Genomic Platforms and Molecular Physiology of Insect Stress Tolerance.

摘要

As ectotherms with high surface area to volume ratio, insects are particularly susceptible to desiccation and low temperature stress. In this dissertation, I examine the molecular underpinnings of two facets of these stresses: rapid cold hardening and cryoprotective dehydration.;Rapid cold hardening (RCH) is an insect's ability to prepare for cold stress when that stress is preceded by an intermediate temperature for minutes to hours. In order to gain a better understanding of cold shock, recovery from cold shock, and RCH in Sarcophaga bullata I examine the transcriptome with microarray and the metabolome with gas chromatography coupled with mass spectrometry (GCMS) in response to these treatments. I found that RCH has very little effect on the transcriptome, but results in a shift from aerobic metabolism to glycolysis/gluconeogenesis during RCH and preserved metabolic homeostasis during recovery.;In cryoprotective dehydration (CD), a moisture gradient is established between external ice and the moisture in the body of an insect. As temperatures decline, the external ice crystals grow, drawing in more moisture which dehydrates the insect causing its melting point to track the ambient temperature. To gain a better understanding of CD and dehydration in Belgica antarctica I explore the transcriptome with RNA sequencing and the metabolome with GCMS. I found an up regulation of genes involved in autophagy and down regulation of those involved in apoptosis. I also found coordinated shut down of metabolism during cryoprotective dehydration.;Sequencing the genome of an organism is an expensive and time consuming endeavor, but with the advent of next generation sequencing, it is possible for a single lab or a small group of allied labs to undertake the task. Because of its importance as a model for polar biology, low temperature biology, and dehydration tolerance, I present the assembled, annotated, and characterized genome of B. antarctica. Because of its importance as a model for diapause and low temperature biology, I present the assembled, annotated, and characterized genome of S. bullata.