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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.
51

The osteology and relationships of aquatic eosuchians from the Upper Permian of Africa and Madagascar /

Currie, Philip J. January 1981 (has links)
Tangasaurid eosuchians are represented by hundreds of specimens from the Permo-Triassic strata of Madagascar and Africa. The confusion surrounding the identification and anatomy of these reptiles is resolved by comparative anatomy and relative measurements, and three genera, Thadeosaurus, Tangasaurus and Hovasaurus, are described. Extensive growth series present a unique opportunity to study differences in growth strategies in two closely related Permian genera, one that was terrestrial (Thadeosaurus) and the other aquatic (Hovasaurus). The vertebrae of Youngina have a derived character state that indicates close relationship with the tangasaurids. A new genus and species of eosuchian, Acerosodontosaurus piveteaui, has a specialized feature in the carpus that is found in the Tangasauridae. The relationships between tangasaurids and other eosuchians are considered.
52

The impact of habitat loss and habitat fragmentation on the survival of the herpetofauna in the southern Mount Lofty Ranges, South Australia /

Sacchi, Marco P. Unknown Date (has links)
Over the relatively short period since European settlement in the 1830’s, the Mount Lofty Ranges (MLR) in South Australia have suffered a precipitous decline of natural habitat. The effects of habitat fragmentation on the herpetofauna of the southern MLR were investigated in a series of forest remnants and provide the thematic background of this thesis which focuses on five separate but thematically interconnected aspects of habitat fragmentation that are presented in separate, semi-autonomous chapters (3-7). / The study confirmed that the original herpetofauna still persists in the southern MLR. Habitat fragmentation apparently did not affect the species richness of the region. However, there are important differences in the occurrences of individual species across the archipelago of forest remnants. The distribution patterns of the herpetofauna in forest remnants of the southern MLR are not random but highly nested. As a consequence of a significant association of species richness with the area, it appears that the proportion of the original forest-dependent reptiles of the MLR that can be preserved in habitat fragments is a direct function of the remnant size. The processes responsible for the observed deterministic extinction patterns appear to be habitat loss and habitat fragmentation. Contrary to many forest-dependent reptiles, most amphibian species are still widespread at the investigated scale and generally appear to be less affected by the effects of forest loss and forest fragmentation in the MLR. / Actual habitat remnancy in the southern MLR is below 13% and with 97.6% of all forest fragments smaller than 100ha, many of the most area-sensitive f orest-dependent reptiles survive in just a handful of remnants that are large enough to support viable populations. Although smaller remnants still support some forest- dependent reptiles, their herpetofauna is generally greatly impoverished. While abundances of most species were too low to estimate expected recapture values in dispersal experiments, crossings of common anthropogenic boundaries by local reptiles appear to be rare events. Where expected recapture values could be estimated, such as for L. guichenoti in a case study, most boundaries did appear to show a filter effect. Differences existed among species and communities in regard to boundary permeability. The results suggest that the extensive road network in the southern MLR, through filter effects (i.e. road mortality) and barrier effects (i.e. edge avoidance), is likely to decrease landscape connectivity. The study further demonstrated the existence of significant edge effects on reptiles. Such edge effects are expected to have a particularly large impact on populations of smaller forest fragments that are mostly or completely ecotonal and, consequently, harbour mostly edge-tolerant forest species and habitat generalists. / The above-mentioned case study of Lampropholis guichenoti demonstrated that this ubiquitous species is naturally abundant not only under relatively pristine conditions, but also in disturbed habitat. The species apparently possesses a variety of biological, ecological and behavioural traits, such as a high degree of ecological plasticity, non-territoriality and klepto-parasitic behaviour that may explain its relatively successful survival in the face of extensive habitat fragmentation in the southern Mount Lofty Ranges. / Findings of this study have clear implications for conservation and restoration planning. Nested subset analysis emerged as a useful analytical tool to identify potential focal species that could serve in the development of a taxon-based surrogate scheme. This multi-species approach could be a simple and cost-effective way to address regional conservation problems when time and resources are limited. A focal-species approach using forest dependent reptiles in a surrogate scheme appears particularly useful for herpetofaunal diversity conservation in forest remnants of the MLR. / Thesis (PhD)--University of South Australia, 2004.
53

Development of the pulmonary surfactant system in non-mammalian amniotes /

Johnston, Sonya D. January 2001 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Physiology, 2001. / "March 2001". Bibliography: leaves 193-238.
54

Studies on background color selection in two species of lizards (Holbrookia maculata subspecies and Phrynosoma modestum)

Meyer, Delbert Eugene, January 1959 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Abstracted in Dissertation abstracts, v. 19 (1959) no. 7, p. 1876. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 85-87).
55

Purification and characterization of bovine parathyroid peptide

Glass, J. David January 1965 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 31-33.
56

Investigating genetic population substructure of an Australian reptile tick, Bothriocroton hydrosauri, using highly polymorphic microsatellite markers

Guzinski, Jaromir Anthony. January 2008 (has links)
Thesis (Ph.D.)--Flinders University, School of Biological Sciences. / Typescript bound. Includes bibliographical references: (leaves 135-157) Also available online.
57

Filogenia molecular da família Dipsadidae (serpentes : Colubroidea)

Grazziotin, Felipe Gobbi [UNESP] 21 December 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-21Bitstream added on 2014-06-13T21:08:02Z : No. of bitstreams: 1 grazziotin_fg_dr_rcla.pdf: 876560 bytes, checksum: 3e4c47b55167b94d86962842d103f78a (MD5) / A relação filogenética entre os caenofídeos (serpentes avançadas) tem sido matéria de debate durante décadas. As principais questões para a sistemática eram representadas pela condição monofilética da família Colubridae, e a composição de sua subfamílias. Mais recentemente, novos métodos para inferir filogenias baseadas em critérios objetivos, bem como a utilização da biologia molecular, lançaram alguma luz sobre estas questões tradicionais. Aqui, são apresentados os resultados de duas análises filogenéticas moleculares das serpentes cenofídeas, focando principalmente nas serpentes neotropicais (subfamílias Xenodontinae e Dipsadinae). Otimização direta com base na máxima parcimônia, e homologia estática (alinhamento múltiplo), utilizando máxima parcimônia e máxima verossimilhança foram aplicados em uma matriz expandida de dados molecular. Os principais resultados de ambas as análises são: posicionamento de Acrochordus, Xenodermatideos e Pareatideos como grupos irmãos sucessivos de todos os caenofídeos restantes; viperídeos e homalopsideos são clados irmãos sucessivos de todos as demias serpentes, foram recuperados os seguintes clados monofiléticos dentro do crown-group Caenophidia: psammofídeos Afro-Asiaticos (incluindo Mimophis de Madagascar), Elapidae, Pseudoxyrhophiinae, Colubrinae, Natricinae, Dipsadinae e Xenodontinae. Homoroselaps está associada com os atractaspidídeos. Dois grupos taxonômicos superiores dentro de Caenophidia e uma nova subfamília dentro Dipsadidae foram nomeados. As análises filogenéticas sugerem mudanças taxonômicas dentro dos xenodontíneos; cinco novas tribos, oito novos gêneros foram criados e dois gêneros foram ressuscitados. Os gêneros Xenoxybelis e Pseudablabes foram sinonimizados com Philodryas; Liophis e Umbrivaga com Erythrolamprus e Lystrophis e Waglerophis com Xenodon / The phylogenetic relationship among the caenophidian (advanced) snakes has been a matter of debate for decades. The principal issues for the systematic were represented by the monophyletic condition of the large family Colubridae, and the composition of its subfamilies. More recently, new methods for infering phylogenies based on objective criteria, and the use of molecular biology, shed some light on these traditional issues. Here, two molecular phylogenetic analyses of caenophidian snakes focusing principally in the Neotropical snakes (subfamilies Xenodontinae and Dipsadinae) are presented. Direct optimization based on maximum parsimony, and static homology (multiple alignment) using maximum parsimony and maximum likelihood were applied on a expanded molecular data matrix. The major results of both analyses are: placement of Acrochordus, Xenodermatids, and Pareatids as successive outgroups to all remaining caenophidians; viperids and homalopsids are sucessive sister clades to all remaining snakes; the following monophyletic clades within crown group caenophidians: Afro- Asian psammophiids (including Mimophis from Madagascar), Elapidae, Pseudoxyrhophiinae, Colubrinae, Natricinae, Dipsadinae, and Xenodontinae. Homoroselaps is associated with atractaspidids. Two higher taxonomic clades within Caenophidia one new subfamily within Dipsadidae were nomed. The phylogenetic analyses suggest taxonomic changes within xenodontines, five new tribes, eight new genera were created and two genera were resurrected. The genera Xenoxybelis and Pseudablabes were synonymize with Philodryas; Liophis and Umbrivaga with Erythrolamprus; and Lystrophis and Waglerophis with Xenodon
58

Determinantes do aumento metabólico pós-prandial em urutus, Bothrops alternatus (Serpentes, Viperidae) /

Gavira, Rodrigo Samuel Bueno. January 2011 (has links)
Orientador: Denis Otavio Vieira de Andrade / Banca: José Eduardo de Carvalho / Banca: Fernando Ribeiro Gomes / Resumo: O grupo das serpentes é formado por animais estritamente carnívoros que ingerem suas presas inteiras, sem mastigação. Algumas espécies podem tolerar períodos prolongados de jejum intercalados com ingestão ocasional de presas muito grandes em relação à sua massa corpórea. Tais serpentes apresentam, dentre todos os vertebrados, algumas das mais dramáticas especializações morfológicas, comportamentais e fisiológicas associadas à alimentação. Uma das consequências da ingestão de grandes massas de alimento é o excepcional aumento da taxa metabólica pós-prandial, referido como Ação Dinâmica Específica (ADE). A magnitude dessa resposta metabólica pós-prandial depende essencialmente do tamanho e da natureza do alimento, associado a fatores como o tamanho corpóreo e a temperatura do ambiente. No entanto, raros são os trabalhos que caracterizaram a ADE de espécies de serpentes neotropicais e examinaram os fatores que potencialmente poderiam afetar esta resposta. Deste modo, ao longo dos dois capítulos que compõem a presente dissertação, investiguei alguns dos determinantes proximais do aumento metabólico pós-prandial da urutu-cruzeiro, Bothrops alternatus (Serpentes, Viperidae). O capítulo I foi dedicado à investigação dos efeitos da temperatura e do termoperíodo sobre a ADE de Bothrops alternatus (Serpentes, Viperidae). O capítulo II foi dedicado ao estudo dos efeitos do tamanho da presa sobre a ADE de Bothrops alternatus (Serpentes, Viperidae). Nossos resultados mostraram que o aumento da temperatura corpórea é acompanhado por uma aceleração do processo digestivo às custas de um maior incremento metabólico. A variação destes parâmetros ocorre de maneira inteiramente proporcional de forma que a energética da ADE não foi afetada pela variação da temperatura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Not available / Mestre
59

Salmonella spp. en reptiles en cautiverio de la Región Metropolitana : presencia de genes de virulencia asociados a invasividad

Carmona Balbontín, Francisco Javier January 2015 (has links)
Memoria para optar al Título Profesional de Médico Veterinario / Las mascotas exóticas, especialmente los reptiles -ampliamente distribuidos por el mundo representan un alto riesgo para la Salud Pública, debido principalmente a su condición de portadores intestinales de Salmonella spp., estimándose que del total de casos de salmonelosis un 7% se asocia al contacto con reptiles (SAR). Del total de SAR un 15% aproximadamente presenta un cuadro invasivo, los cuales incluyen septicemia, meningitis, infección en cartílagos e inclusive la muerte. La invasividad de Salmonella se encuentra asociada a genes de virulencia, que se organizan principalmente en la isla de Patogenicidad 2 (SPI-2) de su genoma. En consideración a lo anterior el propósito de este estudio fue detectar genes de virulencia asociados a invasividad, en cepas de Salmonella spp. aisladas desde reptiles en cautiverio de la Región Metropolitana. En este estudio se seleccionaron cuatro genes de virulencia (spiA, sseG, ssaB, sscB) asociados a invasividad, específicamente a la sobrevivencia de esta bacteria al interior de macrófagos y su diseminación sistémica. De las 34 cepas analizadas, el perfil más frecuente encontrado fue spiA/sscB/sseG (35,2%), seguido por sscB/sseG/ssaB (8,8%), siendo los genes mayormente detectados sseG (91%), ssaB (71%) y sscB (61%), mientras que el gen spiA fue menor su detección (31%). Estos resultados constituyen la primera aproximación molecular de la potencial virulencia de cepas de Salmonella aislada desde reptiles en Chile. Se discuten los resultados con la variabilidad genética en cepas de diferentes fuentes animales y el hombre. / Exotic pets, especially reptiles, are widely distributed throughout the world, particularly in Chile, where a high percentage are intestinal carriers of Salmonella spp. (About 50%), representing a risk to public health. Thus, it is estimated that of all cases of salmonellosis in humans, about 6-7% is associated with contact with reptiles (RAS). Of total RAS, about 15% has a box-invasive, which include septicemia, meningitis, infection in cartilage and even death. Salmonella invasiveness is encoded in virulence genes that are organized primarily in Pathogenicity Island 2 (SPI-2). The purpose of this study was to detect genes associated with invasiveness virulence in Salmonella strains, isolated from reptiles in captivity in the Metropolitan Region. In this study, four virulence genes (spiA, sseG, ssaB, sscB) associated with invasiveness, and therefore, belonging to the pathogenicity island 2 were selected. These genes are related to the survival of the bacteria within macrophages and their systemic dissemination. Of the 34 strains tested, the most common profile was spiA/ sscB/ sseG (35.2%), followed by sscB/sseG/ssaB (8.8%), the most prevalent genes sseG (91%), ssaB (71%) and sscB (61%), while the spiA obtained a lower prevalence (31%). These results provide the first molecular approach of potential virulence of Salmonella strains isolated from reptiles in Chile. The results with the genetic viability in different strains of animals and humans sources are discussed.
60

Detección de genes de resistencia antimicrobiana en cepas de Salmonella spp. aisladas de reptiles en cautiverio, Región Metropolitana, Chile

Bittner Torrejón, Consuelo Alejandra January 2016 (has links)
Memoria para optar al Título Profesional de Médico Veterinario / La resistencia antimicrobiana es un fenómeno de gran importancia a nivel mundial, debido a sus consecuencias en la salud tanto humana como animal y también por las consecuencias económicas que genera. Entre las bacterias que presentan multirresistencia se encuentra Salmonella spp., patógeno distribuido mundialmente, generalmente transmitido por los alimentos, pero también por contacto directo o indirecto con su reservorios animales. Dentro de estos, adquieren relevancia los reptiles por ser portadores asintomáticos de la bacteria, constituyendo un reservorio que cada vez adquiere mayor importancia debido a la creciente popularidad que presentan como mascota en las familias actuales. En Chile existen escasos estudios sobre resistencia antimicrobiana en cepas de Salmonella spp. aisladas de reptiles que asocien genes a la resistencia fenotípica, razón por la cual, el objetivo del presente estudio apunta a la detección de genes de resistencia antimicrobiana en cepas de Salmonella spp. aisladas de reptiles en cautiverio, en la Región Metropolitana en Chile. Para ello, se realizó una prueba de susceptibilidad antimicrobiana por el método de Kirby-Bauer y posteriormente, mediante la técnica de PCR, se buscaron 11 genes de resistencia en las cepas en análisis, independiente de su fenotipo. Dentro de los genes a detectar, 3 de ellos están asociados a resistencia a beta-lactámicos (blaTEM, blaOXA y blaPSE-1), 4 a resistencia frente a estreptomicina (aadA1, aadA2, strA y strB), 3 para resistencia a tetraciclinas (tet(A), tet(B), tet(C)) y un gen que confiere resistencia a cloranfenicol (cmlA). Se observó una elevada sensibilidad fenotípica, donde el 23,5% de las cepas fue resistente a estreptomicina. De las 34 cepas analizadas, sólo se detectó el gen blaTEM en un 61,7%. El resto de las cepas resultaron negativas a la detección de los otros genes en análisis. La alta sensibilidad detectada puede deberse a fenómenos de curación plasmidial, mutaciones cromosomales, regulación de la expresión génica, entre otros, como mecanismo de restauración del fitness bacteriano en cepas conservadas en un medio carente de presión selectiva. Se concluye que las cepas analizadas presentan elevada sensibilidad fenotípica frente a beta-lactámicos, tetraciclinas, cloranfenicol y estreptomicina, encontrando sólo cepas portadoras del gen blaTEM. / Antimicrobial resistance is a phenomenon of great importance worldwide because of its impact on both human and animal health and the economic consequences it generates. Among resistant bacteria is Salmonella spp., worldwide distributed pathogen, usually transmitted by food, but also by direct or indirect contact with animal reservoirs. Within these, reptile become relevant because they are asymptomatic carriers of the bacteria, forming a reservoir that increasingly becomes more important due to the growing popularity as pets in today's families. In Chile there are few studies on antimicrobial resistance in strains of Salmonella spp. isolated from reptiles that associated genes to phenotypic resistance, reason why the aim of this study points to the detection of antimicrobial resistance genes in strains of Salmonella spp. isolated from reptiles in captivity, in Región Metropolitana in Chile. For this, an antimicrobial susceptibility test, by Kirby-Bauer method was performed and subsequently, by PCR, 11 resistance genes were searched in strains tested, regardless of their phenotype. Among genes to detect, 3 of them are associated with resistance to beta-lactam (blaTEM, blaOXA and blaPSE-1), 4 to resistance to streptomycin (aadA1, aadA2, strA and strB), 3 for tetracycline resistance (tet(A), tet(B), tet(C)) and a gene conferring chloramphenicol resistance (cmlA). High phenotypic susceptibility was observed, where 23,5% of the strains were streptomycin resistant. Of the 34 strains tested, only blaTEM gene was detected in 61,7%. The remaining strains were negative for detection of the other genes analyzed. High sensitivity detected may be due to a phenomenon of plasmidial healing, chromosomal mutations, gene expression regulation, among others, as a mechanism for restoring the bacterial fitness of strains preserved in a medium lacking of selective pressure. It is concluded that strains tested possess high phenotypic sensitivity to beta-lactams, tetracyclines, chloramphenicol and streptomycin, finding strains carrying only the blaTEM gene.

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