INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The Role of the Proteinase Inhibitor Ovorubin in the Apple Snail Eggs Defenses Against Predation
Autor/es:
DREON, M.S.; ITUARTE,S.; FRASSA,V.; HERAS, H.
Lugar:
Tucumán
Reunión:
Workshop; IV International workshop on the biology of Ampullariidae; 2010
Institución organizadora:
CONSEJO NAC.DE INVEST.CIENTIF.Y TECNICAS / CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA / INST.DE INVEST.BIOQUIMICAS DE LA PLATA
Resumen:
. Many serine proteinase inhibitors have been identified from egg-laying organisms such as arthropods, birds, and reptiles and invariably a role in resistance to pathogens has been ascribed to them. The aerial egg clutches of the aquatic snail Pomacea canaliculata have virtually no predators and the nature of the defense was unclear, except for a previous report from our group on a neurotoxic perivitellin with lethal effect on mice. Ovorubin, the major egg protein of this snail, is a proteinase inhibitor (PI) whose role to protect against pathogens was taken for granted, according to the prevailing assumption. Employing different biochemical and biophysical techniques together with feeding experiments we studied the role of ovorubin in egg defenses. Mass spectrometry sequencing indicated ovorubin belongs to the small Kunitz-type serine proteinase inhibitor family. It specifically binds trypsin as determined by small angle X-ray scattering (SAXS) and cross-linking studies but, in contrast to the classical assumption, neither ovorubin nor other egg components prevents bacterial growth. Ovorubin was resistant to in vitro gastrointestinal proteolysis retaining its antitryptic activity. Moreover feeding studies showed that ovorubin ingestion diminishes growth rate in Wistar rats indicating that this PI survey the passage through the gastrointestinal tract in an active form. This is the first direct evidence of the interaction of an egg PI with a digestive protease of potential predators, limiting predator’s ability to digest egg nutrients. This role has not been reported in the animal kingdom but it is similar to plant defenses against herbivory.