Effect of waterborne copper on the microstructures and ultrastructure of the X-organ sinus gland complex in Eriocheir sinensis

The effects of different water-borne copper (Cu ²⁺) concentrations on the microstructures and ultrastructures of the X-Organ sinus gland (XO/SG) in Eriocheir sinensis were studied. Under a light microscope, no significant differences were found between the treated and control groups. Under Transmission Electron Microscopy (TEM), the mitochondrial cristae in the neuro-terminal of the XO of the 5.00 mg/L Cu ²⁺ treated group disappeared, or even only a few vacuoles left. No other differences were found in SG between the 0.01, 0.10, and 1.00 mg/L Cu ²⁺ treated and the control group under light microscopy, except for the 5.00 mg/L Cu ²⁺ treated groups, in which the boundary between the SG hemocoels and glial cells became unclear, and some central hemocoels closed and even disintegrated. In addition, in the 5.00 mg/L Cu ²⁺ treated groups the hemocytes mixed with the glial cells, axon terminal disordered arranged, and furthermore, under the TEM glial cells ruptured, mitochondrial cristae disappeared, or even remained only a vacuoles. Such a change also occurred in the mitochondria in the axon terminal. In some of the glial cells the structure of the membrane disintegrated, the cytoplasm disappeared, and the nucleus entered the haemocoels being piled together with the hemocytes. The axon terminal and neurosecretory granular decreased near the amorphous figurationling of the haemolymph. The results indicate that the damage to the microstructure and ultrastructure of the XO/SG was relevant to the elevated water-borne copper concentration in E. sinensis.