Applied Biochemistry and Biotechnology

, Volume 150, Issue 3, pp 243–257

Non-Selective Toxicological Effects of the Insect Juvenile Hormone Analogue Methoprene. A Membrane Biophysical Approach

  • João P. Monteiro
  • Romeu A. Videira
  • Manuel J. Matos
  • Augusto M. Dinis
  • Amália S. Jurado

DOI: 10.1007/s12010-007-8127-6

Cite this article as:
Monteiro, J.P., Videira, R.A., Matos, M.J. et al. Appl Biochem Biotechnol (2008) 150: 243. doi:10.1007/s12010-007-8127-6


The Gram-positive bacterium, Bacillus stearothermophilus, was used as a model organism to identify the non-selective toxic effects of the currently used insecticide methoprene (isopropyl(2E,4E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate). A significant decrease of the yield of bacterial cultures and a premature appearance of ultrastructural abnormalities in cells cultured in the presence of the insecticide were taken as indicators of cytotoxicity. A putative correlation of this cytotoxicity with methoprene-induced perturbations on membrane lipid organization was investigated, using differential scanning calorimetry and the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and its propionic acid derivative (DPH–PA). The membrane physical effects depended on the lipid bilayer composition and packing. The most striking effect was a progressive broadening and shifting to lower temperatures, with increasing methoprene concentrations, of the main transition phase of the dimyristoyl- or dipalmitoylphosphatidylcholine bilayers and of the lateral phase separation of liposomes reconstituted with the lipid extracts of B. stearothermophilus.


MethopreneLipid dynamicsDifferential scanning calorimetryFluorescence polarizationCell ultrastructureBacillus stearothermophilus







3-(p-(6-phenyl)-1,3,5-hexatrienyl)phenylpropionic acid




differential scanning calorimetry


transmission electron microscopy

Copyright information

© Humana Press Inc. 2008

Authors and Affiliations

  • João P. Monteiro
    • 1
  • Romeu A. Videira
    • 2
  • Manuel J. Matos
    • 1
  • Augusto M. Dinis
    • 3
  • Amália S. Jurado
    • 1
    • 4
  1. 1.Centro de Neurociências e Biologia Celular; Department of BiochemistryUniversity of CoimbraCoimbraPortugal
  2. 2.Higher School of TechnologyPolytechnic Institute of ViseuViseuPortugal
  3. 3.Laboratório de Microscopia Electrónica, Department of BotanyUniversity of CoimbraCoimbraPortugal
  4. 4.Department of BiochemistryUniversity of CoimbraCoimbraPortugal