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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

Population dynamics and secondary production of the small copepods in the Menai Strait

Castellani, Claudia January 2001 (has links)
Measuring zooplankton standing stock and production is a central problem in marine biology since zooplankton, particularly copepods, link primary productivity to fisheries productivity. The aim of the present study was to determine the seasonal and annual variation in the standing stock and secondary production of the main calanoid copepod species found in the Menai Strait, eastern Irish Sea. The zooplankton survey was carried out between January 1996 and December 1997. In addition, the reproduction and the respiration rate of the dominant copepod species, T. longicornis, was investigated between 1996 and 1998 during field and laboratory experiments to study its population dynamics. The temperature during January through to April differed between years, with the winter 1996 being colder than that of 1997 and 1998. The timing of the spring phytoplankton bloom also differed between years with the Chla maximum in 1996 occurring -1 month later than in 1997 and 1998. T. longicornis produced eggs all year round with maximum carbon-specific egg production rates (EPR) of (-0.14 μg Egg-C jig fem. -C-1 day 1) coinciding with the spring phytoplankton bloom and minimum rates (-0.01 μg Egg-C μg fem. -C-1 day1) in winter. The pattern of natural EPR variability indicates that individual fecundity was positively related to female weight and food quantity (possibly constrained by food size or quality) and negatively related to tidal range (i. e. total suspended sediment). In all three years, the hatching success (% HS) of the eggs laid decreased by -80 % during peak phytoplankton production and was significantly negatively correlated (r = -0.47, p<0.05, d. f. = 96) with ambient Chl-a concentration. These non-hatching eggs could have been diapause eggs. The respiration rate of T. longicornis varied during the year increasing both with body weight and with temperature. The metabolic daily energy loss of an adult copepod account for between 4% and 8% of its body carbon (winter and summer respectively). The seasonal pattern of copepod abundance and species composition was typical of temperate coastal areas. The seasonal variation in the copepod community (by number and biomass) showed T. longicornis to be the most abundant in spring, Centropages hamatus and Acartia clausi in summer and Pseudocalanus sp. in autumn and winter. Maximum total copepod standing stock occurred during the spring phytoplankton bloom and minimum between autumn and winter with total annual standing stock in 1996 (618 mg-C m 3) being -4 times lower than in 1997 (2530 mg-C m-3). Stage specific, copepod cephalothorax lengths varied with season and in most cases were negatively correlated with temperature. Individual weights and abundance of the copepods, together with measures of temperature, were used to predict weight specific growth and production rates using published empirical relationships. Calanoid copepod total annual production varied between 37-160 mg-C M-3 yr 1 for 1996 and 1997 respectively with T. longicornis accounting for -50 % of the total followed by C. hamatus (-25 %), A. clausi (-20 %) and Pseudocalanus sp. (5 %). Annual carbon flow in the Menai Strait was estimated from copepod production with measures of primary production, production of bacteria (previous study) and ciliates at this site. It is suggested that since the spring increase in T. longicornis population could not be attributed to the EPR of over-wintering females alone, the excess of copepods may either originate from the hatching of resting eggs during winter or from transport of animals from southern regions. If resting eggs were implicated in copepod population dynamics the annual variation in copepod standing stock may be controlled by climate change through differential hatching rate of resting eggs in winter.
2

Proteção cruzada contra a infestação de Rhipicephalus (Boophilus) microplus em bovinos vacinados com a glutationa-s-transferase recombinante de Haemaphysalis longicornis

Parizi, Luis Fernando January 2010 (has links)
Os carrapatos Rhipicephalus (Boophilus) microplus e Haemaphysalis longicornis são ectoparasitas hematófagos que infestam bovinos. O uso de vacinas anticarrapato tem mostrado ser uma estratégia alternativa promissora para o controle desses parasitos. As glutationa-S-transferases (GSTs) pertencem a uma família de enzimas multifuncionais presentes em organismos animais e vegetais, e, entre suas funções, pode-se destacar o transporte intracelular, a participação em processos digestivos, a síntese de prostaglandinas, a detoxificação de substâncias tóxicas e a proteção contra o estresse oxidativo. Em trabalhos anteriores, verificou-se em camundongos que a GST de H. longicornis (rGST-Hl) é mais imunogênica que a GST de R. microplus (rGST-Bm). O objetivo do presente estudo foi investigar a proteção cruzada conferida pela imunização de bovinos com a rGST-Hl frente a uma infestação de R. microplus. Por Western blot, verificou-se que os bovinos vacinados com a rGST-Hl apresentaram um aumento nos níveis de anticorpos anti-rGST-Hl, os quais foram capazes de reconhecer a GST-Bm nativa de extratos de larva, ovário e glândula salivar. Posteriormente, os bovinos foram infestados com 20.000 larvas de R. microplus. O percentual de proteção conferido foi calculado em função da variação entre os grupos tratados e controle, em relação ao número e peso de carrapatos que terminaram a alimentação, a capacidade de postura e a fertilidade dos ovos. O grupo dos bovinos vacinados com rGST-Hl mostrou uma redução de 53% e 52% no número e no peso de teleóginas, respectivamente. A postura de ovos e a eclodibilidade apresentaram uma redução no grupo vacinado de 0,6% e 8%, respectivamente. A eficácia total contra a infestação de R. microplus foi de 57%, quando comparado ao grupo controle. / The ticks Rhipicephalus (Boophilus) microplus and Haemaphysalis longicornis are hematophagous ectoparasites that infest bovines. Vaccine has been considered one of the most promising methods for the control of these parasites. Glutathione Stransferases (GSTs) enzymes are present in animal and vegetal organisms and are important in intracellular transport, digestive process, synthesis of prostaglandins, detoxification and protection against oxidative stress. In a previous study with mice we showed that H. longicornis GST (rGST-Hl) is more immunogenic than R. microplus GST (rGST-Bm). The objective of the present study was to investigate the crossprotection against R. microplus infestation in bovine vaccinated with rGST-Hl. By Western blot, the immunized bovines showed an increase in antibodies anti-rGST-Hl. The native GST-Bm in larvae, ovary and salivary gland were recognized by sera of bovines immunized with rGST-Hl, indicating that the antibodies induced by rGST-Hl immunization recognize native R. microplus GSTs. The bovines were challenged with 20,000 larvae of R. microplus. Protection was calculated by variation in number and weight of fully engorged ticks, egg laying capacity and egg fertility. The bovines vaccinated with rGST-Hl showed a reduction of 53% and 52% in number and weight of engorged ticks, respectively. Egg laying capacity and egg fertility of ticks from vaccinated bovines were respectively 0.6% and 8% lower, as compared to ticks from control animals. The overall efficacy ratio against R. microplus was 57.03%, as compared with the control group.
3

Proteção cruzada contra a infestação de Rhipicephalus (Boophilus) microplus em bovinos vacinados com a glutationa-s-transferase recombinante de Haemaphysalis longicornis

Parizi, Luis Fernando January 2010 (has links)
Os carrapatos Rhipicephalus (Boophilus) microplus e Haemaphysalis longicornis são ectoparasitas hematófagos que infestam bovinos. O uso de vacinas anticarrapato tem mostrado ser uma estratégia alternativa promissora para o controle desses parasitos. As glutationa-S-transferases (GSTs) pertencem a uma família de enzimas multifuncionais presentes em organismos animais e vegetais, e, entre suas funções, pode-se destacar o transporte intracelular, a participação em processos digestivos, a síntese de prostaglandinas, a detoxificação de substâncias tóxicas e a proteção contra o estresse oxidativo. Em trabalhos anteriores, verificou-se em camundongos que a GST de H. longicornis (rGST-Hl) é mais imunogênica que a GST de R. microplus (rGST-Bm). O objetivo do presente estudo foi investigar a proteção cruzada conferida pela imunização de bovinos com a rGST-Hl frente a uma infestação de R. microplus. Por Western blot, verificou-se que os bovinos vacinados com a rGST-Hl apresentaram um aumento nos níveis de anticorpos anti-rGST-Hl, os quais foram capazes de reconhecer a GST-Bm nativa de extratos de larva, ovário e glândula salivar. Posteriormente, os bovinos foram infestados com 20.000 larvas de R. microplus. O percentual de proteção conferido foi calculado em função da variação entre os grupos tratados e controle, em relação ao número e peso de carrapatos que terminaram a alimentação, a capacidade de postura e a fertilidade dos ovos. O grupo dos bovinos vacinados com rGST-Hl mostrou uma redução de 53% e 52% no número e no peso de teleóginas, respectivamente. A postura de ovos e a eclodibilidade apresentaram uma redução no grupo vacinado de 0,6% e 8%, respectivamente. A eficácia total contra a infestação de R. microplus foi de 57%, quando comparado ao grupo controle. / The ticks Rhipicephalus (Boophilus) microplus and Haemaphysalis longicornis are hematophagous ectoparasites that infest bovines. Vaccine has been considered one of the most promising methods for the control of these parasites. Glutathione Stransferases (GSTs) enzymes are present in animal and vegetal organisms and are important in intracellular transport, digestive process, synthesis of prostaglandins, detoxification and protection against oxidative stress. In a previous study with mice we showed that H. longicornis GST (rGST-Hl) is more immunogenic than R. microplus GST (rGST-Bm). The objective of the present study was to investigate the crossprotection against R. microplus infestation in bovine vaccinated with rGST-Hl. By Western blot, the immunized bovines showed an increase in antibodies anti-rGST-Hl. The native GST-Bm in larvae, ovary and salivary gland were recognized by sera of bovines immunized with rGST-Hl, indicating that the antibodies induced by rGST-Hl immunization recognize native R. microplus GSTs. The bovines were challenged with 20,000 larvae of R. microplus. Protection was calculated by variation in number and weight of fully engorged ticks, egg laying capacity and egg fertility. The bovines vaccinated with rGST-Hl showed a reduction of 53% and 52% in number and weight of engorged ticks, respectively. Egg laying capacity and egg fertility of ticks from vaccinated bovines were respectively 0.6% and 8% lower, as compared to ticks from control animals. The overall efficacy ratio against R. microplus was 57.03%, as compared with the control group.
4

Avaliação da resposta imune humoral em camundongos para a proteína glutationa s-transferase de Rhipicephalus (Boophilus) microplus (GST-Bm), e de haemaphysalis longicornis (GST-HI).

Utiumi, Kiyoko Uemura January 2008 (has links)
O carrapato Rhipicephalus (Boophilus) microplus é um ectoparasito hematófago que infesta os rebanhos bovinos de regiões tropicais e subtropicais, e é um dos principais causadores de prejuízos econômicos à pecuária. O principal método de controle baseia-se no uso de acaricidas. No entanto, devido à crescente preocupação com os problemas criados pela poluição química do meio ambiente, ao alto custo e toxicidade das drogas e ao aparecimento de carrapatos resistentes aos acaricidas, métodos alternativos para o controle do R. microplus devem ser encontrados. Um dos métodos alternativos estudados é o uso de vacinas. As glutationa S-transferases (GST) são enzimas que estão presentes em organismos animais e vegetais e entre suas funções podem-se destacar transporte intracelular, participação em processos digestivos, síntese de prostaglandinas, e detoxificação de substâncias tóxicas e proteção contra estresse oxidativo. Neste estudo foi analisada a resposta imunológica comparativa de camundongos para a GST de R. microplus (GST-Bm) e para a GST de Haemaphysalis longicornis (GST-Hl). Ambas as proteínas foram expressas em Escherichia coli linhagem AD494, e purificadas por cromatografia de afinidade por glutationa utilizando a coluna GSTrap FF. Para verificar a imunogenicidade das proteínas, foram utilizados 25 camundongos Balb/c divididos em 12 grupos. As condições testadas foram as inoculações das proteínas GST-Bm e GST-Hl com os adjuvantes Montanide, saponina ou sem adjuvantes. Camundongos controle foram inoculados com extrato de E. coli ou somente com os adjuvantes. Foi coletado sangue de todos os animais com intervalos de sete dias durante 70 dias. Os soros foram analisados por ELISA para acompanhar a cinética da produção de anticorpos de todos os animais imunizados. Os camundongos inoculados com GST-Hl emulsificada com Montanide mostraram aumento dos níveis de anticorpos a partir do dia 21. O nível máximo de anticorpos foi detectado no dia 42, e diminuiu após o dia 56. Todos os outros animais não apresentaram aumento nos níveis de anticorpos. / Rhipicephalus (Boophilus) microplus tick is a hematophagous ectoparasite that infests cattle in tropical and subtropical regions and is one of the principal causes of economic losses in the cattle farm. The principal method of control is the use of acaricides. However, due to increased worry about environmental chemical pollution, high costs and drugs toxicity and the selection of ticks resistant to acaricides, alternative methods for R. microplus control should be developed. One of these methods is vaccination. Glutathione S-transferases (GSTs) enzymes are present in animal and vegetal organisms and the functions are intracellular transport, participation in digestive process, synthesis of prostaglandins and detoxification of toxic substances and protection against oxidative stress. In this study the immunological response of mice inoculated with R. microplus GST (GST-Bm) and with Haemaphysalis longicornis GST (GST-Hl) was analysed. Both proteins were expressed in Escherichia coli strain AD494 and were purified by affinity chromatography using GSTrap FF columm. To verify the protein immunogenicity, 25 Balb/c mice divided into 12 groups were used. The tested conditions were inoculation of GST-Bm, GST-Hl proteins with Montanide and saponin adjuvants or without adjuvant. Control mice were inoculated with E. coli extract or the adjuvant alone. Blood from all animals were collected with intervals of seven days during seventy days, the sera were analyzed by ELISA to verify the kinetic of antibodies production of all immunized animals. Mice inoculated with GST-Hl emulsified with Montanide showed an increase in the antibodies levels from day 21. The maximum level of antibodies was detected on day 42 and decreased after day 56. The other animals did not show an increase in antibodies levels.
5

Proteção cruzada contra a infestação de Rhipicephalus (Boophilus) microplus em bovinos vacinados com a glutationa-s-transferase recombinante de Haemaphysalis longicornis

Parizi, Luis Fernando January 2010 (has links)
Os carrapatos Rhipicephalus (Boophilus) microplus e Haemaphysalis longicornis são ectoparasitas hematófagos que infestam bovinos. O uso de vacinas anticarrapato tem mostrado ser uma estratégia alternativa promissora para o controle desses parasitos. As glutationa-S-transferases (GSTs) pertencem a uma família de enzimas multifuncionais presentes em organismos animais e vegetais, e, entre suas funções, pode-se destacar o transporte intracelular, a participação em processos digestivos, a síntese de prostaglandinas, a detoxificação de substâncias tóxicas e a proteção contra o estresse oxidativo. Em trabalhos anteriores, verificou-se em camundongos que a GST de H. longicornis (rGST-Hl) é mais imunogênica que a GST de R. microplus (rGST-Bm). O objetivo do presente estudo foi investigar a proteção cruzada conferida pela imunização de bovinos com a rGST-Hl frente a uma infestação de R. microplus. Por Western blot, verificou-se que os bovinos vacinados com a rGST-Hl apresentaram um aumento nos níveis de anticorpos anti-rGST-Hl, os quais foram capazes de reconhecer a GST-Bm nativa de extratos de larva, ovário e glândula salivar. Posteriormente, os bovinos foram infestados com 20.000 larvas de R. microplus. O percentual de proteção conferido foi calculado em função da variação entre os grupos tratados e controle, em relação ao número e peso de carrapatos que terminaram a alimentação, a capacidade de postura e a fertilidade dos ovos. O grupo dos bovinos vacinados com rGST-Hl mostrou uma redução de 53% e 52% no número e no peso de teleóginas, respectivamente. A postura de ovos e a eclodibilidade apresentaram uma redução no grupo vacinado de 0,6% e 8%, respectivamente. A eficácia total contra a infestação de R. microplus foi de 57%, quando comparado ao grupo controle. / The ticks Rhipicephalus (Boophilus) microplus and Haemaphysalis longicornis are hematophagous ectoparasites that infest bovines. Vaccine has been considered one of the most promising methods for the control of these parasites. Glutathione Stransferases (GSTs) enzymes are present in animal and vegetal organisms and are important in intracellular transport, digestive process, synthesis of prostaglandins, detoxification and protection against oxidative stress. In a previous study with mice we showed that H. longicornis GST (rGST-Hl) is more immunogenic than R. microplus GST (rGST-Bm). The objective of the present study was to investigate the crossprotection against R. microplus infestation in bovine vaccinated with rGST-Hl. By Western blot, the immunized bovines showed an increase in antibodies anti-rGST-Hl. The native GST-Bm in larvae, ovary and salivary gland were recognized by sera of bovines immunized with rGST-Hl, indicating that the antibodies induced by rGST-Hl immunization recognize native R. microplus GSTs. The bovines were challenged with 20,000 larvae of R. microplus. Protection was calculated by variation in number and weight of fully engorged ticks, egg laying capacity and egg fertility. The bovines vaccinated with rGST-Hl showed a reduction of 53% and 52% in number and weight of engorged ticks, respectively. Egg laying capacity and egg fertility of ticks from vaccinated bovines were respectively 0.6% and 8% lower, as compared to ticks from control animals. The overall efficacy ratio against R. microplus was 57.03%, as compared with the control group.
6

Avaliação da resposta imune humoral em camundongos para a proteína glutationa s-transferase de Rhipicephalus (Boophilus) microplus (GST-Bm), e de haemaphysalis longicornis (GST-HI).

Utiumi, Kiyoko Uemura January 2008 (has links)
O carrapato Rhipicephalus (Boophilus) microplus é um ectoparasito hematófago que infesta os rebanhos bovinos de regiões tropicais e subtropicais, e é um dos principais causadores de prejuízos econômicos à pecuária. O principal método de controle baseia-se no uso de acaricidas. No entanto, devido à crescente preocupação com os problemas criados pela poluição química do meio ambiente, ao alto custo e toxicidade das drogas e ao aparecimento de carrapatos resistentes aos acaricidas, métodos alternativos para o controle do R. microplus devem ser encontrados. Um dos métodos alternativos estudados é o uso de vacinas. As glutationa S-transferases (GST) são enzimas que estão presentes em organismos animais e vegetais e entre suas funções podem-se destacar transporte intracelular, participação em processos digestivos, síntese de prostaglandinas, e detoxificação de substâncias tóxicas e proteção contra estresse oxidativo. Neste estudo foi analisada a resposta imunológica comparativa de camundongos para a GST de R. microplus (GST-Bm) e para a GST de Haemaphysalis longicornis (GST-Hl). Ambas as proteínas foram expressas em Escherichia coli linhagem AD494, e purificadas por cromatografia de afinidade por glutationa utilizando a coluna GSTrap FF. Para verificar a imunogenicidade das proteínas, foram utilizados 25 camundongos Balb/c divididos em 12 grupos. As condições testadas foram as inoculações das proteínas GST-Bm e GST-Hl com os adjuvantes Montanide, saponina ou sem adjuvantes. Camundongos controle foram inoculados com extrato de E. coli ou somente com os adjuvantes. Foi coletado sangue de todos os animais com intervalos de sete dias durante 70 dias. Os soros foram analisados por ELISA para acompanhar a cinética da produção de anticorpos de todos os animais imunizados. Os camundongos inoculados com GST-Hl emulsificada com Montanide mostraram aumento dos níveis de anticorpos a partir do dia 21. O nível máximo de anticorpos foi detectado no dia 42, e diminuiu após o dia 56. Todos os outros animais não apresentaram aumento nos níveis de anticorpos. / Rhipicephalus (Boophilus) microplus tick is a hematophagous ectoparasite that infests cattle in tropical and subtropical regions and is one of the principal causes of economic losses in the cattle farm. The principal method of control is the use of acaricides. However, due to increased worry about environmental chemical pollution, high costs and drugs toxicity and the selection of ticks resistant to acaricides, alternative methods for R. microplus control should be developed. One of these methods is vaccination. Glutathione S-transferases (GSTs) enzymes are present in animal and vegetal organisms and the functions are intracellular transport, participation in digestive process, synthesis of prostaglandins and detoxification of toxic substances and protection against oxidative stress. In this study the immunological response of mice inoculated with R. microplus GST (GST-Bm) and with Haemaphysalis longicornis GST (GST-Hl) was analysed. Both proteins were expressed in Escherichia coli strain AD494 and were purified by affinity chromatography using GSTrap FF columm. To verify the protein immunogenicity, 25 Balb/c mice divided into 12 groups were used. The tested conditions were inoculation of GST-Bm, GST-Hl proteins with Montanide and saponin adjuvants or without adjuvant. Control mice were inoculated with E. coli extract or the adjuvant alone. Blood from all animals were collected with intervals of seven days during seventy days, the sera were analyzed by ELISA to verify the kinetic of antibodies production of all immunized animals. Mice inoculated with GST-Hl emulsified with Montanide showed an increase in the antibodies levels from day 21. The maximum level of antibodies was detected on day 42 and decreased after day 56. The other animals did not show an increase in antibodies levels.
7

Avaliação da resposta imune humoral em camundongos para a proteína glutationa s-transferase de Rhipicephalus (Boophilus) microplus (GST-Bm), e de haemaphysalis longicornis (GST-HI).

Utiumi, Kiyoko Uemura January 2008 (has links)
O carrapato Rhipicephalus (Boophilus) microplus é um ectoparasito hematófago que infesta os rebanhos bovinos de regiões tropicais e subtropicais, e é um dos principais causadores de prejuízos econômicos à pecuária. O principal método de controle baseia-se no uso de acaricidas. No entanto, devido à crescente preocupação com os problemas criados pela poluição química do meio ambiente, ao alto custo e toxicidade das drogas e ao aparecimento de carrapatos resistentes aos acaricidas, métodos alternativos para o controle do R. microplus devem ser encontrados. Um dos métodos alternativos estudados é o uso de vacinas. As glutationa S-transferases (GST) são enzimas que estão presentes em organismos animais e vegetais e entre suas funções podem-se destacar transporte intracelular, participação em processos digestivos, síntese de prostaglandinas, e detoxificação de substâncias tóxicas e proteção contra estresse oxidativo. Neste estudo foi analisada a resposta imunológica comparativa de camundongos para a GST de R. microplus (GST-Bm) e para a GST de Haemaphysalis longicornis (GST-Hl). Ambas as proteínas foram expressas em Escherichia coli linhagem AD494, e purificadas por cromatografia de afinidade por glutationa utilizando a coluna GSTrap FF. Para verificar a imunogenicidade das proteínas, foram utilizados 25 camundongos Balb/c divididos em 12 grupos. As condições testadas foram as inoculações das proteínas GST-Bm e GST-Hl com os adjuvantes Montanide, saponina ou sem adjuvantes. Camundongos controle foram inoculados com extrato de E. coli ou somente com os adjuvantes. Foi coletado sangue de todos os animais com intervalos de sete dias durante 70 dias. Os soros foram analisados por ELISA para acompanhar a cinética da produção de anticorpos de todos os animais imunizados. Os camundongos inoculados com GST-Hl emulsificada com Montanide mostraram aumento dos níveis de anticorpos a partir do dia 21. O nível máximo de anticorpos foi detectado no dia 42, e diminuiu após o dia 56. Todos os outros animais não apresentaram aumento nos níveis de anticorpos. / Rhipicephalus (Boophilus) microplus tick is a hematophagous ectoparasite that infests cattle in tropical and subtropical regions and is one of the principal causes of economic losses in the cattle farm. The principal method of control is the use of acaricides. However, due to increased worry about environmental chemical pollution, high costs and drugs toxicity and the selection of ticks resistant to acaricides, alternative methods for R. microplus control should be developed. One of these methods is vaccination. Glutathione S-transferases (GSTs) enzymes are present in animal and vegetal organisms and the functions are intracellular transport, participation in digestive process, synthesis of prostaglandins and detoxification of toxic substances and protection against oxidative stress. In this study the immunological response of mice inoculated with R. microplus GST (GST-Bm) and with Haemaphysalis longicornis GST (GST-Hl) was analysed. Both proteins were expressed in Escherichia coli strain AD494 and were purified by affinity chromatography using GSTrap FF columm. To verify the protein immunogenicity, 25 Balb/c mice divided into 12 groups were used. The tested conditions were inoculation of GST-Bm, GST-Hl proteins with Montanide and saponin adjuvants or without adjuvant. Control mice were inoculated with E. coli extract or the adjuvant alone. Blood from all animals were collected with intervals of seven days during seventy days, the sera were analyzed by ELISA to verify the kinetic of antibodies production of all immunized animals. Mice inoculated with GST-Hl emulsified with Montanide showed an increase in the antibodies levels from day 21. The maximum level of antibodies was detected on day 42 and decreased after day 56. The other animals did not show an increase in antibodies levels.
8

Theileria orientalis Ikeda Genotype: Implications for Cattle Health in Virginia

Oakes, Vanessa Jacqueline 30 June 2022 (has links)
Of the four most economically important tickborne diseases of cattle in the world, two have been identified in Virginia, occasionally as co-infections: anaplasmosis and theileriosis. The latter is caused by the emerging infectious agent, the Theileria orientalis complex, in particular the Ikeda and Chitose genotypes. These organisms are carried by the ixodid tick, Haemaphysalis longicornis, recently identified in the United States. Our work has been focused on initially identifying the protozoal organisms, crafting assays to aid in the identification of these organisms in clinically affected animals, and briefly examining the rate of co-occurrence of theileriosis and anaplasmosis. This is important, as Anaplasma marginale - the most common etiologic agent of anaplasmosis in cattle in Virginia - is treatable with a safe, effective, FDA-approved compound, whereas there is no currently approved treatment for theileriosis. Finally, we seek to contextualize theilerosis as a cause of infectious bovine anemia (IBA) and its expected economic impact on the cattle industry in Virginia. / Doctor of Philosophy / Theileriosis is a disease that infects cattle, caused by the blood parasite, Theileria orientalis, specifically two distinct genotypes of T. orientalis, Ikeda and Chitose. Theileriosis is transmitted to cattle by the Asian longhorned tick, Haemaphysalis longicornis, which was recently identified in the United States. Globally, theileriosis is one of four major tickborne diseases of cattle with significant economic importance, so the discovery of this parasite in the state of Virginia is of special importance to the cattle industry in Virginia. My work has revolved around making the initial discovery of T. orientalis Ikeda in the United States, and developing tests for cattle producers and veterinarians to use to help diagnose theileriosis in sick animals. Another tickborne disease of cattle, anaplasmosis, is caused by a bacterium, A. marginale. These two organisms have different biology, are transmitted by different ticks, and are treated differently, but cause identical clinical disease in cattle. In addition to identifying T. orientalis, we have developed a single test that can determine if sick cattle have T. orientalis or A. marginale – this is important, because the antibiotic used to treat A. marginale does not work to treat T. orientalis. In fact, there is no treatment for T. orientalis available in the United States. In addition to developing diagnostic assays, I seek to put into pathobiological, ecological, and economic context the importance of theileriosis on the cattle industry in Virginia.
9

The effects of sympatric and allopatric hab species on calanoid copepod swimming behavior

Nagel, Kathryn 13 January 2014 (has links)
Harmful algal blooms, commonly referred to as red tides, occur yearly with dramatic impacts on marine ecology, coastal economies, and human health. As a consequence, research into the zooplankton grazers that consume HABs is highly important. However, changes in ocean temperature may increase the range of many HABs, exposing historically naive copepods to new species and their associated chemicals. Little research into the impact of allopatric verses sympatric species, particularly on the immediate behavioral impact, has been performed, leaving the indirect fitness effects of HAB exposure and consumption relatively unknown. We measured alterations in the swimming behavior of the calanoid copepod Temora longicornis following exposure to sympatric Alexandrium fundyense and allopatric Karenia brevis treatments. After a 15-16 hours depuration period postA. fundyense exposure, T. longicornis exhibited increased average swimming speed and an elevated net to gross displacement ratio (NGDR). During exposure toK. brevis, copepods exhibited an immediate decrease in swimming speed and NGDR, as well as an increased frequency of jump behavior. However, these effects faded after an one-hour depuration period, and disappeared after a 15-16 hour depuration period. The alterations in swimming behavior demonstrated by the copepods treated A. fundyense may increase encounter rate with predators, while copepods treated with K. brevis remain in bloom conditions for longer periods of time, negatively affecting survivorship. Temora longicornis individuals also may be made more visible to predators due to the increase in jumps seen during treatment with K. brevis. These behavioral changes suggest how HABs escape from zooplankton grazer control by altering copepod swimming behavior, and the pattern of predator-prey evolution that occurs over time.

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