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Type: Artigo
Title: Isolation of a novel Carica papaya _-amylase inhibitor with deleterious activity toward Callosobruchus maculatus
Authors: Farias, Luciana Ramalho
Costa, Fábio Teles
Souza, L.A.
Pelegrini, Patrícia Barbosa
Grossi-de-Sá, Maria Fátima
Maria Neto, Simone
Bloch Júnior, Carlos
Laumann, Raul Alberto
Noronha, Eliana Ferreira
Franco, Octávio Luiz
Abstract: Cowpea (Vigna unguiculata) is a subsistence crop for small and poor farmers from Latin America and Africa. This culture is commonly damaged by cowpea weevil (Callosobruchus maculatus), which burrow into stored seeds to fed on. Due to impact of larval predation, several plant defense studies have been developed, indicating that _-amylase inhibitors are able to impede and/or reduce bruchids digestive process. In this report, a novel _-amylase inhibitor from papaya seeds (Carica papaya) with activity against cowpea weevil enzymes was puriWed and biochemical characterized. Peeled seeds were macerated and extracted with a 0.6M NaCl and 0.1% HCl solution. Crude extract was precipitated with ammonium sulphate (100%). After dialyses, this rich fraction was applied onto a CM-Cellulose column and retained peak was submitted to an analytic reversed-phase column HPLC (Vydac C-18TP) yielding several peaks. Only one fraction, with molecular mass of 4562Da, showed signiWcant inhibitory activity against C. maculatus _-amylases. Otherwise, no inhibitory activities against mammalian _-amylases were observed. Bioassays using artiWcial seeds containing C. papaya _-amylase inhibitor rich fraction (0.5% and 1.0%) were also conduced showing that _-amylase inhibitors were able to increase larval mortality (50%) and also decrease insect fecundity and adult longevity. These results showed the presence of an _-amylase inhibitor from C. papaya seeds with high speciWcity to insect enzymes, indicating that this inhibitor probably could be used, through genetic engineering, in the construction of transgenic plants with enhanced resistance toward cowpea weevil.
Keywords: Callosobruchus maculatus
A-Amylase Inhibitor
Carica papaya
Plant defense
Citation: FARIAS, Luciana Ramalho et al. Isolation of a novel carica papaya alpha-amylase inhibitor with deleterious activity toward Callosobruchus maculatus. Pesticide Biochemistry and Physiology, v. 87, p. 255-260, 2007.
Access Type: Acesso Restrito
Document date: 2007
Appears in Collections:PPG - Revistas e Artigos Científicos

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