SPERMICIDAL ACTIVITIES OF StAPS (Solanum tuberosum ASPARTIC PROTEASES) INVOLVE MEMBRANE DAMAGE.

MENDIETA, JULIETA R., FALCINELLI, ANDREA L.; CESARI, ANDREíNA; PAGANO, MARIANA R.; DALEO, GUSTAVO R.; GUEVARA, MARíA G.

Rosario, santa Fe, Argentina

Congreso; Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006

We have previously reported the purification of two Potato Aspartic Proteases (StAP1 and StAP3) which have antimicrobial activity towards two potato pathogens, Fusarium solani and Phythophtora infestans by interaction with the microbial surfaces and  membrane permeabilization. Taking into account that spermicidal activity has been reported for other antimicrobial peptides, the aim of this study was to evaluate if StAPs exert this activity on bovine and human sperm. The effect of StAPs on sperm motility was studied in vitro by incubation of sperm suspensions with different doses of these proteins. The binding of StAPs on spermatozoa surface was monitored by incubation with FITC-labelled StAPs and membrane integrity was analyzed by SYTOX green uptake. Besides, the lysis effect of StAPs towards human erythrocytes was also evaluated. The results showed that StAPs reduced sperm motility in a dose-dependent manner, and 25 ìM StAPs completely abolished progressive motility. StAPs bind on postacrosomal and midpiece region of bovine sperm, and cause agglutination of spermatozoa. In vitro cell toxicity was observed by a dose-dependent increase in HOS negative sperm and SYTOX green uptake. However, no toxic effect was observed on erythrocytes. In conclusion, StAPs have spermicidal activity involving plasma membrane permeabilization by specific interaction with spermatozoa membrane