title: Potato aspartic proteases (StAPs) exert cytotoxic activity on bovine and human spermatozoa.
abstract: OBJECTIVE
  To evaluate the in vitro spermicidal activity of Solanum tuberosum aspartic proteinases (StAPs) on bovine and human sperm.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Three research laboratories at a university of biologic science. ANIMAL(S) AND DONOR(S): Frozen semen from five Aberdeen Angus bulls and six proven fertile men volunteers.
  
  
  METHODS
  The effect of StAPs on sperm motility was studied in vitro by incubation of different concentrations of StAPs with sperm suspensions, and motility was assessed by direct microscopic observation. Membrane integrity was analyzed by SYTOX Green uptake after incubation with different StAP concentrations. The effect of StAPs was evaluated by human erythrocyte lysis, as a control in somatic cells. The StAPs binding was monitored by fluorescence.
  
  
  METHODS
  Total and progressive sperm motility; hypoosmotic swelling test and SYTOX Green uptake as a measure of membrane damage; fluorescein isothiocyanate-labeled StAP binding by an optical microscopy.
  
  
  RESULTS
  The StAPs reduced sperm motility in a dose-dependent manner, and 25 microM of StAP1 and 35 microM of StAP3 completely abolished the progressive motility. The StAPs were able to bind in the postacrosomal and midpiece region only in bovine sperm. Also, StAPs caused spermatozoa agglutination. In vitro cell toxicity was observed by a dose-dependent increase in hypoosmotic swelling negative sperm and SYTOX Green uptake in both human and bovine spermatozoa; however, no toxic effect was observed on erythrocytes.
  
  
  CONCLUSIONS
  The spermicidal effect of StAPs involves plasma membrane permeabilization.
authors.affiliation: Laboratory of Biochemistry and Molecular Biology of Microorganism and Spermatozoa, Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Buenos Aires, Argentina. acesari@mdp.edu.ar
authors.forename: Andreina
authors.initials: A
authors.lastname: Cesari
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Falcinelli
authors.forename: Julieta R
authors.initials: JR
authors.lastname: Mendieta
authors.forename: Mariana R
authors.initials: MR
authors.lastname: Pagano
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mucci
authors.forename: Gustavo R
authors.initials: GR
authors.lastname: Daleo
authors.forename: María G
authors.initials: MG
authors.lastname: Guevara
mesh_terms: D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000302:isolation & purification / Q000633:toxicity*; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D003603:Cytotoxins / Q000302:isolation & purification / Q000633:toxicity*; D006801:Humans; D008297:Male; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology / Q000633:toxicity; D011198:Solanum tuberosum / Q000201:enzymology*; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology; D013089:Spermatocidal Agents / Q000302:isolation & purification / Q000633:toxicity; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology
chemical_list: D003603:Cytotoxins; D010936:Plant Extracts; D013089:Spermatocidal Agents; D016282:Aspartic Acid Endopeptidases