Ultrasonic-assisted extraction, anti-biofilm activity, and mechanism of action of Ku Shen (Sophorae Flavescentis Radix) extracts against Vibrio parahaemolyticus.

The objective of this study is to optimize the ultrasonic-assisted extraction process of Ku Shen (Sophorae Flavescentis Radix) extracts (KSE) against Vibrio parahaemolyticus and explore their anti-biofilm activity and mechanism of action. The ultrasonic-assisted extraction process of KSE optimized by single factor experiment, Box-Behnken design and response surface methodology was as follows: 93% ethanol as solvent, liquid/material ratio of 30 mL/g, ultrasonic power of 500 W, extraction temperature of 80°C and time of 30 min. Under these conditions, the diameter of inhibition circle of KSE was 15.60 ± 0.17 mm, which had no significant difference with the predicted value. The yield of dried KSE is 32.32 ± 0.57% and the content of total flavonoids in KSE was 57.02 ± 5.54%. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of KSE against V. parahaemolyticus were 0.25 and 0.5 mg/mL, respectively. Crystal violet staining, Congo red plate, spectrophotometry, CCK-8 and scanning electron microscopy were used to investigate the activity and mechanism of action of KSE against V. parahaemolyticus biofilm. The results showed that the sub-MIC of KSE could significantly inhibit biofilm formation, reduce the synthesis of polysaccharide intercellular adhesin (PIA) and the secretion of extracellular DNA. In addition, the inhibition rate of biofilm formation and clearance rate of mature biofilm of 1.0 mg/mL KSE were 85.32 and 74.04%, and the reduction rate of metabolic activity of developing and mature biofilm were 77.98 and 74.46%, respectively. These results were confirmed by visual images obtained by scanning electron microscopy. Therefore, KSE has the potential to further isolate the anti-biofilm agent and evaluate it for the preservation process of aquatic products.

Low-Toxicity and High-Efficiency Streptomyces Genome Editing Tool Based on the Miniature Type V-F CRISPR/Cas Nuclease AsCas12f1.

Genome editing tools based on SpCas9 and FnCpf1 have facilitated strain improvements for natural product production and novel drug discovery in Streptomyces. However, due to high toxicity, their editing requires high DNA transformation efficiency, which is unavailable in most streptomycetes. The transformation efficiency of an all-in-one editing tool based on miniature Cas nuclease AsCas12f1 was significantly higher than those of SpCas9 and FnCpf1 in tested streptomycetes, which is due to its small size and weak DNA cleavage activity. Using this tool, in Streptomyces coelicolor, we achieved 100% efficiency for single gene or gene cluster deletion and 46.7 and 40% efficiency for simultaneous deletion of two genes and two gene clusters, respectively. AsCas12f1 was successfully extended to Streptomyces hygroscopicus SIPI-054 for efficient genome editing, in which SpCas9/FnCpf1 does not work well. Collectively, this work offers a low-toxicity, high-efficiency genome editing tool for streptomycetes, particularly those with low DNA transformation efficiency.

Unveiling the role of hypoxic macrophage-derived exosomes in driving colorectal cancer progression.

The crosstalk between tumor cells and macrophages under hypoxic conditions has been acknowledged as a pivotal determinant in the progression of colorectal cancer (CRC). Previous research has underscored the significance of exosomes derived from hypoxic tumor cells in facilitating tumor progression through inducing the polarization of macrophages towards the M2-like phenotype. The precise influence of hypoxic macrophage-derived exosomes (HMDEs) on the progression of CRC has not yet been fully elucidated. The objective of this study was to investigate the role of HMDEs in the progression of CRC. We discovered that there was an elevated release of exosomes derived from macrophages in hypoxic conditions. Additionally, the hypoxia-induced macrophage-derived exosomes played a crucial role in promoting the progression of CRC. We have also demonstrated that HMDEs have the ability to induce cell cycle transition and inhibit cell apoptosis, thereby promoting the growth of CRC cells. Furthermore, the underlying molecular mechanisms of these effects have been identified. The overexpression of Hif-1α results in its direct interaction with distinct regions (-521- -516 bp and -401- -391 bp) of the Hsp90 promoter during hypoxic circumstances. This binding event led to the overexpression of Hsp90 and the subsequent elevation of Hsp90 protein levels within HMDEs. Importantly, the crucial interaction between Hsp90 and Lats1 resulted in the deactivation of Lats1 and the inhibition of Yap phosphorylation. Ultimately, this series of events lead to the deactivation of the Hippo signaling pathway. Our in vivo and in vitro studies presented compelling evidence for the crucial role of hypoxic macrophage-derived exosomal Hsp90 in promoting CRC progression through the inhibition of the Hippo signaling pathway. These findings represented a significant advancement in our comprehension of the complex interplay between macrophages and CRC cells under hypoxic conditions.

GPCR signaling contributes to immune characteristics of microenvironment and process of EBV-induced lymphomagenesis.

Epstein-Barr virus (EBV) is the oncogenic driver of multiple cancers. However, the underlying mechanism of virus-cancer immunological interaction during disease pathogenesis remains largely elusive. Here we reported the first comprehensive proteogenomic characterization of natural killer/T-cell lymphoma (NKTCL), a representative disease model to study EBV-induced lymphomagenesis, incorporating genomic, transcriptomic, and in-depth proteomic data. Our multi-omics analysis of NKTCL revealed that EBV gene pattern correlated with immune-related oncogenic signaling. Single-cell transcriptome further delineated the tumor microenvironment as immune-inflamed, -deficient, and -desert phenotypes, in association with different setpoints of cancer-immunity cycle. EBV interacted with transcriptional factors to provoke GPCR interactome (GPCRome) reprogramming. Enhanced expression of chemokine receptor-1 (CCR1) on malignant and immunosuppressive cells modulated virus-cancer interaction on microenvironment. Therapeutic targeting CCR1 showed promising efficacy with EBV eradication, T-cell activation, and lymphoma cell killing in NKTCL organoid. Collectively, our study identified a previously unknown GPCR-mediated malignant progression and translated sensors of viral molecules into EBV-specific anti-cancer therapeutics.

Enhanced Thermal Shock Resistance of High-Temperature Organic Adhesive by CF-SiCNWs Binary Phase Structure.

The development of high-temperature organic adhesive for bonding ultra-high-temperature ceramics with excellent thermal shock resistance has important significance to thermal protection systems for high-temperature environment application. In this study, high-temperature organic adhesive (HTOA) with carbon-fiber-SiC nanowires (CF-SiCNWs) binary phase enhancement structure was prepared. The method is that the SiCNWs grow on the chopped carbon-fiber surface and in the matrix of modified HTOA during high-temperature heat treatment with the help of a catalyst by a tip-growth way and with a vapor-liquid-solid (V-L-S) growth pattern. The results showed that the CF-SiCNWs binary phase enhancement structure plays a significant role in improving thermal shock resistance of high-temperature organic adhesive. The retention rate of the joint bond strength for the bonding samples after 20 cycles of thermal shock testing reaches 39.19%, which is higher than for the ones without CF, whose retain rate is only 6.78%. The shear strength of the samples with the CF-SiCNWs binary phase enhancement structure was about 10% higher than for those without the enhancement structure after 20 cycles of thermal shock.

Development of a CRISPR/Cas9D10A Nickase (nCas9)-Mediated Genome Editing Tool in Streptomyces.

Streptomycetes have a strong ability to produce a vast array of bioactive natural products (NPs) widely used in agriculture and veterinary/human medicine. The recently developed CRISPR/Cas9-based genome editing tools have greatly facilitated strain improvement for target NP overproduction as well as novel NP discovery in Streptomyces. However, CRISPR/Cas9 shows high toxicity to the host, limiting its application in many Streptomyces strains with a low DNA transformation efficiency. In this study, we developed a low-toxicity CRISPR/Cas9D10A nickase (nCas9)-based genome editing tool in the model strain Streptomyces coelicolor M145. We showed that in the presence of both targeting sgRNA and Cas proteins, utilization of nCas9 instead of Cas9 significantly reduced the toxicity to the host and greatly enhanced cell survival. Using this tool, we achieved deletion of single genes and gene clusters with efficiencies of 87-100 and 63-87%, and simultaneous deletion of two genes or gene clusters with efficiencies of 47 and 43%, respectively. The editing efficiency of nCas9 is comparable to that of the Cas9-mediated editing tool. Finally, the nCas9-based editing tool was successfully applied for genome editing in the industrial rapamycin-producing strain Streptomyces rapamycinicus, in which CRISPR/Cas9 cannot work well. We achieved the deletion of three tested genes with an efficiency of 27.2-30%. Collectively, the CRISPR/nCas9-based editing tool offers a convenient and efficient genetic modification system for the engineering of streptomycetes, particularly those with low DNA transformation efficiency.

Long-term, real-time and label-free live cell image processing and analysis based on a combined algorithm of CellPose and watershed segmentation.

Developing a rapid and quantitative method to accurately evaluate the physiological abilities of living cells is critical for tumor control. Many experiments have been conducted in the field of biology in an attempt to measure the proliferation and movement abilities of cells, but existing methods cannot provide real-time and objective data for label-free cells. The quantitative imaging technique, including an automatic segmentation algorithm for individual label-free cells, has been a breakthrough in this regard. In this study, we develop a combined automatic image processing algorithm of CellPose and watershed segmentation for the long-term and real-time imaging of label-free cells. This method shows strong reliability in cell identification regardless of cell densities, allowing us to obtain accurate information about the number and proliferation ability of the target cells. Additionally, our results also suggest that this method is a reliable way to assess real-time data on drug cytotoxicity, cell morphology, and cell movement ability.

EGR1 functions as a new host restriction factor for SARS-CoV-2 to inhibit virus replication through the E3 ubiquitin ligase MARCH8.

IMPORTANCE: Emerging vaccine-breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants highlight an urgent need for novel antiviral therapies. Understanding the pathogenesis of coronaviruses is critical for developing antiviral drugs. Here, we demonstrate that the SARS-CoV-2 N protein suppresses interferon (IFN) responses by reducing early growth response gene-1 (EGR1) expression. The overexpression of EGR1 inhibits SARS-CoV-2 replication by promoting IFN-regulated antiviral protein expression, which interacts with and degrades SARS-CoV-2 N protein via the E3 ubiquitin ligase MARCH8 and the cargo receptor NDP52. The MARCH8 mutants without ubiquitin ligase activity are no longer able to degrade SARS-CoV-2 N proteins, indicating that MARCH8 degrades SARS-CoV-2 N proteins dependent on its ubiquitin ligase activity. This study found a novel immune evasion mechanism of SARS-CoV-2 utilized by the N protein, which is helpful for understanding the pathogenesis of SARS-CoV-2 and guiding the design of new prevention strategies against the emerging coronaviruses.

Ring Stripping, Ring Cutting, and Growth Regulators Promote Phase Change and Early Flowering in Pear Seedlings.

Hybrid breeding is the most important means of selecting pear (Pyrus) varieties, but a long juvenile period severely restricts the selection of new varieties. In this study, we used 'Yuluxiang' × 'Akituki' 4-year-old seedling trees to study the effects of plant growth regulators, ring stripping, and ring cutting on the promotion of phase change and flowering to assist in shortening the breeding cycle. A single application of 100 mg/kg 6-BA + 1000 mg/kg PP333 was most effective in promoting phase change and flowering. This treatment effectively inhibited the growth and thickening of annual shoots, significantly increased soluble sugar and protein contents in buds, increased the ABA content by 45.41%, decreased the IAA content by 7.35%, increased the expression of the flower-promoting genes FT and LFY by 2273.41% and 1153.71%, respectively, and decreased the expression of the flower-suppressing gene TFL1 by 74.92%. The flowering plant rate increased by 23.34% compared to the control. Both ring stripping and ring cutting were effective in promoting phase change and flowering, significantly increasing the flowering rate, inflorescence number, and the number of flowering plants. For improving the flowering rate, the ring-stripping treatment had the strongest effect and effectively inhibited the growth and thickening of annual shoots, while also significantly increasing the soluble sugar and protein contents in buds, reducing the contents of IAA and GA3 by 8.73% and 50.12%, respectively, increasing the expression of FT and LFY by 80.01% and 821.14%, respectively, and reducing the expression of the flower-suppressing gene TFL1 by 59.22%. In conclusion, ring stripping, ring cutting, and spraying of 100 mg/kg 6-BA + 1000 mg/kg PP333 were effective in promoting phase change and early flowering in seedling trees.

Quantitative and qualitative condylar changes following stabilization splint therapy in patients with temporomandibular joint disorders.

OBJECTIVE: This study aimed to explore the quantitative and qualitative condylar changes following stabilization splint (S.S) therapy, including condylar position, morphology, and bone mineral density (BMD) in subjects with temporomandibular disorders (TMD). MATERIALS AND METHODS: In this retrospective clinical study, we enrolled 40 TMD subjects (80 joints) aged 18 to 35 years, for whom a S.S was used to treat TMD. The 80 TMD consists of 32 masticatory muscle disorders (myalgia) and 48 TMJ disorders (arthralgia). Cone beam computed tomography (CBCT) was used to scan the TMJs of subjects pre- and post-treatment for three-dimensional analysis (3D). Using Mimics software v.21.0, quantitative (3D condylar and joint spaces dimensions parameters were measured using linear measurements in millimeters, according to the Kamelchuk method and Ikeda method, while the assessment of anteroposterior condyle position within the glenoid fossa was based on the method of Pullinger and Hollender), and qualitative (a round bone tissue with an area of 2 mm2 in three representative areas according to the Kamelchuk method to measure condylar BMD) pre- and post-treatment. Intra- and inter-group statistical comparisons were performed using the Wilcoxon signed ranks and the Kruskal-Wallis test, respectively. RESULTS: The course of treatment was 6-12 months, with an average of 9.1 months. For the pre- and post-treatment quantitative comparisons, there was a statistically significant difference in the anterior joint space (AJS) and coronal medial space, as well as the condyle length in the myalgia group and condylar width in the arthralgia group. For qualitative measurements, a significant difference was observed in the posterior slope of the myalgia group and the arthralgia group's anterior, superior, and posterior slopes. The inter-group comparisons revealed significant differences in AJS, condylar length, and anterior slope density. CONCLUSION: In short-term follow-up, the S.S influenced patients with TMD from different origins; it changes anterior and coronal medial joint space, condyle length in myalgia, and width in arthralgia. Furthermore, it improved the condyle bone density more evidently in arthralgia. CLINICAL RELEVANCE: This study highlights the influence of S.S on symptomatic populations with TMD of different origins from a qualitative and quantitative perspective.

A nuclear NKRF interacting long noncoding RNA controls EBV eradication and suppresses tumor progression in natural killer/T-cell lymphoma.

Long intergenic noncoding RNAs (lincRNAs) are differentially expressed in EBV-infected cells and play an essential role in tumor progression. Molecular pathogenesis of lincRNAs in EBV-driven natural killer T cell lymphoma (NKTCL) remains unclear. Here we investigated the ncRNA profile using high-throughput RNA sequencing data of 439 lymphoma samples and screened out LINC00486, whose downregulation was further validated by quantitative real-time polymerase chain reaction in EBV-encoded RNA (EBER)-positive lymphoma, particularly NKTCL. Both in vitro and in vivo studies revealed the tumor suppressive function of LINC00486 through inhibiting tumor cell growth and inducing G0/G1 cell cycle arrest. As mechanism of action, LINC00486 specifically interacted with NKRF to abrogate its binding with phosphorylated p65, activated NF-κB/TNF-α signaling and subsequently enhanced EBV eradication. Solute carrier family 1 member 1 (SLC1A1), upregulated and mediated the glutamine-addiction and tumor progression in NKTCL, was negatively correlated with the expression of NKRF. NKRF specifically bound to the promoter and transcriptionally downregulated the expression of SLC1A1, as evidenced by Chromatin Immunoprecipitation (ChIP) and luciferase assay. Collectively, LINC00486 functioned as a tumor suppressor and counteracted EBV infection in NKTCL. Our study improved the knowledge of EBV-driven oncogenesis in NKTCL and provided the clinical rationale of EBV eradication in anti-cancer treatment.

Optimized Extraction, Identification and Anti-Biofilm Action of Wu Wei Zi (Fructus Schisandrae Chinensis) Extracts against Vibrio parahaemolyticus.

The pathogenicity of foodborne Vibrio parahaemolyticus is a major concern for global public health. This study aimed to optimize the liquid-solid extraction of Wu Wei Zi extracts (WWZE) against Vibrio parahaemolyticus, identify its main components, and investigate the anti-biofilm action. The extraction conditions optimized by the single-factor test and response surface methodology were ethanol concentration of 69%, temperature at 91 °C, time of 143 min, and liquid-solid ratio of 20:1 mL/g. After high performance liquid chromatography (HPLC) analysis, it was found that the main active ingredients of WWZE were schisandrol A, schisandrol B, schisantherin A, schisanhenol, and schisandrin A-C. The minimum inhibitory concentration (MIC) of WWZE, schisantherin A, and schisandrol B measured by broth microdilution assay was 1.25, 0.625, and 1.25 mg/mL, respectively, while the MIC of the other five compounds was higher than 2.5 mg/mL, indicating that schisantherin A and schizandrol B were the main antibacterial components of WWZE. Crystal violet, Coomassie brilliant blue, Congo red plate, spectrophotometry, and Cell Counting Kit-8 (CCK-8) assays were used to evaluate the effect of WWZE on the biofilm of V. parahaemolyticus. The results showed that WWZE could exert its dose-dependent potential to effectively inhibit the formation of V. parahaemolyticus biofilm and clear mature biofilm by significantly destroying the cell membrane integrity of V. parahaemolyticus, inhibiting the synthesis of intercellular polysaccharide adhesin (PIA), extracellular DNA secretion, and reducing the metabolic activity of biofilm. This study reported for the first time the favorable anti-biofilm effect of WWZE against V. parahaemolyticus, which provides a basis for deepening the application of WWZE in the preservation of aquatic products.

Flavivirus prM interacts with MDA5 and MAVS to inhibit RLR antiviral signaling.

BACKGROUND: Vector-borne flaviviruses, including tick-borne encephalitis virus (TBEV), Zika virus (ZIKV), West Nile virus (WNV), yellow fever virus (YFV), dengue virus (DENV), and Japanese encephalitis virus (JEV), pose a growing threat to public health worldwide, and have evolved complex mechanisms to overcome host antiviral innate immunity. However, the underlying mechanisms of flavivirus structural proteins to evade host immune response remain elusive. RESULTS: We showed that TBEV structural protein, pre-membrane (prM) protein, could inhibit type I interferon (IFN-I) production. Mechanically, TBEV prM interacted with both MDA5 and MAVS and interfered with the formation of MDA5-MAVS complex, thereby impeding the nuclear translocation and dimerization of IRF3 to inhibit RLR antiviral signaling. ZIKV and WNV prM was also demonstrated to interact with both MDA5 and MAVS, while dengue virus serotype 2 (DENV2) and YFV prM associated only with MDA5 or MAVS to suppress IFN-I production. In contrast, JEV prM could not suppress IFN-I production. Overexpression of TBEV and ZIKV prM significantly promoted the replication of TBEV and Sendai virus. CONCLUSION: Our findings reveal the immune evasion mechanisms of flavivirus prM, which may contribute to understanding flavivirus pathogenicity, therapeutic intervention and vaccine development.

Euclidean distance-based Raman spectroscopy (EDRS) for the prognosis analysis of gastric cancer: A solution to tumor heterogeneity.

The prognosis analysis of gastric cancer is critical for selection of treatments and development of advanced therapeutic methods. A prognosis approach that is accurate, fast, convenient, and of low cost for gastric cancers is in high demand. Raman spectroscopy is a label-free and non-destructive technique to provide molecular fingerprints of biological samples, holding promises for cancer prognosis. However, the major challenge of gastric cancer prognosis lies in the widely existing tumor heterogeneity, which leads to unexpected spectral variations within one type of samples. In this work, we have developed the Euclidean distance (ED)-based Raman spectroscopy (EDRS) method for the prognosis analysis of gastric cancer to eliminate the influence of tumor heterogeneity. Raman spectra were first collected on the slices of paraffin-preserved tumor tissues from gastric cancer patients. A standard spectrum to represent the 'worst prognostic tumor cells' was then established. The similarity between each spectrum of tissues and the standard spectrum was assessed by ED, to provide a direct assessment on the prognosis status. We have successfully classified the patients into poor and favorable prognosis groups, either based on the averaged regional ED values (sensitivity of 75 %, specificity of 96.8 %), or based on the minimal ED values at the patient level (sensitivity of 90 %, specificity of 100 %). EDRS was also investigated for survival analysis (AUC = 0.955), much better than the commonly applied post-neoadjuvant therapy (ypTNM) category (AUC = 0.718). Our work highlights EDRS as a rapid, accurate, low-cost and robust tool for heterogeneous cancer-related prognosis assessment and survival prediction, providing new insights for spectroscopic tumor analysis.

[Application regularity and solution strategies of mineral medicine Cinnabaris in pediatric preparations].

Mineral medicine is a characteristic element of advantage of traditional Chinese medicine(TCM), which embodies unique scientific connotation. Cinnabaris is a characteristic drug in Chinese medicinal preparations, especially in Chinese medicinal pediatric preparations. Because of the adverse reactions caused by mercury contained, the safety and application of Cinnabaris have attracted much attention. To explore the application regularity and the value of the pediatric preparations containing Cinnabaris, this study statistically analyzed 32 Cinnabaris-contained pediatric preparations in the 2020 edition of the Chinese Pharmacopoeia and 105 pediatric preparations containing Cinnabaris in the Dictionary of Traditional Chinese Medicine Prescriptions(Vol. Ⅰ and Ⅱ). The statistical results indicated that the pediatric preparations and formulae containing Cinnabaris had great advantages in the treatment of pediatric convulsions, but there were still problems in dosage form, dosage, and quality control. In this study, ICP-MS and LC-AFS were further used to determine the content of total mercury and soluble mercury in 15 commercially available pediatric preparations containing Cinnabaris. It was found that the total mercury content was far higher than soluble mercury content in the sample preparations, and there was no obvious correlation between them. According to the results, the research and application strategies of Cinnabaris were put forward in order to provide references for the rational application of Cinnabaris in pediatric preparations.

Analysis of ceRNA networks during mechanical tension-induced osteogenic differentiation of periodontal ligament stem cells.

The molecular mechanisms underlying osteogenic differentiation of periodontal ligament stem cells (PDLSCs) under mechanical tension remain unclear. This study aimed to identify a potential long non-coding ribonucleic acids (lncRNAs)/circular RNAs (circRNAs)-microRNAs (miRNAs)-messenger RNAs (mRNAs) network in mechanical tension-induced osteogenic differentiation of PDLSCs. PDLSCs were isolated from the healthy human periodontal ligament, identified, cultured, and exposed to tensile force. The expression of osteogenic markers was examined, and whole transcriptome sequencing was performed to identify the expression patterns of lncRNA, circRNA, miRNAs, and mRNAs. Enrichment analyses were also performed. Candidate targets of differentially expressed non-coding RNAs (ncRNAs) were predicted, and potential competitive endogenous RNA (ceRNA) networks were constructed by Cytoscape. We found that the osteogenic differentiation of PDLSCs was significantly enhanced under dynamic tension (magnitude: 12%, frequency: 0.7 Hz). Overall, 344 lncRNAs, 57 miRNAs, 41 circRNAs, and 70 mRNAs were differentially expressed in the tension group and the control group. Functional enrichment analysis showed that differentially expressed mRNAs were mainly enriched in osteogenesis-related and mechanical stress-related biological processes and signal transduction pathways (e.g., tumor necrosis factor [TNF] and Hippo signaling pathways). The lncRNA/circRNA-miRNA-mRNA networks were depicted, and potential key ceRNA networks were identified. Our findings may help to further explore the underlying regulatory mechanism of osteogenic differentiation of PDLSCs under mechanical tensile stress.

Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region.

The synergistic response of urban atmospheric aerosols and ozone (O3) to reduction of anthropogenic emissions is complicated and still needs further study. Thus, the changes in physical and chemical properties of urban atmospheric aerosols and O3 during the Coronavirus Disease 2019 (COVID-19) lockdown were investigated at three urban sites and one rural site in Lanzhou with semi-arid climate. Fine particulate matter (PM2.5) decreased at four sites by âˆ¼ 20% while O3 increased by >100% at two urban sites during the COVID-19 lockdown. Both primary emissions and secondary formation of PM2.5 decreased during the lockdown. Significant increase in both sulfur and nitrogen oxidation ratios was found in the afternoon, which accounted for 48.7% of the total sulfate and 40.4% of the total nitrate, respectively. The positive matrix factorization source apportionment revealed increased contribution of secondary formation and decreased contribution of vehicle emissions. Aerosol scattering and absorption decreased by 33.6% and 45.3%, resulting in an increase in visibility by 30% and single scattering albedo (SSA) at 520 nm slightly increased by 0.02. The enhanced O3 production was explained by increased volatile organic compounds to nitrogen oxides ratio, decreased aerosol, as well as increased SSA. The primary emissions of secondary aerosol precursors significantly decreased while Ox (i.e., NO2 and O3) exhibited little change. Consequently, Ox to CO ratio, PM2.5 to elemental carbon (EC) ratio, secondary inorganic aerosols to EC ratio, and secondary organic carbon to EC ratio increased, confirming enhanced secondary aerosol production efficiency during the lockdown. Positive feedback among O3 concentration, secondary aerosol formation, and SSA was revealed to further promote O3 production and secondary aerosol formation. These results provide scientific guidance for collaborative management of O3 and particulate matter pollution for cities with semi-arid climate.