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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.
171

Estrutura da comunidade de helmintos associados ao lagarto Tropidurus torquatus (Squamata: Tropiduridae) em uma área de afloramento rochoso no distrito de Toledos, Juiz de Fora, MG

Pereira, Felipe Bisaggio 24 February 2010 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-12-16T12:33:44Z No. of bitstreams: 1 felipebisaggiopereira.pdf: 1115383 bytes, checksum: c4128dd85e239865ce346d0569b37b98 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-12-19T12:34:46Z (GMT) No. of bitstreams: 1 felipebisaggiopereira.pdf: 1115383 bytes, checksum: c4128dd85e239865ce346d0569b37b98 (MD5) / Made available in DSpace on 2016-12-19T12:34:46Z (GMT). No. of bitstreams: 1 felipebisaggiopereira.pdf: 1115383 bytes, checksum: c4128dd85e239865ce346d0569b37b98 (MD5) Previous issue date: 2010-02-24 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / A comunidade parasitária do lagarto Tropidurus torquatus em uma área de campo rupestre localizada no estado de Minas Gerais, sudeste do Brasil, foi estudada. Dos 110 hospedeiros analisados, 92 (83,6%) estavam infectados. Foram encontradas cinco espécies de helmintos, três de nematóide: Physaloptera lutzi, Parapharyngodon sp. e Oswaldofilaria sp., uma espécie de cestóide e um cistacanto não identificados. Apenas as espécies de nematóides apresentaram dados suficientes para analises ecológicas, sendo P. lutzi a espécie mais prevalente (67,3%) e com maior intensidade parasitária (4,86±4,85). Somente para Oswaldofilaria sp. foram encontradas diferenças significativas na prevalência e intensidade parasitária entre hospedeiros fêmeas e machos, esses últimos apresentando os maiores valores. A intensidade parasitária total e de P. lutzi também diferiram entre os sexos de hospedeiros com machos apresentando os maiores valores. O tamanho corporal do hospedeiro correlacionou-se de forma positiva com a intensidade de infecção de todas as espécies de nematóides. A sazonalidade local não influenciou de forma significativa a estrutura da comunidade componente de parasitos estudada. Aspectos do hospedeiro como dieta, dimorfismo sexual e comportamento (territorialiasmo e forrageamento) representaram importantes fatores na determinação da estrutura dessa comunidade de helmintos. De maneira geral, a comunidade parasitária apresentou baixa riqueza de espécies e um caráter não interativo, características comuns em comunidades parasitárias de répteis como hospedeiros. / The helminth community of the lizard Tropidurus torquatus from a rocky outcrop located in Minas Gerais state, southeast Brazil, was studied. Ninety two of the one hundred ten individuals examined (83,6%) harbored helminths. A total of five helminth species were found, tree nematodes: Physaloptera lutzi, Parapharyngodon sp. and Oswaldofilaria sp., one cestode species and one acanthocaphalan cystacanth not identified. Only nematode species had sufficient data to perform ecological analysis with Physaloptera lutzi showing the highest prevalence (67,3%) and mean intensity (4,86±4,85). Prevalence and intensity of infection between males and females hosts differed only for Oswaldofilaria sp., with males showing the highest values. Total and P. lutzi intensity of infection were different among males and females hosts, with males showing the highest values. The host body size was positively related to intensity of infection for all nematode species. Local seasonality had no influence in the helminth community structure. Host diet, sexual dimorphism and behavior (territorialism, forage strategy) represented important factors in the structuring of this parasite community. In general lines, the helminth community was species poor and non interactive, representing a typical community structure found in herps hosts.
172

Morphological and functional aspects of feeding in the freshwater fish louse Argulus foliaceus (Linnaeus, 1758)

Ambu Ali, Aisha January 2017 (has links)
Argulus foliaceus (Linnaeus, 1758) is a member of the branchiuran family Argulidae and has a worldwide distribution, causing major economic impacts for freshwater aquacultured fish species worldwide. In the UK, it has economic impacts for both aquaculture and sports fishing industries. Previous studies observed haemorrhagic and inflammatory responses after Argulus infection, which has been taken to support the idea that the parasite secretes chemicals during the feeding process to assist with the ingestion of blood and epithelial tissue. The present study suggests that the blood-feeding ectoparasite of fish, A. foliaceus, may use similar mechanisms for evading host immune responses to those used by sea lice and other haematophagous arthropods. No previous studies have directly investigated the nature of the bioactive compounds / proteins, assumed to be released from these ectoparasites, and which are considered to contribute to feeding processes and host-parasite interactions during infection. Thus, the work described in this thesis was undertaken with the objective of identifying, describing and characterising the secretory components that have previously been suggested to be secreted from glandular cells associated with the feeding appendages of Argulus foliaceus. The current study applied transcriptomic and proteomic techniques in conjunction with in situ methods to investigate known immunomodulatory genes that may serve a function in parasite-host interactions. Overall, the findings of this project have generated considerable additional knowledge concerning the biology of Argulus spp. and have provided a list of proteins that may be used by the parasite to facilitate feeding processes by secreting these active molecules into the host and hence modulating their immune defence mechanisms. This information can be used as a baseline for developing freshwater lice control strategies to help prevent the spread of Argulosis in aquaculture by applying vaccination as means of control using the candidate antigens described in this study to specifically target Argulus spp. Knowledge generated by the work described in this thesis can also contribute to the development of drugs for controlling Argulus or functional components of feed that may serve to protect fish against this parasite. Furthermore, data from this thesis enhances the knowledge of the distribution of toxin/venom or venom-like substances in crustaceans and arthropods in general.
173

Levantamento de carrapatos, seus hospedeiros e agentes infecciosos associados, na estação ecológica Samuel, Rondônia, Brasil. / Survey of ticks, their hosts and agents associated infectious, Ecological Station of Samuel, Rondonia, Brazil.

Flávio Aparecido Terassini 18 February 2011 (has links)
Este estudo objetivou estudar os carrapatos e a infecção por patógenos, e sua correlação com os vertebrados desta região entre 10/2007 e 09/2008 foram realizadas mensalmente doze visitas a uma área de floresta ombrófila densa da Amazônica na Estação Ecológica de Samuel. Foram coletados, 60 aves, 36 mamíferos, 14 répteis e 11 anfíbios. Em vida livre foram realizadas 80 coletas de carrapatos em um total de 39.600m em cerca de 2.640min (44h) e coletados 265 carrapatos adultos de quatro espécies, sendo elas: A. scalpturatum (81), A. latepunctatum (84), A. oblongogutattum (18), A. naponense (69) e 597 ninfas de Amblyomma sp. Dos 104 adultos (11,8% do total de carrapatos) foram testados para Anaplasmataceae, obtive-se 27 (25,9%) positivos e mais 36 adultos (total de 140) e 11 carrapatos foram positivos (1) A. scalpturatum, (4) A. latepunctatum, (3) A. naponense. É notável o impacto da hidrelétrica sobre a fauna de pequenos mamíferos. / This study was aimed to analyze the ticks and the pathogenic infections, and their correlation with the vertebrates of such a region from October 2007 to September 2008, 12 surveys were monthly carried out at the Samuel Ecological Station in an Amazonian dense ombrophilous forest. They were collected from 60 birds, 36 mammals, 14 reptiles, and 11 amphibians. Eighty(80) collections of free-living ticks were carried out within an area of about 39.000 meters, during 2.640 minutes (44 hours), and 265 adult ticks or four species were picked up as following: 81 A.scalpturatum, 84 A. latepunctatum, 18 A. oblongogutattum, 69 A. naponense , and 597 Amblyomma sp. nymphs. 104 the adults, which accounted for 11.8% of total of ticks collected, were tested for Anaplasmataceae, and 27 (25.9%) were positive. In the Rickettsia spp. sample, additionally to the above mentioned 104 ticks tested, 36 adult ticks (out of a total of 140) were positive. It is noteworthy the impact caused by the hydropower plant on the small mammal fauna.
174

Adaptations of Trypanosoma brucei to the innate immunity proteins TNF-gas and ApoL-1 / Adaptations de Trypanosoma brucei aux protéines de l'immunité innées TNF-gas et ApoL-1

Vanwalleghem, Gilles 06 March 2012 (has links)
This work allowed the first characterization of the three members of the chloride channel CLC family in T.brucei. The TbCLCs are expressed in the two proliferative stages of the parasite and two of their members appear non-essential. The three TbCLCs act as chloride transporters in X.laevis oocytes and some of their biophysical properties were determined. Furthermore, TbCLC-b appeared to be involved in lysis by the human innate immunity protein apoL-1<p>A novel function of T.brucei adenylate cyclases was discovered in their ability to suppress expression of the innate immunity protein TNF-α. The suppression of the innate response occurs before the first peak of parasitemia and reduces the host ability to control the parasite.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
175

Evaluation of immunological techniques for host fish identification, and cryopreservation of embryos for conserving rare freshwater mussels

Chang, Yunsheng 05 December 2009 (has links)
Glochidia (larvae) of freshwater mussels are obligate parasites which attach to and become encysted in the gills or fins of host fish species. The immune responses of the host fish to the parasite affects the susceptibility of the fish to glochidia of different mussels. The immune response provides an opportunity to identify which fish species are hosts. The number and variety of mussels in rivers and lakes has sharply declined since the last century due to various anthropogenic factors, and some mussels species are facing extinction. It is an urgent task to preserve these vanishing mussels, or extinction will be inevitable. An attempt was made to develop an assay, using the immunological response to glochidia, to screen fish species for appropriate hosts. This would facilitate the production and rearing of juveniles. In order to design these assays, reagents such as anti-immunoglobulins which can react with antibodies from many different fish species have to be developed. This work was carried out to develop such reagents. Host and non-host fish were immunized with killed bacteria (Brucella abortus) to study their humoral immune response to an antigen. All fish were able to respond well, as measured by agglutination and Western Blot assays. Antibodies produced by the Brucella injections were used to stimulate anti-fish immunoglobulins in goats, and the antisera were tested for their ability to recognize immunoglobulins from different host fish species. The specificities of these reactions were compared to the reactivity of Protein A. Goat antisera were able to cross-react with different fish antibodies, but it was found that Protein A was a more suitable reagent. Protein A is seemingly suitable to identify the host-fish species and could be used as a reagent for the serological diagnosis of various fish diseases. / Master of Science
176

Investigação de genes diferencialmente expressos em estágios intra-hospedeiro de Schistosoma mansoni como candidatos vacinais. / Investigation of genes differentialy expressed in intra-host stages of Schistosoma mansoni as vaccine candidates.

Tararam, Cibele Aparecida 20 April 2011 (has links)
A esquistossomose é uma doença importante em saúde pública. Dos genes selecionados como diferencialmente expressos em esquistossômulos a partir do transcriptoma do S. mansoni, 56% foram confirmados por RT-PCR em tempo real. Entre eles, a proteína Ly6.5, está presente no tegumento de esquistossômulos e vermes adultos por âncoras de GPI. Não foi detectada a função de inibir o sistema complemento, mas pode estar envolvido na manutenção do tegumento. O gene SmVal7 revelou transcritos nas glândulas esofágicas de vermes adultos por hibridização in situ, enquanto a localização da proteína não está definida. Anexina está associada ao tegumento de esquistossômulos e vermes adultos, de maneira dependente de cálcio. A supressão do gene por RNAi não resultou em alteração fenotípica significativa em esquistossômulos in vitro. Foi observada atividade parcial de inibição de coagulação e potencial atividade de endocitose de anticorpos ligados à superfície. A imunização com rLy6.5, rSmVal7, rAneI-II ou rAneII-III não levou a redução da carga parasitária após desafio. / Schistosomiasis is an important disease in public health. Genes selected from the S. mansoni transcriptome, 56% of them were confirmed as differentially expressed in schistosomula by real time RT-PCR. Among them, the protein Ly6.5 is present in the tegument of schistosomula and adult worms by GPI anchors. The function of inhibiting the complement system was not detected, but it may be involved in maintenance of the tegument. The gene SmVal7 revealed transcripts in the esophageal glands of adult worms by in situ hybridization, while the localization of the protein is not defined. Annexin is associated with the membranes of the schistosomula and adult worms tegument in a calcium-dependent manner. The suppression of the gene by RNAi did not resulted in a significant phenotypic change in schistosomula in vitro. Parcial inhibition of the coagulation activity and potential function of endocytosis of membrane-bound antibodies were observed. Immunization with the rLy6.5, rSmVal7, rAneI or rAneII-II-III did not show reduction in worm burden recovery after challenge.
177

Monogeneans of the Southern Fiddler Ray, Trygonorrhina Fasciata (Rhinobatidae) in South Australia: an exceptional model to compare parasite life history traits, invasion strategies and host specificity.

Glennon, Vanessa January 2008 (has links)
Trygonorrhina fasciata (Rhinobatidae) specimens naturally infected by three monogenean species were captured and maintained in marine aquaria to promote a continuous parasite load. Monogenean eggs recovered from aquaria provided larvae for descriptions and life history experiments. I describe the adult, larva and post-larval development of a new species of hexabothriid, Branchotenthes octohamatus, from the gills. This is the first monogenean larva described with only eight hooklets. This character may be useful to help resolve problematic relationships within the Hexabothriidae and offers insight into more general hypotheses about relationships within the Monogenea. I also redescribe the adult of Calicotyle australis (Monocotylidae) from the cloaca and describe the larva. The number and arrangement of larval ciliated epidermal cells and sensilla was revealed using silver nitrate. I redescribe Pseudoleptobothrium aptychotremae (Microbothriidae) adults from the skin of T. fasciata, representing a new host and locality record. Larval anatomy and post-larval development are also documented. The presence of six needle-like spicules in the larval haptor is confirmed, supporting an earlier theory that spicules are ancestral vestiges. My studies revealed three different egg hatching, host finding strategies and larval ‘types’. Branchotenthes octohamatus has a ‘sit-and-wait’ strategy, entirely dependent on mechanical disturbance to stimulate eggs to hatch. Larvae are unciliated, cannot swim, lack pigmented eyespots and show no photo-response but may survive for more than two days after hatching at 22ºC. In contrast, eggs of C. australis hatch spontaneously with a strong diurnal rhythm in the first few hours of daylight when exposed to a LD12:12 illumination regime. Larvae are ciliated and can swim, have pigmented eyespots, are photo-positive and can remain active and survive for up to 24 h after hatching at 22ºC. Eggs of P. aptychotremae may have a ‘bet-hedging’ strategy. Some eggs hatch spontaneously and rhythmically in an LD12:12 regime during the last few hours of daylight but their low hatching success rate suggests that other eggs may require a different cue provided by the host. Larvae are ciliated, can swim, lack pigmented eyespots, show no photo-response and remain active for only a few hours at 22ºC. Experiments using the fluorescent dye, 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE) revealed B. octohamatus on gills of T. fasciata within 30 min of exposure to the host. This provides strong evidence that larvae invade the gills directly via the host’s inhalant respiratory current and do not migrate after initial attachment elsewhere. Five rhinobatid species (Aptychotrema vincentiana, T. fasciata, Trygonorrhina sp. A, A. rostrata and Rhinobatos typus), with overlapping distributions spanning west, south and east Australian coastal waters were surveyed for monogeneans at four locations between Fremantle, Western Australia and Stradbroke Island, Queensland. Genetic homogeneity, using the mitochrondrial gene Cytochrome b (cytb) and the nuclear marker, Elongation factor-1 alpha (EF1a), was observed for all Branchotenthes and Calicotyle specimens irrespective of collection locality or rhinobatid species. Genetic homogeneity was observed for Pseudoleptobothrium specimens collected in western and southern Australia. However, local genetic heterogeneity was apparent among Pseudoleptobothrium specimens collected from two sympatric host species in New South Wales. Analyses revealed a highly divergent clade, indicating a morphologically cryptic, ancestral species. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1323070 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008
178

Re-examining Ceratomyxa shasta in the Pacific Northwest

Stinson, Matthew Everett Tsuneo, 1982- 17 February 2012 (has links)
Ceratomyxa shasta infects salmonids in the Pacific Northwest (PNW) of North America, occasionally causing losses in wild and captive populations. Host-specific parasite genotypes (O, I, II, III) were previously characterized molecularly using markers in the ribosomal DNA and phenotypically by type host in the Klamath River, CA/OR. This thesis sough to re-examine the composition of the parasite population elsewhere in the PNW and to further evaluate the host specificity of each genotype. I surveyed salmonids native to the PNW primarily from the Fraser, the Columbia and the Sacramento River basins. I also conducted sentinel studies on the Willamette and Deschutes Rivers that exposed native and non-native salmonids to parasite populations above and below migration barriers. These studies expanded upon the known host range of each genotype: O was specific to rainbow/steelhead (Oncorhynchus mykiss) and coastal cutthroat trout (O. clarkii); I was specific with Chinook salmon (O. tshawytscha); II was non-specific, being detected in six species, but predominating in coho (O. kitsuch), chum (O. keta), and pink (O. gorbuscha) salmon; and III was also non-specific infecting many native and non-native salmonids. Hosts infected with genotype III were considered “adequate” if myxospore development occurred, and included brook char (Salvelinus fontinalis), brown (Salmo trutta), rainbow, cutthroat, and steelhead trout; but Chinook, kokanee/sockeye (O. nerka) and Atlantic salmon (Salmon salar) were less suitable. The distribution, life history, and phylogenetic traits of each salmonid host are factors that potentially explain the host specificity and the spatial and temporal patterns of each genotype. Data collected in this thesis provide evidence that host-specific C. shasta coevolved with Pacific salmonids, adapting unique host-parasite relationships over time. / Graduation date: 2012
179

Hydraulic predictors and seasonal distribution of Manayunkia speciosa density in the Klamath River, CA, with implications for ceratomyxosis, a disease of salmon and trout

Jordan, Michelle S. 09 November 2012 (has links)
The freshwater polychaete Manayunkia speciosa was identified as an obligate host of the salmonid parasite Ceratomyxa shasta in 1997, prompting increased research on the small benthic invertebrate. Ceratomyxa shasta infection in fish can cause mortality, and presents a disease risk for both hatchery and wild salmon and trout. Ceratomyxa shasta is endemic to rivers of the Pacific Northwest, and its effects have been particularly well documented in the Klamath River, Oregon and California. One option for managing C. shasta impacts is by decreasing densities of M. speciosa through habitat manipulation, thus decreasing amplification of the parasite. The Klamath River is regulated by irrigation and hydropower dams, thus manipulating the hydrograph to destabilize habitat is a possibility. Decreasing habitat through flow manipulation requires a thorough understanding of the hydraulic environment of polychaete habitat, and how that environment changes with discharge. This thesis proposes an influence diagram of physical variables driving M. speciosa density, and investigates several of them. Samples were collected for enumerating M. speciosa density from nine sites in the Klamath River over 15 months, and seasonal density changes were examined, as were the relationships between density and hydraulic variables (depth, average velocity, substrate size, Reynolds number, Froude number). Density increased directly with depth and inversely with velocity, and was greater on small (silt, sand) and large (boulder, bedrock) substrate relative to medium substrate (gravel, cobble). Density was highest in the summer (July, August, September), and there was evidence that summer densities were influenced by spring discharges through the mechanism of substrate mobilization. Differences in infection prevalence among seasons and habitats were also investigated; however, very low overall incidence of infection limited any conclusions. Based on these results, it is recommended that habitat modeling for management of M. speciosa populations include a habitat stability component that incorporates s whether peak discharge the previous year surpassed a stability threshold. / Graduation date: 2013
180

Monogeneans of the Southern Fiddler Ray, Trygonorrhina Fasciata (Rhinobatidae) in South Australia: an exceptional model to compare parasite life history traits, invasion strategies and host specificity.

Glennon, Vanessa January 2008 (has links)
Trygonorrhina fasciata (Rhinobatidae) specimens naturally infected by three monogenean species were captured and maintained in marine aquaria to promote a continuous parasite load. Monogenean eggs recovered from aquaria provided larvae for descriptions and life history experiments. I describe the adult, larva and post-larval development of a new species of hexabothriid, Branchotenthes octohamatus, from the gills. This is the first monogenean larva described with only eight hooklets. This character may be useful to help resolve problematic relationships within the Hexabothriidae and offers insight into more general hypotheses about relationships within the Monogenea. I also redescribe the adult of Calicotyle australis (Monocotylidae) from the cloaca and describe the larva. The number and arrangement of larval ciliated epidermal cells and sensilla was revealed using silver nitrate. I redescribe Pseudoleptobothrium aptychotremae (Microbothriidae) adults from the skin of T. fasciata, representing a new host and locality record. Larval anatomy and post-larval development are also documented. The presence of six needle-like spicules in the larval haptor is confirmed, supporting an earlier theory that spicules are ancestral vestiges. My studies revealed three different egg hatching, host finding strategies and larval ‘types’. Branchotenthes octohamatus has a ‘sit-and-wait’ strategy, entirely dependent on mechanical disturbance to stimulate eggs to hatch. Larvae are unciliated, cannot swim, lack pigmented eyespots and show no photo-response but may survive for more than two days after hatching at 22ºC. In contrast, eggs of C. australis hatch spontaneously with a strong diurnal rhythm in the first few hours of daylight when exposed to a LD12:12 illumination regime. Larvae are ciliated and can swim, have pigmented eyespots, are photo-positive and can remain active and survive for up to 24 h after hatching at 22ºC. Eggs of P. aptychotremae may have a ‘bet-hedging’ strategy. Some eggs hatch spontaneously and rhythmically in an LD12:12 regime during the last few hours of daylight but their low hatching success rate suggests that other eggs may require a different cue provided by the host. Larvae are ciliated, can swim, lack pigmented eyespots, show no photo-response and remain active for only a few hours at 22ºC. Experiments using the fluorescent dye, 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE) revealed B. octohamatus on gills of T. fasciata within 30 min of exposure to the host. This provides strong evidence that larvae invade the gills directly via the host’s inhalant respiratory current and do not migrate after initial attachment elsewhere. Five rhinobatid species (Aptychotrema vincentiana, T. fasciata, Trygonorrhina sp. A, A. rostrata and Rhinobatos typus), with overlapping distributions spanning west, south and east Australian coastal waters were surveyed for monogeneans at four locations between Fremantle, Western Australia and Stradbroke Island, Queensland. Genetic homogeneity, using the mitochrondrial gene Cytochrome b (cytb) and the nuclear marker, Elongation factor-1 alpha (EF1a), was observed for all Branchotenthes and Calicotyle specimens irrespective of collection locality or rhinobatid species. Genetic homogeneity was observed for Pseudoleptobothrium specimens collected in western and southern Australia. However, local genetic heterogeneity was apparent among Pseudoleptobothrium specimens collected from two sympatric host species in New South Wales. Analyses revealed a highly divergent clade, indicating a morphologically cryptic, ancestral species. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1323070 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

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