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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.
41

Análise da distribuição estratigráfica de Corumbella Werneri HAHN ET AL. 1982 (Formação Tamengo, Ediacarano): Implicações Tafonômicas e Paleoambientais / Analysis of the stratigrahphic distribution of Corumbella werneri Hahn et al. 1982 (Tamengo Formation, Ediacarano): Tafonomic and paleo-environmental implications

Diniz, Cleber Quidute Clemente 30 March 2017 (has links)
Fósseis de Corumbella werneri, cnidário Ediacarano com carapaça biomineralizada são encontrados em pelitos da Formação Tamengo, Grupo Corumbá (MS). Este trabalho teve como objetivos analisar a distribuição estratigráfica de detalhe de Corumbella werneri nessa formação, correlacionar a distribuição estratigráfica às características tafonômicas desses fósseis e estabelecer condições paleoecológicas e paleoambientais, a partir das análises estratigráficas e tafonômicas. Foram analisadas 160 amostras de mão. Para realização da descrição e identificação dos fósseis foram realizadas imagens digitais e em Microscopia Eletrônica de Varredura, medições de características morfológicas e análises químicas através da Espectroscopia de Energia Dispersiva. Para a realização da análise tafonômica básica, foram utilizadas algumas assinaturas tafonômicas como fragmentação, grau de empacotamento e preservação da carapaça. Foi realizada a medição centímetrica das seções pelíticas estudadas e efetuou-se a descrição de fácies sedimentares, estruturas sedimentares, granulometria e conteúdo fossilífero. Foi observado que as ocorrências de Corumbella werneri são na parte pelítica e mais concentradas na base da Formação Tamengo. A ocorrência em determinados níveis estratigráficos onde apresentam abundância de carapaças de C. werneri, pode ser provavelmente, explicada por variações ambientais, como a variação na taxa de sedimentação que eventualmente, proporcionava condições para a preservação das carapaças. A análise estratigráfica de detalhe também permitiu observar as associações de C. werneri com outros organismos e com icnofósseis que também aparecem de forma isolada como estruturas sedimentares circulares de provável origem bioinduzida, estruturas fragmentadas, possível estrutura basal, além de macroalgas, vendotaenídeos e icnofósseis. Com esses registros pode-se dizer que a paleodiversidade da Formação Tamengo é maior do que se pensava anteriormente. Essas associações podem evidenciar correlações paleoecológicas e paleoambientais. Dois grupos tafonômicos distintos de C. werneri foram interpretados. O grupo 1, representado por indivíduos incompletos, apresentariam um ambiente deposicional com aumento da taxa de sedimentação, capaz de preservar o corpo em uma forma mais completa e, em alguns casos, preservar a carapaça de forma tridimensional. O grupo 2, caracterizado por indivíduos fragmentados, apresentam um ambiente com baixa energia e baixa taxa de sedimentação, resultando em um maior tempo de exposição do organismo no substrato, causando a fragmentação das carapaças. Amostras apresentando os dois grupos tafonômicos podem indicar mistura temporal resultando em uma registro intra-habitat no qual várias gerações de uma espécie se preservam em uma mesmo registro fossilífero devido à baixa taxa de sedimentação. A ocorrência de C. werneri exclusivamente nos pelitos, enquanto, Cloudina lucianoi apenas nas camadas de calcário, indica que provavelmente habitaram ambientes diferentes, ou pelo menos o modo e a capacidade de preservação das carapaças deveriam ser distintos. A associação de C. werneri juntamente com macroalgas e a presença de Paraconularia sp. podem indicar condições de águas mais rasas, ainda em zona fótica. Esses novos dados mostram que, talvez, mesmo ocorrendo em pelitos, indicando deposição em águas calmas, seria possível que C. werneri tivesse condições paleoecológicas de habitat desde águas mais rasas, acima do nível de base de ondas de tempestades até mesmo, mais profundas. No entanto, os níveis de ocorrência e de maior abundância de C.werneri devem estar associados a momentos de aumento na taxa de sedimentação e deposição de partículas finas, em substrato abaixo do nível de base de ondas de tempestades. / Fossils of Corumbella werneri, Ediacaran cnidarian with biomineralized carapace are found in pelite of the Tamengo Formation, Corumbá Group (MS). The objective of this work was to analyze a stratigraphic distribution of Corumbella werneri in this Formation, to correlate the stratigraphic distribution to the taphonomic characteristics of fossils and to establish paleoecological and paleoenvironmental conditions, based on the stratigraphic and taphonomic analyzes. A total of 160 hand samples were analyzed. For the description and identification of fossils, digital images and scanning electron microscopy, measurements of morphological characteristics and chemical analyzes using Dispersive Energy Spectroscopy were performed. To perform the basic taphonomic analysis, taphonomic signatures was adopted, such as fragmentation, degree of packing and carapace preservation. A centimeter measurement of the pelitie sections was done and a description of sedimentary facies, sedimentary structures, granulometry and fossiliferous content was made. It was observed that the occurrences of Corumbella werneri are in the pelite part and more concentrated in the base of the Tamengo Formation. The occurrence at certain stratigraphic levels where an abundance of C. werneri carapaces can be explained by environmental variations as a change in the sedimentation rate that eventually, provides conditions for a preservation of the carapaces. The stratigraphic analysis of detail also allowed to observe a correlation of C. werneri with other organisms and with icnofósseis that also appear isolated, like a sedimentary structures in circular form of probable bio-induced origin, fragmented structures, possible basal structure, macroalgae, vendotaenídeos and icnofósseis. With these records, it can be said that the paleodiversity of the Tamengo Formation is greater than previously thought. These associations can show paleoecological and paleoenvironmental correlations. Two distinct taphonomic groups of C. werneri were interpreted. Group 1, represented by incomplete individuals, interpreted a deposited environment with increased sedimentation rate, capable of preserving the body in a more complete form and, in some cases, preserving a three-dimensional shape carapace. Group 2, characterized by having fragmented individuals, presents in an environment with low energy and low sedimentation rate, resulting in a longer exposure time of the organism in the substrate, causing fragmentation of the carapaces. Samples showing the two taphonomic groups results an intra-habitat record when multiple genarations of species preserved in a single fossil record due to the low sedimentation rate. The occurrence of C. werneri exclusively in the pelitics, while, Cloudina lucianoi only in the layers of limestone, indicates that they inhabited different environments, or at least the way and capacity of preservation of the carapaces should be different. An association of C. werneri with macroalgae and a presence of Paraconularia sp. may indicate shallower water conditions, still in the photic zone. These new data show that even C. werneri occurring in pelitcs, indicating deposition in calm waters, it would be possible to have paleoecological conditions of habitat from shallower waters, above the base level of waves of thunderstorms or even deeper. However, C. werneri occurrence levels and greater abundance are associated with growth times in sedimentation rate and fine particle deposition in substrate below the storm level.
42

Componentes químicos do extrato hidroalcoólico de Bunodossoma Caissarum /

Pereira, Gerson Rodrigues Raggi. January 2017 (has links)
Orientador: Wagner Vilegas / Resumo: Organismos marinhos são importantes fontes de novos produtos naturais e compostos bioativos com funções variadas. Entre as principais fontes de novas moléculas esta o filo dos Cnidários, com uma importante contribuição no numero de compostos descritos nos últimos anos. Bunodossoma caissarum é uma espécie de anêmona endêmica do Brasil, cujo perfil químico foi analisado. Para essa análise foram realizados uma extração hidroalcoólica e o isolamento de determinadas moléculas com técnicas cromatográficas. Os compostos isolados foram aqueles que apresentaram absorbância no comprimento de onda no UV em 310 nm e foram identificados a partir de técnicas de espectrometria de massas e ressonância magnética. Entre as substâncias encontradas estão sais piridinicos, núcleos imidazóis, caissarona e a etilglicose, moléculas com importantes papeis fisiológicos / Abstract: Marine organisms are importante sources of new natural products and bioactive compounds with various functions. The phylum Cnidaria is among the main sources of new molecules, with na importante contribution to the number of compounds described in the last years. The anemone species Bunodossoma caissarum is endemic to Brazil and had it's chemical profile analyzed. For the purpose of this analysis were done a hydroalcoolic extraction and the isolation of certain molecules by chomatographic techniques. The isolated compounds were those that displayed absorbance in the 310nm wavelength of the UV spectrum and were identified on the basis of mass spectrometry and magnetic ressonance. Among the substances found are pyridinic salts, imidazole nucleus, caissarone and ethyl glucose, which are molecules with important physiological roles / Mestre
43

On the origin of bilaterality : insights from the study of black corals (Cnidaria : Antipatharia) / L'origine de la bilatéralité : apports de l'étude des coraux noirs (Cnidaria : Antipatharia)

Ferreira Gonçalves, João 28 September 2016 (has links)
L’origine des symétries et des polarités est l’un des thèmes centraux de l’évolution animale. Classiquement considérée comme une innovation propre aux animaux à symétrie bilatérale (Bilateria), la bilatéralité est en fait très largement répandue chez les cnidaires, groupe-frère des Bilateria, principalement au sein de la classe des anthozoaires. La découverte que la voie BMP étai différentiellement exprimé selon l’axe secondaire de N. vectensis a fait que sur la base d’arguments moléculaires certains travaux postulent que la bilatéralité est antérieure à la divergence cnidaires/bilateria (Finnerty et al. 2004, Matus et al. 2006), alors que d’autres chercheurs mettent en avant l’hypothèse d’une convergence sur la base d’arguments anatomiques et phylogénétiques (Manuel 2009). Chez Nematostella les gènes Hox sont différentiellement exprimés dans l’axe directeur et leur expression est contrôlée par la voie BMP. Notre étude avec l’espèce Antipathes caribbeana, un corail noir (Antipatharia) a permet âpre confirmation de ça anatomie a interne a symétrie bilatéral l’étude de l’expression de ces gènes et a discuter l’origine de la bilatéralité. / The origin of body axis is one of the central themes on animal evolution. Usually regarded as an innovation of Bilateria, the bilateral symmetry is broadly distributed in the Anthozoan class of Cnidarians. The molecular basis of this Anthozoan bilaterality have been studied in Nematostella vectensis (Actiniaria), and the discovery that the BMP-pathway was differentially expressed along the secondary axis lead authors to presume that bilaterality was ancestral to the Cnidaria/Bilateria divergence (Finnerty et al. 2004, Matus et al. 2006), while Manuel (2009) preferred a convergence hypothesis based on comparative anatomy and phylogeny. In opposition to Bilateria, HOX genes have recently been shown to be differentially expressed along the secondary axis of N. vectensis. In order to do evolutive inferences from these results it is necessary to study the HOX genes and BMP genes expression patterns in other Anthozoan species. Our study with the antipatharian colonial species Antipathes caribbeana focuses on the detailed anatomy of the polyp, confirming the previously doubtful bilateral organization of its polyps. In order to compare Antipatharian species to N. vectensis, a comparison between the mesenteric formation and symmetries on the different groups of anthozoans is presented, allowing to establish the homology between their secondary axis. The study of the expression of HOX and BMP genes in A. caribbeana shows that they are, as in Nematostella, differentially expressed along the secondary axis. Reinforcing the idea that bilaterality is ancestral to the Cnidaria/Bilateria divergence and that HOX genes have a patterning role on the secondary axis of Anthozoans.
44

Aspects of Nitrogen Metabolism in Symbiotic Cnidarians

Boutilier, Ryan Michael 24 August 2012 (has links)
The pathway of seawater ammonium assimilation and influence of light on amino acid synthesis remain unresolved in cnidarian symbioses. Labeled ammonium (10 μM 15NH4Cl) in seawater was used to trace the pathway of the incorporation into amino acids in host tissue, Zoanthus sp., and zooxanthellae, Symbiodinium microadriaticum. Freshly isolated zooxanthellae were exposed to 20 μM 15NH4Cl with coral homogenate to evaluate the role of host factors on amino acid synthesis. High performance liquid chromatography and mass spectrometry was used to measure percent labeling and concentrations of amino acids. In zooxanthellae, ammonium was assimilated into glutamine likely via glutamine synthetase and into glutamate via glutamine 2-oxoglutarate amidotransferase. Interrupting photosynthesis with DCMU did not inhibit glutamine and tryptophan synthesis however reduced the 15N-enrichment of glutamate, aspartate, and ornithine in zooxanthellae, as well as arginine, ornithine, and lysine in host tissue. Coral homogenate had little effect on the 15N-enrichment of glutamine, aspartate, and alanine in freshly isolated zooxanthellae. Evidence is presented to support the uptake of ammonium ions and data shows that glutamine and not glutamate is translocated to the coral host.
45

Niche Modelling : a comparison between modelling methods best applied for Cnidaria niche dispersion studies /

Lima, Alessandra Vallim January 2017 (has links)
Orientador: Sérgio Nascimento Stampar / Abstract: Recently, ecological niche modelling has been receiving more attention in several areas in biology, due to the evolution of personal computers, and the increasing availability of data used in modelling. The results obtained can be used in preventive actions such as species management and invasive species distribution. Since its increasing popularity, several algorithms are available and undergoing tests regarding their performance towards different phylum. Marine invertebrates, more specifically cnidarians, present few studies on this field, and should receive closer attention in the next years due to worldwide increases in jellyfish population (blooms), and bleaching in almost every known shallow water coral reef. Because of this gap of information, we chose this still poor studied group to compare three algorithms. We used MAXENT, GARP and AquaMaps in its desktop form and selected them based on other studies comparing algorithms. Our aim was to, based on different organisms of the phylum Cnidaria, Lychnorhiza lucerna, Chrysaora lactea, Phyllorhiza punctata, Tamoya haplonema, Ceriantheomorphe brasiliensis and Mussismilia hispida, compare those algorithms and examine which one performed the best. Our results shown that MAXENT outperformed the other algorithms both regarding de Area Under the ROC Curve (AUC) and the map distribution. GARP show varying results with generalized maps and AquaMaps was the least accurate of them. Our results are similar to those found in other pape... (Complete abstract click electronic access below) / Resumo: Nas ultimas décadas, modelagem de nicho ecológico vem recebendo maior atenção em diversas áreas da biologia devido a evolução dos computadores pessoais e aumento dos dados disponíveis utilizados para a modelagem. Os resultados obtidos podem ser utilizados em ações preventivas, tais quais manejo de espécie e acompanhamento da distribuição de espécies invasoras. Desde o aumento dessa popularidade, diversos algoritmos estão disponíveis e testes estão em andamento para averiguar suas performances em relação a diferentes filos. Invertebrados marinhos, mais especificamente cnidários, apresentam poucos estudos nesse ramo, devendo receber mais atenção nos próximos anos devido ao aumento global das populações de aguas vivas (blooms), e branqueamento em quase todos os recifes de corais. Devido a essa lacuna em informação, este grupo foi escolhido para comparar três algoritmos. Utilizamos o MAXENT, GARP e AquaMaps em suas formas de desktop e os selecionamos baseado em outros estudos comparando algoritmos. Utilizamos diferentes organismos do filo cnidária, Lychnorhiza lucerna, Chrysaora lactea, Phyllorhiza punctata, Tamoya haplonema, Ceriantheomorphe brasiliensis e Mussismilia hispida, para comparar os algoritmos e averiguar qual demonstrou melhor performance. Nossos resultados mostram que o MAXENT superou os outros algoritmos tanto com relação a Área Sob a Curva ROC (AUC), quanto com relação aos mapas de distribuição. O GARP apresentou resultados variados com mapas generalizados e AquaM... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
46

Análise morfológica e filogenética do gênero Lensia (Cnidaria, Hydrozoa, Siphonophora)

Nishiyama, Eric Yukihiro January 2016 (has links)
Orientador: Prof. Dr. Otto Müller Patrão de Oliveira / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Evolução e Diversidade, 2016. / Os sifonóforos são um grupo de hidrozoários (Cnidaria: Medusozoa) de grande importancia no ambiente pelagial marinho. Apesar disso, estudos sobre a sistemática desses organismos são escassos na literatura. Pouco se sabe sobre as relações filogenéticas entre os táxons superiores do grupo, e pouco progresso foi feito até o momento para o gênero Lensia. O presente estudo teve como objetivos realizar uma minuciosa análise morfológica do nectóforo anterior dos diferentes morfotipos do gênero Lensia, provenientes de duas campanhas oceanográficas, e realizar a análise filogenética desses morfotipos, com base nos dados morfológicos obtidos. O material analisado foi proveniente de duas campanhas oceanográficas (FINEP III e Projeto Habitats), realizadas ao longo da costa sudeste do Brasil. Ao todo foram analisados 61 espécimes e foram identificadas 15espécies de Lensia. Os espécimes foram fotografados com um estereomicroscópio com camera digital acoplada. Em seguida, foram identificados, descritos, esquematizados e medidos. Foi elaborada uma chave de identificação das espécies analisadas. Foram listados 22 caracteres do nectóforo anterior de Lensia, que foram codificados em uma matriz de dados. Foram utilizadas duas espécies do gênero Diphyes e uma espécies do gênero Muggiaea, como grupos externos. A análise filogenética foi feita com o software TNT, e as árvores mais parcimoniosas foram buscadas usando pesagem implícita (k variando de 2 a 6). A análise resultou em quatro árvores mais parcimoniosas. A espécie L. leloupi é o grupo-irmão das espécies estudadas. As espécies de Lensia formaram um clado sustentado pelo hidroécio mediando até um quarto do comprimento do nectosaco. / Siphonophores are a group of hydrozoans (Cnidaria: Medusozoa) of great importance in the marine pelagic environment. Despite that, studies about the systematics of these organisms are scarce in the literature. Little is known about the phylogenetic relationships between the group's superior taxa, and little progress has been made until the moment for the genus Lensia. The objectives of the present study were to conduct a detailed morphological study of different morphotypes of the genus Lensia, obtained from two oceanographic campaigns, and perform a phylogenetic analysis of these morphotypes, based on the morphological data obtained. The analyzed material was collected by two oceanographic campaigns (FINEP III and Habitats Project), made throughout the southeastern Brazilian coast. A total of 61 specimens were analyzed and 15 species of Lensia were identified. Specimens were photographed using a stereomicroscope with digital camera attached. Posteriorly, the identification, morphological descriptions, elaboration of schemes, and measurements of specimens were performed. An identification key of the analyzed species was elaborated. Twenty two characters of the anterior nectophore of Lensia were listed, and codified in a data matrix. Two species of the genus Diphyes and one species of the genus Muggiaea were used as outgroups. A phylogenetic hypothesis, based on the morphological data, was inferred using the TNT software, and the shortest trees were searched using implied weighting (k varying from 2 to 6). The analysis resulted in four most parsimonious trees. The species L. leloupi is the sister group to all studied species. The species of Lensia formed a clade sustained by the hydroecium measuring up to onequarter the height of the nectosac.
47

Positional cloning of the allorecognition gene alr1 in the cnidarian Hydractinia symbiolongicarpus

Rosa, Sabrina 08 March 2010 (has links)
Allorecognition, defined as the ability to discriminate between self and non-self, is ubiquitous to colonial metazoans and widespread in aclonal taxa. Invertebrate allorecognition phenomena are of broad interest and have long captured the attention of geneticists by virtue of the allotypic diversity they display, marine ecologists by virtue of their control of effector mechanisms determining the outcome of intraspecific competition, evolutionary biologists by virtue of their regulation of the level at which selection acts, and immunologists by virtue of their resemblance to the allogeneic interactions that characterize pregnancy and transplantation in vertebrates. Diverse histocompatibility modes have been described in the jawed vertebrates, protochordates, and cnidarians, which are to date the only three taxa for which a genetic model to study allorecognition has been developed. Outside of the MHC-based histocompatibility of vertebrates, allorecognition determinants have been recognized in only two invertebrates. In the tunicate Botryllus, two genes involved in the histocompatibility response were characterized, FuHc and fester. In Hydractinia, the loci controlling allorecognition, alr1 and alr2, were mapped to a single chromosomal region, the allorecognition complex, and alr2 was recently identified as a polymorphic immunoglobulin superfamily (IgSF) receptor. In this study, the identification of the second Hydractinia allodeterminant, alr1, was undertaken. Chapter I briefly reviews prominent allorecognition model organisms and details the phenomenon in the model organism, Hydractinia symbiolongicarpus studied here. Chapter II describes the isolation of a 300.8 kb alr1-containing chromosomal interval by positional cloning. The analysis of that interval for its gene content and the determination of a primary alr1 candidate, CDS4, are described in Chapter III. Chapter III also reveals the existence of a complex of IgSF-like genes, to which belongs CDS4. CDS4, a novel polymorphic IgSF receptor that encodes a type I transmembrane protein with two hypervariable immunoglobulin-like extracellular domains, was confirmed to be the alr1 allodeterminant in Chapter IV, based on the investigation of natural polymorphism. CDS4 allele sequences were found to largely predict the outcome of allorecognition responses within and between laboratory lines and wild-type colonies, confirming the identity of CDS4 as the classically defined locus alr1. / Doctorat en sciences, Spécialisation biologie moléculaire / info:eu-repo/semantics/nonPublished
48

Relative involvement of different cnidocyte supporting cell complexes and extracellular calcium in prey capture of sea anemone, Haliplanella luciae

Mc Auley, Virginia Nenna 01 January 2001 (has links)
No description available.
49

Epigenetic transcriptional memory of thermal stress in the cnidarian model system Aiptasia

Dix, Mascha 05 1900 (has links)
Ocean warming is leading to increased occurrence of coral mass bleaching events, threatening the persistence of these ecosystems and the communities that rely on them. While reef recovery is possible, conservation approaches based purely on transplantation/coral-gardening will not suffice to maintain these ecosystems over the projected environmental changes. Assisted evolution approaches aim to boost acclimatization and adaptation processes. A potential approach could be to harness the naturally occurring mechanism of environmental memory that has been observed in corals and other organisms, where an organism remembers a priming stress event to allow a faster/stronger response when the stress re-occurs. In this thesis I aimed to investigate whether this mechanism exists and how it is regulated on a molecular level in the sea anemone Aiptasia. Aiptasia were primed to heat stress by exposing them to 32 °C water for several years, or for one week. After a recovery period of one week at 25 °C, a naïve and the primed treatments were exposed to lethal thermal stress at 34 °C for three days. Primed treatments performed better than the naïve treatment in survival, photosynthetic efficiency and symbiont density for two days, after which the priming advantage was lost. The difference between the primed treatments indicated that the priming dose may affect priming success. There were clear indications of an epigenetic transcriptional memory mechanism on a transcriptional level. I observed a pronounced difference between control and heat-stressed treatments, indicating that transcription returned to near baseline expression after cessation of the priming exposure. The functional categories of differentially expressed genes in heat stress relative to control were similar between naïve and primed treatments, with the main difference observed in a stronger up- and downregulation of stress response genes in the long-term primed treatment. I optimized a chromatin immunoprecipitation protocol for use with Aiptasia by adjusting fixation, sonication and immunoprecipitation conditions. The enrichment of H3K4me2/me3 and poised RNA Pol II in the promoters of stress response genes will be investigated next to elucidate the mechanism of the observed epigenetic transcriptional memory in Aiptasia, and to ultimately inform conservation strategies for coral reefs globally.
50

SCALING OF INDIVIDUAL BEHAVIOR TO GROUP DYNAMICS: THEORETICAL AND EXPERIMENTAL CONCERNS WITH REGARD TO POLYP AND CLONE BEHAVIOR IN <i>ANTHOPLEURA ELEGANTISSIMA</i>

D'Orazio, Anthony Emidio 22 June 2012 (has links)
No description available.

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