Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 638
Filtrar
1.
Adv Mater ; : e2400976, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38740388

RESUMO

ZnSO4-based electrolytes for aqueous zinc ion batteries fail to meet practical application metrics due to hydrogen evolution reaction (HER) and dendrite growth. In this work, a highly polarized eutectic additive, glycerophosphorylcholine (GPC) is rationally designed, to regulate the electric double layer (EDL) structure for stable Zn anodes with a high depth of discharge (DOD). On one hand, GPC molecules with abundant hydroxyl groups can precisely regulate the hydrogen bond network in EDL to suppress HER. On the other hand, the enrichment of GPC at the interface is positively responsible for the negative charge density on the Zn surface, which leads to the formation of a robust ZnxPyOz-rich solid-electrolyte interphase and terminates dendrite growth in the charge-rich sites. This EDL-oriented eutectic additive engineering enables highly reversible and selectively (002)-textured Zn anodes to operate for over 1450 h at a high DOD of 45.3%. Meanwhile, a high-capacity (185.7 mAh g-1) aqueous Zn||VS2 full cell shows remarkable cycling stability over 220 cycles with an excellent capacity retention of 90.4% even at a low current density of 0.1 A g-1 (0.5 C). This work sheds light on electrolyte design and interface engineering for high-performance aqueous batteries.

2.
ACS Nano ; 18(20): 13322-13332, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38728221

RESUMO

Lead-free electrocaloric (EC) ferroelectrics are considered ideal for the next generation of environmentally friendly solid-state refrigeration materials. However, their inferior performance compared to lead-based materials significantly restricts their potential application. According to phase-field simulations, it is predicted that the pinning effect of a moderate number of defects can effectively enhance the reversible polarization response associated with the entropy change. Herein, sodium-bismuth titanate (BNT) ceramics with high spontaneous polarization are selected to construct B-site defects by introducing Li+ and Nb5+. Under an electric field of 6 kV mm-1, ultrahigh EC temperature changes of ΔTpos = 1.77 and ΔTneg = 1.49 K are achieved at 65 °C by direct measurement (ΔTneg > 1 K over 55-120 °C). Furthermore, ΔTneg remains above 0.70 K in the temperature range from 25 to 130 °C, exhibiting immense potential for practical applications. This study offers a promising direction for optimizing the EC response in defect systems.

3.
Chin Herb Med ; 16(2): 301-309, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38706827

RESUMO

Objective: A typical case of Xianling Gubao (XLGB) Tablets-induced liver injury was systematically studied in the clinic and the laboratory. Methods: A patient with herb-induced liver injury (HILI) and a history of taking XLGB Tablets before disease onset was engaged as the study subject, and the case was diagnosed according to the updated Roussel Uclaf Causality Assessment Method (RUCAM) and the integrated evidence chain (iEC) method recommended by the Guidelines for Diagnosis and Treatment of Herb-induced Liver Injury (HILI Guidelines). Results: Clinical history, biochemical indexes and imaging tests were used to exclude the influence of fundamental diseases and confusing liver diseases such as viral, alcoholic and autoimmune liver diseases on the diagnosis. Based on an investigation of the patient's medication history, she was suspected to have HILI caused by XLGB Tablets, as the patient was only taking an oral preparation of XLGB Tablets, and the influence of other drugs on the diagnosis was excluded. This patient with alanine aminotransferase (ALT) ≥ 3 × upper limit of normal (ULN) and a calculated R of 6 was diagnosed with possible acute drug-induced hepatocellular injury. The relationship was considered "highly probable" (score of 9) using the updated RUCAM of 2016. Moreover, the fingerprint similarity between the preparation taken by the patient and a commercially available preparation was 0.99, suggesting that the patient was consuming XLGB Tablets rather than another drug. LC-MS technology and the Agilent Fake TCM-Drugs database were used to investigate the drug, and no chemical additions were found. Examination of the drug for pesticide residues, heavy metals, aflatoxins and other exogenous substances indicated compliance with the content limits of the Chinese Pharmacopoeia. Conclusion: In summary, the final diagnosis of XLGB-induced liver injury reached the clinical diagnosis of HILI and was acute severe hepatocellular injury type by the updated RUCAM and iEC. Therefore, this study provides scientific evidence regarding the causality evaluation of compound preparations of traditional Chinese medicines-induced liver injury.

4.
BMC Genom Data ; 25(1): 41, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38711007

RESUMO

BACKGROUND: Class III peroxidase (POD) enzymes play vital roles in plant development, hormone signaling, and stress responses. Despite extensive research on POD families in various plant species, the knowledge regarding the POD family in Chinese pear (Pyrus bretschenedri) is notably limited. RESULTS: We systematically characterized 113 POD family genes, designated as PbPOD1 to PbPOD113 based on their chromosomal locations. Phylogenetic analysis categorized these genes into seven distinct subfamilies (I to VII). The segmental duplication events were identified as a prevalent mechanism driving the expansion of the POD gene family. Microsynteny analysis, involving comparisons with Pyrus bretschenedri, Fragaria vesca, Prunus avium, Prunus mume and Prunus persica, highlighted the conservation of duplicated POD regions and their persistence through purifying selection during the evolutionary process. The expression patterns of PbPOD genes were performed across various plant organs and diverse fruit development stages using transcriptomic data. Furthermore, we identified stress-related cis-acting elements within the promoters of PbPOD genes, underscoring their involvement in hormonal and environmental stress responses. Notably, qRT-PCR analyses revealed distinctive expression patterns of PbPOD genes in response to melatonin (MEL), salicylic acid (SA), abscisic acid (ABA), and methyl jasmonate (MeJA), reflecting their responsiveness to abiotic stress and their role in fruit growth and development. CONCLUSIONS: In this study, we investigated the potential functions and evolutionary dynamics of PbPOD genes in Pyrus bretschenedri, positioning them as promising candidates for further research and valuable indicators for enhancing fruit quality through molecular breeding strategies.


Assuntos
Regulação da Expressão Gênica de Plantas , Filogenia , Reguladores de Crescimento de Plantas , Pyrus , Pyrus/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Reguladores de Crescimento de Plantas/metabolismo , Melatonina/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Oxilipinas/farmacologia , Ciclopentanos/farmacologia , Peroxidase/genética , Peroxidase/metabolismo , Acetatos/farmacologia , Acetatos/metabolismo , Frutas/genética , Frutas/crescimento & desenvolvimento
5.
Chin Med ; 19(1): 67, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38720376

RESUMO

BACKGROUND: Thesium chinense Turcz. (Named as Bai Rui Cao in Chinese) and its preparations (e.g., Bairui Granules) have been used to treat inflammatory diseases, such as acute mastitis, lobar pneumonia, tonsillitis, coronavirus disease 2019 (COVID-19), and upper respiratory tract infection. However, the material basis, pharmacological efficiency, and safety have not been illustrated. METHODS: Anti-inflammatory activity-guided isolation of constituents has been performed using multiple column chromatography, and their structures were elucidated by NMR spectroscopy and ECD calculations. The inhibitory effects on lung inflammation and safety of the crude ethanol extract (CE), Bairui Granules (BG), and the purified active constituents were evaluated using lipopolysaccharide (LPS)-stimulated acute lung inflammation (ALI) mice model or normal mice. RESULTS: Seven new compounds (1-7) and fifty-six known compounds (8-63) were isolated from T. chinense, and fifty-four were reported from this plant for the first time. The new flavonoid glycosides 1-2, new fatty acids 4-5, new alkaloid 7 as well as the known constituents including flavonoid aglycones 8-11, lignans 46-54, alkaloids 34 and 45, coumarins 57, phenylpropionic acids 27, and simple aromatic compounds 39, 44 and 58 exhibited anti-inflammatory activity. Network pharmacology analysis indicated that anti-inflammation of T. chinense was attributed to flavonoids and alkaloids by regulating inflammation-related proteins (e.g., TNF, NF-κB, TGF-ß). Furthermore, constituents of T. chinense including kaempferol-3-O-glucorhamnoside (KN, also named as Bairuisu I, 19), astragalin (AG, Bairuisu II, 12), and kaempferol (KF, Bairuisu III, 8), as well as CE and BG could alleviate lung inflammation caused by LPS in mice by preventing neutrophils infiltration and the expression of the genes for pro-inflammatory cytokines NLRP3, caspase-1, IL-1ß, and COX-2. After a 28-day subacute toxicity test, BG at doses of 4.875 g/kg and 9.750 g/kg (equivalent to onefold and twofold the clinically recommended dose) and CE at a dose of 11.138 g/kg (equivalent to fourfold the clinical dose of BG) were found to be safe and non-toxic. CONCLUSIONS: The discovery of sixty-three constituents comprehensively illustrated the material basis of T. chinense. T. chinense and Bairui Granules could alleviate lung inflammation by regulating inflammation-related proteins and no toxicity was observed under the twofold of clinically used doses.

6.
Nat Commun ; 15(1): 3683, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38693101

RESUMO

Hindered ethers are ubiquitous in natural products and bioactive molecules. However, developing an efficient method for the stereocontrolled synthesis of all stereoisomers of chiral hindered ethers is highly desirable but challenging. Here we show a strategy that utilizes in situ-generated water as a nucleophile in an asymmetric cascade reaction involving two highly reactive intermediates, 3-furyl methyl cations and ortho-quinone methides (o-QMs), to synthesize chiral hindered ethers. The Ca(II)/Au(I) synergistic catalytic system enables the control of diastereoselectivity and enantioselectivity by selecting suitable chiral phosphine ligands in this cascade hydration/1,4-addition reaction, affording all four stereoisomers of a diverse range of chiral tetra-aryl substituted ethers with high diastereoselectivities (up to >20/1) and enantioselectivities (up to 95% ee). This work provides an example of chiral Ca(II)/Au(I) bimetallic catalytic system controlling two stereogenic centers via a cascade reaction in a single operation.

7.
Animals (Basel) ; 14(9)2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38731386

RESUMO

The utilization of chicken embryonic-derived pluripotent stem cell (PSC) lines is crucial in various fields, including growth and development, vaccine and protein production, and germplasm resource protection. However, the research foundation for chicken PSCs is relatively weak, and there are still challenges in establishing a stable and efficient PSC culture system. Therefore, this study aims to investigate the effects of the FGF2/ERK and WNT/ß-catenin signaling pathways, as well as different feeder layers, on the derivation and maintenance of chicken embryonic-derived PSCs. The results of this study demonstrate that the use of STO cells as feeder layers, along with the addition of FGF2, IWR-1, and XAV-939 (FIX), allows for the efficient derivation of chicken PSC-like cells. Under the FIX culture conditions, chicken PSCs express key pluripotency genes, such as POUV, SOX2, and NANOG, as well as specific proteins SSEA-1, C-KIT, and SOX2, indicating their pluripotent nature. Additionally, the embryoid body experiment confirms that these PSC-like cells can differentiate into cells of three germ layers in vitro, highlighting their potential for multilineage differentiation. Furthermore, this study reveals that chicken Eyal-Giladi and Kochav stage X blastodermal cells express genes related to the primed state of PSCs, and the FIX culture system established in this research maintains the expression of these genes in vitro. These findings contribute significantly to the understanding and optimization of chicken PSC culture conditions and provide a foundation for further exploration of the biomedical research and biotechnological applications of chicken PSCs.

8.
Adv Sci (Weinh) ; : e2306348, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38696655

RESUMO

Patients who have non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations are more prone to brain metastasis (BM) and poor prognosis. Previous studies showed that the tumor microenvironment of BM in these patients is immunosuppressed, as indicated by reduced T-cell abundance and activity, although the mechanism of this immunosuppression requires further study. This study shows that reactive astrocytes play a critical role in promoting the immune escape of BM from EGFR-mutated NSCLC by increasing the apoptosis of CD8+ T lymphocytes. The increased secretion of interleukin 11(IL11) by astrocytes promotes the expression of PDL1 in BM, and this is responsible for the increased apoptosis of T lymphocytes. IL11 functions as a ligand of EGFR, and this binding activates EGFR and downstream signaling to increase the expression of PDL1, culminating in the immune escape of tumor cells. IL11 also promotes immune escape by binding to its intrinsic receptor (IL11Rα/glycoprotein 130 [gp130]). Additional in vivo studies show that the targeted inhibition of gp130 and EGFR suppresses the growth of BM and prolongs the survival time of mice. These results suggest a novel therapeutic strategy for treatment of NSCLC patients with EGFR mutations.

9.
Physiol Mol Biol Plants ; 30(4): 527-542, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38737319

RESUMO

The TIFY family consists of plant-specific genes that regulates multiple plant functions, including developmental and defense responses. Here, we performed a comprehensive genomic analysis of TIFY genes in Dendrobium huoshanense. Our analysis encompassed their phylogenetic relationships, gene structures, chromosomal distributions, promoter regions, and patterns of collinearity. A total of 16 DhTIFY genes were identified, and classified into distinct clusters named JAZ, PPD, ZIM, and TIFY based on their phylogenetic relationship. These DhTIFYs exhibited an uneven distribution across 7 chromosomes. The expansion of the DhTIFY gene family appears to have been significantly influenced by whole-genome and segmental duplication events. The ratio of non-synonymous to synonymous substitutions (Ka/Ks) implies that the purifying selection has been predominant, maintaining a constrained functional diversification after duplication events. Gene structure analysis indicated that DhTIFYs exhibited significant structural variation, particularly in terms of gene organization and intron numbers. Moreover, numerous cis-acting elements related to hormone signaling, developmental processes, and stress responses were identified within the promoter regions. Subsequently, qRT-PCR experiments demonstrated that the expression of DhTIFYs is modulated in response to MeJA (Methyl jasmonate), cold, and drought treatment. Collectively, these results enhance our understanding of the functional dynamics of TIFY genes in D. huoshanense and may pinpoint potential candidates for detailed examination of the biological roles of TIFY genes. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-024-01442-9.

10.
ACS Appl Mater Interfaces ; 16(19): 25385-25392, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38690867

RESUMO

In the endeavor to develop advanced photodetectors (PDs) with superior performance, all-inorganic perovskites, recognized for their outstanding photoelectric properties, have emerged as highly promising materials. Due to their unique electronic structure and band characteristics, the majority of all-inorganic perovskite materials are not sensitive to near-infrared (NIR) light. Here, we demonstrate the fabrication of a high-performance broadband PD comprising CsPbBr3 perovskite NCs/Y6 planar heterojunctions. The incorporation of Y6 not only facilitates charge transfer from CsPbBr3 NCs to Y6 for enhancing photodetection performance under visible illumination but also broadens the absorption spectrum range of the whole device toward the NIR regime. As a result, the heterojunction PD exhibits a photo-to-dark-current ratio above 105, a dynamic range of 149.5 dB, and an impressive lowest detection limit of incident power density of 1.6 nW/cm2 under 505 nm illumination. In the NIR regime, where photon energy is below the bandgap of CsPbBr3, electron-hole pairs can still be produced in the Y6 layer even when illuminated at 1120 nm. Consequently, photodetection is uniquely possible in PDs that incorporate heterojunctions when the illumination wavelength is longer than 565 nm. At 850 nm, the heterojunction device is capable of detecting light with power densities as low as 1.3 µW/cm2 corresponding to a LDR of 99.8 dB. The exceptional performance is attributed to the creation of a heterojunction between CsPbBr3 NCs and Y6. These findings propose a novel approach for developing broadband PDs based on perovskite NC materials.

11.
Schizophr Bull ; 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38581275

RESUMO

BACKGROUND AND HYPOTHESIS: Despite the well-documented structural and functional brain changes in schizophrenia, the potential role of glymphatic dysfunction remains largely unexplored. This study investigates the glymphatic system's function in schizophrenia, utilizing diffusion tensor imaging (DTI) to analyze water diffusion along the perivascular space (ALPS), and examines its correlation with clinical symptoms. STUDY DESIGN: A cohort consisting of 43 people with schizophrenia and 108 healthy controls was examined. We quantified water diffusion metrics along the x-, y-, and z-axis in both projection and association fibers to derive the DTI-ALPS index, a proxy for glymphatic activity. The differences in the ALPS index between groups were analyzed using a 2-way ANCOVA controlling for age and sex, while partial correlations assessed the association between the ALPS index and clinical variables. STUDY RESULTS: People with schizophrenia showed a significantly reduced DTI-ALPS index across the whole brain and within both hemispheres (F = 9.001, P = .011; F = 10.024, P = .011; F = 5.927, P = .044; false discovery rate corrected), indicating potential glymphatic dysfunction in schizophrenia. The group by cognitive performance interaction effects on the ALPS index were not observed. Moreover, a lower ALPS index was associated with poorer cognitive performance on specific neuropsychological tests in people with schizophrenia. CONCLUSION: Our study highlights a lower ALPS index in schizophrenia, correlated with more pronounced cognitive impairments. This suggests that glymphatic dysfunction may contribute to the pathophysiology of schizophrenia, offering new insights into its underlying mechanisms.

12.
Adv Sci (Weinh) ; : e2307779, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38569221

RESUMO

Acid-induced arginine decarboxylase AdiA is a typical homo-oligomeric protein biosynthesizing alkaline nylon monomer putrescine. However, upon loss of the AdiA decamer oligomeric state at neutral and alkaline conditions the activity also diminishes, obstructing the whole-cell biosynthesis of alkaline putrescine. Here, a structure cohesion strategy is proposed to change the pH adaptation of AdiA to alkaline environments based on the rational engineering of meridional and latitudinal oligomerization interfaces. After integrating substitutions of E467K at the latitudinal interface and H736E at the meridional channel interface, the structural stability of AdiA decamer and its substrate transport efficiency at neutral and alkaline conditions are improved. Finally, E467K_H736E is well adapted to neutral and alkaline environments (pH 7.0-9.0), and its enzymatic activity is 35-fold higher than that of wild AdiA at pH 8.0. Using E467K_H736E in the putrescine synthesis pathway, the titer of putrescine is up to 128.9 g·L-1 with a conversion of 0.94 mol·mol-1 in whole-cell catalysis. Additionally, the neutral pH adaptation of lysine decarboxylase, with a decamer structure similar to AdiA, is also improved using this cohesion strategy, providing an option for pH-adaptation engineering of other oligomeric decarboxylases.

13.
Angew Chem Int Ed Engl ; : e202403607, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38659136

RESUMO

Alkaline zinc-ferricyanide flow batteries are efficiency and economical as energy storage solutions. However, they suffer from low energy density and short calendar life. The strongly alkaline conditions (3 mol L-1 OH-) reduce the solubility of ferri/ferro-cyanide (normally only 0.4 mol L-1 at 25 oC) and induce the formation of zinc dendrites at the anode. Here, we report a new zinc-ferricyanide flow battery based on a mild alkalescent (pH 12) electrolyte. Using a chelating agent to rearrange ferri/ferro-cyanide ion-solvent interactions and improve salt dissociation, we increased the solubility of ferri/ferro-cyanide to 1.7 mol L-1 and prevented zinc dendrites. Our battery has an energy density of ~74 Wh L-1 at 60 oC and remains stable for 1800 cycles (1800 hours) at 0 oC and for >1400 cycles (2300 hours) at 25 oC. An alkalescent zinc-ferricyanide cell stack built using this alkalescent electrolyte stably delivers 608 W of power for ~40 days.

14.
J Am Chem Soc ; 146(15): 10257-10262, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38578111

RESUMO

Sorption-based atmospheric water harvesting (AWH) is a promising solution for addressing water scarcity. Developing cost-effective and stable water adsorbents with high water uptake capacity and a low-temperature regeneration requirement is a crucially important procedure. In this Communication, we present a novel and stable aluminophosphate (AlPO) molecular sieve (MS) named DNL-11 with 16-ring channels synthesized by using an affordable and commercialized organic structure directing agent (OSDA), whose crystallographic structure is elucidated by three-dimensional electron diffraction (3D ED). DNL-11 exhibits a significant water uptake capacity (189 mg/g) at a very low vapor pressure (5% relative humidity at 30 °C). In addition, most of the adsorbed water can be effortlessly removed by purging N2 at 25 °C under ambient pressure conditions. This may expand the possibility of AWH under extreme drought conditions.

15.
Ethn Health ; : 1-12, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38682471

RESUMO

OBJECTIVES: This study aimed to examine ethnic disparities in the prevalence of diabetes and its association with sleep disorders among the older adults Han and ethnic minority (Bai, Ha Ni, and Dai) population in rural southwest China. METHODS: A cross-sectional survey of 5,642 was conducted among the rural southwest population aged ≥60 years, consisting of a structured interview and measurement of fasting blood glucose, height, weight, and waist circumference. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. RESULTS: The overall prevalence of diabetes and sleep disorder was 10.2% and 40.1%, respectively. Bai participants had the highest prevalence of diabetes (15.9%) and obesity (9.9%)(P < 0.01), while Ha Ni participants had the lowest prevalence of diabetes (5.1%) and obesity (3.4%)(P < 0.01). The highest prevalence of sleep disorder (48.4%) was recorded in Bai participants, while Dai participants had the lowest prevalence of sleep disorder (25.6%)(P < 0.01). In all four studied ethnicities, females had a higher prevalence of sleep disorder than males (P < 0.01), and the prevalence of sleep disorder increased with age (P < 0.01). The results of multivariate logistic regression analysis indicated older adults with sleep disorder had a risk of developing diabetes (P < 0.05). Moreover, the higher educational level, family history of diabetes, and obesity were the main risk factors for diabetes in participants (P < 0.01). CONCLUSION: There are stark ethnic disparities in the prevalence of diabetes and sleep disorders in southwest China. Future diabetes prevention and control strategies should be tailored to address ethnicity, and improving sleep quality may reduce the prevalence of diabetes.

17.
ACS Appl Mater Interfaces ; 16(17): 22361-22368, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38628106

RESUMO

Spin-coated quasi-two-dimensional halide perovskite films, which exhibit superior optoelectronic properties and environmental stability, have recently been extensively studied for lasers. Crystallinity is of great importance for the laser performance. Although some parameters related to the spin-coating process have been studied, the in-depth understanding and effective control of the acceleration rate on two-dimensional perovskite crystallization during spin-coating are still unknown. Here we investigate the effect of solvent evaporation on the microstructure of the final perovskite films during the spin-coating process. The crystallization quality of the film can be significantly improved by controlling solvent evaporation. As a result, the prepared quasi-2D perovskite film exhibits a stimulated emission threshold (pump: 343 nm, 6 kHz, 290 fs) of 550 nm as low as 16.2 µJ/cm2. Transient absorption characterization shows that the radiative biexciton recombination time is reduced from 738.5 to 438.3 ps, benefiting from the improved crystallinity. The faster biexciton recombination significantly enhanced the photoluminescence efficiency, which is critical for population inversion. This work could contribute to the development of low-threshold lasers.

18.
J Am Chem Soc ; 146(11): 7628-7639, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38456823

RESUMO

High binding affinity and selectivity of metal ions are essential to the function of metalloproteins. Thus, understanding the factors that determine these binding characteristics is of major interest for both fundamental mechanistic investigations and guiding of the design of novel metalloproteins. In this work, we perform QM cluster model calculations and quantum mechanics/molecular mechanics (QM/MM) free energy simulations to understand the binding selectivity of Ca2+ and Mg2+ in the wild-type carp parvalbumin and its mutant. While a nonpolarizable MM model (CHARMM36) does not lead to the correct experimental trend, treatment of the metal binding site with the DFTB3 model in a QM/MM framework leads to relative binding free energies (ΔΔGbind) comparable with experimental data. For the wild-type (WT) protein, the calculated ΔΔGbind is ∼6.6 kcal/mol in comparison with the experimental value of 5.6 kcal/mol. The good agreement highlights the value of a QM description of the metal binding site and supports the role of electronic polarization and charge transfer to metal binding selectivity. For the D51A/E101D/F102W mutant, different binding site models lead to considerable variations in computed binding affinities. With a coordination number of seven for Ca2+, which is shown by QM/MM metadynamics simulations to be the dominant coordination number for the mutant, the calculated relative binding affinity is ∼4.8 kcal/mol, in fair agreement with the experimental value of 1.6 kcal/mol. The WT protein is observed to feature a flexible binding site that accommodates a range of coordination numbers for Ca2+, which is essential to the high binding selectivity for Ca2+ over Mg2+. In the mutant, the E101D mutation reduces the flexibility of the binding site and limits the dominant coordination number of Ca2+ to be seven, thereby leading to reduced binding selectivity against Mg2+. Our results highlight that the binding selectivity of metal ions depends on both the structural and dynamical properties of the protein binding site.


Assuntos
Proteínas de Ligação ao Cálcio , Metaloproteínas , Sítios de Ligação , Ligação Proteica , Metaloproteínas/química , Íons
19.
Sci Total Environ ; 926: 171820, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38513857

RESUMO

Atmospheric brown carbon (BrC) aerosols were investigated at two urban sites in southern (Hefei) and northern (Shijiazhuang) China during summer and winter of 2019-2020 to explore regional variability in their compositional and optical properties. Organic matter in ambient PM2.5 samples were characterized at molecular level using ultrahigh performance liquid chromatography coupled with a diode array detector and an Orbitrap mass spectrometer. Although the molecular composition of organic aerosols varied substantially over different ambient environments, they were mainly composed by CHO and CHON species in positive ionization mode while CHO and CHOS species in negative mode. The mass absorption coefficients of BrC aerosols at wavelength range 250-450 nm were relatively higher for winter samples in both cities and for Shijiazhuang samples in both seasons, partly attributed to the higher concentration levels of anthropogenic air pollutants in these environments. The absorption Ångström exponents further revealed that BrC aerosols in winter seasons and in Shijiazhuang had a greater capacity of absorption at shorter wavelengths. A total of 26 BrC species with strong absorption were unambiguously identified from different environments, which mainly consisted of CHO, CHON, and CHN species and had higher degrees of unsaturation and lower degrees of oxidation. The presence and abundance of these BrC species varied dynamically across the seasons and cities, with a greater number of species presented in the winter of Shijiazhuang. The BrC species together contributed 12-26 % in the total absorbance of light-absorbing organic components at 250-450 nm. This study highlights the regional differences in BrC properties influenced by the sources and atmospheric processes, which should be taken into account to assess their climate impacts.

20.
Int Immunopharmacol ; 131: 111799, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38460297

RESUMO

The application of immune checkpoint inhibitors (ICIs) has made extraordinary achievements in tumor treatment. Among them, programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors can improve the prognosis of advanced tumors, and have been widely used in clinical practice to treat many types of cancers. However, excessive immune response can also induce immune-related adverse events (irAEs) involving many organs. Of these, immune-related liver injury is the relatively common and carries the highest morbidity, which has attracted the attention of hepatologists all over the world. The incidence of this type of liver injury depends specifically on factors such as the type of drug being combined, viral infection, type of cancer and liver transplantation. Although there is no unanimity on the mechanism of PD-1/PD-L1 inhibitor-induced liver injury, in this review, we also summarize the current evidence that provides insights into the pathogenesis of PD-1/PD-L1 inhibitor-induced liver injury, including the fact that PD-1/PD-L1 inhibitors cause reactivation of CTLs, aberrant presentation of autoantigens, hepatic immune tolerance environment is disrupted, and cytokine secretion, among other effects. Patients usually develop liver injury after the use of PD-1/PD-L1 inhibitors, and clinical symptoms mainly include weakness, muscle pain, nausea and vomiting, and jaundice. Histologically, the main manifestation is lobular hepatitis with lobular inflammatory infiltration. Since the specific biomarkers for PD-1/PD-L1 inhibitor-associated liver injury have not been identified yet, alpha-fetoprotein, IL-6, and IL-33 have the potential to be biomarkers for predicting this type of liver injury in the future, but this requires further research. We also describe the examination and treatment of this type of liver injury, which usually includes eliminating related influencing factors, regularly monitoring liver function, temporarily retaining or permanently stopping ICIs treatment according to the severity of toxicity, and using corticosteroids. This review may provide useful information for the future clinical practice of PD-1/PD-L1 inhibitors.


Assuntos
Doença Hepática Crônica Induzida por Substâncias e Drogas , Neoplasias , Humanos , Inibidores de Checkpoint Imunológico/efeitos adversos , Imunoterapia/efeitos adversos , Receptor de Morte Celular Programada 1
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...