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A Fe(OTf)3 and γ-cyclodextrin-catalyzed hydroarylation of alkenes with 1-naphthols or 2-naphthols is demonstrated. This efficient and general method delivers a wide range of benzylic naphthols from readily available starting materials with high chemo- and regioselectivity in up to 99% yield, with no need for a strong base or additive. [ABSTRACT FROM AUTHOR]

The two naphthol isomers were investigated in different organic solvents by taking cyclic voltammograms, and fouling took place on a platinum electrode surface, except for dimethyl sulfoxide and dimethyl formamide. Studies in allyl alcohol rarely used in electrochemical investigations pointed to the importance of the carbon–carbon double bond as electrode deactivation was remarkably faster compared with its saturated analog solvent. Similarly, the use of the other unsaturated solvent mesityl oxide in the electropolymerization of naphthols resulted in different findings compared with methyl isobutyl ketone. As dimethyl formamide was the best choice concerning the solubility of products, it was successfully tested in electrode renewal after deactivation in an aqueous solution. The increase in dimethyl formamide content led to more and more improved reproducibility of the currents of the outlined aromatic compounds. Naphthol isomers were assessed in the suppression of layer growth originating from the electrooxidation of another monomer phloroglucinol. Its simultaneous electrooxidation with naphthol monomers had a dramatic effect on layer morphology and it was found that instead of a coherent organic layer originating from the homopolymerization of phloroglucinol, the copolymerization with naphthols led to the development of more porous and rougher deposits. The suppressed electropolymerization thus increased sensitivity towards a chosen redox active compound, 4-methoxyphenol.

The two naphthol isomers were investigated in different organic solvents by taking cyclic voltammograms, and fouling took place on a platinum electrode surface, except for dimethyl sulfoxide and dimethyl formamide. Studies in allyl alcohol rarely used in electrochemical investigations pointed to the importance of the carbon–carbon double bond as electrode deactivation was remarkably faster compared with its saturated analog solvent. Similarly, the use of the other unsaturated solvent mesityl oxide in the electropolymerization of naphthols resulted in different findings compared with methyl isobutyl ketone. As dimethyl formamide was the best choice concerning the solubility of products, it was successfully tested in electrode renewal after deactivation in an aqueous solution. The increase in dimethyl formamide content led to more and more improved reproducibility of the currents of the outlined aromatic compounds. Naphthol isomers were assessed in the suppression of layer growth originating from the electrooxidation of another monomer phloroglucinol. Its simultaneous electrooxidation with naphthol monomers had a dramatic effect on layer morphology and it was found that instead of a coherent organic layer originating from the homopolymerization of phloroglucinol, the copolymerization with naphthols led to the development of more porous and rougher deposits. The suppressed electropolymerization thus increased sensitivity towards a chosen redox active compound, 4-methoxyphenol. [ABSTRACT FROM AUTHOR]

Naphthols (NAPs), commonly used phenolic compounds, have significant impact on environmental risk and human health, necessitating advanced treatment methods for their degradation. In this study, a Ti 4 O 7 reactive electrochemical membrane (REM) was developed for the electrochemical oxidation of NAPs. The Ti 4 O 7 REM presented a porosity of 42.18 ± 2.3% and a median pore diameter of 1.21 µm. High permeability (846 LMH bar−1) was achieved at relatively low transmembrane pressure and resulted in a convection-enhanced rate constant for Fe (CN) 6 4- oxidation of 1.7 × 10−4 m/s. The increase in current density and decrease in plate spacing had a positive influence on NAPs degradation. The TOC removal efficiencies of 1-naphthol (1-NAP) and 2-naphthol (2-NAP) were 68.6% and 63.5%, respectively at the current density of 6 mA/cm2 and plate spacing of 10 mm. Additionally, quantum chemical calculation using density functional theory (DFT) was employed to identify the active sites of NAPs through atom charge and frontier electron density (FED) calculations. Results showed that C14 and C10 were identified as the active sites for 1-NAP, while C9 and C13 were the active sites for 2-NAP. Hydroxyl radical and sulfate radical produced on the electrode surface were the main oxidants for NAPs degradation during the electro-oxidation process. The degradation pathway included hydroxylation, oxygenation, decarbonylation, and ring-open processes, which was in agreement with the theoretical calculations. Furthermore, the quantitative structure-activity relationship (QSAR) predictive model was used to assess the toxicity changes during the electrochemical oxidation process of NAPs, suggesting that the toxicity of intermediates increased at the beginning and significantly reduced at the end. This comprehensive study provides practical and theoretical insights into the application of electrochemical oxidation technique for the reduction of refractory compounds in wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Naphtho[1,8-de][1,2]oxazin-4-ol and its acyl or benzyl derivatives ring open to various 2,8-dihydroxy-1-naphthonitriles, which, through (de)protection protocols and reduction, afford the target (E)-2-hydroxy-8-methoxy-1-naphthaldehyde. This was converted to its corresponding oxime, which was oxidatively o-cyclized with phenyliodine(III) diacetate (PIDA) to 9-methoxynaphtho[1,2-d]isoxazole 2-oxide. The latter, in deuterated DMSO at room temperature, was rearranged to its isomer 2-hydroxy-8-methoxy(naphthalen-1-yl)nitrile oxide. The isomerization was detected by time-course plot 1H NMR spectroscopy and further identified from its 13C NMR and HRMS spectra. The nitrile oxide was stable in (non)deuterated DMSO for at least 18 h. A 3,4-bis(2-hydroxy-8-methoxynaphthalen-1-yl)-1,2,5-oxadiazole 2-oxide, as a dimerization product or an isocyanate as a rearrangement isomer, was ruled out, the former by its HRMS spectrum and the latter by its 1,3-dipolar cycloaddition reactions to substituted isoxazoles. [ABSTRACT FROM AUTHOR]

This article explores the synthesis of spirocyclic cyclohexadienones from hydroquinones and naphthols. The authors discovered that electron-rich hydroquinones and naphthols yielded the desired spiro-cycles in moderate to good yields. They also investigated the reaction's scope using different reactants and found that certain conditions favored the formation of [4+2]-fused ring products, while others favored [4+1]-dearomatization spiroannulation products. The authors proposed a mechanism for the reaction involving sequential Friedel-Crafts reactions and isomerization reactions, but noted that simple substituted phenols did not react under the current conditions. [Extracted from the article]

This article discusses the use of electrochemistry as a sustainable and efficient method for the synthesis of spirooxacyclic compounds, which have biological and medicinal relevance. The authors optimize the reaction conditions and successfully synthesize various compounds with high yields. The reactions involve the formation of cyclic ethers and lactones from phenols and alcohols. The purification and characterization of the compounds are detailed, including their NMR spectra and MS data. The supporting information for the article is available online. [Extracted from the article]

The waste aqueous solutions containing naphthol are treated by physical and chemical methods. However, naphthols are toxic to environment and human health. So it is very important to simultaneously detect them, will make contributions to both the manufacture and the environment management. Herein we developed a simple, cost effective, electrochemical sensor based on magnetite (Fe3O4 nanoparticles) porous reduced graphene oxide/carbon nanotubes (Fe3O4@prGO-CNT) nanocomposite for simultaneous detection of 1-naphthol and 2-naphthol. Voltammetric responses suggest dramatical improvement of electrocatalytic properties of naphthols by incorporating Fe3O4@prGO-CNT on carbon paste electrode (CPE). Differential pulse voltammetric (DPV) measurement depicts large potential separation of about 200 mV between naphthols, allows their simultaneous determination from binary mixture. Under optimized condition, Fe3O4@prGO-CNT/CPE manifested linear relationships of 1-naphthol and 2-naphthol in the range of 0.5–30 and 0.7–40 μM with detection limit (S/N = 3) of 76 and 82 nM respectively. Moreover, Fe3O4@prGO-CNT/CPE showed satisfactory response towards wastewaters and river waters for determining 1-naphthol and 2-naphthol concentrations. [ABSTRACT FROM AUTHOR]

The excessive use of carbaryl has resulted in the risk of its exposure. In this study, we isolated six nanobodies (Nbs) from a camelid phage display library against the biomarker of carbaryl, 1-naphthol (1-NAP). Owing to its characteristics of easy genetic modifications, we produced a nanobody-alkaline phosphatase (Nb-CC4-ALP) fusion protein with good stability. A dual-emission system based ratiometric fluoroimmunoassay (RFIA) for quick and highly sensitive determination of 1-NAP was developed. Silicon nanoparticles (SiNPs) was used as an internal reference and for aggregation-induced emission enhancement (AIEE) of gold nanoclusters (AuNCs), while AuNCs could be quenched by MnO2 via oxidation. In the presence of ALP, ascorbic acid phosphate (AAP) can be transformed into ascorbic acid (AA), the later can etch MnO2 to recover the fluorescence of the AuNCs. Based on optimal conditions, the proposed assay showed 220-fold sensitivity improvement in comparison with conventional monoclonal antibody-based ELISA. The recovery test of urine samples and the validation by standard HPLC-FLD demonstrated the proposed assay was an ideal tool for screening 1-NAP and provided technical support for the monitoring of carbaryl exposure.

Herein, we report an unprecedented one-pot domino synthesis of indole- or naphthol-tethered biologically relevant 4H-chromene derivatives from readily accessible salicylaldehydes, malononitrile, and indoles/β-naphthols employing efficient, inexpensive, non-metallic Benzyltrimethylammonium hydroxide (Triton B) as a base promoter. This protocol is an atom-economic three-component one-pot reaction that delivers various 4H-chromenes with good substrate scope and excellent yields. Moreover, this protocol compares the synthesis of 4H- chromene derivatives with the earlier reported 2H-chromenes avoiding the time and solvent-consuming tedious column chromatography.

In this study, we present a straightforward and environmentally friendly electrochemical approach for achieving selective halogenation of N‐heteroarenes, including indoles, diazoles, pyrroles, quinolinone, and naphthols. Our method utilizes commercially available and affordable ammonium halides as halogen source. A library of valuable halogenated N‐heteroarenes can be synthesized in moderate to excellent yields under mild conditions (transition‐metal‐free, oxidant‐free, ethanol as solvent, atmospheric environment). The approach demonstrates a broad substrate scope, excellent tolerance towards various functional groups, and scalability. [ABSTRACT FROM AUTHOR]

Ecological diversity in fungi is largely defined by metabolic traits, including the ability to produce secondary or "specialized" metabolites (SMs) that mediate interactions with other organisms. Fungal SM pathways are frequently encoded in biosynthetic gene clusters (BGCs), which facilitate the identification and characterization of metabolic pathways. Variation in BGC composition reflects the diversity of their SM products. Recent studies have documented surprising diversity of BGC repertoires among isolates of the same fungal species, yet little is known about how this population-level variation is inherited across macroevolutionary timescales. Here, we applied a novel linkage-based algorithm to reveal previously unexplored dimensions of diversity in BGC composition, distribution, and repertoire across 101 species of Dothideomycetes, which are considered the most phylogenetically diverse class of fungi and known to produce many SMs. We predicted both complementary and overlapping sets of clustered genes compared with existing methods and identified novel gene pairs that associate with known secondary metabolite genes. We found that variation among sets of BGCs in individual genomes is due to nonoverlapping BGC combinations and that several BGCs have biased ecological distributions, consistent with niche-specific selection. We observed that total BGC diversity scales linearly with increasing repertoire size, suggesting that secondary metabolites have little structural redundancy in individual fungi. We project that there is substantial unsampled BGC diversity across specific families of Dothideomycetes, which will provide a roadmap for future sampling efforts. Our approach and findings lend new insight into how BGC diversity is generated and maintained across an entire fungal taxonomic class.

1-naphthol (1-NAP) is the main metabolite of pesticide carbaryl and naphthalene, and is also a genotoxic and carcinogenic intermediate in the synthesis of organic compound, dyes, pigment and pharmaceutical industry. In this work, two novel haptens were designed and synthesized for developing a competitive indirect enzyme-linked immunosorbent assay (ciELISA) method for 1-NAP in urine samples. The assay showed a limit of detection of 2.21 ng/mL and working range from 4.02 ng/mL to 31.25 ng/mL for 1-NAP in optimized working buffer. The matrix effect of samples was eliminated via 15-fold dilution of optimized working buffer. Good average recoveries (102.4%-123.4%) with a coefficient of variation from 11.7% to 14.7% was obtained for spiked urine samples. Subsequent instrument verification test showed good correlation between the results of ciELISA and high-performance liquid chromatography. The developed ciELISA is a high-throughput tool to monitor 1-NAP in urine, which can provide technical support for the establishment of biological exposure level for the exposure to carbaryl, naphthalene and other related pollutants.

Naphtho[1,8-de][1,2]oxazin-4-ol and its acyl or benzyl derivatives ring open to various 2,8-dihydroxy-1-naphthonitriles, which, through (de)protection protocols and reduction, afford the target (E)-2-hydroxy-8-methoxy-1-naphthaldehyde. This was converted to its corresponding oxime, which was oxidatively o-cyclized with phenyliodine(III) diacetate (PIDA) to 9-methoxynaphtho[1,2-d]isoxazole 2-oxide. The latter, in deuterated DMSO at room temperature, was rearranged to its isomer 2-hydroxy-8-methoxy(naphthalen-1-yl)nitrile oxide. The isomerization was detected by time-course plot 1H NMR spectroscopy and further identified from its 13C NMR and HRMS spectra. The nitrile oxide was stable in (non)deuterated DMSO for at least 18 h. A 3,4-bis(2-hydroxy-8-methoxynaphthalen-1-yl)-1,2,5-oxadiazole 2-oxide, as a dimerization product or an isocyanate as a rearrangement isomer, was ruled out, the former by its HRMS spectrum and the latter by its 1,3-dipolar cycloaddition reactions to substituted isoxazoles.

Natural product discovery in the microbial world has historically been biased toward aerobes. Recent in silico analysis demonstrates that genomes of anaerobes encode unexpected biosynthetic potential for natural products, however, chemical data on natural products from the anaerobic world are extremely limited. Here, we review the current body of work on natural products isolated from strictly anaerobic microbes, including recent genome mining efforts to discover polyketides and non-ribosomal peptides from anaerobes. These known natural products of anaerobes have demonstrated interesting molecular scaffolds, biosynthetic logic, and/or biological activities, making anaerobes a promising reservoir for future natural product discovery.

The aromatic C(sp2)-H functionalization of unprotected naphthols with α-phenyl-α-diazoesters under mild conditions catalyzed by CuCl and CuCl2 exhibits high efficiency and unique ortho-selectivity. In this study, the combination of density functional theory (DFT) calculations and experiments is employed to investigate the mechanism of C-H functionalization, which reveals the fundamental origin of the site-selectivity. It explains that CuCl-catalyzed ortho-selective C-H functionlization is due to the bimetallic carbene, which differs from the reaction catalyzed by CuCl2 via monometallic carbene. The results demonstrate the function of favourable H-bond interactions on the site- and chemo-selectivity of reaction through stabilizing the rate-determining transition states in proton (1,3)-migration. [ABSTRACT FROM AUTHOR]

In the present research, the coconut endocarp shell as a natural waste was converted into a valuable non-conventional catalyst by a simple thermal treatment, namely coconut endocarp shell ash (CESA). The prepared CESA was characterized using several analytical techniques, including TGA, FT-IR, XRD, BET, SEM, and EDX. The catalytic property of the CESA was examined in the synthesis of pharmaceutically active 2-amino-4H-benzochromene derivatives via one-pot three-component condensation of aldehydes, malononitrile, and α or β-naphthol in ethanol at room temperature. The most promising aspects of the presented approach are the high catalytic efficiency, short reaction time, excellent yield of products, operational simplicity, waste to wealth, and optimization with the design of experiment. Moreover, the CESA catalyst was recycled five times without any apparent loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metal-free. • C H functionalization. • Good functional group tolerance. • Multistep cascade reaction. The efficient synthesis of sulfonated naphthols was realized by dehydroaromatization of β-tetralones with sodium sulfinates under metal-free conditions. Iodine-containing reagents played an important role in this oxidative coupling process. Sodium sulfinates served as a stable and readily available sulfur source, providing sulfones in good to excellent yields. A wide range of functional groups were well tolerated in this reaction. [ABSTRACT FROM AUTHOR]

The naphterpins and marinones are naphthoquinone meroterpenoids with an unusual aromatic oxidation pattern that is biosynthesized from 1,3,6,8-tetrahydroxynaphthalene (THN). We propose that cryptic halogenation of THN derivatives by vanadium-dependent chloroperoxidase (VCPO) enzymes is key to this biosynthetic pathway, despite the absence of chlorine in these natural products. This speculation inspired a total synthesis to mimic the naphterpin/marinone biosynthetic pathway. In validation of this biogenetic hypothesis, two VCPOs were discovered that interconvert several of the proposed biosynthetic intermediates.

Five new naphthalenones, two enantiomers (−)-1 and (+)-1 leptothalenone A, (−)-4,8-dihydroxy-7-(2-hydroxy-ethyl)-6-methoxy-3,4-dihydro-2H-naphthalen-1-one ((−)-2), (4S, 10R, 4’S)-leptotha-lenone B (5), (4R, 10S, 4’S)-leptothalenone B (6), and a new isocoumarine, 6-hydroxy-5,8-dimethoxy-3-methyl-1H-isochromen-1-one (4), along with two known compounds (+)-4,8-dihydroxy-7-(2-hydroxy-ethyl)-6-methoxy-3,4-dihydro-2H-naphthalen-1-one ((+)-2) and (+)-10-norparvulenone (3) were isolated from the marine-derived fungus Leptosphaerulina chartarum 3608. The structures of new compounds were elucidated by HR-ESIMS, NMR, and ECD analysis. All compounds were evaluated for cytotoxicity and anti-inflammatory activity. Compound 6 showed moderate anti-inflammatory activity by inhibiting the production of nitric oxide (NO) in lipopolysaccharide-stimulated RAW264.7 cells, with an IC50 value of 44.5 μM.

Prenyl modification often improves the biological activities of compounds. Prenyltransferases have attracted attention as environmentally friendly biocatalysts for catalyzing prenyl modification of compounds. Compared to dimethylallyl modifications, research on geranyl modifications is relatively limited. To enrich biocatalytic toolboxes for generating potentially bioactive geranylated derivatives, this study developed methodologies to synthesize two types of geranylated compounds, i.e., geranylated tryptophan-containing cyclic dipeptides and geranylated naphthols, employing the F253G mutant of CdpC3PT, a cyclic dipeptide prenyltransferase from Neosartorya fischeri. The cyclic dipeptides (1-3) were transformed into C7-geranylated products (1G1-3G1), whereas 1-naphthol (4) and derivatives (5-6) yielded C4-geranylated products (4G1-6G1) and 2,7-dihydroxynaphthalene (7) generated a C3-geranylated product (7G1). All seven substrates and their geranylated products underwent antibacterial efficacy testing against Bacillus subtilis. Among them, five geranylated compounds (2G1 and 4G1-7G1) demonstrated antibacterial efficacies against Bacillus subtilis, with MIC values ranging from 4 to 32 μg/mL, surpassing their non-geranylated precursors. This research broadens the tools of geranyl-modifying biocatalysts, illustrates a case for developing highly efficient or function-altered biocatalysts and showcases the potential of prenyltransferases in the biosynthesis of bioactive small molecules., (© 2024 Wiley‐VCH GmbH.)

Cyanobacterial blooms are common events that releases secondary metabolites into water posing considerable threats to the environment, wildlife, and public health. Some of these metabolites, such as microcystin, have been extensively studied and associated with harmful effects in mammals and aquatic organisms, while the biological effects of others, like geosmin, remain much less investigated. Enhancing our understanding of cyanotoxins effects on organisms is especially relevant facing the complex scenarios projected due to global warming. The aim of this study was to assess the transcriptional modulation in whole zebrafish (Danio rerio) larvae (n = 9) in response to a 7-days immersion exposure to 3 μg L -1 MCLR or 5 μg L -1 geosmin. No mortality or differences in length gain were observed in zebrafish larvae exposed to environmentally realistic doses of both cyanotoxins. The exposure to MCLR and to geosmin caused the differential expression of 164 and 172 genes respectively, being 23 upregulated by MCLR and 98 upregulated by geosmin. Among the upregulated genes, 16 were shared, while 42 were shared among the downregulated genes. Over-representation analysis identified three enriched GO terms only among the genes upregulated by geosmin: organic hydroxy compound metabolic process (1901615), small molecule biosynthetic process (0044283), and lipid metabolic process (0006629). In fact, the expression of 12 of the 13 genes directly involved in the synthesis of cholesterol from acetyl-CoA was upregulated by geosmin. A chronic upregulation of cholesterol biosynthetic pathway is linked to several diseases and metabolic disorders, including alterations in sex-related hormones. Moreover, our results indicate that geosmin and MCLR acts through different mechanisms. Geosmin does not appear to provoke short-term adverse effects as MCLR but could disrupt the endocrine system by altering the lipid and steroid metabolism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Alternaria infectoria causes opportunistic human infections and is a source of allergens leading to respiratory allergies. In this work, we prepared cell wall nanoparticles (CWNPs) as a novel approach to study macrophage immunomodulation by fungal hyphal cell walls. A. infectoria was grown in the presence of caspofungin, an inhibitor of β(1,3)-glucan synthesis; nikkomycin Z, an inhibitor of chitin synthases; and pyroquilon, an inhibitor of dihydroxynaphthalene (DHN)-melanin synthesis. Distinct CWNPs were obtained from these cultures, referred to as casCWNPs, nkCWNPs, and pyrCWNPs, respectively. CWNPs are round-shaped particles with a diameter of 70-200 nm diameter particles that when added to macrophages are taken up by membrane ruffling. CWNPs with no DHN-melanin and more glucan (pyrCWNPs) caused early macrophage activation and lowest viability, with the cells exhibiting ultrastructural modifications such as higher vacuolization and formation of autophagy-like structures. CasCWNPs promoted the highest tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) increase, also resulting in the release of partially degraded chitin, an aspect never observed in macrophage-like cells and fungi. After 6 h of interaction with CWNPs, only half were viable, except with control CWNPs. Overall, this work indicates that compounds that modify the fungal cell wall led to CWNPs with new properties that may have implications for the effects of drugs during antifungal therapy. CWNPs provide a new tool to study the interaction of hyphal fungal cell wall components with phagocytic cells and enable to show how the modification of cell wall components in A. infectoria can modulate the response by macrophages.IMPORTANCE Alternaria species are ubiquitous environmental fungi to which the human host can continuously be exposed, through the inhalation of fungal spores but also of fragments of hyphae, from desegregated mycelia. These fungi are involved in hypersensitization and severe respiratory allergies, such as asthma, and can cause opportunistic infections in immunodepressed human host leading to severe disease. The first fungal structures to interact with the host cells are the cell wall components, and their modulation leads to differential immune responses. Here, we show that fungal cells grown with cell wall inhibitors led to cell wall nanoparticles with new properties in their interaction with macrophages. With this strategy, we overcame the limitation of in vitro assays interacting with filamentous fungi and showed that the absence of DNH-melanin leads to higher virulence, while caspofungin leads to cells walls that trigger higher hydrolysis of chitin and higher production of cytokines., Competing Interests: The authors declare no conflict of interest.

Numerous reservoirs encounter challenges related to taste and odor issues, often attributed to odorous compounds such as geosmin (GSM) and 2-methylisoborneol (2-MIB). In this study, two large reservoirs located in northern and southern China were investigated. The Jinpen (JP) reservoir had 45.99 % Actinomycetes and 14.82 % Cyanobacteria, while the Xikeng (XK) reservoir contained 37.55 % Actinomycetes and 48.27 % Cyanobacteria. Most of the 2-MIB produced in surface layers of the two reservoirs in summer originated from Cyanobacteria, most of the 2-MIB produced in winter and in the bottom water originated from Actinomycetes. Mic gene abundance in the XK reservoir reached 5.42 × 10 4 copies/L in winter. The abundance of GSM synthase was notably high in the bottom layer and sediment of both reservoirs, while 2-MIB synthase was abundant in the surface layer of the XK reservoir, echoing the patterns observed in mic gene abundance. The abundance of odor-producing enzymes in the two reservoirs was inhibited by total nitrogen, temperature significantly influenced Actinomycetes abundance in the JP reservoir, whereas dissolved oxygen had a greater impact in the XK reservoir. Overall, this study elucidates the molecular mechanisms underlying odor compounding, providing essential guidance for water quality management strategies and the improvement of urban water reservoir quality., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The presence of actinobacteria in reservoirs can lead to taste and odor issues, posing potential risks to the safety of drinking water supply. However, the response of actinobacterial communities to environmental factors in drinking water reservoirs remains largely unexplored. To address this gap, this study investigated the community structure and metabolic characteristics of odor-producing actinobacteria in water reservoirs across northern and southern China. The findings revealed differences in the actinobacterial composition across the reservoirs, with Mycobacterium sp. and Candidatus Nanopelagicus being the most prevalent genera. Notably, water temperature, nutrient levels, and metal concentrations were associated with differences in actinobacterial communities, with stochastic processes playing a major role in shaping the community assembly. In addition, three strains of odor-producing actinobacteria were cultured in raw reservoir water, namely Streptomyces antibioticus LJH21, Streptomyces sp. ZEU13, and Streptomyces sp. PQK19, with peak ATP concentrations of 51 nmol/L, 66 nmol/L, and 70 nmol/L, respectively, indicating that odor-producing actinobacteria could remain metabolically active under poor nutrient pressure. Additionally, Streptomyces antibioticus LJH21 produced the highest concentration of geosmin at 24.4 ng/L. These findings enhance our understanding of regional variances and reproductive metabolic mechanisms of actinobacteria in drinking water reservoirs, providing a solid foundation for improving drinking water quality control, especially for taste and odor., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Protozoan parasites infect and kill millions of people worldwide every year, particularly in developing countries where access to clean fresh water is limited. Among the most common are intestinal parasites, including Giardia lamblia and Entamoeba histolytica. These parasites wreak havoc on the epithelium lining the small intestines (G. lamblia) and colon (E. histolytica) causing giardiasis and amebiasis, respectively. In addition, there are less common but far more deadly pathogens such as Naegleria fowleri that thrive in warm waters and infect the central nervous systems of their victims via the nasal passages. Despite their prevalence and associated high mortality rates, there remains an unmet need to identify more effective therapeutics for people infected with these opportunistic parasites. To address this unmet need, we have surveyed plants and traditional herbal medicines known throughout the world to identify novel antiparasitic agents with activity against G. lamblia, E. histolytica, and N. fowleri. Herein, we report Larrea tridentata, known as creosote bush, as a novel source for secondary metabolites that display antiparasitic activity against all three pathogens. This report also characterizes the lignan compound classes, nordihydroguairetic acid and demethoxyisoguaiacin, as novel antiparasitic lead agents to further develop more effective drug therapy options for millions of people worldwide.

1,4-Dihydroxy-2-naphthoic acid (1,4-DHNA) is a bacterial-derived metabolite that binds the aryl hydrocarbon receptor (AhR) and exhibits anti-inflammatory activity in the gut. The structure-dependent AhR activity of hydroxyl/carboxy-substituted naphthoic acids (NAs) was determined in young adult mouse colonic (YAMC) cells and human Caco2 colon cancer cells using CYP1A1/CYP1B1 mRNAs as Ah-responsive genes. Compounds used in this study include 1,4-, 3,5-, and 3,7-DHNA, 1,4-dimethoxy-2-naphthoic acid (1,4-DMNA), 1- and 4-hydroxy-2-naphthoic acid (1-HNA, 4-HNA), 1- and 2-naphthoic acid (1-NA, 2-NA), and 1- and 2-naphthol (1-NOH, 2-NOH). 1,4-DHNA was the most potent compound among hydroxyl/carboxy naphthalene derivatives, and the fold induction response for CYP1A1 and CYP1B1 was similar to that observed for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in YAMC and Caco2 cells. 1- and 4-HNA were less potent than 1,4-DHNA but induced maximal (TCDD-like) response for CYP1B1 (both cell lines) and CYP1A1 (Caco2 cells). With the exception of 1- and 2-NA, all compounds significantly induced Cyp1b1 in YAMC cells and these responses were not observed in AhR-deficient YAMC cells generated using CRISPR/Cas9 technology. In addition, we also observed that 1- and 2-NOH (and 1,4-DHNA) were weak AhR agonists, and 1- and 2-NOH also exhibited partial AhR antagonist activity. Structure-activity relationship studies for CYP1A1 but not CYP1B1 were similar in both cell lines, and CYP1A1 induction required one or both 1,4-dihydroxy substituents and activity was significantly enhanced by the 2-carboxyl group. We also used computational analysis to show that 1,4-DHNA and TCDD share similar interactions within the AhR binding pocket and differ primarily due to the negatively charged group of 1,4-DHNA.

Black fungi on rock surfaces endure a spectrum of abiotic stresses, including UV radiation. Their ability to tolerate extreme conditions is attributed to the convergent evolution of adaptive traits, primarily highly melanized cell walls. However, studies on fungal melanins have not provided univocal results on their photoprotective functions. Here, we investigated whether the black fungi Knufia petricola and Cryomyces antarcticus only use DHN melanin or may employ alternative mechanisms to counteract UV-induced damage. For this, melanized wild types and non-melanized Δpks1 mutants were exposed to different doses of UV-B (312 nm) followed by incubation in constant darkness or in light-dark cycles to allow light-dependent DNA repair by photolyases (photoreactivation). C. antarcticus could tolerate higher UV-B doses but was sensitive to white light, whereas K. petricola showed the opposite trend. DHN melanin provided UV-B protection in C. antarcticus, whereas the same pigment or even carotenoids proved ineffective in K. petricola. Both fungi demonstrated functional photoreactivation in agreement with the presence of photolyase-encoding genes. Our findings reveal that although the adaptive trait of DHN melanization commonly occurs across black fungi, it is not equally functional and that there are species-specific adaptations towards either UV-induced lesion avoidance or repair strategies., (© 2024 The Author(s). Environmental Microbiology Reports published by John Wiley & Sons Ltd.)

Transcription factor Cmr1 (Colletotrichum melanin regulation 1) and its homologs in several plant fungal pathogens are the regulators of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis pathway and have evolved functional diversification in morphology and pathogenicity. The fungal genus Alternaria comprises the group of "black fungi" that are rich in DHN-melanin in the primary cell wall and septa of the conidia. Some Alternaria species cause many economically important plant diseases worldwide. However, the evolution and function of Cmr1 homologs in Alternaria remain poorly understood. Here, we identified a total of forty-two Cmr1 homologs from forty-two Alternaria spp. and all contained one additional diverse fungal specific transcription factor motif. Phylogenetic analysis indicated the division of these homologs into five major clades and three branches. Dated phylogeny showed the A and D clades diverged latest and earliest, respectively. Molecular evolutionary analyses revealed that three amino acid sites of Cmr1 homologs in Alternaria were the targets of positive selection. Asmr1, the homolog of Cmr1 in the potato early blight pathogen, Alternaria solani was amplified and displayed the sequence conservation at the amino acid level in different A. solani isolates. Asmr1 was further confirmed to have the transcriptional activation activity and was upregulated during the early stage of potato infection. Deletion of asmr1 led to the decreased melanin content and pathogenicity, deformed conidial morphology, and responses to cell wall and fungicide stresses in A. solani. These results suggest positive selection and functional divergence have played a role in the evolution of Cmr1 homologs in Alternaria. KEY POINTS: • Cmr1 homologs were under positive selection in Alternaria species • Asmr1 is a functional transcription factor, involved in spore development, melanin biosynthesis, pathogenicity, and responses to cell wall and fungicide stresses in A. solani • Cmr1 might be used as a potential taxonomic marker of the genus Alternaria., (© 2024. The Author(s).)

The dearomatization of 2‐naphthols represents a simple method for the construction of complex 3D structures from simple planar starting materials. We describe a cyclopropanation of 2‐naphthols that proceeds via cyclopropene ring‐opening using rhodium and acid catalysis under mild conditions. The vinyl cyclopropane molecules were formed with high chemoselectivity and scalability, which could be further functionalized at different sites. Both computational and experimental evidence were used to elucidate the reaction mechanism. [ABSTRACT FROM AUTHOR]

An efficient and practical method for the synthesis of aromatic esters from aryl acyl peroxides and phenols, naphthols or 3-hydroxypyridines at room temperature was realized. A series of aromatic esters were synthesized in high yields and with excellent selectivity in the presence of 1,4-diaza[2.2.2]bicyclooctane (DABCO) without the use of transition-metals or acid catalysts. This operation is simple, and it has a good compatibility with various functional groups, especially with heterocyclic pyridine substrates. [ABSTRACT FROM AUTHOR]

A series of monoazo disperse dyes were synthesized by coupling diazotized 4-amino-N-dodecyl-1,8-naphthalimide with N,N-dialkyl anilines and naphthol derivatives. The synthesized intermediates and the dyes were characterized using FTIR, 1H-NMR, 13C-NMR, mass spectroscopy and elemental analysis (CHN). Visible absorption spectra of the dyes were examined in solvents of different polarities. The electronic absorption spectra cover a wavelength (λmax) range of 515-535 nm in DMF at uniformly absorption intensity between 1.59-3.00×104 L mol-1 cm-1. The dyes gave deep and bright intense hues of light violet, maroon, pink and neon red on polyester fabrics. The dyes generally showed good washing and perspiration rating but poor to moderate light fastness properties on woven polyester fabric and could be recommended for commercial outlets.

The aromatic C(sp2)-H functionalization of unprotected naphthols with α-phenyl-α-diazoesters under mild conditions catalyzed by CuCl and CuCl2 exhibits high efficiency and unique ortho-selectivity. In this study, the combination of density functional theory (DFT) calculations and experiments is employed to investigate the mechanism of C-H functionalization, which reveals the fundamental origin of the site-selectivity. It explains that CuCl-catalyzed ortho-selective C-H functionlization is due to the bimetallic carbene, which differs from the reaction catalyzed by CuCl2 via monometallic carbene. The results demonstrate the function of favourable H-bond interactions on the site- and chemo-selectivity of reaction through stabilizing the rate-determining transition states in proton (1,3)-migration.

Multifunctional single-atom catalysts (SACs) have been extensively investigated as outstanding signal amplifiers in bioanalysis field. Herein, a type of Fe single-atom catalysts with Fe-nitrogen coordination sites in nitrogen-doped carbon (Fe-N/C SACs) was synthesized and demonstrated to possess both catalase and peroxidase-like activity. Utilizing Fe-N/C SACs as dual signal amplifier, an efficient bipolar electrode (BPE)-based electrochemiluminescence (ECL) immunoassay was presented for determination of prostate-specific antigen (PSA). The cathode pole of the BPE-ECL platform modified with Fe-N/C SACs is served as the sensing side and luminol at the anode as signal output side. Fe-N/C SACs could catalyze decomposition of H 2 O 2 via their high catalase-like activity and then increase the Faraday current, which can boost the ECL of luminol due to the electroneutrality in a closed BPE system. Meanwhile, in the presence of the target, glucose oxidase (GOx)-Au NPs-Ab 2 was introduced through specific immunoreaction, which catalyzes the formation of H 2 O 2 . Subsequently, Fe-N/C SACs with peroxidase-like activity catalyze the reaction of H 2 O 2 and 4-chloro-1-naphthol (4-CN) to generate insoluble precipitates, which hinders electron transfer and then inhibits the ECL at the anode. Thus, dual signal amplification of Fe-N/C SACs was achieved by increasing the initial ECL and inhibiting the ECL in the presence of target. The assay exhibits sensitive detection of PSA linearly from 1.0 pg/mL to 100 ng/mL with a detection limit of 0.62 pg/mL. The work demonstrated a new ECL enhancement strategy of SACs via BPE system and expands the application of SACs in bioanalysis field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Aging is one of the most important public health issues. Previous studies on the factors affecting aging focused on genetics and lifestyle, but the association between polycyclic aromatic hydrocarbons (PAHs) and aging is still unclear., Methods: This study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2003-2010. A total of 8,100 participants was used to construct the biological age predictors by using recent advanced algorithms Klemera-Doubal method (KDM) and Mahalanobis distance. Two biological aging indexes, recorded as KDM-BA acceleration and PhenoAge acceleration, were used to investigate the relationship between single PAHs and biological age using a multiple linear regression analysis, and a weighted quantile sum (WQS) model was constructed to explore the mixed effects of PAHs on biological age. Finally, we constructed the restricted cubic spline (RCS) model to assess the non-linear relationship between PAHs and biological age., Results: Exposure to PAHs was associated with PhenoAge acceleration. Each unit increase in the log10-transformed level of 1-naphthol, 2-naphthol, and 2-fluorene was associated with a 0.173 (95% CI: 0.085, 0.261), 0.310 (95% CI: 0.182, 0.438), and 0.454 (95% CI: 0.309, 0.598) -year increase in PhenoAge acceleration, respectively (all corrected P < 0.05). The urinary PAH mixture was relevant to KDM-BA acceleration (β = 0.13, 95% CI: 0, 0.26, P = 0.048) and PhenoAge acceleration (β = 0.59, 95% CI: 0.47, 0.70, P < 0.001), and 2-naphthol had the highest weight in the weighted quantile sum (WQS) regression. The RCS analyses showed a non-linear association between 2-naphthol and 2-fluorene with KDM-BA acceleration (all P < 0.05) in addition to a non-linear association between 1-naphthol, 2-naphthol, 3-fluorene, 2-fluorene, and 1-pyrene with PhenoAge acceleration (all P < 0.05)., Conclusion: Exposure to mixed PAHs is associated with increased aging, with 2-naphthol being a key component of PAHs associated with aging. This study has identified risk factors in terms of PAH components for aging., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Fu, Zhang, Zhong, Gao and Yan.)

Early detection of insecticide resistance is essential to develop resistance countermeasures and depends on accurate and rapid biological and biochemical tests to monitor resistance and detect associated mechanisms. Many such studies have measured activities of esterases, enzymes associated with resistance to ester- containing insecticides, using the model substrate, α-naphthyl acetate (α-NA). However, in the field, pests are exposed to ester-containing insecticides such as malathion, that are structurally distinct from α-NA. In the current study, malathion resistance in C. quinquefasciatus (3.2- to 10.4-fold) was highly associated with esterase activity measured with either α-NA (R 2  = 0.92) or malathion (R 2  = 0.90). In addition, genes encoding two esterases (i.e., EST-2 and EST-3) were over-expressed in field- collected strains, but only one (EST-3) was correlated with malathion hydrolysis (R 2  = 0.94) and resistance (Rs = 0.96). These results suggest that, in the strains studied, α-NA is a valid surrogate for measuring malathion hydrolysis, and that heightened expression of an esterase gene is not necessarily associated with metabolic resistance to insecticidal esters., (Copyright © 2024. Published by Elsevier Inc.)

The sensory quality of drinking water, and particularly its taste and odor (T&O) is a key determinant of consumer acceptability, as consumers evaluate water by their senses. Some of the conventional treatment processes to control compounds which impart unpleasant T&O have limitations because of their low efficiency and/or high costs. Therefore, there is a great need to develop an effective process for removing T&O compounds without secondary concerns. The primary objective of this study was to assess for the first time the effectiveness of spirulina-based carbon materials in removing geosmin (GSM) and 2-methylisoborneol (2-MIB) from water, two commonly occurring natural T&O compounds. The efficiency of the materials to remove environmentally relevant concentrations of GSM and 2-MIB (ng L -1 ) from ultrapure and raw water was investigated using a sensitive headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC/MS) method. Moreover, the genotoxic and cytotoxic effects of the spirulina-based materials were assessed for the first time to evaluate their safety and their potential in the treatment of water for human consumption. Based on the results, spirulina-based materials were found to be promising for drinking water treatment applications, as they did not exert geno-cytotoxic effects on human cells, while presenting high efficiency in removing GSM and 2-MIB from water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

We have developed an efficient chalcogenylation of electron-rich naphthalene derivatives catalyzed by FeCl3 and KI. The methodology provides access to several nonsymmetrical diorganoyl chalcogenides (S, Se) by selective C1 chalcogenylation of 2-naphthols or 2-naphthylamines using simple and cheap catalysts. Several control experiments supported the hypothesis that a redox reaction between Fe(III) and KI produces I2 , which catalyzed the chalcogenylation. [ABSTRACT FROM AUTHOR]

The chiral H 8 -BINOL derivatives R- 1 and R- 2 were efficiently synthesized via a Suzuki coupling reaction, and they can be used as novel dialdehyde fluorescent probes for the enantioselective recognition of R/S-2-amino-1-phenylethanol. In addition, R- 1 is much more effective than R- 2 . Scanning electron microscope images and X-ray analyses show that R- 1 can form supramolecular vesicles through the self-assembly effect of the π-π force and strong hydrogen bonding. As determined via analysis, the fluorescence of the probe was significantly enhanced by mixing a small amount of S-2-amino-1-phenylethanol into R- 1 , with a redshift of 38 nm, whereas no significant fluorescence response was observed in R-2-amino-1-phenylethanol. The enantioselective identification of S-2-amino-1-phenylethanol by the probe R- 1 was further investigated through nuclear magnetic titration and fluorescence kinetic experiments and DFT calculations. The results showed that this mechanism was not only a simple reactive probe but also realized object recognition through an ICT mechanism. As the intramolecular hydrogen bond activated the carbonyl group on the probe R- 1 , the carbonyl carbon atom became positively charged. As a strong nucleophile, the amino group of S-2-amino-1-phenylethanol first transferred the amino electrons to a carbonyl carbocation, resulting in a significantly enhanced fluorescence of the probe R- 1 and a 38 nm redshift. Similarly, S-2-amino-1-phenylethanol alone caused severe damage to the self-assembled vesicle structure of the probe molecule itself due to its spatial structure, which made R- 1 highly enantioselective towards it., Competing Interests: The authors declare no conflicts of interest.

Freshwater benthic algae form complex mat matrices that can confer ecosystem benefits but also produce harmful cyanotoxins and nuisance taste-and-odor (T&O) compounds. Despite intensive study of the response of pelagic systems to anthropogenic change, the environmental factors controlling toxin presence in benthic mats remain uncertain. Here, we present a unique dataset from a rapidly urbanizing community (Kansas City, USA) that spans environmental, toxicological, taxonomic, and genomic indicators to identify the prevalence of three cyanotoxins (microcystin, anatoxin-a, and saxitoxin) and two T&O compounds (geosmin and 2-methylisoborneol). Thereafter, we construct a random forest model informed by game theory to assess underlying drivers. Microcystin (11.9 ± 11.6 µg/m 2 ), a liver toxin linked to animal fatalities, and geosmin (0.67 ± 0.67 µg/m 2 ), a costly-to-treat malodorous compound, were the most abundant compounds and were present in 100 % of samples, irrespective of land use or environmental conditions. Anatoxin-a (8.1 ± 11.6 µg/m 2 ) and saxitoxin (0.18 ± 0.39 µg/m 2 ), while not always detected, showed a systematic tradeoff in their relative importance with season, an observation not previously reported in the literature. Our model indicates that microcystin concentrations were greatest where microcystin-producing genes were present, whereas geosmin concentrations were high in the absence of geosmin-producing genes. Together, these results suggest that benthic mats produce microcystin in situ but that geosmin production may occur ex situ with its presence in mats attributable to adsorption by organic matter. Our study broadens the awareness of benthic cyanobacteria as a source of harmful and nuisance metabolites and highlights the importance of benthic monitoring for sustaining water quality standards in rivers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

2-Methylisoborneol (2-MIB) and geosmin are compounds released by algae that significantly degrade reservoir water quality, posing a threat to both the safety of drinking water and the quality of aquatic products sourced from these environments. However, few studies have explored how enhanced thermal stratification affects the occurrence and regulation of odorants in large drinking water reservoirs. Through systematic monitoring and investigation of Xin'anjiang Reservoir, we found that enhanced thermal stratification promotes filamentous cyanobacteria, particularly Leptolyngbya sp., as the primary contributor to 2-MIB production within the 1-10 m layer of the water column. The highest 2-MIB concentration, 92.5 ng/L, was recorded in the riverine region, which was 2.54 and 14.52 times higher than that in the transitional and central parts of the reservoir, respectively. Temperature indirectly impacted algal growth and odorant production by modulating TN/TP ratios. Geosmin concentration responded rapidly to relatively low TN/TP ratios (< 25). Our findings suggest that phosphorus control in estuaries should be enhanced during thermal stratification period. In summary, our study provides valuable insights to inform pragmatic water intake strategies and the distribution and release of odorants caused by thermal stratification. This is particularly relevant in the context of future global warming and extremely high temperatures during the warm season., Competing Interests: Declaration of Competing Interest All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Glaucoma is a kind of neurodegenerative disorder characterized by irreversible loss of retinal ganglion cells (RGCs) and permanent visual impairment. It is reported that resveratrol (RES) is a promising drug for neurodegenerative diseases. However, the detailed molecular mechanisms underlying its protective potential have not yet been fully elucidated. The present study sought to investigate whether resveratrol could protect RGCs and retinal function triggered by acute ocular hypertension injury through the SIRT1/NF-κB pathway. An experimental glaucoma model was generated in C57BL/6J mice. Resveratrol was intraperitoneally injected for 5 days. Sirtinol was injected intravitreally on the day of retinal AOH injury. RGC survival was determined using immunostaining. TUNEL staining was conducted to evaluate retinal cell apoptosis. ERG was used to evaluate visual function. The proteins Brn3a, SIRT1, NF-κB, IL-6, Bax, Bcl2, and Cleaved Caspase3 were determined using western blot. The expression and localisation of SIRT1 and NF-κB in the retina were detected by immunofluorescence. Our data indicated that resveratrol treatment significantly increased Brn3a-labelled RGCs and reduced RGC apoptosis caused by AOH injury. Resveratrol administration also remarkably decreased NF-κB, IL-6, Bax, and Cleaved Caspase3 proteins and increased SIRT1 and Bcl2 proteins. Furthermore, resveratrol treatment obviously inhibited the reduction in ERG caused by AOH injury. Importantly, simultaneous administration of resveratrol and sirtinol abrogated the protective effect of resveratrol, decreased NF-κB protein expression, and increased SIRT1 protein levels. These results suggest that resveratrol administration significantly mitigates retinal AOH-induced RGCs loss and retinal dysfunction, and that this neuroprotective effect is partially regulated through the SIRT1/NF-κB pathway., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In the last few years, the presence of geosmin (GEO) in water bodies has caused serious problems related to water consumption by the population. Many studies focus on its occurrence and detection, but little is discussed about the technologies for treatment and removal of this contaminant. In this way, the present work aims to present a bibliographic search and a bibliometric analysis carried out in the Web of Science database and in VOSviewer software about geosmin remediation, in the last 10 years. 100 articles were found, of which only one, from 2021, was a review. It was possible to assess that the subject has gained greater notoriety in the last 7 years, since the year 2016 marked the increase of publications on the subject, as well as an increasing number of citations. Among the most published countries is the People's Republic of China, with 53% of publications. Bibliometric analysis showed that GEO is directly related to 2-methylisoborneol (2-MIB), since both occur simultaneously in water bodies. In addition, it was possible to identify that adsorptive processes are the most used in the removal of these contaminants, followed by advanced oxidative processes and biological processes, in that order.

Objective: To establishe an analysis and identification method for 2-methylisoborneol(2-MIB) and geosmin(GSM) in water using purge and trap-gas chromatography-mass spectrometry., Methods: The samples were enriched and analyzed using a purge and trap system, followed by the separation on a DB-624(30 m×0.25 mm, 1.4 μm) chromatographic column. Quantification was performed using gas chromatography-mass spectrometry with the selected ion monitoring and internal standard calibration., Results: The calibration curves for 2-MIB and GSM showed an excellent linearity in the range of 1 to 100 ng/L with R~2 values greater than 0.999. The detection limit and quantification limit for both 2-MIB and GSM were 0.33 ng/L and 1.0 ng/L, respectively. Spike recovery experiments were further carried on the source water and drinking water at three concentration levels. It showed that the average recoveries were from 82.0% to 111.0% for 2-MIB while 84.0% to 110% for GSM. Additionally, the test precision of 2-MIB and GSM ranged from 1.9% to 7.3% and 1.9% to 5.0%(n=6), respectively. The analysis of multiple samples including the local source water, treated water and distribution network water confirmed the existence of 2-MIB and GSM., Conclusion: Compared to the national standard(GB/T 5750.8-2023), the proposed method enables fully automated sample introduction and analysis without the extra pre-treatment. It provides the advantages of simplicity, good repeatability and high accuracy.

Although topical glucocorticoids (GCs) show potent anti-inflammatory activity in inflamed skin, they can also exert numerous harmful effects on epidermal structure and function. In contrast, topical applications of ligands of peroxisome proliferator-activated receptor-α (PPARα) not only reduce inflammation but also improve cutaneous barrier homeostasis. Therefore, we examined whether sequential topical GCs followed by topical Wy14643 (a ligand of PPARα) might be more effective than either alone for atopic dermatitis (AD) in a hapten (oxazolone (Ox))-induced murine model with multiple features of AD (Ox-AD). Despite expected anti-inflammatory benefits, topical GC alone induced (i) epidermal thinning; (ii) reduced expression of involucrin, loricrin, and filaggrin; and (iii) allowed outside-to-inside penetration of an epicutaneous tracer. Although Wy14643 alone yielded significant therapeutic benefits in mice with mild or moderate Ox-AD, it was less effective in severe Ox-AD. Yet, topical application of Wy14643 after GC was not only significantly effective comparable with GC alone, but it also prevented GC-induced structural and functional abnormalities in permeability barrier homeostasis. Moreover, rebound flares were largely absent after sequential treatment with GC and Wy14643. Together, these results show that GC and PPARα ligand therapy together is not only effective but also prevents development of GC-induced side effects, including rebound flares, in murine AD.

N-acyliminium reagents formed in situ from benzothiazole and alkyl chloroformates react with hydroxyarenes in a Friedel-Crafts manner, providing access to 2-(hydroxyaryl)-benzothiazolines with antibacterial properties. [ABSTRACT FROM AUTHOR]

Biocomposites comprising acidified chitosan (CTS) encapsulated in partially cross-linked natural rubber (NR) matrices (CTS-e-NR) were prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FE-SEM). The results of FT-IR, TGA and FE-SEM revealed that CTS was merely encapsulated within partially cross-linked natural rubber, and no chemical interaction was observed between CTS and NR. Soil burial biodegradation studies indicated that CTS-e-NR was degraded beyond any doubt, and weight loss of 48.98% was observed within 8 months. The release behaviour of CTS-e-NR was investigated in distilled water, where the naphthols (pesticide precursors) 1-hydroxynaphthalene (1-N), 2-hydroxynaphthalene (2-N), 1,4-dihydroxynaphthalene (1,4-N) and 2,6-dihydroxynaphthalene (2,6-N) were used as model pesticides. The percentage released in the first 24 h was found to be 7.38, 4.39, 2.96 and 6.95%, while 62.69, 60.64, 22.68 and 40.985% was released at the 35th day, for 1-N, 2-N, 1,4-N and 2,6-N, respectively. The release of naphthols followed non-Fickian diffusion: the combination of both polymer erosion and diffusion release mechanisms. In addition, the release behaviour was found to be consistently controlled and prolonged over a period of 35 days. Therefore, CTS-e-NR is strongly recommended for the controlled-release application of real pesticides. [ABSTRACT FROM AUTHOR]