Meeting Abstract
A fundamental question in biology is how do organisms sense and assess tissue development in proportion to the growth of the whole body. Growth delay during metamorphosis, the “puberty” phase in insects, is observed in a number of holometabolous insects when there is local damage to regenerative tissue such as the imaginal discs. An unexpected benefit of the delay is a period for damaged cells to regenerate and minimize disruptions in body allometry. This project attempts to characterize the mechanism of communication between damaged imaginal discs and the endocrine center in the hornworm, Manduca sexta. It is hypothesized that the hemolymph (blood) carries secreted factor(s) to the endocrine centers and delays production or release of developmental hormones required to initiate adult eclosion. In this study, we used SDS-PAGE and western blot to measure changes in (i) developmental hormones via phosphorylation of the downstream ERK/RSK signaling cascade, and (ii) protein abundance in hemolymph of the damaged larvae, including insulin-like proteins previously identified as the delay factor secreted in Drosophila melanogaster. This data should ascertain in M. sexta which signals are released from damaged imaginal discs, and that target endocrine systems to delay development. Identifying the developmental delay mechanism in M. sexta will provide further insight for how organisms adapt to disturbances in tissue development and may help us understand similar puberty delays in human inflammatory diseases. It may also provide a new model system for addressing the interactions of insulin-like-peptide and developmental hormones in growth and development in insects.
