A sustainable approach towards extraction of diosgenin from fenugreek seeds using polystyrene/divinyl benzene resin.

Diosgenin, a bioactive molecule; is one of the deeply explored saponin with a wide spectrum of benefits against various ailments. The extraction and yield enhancement of diosgenin from a wide range of naturally occurring medicinal products has always been a challenging task for its commercial usage. The current research work envisages the use of a novel resin to maximize the yield of diosgenin. The extracted diosgenin was characterized using modern techniques. The current method qualifies for the extraction of diosgenin at a large scale making it a commercially viable technique.

Discovery of ß-nitrostyrene derivatives as potential quorum sensing inhibitors for biofilm inhibition and antivirulence factor therapeutics against Serratia marcescens.

Quorum sensing (QS) inhibition has emerged as a promising target for directed drug design, providing an appealing strategy for developing antimicrobials, particularly against infections caused by drug-resistant pathogens. In this study, we designed and synthesized a total of 33 ß-nitrostyrene derivatives using 1-nitro-2-phenylethane (NPe) as the lead compound, to target the facultative anaerobic bacterial pathogen Serratia marcescens. The QS-inhibitory effects of these compounds were evaluated using S. marcescens NJ01 and the reporter strain Chromobacterium violaceum CV026. Among the 33 new ß-nitrostyrene derivatives, (E)-1-methyl-4-(2-nitrovinyl)benzene (m-NPe, compound 28) was proven to be a potent inhibitor that reduced biofilm formation of S. marcescens NJ01 by 79%. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) results revealed that treatment with m-NPe (50 µg/ml) not only enhanced the susceptibility of the formed biofilms but also disrupted the architecture of biofilms by 84%. m-NPe (50 µg/ml) decreased virulence factors in S. marcescens NJ01, reducing the activity of protease, prodigiosin, and extracellular polysaccharide (EPS) by 36%, 72%, and 52%, respectively. In S. marcescens 4547, the activities of hemolysin and EPS were reduced by 28% and 40%, respectively, outperforming the positive control, vanillic acid (VAN). The study also found that the expression levels of QS- and biofilm-related genes (flhD, fimA, fimC, sodB, bsmB, pigA, pigC, and shlA) were downregulated by 1.21- to 2.32-fold. Molecular dynamics analysis showed that m-NPe could bind stably to SmaR, RhlI, RhlR, LasR, and CviR proteins in a 0.1 M sodium chloride solution. Importantly, a microscale thermophoresis (MST) test revealed that SmaR could be a target protein for the screening of a quorum sensing inhibitor (QSI) against S. marcescens. Overall, this study highlights the efficacy of m-NPe in suppressing the virulence factors of S. marcescens, identifying it as a new potential QSI and antibiofilm agent capable of restoring or improving antimicrobial drug sensitivity.

Solvent-induced modulation of sensitivity and selectivity in the self-assembly of tetracationic cyclophanes with cholesterol sulphate, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate: Observations of significant shifts.

Cyclophane CP-1 demonstrates markedly distinct sensitivities toward Cholesterol sulfate (CH-S), Sodium Dodecyl Sulfate (SDS), and Sodium Dodecyl Benzene Sulfonate (SDBS) when the solvent is shifted minimally from a 95 % to a 98 % HEPES-DMSO mixture. In a 98:2 HEPES-DMSO mixture, CP-1 engages in highly selective self-assembly with CH-S, which is characterized by aggregation-induced emission enhancement (AIEE) in contrast to other steroidal sulfates such as pregnenolone sulfate (PRG-S), dehydroisoandrosterone sulfate (DIAND-S), taurocholic acid (TACH-S), and the surfactants SDS and SDBS. This assembly results in an approximate 40-fold increase in fluorescence intensity with three equivalents of CH-S and allows for the detection of concentrations as low as 200 nM under physiological conditions. Dynamic light scattering (DLS) studies illustrate the aggregation of CP-1 and CH-S, with the zeta potential of each shifting from negative values to nearly zero in a 1:2 CP-1:CH-S mixture, indicating self-assembly. This aggregation behavior is reversible, as demonstrated by a corresponding decrease and then increase in fluorescence intensity with temperature variations from 25 °C to 70 °C and back to 25 °C. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses show that CP-1 forms aggregates ranging from 100 to 180 nm, which increase to 150-250 nm upon interaction with CH-S. In a 95:5 HEPES-DMSO mixture, CP-1 exhibits a stronger AIEE response with SDS and SDBS compared to CH-S. Cyclophane CP-2, when dissolved in binary DMSO-water mixtures with water content exceeding 80 %, shows similar AIEE phenomena and undergoes selective fluorescence quenching with SDS and only a 50 % increase in fluorescence intensity with CH-S, irrespective of the HEPES concentration (95 % or 98 %).

LncRNA TUG1 regulates mir-34a-5p / SIRT6 to participate in benzene-induced hematotoxicity through PI3K / AKT /mTOR signaling pathway.

LncRNA TUG1 plays pivotal roles in various diseases. However, its exact roles in benzene - induced hematotoxicity remain unclear. Herein, we aimed to investigate the role and mechanism of TUG1 in hematoxic injuries caused by benzene. In the current study, TUG1 was found dramatically decreased in WBCs of benzene exposure workers and negatively correlated with benzene exposure duration and urine SPMA. In vitro assays demonstrated that TUG1 overexpression attenuated 1,4-BQ-caused suppression of cell viability and proliferation, and promotion of ROS generation and apoptosis via PI3K/AKT/mTOR pathway. Bioinformatic prediction and molecular assay validated miR-34a-5p was negatively regulated by TUG1. The miR-34a-5p was upregulated in 1,4-BQ treated cells and downregulated in TUG1 overexpression cells. Moreover, miR-34a-5p upregulation partially reversed the protective effects of TUG1 overexpression on 1,4-BQ - caused cytotoxicity. Furthermore, SIRT6 was a downstream target gene of miR-34a-5p, whose expression was reduced in miR-34a-5p upregulation cells and elevated in TUG1 overexpression cells. Upregulated SIRT6 could counteract accelerated cytotoxicity mediated by miR-34a-5p upregulation after 1,4-BQ treatment. Taken together, our study revealed that the critical role of the TUG1/miR-34a-5p/SIRT6 axis in benzene-caused hematotoxicity, and provided scientific basis for further understanding the epigenetic regulatory mechanisms underlying benzene hematotoxicity.

Soil benzene emissions and inhalation health risks affected by various land covers.

Accurate quantification of soil volatile organic compounds (VOCs) flux is crucial for assessing inhalation environmental health risks and developing region-specific remediation strategies. However, land cover significantly influences VOCs emissions from soil. This study investigated benzene, a representative VOCs, using a laboratory flux chamber and numerical simulations to evaluate its release patterns under different surface covers, including bare soil (no cover), clay brick, cement, and grass. In the experiment, gaseous benzene was collected using an adsorption tube filled with Tenax-TA adsorbent. The collected samples were subsequently analyzed using thermal desorption coupled with gas chromatography-mass spectrometry. By integrating these findings with environmental health risk assessment methodologies, we developed a tailored approach for assessing inhalation health risks at benzene-contaminated sites with varying land covers. Additionally, we conducted application studies of this method across various scenarios. The results indicate that soil benzene emissions could be reduced by using low-permeability coverings such as clay brick and cement, as well as by planting vegetation. The average fluxes of benzene through covering materials were of the order of 1.22×10-2, 4.37×10-3, 2.47×10-3, and 9.88×10-4 mg·m-2·s-1 for bare soil, clay brick, grass, and cement, respectively. The application of clay brick and cement coverings on the soil surface results in more pollutants remaining in the soil in liquid and adsorbed states, making them less likely to volatilize. The inhalation carcinogenic risk (CR) values for soil benzene at an abandoned oil refinery site in Northwestern China under bare soil, brick, and cement cover are 1.3×10-6, 1.22×10-6, and 9.73×10-7, respectively. Low-permeability covers such as clay brick and cement reduces the inhalation CR of gaseous benzene from the surface soil, and delays the growth trend of cumulative inhalation CR.

Crystal structure and Hirshfeld surface analysis of (E)-N-(2-styrylphen-yl)benzene-sulfonamide.

The crystal structure of the title compound C20H17NO2S features hydrogen-bonding and C-H⋯π inter-actions. Hirshfeld surface analysis revealed that H⋯H, C⋯H/H⋯C and O⋯H/H⋯O inter-actions make a major contribution to the crystal packing. Docking studies were carried out to determine the binding affinity and inter-action profile of the title compound with EGFR kinase, a member of the ErbB family of receptor tyrosine kinases, which is crucial for processes such as cell proliferation and differentiation. The title compound shows a strong binding affinity with EGFR kinase, with the most favourable conformation having a binding energy of -8.27 kcal mol-1 and a predicted IC50 of 870.34 nM, indicating its potential as a promising candidate for targeted lung cancer therapy.

Visible-Light-Driven Oxidation of Benzene to Phenol with O2 over Photoinduced Oxygen-Vacancy-Rich WO3.

Direct photocatalytic conversion of benzene to phenol with O2 is a green alternative to the traditional synthesis. The key is to find an effective photocatalyst to do the trick. Defect engineering of semiconductors with oxygen vacancies (OVs) is an emerging strategy for catalyst fabrication. OVs can trap electrons to promote charge separation and serving as adsorption sites for O2 activation. However, randomly distribution of OVs on the semiconductor surface often results in mismatching the charge carrier dynamics under irradiation, thus failing to fulfill the unique advantages of OVs for photoredox functions. Herein, we demonstrate that abundant OVs can be facilely generated and precisely located adjacent to the reductive sites on reducible oxide semiconductors such as tungsten oxide (WO3) via a simple photochemistry strategy. Such photoinduced OVs are well suited for photocatalytic benzene oxidation with O2 as they readily capture photogenerated electrons from the reductive sites of WO3 to activate adsorbed O2. 18O-labeling experiments further confirm that the OVs also facilitate the integration of oxygen atoms from O2 into phenol, revealing in detail the pathway for photocatalytic benzene hydroxylation. This study demonstrates that the photochemistry approach is an appealing strategy for the synthesis of high-performance OVs-rich photocatalysts for solar-induced chemical conversion.

Theoretical and experimental investigation of mixed-ligand metal(II) Schiff base complexes using maleic acid as the auxiliary ligand.

This work is focused on the synthesis of several transition metal complexes [ML(MA)], where M = Copper (II), Zinc (II), Cobalt (II) and Nickel (II), MA = maleic acid and L = Schiff base generated from benzene-1,2-diamine [o-phenylenediamine] and 4-chlorobenzaldehyde. The characterization using Fourier-Transform Infrared, Nuclear Magnetic Resonance spectroscopy, Ultraviolet-Visible spectra, Mass, Electro Paramagnetic Resonance and elemental analysis confirm the square planar geometry of the complexes. The in vitro antimicrobial potential of the complexes has been tested by the broth dilution method and the antioxidant method has been done by free radical scavenging analysis. The in vitro methods reveal the outstanding biological characteristics of the copper complexes. The molecular structure of the ligand and its metal (II) complexes has been optimized using Density Functional Theory studies performed by the Gaussian-09 software and their parameters have been discussed. Natural Bond Orbital and Frontier Molecular Orbital analyses have assessed the presence of a metal-ligand bond in complexes. In addition, molecular docking studies have also been performed on antiviral activity of all the complexes using a viral protein and their interacting amino acids.

All the metal complexes have the strong tendency to undergo intercalation mode of binding with CT DNA.The optimized geometry and the quantum mechanical examinations are carried out using Gaussian 09W software.The docking of synthesized compounds with SARS-CoV-2 receptor 7ACS protease 7AEH represents the docking of metal complexes.In silico and in vitro analyses of the synthesized compounds.

Data-driven machine learning models for predicting the maximum absorption and emission wavelengths of single benzene fluorophores.

Single benzene fluorophores (SBFs) have garnered significant research attention due to their ease of preparation, seamless diffusion into biological samples, and low molecular weight. Accurately predicting the molecular photophysical properties, specifically the maximum absorption and emission wavelengths, is pivotal in advancing functional SBFs. In this study, we introduce a machine-learning model to estimate the maximum absorption and emission wavelengths of SBFs precisely. This model leverages a Full Connect Neural Network and computational chemistry and is tailored to address the challenges associated with a relatively small dataset (81 SBFs). Remarkably, our model (SBFs-ML) demonstrates impressive accuracy, yielding a mean relative error of 1.54 % and 2.93 % for SBFs' maximum absorption and emission wavelengths, respectively. Importantly, the SBFs-ML was bullied based on only three descriptors, resulting in strong interpretability. Experimental results have strongly corroborated these predictions. Our prediction methods are poised to facilitate significantly the efficient design and creation of SBFs.

A Fluorescence-Based Assay for Measuring Polyamine Biosynthesis Aminopropyl Transferase-Mediated Catalysis.

Polyamines are polycationic molecules that are crucial in a wide array of cellular functions. Their biosynthesis is mediated by aminopropyl transferases (APTs), which are promising targets for antimicrobial, antineoplastic and antineurodegenerative therapies. A major limitation in studying APT enzymes, however, is the lack of high-throughput assays to measure their activity. We have developed the first fluorescence-based assay, DAB-APT, for the measurement of APT activity using 1,2-diacetyl benzene (DAB), which forms fluorescent conjugates with putrescine, spermidine, and spermine, with fluorescence intensity increasing with the carbon chain length. The assay has been validated using APT enzymes from Saccharomyces cerevisiae and Plasmodium falciparum, and the data further validated by mass spectrometry and thin-layer chromatography. Using mass spectrometry analysis, the structures of the fluorescent putrescine, spermidine and spermine 1,2-DAB adducts were determined to be substituted 1,3-dimethyl isoindoles. The DAB-APT assay is optimized for high-throughput screening, facilitating the evaluation of large chemical libraries. Given the critical roles of APTs in infectious diseases, oncology, and neurobiology, the DAB-APT assay offers a powerful tool with broad applicability, poised to drive advancements in research and drug discovery.

Confined Cu Single Sites in ZSM-5 for Photocatalytic Hydroxylation of Benzene to Phenol.

Zeolites with band-like charge transport properties have exhibited their potential activities in sensing, optics, and electronics. Herein, a precisely designed Cu@ZSM-5 catalyst is presented with an ultra-wide bandgap of 4.27 eV, showing excellent photocatalytic activity in hydroxylation of benzene with benzene conversion 27.9% and phenol selectivity 97.6%. The SXRD and Rietveld refinement results illustrate that Cu@ZSM-5 has an average of 0.8 Cu atoms per unit cell and the single Cu atoms located in the cross-section of the sinusoidal and straight channels. XANES and EXAFS further demonstrate that the Cu atoms have an oxidation state of +2, coordinated with three OMFI-framework atoms and one ─OH group. Detailed characterizations demonstrate that the Cu@ZSM-5 with tailored bandgap is able to enhance the photoinduced electron-hole separation and hence promote selective hydroxylation of benzene to phenol via the superoxide radical route. This work may open a new way for designing electrically conductive zeolite-supported photocatalysts.

Data-driven approaches to study the spectral properties of chemical structures.

The molecular energy, which is the sum of all eigenvalues, is crucial in determining the total π-electron energy of conjugated hydrocarbon molecules. We used machine learning techniques to calculate the energy, inertia, nullity, signature, and Estrada index of molecular graphs for bismuth tri-iodide and benzene rings embedded in P-type surfaces within 2D networks. We applied MATLAB to extract the actual eigenvalues from the data and developed general equations for these molecular properties. We then used these equations to estimate the values and compared them to the actual values through graphical analysis. Our results demonstrate the potential of data-driven techniques in predicting molecular properties and enhancing our understanding of spectral theory.

LaCoO3 is a promising catalyst for the dry reforming of benzene used as a surrogate of biomass tar.

Tar build-up is one of the bottlenecks of biomass gasification processes. Dry reforming of tar is an alternative solution if the oxygen chemical potential on the catalyst surface is at a sufficient level. For this purpose, an oxygen-donor perovskite, LaCoO3, was used as a catalyst for the dry reforming of tar. To circumvent the complexity of the tar and its constituents, the benzene molecule was chosen as a model compound. Dry reforming of benzene vapor on the LaCoO3 catalyst was investigated at temperatures of 600, 700, and 800 °C; at CO2/C6H6 ratios of 3, 6, and 12; and at space velocities of 14,000 and 28,000 h-1. The conventional Ni(15 wt.%)/Al2O3 catalyst was also used as a reference material to determine the relative activity of the LaCoO3 catalyst. Different characterization techniques such as X-ray diffraction, N2 adsorption-desorption, temperature-programmed reduction, and oxidation were used to determine the physicochemical characteristics of the catalysts. The findings demonstrated that the LaCoO3 catalyst has higher CO2 conversion, higher H2 and CO yields, and better stability than the Ni(15 wt.%)/γ-Al2O3 catalyst. The improvement in activity was attributed to the strong capacity of LaCoO3 for oxygen exchange. The transfer of lattice oxygen from the surface of the LaCoO3 catalyst facilitates the oxidation of carbon and other surface species and leads to higher conversion and yields.

Anaerobic benzene oxidation in Geotalea daltonii involves activation by methylation and is regulated by the transition state regulator AbrB.

Benzene is a widespread groundwater contaminant that persists under anoxic conditions. The aim of this study was to more accurately investigate anaerobic microbial degradation pathways to predict benzene fate and transport. Preliminary genomic analysis of Geotalea daltonii strain FRC-32, isolated from contaminated groundwater, revealed the presence of putative aromatic-degrading genes. G. daltonii was subsequently shown to conserve energy for growth on benzene as the sole electron donor and fumarate or nitrate as the electron acceptor. The hbs gene, encoding for 3-hydroxybenzylsuccinate synthase (Hbs), a homolog of the radical-forming, toluene-activating benzylsuccinate synthase (Bss), was upregulated during benzene oxidation in G. daltonii, while the bss gene was upregulated during toluene oxidation. Addition of benzene to the G. daltonii whole-cell lysate resulted in toluene formation, indicating that methylation of benzene was occurring. Complementation of σ54- (deficient) E. coli transformed with the bss operon restored its ability to grow in the presence of toluene, revealing bss to be regulated by σ54. Binding sites for σ70 and the transition state regulator AbrB were identified in the promoter region of the σ54-encoding gene rpoN, and binding was confirmed. Induced expression of abrB during benzene and toluene degradation caused G. daltonii cultures to transition to the death phase. Our results suggested that G. daltonii can anaerobically oxidize benzene by methylation, which is regulated by σ54 and AbrB. Our findings further indicated that the benzene, toluene, and benzoate degradation pathways converge into a single metabolic pathway, representing a uniquely efficient approach to anaerobic aromatic degradation in G. daltonii. IMPORTANCE: The contamination of anaerobic subsurface environments including groundwater with toxic aromatic hydrocarbons, specifically benzene, toluene, ethylbenzene, and xylene, has become a global issue. Subsurface groundwater is largely anoxic, and further study is needed to understand the natural attenuation of these compounds. This study elucidated a metabolic pathway utilized by the bacterium Geotalea daltonii capable of anaerobically degrading the recalcitrant molecule benzene using a unique activation mechanism involving methylation. The identification of aromatic-degrading genes and AbrB as a regulator of the anaerobic benzene and toluene degradation pathways provides insights into the mechanisms employed by G. daltonii to modulate metabolic pathways as necessary to thrive in anoxic contaminated groundwater. Our findings contribute to the understanding of novel anaerobic benzene degradation pathways that could potentially be harnessed to develop improved strategies for bioremediation of groundwater contaminants.

Amino-Terephthalonitrile and Amino-Terephthalate-Based Single Benzene Fluorophores - Compact Color Tunable Molecular Dyes for Bioimaging and Bioanalysis.

This review article discusses the emerging amino-terephthalonitrile (Am-TN) and amino terephthalate-based single benzene fluorophores (SBFs) for their highly emissive nature and potential for numerous technical applications. Am-TN-SBFs are a new class of SBFs having amine as the electron donating (EDG) and dinitrile as the electron withdrawing group (EWG). The beauty of these Am-TN-SBFs lies in excellent intramolecular charge transfer between the EDG and EWG. The placement of two nitrile groups in para-position on the benzene ring allows better charge transfer from the donating amines to the linear nitrile group leading to the strongly emissive nature. We also outline here the latest developments in the well-known family of amino terephthalate SBFs reported in the last 2 to 3 years. Amino terephthalate SBFs have esters as the EWG and amine as the EDG. These have intramolecular H-bonding between the EDG and EWG which is responsible for their emissive behavior.

Occupational benzene exposure and risk of head and neck cancer: A systematic review and meta-analysis.

INTRODUCTION: Benzene, an aromatic hydrocarbon, is a well-known leukemogen. To date, the link between benzene exposure and solid cancers is under examination. Our objective is to perform a systematic review and meta-analysis to evaluate if the occupational exposure to benzene is associated with the incidence and mortality of head and neck cancers (HNCs). METHODS: We systematically reviewed the literature for pertinent cohort studies mentioned in the most recent IARC Monograph on benzene working exposure and other cohorts and case-controls identified via a literature search performed in PubMed, Scopus, and Embase, from their inception to March 2024. Stratified multilevel meta-analyses according to study design, cancer type, industrial sector, quality score of the articles, geographic region and risk of exposure bias were conducted. RESULTS: A total of 29 independent studies were included in our review and multilevel meta-analysis. The findings revealed a bordeline association between exposure to occupational benzene and incidence of HNCs RR = 1.27, 95% CI = 1.00-1.64, I2 level2 = 0%, I2level3 = 43.30%, P < 0.05). In addition, we found a significant increased overall risk of HNCs in females (RR = 1.68, 95% CI = 1.07-2.61; I2level2 = 0%, I2level3 = 0%, P = 0.433). Stratification analysis according to cancer sites showed a significant increase in risk of nose & sinuses cancers (RR = 3.72, 95% CI = 2.07-6.68; I2level2 = 34.13%, I2level3 = 0%, P = 0.17). European cohorts (RR = 1.31, 95% CI = 1.08-1.59, p < 0.01) and lower quality studies (RR = 1.39, 95% CI = 1.00-1.91; I2level2 = 0%, I2level3 = 45.94%, P < 0.001). No evidence of publication bias was found (Egger test P = 0.103). CONCLUSIONS: In conclusion, this systematic review and meta-analysis provide evidence that workers with occupational exposure to benzene might be at increased risk of HNCs, in particular for nose & sinuses cancer. However, it is essential to consider the limitations of the studies, particularly residual confounding, and the areas that need further study to improve our understanding of the subject.

Carcinogenic industrial air pollution and postmenopausal breast cancer risk in the National Institutes of Health AARP Diet and Health Study.

BACKGROUND: Chemicals emitted from industrial facilities include known or suspected mammary carcinogens and endocrine disruptors, but epidemiologic studies are limited. We evaluated associations between air emissions of multiple carcinogenic chemicals and postmenopausal breast cancer risk in a large prospective U.S. METHODS: We used the U.S. Environmental Protection Agency's Toxics Release Inventory to estimate historical airborne emissions (1987-1995) of 19 known and probable carcinogens for participants enrolled (1995-1996) in the NIH-AARP Diet and Health Study. Among 170,402 women, 15,124 breast cancers were diagnosed through 2018. We constructed inverse distance- and wind-weighted average emissions metrics within 1, 2, 5, and 10 km of the enrollment address for each chemical. We estimated multivariable adjusted HRs and 95 % CIs for categories (quartiles, tertiles, medians) of each chemical in association with breast cancer overall and separately by type (invasive, ductal carcinoma in situ) and estrogen receptor (ER) status. RESULTS: We observed an association between benzene emissions and breast cancer risk that was strongest at 1 km (HRQ4 vs. non-exposed = 2.06, 95 %CI: 1.34-3.17; p-trend = 0.001). The magnitude of the association weakened with increasing distance (2 km HRQ4 vs. non-exposed = 1.17, 95 %CI=0.92-1.49; p-trend = 0.19; 5 km HRQ4 vs. non-exposed = 1.05, 95 %CI=0.94-1.16; p-trend = 0.37; 10 km HRQ4 vs. non-exposed = 0.95, 95 %CI=0.89-1.02; p-trend = 0.19) and appeared to be most relevant for invasive rather than intraductal disease. Overall risk was also elevated for vinyl chloride at 5 km (HR≥median vs. non-exposed = 1.20, 95 %CI=1.01-1.43; p-trend = 0.04), but not 2 km or 10 km. We observed suggestive associations for asbestos, trichloroethylene, and styrene in different subgroup analyses, but risk patterns were not clear across distances. Associations with other chemicals were generally null, with limited evidence of heterogeneity by disease type or ER status. CONCLUSIONS: An increased risk of breast cancer associated with relatively high levels of industrial benzene emissions warrants additional study, particularly among participants with diverse sociodemographic characteristics that live in areas with higher density of industrial facilities.

Metagenomic and genomic sequences from a nitrate-reducing benzene-degrading enrichment culture.

Metagenome-assembled genomes (MAGs) were recovered from metagenomic assemblies from a nitrate-reducing benzene-degrading enrichment culture. Ten MAGs of high quality or functional interest to benzene degradation are reported, seven of which are single contig genomes.

Benzene metabolism and health risk evaluation: insights gained from biomonitoring.

Metabolic conversion of benzene (Bz) is thought to be required for the hematotoxic effects observed following Bz exposures. Most safe exposure limits set for Bz utilize epidemiology data on the hematotoxic effects of Bz for the dose-response assessments. These hematotoxic effects occurred among workers exposed to elevated Bz levels, thus dose extrapolation is required for assessing relevant risks for populations exposed orders of magnitude lower. Thus, understanding how Bz is metabolized over a wide range of air Bz levels is an important topic for risk assessments for Bz. Here, we analyze biomonitoring data for workers exposed to Bz to make evaluations of how the metabolism of Bz varies across a wide range of exposures. Our analysis indicates that the presence of metabolites derived from exposures to sources other than Bz (nonspecific metabolites of Bz) are significant confounders among biomonitoring studies and this precludes making any assessments of how Bz metabolism differs below approximately 3 ppm air Bz exposures using such nonspecific metabolites.

Occupational exposure to benzene and risk of non-Hodgkin lymphoma in an extended follow-up of two population-based prospective cohorts of Chinese men and women.

The carcinogenicity of benzene was reevaluated by the International Agency for Research on Cancer in 2017, with the Working Group reaffirming positive yet inconclusive associations with non-Hodgkin lymphoma (NHL). To extend our previous observation of a significant exposure-response for cumulative occupational benzene exposure and NHL risk among Chinese women in a population-based cohort in Shanghai, we extended follow-up of this cohort and pooled the data with a similarly designed population-based cohort of men in Shanghai. Cumulative exposure estimates were derived for 134,449 participants in the pooled analysis by combining ordinal job-exposure matrix intensity ratings with quantitative benzene measurements from an inspection database of Shanghai factories. Associations between benzene exposure metrics and NHL (n = 363 cases including multiple myeloma [MM]) were assessed using Cox proportional hazard models. Ever occupational exposure to benzene in the pooled population was associated with NHL risk (HR = 1.5, 95% CI = 1.2-2.0), and exposure-response relationships were observed for increasing duration (ptrend = .003) and cumulative exposure (ptrend = .003). Associations with ever exposure, duration, and cumulative exposure were similar for NHL with and without MM in the case definition, including lifetime cumulative exposures in the highest quartile (HR = 1.6, 95% CI = 1.1-2.4 with MM included; HR = 1.7, 95% CI = 1.1-2.7 with MM excluded). An elevated risk of the chronic lymphocytic leukemia subtype was suggested in the pooled analyses (HR for ever vs. never exposure = 2.3, 95% CI = 0.9-5.6). These observations provide additional support for a plausible association between occupational benzene exposure and risk of NHL.