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| C. Ciências Biológicas - 3. Bioquímica - 6. Bioquímica | ||
| EVALUATION OF THE EFFECTS OF PROTEIN FRACTIONS FROM Luetzelburgia auriculata ON THE LARVAL DEVELOPMENT AND INSECT EMERGENCE OF Callosobruchus maculatus (COLEOPTERA: BRUCHIDAE) | ||
| Emanoella Lima Soares 1 (emanoellalimasoares@yahoo.com.br), Cleverson Diniz Teixeira de Freitas 1, Maurício P. Sales 2, José Delano M Barreto-Filho 1, Diego Pereira de Souza 1 e Márcio Viana Ramos 1 | ||
| (1. Depto. de Bioquímica e Biologia Molecular, Universidade Federal do Ceará - UFC; 2. Depto. de Bioquímica, Universidade Federal do Rio Grande do Norte - UFRN) | ||
| INTRODUÇÃO:
Legume seeds represent an important source of proteins to the poorest population living in the Northeast of Brazil. Among them cowpea (Vigna unguiculata) is largely cultivated, but this crop is target of pathogens and insect pests that causes important losses. The most important insect pest is the bruchid weevil (Callosobruchus maculatus). The insect damages mature seeds during storage. It would be of great relevance to investigate adverse effects of non-cowpea proteins on the C. maculatus development in attempt to identify protective proteins that could be candidates to be used in molecular biology programs devoted to improve cowpea resistance against insects. Luetzelburgia auriculata is a leguminous tree native of Northeast of Brazil and seeds are rich source of proteins and lipids. In the present work the effects of two protein fractions extracted from seeds of L. auriculata were evaluated upon the larval development and insect emergence of C. maculatus accessed by a bioassay using artificial seeds. |
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| METODOLOGIA:
The protein fractions albumins and globulins were prepared from the defatted seed flour according to their solubility in water and salt, respectively following classical protocols. The protein fractions were further dialyzed and lyophilized. LA-albumins and LA-globulins were thus, gently mixed with the fine seed flour of the cowpea and homogenized to represent different concentrations (0%; 0.05%; 0.1%; 0.25%; 0.5% and 1%). Such materials were encapsulated in gelatin capsules and seeds weighted ± 580 mg. Two days old fertilized females of C. maculatus were allowed to oviposite in the seeds that were incubated at 27º C and 70-75% relative humidity. After the ovipositional period the females were withdrawal and the number of eggs adjusted to five per seed. After eighteen days of incubation, samples of seeds were examined for determination of the number and weight of larvae. To determine time of development (insect emergence) the corresponding seeds were observed daily and compared to the control performance. The data were evaluated by analysis of variance (ANOVA) and submitted to linear regression. |
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| RESULTADOS:
The linear regression analysis showed a negative correlation between larval weight and concentration of both albumins and globulins in artificial seeds. Albumins differed from the control at 0.25% while globulins 1%. Regarding insect emergence, albumins showed toxicity at 0.25% with a LD50 of 0.4% while globulins were ineffective. |
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| CONCLUSÕES:
LA-albumins showed severe effect for both larval development and insect emergence while LA-globulins seemed to be detrimental only to larval development. LA-albumins could be better analyzed in order to identify the proteins involved in the toxic activity. |
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| Instituição de fomento: Supported by CNPq/PADCT, FUNCAP, and IFS. | ||
| Trabalho de Iniciação Científica | ||
| Palavras-chave: Albumins; Globulins; Callosobruchus maculatus. | ||
| Anais da 57ª Reunião Anual da SBPC - Fortaleza, CE - Julho/2005 |