Made available in DSpace on 2014-10-09T12:55:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:56Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:06/53634-3

Made available in DSpace on 2014-10-09T12:27:46Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:03Z (GMT). No. of bitstreams: 0 / Leishmanioses são um complexo de doenças infecciosas causadas por protozoários intramacrofágicos do gênero Leishmania, fatal se não tratadas adequadamente. Os antimoniais pentavalentes são os medicamentos de primeira escolha para o tratamento, apesar de sua toxicidade e seu mecanismo de ação pouco esclarecido. Uma terapia mais eficaz pode ser conseguida pelo direcionamento de fármacos antileishmania para os locais de infecção. Os lipossomas são vesículas lipídicas que promovem melhora na eficácia e na ação de fármacos na célula alvo. Os lipossomas são capturados preferencialmente pelas células do sistema mononuclear fagocitário (SMF). O objetivo deste estudo foi desenvolver uma formulação de antimoniato de meglumina lipossomal, constituído por fosfatidilserina e estudar sua farmacocinética em animais sadios para esclarecer seu metabolismo e distribuição. As análises quantitativas de antimônio em lipossomas demonstram que Análise por Ativação Neutrônica foi a técnica mais sensível com cerca de 100 % de precisão. Todas as formulações de lipossomas apresentaram um tamanho de diâmetro médio de 150 nm. A determinação da CE50 em macrófagos infectados mostrou que as formulações de antimoniato de meglumina encapsulado em lipossomas foram entre 10 - 63 vezes mais eficazes do que a fármaco livre, indicando maior índice de seletividade. Por microscopia de fluorescência, foi verificada uma maior internalização de lipossomas fluorescentes em macrófagos infectados durante um curto tempo de incubação em comparação com macrófagos não infectados. A biodistribuição do antimoniato de meglumina irradiado encapsulado em lipossomas contendo fosfatidilserina mostrou que a formulação lipossomal promoveu um direcionamento seletivo do antimônio para tecidos do SMF, além do que manteve as doses elevadas nos órgãos por um período prolongado. Em conclusão, estes dados sugerem que o antimoniato de meglumina encapsulado em lipossomas apresentou maior eficácia do que a fármaco não lipossomal contra a infecção por Leishmania. O desenvolvimento de formulações lipossomais pode ser uma nova alternativa para a quimioterapia de doenças infecciosas, especialmente Leishmanioses, já que são usados como sistemas carreadores para entrega sustentada e direcionada de fármacos ao local da infecção. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

M.Ing. / This work considers a dual band electronically steerable parasitic array radiator (ESPAR) antenna system. This system is designed with one actively fed radiating element and N-parasitic radiating elements. The radiation pattern can be electronically controlled by means of the loads terminating the parasitic elements. The antenna system is designed as ESPAR to have a minimum number of controlling elements thereby minimising the power consumed. The dual band operation of this antenna is for the frequency bands of the wireless local area network (WLAN), which are 2.412-2.482 GHz for IEEE 802.11b/g (known as the 2.4 GHz band) and 5.15-5.825 GHz for IEEE 802.11a (known as the 5 GHz band). In the upper band, only the 5.8 GHz sub-band was considered. The dual-band capability was targeted by conducting a structural parameter modification on the antenna system. The structural modification involves optimisation of the length of the active element, the length of the parasitic element, the distance of the parasitic element from the active element and most importantly, by application of a loading technique on the elements. The loading was done by using optimisation tools, such as fminsearch, fminbnd and the genetic algorithm. The specific circuit that was used for the loading was a series connection inductors inserted into the antenna’s elements at positions found via a global optimization.. The method used was to first identify the optimal length per specific resonant frequency and consider the optimal length with respect to both resonant frequencies. The second step was to load the three resulting optimised different monopoles, and the loading with results closest to the requirements. The optimum monopole of the three in the second step was then used as the fixed input parameter for the main optimisation of ESPAR antenna. Using a ground plane with a skirt, an acceptable return loss performance has been achieved for the antenna's main building M.J. Bembe ii block, a monopole element, in both frequency bands. The challenge was found in steering of the beam in different directions; it was then concluded that the usage of more elements could provide the necessary freedom for the optimisation process. Six elements were arranged symmetrically close to the active fed element in order to achieve a dual band resonance, with different designs meeting the requirements differently. This is the first report showing an ESPAR antenna optimisation which includes the loading of elements with lengths and distance optimisation.

Plantas parasitas são aquelas que retiram os recursos necessários para a sua sobrevivência de outras plantas (hospedeiras) por meio de uma estrutura denominada haustório, que permite que a parasita se conecte ao sistema vascular da hospedeira. As plantas podem responder ao ataque parasita ativando alguns mecanismos de defesa, dentre eles, a produção de substâncias fenólicas. Os viscos constituem um grupo de plantas parasitas aéreas pertencentes a Santalales que podem ser divididos em viscos holoparasitas ou hemiparasitas. Alguns gêneros de viscos são de importância econômica, dentre eles, Phoradendron, um gênero de visco hemiparasita. Esse trabalho teve como objetivos determinar os conteúdos de taninos, flavonoides, fenilpropanoides, carboidratos solúveis, amido, lipídeos, a razão carbono/nitrogênio e avaliar como a relação parasítica afeta o metabolismo das espécies envolvidas. Para tanto, coletou−se no município de Campanha (MG) folhas e ramos de seis indivíduos não parasitados de Tapirira guianensis (FT e RT) e, a partir de nove indivíduos parasitados de T. guianensis, foram coletados ramos e folhas de Phoradendron crassifolium (FP e RP), ramos não infestados da hospedeira e suas folhas (RNI e FRNI) e ramos infestados de T. guianensis e suas folhas (RI e FRI), sendo que ramos infestados foram divididos em região proximal, galha e distal (RPRI, RGRI e RDRI). Como principais resultados estão o aumento no teor de proantocianidinas e de carboidratos solúveis em FRNI e FRI em relação a FT. Ramos infestados sofreram redução nos conteúdos de carboidratos solúveis, amido, lipídeos, nitrogênio e substâncias fenólicas, exceto na região da galha (RGRI) em que aumentos de amido e flavonoides foram verificados. Observou-se ainda que RNI parece ter sofrido um acúmulo de substâncias fenólicas. O conjunto dos resultados obtidos mostra que P. crassifolium afeta o metabolismo primário e o secundário de T. guianensis, com influência mais pronunciada nos ramos do que nas folhas da hospedeira. Pode−se sugerir que a parasita obtêm nitrogênio e carboidratos solúveis de sua hospedeira e que pode ocorrer uma possível realocação de carbono para crescimento, desenvolvimento, manutenção e, ainda, defesa de ramos ainda não infestados. Além disso, sugere−se que o acúmulo de fenólicos em ramos não infestados (RNI) possa ser um mecanismo de defesa usado pela hospedeira com o objetivo de evitar, ou mesmo diminuir, novas infestações em ramos ainda não parasitados. / Parasitic plants are those that withdraw necessary resources for its survival from other plants (hosts) through a structure so-called haustorium which enables the parasite to connect to the host\'s vascular system. Plants can respond to the parasite attack activating some defense mechanisms, including the production of phenolic compounds. Mistletoes are a group of stem parasitic plants belonging to Santalales that can be grouped into holoparasite or hemiparasite mistletoes. Some mistletoes genera are of economic importance among them Phoradendron, a hemiparasite mistletoe. This study aimed to determine the contents of tannins, flavonoids, phenylpropanoids, soluble carbohydrates, starch, lipids, the carbon⁄nitrogen ratio and evaluate how the parasitic relationship affects the metabolism of the involved species. Were collected in Camapanha (MG) leaves and branches from six non−parasitized individuals of Tapirira guianensis, host plant (LT and BT). From nine parasitized individuals of T. guianensis were collected branches and leaves of Phoradendon crassifolium, the parasitic plant (LP and BP), non-infested host branches and their leaves (NIHB and NIHB-L) and infested branches and their leaves (IHB and IHB-L). Infested branches of T. guianensis were divided into proximal, gall, and distal regions (IHB-P, IHB-G and IHB-D). Main results were an increase in the proanthocyanidin and soluble carbohydrates content in NIHB−L and IHB−L in relation to LT. There was a reduction of soluble carbohydrate, starch, lipids, nitrogen, and phenolic compounds in infested branches, except in the gall region (IHB-G), which showed an increase of flavonoids and starch contents. It was also observed that NIHB appears to accumulate phenolic compounds. Results showed that P. crassifolium affects the primary and secondary metabolism of T. guianensis, and branches were affected more intense than the leaves. It can be suggested that the parasite withdraws nitrogen and soluble carbohydrates from its host and this could result in possible carbon relocation for growth, development, maintenance, and also defense of branches not yet infested. In addition, it could be suggested the accumulation of phenolic compounds in non−infested branches (NIHB) as a defense mechanism used by the host in order to prevent or even reduce new infestations of an individual already parasitized.

Global growth in aquaculture, referred to as the blue revolution, is seen by many to be the solution to future food scarcity. However, this growth has been accompanied by disease emergence. Disease emergence is inevitable when host populations are concentrated and densities exceed the threshold value for occurrence of outbreaks. Abalone farming is a relatively recent development and diseases of abalone are not well characterised. There have been relatively few systematic surveys of abalone diseases in the world. Much of the available information resulted from investigations of specific disease outbreaks, such as withering syndrome in California. The outstanding example of a formal survey of abalone health was conducted in Australia. A methodical survey of abalone health, encompassing all farms and including wild abalone, has never been done in South Africa. However, South Africa has for many years had a herd health program for abalone producers and this has generated the largest body of data on abalone disease occurrence in the world. Although these data have some shortcomings, it was felt that analysis could provide insights into the epidemiology of parasites in farmed Haliotis midae, as well as informing better surveillance techniques for the future. Data for abalone submitted from nine farms as part of the herd health management program during the period 1 January 2000 to 31 December 2004 were analysed. No wild abalone were included in these data and the only abalone species considered was the South African abalone or perlemoen, Haliotis midae. Data on the age of the abalone and their diet were obtained from the farms. The abalone originated from either flow through or recirculation systems. Each animal was weighed and measured at the laboratory. A standard set of tissue sections was fixed and processed for histology. Presence of parasites was recorded, as well as the sex and degree of gonad development. Once data had been captured in Excel, a series of tables was constructed from counts of infected and non infected abalone for all host and environmental factors contained in the data set. Charts of the tables were drawn. Where host and environmental factors appeared to interact, these data were also tabulated and charted. Statistical analyses of the data in Excel followed. All analyses were performed for sessile ciliates, renal coccidia, gut protozoa, digestive gland PAGE 2 OF 137 protozoa and rickettsia like prokaryotes. The rarity of trematode infections made meaningful analyses difficult. The chi square test, effect sizes and odds ratios were used to seek significant associations. When confounding and interaction were suspected, stratum specific odds ratios were calculated. The summary odds ratio used in this study was the Mantel Haenszel summary odds ratio. The Breslow Day test for interaction was performed when necessary. Confidence intervals were determined using the method of Woolf. The overall prevalence of the various parasites was very variable. Sessile ciliates were the most common, with a prevalence of 68.3%. Rickettsia like prokaryotes were found in 13.1% of animals. The other gut associated parasites were more scarce, with prevalences under five percent. Renal coccidia affected less than two percent of animals. Trematode infections were extremely rare, at a prevalence of 0.05%. The results of the chi square test showed a significant association between age and parasite prevalence for all parasites tested. Odds ratios were calculated comparing animals of 24 months and younger to those older than 24 months. In all cases, except trematode and left kidney coccidian infections, risk of parasite infection tended to increase with increasing age. For left kidney coccidian infections, risk of infection decreased with increasing age. Trends for body mass were similar to those for age, which is expected, as animals generally become larger with increasing age. A significant association between growth rate and parasite prevalence existed for some parasites. The chi square test showed a significant association between condition index and parasite prevalence for all parasites tested. A significant association between sex and parasite prevalence was found for all parasites tested. A significant association also existed between parasite prevalence and gonad development for sessile ciliates, renal coccidia and gut protozoa. There were significant differences in parasite prevalences between farms for all parasites tested. The South and West coasts were next compared using the chi square test. There were significant differences in parasite prevalences between coasts for only three of the parasites tested, namely renal coccidia, gut protozoa and rickettsia. Crude odds ratios showed that, with the exception of left kidney coccidia and trematodes, there was a greater risk of parasite infection on the West than the South coast. For left kidney coccidia, the risk was greater on the PAGE 3 OF 137 South coast. A chi square test was performed to examine the relationship between parasite prevalence in Hermanus and other areas. A significant difference was found for renal coccidia and gut associated parasites. The crude odds ratios for parasite prevalence in other areas compared to Hermanus were calculated. With the exception of sessile ciliates and trematodes, there was a greater risk of parasite infection in areas other than Hermanus. In the case of sessile ciliates, there was a greater risk within Hermanus than in other areas. Unfortunately, it was almost impossible to determine whether a seasonal effect exists for parasite prevalence from the available data. This was shown to be partly due to the effect of prevalence on individual farms. Significant differences in parasite prevalences between diets for all parasites tested were shown using the chi square test. To further test the strength of the association, odds ratios were calculated comparing only kelp and artificial feed. For right kidney coccidia and gut associated parasites, the odds ratios indicated a significantly increased risk of infection in animals receiving kelp compared to those on artificial feed. There was no difference in risk for sessile ciliates and left kidney coccidia. The majority of animals originated in flow through systems. The chi square test showed significant differences in parasite prevalences between systems for sessile ciliates, renal coccidia and rickettsia like prokaryotes. Odds ratios showed a significantly greater risk of sessile ciliate infections, but a smaller risk of left kidney coccidia, in animals in flow through systems when comparing only kelp fed animals. Age is likely to lead to increased prevalences if the risk of infection is constant over time and also if infections are retained. Physiological changes in the animals may also affect their risk of infection. A further important aspect of age in abalone relates to changes in husbandry. Increasing age may be the underlying reason for some of the prevalence patterns seen with mass and sex. The origin of the sample population was considered in terms of farm of origin as well as geographic area. Abalone production in the study area was highly concentrated, with approximately two thirds coming from six farms situated within ten kilometres of each another on the South coast and almost forty percent from Hermanus alone. The present study found no PAGE 4 OF 137 evidence of increased parasite prevalence in areas where abalone farming is concentrated. It was felt that this study could not generate much insight into seasonal occurrence, due to uneven distribution of variables between months. The relationship between diet and parasite prevalence was perhaps the most interesting aspect of this study and possible reasons for the association are explored. Lastly, the results indicated that parasite buildup in recirculation systems was not as problematical as may be expected. It is possible that the increased prevalence of left kidney coccidia in recirculation systems is linked to the resistance of the host population rather than to the dynamics of the actual system. The very low prevalence of sessile ciliates in recirculation systems could not be explained by examination of any other variable considered in this study. Overall, the prevalences of soft tissue parasites in Haliotis midae compared favourably with those found for parasites of other abalone species abroad. Measures which would tend to reduce parasite prevalence include separation of age groups and maintaining a relatively young population on the farm. Culling of underperforming animals is recommended. Kelp should not be used in animals of two years or younger. In older animals, there was still a greater risk associated with kelp than with artificial feed, but it was not as marked. Recirculation systems proved to be less associated with increased parasite prevalence than one may expect. The other major findings of this study did not lend themselves to practical application. / Dissertation (MSc)--University of Pretoria, 2010. / Production Animal Studies / unrestricted

No description available.

Malaria is the most prevalent vector-borne parasitic disease worldwide and a major cause of death from infections. There is a great need to develop a low cost vaccine for malaria to control transmission of infection and impact of disease, due to the emergence of anti-malarial resistance. Two leading blood stage malarial vaccine candidates are the apical membrane antigen-1 (AMA-1) and the merozoite surface protein-1 (MSP-1). The aim of this project is to express malarial antigens in tobacco plants via plastid transformation and deliver them by subcutaneous or oral gavage of minimally processed transplastomic tissue to evaluate their efficacy to elicit an immune response and protect against malarial infection. Transplastomic lines expressing the malarial antigens fused to the transmucosal carrier Cholera toxin B subunit (CTB-AMA-1) and CTB-MSP-1 were generated. CTB-AMA-1 and CTB-MSP-1 accumulated up to 9.5% and 2% of the total soluble protein, respectively. Chloroplast-derived CTB-AMA-1, CTB-MSP-1, or both antigens were administered to BALB/c mice orally or by subcutaneous injections. The immune response in the experimental animals compared to the control animals was found to be significant. Using an immunofluorescence assay (IFA) and immunoblot, anti-AMA-1 and anti-MSP-1 found in sera of immunized mice recognized the native parasite and the native parasite protein, respectively. Anti-malarial antibodies inhibited parasite invasion into erythrocytes by utilizing an in vitro parasite inhibition assay. Results of these investigations may lead to a cost-effective malarial vaccine, much needed in developing nations.

No description available.

No description available.

Cuscuta campestris is an obligate parasitic plant that lacks expanded leaves and roots and requires a host to complete its lifecycle. Parasite-host connections occur via an haustorium, a unique organ that acts as a bridge for the exchange of water, nutrients, macromolecules like mRNA, microRNA, and proteins, and microorganisms. Studies of Cuscuta spp. are challenging due to its dependence on the host and other host influences on the parasite. Recent research has shown intriguing aspects of Cuscuta biology like exchange genetic material with its hosts and loss of genes involved in processes such as high photosynthetic rates and defense. We developed new tools and methodologies that allow us to explore C. campestris biology in an unprecedent way. Foremost of these is an axenic method to grow C. campestris on an Artificial Host System (AHS). The AHS allows C. campestris to display its entire life cycle in vitro, including seed production. Using the AHS, we studied haustorial function, determining the role of nutrients and phytohormones on parasite haustorium development and growth, and found genes involved in haustorial function. The AHS allowed us to demonstrate the positive effect of light on C. campestris growth in the absence of a photosynthetic host and to investigate carotenoid- and ABA- related processes in the haustorial regions. We also wanted to understand how C. campestris defenses work independently from a plant host, so we studied the parasite responses to the bacterial epitope flg22 and the bacteria Peudomonas syringe. Our findings indicate that C. campestris is able to sense flg22, but its response differs from those observed in other non-parasite plants. Transcriptomic analysis revealed up-regulation of genes related to biotic and abiotic stresses, and downregulation of genes related to cuticle development. Our study contributes to understanding the C. campestris immune response in the absence of a host plant. Taken together, this research contributes novel methodologies that enable insights into C. campestris biology without the interference of a plant host on the parasite. / Doctor of Philosophy / Field dodder (Cuscuta campestris) is a parasitic plant that lacks leaves and roots and attacks a wide range of plants, such as tomato and beets. Dodders are not able to carry out full photosynthesis and thus are incapable of producing enough food or obtaining water to survive on their own, so they parasitize other plants. Dodders have developed specialized structures called haustoria that allow them to take resources directly from their hosts. Studying dodder is challenging due to the dependence of the parasite on its host, such that effects of one plant on the other are hard to disentangle. We developed new tools and methodologies that allow us to explore the biology of dodder in unprecedent ways. We developed an Artificial Host System (AHS) that allows the growth and study of dodder without involving a living host plant. Thanks to this new tool, we were able to improve understanding of the function of the haustorium, discover nutrients and growth factors that are indispensable for dodder development, and prove that dodder growth benefits from light. Using the AHS, we compared haustorial regions and shoot tips of dodder to identify genes specific to haustorial function. Additionally, we studied the responses of dodder to bacteria to understand how it reacts to microbial colonization. Our studies contribute with the development of novel methodologies that allow unprecedent discoveries into the biology of dodder. We expect that this work will promote the study of parasitic plant biology.