Tunable Toxicity of Bufadienolides is Regulated through a Configuration Inversion Catalyzed by a Short-Chain Dehydrogenase/Reductase.

Bufadienolides are toxic components widely found in amphibious toads that exhibit a wide range of biological activities. Guided by UPLC-QTOF-MS analysis, several 3-epi-bufadienolides with unique structures were isolated from the bile of the Asiatic toad, Bufo gargarizans. However, the enzymatic machinery of this epimerization in toads and its significance in chemical ecology remains poorly understood. Herein, we firstly compared the toxicities of two typical bufadienolides, bufalin (featuring a 14ß-hydroxyl) and resibufogenin (containing a 14, 15-epoxy group), with their corresponding 3-epi isomers in a zebrafish model. The results of the toxicology assays showed that the ratio of maximum non-toxic concentrations of these two pairs of compounds are 256 and 96 times, respectively, thereby indicating that 3-hydroxyl epimerization leads to a significant decrease in toxicity. Aiming to investigate the biotransformation of 3-epi bufadienolides in toads, we applied liver lysate to transform bufalin and found that it could stereoselectively catalyze the conversion of bufalin into its 3α-hydroxyl epimer. Following this, we cloned and characterized a short-chain dehydrogenase/reductase, HSE-1, from the toad liver cDNA library and verified its 3(ß→α)-hydroxysteroid epimerization activity. To the best of our knowledge, this is the first hydroxyl epimerase identified from amphibians that regulates the toxicity of animal-derived natural products.

Towards High-Performance Supercapacitor Electrodes via Achieving 3D Cross-Network and Favorable Surface Chemistry.

Transition metal phosphides/phosphates (TMPs) are considered appealing electrode materials in energy-related fields, especially in supercapacitors. However, the dilemma of inadequate electrode kinetics and dimensional unreliability evoked by a huge volume variation during cycling significantly plagues their progress. To mitigate this issue, in this work, a 3D cross-network in situ assembled via self-derived N-doped carbon hybrid Ni-Co-P/POx 2D sheets is fabricated. Particularly, high-Fermi-level N-doped carbon well confines Ni-Co-P/POx nanoparticles at the molecular level, and N-doping leads to redistribution of spin/electron density in the carbon skeleton, effectively regulating the electron environment of nearby Ni-Co-based moieties, resulting in a relatively lower surface work function, as known via experimental and Kelvin probe force microscopy (KPFM) results, which favors electron flee from the electrode surface and facilitates electron transport toward a rapid supercapacitor response. Moreover, the well-defined 3D cross-network architectures featured with in-plane pores and interconnected with each other can provide more ion/electron transfer pathways and 2D sheets with excellent surface chemistry available for sustainable ion/electron mobility, synergistically affording the favorable electrode kinetics. Accordingly, the resultant Ni-Co-P/POx@NC electrode shows admirable specific capacitance, excellent rate survivability, and long-term cyclability. The as-assembled asymmetric device exhibits remarkable energy and power outputs (48.5 Wh kg-1 and 7500 W kg-1), superior to many reported devices. Furthermore, our devices possess the prominent ability to power a commercial electronic thermometer for 1560 s at least, showcasing superb application prospects.

Does the Credit Cycle Have an Impact on Happiness?

The 2008 international financial crisis triggered a heated discussion of the relationship between public health and the economic environment. We test the relationship between the credit cycle and happiness using the fixed effects model and explore the transmission channels between them by adding the moderating effect. The results show the following empirical regularities. First, the credit cycle has a negative correlation with happiness. This means that credit growth will reduce the overall happiness score in a country/region. Second, the transmission channels between the credit cycle and happiness are different during credit expansion and recession. Life expectancy and generosity can moderate the relationship between the credit cycle and happiness only during credit expansion. GDP per capita can moderate this relationship only during credit recession. Social support, freedom, and positive affect can moderate this relationship throughout the credit cycle. Third, the total impact of the credit cycle on happiness will become positive by the changes in the moderating effects. In general, we can improve subjective well-being if one of the following five conditions holds: (1) with the adequate support from the family and society, (2) with enough freedom, (3) with social generosity, (4) with a positive and optimistic outlook, and (5) with a high level of GDP per capita.