Integrated transcriptomic and metabolomic analysis sheds new light on adaptation of Pinctada fucata martensii to short-term hypoxic stress.

Analyses of the transcriptome and metabolome were conducted to clarify alterations of key genes and metabolites in pearl oysters following exposure to short-term hypoxic treatment. We totally detected 209 DEGs between the control and hypoxia groups. Enrichment analysis indicated the enrichment of GO terms including "oxidation-reduction process", "ECM organization", "chaperone cofactor-dependent protein refolding", and "ECM-receptor interaction" KEGG pathway by the DEGs. In addition, between the two groups, a total of 28 SDMs were identified, which were implicated in 13 metabolic pathways, such as "phenylalanine metabolism", "D-amino acid metabolism", and "aminoacyl-tRNA biosynthesis". Results suggest that pearl oysters are exposed to oxidative stress and apoptosis under short-term hypoxia. Also, pearl oysters might adapt to short-term hypoxic treatment by increasing antioxidant activity, modulating immune and biomineralization activities, maintaining protein homeostasis, and reorganizing the cytoskeleton. The results of our study help unveil the mechanisms by which pearl oysters respond adaptively to short-term hypoxia.

Low-Cost Ni2P/Ni0.96S Heterostructured Bifunctional Electrocatalyst toward Highly Efficient Overall Urea-Water Electrolysis.

Water splitting is a sustainable approach for production of hydrogen to fuel some clean energy technologies. This process, unfortunately, has been significantly impeded by the puzzles in either the efficient but economically unaffordable noble-metal-based catalysts or the low-cost but kinetically sluggish abundant-element-based catalysts. Particularly, the discovery of efficient bifunctional catalysts that can simultaneously trigger the reactions of both anode and cathode for overall water splitting still remains as a grand challenge. Herein, a novel low-cost bifunctional Ni2P/Ni0.96S heterostructured electrocatalyst, which is active for both the urea oxidation reaction at the anode and the hydrogen evolution reaction at the cathode, is innovated for high-efficiency overall splitting of urea-rich wastewater. A systematic configuration of a Ni foam (NF)-supported Ni2P/Ni0.96S catalyst electrode exhibits superior catalytic activity and stability. The Ni2P/Ni0.96S/NF||Ni2P/Ni0.96S/NF cell needs only 1.453 V to reach a current density of 100 mA/cm2 in basic urea-containing water, while it is 1.693 V for a reference noble-based Pt/C/NF||IrO2/NF electrolysis cell. This work therefore not only contributes to develop a low-cost, high-efficiency, bifunctional electrocatalyst but also provides a practically feasible approach for urea-rich wastewater treatment.