Functional Analysis of Insect Molting Fluid Proteins on the Protection and Regulation of Ecdysis
Year: 2014
Type: article
Abstract: Molting fluid accumulates between the old and new cuticles during periodical ecdysis in Ecdysozoa. Natural defects in insect ecdysis are frequently associated with melanization (an immunity response) occurring primarily in molting fluids, suggesting that molting fluid may impact immunity as well as affect ecdysis. To address this hypothesis, proteomic analysis of molting fluids from Bombyx mori during three different types of ecdysis was performed. Many proteins were newly identified, including immunity-related proteins, in each molting fluid. Molting fluids inhibited the growth of bacteria in vitro . The entomopathogenic fungi Beauveria bassiana , which can escape immune responses in feeding larvae, is quickly recognized by larvae during ecdysis, followed by melanization in molting fluid and old cuticle. Fungal conidia germination was delayed, and no hyphae were detected in the hemocoels of pharate instar insects. Molting fluids protect the delicate pharate instar insects with extremely thin cuticles against microorganisms. To explore the function of molting fluids in ecdysis regulation, based on protein similarity, 32 genes were selected for analysis in ecdysis regulation through RNAi in Tribolium castaneum , a model commonly used to study integument development because RNAi is difficult to achieve in B. mori . We identified 24 molting proteins that affected ecdysis after knockdown, with different physiological functions, including old cuticle protein recycling, molting fluid pressure balance, detoxification, and signal detection and transfer of molting fluids. We report that insects secrete molting fluid for protection and regulation of ecdysis, which indicates a way to develop new pesticides through interrupting insect ecdysis in the future.Periodical ecdysis occurs in insects with molting fluids accumulated among the old and new cuticles. Results Molting fluid is a mixture containing many unknown proteins to inhibit microbian infection and regulate ecdysis. Conclusion Insects produce molting fluids for protecting delicate insects and guaranteeing successful ecdysis. Significance Molting proteins may be targets useful for pesticide development in the future.
Source: Journal of Biological Chemistry
Authors: Jie Zhang, Anrui Lu, Lulu Kong, Qiaoli Zhang, Erjun Ling
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W2007176250