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Tenbaum, Stephan. "Characterization of alien isoforms in vertebrates Charakterisierung von Alien-Isoformen in Vertebraten /." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965239225.
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Byun, S. Ashley. "Quaternary biogeography of western North America insights from mtDNA phylogeography of endemic vertebrates from Haida Gwaii /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ37334.pdf.
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Santos, Santos Javier H. "Ecomorphological discrimination of vertebrate sister species with recent phylogenetic divergence using novel non-destructive morphometric methods = Discriminación ecomorfológica de especies hermanas de vertebrados con divergencia filogenética reciente utilizando nuevos métodos morfométricos no-destructivos." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/666609.
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The thesis "Ecomorphological discrimination of vertebrate sister species with recent phylogenetic divergence using novel non-destructive morphometric methods” compares morphological evolution during syntopic adaptive radiation between two vertebrate classes: the model African cichlid fish and the non-model Malagasy mantellid frogs. In Section I the ontogenetic body shape development of two Lake Victoria haplochromine cichlid sister species (Haplochromis fischeri and H. piceatus) and their non-natural hybrid is described by means of landmark-based Geometric Morphometrics. Chapter 1 relates divergent shape changes in the parental species to their respective trophic specializations and discloses associated shape variation linked to their respective locomotor specializations along the benthic-limnetic axis. Chapter 2 observes their hybrid to display a mosaic of parental and unique morphological features and discusses the influence of hybridization in the radiation of East African cichlids. In Section II computed-tomography (CT) techniques are used to study the musculoskeletal anatomy of mantellid frogs, genus Blommersia. Chapter 3 provides the ecological, morphological, and phylogenetic description of two new species of Blommersia (B. alexi and B. nataliae) found on the Comorian island of Mayotte thought to have evolved in sympatry and to be undergoing opposite processes of gigantism and nanism, respectively, in relation to their most recent common ancestor. Chapter 4 provides the first complete skeletal description for any mantellid species, B. alexi, and reveals genus-specific osteological features that are predicted to be implicated in their locomotion and unique reproductive behavior. Chapter 5 presents a custom soft-tissue contrast staining technique used prior to CT-scanning and applies the recently developed featureless Geometric Morphometric technique of Generalized Procrustes Surface Analysis to compare pelvic shape across seven species of the genus Blommersia, relating observed patterns of shape variation to their phylogenetic relationships and pelvic muscular architecture. In Section III the biomechanics of anuran locomotion are evaluated. Chapter 6 explores biomechanical performance during jumping and swimming locomotion in the wood frog (Rana sylvatica), putting special emphasis on the hindleg musculature implicated in thrust production during both locomotor modes, and reveals incredible physiological resilience as reflected by their relatively unaltered biomechanical performance before and after freezing. Overall, cichlid fish morphological evolution appears to be influenced to a larger degree by trophic ecological pressures, whereas in mantellid frogs it is body size variation and locomotor performance that condition species' divergence.La tesis "Discriminación ecomorfológica de especies hermanas de vertebradas con divergencia filogenética reciente utilizando nuevos métodos morfométricos no destructivos" compara la evolución morfológica durante la radiación adaptativa sintópica entre dos clases de vertebrados: los peces cíclidos africanos modelo y las ranas mantélidas malgaches no modelo. En la Sección I, el desarrollo ontogenético de la forma del cuerpo de dos especies hermanas de cíclidos haplochrominos del Lago Victoria (Haplochromis fischeri y H. piceatus) y de su híbrido no-natural se describe mediante métodos de Geometría Morfométrica basado en landmarks. El Capítulo 1 relaciona los cambios divergentes en forma entre las especies parentales a sus respectivas especializaciones tróficas y revela variación en forma asociada a sus respectivas especializaciones locomotoras según el eje bentónico-limnético. El capítulo 2 muestra que su híbrido presenta un mosaico de características morfológicas parentales y únicas, y discute la influencia de la hibridación en la radiación de los cíclidos africanos. En la Sección II, se utilizan técnicas de tomografía computarizada (CT) para estudiar la anatomía musculo-esquelética de las ranas mantélidas, género Blommersia. El Capítulo 3 proporciona la descripción ecológica, morfológica, y filogenética de dos nuevas especies de Blommersia (B. alexi y B. nataliae) halladas en la isla comorana de Mayotte, que se cree evolucionaron en simpatría y que están sufriendo procesos opuestos de gigantismo y nanismo, respectivamente, en relación a su ancestro común más reciente. El Capítulo 4 proporciona la primera descripción esquelética completa para cualquier especie de mantélido, B. alexi, y revela características osteológicas específicas del género que se predice que están implicadas en su locomoción y comportamiento reproductivo único. El Capítulo 5 presenta una técnica personalizada de tinción de contraste de tejidos blandos para utilización antes de la CT y aplica la técnica recientemente desarrollada de Geometría Morfométrica para estructuras lisas llamada Generalized Procrustes Surface Analysis para comparar la forma pélvica entre siete especies del género Blommersia, de esta forma relacionando los patrones observados de variación en forma con sus relaciones filogenéticas y arquitectura muscular pélvica. En la Sección III, se evalúa la biomecánica en la locomoción de los anuros. El capítulo 6 explora el rendimiento biomecánico durante la locomoción de salto y natación en la Rana sylvatica, poniendo especial énfasis en la musculatura de la pata trasera implicada en la producción de empuje durante ambos modos locomotores, y revela una increíble resistencia fisiológica reflejada por su rendimiento biomecánico relativamente inalterado antes y después de ser congelado En general, la evolución morfológica en los peces cíclidos parece estar influenciada en mayor medida por las presiones ecológicas tróficas, mientras que en las ranas mantélidas es la variación del tamaño corporal y el rendimiento locomotor lo que condiciona la divergencia de las especies.
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Chew, Guo-Liang. "Non-Canonical Translation in Vertebrates." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467487.
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Translation is a key process during gene expression: to produce proteins, ribosomes translate the coding sequences of mRNAs. However, vertebrate genomes contain more translation potential than these annotated coding sequences: translation has been detected in many non-coding RNAs and in the non-coding regions of mRNAs. To understand the role of such translation in vertebrates, I investigated: 1) the distribution of translation in vertebrate long non-coding RNAs, and 2) the effects of translation in the 5’ leaders of vertebrate mRNAs.
To quantify and localize translation in a genome-wide manner, we produced and analyzed ribosome profiling data in zebrafish, and analyzed ribosome profiling data produced by others. The nucleotide resolution afforded by ribosome profiling allows localization of translation to individual ORFs within a transcript, while its quantitative nature enables measurement of how much translation occurs within individual ORFs.
We combined ribosome profiling with a machine-learning approach to classify lncRNAs during zebrafish development and in mouse ES cells. We found that dozens of proposed lncRNAs are protein-coding contaminants and that many lncRNAs have ribosome profiles that resemble that of the 5’ leaders of coding mRNAs. These results clarify the annotation of lncRNAs and suggest a potential role for translation in lncRNA regulation.
Because much of the translation in non-coding regions of mRNAs occurs within uORFs, we further examined the effects of their translation on the cognate gene expression. While much is known about the repression of individual genes by their uORFs, how uORF repressiveness varies within a genome and what underlies this variation had not been characterized. To address these questions, we analyzed transcript sequences and ribosome profiling data from human, mouse and zebrafish.
Linear modeling revealed that sequence features at both uORFs and coding sequences contribute similarly and substantially toward modulating uORF repressiveness and coding sequence translational efficiency. Strikingly, uORF sequence features are conserved in mammals, and mediate the conservation of uORF repressiveness in vertebrates. uORFs are depleted near coding sequences and have initiation contexts that diminish their translation. These observations suggest that the prevalence of vertebrate uORFs may be explained by their functional conservation as weak repressors of coding sequence translation.Biology, Molecular and Cellular
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Molnar, Julia Louise. "The biomechanics of vertebrae over evolutionary transitions between water and land: examples from early Tetrapoda and Crocodylomorpha." Thesis, Royal Veterinary College (University of London), 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618323.
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With the transition from water to land in early tetrapods, and with transitions to secondarily aquatic habits in numerous tetrapod lineages, the functions of the vertebral column were transformed. Morphological changes in the vertebral column are a major mechanism by which vertebrates accommodate changes in locomotor forces. Although morphometric measurements from vertebrae have been correlated with axial mechanics and locomotor behaviour in numerous extant taxa, few studies have sought to test or apply these principles in non-mammalian tetrapods. In my thesis, I reconstructed the vertebral mechanics of fossil taxa that represent intermediate stages in water/land transitions of their lineages. Study taxa were the basal tetrapod Pederpes finneyae, which is one of the earliest known tetrapods to show indications of terrestrial adaptation, and three extinct crocodylomorphs, Terrestrisuchus, Protosuchus, and Pelagosaurus, which span the spectrum from fully terrestrial to primarily aquatic. I used a combination of morphometric measurements and 3D virtual models of bone morphology to estimate intervertebral joint stiffness and range of motion. For comparison, I also reconstructed the vertebral mechanics of four related extant taxa. Correlations between vertebral morphometrics and axial stiffness were statistically tested in (cadaveric) modem crocodylians, and I validated my methodology by comparing my results with data from extant taxa. My results reveal similarities and differences between the two lineages. Intervertebral joint compliance and range of motion tended to decrease with adaptation for terrestrial locomotion, as expected, but this trend seems to have reversed in later forms. Additionally, vertebral mechanics may have been largely controlled by different structural mechanisms in different lineages. The relationship between biomechanics of vertebrae and environment appears to be more complex than previously supposed. However, approaches that combine experimental measurements from extant animals, thorough analysis of fossil morphology, and explicit phylogenetic considerations have the potential to greatly improve locomotor reconstructions of extinct taxa.
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Giles, Sam. "How to build a bony vertebrate in evolutionary time." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:1df4ba59-c709-4e3c-99c0-b49d1132743f.
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Jawed vertebrates (gnathostomes) account for over 99% of living vertebrate diversity, with origins that stretch back nearly half a billion years, and comprise two groups: Osteichthyes (fishes and land-dwelling vertebrates) and Chondrichthyes (sharks, rays and chimaeras). Osteichthyans are the dominant clade, with at least 60,000 species approximately evenly divided between two clades: the Actinopterygii and the Sarcopterygii. However, our understanding of early osteichthyan evolution is skewed in favour of sarcopterygians, leaving the origin of nearly half of all vertebrate diversity critically understudied. Furthermore, recent upheavals in the early gnathostome tree have destabilised relationships amongst fossil taxa and eroded our understanding of primitive anatomical conditions of key groups. Central to understanding early gnathostome evolution is the braincase, an anatomically complex structure that provides a wealth of morphological characters. However, braincases rarely fossilise, and their position inside the skull makes them difficult to attain. X-ray tomography allows a comprehensive description of the internal and external anatomy of fossils, including the braincase. This thesis sets out to target phylogenetically pivotal taxa and incorporate new anatomical data in building up a picture of character evolution in early jawed vertebrates. In particular, I target the gnathostome stem, describing a new taxon that helps bridge the morphological gap between placoderms and crown gnathostomes, allowing a more comprehensive understanding of both dermal and endoskeletal evolution. I also focus on early actinopterygians, describing the endoskeleton of the first members of the group in order to understand primitive anatomical conditions. I then investigate actinopterygian braincase anatomy in the context of a revised phylogenetic analysis, illuminating the early evolution of the actinopterygians. Finally, I present a synthetic review of braincase anatomy across the early gnathostome tree. These results provide a more accurate picture of braincase evolution across gnathostomes and actinopterygians, clarifying our understanding of their evolution while revealing new information about when key innovations arose in the brains of the very first ray-finned fishes.
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Konrad, Jonathan Paul. "Telomere replication and regulation in vertebrates." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624117.
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Curran, Anthony A. "A Multimedia Atlas of Dissection for Comparative Anatomy of the Vertebrates." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc2224/.
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Traditional methods of teaching the laboratory course for Comparative Anatomy of the Vertebrates could be improved by applying current computer technology to construct an interactive, multimedial atlas of dissection. Five specimens used in comparative anatomy courses at most institutions were chosen as representative members of the Phylum Chordata: amphioxus, lamprey, dogfish shark, mud puppy, and cat. Specimens were dissected according to the modified method of Wischnitzer, 1993, and each stage was photographed with a Kodak DC120 digital zoom camera. These images were processed on a Power Macintosh 7600 computer with Adobe Photoshop v. 5.0. The atlas was constructed from these images using Macromedia Authorware v. 4.0.3. Each image contains a series of interactive objects that display a highlight and descriptive text as the cursor passes over each object.
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Edmunds, C. E. "Temporal control of translesion synthesis in vertebrates." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598768.
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Translesion synthesis is a potentially mutagenic method of damage encountered by replication forks in the DNA template. The high-fidelity replicative polymerase can be replaced by a translesion polymerase which is better able to accommodate damaged or mismatched bases in its active site. Mutation occurs due to the non- or mis-instructional nature of the lesion and due to the naturally lower fidelity of these specialised polymerases. In the budding yeast Saccharomyces cerevisiae translesion synthesis is controlled by ubiquitination of the DNA sliding clamp PCNA, but in vertebrates the situation is more complex; PCNA ubiquitination is not epistatic to at least two translesion polymerases (Rev1 and DNA polymerase κ). Translesion synthesis can take place either at the replication fork, maintaining replication fork integrity, or replication can restart downstream of the lesion leaving a postreplicative gap that must be filled in later. I have examined these two scenarios separately, and found that they have different genetic requirements. By using stretched DNA fibres to monitor ongoing replication forks. I have shown that translesion synthesis at the replication fork requires Rev1 but not PCNA ubiquitination. This role of Rev1 in ‘on-the-fly’ translesion synthesis is mediated by its C-terminus, which contains the translesion polymerase interaction domain and the PCNA interaction domain. PCNA ubiquitination is, however, necessary for translesion synthesis at postreplicative gaps. Furthermore, two-hybrid analysis and in vitro pulldowns have shown that Rev1 can interact directly with PCNA without ubiquitination of PCNA, suggesting that it can act as an alternative adaptor between PCNA and the other translesion polymerases.
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Bird, Steve. "Molecular evolution of interleukin-1β within vertebrates." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395251.
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The principal aim of this investigation is to sequence IL-1β within a number of non-mammalian vertebrates, in order to establish a better idea of when this molecule arose within vertebrate evolution. IL-1β is a good candidate to study as it has been shown to play many important roles within the immune and neuroendocrine system of mammals. Using an homology cloning approach IL-1β has been sequenced from a cartilaginous fish (Scyliorhinus caniculus), a number of bony fish (Pleuronectes platessa, Dicentrarchus labrax and Carassius auratus), an amphibian (Xenopus laevis) and a primitive mammal (Ornithorhynchus anatinus). All nucleotide sequences are found to contain differing numbers of mRNA instability motifs, characteristic of genes which code for inflammatory mediators. All amino acid sequences contain the IL-1 family signature and show highest conservation in the regions which are predicted to form the 12β-sheets, important for the folding of the active molecules. The O. anatinus IL-1β contains an ICE cut site which is in keeping with all other mammalian sequences, whereas none of the other sequences contain this cut site as found in all non-mammalian vertebrates to date. Like all other IL-1β molecules they contain no signal peptides, indicating that these molecules are not secreted through the classical golgi/endoplasmic reticulum route. Within C. auratus two different IL-1β genes were sequenced, IL-1β and IL-1β2. The second gene contained a different IL-1 family signature to the first and also had regions of coding sequence missing, a region at the 5- end, which is presumed to be due to the loss of an exon and two other regions, one which is 3 bp and the other 12 bp long. The second gene also showed differences in the 3' UTR sequence and position of its stop codon when compared to the first gene.
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Churchill, Thomas Allen Carleton University Dissertation Biology. "Metabolic biochemistry of freeze tolerance in vertebrates." Ottawa, 1992.
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Leigh-Brown, Sarah Catherine. "The evolution of gene regulation in vertebrates." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610564.
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Hedrick, Michael Scott. "Aspects of cardiovascular oxygen transport in vertebrates." PDXScholar, 1985. https://pdxscholar.library.pdx.edu/open_access_etds/3404.
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The hematological and rheological characteristics of blood from a number of vertebrates was compared to assess possible species differences in blood viscosity that may influence cardiovascular oxygen transport. Nucleated red blood cells (RBCs) were more viscous (measured by cone-plate viscometry) in comparison with enucleate (mammalian) RBCs at hematocrits greater than 40% when measured at equivalent temperatures. The lower viscosity of enucleate RBCs is attributed to an enhanced deformability of enucleate cells in comparison to nucleated cells.
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Fritz, Susanne. "Comparative analyses of extinction risk in vertebrates." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/5275.
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Measures of current extinction risk imply that a high proportion of the world’s species are threatened with global extinction in the near future, stressing the need for thorough understanding of extinction processes. In this thesis, I investigate three aspects of current global species extinction risk, using novel phylogenetic and spatially-explicit comparative methods. First, I develop a new measure of the phylogenetic-signal strength in extinction risk, and use it to show that the nonrandomness in global mammalian extinction risk differs with threatening processes. These results imply that the biological traits which increase species’ susceptibility depend on the anthropogenic threat experienced. Secondly, I investigate the focus of current extinction risk, both spatially and in terms of biological traits increasing risk. I model regional extinction-risk correlates for mammals across the globe, finding strong geographical variation in the influence of biological traits on risk, and in trait interactions with anthropogenic impacts. I also compare biological and anthropogenic correlates of global extinction risk across and within mammals, birds and frogs. Results from this large-scale comparative study further confirm the strong heterogeneity of extinction processes, with taxon-specific traits playing a relatively large role in determining species’ fates. Finally, I estimate possible impacts of current extinction risk using three measures of global mammalian diversity: species richness, phylogenetic diversity and functional diversity. My results show that selective losses of large species will deplete functional variety in mammals, especially in the tropics. Loss of functional diversity is much higher than expected under random species loss, and there is low congruence with losses of species richness and phylogenetic diversity. The selectivity of current extinction risk means that we stand to lose a very biased sample of global diversity, with potentially severe consequences for ecosystem functioning.
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Freedman, Kim. "Aspects of the taphonomy of jawless vertebrates." Thesis, University of Leicester, 1999. http://hdl.handle.net/2381/30433.
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Consideration of taphonomy enhances our understanding of jawless vertebrate history. The hagfish Myxine glutinosa was decayed in a variety of conditions. In all cases, anatomical structures generally regarded as highly decay-resistant degraded before others presumed less so. Even observed decay-resistance, moreover, may not be a reliable criterion for the identification of fossil features. When M. glutinosa carcasses experience taphonomic events that promote exceptional preservation, however, their appearance provides links between features of fossils and anatomical parts of the living animal. W-shaped muscle blocks, for example, can become irregular, Z-, or V-shaped during decay, an observation relevant to interpretations of conodonts with Pikaia gracilens. On the basis of the response of M. glutinosa to conditions of exceptional preservation, hagfish fossilization is predicted to be rare and biased towards young individuals; this prediction conforms to their observed fossil record. The taphonomy of M. glutinosa carcasses depends heavily upon anatomical factors particular to hagfishes, so these results cannot be readily extended to explain bias in the histories of other vertebrates. An approach emphasizing taphonomy and incorporating three-dimensional modelling allow features of the problematic fossil taxon Jamoytius kerwoodi to be identified more rigorously. Jamoytius is redescribed as a jawless vertebrate with W-shaped phosphatic scales, ten or more pairs of branchial openings, optic capsules, a subterminal mouth, a terminal nasohypophysial opening, and paired ventrolateral appendages. Cladistic analyses, with the characters of Jamoytius coded as proposed in this study, place it as a sister-taxon to the anaspids. The orientations at which the feeding apparatuses of the conodont Promissum pulchrum collapsed relative to the sea floor were determined by comparing specimens to a three-dimensional model of the apparatus. Measurements of these collapse orientations provide no evidence that the Soom Shale had a soupy substrate when Promissum was deposited.
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Ramm, Cíntia Barbosa. "Contaminação por metais nas capivaras Hydrochaeris hydrochaeris no Sul do Brasil." reponame:Repositório Institucional da FURG, 2015. http://repositorio.furg.br/handle/1/6051.
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A capivara Hydrochaeris hydrochaeris é um roedor de grande porte e semiaquático. A espécie ocorre em vários ambientes, podendo ocorrer em regiões com alto grau de influencia antrópica. A BR-471 que corta longitudinalmente a ESEC Taim, causa impacto localmente na região, por estar ocasionando prejuízos à fauna e a flora, em função dos atropelamentos de capivaras ao longo da reserva. Nesta região também vem sendo utilizados pesticidas e herbicidas, que podem estar contribuindo com a presença de metais. Estes metais podem se depositar no sedimento e na coluna d’água afetando direta ou indiretamente os organismos. No entanto as capivaras estão sujeitas aos efeitos da bioacumulação destes possíveis contaminantes, adquiridos através da ingestão de plantas contaminadas por metais. Com isso, o objetivo desse trabalho é avaliar os níveis de contaminação por metais pesados em tecidos de capivaras (Hydrochaeris hydrochaeris) mortas por atropelamentos na Br-471 Sul do Rio Grande do Sul. Para determinar as concentrações de metais (Ag, Cd, Cu, Pb, e Zn) em diferentes tecidos (fígado, rim, gordura, músculo) pelo e conteúdo estomacal de capivara, foram realizadas coletas mensais ao longo de um ano. As amostragens dos animais mortos serão feitas através de necropsia, as amostras e serão acondicionadas em tubos de plástico e posteriormente congeladas. Após, essas amostras serão pesadas, secas e digeridas em ácido nítrico e diluídas em água MilliQ. As concentrações de Ag, Cd, Cu, Pb, e Zn serão determinados por espectrofotometria de absorção atômica. Os dados serão expressos como média ± erro padrão. As médias dos metais dos tecidos de machos e fêmeas serão comparadas através de Analise de Variância de duas vias (ANOVA), seguida de teste a posterior de Tukey, com significância de 5%. Os resultados, demonstraram que a concentração de prata foi menor na primavera em relação às outras estações do ano nas amostras (P<0,05), não houve variação significativa (P< 0,05) na concentração de cádmio nas amostras, a concentração de chumbo na primavera foi maior em todas as amostras (P< 0,05), a concentração de cobre no inverno e no outono foi significativamente menor que o verão e a primavera (p< 0,05), a concentração de zinco não teve variação ao longo do ano (P< 0,05). O Cd, Ag e o Pb não tiveram variação significativa ao longo do ano no sedimento (P<0,05), já o Cu foi presente no sedimento na primavera, e o Zn foi maior no outono e inverno. (P<0,05). Os resultados deste trabalho demonstraram que as capivaras estão contaminadas por metais não essenciais na Estação Ecológica do Taim. Além disso, podemos sugerir a utilização de pelo para o monitoramento de contaminação da capivara por metais.
The capybara Hydrochaeris Hydrochaeris is a rodent large and semiaquático. The species occurs in various environments and can occur in regions with high anthropogenic influences. The BR- 471 that cuts along the ESEC Taim, impacts locally in the region, to be causing damage to fauna and flora, according to the roadkill capybaras along the reservation. This region has also been used herbicides and pesticides that may be contributing to the presence of metals. These metals can be deposited in the sediment and the water column affecting directly or indirectly the bodies. However capybaras are subject to the effects of bioaccumulation of these possible contaminants, acquired through eating plants contaminated by metals. Thus, the aim of this study is to assess the levels of heavy metal contamination in tissue capybaras (Hydrochoerus hydrochaeris) killed by being run over in the BR-471 South Rio Grande do Sul. To determine the concentrations of metals (Ag, Cd, Cu , Pb, and Zn) in different tissues (liver, kidney, fat, muscle) and the stomach contents of capybara, monthly samples were taken over a year. Samples of the dead animals will be made through autopsy, samples and will be placed in plastic tubes and subsequently frozen. After these samples are weighed, dried and digested in nitric acid and diluted in MilliQ water. The Ag concentrations of Cd, Cu, Pb, and Zn are determined by atomic absorption spectrophotometry. The data are expressed as mean ± standard error. The means of the metals of male and female tissues will be compared by analysis of two-way variance (ANOVA) followed by Tukey test later, with 5% significance. The results showed that the silver concentration was lower in the spring relative to the other seasons in samples (P <0.05), there was no significant difference (P <0.05) in cadmium concentration in the samples, the concentration lead spring was higher in all samples (P <0.05), the concentration of copper in the winter and autumn was significantly lower than the spring and summer (p <0.05), the concentration of zinc was not variation throughout the year (P <0.05). Cd, Ag and Pb have not changed throughout the year in the sediment (P <0.05), whereas the Cu was present in the sediment in the spring, and Zn was higher in autumn and winter. (P <0.05). These results demonstrated that capybaras are contaminated by non-essential metals in the Taim Ecological Station. In addition, we suggest the use of at for contamination monitoring of the capybara for metals.
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Baverstock, P. R. "Studies in the adaptation and evolution of the Australasian fauna : a collection /." Title page, introduction and index only, 1987. http://web4.library.adelaide.edu.au/theses/09SD/09sdb353.pdf.
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Thesis (D. Sc.)--University of Adelaide, 1988.Collection of previously published articles. Includes Allozyme electrophoresis / B.J. Richardson, P.R. Baverstock and M. Adams (1986). Includes bibliographical references.
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Natus, Inar Rosmayati. "Biodiversity and endemic centres of Indonesian terrestrial vertebrates." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=977856852.
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Salaneck, Erik. "Molecular Evolution of Neuropeptide Y Receptors in Vertebrates." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-4988-3/.
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Koons, David Nelson Grand James Barry. "Transient population dynamics and population momentum in vertebrates." Auburn, Ala, 2005. http://repo.lib.auburn.edu/EtdRoot/2005/SPRING/Forestry_and_Wildlife_Sciences/Dissertation/KOONS_DAVID_55.pdf.
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Aldea, Daniel. "Amphioxus illuminates the origin of the vertebrates' head." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066704/document.
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L'apparition de nouvelles structures telles que la crête neurale, les placodes et le mésoderme crânien a été essentielle pour l'émergence de la tête des vertébrées. Fait intéressant, le mésoderme de la tête des vertébrés n'est pas segmenté alors qu'il est supposé que le mésoderme de l'ancêtre de tous les chordés était totalement segmenté. De même le corps du le céphalochordé amphioxus est entièrement segmenté. Des travaux menés par l'équipe ont montré le rôle central du signal FGF dans la formation des somites les plus antérieures chez l'amphioxus. Afin de mieux comprendre le rôle de ce signal pour la formation de ces somites, nous avons réalisé une étude transcriptomique comparative par RNA-seq. Cette analyse a mis en évidence plusieurs gènes que sont impliqués dans la somitogenèse et la myogenèse et sous le contrôle du signal FGF. Nous avons pu montrer grâce à des analyses fonctionnelles que ER81/Erm/PEA3 et Six1/2 ont un rôle majeur dans la formation des somites les plus antérieures chez l'amphioxus. Inversement, Pax3/7 est impliqué dans la formation des somites postérieures. Cette cascade de régulation est semblable à celle observée lors de la somitogenèse pour les muscles du tronc chez les vertébrés, mais diverge de la cascade de gènes contrôlant la formation des muscles de la tête chez les vertébrés. Tous ces résultats supportent l'hypothèse selon laquelle le changement de fonction du signal FGF durant le développement précoce a été une étape clé pour la perte des somites antérieures, libérant ainsi les contraintes dans la partie antérieure de l'embryon et permettant dans un second temps l'acquisition des muscles de la tête chez l'ancêtre commun des vertébrésA central question in Evo-Devo is to understand the origin of the vertebrates’ head. The appearance of new structures such as the neural crest, placodes and a cranial mesoderm were essential for the appearance of the head in the vertebrates. Interestingly, it is supposed that the ancestor of all chordates was completely segmented. Remarkably, the cephalochordate amphioxus is completely segmented in the full length of its body as the hypothetical ancestor of all chordates. Moreover, it has been showed that the FGF signal plays a central role in the formation of the anterior-most somites of amphioxus. Thus, in order to understand the downstream signaling pathway under the control of the FGF signal for the formation of the anterior-most somites in amphioxus, we performed a comparative RNA-seq analysis. This analysis revealed several vertebrates orthologues genes playing roles in somitogenesis or myogenesis and under the control of the FGF signal. Furthermore, functional analysis revealed that ER81/Erm/PEA3 and Six1/2 plays majors roles in the formation of the anterior-most somites in amphioxus. Conversely, Pax3/7 is involved in the formation of the posterior somites. This regulatory cascade resembles that for the control of trunk somitogenesis in vertebrates and diverges from the gene cascades controlling the formation of the vertebrate head muscles. Altogether, our results strengthen the hypothesis that changes in the FGF function during early development were instrumental for the loss of anterior somites, releasing developmental constraints in the anterior part of the embryo and allowing a secondary acquisition of head muscles in the ancestor of vertebrates
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Meynert, Alison Maria. "Function and evolution of regulatory elements in vertebrates." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608495.
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Pedersen, Ragnor Thor. "The fate of an oestrogenic alkylphenol in vertebrates." Thesis, University of Sussex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324149.
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Guo, Lei. "The Molecular Mechanisms of Sex Determination in Vertebrates." Thesis, The University of North Dakota, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10274673.
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Many reptiles display temperature-dependent sex determination (TSD), in which the primary sex is determined by incubation temperatures rather than sex chromosomes. However, temperature is not the only factor that play critical roles in sex determination in the species with TSD. Previous studies in the snapping turtle, a species with TSD, showed that dihydrotestosterone (DHT) induces ovary development at temperatures that normally produce males or mixed sex ratios. In addition, the feminizing effect of DHT was found to be associated with increased expression of the ovary-determining gene Foxl2, suggesting a potential androgen-Foxl2 regulatory mechanism. This dissertation aims to clarify the molecular mechanisms underlying TSD in several aspects. First, determine the role of androgen in TSD; second, identify novel thermosensitive genes involved in TSD and lastly, reconstruct gene regulatory networks underlying sex determination.
To test the hypothetical androgen-Foxl2 interaction, I cloned the proximal promoter (1.6 kb) and coding sequence for snapping turtle Foxl2 (tFoxl2) in frame with mCherry, a red fluorescent protein. The tFoxl2-mCherry fusion plasmid or mCherry plasmid were stably transfected into mouse KK1 granulosa cells. Although expression of tFoxl2-mCherry was not affected by androgen treatment in KK1 cells, androgen inhibited expression of the endogenous mouse Foxl2 gene, suggesting the androgen-Foxl2 interaction does exist but it differs between species. We also found tFoxl2-mCherry potentiated low dose DHT effects on aromatase expression, which has not been reported in any other studies.
To identify novel sex-determining genes in TSD, I first de novo assembled and annotated the transcriptome of the snapping turtle using next-generation sequencing (NGS) and then performed RNA-seq analyses on the newly assembled reference transcriptome. With the differential gene expression analyses, I identified 293 thermosensitive genes. Among these genes, I find AEBP2, JARID2, and KDM6B of particular interest because these genes could influence expression of many other genes via epigenetic modifications.
To further investigate the molecular mechanisms underlying sex determination, I reconstructed gene regulatory networks using an entropy based network reconstructing algorithm—ARACNE with public microarray experiments in mouse gonads. The subsequent hub gene analyses revealed the basic molecular pathways underlying gonadal development and the master regulator analyses identified 110 candidate sex-determining genes including both known sex-determining genes and novel candidate genes.
My findings demonstrate that androgens can influence expression of key ovarian genes but further studies are needed to understand the androgen signaling in TSD. Furthermore, my study provides a first description of the snapping turtle transcriptome and the effects of temperature on transcriptome-wide patterns of gene expression during the TSP. In addition, hub genes and master regulators identified for mammalian gonad determination will guide the direction of future studies in the field of sex determination. However, additional studies are needed to validate the computational findings.
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Hessling, Elin. "Comparing the serotonergic system in vertebrates and invertebrates." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-141218.
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The serotonergic system is involved in a broad range of functions in both vertebrates and invertebrates and is highly conserved across taxa. Serotonin is an important monoamine acting in the brains of humans and animals, and has large and varying influences on many aspects of an individual’s life. For example, in humans, serotonin modulates feelings of happiness and in fruit flies, higher levels of serotonin increase aggression. In humans, an abnormal serotonergic system can result in health issues, such as depression and obsessive compulsive disorders, for which medications have been developed, including selective serotonin reuptake inhibitors (SSRI). Because the serotonin system has a large influence on human health, understanding how it functions is of great interest to researchers. Using comparative studies to explore differences in the serotonin system across taxa can provide insight into the mechanistic details of the system. To investigate if the serotonin system is comparable between vertebrates and invertebrates, a literature study with particular focus on receptors and proteins involved was performed. In addition, this report takes part in an experimental study investigating the effect of the SSRI fluoxetine in Mediterranean field crickets. Fluoxetine reduced exploration propensity of crickets, which was reversed, compared to what was anticipated and compared to effects seen in vertebrates. The literature review suggests that serotonin receptors are quite similar, but that proteins differ more when comparing vertebrates and invertebrates. This offers a likely explanation as to why results of studies on these different groups of animals may differ.
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Dodson, Helen. "Analysis of the spindle assembly checkpoint in vertebrates." Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/13671.
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I have cloned the chicken BubR1 cDNA and raised antibodies to the protein. The protein is highly conserved when compared to other vertebrate BubR1s with 55% identity and 70% similarity to human. The antibody recognises a protein of approximately 150 kDa and stains the kinetochores of chicken cells during prometaphase with the signal disappearing as they become attached to microtubules, a localisation typical of spindle checkpoint proteins. In order to further characterise the function of this protein in vertebrates, I have attempted to generate a chicken DT40 cell line conditionally null for BubR1. I have successfully targeted one allele of the BubR1 locus in DT40 cells. BubR1 (+/-) cells grow normally and have an intact checkpoint. Since I expect BubR1 to be essential, the gene must be expressed under the control of the tetracycline operator in the heterozygote cells. Attempts to target the second allele have failed thus far although the expected targeting frequency is 1/20 clones. It appears that expression of exogenous BubR1 is detrimental to these cells and they shut off expression when possible. It seems that expression levels of this essential checkpoint component are critical to avoid problems within the cell. In addition to this study in chicken cells I have cloned two other vertebrate checkpoint components from Xenopus laevis. The proteins Zw10 and Rod were initially identified in Drosophila and since no homologues have been identified in yeast these are considered as metazoan-specific components of the spindle assembly checkpoint. In order to study the checkpoint and the kinetochore, I have cloned partial Xenopus cDNA for Zw10 and Rod and raised antibodies to these proteins. Zw10 is localised to the kinetochores of metaphase Xenopus cells and along with Rod is present in a complex of approximately 11S in Xenopus egg extracts.
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Lau, Tze Chin. "In vitro and in vivo analyses of the impact of Mab21l2 and its targets on neural patterning and differentiation in vertebrates /." View abstract or full-text, 2010. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202010%20LAU.
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Whitaker, Helen. "Molecular genetic studies of vertebrate ecology the analysis of senescence, offspring sex ratio variation and population diversity /." Thesis, Connect to e-thesis, 2002. http://theses.gla.ac.uk/1014/.
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Thesis (Ph.D.) -- University of Glasgow, 2002.Ph.D. thesis submitted to the Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, University of Glasgow, 2002. Includes bibliographical references (p. 161-195). Print version also available. Mode of access : World Wide Web. System requirements : Adobe Acrobat reader required to view PDF document.
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Bremer, Oskar. "Silurian vertebrates of Gotland (Sweden) and the Baltic Basin." Doctoral thesis, Uppsala universitet, Evolution och utvecklingsbiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328234.
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During the Silurian, the Swedish island Gotland was positioned close to the equator and covered by a shallow sea called the Baltic Basin. The sedimentary rocks (predominantly carbonates) comprising most of the island today were initially formed in this warm sea, and the relatively complete succession of rocks often contains fossil fragments and scales from early vertebrates, including heterostracans, anaspids, thelodonts, osteostracans, acanthodians, and a stem-osteichthyan. Fossils of early vertebrates become increasingly more common in younger Silurian rocks, but are mostly represented by fragmentary remains and rarer occurrences of articulated jawless vertebrates (agnathans). However, the record of articulated specimens and jawed vertebrates (gnathostomes) are more numerous in rocks of the following Devonian Period. Isolated peaks of agnathan diversity during the Silurian and disarticulated remains of gnathostomes from this period hint at a cryptic evolutionary history. A micropaleontological approach with broader sampling may provide a better understanding of early vertebrate distribution patterns and hopefully give some insights into this history. The objective of this study was to build upon previous sampling on Gotland and to use established frameworks for disarticulated remains with the aim of making comparisons with similar studies performed in the East Baltic. However, difficulties locating the collections from these previous works necessitated a different focus. Undescribed museum collections and newly sampled material enabled some taxonomical revisions and greatly improved the understanding of vertebrate distribution in the youngest part of the Gotland sequence. It also indicated that this interval may represent the early stages of the diversification of gnathostomes that become increasingly dominant toward the end of the Silurian. Furthermore, the description of samples from partly coeval sections in Poland enabled some preliminary comparisons outside of Gotland, and presented a striking example of restricted environmental occurrences for a thelodont taxon. This is encouraging for future sampling and investigations on Gotland. Together with the establishment of a facies-framework comparable to that developed in the East Baltic and correlations to other areas, this may prove fruitful for an increased understanding of early vertebrate distribution and evolution during the Silurian.
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Blundell, James Edward. "The development and evolution of vertebrate electroreceptors." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610516.
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Shultz, Susanne Marie. "Of monkeys and eagles : predator-prey interactions in the Taï National Park, Côte d'Ivoire." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288247.
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Elango, Navin. "Evolutionary impacts of DNA methylation on vertebrate genomes." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26691.
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Thesis (Ph.D)--Biology, Georgia Institute of Technology, 2009.Committee Chair: Dr. Soojin Yi; Committee Member: Dr. Eric Vigoda; Committee Member: Dr. James Thomas; Committee Member: Dr. John McDonald; Committee Member: Dr. Kirill Lobachev; Committee Member: Dr. Michael Goodisman. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Molinari, Micol Ariella. "Nitric oxide synthase and the contribution of nitric oxide to vertebrate motor contol /." St Andrews, 2008. http://hdl.handle.net/10023/489.
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Brazeau, Martin D. "Endocranial Morphology and Phylogeny of Palaeozoic Gnathostomes (Jawed Vertebrates)." Doctoral thesis, Uppsala universitet, Evolutionär organismbiologi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9360.
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Gnathostomes, or jawed vertebrates, make up the overwhelming majority of modern vertebrate diversity. Among living vertebrates, they comprise the chondrichthyans (“cartilaginous fishes” such as sharks, skates, rays, chimaeras) and the osteichthyans (“bony fishes” or bony vertebrates, inclusive of tetrapods). Gnathostomes appear to have originated in the early Palaeozoic Era, but their early fossil record is fairly scant. The best fossils appear first in the Late Silurian and Devonian periods. Much of gnathostome diversity owes to unique adaptations in the internal skeleton of their head (the endocranium). The endocranium is composed of the braincase, jaws, hyoid arch, and branchial arches, which sometimes fossilise when they are composed of bone or calcified cartilage. The purpose of this thesis is to describe and compare the fossilised cranial endoskeletons of a variety of different Palaeozoic gnathostomes. The objective is to test current conceptions of gnathostome interrelationships (i.e. phylogeny) and infer aspects of key morphological transformations that took place during the evolution of Palaeozoic members of this group. Two key areas are examined: the morphology and interrelationships of Palaeozoic gnathostomes and the morphology of the visceral arches in sarcopterygian fishes. New data on the visceral arches are described from the stem tetrapods Panderichthys and rhizodontids. These provide insight into the sequence of character acquisition leading to the tetrapod middle ear. Panderichthys shows key features of the tetrapod middle ear chamber were established prior to the origin fo digited limbs. New morphological data are described from the “acanthodian” fish Ptomacanthus. Ptomacanthus provides only the second example of a well-preserved braincase from any member of this group. It shows dramatic differences from that of its counterpart, Acanthodes, providing new evidence for acanthodian paraphyly. New interpretations of basal gnathostome and osteichthyan phylogeny are presented, challenging or enriching existing views of these problems.
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Shi, Yongsheng. "Molecular genetics and evolution of UV vision in vertebrates." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2002. http://wwwlib.umi.com/cr/syr/main.
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Foster, Eric D. "Acceptor splice site prediction in vertebrates using probabilistic models /." Online version of thesis, 2007. http://hdl.handle.net/1850/4629.
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Civallero, Edgardo. "UDC Biology Revision Project: First Stage: Class 59 Vertebrates." UDC Consortium, 2010. http://hdl.handle.net/10150/200632.
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The paper presents and describes the work on the revision of the zoology of vertebrates, which is published in E&C 32 and introduced in UDC MRF 2010. This is the first stage of a larger project of revision, correction and update affecting all tables related to systematics (zoology, botany, microbiology and virology) to be undertaken from 2011-2013. The first part of the paper briefly introduces the current systems of classification of living and extinct beings, and explains how different perspectives with respect to the arrangement of biological entities have been reflected (or not) in the UDC schedules. The second part gives an overview of problems detected in UDC prior to this revision and explains solutions that were implemented in UDC MRF 2010 indicating tools and methods used in this work.
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Nicol, Alister U. "Adaptive functions of sustained potential shifts in lower vertebrates." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334592.
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Gavinio, Roberto. "PINK1 and Parkin complementarily protect dopaminergic neurons in vertebrates." Kyoto University, 2013. http://hdl.handle.net/2433/180338.
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Nabiyouni, Maryam. "Mega-scale Bioinformatics Investigation of Codon Bias in Vertebrates." University of Toledo Health Science Campus / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=mco1308092740.
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Shone, Victoria Louise. "Development, morphogenesis and evolution of pharyngeal segmentation in vertebrates." Thesis, King's College London (University of London), 2014. https://kclpure.kcl.ac.uk/portal/en/theses/development-morphogenesis-and-evolution-of-pharyngeal-segmentation-in-vertebrates(702414ad-be81-457a-8f2f-ca7dffb46280).html.
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Pharyngeal arches are bulges found on the lateral surface of the head of vertebrate embryos. They are lined externally by ectoderm and internally by endoderm, with a mesenchymal core of neural crest cells and mesoderm. Lateral expansion of pockets of endoderm form pharyngeal pouches at specific locations along the pharynx. Each one of these aligns with invaginating portions of overlying ectoderm to form the anterior and posterior border of each pharyngeal arch. Current studies suggest endoderm plays a prominent role in patterning the arches, but little is known about how this tissue develops and is organised. Investigation of pharyngeal pouch morphogenesis revealed morphological differences between anterior and posterior pouches. These region-based differences are also evident during epithelial interaction at each ectoderm/endoderm interface, where the first interface does not sustain direct contact in contrast to those posteriorly. This results in the fusion and subsequent breakdown of their basement membranes and cell death of the overlying ectoderm. I have revealed that this morphogenetic program for posterior pouch development is conserved in vertebrates and outpocketing of the pouch endoderm represents an early conserved stage of ‘gill’ development. To molecularly characterise the differences between anterior and posterior pharyngeal regions I examined Hox gene expression revealing alignment with specific pouches, thereby separating the pharynx into anterior and posterior regions. Furthermore, the most posterior pouch is demarcated by Hoxb1 expression, so as new pouches form this expression ‘moves’ posteriorly. This dynamic expression pattern is conserved and therefore may underlie how pouch number is controlled within each species. Moreover, a general trend toward a reduction in the number of pharyngeal arches has occurred with vertebrate evolution and I have localised this reduction to the posterior pharyngeal region. By using morphogenetic, molecular and comparative anatomical data I have characterised pharyngeal development and highlighted key differences in anterior and posterior regions reflecting the two main functions of the pharynx: feeding and respiration. As vertebrates transitioned from water to land, their method of respiration was adapted and this is reflected by the reduction in posterior pharyngeal segments in tetrapod species.
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Hidalgo, Sastre Ana. "Crosstalk between Notch and Wnt signalling pathways in vertebrates." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/crosstalk-between-notch-and-wnt-signalling-pathways-in-vertebrates(9b4411a3-cd03-4af3-b3b5-8c432c7a2c68).html.
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The development of complex metazoans depends on the integration of a handful of signalling pathways that eventually modulate precise patterns of gene expression. The fact that just a few pathways are involved in the generation of such complexity in different organisms, suggests that these are highly regulated and conserved processes. The accurate spatio-temporal coordination of the signalling pathways controls the assignation of different cell fates and their patterning into tissues and organs. The source of diversity relies on the different possible interactions between signalling pathways, such as, the combination of signals and the order in which they are received by the cell or crosstalk. Due to their importance in development, abnormal signalling through these pathways has been strongly associated with developmental disorders, cancers and other diseases. The Notch and Wnt signalling pathways are key components of the intricate network that controls gene expression during development, and genetic analysis in Drosophila has highlighted that interactions between these two signalling pathways are important during this process.This thesis investigates the cross-regulatory interactions between Notch and Wnt signalling pathways in mammals. Using transcriptional reporter assays and biochemical analysis, I have found two molecular mechanisms underlying the inhibitory crosstalk between Notch and β-catenin, the effector of Wnt signalling pathway, in mammalian cells. At the membrane Notch inhibits β-catenin transcriptional activity through Deltex mediated endocytosis of Notch and a component required for β-catenin activation. This is similar to results observed in Drosophila. In the nucleus, I have identified a novel mechanism by which NICD-dependent transcription of Hes/Hey family of transcription factors prevents the activation of Wnt signalling pathway. This mechanism involves the formation of a physical complex between Hey1 and β-catenin/TCF, which allows Hey to block Wnt transcriptional activation. Additionally, I have found that these two mechanisms are conserved across vertebrates.Together the findings of this thesis improve our understanding of the molecular mechanism underlying the Notch/Wnt crosstalk. In turn, this will give an insight into unravelling how a handful of signalling pathways can generate sufficient diversity in signalling output to specify the hundreds of different cell fates generated to make a mammal. Elucidating these signalling networks will also contribute to our understanding of diseases, both their aetiology, by knowing how changes in one signal can influence another, and their treatment as mimicking points of crosstalk is likely to generate very specific therapeutic agents.
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Petruti-Mot, Anca. "Genetic and functional analysis of topoisomerase II in vertebrates." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/8985.
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The degree of DNA supercoiling in the cell is carefully controlled by DNA topoisomerases. These enzymes catalyze the passage of individual DNA strands (Type I DNA topoisomerases), or double helices (Type II DNA topoisomerases) through one another. The purpose of the present study is to conduct a detailed analysis of the topo llα and β mRNAs expressed in several vertebrate cell lines. The final aim of this project is to analyze the relative roles of topo llα in chromatin condensation and chromosome segregation during mitosis, by performing topo llα gene targeting experiments in the DT 40 chicken lymphoblastoid cell line. The knock-out strategy was based on the observation of a high rate of homologous recombination versus random integration in the DT40 cell line. The topo llα gene was shown to be located on the chicken chromosome 2 (APM unpublished), for which the DT40 cell line is trisomic. The targeting vector completely replaced the 32 kb topo IIα genomic locus, generating a topo llα (-/+/+)cell line, which showed an increased resistance to topo II inhibitors. Paradoxically, 150 uM etoposide or 100 uM mitoxanthrone induced apoptosis within 5 hours in the topo llα (-1+1+) cell line, more rapidly as compared to the normal DT 40 cells. A topo IIα (-I-I+) cell line has also been generated. This study revealed the presence of evolutionarily conserved alternatively spliced forms of both topo llα and β isoforms between birds and humans. Hybridization screening of two chicken cDNA libraries, MSB-1 and DU249, revealed the presence of two distinct forms of both topo llα and β cDNAs. One form of topo llα, designated topo llα-1, encodes the chicken topo llα amino acid sequence previously reported (dbjiAB007445) in the database (unpublished). The second form, designated topo llα-2, encodes a protein containing an additional 35 amino acids inserted after Lysine-322 of chicken topo IIα-1 protein sequence. In the case of topo 11(3 mANA, one form, designated topo IIβ-1, encodes the protein already described (dbjiAB007446). The second form, tapa IIβ-2, would encode a protein missing the next 86 amino acids after Valine-25 in tapa II β-1 protein sequence. The tapa 11β variant is positioned similarly to one previously described in human (Hela) cells. The 5 amino acid insertion in the human tapa 11β-2 variant follows v23. In chicken cells, a longer insertion of 86 amino acids sequence follows v25, the homologous position in the tapa 11β protein. In human cells, the situation with tapa llα is more complex, as revealed by RT-PCR experiments (APM, unpublished) which generated several bands. One of these amplified species was found to contain a 36 amino acids insertion, positioned after residue K321 in the human tapa IIα cDNA, similarly to chicken tapa IIα-2 variant. The second human tapa llα spliced form cDNA was shown to contain a 26 amino acids insertion after residue A401 in the canonical human tapa llα protein sequence. The third cDNA variant isolated from human cells was described to encode a 81 amino acids insertion after residue Q355 positioned within the known human tapa IIα protein. It appears possible that the posttranslational modifications of the a-2 and β-2 isoforms may differ substantially from those of the canonical a-1 and β-1 isoforms. Such variant proteins could fulfil specialized functions, which might be tissue or cell-type specific. In summary, two novel forms of tapa llα and β cDNAs have been identified in three chicken cell lines. These spliced versions of both tapa llα and 13 isoforms seem to be evolutionary conserved, with similar forms occurring in their human counterparts. Future functional analysis of vertebrate tapa IIα and β will have to account for the existence of these novel isoforms, which might encode proteins that may exhibit different regulation of their subcellular localization, interaction with other proteins, or catalytic activity.
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Whiting, James R. "The evolutionary consequences of genetic adaptation to parasitism." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/50591/.
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The processes driving and maintaining variable immune responses are poorly understood compared with other aspects of an organism’s ecology. This is particularly true from an evolutionary perspective, as the evolutionary relationships between immune responses and other traits and processes in nature remain inadequately explored. I investigated these associations in this thesis using the three-spined stickleback system as an evolutionary and immunological model. I combined sampling of wild individuals with genomic analyses to demonstrate phenotypic and genomic associations between immune responses and life history evolution across multiple populations. I also observe how experimental changes in daylength, a seasonal cue, modulate immune responses and increase parasite susceptibility in a controlled laboratory experiment. These findings occur independently of natural variation in parasite resistance. Stickleback are also a model for studies of speciation. I used sampling of wild hybrids to assess the significance of immune variation in postzygotic isolating mechanisms between diverging ecotypes; although my findings suggest a minor role. Finally, I demonstrate that genomic responses to parasitism and abiotic environmental variation are repeatable across independent, intercontinental adaptive radiation events in sticklebacks; conferring a repeatability of the evolutionary relationships of immune variation documented in this thesis. The findings within this thesis therefore provide novel insights into poorly explored or open areas of research regarding how variable immune responses evolve in nature.
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Vitale, Jessica. "The olfactory behaviour of spotted hyaenas (Crocuta crocuta) and sympatric mammals in the Okavango Delta, Botswana." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/48855/.
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Understanding the natural behaviour and coexistence of species is important for the conservation of intact ecosystems, and behavioural studies can enhance our knowledge of processes such as communication and competition. I investigated the social dynamics and scent-marking behaviour of spotted hyaenas (Crocuta crocuta), and the occurrence of interspecific olfactory eavesdropping among African mammals, within the Okavango Delta ecosystem of Botswana. First, social network analysis found that the hyaena population was comprised of five main clans that maintained territories but whose home ranges overlapped considerably. Scavenging at large carcasses involved associations between individuals from different clans and resulted in relative tolerance toward territorial intruders. Second, observations of communal latrine use found that latrines are likely involved in territorial advertisement by hyaena clans, and cyclical patterns of latrine growth and decline were linked to annual rainfall. Third, a translocation experiment showed that hyaena scats appear to be less important for hyaena communication than other cues associated with latrines, especially as hyaenas did not differ in their behaviour towards scat originating from latrines located in resident versus non-resident clan home ranges. Heterospecific mammals investigated, scent-marked, and were vigilant at hyaena latrines, suggesting a potential function for hyaena latrines in interspecific eavesdropping and/or communication. Fourth, a urine presentation experiment found that the investigation of sympatric predator urine by African mammals stimulated vigilance behaviour, suggesting that olfactory signals provide information about predation risk. Hyaenas exhibited context-specific differences in behaviour towards predator urine: they were more likely to investigate urine samples alongside indicators of predator activity (i.e. carrion odour, carcasses) and were most likely to exhibit vigilance at carcasses when exposed to urine from lions and wild dogs. This study greatly enhanced our understanding of spotted hyaena behaviour within the Okavango Delta, an important ecosystem for the conservation of African large predators. Furthermore, this study provided the first experimental evidence of the role of hyaena scats in intraspecific communication and interspecific olfactory eavesdropping at latrines. My research findings regarding the population’s clan structure and home ranges will form the foundation for subsequent investigation into human-wildlife conflict in the study area. Furthermore, the results from two scent experiments shed light on the potential importance of olfactory signals for mediating interspecific interactions among African mammals, particularly among large predators.
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Jones, Christopher David Stanford. "On the cross-sectional form of the patella in several primates." Title page, table of contents and abstract only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phj764.pdf.
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Hocknull, Scott Alexander Biological Earth & Environmental Sciences Faculty of Science UNSW. "Late Cainozoic rainforest vertebrates from Australopapua: evolution, biogeography and extinction." Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44580.
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Understanding the evolution, biogeography and extinction of Australopapuan vertebrate lineages is fundamental to determining baseline responses of those groups to past environmental change. In light of predicted climatic change and anthropogenic impact, it is imperative to determine the trajectories of Australia???s modern flora and fauna. In particular, mesothermic rainforest faunas are among Australia???s most vulnerable terrestrial biota under threat from both natural and anthropogenic causes. There is a gap in knowledge of past patterns of change and, in particular, a conspicuous lack of direct evidence of response of rainforest faunas to past climatic change. This study documents the late Cainozoic Australopapuan rainforest vertebrate record and its response to environmental change via adaptive radiation, biogeographical change and extinction. In particular, it provides the first detailed systematic appraisal of Quaternary fossil sites and local faunas from northern Australia. The study documents the only known Quaternary mesothermic rainforest fauna in Australia and its transition to a xeric-adapted fauna during the middle Pleistocene. The fossil assemblages analysed are comprised of dozens of species, including several new genera and species. Each fossil taxon shares a close phylogenetic relationship with others either known only from the Australian Tertiary record or from Quaternary-Recent New Guinea and Wet Tropics rainforests. The presence of many species is evidence of previously much larger distributions followed by subsequent massive range retractions. Detailed documentation of this rare fauna testifies to rainforest stability in central eastern Queensland until approximately 280,000 years ago, when the development of an El Nino dominated climate generated variable climatic patterns that could not support aeseasonal rainforest. Extinction of this late Pleistocene rainforest fauna serves as one of only two examples of major rainforest faunal turnover in Cainozoic Australia, the other occurring in the late Miocene. These two major extinction events are compared. The late Pleistocene faunal extinction differs from the late Miocene event in being biased towards large-bodied, terrestrial herbivores and carnivores (both reptile and mammal). This study also combines fossil and phylogenetic data with latest understanding of palaeogeography, tectonics and sea level history along Australia???s northern margin to provide hypotheses of faunal dispersal between New Guinea and mainland Australia throughout the Neogene.
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Furtado-Neto, Manuel Antonio de Andrade. "Molecular systematics and population genetics of marine vertebrates from Brazil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ36203.pdf.
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Wacksman, MItch. "Impact of atrazine on chlorpyrifos toxicity to four aquatic vertebrates /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1136077891&sid=35&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Bales, Mark. "Molecular regulation of gene expression in anterior mesendoderm of vertebrates." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280000.
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The signaling pathways that regulate the fate of cells located in the anterior lateral (AL) region of the vertebrate embryo are not well understood. Mesodermal cells in this region will assume the heart muscle phenotype while adjacent endoderm gives rise to foregut tissues such as the liver. The AL endoderm supplies key signaling molecules to promote the survival and differentiation of the precardiac mesoderm. These AL endoderm factors are know to up-regulate transcription factors, such as Nkx2--5, that regulate cardiac genes. However, little is known about how the AL endoderm is patterned and the exact mechanism by which the cardiac transcription factors function within the mesoderm. Therefore, two projects were pursued to understand the developmental pathways that promote early heart development. One project looks at defining the mechanism by which the Nkx2 homeobox genes regulate cardiac gene expression in mouse embryonic stem cells. Unfortunately, this project was plagued with difficulties. Mouse ES cells were used as a model system to study cardiac differentiation. However, these cells were found to contain a potent genome protection mechanism that prevented the stable integration of transcription factors. This phenomenon is addressed and discussed within the thesis. The second project defines the role of retinoids in patterning the AL endoderm. In this study, the homeobox gene cHex, a gene required for hepatocyte development, was used as an AL endoderm marker. It was found that retinoids act directly on the cHex gene promoter to reduce its activity and restrict its expression domain to the AL endoderm.