The ectoperitrophic space (EcPS) between the insectmidgut epithelial cells and the peritrophic matrix isan unexplored, clean resource for concentrated pro-teins secreted by the midgut epithelial cells, whichoffers an ideal opportunity to uncover the midgutfunctions. In this study, we usedBombyx morias amodel organism and performed comparative proteo-mic analyses of the secreted proteins in the EcPS atthe feeding and wandering stages. A total of 372 pro-teins were identified from both stages and 70 proteinswere predicted to be secreted. Amongst these pro-teins, 17 secreted digestive proteins were identifiedand their temporal and spatial transcriptional expres-sion patterns demons... More
The ectoperitrophic space (EcPS) between the insectmidgut epithelial cells and the peritrophic matrix isan unexplored, clean resource for concentrated pro-teins secreted by the midgut epithelial cells, whichoffers an ideal opportunity to uncover the midgutfunctions. In this study, we usedBombyx morias amodel organism and performed comparative proteo-mic analyses of the secreted proteins in the EcPS atthe feeding and wandering stages. A total of 372 pro-teins were identified from both stages and 70 proteinswere predicted to be secreted. Amongst these pro-teins, 17 secreted digestive proteins were identifiedand their temporal and spatial transcriptional expres-sion patterns demonstrated that all these proteinswere up-regulated at the feeding stage and differen-tially expressed in different parts of the midgut. Pro-teins with nutrient reservoir activity and defenceactivity were found to be up-regulated at the wander-ing stage. This work is the first to show the presenceof digestive enzymes in the EcPS of the insect midgutusing a proteomic approach, which provides evi-dence that suggests a physiological functional differ-entiation of the insect midgut. It is very clear that theEcPS undergoes dynamic changes in its compositionof proteins in response to the changing needs of theinsect at different developmental stages
