In humans, sulfite is generated endogenously by the metabolism of sulfur containing amino acids such as methionine and cysteine. Sulfite is also formed from exposure to sulfur dioxide, one of the major environmental pollutants. Sulfite is used as an antioxidant and preservative in dried fruits, vegetables, and beverages such as wine. Sulfite is also used as a stabilizer in many drugs. Sulfite toxicity has been associated with allergic reactions characterized by sulfite sensitivity, asthma, and anaphylactic shock. Sulfite is also toxic to neurons and cardiovascular cells. Recent studies suggest that the cytotoxicity of sulfite is mediated by free radicals; however, molecular mechanisms involved in sulfite toxicity are not fully understood. Cytochrome c (cyt c) is known to participate in mitochondrial respiration and has antioxidant and peroxidase activities. Studies were performed to understand the related mechanism of oxidation of sulfite and radical generation by ferric cytochrome c (Fe cyt c) in the absence and presence of HO. Electron paramagnetic resonance (EPR) spin trapping studies using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were performed with sulfite, Fe cyt c, and HO. An EPR spectrum corresponding to the sulfite radical adducts of DMPO (DMPO-SO) was obtained. The amount of DMPO-SO formed from the oxidation of sulfite by the Fe cyt c increased with sulfite concentration. In addition, the amount of DMPO-SO formed by the peroxidase activity of Fe cyt c also increased with sulfite and HO concentration. From these results, we propose a mechanism in which the Fe cyt c and its peroxidase activity oxidizes sulfite to sulfite radical. Our results suggest that Fe cyt c could have a novel role in the deleterious effects of sulfite in biological systems due to increased production of sulfite radical. It also shows that the increased production of sulfite radical may be responsible for neurotoxicity and some of the injuries which occur to humans born with molybdenum cofactor and sulfite oxidase deficiencies.
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http://dx.doi.org/10.1016/j.bbrep.2015.11.025 | DOI Listing |
Cutis
November 2024
Solbie Choi is from the Albert Einstein College of Medicine, Bronx, New York. Sarak K. Zemlok is from the University of Connecticut School of Medicine, Farmington. Dr. Yu is from the Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston. Dr. Adler is from the Department of Dermatology, Keck School of Medicine, University of Southern California, Los Angeles.
The American Contact Dermatitis Society (ACDS) selected sulfites as the 2024 Allergen of the Year. These common and potentially allergenic ingredients are used as preservatives and antioxidants in a variety of foods, beverages, medications, and personal care products. In this article, we review common sources of sulfite exposure, clinical manifestations of allergic contact dermatitis (ACD) to sulfites, and patch testing considerations for this emerging allergen.
View Article and Find Full Text PDFPLoS One
January 2025
Faculty of Biology, VNU University of Science, Vietnam National University, Hanoi, Vietnam.
The autonomous and active Long-Interspersed Element-1 (LINE-1, L1) and the non-autonomous Alu retrotransposon elements, contributing to 30% of the human genome, are the most abundant repeated sequences. With more than 90% of their sequences being methylated in normal cells, these elements undeniably contribute to the global DNA methylation level and constitute a major part of circulating-cell-free DNA (cfDNA). So far, the hypomethylation status of LINE-1 and Alu in cellular and extracellular DNA has long been considered a prevailing hallmark of ageing-related diseases and cancer.
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January 2025
Group of Research in Ruminants (G2R), Department of Animal and Food Sciences, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Fiber is essential for rumen health, microbial fermentation, and the energy supply of herbivores. Even though the study of fecal fiber contents (neutral detergent fiber NDF, acid detergent fiber ADF, and acid detergent lignin ADL) using near-infrared reflectance spectroscopy (NIRS) has allowed investigating nutritional ecology of different herbivore species, NIRS calibrations are species-specific and require a large number of samples for predictions. A multispecies calibration would be an advantage since samples from different herbivores could be used to calibrate a model capable of predicting the fecal fiber content of other herbivores.
View Article and Find Full Text PDFAntioxidants (Basel)
November 2024
Barts & The London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK.
The majority of naturally occurring mutations of the human gene , are associated with reduced or completely absent xanthine oxidoreductase (XOR) activity, leading to a disease known as classical xanthinuria, which is due to the accumulation and excretion of xanthine in urine. Three types of classical xanthinuria have been identified: type I, characterised by XOR deficiency, type II, caused by XOR and aldehyde oxidase (AO) deficiency, and type III due to XOR, AO, and sulphite oxidase (SO) deficiency. Type I and II are considered rare autosomal recessive disorders, a condition where two copies of the mutated gene must be present to develop the disease or trait.
View Article and Find Full Text PDFTaurine and betaine are important nutrients in and have many important biological properties. To investigate the characteristics of taurine and betaine contents and identify SNPs associated with traits in the , we cloned the full-length cDNA of key genes in taurine and betaine (unpublished data) metabolism, determined taurine and betaine content and gene expression in different tissues and months of specimen collection, and developed SNPs in the gene coding region. We cloned the full-length cDNA of cysteine dioxygenase ( ) and cysteine sulfite decarboxylase ( ), which are key genes involved in taurine metabolism in , and found that betaine and taurine contents and the expression of key genes were regulated by seawater salinity.
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