Snail egg toxin effects on gut. A possible antipredation defense mechanism

GIGLIO, MATÍAS L.; HERAS, HORACIO

Nelson

Congreso; Physiomar 2021; 2021

Conferences & Events Ltd

Apple snails from the Pomacea genus are freshwater amphibious snails characterized by aerial oviposition, an unusual reproductive strategy that exposes the eggs to harsh conditions and terrestrial predators. However, these eggs are ignored by most cohabitant fauna, which is explained by the presence of a complex defense system including aposematic coloration and a suite of defensive proteins currently under research. Among these, Pomacea snail eggs have evolved clade-specific toxic lectins. One such lectin is the perivitellin-2 (PV2) a pore-forming AB toxin that combines a lectin attached to a membrane attack protein from the MACPF family. This extends the presence of bacteria and plant AB-toxins to animals. Moreover, it is the first animal enterotoxin. It withstands gastrointestinal environment, including pH and enzymatic proteolysis. PV2 promotes morphological changes in intestinal cells and induced cell death by a lytic mechanism. Further, after oral administration to mice PmPV2 attached to enterocytes and induced large morphological changes on their small intestine mucosa, reducing the absorptive surface. We also observedmembrane cholesterol levels strongly affect both, PV2 affinity and PV2 capacity to form pores triggering toxicity in a dose-dependent manner. These defensive toxins may contribute to apple snail egg protection against predators.