Action of Lytic Peptides Based on a Salivary Protein From Triatoma Infestans on Acanthamoeba Castellanii

Abstract

Purpose: : Trialysin is a pore–forming lytic protein from the saliva of the insect Triatoma infestans, active against Trypanosoma cruzy. In this study we evaluated the ability of a synthetic lytic peptide corresponding to the lytic portion of trialysin against culture–derived Acanthamoeba castellanii trophozoites

Methods: : Axenic strains of Acanthamoeba castellanii (ATCC30011) were maintained in Neff medium at 25°C in 25 cm² culture flasks. Trophozoites were obtained by mechanically releasing adhered cells from culture flasks in new medium. The synthetic peptide P6 resuspended in water was incubated in the desired concentrations with the same volume of about 1 x 10⁶ trophozoites/ml for 1 hour at 25°C. Chlorhexidine was used as a positive control.Viability was determined by trypan–blue dye exclusion test and the number of viable cells was determined in a Neubauer hemacytometer. Percentage of viable cells was determined according to the controls, performed in the absence of the drugs.

Results: : Preliminary assays using peptide have demostrated its activity on A. castellanii cells. The cell mortality rate was 32% at concentration of 117µg/ml and 88% at 294 µg/ml. Total lysis was seen at concentration of 441 µg/ml.

Conclusions: : Our data indicate that P6 was effective against Acanthamoeba castellanii trophozoites. Best characterization of lysis is being performed as well as other lytic peptides based on trialysin are being tested in order to determine the best lytic peptide. These results can be important in the development of new anti–Acanthamoeba compounds.

Keywords: amoeba • antibiotics/antifungals/antiparasitics • pharmacology