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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Characterization and subunit structure of the hemocyanin of a polyplacophoran, Katherina tunicata (Wood)

Ryan, Margaret Colette, 1956- 06 1900 (has links)
x, 76 leaves : ill. ; 28 cm Typescript. (Another copy on microfilm is located in Archives) Thesis (M.S.)--University of Oregon Includes vita and abstract Bibliography: leaves 70-76 University of Oregon theses, Dept. of Biology, M.S., 1980
12

Molecular embryology of a larvacean urochordate, Oikopleura dioica, and the origin of chordate innovations

Bassham, Susan Lee January 2002 (has links)
Typescript. Includes vita and abstract. Also available for download via the World Wide Web; free to University of Oregon users. Bibliography: Includes bibliographical references (leaves 125-138). Description: xii, 138 leaves : ill. (some col.) ; 29 cm.
13

Spatial and temporal analysis of the growth dynamics of the ascidian Perophora viridis

Roman, Arte C. 01 April 2001 (has links)
No description available.
14

Filogenia molecular de Tunicata com Ãnfase em Ascidiacea / Filogenia molecular de Tunicata com Ãnfase em Ascidiacea

Daniele Pequeno Lopes 20 April 2006 (has links)
CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Por muitos anos a filogenia de muitos grupos animais permaneceu obscura para os zoÃlogos, pois o uso de marcadores morfolÃgicos muitas vezes leva a um resultado insatisfatÃrio. A partir do advento de tÃcnicas moleculares, as relaÃÃes de parentesco de diversos tÃxons puderam ser analisadas, quationando visÃes filogenÃticas anteriores baseadas em dados fisiolÃgicos, morfolÃgicos, de registro fÃssil entre outros. Desse modo, ocorreu um grande desenvolvimento da produÃÃo cientÃfica que envolvia o estudo da filogenia dos mais diversos grupos, entre eles, Tunicata e Ascidiacea. Apesar da existÃncia de diversos trabalhos que propÃem uma anÃlise das relaÃÃes de parentesco de tais tÃxons, ainda hà dados bastante conflitantes que nÃo levam a um resultado final esclarecedor. O presente trabalho teve como objetivo compreender melhor a filogenia de Tunicata, com Ãnfase nos Ascidiacea, utilizando a anÃlise da regiÃo 18S do nrDNA de Microcosmus exasperatus, que foi obtido mediante extraÃÃo baseada no reagente CTAB, e de outras espÃcies cujas sequÃncias encontravam-se disponÃveis no GenBank. Para obtenÃÃo da seqÃÃncia alvo, as reaÃÃes de PCR foram realizadas utilizando iniciadores universais que flanquearam tal regiÃo, sendo obtida uma seqÃÃncia consenso que foi utilizada para a construÃÃo dos cladogramas. A partir das anÃlises dos cladogramas gerados foi possÃvel obter indicaÃÃes de que Chordata e seus subfilos sÃo monofilÃticos. Quanto aos representantes de Tunicata, Appendicularia ficou caracterizado como o grupo mais basal. NÃo foi possÃvel a confirmaÃÃo da divisÃo do grupo Ascidiacea em duas ordens: Pleurogona e Enterogona. Contudo, Phlebobranchia, Aplousobranchia e Stolidobranchia foram confirmados para a maioria das Ãrvores. Appendicularia foi considerado monofilÃtico, enquanto Ascidiacea e Thaliacea foram identificados como parafilÃticos, sendo que este Ãltimo mostrou-se prÃximo das ascÃdias flebobranquias. Com relaÃÃo a Stolidobranquia, seu monofiletismo foi demonstrado em grande parte dos cladogramas obtidos, apresentando Molgulidae como um grupo monofilÃtico mais basal. Os Phlebobranchia configuraram um clado monofilÃtico, incluindo a famÃlia Cionidae como um dos seus representantes. / Phylogenetic relationships among many animal groups have been considered unclear by zoologists for many years, as morphological markers sometimes led to unsatisfactory results. The development of molecular techniques allowed the understanding of evolutionary relationships of many taxa, questioning previous phylogenetic recosntructions based on physiological and morphological aspects, fossil records, and other sources of data. As a result, there was a great development of scientific production regarding phylogenetic studies of distinct groups, including Tunicata and Ascidiacea. Despite the many works proposing hypothesis about relationships between those taxa, there are many conflicting data. The aim of the present work is to review the phylogeny of Tunicata, focusing on the taxon Ascidiacea, by analyzing the 18S nrDNA region of Microcosmus exasperatus, which was obtained through extraction based on CTAB reagent, along wiht other species whose sequences were available on GenBank. In order to achieve the desired target sequence, PCR reactions using universal primers that matched that region were performed and the consensus sequence obtained was compared to other sequences to produce phylogenetic trees. Tha analysis of the cladograms obtained indicated that Chordata and its subphyla are indeed monophyletic. Regarding the Tunicata, Appendicularia was identified as the most basal group. It was not possible to confirm the division of Ascidiacea into two distinct orders: Pleurogona and Enterogona. However, Phlebobranchia, Aplousobranchia and Stolidobranchia were present in most of the trees. Appendiculariaa was considered monophyletic, and Ascidiacea and Thaliacea were identified as paraphyletic groups, where the latter presented a close relationship with phlebobranch ascidians. Stolidobranchia appeared as a monophyletic group in most of the cladograms, showing Molgulidae also as monophyletic in a basal position. Phlebobranchia is also monophyletic and included the family Cionidae as one of its representatives.
15

"Ascidiacea (Chordata: Tunicata) do litoral tropical brasileiro" / "Ascidiacea (Chordata: Tunicata) from brazilian tropical coast"

Lotufo, Tito Monteiro da Cruz 08 May 2002 (has links)
Embora tenham sido muito estudadas em diversos pontos do globo, as ascídias do litoral brasileiro são pouco conhecidas. A maior parte do litoral brasileiro está incluída na região tropical, para qual as informações são mais escassas. Com o intuito de se conhecer a fauna de ascídias do litoral tropical brasileiro foram realizadas diversas coletas em diferentes pontos desta região, abrangendo desde a zona entremarés até o infralitoral raso. Outro objetivo do presente trabalho foi o de organizar as informações já existentes a partir de revisão bibliográfica e visitas a algumas instituições que continham coleções representativas. Foram realizadas ao todo 61 coletas em pontos distribuídos entre os estados do Rio de Janeiro, Espírito Santo, Bahia, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte e Ceará. Os animais foram coletados, examinados e identificados até o nível de espécie. Para cada espécie se procurou fazer um extensa revisão taxonômica, tanto a partir da literatura como do exame de tipos depositados em diferentes instituições. O presente trabalho inclui listas sinonímicas, descrições e comentários para cada espécie estudada, com fotografias para a maior parte. Foram adicionadas ainda chaves dicotômicas para todos os táxons, em todas as categorias. Até a realização deste trabalho, 90 espécies de ascídias haviam sido registradas no litoral brasileiro, das quais 54 estão listadas para o estado de São Paulo. Com a realização das campanhas de coletas foram identificadas 67 espécies que, juntamente com uma revisão criteriosa da literatura e o exame de vários tipos e outros exemplares de outras regiões do mundo, fizeram com que a lista atualizada inclua 98 espécies. Estas espécies estão distribuídas entre as 2 ordens e 3 subordens da classe, com um total de 31 gêneros incluídos em 14 dentre as 23 famílias propostas atualmente. Como resultado imediato foram registradas 9 novas ocorrências para o litoral brasileiro, com a descrição de 1 gênero e 10 espécies novas. Além disso, 8 espécies tiveram sua situação alterada por sinonimia ou separação. Juntamente com outros dados da literatura, as tabelas de ocorrências foram submetidas a uma análise de agrupamento e uma análise de endemicidade por parcimônia. As análises evidenciaram um padrão de distribuição semelhante àquele observado para outros grupos bentônicos sésseis, com a divisão da região estudada em duas províncias, a Província Brasileira e a Província Paulista. / Although 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.
16

"Ascidiacea (Chordata: Tunicata) do litoral tropical brasileiro" / "Ascidiacea (Chordata: Tunicata) from brazilian tropical coast"

Tito Monteiro da Cruz Lotufo 08 May 2002 (has links)
Embora tenham sido muito estudadas em diversos pontos do globo, as ascídias do litoral brasileiro são pouco conhecidas. A maior parte do litoral brasileiro está incluída na região tropical, para qual as informações são mais escassas. Com o intuito de se conhecer a fauna de ascídias do litoral tropical brasileiro foram realizadas diversas coletas em diferentes pontos desta região, abrangendo desde a zona entremarés até o infralitoral raso. Outro objetivo do presente trabalho foi o de organizar as informações já existentes a partir de revisão bibliográfica e visitas a algumas instituições que continham coleções representativas. Foram realizadas ao todo 61 coletas em pontos distribuídos entre os estados do Rio de Janeiro, Espírito Santo, Bahia, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte e Ceará. Os animais foram coletados, examinados e identificados até o nível de espécie. Para cada espécie se procurou fazer um extensa revisão taxonômica, tanto a partir da literatura como do exame de tipos depositados em diferentes instituições. O presente trabalho inclui listas sinonímicas, descrições e comentários para cada espécie estudada, com fotografias para a maior parte. Foram adicionadas ainda chaves dicotômicas para todos os táxons, em todas as categorias. Até a realização deste trabalho, 90 espécies de ascídias haviam sido registradas no litoral brasileiro, das quais 54 estão listadas para o estado de São Paulo. Com a realização das campanhas de coletas foram identificadas 67 espécies que, juntamente com uma revisão criteriosa da literatura e o exame de vários tipos e outros exemplares de outras regiões do mundo, fizeram com que a lista atualizada inclua 98 espécies. Estas espécies estão distribuídas entre as 2 ordens e 3 subordens da classe, com um total de 31 gêneros incluídos em 14 dentre as 23 famílias propostas atualmente. Como resultado imediato foram registradas 9 novas ocorrências para o litoral brasileiro, com a descrição de 1 gênero e 10 espécies novas. Além disso, 8 espécies tiveram sua situação alterada por sinonimia ou separação. Juntamente com outros dados da literatura, as tabelas de ocorrências foram submetidas a uma análise de agrupamento e uma análise de endemicidade por parcimônia. As análises evidenciaram um padrão de distribuição semelhante àquele observado para outros grupos bentônicos sésseis, com a divisão da região estudada em duas províncias, a Província Brasileira e a Província Paulista. / Although 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.
17

Estrutura de comunidade e variabilidade genetica de ascidias coloniais do entremares rochoso

Dias, Gustavo Muniz 03 August 2018 (has links)
Orientadores: Luiz Francisco Lembo Duarte, Vera Nisaka Solferini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-03T20:54:04Z (GMT). No. of bitstreams: 1 Dias_GustavoMuniz_M.pdf: 55978490 bytes, checksum: ce5edb29ed334ed2e7fcc280a376a9f4 (MD5) Previous issue date: 2004 / Mestrado / Ecologia / Mestre em Ecologia
18

Automated detection of ncRNAs in the draft genome sequence of a colonial tunicate

Velandia-Huerto, Cristian A., Gittenberger, Adriaan A., Brown, Federico D., Stadler, Peter F., Bermúdez-Santana, Clara I. 05 September 2016 (has links) (PDF)
Background: The colonial ascidian Didemnum vexillum, sea carpet squirt, is not only a key marine organism to study morphological ancestral patterns of chordates evolution but it is also of great ecological importance due to its status as a major invasive species. Non-coding RNAs, in particular microRNAs (miRNAs), are important regulatory genes that impact development and environmental adaptation. Beyond miRNAs, not much in known about tunicate ncRNAs. Results: We provide here a comprehensive homology-based annotation of non-coding RNAs in the recently sequenced genome of D. vexillum. To this end we employed a combination of several computational approaches, including blast searches with a wide range of parameters, and secondary structured centered survey with infernal. The resulting candidate set was curated extensively to produce a high-quality ncRNA annotation of the first draft of the D. vexillum genome. It comprises 57 miRNA families, 4 families of ribosomal RNAs, 22 isoacceptor classes of tRNAs (of which more than 72% of loci are pseudogenes), 13 snRNAs, 12 snoRNAs, and 1 other RNA family. Additionally, 21 families of mitochondrial tRNAs and 2 of mitochondrial ribosomal RNAs and 1 long non-coding RNA. Conclusions: The comprehensive annotation of the D. vexillum non-coding RNAs provides a starting point towards a better understanding of the restructuring of the small RNA system in ascidians. Furthermore it provides a valuable research for efforts to establish detailed non-coding RNA annotations for other recently published and recently sequences in tunicate genomes.
19

Autolysis in the development and dispersal of biofilms formed by the marine bacterium Pseudoalteromonas tunicata

Mai-Prochnow, Anne Gerda Erna, Biotechnology & Bio-molecular Sciences, UNSW January 2006 (has links)
The marine bacterium Pseudoalteromonas tunicata produces target-specific inhibitory compounds against bacteria, algae, fungi and invertebrate larvae and is frequently found in association with living surfaces in the marine environment. This study examined the ability of P. tunicata to form biofilms under continuous culture conditions within the laboratory. P. tunicata biofilms exhibited a characteristic architecture consisting of differentiated microcolonies surrounded by water-channels. Interestingly, a repeatable pattern of cell death in the centre of microcolonies was observed. The antibacterial and autolytic protein, AlpP, produced by P. tunicata was found to be involved in this biofilm killing and a
20

Application of modern NMR techniques to structure elucidation of bioactive natural products from tunicates

Sikorska, Justyna 29 August 2012 (has links)
Recent developments in NMR hardware have extended the reach of natural products chemists to structure elucidation of compounds isolated on a nanomolar scale. In parallel with advances in hardware new NMR techniques for structure elucidation have evolved, e.g. quantitative NOEs, residual dipolar couplings (RDCs)and diffusion-ordered spectroscopy (DOSY). The application of recent NMR techniques was utilized in the screening and structural assignment of natural products isolated from a 2004 collection of South African tunicates. Assignment of the planar structures of mandelalides A-D from a new Lissoclinum sp. was feasible only after data acquisition on a 700 MHz magnet equipped with 5 mm ����C cryogenic probe. While relative configuration of the polyketide mandelalides was established after extensive J-coupling and NOE analysis, quantitative ROESY and RDC measurements were also explored before the absolute configuration was accomplished by chemical degradation and comparison with standards. The application of DOSY, a greatly under-appreciated technique in natural products research, led to the identification of new rubrolide analogues, compounds with moderate antibacterial properties from the new species Synoicum globosum. Finally, relative and absolute configuration of new and known unstable amino alcohols from two Pseudodistoma species was based on J-coupling analysis and application of the Mosher method. / Graduation date: 2013

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