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The action of precocenes in milkweed bugs (Oncopeltus fasciatus) and locusts (Locusta migratoria)


The active constituents of the plant Ageratum houstonianum causing early larval instars of some insects to moult into precocious prothetelic adults are 7-methoxy-2,2-dimethylchromene and 6,7-dimethoxy-2,2-dimethylchromene1—precocenes 1 and 2 (P1, P2). P2 causes atrophy of the corpora allata (CA) in at least two species2–5 and juvenile hormone (JH) production is suppressed, simulating removal of the glands. Active CA are required for the effect of P2 in Oncopeltus5. The CA are the site of monooxygenase (MO) activity associated with JH biosynthesis6 and in appropriate conditions, those isolated from certain adult insects can effect the terminal epoxidation of endogenous E,E-methylfarnesoate to give C16JH (refs 7,8). The destructive effect of P2 on the CA, together with the finding9 that the 3,4-dihydrodiol is a significant metabolite in some insects, suggested that P2 has a specific cytotoxic action within the glands, possibly mediated by local formation of the 3,4-epoxide10. Reactive epoxides of polycyclic aromatic hydrocarbons11, bromobenzene12, or aflatoxins13, and oxidative metabolites of other xenobiotics14 have been implicated in their cytotoxic, mutagenic and/or carcinogenic effects in mammals, in some cases with support from manipulations of the critical balance between activating (oxidising) and deactivating enzymes in vivo12. We now present evidence that the action of precocenes on immature Oncopeltus and Locusta requires an oxidative bioactivation within the CA. The generation of reactive metabolites from innocuous precursors in vital tissue, if it can be linked to appropriate species and organ selectivity, offers an attractive approach to insect control.

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  1. Bowers, W. S., Ohta, T., Cleere, J. S. & Marsella, P. A. Science 193, 542–547 (1976).

    Article  ADS  CAS  Google Scholar 

  2. Unnithan, G. C., Nair, K. K. & Bowers, W. S. J. Insect Physiol. 23, 1081–1094 (1977).

    Article  Google Scholar 

  3. Pener, M. P., Orshan, L. & De Wilde, J. Nature 272, 350–353 (1978).

    Article  ADS  Google Scholar 

  4. Schooneveld, H. Experientia 35, 363–364 (1979).

    Article  CAS  Google Scholar 

  5. Unnithan, G. C. & Nair, K. K. Ann. Ent. Soc. Am. 72, 38–40 (1979).

    Article  CAS  Google Scholar 

  6. Hammock, B. D. Life Sci. 17, 323–328 (1975).

    Article  CAS  Google Scholar 

  7. Pratt, G. E., Tobe, S. S. & Weaver, R. J. Experientia 31, 120–122 (1975).

    Article  CAS  Google Scholar 

  8. Tobe, S. S. & Pratt, G. E. in The Juvenile Hormones (ed. Gilbert, L. I.) (Plenum, New York, 1976).

    Google Scholar 

  9. Ohta, T., Kuhr, R. J. & Bowers, W. S. J. agric. Food Chem. 25, 478–481 (1977).

    Article  CAS  Google Scholar 

  10. Brooks, G. T. Gen pharmac. 8, 221–226 (1977).

    Article  CAS  Google Scholar 

  11. Hulbert, P. Nature 256, 146–148 (1975).

    Article  ADS  CAS  Google Scholar 

  12. Gillette, J. R., Mitchell, J. R. & Brodie, B. B. A. Rev. Pharmac. 14, 271–288 (1974).

    Article  CAS  Google Scholar 

  13. Swenson, D. H., Lin, J. K., Miller, E. & Miller, J. A. Cancer Res. 37, 172–181 (1977).

    CAS  PubMed  Google Scholar 

  14. Rotman, A. Life Sci. 21, 891–900 (1977).

    Article  CAS  Google Scholar 

  15. Wilkinson, C. F. Adv. Envir. Sci. Technol. 6, 195–218 (1976).

    CAS  Google Scholar 

  16. Pratt, G. E. & Finney, J. R. in Crop Protection Agents—Their Biological Evaluation (ed. McFarlane, N. R.) (Academic, London, 1977).

    Google Scholar 

  17. Pratt, G. E. & Bowers, W. S. Nature 265, 548–550 (1977).

    Article  ADS  CAS  Google Scholar 

  18. Bowers, W. S. Pontificae Academiae Scientiarum Scripta Varia 41, 129–156 (1977).

    Google Scholar 

  19. Bowers, W. S. Science 161, 895–897 (1968).

    Article  ADS  CAS  Google Scholar 

  20. Pedersen, L. K. Gen. comp. Endocr. 36, 502–509 (1978).

    Article  CAS  Google Scholar 

  21. Němec, V., Chen, T. T. & Wyatt, G. R., Acta entomol. bohemoslov. 75, 285–286 (1978).

    Google Scholar 

  22. Boyd, M. R. Nature 269, 713–715 (1977).

    Article  ADS  CAS  Google Scholar 

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Brooks, G., Pratt, G. & Jennings, R. The action of precocenes in milkweed bugs (Oncopeltus fasciatus) and locusts (Locusta migratoria). Nature 281, 570–572 (1979).

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