| Diapause is an alternate state of development usually programmed by short photoperiod, low temperatures and reduced food quality, all cues predicting the advent of deteriorating environmental conditions. This dormancy, called diapause, is usually characterized by a halt in development, reduced metabolism, decrease in oxygen consumption, cell cycle arrest and an increase in defense, immune and cryoprotective molecules. Regulation of diapause is species specific and controlled by complex interactions between gene expression, protein production and neuro-endocrine regulation. Within this dissertation we examined the pupal diapause of two insect species, the flesh fly Sarcophaga crassipalpis and the tobacco hornworm Manduca sexta. Although the physiological and neuro-endocrine aspects of flesh fly diapause are well-documented the molecular and especially the proteomic regulation of diapause in this species is less well defined. In this body of work we further characterize the cell cycle arrest observed in the cells of the brain during the pupal diapause of the flesh fly. We show that genes associated with the G1 to S phase progression are down-regulated during diapause. We also performed a proteomic comparison between non-diapausing and diapausing flesh flies. We identified a total of 27 proteins that are produced in different levels between the two conditions (non-diapause and diapause), and have categorized these proteins based on their biological functions. A proteomic comparison has also been performed on hemolymph of non-diapausing and diapausing M. sexta. In this species we identified 13 proteins that are differentially produced between the diapause and non-diapause conditions. Following identification, production of these proteins was characterized at various diapause time-points through diapause day 48. |
