Mitochondrial superoxide flash (mitoflash) reflects quantal and bursting superoxide production and concurrent membrane depolarization triggered by transient mitochondrial permeability transition in many types of cells, at the level of single mitochondria. Here we investigate reactive oxygen species (ROS)-mediated modulation of mitoflash activity in cardiac myocytes and report a surprising finding that hypochlorite ions potently and preferentially triggered mitoflashes in the subsarcolemmal mitochondria (SSM), whereas hydrogen peroxide (H2O2) elicited mitoflash activity uniformly among SSM and interfibrillar mitochondria (IFM). The striking SSM mitoflash response to hypochlorite stimulation remained intact in cardiac myocytes from NOX2-deficient mice, excluding local NOX2-mediated ROS as the major player. Furthermore, it occurred concomitantly with SSM Ca(2+) accumulation and local Ca(2+) and CaMKII signaling played an important modulatory role by altering frequency and unitary properties of SSM mitoflashes. These findings underscore the functional heterogeneity of SSM and IFM and the oxidant-specific responsiveness of mitochondria to ROS, and may bear important ramifications in devising therapeutic strategies for the treatment of oxidative stress-related heart diseases.

A high expression level of platelet Orai1/STIMI1 was associated with poor clinical outcome (mortality and recurrence) and functional recovery (SIS scores) during the 3-month follow-up. Thus, we propose that these proteins are strongly predictive of life quality in patients with IS.

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To effectively manipulate the electronic structure of the catalysts, we present here a simple bottom-up synthesis protocol for agglomerating palladium and cuprous oxide ultrasmall nanoclusters into single nanoparticles, forming so-called quantum dot assemblies (QDAs). Our synthesis is based on the galvanic displacement of copper with palladium cations under O2-free conditions, rendering the simultaneous and unique crystal growth of ∼3 nm Cu2O and Pd clusters. Such assemblies, comprising ultrasmall nanoconstitutes, offer much more phase boundaries, where the interfacial electronic effect becomes prominent in catalysis. This is demonstrated in the electrocatalytic oxidation of formaldehyde, ethanol, and glucose. In all three cases, the QDA catalyst, despite its similar Pd loading, outperforms the monometallic palladium catalyst. Indeed, complementing the experimental results with density functional theory calculations, we could confirm the sharply increased charge density at the Pd–Cu heterojunction and the decreased energy barrier of the formaldehyde oxidation on the QDA catalyst. Finally, we applied these catalysts in electroless copper deposition – an industrially relevant process for manufacturing printed circuit boards. The QDA catalysts gave uniform and robust copper wires at a rate that was three times faster than that of the monometallic Pd catalyst, showing their potential for real-life applications.