EXTRACELULAR DIGESTION OF PROTEINS ALONG THE INTESTINE OF THE APPLE SNAIL Pomacea canaliculata

GODOY M.; VEGA I.

San Juan

Congreso; 2da. Reunión conjunta de Sociedades de Biología de la República Argentina, XXIX Reunión Anual de la Sociedad de Biología de Cuyo; 2011

The digestive physiology of this snail was revisited because it was previously reported the absence of protease activity in the intestinal content of ampullariids and the endosymbiont isolated from the midgut gland (MGG) had an important intrinsic protease activity. Specific protease activity (mIU/mg of protein) changed along the intestine of P. canaliculata. It was significantly higher in the coiled gut content than in the crop and stomach contents (ANOVA, p<0.05). Zymography of these contents showed proteases of 32 and 130 kDa in the crop and stomach and 32, 150 and 200 kDa in the coiled gut. Aprotinin (serín-protease inhibitor) inhibited the 60% of protease activity in crop and stomach contents. This inhibition was positive in all soluble proteases found (30, 130 and 150 kDa). The optimal temperature and pH for protease activity were 30-35ºC in all content studied (crop, stomach and coiled gut) and pH 8.5 in stomach contents and pH 9.5 in crop and coiled gut contents, respectively. Leu-N-aminopeptidase specific activity was gradually increased from the crop to the coiled gut, with the significantly higher specific activity in the MGG (ANOVA, p<0.05). We suggested that this snail can carried out protein digestion using soluble and membrane associated proteases (leu-N-aminopeptidases).