Dissertations / Theses: 'Parasite-host relationship'

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Mubarak, Jamil Salim. "The host-parasite relationship of schistosomes in mice." Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321389.

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McHugh, Timothy Daniel. "Immunological and ultrastructural studies of Strongyloides ratti (Nematoda: Rhabditoidea)." Thesis, University of Portsmouth, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328164.

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López, Gómez Manuel Francisco. "Meloidogyne species in cucurbit crops : characterization and quantification of the host-parasite relationship." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/316398.

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The infection process of Meloidogyne arenaria, M. incognita and M. javanica was compared on zucchini squash, cucumber, melon, pumpkin and watermelon in a growth chamber. All cucurbits were susceptible to the three isolates although M. javanica showed higher invasion rates, faster development and egg production than M. arenaria. Differences among cucurbits were primarily due to root invasion rates and formation of egg masses. Cucumber and melon were better hosts for nematode invasion and reproduction than zucchini followed by watermelon. The suitability of five zucchini, three cucumber, eight watermelon and seven cucurbit rootstocks genotypes to M. incognita (MiPM26) and M. javanica (Mj05) was determined. The number of egg masses did not differ among the genotypes of zucchini or cucumber, but the reproduction factor did slightly. A marked differenced was observed between the nematode isolates; M. incognita MiPM26 showed lower reproduction traits than M. javanica Mj05, and, in zucchini, only 22% of the females of M. incognita produced egg masses compared to 95% of the M. javanica females. In cucumber, 86% of the M. incognita and 99% of the M. javanica females produced egg masses. Also, populations of the three Meloidogyne species were tested on zucchini and cucumber. A greater parasitic variation was observed on zucchini than cucumber. Zucchini responded as a poor host for M. incognita MiPM26, MiAL09 and MiAL48, but as a good host for MiAL10 and MiAL15. Cucumber was a good host for all the tested populations. The watermelon cultivars did not differ in host status within each nematode isolate, supporting lower reproduction than the cucurbit rootstocks. The top development of field-grown non-grafted watermelon plants was significantly delayed in plots where the nematodes were detected at planting. However, no differences were observed in plots with grafted plants. In plots with nematodes, non-grafted and Titan-grafted plants had similar yield, which was higher than that of RS841-grafted plants. The Titan-Sugar Baby combination was tolerant to M. javanica. The relationship between the Pi and final (Pf) population densities of M. javanica in response to increasing initial inoculum levels and the effect on yield in zucchini cv. Amalthee were determined using a geometric series of 12 Pi from 0 to 51,200 eggs/100 cm3 of soil. The maximum multiplication rate of the nematode was 425, and the equilibrium density was 701,951 eggs/100 cm3 soil. The relative yield, represented as dry top weight, fitted the Seinhorst damage function model and the minimum relative yield (m) was 0.82 and the tolerance limit (T) was 402 J2/100 cm3 soil. Regression analyses indicated a negative relationship between the Pi and the leaf chlorophyll content, fitting the Seinhorst damage-function model. Zucchini cv. Dyamant was planted in a plastic greenhouse with a range of M. javanica Pi from 0 to 861 J2/100 cm3 soil. The maximum multiplication rate of M. javanica under field conditions was 3,093, and the equilibrium density was 1,485 J2/100 cm3 soil. The relationship between Pi and relative yield, represented as fruit weight, fitted the Seinhorst damage function model and m was 0.48, and T was 0.02 J2/100 cm3 soil. The relationship between the Pi and Pf of M. javanica in response to increasing initial inoculum levels and the effect on yield in watermelon cv. Sugar Baby were determined. The maximum reproduction rate of the nematode was 14, and the equilibrium density 49,400 eggs/100 cm3 of soil. Yield data represented as fresh top weight fitted the Seinhorst damage function, and m was 0.65 and T was 74 eggs/100 cm3 of soil. In the field experiments (2011 and 2012), the maximum reproduction rate was 73 and 70, and the equilibrium density 32 and 35 J2/100 cm3 soil. Yield data, represented as fruit weight, fitted the Seinhorst damage function in 2011 and the m and T values were 0.63 and 20 J2/100 cm3 of soil, respectively
Se estudió el proceso infectivo y el desarrollo post-infeccional de Meloidogyne arenaria, M. incognita y M. javanica en calabacín, pepino, melón, calabaza y sandía. Como resultado indicar que todas las cucurbitáceas ensayadas fueron susceptibles a los tres aislados, aunque M. javanica mostró mayor tasa de invasión, desarrollo más rápido y mayor producción de huevos que M. arenaria. El pepino y el melón presentaron mayor tasa de invasión y reproducción que el calabacín y la calabaza, seguidos de la sandía. La susceptibilidad de cinco genotipos de calabacín, tres de pepino, ocho de sandia y siete de patrones de cucurbitáceas a dos poblaciones de Meloidogyne: M. incognita (MiPM26) y M. javanica (Mj05). El calabacín proporciona condiciones inadecuadas para el desarrollo de M. incognita, ya que sólo el 22% de las hembras produjo masas de huevos en comparación con el 95% de las hembras de M. javanica. En pepino, el 86% de las hembras de M. incognita y el 99% de M. javanica produjeron masas de huevos. Además, poblaciones de tres especies de Meloidogyne se estudiaron en calabacín y pepino. En calabacín se observo una mayor variación parasitaria que en pepino, comportándose como huésped pobre para las poblaciones de M. incognita MiPM26, MiAL09 y MiAL48, mientras que respondía como buen huésped para las poblaciones MiAL10 y MiAL15. M. incognita mostró mayor reproducción que M. javanica en los cultivares de sandía y patrones de cucurbitáceas. Los cultivares de sandía no difirieron en la idoneidad del huésped para cada aislado del nematodo y soportaron menos reproducción que los patrones de cucurbitáceas. Las sandías no injertadas mostraron un retrasó significativo en su desarrollo aéreo en las parcelas donde se detecto el nematodo al inicio del cultivo. Sin embargo, no se observo tal efecto en las sandías injertadas. En las parcelas donde se detectó en el nematodo al inicio del cultivo, las sandías no injertadas y las injertadas sobre Titan mostraron un producción similar, mayor que la de las plantas injertadas sobre RS841 en parcelas con presencia del nematodo al inicio del cultivo. El injerto de la sandía sobre Titan proporciono tolerancia frente a M. javanica. La relación entre Pi y Pf de M. javanica en respuesta a niveles crecientes de Pi, y el efecto sobre la producción de calabacín cv. Amalthee utilizando una serie geométrica de 12 Pi crecientes comprendidas entre 0 y 51.200 huevos/100 cm3 de suelo. La tasa máxima de multiplicación del nematodo fue 425, y la densidad de equilibrio fue 701.951 huevos/100 cm3 suelo. La producción se ajustó al modelo de daño de Seinhorst, dando como resultado una producción mínima (m) de 0,82 y un límite de tolerancia (T) de 402 J2/100 cm3 de suelo. El calabacín cv. Dyamant se plantó en un invernadero infestado con M. javanica con Pi que oscilaba entre 0 y 861 J2/100 cm3 de suelo. La tasa máxima de multiplicación fue 3093, y la densidad de equilibrio fue de 1485 J2/100 cm3 de suelo. La relación entre la Pi y la producción se ajustó al modelo de daño de Seinhorst; el valor de m fue 0,48, y el de T fue 0,02 J2/100 cm3 de suelo. La relación entre la Pi y la Pf de M. javanica en respuesta inóculos iniciales crecientes y el efecto en producción de sandía cv. Sugar Baby se determinó en experimentos en maceta y en campo. En maceta, la tasa máxima de reproducción del nematodo fue de 14, y la densidad de equilibrio fue de 49.400 huevos/100 cm3 de suelo. Los datos de producción, representados como peso fresco de la biomasa aérea, se ajustaron al modelo de daño de Seinhorst, siendo m igual a 0,65 y T igual a 74 huevos/100 cm3 de suelo. En los experimentos de campo (años 2011 y 2012), la tasa máxima de reproducción fue de 73 y 70, y la densidad de equilibrio de 32 y 35 J2/100 cm3 de suelo. Los datos de producción, expresada en peso de los frutos/ parcela elemental, se ajustó a la función de daño de Seinhorst en 2011, siendo los valores m y T 0,63 y 20 J2/100 cm3 de suelo, respectivamente.

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Farmer, Kristy Lynn Roberts Sharon R. "Study of a novel host-parasite relationship Mycoplasma gallisepticum in house finches (Carpodacus Mexicanus) /." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Dissertations/FARMER_KRISTY_6.pdf.

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Garside, Paul. "The host-parasite relationship in the Ancylostoma ceylanicum/hamster model of human hookworm infection." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238214.

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Norozian, Seyed Mohammed Bagher. "Aspect of the host-parasite relationship of hookworms 'N. americanus and A. ceylanicum' in hamsters." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336176.

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ShaÌ„hid, MuhÌ£ammad. "Studies on the host-parasite relationship between Pasteuria penetrans and root-knot nematodes (Meloidogyne spp.)." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287653.

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Gu, Henry Yuekun. "The role of microRNAs in the host-parasite relationship in the veterinary nematode Haemonchus contortus." Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7786/.

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Haemonchus contortus is one of the most pathogenic nematodes of small ruminants, particularly sheep, and has a major impact on welfare as well as causing significant economic losses to farmers worldwide. In this project, the possible interaction of parasite microRNAs with the host’s immune response was investigated with a view to determining whether microRNAs may enhance parasite survival. microRNAs are 22 nucleotides long, non-coding RNA molecules that bind to target sites with complementary sequences on mRNAs, usually in the 3' UTR. This interaction causes degradation of the mRNA or suppression of protein synthesis (Bartel, 2009; Selbach et al., 2008). A previous study identified 192 microRNAs in H. contortus, a large proportion of which were unique to parasitic nematodes (Winter et al., 2012). One particular microRNA, Hco-miR-5352 is of particular interest and is the major focus of this study. This microRNA is one of a cluster of four microRNAs (the miR-5352 cluster) which is conserved predominantly in nematodes that reside within the gastro-intestinal tract. Microarray and qRT-PCR data show that the miR-5352 cluster was most highly expressed in parasitic stages of the H. contortus life cycle. Some members of the cluster were detected in the excretory-secretory products of H. contortus as well as in abomasal and lymph node tissues taken from sheep infected with H. contortus. Transmission electron microscopy of the excretory-secretory products showed the presence of small vesicle-like structures. The data presented here showed that H. contortus releases a range of microRNAs in the excretory-secretory products, some of which were present within extracellular vesicles. Bioinformatic target prediction methods identified CD69 as a likely target of Hco-miR-5352 and this interaction was demonstrated experimentally using a dual luciferase assay. However the interaction was not confirmed using an inducible CD69 system in Jurkat T cells. The impact of Hco-miR-5352 on global gene expression of an intestinal epithelial cell line identified several interesting targets with important roles in the host immune response against H. contortus, the regulation of which may be important in parasite survival within the host.

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Belosevic, Miodrag. "Biological and immunological aspects of the host-parasite relationship in infections of mice with Giardia muris." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72072.

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Biological and immunological aspects of the host-parasite relationship were examined in mice which are susceptible (A/J) and resistant (B10.A) to Giardia muris. B10.A exhibited a shorter latent period, lower cyst output during the acute phase of the infection and shorter period of cyst release compared to A/J. Characteristics of the infection transmitted from mouse-to-mouse and those induced by oral inoculation with cysts or trophozoites were similar. The infection was longer in male A/J and B10.A mice compared to females. Susceptibility and resistance during both the acute and elimination phases of the infection were under non-H-2-linked multigenic control. A/J and B10.A differed in non-specific serum IgG and IgA, but not in the specific IgG and IgA to G. muris. Specific antibodies participated in complement-mediated killing of trophozoites. Spleen, mesenteric lymph node and peritoneal cells from A/J and B10.A mice had a similar ability to kill trophozoites. The capacity of B10.A to mount inflammatory responses was greater than that of A/J. A/J were more immunosuppressed than B10.A during the infection, particularly at mucosal sites. Macrophage-like suppressor cells were shown to be the mediators of this suppression.

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Brailsford, T. J. "The effects of malnutrition upon the host : Parasite relationship of Heligmosomoides polygyrus (nematoda, trichostrongylidae) in mice." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384484.

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Johnson, Lindsay. "Experimental study of the host-parasite relationship between the guppy (Poecilia reticulata), and Gyrodactylus turnbulli (Monogenea)." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46369.

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Winser, Helena. "Host - parasite interactions: : the relationship between encystment load of the freshwater pearl mussel (Margaritifera margaritifera) and genetic diversity of its host (Salmo trutta)." Thesis, Karlstads universitet, Institutionen för miljö- och livsvetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-38777.

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The freshwater pearl mussel (FPM, Margaritifera margaritifera) is an endangered bivalve mollusc with an obligatory larval parasitic phase on brown trout (Salmo trutta). The FPM has declined throughout its entire range due to causes such as habitat degradation, eutrophication, acidification, changed hydrology and lack of host fish. This study aimed to investigate if heterozygosity, allelic richness, number of alleles, inbreeding and differentiation of brown trout (Salmo trutta) are related to the encystment load of glochidia larvae of the FPM. The results showed that the observed heterozygosity was negatively related to encystment load. This may be a result of the fact that high heterozygosity is generally associated with a strong immune system that wards off parasities. High heterozygosity may also be an advantage for the host, because it results in a larger potential for selection against the parasite in the host-parasite arms race. There was also a positive relationship between the inbreeding coefficient and glochidia encystment. This makes sense since high inbreeding is negatively related to heterozygosity. High inbreeding of trout should thus reduce the ability of inbred trout populations to ward off parasites. The results may have implications for conservation management. Introductions of foreign trout strains that alter the genetic interactions between the host fish and the parasitic mussel should be managed. Small and fragmented trout mussel populations, with typically high inbreeding coefficients, may have a relatively high probability to reproduce and survive and it may therefore be worthwhile to protect these trout populations. However, inbred trout populations should be managed with care, since inbreeding increases the risk of extinction of the trout. If a trout population is extinct, their sympatric mussel population may thus face extinction as well.

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Alcântara, Daniel Máximo Corrêa de. "Revisão taxonômica e filogenia do gênero Noctiliostrebla Wenzel, 1966 (Diptera, Streblidae)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-27082014-094438/.

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Noctiliostrebla Wenzel, 1966 pertence a Streblidae, uma família de moscas parasitas exclusivas de morcegos, e compreende atualmente quatro espécies divididas em dois grupos, grupo A: Noctiliostrebla dúbia (Rudow, 1871) e N. traubi Wenzel, 1966; e grupo B: N. aitkeni Wenzel, 1966 e N. maai Wenzel, 1966. O gênero está incluído dentro da subfamília Trichobiinae, junto com Paradyschiria Speiser, 1900, sugerido como seu grupo-irmão hipotético. Com uma classificação sistemática complicada e poucos estudos taxonômicos, Noctiliostrebla caracteriza-se como um grupo muito homogêneo e de difícil distinção entre suas espécies. Restrito ao continente americano, exibe um alto grau de especificidade em relação às duas únicas espécies de morcegos do gênero Noctilio Linnaeus, 1766, N. albiventris Desmarest, 1818 e N. leporinus (Linnaeus, 1758). Não existem trabalhos filogenéticos para Noctiliostrebla, sendo que, os únicos estudos envolvendo Streblidae foram feitos para propor uma hipótese de relacionamentos entre as famílias de Hippoboscoidea. O projeto tem como objetivos realizar a revisão taxonômica do gênero Noctilostrebla e reconstruir uma hipótese de relacionamento entre as espécies do gênero, utilizando caracteres morfológicos e um conjunto de dados moleculares composto por três genes mitocondriais (12S, COI e cytB) e um gene nuclear (CAD). Dois métodos de análise foram empregados: análise de parcimônia, com pesagem igual dos caracteres, e análise de máxima verossimillhança. As análises foram realizadas com dados morfológicos e moleculares separados, enquanto os dados moleculares foram analisados com genes concatenados e separados em mitocondriais e nucleares. Como resultados, as quatro espécies já descritas foram consideradas válidas, sendo aqui redescritas, e outras seis novas espécies foram descritas. Do total de onze espécies, cinco são parasitas restritos de N. albiventris e seis de N. leporinus. As estruturas abdominais forneceram os únicos caracteres diagnósticos encontrados para separação entre as espécies. Tanto a análise morfológica como a molecular recuperaram Noctiliostrebla como monofilético e corroboraram a divisão do gênero em dois clados morfologicamente distintos. As análises com genes mitocondriais e nucleares foram incongruentes com relação a alguns clados, o que pode ser um indicativo de histórias filogenéticas diferentes. Os resultados obtidos para Noctiliostrebla apresentaram semelhanças com as hipóteses consideradas para os hospedeiros
Noctiliostrebla Wenzel 1966 belongs to Streblida, a family of batflies, and currently comprises four species divided into two groups, group A: Noctiliostrebla dubia (Rudow, 1871) and N. traubi Wenzel, 1966; Group B: N. aitkeni. Wenzel, 1966 and N. maai Wenzel, 1966. The genus is included within the Trichobiinae subfamily, along with Paradyschiria Speiser, 1900, suggested as your hypothetical sister group. With a complicated systematic classification and a few taxonomic studies, Noctiliostrebla is characterized as a very homogeneous group and difficult to distinguish between their species. Restricted to the American continent, exhibits a high degree of specificity with the only two bats species of the genus Noctilio Linnaeus, 1766, N. albiventris Desmarest, 1818 and N. leporinus (Linnaeus, 1758). There are no phylogenetic works with Noctiliostrebla and the only studies involving Streblidae were made to propose a relationship hypothesis among Hippoboscoidea families. The project aims to conduct a taxonomic revision of the Noctilostrebla genus and to rebuild a relationship hypothesis among Noctilostrebla species using morphological and molecular data set, with three mitochondrial genes (12S, COI and cytB) and one nuclear gene (CAD). Two analysis methods were used: parsimony with equal weighting of characters and lielihood. The analyses were performed using morphological and molecular data separate, while the molecular data were analyzed with concatenated genes and separated into mitochondrial and nuclear genes. As a result, the four described species were considered valid being here redescribed, and six new species have been described. Of all eleven species, five are restricted parasites of N. albiventris and six are restricted parasites of N. leporinus. The abdominal structures provided the only diagnostic characters found for separation of the species. Both morphological and molecular analysis recovered a monophyletic Noctiliostrebla and supported the division of the genus into two distinct clades. The analyses of mitochondrial and nuclear genes showed inconsistent clades, which may be indicative of different phylogenetic histories. The results obtained for Noctiliostrebla showed similarities with the assumptions for the hosts

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Bienek, Diane Rose. "The biological and immunological aspect of the host-parasite relationship of goldfish, Carassius auratus, infected with Trypanosoma danilewskyi." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60274.pdf.

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Sims, Thomas Anthony. "A light and electron microscope investigation of the host-parasite relationship in the brains of mice with congenital toxoplasmosis." Thesis, De Montfort University, 1992. http://hdl.handle.net/2086/10749.

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Impregnation of the wall of intact tissue cysts in the brains of mice with congenital toxoplasmosis, with reduced silver salts and protargol silver suggested that it was composed, at least in part, of components derived from the neuronal cytoskeleton. Electron microscopy extended these observations and revealed that intact tissue cysts were separated from the extra-cellular compartment by a layer of neurofibrillae enclosed within the host cell membranes. Immunohistochemical staining confirmed that this layer contained neurofilament protein. Interior to this layer was a much convoluted parasitophorous vacuole membrane; exterior was the host cell membrane. In most cases, synaptic plates were noted on the outer plasma membrane. In no instance were tissue cysts observed either within neuroglial cells or in the absence of a host cell. Electron immunocytochemistry, using a rabbit polyclonal antiToxoplasma IgG as the primary layer in immunogold staining, revealed that Toxoplasma antigenwas widely distributed within the matrix of the cyst, being most concentrated in the proximity of the inner surface of the parasitophorous vacuole membrane. Relatively little Toxoplasma antigen was detected directly associated with cystozoites. Small amounts of antigen were detected directly associated with cystozoites, within host cell components exterior to the parasitophorous vacuole membrane and in the host neuropil, immediately adjacent to the tissue cyst. The inter-relationship between inflammatory lesions associated with small vessels, in close proximity to intact tissue cysts, suggest that there may be 'migration' of these cells, in an ordered sequence, towards the Toxoplasma antigen secreted from the tissue cysts.

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Sörén, Kaisa. "Experimental Schistosoma bovis infections in goats : studies on the host-parasite relationship with special reference to immunoregulatory effects and immunopathology /." Uppsala : Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200917.pdf.

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Denholm, Scott J. "Mathematical models for investigating the long-term impact of Gyrodactylus salaris infections on Atlantic salmon populations." Thesis, University of Stirling, 2013. http://hdl.handle.net/1893/17021.

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Gyrodactylus salaris Malmberg, 1957, is a notifiable freshwater ecto-parasite that infects both wild and farmed populations of Atlantic salmon (Salmo salar, L.). It has caused catastrophic damage to wild salmon stocks in Norway since its accidental introduction in 1975, reducing salmon density in some rivers by 98% over a period of five years. It is estimated that G. salaris has cost the Norwegian salmon industry more than 500 million EUR. Currently the UK has G. salaris free status under EU law, however, it is believed that if G. salaris emerged in the UK the impact would be similar to that witnessed in Norway. The aim of this thesis is to develop mathematical models that describe the salmon-G. salaris system in order to gain a greater understanding of the possible long-term impact the parasite may have on wild populations of Atlantic salmon in G. salaris-free territories such as the UK. Mathematical models, including deterministic, Leslie matrix and individual based models, were used to investigate the impact of G. salaris on Atlantic salmon at the individual and population level. It is known that the Atlantic strain of Atlantic salmon, examples of which occur naturally in Norway and the UK, does not have any resistance to G. salaris infections and the parasite population is able to quickly grow to epidemic levels. In contrast, the Baltic strain of Atlantic salmon, examples of which occur naturally in Sweden and Russia, exhibits some form of resistance and the parasite is unable to persist. Thus, baseline models were extended to include immunity to infection, a trade-off on salmon reproductive rate, and finally, to consider interactions between populations of G. salaris and multiple strains of salmon exhibiting varying levels of immunity from fully susceptible to resistant. The models proposed predict that in the absence of host resistance or an immune response infections by G. salaris will result in an epidemic followed by the extinction of the salmon host population. Models also predict that if salmon are able to increase their resistance to G. salaris infections through mutations, salmon population recovery after the epidemic is indeed possible within 10-15 years post introduction with low level parasite coexistence. Finally, models also highlight areas where additional information is needed in order to improve predictions and enable the estimation of important parameter values. Model predictions will ultimately be used to assist in future contingency planning against G. salaris outbreaks in the UK and possibly as a basis for future models describing other fish/ecto-parasite systems.

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Silva, Primalie De. "Studies on some of the important features in the biological relationship between the bacterial parasite Pasteuria penetrans and its host Meloidogyne SPP." Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306202.

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Ferrari, Nicola. "Macroparasite transmission and dynamics in Apodemus flavicollis." Thesis, University of Stirling, 2005. http://hdl.handle.net/1893/105.

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This thesis examines the parasite dynamics and the mechanisms affecting parasite load and transmission focalising on the role played by host and habitat heterogeneities. This study is based on the gastrointestinal nematode Heligmosomoides polygyrus and the small mammal yellow necked mouse and uses data gathered from experimental field manipulations of parasites intensities and data gathered from trapping monitoring. Initially the parasite community of yellow-necked mouse (Apodemus flavicollis) was explored in North-Eastern Italian Alps with the aim to describe the major patterns and identify the factors affecting parasite community structure. Despite the observed spatial variability it has been found that differences within the host population such age and secondly sex and breeding conditions, were the major factors acting on parasite occurrence and intensity. Habitat differences had a less apparent effect on parasite community structure. The consequences of H. polygyrus infection on other parasite species infections have been analysed, in specific the infestation of the tick Ixodes ricinus in populations of A. flavicollis. H. polygyrus load and tick infestation were monitored as well as were carried out field manipulations of H. polygyrus intensity and were monitored changes in tick infestation. It has been found that H. polygyrus load was negatively related to I. ricinus infestations. Host factors mediated the H. polygyrus-I. ricinus interaction such that young and non-breeding mice exhibited higher I. ricinus to H. polygyrus intensity respect breeding adults. The role of host sex on parasite abundance was then investigated carrying out a field experiment where the H. polygyrus intensity were manipulated in relation to mice gender. In specific, H. polygyrus was removed alternately from either sexes and the parasite load was analysed in the untreated sex. It was found that males mice were responsible to drive parasite transmission in the host population and this was observed in absence of sex-bias in parasite infection, suggesting that this pattern was not a mere consequence of quantitative differences in parasite loads between sexes. To disentangle the possible mechanism causing this sex bias in parasite transmission mathematical simulations based on parameters obtained for the field experiment were used. Two non mutually exclusive hypotheses causing sex bias in parasite transmission were tested: a- males immune response is less efficient and this causes the development of more successful parasite infective stages or b-males behaviours allow them to be more efficient is spreading in more exposed areas parasite infective stages. Multi-host models were developed and simulations were compared with field results. While it was not disentangled the most dominant mechanism causing sex bias in parasite transmission this study underlined the importance of host sexes in affecting parasite dynamics and host-parasite interaction. In conclusion this thesis highlighted the importance of considering host and environmental differences when investigating host parasite interactions. This finding could be extremely important when planning measured of disease control or to avoid disease outbreak. Controlling target group of individuals host could avoid economical losses and a more effective measure of intervention.

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Fernandez, Ruth Miriam Alva. "Associa??o entre Amblyomma cajennense e Boophilus microplus em Infesta??o Simult?nea de Bovinos Holand?s - Zebu." Universidade Federal Rural do Rio de Janeiro, 1990. https://tede.ufrrj.br/jspui/handle/tede/737.

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Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Steers were used as experimental host for Amblyomma cajennense and Boophilus microplus during simultaneous infections on ears and quarters. Thus, the study shows especifically teleoginas and quenoginas weight, egg production, eclodibility and oviposition period. The ticks were held in laboratoryconditions at 27?C and 70% UR. It was observed that teleoginas collected from the ears were lighter than those collected from hind quarters. Egg production index (EPI) and nutrient efficiency index (NEI) for A. cajennense was 45,74% and 60,36%, respectively, and for B. microplus was 42,58% and 59,51%, respectively. The eclodibility index from simultaneous infection was lower than individual infections. The correlation between teleogina weight and egg production for both ticks specie showed that the number of eggs was influenced by teleogina weight. The interaction between A. cajennense and B. microplus is reported for simultaneous infection on bovine.
Utilizando bovinos como hospedeiros, avaliou-se o comportamento de Amblyomma cajennense e Boophilus microplus em infesta??es simult?neas na orelha e anca, essa em ?reas de aproximadamente 60 cm2. O estudo focalizou prioritariamente o peso das tele?ginas, das quen?ginas, a produ??o de ovos, o tempo de ovipostura e a eclodibilidade. Os carrapatos foram criados em laborat?rio em estufa do tipo B.O.D. com temperatura controlada de 27? C e unidade relativa de 70 ? 10%, e mantidos isoladamente ap?s desprendimento do hospedeiro nas mesmas condi??es laboratoriais. As tele?ginas que ingurgitaram na orelha pesaram menos que as alimentadas nas ancas em ambas as esp?cies; o ?ndice de produ??o de ovos (IPO) e o ?ndice de efici?ncia nutricional (IEN) para A. cajennense e B. microplus foram 45,74 e 42,58%, e 60,36 e 59,5%, respectivamente. As taxas de eclodibilidade foram menores que as j? assinaladas para infesta??es individuais nas duas esp?cies. A correla??o entre o peso da tele?gina das duas esp?cies e a produ??o de ovos foi significativa, comprovando ser o n?mero de ovos ovipostos fun??o do peso da f?mea antes do ?nicio da postura. Concluindo-se haver intera??o entre A. cajennense e B. microplus em infesta??o simult?nea em bovinos.

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Yoshida, Kentaro. "A molecular population genetic study of nuclear loci involved in the host-parasite relationship of the wild rice Oryza rufipogon and the blast fungus Pyricularia oryzae." Kyoto University, 2006. http://hdl.handle.net/2433/136494.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第12560号
農博第1579号
新制||農||931(附属図書館)
学位論文||H18||N4176(農学部図書室)
UT51-2006-P20
京都大学大学院農学研究科応用生物科学専攻
(主査)教授遠藤隆, 教授大西近江, 教授谷坂隆俊
学位規則第4条第1項該当

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Täubert, Jens-Eike [Verfasser], Jürgen P. [Akademischer Betreuer] Geist, and Ralph P. [Akademischer Betreuer] Kühn. "Host-parasite interactions in aquatic ecosystems - The relationship between fishes and endangered freshwater mussels / Jens-Eike Täubert. Gutachter: Ralph P. Kühn ; Jürgen P. Geist. Betreuer: Jürgen P. Geist." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1056035641/34.

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Christen, Susan Ehlert. "Amplificação do gene da Chaperonina HSP10 do Trypanosoma evansi." Universidade do Estado de Santa Catarina, 2010. http://tede.udesc.br/handle/handle/846.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
The trypanosomiasis is enzootic caused by several species of the genus Trypanosoma. It is a hemoflagellate widely distributed and of great veterinary importance, because infects a wide variety of mammals. Trypanosoma evansi is the causative agent of disease popularly known as surra , which has great economic importance in Africa, Asia and South America. These protozoa possess digenetic life cycles. When the parasites move from vector to host they suffer a heat shock. The HSPs are found in several pathogens, where the heat shock is a natural event of their biology. The heat shock response is a homeostatic mechanism that protects cells from the deleterious effects of environmental stress. The HSPs have a key role in intracellular work such as DNA replication, cell division, transcription, translation, functions in membrane transport proteins as well as providing assistance to correct protein folding nascent and unfolded by stress accumulation. This work aimed to amplify the HSP10 gene, to be able, afterwards, to observe its expression in trypanosomatids. Rats Wistar were infected with T. evansi, the parasites were purified, the DNA and RNA extraction was made, beyond the reverse transcriptase, PCR, transformation into E. coli DH5α and sequencing of clones. The bands that corresponded to the size of HSP10 gene were selected for clone. The constructions of the inserts selected were subjected to sequencing to verify the correct construction of the clones. The sequencing analysis showed that the sequence obtained has a homology of 40% corresponding to HSP10 hypothetical T. brucei. This is one of the first papers that attempted to identify a gene family of HSPs in T. evansi, that should be used as a chemotherapeutic target
A tripanossomíase é uma enzootia ocasionada por diversas espécies do gênero Trypanosoma. Este é um hemoflagelado amplamente distribuído e de grande importância veterinária, pois infecta uma grande variedade de mamíferos. O Trypanosoma evansi é o agente causador da doença denominada popularmente como surra, que possui grande importância econômica na África, Ásia e América do Sul. Estes protozoários possuem ciclos de vida digenéticos. Quando os parasitos passam do vetor para o hospedeiro estes acabam sofrendo um choque térmico. As HSPs são encontradas em uma variedade de patógenos, onde o choque térmico é um evento natural de sua biologia. A resposta de choque térmico é um mecanismo homeostático que protege as células dos efeitos deletérios do estresse ambiental. As HSPs possuem um papel fundamental no trabalho intracelular como replicação de DNA, divisão celular, transcrição, tradução, funções nas membranas, transporte de proteínas, além de darem assistência correta ao enovelamento de proteínas nascentes e desenoveladas pelo acúmulo de estresse. Este trabalho teve como intuito amplificar o gene da HSP10, para que seja possível futuramente observar sua expressão nos tripanosomatídeos. Ratos Wistar foram infectados com T. evansi, os parasitos foram purificados, efetuou-se a extração de DNA e RNA, além da transcrição reversa, PCR, transformação em E. coli DH5α e o seqüenciamento dos clones. As bandas que corresponderam ao tamanho do gene HSP10 foram selecionadas para clonagem. As construções dos insertos selecionados foram submetidos ao sequenciamento a fim de verificar a construção correta dos clones. A análise do seqüenciamento demonstrou que a sequência obtida possui uma homologia de 40% correspondente a HSP10 hipotética de T. brucei. Este é um dos primeiros trabalhos que buscam identificar um gene da família das HSPs em T. evansi, que poderá ser usado como alvo quimioterápico

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Naldoni, Juliana 1986. "Myxozoa parasitos de Pseudoplatystoma corruscans (pintado), Salminus franciscanus (dourado) e Brycon orthotaenia (matrinxã) oriundos da bacia do rio São Francisco, MG." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317462.

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Orientador: Edson Aparecido Adriano
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Mixosporídeos são cosmopolitas e infectam peixes em diversas regiões do mundo. Atualmente são conhecidas cerca de 2.400 espécies, das quais a grande maioria é parasito de peixes, tanto de ambiente natural como de sistemas de criação, sendo algumas espécies responsáveis por altas taxas de mortalidade em várias partes do mundo. Este trabalho teve como objetivo o estudo da diversidade de mixosporídeos parasitos de Pseudoplatystoma corruscans (pintado), Salminus franciscanus (dourado) e Brycon orthotaenia (matrinxã) da bacia do rio são Francisco, município de Pirapora, MG, Brasil. Foram realizados estudos morfológicos, ultraestruturais, histotológicos e moleculares de cinco novas espécies de mixosporídeos, sendo uma do gênero Henneguya em pintado, duas do gênero Myxobolus infectando dourado e duas infectando matrinxã. Henneguya sp. n. 1 apresentou plasmódios brancos e alongados no tecido conjuntivo das brânquias de pintado. A análise ultraestrutual revelou a parede plasmodial com delicadas projeções em direção aos tecidos do hospedeiro e a presença de uma fina camada de material finamente granular isolando o parasito do contato com o tecido do hospedeiro. A análise histológica revelou que o desenvolvimento do plasmódio causou a compressão no tecido conjuntivo e epitelial, deformação dos filamentos e a fusão lamelar. A análise filogenética, baseada no gene 18S rDNA e utilizando somente espécies dos gêneros Henneguya e Myxobolus parasitos de siluriformes, revelou o agrupamento de acordo com a família dos peixes hospedeiros. Myxobolus sp. n. 1 apresentou plasmódios brancos e arredondados entre os raios da nadadeira de dourado. A análise ultraestrutural revelou uma camada de fibroblastos circundando o plasmódio, impedindo o contato com as células do hospedeiro. Myxobolus sp. n. 2 apresentou plasmódios brancos e arredondados no fígado de dourado. Myxobolus sp. n. 3 e Myxobolus sp. n. 4 apresentaram plasmódios brancos e arredondados, sendo que a primeira ocorreu no baço e a segunda no rim de matrinxã. A análise ultraestrutural de Myxobolus sp. n. 2, Myxobolus sp. n. 3 e Myxobolus sp. n. 4 revelou o contato direto entre a parede do plasmódio do parasito e o tecido dos hospedeiros. As paredes dos plasmódios das cinco espécies aqui estudadas foram compostas por membrana simples. O processo de esporogênese das cinco espécies foi assincrônico, com células germinativas e jovens estágios de desenvolvimento dos esporos ocorrendo na periferia do plasmódio e esporos imaturos e maduros foram observados na região central. A análise filogenética, baseado no gene 18S rDNA e usando somente espécies dos gêneros Henneguya e Myxobolus parasitos de peixes da América do Sul mais as quatro novas espécies de Myxobolus parasitas de briconídeos, mostrou a especificidade de hospedeiro e a afinidade de órgão/tecido, como um importante sinal evolutivo para Myxobolus/Henneguya
Abstract: Myxosporeans are cosmopolitan parasites and infect fish in various regions of the world. So far, are known about 2,400 species, of which the vast majority are parasites of fishes, from natural environment and fish farms, and some species responsible for high mortality rates in various parts of the world. This work aimed to study the diversity of myxosporeans of Pseudoplatystoma corruscans (pintado), Salminus franciscanus (dourado) and Brycon orthotaenia (matrinxã) from the São Francisco River, municipality of Pirapora, MG, Brazil. Morphological, ultrastructural, histological and molecular studies of five new species of myxosporeans were performed, being one species of the genus Henneguya infecting pintado, two of the genus Myxobolus infecting dourado and two infecting matrinxã. Henneguya sp. n. 1 had white and elongated plasmodia in the connective tissue of the gill filaments. The ultrastructural analysis revealed the plasmodial wall with delicate projections towards the tissues of the host, and the presence of a thin layer of fibrous material isolating the parasite of the contact with the host tissue. Histological analysis revealed that the development of the plasmodium caused compression of the connective and epithelial tissue, deformation of the filament and lamellar fusion. Phylogenetic analysis, based on 18S rDNA gene, and using only Henneguya and Myxobolus parasites of siluriformes revealed clustering according to the family of the host fish. Myxobolus sp. n. 1 had white and rounded plasmodia that developed between the fin rays of dourado. The ultrastructural analysis showed a fibroblast layer surrounding the plasmodium, preventing contact of the parasite with the host tissues. Myxobolus sp. n. 2 had white and rounded plasmodia that developed in the liver also of dourado. Myxobolus sp. n. 3 and Myxobolus sp. n. 4 infected matrinxã, being that the first had white and rounded plasmodia in the spleen and the second in the kidney. The ultrastructural analyses of Myxobolus sp. n. 2, Myxobolus sp. n. 3 and Myxobolus sp. n. 4 revealed direct contact between the plasmodial wall and the host tissue. The plasmodial wall of the five myxosporeans species subject of this study was composed by single membrane. The process of sporogenesis in these five species was asynchronous, with germ cells and young development stages of spores occurring in the periphery of the plasmodia and immature and mature spores in the central region. Phylogenetic analysis based on 18S rDNA gene and using only Henneguya and Myxobolus parasites of fish from South America plus the four new Myxobolus species parasites of bryconids, shows host specificity and organs/tissue affinity as important evolutionary signs to Myxobolus/Henneguya
Doutorado
Parasitologia
Doutora em Parasitologia

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Teixeira, Laura Helena Marcon. "Aspectos epidemiológicos da raiva animal e avaliação da diversidade de morcegos e de seus ectoparasitas na microrregião Quirinópolis, Goiás, Brasil." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3211.

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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
Pneumonia is of the main causes of death of children under 5 years of age. Several health organizations worldwide, public and private, are engaged in investigating the disease and evaluate the effectiveness of mechanisms to prevent and combat existing. Infections causing pneumonia can be avoided. However, especially in poor countries, the resources to promote prevention are scarce. Thus the combat actions need to be very efficient and effective. To ensure the effectiveness of these actions, such as vaccines, are necessary statistical information like age range, region, period, social status and history obtained through field research. This paper proposes and implements a software architecture for the construction, use and maintenance of research of childhood pneumonias. The techniques, technologies, tools and services used in defining the architecture were chosen with a focus on low cost. This way is much more feasible to use software for automated search systems by healthcare entities that have few financial resources.
As pneumonias estão entre as principais causas de morte das crianças com menos de 5 anos de idade. Várias entidades de saúde no mundo todo, públicas e privadas, estão empenhadas em investigar a doença e avaliar a eficiência dos mecanismos de prevenção e combate existentes. As infecções que causam pneumonia podem ser evitadas. No entanto, principalmente em países pobres, os recursos para promover a prevenção são escassos. Assim as ações de combate precisam ser muito eficientes e eficazes. Para garantir a efetividade dessas ações, como as vacinas, são necessárias informações estatísticas como faixa etária, região, época, condição social e histórico obtido através de pesquisa em campo. Este trabalho propõe e implementa uma arquitetura de software para construção, uso e manutenção de sistemas de pesquisa das pneumonias na infância. As técnicas, tecnologias, ferramentas e serviços utilizados na definição da arquitetura foram escolhidos com foco no baixo custo. Dessa forma fica muito mais viável a utilização de softwares para sistemas de pesquisa automatizados por entidades de saúde que possuem poucos recursos financeiros.

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Hoppe, Estevam Guilherme Lux [UNESP]. "Infecção experimental de Mazana gouazoubira (Ficher, 1814) (Cervidae: Odocoileinae) com Haemonchus contortus (Rudolphi, 1803) (Nematoda: Trichostrongyloidea)." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/103828.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A adequada compreensão dos mecanismos fisiopatológicos das doenças que afetam os animais silvestres contribui positivamente para a melhoria das condições de manutenção desses animais em cativeiro e fornece subsídios para a elaboração de planos de conservação de animais de vida livre. Diversos relatos de Haemonchus contortus em cervídeos de cativeiro e vida livre, bem como a importância desse nematódeo para a ovinocultura, motivaram o presente estudo. Inicialmente, foram determinados valores de normalidade para os parâmetros hematológicos e bioquímicos, bem como testada possível influência do sexo sobre eles. Num segundo momento, os animais foram separados em grupos e infectados experimentalmente. O processo infeccioso foi monitorado por um período de 60 dias, ao final do qual os animais foram submetidos à eutanásia e necropsiados. O processo infeccioso estabelecido, em intensidade parasitária similar à observada em animais de vida livre, não foi capaz de suscitar alterações hematológicas, bioquímicas ou anátomo-patológicas relevantes, tampouco interferir na ingestão de alimentos, sugerindo que, apesar da possibilidade de parasitismo, a infecção por H. contortus, nos níveis deste experimento, não provocam doença clínica nos animais. À luz dos dados morfométricos e parasitológicos, sugere-se uma má adaptação do H. contortus aos veados-catingueiros, apesar da possibilidade de manutenção do parasita nestes animais.
The comprehension of the pathophysiological aspects concerning wild animals’ diseases contributes favourably to the improvement of captive rearing of these animals, and also to the elaboration of conservation action plans for free-ranging animals. The diverse reports on deer parasitism by Haemonchus contortus and the importance of this nematode for sheep production motivated this research. First, reference values for haematological and biochemical parameters were determined for this species and the gender influence on them was tested. Then, the animals were divided in groups and infected. The infectious process was monitored over a 60 days period, and then the animals were killed and necropsied. The established infection, similar to natural acquired infections, was insufficient to lead to haematological, biochemical or pathological changes or interfere with food uptake. Based on this, despite the possibility of infection, H. contortus did not cause clinical disease in gray-brocket deer. Moreover, the morphometric and parasitological data suggest a maladaptation of H. contortus in this host species.

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Hoppe, Estevam Guilherme Lux. "Infecção experimental de Mazana gouazoubira (Ficher, 1814) (Cervidae: Odocoileinae) com Haemonchus contortus (Rudolphi, 1803) (Nematoda: Trichostrongyloidea) /." Jaboticabal : [s.n.], 2010. http://hdl.handle.net/11449/103828.

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Orientador: Adjair Antônio do Nascimento
Banca: Milton Hissashi Yamamura
Banca: Alessandro Francisco Talamini do Amarante
Banca: Flavio Ruas de Moraes
Banca: Rosemeri de Oliveira Vasconcelos
Resumo: A adequada compreensão dos mecanismos fisiopatológicos das doenças que afetam os animais silvestres contribui positivamente para a melhoria das condições de manutenção desses animais em cativeiro e fornece subsídios para a elaboração de planos de conservação de animais de vida livre. Diversos relatos de Haemonchus contortus em cervídeos de cativeiro e vida livre, bem como a importância desse nematódeo para a ovinocultura, motivaram o presente estudo. Inicialmente, foram determinados valores de normalidade para os parâmetros hematológicos e bioquímicos, bem como testada possível influência do sexo sobre eles. Num segundo momento, os animais foram separados em grupos e infectados experimentalmente. O processo infeccioso foi monitorado por um período de 60 dias, ao final do qual os animais foram submetidos à eutanásia e necropsiados. O processo infeccioso estabelecido, em intensidade parasitária similar à observada em animais de vida livre, não foi capaz de suscitar alterações hematológicas, bioquímicas ou anátomo-patológicas relevantes, tampouco interferir na ingestão de alimentos, sugerindo que, apesar da possibilidade de parasitismo, a infecção por H. contortus, nos níveis deste experimento, não provocam doença clínica nos animais. À luz dos dados morfométricos e parasitológicos, sugere-se uma má adaptação do H. contortus aos veados-catingueiros, apesar da possibilidade de manutenção do parasita nestes animais.
Abstract: The comprehension of the pathophysiological aspects concerning wild animals' diseases contributes favourably to the improvement of captive rearing of these animals, and also to the elaboration of conservation action plans for free-ranging animals. The diverse reports on deer parasitism by Haemonchus contortus and the importance of this nematode for sheep production motivated this research. First, reference values for haematological and biochemical parameters were determined for this species and the gender influence on them was tested. Then, the animals were divided in groups and infected. The infectious process was monitored over a 60 days period, and then the animals were killed and necropsied. The established infection, similar to natural acquired infections, was insufficient to lead to haematological, biochemical or pathological changes or interfere with food uptake. Based on this, despite the possibility of infection, H. contortus did not cause clinical disease in gray-brocket deer. Moreover, the morphometric and parasitological data suggest a maladaptation of H. contortus in this host species.
Doutor

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Arias, Pacheco Carmen Andrea. "Parasitas e seu impacto no chaccu de vicunhas em comunidades andinas no Peru : Uma abordagem One Health /." Jaboticabal, 2020. http://hdl.handle.net/11449/192854.

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Orientador: Estevam Guilherme Lux Hoppe
Resumo: As vicunhas (Vicugna vicugna) são camelídeos sul-americanos silvestres adaptados às rigorosas condições climáticas da Cordilheira dos Andes. Esses animais possuem uma das fibras animais mais finas do mundo e de grande valor econômico. O estudo das doenças parasitárias que afetam a saúde e produtividade da espécie é o primeiro passo na implementação de medidas preventivas, programas de controle e educação em saúde. Nosso objetivo é descrever a população parasitária de vicunhas de três comunidades andinas e sua relação com a qualidade das fibras usando 115 amostras de fezes e 22 de fibra, além de registros de sexo, idade, escore de condição corporal e sistema de manejo. O diagnóstico coproparasitológico revelou que 84,4% dos animais apresentaram pelo menos um tipo de ovo/oocisto de parasitas, sendo os ovos de estrongilídeos (54,8%) e os oocistos de Eimeria punoensis (38,3%) os mais frequentes. As vicunhas silvestres apresentaram maior prevalência de ovos estrongilídeos (91,4%) do que os animais semicativos (38,8%), e a idade foi significativa para a infecção por Eimeria spp., já que as crias (100%) tiveram a maior frequência quando comparadas aos animais juvenis (84,2%) e adultos (49,4%). A identificação de larvas revelou uma forte influência de animais domésticos na comunidade de parasitas da vicunha, apresentando o primeiro relato de Bunostomum phlebotomum e Gaigeria pachyscelis em vicunhas do sudeste Peru. O diâmetro de fibra das fêmeas (13,05 ± 0,73 μm) foi significativamen... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The vicunhas (Vicugna vicugna) are wild Neotropical camelids adapted to the harsh climatic conditions of the Andes. These animals have one of the finest animal fibers in the world and an important position in the international market. Studies of parasitic diseases affecting animal health and productivity are the first step in the implementation of preventive measures, control programs and health education. We aim to describe the parasite population of vicuñas from three Andean communities and its relationship with fibre quality using 115 fecal and 22 fibre samples, records of sex, age, body condition score, and management system. Coproparasitologic diagnostic revealed that 84.4% of animals presented at least one type of parasite egg/oocyst. Most frequent parasite egg/oocyst were Strongyle-type eggs (54.8%) and Eimeria punoensis (38.3%). Wild vicuñas had a higher prevalence of Strongyle-type eggs (91.4%) than semi-captive (38.8%) animals, and age was significative to Eimeria infection, crias (100%) had the highest frequency when compared to yearlings (84.2%) and adults (49.4%). Larvae identification revealed a strong influence of domestic animals on vicuña parasite community, presenting the first report of Bunostomum phlebotomum and Gaigeria pachyscelis in vicuñas from Southeastern Peru. Females had a significantly finer diameter of fibre (13.05 ± 0.73 µm) than males (14.22 ± 1.22 µm), and infection with Eimeria spp. affected negatively fibre diameter and resistance. Our resul... (Complete abstract click electronic access below)
Mestre

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Li, Dongmei. "Immune reactions involved in parasitoid-host interactions /." Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phl6926.pdf.

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DEBOLT, JACK WARNER. "PARASITIZATION OF LYGUS LINEOLARIS (HEMIPTERA: MIRIDAE) BY LEIOPHRON UNIFORMIS (HYMENOPTERA: BRACONIDAE): HOST DEFENSE AND HOST ACCEPTANCE." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184000.

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The ability of Leiophron uniformis (Gahan) to parasitize 4 Lygus spp. was determined. While L. uniformis readily attacked Lygus hesperus (Knight), L. lineolaris (Palisot de Beauvois), L. elisus Van Duzee, and L. desertinus Knight, only 6.7% of the L. lineolaris attacked were parasitized compared to 84-87% parasitization of the other species. Two factors were found to cause the low rate of parasitism of L. lineolaris. L. uniformis oviposited in (accepted) few of the L. lineolaris nymphs attacked and most eggs found were encapsulated by the host. Nymphs less than 48-hr old were readily parasitized because they were accepted by the wasps and the hosts encapsulated few of the parasitoid eggs. As nymphal age increased, parasitism dropped rapidly as the acceptance of the host decreased and the host's encapsulation ability increased. Different strains of L. lineolaris were found to differ greatly in their susceptibility to parasitism, their ability to encapsulate, and their acceptance by the parasitoids. A host strain from Arizona was very resistant to parasitism, whereas a strain from Delaware (NJLBR) that had been in culture for 7 years was easily parasitized. The NJLBR strain had no encapsulating ability and it was readily accepted by L. uniformis. A recently established host strain from Delaware (DELBR) encapsulated 23-27% of the parasitoid eggs while an Arizona strain (FILBR) encapsulated 66-76% of the eggs. The DELBR nymphs were accepted in 42-43% of the attacks while the FILBR nymphs were accepted in only 5-14% of the attacks. Delaware and California parasitoid strains did not differ in their acceptance of L. lineolaris or in their ability to resist encapsulation. Rearing L. uniformis for only 1 generation on L. lineolaris did not precondition the wasps to accept that species as a host in preference to L. hesperus. L. uniformis, which had been reared on L. lineolaris for 5 or more generations, did accept that host 2.5 times as often as wasps reared on L. hesperus. The parasitoids did not known any increase in resistance to encapsulation even after they had been reared on L. lineolaris for 11 generations.

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31

Allen, Geoffrey Rowland. "Behaviour and ecology of the primary parasitoids Cotesia urabae and Dolichogenidia eucalypti (Hymenoptera: Braconidae) and their host Uraba lugens (Lepidoptera: Noctuidae)." Title page, contents and preface only, 1989. http://web4.library.adelaide.edu.au/theses/09PH/09pha425.pdf.

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32

Lima, Mariana Gomes. "Angiostrongylus cantonensis (Nematoda): estudo comparativo dos efeitos da infec??o sobre o metabolismo de Biomphalaria straminea e Biomphalaria tenagophila (Mollusca)." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/1474.

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The nematode Angiostrongylus cantonensis has gained notoriety under the public health point of view out of its endemic area in Asia, since in recent years cases of eosinophilic meningoencephalitis have been reported in other continents, such as in the Americas. In Brazil over thirty cases of this zoonotic disease have been recorded and there are reports of the presence of this nematode in 11 states. In its life cycle A. cantonensis has, along their development, need for intermediate and final host, involving predominantly molluscs and rodents, respectively, and different paratenic hosts, humans are accidental hosts. They can also infect a rich variety of terrestrial and aquatic molluscs and in this study, there were used specimens of neotropical planorbids transmitters of schistosomiasis, Biomphalaria straminea and Biomphalaria tenagophila, born and reared in the laboratoryfor experimental infection by A. cantonensis. In order to characterize the resulting physiological profile that host-parasite relationship, the host molluscs were separated into groups of infected and uninfected containing thirty molluscs per group, all made in triplicates. The investigation lasted 21 days, after the pre-patent period molluscs were dissected to collect hemolymph, removal of tissues and use the shell for calcium concentration check. The reproductive biology of both species was observed on the viability of the eggs, as well as (A) Number of eggs/ eggs mass; (B) Number of eggs/mollusc; (C) Number of eggs mass/mollusc and (D) Number of hatched molluscs/mollusc. In the hemolymph there were quantified total protein, glucose, uric acid, urea, the activity of transaminases AST and ALT, lactate dehydrogenase - LDH, and organic acids (oxalic, pyruvic, succinic and lactic). In the cephalopedal mass and digestive gland the glycogen content was measured and in the albumen gland, it was measured the galactogen. The results showed that the snails infected, of both species showed significant reduction in the viability of eggs, 50% for B. straminea and 10% for B. tenagophila. The metabolic status was also strongly affected, with mobilization of glycogen and hemolymph glucose reduction of 68% to B. straminea and 6.48% for B. tenagophila, followed by anincrease of LDH activity of 518.25% to 320.14% B. straminea and to B. tenagophila as well as the concentration of lactic acid, 5,7mM to B. straminea and 0.34 mM for B. tenagophila, and reduction in the concentration of pyruvic and succinic acids. The intense release of gluconeogenic amino acids from protein catabolism reversed the excretory pattern from uricotelic to ureotelic in both B. tenagophila and B. straminea. The tissue injury showed increase of 69% in the concentration of total proteins in the hemolymph of B. straminea and the intense activity of aminotransferases, ALT and AST, an increase of 241.26% and 360%, respectively, compared to the control group. The infection reduced by 51.57% the concentration of total circulating proteins to B. tenagophila, and increased ALT and AST activity at 310% and 280% compared to uninfected snails. The results of this study indicate that the energetic and structural metabolism of both species is strongly affected by the infection, showing the activation of an anaerobic to compensate for the depletion of glicidics stores as well as the change in the excretory pattern depending on the use of substrates protein for the production of ATP. Although studies on clinical, pathological and epidemiological neural angiostrongyliasis have been extensively carried xiii out, data on the metabolic and reproductive profile of snails infected by A. cantonensis are scarce. This pioneering study focused on species of host-parasite relationship certainly contribute to the knowledge of this interaction, as well as to the epidemiology of transmission A. cantonensis in addition to providing new subsidies which can be used in prevention and control of eosinophilic meningitis, zoonosis considered emerging in Brazil.
O nemat?deo Angiostrongylus cantonensis tem ganhado notoriedade sob o ponto de vista da sa?de p?blica fora de sua ?rea end?mica na ?sia, uma vez que nos ?ltimos anos casos de meningoencefal?te eosinof?lica v?m sendo reportados em outros continentes, como nas Am?ricas. No Brasil mais de trinta casos dessa zoonose j? foram registrados e h? relatos da presen?a desse nemat?deo em 11 estados. Em seu ciclo de vida heteroxeno A. cantonensis tem, ao longo do seu desenvolvimento, a necessidade de hospedeiro intermedi?rio e definitivo, envolvendo predominantemente, moluscos e roedores, respectivamente, al?m de v?rios hospedeiros parat?nicos, sendo o homem um hospedeiro acidental. Pode infectar uma rica variedade de moluscos terrestres e aqu?ticos e neste estudo, foram utilizadas para infec??o experimental popula??es nascidas e criadas em laborat?rio de duas esp?cies de planorb?deos neotropicais transmissores da esquistossomose mans?nica, Biomphalaria straminea e Biomphalaria tenagophila. Com a finalidade de caracterizar o perfil fisiol?gico resultante dessa rela??o hospedeiro-parasito, os moluscos hospedeiros foram separados em grupos de infectados e n?o infectados, contendo trinta moluscos por grupo, todos feitos em triplicatas. A investiga??o durou 21 dias, ao fim do per?odo pr?-patente os moluscos foram dissecados para a coleta de hemolinfa, retirada de tecidos e utiliza??o da concha para verifica??o de concentra??o de c?lcio. A oviposi??o dos moluscos de ambas as esp?cies foi observada quanto ? viabilidade dos ovos, assim como (A) N?mero de massas ov?geras/molusco; (B) N?mero de ovos/molusco; (C) N?mero de ovos/massa ov?gera e (D) N?mero de moluscos eclodidos/molusco. Na hemolinfa foram quantificadas as prote?nas totais, glicose, ?cido ?rico, ureia, a atividade das transaminases ALT e AST, lactato desidrogenase - LDH, e os ?cidos org?nicos (ox?lico, pir?vico, succ?nico e l?tico). Na massa cefalopediosa e gl?ndula digestiva, foram mensurados os conte?dos de glicog?nio e na gl?ndula de alb?men, foi mensurado o galactog?nio. Os resultados obtidos mostraram que os moluscos infectados, de ambas as esp?cies, apresentaram redu??o significativa na viabilidade dos ovos, de 50% para B. straminea e de 10% para B. tenagophila. O estado energ?tico tamb?m foi vigorosamente afetado, com mobiliza??o das reservas de glicog?nio, e queda da glicemia de 68% para B. straminea e de 6,48% para B. tenagophila, seguida de uma eleva??o na atividade da LDH de 518,25% para B. straminea e 320,14% para B. tenagophila, bem como na concentra??o do ?cido l?tico, 5,7mM para B. straminea e 0,34 mM para B. tenagophila, e redu??o na concentra??o dos ?cidos pir?vico e succ?nico. A intensa libera??o de amino?cidos gliconeog?nicos a partir do catabolismo proteico inverteu o padr?o excretor de uricot?lico para ureot?lico tanto em B. tenagophila quanto em B. straminea. A les?o tecidual mostrou eleva??o de 69% na concentra??o das prote?nas totais na hemolinfa de B. straminea, bem como a intensa atividade das aminotransferases, AST e ALT, com aumento de 241,26% e 360%, respectivamente, em rela??o ao grupo controle. A infec??o reduziu em 51,57% a concentra??o de prote?nas totais circulantes para B. tenagophila, e elevou a atividade de ALT e AST em 310% e xi 280% em compara??o com os moluscos n?o infectados. Os resultados observados neste estudo indicam que o metabolismo energ?tico e estrutural de ambas as esp?cies foi vigorosamente afetado pela infec??o, mostrando a ativa??o de uma via anaer?bia para compensar a exaust?o das reservas glic?dicas, assim como a mudan?a no padr?o excretor em fun??o da utiliza??o de substratos proteicos para produ??o de ATP. Embora, estudos sobre aspectos cl?nicos, patol?gicos e epidemiol?gicos da angiostrongil?ase neural t?m sido extensivamente realizados, dados acerca do perfil metab?lico e reprodutivo de moluscos infectados por A. cantonensis s?o escassos. Este estudo pioneiro na rela??o parasito-hospedeiro das esp?cies focadas seguramente contribuir? tanto para o conhecimento dessa intera??o, quanto da epidemiologia da transmiss?o de A. cantonensis, al?m de fornecer novos subs?dios que poder?o ser utilizados em medidas de preven??o e controle da meningite eosinof?lica, zoonose considerada emergente no Brasil

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33

Hennecke, Berthold Rembertus. "Host-pathogen interactions between the fungal pathogen Phloeospora mimosae-pigrae and Mimosa pigra, giant sensitive plant /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17081.pdf.

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34

Arnold, Markus F. F. "Host-pathogen interactions in chronic infections." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=192267.

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The BacA protein plays a key role in the symbiosis of Sinorhizobium meliloti with the leguminous plant alfalfa (Medicago sativa) and is proposed to be the transmembrane subunit of an ATP‐binding cassette (ABC) transporter. BacA homologues are also present in Brucella species, enteric bacteria (known as SbmA) and Mycobacterium tuberculosis. The S. meliloti‐alfalfa symbiosis, although beneficial to both partners, can also be viewed as a chronic infection. The M. tuberculosis BacA protein is important for M. tuberculosis for the maintenance of a chronic infection. In order to study the M. tuberculosis BacA protein a codon optimised M. tuberculosis bacA gene was synthesised and cloned into vectors for expression in an S. meliloti ΔbacA mutant. Evidence is presented that M. tuberculosis BacA sensitises an S. meliloti ΔbacA mutant towards the glycopeptide bleomycin and the truncated proline rich peptide Bac71‐16, and further that a functional ATPase domain is essential to perform BacA mediated peptide transport. The M. tuberculosis BacA protein protected an S. meliloti ΔbacA mutant from being killed by host defensins. In addition, it was determined that M. tuberculosis BacA‐mediated protection of the legume symbiont S. meliloti against legume defensins as well as mouse alveolar lavages and human ‐defensin 2 is dependent on an ATPase domain which is present in the M. tuberculosis BacA protein. M. tuberculosis encounters ‐defensins during mammalian infections in the host’s lungs and my data show that BacA is likely to be important in conferring immunity to these peptides. The mechanism of persistent infection by M. tuberculosis is therefore very reminiscent of the Sinorhizobium ‐ legume interaction. Also Salmonella enterica is able to cause asymptomatic infections and about 5% of these develop a chronic carrier state and are able to spread the pathogen. In enteric bacterial species SbmA is in close proximity to the putative lipoprotein YaiW. In this study it was determined that YaiW is exposed on the cell surface and that it is involved in the protection of E. coli and potentially Salmonella spp. against a cysteine rich host peptide. YaiW is potentially involved in swarming motility. It was also determined that an alfalfa plant infection model can distinguish between Salmonella strains forming acute and chronic infections. Staphylococcus aureus is one of the major hospital acquired and opportunistic pathogens. Asymptomatic carriers, infected with multi‐drug resistant strains (MRSA) pose a threat to immunocompromised individuals. Here, novel compounds and ways from a variety of sources have been tested for their potential antimicrobial activity against a range of multi‐drug resistant clinical S. aureus isolates. This project significantly advanced the molecular understanding of asymptomatic bacteria‐host infections and helped to understand and establish novel ways to treat infections with multi‐drug resistant clinical pathogens.

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35

Price, Amanda Jane. "Host-pathogen interactions in lentiviral post-entry restriction and nuclear import." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609671.

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36

Bhasin, Amit. "Host location cues of Culicoides spp. (Diptera: Ceratopogonidae)." Thesis, University of Aberdeen, 1996. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=232286.

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This study has investigated the nature of host derived cues used by parous female C. impunctatus in the location of blood meal hosts. Olfaction has been shown to be a vital part of the process. The responses of antennal receptors of females to a variety of host-derived volatile compounds were assessed using the EAG technique. High antennal sensitivity to olfactory cues was indicated by low thresholds for response and, taking into account the volatility of the compounds, a clear hierarchy of response was obtained in which octenol was the most stimulatory, followed by phenolics, lactic acid and finally ketones. Of particular note with regard to phenolic compounds was the finding that 3-derivatives (3-n-propylphenol & 3-methylphenol) were more stimulatory than their 4-derivatives (eg 4-methylphenol). Behavioural assays conducted within a Y-tube olfactometer showed that attraction to olfactory cues was dose dependent. Supra optimal doses which caused receptor saturation (as demonstrated in the EAG assay), also induced marked changes in behaviour with responses being either no different to random expectation, or the compound appearing to be repellent. Wind tunnel assays corroborated these findings for octenol and acetone when used in conjunction with 0.01% CO₂. Upwind flight was found to be maximal, and significantly different from responses to the CO₂ standard, at concentrations within the tunnel of 1.33x10^-8 g 1^-1 and 1.5x10^-6 g 1^-1, respectively. These concentrations are approximately those released by a bovid host for octenol and 1/1000x for acetone. Females exhibited a linear dose dependent response to increases in the concentration of CO₂ in the wind tunnel up to 0.09% whether gas was released as a plume or as a lightly turbulent cloud. However, at cloud concentrations above this, CNS mediated habituation is suggested to have arrested upwind flight.

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37

Gharbawi, W. Y. A. "Host-parasite relationships of the common goby, Pomatoschistus microps." Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637049.

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Pomatoschistus microps at Salthouse Point, Burry Inlet, Wales return to the estuary and spawn during June, the 1-group adults then disappear and presumably die but the developing juveniles become heavily parasitized with overdispersed, innocuous, encysted digenean metacercariae namely Cryptocotyle jejuna and C.lingua in subcutaneous muscle, C.concava (Heterophydae), in the body cavity, Labratrema minimus (Bucephalidae), in the liver, Timoniella imbutiforme and T.praeterita (Acanthostoidae) in subcutaneous muscle. Host weight, condition and other growth parameters do not appear to be affected by these parasites. However, declining rates of heterophyid infections after August suggest that host defence responses or hyperparasitism may kill some parasites. Gobies leave the estuary after November and, as suggested by increasing C.lingua and L.minimus infections, may migrate to overwinter near West Cross, Swansea Bay. Sixteen allozyme loci were resolved in these fish, using gel electrophoresis based on a sample of 575 fish. Five of these loci are polymorphic namely LDH, IDH, PGM-1, PGM-2 and PGI. The mean heterozygosity per locus is 0.06 - 0.004 and individual heterozygosity is not usually correlated with host growth parameters but is usually negatively correlated with parasite burden. The relationship is statistically significant, however, only with C.jejuna in September, the sole parasite species which elicits an intense melanized host defence response namely 'black spot' disease. The possible reasons for this are discussed in detail. In Pomatoschistus minutus at Oldbury, Severn Estuary, very lightly parasitized with the larvae of Ligula intestinalis (Cestoda: Pseudophyllidea) and Hysterothylacium sp. (Nematoda: Anisakidae), five of seventeen loci are polymorphic. The mean heterozygosity per locus is 0.03 - 0.014. The results provide equivocal support for the parasite version of the Red Queen hypothesis which predicts that the most heavily parasitized populations will have the highest mean heterozygosity and, within populations, individuals with least parasites will have highest heterozygosity.

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Barr, Kathryn J. "Aspects of the host-parasite relationships of Polymyxa betae." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334265.

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39

Radomiljac, Andrew M. "Santalum album L. plantations : a complex interaction between parasite and host." Murdoch University, 1998. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060818.134603.

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This thesis examines a broad spectrum of physiological and silvicultural features of the highly valued woody angiosperm hemi-parasite Santalurn album L. (Indian sandalwood) in relation to its culture in plantations in northern Western Australia. Topics covered include allometry of host and Santalum when grown as single plant pairings in both field and pot culture, nutritional interactions between Santalum and beneficial and non-beneficial hosts, deleterious influences of parasitism on plantation productivity and heartwood induction in young trees. In Western Australia sandalwood is grown in the nursery for 8 months before establishment in the field and during this time a pot host is introduced. Survival of Santalurn after field establishment and its subsequent growth were significantly affected by the time of introduction of the pot host, Alternanthera nana. Increasing the period of the Santalum : Alternanthera association in the nursery to 109 days prior to field establishment markedly increased early growth of Salztalum plantations. Introduction at 134 days prior to field establishment was detrimental to the parasite as the Alternanthera was too vigorous for the small Santalum seedlings. Santalurn plants had a lower root : shoot ratio lower when cultured with Alternanthera in the nursery prior to field establishment compared with seedlings grown without Alternanthera. Alterrzantlzera survival in the field was high when it had been grown with Santalum for 12 weeks or more in the nursery prior to field establishment. After 1 1 weeks in the field a strong negative linear relationship was shown between Santalunz root : shoot ratio and Alternarzthera dry weight, and a positive linear relationship between Salztalum DW and Alternanthera DW. In Western Australia Santalu~n is established in the field with an intermediate host which nourishes the parasite for 3-5 years before Santalum becomes dependent on its long-term host and the intermediate host dies. The relationship between Santalum and several species tested as intermediate hosts was examined by pairing Santalum seedlings with intermediate host seedlings in 25 litre pots over a 10 month period. Growth of Santalum in pot culture with three N2-fixing woody intermediate hosts (Sesbania forrnosa, Acacia traclzycarpa and A. ampliceps), the woody non N2-fixing Eucalyptus camaldulensis or without a host varied considerably between host treatments. Santalum growth was greater and root : shoot ratio lower for seedlings grown with N2-fixing hosts compared with seedlings grown with E. carnaldulensis or with no host. The root : shoot ratio of unattached Santalum increased exponentially over time, whereas for all other treatments it remained relatively constant. An assessment of the value of the hosts, termed host use efficiency, was computed as Santalum shoot DW / host shoot DW. The host use efficiency of A. trachycalpa was greater than that of the other hosts. The xylem sap of hosts and Sarztalum, and ethanolic extracts of endophytic tissue of haustoria of Santalzkm were analysed for amino acids, organic acids and sugars to determine which solutes were available in the host and which were extracted by the Santalum haustoria from different hosts. There were similarities between Santalum and legume hosts in concentration and composition of xylem sap amino acids, and in the amino acid spectra of the corresponding Santalum endophytic tissue, whereas there were low N levels in xylem sap of E. camaldulensis and dissimilarities between its amino acid composition and that of Santalum. This indicated substantial direct intake of xylem N by Santalum from legume hosts but little N from the xylem sap of E. canzaldulensis. There were high concentrations of asparagine, glutamate, aspartate and y-amino glutamate in the xylem sap of the legume hosts, while in the non-legume the most common amino acids were glutamate, aspartate, glutamine and arginine. Proline, the predominant amino acid in the xylem sap of Santalum acurninatum growing in natural vegetation (Tennakoon et al. 1997) was not detected or present in very low concentrations in Santalurn album under these conditions. in the non-legume. Xylem sap of hosts contained variable amounts of sugars (sucrose, glucose and fructose) and organic acids (fumaric, citric and malic acid), whereas that of the parasitic Santalum was dominated by fructose and malic acid. Dissimilarities in the proportional amounts of xylem-borne sugars and organic acids were particularly evident for the E. camaldulensis : Santalum partnership. Diurnal profiles of photosynthesis and transpiration of Santalum were closely similar to those for corresponding hosts, whereas the midday leaf water potential of Santalum was consistently more negative than that of corresponding hosts. Net photosynthesis and water use efficiency was lower, but transpiration rates were similar to that of corresponding hosts. Nitrogen concentrations of foliage of Santalum were higher than their hosts, and higher when on legume hosts than on E. camaldulensis, or without a host. Nitrogen concentrations of Santalum foliage was strongly correlated with net photosynthesis and water use efficiency of Santalum. 813C values of shoot dry matter of Santalum were poorly correlated with instantaneous water use efficiency of Santalum. Tissue water relations of Santalum were similar to that of water-stress tolerant species. S. formosa proved the best host followed by Acacia ampliceps and A. traclzycarpa based on dry matter gains of Santalum. Estimates of heterotrophic gain of C of Santalum when grown in association with the legume hosts over a nine week period indicate 57.9% of C was derived from A. ampliceps, 45.5% from A. trachycarpa and 34.6% fiom S. fomosa. Abundance of haustorial attachments on roots of hosts was poorly correlated to Santalum shoot DW. Root nodules of legume hosts were parasitised by a small proportion of Santalum haustoria. Sodium and phosphorus concentrations of foliage of Santalum were generally higher than that of corresponding hosts. Net gains of calcium, potassium, phosphorus and sodium in Santalum was greatest when grown in association with hosts richest in the corresponding element. Net losses or only small gains of calcium, potassium, phosphorus and sodium were recorded when Santalum was grown with E. camaldulensis or without a host suggesting that Santalum has limited ability for uptake of those minerals through its own root system. To understand the effect of hosts on the productivity of a Santalum plantation a young plantation of Santalum with three host species Cathormion umbellatum, Sesbania formosa and Acacia anuera was selected to study the relationship between host quality and distance of hosts from Santalunz on Santalum health. The selected plantation showed marked decline in health and vigour of both Santalum and hosts between years 3 and 5. Parameters of the host plants were assessed to select the best predictor of Santalunz crown health. The height and diameter growth increment of Santalum between years 3 and 5 was strongly correlated to Santalum crown health. Santaluin crown health and growth increased as host quality increased, and the distance of host fiom Santalum decreased. An index, which combined host quality and the distance of the host from that of Santalum, was a better predictor of Santalum crown health than host distance or quality alone. The age at which heartwood is initiated in Santalum album under plantation conditions in Western Australia in unknown, but in natural stands in India it occurs between 10-13 years of age (Rai 1990). A field experiment was conducted to determine the efficacy of stem injections of paraquat andlor ethrel in initiating heartwood formation in five year old Santalum trees in a plantation. Trees injected with paraquat alone had a significantly greater extension of induced heartwood, both radially and vertically, than those trees injected with ethrel alone or distilled water. Eight months after treatment with paraquat or ethrel or a combination of these chemicals induced heartwood was formed, which had high lipid, and low starch and polysaccharide concentrations compared to the sapwood. Induced heartwood from both chemical treatments and their combinations contained total volatile oil and santalol oil (alpha and beta santalol) concentrations that were equal to or greater than that of naturally formed heartwood and greater than that of sapwood. Moisture content, and concentrations of K and Mg, and in some treatments Ca of induced heartwood were significantly lower than that of sapwood. The thesis concludes with a synthesis of the findings and suggestions for future research, with special reference to mid-rotation aspects of Santaltrm plantation silviculture.

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Kneeland, Stephen C. "Identification of Fish Hosts for Wild Populations of Rare Freshwater Mussels (Lampsilis cariosa and Leptodea Ochracea) Using a Molecular DNA Key." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/KneelandSC2006.pdf.

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41

Soriano, Imelda Rizalina. "Novel inducible phytochemical defences against plant parasitic nematodes /." Title page, table of contents and summary only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phs7141.pdf.

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42

Kelly, Colleen Kay. "Host use and foraging in the parasitic plant Cuscuta subinclusa." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184543.

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Foraging theory predicts active responses by organisms upon encounter with a resource, as opposed to the passive responses of differential survivorship and growth. Stems of the parasitic plant Cuscuta subinclusa invest in resource acquisition (coil) relative to host quality in a way predicted by the marginal value theorem (MVT) in that: (1) stem coiling, the necessary antecedent and determinant of resource uptake, precedes exploitation of host materials; and (2) mean coiling on a host species is proportional to: (a) mean growth/haustorium, (b) mean biomass accumulation over the season, and (c) mean parasite growth/host individual. Coiling is correlated with growth/host individual for the 5 native host species examined, but not when a non-native species is added to the model, suggesting coiling response is a result of natural selection. Preliminary evidence indicates that coiling in C. subinclusa is induced by host bark chemicals. Resource-poor stems of C. subinclusa are more likely to coil, and coil more, than resource-rich stems, thus nutritional state of the parasite as well as host value affects foraging responses. Evidence from other experiments suggests that the costs of growth, or "search costs", may affect host acceptability. When water is readily available, transplanted C. subinclusa stems are less likely to coil on branches of Platanus racemosa. During the dry season, when cellular expansion is difficult, all p. racemosa branches were coiled upon. Large parasites are more likely to over-winter and set seed a second season, and parasites that start from over-wintered tissue are significantly larger at flowering than are those that have started from seed. Seed set is correlated with parasite size, thus linking foraging response and fitness of the plant. C. subinclusa's foraging response does not, however, predict population level patterns of host use. The principal determinant of host use by C. subinclusa is average proximity of a species to Malosma laurina. Parasite individuals infest many host species each season, but initially establish, set most seed, and over-winter only on M. laurina. Individual response of C. subinclusa contributes to the model of host use only after proximity to M. laurina is accounted for, suggesting that mechanisms maximizing exploitation of a host take effect after contact between host and parasite.

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Watters, George Murray. "Models of parasitism and hyperparasitism on Paralomis spinosissima /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9823698.

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Belmonte, da Silva Rodrigo Caetano. "Saprolegniosis : studies of the host-pathogen interaction in salmonids." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=220447.

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Saprolegnia is a fresh water fish parasite responsible for significant economic losses in the aquaculture industry worldwide. The disease caused by this organism is termed saprolegniosis, being characterized by a mycosis-like infection of gills and fish skin. Without sustainable treatments available for controlling or preventing saprolegniosis, it has become a significant problem especially for salmon farming, frequently affecting the fish after vaccination. Little is known regarding how the fish immune system responds to infection and such information is vital for developing future treatments and preventive measures to saprolegniosis. To study the immune response of Atlantic salmon to Saprolegnia, a detailed immune profile of experimentally infected presmolts was performed by analyzing the expression levels of several immunity-related genes. Infected fish exhibit a very strong inflammatory response while the majority of genes associate with the adaptive immunity were found to be down regulated. The mechanisms behind this response were then investigated: It was discovered that the cell wall of Saprolegnia can be recognized by fish immune cells, triggering an inflammatory response. A protease secreted by the parasite that has the ability to degrade fish antibodies was identified and, for the first time in an oomycete, the production of prostaglandin E2 was characterized, a molecule that was later shown to potentiate inflammatory responses while suppressing host adaptive immunity genes. Lastly two metabolic pathways of the oomycete were explored as novel targets for control, prostaglandin and sterol metabolism by the use of cyclooxygenase and CYP51 inhibitors, respectively.

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Schreiber, Maria Fernanda. "Studying the host transcriptome and the role of flagella in infections mediated by Salmonella and other pathogens." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610270.

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Wenzel, Marius. "Genomic, epigenomic and transcriptomic factors affecting host-parasite interactions in red grouse (Lagopus lagopus scotica)." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227041.

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Host-parasite interactions are extremely important drivers of evolutionary change, characterised by co-evolutionary dynamics with strong reciprocal selective pressure on both host and parasite genomes. However, little is known about the genomic basis of host-parasite interactions, particularly which genes may affect parasite susceptibility, parasite burden and the ability to resolve energetic life-history trade-offs under chronic parasite insult. This thesis examines the genomic, epigenomic and transcriptomic basis of an avian host's physiological response to chronic parasite infection. The model system throughout is the red grouse (Lagopus lagopus scotica) and its main parasite, the gastrointestinal nematode Trichostrongylus tenuis. T. tenuis is highly prevalent and imposes substantial fitness costs that affect demography and population dynamics through an impact on territorial behaviour, energy balance, fecundity and mortality. Here, the genomic architecture of variation in individual T. tenuis burden is examined via de novo identified candidate genes, genome-wide SNPs and genome-wide cytosine methylation polymorphisms. Further, molecular signatures of natural selection in identified genomic regions are examined across a landscape in northeast Scotland with heterogeneous parasite pressure. Finally, the transcriptomic response of red grouse to experimental T. tenuis infection and manipulation of testosterone titre is harnessed to identify a transcriptomic component in testosterone-driven physiological trade-offs in a sexual selection context.

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Gray, Alexander Bruce. "Host-parasite relationships in tissue cultures of sunflower and downy mildew." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72834.

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Younis, Abuelhassan Elshazly [Verfasser], and Norbert [Akademischer Betreuer] Brattig. "Identification and characterization of secreted stage-related proteins from the nematode Strongyloides ratti with putative relevance for parasite-host relationship : small heat shock proteins 17 and a homologue of the macrophage migration inhibitory factor / Abuelhassan Elshazly Younis. Betreuer: Norbert Brattig." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2011. http://d-nb.info/1020457163/34.

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Fredensborg, Brian Lund, and n/a. "Ecological interactions between the trematode parasite Maritrema novaezealandensis (Microphallidae) and its intermediate hosts in the New Zealand intertidal soft-sediment community." University of Otago. Department of Zoology, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060810.154001.

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Most, if not all, animals will at some stage in their lives encounter parasites. Some of the most widespread and abundant parasites belong to the Class Trematoda. Trematodes often have a substantial negative impact on individual intermediate host ecology. In this thesis, I investigate ecological and evolutionary consequences of the interaction between the microphallid trematode, Maritrema novaezealandensis, and its intermediate snail and crustacean hosts. Parasites often show a heterogeneous spatial distribution pattern in natural animal host populations. In this study, factors determining the spatial distribution of larval trematodes in Zeacumantus subcarinatus were investigated at two spatial scales (within and among bays). The distribution of shorebird definitive hosts explained a significant amount of the variation in the distribution of trematodes among bays. However, within a bay, other factors override the effect of bird distribution. The influence of larval trematodes on reproduction, survival and population density of Z. subcarinatus was investigated using laboratory and field studies. In the laboratory, it was found that larval trematodes induce castration and mortality of Z. subcarinatus. The field study revealed that the local prevalence of trematodes had a significant negative effect on population density of Z. subcarinatus. Through castration, trematodes act as strong selective agents on snail host life history. The effect of trematodes on life history characteristics (reproductive effort, juvenile growth, size at maturity and susceptibility to trematode infections) were investigated among natural populations of Z subcarinatus. Reproductive effort was not higher for uninfected females from populations where the risk of becoming infected was high. However, offspring from those populations were significantly larger, and laboratory-reared juveniles grew significantly faster than conspecifics from other populations. In addition, size at maturity was negatively correlated with trematode prevalence across snail populations. Z. subcarinatus thus adapts to a high local risk of trematode infection by reaching maturity early, thereby increasing the chance of reproducing. The influence of M. novaezealandensis on the survial of the amphipod host, Paracalliope novizealandiae was examined using experimental infections and field observations. The experimental infections demonstrated that parasite-induced mortality was intensity-dependent. The number of M. novaezealandensis per amphipod was too low to significantly induce host mortality in the field. However, the transmission strategy of this parasite allows it to affect host populations during weather conditions ideal for trematode transmission. Trematode strategies in the second intermediate host are important to the understanding of host-parasite co-evolution and the evolution of parasite life cycles. In this study, potential density-dependent effects at the metacercarial stage on size and fecundity of in vitro adult M. novaezealandensis was examined in both experimentally infected P. novizealandiae and naturally infected Macrophthalmus hirtipes. For this purpose, a method to excyst and cultivate M. novaezealandensis metacercariae to an egg producing stage, was developed. Naturally infected M. hirtipes also harboured larval stages of three other helminths. Crowding effects in the two crustacean hosts were expressed as a decreased volume and smaller egg production of in vitro adult M. novaezealandensis. In addition, interspecific interactions among parasite species were observed in crab hosts. The work in this thesis provides evidence that M. novaezealandensis significantly and negatively affect intermediate host ecology. The heterogeneous distribution of trematodes causes differential effects among host populations with subsequent effects on the life history of snail hosts. In addition, this study demonstrates that parasites interact within their second intermediate host with possible implications for the way parasites exploit their hosts.

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O'Callaghan, Michael George. "Studies on the systematics of the cestodes infecting the emu, Dromaius novaehollandiae (Latham, 1790) /." Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09pho151.pdf.

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Dissertations / Theses on the topic 'Parasite-host relationship'

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