Histological responses to sublethal concentrations of copper in the digestive gland of Pomacea canaliculata Lamarck (Gastropoda: ampullariidae)
1999
Co, E.L.
Adult specimen of Pomacea canaliculata Lamarck were exposed to sublethal concentrations (0.32, 0.36, 0.40, 0.45, and 0.50 ppm) of copper for 96-hour period. Histopathological changes in the digestive glands were analyzed and the copper concentrations were determined using atomic absorption spectroscopy. Results revealed that copper ions induced the appearance of dense bodies and promoted the disorganization of the digestive epithelia and dilation of the lumen of the digestive tubules. The most common ultrastructural changes include the appearance of phagosomes, swelling of the mitochondria and rough endoplasmic reticulum [ER] widening or loss of mitochondrial cristae, degranulation of rough ER membranes and whorl formation. These aberrations were observed in both the digestive and calcium cells at higher copper concentrations from 0.40 to 0.50 ppm. Large and giant-sized (4 to 6 micro m in diameter) mitochondria, however, were noted only in the calcium cells. These cellular reactions can be correlated with the high copper content in the digestive gland of Pomacea and this coincided with the rise in the mean number of calcium cells. Detoxification of copper may have involved the spherules of calcium cells which are capable of storing copper ions in an insoluble form and its extrusion into the lumen of the digestive gland
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