Enzymatic and ultrastructural changes in thoracic muscles of triatomine insects during the last stages of metamorphosis

Patricia Y. Scaraffia, María S. Remedi, Cristina Maldonado, Agustín Aoki, Nelia M.Gerez De Burgos

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11 Scopus citations


Dipetalogaster maximus and Triatoma infestans are hematophagous insects, vectors of Chagas' disease. After the last molt of their metamorphosis, from fifth instar nymph to adult, they acquire wings and the ability to fly, which is important for their dispersal. Some biochemical changes accompanying this last stage have been studied by determining activity of hexokinase (EC, fructose-6-phosphate kinase (EC, glucose-6-phosphate dehydrogenase (EC, glutamate dehydrogenase (EC, aspartate aminotransferase (EC, malate dehydrogenase (EC and glycerol-3-phosphate dehydrogenase (EC in thoracic muscle extracts of fifth instar nymphs and adults. Activity of all the enzymes, expressed in U per mg protein, was significantly higher in muscles of adults than of nymphs, except that of aspartate aminotransferase, had lower activity in adults of T. infestans. The increase of glycerol-3-phosphate dehydrogenase activity was particularly striking (30-fold), while the increase in glucose-6-phosphate dehydrogenase activity was of a lesser magnitude than those observed for other enzymes. Comparative ultrastructural studies of thoracic muscles showed that in adult preparations mitochondria were more numerous and larger in size, and presented more cristae than in muscles of fifth instar nymphs. The biochemical changes detected appear to be the expression of the adaptation of adult muscles for flight activity. Thus, adult muscles would have higher glycolytic and respiratory capacity than those of fifth instar nymphs. The operation of systems transferring hydrogen into mitochondria, especially that of the glycerophosphate shuttle, may be greatly increased in adult muscles.

Original languageEnglish
Pages (from-to)173-179
Number of pages7
JournalComparative Biochemistry and Physiology - A Physiology
Issue number2
StatePublished - Feb 1997


  • Dipetalogaster maximus
  • Triatoma infestans
  • enzymes
  • flight muscles
  • insect muscles
  • metamorphosis
  • muscle metabolism
  • muscle ultrastructure


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