Profiling the peptidomic and structural-functional characterization of lipid vesicles present in the Nephila clavipes web spider

Abstract

Nephila clavipes spider belongs to the group of orb-weaving spiders that have developed the ability to synthesize adhesive threads. These adhesive threads are found in the web capture spiral, and contain oil droplets containing extracellular lipid vesicles that trap in their interior solutions of proteins, peptides and low molecular mass compounds. Among these molecules many are protein and low molecular mass compounds toxins, which may have potent lethal actions (insecticides) for the captured prey. Therefore, the presence of these molecules demonstrates that the web can play a strategic "active-chemical" role in capturing its prey. At the moment, little is known about the peptide composition of this web; considering this, one of the objectives of this study will be to explore the richness of silk-web peptides and of the silk-producing glands N. clavipes spider by LC-MS/MS approaches, highlighting the possible toxins involved in paralysis and death of prey. Besides that, the present study also aims to perform the chemical characterization of the lipid vesicles present in the webs, in order to try to reproduce in the laboratory these elaborate biological structures, whose purpose is to carry compounds of insecticidal action into the bodies of their prey. For these reasons the present project also provides for the realization of a series of insect-toxicity assays, with the extracellular lipid vesicles containing different phospholipid compositions. Thus, this study will provide a better chemical-ecological understanding of prey capture by the N. clavipes spider web, besides being an inspiration for the development of new insecticide-selective strategies, or even for possible pharmacological applications. (AU)