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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.

Chromosomal variation in Nucella lapillus (L.) and other muricid gastropods

Pascoe, Philip Lionel January 2002 (has links)
The Robertsonian polymorphism (numerical change in the chromosome complement by centric fusion or fission) in the dog-whelk (Nucella lapillus, Mollusca: Gastropoda) has been known and studied sporadically for almost 50 years. However, the possible causes, consequences and proposed correlations of this phenomenon remain enigmatic. Nucella lapillus (2n = 26 to 36), has undergone a marked reduction in chromosome number from its ancestral form; most other muricid species have a diploid chromosome number in the range 2n = 60- 70. Correlations have been proposed between chromosome number (or karyotype) and habitat (wave exposure), and also directly or indirectly with allozymes, shell shape and physiology. However, firm conclusions are lacking due to either, insufficient knowledge of the karyotypes in the populations studied, or the fact that any correlations are not consistent throughout the broad geographic range. This study reviews all the past research on the chromosomal polymorphism in N. lapillus, advances the karyology of this species by successfully labelling individual chromosomes through silver-staining of nucleolar organizer regions (NORs) and fluorescence in situ hybridisation (FISH) with rDNA and telomeric probes, and proposes a new system of nomenclature for this polymorphism. Knowledge of the geographic variation in chromosome number and karyotype is advanced by studying around 70 populations throughout the range of N. lapillus (mainly in the UK, but also the USA and northern and southern Europe). Evidence is shown that, (1) the polymorphism is far more widespread geographically than was previously thought; (2) more than five pairs of metacentric chromosomes are involved in the Robertsonian polymorphism; and (3) inversions also occur in some populations. Putative links between chromosomal polymorphism in N. lapillus and Darwinian fitness are reviewed in the light of the new findings and more recent work on other species; data are presented on fecundity, fertility, inter- and intra-individual variation in karyotype, selection within populations (adults v. embryos, homo- v. heterozygotes) and a possible genetic/karyotypic link with phenotype (Dumpton syndrome, a reproductive abnormality). Cytogenetic records for other muricids are also reviewed and karyotypes and chromosome lengths of four other species (Ocenebra erinacea, Thais haemastoma, Murex trunculus, Ocinebrina aciculata) are recorded for the first time. Genome size (DNA content) of 8 species of muricid, including the 2n=26 and 2n=36 forms of N. lapillus, are determined by Feulgen densitometry and compared in the context of evolutionary studies on the family. Although chromosome number and haploid length in N. lapillus has been reduced, its genome size is actually greater than all but one of the other muricids studied, and consequently has a much higher DNA packing ratio (>13000). Whether the chromosomal variation in N. lapillus represents polymorphism, polytypy, or speciation in progress remains unresolved, but substantial advances have been made in this dissertation and the required direction and focus for future work are clarified.

Multi-host pathogens and carnivore management in southern Africa

Alexander, KA, McNutt, JW, Briggs, MB, Standers, PE, Funston, P, Hemston, G, Keet, D, Van Vuuren, M 25 November 2008 (has links)
Abstract A retrospective serosurvey of multi-host feline and canine viruses among carnivore species in southern Africa (n = 1018) identified widespread pathogen exposure even in remote protected areas. In contrast to morality experienced in East African predators, canine distemper virus (CDV) infection among African wild dogs (Lycaon pictus) in Botswana was not associated with identifiable change in pup survivorship or disease related mortality of adults. A disease outbreak of unknown aetiology occurred in the same population over 4 weeks in 1996. Outbreak boundaries coincided with ecotones, not the spatial distribution of contiguous packs, highlighting the potential importance of landscape heterogeneities in these processes. Direct management of pathogens in domestic animal reservoirs is complicated by the apparent complexity of pathogen maintenance and transmission in these large systems. Conservation effort should be focused at securing large metapopulations able to compensate for expected episodic generalist pathogen invasion and attention directed to addressing underlying causes of population depression such as habitat loss and wildlife conflict.

Evaluation of epidural morphine and incisional bupivacaine for analgesia following hemilaminectomy in the dog

Horowitz, Farrah B. 23 June 2009 (has links)
A blind, placebo â controlled clinical trial was performed to evaluate the postoperative analgesic effect of topically administered, intraoperative, epidural morphine (Duramorphâ ¢) and intramuscular infiltration of the incision site with bupivacaine prior to closure of the skin in dogs undergoing hemilaminectomy for Hansen type I Intervertebral Disk Disease (IVDD). Thirty-three dogs were randomly allocated into four treatment groups: epidural Duramorphâ ¢ with incisional bupivacaine (DUR/BUP), epidural saline with incisional bupivacaine (SAL/BUP), epidural Duramorphâ ¢ with incisional saline (DUR/SAL), and epidural saline with incisional saline (SAL/SAL). All dogs were premedicated with a standard protocol and were anesthetized with propofol and isoflurane. After surgery, scores were assigned using a visual analog scale (VAS) for both pain and sedation and a composite pain scale (CPS). In addition, a von Frey anesthesiometer was used to determine pain thresholds at 1 cm and 3 cm from the surgical incision line (primary hyperalgesia) as well as on the lateral aspect of the stifle (secondary hyperalgesia). Assessments were carried out at fixed intervals over the 48 hour postoperative period. Significant differences were found between those groups treated with the epidural Duramorphâ ¢ and those that received epidural saline. Those dogs in the DUR/BUP and DUR/SAL groups exhibited lower von Frey pain thresholds and higher VAS and CPS scores than the SAL/BUP and SAL/SAL groups. The administration of bupivacaine had no significant effect on any measured outcome. The authors conclude that topically administered epidural Duramorphâ ¢ and intramuscular incisional bupivacaine do not enhance analgesia following hemilaminectomy in the dog. / Master of Science

History and consequence of keystone mammal eradication in the desert grasslands : the Arizona black-tailed prairie dog (Cynomys ludovicianus arizonensis) /

Oakes, Claudia Lea, January 2000 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 366-391). Available also in a digital version from Dissertation Abstracts.

Establishing genetic and physiological baselines for the black-tailed prairie dog (Cynomys ludovicianus)

Biggs, Cindy Dawn. Beitinger, Thomas L., January 2007 (has links)
Thesis (Ph. D.)--University of North Texas, May, 2007. / Title from title page display. Includes bibliographical references.

Feeding ecology and carrying capacity of a reintroduced pack of African wild dogs in a relatively small, fenced reserve.

Niemann, Sophie Mary. January 2010 (has links)
Reintroduction has been used successfully as a tool to restore declining populations of many threatened species. However, the lack of detailed evaluations of past reintroduction attempts has hindered a priori planning of management actions to achieve conservation goals. The metapopulation approach resulted in the most extensive and successful reintroduction efforts of the African wild dog (Lycaon pictus) in South Africa, but the approach was only recently evaluated by Gusset et al. (2008). For future reintroduction attempts to be successful on relatively small reserves, extensive evaluations are needed. Particular focus on feeding behaviour and impact on prey populations is essential to predict sustainability and carrying capacities in these areas for the African wild dog. A small reintroduced population of African wild dogs (pack number varying from 3 to 13 during the study period) were studied in the Karongwe Game reserve (79 km2) between January 2002 and January 2004. Fourteen prey species were identified: impala (Aepyceros melampus, 60 %) was the most dominant prey followed in descending order by bushbuck (Tragelaphus scriptus, 7.4 %), waterbuck (Kobus ellipsiprymnus, 4.9 %), warthog (Phacochoerus aethiopicus, 4.7 %), kudu (Tragelaphus strepsiceros, 4.4 %), and grey duiker (Sylvicapra grimmia, 4.4 %). Generally, prey were included in the diet in relation to abundance, and the dogs were not rate maximizing foragers but, unlike the findings of previous studies, were opportunistic feeders. The fences and angles in the fence, were used to assist hunting, but only for medium sized prey, impala and bushbuck, which were killed significantly more than expected along the fence line. A predictive prey preference model was then tested, but the model did not account for possible differences in feeding behaviours and prey preferences found in this, nor another study from the small Shambala Game Reserve. The model had limited accuracy as a predictive tool for proposed reintroductions into relatively small reserves. Models which can predict carrying capacity and minimum area requirements were also tested. Large variation and low numbers were predicted, which conflicted with social requirements needed for the survival of the population; further the models did not account for interspecific competition nor simultaneous depletion of prey by other guild predator. If the metapopulation approach is to continue to be successful and sustainable, more detailed evaluations of reintroductions of African wild dog on relatively small, fenced reserves are needed to determine the impact of these dogs on prey populations, and to determine if African wild dog feeding behaviour does differ for these areas in comparison to previously described open systems. With this information, more appropriate protocols regarding reintroduction and management can then be developed, thereby meeting one goal of management and conservation for the African wild dogs and their coexisting prey populations, and which can be used as a model for managing other large predators. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2010.

Verifying parentage and gender of domestic dog conceptuses using microsatellites

Steckler, Daniela 21 December 2010 (has links)
Parentage testing in the domestic dog is finding increasing application for dog breed registries as well as in research. The aim of parentage verification is the correct assignment of both parents to the offspring. For accurate parentage verification informative microsatellite markers have to be identified. More powerful models to study artificial insemination in bitches will be possible if the paternity and gender of early dog conceptuses can be determined. The amelogenin gene locus has been used in bovine day six to day seven embryos for early gender determination but no research has been done on early conceptuses of the domestic dog. The aim of the current study was to establish an accurate method for parentage and gender determination from domestic dog conceptuses during early pregnancy in a multi-sire insemination trial. Semen from 10 male dogs was used in each of 12 females for artificial insemination. Blood and uterine tissue for DNA extraction was collected from males and females, and embryonic material was collected after ovariohysterectomy between 16 and 30 days after the onset of cytological dioestrus. Twenty-three microsatellite markers were used for parentage verification, and the amelogenin gene locus for gender determination. Mean observed heterozygosity, mean expected heterozygosity (HExp), and mean PIC were high (0.6753, 0.6785, and 0.628, respectively). There were 66 conceptuses. In two, neither parentage nor gender could be established because their tissue samples were contaminated. Parentage could be assigned by CERVUS 3.0.3 in 42 out of 64 of the cases (66%) without difficulty. Another 33% of the cases (21 out of 64) could be resolved using the number of exclusions, LOD scores or manual verification of genotyping errors. In one conceptus, paternity could not be established because its sire may have been either of two siblings. The gender of the female and male dogs was successfully confirmed using the amelogenin gene locus. The gender of the conceptuses was determined using the amelogenin gene locus (50% male, 50% female) but not confirmed by another method of gender determination such as karyotyping. As shown in the current study, the panel of 24 microsatellite markers used provides high information content suitable for parentage verification in multi-sire litters, as well as gender determination of early conceptuses. / Dissertation (MSc)--University of Pretoria, 2010. / Production Animal Studies / unrestricted

Níveis de IgG anti-Leishmania e perfil de citocinas em cães machos e fêmeas assintomáticos naturalmente infectados por Leishmania (L.) Chagasi /

Dossi, Ana Cláudia Silva. January 2006 (has links)
Orientador: Valéria Marçal Felix de Lima / Banca: Rosangela Zacarias Machado / Banca: Alexandre Barbosa Reis / Resumo: O cão é o principal reservatório da Leishmania (Leishmania) chagasi, o parasita responsável pela Leishmaniose Visceral (LV) nas Américas. Na (LV) estudos em modelos experimentais, têm mostrado diferenças na resposta imunológica entre macho e fêmea. Na (L VC) tais estudos, não foram realizados. Este trabalho investigou em cães assintomáticos machos e fêmeas, naturalmente infectados por Leishmania (L.) chagasi, os níveis séricos de IgG contra antígenos totais de Leishmania, o nível de IL-10 e IFN-y, no sobrenadante do extrato do baço e fígado, e a citocina regulatória TGF-j3 no sobrenadante do extrato do baço e fígado, e sua produção natural no sobrenadante de cultura de células esplênicas. Os níveis de anticorpos anti-L. (L.) chagasi da classe IgG nos cães assintomáticos machos e fêmeas, não apresentaram diferença significativa entre o sexo. O nível de IL-10 mostrou-se elevado, no sobrenadante do extrato do fígado em cães infectados machos e fêmeas assintomáticos e apresentou dominância marcante em relação às outras citocinas. O nível do TGF-j3 mostrou-se aumentado no extrato do baço. O nível de IFN-y no baço dos grupos avaliados foi quantitativamente menor que as citocinas IL-10 e TGF-B. diferindo do observado no fígado onde foi observado uma baixa produção de TGF-j3 em relação ao IFN-y. No baço, o IFN-y apresentou diferença significativa em fêmeas assintomáticas quando comparadas com os machos assintomáticos. A observação da predominância das citocinas TGF-j3 no baço, e IL-10 no baço e fígado, em modelo ex vivo, sugere uma polarização da resposta imunológica para o padrão Th2 em cães naturalmente infectados por Leishmania (L.) chagasi. / Abstract: The dog is the main reservoir of Leíshmanía (Leíshmanía) chagasí, the parasite responsible for Visceral Leishmaniasis (VL) in the Americas. Experimental studies on VL have shown differences in the immune response of males and females. Such studies have not been carried out on canine visceral leishmaniasis. This study investigated the seric levei of IgG against Leíshmanía total antigens, the levels of IL-10 and IFN-y in the supernatant of spleen and liver extracts, the regulatory cytokine TGF-131 in the supernatant of spleen and liver extracts, and its natural production in the supernatant of spleen cell culture, in male and female asymptomatic dogs naturally infected by Leíshmanía (L.) chagasi. The levels of anti-L. (L.) chagasí IgG antibodies in male and female asymptomatic dogs did not differ significantly between the sexes. IL-10 levei was high in the supernatant of the liver extract of male and female asymptomatic infected dogs and predominated over the other cytokines. TGF-131 levei was increased in the spleen extract. The levei of IFN-y in the spleen of the group evaluated was quantitatively lower than the IL-10 and TGF-131 cytokine levels, different from what was observed in the liver, where a low productíon of TGF-131 was observed when compared to IFN-y. In the spleen, IFN-y presented a significant difference in the asymptomatic females when compared to the asymptomatic males. The observation of a predominance of TGF-131 cytokines in the spleen and of IL-10 in the spleen and liver of an ex vívo model suggests a polarization of the immune response towards the Th2 pattern in dogs naturally infected by Leíshmanía (L.) chagasí. / Mestre

Ladra Seguro

Paniagua Palavicini , Gustavo Alonso 01 December 2019 (has links)
En el mundo de hoy tener una mascota es muy frecuente en todos los hogares. En Lima Metropolitana, 1.37 millones de hogares tiene alguna mascota en casa, esto representa el 55% de hogares limeños, y se estima que para el 2021 la cifra llegará a los 1.45 millones (Ipsos, 2016). Nuestra investigación nos permite conocer que las personas que tienen un perro, por lo general consideran al can como un miembro más del hogar, sin embargo el cuidado hacia las mascotas a veces no se puede dar por la falta de tiempo que presentan sus dueños y que incluso impide que puedan salir a pasear a sus mascotas por lo menos una vez al día. Por ello, si no ocurre esto los perros sufren, de estrés y de enfermedades somáticas que se desencadenan, además de problemas de conducta que a la larga acarrean problemas para los dueños y sus hogares (Mármol, 2016). Esta coyuntura da pie a que se cree “Ladra Seguro” proyecto que busca formalizar un servicio de paseadores de perros, apoyándose en herramientas tecnológicas de última generación como un aplicativo que brinde a los dueños de mascotas un servicio seguro y de buena calidad. Adicionalmente, se desarrollará un adiestramiento que permita a los caninos obtener todo el ejercicio y cuidado que requieran durante el tiempo que están fuera de su hogar. / In today's world, having a pet is very common in every home. In Metropolitan Lima, 1.37 million households have a pet at home, this represents 55% of Lima households, and it is estimated that by 2021 the figure will reach 1.45 million (Ipsos, 2016). Our research allows us to know that people who have a dog, generally consider the dog as another member of the household, however care for pets sometimes cannot be given due to the lack of time that their owners present and that they even prevent them from being able to walk their pets at least once a day. Therefore, if this does not happen, dogs suffer from stress and somatic diseases that are triggered, in addition to behavior problems that in the long run cause problems for the owners and their homes (Mármol, 2016). This situation gives rise to the creation of "Safe Barks", a project that seeks to formalize a service for dog walkers, relying on state-of-the-art technological tools such as an application that provides pet owners with a safe and good quality service. In addition, a training will be developed that allows the canines to obtain all the exercise and care they require during the time they are away from home. / Trabajo de investigación

Pathophysiology and evaluation of food intolerance to soy using an atopic dog model

Kennis, Robert Allen 30 September 2004 (has links)
The purpose of the study was to test the hypothesis that dogs sensitized to soy antigen would produce significantly greater amounts of antigen specific IgE antibody compared to a control population before and after challenges with soy, hydrolyzed soy, and non-soy diets. Further, we sought to evaluate important allergenic components of soy using Western blot analysis. Lastly, absorption and mucosal function testing using inert sugars were evaluated for our sensitized and non-sensitized controls. Eight dogs (6 female, 2 male) were sensitized to whole soy using an established protocol. Seven dogs (3 female, 4 male) roughly age matched were used as controls. The dogs were randomly split into three groups. All dogs were fed an elimination diet of egg and Brewer's rice for six weeks. Samples were collected and each group was fed a diet of soy and rice flour, hydrolyzed soy and rice flour, or corn and rice flour for three weeks. Samples were collected and each group was fed the elimination diet followed by challenge with each of the diets. Serum was collected and stored for allergen specific IgE semi-quantitation and Western blot analysis using whole soy fractionated into globulin and whey components. A solution of monosaccharide and disaccharide sugars was administered in a volume determined by weight. Six hours after administration the dogs were catheterized and the entire urine volume was collected for measurement of sugar recovery by high pressure chromatography, followed by pulsed amphometric detection. There was a statistically significant difference in serum IgE between sensitized and control dogs after the elimination diet, and also for each of the challenged diets. There were differences detected by Western blot analysis for allergens within the soy globulin and whey fractions for sensitized dogs compared to control dogs. There were no significant differences between sensitized and control dogs for sugar recovery for any of the diets. We conclude that although there were significant differences in measurable IgE between sensitized and control dogs, we were unable to differentiate these groups using gastrointestinal mucosal permeability and function testing.

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