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To confirm whether Chinese mitten crabs (Eriocheir sinensis), commonly known as hairy crabs or river crabs, in non-Yangcheng Lake areas undergo morphological convergence with the original crabs in the Yangcheng Lake purse seine and high-standard modified aquaculture ponds after being "introduced" or "bathed"-cultured, we employed a geometric morphometrics approach. This approach allowed us to compare and analyze the dynamic changes in the carapace morphology of both the original and "introduced" crabs in Yangcheng Lake and high-standard ponds in Kunshan City at 0, 7, 14, and 30 days after "bathing" culture. The geometric morphological analysis of the carapace was conducted using a system of 35 established landmarks. The stepwise discriminant analysis of the relative distortion score revealed morphological differences between "introduced" and resident original crabs in the Yangcheng Lake area and in high-standard modified ponds after 7, 14, and 30 days of bathing culture. The accuracy of the discriminant analysis was 100%. The results of the geometric morphological visualization demonstrated that the carapaces of the bathed crabs underwent adaptive changes in the water. However, even after one month of bathing culture, the "introduced" crabs in lakes and ponds could not reach the morphological characteristics of the original crabs, i.e., their carapaces did not exhibit the characteristics of the original crabs. [ABSTRACT FROM AUTHOR]

Copper (Cu) contamination has become a severe problem in freshwater environments worldwide. The freshwater mussel Anodonta woodiana is used as a unique bioindicator to monitor Cu contamination in freshwater environments. However, Cu toxicity and response mechanisms in A. woodiana are still largely unknown. A sublethal acute exposure experiment (2.0 mg/L Cu exposure for 72 h) was conducted to investigate the effects of Cu bioaccumulation on ionoregulatory homeostasis, histological features, and transcriptome responses using A. woodiana gills as indicator tissue. The gill bioaccumulation capacity was up to 474. Cu bioaccumulation decreased Na+ and Mg2+ concentrations (p < 0.05) by 82% and 17%, respectively, and induced cilia loss, epithelial desquamation, and filament atrophy of the gills. Transcriptome analysis identified 3160 differentially expressed genes (DEGs), including 1870 upregulated and 1290 downregulated genes. GO enrichment analysis showed that cellular processes, metabolic processes, biological regulation, and responses to stimuli contained the most DEGs in the biological processes. KEGG pathway analysis showed that apoptosis, arginine and proline metabolism, the toll-like receptor signaling pathway, apoptosis-multiple species, histidine metabolism, beta-alanine metabolism, cytokine–cytokine receptor interaction, and the p53 signaling pathway were significantly enriched. These findings provide comprehensive evidence for exploring Cu toxicity and response mechanisms in freshwater mussels. [ABSTRACT FROM AUTHOR]

The levels of mineral element Na, Mg, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Mo, Al, As, Ag, Cd, and Tl were quantified in the whole shells of the freshwater bivalveAnodonta woodianaat three different growth stages (i.e. J1 juveniles of 1 month old, J2 juveniles of 3.5 months old, and adults of 36 months old). The concentrations of Na and Al were different between different growth stages (p < 0.05). The highest Na concentrations (2715 ± 86 μg/g dry weight) were found in J2 juveniles. The highest Al concentrations (303.9 ± 5.95 μg/g dry weight) were found in J1 juveniles. Manganese concentrations (517.0 ± 47.98 μg/g dry weight) were significantly higher in J2 juveniles than in J1 juveniles (432.3 ± 9.87 μg/g dry weight) (p < 0.05). Copper concentrations (27.32 ± 0.15 μg/g dry weight) were significantly higher in J1 juveniles than in J2 juveniles (26.21 ± 0.86 μg/g dry weight) and adults (24.74 ± 1.43 μg/g dry weight) (p < 0.05). Burdens of Na, Ca, Mn, Fe, Co, Cu, Mo, Ag, and Tl were positively correlated with the shell length (p < 0.05). These findings can possibly contribute to an understanding of elemental requirements for shell growth and, hence, facilitate improvement of survival and growth rates during artificial mussel culture. [ABSTRACT FROM AUTHOR]