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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Efeito da adi??o de colesterol e ecdisona na produ??o in vitro do baculov?rus spodoptera frugiperda MNPV

Dantas, Graciana Clecia 02 August 2010 (has links)
Made available in DSpace on 2014-12-17T15:01:23Z (GMT). No. of bitstreams: 1 GracianaCD_DISSERT.pdf: 963468 bytes, checksum: 406e6de21c3be72fd5a9ff01dcdda958 (MD5) Previous issue date: 2010-08-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Among the pests that attack corn crop in Brazil, there is Spodoptera frugiperda (JE Smith, 1797) (Lepidoptera: Noctuidae), known as fall armyworm, which is the major corn pest. Due to genetic instability during serial passage of baculoviruses in insect cell culture, the viral bioinseticides in vitro production development is the greatest challenge for mass production of this bioproduct. Successive passages of virus using extracellular viruses (BVs), necessary during viral bioinseticides production scaling up, leads to the appearance of aberrant forms of virus, a process so called as "passage effect ". The main consequence of passage effect is the production of occlusion bodies (OB) decrease, preventing its production using in vitro process. In this study, it was carried out a serial passage of baculovirus Spodoptera frugiperda multiple nucleopolyhedrovirus, isolate 18, using Sf21 cells. A decrease in the production of occlusion bodies from 170 to 92 in the third to fourth passage was observed. A factorial experimental design (22) was employed to verify the influence of two input variables, concentration of the hormone 20 - hydroxyecdysone (CH) and cholesterol (CC) on the values of response variables (volumetric and the specific OB production) of the process, seeking to define the optimum operating ranges trying to reverse or minimize the passage effect. The result indicated a negative influence of the cholesterol addition and positive effect in the hormone supplementation which the optimum range found for the concentrations studied were 8 to 10μg/mL and 5 to 6.5 mg / mL, for cholesterol and hormone concentrations respectively. New experiments were performed with addition of hormone and cholesterol in order to check the influence of these additives on the OB production independently. While the best result obtained from the factorial experiment was 9.4 x 107 OB/mL and 128.4 specific OB/cell, with the addition of only 6μg/mL 20-hydroxyecdysone these concentrations increased to 1.9 x 108 OB/mL and 182.9 OB/cell for volumetric and specific OB production, respectively. This result confirms that the addition of the hormone 20-hydroxyecdysone enhances the SfMNPV in vitro production process performance using Sf21 cells / Dentre as pragas que atacam a cultura do milho no Brasil, destaca-se a Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), conhecida no est?dio larval como lagarta-do-cartucho, considerada a praga chave da cultura, alimentando-se da planta em todas as suas fases de crescimento, principalmente dos cartuchos de plantas jovens. Para seu controle, tem-se empregado inseticidas qu?micos de amplo espectro, o que tem causado efeitos adversos ao homem e ao meio ambiente. Por essa raz?o, torna-se necess?ria a busca de alternativas mais eficientes, de baixo custo e de f?cil utiliza??o, como o uso de bioinseticidas, especialmente os baculov?rus. Devido ? instabilidade gen?tica durante a passagem seriada de baculov?rus em cultivo de c?lulas de inseto, o desenvolvimento da produ??o in vitro de bioinseticidas virais ? o maior desafio para a sua produ??o massal. Passagens sucessivas de v?rus usando v?rus extracelulares (BVs), necess?rias para o aumento de escala durante a produ??o de bioinseticida viral, leva ao aparecimento de formas aberrantes de v?rus, processo conhecido como efeito de passagem . A principal consequ?ncia do efeito passagem ? a diminui??o da produ??o de corpos de oclus?o (OB), inviabilizando economicamente sua produ??o pelo processo in vitro. Neste trabalho, foi realizada a passagem seriada do isolado 18 do baculov?rus Spodoptera frugiperda multiple nucleopolyhedrovirus em c?lulas Sf21. Foi observada uma queda na produ??o de OB de 170 para 92 da terceira para quarta passagem. Um planejamento experimental fatorial (22) foi empregado para verificar a influ?ncia de duas vari?veis de entrada, concentra??o de horm?nio 20- Hidroxiecdisona (CH) e concentra??o de colesterol (CC), sobre os valores das vari?veis de resposta do processo (produ??o volum?trica e produ??o espec?fica de OB), procurando definir as faixas ?timas de opera??o para reverter ou minimizar o efeito passagem. O resultado deste planejamento indicou influ?ncia negativa da adi??o do colesterol e positiva na adi??o de horm?nio, onde as faixas ?timas encontradas para as concentra??es estudadas foram: 8 a 10μg/mL e 5 a 6,5μg/mL, para as concentra??es de colesterol e horm?nio, respectivamente. Novos experimentos foram realizados com a adi??o individual de horm?nio e colesterol com a finalidade de verificar a influ?ncia destes adjuvantes na produ??o de OB de forma independente. No planejamento experimental obteve-se produ??o volum?trica de 9,4 x 107 OB/mL e espec?fica de 128,4 OB/c?lula. Quando se adicionou 6 μg/mL de 20-Hidroxiecdisona, as concentra??es elevaram-se para 1,9 x 108 OB/mL e 182,9 OB/c?lula, indicando que a adi??o do horm?nio melhorou a efici?ncia da produ??o in vitro de produ??o de SfMNPV em cultivos de c?lulas Sf21

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