Implications of an endosymbiont in digestive physiology of Pomacea canaliculata (Caenogastropoda, Ampullariidae)

GODOY M.S.; VEGA I.A.

Potrero de Los Funes, San Luis

Congreso; XXX Reunión Anual de la Sociedad de Biología de Cuyo; 2012

Pigmented C and K corpuscles are morphs of an endosymbiont akin to the Cyanobacteria that lives and reproduces within the digestive gland cells of P. canaliculata and it is later expelled in the feces. In previous studies we found an ubiquitous serine-protease of 30 kDa in the intestinal lumen of this snail, which it is stored/secreted by the digestive gland. The aim of this work was to test the hypothesis that these symbionts can digest the proteins ingested in the diet. Gel zymography showed a 30 kDa protease in both morphological types of the endosymbiont which corresponds to that found in the gastric contents and digestive gland extracts. Furthermore, a study of in situ zymography using DQ-gelatin as substrate showed the total protease activity is located in the basal zone of the alveoli of the digestive gland, as well as in its endosymbionts. This activity was inhibited in presence of serine-protease inhibitor aprotinin, and not with non-serine-protease inhibitors. Together, our results suggest that the glandular protease of 30 kDa is originated in the endosymbiotns and that they help to digest enzymatically the dietary proteins.