Mycobacterium tuberculosis VII secretion system effector molecule Rv2347c blocks the maturation of phagosomes and activates the STING/TBK1 signaling pathway to inhibit cell autophagy.

The VII secretion system is the main channel for Mycobacterium tuberculosis (MTB) to secrete virulence proteins. The ESAT-like proteins EsxA/B and EsxW/V in the RD region of its genome have been used as targets for vaccine antigens. However, the function of EsxO/P has not been explored, although it was predicted to potentially induce Th1 cell responses as a vaccine development target. In this study, the VII secretion system effector molecule Rv2347c was heterologously expressed in Mycobacterium smegmatis and found to inhibit the expression of the early marker RAB5 of phagosomes, thus preventing the maturation process of phagosomes toward lysosomes, and activated the host cytoplasmic sensing pathway. It inhibited autophagy and activated IFNß transcription through the STING/TBK1 pathway promoting the host's survival. Therefore, Rv2347c plays an important role in the pathogenesis of MTB with the potential to be utilized as a new target for tuberculosis vaccine development. IMPORTANCE: We found that the ESAT-like protein Rv2347c (EsxP) can inhibit the maturation of phagosomes, leading to mycobacterium escape from phagosomes into the cytoplasm, which triggers the host's cytoplasmic sensing pathway STING/TBK1, inhibiting autophagy and upregulating IFNß transcription, which contributes to the survival of mycobacterium in the host cell. We also found that Rv2347c was able to activate host immunity by activating NF-κB via STING and promoting the transcription of downstream pro-inflammatory factors. Meanwhile, the host also produces IL-1ß to repair phagosome maturation arrest via the STING-mediated non-NF-κB pathway.

DBAII-Net with multiscale feature aggregation and cross-modal attention for enhancing infant brain injury classification in MRI.

OBJECTIVES: MRI is pivotal in diagnosing brain injuries in infants. However, the dynamic development of the brain introduces variability in infant MRI characteristics, posing challenges for MRI-based classification in this population. Furthermore, manual data selection in large-scale studies is labor-intensive, and existing algorithms often underperform with thick-slice MRI data. To enhance research efficiency and classification accuracy in large datasets, we propose an advanced classification model. APPROACH: We introduce the Dual-Branch Attention Information Interactive Neural Network (DBAII-Net), a cutting-edge model inspired by radiologists' use of multiple MRI sequences. DBAII-Net features two innovative modules: (1) the Convolutional Enhancement Module (CEM), which leverages advanced convolutional techniques to aggregate multi-scale features, significantly enhancing information representation; and (2) the Cross-Modal Attention Module (CMAM), which employs state-of-the-art attention mechanisms to fuse data across branches, dramatically improving positional and channel feature extraction. Performances (accuracy, sensitivity, specificity, area under the curve, etc.) of DBAII-Net were compared with eight benchmark models for brain MRI classification in infants aged 6 months to 2 years. MAIN RESULTS: Utilizing a self-constructed dataset of 240 thick-slice brain MRI scans (122 with brain injuries, 118 without), DBAII-Net demonstrated superior performance. On a test set of approximately 50 cases, DBAII-Net achieved average performance metrics of 92.53% accuracy, 90.20% sensitivity, 94.93% specificity, and an area under the curve (AUC) of 0.9603. Ablation studies confirmed the effectiveness of CEM and CMAM, with CMAM significantly boosting classification metrics. SIGNIFICANCE: DBAII-Net with CEM and CMAM outperforms existing benchmarks in enhancing the precision of brain MRI classification in infants, significantly reducing manual effort in infant brain research. Our code is available at https://github.com/jiazhen4585/DBAII-Net.

The mitochondrial function of peripheral blood mononuclear cells in frail older patients.

BACKGROUND: Frailty increases the incidence of geriatric syndromes and even the risk of death in old adults. However, the diagnostic criteria for frailty are inconsistent because of complex pathological processes and diverse clinical manifestations. To determine the effective biomarker and recognize frail status early, we investigated the correlation of mitochondrial morphology and function of human peripheral blood mononuclear cells (PBMCs) with frailty status in older adults. METHODS: This Cross-sectional study followed 393 participants (aged 25-100 years, female 31.04 %) from the First Affiliated Hospital of Nanjing Medical University. The frailty status of subjects was assessed by the physical frailty phenotype (PFP) scale. We analyzed mitochondria functions including mitochondria copy number (mtDNAcn), the mRNA expressions of mitochondrial dynamics-related genes mitofusin 1(MFN1), mitofusin 2(MFN2), optic atrophy protein-1(OPA1), fission protein-1(FIS1) and dynamin-related protein 1(DRP1), mitochondrial oxidative respiration and reactive oxygen species(ROS) levels in PBMCs. Mitochondria morphology, size, and number were observed by transmission electron microscopy (TEM). RESULTS: After adjustment for sex and BMI, mtDNAcn, the mRNA expression of FIS1, mitochondrial respiratory function (proton leak, maximum oxygen consumption, and respiratory reserve) and ROS level were significantly correlated with age (P = 0.031, 0.030, 0.042, 0.003, 0.002, 0.022, respectively). After correcting for age, sex, and BMI, mtDNAcn and the mRNA expression of OPA1 were correlated with 4 m gait speed respectively (P = 0.003, 0.028, respectively). Compared with non-frail people, mtDNAcn, the mRNA expression of MFN1, mitochondrial basal respiration, proton leak, maximum oxygen consumption, ATP production and space capacity were significantly decreased in frail older adults (P = 0.013, 0.036, 0.026, 0.024, 0.012, 0.029, 0.032, 0.020, respectively). ROS levels were significantly increased in the frail group (P = 0.016). Compared with non-frail people, the number, length, and perimeter, area of mitochondria were reduced in frail group under TEM (all P < 0.001). CONCLUSION: Mitochondrial dysfunctions (decreased mtDNAcn, impaired mitochondrial morphology, imbalanced mitochondrial dynamic, impaired mitochondrial respiratory function, and increased ROS levels) were significantly correlated with frail status.

Efficient circularly polarized multiple resonance thermally activated delayed fluorescence from B,N-embedded hetero[8]helicene enantiomers.

Helicene-based circularly polarized multiple resonance thermally activated delayed fluorescence (CP-MR-TADF) materials are promising for ultra-high-definition and 3D displays, but most of them encounter potential problems such as easy racemization during the thermal deposition process, low luminous efficiency, and low luminescence dissymmetry factor (g lum), making the development of efficient circularly polarized organic light-emitting diodes (CP-OLEDs) a significant challenge. Here, we report a pair of CP-MR-TADF enantiomers with high-order B,N-embedded hetero[8]helicene, (P/M)-BN-TP-ICz, by fusing two MR chromophores, DtCzB and indolo[3,2,1-jk]carbazole (ICz). BN-TP-ICz exhibits green emission in toluene with a peak of 531 nm and a full-width at half-maximum (FWHM) of 36 nm. The optimized CP-OLEDs with enantiomers (P/M)-BN-TP-ICz exhibit green emission with peaks of 540 nm, FWHMs of 38 nm and Commission Internationale de L'Eclairage coordinates of (0.33, 0.65). Moreover, they showcase maximum external quantum efficiencies (EQEs) of 32.0%, with g ELs of +6.49 × 10-4 and -7.74 × 10-4 for devices based on (P)-BN-TP-ICz- and (M)-BN-TP-ICz, respectively.

The tomato WRKY-B transcription factor modulates lateral branching by targeting BLIND, PIN4, and IAA15.

Lateral branching is a crucial agronomic trait that impacts crop yield. In tomato ( Solanum lycopersicum ), excessive lateral branching is unfavorable and results in substantial labor and management costs. Therefore, optimizing lateral branching is a primary objective in tomato breeding. Although many genes related to lateral branching have been reported in tomato, the molecular mechanism underlying their network remains elusive. In this study, we found that the expression profile of a WRKY gene, WRKY-B (for WRKY-BRANCING), was associated with the auxin-dependent axillary bud development process. Wrky-b mutants generated by the CRISPR/Cas9 editing system presented fewer lateral branches, while WRKY-B overexpression lines presented more lateral branches than did wild-type plants. Furthermore, WRKY-B can directly target the well-known branching gene BLIND (BL) and the auxin efflux carrier gene PIN4 to activate their expression. Both the bl and pin4 mutants exhibited reduced lateral branching, similar to the wrky-b mutant. The IAA contents in the axillary buds of the wrky-b, bl, and pin4 mutant plants were significantly higher than those in the wild-type plants. In addition, WRKY-B can also directly target the AUX/IAA gene IAA15 and repress its expression. In summary, WRKY-B works upstream of BL, PIN4, and IAA15 to regulate the development of lateral branches in tomato.

Traditional Chinese Medicine in the treatment of chronic atrophic gastritis, precancerous lesions and gastric cancer.

ETHNOPHARMACOLOGICAL RELEVANCE: Chronic atrophic gastritis (CAG), precancerous lesions of gastric cancer (PLGC), and gastric cancer (GC), seriously threaten human health. Traditional Chinese medicine (TCM) has been employed in the treatment of chronic diseases for a long time and has shown remarkable efficacy. AIM OF THE STUDY: Recently, there has been an increasing use of TCM in treating CAG, PLGC, and GC. The objective of this study is to compile a comprehensive overview of the existing research on the effects and molecular mechanisms of TCM, including formulas, single herbs, and active components. MATERIALS AND METHODS: To obtain a comprehensive understanding of traditional use of TCM in treating these diseases, we reviewed ancient books and Chinese literature. In addition, keywords such as "TCM", "CAG", "PLGC", "GC", and "active ingredients" were used to collect modern research on TCM published in databases such as CNKI, Web of Science, and Pubmed up to April 2024. All collected information was then summarized and analyzed. RESULTS: This study analyzed 174 articles, which covered the research progress of 20 TCM formulas, 14 single herbs, and 50 active ingredients in treating CAG, PLGC, and GC. Sources, effects, and molecular mechanisms of the TCM were summarized. CONCLUSIONS: This article reviews the progress of TCM in the management of CAG, PLGC, and GC, which will provide a foundation for the clinical application and further development of TCM.

Modularly Precise Construction of B,N-Embedded Large-Sized Polycyclic Aromatic Hydrocarbon Nanographene.

A modular "fjord-stitching" reverse strategy has been disclosed to successfully prepare two large-sized B,N-embedded nanographenes: BN-TBTi and BN-TBTo. These two compounds both exhibit excellent stability, nonzero-bandgap and decent photoluminescence quantum yield. Single crystal structure of BN-TBTo features a large C78B2N4 π-skeleton with length and width of approximately 2.4 and 1.5 nm, respectively.

Mycobacterium LacI-type Transcription Regulator Rv3575c Affects Host Innate Immunity by Regulating Bacterial mce4 Operon-Mediated Cholesterol Transport.

Mycobacterium tuberculosis has evolved a highly specialized system to snatch essential nutrients from its host, among which host-derived cholesterol has been established as one main carbon source for M. tuberculosis to survive within granulomas. The uptake, catabolism, and utilization of cholesterol are important for M. tuberculosis to sustain within the host largely via remodeling of the bacterial cell walls. However, the regulatory mechanism of cholesterol uptake and its impact on bacterium fate within infected hosts remain elusive. Here, we found that M. tuberculosis LacI-type transcription regulator Rv3575c negatively regulates its mce4 family gene transcription. Overexpression of Rv3575c impaired the utilization of cholesterol as the sole carbon source by Mycobacterium smegmatis, activating the host's innate immune response and triggering cell pyroptosis. The M. smegmatis homologue of Rv3575c MSMEG6044 knockout showed enhanced hydrophobicity and permeability of the cell wall and resistance to ethambutol, suppressed the host innate immune response to M. smegmatis, and promoted the survival of M. smegmatis in macrophages and infected mouse lungs, leading to reduced transcriptional levels of TNFα and IL-6. In summary, these data indicate a role of Rv3575c in the pathogenesis of mycobacteria and reveal the key function of Rv3575c in cholesterol transport in mycobacteria.

Brain border-derived CXCL2+ neutrophils drive NET formation and impair vascular reperfusion following ischemic stroke.

BACKGROUND: The brain border compartments harbor a diverse population of immune cells and serve as invasion sites for leukocyte influx into the brain following CNS injury. However, how brain-border myeloid cells affect stroke pathology remains poorly characterized. METHODS AND RESULTS: Here, we showed that ischemic stroke-induced expansion of CXCL2+ neutrophils, which exhibit highly proinflammatory features. We tracked CXCL2+ neutrophils in vivo by utilizing a photoconvertible Kik-GR mouse (fluorescent proteins Kikume Green Red, Kik-GR) and found that brain-infiltrating CXCL2+ neutrophils following ischemic stroke were mainly derived from the brain border rather than the periphery. We demonstrated that CXCL2 neutralization inhibited the formation and releasing of neutrophil extracellular traps (NETs) from in vitro cultured primary neutrophils. Furthermore, CXCL2-neutralizing antibody treatment reduced brain infarcts and improved vascular reperfusion at day 3 postischemic stroke. CONCLUSIONS: Collectively, brain border-derived CXCL2+ neutrophil expansion may impair vascular reperfusion by releasing NETs following ischemic stroke.

Unraveling the molecular mechanisms of Ace2-mediated post-COVID-19 cognitive dysfunction through systems genetics approach.

The dysregulation of Angiotensin-converting enzyme 2 (ACE2) in central nervous system is believed associates with COVID-19 induced cognitive dysfunction. However, the detailed mechanism remains largely unknown. In this study, we performed a comprehensive system genetics analysis on hippocampal ACE2 based on BXD mice panel. Expression quantitative trait loci (eQTLs) mapping showed that Ace2 was strongly trans-regulated, and the elevation of Ace2 expression level was significantly correlated with impaired cognitive functions. Further Gene co-expression analysis showed that Ace2 may be correlated with the membrane proteins in Calcium signaling pathway. Further, qRT-PCR confirmed that SARS-CoV-2 spike S1 protein upregulated ACE2 expression together with eight membrane proteins in Calcium Signaling pathway. Moreover, such elevation can be attenuated by recombinant ACE2. Collectively, our findings revealed a potential mechanism of Ace2 in cognitive dysfunction, which could be beneficial for COVID-19-induced cognitive dysfunction prevention and potential treatment.

Regulatory mechanisms orchestrating cellular diversity of Cd36+ olfactory sensory neurons revealed by scRNA-seq and scATAC-seq analysis.

Recent discoveries have revealed remarkable complexity within olfactory sensory neurons (OSNs), including the existence of two OSN populations based on the expression of Cd36. However, the regulatory mechanisms governing this cellular diversity in the same cell type remain elusive. Here, we show the preferential expression of 79 olfactory receptors in Cd36+ OSNs and the anterior projection characteristics of Cd36+ OSNs, indicating the non-randomness of Cd36 expression. The integrated analysis of single-cell RNA sequencing (scRNA-seq) and scATAC-seq reveals that the differences in Cd36+/- OSNs occur at the immature OSN stage, with Mef2a and Hdac9 being important regulators of developmental divergence. We hypothesize that the absence of Hdac9 may affect the activation of Mef2a, leading to the up-regulation of Mef2a target genes, including teashirt zinc finger family member 1 (Tshz1), in the Cd36+ OSN lineage. We validate that Tshz1 directly promotes Cd36 expression through enhancer bindings. Our study unravels the intricate regulatory landscape and principles governing cellular diversity in the olfactory system.

Compromised informed consent due to functional health literacy challenges in Chinese hospitals.

BACKGROUND: Medical informed consent stands as an ethical and legal requisite preceding any medical intervention. Hospitalized patients face functional health literacy (FHL) challenges when dealing with informed consent forms (ICFs). The legitimacy of ICFs and informed consent procedures in China remains substantially undisclosed. The study's aim was to investigate if Chinese patients have adequate FHL to be truly informed before providing medical consent. METHODS: In this cross-sectional, structured interview-based study, FHL was assessed within the context of the informed consent scenarios in two teaching hospitals (a 1500-bed general tertiary hospital and a 700-bed cancer hospital) affiliated with Shantou University Medical College. Twenty-seven patients admitted across clinical departments, along with their relatives (n = 59), were enrolled in the study after obtaining informed consent. The participants underwent a three-step assessment with two selected ICFs -teach-back skills, perceived understanding (perception), and informed knowledge (cognizance), with each component carrying a maximum score of 10. Data were analyzed with SPSS (version 22.0) for descriptive and inferential statistics, with consideration of significant P values as < 0.05. RESULTS: The median age (IQR and range) of participants was 35.5 (28 - 49 and 13 - 74) years. Most participants had only high school education (24.4%, 21/86) or below high school education (47.7%, 41/86). The median score (IQR) of FHL assessments-teach-back, perception, and cognizance-was 4.0 (2.5, 5.8), 8.0 (6.8, 8.8), and 6.5 (5.5, 8.0) out of 10, respectively. A moderate correlation was observed between the scores of cognizance and teach-back (r = 0.359, P = 0.002) or perception (r = 0.437, P < 0.001). Multivariate linear regression analysis predicted being a patient and having lower education levels as independent risk factors of inadequate FHL (Ps = 0.001). Lack of patient-centeredness in ICFs, time constraints, and poor clinical communication were identified as barriers impeding informed consent. CONCLUSIONS: This study demonstrates inadequacy in personal FHL and impaired organizational HL, resulting in compromised informed consent in Chinese teaching hospitals. As a remedy, we propose improving the quality of ICFs and institutionally mandated outcome-focused training on informed consent for all concerned clinicians to enhance medical ethics, ensure quality health care, address patient values, and mitigate potential medical conflicts.

Prenatal chromosomal microarray analysis in a large Chinese cohort of fetuses with congenital heart defects: a single center study.

BACKGROUND AND OBJECTIVES: Congenital heart defect (CHD) is one of the most common birth defects. The aim of this cohort study was to evaluate the prevalence of chromosomal abnormalities and the clinical utility of chromosomal microarray analysis (CMA) in fetuses with different types of CHD, aiming to assist genetic counseling and clinical decision-making. METHODS: In this study, 642 fetuses with CHD were enrolled from a single center over a six-year period (2017-2022). Both conventional karyotyping and CMA were performed simultaneously on these fetuses. RESULTS: The diagnostic yield of CMA in fetuses with CHD in our study was 15.3% (98/642). Our findings revealed a significant increase in the diagnostic yield of CMA compared to karyotyping in fetuses with CHD. Among CHD subgroups, the diagnostic yields were high in complex CHD (34.9%), conotruncal defects (28.6%), right ventricular outflow tract obstructive defects (RVOTO) (25.9%), atrioventricular septal defects (AVSD) (25.0%) and left ventricular outflow tract obstructive defects (LVOTO) (24.1%), while those in other CHD (10.6%) and septal defects (10.9%) were relatively low. The overall detection rate of clinically significant chromosomal abnormalities was significantly higher in the non-isolated CHD group compared to the isolated CHD group (33.1% vs. 9.9%, P < 0.0001). Interestingly, numerical chromosomal abnormalities were more likely to occur in the non-isolated CHD group than in the isolated CHD group (20.3% vs. 2.0%, P < 0.0001). The rate of termination of pregnancy (TOP)/Still birth in the non-isolated CHD group was significantly higher than that in the isolated CHD group (40.5% vs. 20.6%, P < 0.0001). Compared to the isolated CHD group, the detection rate of clinically significant chromosomal abnormalities was significantly higher in the group of CHD with soft markers (35.6% vs. 9.9%, P < 0.0001) and in the group of CHD with additional structural anomalies (36.1% vs. 9.9%, P < 0.0001). CONCLUSIONS: CMA is a reliable and high-resolution technique that should be recommended as the front-line test for prenatal diagnosis of fetuses with CHD. The prevalence of chromosomal abnormalities varies greatly among different subgroups of CHD, and special attention should be given to prenatal non-isolated cases of CHD, especially those accompanied by additional structural anomalies or soft markers.

Development and optimization of a self micro-emulsifying drug delivery system (SMEDDS) for co-administration of sorafenib and curcumin.

In this study, we developed a novel co-administration of curcumin and sorafenib using a Self micro-emulsifying Drug Delivery System (SMEDDS) called Sorafenib-Curcumin Self micro-emulsifying Drug Delivery System (SOR-CUR-SMEDDS). The formulation was optimized using star point design-response surface methodology, and in vitro cellular experiments were conducted to evaluate the delivery ratio and anti-tumor efficacy of the curcumin and sorafenib combination. The SOR-CUR-SMEDDS exhibited a small size distribution of 13.48 ± 0.61 nm, low polydispersity index (PDI) of 0.228 ± 0.05, and negative zeta potential (ZP) of - 12.4 mV. The half maximal inhibitory concentration (IC50) of the SOR-CUR-SMEDDS was 3-fold lower for curcumin and 5-fold lower for sorafenib against HepG2 cells (human hepatocellular carcinoma cells). Transmission electron microscopy (TEM) and particle size detection confirmed that the SOR-CUR-SMEDDS droplets were uniformly round and within the nano-emulsion particle size range of 10-20 nm. The SMEDDS were characterized then studied for drug release in vitro via dialysis membranes. Curcumin was released more completely in the combined delivery system, showing the largest in vitro drug release (79.20%) within 7 days in the medium, while the cumulative release rate of sorafenib in the release medium was low, reaching 58.96% on the 7 day. In vitro pharmacokinetic study, it demonstrated a significant increase in oral bioavailability of sorafenib (1239.88-fold) and curcumin (3.64-fold) when administered in the SMEDDS. These findings suggest that the SMEDDS formulation can greatly enhance drug solubility, improve drug absorption and prolong circulation in vivo, leading to increased oral bioavailability of sorafenib and curcumin.

Clinical and genetic analysis of children with glucose transporter type 1 deficiency syndrome.

Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is a rare metabolic encephalopathy with a wide variety of clinical phenotypes. In the present study, 15 patients diagnosed with GLUT1-DS were selected, all of whom had obvious clinical manifestations and complete genetic testing. Their clinical data and genetic reports were collated. All patients were provided with a ketogenic diet (KD) and an improvement in their symptoms was observed during a follow-up period of up to 1 year. The results revealed that the 15 cases had clinical symptoms, such as convulsions or dyskinesia. Although none had a cerebrospinal fluid/glucose ratio <0.4, the genetic report revealed that all had the solute carrier family 2 member 1 gene variant, and their clinical symptoms basically improved following the use of the KD. GLUT1-DS is a genetic metabolic disease that causes a series of neurological symptoms due to glucose metabolism disorders in the brain. Low glucose levels in cerebrospinal fluid and genetic testing are key diagnostic criteria, and the KD is a highly effective treatment option. By summarizing and analyzing patients with GLUT1-DS, summarizing clinical characteristics and expanding their gene profile, the findings of the present study may be of clinical significance for the early recognition and diagnosis of the disease, so as to conduct early treatment and shorten the duration of brain energy deficiency. This is of utmost importance for improving the prognosis and quality of life of affected children.

Targeting cuproptosis for cancer therapy: mechanistic insights and clinical perspectives.

Cuproptosis is a newly identified form of cell death induced by excessive copper (Cu) accumulation within cells. Mechanistically, cuproptosis results from Cu-induced aggregation of dihydrolipoamide S-acetyltransferase, correlated with the mitochondrial tricarboxylic acid cycle and the loss of iron-sulfur cluster proteins, ultimately resulting in proteotoxic stress and triggering cell death. Recently, cuproptosis has garnered significant interest in tumor research due to its potential as a crucial therapeutic strategy against cancer. In this review, we summarized the cellular and molecular mechanisms of cuproptosis and its relationship with other types of cell death. Additionally, we reviewed the current drugs or strategies available to induce cuproptosis in tumor cells, including Cu ionophores, small compounds, and nanomedicine. Furthermore, we targeted cell metabolism and specific regulatory genes in cancer therapy to enhance tumor sensitivity to cuproptosis. Finally, we discussed the feasibility of targeting cuproptosis to overcome tumor chemotherapy and immunotherapy resistance and suggested future research directions. This study suggested that targeting cuproptosis could open new avenues for developing tumor therapy.

PM10 exposure induces bronchial hyperresponsiveness by upreguating acetylcholine muscarinic 3 receptor.

Exposure to particulate matter (PM10) can induce respiratory diseases that are closely related to bronchial hyperresponsiveness. However, the involved mechanism remains to be fully elucidated. This study aimed to demonstrate the effects of PM10 on the acetylcholine muscarinic 3 receptor (CHRM3) expression and the role of the ERK1/2 pathway in rat bronchial smooth muscle. A whole-body PM10 exposure system was used to stimulate bronchial hyperresponsiveness in rats for 2 and 4 months, accompanied by MEK1/2 inhibitor U0126 injection. The whole-body plethysmography system and myography were used to detect the pulmonary and bronchoconstrictor function, respectively. The mRNA and protein levels were determined by Western blotting, qPCR, and immunofluorescence. Enzyme-linked immunosorbent assay was used to detect the inflammatory cytokines. Compared with the filtered air group, 4 months of PM10 exposure significantly increased CHRM3-mediated pulmonary function and bronchial constriction, elevated CHRM3 mRNA and protein expression levels on bronchial smooth muscle, then induced bronchial hyperreactivity. Additionally, 4 months of PM10 exposure caused an increase in ERK1/2 phosphorylation and increased the secretion of inflammatory factors in bronchoalveolar lavage fluid. Treatment with the MEK1/2 inhibitor, U0126 inhibited the PM10 exposure-induced phosphorylation of the ERK1/2 pathway, thereby reducing the PM10 exposure-induced upregulation of CHRM3 in bronchial smooth muscle and CHRM3-mediated bronchoconstriction. U0126 could rescue PM10 exposure-induced pathological changes in the bronchus. In conclusion, PM10 exposure can induce bronchial hyperresponsiveness in rats by upregulating CHRM3, and the ERK1/2 pathway may be involved in this process. These findings could reveal a potential therapeutic target for air pollution induced respiratory diseases.

A Bifunctional Methyltransferase in Biosynthesis of Antitumor Antibiotic Streptonigrin.

Streptonigrin (STN, 1) is a highly functionalized aminoquinone alkaloid antibiotic with broad and potent antitumor activity. STN structurally contains four methyl groups belonging to two types: C-methyl group and O-methyl groups. Here, we report the biochemical characterization of the O-methyltransferase StnQ2 that can catalyze both the methylation of a hydroxyl group and a carboxyl group in the biosynthesis of streptonigrin. This work not only provides a new insight into methyltransferases, but also advances the elucidation of the complete biosynthetic pathway of streptonigrin.

Evaluation of Fatigue Behavior of Asphalt Field Cores Using Discrete Element Modeling.

Fatigue cracking is one of the primary distresses of asphalt pavements, which significantly affects the asphalt pavement performance. The fatigue behavior of the asphalt mixture observed in the laboratory test can vary depending on the type of fatigue test and the dimension and shape of the test specimen. The variations can make it difficult to accurately evaluate the fatigue properties of the field asphalt concrete. Accordingly, this study proposed a reliable method to evaluate the fatigue behavior of the asphalt field cores based on discrete element modeling (DEM). The mesoscopic geometric model was built using discrete element software PFC (Particle Flow Code) and CT scan images of the asphalt field cores. The virtual fatigue test was simulated in accordance with the semi-circular bending (SCB) test. The mesoscopic parameters of the contacting model in the virtual test were determined through the uniaxial compression dynamic modulus test and SCB test. Based on the virtual SCB test, the displacement, contact forces, and crack growth were analyzed. The test results show that the fatigue life simulated in the virtual test was consistent with that of the SCB fatigue test. The fatigue cracks in the asphalt mixture were observed in three stages, i.e., crack initiation, crack propagation, and failure. It was found that the crack propagation stage consumes a significant portion of the fatigue life since the tensile contact forces mainly increase in this stage.

Experimental Investigation of Water Vapor Concentration on Fracture Properties of Asphalt Concrete.

The effect of moisture on the fracture resistance of asphalt concrete is a significant concern in pavement engineering. To investigate the effect of the water vapor concentration on the fracture properties of asphalt concrete, this study first designed a humidity conditioning program at the relative humidity (RH) levels of 2%, 50%, 80%, and 100% for the three types of asphalt concrete mixtures (AC-13C, AC-20C, and AC-25C).The finite element model was developed to simulate the water vapor diffusion and determine the duration of the conditioning period. The semi-circular bending (SCB) test was then performed at varying temperatures of 5 °C, 15 °C, and 25 °C to evaluate the fracture energy and tensile strength of the humidity-conditioned specimens. The test results showed that the increasing temperature and the RH levels resulted in a lower peak load but greater displacement of the mixtures. Both the fracture energy and tensile strength tended to diminish with the rising temperature. It was also found that moisture had a significant effect on the tensile strength and fracture energy of asphalt concrete. Specifically, as the RH level increased from 2% to 100% (i.e., the water vapor concentration rose from 0.35 g/m3 to 17.27 g/m3), the tensile strength of the three types of mixtures was reduced by 34.84% on average, which revealed that the water vapor led to the loss of adhesion and cohesion within the mixture. The genetic expression programming (GEP) model was developed to quantify the effect of water vapor concentrations and temperature on the fracture indices.