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Keratan sulfate (KS) is a proteoglycan that is widely expressed in the extracellular matrix of various tissue types, where it performs multiple biological functions. KS is the least understood proteoglycan, which in part is due to a lack of panels of well-defined KS oligosaccharides that are needed for structure-binding studies, as analytical standards, to examine substrate specificities of keratinases, and for drug development. Here, we report a biomimetic approach that makes it possible to install, in a regioselective manner, sulfates and fucosides on oligo- N -acetyllactosamine (LacNAc) chains to provide any structural element of KS by using specific enzyme modules. It is based on the observation that α1,3-fucosides, α2,6-sialosides and C-6 sulfation of galactose (Gal6S) are mutually exclusive and cannot occur on the same LacNAc moiety. As a result, the pattern of sulfation on galactosides can be controlled by installing α1,3-fucosides or α2,6-sialosides to temporarily block certain LacNAc moieties from sulfation by keratan sulfate galactose 6-sulfotransferase (CHST1). The patterns of α1,3-fucosylation and α2,6-sialylation can be controlled by exploiting the mutual exclusivity of these modifications, which in turn controls the sites of sulfation by CHST1. Late-stage treatment with a fucosidase or sialidase to remove blocking fucosides or sialosides provides selectively sulfated KS oligosaccharides. These treatments also unmasked specific galactosides for further modification by CHST1. To showcase the potential of the enzymatic strategy, we have prepared a range of poly-LacNAc derivatives having different patterns of fucosylation and sulfation and several N -glycans decorated by specific arrangements of sulfates.

Pseudomonas aeruginosa biofilms comprise three main polysaccharides: alginate, psl, and pel, which all imbue tolerance against exogenous antimicrobials. Nanoparticles (NPs) are an exciting new strategy to overcome the biofilm matrix for therapeutic delivery applications; however, zero existing FDA approvals for biofilm-specific NP formulations can be attributed to the complex interplay of physiochemical forces at the biofilm-NP interface. Here, we leverage a set of inducible, polysaccharide-specific, expressing isogenic P. aeruginosa mutants coupled with an assembled layer-by-layer NP (LbL NP) panel to characterize biofilm-NP interactions. When investigating these interactions using confocal microscopy, alginate-layered NPs associated more than dextran-sulfate-layered NPs with biofilms that had increased alginate production, including biofilms produced by mucoid P. aeruginosa isolates from people with cystic fibrosis. These differences were further confirmed in LbL NPs layered with polysaccharide- or hydrocarbon-based polymers with pendent carboxylate or sulfate functional groups. These data suggest carboxylated NP surfaces have enhanced interactions specifically with mucoid biofilms as compared to sulfated surfaces and lay the foundation for their inclusion as a design element for increasing biofilm-NP interactions and efficacious drug delivery.

The removal of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) using sulfate anion radical (SO 4 •- )-based advanced oxidation processes has gained considerable attention recently. However, immense uncertainties persist in technology transfer. Particularly, the impact of dichlorine radical (Cl 2 •- ) generation during SO 4 •- -mediated disinfection on ARB/ARGs removal remains unclear, despite the Cl 2 •- concentration reaching levels notably higher than those of SO 4 •- in certain SO 4 •- -based procedures applied to secondary effluents, hospital wastewaters, and marine waters. The experimental results of this study reveal a detrimental effect on the disinfection efficiency of tetracycline-resistant Escherichia coli (Tc-ARB) during SO 4 •- -mediated treatment owing to Cl 2 •- generation. Through a comparative investigation of the distinct inactivation mechanisms of Tc-ARB in the Cl 2 •- - and SO 4 •- -mediated disinfection processes, encompassing various perspectives, we confirm that Cl 2 •- is less effective in inducing cellular structural damage, perturbing cellular metabolic activity, disrupting antioxidant enzyme system, damaging genetic material, and inducing the viable but nonculturable state. Consequently, this diminishes the disinfection efficiency of SO 4 •- -mediated treatment owing to Cl 2 •- generation. Importantly, the results indicate that Cl 2 •- generation increases the potential risk associated with the dark reactivation of Tc-ARB and the vertical gene transfer process of tetracycline-resistant genes following SO 4 •- -mediated disinfection. This study underscores the undesired role of Cl 2 •- for ARB/ARGs removal during the SO 4 •- -mediated disinfection process.

Advanced oxidation processes (AOPs), such as hydroxyl radical (HO • )- and sulfate radical (SO 4 •- )-mediated oxidation, are attractive technologies used in water and wastewater treatments. To evaluate the treatment efficiencies of AOPs, monitoring the primary radicals (HO • and SO 4 •- ) as well as the secondary radicals generated from the reaction of HO • /SO 4 •- with water matrices is necessary. Therefore, we developed a novel chemical probe method to examine five key radicals simultaneously, including HO • , SO 4 •- , Cl • , Cl 2 •- , and CO 3 •- . Five probes, including nitrobenzene, para -chlorobenzoic acid, benzoic acid, 2,4,6-trimethylbenzoic acid, and 2,4,6-trimethylphenol, were selected in this study. Their bimolecular reaction rate constants with diverse radicals were first calibrated under the same conditions to minimize systematic errors. Three typical AOPs (UV/H 2 O 2 , UV/S 2 O 8 2- , and UV/HSO 5 - ) were tested to obtain the radical steady-state concentrations. The effects of dissolved organic matter, Br - , and the probe concentration were inspected. Our results suggest that the five-probe method can accurately measure radicals in the HO • - and SO 4 •- -mediated AOPs when the concentration of Br - and DOM are less than 4.0 μM and 15 mg C L -1 , respectively. Overall, the five-probe method is a practical and easily accessible method to determine multiple radicals simultaneously.

Biological sulfate reduction (BSR) represents a promising strategy for bioremediation of sulfate-rich waste streams, yet the impact of metabolic interactions on performance is largely unexplored. Here, genome-resolved metagenomics was used to characterize 17 microbial communities in reactors treating synthetic sulfate-contaminated solutions. Reactors were supplemented with lactate or acetate and a small amount of fermentable substrate. Of the 163 genomes representing all the abundant bacteria, 130 encode 321 NiFe and FeFe hydrogenases and all genomes of the 22 sulfate-reducing microorganisms (SRM) encode genes for H 2 uptake. We observed lactate oxidation solely in the first packed bed reactor zone, with propionate and acetate oxidation in the middle and predominantly acetate oxidation in the effluent zone. The energetics of these reactions are very different, yet sulfate reduction kinetics were unaffected by the type of electron donor available. We hypothesize that the comparable rates, despite the typically slow growth of SRM on acetate, are a result of the consumption of H 2 generated by fermentation. This is supported by the sustained performance of a predominantly acetate-supplemented stirred tank reactor dominated by diverse fermentative bacteria encoding FeFe hydrogenase genes and SRM capable of acetate and hydrogen consumption and CO 2 assimilation. Thus, addition of fermentable substrates to stimulate syntrophic relationships may improve the performance of BSR reactors supplemented with inexpensive acetate.

The pharmacokinetics (PK) of hydroxytyrosol and its metabolites were characterized following oral administration to Sprague-Dawley rats of 3.85 and 7.70 g of destoned Arbequina table olives/kg. Plasma samples were analyzed using a fully validated method consisting of liquid extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Noncompartmental PK analysis of hydroxytyrosol demonstrated linear PK between doses of 2.95 and 5.85 mg hydroxytyrosol/kg. Half-life was approximately 2.5 h, while mean residence time was around 4 h. Clearance occurred by conversion to two sulfate and two glucuronide conjugates. The area under the plasma concentration-time curve (AUC) ratios of metabolites versus parent hydroxytyrosol was approximately 7-9-fold for the sulfate and below 0.25 for the glucuronide, indicating sulfation as the predominant metabolic pathway. Despite extensive metabolism, hydroxytyrosol remained in plasma for up to 8 h with AUCs of 4293 and 8919 min·nmol/L for the doses of 3.85 and 7.70 g/kg, respectively. Therefore, table olives provide a more sustained plasma profile than other foods containing hydroxytyrosol, which may enhance its health-protecting activities.

Accumulation of cadmium (Cd) ions in soil is an increasingly acute ecological problem in agriculture production. Selenium nanoparticles (SeNPs) can mediate Cd tolerance in plants; however, the underlying mechanisms remain unclear. Herein, we show that the foliar application of SeNPs improved the adaptive capacity of tomato plants to decrease Cd-induced damage. SeNPs induced more Cd in roots but not in shoots despite greater accumulation of selenium and sulfur in both tissues and high selenate influx. Additionally, SeNPs significantly increased thiol compounds, including glutathione, cysteine, and phytochelatins, contributing to enhanced Cd detoxification. Importantly, SeNPs induced the expression of sulfate transporters 1:3 , S-adenosylmethionine 1 and polyamine transporter 3 . Then, experiments with mutants of these genes showed that SeNP-reduced Cd stress largely relies on the levels and shoot-to-root transport of selenium/sulfur and polyamines. These findings highlight the potential of SeNPs to improve crop production and phytoremediation in heavy metal-contaminated soils.

Microbially induced corrosion (MIC) on concrete represents a serious issue impairing the lifespan of coastal/marine infrastructure. However, currently developed concrete corrosion protection strategies have limitations in wide applications. Here, a biomineralization method was proposed to form a biomineralized film on concrete surfaces for corrosion inhibition. Laboratory seawater corrosion experiments were conducted under different conditions [e.g., chemical corrosion (CC), MIC, and biomineralization for corrosion inhibition]. A combination of chemical and mechanical property measurements of concrete (e.g., sulfate concentrations, permeability, mass, and strength) and a genotypic-based investigation of formed concrete biofilms was conducted to evaluate the effectiveness of the biomineralization approach on corrosion inhibition. The results show that MIC resulted in much higher corrosion rates than CC. However, the biomineralization treatment effectively inhibited corrosion because the biomineralized film decreased the total and relative abundance of sulfate-reducing bacteria (SRB) and acted as a protective layer to control the diffusion of sulfate and isolate the concrete from the corrosive SRB communities, which helps extend the lifespan of concrete structures. Moreover, this technique had no negative impact on the native marine microbial communities. Our study contributes to the potential application of biomineralization for corrosion inhibition to achieve long-term sustainability for major marine concrete structures.

The mechanism of sulfate formation during winter haze events in North China remains largely elusive. In this study, the multiple sulfur isotopic composition of sulfate in different grain-size aerosol fractions collected seasonally from sampling sites in rural, suburban, urban, industrial, and coastal areas of North China are used to constrain the mechanism of SO 2 oxidation at different levels of air pollution. The Δ 33 S values of sulfate in aerosols show an obvious seasonal variation, except for those samples collected in the rural area. The positive Δ 33 S signatures (0‰ < Δ 33 S < 0.439‰) observed on clean days are mainly influenced by tropospheric SO 2 oxidation and stratospheric SO 2 photolysis. The negative Δ 33 S signatures (-0.236‰ < Δ 33 S < ∼0‰) observed during winter haze events (PM 2.5 > 200 μg/m 3 ) are mainly attributed to SO 2 oxidation by H 2 O 2 and transition metal ion catalysis (TMI) in the troposphere. These results reveal that both the H 2 O 2 and TMI pathways play critical roles in sulfate formation during haze events in North China. Additionally, these new data provide evidence that the tropospheric oxidation of SO 2 can produce significant negative Δ 33 S values in sulfate aerosols.

Amphiphiles are among the most extensively studied building blocks that self-assemble into cell-like compartments. Most literature suggested that the building blocks/amphiphiles of early Earth (fatty acid-based membrane) were much simpler than today's phospholipids. To establish the bridge between the prebiotic fatty acid era and the modern phospholipid era, the investigation and characterization of alternate building blocks that form protocellular membranes are necessary. Herein, we report the potential prebiotic synthesis of alkyl phosphate, alkyl carboxylate, and alkyl sulfate amphiphiles (anionic) using dry-down reactions and demonstrate a more general role of cationic amino acid-based amphiphiles to recruit the anionic amphiphiles via ion-pair, hydrogen bonding, and hydrophobic interactions. The formation and self-assembly of the catanionic (mixed) amphiphilic system to vesicular morphology were characterized by turbidimetric, dynamic light scattering, transmission electron microscopy, fluorescence lifetime imaging microscopy, and glucose encapsulation experiments. Further experiments suggest that the phosphate-based vesicles were more stable than the alkyl sulfate and alkyl carboxylate-based systems. Moreover, the alkyl phosphate system can form vesicles at prebiotically relevant acidic pH (5.0), while alkyl carboxylate mainly forms cluster-type aggregates. An extended supramolecular polymer-type network formation via H-bonding and ion-pair interactions might order the membrane interface and stabilize the phosphate-based vesicles. The results suggest that phosphate-based amphiphiles might be a superior successor to fatty acids as early compartment building blocks. The work highlights the importance of previously unexplored building blocks that participate in protocellular membrane formation to encapsulate important precursors required for the functions of early life.

The production of fossil fuels, including oil, gas, and coal, retains a dominant share in US energy production and serves as a major anthropogenic source of methane, a greenhouse gas with a high warming potential. In addition to directly emitting methane into the air, fossil fuel production can release methane into groundwater, and that methane may eventually reach the atmosphere. In this study, we collected 311 water samples from an unconventional oil and gas (UOG) production region in Pennsylvania and an oil and gas (O&G) and coal production region across Ohio and West Virginia. Methane concentration was negatively correlated to distance to the nearest O&G well in the second region, but such a correlation was shown to be driven by topography as a confounding variable. Furthermore, sulfate concentration was negatively correlated with methane concentration and with distance to coal mining in the second region, and these correlations were robust even when considering topography. We hypothesized that coal mining enriched sulfate in groundwater, which in turn inhibited methanogenesis and enhanced microbial methane oxidation. Thus, this study highlights the complex interplay of multiple factors in shaping groundwater methane concentrations, including biogeochemical conversion, topography, and conventional fossil extraction.

Per- and polyfluoroalkyl substances (PFAS) are widely used anthropogenic chemicals. Because of the strength of the carbon-fluorine bond, PFAS are not destroyed in typical water treatment processes. Sulfate (SO 4 •- ) and hydroxyl ( • OH) radicals can oxidize some PFAS, but the behavior of per- and polyfluoroalkyl ether acids (PFEAs) in processes involving SO 4 •- and • OH is poorly understood. In this study, we determined second-order rate constants ( k ) describing the oxidation of 18 PFAS, including 15 novel PFEAs, by SO 4 •- and • OH. Among the studied PFAS, 6:2 fluorotelomer sulfonate reacted most readily with • OH [ k •OH = (1.1-1.2) × 10 7 M -1 s -1 ], while polyfluoroalkyl ether acids containing an -O-CFH- moiety reacted more slowly [ k •OH = (0.5-1.0) × 10 6 M -1 s -1 ]. In the presence of SO 4 •- , polyfluoroalkyl ether acids with an -O-CFH- moiety reacted more rapidly [ k SO4 •- = (0.89-4.6) × 10 6 M -1 s -1 ] than perfluoroalkyl ether carboxylic acids (PFECAs) and a chloro-perfluoro-polyether carboxylic acid (ClPFPECA) [ k SO4 •- = (0.85-9.5) × 10 4 M -1 s -1 ]. For homologous series of perfluoroalkyl carboxylic acids, linear and branched monoether PFECAs, and multiether PFECAs, PFAS chain length had little impact on second-order rate constants. SO 4 •- reacted with the carboxylic acid headgroup of perfluoroalkyl carboxylic acids and PFECAs. In contrast, for polyfluoroalkyl ether carboxylic and sulfonic acids with an -O-CFH- moiety, the site of SO 4 •- attack was the -O-CFH- moiety. Perfluoroalkyl ether sulfonic acids were not oxidized by SO 4 •- and • OH under the conditions evaluated in this study.

Indophenol sulfate (IS) and methylmalonic acid (MMA) are biomarkers of chronic kidney disease (CKD) and diabetes polyneuropathy (DPN), respectively. Portable and accurate monitoring of IS and MMA is very important to ensuring human health. The dense convolutional network (DenseNet) with image recognition has great potential in fluorescence sensing, but developing a platform with high precision and portability to diagnose the disease still faces huge challenges. Herein, we developed a high-sensitivity platform with a fluorescence material, a smartphone, and the DenseNet to monitor IS and MMA. A red-emitting Eu@PFC-13 ( 1 ) is prepared, and 1 shows high selectivity and low detection limits (DLs) to detect IS and MMA. The sensing mechanism of 1 toward IS and MMA is investigated by experiments and theoretical calculation. For detecting IS and MMA in serum and urine, 1 is fabricated into an Eu@PFC-13/AG ( 2 ) film with DLs of 1.4 and 1.6 μM, respectively. In addition, a portable smartphone platform is designed to monitor IS and MMA with high precision. Moreover, the DenseNet is constructed by Python, which can output the concentration of analytes by identifying fluorescence images and judge whether any is in a dangerous range. This work not only proposes a novel method that integrates a fluorescence material, a smartphone, and deep learning to detect analytes but also opens a new way for the diagnosis of CKD and DPN.

Anions accompanying inorganic fertilizers, such as chloride and sulfate ions, potentially affect the solubility, uptake, and transport of Cd to rice grains. However, the role of anions in controlling Cd transport in the soil-soil solution-Fe plaque-rice plant continuum remains poorly understood. Cd isotope ratios were applied to Cd-contaminated soil pots, hydroponic rice, and adsorption experiments with or without KCl and K 2 SO 4 treatments to decipher transport processes in the complex soil-rice system. The chloride and sulfate ions increased the Cd concentrations in the soil solution, Fe plaque, and rice plants. Accordingly, the magnitude of positive fractionation from soil to the soil solution was less pronounced, but that between soil and Fe plaque or rice plant is barely varied. The similar isotope composition of Fe plaque and soil, and the similar fractionation magnitude between Fe plaque and the solution and between goethite and the solution, suggested that desorption-sorption between iron oxides and the solution could be important at the soil-soil solution-Fe plaque continuum. This study reveals the roles of chloride and sulfate ions: (i) induce the mobility of light Cd isotopes from soil to the soil solution, (ii) chloro-Cd and sulfato-Cd complexes contribute to Cd immobilization in the Fe plaque and uptake into roots, and (iii) facilitate second leaves/node II-to-grain Cd transport within shoots. These results provide insights into the anion-induced Cd isotope effect in the soil-rice system and the roles of anions in facilitating Cd migration and transformation.

The heterogeneous oxidation of SO 2 by NO 2 has been extensively proposed as an important pathway of sulfate production during haze events in China. However, the kinetics and mechanism of oxidation of SO 2 by NO 2 on the surface of complex particles remain poorly understood. Here, we systematically explore the mechanism and kinetics of the reaction between SO 2 and NO 2 on diesel black carbon (DBC) under light irradiation. The experimental results prove that DBC photochemistry can not only significantly promote the heterogeneous reduction of NO 2 to produce HONO via transferring photoinduced electrons but also indirectly promote OH radical formation. These reduction products of NO 2 as well as NO 2 itself greatly promote the heterogeneous oxidation of SO 2 on DBC. NO 2 oxidation, HONO oxidation, and the surface photo-oxidation process are proven to be three major surface oxidation pathways of SO 2 . The kinetics results indicate that the surface photooxidation pathway accounts for the majority of the total SO 2 uptake (∼63%), followed by the HONO oxidation pathway (∼27%) and direct oxidation by NO 2 (∼10%). This work highlights the significant synergistic roles of DBC, NO 2 , and light irradiation in enhancing the atmospheric oxidation capacity and promoting the heterogeneous formation of sulfate.

The mechanism of drug-induced skin rash is not well understood. Circumstantial evidence suggests that the covalent binding of a reactive metabolite is involved in the mechanism of most idiosyncratic drug reactions. However, there is a limited quantity of drug metabolizing enzymes in the skin, except for sulfotransferases. It is possible that some drugs are metabolized to reactive sulfate metabolites that are responsible for skin rashes. For example, nevirapine-induced skin rash involves metabolism of nevirapine to 12-hydroxy-nevirapine, which is further metabolized by sulfotransferase in the skin to a reactive benzylic sulfate that covalently binds to proteins. The working hypothesis is that lamotrigine, valdecoxib, and sertraline skin rashes involve the formation of reactive sulfate in the skin. Lamotrigine- N -oxide, hydroxy-valdecoxib, and hydroxy-sertraline were tested as substrates with known human sulfotransferases. Hydroxy-valdecoxib and the benzylic alcohol metabolite of sertraline were not substrates for human sulfotransferases. Therefore, this pathway is presumably not involved in the mechanism by which they cause skin rashes. In contrast, lamotrigine- N -oxide is a substrate for several human sulfotransferases and the sulfate is chemically reactive. Furthermore, lamotrigine- N -sulfate not only alkylates proteins as we described previously but also forms the sulfate of tyrosine, suggesting another possible mechanism for protein modification. This study has further added to the understanding of the potential of the sulfotransferase pathways and protein sulfation to play a role in drug-induced skin rash.

It is known that the presence of sulfate decreases the methane yield in the anaerobic digestion systems. Sulfate-reducing bacteria can convert sulfate to hydrogen sulfide competing with methanogens for substrates such as H 2 and acetate. The present work aims to elucidate the microbial interactions in biogas production and assess the effectiveness of electron-conductive materials in restoring methane production after exposure to high sulfate concentrations. The addition of magnetite led to a higher methane content in the biogas and a sharp decrease in the level of hydrogen sulfide, indicating its beneficial effects. Furthermore, the rate of volatile fatty acid consumption increased, especially for butyrate, propionate, and acetate. Genome-centric metagenomics was performed to explore the main microbial interactions. The interaction between methanogens and sulfate-reducing bacteria was found to be both competitive and cooperative, depending on the methanogenic class. Microbial species assigned to the Methanosarcina genus increased in relative abundance after magnetite addition together with the butyrate oxidizing syntrophic partners, in particular belonging to the Syntrophomonas genus. Additionally, Ruminococcus sp. DTU98 and other species assigned to the Chloroflexi phylum were positively correlated to the presence of sulfate-reducing bacteria, suggesting DIET-based interactions. In conclusion, this study provides new insights into the application of magnetite to enhance the anaerobic digestion performance by removing hydrogen sulfide, fostering DIET-based syntrophic microbial interactions, and unraveling the intricate interplay of competitive and cooperative interactions between methanogens and sulfate-reducing bacteria, influenced by the specific methanogenic group.

Amyloid β-protein (Aβ42) aggregates have been demonstrated to induce cognitive decline and neurodegeneration in Alzheimer's disease (AD). Thus, functional food ingredients that inhibit Aβ42 aggregation are valuable for AD prevention. Although several food ingredients have been studied for their anti-aggregation activity, information on their bioavailability in the brain, incorporated forms, and relevance to AD etiology is limited. Here, we first detected the sulfate- and glucuronic-acid-conjugated forms of green perilla-derived chalcone ( 1 ) and taxifolin ( 2 ), which inhibit Aβ42 aggregation, in the brain, small intestine, and plasma of mice ( 1 and 2 were administered orally) using ultra-performance liquid chromatography-tandem mass spectrometry. We observed that the conjugated metabolites (sulfate ( 4 ) and glucuronide ( 5 )) of 1 prevented the fibrillization and oligomerization of Aβ42. These findings imply that the conjugated metabolites of 1 can prove beneficial for AD treatment.

Our previous study found that fucogalactan sulfate (FS) from Laminaria japonica exhibited significant hypolipidemic effects. To further elucidate the mechanism, we first constructed a dyslipidemia mouse model with humanized gut microbiota and proved the main differential metabolic pathway involved bile acid metabolism. Then, we evaluated the beneficial effects of FS on dyslipidemia in this model mice, which revealed that oral FS administration reduced serum cholesterol levels and mitigated liver fat accumulation. Gut microbiota and microbiome analysis showed FS increased the abundance of Ruminococcaceae&#95;NK4A214&#95;group , GCA-900066755 , and Eubacterium , which were positively associated with the fecal DCA, β-MCA, and HDCA. Further investigation demonstrated that FS inhibited the hepatic farnesoid X receptor (FXR), while activating the intestinal FXR-FGF19 pathway, leading to suppression of CYP7A1 and CYP8B1, as well as potentially reduced bile acid synthesis and lipid absorption. Overall, FS regulated lipid metabolism in diet-induced humanized dyslipidemia mice via the bile acid-mediated intestinal FXR-FGF19-CYP7A1/CYP8B1 pathway.

Sulfation widely exists in the eukaryotic proteome. However, understanding the biological functions of sulfation in peptides and proteins has been hampered by the lack of methods to control its spatial or temporal distribution in the proteome. Herein, we report that fluorosulfate can serve as a latent precursor of sulfate in peptides and proteins, which can be efficiently converted to sulfate by hydroxamic acid reagents under physiologically relevant conditions. Photocaging the hydroxamic acid reagents further allowed for the light-controlled activation of functional sulfopeptides. This work provides a valuable tool for probing the functional roles of sulfation in peptides and proteins.

Mineral dust serves as a significant source of sulfate aerosols by mediating heterogeneous sulfur dioxide (SO 2 ) oxidation in the atmosphere. Given that a considerable proportion of small organic acids are deposited onto mineral dust via long-range transportation, understanding their impact on atmospheric SO 2 transformation and sulfate formation is of great importance. This study investigates the effect of oxalate on heterogeneous SO 2 uptake and oxidation phenomenon by in situ FTIR, theoretical calculation, and continuous stream experiments, exploiting hematite (Fe 2 O 3 ) as an environmental indicator. The results highlight the critical role of naturally deposited oxalate in mononuclear monodentate coordinating surface Fe atoms of Fe 2 O 3 that enhances the activation of O 2 for oxidizing SO 2 into sulfate. Meanwhile, oxalate increases the hygroscopicity of Fe 2 O 3 , facilitating H 2 O dissociation into reactive hydroxyl groups and further augmenting the SO 2 uptake capacity of Fe 2 O 3 . More importantly, other conventional iron minerals, such as goethite and magnetite, as well as authentic iron-containing mineral dust, exhibit similar oxalate-promoted sulfate accumulation behaviors. Our findings suggest that oxalate-assisted SO 2 oxidation on iron minerals is one of the important contributors to secondary sulfate aerosols, especially during the nighttime with high relative humidity.

Anaerobic and aerobic granular sludge processes are widely applied in wastewater treatment. In these systems, microorganisms grow in dense aggregates due to the production of extracellular polymeric substances (EPS). This study investigates the sialylation and sulfation of anionic glyconconjugates in anaerobic and aerobic granular sludges collected from full-scale wastewater treatment processes. Size exclusion chromatography revealed a wide molecular weight distribution (3.5 to >5500 kDa) of the alkaline-extracted EPS. The high-molecular weight fraction (>5500 kDa), comprising 16.9-27.4% of EPS, was dominant with glycoconjugates. Mass spectrometry analysis and quantification assays identified nonulosonic acids (NulOs, e.g., bacterial sialic acids) and sulfated groups contributing to the negative charge in all EPS fractions. NulOs were predominantly present in the high-molecular weight fraction (47.2-84.3% of all detected NulOs), while sulfated glycoconjugates were distributed across the molecular weight fractions. Microorganisms, closely related to genera found in the granular sludge communities, contained genes responsible for NulO and sulfate group synthesis or transfer. The similar distribution patterns of sialylation and sulfation of the anionic glycoconjugates in the EPS samples indicate that these two glycoconjugate modifications commonly occur in the EPS of aerobic and anaerobic granular sludges.

Electrochemically mediated Fe(II)/Fe(III) redox-coupled uranium extraction can efficiently reduce the cell voltage of electrochemical uranium extraction (EUE). How to regulate the surface structure to enhance the uranium acyl ion adsorption capacity and strengthen the Fe(II)/Fe(III) redox cycle process is crucial for EUE. In this work, we developed surface sulfated nanoreduced iron (S-NRI) for EUE and exhibited improved properties for EUE at an ultralow cell voltage (-0.1 V). Compared with a nanoreduced iron (NRI) adsorbent, S-NRI displayed faster electrochemical extraction kinetics properties and higher extraction efficiency and capacity for uranium. In a more complex seawater electrolyte containing uranyl ion concentration ranging from 1 to 20 ppm, the removal efficiency could reach almost ∼100% after EUE for 24 h. At a higher 50 ppm uranium acyl ion concentration in a seawater electrolyte, S-NRI exhibited higher extraction capacity (755.03 mg/g), which is better than 528.53 mg/g of NRI at a cell voltage of -0.1 V. Outstanding EUE property could be attributed to the fact that sulfate species (M-SO 4 2- ) on the S-NRI surface not only enhanced selective adsorption of uranyl ions but also strengthened the Fe(II)/Fe(III) redox cycle, which accelerated electron transfer between Fe(II) and U(VI), promoted the regeneration of Fe(II) active sites, and finally enhanced the EUE property.

Adenylylsulfate reductase (Apr) is a flavoprotein with a dissimilatory sulfate reductase function. Its ability to catalyze the reverse reaction in sulfur oxidizers has propelled a complex phylogenetic history of transfers with sulfate reducers and made this enzyme an important protein in ocean sulfur cycling. As part of a graduate course, we analyzed metaproteomic data from the Ocean Protein Portal and observed evidence of Apr alpha (AprA) and beta (AprB) subunits in the Central Pacific Ocean. The protein was originally taxonomically attributed to Chlorobium tepidum TLS , a green sulfur bacterium. However, our phylogenomic and oceanographic contextual analysis contradicted this label, instead showing that this protein is consistent with the genomic material from the newly discovered Candidatus Lambdaproteobacteria class, implying that the ecological role of this lineage in oxygen minimum twilight zones is underappreciated. This study illustrates how metaproteogenomic analysis can contribute to more accurate metagenomic/proteomic annotations and comprehensive ocean biogeochemical processes conducive to course-based research experiences.

Barite (BaSO 4 ) precipitation is one of the most ubiquitous examples of secondary sulfate mineral scaling in shale oil and gas reservoirs. Often, a suite of chemical additives is used during fracturing operations to inhibit the accumulation of mineral scales, though their efficacy is widely varied and poorly understood. This study combines experimental data and multi-component numerical reactive transport modeling to offer a more comprehensive understanding of the geochemical behavior of barite accumulation in shale matrices under conditions typical of fracturing operations. A variety of additives and conditions are individually tested in batch reactor experiments to identify the factors controlling barite precipitation. Our experimental results demonstrate a pH dependence in the rate of barite precipitation, which we use to develop a predictive model including a pH-dependent term that satisfactorily reproduces our observations. This model is then extended to consider the behavior of three major shale samples of highly variable mineralogy (Eagle Ford, Marcellus, and Barnett). This data-validated model offers a reliable tool to predict and ultimately mitigate against secondary mineral accumulation in unconventional shale reservoirs.

Methane is a powerful greenhouse gas that is produced in large quantities in marine sediments. Microbially mediated oxidation of methane in sediments, when in balance with methane production, prevents the release of methane to the overlying water. Here, we present a gene-based reactive transport model that includes both microbial and geochemical dynamics and use it to investigate whether the rate of growth of methane oxidizers in sediments impacts the efficiency of the microbial methane filter. We focus on iron- and methane-rich coastal sediments and, with the model, show that at our site, up to 10% of all methane removed is oxidized by iron and manganese oxides, with the remainder accounted for by oxygen and sulfate. We demonstrate that the slow growth rate of anaerobic methane-oxidizing microbes limits their ability to respond to transient perturbations, resulting in periodic benthic release of methane. Eutrophication and deoxygenation decrease the efficiency of the microbial methane filter further, thereby enhancing the role of coastal environments as a source of methane to the atmosphere.

Highly efficient sulfate reduction coupled to autotrophic denitrification plus nitrification is demonstrated by integrating an anaerobic membrane bioreactor (AnMBR) with a membrane aerated biofilm reactor (MABR). Concurrent chemical oxygen demand (COD) removal and sulfate reduction were accomplished in the AnMBR, while simultaneous nitrification and autotrophic denitrification were carried out in the MABR. Separate operation of the MABR achieved >90% total nitrogen (TN) removal when the N/S ratio was controlled at 0.4 gN/gS. The integrated AnMBR-MABR system efficiently resisted influent variability, realizing >95% COD removal in the AnMBR and >75% TN removal in the MABR when the influent COD/N ratio was above 4 gCOD/gN. Membrane fouling did not happen during ∼170 days of operation. Due to sulfide oxidation, a large amount of elemental sulfur (S 0 ) accumulated in the MABR biofilm, where it served as an electron donor for denitrification. Microbial community analysis indicated that Nitrospira and Thiobacillus played key roles in nitrification and sulfide-driven denitrification, respectively, and that they occurred in different layers of the biofilm. This novel process offers advantages of a small land-area footprint, modular operation, and high efficiency electron-donor and oxygen utilizations, particularly for wastewater with a low COD/N ratio.

Elevated particulate sulfate concentrations have been frequently observed in coastal areas when air masses are influenced by continental emissions, especially combustion sources like biomass burning. We studied the SO 2 uptake by laboratory-generated droplets containing incense smoke extracts and sodium chloride (IS-NaCl) under irradiation and found enhanced sulfate production over pure NaCl droplets, attributable to photosensitization induced by constituents in IS. Low relative humidity and high light intensity facilitated sulfate formation and increased the SO 2 uptake coefficient by IS-NaCl particles. Aging of the IS particles further enhanced sulfate production, attributable to the enhanced secondary oxidant production promoted by increased proportions of nitrogen-containing CHN and oxygen- and nitrogen-containing CHON species under light and air. Experiments using model compounds of syringaldehyde, pyrazine, and 4-nitroguaiacol verified the enhancements of CHN and CHON species in sulfate formation. This work provides experimental evidence of enhanced sulfate production in laboratory-generated IS-NaCl droplets via enhanced secondary oxidant production triggered by photosensitization in multiphase oxidation processes under light and air. Our results can shed light on the possible interactions between sea salt and biomass burning aerosols in enhancing sulfate production.

A cost-effective and environmentally friendly approach is proposed for producing N- and S-codoped multicolor-emission carbon dots (N- and S-codoped MCDs) at a mild reaction temperature (150 °C) and relatively short time (3 h). In this process, adenine sulfate acts as a novel precursor and doping agent, effectively reacting with other reagents such as citric acid, para -aminosalicylic acid, and ortho -phenylenediamine, even during solvent-free pyrolysis. The distinctive structures of reagents lead to the increased amount of graphitic nitrogen and sulfur doping in the N- and S-codoped MCDs. Notably, the obtained N- and S-codoped MCDs exhibit considerable fluorescence intensities, and their emission color can be adjusted from blue to yellow. The observed tunable photoluminescence can be attributed to variations in the surface state and the amount of N and S contents. Furthermore, due to the favorable optical properties, good water solubility and biocompatibility, and low cytotoxicity, these N- and S-codoped MCDs, especially green carbon dots, are successfully applied as fluorescent probes for bioimaging. The affordable and environmentally friendly synthesis method employed to create N- and S-codoped MCDs, combined with their remarkable optical properties, offers a promising avenue for their use in various fields, particularly in biomedical applications.

Current techniques for identifying and quantifying sulfate radicals (SO 4 · - ) in SO 4 · - -based advanced oxidation processes (SR-AOPs) are unsatisfactory due to their low selectivity, poor reliability, and limited feasibility for real-time quantification. In this study, naproxen (NAP) was employed as a turn-on luminescent probe for real-time quantification of SO 4 · - in SR-AOPs. The chemiluminescence(CL) yield (Φ CL ) of the reaction of NAP with SO 4 · - was first determined to be 1.49 × 10 -5 E mol -1 with the bisulfite activation by cerium(IV) [Ce(IV)/BS] process. Then, the maximum peak concentrations of SO 4 · - in the Ce(IV)/BS-NAP process was quantified to be ∼10 -11 M based on the derived equation. Since Φ CL of the reaction of NAP with SO 4 · - was much greater than that with other reactive oxidizing species (ROS), the developed CL method worked well in selective quantification of SO 4 · - in various SR-AOPs (e.g., the activation of peroxymonosulfate and persulfate by iron processes). Finally, the electron transfer from NAP to SO 4 · - was proposed to be the critical step for CL production. This work provides a novel CL method for real-time quantification of SO 4 · - , which facilitates the development of SR-AOPs and their application in water and wastewater treatment.

Batch kinetic experiments are combined with X-ray absorption spectroscopy (XAS) to compare the sorption of Mn(II), Co(II), Ni(II), Zn(II), and Cd(II) with sulfated green rust (GR) in anoxic pre-equilibrated suspensions at pH 8 over a timespan of 1 h to 1 week. The XAS data suggest that all five divalent metals coordinate at Fe(II) sites of the GR sorbent, whereas the batch results show that GR exhibits bimodal sorption behavior, with fast but limited uptake of Mn(II) and Cd(II) and much more extensive sorption of Co(II), Ni(II), and Zn(II) that continues throughout the entire experimental timeframe. We attribute these observations to differences in the affinity and extent of divalent metal substitution in Fe(II) sites of the GR lattice as controlled by ionic size. Divalent metals smaller than Fe(II) [ i.e. , Co(II), Ni(II), and Zn(II)] are readily accommodated and undergo coprecipitation during GR dissolution-reprecipitation. In contrast, divalent metals larger than Fe(II) [ i.e. , Mn(II) and Cd(II)] have a low affinity for substitution and remain coordinated at the surface following limited exchange with Fe(II) (s) at GR particle edges. These results imply that GR may strongly affect the solubility of Co(II), Ni(II), and Zn(II) in reducing geochemical systems but will have little impact on the retention of Cd(II) and Mn(II).

Drug interactions involving the inhibition of hepatic organic anion transporting polypeptides (OATPs) 1B1 and OATP1B3 are considered important. Therefore, we sought to study various sulfated bile acids (BA-S) as potential clinical OATP1B1/3 biomarkers. It was determined that BA-S [e.g., glycochenodeoxycholic acid 3-O-sulfate (GCDCA-S) and glycodeoxycholic acid 3-O-sulfate (GDCA-S)] are substrates of OATP1B1, OATP1B3, and sodium-dependent taurocholic acid cotransporting polypeptide (NTCP) transfected into human embryonic kidney 293 cells, with minimal uptake evident for other solute carriers (SLCs) like OATP2B1, organic anion transporter 2, and organic cation transporter 1. It was also shown that BA-S uptake by plated human hepatocytes (PHH) was inhibited (≥96%) by a pan-SLC inhibitor (rifamycin SV), and there was greater inhibition (≥77% versus ≤12%) with rifampicin (OATP1B1/3-selective inhibitor) than a hepatitis B virus myristoylated-preS1 peptide (NTCP-selective inhibitor). Estrone 3-sulfate was also used as an OATP1B1-selective inhibitor. In this instance, greater inhibition was observed with GDCA-S (76%) than GCDCA-S (52%). The study was expanded to encompass the measurement of GCDCA-S and GDCA-S in plasma of SLCO1B1 genotyped subjects. The geometric mean GDCA-S concentration was 2.6-fold (90% confidence interval 1.6, 4.3; P = 2.1 × 10 -4 ) and 1.3-fold (1.1, 1.7; P = 0.001) higher in individuals homozygous and heterozygous for the SLCO1B1 c.521T > C loss-of-function allele, respectively. For GCDCA-S, no significant difference was noted [1.2-fold (0.8, 1.7; P = 0.384) and 0.9-fold (0.8, 1.1; P = 0.190), respectively]. This supported the in vitro data indicating that GDCA-S is a more OATP1B1-selective substrate (versus GCDCA-S). It is concluded that GCDCA-S and GDCA-S are viable plasma-based OATP1B1/3 biomarkers, but they are both less OATP1B1-selective when compared to their corresponding 3-O-glucuronides (GCDCA-3G and GDCA-3G). Additional studies are needed to determine their utility versus more established biomarkers, such as coproporphyrin I, for assessing inhibitors with different OATP1B1 (versus OATP1B3) inhibition signatures.

The nucleophilicities of the oxidants hydroperoxide, hypochlorite, hypobromite, bromite, and peroxymonosulfate were determined by following the kinetics of their reactions with a series of benzhydrylium ions of known electrophilicity (E) in alkaline, aqueous solutions at 20 °C. The reactivities of the oxidants correlate only weakly with their basicities. Analyzing the rate constants by using the relationship log k2 = sN(N + E) gave the parameters N (and sN), which were applied to predict the rates of Weitz-Scheffer epoxidations. [ABSTRACT FROM AUTHOR]

Micellisation of two binary mixtures, sodium decyl sulfate (NaDS)-sodium deoxycholate (NaDC) and sodium decyl sulfate (NaDS)-sodium hyodeoxychlolate (NaHDC), is examined, in consideration with the different molar fractions of the monomers (x = 0.1-0.9). In bile acids, the OH groups attached to steroid skeletons are spatially ecraned, while the sulfate group of NaDS is not ecraned. Thus, NaDC and NaHDC in relation to NaDS have different coordination numbers in the micelle pseudophase. On the basis of stereochemical analysis, rational design shows that the excess Gibbs energy (GE) of formation of the binary mixed micelle throughout the whole composition range can be described with a two-parameter Margules function, while the GE function from the regular solution theories is applicable only in the narrow interval of the bile salts molar fractions (x = 0.5-0.8). Coefficient of activity (hypothetical) of the infinitely diluted mixed micelle of NaDS in the presence of NaDC shows significant thermodynamic stabilization of decyl sulfate ions in comparison with the infinitely diluted hypothetical mixed micelle with NaHDC. This stabilization of decyl sulfate ions is probably due to the cooperative binding of NaDS by parallel OH groups of NaDC. [ABSTRACT FROM AUTHOR]

High-throughput screening (HTS) methods have become decisive for the discovery and development of new biocatalysts and their application in numerous fields. Sulfatases, a broad class of biocatalysts that hydrolyze sulfate esters, are involved in diverse relevant cellular functions (e.g., signaling and hormonal regulation) and are therefore gaining importance, particularly in the medical field. Additionally, various technical applications have been recently devised. One of the major challenges in the field of enzyme development is the sensitive and high-throughput detection of the actual product of the biocatalyst of interest without the need for chromophore analogues. Addressing this issue, a colorimetric assay for sulfatases was developed and validated for detecting sulfate through a two-step enzymatic cascade, with a linear detection range of 3.3 (limit of detection) up to 250 μM. The procedure is compatible with relevant compounds employed in sulfatase reactions, including cosolvents, cations, and buffers. The assay was optimized and performed as part of a 96-well screening workflow that included bacterial growth, heterologous sulfatase expression, cell lysis, sulfate ester hydrolysis, inactivation of cell lysate, and colorimetric sulfate determination. With this procedure, the activity of an aryl and an alkyl sulfatase could be confirmed and validated. Overall, this assay provides a simple and fast alternative for screening and engineering sulfatases from DNA libraries (e.g., using metagenomics) with medical or synthetic relevance. [ABSTRACT FROM AUTHOR]

A unique asymmetric total synthesis of the unnatural enantiomer of pregnanolone, as well as a study of its biological activity at the NMDA receptor, is reported. The asymmetry is introduced by a highly atom-economic organocatalytic Robinson annulation. A new method for the construction of the cyclopentane D-ring consisting of CuI-catalyzed conjugate addition and oxygenation followed by thermal cyclization employing the persistent radical effect was developed. ent-Pregnanolone sulfate is surprisingly only 2.6-fold less active than the natural neurosteroid. [ABSTRACT FROM AUTHOR]

Tubelike Co3O4 was successfully prepared by a facile electrospinning route combined with a subsequent calcining treatment. The as-prepared tubelike Co3O4 was exploited as peroxidase mimics and to activate peroxymonosulfate (PMS) to produce sulfate radicals. The tubelike Co3O4 exhibited intrinsic peroxidase-like activity and high ability of activating PMS to degrade 2,4-dichlorophenol compared with the powders for the high specific surface area and surface Co2+ and adsorbed oxygen contents. Furthermore, the electronic properties of Co3O4 and the catalytic mechanism on H2O2 and PMS were investigated by electron spin resonance test and density functional theory calculation. This study details the insights into Co3O4 nanomaterials for activation of peroxides and application in sustainable remediation. [ABSTRACT FROM AUTHOR]

In this work, a facile synthesis of ceria and sulfated zirconia (SZ) incorporated SBA-15 catalyst was conducted. The supported SZ reveals promising Brønsted/Lewis acid and relatively low base strength, and the base strength of the catalyst is significantly enhanced by introducing highly dispersed ceria into the network of SZ incorporated SBA-15. Systematic study of catalyst activities were carried out in iPrOH/DMSO solvent conversion of glucose to 5-hydroxymethylfurfural (HMF). It is found that the isomerization process of glucose to fructose was promoted by coexisting base and Lewis acid sites, and the dehydration reaction of reactively formed fructose to HMF was directed by Brønsted acid sites. Up to 66.5% HMF yield and 70.8% selectivity can be obtained in a 90 vol % iPrOH-mediated DMSO solvent. Through the reaction system developed in this paper, use of a large amount of environmentally hazardous solvent can be avoided, and a new method of large-scale economically viable processes for biomass conservation is provided. [ABSTRACT FROM AUTHOR]

(-)-6'-β-Fluoro-aristeromycin (2), a potent inhibitor of S-adenosylhomocysteine (AdoHcy) hydrolase, has been synthesized via stereoselective electrophilic fluorination followed by a purine base build-up approach. Interestingly, purine base condensation using a cyclic sulfate resulted in a synthesis of (+)-5'-β-fluoro-isoaristeromycin (2a). Computational analysis indicates that the fluorine atom controlled the regioselectivity of the purine base substitution. [ABSTRACT FROM AUTHOR]

The presence of impurities in solution during crystallization can influence the crystallization kinetics of the desired product. Consequently, this affects the product quality parameters such as the crystal size distribution (CSD), purity, and morphology. This paper focuses on the application of eutectic freeze crystallization (EFC) to the purification of petrochemical brine rich in sulfate salts. The effect of phenol on the CSD, nucleation and growth rates, purity, and morphology of ice and sodium sulfate decahydrate crystals was evaluated using a batch EFC setup. Nucleation and growth rates were obtained from in situ image acquisition and analyses. In the presence of 0.2 wt % phenol, larger crystals were obtained for both ice and sodium sulfate decahydrate due to increased growth rates and reduced nucleation rates. The crystal habit of both ice and salt was not modified by the phenol impurity. Ice crystals presented elongated disk shapes and dendritic habit, and crystal sizes up to 1000 μm were obtained. Salt particles exhibited prismatic shape and monoclinic class as expected for Na2SO4·10H2O. Ice purity of about 97% was obtained before washing in the presence of phenol. Three washing cycles increased the ice purity to 100% implying that impurities were physically adhered on the ice surfaces and not incorporated into the crystal lattice, which deserves additional studies to verify this proposal. X-ray diffraction (XRD) analyses of salt crystals confirmed that Na2SO4·10H2O with the structure of thenardite was crystallized. Any other phase was detected. [ABSTRACT FROM AUTHOR]

Adding ionic species can critically affect the structure of weak polyelectrolyte (PE) chains, whose charge density in aqueous solution can be greatly regulated by bathing solution conditions such as pH and added ions. Distinct from simple ions that can be treated as point charges, multivalent macroions of finite size, including many charged nanoparticles and biopolymers, could show strong electrostatic coupling with PEs and effectively modify the conformation and assembly of PEs in aqueous solution. In this work, we have compared the effects of hydrophilic multivalent macroion of finite size and simple divalent ion on the conformational transition of a model weak polybase, poly(2-vinylpyridine) (P2VP), in dilute aqueous solution. By using fluorescence correlation spectroscopy combined with photon counting histogram analysis, we have examined the swollen-to-collapsed conformational transition and local electric potential of a P2VP chain in ionic aqueous solution at a single-molecule level. Adding inorganic polytungstate ([W12]) macroion bearing eight negative charges per [W12] of ~0.8 nm in diameter at increased concentration from 10-9 to 10-5 mM can lead to a shift of the critical conformational transition pH, pHcr, of P2VP to lower pH values, in an opposite trend to the previously reported effect of adding simple monovalent anion. Conversely, adding simple divalent sulfate anion can lead to a nonmonotonic change of pHcr when increasing its concentration from 0.03 to 15 mM. Additionally, at pH < pHcr where P2VP is highly protonated and adopts a swollen conformation, a monotonic decrease of P2VP size is observed with increased sulfate ionic concentration, exhibiting the typical ionic screening effect. In contrast, the size of the P2VP chain shows little change with increasing [W12] concentration before the precipitation of P2VP from water. To investigate the distinct effects of multivalent ion and macroion on the conformational transition of P2VP in aqueous solution, we have also measured the local proton concentration in the vicinity to a P2VP chain by an attached pH-sensitive fluorescence probe. In both cases, we have observed the monotonic reduction of the local electric potential of a swollen P2VP chain with increased ionic concentration, despite the increased protonation degree of P2VP. The results suggest that counterion condensation of multivalent ion and macroion can modify the effective net charge density of P2VP chains in dilute aqueous solution. However, possibly due to its high multivalency and finite size, multivalent [W12] macroion is much more effective in modifying the local electric environment and structure of P2VP chains at 3-7 orders of magnitude lower concentrations than simple sulfate counterion. [ABSTRACT FROM AUTHOR]

Adsorption isotherm-based statistical thermodynamic models can be used to determine solute concentration and solute and solvent activities in aqueous solutions. Recently, the number of adjustable parameters in the isotherm model of Dutcher et al. J. Phys. Chem. A/C 2011, 2012, 2013 were reduced for neutral solutes as well as symmetric 1:1 electrolytes by using a Coulombic model to describe the solute-solvent energy interactions (Ohm et al. J. Phys. Chem. A 2015, Nandy et al. J. Phys. Chem. A 2016). Here, the Coulombic treatment for symmetric electrolytes is extended to establish improved isotherm model equations for asymmetric 1-2 and 1-3 electrolyte systems. The Coulombic model developed here results in prediction of activities and other thermodynamic properties in multicomponent systems containing ions of arbitrary charge. The model is found to accurately calculate the osmotic coefficient over the entire solute concentration range with two model parameters, related to intermolecular solute-solute and solute-solvent spacing. The inorganic salts and acids treated here are generally considered to be fully dissociated. However, there are certain weak acids that do not dissociate completely, such as the bisulfate ion. In this work, partial dissociation of the bisulfate ion from sulfuric acid is treated as a mixture, with an additional model parameter that accounts for the dissociation ratio of the dissociated ions to nondissociated ions. [ABSTRACT FROM AUTHOR]

Schwertmannite is a ferric oxyhydroxysulfate mineral, which is common in acid sulfate systems. Such systems contain varying concentrations of phosphate (PO43-)an essential nutrient whose availability may be coupled to schwertmannite formation and fate. This study examines the effect of phosphate on schwertmannite stability under reducing conditions. Phosphate was added at 0, 80, 400, and 800 μmoles g-1 (i.e., zero, low, medium, and high loading) to schwertmannite suspensions which were inoculated with wetland sediment and suspended in N2-purged artificial groundwater. pH remained between 2.7 and 4.3 over the 41 day experiment duration. Fe(II) accumulated in solution due to dissimilatory Fe(III)-reduction, which was most pronounced at intermediate PO43- loadings (i.e., in the low PO43- treatment). Partial transformation of schwertmannite to goethite occurred in the zero and low PO43- treatments, with negligible transformation in higher PO43- treatments. Overall, the results suggest that intermediate PO43- loadings provide conditions which facilitate optimal reductive dissolution of schwertmannite. At zero PO43- loading, reductive dissolution appears to be constrained by the rapid transformation of schwertmannite to goethite, which thereby decreases the bioavailability of solid-phase Fe(III). Conversely, at high loadings, PO43- appears to stabilize the schwertmannite surface against dissolution; probably via the formation of strong surface complexes. [ABSTRACT FROM AUTHOR]

Hot springs represent a major source of arsenic release into the environment. Speciation is typically reported to be dominated by arsenite, arsenate, and inorganic thiolated arsenates. Much less is known about the relevance and formation of methylated thioarsenates, a group with species of high mobility and toxicity. In hot spring samples taken from the Tengchong volcanic region in China, methylated thioarsenates contributed up to 13% to total arsenic. Enrichment cultures were obtained from the corresponding sediment samples and incubated to assess their capability to convert arsenite into methylated thioarsenates over time and in the presence of different microbial inhibitors. In contrast to observations in other environmental systems (e.g., paddy soils), there was no solid evidence, supporting that the sulfate-reducing bacteria contributed to the arsenic methylation. Methanosarcina , the sole genus of methanogens detected in the enrichment cultures, as well as Methanosarcina thermophila TM-1, a pure strain within the genus, did methylate arsenic. We propose that methylated thioarsenates in a typical sulfide-rich hot spring environment like Tengchong form via a combination of biotic arsenic methylation driven by thermophilic methanogens and arsenic thiolation with either geogenic sulfide or sulfide produced by sulfate-reducing bacteria.

The anti-inflammation effect of aqueous Phyllanthus emblica L. extract (APE) and its possible underlying mechanism in dextran sulfate sodium (DSS)-induced mice chronic colonic inflammation were studied. APE treatment significantly improved the colitic symptoms, including ameliorating the shortening of the colon, increasing the DSS-induced body weight loss, reducing the disease activity index, and reversing the condition of colon tissue damage of mucus lost and goblet cell reduction. Overproduction of serum pro-inflammatory cytokines were suppressed by the treatment of APE. Gut microbiome analysis showed that APE remodeled the structure of gut bacteria in phylum and genus levels, upregulating the abundance of phylum Bacteroidetes, family Muribaculaceae, and genus Bacteroides and downregulating the abundance of phylum Firmicutes. The reshaped gut microbiome caused metabolic functions and pathway change with enhanced queuosine biosynthesis and reduced polyamine synthesis pathway. Colon tissue transcriptome analysis further elucidated APE-inhibited mitogen-activated protein kinase (MAPK), cytokine-cytokine receptor interaction, and tumor necrosis factor (TNF) signaling pathways and the expressions of the genes that promote the progress of colorectal cancer. It turned out that APE reshaped the gut microbiome and inhibited MAPK, cytokine-cytokine receptor interaction, and TNF signaling pathways as well as the colorectal-cancer-related genes to exert its colitis protective effect.

Multiphase oxidation of sulfur dioxide (SO 2 ) by ozone (O 3 ) in alkaline sea salt aerosols is an important source of sulfate aerosols in the marine atmosphere. However, a recently reported low pH of fresh supermicron sea spray aerosols (mainly sea salt) would argue against the importance of this mechanism. Here, we investigated the impact of ionic strength on the kinetics of multiphase oxidation of SO 2 by O 3 in proxies of aqueous acidified sea salt aerosols with buffered pH of ∼4.0 via well-controlled flow tube experiments. We find that the sulfate formation rate for the O 3 oxidation pathway proceeds 7.9 to 233 times faster under high ionic strength conditions of 2-14 mol kg -1 compared to the dilute bulk solutions. The ionic strength effect is likely to sustain the importance of multiphase oxidation of SO 2 by O 3 in sea salt aerosols in the marine atmosphere. Our results indicate that atmospheric models should consider the ionic strength effects on the multiphase oxidation of SO 2 by O 3 in sea salt aerosols to improve the predictions of the sulfate formation rate and the sulfate aerosol budget in the marine atmosphere.

Exploiting cellulose nanocrystals' high aspect ratio and tailorable surface for immunological biosensors has been hindered by the relatively limited research on using commonly available sulfated cellulose nanocrystals (CNCs) for antibody immobilization and by the low hydrolytic stability of dried assemblies produced from sulfated CNCs. Herein, we report a reaction scheme that enables both hydrolytic stability and antibody immobilization through 3-aminopropyl-triethoxysilane and glutaric anhydride chemistry. Immobilization was demonstrated using three model antibodies used in the detection of the cancer biomarkers: alpha-fetoprotein, prostate-specific antigen, and carcinoembryonic antigen. Thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy provided evidence of CNC modification. Quartz crystal microbalance with dissipation monitoring was used to monitor binding during each step of the immobilization scheme as well as binding of the corresponding antigens. The general reaction scheme was tested using both aqueous CNC dispersions and CNC films. Film modification is slightly simpler as it avoids centrifugation and washing steps. However, modifying the dispersed CNCs provides access to their entire surface area and results in a greater capacity for antigen binding.

Polarized transmitted light observation was used to examine the Krafft point temperature of cesium dodecylsulfate (CsDS) in water over a wide range of concentrations. CsDS shows an elevated Krafft temperature compared to that of sodium dodecyl sulfate (SDS). Unlike SDS, the CsDS solubility temperature remains virtually constant at high concentration. Also, the stable birefringent liquid crystal appears at a much lower concentration for CsDS than for SDS, and the concentration window of its coexistence with isotropic micellar solution is broader. [ABSTRACT FROM AUTHOR]

Isoprene epoxydiol (IEPOX), glyoxal, and methylglyoxal are ubiquitous water-soluble organic gases (WSOGs) that partition to aerosol liquid water (ALW) and clouds to form aqueous secondary organic aerosol (aqSOA). Recent laboratory-derived Setschenow (or salting) coefficients suggest glyoxal's potential to form aqSOA is enhanced by high aerosol salt molality, or "salting-in". In the southeastern U.S., aqSOA is responsible for a significant fraction of ambient organic aerosol, and correlates with sulfate mass. However, the mechanistic explanation for this correlation remains elusive, and an assessment of the importance of different WSOGs to aqSOA is currently missing. We employ EPA's CMAQ model to the continental U.S. during the Southern Oxidant and Aerosol Study (SOAS) to compare the potential of glyoxal, methylglyoxal, and IEPOX to partition to ALW, as the initial step toward aqSOA formation. Among these three studied compounds, IEPOX is a dominant contributor, ~72% on average in the continental U.S., to potential aqSOA mass due to Henry's Law constants and molecular weights. Glyoxal contributes significantly, and application of the Setschenow coefficient leads to a greater than 3-fold model domain average increase in glyoxal's aqSOA mass potential. Methylglyoxal is predicted to be a minor contributor. Acid or ammonium - catalyzed ring-opening IEPOX chemistry as well as sulfate-driven ALW and the associated molality may explain positive correlations between SOA and sulfate during SOAS and illustrate ways in which anthropogenic sulfate could regulate biogenic aqSOA formation, ways not presently included in atmospheric models but relevant to development of effective control strategies. [ABSTRACT FROM AUTHOR]

IR spectroscopy of gas-phase ions is proposed to resolve positional isomers of sulfated carbohydrates. Mass spectrometric fingerprints and gas-phase vibrational spectra in the near and mid-IR regions were obtained for sulfated monosaccharides, yielding unambiguous signatures of sulfated isomers. We report the first systematic exploration of the biologically relevant but notoriously challenging deprotonated state in the near IR region. Remarkably, anions displayed very atypical vibrational profiles, which challenge the well-established DFT (Density Functionnal Theory) modeling. The proposed approach was used to elucidate the sulfate patterns in glycosaminoglycans, a ubiquitous class of mammalian carbohydrates, which is regarded as a major challenge in carbohydrate structural analysis. Isomeric glycosaminoglycan disaccharides from heparin and chondroitin sources were resolved, highlighting the potential of infrared multiple photon dissociation spectroscopy as a novel structural tool for carbohydrates. [ABSTRACT FROM AUTHOR]