First insight into the major egg protein from the apple snail Pomacea insularum perivitellin fluid

PASQUEVICH, M.Y.; DREON, M.S.; HERAS, H.

Mendoza

Congreso; XLVIII Reunión SAIByBM; 2012

SAIByBM

Pomacea insularum, is a South American freshwater snail that is becoming a plague in Europe rice fields causing important economic loses and ecologic risk. Egg proteins (perivitellins) are important components of the perivitellin fluid that play several function during embryo development. Here we report the first data on the characterization of the major P. insularum perivitellin. Ultracentrifugation of egg cytosol in NaBr gradient showed three major protein peaks, the largest corresponds to a carotenoprotein complex hereafter named Pomacea insularum PV1 (PiPV1). This complex is responsible of the bright reddish color that characterizes the conspicuous egg masses. It is a lipoprotein with a hydration densitity of 1.25 g/mL that falls into the VHDL range. It is a 292 KDa oligomer composed of four subunits with masses between 25 and 35 KDa, been the oligomer held together by non-covalent forces. Here we report the biochemical features of PiPV1 and compare the particle with P. canaliculata and P. scalaris carotenoproteins, the only ones so far studied in molluscs. These proteins play important roles providing protection against factors such as sun radiation, egg desiccation, as well pathogens or predators. Further structural and functional analyses will expand our knowledge on embryo defensive proteins, giving an insight into the adaptive radiation of these invasive freshwater snails.