The trypsin inhibitor from Entada acaciifolia seeds affects negatively the development of Mediterranean flour moth, Anagasta kuehniella.
The Mediterranean flour moth (Anagasta kuehniella) is a pest insect that attacks stored foods. The difficulty in controlling this kind of pest promotes the development of alternatives for pest control, among them the use of proteins with insecticide effect. In this work, we evaluated the role of a trypsin inhibitor purified from Entada acaciifolia seeds (EATI) on the A. kuehniella development. Different concentrations of inhibitor were added to a diet to determine its effects on insect performance. At 0.4%, the EATI decreases the larval weight and survival rates by 54.6% and 15%, respectively; in addition to the extension of the life cycle of insect. The biochemical analysis showed that the inhibitor is refractory to the digestion by midgut proteases, and led to a reduction of 32% in general proteolytic activity. A detailed analysis of the enzymatic activity revealed a decrease of 50% in trypsin activity as the chymotrypsin activity increased by 12%; possibly to compensate the commitment of the digestive process. The trypsins from the EATI-fed group stayed sensitive to the inhibition by EATI, and based on kinetic assays no new trypsin enzymes were produced as adaptation attempt. The insecticides effects observed for the EATI against this pest encourage a more in depth study of its possible long-term use as a biotechnological tool.
Department of Biochemistry, Institute of Biology, University of Campinas, Campinas 13083-970, SP, Brazil; Department of Food Technology and Public Health, Center for Biological and Health Sciences, University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil.
Caio Fernando Ramalho
CF
de Oliveira
Department of Biochemistry, Institute of Biology, University of Campinas, Campinas 13083-970, SP, Brazil.
Sergio
S
Marangoni
Department of Food Technology and Public Health, Center for Biological and Health Sciences, University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil. Electronic address: bioplant@terra.com.br.
Maria Lígia Rodrigues
ML
Macedo
D000818:Animals; D007887:Fabaceae / Q000737:chemistry*; D019476:Insect Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008018:Life Cycle Stages / Q000187:drug effects; D009036:Moths / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development*; D010936:Plant Extracts / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000494:pharmacology*
D019476:Insect Proteins; D010936:Plant Extracts; D014361:Trypsin Inhibitors; D014357:Trypsin
Anagasta kuehniella; Entada acaciifolia; Kunitz inhibitor; Protease inhibitor