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This work proposes an analytical method based on digital images to indirectly determine bisulfite in vinegar samples using the colorimetric reaction between Fe(II) and the complexing agent 2,2′-bipyridine. Optimization was conducted using a multivariate methodology. Firstly, a two-level full factorial design was performed to identify the factors with significant effects on the analytical response through a two-level full factorial design (23). The studied variables included pH, 2,2′-bipyridine concentration, and sample volume. Subsequently, a Doehlert matrix was employed to establish the optimal conditions for the significant variables. The recommended procedure involved a reaction pH of 5.7 and a 0.0038 mol L−1 2,2′-bipyridine concentration, with a sample volume of 0.75 mL. The proposed method exhibited a linear response within the range of 0.45 to 300 mg L−1 of bisulfite, with detection and quantification limits of 0.15 mg L−1 and 0.45 mg L−1, respectively. The method's precision, assessed through relative standard deviation, was 3.4% (n = 10, 1.0 mg L−1). Accuracy was evaluated through recovery tests, with results ranging from 97 to 114%. Furthermore, a comparison was made between the bisulfite concentrations determined using the proposed method and those obtained through a reference method based on iodometric titration. The method was successfully applied to determine bisulfite in commercial vinegar samples. The bisulfite concentration varied from (14 ± 1) mg L−1 to (261 ± 3) mg L−1. [ABSTRACT FROM AUTHOR]

DNA methylation influences regulation of gene expression during cell development and tissue differentiation in plants. This study therefore discussed the role of DNA methylation in the recovery of maize from Maize Streak Diseases (MSD). Bisulfite treatment and DNA sequencing methods were carried out on the 2nd, 4th 6th and 8th white to yellowish streaking leaves of five infected maize varieties (DMR-ESR-Y, TZEBR, and ART/98/SW6) to assess the disease severity using digital phenotyping. The bisulfite treatment utilizes various sensitivities of cytosine and 5-methylcytosine (5-MeC) to deamination by bisulfite under acidic conditions in which cytosine is converted to uracil, whereas 5-MeC remains unreactive. This study showed that DMR-ESR-Y variety significantly (p

Diclofenac (DCF) is often detected in diverse aquatic bodies, and ineffective management can lead to detrimental effects on human health and ecosystems. In this study, degradation of DCF by Fe(III) and Mn(II) activating bisulfite (BS) was investigated. In the Fe(III)/Mn(II)/BS system, 93.4% DCF was degraded at 200 μM BS within 120 s, and additional research on 1000 μM BS achieved 88.4% degradation efficacy. Moreover, kinetics fitting of DCF degradation with the different BS concentrations was studied to find the two highest reaction rates (200 and 1000 μM, kobs = 0.0297 and 0.0317 s−1, respectively). Whereafter, SO4•− and Mn(III) were identified as the main active species at these two concentrations, respectively. Density functional theory (DFT) calculations, molecular frontier orbital theory, and surface electrostatic potential (ESP) forecast electrophilic attack sites. DCF degradation pathways by radical and non-radical ways were proposed by attack site prediction and thirteen intermediates identified by UPLC-QTOF-MS. ECOSAR software 2.2 was used for toxicity assessment. This work studied DCF degradation by the Fe(III)/Mn(II)/BS process in the presence of different concentrations of BS, providing a new insight into water purification. [ABSTRACT FROM AUTHOR]

Quenching of excess aqueous ozone (O3) residual is needed to avoid off-gassing and oxidative damage to downstream components. Eight quenching agents (QAs), calcium thiosulfate (Ca-Thio), sodium bisulfite (Na-Bi), hydrogen peroxide (H2O2), sodium thiosulfate (Na-Thio), sodium metabisulfite (Na-Metabi), potassium metabisulfite (K-Metabi), sodium sulfite (Na-S), and ascorbic acid (AscAcid) were tested at varying pHs (7.5, 7.9, and 8.5) and temperatures (4°C, 15°C, and 23°C). Temperature had significant effects on initial quenching (≤30 s), with less occurring at 4°C than 23°C; but with extended contact time this trend reversed. Quenching efficiency was not substantially affected by pH. Ca-Thio and Na-Thio were inefficient but quick, had lower mass requirements, and minimal handling concerns. Na-Metabi, Na-Bi, and Na-S were quick and efficient, but K-Metabi was the only QA that quenched (26–31%) less O3 than stoichiometry at all conditions. These sulfite-based QAs had more handling concerns and greater mass requirements. H2O2 was slower than other QAs but 2–9× quicker than predicted by rate coefficients and efficient when given longer contact time (≤5 min). H2O2 had some handling concerns but the lowest mass requirements (assuming 5 min contact time) and creates desirable AOP conditions. AscAcid consistently quenched (22–113%) more O3 than the stoichiometric ratio but had higher mass requirements, except in colder temperatures. Hydrodynamics, QA-diffuser design, and supply chain were also important considerations. [ABSTRACT FROM AUTHOR]

Candlenuts can be used as a substitute in producing chocolate spread due to their high-fat content. However, the limitation of using candlenut in the spread formulation is the existence of a bitter taste. This study aimed to investigate the effect of sodium bisulfite and sodium bicarbonate soaking treatment (100, 300, and 500 ppm) on reducing the bitter taste of candlenut seed. In order to reach the goal, bitter compounds of candlenut and chocolate spread were identified using Liquid chromatography-mass spectrometry (LC-MS). The sensory characteristics of chocolate spread were profiled using the Rate All That Apply (RATA) descriptive method. It was shown that the panelists identified 14 sensory attributes in the samples, one of which was bitter taste. Treatment with sodium bisulfite, as well as sodium bicarbonate at the level of 300 ppm, reduced the intensity of the bitter taste. The treatment reduced flavonoid and tannin levels by 85.21% and 82.08% in candlenut seeds. It also reduced flavonoid and tannin levels by 88.47% and 72.71% in chocolate spread, respectively. LC-MS identified 13 compounds that cause the bitter taste, namely quercetin, oleuropein, kaemferol, resveratrol dimer, luteolin, epicatechin, theobromine, caffeine, iso-humolones, colaflavone, chlorogenic acid, feruloyl-caffeoylquinic acid, and coumaroylquinic acid. This study creates a new technique for producing chocolate spread formulated with candlenuts with lower bitterness levels.

Drought is an enormous threat to global crop production. In order to ensure food security for the burgeoning population, we must develop drought tolerant crop varieties. This necessitates the identification of drought-responsive genes and understanding the mechanisms involved in their regulation. DNA methylation is a widely studied mechanism of epigenetic regulation of gene expression, which is known to play vital role in conferring tolerance to various biotic and abiotic stress factors. The recent advances in next-generation sequencing (NGS) technologies, has allowed unprecedented access to genome-wide methylation marks, with single base resolution. The most important roles of DNA methylation have been studied in terms of gene body methylation (gbM), which is associated with regulation of both transcript abundance and its stability. The availability of mutants for the various genes encoding enzymes involved in methylation of DNA has allowed ascertainment of the biological significance of methylation. Even though a vast number of reports have emerged in the recent past, where both genome-wide methylation landscape and locus specific changes in DNA methylation have been studied, a conclusive picture with regards to the biological role of DNA methylation is still lacking. Compounding this, is the lack of sufficient evidence supporting the heritability of these epigenetic changes. Amongst the various epigenetic variations, the DNA methylation changes are observed to be the most stable. This review describes the drought-induced changes in DNA methylation identified across different plant species. We also briefly describe the stress memory contributed by these changes. The identification of heritable, drought-induced methylation marks would broaden the scope of crop improvement in the future. [ABSTRACT FROM AUTHOR]

In this study, permanganate combined with bisulfite (PM/BS), a novel advanced oxidation process, was used for rapidly removing sulfamethoxazole (SMX) from contaminated water. The results showed that 80% SMX was removed within 10 s in the PM/BS system, while no obvious SMX degradation was observed in the PM or BS alone system within 300 s. Reactive manganese species (RMnS, Mn(III), Mn(V) and Mn(VI)), sulfate radical (SO4•−) and hydroxyl radical (HO•) formed in the PM/BS system all played a role in accelerated degradation of SMX. Due to the loss of RMnS, SMX degradation was significantly inhibited with the increase in pH. The best [BS]:[PM] ratio for SMX removal was 7.5:1-10:1. The presence of Cl−, HCO3− or natural organic matter (NOM) significantly inhibited the degradation of SMX, while SO42− and NO3− had little impact on SMX removal. Based on the detected transformation products, two degradation pathways of SMX by PM/BS, namely N-S bond cleavage and amino oxidation, were proposed. [ABSTRACT FROM AUTHOR]

Diclofenac (DCF) is often detected in diverse aquatic bodies, and ineffective management can lead to detrimental effects on human health and ecosystems. In this study, degradation of DCF by Fe(III) and Mn(II) activating bisulfite (BS) was investigated. In the Fe(III)/Mn(II)/BS system, 93.4% DCF was degraded at 200 μM BS within 120 s, and additional research on 1000 μM BS achieved 88.4% degradation efficacy. Moreover, kinetics fitting of DCF degradation with the different BS concentrations was studied to find the two highest reaction rates (200 and 1000 μM, kobs = 0.0297 and 0.0317 s−1, respectively). Whereafter, SO4•− and Mn(III) were identified as the main active species at these two concentrations, respectively. Density functional theory (DFT) calculations, molecular frontier orbital theory, and surface electrostatic potential (ESP) forecast electrophilic attack sites. DCF degradation pathways by radical and non-radical ways were proposed by attack site prediction and thirteen intermediates identified by UPLC-QTOF-MS. ECOSAR software 2.2 was used for toxicity assessment. This work studied DCF degradation by the Fe(III)/Mn(II)/BS process in the presence of different concentrations of BS, providing a new insight into water purification.

[Display omitted] • A dual-response florescent probe based on phenanthroimidazole for N 2 H 4 and HSO 3 – detection was developed. • EPC for N 2 H 4 and HSO 3 – detection displayed low detection limits of 0.182 µM and 0.093 µM, respectively. • EPC based test paper can be used as a simple device for quantitative determining of N 2 H 4 in environmental samples. • Probe EPC was feasible for the detection of HSO 3 – in food samples. Hydrazine (N 2 H 4) and bisulfite (HSO 3 –) detection methods are urgently needed due to its harmful to the human health and environment safety. Herein, we reported a dual-response fluorescence probe EPC , which is capable of sequential detection of N 2 H 4 and HSO 3 – by two different fluorescence signals. The probe EPC itself showed yellow florescence. In presence of N 2 H 4 , probe EPC exhibited an obviously fluorescence change (from yellow to green). However, a new addition product came into being after probe EPC mixed with HSO 3 –, followed with weak yellow emission. More important, probe EPC exhibited excellent fluorescence response properties for N 2 H 4 and HSO 3 –, such as high sensitivity (0.182 µM for N 2 H 4 , 0.093 µM for HSO 3 –), rapid response (55 s for N 2 H 4 , 45 s for HSO 3 –), excellent selectivity and anti-interference performance. The sensing mechanisms for N 2 H 4 and HSO 3 – were proved by 1H NMR and MS spectra. Practical applications were studied. EPC based test paper can be utilized for quantitative detecting N 2 H 4 in actual water samples. And, probe EPC has been successfully applied to recognize N 2 H 4 contaminant in soil samples. Moreover, EPC has great potential to be used to detect HSO 3 – in real food samples. [ABSTRACT FROM AUTHOR]

Biomercaptan, bisulfite (HSO 3 −) and hydrogen sulfide (H 2 S) are involved in many physiological and pathological processes in the human body. Therefore, it is of great significance to develop a fluorescent probe that can simultaneously detect and distinguish biological mercaptans from HSO 3 − and S2−. The probe CDI-1 was synthesized by combining coumarin with hemicyanine. The maximum absorption wavelength of the probe is at 609 nm. After adding Cys/Hcy and GSH, the probe shows varying degrees of blue shift, which can be used to distinguish Cys/Hcy and GSH. After it reacts with Cys/Hcy, the fluorescence intensity of the solution increases about twice, while it increases three times after it reacts with GSH. This phenomenon can also be used to distinguish Cys/Hcy from GSH. The probe CDI-1 can react with Cys completely within 30 min, with Hcy or GSH completely within 80 min, and with HSO 3 − and S2− quickly within 20 min. The study on the effect of pH on the fluorescence performance of CDI-1 shows that the probe is suitable for detecting biological mercaptan or HSO 3 −, S2− in weak acid to weak alkali environments. The selectivity study showed that the probe CDI-1 had high specificity for biological mercaptan, HSO 3 − and S2−. This provides a new and simple method for simultaneous detection of biological mercaptan, HSO 3 − and S2− ions. UV–Vis absorption spectra of CDI-1 interaction with small molecules. Solvent: EtOH/PBS (v/v, 5/5, pH = 7.4); CDI-1: 20 μM; Analytes: Cys, Hcy, GSH, Thr, Ile, His, Glu, Ala, Gly, Ser, Met, Phe, Pro, Leu, Asn, Lys, Val, S2−, HSO 3 − (200 μM)CDI-1 has specificity for the detection of HSO 3 −, S2− and biothiols. [Display omitted] • The probe CDI-1 had high specificity for biological mercaptan, HSO 3 − and S2-. • The probe CDI-1 can simultaneously detect biothiols and HSO 3 − and S2-. • CDI-1 has good stability in weak acid and weak base environments. [ABSTRACT FROM AUTHOR]

The emission of venenous sulfur dioxide (SO 2) and its derivatives from industrial applications such as coking, transportation and food processing has caused great concern about public health and environmental quality. Probes that enable sensitivity and specificity to detect SO 2 derivatives play a crucial role in its regulations and finally mitigating its environmental and health impacts, but fluorescent probes that can accurately, rapidly and on-site detect SO 2 derivatives in foodstuffs and environmental systems rarely reported. Herein, a near-infrared (NIR) fluorescent probe (ZTX) for the ratiometric response of bisulfite (HSO 3 −) was designed and synthesized by regulating the structure of high-performance HSO 3 − fluorescent probe SL previously reported by us based on structural analyses, theoretical calculations and related literature reports. The Michael addition reaction between the electronic-deficient C=C bond and HSO 3 − destroys ZTX 's π-conjugation system and blocks its intramolecular charge transfer (ICT) process, resulting in a significant fading of the fuchsia solution and the bluish-purple fluorescence turned light blue fluorescence. Fluorescent imaging of HSO 3 − in live animals utilizing ZTX has been demonstrated. The quantitative analysis of HSO 3 − in food samples using ZTX via a smartphone has been also successfully implemented. Simultaneously, the ZTX -based test strips were utilized to quantificationally determine HSO 3 − in environmental water samples by a smartphone. Consequently, probe ZTX could provide a new method to understand the physiopathological roles of HSO 3 −, evaluate food safety and monitor environment, and is promising for broad applications. [Display omitted] • The fluorescence probe ZTX features NIR-emitting (849 nm), large Stokes shift (326 nm) and high biocompatibility. • The quantitative determination of HSO 3 − in environmental water and actual food sampleswere realized using ZTX combined with a smartphone. • Applications of ZTX in fluorescence imaging of HSO 3 − in vivo in mouse model are successfully demonstrated. [ABSTRACT FROM AUTHOR]

Fluorescence probes bearing malononitrile derivatives as electron withdrawing group have attracted the interests of many researchers during the past decades. Even for the similar fluorophore, the sensing mechanism and pathway could be much different and hard to predict. Thus, we designed a fluorescence probe consisting 2-(3,5,5-trimethylcyclohex-2-en-1-ylidene)malononitrile as the electron withdrawing group and thienocoumarin as fluorophore in order to investigate the possible superiority in designing related optical sensors. In our research, it is interesting to find that our probe has the different properties compared with the similar reported probe bearing the coumarin fluorophore. The novel fluorescent probe (CSO–CN) was demonstrated to be able to detect HSO 3 − ions and changes in viscosity with a good resistance to oxidizers. The probe offers high sensitivity (LOD = 0.149 μM) for detecting HSO 3 − via the Michael addition reaction. It also enables fluorescence emission at 483 nm and the tracking of viscosity alternation by impeding the twisted intramolecular charge transfer (TICT) mechanism. Besides, the dual-functional probe has effectively been utilized to monitor HSO 3 − level in living cells, zebrafish and real food samples. [Display omitted] • Thienocoumarin based fluorescence probes that could specific detect bisulfite and viscosity. • Rapid, highly sensitive and highly selective detections in aqueous solutions. • Probe is oxidizer-resistant. • Probe can be used for imaging bisulfite in biosystems and real foods. [ABSTRACT FROM AUTHOR]

Bisulfite is a food additive with preservative and antioxidant properties; however, excessive use can severely damage nutritional compounds in food, reducing nutritional value. Moreover, it can lead to the development of sensitivities, asthma, localized heart anemia, and lung cancer. Therefore, it is essential to establish a simple, innovative, fast, and reliable method for bisulfite identification in foodstuffs. In this research, a novel fluorescence method based on manganese oxide nanosheets and carbon dots is designed for bisulfite detection in food samples. Initially, manganese oxide nanosheets were synthesized via a bottom-up approach, and carbon dots are produced using a hydrothermal synthesis method. The manganese oxide nanosheets oxidize tetramethyl benzidine, quenching the fluorescence emission of carbon dots. In the presence of bisulfite, oxidized tetramethyl benzidine is reduced, leading to the recovery of carbon dot fluorescence emission. Thus, bisulfite could be identified through the fluorescence signal of carbon dots. The linear range of the method varies from 0.2 to 2.5 mg L−1, with a detection limit of 0.06 mg L−1. Additionally, the developed method exhibits a rapid response time (< 30 s), good sensitivity, and selectivity. The method is applied to measure bisulfite in food samples such as water, vinegar, sugar, and macaroni, showing relative recovery between 90 % and 106 %, and a relative standard deviation of less than 5 %. These results demonstrate the successful performance of this method compared to previous similar approaches. • A fluorescence method based on manganese oxide nanosheets/carbon dots was designed. • The MnO 2 nanosheets oxidize tetramethyl benzidine, quenching the CDs emission. • Bisulfite could be identified through the fluorescence signal of carbon dots. • Bisulfite in food samples such as water, vinegar, sugar, and macaroni was measured. [ABSTRACT FROM AUTHOR]

Bisulfite (HSO 3 −) serves as a bleaching agent, antioxidant, antimicrobial, and regulator of enzymatic reactions in biosystem. However, abnormal levels of bisulfite can be detrimental to health. Hypochlorous acid (HOCl), which acts as bioactive small molecules, is crucial for maintaining normal biological functions in living organisms. Disruption of its equilibrium can lead to oxidative stress and various diseases. Therefore, it's essential to monitor the fluctuations of HOCl and HSO 3 − at cellular and in vivo levels to study their physiological and pathological functions. This study constructed a novel NIR bifunctional colorimetric fluorescent probe using thienocoumarin-indanedione structures to identify hypochlorite (ClO−) and bisulfite (HSO 3 −). By using CSO-IO to recognize HSO 3 − and HOCl, two distinct products were generated, displaying green and blue fluorescence, respectively. This property effectively allows for the simultaneous dual-functional detection of HSO 3 − (LOD: 113 nM) and HOCl (LOD: 43 nM). In this work, the biocompatible molecule CSO-IO has been effectively designed to detect HOCl/HSO 3 − in living cells and zebrafish. As a result, the dual-functional fluorescent probe has the potential to be utilized as a molecular tool to detect HSO 3 − derived compounds and HOCl simultaneously within the complex biological system. [Display omitted] • A NIR fluorescence probe that specific detect bisulfite and hypochlorous acid. • Rapid, highly sensitive and highly selective detections in aqueous solutions. • Probe can be used for monitoring bisulfite and HOCl level in biosystems. [ABSTRACT FROM AUTHOR]

Background: DNA methylation, the most common epigenetic modification, is defined as the removal or addition of methyl groups to cytosine bases. Studying DNA methylation provides insight into the regulation of gene expression, transposon mobility, genomic stability, and genomic imprinting. Whole-genome DNA methylation profiling (WGDM) is a powerful tool to find DNA methylation. This technique combines standard whole-genome sequencing methodology ( e.g., Illumina high-throughput sequencing) with additional steps where unmethylated cytosine is converted to uracil. However, factors such as low cytosine conversion efficiency and inadequate DNA recovery during sample preparation oftentimes render poor-quality data. It is therefore imperative to benchmark sample preparation protocols to increase sequencing data quality and reduce false positives in methylation detection. Methods: A survey analysis was performed to investigate the efficiency of the following commercially available cytosine conversion kits when coupled with the NEBNext® Ultra™ DNA Library Prep Kit for Illumina (NEB): Zymo Research EZ DNA Methylation™ kit (hereafter known as Zymo Conversion kit), QIAGEN EpiTect Bisulfite kit (hereafter known as QIAGEN Conversion kit), and NEBNext® Enzymatic Methyl-seq Conversion Module (hereafter known as NEB EM-seq kit). Input DNA was derived from soybean ( Glycine max [L.] Merrill) leaf tissue. Results: Of those tested, the QIAGEN Conversion kit provided the best sample recovery and the highest number of sequencing reads, whereas the Zymo Conversion kit had the best cytosine conversion efficiency and the least duplication. The sequence library obtained with the NEB EM-seq kit had the highest mapping efficiency (percentage of reads mapped to the genome). The data quality (defined by Phred score) and methylated cytosine call were similar between kits. Conclusions: This study offers the groundwork for selecting an effective DNA methylation detection kit for crop genome research.

Bisulfite (HSO3−) and sulfite (SO32−) compounds play key roles in numerous geochemical and biochemical processes extending from the atmosphere to the subseafloor biosphere. Despite decades of spectroscopic investigations, the molecular composition of HSO3− in solution remains uncertain and, thus, the role of bisulfite in (bio)chemical and isotope fractionation processes is unclear. We report new experimental estimates for the bisulfite isomer quotient (Qi = [(HO)SO2−]/[(HS)O3−]; [] = concentration) as a function of temperature from the interpretation of Raman spectra collected from aqueous NaHSO3 solutions contained in fused silica capsules. In pure NaHSO3 solutions (1Na+:1HSO3−, stoichiometric) over [NaHSO3] = 0.2–0.4 m (moles/kg H2O), the following relationship is obtained: ln(Qi)=[formula ommited]-1.9642(±0.1081),where T = 278–358 K (5–85 °C) (based on 50 determinations; additional significant figures are provided to avoid rounding errors). This relationship suggests that the minor isomer, (HS)O3−, may comprise 23–38% (±3%) of the mole fraction of HSO3− over 5–85 °C, respectively, which is higher in relative abundance than has generally been understood previously. We additionally provide estimates for Qi in NaHSO3 solutions containing a total ionic strength of µ = 1.0 m (0.2 m NaHSO3 + 0.8 m NaCl) and different pH (3.3–4.5), but do not appear to resolve any significant differences in Qi as a function of these additional variables. These new values of Qi are employed to re-assess the bulk sulfur isotope fractionations among bisulfite and other S(IV) compounds as a function of temperature, which appear to be highly dependent on the amount of (HS)O3− present. Our new constraints on the bisulfite isomer quotient may allow for a detailed assessment of the molecular composition and isotope mass balance of S(IV) solutions containing HSO3−, and may be useful in the further investigation of the mechanisms and isotope fractionations associated with a number of processes that involve bisulfite compounds. These may include the intracellular enzymatic transformations of sulfite and bisulfite compounds that occur as part of dissimilatory sulfate reduction, which is a major and geologically important form of anaerobic respiration.

Bisulfite (HSO3−) and sulfite (SO32−) compounds play key roles in numerous geochemical and biochemical processes extending from the atmosphere to the subseafloor biosphere. Despite decades of spectroscopic investigations, the molecular composition of HSO3− in solution remains uncertain and, thus, the role of bisulfite in (bio)chemical and isotope fractionation processes is unclear. We report new experimental estimates for the bisulfite isomer quotient (Qi = [(HO)SO2−]/[(HS)O3−]; [] = concentration) as a function of temperature from the interpretation of Raman spectra collected from aqueous NaHSO3 solutions contained in fused silica capsules. In pure NaHSO3 solutions (1Na+:1HSO3−, stoichiometric) over [NaHSO3] = 0.2–0.4 m (moles/kg H2O), the following relationship is obtained: ln(Qi)=[formula ommited]-1.9642(±0.1081),where T = 278–358 K (5–85 °C) (based on 50 determinations; additional significant figures are provided to avoid rounding errors). This relationship suggests that the minor isomer, (HS)O3−, may comprise 23–38% (±3%) of the mole fraction of HSO3− over 5–85 °C, respectively, which is higher in relative abundance than has generally been understood previously. We additionally provide estimates for Qi in NaHSO3 solutions containing a total ionic strength of µ = 1.0 m (0.2 m NaHSO3 + 0.8 m NaCl) and different pH (3.3–4.5), but do not appear to resolve any significant differences in Qi as a function of these additional variables. These new values of Qi are employed to re-assess the bulk sulfur isotope fractionations among bisulfite and other S(IV) compounds as a function of temperature, which appear to be highly dependent on the amount of (HS)O3− present. Our new constraints on the bisulfite isomer quotient may allow for a detailed assessment of the molecular composition and isotope mass balance of S(IV) solutions containing HSO3−, and may be useful in the further investigation of the mechanisms and isotope fractionations associated with a number of processes that involve bisulfite compounds. These may include the intracellular enzymatic transformations of sulfite and bisulfite compounds that occur as part of dissimilatory sulfate reduction, which is a major and geologically important form of anaerobic respiration.

• A near-infrared (NIR) emitted fluorescent probe for HSO 3 − has been developed. • SZY has the advantages of large Stokes shift, high water solubility, reliability in broad pH range, fast response time and low cytotoxicity. • The fluorescent imaging function of SZY for HSO 3 − tracking in live adult zebrafish and nude mouse has been successfully realized. • Semi-quantitative analysis of HSO 3 − levels in four food samples has been realized by "naked-eye" using SZY. Bisulfite (HSO 3 –) has been widely used as an important food additive in daily life. Furthermore, a normal amount of HSO 3 – plays a significant role in biological systems. However, excessive intake of HSO 3 – will lead to a variety of diseases. Therefore, it is of great significance to develop an efficient fluorescent probe that can be used for detection of HSO 3 – in biological systems and food samples. In this work, a near-infrared (NIR) emitted fluorescent probe (SZY) based on hemicyanine dye was successfully synthesized and applied to detect HSO 3 – in several food samples and live animals. The proposed nucleophilic addition sensing mechanism of SZY towards HSO 3 – has been confirmed by 1H NMR titration, high resolution mass spectrometry (HR-MS) and density functional theory (DFT) theoretical computation. The HSO 3 –-induced nucleophilic reaction with α,β-unsaturated C C binding of SZY results in the dramatic decline of the UV–vis absorption and remarkable quenching of the fluorescence emission. SZY features the advantages of near infrared emission (centered at 720 nm), high water solubility (in 98% aqueous solution), fast response time (50 s), large Stokes shift (244 nm) and low cytotoxicity. The probe SZY was successfully applied to image of HSO 3 – in live nude mouse and adult zebrafish. Semi-quantitatively analyzing the HSO 3 − level by "naked eye" in several food samples including canned fruit, white wine, white sugar and jasmine tea drinks has been realized by the colorimetric method. [ABSTRACT FROM AUTHOR]

DNA methylation is a fundamental epigenetic process and have a critical role in many biological processes. The study of DNA methylation at a large scale of genomic levels is widely conducted by several techniques that are next-generation sequencing (NGS)-based methods. Methylome data revealed by DNA methylation next-generation sequencing (mNGS), should be always verified by another technique which they usually have a high cost. In this study, we offered a low-cost approach to corroborate the mNGS data. In this regard, mNGS was performed on 6 colorectal cancer (case group) and 6 healthy individual colon tissue (control group) samples. An R-script detected differentially methylated regions (DMRs), was further validated by high resolution melting (MS-HRM) analysis. After analyzing the data, the algorithm found 194 DMRs. Two locations with the highest level of methylation difference were verified by MS-HRM, which their results were in accordance with the mNGS. Therefore, in the present study, we suggested MS-HRM as a simple, accurate and low-cost method, useful for confirming methylation sequencing results. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel fluorescent probe for highly specific and visible detecting hydrogen sulfide and bisulfite was developed. • The probe displayed significance dual-channel spectral behavior for hydrogen sulfide and bisulfite detection. • The probe was made into portable test strips for detecting hydrogen sulfide and bisulfite. A novel fluorescent probe was developed for simultaneously detection of hydrogen sulfide and bisulfite. The probe underwent remarkable turn on fluorescence response and significantly different UV–vis spectral changes in the presence of hydrogen sulfide or bisulfite with different response rates. As a result, this probe could be a potential candidate for imaging of hydrogen sulfide and bisulfite in vivo. [ABSTRACT FROM AUTHOR]

We present theoretical calculations for all three isotope ratios of sulfur (33S/32S, 34S/32S, 36S/32S) at the B3LYP/6-31+G(d,p) level of theory for aqueous sulfur compounds modeled in 30–40H2O clusters spanning the range of sulfur oxidation state (Sn, n = −2 to +6) for estimating equilibrium fractionation factors in aqueous systems. Computed 34β values based on major isotope (34S/32S) reduced partition function ratios (RPFRs) scale to a first order with sulfur oxidation state and coordination, where 34β generally increase with higher oxidation state and increasing coordination of the sulfur atom. Exponents defining mass dependent relationships based on β values (x/34κ = ln(xβ)/ln(34β), x = 33 or 36) conform to tight ranges over a wide range of temperature for all aqueous compounds (33/34κ ≈ 0.5148–0.5159, 36/34κ ≈ 1.89–1.90 from T ⩾ 0 °C). The exponents converge near a singular value for all compounds at the high temperature limit (33/34κT→∞ = 0.51587 ± 0.00003 and 36/34 κT→∞ = 1.8905 ± 0.0002; 1 s.d. of all computed compounds), and typically follow trends based on oxidation state and coordination similar to those seen in 34β values at lower temperatures. Theoretical equilibrium fractionation factors computed from these β-values are compared to experimental constraints for HSO3−T(aq)/SO2(g, aq), SO2(aq)/SO2(g), H2S(aq)/H2S(g), H2S(aq)/HS−(aq), SO42−(aq)/H2ST(aq), S2O32−(aq) (intramolecular), and S2O32−(aq)/H2ST(aq), and generally agree within a reasonable estimation of uncertainties. We make predictions of fractionation factors where other constraints are unavailable. Isotope partitioning of the isomers of protonated compounds in the sulfite and sulfoxylate systems depend strongly on whether protons are bound to either sulfur or oxygen atoms. The magnitude of the HSO3−T/SO32− major isotope (34S/32S) fractionation factor is predicted to increase with temperature from 0 to 70 °C due to the combined effects of the large magnitude (HS)O3−/SO32− fractionation factor (1000ln34α(HS)bisulfite-sulfite = 19.9‰, 25 °C) relative to the (HO)SO2−/SO32− fractionation factor (1000ln34α(HO)bisulfite–sulfite = −2.2‰, 25 °C), and the increased stability of the (HS)O3− isomer with increasing temperature. We argue that isomerization phenomenon should be considered in models of the sulfur cycle, including models that describe the overall sulfur isotope fractionations associated with microbial metabolism (e.g., microbial sulfate reduction).

Abstract Background The combination of the bisulfite treatment and the next-generation sequencing is an important method for methylation analysis, and aligning the bisulfite-treated reads (BS-reads) is the critical step for the downstream applications. As bisulfite treatment reduces the complexity of the sequences, a large portion of BS-reads might be aligned to multiple locations of the reference genome ambiguously, called multireads. These multireads cannot be employed in the downstream applications since they are likely to introduce artifacts. To identify the best mapping location of each multiread, existing Bayesian-based methods calculate the probability of the read at each position by considering how does it overlap with unique mapped reads. However, $$\sim 25$$ ∼ 25 % of multireads are not overlapped with any unique reads, which are unresolvable for existing method. Results Here we propose a novel method (EM-MUL) that not only rescues multireads overlapped with unique reads, but also uses the overall coverage and accurate base-level alignment to resolve multireads that cannot be handled by current methods. We benchmark our method on both simulated datasets and real datasets. Experimental results show that it is able to align more than 80% of multireads to the best mapping position with very high accuracy. Conclusions EM-MUL is an effective method designed to accurately determine the best mapping position of multireads in BS-reads. For the downstream applications, it is useful to improve the methylation resolution on the repetitive regions of genome. EM-MUL is free available at https://github.com/lmylynn/EM-MUL.

Bisulfite (HSO3−) is associated with many physiological processes in living systems. High concentration of HSO3− may lead to many diseases. Herein, a simple levulinate‐based colorimetric fluorescent probe for HSO3− detection was designed and synthesized. The probe showed high selectivity for HSO3− detection with color changes from light pink to deep pink. Under the optimal test conditions, there is a good linear relationship between fluorescence intensity and concentrations of HSO3− in the range of 0–50 μM with detection limit of 1.04 nM. In addition, the probe was successfully applied to monitor HSO3− in living cells and zebrafish, which proved that the probe can be used to detect HSO3− in living systems. Introduction [ABSTRACT FROM AUTHOR]

Background: In mammals, modifications to cytosine bases, particularly in cytosine-guanine (CpG) dinucleotide contexts, play a major role in shaping the epigenome. The canonical epigenetic mark is 5-methylcytosine (5mC), but oxidized versions of 5mC, including 5-hydroxymethylcytosine (5hmC), are now known to be important players in epigenomic dynamics. Understanding the functional role of these modifications in gene regulation, normal development, and pathological conditions requires the ability to localize these modifications in genomic DNA. The classical approach for sequencing cytosine modifications has involved differential deamination via the chemical sodium bisulfite; however, bisulfite is destructive, limiting its utility in important biological or clinical settings where detection of low frequency populations is critical. Additionally, bisulfite fails to resolve 5mC from 5hmC. Scope of review: To summarize how enzymatic rather than chemical approaches can be leveraged to localize and resolve different cytosine modifications in a non-destructive manner. Major conclusions: Nature offers a suite of enzymes with biological roles in cytosine modification in organisms spanning from bacteriophages to mammals. These enzymatic activities include methylation by DNA methyltransferases, oxidation of 5mC by TET family enzymes, hypermodification of 5hmC by glucosyltransferases, and the generation of transition mutations from cytosine to uracil by DNA deaminases. Here, we describe how insights into the natural reactivities of these DNA-modifying enzymes can be leveraged to convert them into powerful biotechnological tools. Application of these enzymes in sequencing can be accomplished by relying on their natural activity, exploiting their ability to discriminate between cytosine modification states, reacting them with functionalized substrate analogs to introduce chemical handles, or engineering the DNA-modifying enzymes to take on new reactivities. We describe how these enzymatic reactions have been combined and permuted to localize DNA modifications with high specificity and without the destructive limitations posed by chemical methods for epigenetic sequencing.

Based on coumarin structure, two fluorescent probes (L1 and L2) were constructed for specific detection of bisulfite (HSO3−) and hypochlorite (ClO−). Electron deficient carbon–carbon double bond and acidic proton were introduced to regulate the performance of two fluorescent molecules. Both L1 and L2 displayed high selectivity and sensitivity, low detection limit (28.2, 52.0 nM), fast response time and visible color change after addition of HSO3− or ClO−. Different techniques including 1H NMR analysis, high-resolution mass spectrometry and density functional theory calculations were used to confirm our conception and to get insight into the interaction of receptors with anions. Furthermore, probe L1 was successfully applied to monitor the level of HSO3− in sugar samples and real water samples. [ABSTRACT FROM AUTHOR]

Abstract Background Bisulfite addition is an important H2 photoproduction strategy that removes O2 and activates hydrogenase. The pH values of cell cultures can change the ratio of bisulfite to sulfite, which may affect H2 photoproduction. However, little is known regarding the pH effect of bisulfite addition on H2 photoproduction and relevant underlying mechanism. Results Here, changes in H2 photoproduction with different initial extracellular pH values showed a parabolic distribution and a pH of 8.0 is an optimal value for H2 photoproduction in Chlamydomonas reinhardtii cells treated with bisulfite. Compared to the growth pH (pH 7.3), increased photoproduction of H2 at this optimal pH was primarily caused by a relatively high residual activity of photosystem II (PSII), which provides a relatively plentiful source of electrons for H2 photoproduction. Such increased H2 photoproduction was most likely a result of decreased the ratio of bisulfite to sulfite, consistent with the result that the toxicity of bisulfite on PSII was much more than that of sulfite. This possibility was corroborated by the result that treatment with a combination of 7 mM bisulfite and 6 mM sulfite further enhanced H2 photoproduction compared with 13 mM bisulfite alone. Conclusions Collectively, our findings provide novel mechanistic insights into pH-dependent H2 photoproduction in C. reinhardtii cells treated with bisulfite, and demonstrate that sulfite addition is another important strategy for H2 photoproduction, just like bisulfite addition.

We developed a simplified workflow of gDNA extraction from ejaculated bovine sperm using a low total number of sperm and a short time frame that yields high-quality DNA suitable for downstream methylation and genome analyses. These techniques have broad implications in human biomedical sciences and agriculture, including clinical diagnoses of infertility, the identification of single-nucleotide polymorphisms and aberrant methylation patterns that can impact fertility, lower embryo development and contribute to heritable disease. The methods described here provide a reliable, simplistic approach for analyzing both the genomic and epigenomic status of whole sperm ejaculates that can be adapted for laboratory diagnostics, clinical reproductive practice and basic research.

The detection of changes in the reactive oxygen species (ROS)/reactive sulfur species (RSS) couple is important for studying the cellular redox state. Herein, we developed a 1,8‐naphthalimide‐based fluorescence probe (NI) for the reversible detection of bisulfite (HSO3−) and hydrogen peroxide (H2O2) in vitro and in vivo. NI has been designed with a reactive ethylene unit which specifically reacts with HSO3− by a Michael addition reaction mechanism, resulting in the quenching of yellow fluorescence at 580 nm and the appearing of green fluorescence at 510 nm upon excitation at 500 nm and 430 nm, respectively. The addition product (NI−HSO3) could be specifically oxidized to form the original C=C bond of NI, recovering the fluorescence emission and color. The detection limits of NI for HSO3− and NI−HSO3 for H2O2 were calculated to be 2.05 μM and 4.23 μM, respectively. The reversible fluorescence response of NI towards HSO3−/H2O2 couple can be repeated for at least five times. NI is reliable at a broad pH range (pH 3.0–11.5) and features outstanding selectivity, which enabled its practical applications in biological and food samples. Monitoring the reversible and dynamic inter‐conversion between HSO3− and H2O2in vitro and in vivo has been verified by fluorescence imaging in live HeLa cells, adult zebrafish and nude mice. Moreover, NI has been successfully applied to detect of HSO3− levels in food samples. [ABSTRACT FROM AUTHOR]

Here in, a system of Co 3 O 4 /CoO catalyst activated with the aid of bisulfite (NaHSO 3) was established for the decomposition of methylene blue (MB). The Co 3 O 4 /CoO material was designed by a two-step uniform precipitation and calcination method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) spectroscopy to detect the crystallinity, morphology, magnetic ability, element valence and the different types of free radicals, respectively. The efficient degradation of MB relies on the synergistic effect between the Co 3 O 4 /CoO catalyst and bisulfite (NaHSO 3) to generate some strongly oxidizing radicals, which could achieve a MB degradation rate of 90.7% within 40 min using this novel system. Additionally, the ferromagnetic property of Co 3 O 4 /CoO catalyst is expected to supply an excellent magnetic separation ability to help separate the solid catalyst from the aqueous solution. The novel catalyst system of Co 3 O 4 /CoO/NaHSO 3 may serve as a promising new system for wastewater treatment. • Co 3 O 4 /CoO was synthesized to activate NaHSO 3 for fast methylene blue degradation. • Vibrating sample magnetometer showed the magnetic property of Co 3 O 4 /CoO. • Co 3 O 4 /CoO composite was easily separated from solution by an external magnet. • SO 4.•- and •OH were confirmed as active radicals in the Co 3 O 4 /CoO/NaHSO 3 system [ABSTRACT FROM AUTHOR]

This work presented a FRET-ICT based fluorescent probe (named NTC) composed of coumarin-benzothiazole as the acceptor and 4-nitrobenzo[ c ][1,2,5] oxadiazole (NBD) as the donor for the detection of SO 2 derivatives in NIR. Probe NTC possessed superior performance including selectivity, quickly response toward SO 3 2−/HSO 3 − and high energy transfer efficiency (94 %). The test strips provided a simple and effective tool in detecting the presence of bisulfite. Besides, NTC was applied to test the sulfur dioxide derivatives in food samples and cells. [Display omitted] • A NIR ratiometric fluorescent probe NTC was developed to detect sulfur dioxide derivatives. • NTC had a large Stokes shift of 150 nm and 94 % energy transfer efficiency. • NTC possessed good selectivity and sensitivity toward sulfur dioxide derivatives. • NTC was applied to detect sulfur dioxide derivatives in test strips, food samples and cell imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel fluorescent probe compatible with GDME device was prepared. • A GDME-FL method was developed to detect HSO 3 −. • The method has been successfully applied for food analysis. • The Lens cleaning paper were first used for imaging research. • The probe shows high response speed, selectivity and sensitivity toward free bisulfite/sulfite anions. Excessive residues of sulfite (SO 3 2−) have negative effects on human health; thus, it is important to monitor SO 3 2− levels in food samples and living cells. In this study, a novel fluorescent probe (E)-4-(2-(2-(7-(diethylamino)-2-oxo-2H-chromen-3-yl) vinyl) −1,1-dimethyl-1H-benzo[e]indol-3-ium-3-yl) butane-1-sulfonate (probe 1) was prepared. This probe was based on a conjugated coumarin–benzindolium system that was detected to exhibit high-response speed and selectivity and sensitivity towards free bisulfite/sulfite (HSO 3 −/SO 3 2−) anions. Probe 1 was also highly compatible with gas-diffusion microextraction (GDME) because of its good water solubility, reaction rapidness and ratiometric signal response. Extraction and detection tasks could be completed within 30 min under the selected experimental conditions. The developed GDME-FL method showed adequate limits of detection (4.9 μM) and quantification (16.2 μM) for food analysis. The applications of this method for the detection of free HSO 3 − in product samples were investigated thoroughly. In addition, we successfully applied probe 1 to image lens cleaning paper, onion, Daphnia magna and HeLa cells. Therefore, probe 1 has a promising application potential for measuring the HSO 3 −/SO 3 2− content of real food samples. [ABSTRACT FROM AUTHOR]

• Reduction of p-nitrophenol by ZVI was greatly enhanced by bisulfite under anoxic condition. • Bisulfite could dissolve some iron oxide on the ZVI surface and accelerate the reduction of Fe(III) to Fe(II). • Bisulfite can be used as a cost-effective and environmental-friendly additive to enhance the reduction activity of ZVI. Zero-valent iron (ZVI) is widely used in the field of wastewater treatment and groundwater remediation, but it suffers from low reactivity due to the surface passivation layer. In the present work, bisulfite was used as an additive to enhance the reduction activity of ZVI under anoxic conditions. It was found that the reaction kinetic constant of p-nitrophenol reduction in ZVI/bisulfite process was approximately 132 times higher than that by ZVI alone. Bisulfite could dissolve and reduce some iron oxide on the ZVI surface, resulting in the exposure of more active sites like Fe0 and Fe(II) for p-nitrophenol reduction through direct electron transfer. Common substances in water had no effects on p-nitrophenol degradation by ZVI/bisulfite process, but phosphate suppressed ZVI corrosion seriously. This work provides a simple, cost-effective and environmental-friendly method to improve the reducing activity of ZVI under anoxic conditions. [ABSTRACT FROM AUTHOR]

Bisulfite (HSO3−) and biological thiols molecules, such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy), play important roles in organisms. Developing a fluorescent probe that can simultaneously detect and distinguish HSO3− and biological thiols is of great significance. In this study, ethyl(2E,4Z)-5-chloro-2-cyano-5-(7-(diethylamino)-2-oxo-2 H-chromen-3-yl)penta-2,4-dienoate (CCO) as a novel enhanced fluorescence probe was synthesized by integrating coumarin derivatives and ethyl cyanoacetate, which can simultaneous detection and discrimination of hydrogen bisulfite anions and glutathione. The sensing mechanism was elucidated through spectral analysis and some control experiments. In weakly alkaline environments, the probe not only has good selectivity for HSO3− and GSH, but also has a lower detection limits of 0.0179 µM and 0.2034 µM. The probe exhibited fuorescent turn-on for distinguishing with 296 and 28 fold the fluorescent intensity increase at 486 and 505 nm, respectively, through diferent excitation wavelengths. This provides a new method for simultaneous detection and discrimination of HSO3− and biological thiol cell levels and further applications. [ABSTRACT FROM AUTHOR]

Maintaining redox homeostasis in organisms plays a crucial role in human life and health, and changes in the levels of SO 2 and H 2 O 2 , as typical representative substances of reductants and oxidants, directly affects intracellular redox homeostasis. Hence, it is necessary to manufacture fluorescent probes that can detect HSO 3 − and H 2 O 2. In this work, a benzopyrylium salt containing benzothiazole derived fluorescent probe HBTO-H with dual properties of aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) has been developed. The probe displays rapid and reversible test of HSO 3 − and H 2 O 2 in DMF/Tris (v:v = 2:8, pH = 7.3, Tris 10 mM) mixed solvent with high selectivity, good anti-interference ability and a wide applicable pH range (6–11). The detection limits of HBTO-H for HSO 3 − and H 2 O 2 are 0.187 μM and 0.152 μM, respectively. The response mechanisms of HBTO-H toward HSO 3 − and H 2 O 2 have been demonstrated to be Michael addition reaction and its retro-reaction based on 1H NMR and HRMS analyses. In addition, HBTO-H has been successfully applied to check HSO 3 − in sugar and wine specimens. Moreover, HBTO-H was proved to be mitochondria-targetable and can alternately detect exogenous HSO 3 − and H 2 O 2 in MCF-7 cells, which is desired to be applied to trace HSO 3 − in organisms in the future. [Display omitted] • A simple "AIE + ESIPT" mechanism-based fluorescent probe HBTO-H has been developed. • HBTO-H displays rapid (time <1 min) and reversible detection of HSO 3 − and H 2 O 2. • HBTO-H has high selectivity and anti-interference along with low detection limit. • HBTO-H can be applied to detect HSO 3 − in food samples. • HBTO-H possesses mitochondria-targeting function. [ABSTRACT FROM AUTHOR]

Background: The combination of the bisulfite treatment and the next-generation sequencing is an important method for methylation analysis, and aligning the bisulfite-treated reads (BS-reads) is the critical step for the downstream applications. As bisulfite treatment reduces the complexity of the sequences, a large portion of BS-reads might be aligned to multiple locations of the reference genome ambiguously, called multireads. These multireads cannot be employed in the downstream applications since they are likely to introduce artifacts. To identify the best mapping location of each multiread, existing Bayesian-based methods calculate the probability of the read at each position by considering how does it overlap with unique mapped reads. However, ∼ 25 % of multireads are not overlapped with any unique reads, which are unresolvable for existing method. Results: Here we propose a novel method (EM-MUL) that not only rescues multireads overlapped with unique reads, but also uses the overall coverage and accurate base-level alignment to resolve multireads that cannot be handled by current methods. We benchmark our method on both simulated datasets and real datasets. Experimental results show that it is able to align more than 80% of multireads to the best mapping position with very high accuracy. Conclusions: EM-MUL is an effective method designed to accurately determine the best mapping position of multireads in BS-reads. For the downstream applications, it is useful to improve the methylation resolution on the repetitive regions of genome. EM-MUL is free available at https://github.com/lmylynn/EM-MUL. [ABSTRACT FROM AUTHOR]

By connecting 1,8-naphthalimide and indole sulfonate, a ratio fluorescent probe capable of differential detection of hydrogen sulfite and hypochlorite was synthesized for the first time. It was able to achieve the qualitative detection of HSO3− and ClO− with high sensitivity and selectivity, respectively. It provides a multi-purpose probe and is based on different emission channels without mutual interference. The probe has the advantages of larger Stokes shift (ClO−: 115 nm, HSO3−: 88 nm), longer λem (ClO−: 515 nm, HSO3−: 548 nm) and better water solubility (DMF/PBS = 1:99, v/v). In addition, the probe is a ratio fluorescence probe, which can detect fluorescence intensity with two different emission waves. It provides internal self-calibration, reduces interference from the background and increases detection accuracy. In vitro cytotoxicity and imaging experiments show that the probe can effectively perform the detection of exogenous HSO3− and ClO− in cells. It can also achieve the detection of HSO3− and ClO− in the plasma environment. Because the probe can detect endogenous ClO−, it also has a good prospect for biological application in identifying tumor cells. [ABSTRACT FROM AUTHOR]

With the booming development of food manufacturing, developing ideal analytical tools to precisely quantify food additives is highly sought after in the food science field. Herein, a new series of quinoline-derived multifunctional fluorescent probes has been synthesized. Bearing double reactive sites, these compounds display fluorescence response toward both bisulfite (HSO 3 - ) and hypochlorous acid (HClO). Among these compact structures, compound ethyl-2-cyano-3-(6-(methylthio)quinolin-2-yl)acrylate ( QTE ) was screened out. Probe QTE not only shows ratiometric variation toward HSO 3 - with little cross talk but also performs turn-off signal toward HClO. In addition, probe QTE has been utilized for bioimaging of HClO in living cells. Furthermore, the HSO 3 - content in dried food samples has been appraised by QTE with satisfactory results. Meanwhile, relying on the apparent chromaticity change, a flexible dark-box device has been elaborated for chromatic analysis, promoting visualization of HSO 3 - in the field.

A ZnMn2O4 catalyst has been synthesized via a sucrose-aided combustion method and characterized by various analytical techniques. It is composed of numerous nanoparticles (15–110 nm) assembled into a porous structure with a specific surface area (SSA) of 19.1 m2·g−1. Its catalytic activity has been investigated for the degradation of orange II dye using three different systems, i.e., the photocatalysis system with visible light, the chemocatalysis system with bisulfite, and the photochemical catalysis system with both visible light and bisulfite. The last system exhibits the maximum degradation efficiency of 90%, much higher than the photocatalysis system (15%) and the chemocatalysis system (67%). The recycling experiments indicate that the ZnMn2O4 catalyst has high stability and reusability and is thus a green and eximious catalyst. Furthermore, the potential degradation mechanisms applicable to the three systems are discussed with relevant theoretical analysis and scavenging experiments for radicals. The active species such as Mn(III), O2•−, h+, eaq−, SO4•− and HO• are proposed to be responsible for the excellent degradation results in the photo-chemical catalysis system with the ZnMn2O4 catalyst. [ABSTRACT FROM AUTHOR]

More than 60 years have passed since UCLA first announced the development of an innovative asymmetric cellulose acetate reverse osmosis (RO) membrane in 1960. This innovation opened a gate to use RO for commercial use. RO is now ubiquitous in water treatment and has been used for various applications, including seawater desalination, municipal water treatment, wastewater reuse, ultra-pure water (UPW) production, and industrial process waters, etc. RO is a highly integrated system consisting of a series of unit processes: (1) intake system, (2) pretreatment, (3) RO system, (4) post-treatment, and (5) effluent treatment and discharge system. In each step, a variety of chemicals are used. Among those, sulfites (sodium bisulfite and sodium metabisulfite) have played significant roles in RO, such as dechlorination, preservatives, shock treatment, and sanitization, etc. Sulfites especially became necessary as dechlorinating agents because polyamide hollow-fiber and aromatic thin-film composite RO membranes developed in the late 1960s and 1970s were less tolerable with residual chlorine. In this review, key applications of sulfites are explained in detail. Furthermore, as it is reported that sulfites have some adverse effects on RO membranes and processes, such phenomena will be clarified. In particular, the following two are significant concerns using sulfites: RO membrane oxidation catalyzed by heavy metals and a trigger of biofouling. This review sheds light on the mechanism of membrane oxidation and triggering biofouling by sulfites. Some countermeasures are also introduced to alleviate such problems.

Two unprecedented solid phases involving the 3,7-bis(dimethylamino)phenothiazin-5-ium cation, i.e. methylene blue (MB+), have been obtained and structurally characterized. In the crystals of 3,7-bis(dimethylamino)phenothiazin-5-ium chloride dihydrate, C16H18N3S+·Cl−·2H2O (I) and 3,7-bis(dimethylamino)phenothiazinium bisulfite, C16H18N3S+·HSO4− (II), the cationic dye molecules are planar and disposed in an antiparallel mode, showing π–π stacking interactions, with mean interplanar distances of 3.326 (4) and 3.550 (3) Å in (I) and (II), respectively. In compound (I), whose phase was found affected by merohedral twinning [BASF = 0.185 (3)], the presence of water molecules allows a network of hydrogen bonds involving MB+ as both a donor and an acceptor, whereas in compound (II), the homo-interaction of the anions causes an effective absence of classical hydrogen-bond donors. This substantial difference has important consequences for the stacking geometry and supramolecular interactions of the MB+ cations, which are analysed by Hirshfeld fingerprint plots and subsequently discussed.

Ionic liquids (ILs) have been reported to have an enhanced absorption capacity for SO2 compared to that of traditional molecular solvents. This work evaluated the effect of water content in a 1-butyl-3-methyl imidazolium chloride [bmim][Cl] solution on the absorption of a diluted gas stream under dynamic conditions in a packed-bed column and analyzing chemical changes by FT-IR spectroscopy. For aqueous IL solutions, the absorption behavior shown a first fast-chemical reaction related to the SO2–sulfite–bisulfite water equilibrium followed by physical absorption. The whole process is not limited by mass transfer. Conversely, in low water-content IL, the SO2 interacts directly with the cation and absorption capacity is highly improved. In this case, mass transport limitations were detected as a consequence of high viscosity. For diluted IL solutions, only partial isothermal desorption could be reached by changing the solution pH. No desorption is obtained for highly concentrated solutions. The water content has a positive effect in reducing mass transfer limitation; however, changes the mechanism of absorption and reduce the capture capacity. The chemistry involved in aqueous IL capture of SO2 seems to be analogous to amine-based technology; however, the non-volatility and thermal/chemical stability of the [bmim][Cl] allow minimize the generation of atmospheric and liquid phase pollutants during the absorption operation. [ABSTRACT FROM AUTHOR]

A new carbazole-based colorimetric and fluorescent probe CBB for the detection of bisulfite (HSO3−) has been developed via nucleophilic addition reaction. Probe CBB can detect HSO3− with excellent sensing properties including high selectivity and sensitivity, fast response (5 s). More importantly, probe CBB system not only can be applied to monitor HSO3− in environment with excellent solid properties based on test strips but also can be used for the detection of HSO3− in real-water samples with satisfactory results. [ABSTRACT FROM AUTHOR]

A reaction-based sensor (NAS-1) showed a high affinity and sensitivity to HSO3- via a nucleophilic addition reaction in the aqueous media, giving dual signals from absorption and emission spectra. NAS-1 was successfully applied in RK13 epithelial cells to detect HSO3- in a cellular environment. [ABSTRACT FROM AUTHOR]

A reaction-based sensor (NAS-1) showed a high affinity and sensitivity to HSO3- via a nucleophilic addition reaction in the aqueous media, giving dual signals from absorption and emission spectra. NAS-1 was successfully applied in RK13 epithelial cells to detect HSO3- in a cellular environment. [ABSTRACT FROM AUTHOR]

Background: Bisulfite addition is an important H2 photoproduction strategy that removes O2 and activates hydrogenase. The pH values of cell cultures can change the ratio of bisulfite to sulfite, which may affect H2 photoproduction. However, little is known regarding the pH effect of bisulfite addition on H2 photoproduction and relevant underlying mechanism. Results: Here, changes in H2 photoproduction with different initial extracellular pH values showed a parabolic distribution and a pH of 8.0 is an optimal value for H2 photoproduction in Chlamydomonas reinhardtii cells treated with bisulfite. Compared to the growth pH (pH 7.3), increased photoproduction of H2 at this optimal pH was primarily caused by a relatively high residual activity of photosystem II (PSII), which provides a relatively plentiful source of electrons for H2 photoproduction. Such increased H2 photoproduction was most likely a result of decreased the ratio of bisulfite to sulfite, consistent with the result that the toxicity of bisulfite on PSII was much more than that of sulfite. This possibility was corroborated by the result that treatment with a combination of 7 mM bisulfite and 6 mM sulfite further enhanced H2 photoproduction compared with 13 mM bisulfite alone. Conclusions: Collectively, our findings provide novel mechanistic insights into pH-dependent H2 photoproduction in C. reinhardtii cells treated with bisulfite, and demonstrate that sulfite addition is another important strategy for H2 photoproduction, just like bisulfite addition. [ABSTRACT FROM AUTHOR]

A two-photon fluorescent probe has been adopted for bisulfite based on an intramolecular charge transfer (ICT) mechanism. The fluorescence intensity of the probe decreased by 837 fold following treatment with HSO3− and the detection limit was 42 nM. This probe showed excellent properties such as high photostability, good two-photon properties, and large Stokes shifts. More importantly, this approach offers a rapid, highly selective, and sensitive method to determine HSO3− in buffer solutions and real samples. Furthermore, the probe was successfully used for two-photon fluorescence visualization of trace SO2 derivatives in biological systems. [ABSTRACT FROM AUTHOR]

Sulfur dioxide (SO 2) had been recognized as an environmental pollutant produced from industrial processes. SO 2 is water soluble and forms hydrated SO 2 (SO 2 ·H 2 O), bisulfite ion (HSO 3 −), and sulfite ion (SO 3 2−) upon dissolution in water. SO 2 could be also produced endogenously from sulfur-containing amino acids l -cysteine in mammals. Endogenous SO 2 can maintain the balance of biological sulfur and redox equilibrium in vivo , regulate blood insulin levels and reduce blood pressure. Excess intake of exogenous SO 2 can result in respiratory diseases, cardiovascular diseases and neurological disorders. As a result, fluorescent probes to detect HSO 3 −/SO 3 2− have attracted great attention in recent years. Herein, a general overview was provided with the aim to highlight the typical examples of the HSO 3 −/SO 3 2− fluorescent probes reported since 2010, especially those in the past five years. We have classified HSO 3 −/SO 3 2− fluorescent probes through different chemical reaction mechanisms and wish this review will give some help to the researchers in this field. Image 1 • 84 different reaction-based fluorescent probes for HSO 3 −/SO 3 2− have been summarized. • These fluorescent probes have been divided into helpful categories according to the chemical mechanism of detection. • The two tables and one figure in the end summarize the entire contents. • This review also provides interesting insights for future developments of fluorescent probes for HSO 3 −/SO 3 2−. [ABSTRACT FROM AUTHOR]