• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 63
  • 13
  • 1
  • 1
  • 1
  • Tagged with
  • 84
  • 84
  • 16
  • 15
  • 13
  • 11
  • 11
  • 11
  • 9
  • 9
  • 8
  • 8
  • 8
  • 8
  • 8
  • 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.
71

Uso de Azadirachta indica A.Juss e Bacillus thuringiensis subsp. aizawai no manejo de Spodoptera frugiperda (J.E. Smith) (Lepidoptera : Noctuidae), na cultura do milho / Use of Azadirachta indica A. Juss and Bacillus thuringiensis subsp. aizawai to Spodoptera frugiperda (J.E. Smith) (Lepidoptera : Noctuidae) controle, in corn crop

LIMA, Marcileyne Pessôa Leite de 04 February 2008 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-12-02T11:16:10Z No. of bitstreams: 1 Marcileyne Pessoa Leite de Lima.pdf: 517075 bytes, checksum: b7ddab703563527f0c2b8e77f710122c (MD5) / Made available in DSpace on 2016-12-02T11:16:11Z (GMT). No. of bitstreams: 1 Marcileyne Pessoa Leite de Lima.pdf: 517075 bytes, checksum: b7ddab703563527f0c2b8e77f710122c (MD5) Previous issue date: 2008-02-04 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The synthetic insecticide is the main method used to control Spodoptera frugiperda (J.E. Smith). However, the inadequate application of the insecticide has contributed to increase costs, reduction of the natural enemies, and selection of resistant populations, among other problems. Attempting to obtain alternative control of S. frugiperda more ecologically acceptable, the present work investigated the effects of neem (Azadirachta indica A. Juss) and Bacillus thuringiensis subsp. aizawai (Bta) on S. frugiperda under laboratory, greenhouse and field conditions. In the field, the commercial formulations of Natuneem® (10 mL/L in 2005 and 15 mL/L in 2006) and Neemseto® (5 and 10 mL/L in 2005, and 10 and 15 mL/L in 2006) and the biological insecticide Xentari® (10 g/L in 2005 and 2006) were applied at 15, 30 and 45 and at 15, 25 e 35 days after plant emergency in 2005 and 2006, respectively. Thee evaluations consisted of using a scale of foliar injury from 0 to 5 prior each spray. In 2005, only Neemseto® 10 mL/L was efficient at 30 days. In 2006, Neemseto® 15 mL/L and Xentari® with average score of 0.93 and 0.98, respectively, were different from the control, which produced a score of 2.38 at 35 days after plant emergency. The greenhouse assay consisted of treatment of plants 40-days old with the insecticides Natuneem®, Neemseto® and Xentari® followed by artificial infestation with newly-hatched larvae of S. frugiperda. After 10 days, it was verified that the treatment were equally efficient, differing from the control, regarding to the injury score, as well as, the number of surviving larvae. In the last bioassays, in the laboratory, 10-days old S. frugiperda larvae were fed with corn leaves treated with the insecticides Natuneem®, Neemseto® and Xentari® at 2.5; 5.0; 7.5; 10 mL or g/mL and control (water). The effect of the insecticides increased as function of increasing concentration, causing higher larval mortality, longer period and lower larval weight. In some cases, reduction of pupa weight and viability and longevity of adults were also verified. Larvae 0-24 h old were more susceptible to the insecticides, as compared with 10-days old larvae. / A utilização de inseticidas sintéticos tem sido o principal método de controle de Spodoptera frugiperda (J.E. Smith), mas o uso inadequado tem contribuindo para o aumento do custo de produção, redução de inimigos naturais, seleção de populações resistentes, entre outros problemas. Desta forma, buscando alternativas de controle mais ecológicas, estudou-se no presente trabalho os efeitos de nim (Azadirachta indica A. Juss) e Bacillus thuringiensis subsp. aizawai (Bta) sobre S. frugiperda em experimentos de laboratório, casa de vegetação e campo. Foram testadas em campo formulações comerciais de inseticidas botânicos Natuneem® (10 mL/L em 2005 e 15 mL/L em 2006) e Neemseto® (5 e 10 mL/L em 2005, e 10 e 15 mL/L em 2006) e do inseticida biológico Bta (Xentari® 10 g/L em 2005 e 2006), aplicados aos 15, 30 e 45 e aos 15, 25 e 35 dias após a emergência das plantas em 2005 e 2006, respectivamente. Antes de cada pulverização foram atribuídas notas de 0 a 5 para as injúrias foliares. Em 2005, somente Neemseto® 10 mL/L foi eficiente aos 30 dias. Em 2006, Neemseto® 15 mL/L e Bta 10 g/L, com notas médias de 0,93 e 0,98, diferiram da testemunha, com nota 2,38, na avaliação realizada aos 35 dias. Plantas de milho, com cerca de 40 dias de idade, foram pulverizadas em casa de vegetação com os inseticidas Natuneem®, Neemseto e Bta, e posteriormente infestadas,artificialmente, com lagartas de S. frugiperda recém-eclodidas. Após 10 dias verificou-se que os tratamentos foram igualmente eficientes, diferindo da testemunha, tanto em relação às notas, quando ao número de lagartas sobreviventes. Nos últimos bioensaios lagartas de S. frugiperda com 10 dias de idade foram alimentadas com folhas de milho submersas na calda inseticida nas concentrações 2,5; 5,0; 7,5; 10 mL ou g/L e testemunha (água). Os efeitos dos inseticidas dependeram da concentração utilizada, pois provocaram mortalidade crescente das lagartas, alongaram o período e reduziram o peso larval. Em alguns casos, também, reduziram o peso e a viabilidade pupal e a longevidade de adultos. Lagartas com 0-24 h de idade foram mais susceptíveis aos inseticidas, em relação às com 10 dias de idade.
72

Resposta de Telenomus remus Nixon (Hymenoptera: Scelionidae) e Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) a voláteis de plantas e ovos de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) / Response of Telenomus remus Nixon (Hymenoptera: Scelionidae) and Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) to volatiles from plants and Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) eggs

Faria, Cristina Arantes de 30 July 2001 (has links)
Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-07-13T13:56:49Z No. of bitstreams: 1 texto completo.pdf: 353935 bytes, checksum: 88d19234c6373988a473eeec24e5ab38 (MD5) / Made available in DSpace on 2017-07-13T13:56:49Z (GMT). No. of bitstreams: 1 texto completo.pdf: 353935 bytes, checksum: 88d19234c6373988a473eeec24e5ab38 (MD5) Previous issue date: 2001-07-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A lagarta do cartucho Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) é uma praga polífaga de grande importância para várias culturas. Atualmente, vem sendo controlada principalmente através da utilização de inseticidas, entretanto alguns agentes de controle biológico apresentam potencial para reduzir o tamanho das suas populações, entre eles Telenomus remus Nixon (Hymenoptera: Scelionidae) e Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae), que são parasitóides de ovos de S. frugiperda. O entendimento de como os inimigos naturais de determinada praga interagem entre si e com os outros componentes do sistema é fundamental para o manejo de pragas. Dessa forma, foram realizados testes em olfatômetro de 4 braços, com o objetivo de esclarecer como T. remus e T. atopovirilia se relacionam entre si e com diferentes plantas hospedeiras. Teste 1: Avaliou os sinais que as fêmeas das duas espécies de parasitóides utilizam para localizar S. frugiperda, qual a influência de diferentes plantas hospedeiras sobre a busca dos parasitóides e se, através da detecção de diferentes sinais, há separação das guildas dos parasitóides. As fontes de odor utilizadas foram: milho, sorgo, algodão, milho + ovos de S. frugiperda, sorgo + ovos de S. frugiperda, algodão + ovos de S. frugiperda, ovos de S. frugiperda, e ovos de S. frugiperda lavados com hexano. Teste 2: Avaliou se fêmeas de T. remus e T. atopovirilia criadas massalmente, que emergem num ambiente com estímulos provenientes da cultura-alvo (milho) e do hospedeiro (fêmeas experientes), buscam o hospedeiro mais eficientemente e são mais capazes de discriminar entre plantas com e sem hospedeiros do que fêmeas que emergem em condições normais de criação massal (fêmeas inexperientes). Teste 3: Avaliou se T. remus e T. atopovirilia são arrestados da mesma forma por ovos de S. frugiperda parasitados por coespecíficos, por heteroespecíficos e não-parasitados, e se os parasitóides são capazes de discriminar entre ovos parasitados por co ou heteroespecíficos e não-parasitados. Em todos os testes, o parâmetro avaliado foi o tempo que as fêmeas gastaram em cada um dos braços do olfatômetro, sendo os resultados obtidos analisados pelos testes de Wilcoxon ou Kruskal-Wallis, seguido pelo teste de comparações múltiplas (P< 0,05). As fêmeas das duas espécies foram arrestadas por voláteis provenientes das plantas hospedeiras, plantas hospedeiras + ovos, e ovos de S. frugiperda, não sendo arrestadas pelos ovos de S. frugiperda lavados com hexano. Isso indica que as fêmeas utilizam voláteis provenientes de várias plantas hospedeiras e do hospedeiro para sua localização. O fato das fêmeas não terem sido arrestadas por ovos lavados com hexano significa que o(s) composto(s) presente(s) na superfície dos ovos e que são responsáveis pelo arrestamento dos parasitóides, são solúveis nessa substância. Comparando-se as respostas das fêmeas das duas espécies, é possível perceber que não houve diferenças de arrestamento das fontes milho, sorgo, algodão, ovos e ovos lavados, entre elas. Entretanto as fêmeas de T. remus foram significativamente mais arrestadas pelas fontes milho+ovos, sorgo+ovos e algodão+ovos do que as fêmeas de T. atopovirilia, o que indica que semioquímicos do complexo planta+hospedeiro são usados mais eficientemente por T. remus. Quando as fêmeas de T. remus e T. atopovirilia tiveram a chance de escolher entre plantas com e sem posturas, ambas preferiram plantas com postura, exceto T. atopovirilia em sorgo. Isso indica que os parasitóides são capazes de discriminar, utilizando voláteis, áreas com e sem hospedeiros, dessa forma otimizando a busca. Quando tiveram a oportunidade de escolher entre voláteis provenientes de milho, sorgo e algodão, as duas espécies apresentaram respostas semelhantes, indicando que pequenas diferenças interespecíficas na resposta a voláteis de diferentes plantas hospedeiras podem fazer com que haja redução na sobreposição das guildas das duas espécies. Nos testes de aprendizagem foi observado que fêmeas experientes e não-experientes respondem da mesma forma à planta de milho com ovos. Entretanto, quando têm a possibilidade de escolher entre plantas com e sem ovos, as fêmeas de T. remus, ao contrário das fêmeas de T. atopovirilia experientes, são significativamente mais arrestadas para plantas de milho com ovos do que fêmeas inexperientes, indicando que ocorre aprendizagem em T. remus no momento da emergência. O fato de que esse mecanismo torna a busca pelo hospedeiro mais eficiente faz com que seja um método potencial para melhorar o controle promovido por essa espécie de parasitóide. Com relação ao reconhecimento à distância de ovos parasitados intra e interespecificamente, fêmeas das duas espécies foram arrestadas da mesma forma por ovos parasitados por co ou heteroespecíficos e ovos não-parasitados. Além disso, quando estavam na presença de voláteis provenientes de ovos parasitados intra ou interespecificamente e ovos não-parasitados, não houve diferença no arrestamento dos dois tipos de ovos. Isso indica que as substâncias utilizadas para marcar ovos parasitados só atuam à curta distância, o que pode ser explicado pelo fato de que os marcadores que atuam à longa distância podem tornar os hospedeiros marcados mais conspícuos para hiperparasitóides e predadores, sendo dessa forma detrimentais para a espécie. / The fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an important pest for many crops and has been controlled by the use of pesticides. However it can be potentially controlled by the use of natural enemies like Telenomus remus Nixon (Hymenoptera: Scelionidae) and Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae), egg parasitoids of S. frugiperda. Nowadays it is known that the understanding of how the natural enemies of a pest interact among each other and with the other components of the system, have main importance to the pest management. Hence experiments to discover how T. remus and T. atopovirilia interact between each other and with different host plants were performed in a 4 way olfactometer. Test 1: Assessed which cues the females of the two parasitoid species use to find S. frugiperda, how different host plants influenced the parasitoid search and if the parasitoid guilds are separated through the detection of different cues. The odour sources used were: corn, sorghum, cotton, corn + S. frugiperda eggs, sorghum + S. frugiperda eggs, cotton + S. frugiperda eggs, S. frugiperda eggs, and S. frugiperda eggs washed with hexane. Test 2: Assessed if massal raised females of T. remus and T. atopovirilia that emerge in an environment with stimuli from the target pest and crop (experienced females) search for the host more efficiently and are more able to distinguish between plants with and without the host than females that emerge in normal conditions of massal raising (inexperienced females). Test 3: Assessed if T. remus and T. atopovirilia are attracted by eggs parasitized by conspecific, heterospecific and non parasitized; and if the females are able to distinguish between eggs parasitized by con or heterospecifics and non parasitized. For all the tests the parameter evaluated was the time spent in each arm of the olfactometer. The results were analysed by the Wilcoxon test or Kruskal-Wallis test followed by the multiple comparison test (P< 0.05). The females of both species were attracted by volatiles from the host plants, host plants+eggs and S. frugiperda eggs; and were not attracted by the S. frugiperda eggs washed with hexane. It indicates that the parasitoid females use volatiles from many host plants and from the host in the search process. The fact that the females were not attracted by eggs washed with hexane means that the compound(s) on the egg surface that are responsible for the parasitoid attraction are soluble in this substance. By comparing the responses of the females of the two species it is possible to notice that the attractivity of corn, sorghum, cotton, eggs, and eggs washed with hexane were the same for both species. However the females of T. remus were more attracted by corn+eggs, sorgum+eggs and cotton+eggs than T. atopovirilia. It means that the cue plant+host is more efficiently used by T. remus. When the females of T. remus and T. atopovirilia had the chance to choose between plants with and without eggs, both preferred plants with eggs except T. atopovirilia on sorghum. It means that the parasitoids are able to distinguish, through volatiles, areas with and without host, hence optimising the search. When they had the chance to choose among volatiles from corn, sorghum and cotton, the two species showed a slightly different behaviour, indicating that interespecific differences in the responses to volatiles from host plants may cause a reduction of the superposition of the two parasitoids guilds. On the learning tests it was observed that experienced and inexperienced females show the same responses to corn plants with eggs. However when they can choose between plants with and without eggs, experienced T. remus females (but not experienced T. atopovirilia females) are more attracted to plants with eggs than inexperienced females, indicating that a learning process occurs in emergence in T. remus, and as this mechanism makes the T. remus search more efficient, it can be used to increase the level of control promoted by this parasitoid in the field. Concerning the ability to recognise at long range eggs parasitized intra and interespecifically, the females of both species were attracted in the same way by eggs parasitized by con or heterospecifics and non parasitized. Moreover, they could not distinguish between the odour of eggs parasitized intra or interespecifically and nonparasitized eggs, when they were in presence of both types. It means that the substances used to mark parasitized eggs are only perceived at short range or by contact. It can be explained by the fact that marks that could be perceived at long range would make the parasitized hosts more conspicuous to hyperparasitoids and predators, thus being detrimental to the parasitoid. X / Dissertação importada do Alexandria
73

Molecular characterization of fall armyworm (Spodoptera frugiperda) resistant to Vip3Aa20 protein expressed in corn / Caracterização molecular da lagarta do cartucho (Spodoptera frugiperda) resistente a proteína Vip3Aa20 expressa em milho

Fatoretto, Júlio César 27 April 2017 (has links)
Transgenic plants containing genes from Bacillus thuringiensis have been used as an alternative to chemical insecticides for insect pest control. The vegetative insecticidal proteins (Vip) secreted during the vegetative growth phase of bacteria are considered a second generation of insecticidal proteins since they do not share any structural or sequence homology with previously used crystal proteins (Cry) as well as having a wide insecticidal spectrum. One of the target pests for this protein is the fall armyworm (FAW) (Spodoptera frugiperda), the most important corn pest in South America. Previously it has been controlled by insecticides and maize expressing Cry proteins, but has rapidly evolved resistance to many control practices and remains a top concern for sustainable biotechnology control efforts. Thus, resistance characterization involving mode of action and genetics of resistance can help with Insect Resistance Management strategies, and improve the durability of control. In this dissertation, using two selected FAW population resistant to Vip3Aa20 Bt protein (Vip-R1and Vip-R2) we generated comparative proteomic and transcriptomic data among resistant and susceptible colonies. In the chapter 2, we bring FAW biology/ecology and Brazilian agriculture landscape data to support the high adaptive potential of this pest to genetically modified maize expressing Bt Cry proteins in Brazil. Proteomics studies in the chapter 3 revealed that neither Vip-R1 nor Vip-R2 showed difference between resistant and susceptible colonies either for Vip3Aa20 activation through proteolysis assay nor protein binding to the receptor. Transcriptomic sequencing and RNA-seq analysis in the chapter 4 showed strong evidence of ABC transporter genes associated with resistance as well as genes related to G-protein signaling pathway as downregulated. These results will be discussed in context of providing best management practices for managing FAW resistance to Vip, and extending the durability of Vip technology. / Plantas Transgênicas expressando genes de Bacillus thuringiensis (Bt) tem sido usadas como alternativa ao controle químico para controle de insetos praga. A proteina Vip (Vegetative Insecticide Protein) cuja secreção é realizada durante fase de crescimento da bacteria é considerada como segunda geração de proteinas inseticidas em função desta não apresentar similaridade de sequencias com todas as outras proteinas cristal (Cry), apresentando ainda maior espectro de controle de pragas. Uma das pragas alvo desta proteina é a lagarta-do-cartucho do milho (Spodoptera frugiperda), considerada a mais importante na cultura do milho na América do Sul. Larvas desta espécie foram sempre controladas com inseticidas e mais recentemente, milho expressando proteínas Cry. No entanto, esta praga tem desenvolvido resistência para várias ferramentas de controle, trazendo preocupação para a sustentabilidade das taticas de controle geradas através da biotecnologia. Dessa forma, estudos de caracterização da resistencia envolvendo modo de ação e characteristicas genéticas envolvidas com resistência pode contribuir para melhorar estratégias de Manejo de Resistencia de Insetos (IRM) e aumentar a durabilidade destas tecnologias para o controle. Nesta dissertação, foi gerado dados proteômicos e de transcriptoma comparando uma população de S. frugiperda resistente a Vip3Aa20 com a susceptivel. No capítulo 2, abordamos as características de bio-ecologia da praga associado ao sistema de cultivo suportando o alto potencial adaptativo desta espécie para hibridos de milho expressando proteinas Bt no Brazil. No capitulo 3, estudos de proteômica mostrou que Vip-R1 e Vip-R2 quando comparado com SUS, não demostraram diferenças para ativação da proteina nem ausencia de ligação da proteína com receptor de membrana no intestino do inseto. Dados de transcriptoma descritos no capitulo 5 mostrou forte evidências de que a baixa expressão de genes relacionados ao sistema transportador ABC pode estar associado com resistência bem como genes da via de sinalização das proteínas G. Estes resultados serão discutidos em um contexto para suportar boas praticas de manejo de resistência para lagarta-do-cartucho e assim estender a durabilidade da tecnologia Viptera&reg; no campo.
74

Physiological effects of conditioned medium and passage number on Spodoptera frugiperda Sf9 serum free cultures

Svensson, Ingrid January 2005 (has links)
The aim of this study was to better understand the role of conditioned medium (CM) in Spodoptera frugiperda Sf9 insect cell proliferation and recombinant protein production using the baculovirus expression system. CM was found to stimulate cell proliferation. Addition of CM and 10 kDa CM filtrate to an Sf9 culture decreased the lagphase and the maximum cell density was reached earlier than for cultures in fresh medium. The positive effect of 10 kDa CM filtrate showed that CM contains at least one small growth promoting factor. The effect was not eliminated by trypsin treatment. Addition of CM or 10 kDa CM filtrate to Sf9 cultures was found to have a negative effect on the recombinant protein production. The effect was thought to be indirect and most probably via the impact of CM on cell physiology. CM was also found to contain proteinase activity. The proteinase was identified as Sf9 cathepsin L. A proform with a molecular mass about 49 kDa and two active forms at about 39 and 22 kDa were found. The role of cathepsin L in Sf9 cultures is not yet clear. However, the knowledge of the presence of this proteinase in CM can be of great value for improving product quality and yield. Further, CM was found to have other properties as well: a concentrated fraction of CM exhibited strong antibacterial activity towards Bacillus megaterium and a weaker activity towards Escherichia coli. B. megaterium lysed rapidly after incubation in the CM fraction. Repeated subculturing of Sf9 cells provoked a switch in growth kinetics. After 30-45 passages the cells started to proliferate earlier after inoculation and addition of CM had no longer a growth stimulating effect. However, CM still stimulated growth of a culture with low passage (LP) number (up to 45 passages). High passage cells (HP cells, over 100 passages) displayed a shorter lagphase than LP cells and the culture reached the maximum cell density 24-48 h earlier. Cell cycle analysis showed that the Sf9 cells were transiently synchronised in the G2/M phase 10 h after inoculation, before proliferation was initiated. This synchronisation was more pronounced for HP cells than for LP cells, which correlated to a higher recombinant protein production in baculovirus infected HP cells than in LP cells. Synchronisation of cells in G2/M by yeastolate-limitation before infection with baculoviruses suggested that the degree of synchronisation is connected to the cell density dependent decrease in recombinant protein production of Sf9 cultures. / QC 20101222
75

Evaluation of Management Strategies for the Headworm Complex in Grain Sorghum

Dobbins, Christopher Scott 07 May 2016 (has links)
During 2013 and 2014, studies were conducted to determine the effects of Helicoverpa zea and Spodoptera frugiperda on both damage and yield of Sorghum bicolor. Results from damage ratings suggest that the amount of damage per single larva decreases as population density increases. Also, yield results suggest that one H. zea and one S. frugiperda larva per panicle results in a 3.6 and 4 percent yield loss, respectively. Additionally, a dynamic EIL was determined using crop value along with various yield potentials and control costs. Other research studies were conducted to determine the efficacy of diamide and pyrethroid insecticides on headworms when applied at midge timing for different locations and planting dates. Results suggest that diamides provide longer and better control of headworms than do pyrethroids. However, applying diamides as a preventative application at midge timing may not be economically feasible when grain prices are low.
76

Unearthing the social-ecological cascades of the fall armyworm invasion: A computer-assisted text analysis of digital news articles

Bjorklund, Kathryn January 2023 (has links)
Understanding the complex nature of social-ecological cascades, or chain reactions of events that lead to widespread change in a system, is crucial for navigating the challenges they present. Emerging pests and pathogens, such as the fall armyworm, provide an opportunity to study these cascades in greater detail. I use topic modeling of digital news articles to investigate the potential social-ecological cascades associated with the ongoing fall armyworm invasion of multiple geographic regions. My findings reveal regional thematic shifts in the popular news media discourse surrounding the fall armyworm invasion. Notably, in the discourse surrounding Oceania, I observed a pronounced focus on invasion preparation, a theme significantly more emphasized compared to regions like Africa and Asia. These regional variations shed light on some of the localized priorities in addressing this invasive species. By highlighting the significance of employing comprehensive case studies of emerging pests and pathogens, this research underscores the need for more in- depth analyses of social-ecological cascades to better manage and mitigate their impacts.
77

Plant Fungal Endosymbionts Alter Host-Parasite Relationships Between Generalist Herbivores (Lepidoptera: Noctuidae) and An Entomopathogenic Nematode

Kunkel, Brian A. 19 March 2003 (has links)
No description available.
78

Modelagem estatística e ecológica de relações tróficas em pragas e inimigos naturais / Statistical and ecological modelling of the trophic relations in pests and natural enemies

Moral, Rafael de Andrade 27 January 2014 (has links)
Diversos estudos têm sido feitos para verificar quais as relações entre a lagarta do cartucho-do-milho, Spodoptera frugiperda, bem como o curuquerê-do-algodoeiro, Alabama argillacea, e potenciais agentes de controle biológico, visto que são importantes pragas de diversas culturas. Pesquisas com parasitoides e predadores de diferentes ordens têm sido desenvolvidas, com esse propósito. A tesourinha Euborellia annulipes apresenta grande potencial, assim como o pentatomídeo Podisus nigrispinus, por serem inimigos naturais desses insetos-praga. O parasitoide Campoletis flavicincta é, também, considerado um potencial agente controlador de S. frugiperda, no campo. Quatro experimentos foram instalados e conduzidos para estudar as relações ecológicas entre as espécies citadas: i) competição entre os predadores por larvas de S. frugiperda; ii) competição entre os predadores por larvas de A. argillacea; iii) competição intraespecífica entre as ninfas dos predadores; iv) teste de preferência por larvas de S. frugiperda previamente parasitadas, ou não, por C. flavicincta. Modelos estatísticos de diferentes tipos foram ajustados aos dados obtidos. Foram utilizados modelos lineares generalizados para dados discretos univariados (contagens e proporções), modelos de análise de sobrevivência para dados de tempo até ocorrência de um determinado evento, modelos aditivos generalizados e modelos multinomiais ordinais para dados de taxas de mortalidade observadas ao longo do tempo. Para verificar a qualidade do ajuste de modelos lineares generalizados, funções que produzem gráficos meio-normais com envelope de simulação foram implementadas no software estatístico gratuito R. Observou-se que as fêmeas de E. annulipes são mais agressivas e a espécie tem vantagem competitiva sobre P. nigrispinus, podendo atuar como predadora intraguilda. Além disso, os predadores têm a capacidade de discriminar entre larvas de S. frugiperda parasitadas ou não por C. flavicincta, sendo que há evidências de que os machos evitam consumir larvas parasitadas. Já as fêmeas não têm preferência e podem consumir o parasitoide, indiretamente, ao predar uma larva parasitada, sendo que isso pode ser um fator estabilizador do sistema. Adicionalmente, a coexistência entre a praga, os predadores e o parasitoide é mais provável quando as taxas de ataque dos predadores são mais altas e a do parasitoide é mais baixa. / Several studies have verified the relations among the fall armyworm, Spodoptera frugiperda, as well as the cotton leafworm, Alabama argillacea, and potential biological control agents, as they are important pests of several crops. Research with parasitoids and predators of different orders has been developed with this purpose. The ring-legged earwig (Euborellia annulipes) shows great potential, as well as the Neotrpical stink bug (Podisus nigrispinus), as they are natural enemies of these pests. The parasitoid wasp Campoletis flavicincta is also considered a biological control agent of S. frugiperda. Four experiments were set up and conducted to characterize the ecological relations among the described species: i) competition between the predators for S. frugiperda larvae; ii) competition between the predators for A. argillacea larvae; iii) intraspecific competition among the predators\' nymphs; iv) choice tests between S. frugiperda larvae that were previously parasitised by C. flavicincta and larvae that were not. Statistical models of different types were fit to the data. Generalized linear models were used to analyse univariate discrete data (counts and proportions), survival analysis models were used to analyse time-until-event data, generalized additive models and ordered multinomial logistic models were used to analyse mortality rates through time. To assess goodness-of-fit, functions that produce half-normal plots with a simulation envelope were implemented for the open-source software R. It was observed that females of E. annulipes are less aggressive and this species has a competitive advantage over P. nigrispinus, and may act as an intraguild predator. Besides that, the predators are able to distinguish parasitised from non-parasitised S. frugiperda larvae, and there are evidence that show that males tend to avoid feeding on larvae parasitised by C. flavicincta. Females, however, have no prefference and may indirectly feed on the parasitoid when predating a parasitised larva, and this might be a stabilizing factor in this system. In addition, coexistence among the pest, predators and parasitoid is most likely when predation rates are high and parasitism rates are low.
79

Modelagem estatística e ecológica de relações tróficas em pragas e inimigos naturais / Statistical and ecological modelling of the trophic relations in pests and natural enemies

Rafael de Andrade Moral 27 January 2014 (has links)
Diversos estudos têm sido feitos para verificar quais as relações entre a lagarta do cartucho-do-milho, Spodoptera frugiperda, bem como o curuquerê-do-algodoeiro, Alabama argillacea, e potenciais agentes de controle biológico, visto que são importantes pragas de diversas culturas. Pesquisas com parasitoides e predadores de diferentes ordens têm sido desenvolvidas, com esse propósito. A tesourinha Euborellia annulipes apresenta grande potencial, assim como o pentatomídeo Podisus nigrispinus, por serem inimigos naturais desses insetos-praga. O parasitoide Campoletis flavicincta é, também, considerado um potencial agente controlador de S. frugiperda, no campo. Quatro experimentos foram instalados e conduzidos para estudar as relações ecológicas entre as espécies citadas: i) competição entre os predadores por larvas de S. frugiperda; ii) competição entre os predadores por larvas de A. argillacea; iii) competição intraespecífica entre as ninfas dos predadores; iv) teste de preferência por larvas de S. frugiperda previamente parasitadas, ou não, por C. flavicincta. Modelos estatísticos de diferentes tipos foram ajustados aos dados obtidos. Foram utilizados modelos lineares generalizados para dados discretos univariados (contagens e proporções), modelos de análise de sobrevivência para dados de tempo até ocorrência de um determinado evento, modelos aditivos generalizados e modelos multinomiais ordinais para dados de taxas de mortalidade observadas ao longo do tempo. Para verificar a qualidade do ajuste de modelos lineares generalizados, funções que produzem gráficos meio-normais com envelope de simulação foram implementadas no software estatístico gratuito R. Observou-se que as fêmeas de E. annulipes são mais agressivas e a espécie tem vantagem competitiva sobre P. nigrispinus, podendo atuar como predadora intraguilda. Além disso, os predadores têm a capacidade de discriminar entre larvas de S. frugiperda parasitadas ou não por C. flavicincta, sendo que há evidências de que os machos evitam consumir larvas parasitadas. Já as fêmeas não têm preferência e podem consumir o parasitoide, indiretamente, ao predar uma larva parasitada, sendo que isso pode ser um fator estabilizador do sistema. Adicionalmente, a coexistência entre a praga, os predadores e o parasitoide é mais provável quando as taxas de ataque dos predadores são mais altas e a do parasitoide é mais baixa. / Several studies have verified the relations among the fall armyworm, Spodoptera frugiperda, as well as the cotton leafworm, Alabama argillacea, and potential biological control agents, as they are important pests of several crops. Research with parasitoids and predators of different orders has been developed with this purpose. The ring-legged earwig (Euborellia annulipes) shows great potential, as well as the Neotrpical stink bug (Podisus nigrispinus), as they are natural enemies of these pests. The parasitoid wasp Campoletis flavicincta is also considered a biological control agent of S. frugiperda. Four experiments were set up and conducted to characterize the ecological relations among the described species: i) competition between the predators for S. frugiperda larvae; ii) competition between the predators for A. argillacea larvae; iii) intraspecific competition among the predators\' nymphs; iv) choice tests between S. frugiperda larvae that were previously parasitised by C. flavicincta and larvae that were not. Statistical models of different types were fit to the data. Generalized linear models were used to analyse univariate discrete data (counts and proportions), survival analysis models were used to analyse time-until-event data, generalized additive models and ordered multinomial logistic models were used to analyse mortality rates through time. To assess goodness-of-fit, functions that produce half-normal plots with a simulation envelope were implemented for the open-source software R. It was observed that females of E. annulipes are less aggressive and this species has a competitive advantage over P. nigrispinus, and may act as an intraguild predator. Besides that, the predators are able to distinguish parasitised from non-parasitised S. frugiperda larvae, and there are evidence that show that males tend to avoid feeding on larvae parasitised by C. flavicincta. Females, however, have no prefference and may indirectly feed on the parasitoid when predating a parasitised larva, and this might be a stabilizing factor in this system. In addition, coexistence among the pest, predators and parasitoid is most likely when predation rates are high and parasitism rates are low.
80

Purification of human recombinant Naglu from Sf9 cells and uptake studies with MPS IIIB fibroblasts

Ashmead, Rhea 15 July 2019 (has links)
Mucopolysaccharidosis IIIB (MPS IIIB) is a rare, metabolic disorder that results from a deficiency in the lysosomal hydrolase, α-N-acetylglucosaminidase (Naglu). Naglu is a housekeeping enzyme involved in the degradation pathway of heparan sulfate. A deficiency in active Naglu leads to an accumulation of heparan sulfate within the lysosome, initiating a pathological cascade within the cell. Patients with MPS IIIB experience progressive central nervous system degeneration and die within the first few decades of life. Presently, enzyme replacement therapy, which is a standard of care for other lysosomal storage disorders, is an ineffective treatment for MPS IIIB. This is due to impermeability of the blood-brain barrier (BBB) to exogenous recombinant enzymes. A promising approach to this therapeutic obstacle is protein transduction domains. Protein transduction domains have been shown to facilitate the delivery of active enzyme across the BBB in mice. Previously, our laboratory used Spodoptera frugiperda (Sf9) insect cell system to express human recombinant Naglu fused to a synthetic protein transduction domain (PTD4). The purpose was to use PTD4 to the facilitate the delivery of Naglu across biological membranes, including the blood-brain barrier. However, a missing stop codon following PTD4 limited its transducibility. The stop codon was re-introduced and the improved fusion enzyme, Naglu-PTD4X, was stably expressed in Sf9 cells. The overarching goal of this project is to create a large-scale production of human recombinant Naglu that has the potential to be used to treat the neuropathology of patients with MPS IIIB. This project used a three-step purification system to purify Naglu-PTD4X. Uptake of Naglu-PTD4X was assessed in MPS IIIB fibroblasts using a fluorogenic activity assay, immunoblotting, and immunocytochemistry. Our purification system was successful at purifying Naglu-PTD4X to homogeneity with a 26% yield and specific activity of 84,000 units/mg. An increase in Naglu activity was detected in MPS IIIB fibroblasts following incubation with Naglu-PTD4X. Future directions will focus on optimizing immunodetection and conducting BBB penetration studies in murine models. / Graduate / 2020-06-21

Page generated in 0.0546 seconds