Copper Stress Causes Shell Morphology Changes in Early Juvenile Anodonta woodiana Based on Geometric-Morphometric Analysis.

In this study, the morphological characteristics of early juvenile shells of Anodonta woodiana, which were exposed to different concentrations of aqueous copper, were analyzed using 10 landmarks to determine morphological changes in the shells. Morphological changes mainly occurred at the top of the shell and front and back ends of the central axis. Stepwise discriminant analysis proved shape differences among experimental and control groups. The results of this study demonstrate for the first time that environmentally relevant copper concentrations cause stress-related morphological changes in A. woodiana in the vulnerable early juvenile stage.

Reconstruction of Historical Metal Backgrounds in Lacustrine Environments of China Using an Anodonta woodiana "Specimen Bank".

Anodonta woodiana samples from Xidong Water Works and Mashan in Taihu Lake, Yiyang near Dongting Lake, and Taiping Harbor in Gehu Lake preserved in a "specimen bank" established for the "Freshwater Mussel Watch" monitoring program were used to determine the historical metal backgrounds from different waters in the present study. The elements Co, Ni, Mo, Cd, Al, Cr, Mn, Fe, Cu, Zn, As, Ba, and Pb were determined using A. woodiana from four lacustrine sites. The results showed that Al, Cr, Mn, Fe, Cu, Zn, As, Ba, and Pb were all detected, whereas Co, Ni, Mo, and Cd were below the detection limits of 0.0165, 0.0106, 0.0189 and 0.0182 µg kg- 1, respectively. In particular, A. woodiana was noted to be an unusual Mn hyperaccumulator (ranged from 5124.09 to 13015.47 µg g- 1). The results of discriminant analysis showed that the four water samples could be accurately separated. This difference has the potential to infer the background difference of heavy metal pollution in different lacustrine habitats.

Copper induces cytotoxicity in freshwater bivalve Anodonta woodiana hemocytes.

Hemocytes of freshwater bivalves are an important target model for evaluating copper (Cu) toxicity in vitro, with excess Cu causing adverse responses in these organisms. Despite this, the mechanisms underlying cytotoxicity remain poorly understood. The freshwater bivalve Anodonta woodiana, employed as a model organism in freshwater environments, was utilized in this study. Hemocytes of A. woodiana were exposed to various aqueous Cu treatments (0.001, 0.01, 0.1, 1, and 10 mg/L), and a control group (no Cu added) for 3 h to investigate the cytotoxic mechanisms of Cu. The results showed a significant increase in the production of reactive oxygen species in hemocytes of all Cu exposed groups compared to the control (p < 0.05). Remarkably, Cu treatments disrupted the cellular membrane (p < 0.05) but did not induce significant changes in the stability of the lysosomal membrane. Cu targeted the mitochondria, leading to a reduction in mitochondrial membrane potential. Additionally, all Cu treatments significantly increased the degree of DNA damage (p < 0.05). Cellular damage and a significant decline in cell viability were observed when the Cu exposure concentration reached 0.1, 1, and 10 mg/L (p < 0.05). Our study provides new insights into the cytotoxicity mechanisms triggered by Cu in hemocytes of the freshwater bivalve A. woodiana, even under environmentally relevant conditions of 0.01 mg/L exposure.

Multi-mineral fingerprinting analysis of the Chinese mitten crab (Eriocheir sinensis) in Yangcheng Lake during the year-round culture period.

Chinese mitten crabs (Eriocheir sinensis), originating from Yangcheng Lake, are valuable aquatic products in China. To characterize changes in nutrients in this species in Yangcheng Lake during the year-round culture period, the contents of ten mineral elements in the third pereiopod were evaluated. Principal component analysis revealed that mineral elements changed substantially in the first three months. Thereafter, the elemental "fingerprint" stabilized, and samples could not be accurately distinguished. This pattern was supported by linear discriminant analysis and self-organizing map analysis. These results demonstrate that a long period of time is required for element characteristics to stabilize, suggesting that short-term breeding is insufficient to obtain the natural elemental "fingerprint." In addition, our findings provide a basis for verifying the origin of Chinese mitten crab and other aquatic taxa in Yangcheng Lake.