Natural and Synthetic Allatotoxins: Suicide Substrates for Juvenile Hormone Biosynthesis

Bowers, William S.; Evans, Philip; Marsella, P. A.; Soderlund, David M.; Bettarini, Franco

doi:10.1126/science.217.4560.647

Cited by 41 publications

(20 citation statements)

References 15 publications

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“…It has been postulated that the precocenes undergo an oxidative activation forming highly reactive epoxides [17l capable of destructive alkylation of the allatal tissues. Similarly, we have suggested that the IPP could, through a similar oxidative activation, form either reactive epoxides or quinone methides capable of an identical cytotoxic action [20]. The allatal atrophy following the destruction of the parenchymal cells by allatotoxins and its subsequent invasion by connective tissue has been well established [6,7,11,27,28].…”

Section: Discussionmentioning

confidence: 96%

Comparison of structurally analogous allatotoxins on the molting and morphogenesis of Rhodnius prolixus, and the reversal of ecdysial stasis by ecdysone

Garcia¹,

Bowers

1984

Arch Insect Biochem Physiol

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The allatotoxic effect of 3-ethoxy4methoxy-6iso-pentenylphenol o n nymphal molting and metamorphosis of Rhodnius prolixus was examined. Continuous contact treatment with IPP induced the formation of precocious adults and retarded molting or initiated a permanent ecdysial stasis. Insects treated with 7-ethoxy-6-methoxy-2,2-dimethylchromene were similarly affected. Ecdysone given orally counteracted the ecdysial stasis and also reduced the duration of the molting delay caused by IPP.Key words: Rhodnius prolixus, precocious metamorphosis, allatotoxin, antijuvenile hormone activity, ecdysial stasis, precocene, ecdysone INTRODUCTIONSince the discovery of the antijuvenile hormonal compounds precocene I and I1 [1,2] a significant body of literature has accumulated detailing the action of these compounds on insects [3-51. In general, these investigations show that the precocenes inhibit development of the corpus allatum [1,2,6-81 through an induced atrophy of its parenchymal cells [9-111. The degeneration of the gland and its subsequent invasion by connective tissue terminates JH* production in vivo [l-31 and in vitro [12-l5]. Morphogenetic, 'Abbreviations: Ethoxy precocene I I = 7-ethoxy-6-methoxy-2,2-dimethyl chromene = EPII; 3-ethoxy4methoxy-6-iso-pentenylphenol = IPP; juvenile hormone = JH; prothoracicotropic hormone = PTrH.Acknowledgments:

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Section: Discussionmentioning

confidence: 96%

Comparison of structurally analogous allatotoxins on the molting and morphogenesis of Rhodnius prolixus, and the reversal of ecdysial stasis by ecdysone

Garcia¹,

Bowers

1984

Arch Insect Biochem Physiol

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“…Precocene II metabolized by monooxygenase enzymes to a highly labile epoxide may then alkylate cell macromolecules (Aizawa et al, 1985;Bowers et al, 1982). Precocene II present in H. zea larvae for days may be subject to metabolism by mixed-function oxidases in tissues other than the midgut.…”

Section: Discussionmentioning

confidence: 99%

Age‐dependent physiological responses of last instar Helicoverpa zea larvae to oral and topical application of precocene II

Binder

Bowers

1993

Entomologia Exp Applicata

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Newly-ecdysed last instar larvae of H. zea grouped into 100-, 200-, 300-, or 400-mg categories were fed diet containing precocene II or given precocene II topically on the abdomen. The time for larvae to reach a maximal weight, time to pupation, growth rate, and the amount of precocene II excreted were calculated. Younger larvae of lower weights, which were fed or topically treated with precocene II required more time to reach their maximal weight, had a lower maximal weight, a lower growth rate, and required more time to pupate than control larvae. Older larvae represented by the largest weight category were less sensitive to precocene II, had a shorter delay in reaching maximal weight, and a shorter delay in the time to pupation than control larvae; larvae in the largest weight category that were fed precocene II also had smaller decreases in the growth rate. Growth rate declines for larvae given topical doses of precocene II, however, were largest for the oldest larvae. All larvae given a single topical dose excreted precocene II for several days and were most efficient at eliminating smaller doses; larger, older larvae excreted more precocene II than smaller, younger larvae. Age-dependent responses to precocene II indicate that growth and metabolic processes, as well as xenobiotic metabolism, change in last instar larvae.* Mean time to pupation (days + SEM) for last instar larvae treated topically was analyzed by category with the Kruskal-Wallis test (c~ = 0.01). Pair-wise comparisons within each category were made (c~ = 0.01) and values with the same letter indicate means that were not significantly different. Mean time to pupation (days + SEM) for dietary treatment was analyzed by category with the Wilcoxon test (~ = 0.05) and all means in each 4 mM group were significantly higher than their control counterpart except the 400 mg category.

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“…Oncopeltus fasciatus responded to the open-chain analogues (29 b) and (29 c) but not to (29 a), whereas L. migratoria was unaffected by these compounds. Bowers et al (1982) suggested that analogue (29 c) may be oxidatively converted into the corresponding o-quinone methide, which may react directly with cellular nucleophiles rather than through the mechanistically more likely formation of precocene analogue (28 c). This mechanism is illustrated in figure 4 for the related compound (29 b).…”

Section: Insect Growth Regulatorsmentioning

confidence: 98%

Insecticide metabolism and selective toxicity

Brooks

1986

Xenobiotica

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Current research is focused on means to improve the environmental acceptability and selective toxicity of existing classes of insecticides and the search for new and species selective modes of insecticidal action. The study of species differences in metabolism and its modulation by changes in chemical structure is a vital component of this effort. The importance of metabolism is illustrated by examples from the major classes of insect control chemicals, namely organophosphorus and carbamate insecticides, DDT, pyrethroids and insect growth regulators.

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Natural and Synthetic Allatotoxins: Suicide Substrates for Juvenile Hormone Biosynthesis

Abstract: Cytotoxic agents with antijuvenile hormone activity in insects have been discovered. Their mechanism of action may involve an oxidative bioactivation into a reactive quinone methide.

Cited by 41 publications

References 15 publications

Comparison of structurally analogous allatotoxins on the molting and morphogenesis of Rhodnius prolixus, and the reversal of ecdysial stasis by ecdysone

Comparison of structurally analogous allatotoxins on the molting and morphogenesis of Rhodnius prolixus, and the reversal of ecdysial stasis by ecdysone

Age‐dependent physiological responses of last instar Helicoverpa zea larvae to oral and topical application of precocene II

Insecticide metabolism and selective toxicity

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