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Proceedings of the National Academy of... Aug 2022Traditional sulfide metallurgy produces harmful sulfur dioxide and is energy intensive. To this end, we develop an anode electrolysis approach in molten salt by which...
Traditional sulfide metallurgy produces harmful sulfur dioxide and is energy intensive. To this end, we develop an anode electrolysis approach in molten salt by which sulfide is electrochemically split into sulfur gas at a graphite inert anode while releasing metal ions that diffuse toward and are deposited at the cathode. The anodic splitting dictates the "sulfide-to-metal ion and sulfur gas" conversion that makes the reaction recur continuously. Using this approach, CuS is converted to sulfur gas and Cu in molten LiCl-KCl at 500 °C with a current efficiency of 99% and energy consumption of 0.420 kWh/kg (only considering the electricity for electrolysis). Besides CuS, the anode electrolysis can extract Cu from Cu matte that is an intermediate product from the traditional sulfide smelting process. More broadly, Fe, Ni, Pb, and Sb are extracted from FeS, CuFeS, NiS, PbS, and SbS, providing a general electrochemical method for sulfide metallurgy.
Topics: Electrodes; Electrolysis; Graphite; Metals; Sulfides; Sulfur
PubMed: 35878036
DOI: 10.1073/pnas.2202884119 -
Nitric Oxide : Biology and Chemistry Nov 2021Sulfides and persulfides/polysulfides (R-S-R', n > 2; R-S-H, n > 1) are endogenously produced metabolites that are abundant in mammalian and human cells and tissues....
Sulfides and persulfides/polysulfides (R-S-R', n > 2; R-S-H, n > 1) are endogenously produced metabolites that are abundant in mammalian and human cells and tissues. The most typical persulfides that are widely distributed among different organisms include various reactive persulfides-low-molecular-weight thiol compounds such as cysteine hydropersulfide, glutathione hydropersulfide, and glutathione trisulfide as well as protein-bound thiols. These species are generally more redox-active than are other simple thiols and disulfides. Although hydrogen sulfide (HS) has been suggested for years to be a small signaling molecule, it is intimately linked biochemically to persulfides and may actually be more relevant as a marker of functionally active persulfides. Reactive persulfides can act as powerful antioxidants and redox signaling species and are involved in energy metabolism. Recent evidence revealed that cysteinyl-tRNA synthetases (CARSs) act as the principal cysteine persulfide synthases in mammals and contribute significantly to endogenous persulfide/polysulfide production, in addition to being associated with a battery of enzymes including cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfurtransferase, which have been described as HS-producing enzymes. The reactive sulfur metabolites including persulfides/polysulfides derived from CARS2, a mitochondrial isoform of CARS, also mediate not only mitochondrial biogenesis and bioenergetics but also anti-inflammatory and immunomodulatory functions. The physiological roles of persulfides, their biosynthetic pathways, and their pathophysiology in various diseases are not fully understood, however. Developing basic and high precision techniques and methods for the detection, characterization, and quantitation of sulfides and persulfides is therefore of great importance so as to thoroughly understand and clarify the exact functions and roles of these species in cells and in vivo.
Topics: Animals; Cell Line; Chemistry Techniques, Analytical; Humans; Hydrogen Sulfide; Protein Processing, Post-Translational; Proteins; Proteomics; Sulfides
PubMed: 34534626
DOI: 10.1016/j.niox.2021.09.002 -
Chemical & Pharmaceutical Bulletin 2017We examined the sulfides in onion (Allium cepa L.), Welsh onion (A. fistulosum L.), and garlic (A. sativum L.), and obtained three new thiolane-type sulfides (onionins... (Review)
Review
We examined the sulfides in onion (Allium cepa L.), Welsh onion (A. fistulosum L.), and garlic (A. sativum L.), and obtained three new thiolane-type sulfides (onionins A-A) from onion; two new thiabicyclic-type sulfides (welsonins A, A), together with onionins A-A, from Welsh onion; and six new acyclic-type sulfides (garlicnins L-1-L-4, E, and F), ten new thiolane-type sulfides (garlicnins A, B-B, C-C, K, and K), and three new atypical cyclic-type sulfides (garlicnins G, I, and J) from garlic. Acetone extracts showed the potential of these sulfides in inhibiting the polarization of M2 activated macrophages that are capable of suppressing tumor-cell proliferation. The effect of the thiolane-type sulfide of a major component, onionin A, on tumor progression and metastasis in both osteosarcoma and ovarian cancer-bearing mouse models was then examined. Tumor proliferation was depressed, and tumor metastasis was controlled by regulating macrophage activation. These results showed that onionin A is an effective agent for controlling tumors in both in vitro and in vivo models, and that the antitumor effects observed in vivo are likely caused by reversing the antitumor immune system. Activation of the antitumor immune system by onionin A might be an effective adjuvant therapy for patients with osteosarcoma, ovarian cancer and other malignant tumors. Based on these findings, pharmacological investigations will be conducted in the future to develop natural and healthy foods and anti-cancer agents that can prevent or combat disease.
Topics: Allium; Animals; Antineoplastic Agents, Phytogenic; Cell Proliferation; Humans; Neoplasms; Onions; Sulfides
PubMed: 28250342
DOI: 10.1248/cpb.c16-00844 -
Proceedings of the Japan Academy.... 2015Hydrogen sulfide (H2S) is a familiar toxic gas that smells of rotten eggs. After the identification of endogenous H2S in the mammalian brain two decades ago, studies of... (Review)
Review
Hydrogen sulfide (H2S) is a familiar toxic gas that smells of rotten eggs. After the identification of endogenous H2S in the mammalian brain two decades ago, studies of this molecule uncovered physiological roles in processes such as neuromodulation, vascular tone regulation, cytoprotection against oxidative stress, angiogenesis, anti-inflammation, and oxygen sensing. Enzymes that produce H2S, such as cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfurtransferase have been studied intensively and well characterized. Polysulfides, which have a higher number of inner sulfur atoms than that in H2S, were recently identified as potential signaling molecules that can activate ion channels, transcription factors, and tumor suppressors with greater potency than that of H2S. This article focuses on our contribution to the discovery of these molecules and their metabolic pathways and mechanisms of action.
Topics: Animals; Cytoprotection; Humans; Hydrogen Sulfide; Nitric Oxide; Signal Transduction; Sulfides; Synaptic Transmission
PubMed: 25864468
DOI: 10.2183/pjab.91.131 -
Nitric Oxide : Biology and Chemistry Apr 2015Sulfide (H2S/HS(-)) has been demonstrated to exert an astounding breadth of biological effects, some of which resemble those of nitric oxide (NO). While the chemistry,... (Review)
Review
Sulfide (H2S/HS(-)) has been demonstrated to exert an astounding breadth of biological effects, some of which resemble those of nitric oxide (NO). While the chemistry, biochemistry and potential pathophysiology of the cross-talk between sulfide and NO have received considerable attention lately, a comparable assessment of the potential biological implications of an interaction between nitrite and sulfide is lacking. This is surprising inasmuch as nitrite is not only a known bioactive oxidation product of NO, but also efficiently converted to S-nitrosothiols in vivo; the latter have been shown to rapidly react with sulfide in vitro, leading to formation of S/N-hybrid species including thionitrite (SNO(-)) and nitrosopersulfide (SSNO(-)). Moreover, nitrite is used as a potent remedy against sulfide poisoning in the clinic. The chemistry of interaction between nitrite and sulfide or related bioactive metabolites including polysulfides and elemental sulfur has been extensively studied in the past, yet much of this information appears to have been forgotten. In this review, we focus on the potential chemical biology of the interaction between nitrite and sulfide or sulfane sulfur molecules, calling attention to the fundamental chemical properties and reactivities of either species and discuss their possible contribution to the biology, pharmacology and toxicology of both nitrite and sulfide.
Topics: Animals; Biochemistry; Humans; Nitric Oxide; Nitrites; Organ Specificity; Sulfides
PubMed: 25541073
DOI: 10.1016/j.niox.2014.12.009 -
Antioxidants & Redox Signaling Jul 2023Protein persulfidation (the formation of RSSH), an evolutionarily conserved oxidative posttranslational modification in which thiol groups in cysteine residues are... (Review)
Review
Protein persulfidation (the formation of RSSH), an evolutionarily conserved oxidative posttranslational modification in which thiol groups in cysteine residues are converted into persulfides, has emerged as one of the main mechanisms through which hydrogen sulfide (HS) conveys its signaling. New methodological advances in persulfide labeling started unraveling the chemical biology of this modification and its role in (patho)physiology. Some of the key metabolic enzymes are regulated by persulfidation. RSSH levels are important for the cellular defense against oxidative injury, and they decrease with aging, leaving proteins vulnerable to oxidative damage. Persulfidation is dysregulated in many diseases. A relatively new field of signaling by protein persulfidation still has many unanswered questions: the mechanism(s) of persulfide formation and transpersulfidation and the identification of "protein persulfidases," the improvement of methods to monitor RSSH changes and identify protein targets, and understanding the mechanisms through which this modification controls important (patho)physiological functions. Deep mechanistic studies using more selective and sensitive RSSH labeling techniques will provide high-resolution structural, functional, quantitative, and spatiotemporal information on RSSH dynamics and help with better understanding how HS-derived protein persulfidation affects protein structure and function in health and disease. This knowledge could pave the way for targeted drug design for a wide variety of pathologies. 39, 19-39.
Topics: Sulfides; Hydrogen Sulfide; Signal Transduction; Oxidative Stress; Oxidation-Reduction; Biology
PubMed: 37288744
DOI: 10.1089/ars.2023.0352 -
Biomolecules Apr 2020We have been studying the general aspects of the functions of HS and polysulfides, and the enzymes involved in their biosynthesis, for more than 20 years. Our aim has...
We have been studying the general aspects of the functions of HS and polysulfides, and the enzymes involved in their biosynthesis, for more than 20 years. Our aim has been to elucidate novel physiological and pathological functions of HS and polysulfides, and unravel the regulation of the enzymes involved in their biosynthesis, including cystathionine β-synthase (EC 4.2.1.22), cystathionine γ-lyase (EC 4.4.1.1), thiosulfate sulfurtransferase (rhodanese, EC 2.8.1.1), and 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2). Physiological and pathological functions, alternative biosynthetic processes, and additional functions of HS and polysulfides have been reported. Further, the structure and reaction mechanisms of related enzymes have also been reported. We expect this issue to advance scientific knowledge regarding the detailed functions of HS and polysulfides as well as the general properties and regulation of the enzymes involved in their metabolism. We would like to cover four topics: the physiological and pathological functions of HS and polysulfides, the mechanisms of the biosynthesis of HS and polysulfides, the properties of the biosynthetic enzymes, and the regulation of enzymatic activity. The knockout mouse technique is a useful tool to determine new physiological functions, especially those of HS and polysulfides. In the future, we shall take a closer look at symptoms in the human congenital deficiency of each enzyme. Further studies on the regulation of enzymatic activity by in vivo substances may be the key to finding new functions of HS and polysulfides.
Topics: Animals; Disease; Enzymes; Gene Knockout Techniques; Humans; Hydrogen Sulfide; Sulfides
PubMed: 32326219
DOI: 10.3390/biom10040640 -
Molecules (Basel, Switzerland) Oct 2014Hydrogen sulfide (H2S) is recognized as a biological mediator with various roles such as neuromodulation, regulation of the vascular tone, cytoprotection,... (Review)
Review
Hydrogen sulfide (H2S) is recognized as a biological mediator with various roles such as neuromodulation, regulation of the vascular tone, cytoprotection, anti-inflammation, oxygen sensing, angiogenesis, and generation of mitochondrial energy. It is produced by cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3MST). The activity of CBS is enhanced by S-adenosyl methionine (SAM) and glutathionylation, while it is inhibited by nitric oxide (NO) and carbon monoxide (CO). The activity of CSE and cysteine aminotransferase (CAT), which produces the 3MST substrate 3-mercaptopyruvate (3MP), is regulated by Ca2+. H2S is oxidized to thiosulfate in mitochondria through the sequential action of sulfide quinone oxidoreductase (SQR), sulfur dioxygenase, and rhodanese. The rates of the production and clearance of H2S determine its cellular concentration. Polysulfides (H2Sn) have been found to occur in the brain and activate transient receptor potential ankyrin 1 (TRPA1) channels, facilitate the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus, and suppress the activity of phosphatase and tensin homolog (PTEN) by sulfurating (sulfhydrating) the target cysteine residues. A cross talk between H2S and NO also plays an important role in cardioprotection as well as regulation of the vascular tone. H2S, polysulfides, and their cross talk with NO may mediate various physiological and pathophysiological responses.
Topics: Hydrogen Sulfide; Nitric Oxide; Sulfides
PubMed: 25302704
DOI: 10.3390/molecules191016146 -
Nano Letters Mar 2020Semiconductor quantum dots (QDs) are attractive fluorescent contrast agents for imaging due to their superior photophysical properties, but traditional QDs comprise...
Semiconductor quantum dots (QDs) are attractive fluorescent contrast agents for imaging due to their superior photophysical properties, but traditional QDs comprise toxic materials such as cadmium or lead. Copper indium sulfide (CuInS, CIS) QDs have been posited as a nontoxic and potentially clinically translatable alternative; however, previous studies utilized particles with a passivating zinc sulfide (ZnS) shell, limiting direct evidence of the biocompatibility of the underlying CIS. For the first time, we assess the biodistribution and toxicity of unshelled CIS and partially zinc-alloyed CISZ QDs in a murine model. We show that bare CIS QDs breakdown quickly, inducing significant toxicity as seen in organ weight, blood chemistry, and histology. CISZ demonstrates significant, but lower, toxicity compared to bare CIS, while our measurements of core/shell CIS/ZnS are consistent with literature reports of general biocompatibility. cytotoxicity is dose-dependent on the amount of metal released due to particle degradation, linking degradation to toxicity. These results challenge the assumption that removing heavy metals necessarily reduces toxicity: indeed, we find comparable cytotoxicity between CIS and CdSe QDs, while CIS caused severe toxicity compared to CdSe. In addition to highlighting the complexity of nanotoxicity and the differences between the and outcomes, these unexpected results serve as a reminder of the importance of assessing the biocompatibility of core QDs absent the protective ZnS shell when making specific claims of compositional biocompatibility.
Topics: Animals; Copper; Cytotoxins; Dose-Response Relationship, Drug; Female; Hep G2 Cells; Humans; Indium; Mice; Mice, Inbred BALB C; Quantum Dots; Sulfides
PubMed: 31999467
DOI: 10.1021/acs.nanolett.9b05259 -
The Journal of Nutrition Feb 2016For centuries, garlic has been shown to exert substantial medicinal effects and is considered to be one of the best disease-preventative foods. Diet is important in the... (Review)
Review
For centuries, garlic has been shown to exert substantial medicinal effects and is considered to be one of the best disease-preventative foods. Diet is important in the maintenance of health and prevention of many diseases including cardiovascular disease (CVD). Preclinical and clinical evidence has shown that garlic reduces risks associated with CVD by lowering cholesterol, inhibiting platelet aggregation, and lowering blood pressure. In recent years, emerging evidence has shown that hydrogen sulfide (H2S) has cardioprotective and cytoprotective properties. The active metabolite in garlic, allicin, is readily degraded into organic diallyl polysulfides that are potent H2S donors in the presence of thiols. Preclinical studies have shown that enhancement of endogenous H2S has an impact on vascular reactivity. In CVD models, the administration of H2S prevents myocardial injury and dysfunction. It is hypothesized that these beneficial effects of garlic may be mediated by H2S-dependent mechanisms. This review evaluates the current knowledge concerning the cardioprotective effects of garlic-derived diallyl polysulfides.
Topics: Cardiovascular Agents; Disulfides; Garlic; Heart; Humans; Hydrogen Sulfide; Myocardium; Phytotherapy; Plant Extracts; Sulfides; Sulfinic Acids
PubMed: 26764335
DOI: 10.3945/jn.114.208066