Transcriptomic, proteomic and structural analyses of Drosophila melanogaster larval midgut

The insect midgut is a dynamic tissue involved in enzyme production, food digestion, and nutrient absorption. It is also a highly important interface between the insect and its environment. The following thesis focuses on the midgut of the third-instar Drosophila melanogaster larva. It describes the genes associated with the tissue and explores the responses of this tissue to the challenge of a dietary Bowman-Birk Inhibitor (BBI), a plant-produced natively-occurring protease inhibitor. Serine proteases were found to be the main proteolytic enzymes. Some 40% of cytochrome P450 genes and 72% of glutathione S transferases known to be included in the genome of Drosophila were observed to be expressed in the midgut. Protease inhibitors (PIs) have negative effects on the growth and development of insect pests and have been considered as potential candidates for insect management. My thesis focused on the molecular interactions and responses of genes and proteins of the Drosophila larval midgut to BBI at transcriptomic, proteomic levels, and observations of physical structural changes of the midgut using light and transmission electronic microscopy. Using bioinformatic analyses, I identified potential transcription factor-binding motifs of genes that are differentially expressed in response to the challenge of dietary BBI