Uric acid within corpuscles presents in the perivascular tissue from the midgut gland of Pomacea canaliculata (Prosobranchia, Ampullariidae).

GIRAUD BILLOUD, MAXIMILIANO; VEGA, ISRAEL A; CARRIÓN, ADRIANA; GAMARRA-LUQUES, CARLOS; CASTRO-VAZQUEZ, ALFREDO

Mendoza

Congreso; XX Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2002

Sociedad de Biología de Cuyo

The midgut gland of P. canaliculata have a specialized perivascular tissue where some crystaloid corpuscles are found, the so called by us as G cps. Besides them columnar and pyramidal cells from the midgut gland acini bears two other distinctive corpuscles the C cps (pressumed vegetative) and the K cps (presumed kystic) forms of a putative symbiont that were said to have an excretory rol since the are both eliminated on the feces. We explore the possibility tha the snail uses the G cps as a disposal way of uric acid as an alternative excretion pathway. M&M: all cps were obtained by a benchtop metod developed in our lab as fractions C,K and G for each cps. Urea was quantified by Berthelot method (indofenol production in urease presence) and uric acid by uricase/peroxidase method (quinoneimins producton by oxidation). Reults: resulta are expressed as µg of each sustance form the cps per gland mass in grams. None of the fractions had urea. Uric acid levels were low but similar for C and K cps (1.67 ±0.26 mg/g ♀ and 2.11 ±0.34 mg/g ♂for C cps;: 1.74 ±0.42 mg/g ♀ y 4.12 ±1.84 mg/g ♂ for K) and higer for G cps (631.21 ±49.05 mg/g ♀ and 725.34 ±367.43 ♀). There were no significative sex differences in any case.(t test P ³0.05). Discusion: the presence of uric acid in G cps settles a possible physiological alternative for its excretion. As far as C and K cps show only traces of uric acid and absence of urea therefore questioning their possible rol in the nitrogen residues from the snail.