Made available in DSpace on 2014-06-11T19:30:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-10-30Bitstream added on 2014-06-13T19:19:26Z : No. of bitstreams: 1 schalch_shc_dr_jabo.pdf: 1229379 bytes, checksum: b8e2410e3b10eb15e380a61c57c898cc (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Avaliou-se no presente trabalho, a eficácia anti-parasitária do praziquantel, levamisol e diflubenzuron administrados via oral, adicionados à ração e administrados a pacus (Piaractus mesopotamicus) infectados por Anacanthorus penilabiatus e Dolops carvalhoi. Foram utilizadas 19 caixas d água de 300 litros de capacidade, comportando 28 peixes em cada uma. O alimento dos peixes foi feito misturando as drogas na ração. O experimento foi conduzido em quatro colheitas realizadas, um dia antes e três, sete e 15 dias após a aplicação dos medicamentos. A alimentação dos peixes com ração contendo diflubenzuron, levamisol e praziquantel isolado ou associados em diferentes concentrações foi feita durante sete dias. Os resultados da eficácia terapêutica sugerem que simples ou associado com levamisol e praziquantel, o diflubenzuron é eficiente contra o crustáceo D. carvalhoi, demonstrando que a eficácia dos tratamentos nos dias três, sete e 15 foi de 96,2 a 100%. Contra os monogenóides as drogas não apresentaram eficácia satisfatória. Os resultados sugerem o uso do diflubenzuron para o controle de D. cavalhoi em peixes de cativeiro nas condições deste ensaio. / This assay evaluated the control efficacy of diflubenzuron, praziquantel and levamisole added to the diet of pacu (Piaractus mesoptamicus) infected with Anacanthorus penilabiatus and Dolops carvalhoi. Nineteen water tanks of 300 liters capacity were utilized with 28 fish in each one. The treatments were made by mixing the active principles in the diet. The experiment was evaluated in four harvests done one day before and three, seven and 15 days after the treatment. The medicated feeding was applied for seven days. The results of efficacy suggest that the diflubenzuron alone or associated with levamisole and praziquantel was efficient against the crustacean D. carvalhoi and the efficacy in the three, seven and 15 days evaluations ranged from 96,2 to 100%. Against the monogenean the drugs did not present efficacy. The results suggest the use of diflubenzuron for the control of D. carvalhoi in captive fishes in the conditions of this trial.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Aedes aegypti (L.), the vector of urban yellow fever and dengue, is controlled in Brazil mainly by the use of the organophosphate Temephos. Resistance to Temephos has been described in Brazil and in other countries as well. Insect Growth Regulators (IGRs), Diflubenzuron (chitin synthesis inhibitor) and Methoprene (juvenile hormone analog), are insecticides that affect the development of insects by affecting adult emergence. A. aegypti susceptibility to Diflubenzuron and Methoprene was investigated in Uberlândia, by studying the 50% and 95% lethal concentrations of both IGRs for the A. aegypti population (LC50 and LC95) and their action on the immature stages. In addition, other aspects, such as IGRs residual activity and the effect of sublethal dosages upon adult symmetry, size, weight, fecundity, fertility and longevity were investigated. The experiments were done in laboratory conditions using individuals from a colony originated from eggs collected in the urban area of Uberlândia. The number of replicates was six in all assays. The confidence level adopted in all the statistical analysis was 95%. The LC50 and LC95 of Diflubenzuron and Methoprene were 5.19 and 12.24 ppb; 19.95 and 72.08 ppb, respectively. Diflubenzuron was effective in all larvae instars and Methoprene caused greater mortality when the mosquito was exposed from the early fourth instar larvae on. Concentrations of commercial IGRs presented greater residual activity than did the technical formulations. Increased levels of fluctuating asymmetry were observed in the mosquitoes exposed to Diflubenzuron. Females treated with Methoprene showed smaller weight than did the untreated females. On the other hand, the longevity of the mosquito was reduced in the groups treated with both IGRs. The LC50 and LC95 of Diflubenzuron obtained here are compatible with the values observed for this IGR in other studies, while the LCs of Methoprene were higher than those generally reported in the literature. However, the results obtained here indicate that Diflubenzuron and Methoprene are potential tools to control this mosquito in the region of Uberlândia. / Aedes aegypti (L.), vetor da febre amarela urbana e da dengue, é controlado no Brasil utilizando-se principalmente o organofosforado Temephos. Tem-se registrado a ocorrência de resistência deste mosquito ao Temephos aqui e em outros países. Os Reguladores de Crescimento de Insetos (IGRs) Diflubenzuron (inibidor de síntese de quitina ) e Methoprene (análogo ao hormônio juvenil) são um grupo de inseticidas que afetam o desenvolvimento do inseto. A susceptibilidade de A. aegypti a estes IGRs foi investigada em Uberlândia a partir da obtenção das concentrações letais para 50% e 95% da população de mosquitos (CL50 e CL95) e sua atuação nas formas imaturas deste mosquito. Também foram investigados outros aspectos da susceptibilidade tais como, atividade residual destes IGRs e efeitos de dosagens subletais sobre a simetria, tamanho, peso, fecundidade, fertilidade e longevidade de adultos. Os experimentos foram realizados em laboratório com indivíduos de uma colônia originária de ovos colhidos na região urbana de Uberlândia. O número de réplicas dos grupos tratados e controles se manteve em seis em todos os experimentos. Foi adotado o nível de confiança de 95% em todas as análises estatísticas. As CL50 e CL95 obtidas para Diflubenzuron e Methoprene foram: 5,19 e 12,24 ppb; 19,95 e 72,08 ppb, respectivamente. Diflubenzuron mostrou-se efetivo em todos os estádios larvais, enquanto Methoprene causou maior mortalidade quando o mosquito foi exposto a partir do início do quarto estádio larval. As formulações comerciais dos IGRs apresentaram maior atividade residual que suas respectivas formulações técnicas. Níveis aumentados de assimetria flutuante foram observados nos mosquitos expostos ao Diflubenzuron. Fêmeas tratadas com Methoprene apresentaram menor peso que as não tratadas. Por outro lado, a longevidade do mosquito foi reduzida nos grupos tratados com ambos os produtos. Os valores das CL50 e CL95 registrados para Diflubenzuron estão dentro do intervalo de variação observados na literatura para este IGR. Já os valores registrados para Methoprene estão acima dos observados em outros locais, indicando uma relativa tolerância natural da população de A. aegypti de Uberlândia a este IGR. No entanto, os resultados aqui obtidos indicam Diflubenzuron e Methoprene como alternativas para o controle do vetor da dengue na região de Uberlândia. / Doutor em Imunologia e Parasitologia Aplicadas

Doctor of Philosophy / Department of Entomology / Kun Yan Zhu / Chitin metabolism represents an attractive target site for combating insect pests as insect growth and development are strictly dependent on precisely toned chitin synthesis and degradation and this process is absent in humans and other vertebrates. However, current understanding on this process and the involved enzymes is rather limited in insects. In this study, two chitin synthase genes (AgCHS1 and AgCHS2 or AgCHSA and AgCHSB), and 20 chitinase and chitinase-like genes (groups I-VIII) presumably encoding the enzymes for chitin biosynthesis and degradation, respectively, were identified and characterized in African malaria mosquito, Anopheles gambiae. Immunohistochemistry analysis and developmental stage- and tissue-dependent transcript profiling by using reverse transcription PCR, real-time quantitative PCR, and in situ hybridization revealed new information on these genes. Current understanding on chitin synthases is extended by the expression profiles such as the localization of AgCHS1 and AgCHS2 transcripts in eggs, AgCHS2 transcripts in the posterior larval midgut, AgCHS1 and AgCHS2 proteins in the compound eyes, and AgCHS2 enzyme in pupal inter-segments. Chitinase and chitinase-like genes are highly diverse in their gene structure, domain organization, and stage- and tissue-specific expression patterns. Most of these genes were expressed in several stages. However, some genes are stage- and tissue-specific such as AgCht8 mainly in pupal and adult stages, AgCht2 and AgCht12 specifically in foregut, AgCht13 exclusively in midgut. Functional analysis of each chitin synthase gene was conducted by using the chitosan/dsRNA nanoparticle-based RNA interference (RNAi) through larval feeding. The repression of the AgCHS1 transcripts which are predominantly expressed in carcass initiated from the mosquito larval feeding of dsRNA suggests the systemic nature of RNAi in mosquito larvae. In addition, silencing of AgCHS1 increased larval susceptibilities to diflubenzuron, whereas silencing of AgCHS2 enhanced the peritrophic matrix disruption and thus increased larval susceptibilities to calcofluor white or dithiothreitol. Furthermore, a non-radioactive method was adapted and optimized to examine the chitin synthase activity in mosquitoes. By using this method, diflubenzuron and nikkomycin Z show limited in vitro inhibition on chitin synthase at high concentration in cell free system, whereas no in vivo inhibition was observed.