RESUMEN

The adsorption of pollutants can not only promote the direct surface reaction, but also modify the catalyst itself to improve its photoelectric characteristics, which is rarely studied for water treatment with inorganic photocatalyst. A highly crystalline BiOBr (c-BiOBr) was synthesized by a two-step preparation process. Owing to the calcination, the highly crystalline enhanced the interface interaction between pollutant and c-BiOBr. The complex of organic pollutant and [Bi2O2]2+ could promote the active electron transfer from the adsorbed pollutant to c-BiOBr for the direct pollutant degradation by holes (h+). Moreover, the pollutant adsorption actually modified c-BiOBr and promoted more unpaired electrons, which would coupling with the photoexcitation to promote generate more O2•-. The molecular modification effect derived from pollutant adsorption significantly improved the removal of pollutants. This work strongly deepens the understanding of the molecular modification effect from the pollutant adsorption and develops a novel and efficient approach for water treatment.

Asunto(s)

Contaminantes Químicos del Agua , Adsorción , Contaminantes Químicos del Agua/química , Catálisis , Bismuto/química , Purificación del Agua/métodos

RESUMEN

Heterogeneous oxidation by gas-phase oxidants is an important chemical transformation pathway of secondary organic aerosol (SOA) and plays an important role in controlling the abundance, properties, as well as climate and health impacts of aerosols. However, our knowledge on this heterogeneous chemistry remains inadequate. In this study, the heterogeneous oxidation of α-pinene ozonolysis SOA by hydroxyl (OH) radicals was investigated under both low and high relative humidity (RH) conditions, with an emphasis on the evolution of molecular composition of SOA and its RH dependence. It is found that the heterogeneous oxidation of SOA at an OH exposure level equivalent to 12 hr of atmospheric aging leads to particle mass loss of 60% at 25% RH and 95% at 90% RH. The heterogeneous oxidation strongly changes the molecular composition of SOA. The dimer-to-monomer signal ratios increase dramatically with rising OH exposure, in particular under high RH conditions, suggesting that aerosol water stimulates the reaction of monomers with OH radicals more than that of dimers. In addition, the typical SOA tracer compounds such as pinic acid, pinonic acid, hydroxy pinonic acid and dimer esters (e.g., C17H26O8 and C19H28O7) have lifetimes of several hours against heterogeneous OH oxidation under typical atmospheric conditions, which highlights the need for the consideration of their heterogeneous loss in the estimation of monoterpene SOA concentrations using tracer-based methods. Our study sheds lights on the heterogeneous oxidation chemistry of monoterpene SOA and would help to understand their evolution and impacts in the atmosphere.

Asunto(s)

Aerosoles , Contaminantes Atmosféricos , Monoterpenos Bicíclicos , Humedad , Radical Hidroxilo , Oxidación-Reducción , Aerosoles/química , Radical Hidroxilo/química , Monoterpenos Bicíclicos/química , Contaminantes Atmosféricos/química , Contaminantes Atmosféricos/análisis , Ozono/química , Modelos Químicos , Atmósfera/química , Monoterpenos/química

RESUMEN

Sewage sludge in cities of Yangzi River Belt, China, generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system, which caused low bioenergy recovery and carbon emission benefits in conventional anaerobic digestion (CAD). Therefore, this paper is on a pilot scale, a bio-thermophilic pretreatment anaerobic digestion (BTPAD) for low organic sludge (volatile solids (VS) of 4%) was operated with a long-term continuous flow of 200 days. The VS degradation rate and CH4 yield of BTPAD increased by 19.93% and 53.33%, respectively, compared to those of CAD. The analysis of organic compositions in sludge revealed that BTPAD mainly improved the hydrolysis of proteins in sludge. Further analysis of microbial community proportions by high-throughput sequencing revealed that the short-term bio-thermophilic pretreatment was enriched in Clostridiales, Coprothermobacter and Gelria, was capable of hydrolyzing acidified proteins, and provided more volatile fatty acid (VFA) for the subsequent reaction. Biome combined with fluorescence quantitative polymerase chain reaction (PCR) analysis showed that the number of bacteria with high methanogenic capacity in BTPAD was much higher than that in CAD during the medium temperature digestion stage, indicating that short-term bio-thermophilic pretreatment could provide better methanogenic conditions for BTPAD. Furthermore, the greenhouse gas emission footprint analysis showed that short-term bio-thermophilic pretreatment could reduce the carbon emission of sludge anaerobic digestion system by 19.18%.

Asunto(s)

Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas del Alcantarillado/microbiología , Anaerobiosis , Eliminación de Residuos Líquidos/métodos , Proyectos Piloto , Reactores Biológicos/microbiología , Metano/metabolismo , Metano/análisis , Carbono/metabolismo , Carbono/análisis , China , Biocombustibles

RESUMEN

Biomolecules contain various heterogeneities in their structures and local chemical properties, and their functions emerge through the dynamics encoded by these heterogeneities. Molecular dynamics model-based studies will greatly contribute to the elucidation of such chemical/mechanical structure-dynamics-function relationships and the mechanisms that generate them. Coarse-grained molecular dynamics models with appropriately designed nonuniform local interactions play an important role in considering the various phenomena caused by large molecular complexes consisting of various proteins and DNA such as nuclear chromosomes. Therefore, in this chapter, we will introduce a method for constructing a coarse-grained molecular dynamics model that simulates the global behavior of each chromosome in the nucleus of a mammalian cell containing many giant chromosomes.

Asunto(s)

Núcleo Celular , Simulación de Dinámica Molecular , Núcleo Celular/metabolismo , Núcleo Celular/química , Animales , Humanos , Cromosomas/química , ADN/química , ADN/metabolismo , Mamíferos

RESUMEN

Polymer modeling has been playing an increasingly important role in complementing 3D genome experiments, both to aid their interpretation and to reveal the underlying molecular mechanisms. This chapter illustrates an application of Hi-C metainference, a Bayesian approach to explore the 3D organization of a target genomic region by integrating experimental contact frequencies into a prior model of chromatin. The method reconstructs the conformational ensemble of the target locus by combining molecular dynamics simulation and Monte Carlo sampling from the posterior probability distribution given the data. Using prior chromatin models at both 1 kb and nucleosome resolution, we apply this approach to a 30 kb locus of mouse embryonic stem cells consisting of two well-defined domains linking several gene promoters together. Retaining the advantages of both physics-based and data-driven strategies, Hi-C metainference can provide an experimentally consistent representation of the system while at the same time retaining molecular details necessary to derive physical insights.

Asunto(s)

Teorema de Bayes , Cromatina , Simulación de Dinámica Molecular , Animales , Ratones , Cromatina/genética , Cromatina/química , Cromatina/metabolismo , Genoma , Genómica/métodos , Método de Montecarlo , Células Madre Embrionarias de Ratones/metabolismo

RESUMEN

Phenol and some of its derivatives exhibit interesting tunneling motions consisting of two groups of transitions separated by a few hundred MHz. Recently, one of its derivatives, 2,6-di-tert-butylphenol, has shown additional hyperfine tunneling components, the origin of which remains unclear. In this work, another member of the family, 2,6-diethylphenol, has been investigated through its rotational spectrum. The jet-cooled broadband chirped-pulse Fourier transform microwave spectra in the 2-8 GHz frequency region revealed the presence of two conformers. The comparison with the equilibrium structure obtained by computational calculations at the B3LYP-D3(BJ)/Def2-TZVP level validates the structural determination and the orientation of the lateral ethyl groups. Additional observation of all the singly-substituted 13C isotopologues for the most stable ones allowed the determination of the substitution structure by means of the Kraitchman equations. Both conformers exhibited tunneling that was reproduced using an advanced 1D model, which provides an estimate of the barrier height for both conformers.

RESUMEN

Lake Baiyangdian is one of China's largest macrophyte - derived lakes, facing severe challenges related to water quality maintenance and eutrophication prevention. Dissolved organic matter (DOM) was a huge carbon pool and its abundance, property, and transformation played important roles in the biogeochemical cycle and energy flow in lake ecosystems. In this study, Lake Baiyangdian was divided into four distinct areas: Unartificial Area (UA), Village Area (VA), Tourism Area (TA), and Breeding Area (BA). We examined the diversity of DOM properties and sources across these functional areas. Our findings reveal that DOM in this lake is predominantly composed of protein - like substances, as determined by excitation - emission matrix and parallel factor analysis (EEM - PARAFAC). Notably, the exogenous tyrosine-like component C1 showed a stronger presence in VA and BA compared to UA and TA. Ultrahigh - resolution mass spectrometry (FT - ICR MS) unveiled a similar DOM molecular composition pattern across different functional areas due to the high relative abundances of lignan compounds, suggesting that macrophytes significantly influence the material structure of DOM. DOM properties exhibited specific associations with water quality indicators in various functional areas, as indicated by the Mantel test. The connections between DOM properties and NO3N and NH3N were more pronounced in VA and BA than in UA and TA. Our results underscore the viability of using DOM as an indicator for more precise and scientific water quality management.

Asunto(s)

Monitoreo del Ambiente , Lagos , Lagos/química , China , Monitoreo del Ambiente/métodos , Eutrofización , Sustancias Húmicas/análisis , Calidad del Agua , Espectrometría de Masas/métodos , Contaminantes Químicos del Agua/análisis , Ecosistema

RESUMEN

Significance: Standardization of fluorescence molecular imaging (FMI) is critical for ensuring quality control in guiding surgical procedures. To accurately evaluate system performance, two metrics, the signal-to-noise ratio (SNR) and contrast, are widely employed. However, there is currently no consensus on how these metrics can be computed. Aim: We aim to examine the impact of SNR and contrast definitions on the performance assessment of FMI systems. Approach: We quantified the SNR and contrast of six near-infrared FMI systems by imaging a multi-parametric phantom. Based on approaches commonly used in the literature, we quantified seven SNRs and four contrast values considering different background regions and/or formulas. Then, we calculated benchmarking (BM) scores and respective rank values for each system. Results: We show that the performance assessment of an FMI system changes depending on the background locations and the applied quantification method. For a single system, the different metrics can vary up to ∼ 35 dB (SNR), ∼ 8.65 a . u . (contrast), and ∼ 0.67 a . u . (BM score). Conclusions: The definition of precise guidelines for FMI performance assessment is imperative to ensure successful clinical translation of the technology. Such guidelines can also enable quality control for the already clinically approved indocyanine green-based fluorescence image-guided surgery.

Asunto(s)

Benchmarking , Imagen Molecular , Imagen Óptica , Fantasmas de Imagen , Relación Señal-Ruido , Imagen Molecular/métodos , Imagen Molecular/normas , Imagen Óptica/métodos , Imagen Óptica/normas , Procesamiento de Imagen Asistido por Computador/métodos

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Thrombosis is a common cause of morbidity and mortality worldwide. Lagopsis supina (Stephan ex Willd.) Ikonn.-Gal. ex Knorring is an ancient Chinese herbal medicine used for treating thrombotic diseases. Nevertheless, the antithrombotic mechanisms and effective constituents of this plant have not been clarified. AIM OF THE STUDY: This work aimed to elucidate the pharmacodynamics and mechanism of L. supina against thrombosis. MATERIALS AND METHODS: Systematic network pharmacology was used to explore candidate effective constituents and hub targets of L. supina against thrombosis. Subsequently, the binding affinities of major constituents with core targets were verified by molecular docking analysis. Afterward, the therapeutic effect and mechanism were evaluated in an arteriovenous bypass thrombosis rat model. In addition, the serum metabolomics analysis was conducted using ultra-high performance liquid chromatography coupled with Q-Exactive mass spectrometry. RESULTS: A total of 124 intersected targets of L. supina against thrombosis were predicted. Among them, 24 hub targets were obtained and their mainly associated with inflammation, angiogenesis, and thrombosis approaches. Furthermore, 9 candidate effective constituents, including (22E,24R)-5α,8α-epidioxyergosta-6,22-dien-3ß-ol, aurantiamide, (22E,24R)-5α,8α-epidioxyergosta-6,9 (11),22-trien-3ß-ol, lagopsinA, lagopsin C, 15-epi-lagopsin C, lagopsin D, 15-epi-lagopsin D, and lagopsin G in L. supina and 6 potential core targets (TLR-4, TNF-α, HIF-1α, VEGF-A, VEGFR-2, and CLEC1B) were acquired. Then, these 9 constituents demonstrated strong binding affinities with the 6 targets, with their lowest binding energies were all less than -5.0 kcal/mol. The antithrombotic effect and potential mechanisms of L. supina were verified, showing a positively associated with the inhibition of inflammation (TNF-α, IL-1ß, IL-6, IL-8, and IL-10) and coagulation cascade (TT, APTT, PT, FIB, AT-III), promotion of angiogenesis (VEGF), suppression of platelet activation (TXB2, 6-keto-PGF1α, and TXB2/6-keto-PGF1α), and prevention of fibrinolysis (t-PA, u-PA, PAI-1, PAI-1/t-PA, PAI-1/u-PA, and PLG). Finally, 14 endogenous differential metabolites from serum samples of rats were intervened by L. supina based on untargeted metabolomics analysis, which were closely related to amino acid metabolism, inflammatory and angiogenic pathways. CONCLUSION: Our integrated strategy based on network pharmacology, molecular docking, metabolomics, and in vivo experiments revealed for the first time that L. supina exerts a significant antithrombotic effect through the inhibition of inflammation and coagulation cascade, promotion of angiogenesis, and suppression of platelet activation. This paper provides novel insight into the potential of L. supina as a candidate agent to treat thrombosis.

Asunto(s)

Fibrinolíticos , Metabolómica , Simulación del Acoplamiento Molecular , Farmacología en Red , Ratas Sprague-Dawley , Trombosis , Animales , Fibrinolíticos/farmacología , Fibrinolíticos/química , Fibrinolíticos/aislamiento & purificación , Ratas , Masculino , Trombosis/tratamiento farmacológico , Medicamentos Herbarios Chinos/farmacología , Medicamentos Herbarios Chinos/química

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Pogostemonis Herba has long been used in traditional Chinese medicine to treat inflammatory disorders. Patchouli essential oil (PEO) is the primary component of Pogostemonis Herba, and it has been suggested to offer curative potential when applied to treat ulcerative colitis (UC). However, the pharmacological mechanisms of PEO for treating UC remain to be clarified. AIM OF THE STUDY: To elucidate the pharmacological mechanisms of PEO for treating UC. METHODS AND RESULTS: In the present study, transcriptomic and network pharmacology approaches were combined to clarify the mechanisms of PEO for treating UC. Our results reveal that rectal PEO administration in UC model mice significantly alleviated symptoms of UC. In addition, PEO effectively suppressed colonic inflammation and oxidative stress. Mechanistically, PEO can ameliorate UC mice by modulating gut microbiota, inhibiting inflammatory targets (OPTC, PTN, IFIT3, EGFR, and TLR4), and inhibiting the PI3K-AKT pathway. Next, the 11 potential bioactive components that play a role in PEO's anti-UC mechanism were identified, and the therapeutic efficacy of the pogostone (a bioactive component) in UC mice was partially validated. CONCLUSION: This study highlights the mechanisms through which PEO can treat UC, providing a rigorous scientific foundation for future efforts to develop and apply PEO for treating UC.

Asunto(s)

Colitis Ulcerosa , Aceites Volátiles , Animales , Colitis Ulcerosa/tratamiento farmacológico , Aceites Volátiles/farmacología , Ratones , Masculino , Microbioma Gastrointestinal/efectos de los fármacos , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL , Antiinflamatorios/farmacología , Pogostemon/química , Estrés Oxidativo/efectos de los fármacos , Farmacología en Red , Colon/efectos de los fármacos , Colon/metabolismo , Colon/patología

RESUMEN

To improve paste stability of cassava starch, including acid resistance, high-temperature shear resistance and freeze-thaw stability, cassava starch was modified by sequential maltogenic amylase and transglucosidase to form an optimally denser structure, or branched density (12.76 %), molecular density (15.17 g/mol/nm3), and the proportions of short-branched chains (41.41 % of A chains and 44.01 % of B1 chains). Viscosity stability (88.52 %) of modified starch was higher than that (64.92 %) of native starch. After acidic treatment for 1 h, the viscosity of modified starch and native starch decreased by 56.53 % and 65.70 %, respectively. Compared to native starch, modified starch had lower water loss in freeze-thaw cycles and less viscosity reduction during high-temperature and high-shear processing. So, the appropriate molecular density and denser molecule structure enhanced paste stabilities of modified starch. The outcome expands the food and non-food applications of cassava starch.

Asunto(s)

Manihot , Almidón , Almidón/química , Manihot/química , Viscosidad , Glicósido Hidrolasas/química , Glicósido Hidrolasas/metabolismo , Calor , Glucosiltransferasas/química , Glucosiltransferasas/metabolismo

RESUMEN

This study examined the impact of live bread yeast (Saccharomyces cerevisiae) on the nutritional characteristics of Asian dried noodles. Micronutrient analysis of fermented noodles revealed a 6.9% increase in the overall amino acid content, a 37.1% increase in the vitamin B content and a 63.0% decrease in the phytic acid level. Molecular weight analysis of starch and protein contents revealed moderate decrease in the fermented noodles. The in vitro digestion of fermented noodles showed a slightly faster initial acidification, four-fold decrease in the initial shear viscosity (from 8.85 to 1.94 Pa·s). The initial large food particle count (>2 mm diameter) was 19.5% lower in the fermented noodles. The fermented noodles contained slightly higher free sugar content (73.5 mg g-1 noodle) during the gastric digestion phase. The overall nutrition and digestion results indicate nutritional improvement and digestion-easing attributes in the fermented noodles.

Asunto(s)

Digestión , Fermentación , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/química , Nutrientes/metabolismo , Nutrientes/análisis , Humanos , Aminoácidos/metabolismo , Aminoácidos/análisis , Pan/análisis , Pan/microbiología , Modelos Biológicos , China , Pueblos del Este de Asia

RESUMEN

Chemicals from packaging materials might be transferred into food resulting in consumer exposure. Identifying these migrated chemicals is highly challenging and crucial to perform their safety assessment, usually starting by the understanding of the chemical composition of the packaging material itself. This study explores the use of the Molecular Networking (MN) approach to support identification of the extracted chemicals. Two formulations of bioplastics were analyzed using Liquid Chromatography hyphenated to High-Resolution Mass Spectrometry. Data processing and interpretation using a conventional manual method was performed as a point of comparison to understand the power of MN. Interestingly, only the MN approach facilitated the identification of unknown chemicals belonging to a novel oligomer series containing the azelaic acid monomer. The MN approach provided a faster visualization of chemical families in addition to the highlight of unrelated chemicals enabling to prioritize chemicals for further investigation improving the safety assessment of packaging materials.

Asunto(s)

Embalaje de Alimentos , Embalaje de Alimentos/instrumentación , Contaminación de Alimentos/análisis , Espectrometría de Masas , Cromatografía Líquida de Alta Presión

RESUMEN

The storage and processing of Litopenaeus vannamei are often challenged by the freeze-thaw (F-T) cycle phenomenon. This study delved into the influence of pretreatment with l-arginine (Arg) and l-lysine (Lys) on the myofibrillar proteins oxidation and quality of shrimp subjected to F-T cycles. Arg and Lys pretreatment notably improved water-holding capacity (WHC), textural integrity as well as the myofibrillar structure of the shrimps. A lesser reduction in the amounts of immobile and bound water was found in the amino acid-treated groups, and the oxidation of lipids and proteins were both decelerated. Molecular simulation results indicated that Arg and Lys could form hydrogen and salt-bridge bonds with myosin, enhancing the stability of Litopenaeus vannamei. The study concludes that Arg and Lys are effective in alleviating the adverse effects of F-T cycles on the quality of Litopenaeus vannamei, and provides a new solution for the quality maintenance during storage and processing.

Asunto(s)

Arginina , Lisina , Proteínas Musculares , Oxidación-Reducción , Penaeidae , Animales , Penaeidae/química , Arginina/química , Lisina/química , Proteínas Musculares/química , Congelación , Conservación de Alimentos/métodos , Mariscos/análisis , Miofibrillas/química

RESUMEN

The study examined the antihypertensive effect of peptides derived from pepsin-hydrolyzed corn gluten meal, namely KQLLGY and PPYPW, and their in silico gastrointestinal tract digested fragments, KQL and PPY, respectively. KQLLGY and PPYPW showed higher angiotensin I-converting enzyme (ACE)-inhibitory activity and lower ACE inhibition constant (Ki) values when compared to KQL and PPY. Only KQL showed a mild antihypertensive effect in spontaneously hypertensive rats with -7.83 and - 5.71 mmHg systolic and diastolic blood pressure values, respectively, after 8 h oral administration. During passage through Caco-2 cells, KQL was further degraded to QL, which had reduced ACE inhibitory activity. In addition, molecular dynamics revealed that the QL-ACE complex was less stable compared to the KQL-ACE. This study reveals that structural transformation during peptide permeation plays a vital role in attenuating antihypertensive effect of the ACE inhibitor peptide.

Asunto(s)

Inhibidores de la Enzima Convertidora de Angiotensina , Antihipertensivos , Digestión , Glútenes , Péptidos , Peptidil-Dipeptidasa A , Ratas Endogámicas SHR , Zea mays , Inhibidores de la Enzima Convertidora de Angiotensina/química , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Inhibidores de la Enzima Convertidora de Angiotensina/metabolismo , Antihipertensivos/química , Antihipertensivos/farmacología , Animales , Glútenes/química , Glútenes/metabolismo , Humanos , Zea mays/química , Zea mays/metabolismo , Ratas , Células CACO-2 , Péptidos/química , Péptidos/farmacología , Masculino , Digestión/efectos de los fármacos , Peptidil-Dipeptidasa A/química , Peptidil-Dipeptidasa A/metabolismo , Presión Sanguínea/efectos de los fármacos , Hipertensión/metabolismo , Hipertensión/tratamiento farmacológico , Hipertensión/fisiopatología , Tracto Gastrointestinal/metabolismo , Hidrolisados de Proteína/química , Hidrolisados de Proteína/farmacología , Hidrólisis

RESUMEN

In this study, covalent organic frameworks (COFs) were grown in situ on magnetic nitrogen-doped graphene foam (MNGF), and the resulting composite of COFs-modified MNGF (MNC) was wrapped by molecularly imprinted polymers (MNC@MIPs) for specifically capturing SAs. A magnetic solid phase extraction (MSPE) method for SAs was established using MNC@MIPs with good magnetic responsiveness. The adsorption performance of MNC@MIPs was superior to that of non-molecularly imprinted polymers (MNC@NIPs), with shorter adsorption/desorption time and higher imprinting factors. A high-efficiency SAs analytical method was developed by fusing HPLC and MNC@MIPs-based MSPE. This approach provides excellent precision, a low detection limit, and wide linearity. By analyzing fish samples, the feasibility of the approach was confirmed, with SAs recoveries and relative standard deviations in spiked samples in the ranges of 77.2-112.7 % and 2.0-7.2 %, respectively. This study demonstrated the potential use of MNC@MIPs-based MSPE for efficient extraction and quantitation of trace hazards in food.

Asunto(s)

Peces , Contaminación de Alimentos , Estructuras Metalorgánicas , Polímeros Impresos Molecularmente , Extracción en Fase Sólida , Sulfonamidas , Extracción en Fase Sólida/métodos , Extracción en Fase Sólida/instrumentación , Animales , Polímeros Impresos Molecularmente/química , Adsorción , Contaminación de Alimentos/análisis , Estructuras Metalorgánicas/química , Sulfonamidas/aislamiento & purificación , Sulfonamidas/química , Sulfonamidas/análisis , Impresión Molecular , Polímeros/química

RESUMEN

MicroRNAs (miRNAs) play crucial roles in physiological functions and disease, but the regulation of their nuclear biogenesis remains poorly understood. Here, BioID on Drosha, the catalytic subunit of the microprocessor complex, reveals its proximity to splicing factor proline- and glutamine (Q)-rich (SFPQ), a multifunctional RNA-binding protein (RBP) involved in forming paraspeckle nuclear condensates. SFPQ depletion impacts both primary and mature miRNA expression, while other paraspeckle proteins (PSPs) or the paraspeckle scaffolding RNA NEAT1 do not, indicating a paraspeckle-independent role. Comprehensive transcriptomic analyses show that SFPQ loss broadly affects RNAs and miRNA host gene (HG) expression, influencing both their transcription and the stability of their products. Notably, SFPQ protects the oncogenic miR-17∼92 polycistron from degradation by the nuclear exosome targeting (NEXT)-exosome complex and is tightly linked with its overexpression across a broad variety of cancers. Our findings reveal a dual role for SFPQ in regulating miRNA HG transcription and stability, as well as its significance in cancers.

RESUMEN

Why are DNA bases stacked in a double helix structure? We combined three theoretical approaches to demonstrate how one core concept derived from quantum mechanics (Pauli repulsion) annihilates the contribution of dispersion to the π-π stacking. The helical architecture is governed by a combination of exchange and electrostatic forces, a result that is interpreted from both a computational and a biological perspective.

RESUMEN

OBJECTIVE: Bacterial translocation across the gut barrier has been implicated in the pathogenesis of systemic lupus erythematosus (SLE), though underlying mechanisms remain unclear. This study aimed to investigate the role of translocated bacteria in the context of molecular mimicry by utilizing lupus model mice and blood samples from untreated SLE patients. METHODS: Bacterial translocation was evaluated using nonselective cultured mesenteric lymph nodes (MLNs) from B6SKG mice, a lupus model characterized by impaired TCR signalling and gut dysbiosis. The relationships of detected pathobionts with autoantibody production were examined using in vivo experiments, enzyme-linked immunosorbent assay, immunoblotting, and epitope mapping. RESULTS: Culture-based bacterial profiling in MLNs demonstrated that Lactobacillus murinus was enriched in B6SKG mice with elevated anti-dsDNA IgG levels. Subcutaneous injection of heat-killed L. murinus induced anti-dsDNA IgG production without altering T- or B cell subset composition. Immunoblotting and mass spectrometry analysis identified a peptide ATP-binding cassette (ABC) transporter as a molecular mimicry antigen, with its cross-reactivity in lupus mice confirmed by serological assays and in vivo immunization. The L. murinus ABC transporter exhibited surface epitopes that were cross-reactive with sera from lupus mice and patients. The ABC transporter from R. gnavus, known for its pathogenic role in lupus patients, had a similar epitope sequence to that of the L. murinus ABC transporter and reacted with lupus sera. CONCLUSION: ABC transporters from gut bacteria can serve as cross-reactive antigens that may promote anti-dsDNA antibody production in genetically susceptible mice. These findings underscore the role of commensal-derived molecular mimicry and bacterial translocation in lupus pathogenesis.

RESUMEN

The adsorption/desorption characteristics of methane (CH4) on moist shale are of great significance for shale gas exploration and production. However, the influence of moisture on CH4 adsorption/desorption under high temperature and pressure conditions, which is consistent to shale reservoirs (burial depths about 3500-4500 m) in China, remained unclear. In this study, quantitative analysis toward moisture dependence of CH4 adsorption/desorption capability on shales was investigated through experimentation and molecular dynamics simulation under moisture contents of 0%, 0.204%, 0.445%, 0.677%, and 0.965%. Results show that with increasing moisture content, the isothermal adsorption capacity of CH4 decrease, and it reaches 36.80% and 10.00% at moisture content of 0.965% in experimentation and simulation, respectively. Simultaneously, the hysteresis index of CH4 desorption increase by 19.64% and 4.52%. The role of water molecules hindering CH4 desorption under low and high moisture content was clarified. At low moisture content, water molecules are mainly adsorbed on the pore walls, thereby reducing the size of the pore throat and hindering CH4 transport pathways. At high moisture content, many water molecules escape from the original adsorption sites and form clusters in the middle of the pores, blocking the pore throats. Meanwhile, CH4 is re-adsorbed onto the exposed adsorption sites of water, which leads to CH4 desorption hysteresis. The results provide valuable insights for shale gas exploration and production under practical water-bearing shale reservoir conditions.