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Reactive sulfane sulfur species such as persulfides (RSSH) and H2S2 are important redox regulators and closely linked to H2S signaling. However, the study of these species is still challenging due to their instability, high reactivity, and the lack of suitable donors to produce them. Herein we report a unique compound, 2H-thiopyran-2-thione sulfine (TTS), which can specifically convert H2S to HSOH, and then to H2S2 in the presence of excess H2S. Meanwhile, the reaction product 2H-thiopyran-2-thione (TT) can be oxidized to reform TTS by biological oxidants. The reaction mechanism of TTS is studied experimentally and computationally. TTS can be conjugated to proteins to achieve specific delivery, and the combination of TTS and H2S leads to highly efficient protein persulfidation. When TTS is applied in conjunction with established H2S donors, the corresponding donors of H2S2 (or its equivalents) are obtained. Cell-based studies reveal that TTS can effectively increase intracellular sulfane sulfur levels and compensate for certain aspects of sulfide:quinone oxidoreductase (SQR) deficiency. These properties make TTS a conceptually new strategy for the design of donors of reactive sulfane sulfur species. Reactive sulfane sulfur species such as persulfides and H2S2 are important redox regulators and linked to H2S signaling, but their study is hindered by a lack of suitable donors to produce them. Here, the authors report 2H-thiopyran-2-thione sulfine (TTS), a compound which can specifically convert H2S to HSOH, and then to H2S2 in the presence of excess H2S. [ABSTRACT FROM AUTHOR]

Supersulphides are inorganic and organic sulphides with sulphur catenation with diverse physiological functions. Their synthesis is mainly mediated by mitochondrial cysteinyl-tRNA synthetase (CARS2) that functions as a principal cysteine persulphide synthase (CPERS). Here, we identify protective functions of supersulphides in viral airway infections (influenza and COVID-19), in aged lungs and in chronic lung diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF). We develop a method for breath supersulphur-omics and demonstrate that levels of exhaled supersulphides increase in people with COVID-19 infection and in a hamster model of SARS-CoV-2 infection. Lung damage and subsequent lethality that result from oxidative stress and inflammation in mouse models of COPD, IPF, and ageing were mitigated by endogenous supersulphides production by CARS2/CPERS or exogenous administration of the supersulphide donor glutathione trisulphide. We revealed a protective role of supersulphides in airways with various viral or chronic insults and demonstrated the potential of targeting supersulphides in lung disease. The physiological roles of supersulphides and the enzymes that trigger their production in various airway diseases are not fully understood. Here, the authors show in animal models of viral and chronic lung diseases that supersulphide production can mitigate lung pathology and lethal effects, highlighting their protective role and potential as a therapeutic target. [ABSTRACT FROM AUTHOR]

A kagome lattice (KL) is a two-dimensional atomic network comprising hexagons interspersed with triangles, which provides a fascinating platform for studying competing quantum ground states. The KL contains three atoms in a unit cell, and their degrees of freedom combine to yield Dirac bands and a flat band. Despite many studies to understand the flat band in KL, exploring the pseudospin of Dirac bands in KL has been scarce. In this paper, we suggest pseudospin-polarized scanning tunneling microscopy that is analogous to spin-polarized scanning tunneling microscopy. Using a pseudospin-polarized tip, we possibly observed the pseudospin texture of kagome metal FeSn in real space. Based on a simple tight-binding calculation, we further simulated the pseudospin texture of KL, confirming the geometric origin of pseudospin. This work potentially deepens our understanding of the lattice symmetry-preserving tunneling process in Dirac materials. Kagome Lattices provide a platform for studying competing quantum ground states. Lee and colleagues observed the pseudospin texture of FeSn in real space, deepening our understanding of the lattice symmetry-preserving tunneling process in Dirac materials. [ABSTRACT FROM AUTHOR]