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Allelochemical stimulation of ecdysone 20‐monooxygenase in fall armyworm larvae
Author(s) -
Yu S. J.
Publication year - 1995
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940280406
Subject(s) - monooxygenase , ecdysone , biology , microsome , midgut , cytochrome , biochemistry , cytochrome p450 , ecdysteroid , fall armyworm , spodoptera , metabolism , enzyme , botany , larva , hormone , gene , recombinant dna
The influence of dietary allelochemical on ecdysone 20‐monooxygenase activity was studied in the fall armyworm, Spodoptera frugiperda (J.E. Smith). Feeding the indoles (indole‐3‐carbinol, indole‐3‐acetonitrile), flavonoids (flavone, β‐naphthoflavone), monoterpenes (menthol, menthone, peppermint oil), and a coumarin (xanthotoxin) to the larvae stimulated midgut microsomal ecdysone 20‐monooxygenase activity from 28 to 200% as compared with the controls. β‐Naphthoflavone was the most potent inducer among those tested. Phenobarbital, a well‐known cytochrome P450 inducer, also caused a 2‐fold increase in the microsomal ecdysone 20‐monooxygenase activity. Ecdysone 20‐monooxygenase activity was 2.7‐fold higher in the microsomal fraction than in the mitochondrial fraction isolated from larval midguts. Microsomal ecdysone 20‐monooxygenase activity was highest in the fat body, followed by the midgut and Malpighian tubules. Tissue localization and enzyme inducibility were different between ecdysone 20‐monooxygenase and xenobiotic‐metabolizing cytochrome P450 monooxygenases, including aldrin epoxidase, biphenyl hydroxylase, methoxyresorufin O ‐demethylase, 7‐ethoxycoumarin O ‐deethylase, p ‐chloro‐ N ‐methylaniline N ‐demethylase, and phorate sulfoxidase in fall armyworm larvae. © 1995 Wiley‐Liss, Inc.