Aix-Marseille Univ., CNRS, UMR 7281, Bioenergetics and Protein Engineering, 13402 Marseille, France.
Published: May 2020
AI Article Synopsis
Article Abstract
Getting information about the fate of immobilized enzymes and the evolution of their environment during turnover is a mandatory step toward bioelectrode optimization for effective use in biodevices. We demonstrate here the proof-of-principle visual characterization of the reactivity at an enzymatic electrode thanks to fluorescence confocal laser scanning microscopy (FCLSM) implemented in situ during the electrochemical experiment. The enzymatic O reduction involves proton-coupled electron transfers. Therefore, fluorescence variation of a pH-dependent fluorescent dye in the electrode vicinity enables reaction visualization. Simultaneous collection of electrochemical and fluorescence signals gives valuable space- and time-resolved information. Once the technical challenges of such a coupling are overcome, in situ FCLSM affords a unique way to explore reactivity at the electrode surface and in the electrolyte volume. Unexpected features are observed, especially the pH evolution of the enzyme environment, which is also indicated by a characteristic concentration profile within the diffusion layer. This coupled approach also gives access to a cartography of the electrode surface response (i.e., heterogeneity), which cannot be obtained solely by an electrochemical means.
Excessive reactive oxygen species (ROS) generated by ultraviolet (UV) irradiation significantly contribute to photoaging by increasing the level of matrix metalloproteinases (MMPs), accelerating collagen degradation. Commercial dermal fillers offer temporary wrinkle reduction via volume enhancement. In this study, we propose tilapia-derived collagen hydrogels embedded with ceria nanoparticles (Ce@Col gels) as long-lasting dermal fillers for UVB-induced photoaging.
Background: Environmental pollution, including exposure to carbon tetrachloride (CCl4), poses serious health risks, particularly through oxidative stress, which may lead to neurodegenerative damage. Antioxidants, especially those found in natural products, show potential in mitigating these toxic effects. Pomegranate juice (PJ), rich in bioactive phytochemicals, has demonstrated antioxidant, anti-inflammatory, and neuroprotective properties.
We propose a hybrid electrocatalytic-bioelectrocatalytic reaction cascade integrated on a gas diffusion electrode for CO2 reduction under selective formation of methanol. Ag-Bi2O3 selectively reduces gaseous CO2 to formate at neutral pH conditions. A subsequent enzymatic cascade comprising formaldehyde dehydro-genase and alcohol dehydrogenase, which are both nicotinamide adenine dinucleotide (NAD)-dependent, further reduce formate sequentially to formaldehyde and methanol.
Monoterpene indole alkaloids (MIAs) are a large, structurally diverse class of bioactive natural products. These compounds are biosynthetically derived from a stereoselective Pictet-Spengler condensation that generates a tetrahydro-β-carboline scaffold characterized by a 3 stereocenter. However, a subset of MIAs contain a non-canonical 3 stereocenter.
Hemes play key roles in enzymatic production of the mammalian gasotransmitter NO by nitric oxide synthase as well as in conversion from inorganic nitrite. In the present study, we report a hitherto unknown pathway of nitrosyl formation thiol reduction of a iron porphyrin nitrate complex in the solid state.
