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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.
1

Rough leucine auxotrophic strains of <i>Brucella</i> expressing <i>Salmonella</i> flagellin C conjugated gonadotropins, an immunocontraceptive brucellosis vaccine for feral swine population control

Waldrop, S. Grant January 2020 (has links)
Brucellosis, caused by Gram-negative bacteria of the genus <i>Brucella</i>, is a zoonotic disease with global impacts on human, livestock, and wildlife health. Around 500,000 cases of human brucellosis are reported by the World Health Organization annually. Even though brucellosis has been eradicated from domestic livestock in the United States of America, the causative bacterial pathogen is still present in elk, bison, and feral swine. With the growth of free-range farming, domestic livestock and wildlife populations come into close contact, spreading the disease. Feral swine interactions are of particular concern. They carry a number of zoonotic diseases including brucellosis. As there is no commercial vaccination protocol to prevent brucellosis in wildlife and swine, interactions with these populations are especially dangerous for public health. Feral swine population is increasing nationwide even with the current population control practices. There is an urgent need for efficient control of feral swine and preventing the spread of brucellosis. To aid in the prevention of the spread of feral swine across the USA, immunocontraceptives have been employed. Over the years several candidates have been tested, but the search for the perfect vaccine is still ongoing. The monumental task includes reversibly preventing one of life’s most basic necessities, reproduction, through an oral route with no effect on non-target species. One way that science is tackling both of these threats at once is through dual-purpose vaccines. Dual-purpose vaccines produce an immune response that targets two different pathogens, or in this case a pathogen and reproductive hormones. In the effort to produce this vaccine, more knowledge was needed in regards to <i>B. neotomae</i>. This dissertation showed that it has the ability to survive in a variety of cells from different species, in a similar manner to known virulent <i>Brucella</i> species. This is of concern when using <i>B. neotomae</i> as a vaccine, but it has also been shown that attenuated <i>B. neotomae</i> can provide protection against virulent <i>B. suis, B. abortus</i>, and <i>B. melitensis</i> challenge. This is a major finding in the effort towards a universal brucellosis vaccine. After genetic manipulation, cell culture assays, and mouse trials, several leucine auxotrophic <i>B. neotomae</i> and <i>B. abortus</i> strains show promise in the effort towards a dual-purpose vaccine. Strains of <i>B. neotomae</i> <i>ΔwboA ΔleuB</i> pNS4-trcD-fliC-Gonadotropins were discontinued in this effort towards a brucellosis immunocontraceptive dual-purpose vaccine due to lethality issues in mice. These stability and lethality issues are still under investigation. Instead, a proven stable strain of <i>B. abortus</i> RB51 (a USDA approved cattle vaccine) was used to investigate its effects on fertility in mice when expressing fliC-Gonadotropins. Strains <i>B. abortus</i> RB51 ΔleuB pNS4-trcD-fliC-porcineFSHβ (RB51LFSHβ) and <i>B. abortus</i> RB51 ΔleuB pNS4-trcD-fliC-GnRH (RB51LGnRH) confer reduced fertility characteristics in both male and female purpose bred mice. Strain RB51 ΔleuB has also been shown to protect against virulent <i>B. abortus</i> challenge in the literature. These findings warrant further investigation to determine the efficacy of these vaccine strains in swine as an oral vaccine. Ultimately, their ability to prevent brucellosis, while causing immunocontraception needs to be determined in feral swine. / Ph.D. / While brucellosis has been eradicated from domestic livestock in the United States, the causative agent is still present in wildlife like elk, bison, and feral swine. The interactions between these infected wildlife populations with domestic livestock and human populations pose a great health risk. Many tools are employed to mitigate these interactions including vaccination programs and population management. In particular, the feral swine population has proven difficult to control. It has quadrupled in the past ten years and continues to expand nationwide, making their population control an important national objective. Furthermore, feral swine are known carriers of zoonotic diseases, including hemorraghic colitis, leptospirosis, trichinosis, swine influenza, and brucellosis. Many cases of these diseases in humans have been traced back to interactions with feral swine. The current population control practices have failed to minimize the $1.5 billion of damage they cause to the agricultural industry per year. Thus, there is a need to effectively control the feral swine population and prevent the spread of zoonotic diseases like brucellosis. Rough leucine auxotrophic strains of <i>Brucella</i> expressing gonadotropin releasing hormone (GnRH) or porcine follicle stimulating hormone beta subunit (FSH) conjugated to <i>Salmonella</i> fliC show promise. They have been shown to provide protection from virulent Brucella strain challenge and reduce fertility characteristics in mice. Their effectiveness as an immunocontraceptive for feral swine management, while reducing the spread of brucellosis needs to be tested in swine. These vaccine strains [<i>B. abortus</i> RB51 ΔleuB pNS4-trcD-fliC-porcineFSHβ (RB51LFSHβ), <i>B. abortus</i> RB51 ΔleuB pNS4-trcD-fliC-GnRH (RB51LGnRH) and <i>B. neotomae ΔwboA ΔleuB</i> pNS4-trcD-fliC-GnRH (BNWLGnRH)] could pave the way for effective novel immunocontraceptive tools to be used in wildlife management.
2

Distribuição do maracanã-verdadeiro Primolius maracana (psittacidae): preferência de hábitat e fatores que influenciam na manutenção de sua populações remanescentes. / Distribution of blue-winged macaw primolius maracanã: habitat preferences and factors affecting the persistence of its remaining populations.

Nunes, Maria Flávia Conti 02 October 2003 (has links)
O Maracanã- verdadeiro é um psitacídeo vulnerável a extinção, por estar havendo redução de suas populações em diferentes partes de sua área de ocorrência. Foi realizada uma revisão sobre a distribuição, histórica e atual, e o estatus da espécie através de dados de espécimes de museus e literatura. Foram reunidos 176 registros de localização do maracanã e comparadas as distribuições histórica e atual. Constatou-se, principalmente, uma contração dos limites ao sul da distribuição histórica da espécie. Dessa maneira, foi avaliado se nessa região a ocorrência do maracanã está associada a características da composição e estrutura da vegetação. Dados de ocorrência atual da espécie foram relacionados com a localização geográfica e índices de paisagem de 54 localidades, através da análise de regressão logística. Verificou-se que o “total de cobertura vegetal da paisagem" foi a única característica de paisagem significativamente relacionada com a ocorrência do maracanã (p<0,01), porém o poder explicativo da variável foi baixo. A variável “latitude" também foi altamente significativa (p<0,001) e não foi relacionada com nenhuma das métricas de paisagem analisadas. Isso sugere a existência de um outro fator não avaliado, com estrutura espacial em clina latitudinal, que está afetando as populações meridionais do maracanã. Foi também estudado o padrão de ocorrência do maracanã em escala local, no entorno da Estação Ecológica de Caetetus (2178 ha). Essa reserva está imersa em um mosaico de paisagem constituído por pequenos remanescentes florestais que podem ser importantes para a conservação da espécie. Foram amostradas 36 destas áreas remanescentes, através do método de contagens em pontos estratégicos. Cada fragmento obteve um índice de visitas por maracanã que foram relacionados as suas características espaciais, através da análise de regressão linear. As características das paisagens no entorno dos remanescentes estudados explicaram mais a variação da freqüência de visitas pelo maracanã que as características dos próprios fragmentos. As visitas dos maracanãs foram diretamente relacionadas com a “distância do fragmento até a cidade mais próxima" (p<0,05) e o “tamanho do remanescente" (p<0,05), e inversamente relacionado a “distância mínima do fragmento até um dormitório conhecido de maracanã" (p<0,01) e “distância mínima do fragmento até a E.E. dos Caetetus" (p<0,05). Todas essas análises indicaram que a conservação da paisagem como um todo parece ser fundamental para manutenção de populações do maracanã, em escala local e regional. Porém deve-se levar em conta a área dos fragmentos e sua configuração espacial, investindo esforços para a conservação das áreas de dormitórios. / The blue-winged macaw is a vulnerable psittacidae, which has been suffering a rapid reduction of its populations in different parts of its occurrence. Thus, it was carried a detailed revision on the, historical and current, distribution and estatus of the species through using literature and specimens in museums data. We gathered 176 records of blue-winged macaw sites and compared its historical and current distributions. We verified a range contraction in the south limit of blue-winged macaw’s historical occurence. In this way, we evaluated if, in this zone, the blue-winged macaw’s occurrence is correlated to composition and structure of residual vegetation. The current occurrence of the species was related to geographic coordinates and landscape indices of 54 localities, through the logistic regression analysis. The "total of vegetal cover of the landscape" was the only feature of the landscape significantly related to blue-winged macaw’s occurrence (p<0,01), however its explicatory power was very low. The "latitude" was highly significant to predict blue-winged macaw’s occurrence (p<0,001), and also was not related to any analyzed landscape metric. This suggests the existence of another non-evaluated factor, with spatial structure highly related to latitude, affecting the southern populations of blue-winged macaw. Also we studied the occurrence pattern of blue-winged macaw in local scale, around of Caetetus Ecological Station (2178 ha). This reserve is placed in a mosaic of landscape, consisting of small remnants of native vegetation that may have some value to the specie’s maintenance. We sampled 36 of these remaining areas through the method of countings in advantage points. Each remnant got a "blue-winged macaw’s visit index" that was related to spatial remnants features and its surrounding landscape, through the linear regression model. The landscape features around of the fragments explained more the variation of the bluewinged macaw’s visit index than the features of the fragments itself. The "index of visits of maracanãs" was directly related to "distance to the closest city" (p<0,05) and to "remnant size" (p<0,05), and inversely related to "distance to the closest known roost of blue winged macaw " (p<0,01) and "shortest distance to the Caetetus Ecological Station" (p<0,05). All these analyses indicate that the conservation of the landscape as a whole seems to be critical for the maintenance of blue-winged macaw’s populations, in local and regional scale. However the size of the remnants and its spatial configuration must be taken in account, besides the efforts for the conservation of the roost sites.
3

Distribuição do maracanã-verdadeiro Primolius maracana (psittacidae): preferência de hábitat e fatores que influenciam na manutenção de sua populações remanescentes. / Distribution of blue-winged macaw primolius maracanã: habitat preferences and factors affecting the persistence of its remaining populations.

Maria Flávia Conti Nunes 02 October 2003 (has links)
O Maracanã- verdadeiro é um psitacídeo vulnerável a extinção, por estar havendo redução de suas populações em diferentes partes de sua área de ocorrência. Foi realizada uma revisão sobre a distribuição, histórica e atual, e o estatus da espécie através de dados de espécimes de museus e literatura. Foram reunidos 176 registros de localização do maracanã e comparadas as distribuições histórica e atual. Constatou-se, principalmente, uma contração dos limites ao sul da distribuição histórica da espécie. Dessa maneira, foi avaliado se nessa região a ocorrência do maracanã está associada a características da composição e estrutura da vegetação. Dados de ocorrência atual da espécie foram relacionados com a localização geográfica e índices de paisagem de 54 localidades, através da análise de regressão logística. Verificou-se que o “total de cobertura vegetal da paisagem” foi a única característica de paisagem significativamente relacionada com a ocorrência do maracanã (p<0,01), porém o poder explicativo da variável foi baixo. A variável “latitude” também foi altamente significativa (p<0,001) e não foi relacionada com nenhuma das métricas de paisagem analisadas. Isso sugere a existência de um outro fator não avaliado, com estrutura espacial em clina latitudinal, que está afetando as populações meridionais do maracanã. Foi também estudado o padrão de ocorrência do maracanã em escala local, no entorno da Estação Ecológica de Caetetus (2178 ha). Essa reserva está imersa em um mosaico de paisagem constituído por pequenos remanescentes florestais que podem ser importantes para a conservação da espécie. Foram amostradas 36 destas áreas remanescentes, através do método de contagens em pontos estratégicos. Cada fragmento obteve um índice de visitas por maracanã que foram relacionados as suas características espaciais, através da análise de regressão linear. As características das paisagens no entorno dos remanescentes estudados explicaram mais a variação da freqüência de visitas pelo maracanã que as características dos próprios fragmentos. As visitas dos maracanãs foram diretamente relacionadas com a “distância do fragmento até a cidade mais próxima” (p<0,05) e o “tamanho do remanescente” (p<0,05), e inversamente relacionado a “distância mínima do fragmento até um dormitório conhecido de maracan㔠(p<0,01) e “distância mínima do fragmento até a E.E. dos Caetetus” (p<0,05). Todas essas análises indicaram que a conservação da paisagem como um todo parece ser fundamental para manutenção de populações do maracanã, em escala local e regional. Porém deve-se levar em conta a área dos fragmentos e sua configuração espacial, investindo esforços para a conservação das áreas de dormitórios. / The blue-winged macaw is a vulnerable psittacidae, which has been suffering a rapid reduction of its populations in different parts of its occurrence. Thus, it was carried a detailed revision on the, historical and current, distribution and estatus of the species through using literature and specimens in museums data. We gathered 176 records of blue-winged macaw sites and compared its historical and current distributions. We verified a range contraction in the south limit of blue-winged macaw’s historical occurence. In this way, we evaluated if, in this zone, the blue-winged macaw’s occurrence is correlated to composition and structure of residual vegetation. The current occurrence of the species was related to geographic coordinates and landscape indices of 54 localities, through the logistic regression analysis. The "total of vegetal cover of the landscape" was the only feature of the landscape significantly related to blue-winged macaw’s occurrence (p<0,01), however its explicatory power was very low. The "latitude" was highly significant to predict blue-winged macaw’s occurrence (p<0,001), and also was not related to any analyzed landscape metric. This suggests the existence of another non-evaluated factor, with spatial structure highly related to latitude, affecting the southern populations of blue-winged macaw. Also we studied the occurrence pattern of blue-winged macaw in local scale, around of Caetetus Ecological Station (2178 ha). This reserve is placed in a mosaic of landscape, consisting of small remnants of native vegetation that may have some value to the specie’s maintenance. We sampled 36 of these remaining areas through the method of countings in advantage points. Each remnant got a "blue-winged macaw’s visit index" that was related to spatial remnants features and its surrounding landscape, through the linear regression model. The landscape features around of the fragments explained more the variation of the bluewinged macaw’s visit index than the features of the fragments itself. The "index of visits of maracanãs" was directly related to "distance to the closest city" (p<0,05) and to "remnant size" (p<0,05), and inversely related to "distance to the closest known roost of blue winged macaw " (p<0,01) and "shortest distance to the Caetetus Ecological Station" (p<0,05). All these analyses indicate that the conservation of the landscape as a whole seems to be critical for the maintenance of blue-winged macaw’s populations, in local and regional scale. However the size of the remnants and its spatial configuration must be taken in account, besides the efforts for the conservation of the roost sites.
4

Land-use change, protected area effectiveness, and wildlife dynamics in post-Soviet European Russia

Sieber, Anika 30 May 2017 (has links)
Die Biodiversitätskrise des Anthropozäns wird vor allem durch vom Menschen bedingte Umweltveränderungen verursacht. Naturschutzgebiete sind ein globaler Eckpfeiler des Umweltschutzes und besonders wichtig für den Erhalt von Großsäugern. Fortschreitender menschlicher Einfluss sowie zunehmender Verlust und die Zerteilung von Lebensräumen innerhalb und außerhalb von Naturschutzgebieten beeinflussen deren Effektivität und Wert für den Umweltschutz stark, besonders in Zeiten sozioökonomischer und institutioneller Schocks mit reduzierten Ressourcen für den Umweltschutz. Der Zusammenbruch der Sowjetunion im Jahr 1991 war solch ein Schock und das Ziel dieser Doktorarbeit war es, besser zu verstehen, wie dieser Schock die Landnutzung, die Effektivität von Naturschutzgebieten und die Populationsdynamik von Wildtieren beeinflusst hat. Der europäische Teil Russlands bot sich deshalb als Untersuchungsgebiet an, da es eine vom Menschen stark beeinflusste Region ist, welche Lebensraum für Großsäuger aufweist sowie ein Netzwerk von Naturschutzgebieten besitzt, die über Langzeitdaten zur Biodiversität verfügen. Diese Doktorarbeit verwendete umfassende Datensätze und interdisziplinäre Ansätze, um die Veränderungen in Landnutzung, Jagddruck, Naturschutzgebieten, Lebensräumen und Populationsdynamiken von Wildtieren in post-sowjetischer Zeit zu beobachten und auszuwerten. Die Ergebnisse zeigen, dass der sozioökonomische und institutionelle Schock nach 1991 einen verringerten Landnutzungsdruck zur Folge hatte, bedingt durch die weit verbreitete Aufgabe von Landwirtschaft und generell abnehmende Raten von Waldeinschlag. Naturschutzgebiete spielten eine wichtige Rolle beim Schutz der Biodiversität und profitierten von vergrößerten Lebensräumen für Großsäuger. Wildtierpopulationsdynamiken waren in post-sowjetischer Zeit wesentlich beeinflusst von Landnutzungswandel und Jagddruck. Diese Forschungsergebnisse leisten einen wertvollen Beitrag zur Unterstützung des Biodiversitätsmonitorings. / The biodiversity crisis of the Anthropocene era is mainly caused by human-induced environmental changes such as land-use change and the overexploitation of wildlife. Protected areas are a cornerstone of the global conservation efforts and particularly important for preserving large mammals. Increasing human impact and continued loss and fragmentation of wildlife habitats inside and outside protected areas strongly affect their effectiveness and conservation value, especially during times of socio-economic and institutional shocks with reduced resources for nature conservation. The breakdown of the Soviet Union in 1991 was such a shock and the overall aim of this thesis was to contribute to a better understanding of how this shock affected land use, protected area effectiveness, and wildlife dynamics in European Russia. European Russia served as a representative area for such a study as it is a human-dominated region, which harbors large mammal species and a long-established network of scientific protected areas providing long-term biodiversity data. The overall aim of this thesis was assessed by using a broad range of data and interdisciplinary approaches to monitor and evaluate changes in land use and hunting pressure, protected areas, wildlife habitats, and species population dynamics in post-Soviet times. The results of this thesis revealed that the socio-economic and institutional shock after 1991 resulted in reduced land-use pressure due to widespread farmland abandonment and overall lowered rates of forest logging in European Russia. Protected areas played an important role in halting threats to biodiversity and benefitted from increased large mammals’ habitat within their zone of interaction. Wildlife dynamics were significantly affected by land-use change and hunting pressure in post-Soviet times. The findings of this thesis provide a valuable contribution to support biodiversity monitoring and overcome knowledge gaps on biodiversity conservation.

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