sea urchin egg cell cycle and exhibited toxicity in tumor cell lines. It was fractionated through several chromatographic techniques and obtained six fatty acids in mixture (lauric acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, and stearic acid). The aqueous phase was submitted to fractionation and purification by several chromatographic techniques and obtained two nucleosides (uridine and thymidine) and one purinic nucleus (hypoxanthine). The butanol phase resulted in the isolation and identification of two nucleosides (2?-deoxyguanosine and thymidine). Samples of Eudistoma vannamei were collected in São Gonçalo do Amarante (Ceara State). The methanolic extract from E. vannamei was partitionated, giving rise to hexane and hydroalcoholic phases. The hexane phase inhibited the sea urchin egg cell cycle and xiii exhibited toxicity in cell line B-16. It was fractionated by chromatographic techniques and obtained five fatty acid methyl esters in mixture (methyl myristate, methyl palmitate, methyl stearate, methyl palmitoleate, and methyl oleate), two steroids (cholestanol and cholesterol), and five fatty acids (myristic acid, pentadecanoic acid, palmitic acid, margaric acid, and stearic acid). The hydroalcoholic phase resulted in the isolation and identification of two nucleosides (guanosine and adenosine). The substances were identified by spectroscopic and chromatographic methods comparing the obtained values with those of the literature and standards. The nucleosides 2?-deoxyuridine and 2?-deoxyguanosine inhibited the sea urchin egg cell cycle in both stages. The fatty acid methyl esters from D. psammatodes, the palmitic acid plus stearic acid and the glyceryl ethers inhibited the sea urchin egg cell during first cleavage. The fatty acid methyl esters from D. psammatodes presented the highest toxicity in the cell lines tested and the mixture of fatty acid methyl esters from E. vannamei showed toxicity to leukemia cell lines too. Both samples of fatty acid methyl esters showed antiproliferative and cytotoxic effects and these activities involved the inhibition of DNA synthesis and induction of both necrosis and apoptosis.
Guignard, Léo. "Analyse quantitative de la morphogenèse animale : de l'imagerie laser haut-débit à l'embryon virtuel chez les ascidies". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS048/document.
Texto completoAscidian embryos develop with stereotyped and evolutionarily conserved invariant cell lineages to produce in a few hours or days tadpole larvae with a small number of cells. They thus provide an attractive framework to describe with cellular resolution the developmental program of a whole organism. During my PhD, I developed a quantitative approach to describe the evolution of embryonic morphologies during the development of the ascidian Phallusia mammillata. I then used this approach to systematically characterize in detail the logic of cell fate induction events. To quantitatively characterize cell behaviors during embryogenesis, we used multi-angle light-sheet microscopy to image with high spatio-temporal resolution entire live embryos with fluorescently labeled plasma membranes. To extract biological information from this imaging dataset, I then developed a conceptually novel automated method for 4D cell segmentation, ASTEC. Applied to a Phallusia mammillata embryo imaged for 6 hours between the 64-cell and the initial tailbud stages, this method allows the accurate tracking and shape analysis of 1030 cells across 640 cell divisions. The resulting 4D digital embryo can be formalized as a dynamic graph, in which cells are represented by nodes, linked within a time point by edges that represent their spatial neighborhood, and between time points by temporal edges describing cell lineages.Based on this quantitative digital representation, we systematically identified cell fate specification events up to the late gastrula stage. Computational simulations revealed that remarkably simple rules integrating measured cell-cell contact areas with boolean spatio-temporal expression data for extracellular signalling molecules are sufficient to explain most early cell inductions. This work suggests that in embryos establishing precise stereotyped contacts between neighboring cells, the genomic constraints for precise gene expression levels are relaxed, thereby allowing rapid genome evolution
Jimenez, Paula Christine. "BioprospecÃÃo de substÃncias com potencial antitumoral em ascÃdias do litoral cearense: estudos com Eudistoma vannamei Millar, 1977 (Urochordata, Ascidiacea)". Universidade Federal do CearÃ, 2004. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2999.
Texto completoEste trabalho avaliou, inicialmente, a citotoxicidade dos extratos hidroalcoÃlicos das 10 espÃcies de ascÃdias mais abundantes do litoral cearense atravÃs dos seguintes mÃtodos: toxicidade aguda em larvas de artemias, inibiÃÃo do desenvolvimento dos ovos de ouriÃo-do-mar, potencial hemolÃtico e inibiÃÃo da proliferaÃÃo celular de linhagens tumorais. A espÃcie Eudistoma vannamei mostrou-se a mais ativa em 3 dos 4 ensaios performados, sendo, portanto, selecionada para prosseguir com a caracterizaÃÃo quÃmica e farmacolÃgica de seus princÃpios ativos. O extrato foi particionado em diversos solventes e fracionados por cromatografia em sÃlica gel 60 e sephadex LH-20. A atividade das amostras foi monitorada pelo mÃtodo do MTT. Das 60 amostras coletadas, 15 foram ativas. A CI50 dessas 15 amostras foi verificada, novamente pelo mÃtodo do MTT, em 5 linhagens celulares tumorais: CEM, HL-60, MCF-7, HCT-8 e B-16. As fraÃÃes DCM-14 a DCM-18, derivadas da fase diclorometÃnica e quimicamente muito semelhantes entre si, como evidenciado por CCDC, foram as mais ativas, apresentando CI50 de atà 1,0 ug/mL na maioria das linhagens. A dicetopiperazina 6-etilamino-1-metil-piperazina-2,5-diona foi isolada da fase CHCl2 e detectada como o componente majoritÃrio, no entanto, foi inativa sobre a proliferaÃÃo celular. O espectro de H1RNM das fraÃÃes DCM-14 a 18 indicou, como componentes minoritÃrios, uma sÃrie de derivados desta dicetopiperazina, que nÃo foram identificados. O estudo dos efeitos das fraÃÃes sobre a viabilidade (exclusÃo por azul de tripan), proliferaÃÃo (incorporaÃÃo de BrdU e curva de crescimento) e induÃÃo de morte (morfologia celular â coloraÃÃo por H/E â anexina e coloraÃÃo por BE/AO) nas cÃlulas HL-60 demonstrou que DCM-16 e 17 sÃo as mais fortes redutoras da proliferaÃÃo celular. DCM-16 apresentou um pronunciado efeito inibitÃrio sobre a incorporaÃÃo de BrdU, o que pode indicar uma interferÃncia na duplicaÃÃo de DNA. DCM-17 inibiu satisfatoriamente a incorporaÃÃo de BrdU, mas a induÃÃo de apoptose Ã, aparentemente, seu mecanismo predominante. DCM-14 e 15 tambÃm apresentam perfis de indutoras de apoptose celular, sendo que a Ãltima demonstra alguns indÃcios de atividade necrÃtica. Os efeitos de DCM-18 foram pouco pronunciados. As atividades apresentadas por essas fraÃÃes sÃo concentraÃÃo-dependente e o aumento do tempo de contato intensifica o efeito citotÃxico.
The study, initially, evaluated the citotoxity of the hydro-alcoholic extracts of the 10 most abundant ascidian species from the coast of Cearà (Brazil), through the utilization of the following methods: brine shrimps lethality assay; development inhibition of sea urchin eggs; hemolytic potential, and inhibition of in vitro tumor cell growth. In three of the four assays performed, the Eudistoma vannamei species proved to be the most active one, and it was, therefore, selected for chemical and pharmacological characterization of its active principles. The extract was particionated by various solvents and fractionated by chromatography in silica gel 60 and sephadex LH-20 columns. The samplesâ activities were monitored through the MTT method. Of the 60 collected samples, 15 were active. The IC50 of the 15 samples was evaluated through the MTT method, in 5 tumor cell lines: CEM, HL-60, MCF-7, HCT-8 e B-16. The fractions DCM-14 to DCM-18, derived from the CHCl2 phase and chemically very similar to each other, as indicated by CCDC, were the most active ones, presenting IC50 under 1,0 ug/mL in the majority of lines. The diketopiperazine 6-ethylamino-1-methyl-piperazine-2,5-dione was isolated from CHCl2 phase and identified as the major component, however, it was inactive upon cell proliferation. The H1RNM spectra of DCM 14 to DCM 18 fractions showed a number of compounds derived from that major diketopiperazine, which were not identified, as minor components. The study about the fractions effect upon HL-60âs viability (exclusion by trypan blue), proliferation (BrdU incorporation and growth curve) and cell death induction (cell morphology - H/E staining â annexin and BE/AO) revealed DCM-16 and 17 as the most potent cell proliferation reducers. DCM-16 displayed a pronounced BrdU uptake inhibitory effect, which may indicate interference in the DNA duplication process. DCM-17 showed a satisfactorily inhibition upon BrdU uptake, however, the apoptosis induction seems to be its main mode of action. DCM-14 and 15 also displayed a cell apoptosis inductor profile, while the latter indicated some signs of necrotic activity. The activities presented by these fractions are concentration and time dependent as longer periods with cell contact intensifies its citotoxic effect.
Vidal, Patrícia Martins. "Uso de organismos filtradores (ascidiacea) na avaliação da contaminação por mercúrio em ecossistemas costeiros do Estado do Rio de Janeiro". Niterói, 2017. https://app.uff.br/riuff/handle/1/5191.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
necessidade no estabelecimento de prioridades para decisões de gerenciamento ambiental. O objetivo deste trabalho é o uso de organismos filtradores do grupo Ascidiacea como bioindicadores para a avaliação da contaminação em ecossistemas costeiros do Estado do Rio de Janeiro em relação a poluição/risco ecotoxicológico por mercúrio. Foram escolhidas três baías do sistema costeiro do Estado do Rio de Janeiro com diferentes graus de degradação: Baía de Guanabara (BG) amplamente poluída; Baía de Sepetiba (BS), com algumas áreas contaminadas e Baía da Ribeira (BR), com alterações antrópicas localizadas. Em cada baía, foi selecionado um ponto de coleta e capturados, durante a maré baixa, aproximadamente trinta indivíduos. As ascídias coletadas foram colocadas em sacos plásticos, lacrados, identificados e congelados. Uma vez no laboratório, os organismos foram identificados, a nível de espécie, e pesados (peso úmido). A determinação das concentrações de mercúrio total (HgT) nos organismos foi realizado no Laboratório de Especiação de Mercúrio Ambiental (LEMA) no CETEM/MCT. Para tal, foi utilizado um aparelho de absorção atômica portátil (LUMEX), específico para análises de HgT por espectrofotometria de absorção baseada no diferencial Zeeman. A determinação do metal foi feita tanto na parte interna das ascídias quanto em sua túnica de revestimento. Para a espécie Styela plicata, encontrada na BG e BS, apesar de não haver diferença significativa, foram observadas maiores [HgT], tanto na túnica quanto na parte interna, nas ascídias de BS. Tais resultados tornam-se mais evidentes ao comparamos as estações Pilar Niterói (ambiente altamente poluído) e Pilar Canal Central (ambiente menos poluído devido à intensa circulação das águas) da BG, tanto entre si, quanto em relação às amostras dessa espécie na BS. Em relação à Phallusia nigra, espécie encontrada na BR, a [HgT] foi maior na parte interna desses organismos do que os da BG e BS. As maiores [HgT] foram observadas na túnica, para as três baías, e não houve diferença significativa entre elas. Não houve correlação entre o peso (tamanho) das ascídas e a [HgT] em seus tecidos. Como a composição bioquímica da túnica de ambas as espécies é similar, a explicação da diferença de concentração do metal entre elas pode residir no fato das células morulares da P. nigra realmente acumularem maior concentração de HgT do que as células de S. plicata. A estimativa dos valores de FBC para ascídia S. plicata, é maior na BS do que na BG. O mesmo resultado foi observado quando comparado ao FBC das ascídias da BR, indicando uma maior disponibilidade do Hg em ambientes menos poluídos. Este primeiro estudo realizado no país, foi uma tentativa preliminar de avaliação das ascídias como potenciais bioindicadoras de contaminação por Hg. Portanto, como são organismos sésseis e filtradores, um maior esforço amostral para confirmar se a espécie Styela plicata pode estar presente na BR como sugerido no estudo, a fim de possibilitar uma análise comparativa mais completa em termos da gradação da contaminação por mercúrio.
The use of indicators of ecological risk due to pollution of water bodies is a need to establish priorities for environmental management decisions. The objective of this study is the use of filter feeding organisms of ascidians as bioindicators for the assessment of contamination in coastal ecosystems of the State of Rio de Janeiro in relation to pollution / ecotoxicological risk by mercury. We chose three bays of the coastal system of the State of Rio de Janeiro with different degrees of degradation: the Bay of Guanabara (BG) widely polluted; Sepetiba Bay (SB), with some contaminated areas and the Ribeira Bay (RB), with anthropogenic changes located. In each bay, was selected a collection point and captured during low tide, about thirty individuals. The ascidians collected were placed in plastic bags, sealed, identified and frozen. Once in the laboratory, organisms were identified to species level, and weighed (wet weight). The determination of concentrations of total mercury (THg) in organisms was performed at the Laboratory of Environmental Mercury Speciation (LEMA) in CETEM / MCT. To this end, we used a portable atomic absorption apparatus (LUMEX), specific analyzes of THg absorption spectrophotometry based on differential Zeeman. The determination of metal was done both on the inside of ascidians and in his coat lining. For the species Styela plicata, found in the BG and BS, although no significant differences were observed higher [THg] in both the tunica and inside, in ascidians BS. These results become more evident when comparing stations Pilar Niterói (highly polluted environment) and Pilar Central Canal (cleaner environment due to the intense movement of water) BG, both among themselves and in relation to samples of this species in the BS. Regarding Phallusia nigra species found in BR, [THg] was greater in the inner part of the bodies of BG and BS. The highest [THg] were observed in the tunica, for the three bays, and there was no significant difference between them. There was no correlation between the weight (size) of ascídas and [THg] in their tissues. As the biochemical composition of the coat of both species is similar, the explanation of the difference in concentration of the metal between them may lie in the fact that morulares cells of P. nigra actually accumulate THg higher concentration of cells of S. plicata. The estimated values for FBC ascidian S. plicata, the BS is greater than the BG. The same result was observed when compared to the FBC squirts of BR, indicating a greater availability of Hg in less polluted environments. This first study in the country, was a preliminary attempt to evaluate the ascidians as potential bioindicators of Hg contamination. Therefore, as filtrating and sessile organisms is a major effort to confirm that the sample species Styela plicata BR may be present as suggested in the study in order to facilitate a more complete comparative analysis in accordance with the gradation of mercury contamination.
Evans, Rowan. "Reproduction of the unitary, larviparous ascidian Dendroda grossularia". Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260360.
Texto completoMadgwick, Alicia. "Evolution des programmes transcriptionnels développementaux des ascidies Ciona robusta et Phallusia mammillata". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT137/document.
Texto completoHow can embryonic morphogenesis be evolutionarily conserved in spite of extensive divergence in coding and non-coding genome sequences? To address this question, we worked on the early development of two very divergent ascidians, Phallusia mammillata and Ciona intestinalis. These species share an almost identical early morphogenesis and stereotyped cell lineages. Remarkably, however, their genomes are divergent to the extent that their non-coding sequences cannot be aligned and gene order has not been conserved.We focus our attention on the behaviour of endoderm precursors throughout two important evolutionarily conserved developmental processes: initial fate specification and early gastrulation. We first compared by in situ hybridisation the transcriptional expression of orthologous regulatory genes in Phallusia and in Ciona. We found that the endodermal expression of 8 regulatory genes known to be involved in these developmental processes is qualitatively conserved between the two species.To study how these genes conserved their regulation in spite of extensive non-coding sequence divergence, we collaborated with the Gomez-Skarmeta lab to map, by ATAC-seq, open chromatin regions in both species to identify active regulatory regions genomewide. Three quarters of the 39 open chromatin regions for endodermal genes behaved as active regulatory sequences by the larval stage, when tested by electroporation in embryos. Many of the tested sequences had conserved cis-regulatory activity in both species in spite of sequence divergence. We have identifed putative transcription factor binding sites in endodermal enhancers in both species to identify conserved upstream regulators shared between Phallusia and Ciona.Taken together our results suggest that extensive transcription factor binding site turn over, without radical change in GRNs architecture, may explain the qualitative conservation of gene expression patterns between highly divergent ascidian genomes. Furthermore, we found that shadow enhancers are much more prevalent than initially anticipated.Taken together our results suggest that extensive transcription factor binding site turn over, without radical change in GRNs architecture, may explain the qualitative conservation of gene expression patterns between highly divergent ascidian genomes. Furthermore, we found that shadow enhancers are much more prevalent than initially anticipated
西川, 輝昭, Teruaki Nishikawa, D. D. Bishop John y Dorothea Sommerfeldt A. "Occurrence of the alien ascidian Perophora japonica at Plymouth". Cambridge University Press, 2000. http://hdl.handle.net/2237/10552.
Texto completoJohnson, Sheri L. "Mating System Dynamics in a Free-Spawning Colonial Ascidian". Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/JohnsonSL2007.pdf.
Texto completoBevis, Peter John. "Studies on gastrointestinal peptides in the ascidian Styela clava". Thesis, Royal Holloway, University of London, 1985. http://repository.royalholloway.ac.uk/items/2ce39101-08bf-48be-be30-1042d191f253/1/.
Texto completoPeddie, Clare M. "Lymphocyte-like functions in the solitary ascidian Ciona intestinalis". Thesis, University of St Andrews, 1995. http://hdl.handle.net/10023/13994.
Texto completoOrdóñez, Sánchez Víctor. "Ecología y genética de ascidias invasoras en el Mediterráneo occidental". Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/128963.
Texto completoBiological invasions are of special concern to marine biologists. The Mediterranean is one of the most harmed seas by human activities. Among invasive marine organisms, ascidians have become a global problem. The main goal of this PhD thesis is to study ecological and genetic aspects of the biology of four invasive ascidians in the western Mediterranean. In the first chapter, we delve into the post-border processes of the ascidian Microcosmus squamiger studying its population genetic structure. This ascidian has a relatively high capacity of post-border dispersion, which allows gene flow between populations on a small scale. Moreover there are two genetic clusters related to the two original sources of the introduced worldwide populations. These genetic pools are mixed at the population level but not at the individual level. In the second chapter, we evaluate biological interactions in early-life history stages of Microcosmus squamiger and Styelaplicata, among themselves and with mussels. No interactions between the two ascidians were found in fertilization or larval settlement and metamorphosis processes. In contrast, larvae of both ascidians were consumed by the juvenile mussels, and the ascidians also presented shifts in larval behavior in the presence of the mussels. This highlights the importance of the resident community for the establishment of introduced species. In the third chapter, we study the life cycle and population genetic structure of the invasive Didemnum vexillum. The ascidian showed a marked seasonal growth and reproductive cycle, negatively influenced by warm summer temperatures. Additionally, introduced populations in the Mediterranean showed low diversity, suggesting a bottleneck process in the introduction. Finally, in the fourth chapter, we study the life cycle of Clavelina oblonga. This ascidian is in fact an introduced species in the Mediterranean for more than 80 years ago but was erroneously identified as C. phlegraea, native to the region. Their reproductive and growth cycle was markedly seasonal, favored by warm summer temperatures, hibernating in colder months.
Khandelwal, Mudrika. "Structure and processing of fibrous cellulose : bacterial and ascidian material". Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/244716.
Texto completoCleto, Cynthia. "Analysis of transcriptional elements of an ascidian troponin I gene". Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33733.
Texto completoPemberton, A. J. "Aspects of mate choice in the colonial ascidian Diplosoma listerianum". Thesis, University of Aberdeen, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.593279.
Texto completoRocha, Rosana Moreira da. "Ascidias coloniais do canal de São Sebastião, SP : aspectos ecologicos". [s.n.], 1988. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316337.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Apesar dos Ascidiacea constituirem um grupo muito comum nos costões rochosos do litoral de São Paulo, foram muito pouco estudados, principalmente no que se refere aos aspectos da biologia e ecologia das espécies. No Canal de São Sebastião existe uma fauna diversificada de ascídias coloniais que recobre a face inferior de pequenos blocos de rocha, tocas e frestas. O interesse em estudar alguns aspectos da biologia das espécies, suas interações na comunidade e a influência dos mesmos na colonização e manutenção do espaço foi o que levou à execução deste trabalho. O estudo do período reprodutivo foi feito através da imersão mensal de placas de recrutamento de lajota natural. O estudo da forma e velocidade de crescimento e da sucessão de ascídias coloniais, incluindo observações sobre interações entre as espécies, foi feito através do acompanhamento de placas artificiais durante 9 meses, imersas em duas épocas diferentes (verão e inverno). As cinco espécies estudadas em maior detalhe foram: Didemnum speciosum, Diplosoma macdonaldi, Clavelina oblonga, Symplegma viride e Botrylloides nigrum, pois eram as mais frequente no substrato artificial. Estas espécies apresentaram período reprodutivo longo com interrupção nos meses mais frios, observada em C. oblonga e B. nigrum. ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: Although ascidians are very abundant on rocky shores of the Southeastern Brazilian coast (Sao Paulo State), there is little information about the species biology and ecology. In the São Sebastião Channel occurs a diversified fauna of compound ascidians, which cover the underside surface of boulders, crevices and cracks. To fulfill this gap of knowledge, the study of some life-history features of the ascidian species their interrelations in the community and how these aspects influence their colonization and space maintenance ability was undertaken. The reproductive period was determined by observations of one-month submerged artificial plates throughout one year, and by dissecting colonies to look for larvae. The ascidian community succession starting on clean plates were monthly observed on 9 month submerged plates, .on which the shape and growth rate of the colonies was also analyzed. Five species were discussed: Didemnum speciosum, Diplosoma macdonaldi, Clavelina oblonga, Symplegma viride e Botrylloides nigrum. They showed a long reprodutive period with a short interruption in C. oblonga and B. nigrum during winter. ...Note: The complete abstract is available with the full electronic digital thesis or dissertations
Mestrado
Mestre em Ecologia
Casso, Carrasco Maria. "Genomic analysis of an introduced ascidian and implications for invasiveness". Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/673998.
Texto completoYu, Deli. "Temporal control of muscle gene expression in an ascidian embryo". Kyoto University, 2019. http://hdl.handle.net/2433/242897.
Texto completoStoner, Douglas Steven. "Life History and Populationi Biology of the Colonial Ascidian Diplosoma Similis". Thesis, University of Hawaii, Honolulu, 1989. http://hdl.handle.net/10125/18144.
Texto completoTypescript. Thesis (Ph. D.)--University of Hawaii at Manoa, 1989. Includes bibliographical references.
Mortimer, Sandra 1981. "Experimental analysis of trans-splicing of an ascidian troponin I gene". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101643.
Texto completoDavis, Martin Herbert. "Physical factors influencing larval behaviour in three species of solitary ascidian". Thesis, Open University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388307.
Texto completoMilne, Bruce Forbes. "Theoretical studies of cyclic octapeptides from the marine ascidian Lissoclinum patella". Thesis, University of Aberdeen, 2002. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU168052.
Texto completoOlguín, Uribe Guillermo. "L'ascidie mexicaine Stomozoa murayi (Kott, 1957) : chimie et écologie chimique en rapport avec son environnement bactérien". Perpignan, 1997. http://www.theses.fr/1997PERP0288.
Texto completoCallahan, Ashley G. "Harbour survey and genetic analysis of non-indigenous ascidian tunicates in Newfoundland /". Internet access available to MUN users only. Search for this title in:, 2009.
Buscar texto completoDias, Gustavo Muniz. "Estrutura de comunidade e variabilidade genetica de ascidias coloniais do entremares rochoso". [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316080.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Mestrado
Ecologia
Mestre em Ecologia
Green, Kathryn Margaret. "Morphological changes during normal and pertubed metamorphosis of the ascidian herdmania curvata /". St. Lucia, Qld, 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16468.pdf.
Texto completoKhare, Parul. "CIS-regulatory elements driving muscle-specific expression of an ascidian troponin I gene". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84044.
Texto completoPrünster, Maria Mandela. "De novo myogenesis and neurogenesis during budding of the colonial ascidian, Botryllus schlosseri". Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS586.
Texto completoThe aim of this work is to describe via molecular-biological methods the asexual form of development of the colonial ascidian Botryllus schlosseri focusing on the formation of different tissues, namely muscles and nervous system, as well as exploring the potential presence of structures or cells homologous to the neural crest. Ascidians belong to the subphylum tunicates, sister group of vertebrates and are the closest relatives to man that can reproduce asexually, by budding. As colonial ascidian, the metamorphosis of Botryllus schlosseri specimen is followed by a lifelong, recurring, highly coordinated budding process, where multiple individuals (zooids) are connected and embedded in a common tunic. During asexual development, zooids can develop in a direct manner without embryonic and larval stages. To study the cellular origin and mechanisms of non-embryonic myogenesis I followed the expression pattern and dynamics of myogenic genes during asexual development and reconstructed muscle precursors. Orthologs of these genes are not only expressed during muscle formation via larval development but also during the formation of cardio-pharyngeal muscles in the vertebrate embryogenesis. I further drew a comparison of the regionalization of a transitory neurogenic structure, the dorsal tube, along the anteroposterior axis during budding with its larval counterpart, the neural tube, thus adding a RNA-expression profile of neural genes hereby proposing a scenario of cerebral ganglion formation by delamination. To better understand the nature of the dorsal tube and gangliogenesis I investigated potential involvement gene orthologs implemented in vertebrate neural crest formation
Corbo, Joseph C. "Molecular aspects of notochord and nervous system development in the ascidian, Ciona intestinalis /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9735267.
Texto completoVirata, Michael J. "A novel invertebrate chordate model for Alzheimer's disease using the ascidian ciona intestinalis". Diss., [La Jolla, Calif.] : [San Diego] University of California, San Diego ; San Diego State University, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3372801.
Texto completoTitle from first page of PDF file (viewed October 22, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
Yagi, Kasumi. "Studies on function of Zic family transcription factor genes in early ascidian embryos". 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147859.
Texto completoPaiva, Amarilis Brandão de. "Estudo comparativo das assembleias de ascidias em duas regiões portuárias da costa brasileira". reponame:Repositório Institucional da UFC, 2013. http://www.repositorio.ufc.br/handle/riufc/13954.
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The intensification of the maritime transport around the world is coupled with an increase in the harbors and dockings infrastructure. These structures provide hard substrata for a generally abundant and diverse encrusting fauna. It has been demonstrated that artificial substrata in ports and marinas may harbor a considerable amount of exotic species. Ascidians are among the most important groups in such environments, being transported in the hulls or ballast water of ships connecting different regions. The present study investigate the assemblage of ascidians encrusting settling plates in two different harbor areas, distant more than 20º of latitude along the Brazilian coast. The polystyrene settling plates measured 12 x 12 cm were arranged in pairs, forming a “sandwich” with a 2cm space between them, and were kept submerged for periods of three months and one year, while the experiment lasted two years. The species richness of both areas was just slightly different (33 species in Ceará and 31 in São Paulo). On the other hand, Ceará presented a larger species richness per plate than São Paulo. In São Paulo, at the limit of the tropics, a stronger influence of seasonality was detected in terms of species composition between different periods. The compositions of the assemblages from the plates submerged for three months and one year was also different. The assemblage recruiting the internal and external faces of the plates sets were also different in terms of specific composition. The yearly plates presented a lower coverage of ascidians when compared to the quarterly plates, with a corresponding increase in coverage for other groups such as sponges and bryozoans. The internal faces of yearly plates showed a greater abundance of solitary ascidians, mainly Ascidia sydneiensis. The species Rhodosoma turcicum was recorded for the first time in the northern Brazilian coast. The presence of many exotic or cryptogenic species at the studied areas highlights the importance of continuous regular monitoring of the encrusting fauna in harbors and marinas.
A intensificação do transporte marítimo ao redor do mundo vem aumentando junto com a infraestrutura de áreas portuárias. Estas estruturas proporcionam substratos rígidos que passam a abrigar uma fauna incrustante, em geral, rica e abundante. Já se demonstrou que substratos artificiais nestas áreas podem abrigar um contingente considerável de espécies exóticas. Dentre os grupos que recrutam em tais ambientes, as ascídias se destacam, podendo ser transportadas por navios entre diferentes regiões, tanto por água de lastro como por incrustações nos cascos. Neste trabalho foi realizado um levantamento das assembleias de ascídias que incrustam em placas de recrutamento artificiais, em duas regiões portuárias com mais de 20º de diferença latitudinal na costa brasileira. Os experimentos foram realizados no Porto do Pecém – CE e em uma marina no canal de São Sebastião – SP. Foram utilizados pares de placas de polietileno (12 x 12 cm), espaçadas em 2 cm formando “sanduíches”, submersas por períodos de três meses e de um ano para verificar o recrutamento da comunidade incrustante. O experimento teve duração de dois anos. A riqueza de ascídias encontrada em cada local não foi muito diferente (33 espécies no Ceará e 31 em São Paulo). No entanto, o Ceará, região de menor latitude, apresentou uma maior riqueza por placa. Em São Paulo, latitude subtropical, verificou-se uma maior influência da sazonalidade na composição das espécies dos diferentes períodos. Foram observadas diferenças nas composições das placas de três meses com as de um ano de submersão e também diferenças na composição das assembleias de ascídias nas faces internas e externas dos pares de placas. Comparando as placas trimestrais e anuais, foi detectada uma menor porcentagem de cobertura pelas ascídias nas placas anuais externas, ocorrendo aumento de outros grupos, principalmente esponjas e briozoários. Nas faces internas das placas anuais ocorre aumento da abundância de ascídias solitárias, principalmente da espécie Ascidia sydneiensis. A presença da ascídia Rhodosoma turcicum em placas do Ceará caracterizou o primeiro registro desta espécie para o nordeste setentrional brasileiro. A presença de muitas espécies exóticas e criptogênicas nas regiões de estudo alerta para a importância de monitoramentos contínuos das espécies em regiões portuárias.
Häussler, Maximilian. "Prediction of tissue-specific cis-regulatory sequences : application to the ascidian Ciona intestinalis and the anterior neurectoderm". Paris 11, 2009. http://www.theses.fr/2009PA112078.
Texto completoIn this thesis, a procedure is presented to rank combinations of short sequence motifs by their distribution around a set of genes. The better a combination matches around genes expressed in a certain tissue, the higher is its score. I applied this to an already characterized enhancer of C. Intestinalis expressed in the anterior neurectoderm which had been found by systematic mutations to be composed of a duplicated structure. The results of my procedure indicated that duplicated GA TTA-sites are an essential feature of cis-regulatory elements active in the anterior neurectoderm. Searching the genome for matches to this signature resulted in putative enhancers that drive a reporter gene in 50% of the cases in the anterior neurectoderm. In addition, I tried to improve the curation of already published cis-regulatory elements by extracting them automatically from the full text of the biological research articles. Thanks to the thriving open access publishing model and the improvement in experimental assays, more and more of this data is becoming available. Finally, I showed that in the absence of non-coding sequence alignments between the genomes of vertebrate and C. Intestinalis, one can nevertheless find a handful of loci with a very unusually conserved gene order. In these cases, the cis-regulatory search space is reduced to a set of introns, some of which were recently shown to harbor enhancers. Many of these loci have not been analyzed yet. Together, these computational approaches should lead to a better characterization of cis-regulatory sequences and pave the way for further experimental validations
Haupaix, Nicolas. "Régulation de la voie MEK/ERK par la signalisation éphrine lors du développement neural chez l'ascidie Ciona intestinalis". Phd thesis, Université Nice Sophia Antipolis, 2014. http://tel.archives-ouvertes.fr/tel-01059798.
Texto completo