The Polypeptides/Proteins Exuded from Mimosa caesalpiniifolia Seeds Induce Ultrastructural and Biomechanical Modifications of the Caenorhabditis elegans Surface and Inhibit the Nematode Motility.

Abstract

Abstract Natural products have been studied as potential anthelmintic drugs. This study aimed to evaluate the effects of the polypeptides/proteins exuded from Mimosa caesalpiniifolia mature seeds on the model nematode Caenorhabditis elegans. After seed immersion for 24 h at 25 ºC in sodium phosphate buffer, pH 7.0, containing 0.15 M NaCl and 1.0 M MgSO4, the constituent polypeptides/proteins were fractionated using ammonium sulfate precipitation followed by ultrafiltration and their effects on C. elegans motility were assessed. Moreover, we evaluated by Atomic Force Microscopy (AFM) whether exposition of the nematode to the polypeptide fraction McSEX10-2 could cause any alteration on the animal’s external surface (cuticle). The whole seed exudates (SEX) from the M. caesalpiniifolia mature seeds (named McSEX) and its polypeptide/protein derived fractions, termed McSEX90%/80°C, McSEX30-10, and McSEX10-2, inhibited the C. elegans motility with an IC50 of 15.18, 12.59, 9.74 and 1.34 μg mL-1.The McSEX10-2 fraction, which encompassed the polypeptides with the molecular mass varying from 10 kDa to 2 kDa, was the most effective. In addition, McSEX10-2 altered the ultrastructure and the mechanical properties of the C. elegans cuticle. McSEX10-2, in particular, can be used as a model to bioinspire structure-based design of new peptides that could control, alone or in combination with other drugs, economically important parasitic nematodes.

Keywords

• Mimosa caesalpiniifolia
• seed exudation
• anthelmintic protein/peptides
• Caenorhabditis elegans
• nematodes