Urate cells and tissues in the South American apple snail Pomacea canaliculata

GIRAUD-BILLOUD, M.G; KOCH, E.; VEGA, I.A.; GAMARRA-LUQUES, C.; ALFREDO JUAN CASTRO VAZQUEZ

JOURNAL OF MOLLUSCAN STUDIES

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2008 vol. 48 p. 259 - 266

0260-1230

Intracellular urate concretions are known to occur in some insects, crustaceans and gastropods. Crystalloid-containing urate cells and tissues were widespread in many organs of the South American apple-snail Pomacea canaliculata (Caenogastropoda, Ampullariidae). The occurrence of three different urate tissues (perivascular, compact and nodular ones) correlated well with uric acid concentrations found in the organs containing them. The highest uric acid concentrations were found in the coiled gut (showing both perivascular and compact tissues), the style sac (compact tissue), the testis, the midgut gland and the lung (perivascular tissue) and the aortic ampulla (nodular tissue). Lower concentrations were found in organs with perivascular tissue associated only to their main supplying vessels (anterior kidney and ctenidium), while organs devoid of urate tissues had minimal concentrations (mantle skirt, posterior kidney, albumen gland and heart). Transmission electron microscopy of urate cells was performed to disclose their morpho-functional characteristics, in view of their posible role as a readily available store of combined nitrogen. A process of sequential differentiation and death of urate cells, accompanied by the formation and resorption of urate crystalloids was found. This process occurred asynchronously in cells within the same tissue, suggesting an active turnover of uric acid in the organs containing them.