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The Lancet. Child & Adolescent Health Aug 2019The identification of preventive interventions that are safe and effective for cisplatin-induced ototoxicity is important, especially in children because hearing loss... (Review)
Review
The identification of preventive interventions that are safe and effective for cisplatin-induced ototoxicity is important, especially in children because hearing loss can impair speech-language acquisition development. Previous randomised trials assessed systemic drugs such as amifostine, sodium diethyldithiocarbamate or disulfiram, and sodium thiosulfate. Amifostine, sodium diethyldithiocarbamate, and disulfiram did not show hearing preservation. Paediatric trials assessing sodium thiosulfate showed efficacy in terms of hearing protection. The SIOPEL 6 trial consisted solely of patients with localised hepatoblastoma and no effects on survival were shown. In the ACCL0431 trial, which included heterogeneous patients, a post-hoc analysis showed significantly worse overall survival among patients who had disseminated disease receiving sodium thiosulfate than among controls, but not among those with localised disease. Intratympanically administered drugs have mainly been assessed in adults and include N-acetylcysteine and dexamethasone. Inconsistent effects of these drugs were identified but these studies were limited by design, small sample size, and statistical approach. Future studies of systemic drugs will need to consider the measurement of disease outcomes through study design and sample size, and ototoxicity endpoints should be harmonised to enhance comparability between trials.
Topics: Acetylcysteine; Adolescent; Amifostine; Anti-Inflammatory Agents; Antineoplastic Agents; Chelating Agents; Child; Cisplatin; Cytoprotection; Dexamethasone; Disulfiram; Ditiocarb; Humans; Neoplasms; Ototoxicity; Thiosulfates
PubMed: 31160205
DOI: 10.1016/S2352-4642(19)30115-4 -
PloS One 2018Dicyandiamide (DCD) and thiosulfates are two type of nitrification inhibitors (NIs) that have been widely used in agriculture to improve nitrogen (N) fertilizer use...
Dicyandiamide (DCD) and thiosulfates are two type of nitrification inhibitors (NIs) that have been widely used in agriculture to improve nitrogen (N) fertilizer use efficiency and mitigate negative effect of N on environment. Little information is available concerning the comparison of the efficacy of DCD and thiosulfate on N transformations in soil. The aim of this study was to compare the effects of DCD and thiosulfate (K2S2O3) on changes of NH4+-N, nitrification inhibition and N recovery in a latosolic red soil. An incubation experiment was conducted with four treatments of control (CK), N, N+DCD, and N+K2S2O3. Soil samples were collected periodically over 50 d to determine concentrations of mineral N, and the amoA gene abundance of ammonia monooxygenase (AMO) for ammonia-oxidizing bacteria (AOB) was estimated by qPCR after 10 d incubation. In the N treatment, 67.8% of the applied N as NH4+-N disappeared from the mineral N pool and only 2.7% and 30.8% of the applied N was accumulated as NO2--N and NO3--N, respectively. Addition of DCD and thiosulfate to the soil prevented NH4+-N disappearance by 63.0% and 13.6%, respectively. DCD suppressed the production of NO2--N by 97.41%, whereas thiosulfate increased accumulation of NO2--N by 14.6%. Application of N along with DCD and thiosulfate inhibited nitrification, respectively, by 72.6% and 33.1%, resulting in the delay of the nitrification process for 30 days and 10 days, respectively. Apparent N recovery in N treatment was 66.2%, which increased by 55.2% and 4.8% by DCD and thiosulfate, respectively. Numbers of AOB amoA gene copy was significantly inhibited by both DCD and thiosulfate, and the stronger inhibition induced by DCD than thiosulfate was recorded. Results indicated that both DCD and thiosulfate were effective inhibitors for NH4+-N oxidation, NO3--N production, mineral N losses and AOB growth. DCD showed a more pronounced effect on nitrification inhibition than thiosulfate.
Topics: Ammonia; Betaproteobacteria; Guanidines; Nitrification; Nitrogen; Oxidation-Reduction; Soil Microbiology; Thiosulfates
PubMed: 30106965
DOI: 10.1371/journal.pone.0200598 -
Redox Biology Jul 2022Heterotrophic bacteria and human mitochondria often use sulfide: quinone oxidoreductase (SQR) and persulfide dioxygenase (PDO) to oxidize sulfide to sulfite and...
Heterotrophic bacteria and human mitochondria often use sulfide: quinone oxidoreductase (SQR) and persulfide dioxygenase (PDO) to oxidize sulfide to sulfite and thiosulfate. Bioinformatic analysis showed that the genes encoding RHOD domains were widely presented in annotated sqr-pdo operons and grouped into three types: fused with an SQR domain, fused with a PDO domain, and dissociated proteins. Biochemical evidence suggests that RHODs facilitate the formation of thiosulfate and promote the reaction between inorganic polysulfide and glutathione to produce glutathione polysulfide. However, the physiological roles of RHODs during sulfide oxidation by SQR and PDO could only be tested in an RHOD-free host. To test this, 8 genes encoding RHOD domains in Escherichia coli MG1655 were deleted to produce E. coli RHOD-8K. The sqr and pdo genes from Cupriavidus pinatubonensis JMP134 were cloned into E. coli RHOD-8K. SQR contains a fused RHOD domain at the N-terminus. When the fused RHOD domain of SQR was inactivated, the cells oxidized sulfide into increased thiosulfate with the accumulation of cellular sulfane sulfur in comparison with cells containing the intact sqr and pdo. The complementation of dissociated DUF442 minimized the accumulation of cellular sulfane sulfur and reduced the production of thiosulfate. Further analysis showed that the fused DUF442 domain modulated the activity of SQR and prevented it from directly passing the produced sulfane sulfur to GSH. Whereas, the dissociated DUF442 enhanced the PDO activity by several folds. Both DUF442 forms minimized the accumulation of cellular sulfane sulfur, which spontaneously reacted with GSH to produce GSSG, causing disulfide stress during sulfide oxidation. Thus, RHODs may play multiple roles during sulfide oxidation.
Topics: Bacterial Proteins; Disulfides; Escherichia coli; Glutathione; Humans; Hydrogen Sulfide; Oxidation-Reduction; Quinone Reductases; Sulfides; Sulfur; Thiosulfate Sulfurtransferase; Thiosulfates
PubMed: 35653932
DOI: 10.1016/j.redox.2022.102345 -
The Journal of Biological Chemistry Nov 2019Thiosulfate dehydrogenases (TsdAs) are bidirectional bacterial di-heme enzymes that catalyze the interconversion of tetrathionate and thiosulfate at measurable rates in...
Thiosulfate dehydrogenases (TsdAs) are bidirectional bacterial di-heme enzymes that catalyze the interconversion of tetrathionate and thiosulfate at measurable rates in both directions. In contrast to our knowledge of TsdA activities, information on the redox properties in the absence of substrates is rather scant. To address this deficit, we combined magnetic CD (MCD) spectroscopy and protein film electrochemistry (PFE) in a study to resolve heme ligation and redox chemistry in two representative TsdAs. We examined the TsdAs from , a microaerobic human pathogen, and from the purple sulfur bacterium In these organisms, the enzyme functions as a tetrathionate reductase and a thiosulfate oxidase, respectively. The active site Heme 1 in both enzymes has His/Cys ligation in the ferric and ferrous states and the midpoint potentials ( ) of the corresponding redox transformations are similar, -185 mV standard hydrogen electrode (SHE). However, fundamental differences are observed in the properties of the second, electron transferring, Heme 2. In , TsdA Heme 2 has His/Met ligation and an of +172 mV. In TsdA, Heme 2 reduction triggers a switch from His/Lys ligation ( , -129 mV) to His/Met ( , +266 mV), but the rates of interconversion are such that His/Lys ligation would be retained during turnover. In summary, our findings have unambiguously assigned values to defined axial ligand sets in TsdAs, specified the rates of Heme 2 ligand exchange in the enzyme, and provided information relevant to describing their catalytic mechanism(s).
Topics: Campylobacter jejuni; Chromatiaceae; Circular Dichroism; Electrochemistry; Electron Transport; Heme; Oxidation-Reduction; Oxidoreductases; Thiosulfates
PubMed: 31467084
DOI: 10.1074/jbc.RA119.010084 -
International Journal of Molecular... Apr 2023Naphthoquinone (1,4-NQ) and its derivatives (NQs, juglone, plumbagin, 2-methoxy-1,4-NQ, and menadione) have a variety of therapeutic applications, many of which are...
Naphthoquinone (1,4-NQ) and its derivatives (NQs, juglone, plumbagin, 2-methoxy-1,4-NQ, and menadione) have a variety of therapeutic applications, many of which are attributed to redox cycling and the production of reactive oxygen species (ROS). We previously demonstrated that NQs also oxidize hydrogen sulfide (HS) to reactive sulfur species (RSS), potentially conveying identical benefits. Here we use RSS-specific fluorophores, mass spectroscopy, EPR and UV-Vis spectrometry, and oxygen-sensitive optodes to examine the effects of thiols and thiol-NQ adducts on HS-NQ reactions. In the presence of glutathione (GSH) and cysteine (Cys), 1,4-NQ oxidizes HS to both inorganic and organic hydroper-/hydropolysulfides (RS, R=H, Cys, GSH; = 2-4) and organic sulfoxides (GSOH, = 1, 2). These reactions reduce NQs and consume oxygen via a semiquinone intermediate. NQs are also reduced as they form adducts with GSH, Cys, protein thiols, and amines. Thiol, but not amine, adducts may increase or decrease HS oxidation in reactions that are both NQ- and thiol-specific. Amine adducts also inhibit the formation of thiol adducts. These results suggest that NQs may react with endogenous thiols, including GSH, Cys, and protein Cys, and that these adducts may affect both thiol reactions as well as RSS production from HS.
Topics: Sulfhydryl Compounds; Thiosulfates; Cysteine; Hydrogen Sulfide; Oxidation-Reduction; Glutathione; Proteins; Oxygen; Naphthoquinones
PubMed: 37108682
DOI: 10.3390/ijms24087516 -
Nature Communications Jun 2021Microbial sulfur metabolism contributes to biogeochemical cycling on global scales. Sulfur metabolizing microbes are infected by phages that can encode auxiliary...
Microbial sulfur metabolism contributes to biogeochemical cycling on global scales. Sulfur metabolizing microbes are infected by phages that can encode auxiliary metabolic genes (AMGs) to alter sulfur metabolism within host cells but remain poorly characterized. Here we identified 191 phages derived from twelve environments that encoded 227 AMGs for oxidation of sulfur and thiosulfate (dsrA, dsrC/tusE, soxC, soxD and soxYZ). Evidence for retention of AMGs during niche-differentiation of diverse phage populations provided evidence that auxiliary metabolism imparts measurable fitness benefits to phages with ramifications for ecosystem biogeochemistry. Gene abundance and expression profiles of AMGs suggested significant contributions by phages to sulfur and thiosulfate oxidation in freshwater lakes and oceans, and a sensitive response to changing sulfur concentrations in hydrothermal environments. Overall, our study provides fundamental insights on the distribution, diversity, and ecology of phage auxiliary metabolism associated with sulfur and reinforces the necessity of incorporating viral contributions into biogeochemical configurations.
Topics: Amino Acid Motifs; Bacteriophages; Caudovirales; Ecosystem; Energy Metabolism; Environmental Microbiology; Genes, Viral; Genetic Variation; Genome, Viral; Metagenomics; Oxidation-Reduction; Phylogeny; Protein Domains; Sulfur; Thiosulfates; Viral Proteins
PubMed: 34108477
DOI: 10.1038/s41467-021-23698-5 -
Applied Microbiology and Biotechnology Nov 2022Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the... (Review)
Review
Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the polysulfide pathway. These are determined by the metal sulfides' mineralogy and their acid solubility. The microbial cell enables metal sulfide dissolution via oxidation of iron(II) ions and inorganic sulfur compounds. Thereby, the metal sulfide attacking agents iron(III) ions and protons are generated. Cells are active either in a planktonic state or attached to the mineral surface, forming biofilms. This review, as an update of the previous one (Vera et al., 2013a), summarizes some recent discoveries relevant to bioleaching microorganisms, contributing to a better understanding of their lifestyle. These comprise phylogeny, chemical pathways, surface science, biochemistry of iron and sulfur metabolism, anaerobic metabolism, cell-cell communication, molecular biology, and biofilm lifestyle. Recent advances from genetic engineering applied to bioleaching microorganisms will allow in the future to better understand important aspects of their physiology, as well as to open new possibilities for synthetic biology applications of leaching microbial consortia. KEY POINTS: • Leaching of metal sulfides is strongly enhanced by microorganisms • Biofilm formation and extracellular polymer production influences bioleaching • Cell interactions in mixed bioleaching cultures are key for process optimization.
Topics: Thiosulfates; Protons; Ferric Compounds; Metals; Sulfides; Iron; Minerals; Sulfur; Polymers; Ferrous Compounds
PubMed: 36194263
DOI: 10.1007/s00253-022-12168-7 -
Microbiology Spectrum Aug 2022Thermotoga maritima is an anaerobic hyperthermophilic bacterium that efficiently produces H by fermenting carbohydrates. High concentration of H inhibits the growth of...
Thermotoga maritima is an anaerobic hyperthermophilic bacterium that efficiently produces H by fermenting carbohydrates. High concentration of H inhibits the growth of T. maritima, and S could eliminate the inhibition and stimulate the growth through its reduction. The mechanism of T. maritima sulfur reduction, however, has not been fully understood. Herein, based on its similarity with archaeal NAD(P)H-dependent sulfur reductases (NSR), the ORF THEMA_RS02810 was identified and expressed in Escherichia coli, and the recombinant protein was characterized. The purified flavoprotein possessed NAD(P)H-dependent S reductase activity (1.3 U/mg for NADH and 0.8 U/mg for NADPH), polysulfide reductase activity (0.32 U/mg for NADH and 0.35 U/mg for NADPH), and thiosulfate reductase activity (2.3 U/mg for NADH and 2.5 U/mg for NADPH), which increased 3~4-folds by coenzyme A stimulation. Quantitative RT-PCR analysis showed that was upregulated together with the , , and genes when the strain grew in S- or thiosulfate-containing medium. The mechanism for sulfur reduction in T. maritima was discussed, which may affect the redox balance and energy metabolism of T. maritima. Genome search revealed that NSR homolog is widely distributed in thermophilic bacteria and archaea, implying its important role in the sulfur cycle of geothermal environments. The reduction of S and thiosulfate is essential in the sulfur cycle of geothermal environments, in which thermophiles play an important role. Despite previous research on some sulfur reductases of thermophilic archaea, the mechanism of sulfur reduction in thermophilic bacteria is still not clearly understood. Herein, we confirmed the presence of a cytoplasmic NAD(P)H-dependent polysulfide reductase (NSR) from the hyperthermophile T. maritima, with S, polysulfide, and thiosulfate reduction activities, in contrast to other sulfur reductases. When grown in S- or thiosulfate-containing medium, its expression was upregulated. And the putative membrane-bound MBX and Rnf may also play a role in the metabolism, which might influence the redox balance and energy metabolism of T. maritima. This is distinct from the mechanism of sulfur reduction in mesophiles such as Wolinella succinogenes. NSR homologs are widely distributed among heterotrophic thermophiles, suggesting that they may be vital in the sulfur cycle in geothermal environments.
Topics: Archaea; Bacteria; NAD; NADP; Oxidation-Reduction; Oxidoreductases; Sulfur; Sulfurtransferases; Thermotoga maritima; Thiosulfates
PubMed: 35762779
DOI: 10.1128/spectrum.00436-22 -
MBio Apr 2022Life emerged and diversified in the absence of molecular oxygen. The prevailing anoxia and unique sulfur chemistry in the Paleo-, Meso-, and Neoarchean and early...
Life emerged and diversified in the absence of molecular oxygen. The prevailing anoxia and unique sulfur chemistry in the Paleo-, Meso-, and Neoarchean and early Proterozoic eras may have supported microbial communities that differ from those currently thriving on the earth's surface. Zodletone spring in southwestern Oklahoma represents a unique habitat where spatial sampling could substitute for geological eras namely, from the anoxic, surficial light-exposed sediments simulating a preoxygenated earth to overlaid water column where air exposure simulates oxygen intrusion during the Neoproterozoic era. We document a remarkably diverse microbial community in the anoxic spring sediments, with 340/516 (65.89%) of genomes recovered in a metagenomic survey belonging to 200 bacterial and archaeal families that were either previously undescribed or that exhibit an extremely rare distribution on the current earth. Such diversity is underpinned by the widespread occurrence of sulfite, thiosulfate, tetrathionate, and sulfur reduction and the paucity of sulfate reduction machineries in these taxa. Hence, these processes greatly expand lineages mediating reductive sulfur-cycling processes in the tree of life. An analysis of the overlaying oxygenated water community demonstrated the development of a significantly less diverse community dominated by well-characterized lineages and a prevalence of oxidative sulfur-cycling processes. Such a transition from ancient novelty to modern commonality underscores the profound impact of the great oxygenation event on the earth's surficial anoxic community. It also suggests that novel and rare lineages encountered in current anaerobic habitats could represent taxa that once thrived in an anoxic earth but have failed to adapt to earth's progressive oxygenation. Life on earth evolved in an anoxic setting; however, the identity and fate of microorganisms that thrived in a preoxygenated earth are poorly understood. In Zodletone spring, the prevailing geochemical conditions are remarkably similar to conditions prevailing in surficial earth prior to oxygen buildup in the atmosphere. We identify hundreds of previously unknown microbial lineages in the spring and demonstrate that these lineages possess the metabolic machinery to mediate a wide range of reductive sulfur processes, with the capacity to respire sulfite, thiosulfate, sulfur, and tetrathionate, rather than sulfate, which is a reflection of the differences in sulfur-cycling chemistry in ancient versus modern times. Collectively, such patterns strongly suggest that microbial diversity and sulfur-cycling processes in a preoxygenated earth were drastically different from the currently observed patterns and that the Great Oxygenation Event has precipitated the near extinction of a wide range of oxygen-sensitive lineages and significantly altered the microbial reductive sulfur-cycling community on earth.
Topics: Humans; Oxygen; Phylogeny; Sulfates; Sulfites; Sulfur; Thiosulfates; Water
PubMed: 35258328
DOI: 10.1128/mbio.00016-22 -
Kidney & Blood Pressure Research 2021Arterial stenosis activates the renin-angiotensin-aldosterone system subsequently resulting in renovascular hypertension (RVHT) and renal oxidative injury. We explored...
BACKGROUND/AIMS
Arterial stenosis activates the renin-angiotensin-aldosterone system subsequently resulting in renovascular hypertension (RVHT) and renal oxidative injury. We explored the effect of sodium thiosulfate (STS, Na2S2O3), a developed antioxidant in clinical trial, on RVHT-induced hypertension and renal oxidative injury in rats.
METHODS
We induced RVHT in male Wistar rats with bilaterally partial ligation of renal arteries in the 2-kidney 2-clip model. We evaluated the STS effect on RVHT-induced oxidative injury and apoptosis by a chemiluminescence amplification method, Western blot, and immunohistochemistry.
RESULTS
We found STS displayed a dose-dependent antioxidant H2O2 activity and adapted the maximal scavenging H2O2 activity of STS at the dosage of 0.1 g/kg intraperitoneally 3 times/week for 4 weeks in RVHT rats. RVHT induced a significant elevation of arterial blood pressure, blood reactive oxygen species amount, neutrophil infiltration, 4-HNE and NADPH oxidase gp91 expression, Bax/Bcl-2/poly(ADP-ribose) polymerase (PARP)-mediated apoptosis formation, blue Masson-stained fibrosis, and urinary protein level. STS treatment significantly reduced hypertension, oxidative stress, neutrophil infiltration, fibrosis, and Bax/Bcl-2/PARP-mediated apoptosis formation and depressed the urinary protein level in the RVHT models.
CONCLUSION
Our results suggest that STS treatment could ameliorate RVHT hypertension and renal oxidative injury through antioxidant, antifibrotic, and antiapoptotic mechanisms.
Topics: Animals; Antioxidants; Blood Pressure; Hypertension, Renovascular; Kidney; Male; Oxidative Stress; Rats, Wistar; Reactive Oxygen Species; Thiosulfates; Rats
PubMed: 33326967
DOI: 10.1159/000510047