Factors regulating metamorphosis in hemimetabolan insects

• Autores: Orathai Kamsoi
• Directores de la Tesis: Xavier Bellés Ros (dir. tes.)
• Lectura: En la Universitat Pompeu Fabra ( España ) en 2020
• Idioma: español
• Tribunal Calificador de la Tesis: Isabel Navarro Álvarez (presid.), José Luis Maestro Garriga (secret.), Joan Cerdà (voc.)
• Programa de doctorado: Programa de Doctorado en Biomedicina por la Universidad Pompeu Fabra
• Materias:
  • Ciencias de la vida
    • Biología de insectos (entomología)
      • Desarrollo de los insectos
      • Fisiología de los insectos
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• Resumen

  • The present thesis deals with the mechanisms regulating metamorphosis, particularly in hemimetabolan insects, by using the cockroach Blattella germanica and the mayfly Cloeon dipterum, as models. We have examined possible candidates to regulate different aspects of metamorphosis, chosen in some cases on the basis of transcriptomic data of B. germanica available in our laboratory. Then, we have functionally tested them with RNAi. Moreover, we have also studied the mayfly Cloeon dipterum, a species belonging to Palaeoptera, an early-branching insect group of which very little is known about metamorphosis and its regulatory mechanisms. In this case, we have examined the expression of key genes that are involved in metamorphosis in neopteran insects, and we have approached the functional studies through treatments with a juvenile hormone mimic.

    In B. germanica, we found that myoglianin reduces juvenile hormone acid methyl transferase expression in the penultimate nymphal instar, which is a prerequisite for metamorphosis. Myoglianin is also involved in the production of the large ecdysone pulse needed to promote the metamorphic molt. Previous studies have shown that the factor FTZ-F1 induces the death of the prothoracic gland (PG) after the imaginal molt. But we have found that the action of FTZ-F1 is mediated by the adult specifier factor E93.

    In C. dipterum, we observed that metamorphosis occurs in the transition from last nymphal instar to subimago. In this transition, the expression of the antimetamorphic factor Kr-h1 decreases, and that of E93 increases. We also observed that juvenile hormone inhibits metamorphosis and induces the expression of Kr-h1.