Juvenile hormone biosynthesis in the cockroach, Diploptera punctata: the characterization of the biosynthetic pathway and the regulatory roles of allatostatins and NMDA receptor

The juvenile hormones (JH) play essential roles in regulating growth, development, metamorphosis, ageing, caste differentiation and reproduction in insects. Diploptera punctata, the only truly viviparous cockroach is a well-known model system in the study of JH biosynthesis and its regulation. The physiology of this animal is characterized by very stable and high rates of JH biosynthesis and precise and predictable reproductive events that correlate well with rates of JH production. Many studies have been performed on D. punctata to determine the function of JH. However, the pathway of JH biosynthesis has not been identified. In addition, although many factors are known to regulate JH biosynthesis, the exact mechanisms remain unclear. The aim of my research was to elucidate the JH biosynthetic pathway in D. punctata and study the mechanisms by which allatostatin (AST) and N-methyl-D-aspartate (NMDA) receptor regulate JH production. I have (1) identified genes in the JH biosynthetic pathway, and determined their roles in JH biosynthesis; (2) investigated the mode of action of AST by determining the signaling pathway of AstR and the target of AST action; (3) determined the role of the NMDA receptor in JH biosynthesis using RNA interference and treatment with an NMDA receptor antagonist. To validate the application value of my research, AST analogs with high JH inhibitory activity were designed and their activities on JH biosynthesis were measured by in vitro and in vivo bioassays.