Intensive industrial activities nowadays are accelerating the releases of trace metals from various sources, posing potential threats to living organisms. Notably, extremely high levels of metals have been observed in oysters from metal contaminated estuaries, e.g., up to 1.9% Cu and 2.4% Zn in dried tissues. However, the molecular basis underlying such high metal levels remains obscure. Therefore, we employed the emerging transcriptomics and proteomics to investigate the biological effects of metal exposures on an estuarine oyster Crassostrea hongkongensis. The levels of accumulated metals in oysters would alter the expressional profiles and further lead to phenotypic differentiation. Comparatively, more critical alterations were observed in oysters with a higher metal body burden. The...[ Read more ]

Intensive industrial activities nowadays are accelerating the releases of trace metals from various sources, posing potential threats to living organisms. Notably, extremely high levels of metals have been observed in oysters from metal contaminated estuaries, e.g., up to 1.9% Cu and 2.4% Zn in dried tissues. However, the molecular basis underlying such high metal levels remains obscure. Therefore, we employed the emerging transcriptomics and proteomics to investigate the biological effects of metal exposures on an estuarine oyster Crassostrea hongkongensis. The levels of accumulated metals in oysters would alter the expressional profiles and further lead to phenotypic differentiation. Comparatively, more critical alterations were observed in oysters with a higher metal body burden. The disruption of structural components (e.g., cytoskeleton and membrane) was identified as the potential biomarkers for the highly contaminated oysters. Reactive oxygen species (ROS) might be the primary toxicity under the extremely high levels of Cu and Zn, thus resulting in protein damages. The higher Cd content might induce genotoxicity in oysters. Nonetheless, oysters also possessed strategies to alleviate the damages resulting from metals and survive in the contaminated environments, including protein synthesis, removal of misfolded protein, and ROS clearance. Moreover, the role of Cu on oysters was systematically investigated based on the novel pattern of Cu content during larval development, displaying a sharp increase at the late pelagic stage. With the help of transcriptomics, the role of Cu on larval development was uncovered, including its participation in the shell formation and settlement. Further in-depth investigations on the unique differentiation of metals at the individual and tissue levels are needed to improve the understanding of metals in oysters.