A lectin of a non-invasive apple snail as an egg defense against predation alters the rat gut morphophysiology

ITUARTE, SANTIAGO; BROLA, TABATA ROMINA; FERNÁNDEZ, PATRICIA ELENA; MU, HUAWEI; QIU, JIAN-WEN; HERAS, HORACIO; DREON, MARCOS SEBASTIÁN

PLOS ONE

PUBLIC LIBRARY SCIENCE

Año: 2018 vol. 13

1932-6203

The eggs of the freshwater Pomacea apple snails develop above the water level, exposedto varied physical and biological stressors. Their high hatching success seems to be linkedto their proteins or perivitellins, which surround the developing embryo providing nutrients,sunscreens and varied defenses. The defensive mechanism has been unveiled in P. canaliculataand P. maculata eggs, where their major perivitellins are pigmented, non-digestibleand provide a warning coloration while another perivitellin acts as a toxin. In P. scalaris, aspecies sympatric to the former, the defense strategy seems different, since no toxin wasfound and the major perivitellin, PsSC, while also colored and non-digestible, is a carbohydrate-binding protein. In this study we examine the structure and function of PsSC bysequencing its subunits, characterizing its carbohydrate binding profile and evaluating itseffect on gut cells. Whereas cDNA sequencing and database search showed no lectindomain, glycan array carbohydrate binding profile revealed a strong specificity for glycosphingolipidsand ABO group antigens. Moreover, PsSC agglutinated bacteria in a dosedependentmanner. Inspired on the defensive properties of seed lectins we evaluated theeffects of PsSC on intestinal cells both in vitro (Caco-2 and IEC-6 cells) and in the gastrointestinaltract of rats. PsSC binds to Caco-2 cell membranes without reducing its viability,while a PsSC-containing diet temporarily induces large epithelium alterations and anincreased absorptive surface. Based on these results, we propose that PsSC is involved inembryo defenses by altering the gut morphophysiology of potential predators, a convergentrole to plant defensive lectins.