Low-intensity ultrasound-assisted adaptive laboratory evolution of Bacillus velezensis for enhanced production of peptides.

This work aimed to explore low-intensity ultrasound-assisted adaptive laboratory evolution (US-ALE) of Bacillus velezensis and fermentation performance of mutant strains were investigated by nitrogen transformation metabolism. Results showed ultrasound accelerated the process of adaptive evolution and enhanced cell dry weight, amylase and protease activity of mutant strains, accompanied with the improved transformation abilities of NO-3-N to NH4+-N. Compared with original strain, the total peptide-N, peptide-N (<3 kDa) and autolytic peptide-N of mutant strains increased by the maximum 23.17%, 66.07% and 30.30%, respectively, based on ideal fermentation medium. According to the actual liquid-state fermentation of soybean meal and corn gluten meal with mutant strains, the highest peptide yields of 50.63% and 23.67% were noticed in mutant strain US-ALE-BV3, accompanied with the improved amino acid composition by bacterial autolysis technology. Thus, this study showed that low-intensity ultrasound could accelerate the process of adaptive evolution and US-ALE will provide more possibilities for modifying fermentation strains.

Development and atomic structure of a new fluorescence-based sensor to probe heme transfer in bacterial pathogens.

Heme is the most abundant source of iron in the human body and is actively scavenged by bacterial pathogens during infections. Corynebacterium diphtheriae and other species of actinobacteria scavenge heme using cell wall associated and secreted proteins that contain Conserved Region (CR) domains. Here we report the development of a fluorescent sensor to measure heme transfer from the C-terminal CR domain within the HtaA protein (CR2) to other hemoproteins within the heme-uptake system. The sensor contains the CR2 domain inserted into the ß2 to ß3 turn of the Enhanced Green Fluorescent Protein (EGFP). A 2.45 Å crystal structure reveals the basis of heme binding to the CR2 domain via iron-tyrosyl coordination and shares conserved structural features with CR domains present in Corynebacterium glutamicum. The structure and small angle X-ray scattering experiments are consistent with the sensor adopting a V-shaped structure that exhibits only small fluctuations in inter-domain positioning. We demonstrate heme transfer from the sensor to the CR domains located within the HtaA or HtaB proteins in the heme-uptake system as measured by a âˆ¼ 60% increase in sensor fluorescence and native mass spectrometry.

Ultrasound-assisted enzyme extraction and properties of Shatian pomelo peel polysaccharide.

In this study, Shatian pomelo peel was used as the raw material for extracting polysaccharides using hot water extraction (HW) and ultrasonic-assisted enzyme (UVE) methods, respectively. The optimal parameters for extractingShatian pomelo peel polysaccharides (StPP) using the ultrasound-assisted enzymatic method were determined using response surface methodology (RSM). The optimal conditions for the extraction of StPP were as follows: ultrasound power 350 W, ultrasound time 50 min, enzymatic digestion time 50 min, compound enzyme addition 1.5%, and enzymatic digestion temperature 55 °C. The yield of StPP was found to be 30.1310% under these conditions. Comparing the physicochemical properties and antioxidant activity of StPP extracted using different methods, it was observed that ultrasound-assisted enzyme extraction resulted in higher yield, sugar content and glucuronic acid content of StPP compared to traditional hot water extraction. Additionally, StPP extracted by ultrasound-assisted enzyme extraction showed better antioxidant activity. These results suggest that ultrasound-assisted enzymatic extraction is an effective method to enhance the activity of natural polysaccharides.

Ubiquitin specific peptidase 47 contributes to liver regeneration.

AIMS: Hepatocytes resume proliferation following liver injuries to compensate for the loss of liver mass. Robust liver regeneration is an intrinsic and pivotal process that facilitates restoration of liver anatomy and function. In the present study we investigated the role of ubiquitin-specific peptidase 47 (USP47) in liver regeneration. METHODS AND MATERIALS: Proliferation of hepatocytes was evaluated by Ki67 staining in vivo and EdU incorporation in vitro. DNA-protein interaction was evaluated by chromatin immunoprecipitation (ChIP). RESULTS: USP47 expression was up-regulated in hepatocytes isolated from mice subjected to partial hepatectomy (PHx) or exposed to HGF treatment. Ingenuity pathway analysis revealed E2F1 as a primary regulator of USP47 transcription. Reporter assay and ChIP assay confirmed that E2F1 directly bound to the USP47 promoter and activated USP47 transcription. Consistently, E2F1 knockdown abrogated USP47 induction by HGF. Compared to the wild type littermates, USP47 knockout mice displayed compromised liver regeneration following PHx. In addition, USP47 inhibition by a small-molecule compound impaired liver regeneration in mice. On the contrary, USP47 over-expression enhanced proliferation of hepatocytes in vitro and promoted liver regeneration in mice. Importantly, a positive correlation between USP47 expression and hepatocyte proliferation was identified in patients with acute liver failure (ALF). SIGNIFICANCE: Our data suggest that USP47, transcriptionally activated by E2F1, plays an essential role in liver regeneration.

Development of a novel virus-like particle-based vaccine for preventing tick-borne encephalitis virus infection.

Tick-borne encephalitis virus (TBEV) is an important tick-borne pathogen that poses as a serious public health concern. The coverage and immunogenicity of the currently available vaccines against TBEV are relatively low; therefore, it is crucial to develop novel and effective vaccines against TBEV. The present study describes a novel strategy for the assembly of virus-like particles (VLPs) by co-expressing the structural (core/prM/E) and non-structural (NS2B/NS3Pro) proteins of TBEV. The efficacy of the VLPs was subsequently evaluated in C57BL/6 mice, and the resultant IgG serum could neutralize both Far-Eastern and European subtypes of TBEV. These findings indicated that the VLP-based vaccine elicited the production of cross-subtype reactive antibodies. The VLPs provided protection to mice lacking the type I interferon receptor (IFNAR-/-) against lethal TBEV challenge, with undetectable viral load in brain and intestinal tissues. Furthermore, the group that received the VLP vaccine did not exhibit significant pathological changes and the inflammatory factors were significantly suppressed compared to the control group. Immunization with the VLP vaccine induced the production of multiple-cytokine-producing antiviral CD4+ T cells in vivo, including TNF-α+, IL-2+, and IFN-γ+ T cells. Altogether, the findings suggest that noninfectious VLPs can serve as a potentially safe and effective vaccine candidate against diverse subtypes of TBEV.

TRIB1 regulates liver regeneration by antagonizing the NRF2-mediated antioxidant response.

Robust regenerative response post liver injuries facilitates the architectural and functional recovery of the liver. Intrahepatic redox homeostasis plays a key role in liver regeneration. In the present study, we investigated the contributory role of Tribbles homolog 1 (Trib1), a pseudokinase, in liver regeneration and the underlying mechanism. We report that Trib1 expression was transiently down-regulated in animal and cell models of liver regeneration. Further analysis revealed that hepatocyte growth factor (HGF) repressed Trib1 transcription by evicting liver X receptor (LXRα) from the Trib1 promoter. Knockdown of Trib1 enhanced whereas over-expression of Trib1 suppressed liver regeneration after partial hepatectomy in mice. Of interest, regulation of liver regenerative response by Trib1 coincided with alterations of intracellular ROS levels, GSH levels, and antioxidant genes. Transcriptional assays suggested that Trib1 influenced cellular redox status by attenuating nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Mechanistically, Trib1 interacted with the C-terminus of Nrf2 thus masking a potential nuclear localization signal (NLS) and blocking nuclear accumulation of Nrf2. Finally, correlation between Trib1 expression, Nrf2 nuclear localization, and cell proliferation was identified in liver specimens taken from patients with acute liver failure. In conclusion, our data unveil a novel pathway that depicts Trib1 as a critical link between intracellular redox homeostasis and cell proliferation in liver regeneration.

Serum response factor activates peroxidasin transcription to block senescence of hepatic stellate cells.

AIMS: Aberrant liver fibrosis is a hallmark event in end-stage liver diseases. Hepatic stellate cells (HSCs) are considered the major source of myofibroblasts in the liver that produce extracellular matrix proteins to promote liver fibrosis. HSCs undergo senescence in response to various stimuli, a process that can be exploited to dampen liver fibrosis. We investigated the role of serum response factor (SRF) in this process. METHODS AND MATERIALS: Senescence was induced HSCs by serum withdrawal or progressive passage. DNA-protein interaction was evaluated by chromatin immunoprecipitation (ChIP). RESULTS: SRF expression was down-regulated in HSCs entering into senescence. Coincidently, SRF depletion by RNAi accelerated HSC senescence. Of note, treatment of an anti-oxidant (N-acetylcysteine or NAC) blocked HSC senescence by SRF deficiency suggesting that SRF may antagonize HSC senescence by eliminating excessive reactive oxygen species (ROS). PCR-array based screening identified peroxidasin (PXDN) as a potential target for SRF in HSCs. PXDN expression was inversely correlated with HSC senescence whereas PXDN knockdown accelerated HSC senescence. Further analysis reveals that SRF directly bound to the PXDN promoter and activated PXDN transcription. Consistently, PXDN over-expression protected whereas PXDN depletion amplified HSC senescence. Finally, PXDN knockout mice displayed diminished liver fibrosis compared to wild type mice when subjected to bile duct ligation (BDL). SIGNIFICANCE: Our data suggest that SRF, via its downstream target PXDN, plays a key role in regulating HSC senescence.

Identification of a Prunus MAX1 homolog as a unique strigol synthase.

Strigol is the first identified and one of the most important strigolactones (SLs), but the biosynthetic pathway remains elusive. We functionally identified a strigol synthase (cytochrome P450 711A enzyme) in the Prunus genus through rapid gene screening in a set of SL-producing microbial consortia, and confirmed its unique catalytic activity (catalyzing multistep oxidation) through substrate feeding experiments and mutant analysis. We also reconstructed the biosynthetic pathway of strigol in Nicotiana benthamiana and reported the total biosynthesis of strigol in the Escherichia coli-yeast consortium, from the simple sugar xylose, which paves the way for large-scale production of strigol. As proof of concept, strigol and orobanchol were detected in Prunus persica root extrudes. This demonstrated a successful prediction of metabolites produced in plants through gene function identification, highlighting the importance of deciphering the sequence-function correlation of plant biosynthetic enzymes to more accurately predicate plant metabolites without metabolic analysis. This finding revealed the evolutionary and functional diversity of CYP711A (MAX1) in SL biosynthesis, which can synthesize different stereo-configurations of SLs (strigol- or orobanchol-type). This work again emphasizes the importance of microbial bioproduction platform as an efficient and handy tool to functionally identify plant metabolism.

Zinc finger transcription factor Egf1 promotes non-alcoholic fatty liver disease.

Background & Aims: Non-alcoholic fatty liver disease (NAFLD) contributes to the global epidemic of metabolic syndrome and is considered a prelude to end-stage liver diseases such as cirrhosis and hepatocellular carcinoma. During NAFLD pathogenesis, hepatic parenchymal cells (hepatocytes) undergo both morphological and functional changes owing to a rewired transcriptome. The underlying mechanism is not entirely clear. In the present study, we investigated the involvement of early growth response 1 (Egr1) in NAFLD. Methods: Quantitative PCR, Western blotting, and histochemical staining were used to assess gene expression levels. Chromatin immunoprecipitation was used to evaluate protein binding to DNA. NAFLD was evaluated in leptin receptor-deficient (db/db) mice. Results: We report here that Egr1 was upregulated by pro-NAFLD stimuli in vitro and in vivo. Further analysis revealed that serum response factor (SRF) was recruited to the Egr1 promoter and mediated Egr1 transactivation. Importantly, Egr1 depletion markedly mitigated NAFLD in db/db mice. RNA sequencing revealed that Egr1 knockdown in hepatocytes, on the one hand, boosted fatty acid oxidation (FAO) and, on the other hand, suppressed the synthesis of chemoattractants. Mechanistically, Egr1 interacted with peroxisome proliferator-activated receptor α (PPARα) to repress PPARα-dependent transcription of FAO genes by recruiting its co-repressor NGFI-A binding protein 1 (Nab1), which potentially led to promoter deacetylation of FAO genes. Conclusions: Our data identify Egr1 as a novel modulator of NAFLD and a potential target for NAFLD intervention. Impact and Implications: Non-alcoholic fatty liver disease (NAFLD) precedes cirrhosis and hepatocellular carcinoma. In this paper, we describe a novel mechanism whereby early growth response 1 (Egr1), a transcription factor, contributes to NAFLD pathogenesis by regulating fatty acid oxidation. Our data provide novel insights and translational potential for NAFLD intervention.

Novel Alcohol-Soluble Nitroxide Radical Conjugated Polymer for Cathode Modifier of Efficient Organic Solar Cells with Enhanced Stability.

Alcohol-soluble conjugated polymers with polar side-chain components have been regarded as one of the most promising cathode interfacial modifers (CIMs) to achieve high-performance organic solar cells (OSCs). Herein, a novel alcohol-soluble nitrogen oxide radical conjugated polymer (PBN-NO) containing dimethylamine groups for regulating metal work function and the dangling of 2,2,6, 6-tetramethylpiperidine 1-oxy (TEMPO) radical side-chain groups for theoretically improving the conductivity, was prepared and characterized. As compared to the OSCs from PM6:Y6 blends with the most common CIMs of PFN, PDINO, and PDINN, the OSCs with PBN-NO as CIMs provide better or comparable power conversion efficiencies (PCEs) (16.19% vs 13.10%, 15.60%, and 16.15%), enhanced photostability, and thermal stability. Besides that, the reasons for the improving PCEs of the OSCs with PBN-NO modifier are systematically investigated and supported by a set of comparative experiments such as exciton dissociation, charge recombination, capacitance-voltage (C-V), etc. To the best of our knowledge, this is the first report of an alcohol-soluble nitroxide radical conjugated polymer that successfully integrates the interfacial modification of polar groups and improves conductivity by dangling radicals, therefore contributing to efficient OSCs with enhanced stability.

SARS-CoV-2 infection activates CREB/CBP in cellular cyclic AMP-dependent pathways.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global coronavirus disease 2019 (COVID-19) pandemic that has affected the lives of billions of individuals. However, the host-virus interactions still need further investigation to reveal the underling mechanism of SARS-CoV-2 pathogenesis. Here, transcriptomics analysis of SARS-CoV-2 infection highlighted possible correlation between host-associated signaling pathway and virus. In detail, cAMP-protein kinase (PKA) pathway has an essential role in SARS-CoV-2 infection, followed by the interaction between cyclic AMP response element binding protein (CREB) and CREB-binding protein (CBP) could be induced and leading to the enhancement of CREB/CBP transcriptional activity. The replication of Delta and Omicron BA.5 were inhibited by about 49.4% and 44.7% after knockdown of CREB and CBP with small interfering RNAs, respectively. Furthermore, a small organic molecule naphthol AS-E (nAS-E), which targets on the interaction between CREB and CBP, potently inhibited SARS-CoV-2 wild-type (WT) infection with comparable the half-maximal effective concentration (EC50 ) 1.04 µM to Remdesivir 0.57 µM. Compared with WT virus, EC50 in Calu-3 cells against Delta, Omicron BA.2, and Omicron BA.5 were, on average, 1.5-fold, 1.1-fold, and 1.5-fold higher, respectively, nAS-E had a satisfied antiviral effect against Omicron variants. Taken together, our study demonstrated the importance of CREB/CBP induced by cAMP-PKA pathway during SARS-CoV-2 infection, and further provided a novel CREB/CBP interaction therapeutic drug targets for COVID-19.

High-Efficiency Fast-Radiative Blue-Emitting Perovskite Nanoplatelets and Their Formation Mechanisms.

High-efficiency blue perovskite emitters with fast fluorescence radiation are not only crucial to achieving high-quality displays but also highly desired for optical wireless communications and quantum information technologies. Here, we demonstrate the preparation of blue-emitting Eu3+-, Sb3+-, and Ba2+-induced CsPbBr3 nanoplatelets with narrow spectral widths. Among them, Sb3+-doped CsPbBr3 NPLs can reach a photoluminescence quantum yield of 95%, with a very short fluorescence lifetime of 1.48 ns and greatly reduced ligand dosage. Through nuclear magnetic resonance analysis and density functional theory calculations, we find that the dopant-ligand interaction and dopant-induced growth energy barrier decide the growth kinetics of doped nanoplatelets. These mechanisms offer a fresh route to controlling the dimension of nanoscale perovskite emitters and benefit the development of fast-radiative perovskite emitters.

The structure of the Clostridium thermocellum RsgI9 ectodomain provides insight into the mechanism of biomass sensing.

Clostridium thermocellum is actively being developed as a microbial platform to produce biofuels and chemicals from renewable plant biomass. An attractive feature of this bacterium is its ability to efficiently degrade lignocellulose using surface-displayed cellulosomes, large multi-protein complexes that house different types of cellulase enzymes. Clostridium thermocellum tailors the enzyme composition of its cellulosome using nine membrane-embedded anti-σ factors (RsgI1-9), which are thought to sense different types of extracellular carbohydrates and then elicit distinct gene expression programs via cytoplasmic σ factors. Here we show that the RsgI9 anti-σ factor interacts with cellulose via a C-terminal bi-domain unit. A 2.0 Å crystal structure reveals that the unit is constructed from S1C peptidase and NTF2-like protein domains that contain a potential binding site for cellulose. Small-angle X-ray scattering experiments of the intact ectodomain indicate that it adopts a bi-lobed, elongated conformation. In the structure, a conserved RsgI extracellular (CRE) domain is connected to the bi-domain via a proline-rich linker, which is expected to project the carbohydrate-binding unit ~160 Å from the cell surface. The CRE and proline-rich elements are conserved in several other C. thermocellum anti-σ factors, suggesting that they will also form extended structures that sense carbohydrates.

[Clinical and Cytogenetical Characteristics in Acute Myeloid Leukemia with Myelodysplasia-Related Changes].

OBJECTIVE: To explore the clinical and cytogenetic characteristics of acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) based on morphology define. METHODS: A total of 180 newly diagnosed acute myeloid leukemia (AML) patients were enrolled and retrospectively analyzed, and marrow cell morphology of 126 patients were re-evaluated. The clinical and cytogenetic characteristics, including ages, sex, WBC count, HGB level, PLT count, blasts percentage, abnormal karyotype detection rate of the patients in AML with multilineage dysplasia (AML-MRC-1), secondary AML from myelodysplastic/ myeloproliferative neoplasms (MDS/MPN) (AML-MRC-2), and AML not otherwise specified (AML-NOS) groups were investigated. RESULTS: There was no significant differences between the patients in three groups in terms of sex, age and platelet count (P=0.898, P=0.365, P=0.853), but AML-MRC-2 group (73.2%) was higher than AML-MRC-1 (60.0%) and AML-NOS (56.4%) in the percentages of patients over 60 years old (P=0.228); there were statistically significant differences on WBC count, HGB level, and blasts percentage (P=0.000, P=0.022, P=0.000, AML-MRC-2

Flexible triboelectric nanogenerator based on polyester conductive cloth for biomechanical energy harvesting and self-powered sensors.

As a new nanotechnology of mechanical energy harvesting and self-powered sensing, triboelectric nanogenerators (TENGs) have been explored as a new path of using various low-frequency disordered mechanical energies in the surrounding environment to provide power and/or sensing. However, the research of TENGs that provide full flexibility and environmental friendliness is still limited. Herein, a flexible single-electrode TENG (S-TENG) based on polyester conductive cloth as the working electrode is developed to harvest human motion energy for powering light emitting diodes (LEDs) and portable electronics. The flat conductive cloth was wrapped in a flexible elastomer. Defatted cowhide was firstly selected as a friction positive charge material for TENGs. When the size of the fabricated S-TENG is 40 × 100 mm2, high output performance has been achieved and it can generate an open-circuit voltage of 534 V and a power density of 230 mW m-2 at an operation frequency of 3.0 Hz. After integrating with a rectifier, the S-TENG can power 240 LEDs, charge various capacitors, and drive an electronic watch or a calculator. Moreover, the S-TENG can harvest the biomechanical energy of wrist movement, hand tapping, and human walking. Meanwhile, the S-TENG as a self-powered sensor can be employed to monitor subtle signals of human physiological activities, such as finger motion, facial masseter activity, and diaphragmatic breathing. Additionally, the S-TENG can be attached to clothes (such as wool coats, polyamide sweaters) to harvest the energy of cuff movement. Therefore, this work provides new insights for clean power sources of skin-mounted electronics and promotes the development of a sustainable energy supply for wearable and portable electronics.

Establishment of strigolactone-producing bacterium-yeast consortium.

Strigolactones (SLs) are a class of phytohormones playing diverse roles in plant growth and development, yet the limited access to SLs is largely impeding SL-based foundational investigations and applications. Here, we developed Escherichia coli­Saccharomyces cerevisiae consortia to establish a microbial biosynthetic platform for the synthesis of various SLs, including carlactone, carlactonoic acid, 5-deoxystrigol (5DS; 6.65 ± 1.71 µg/liter), 4-deoxyorobanchol (3.46 ± 0.28 µg/liter), and orobanchol (OB; 19.36 ± 5.20 µg/liter). The SL-producing platform enabled us to conduct functional identification of CYP722Cs from various plants as either OB or 5DS synthase. It also allowed us to quantitatively compare known variants of plant SL biosynthetic enzymes in the microbial system. The titer of 5DS was further enhanced through pathway engineering to 47.3 µg/liter. This work provides a unique platform for investigating SL biosynthesis and evolution and lays the foundation for developing SL microbial production process.

Current Understanding of Osteoimmunology in Certain Osteoimmune Diseases.

The skeletal system and immune system seem to be two independent systems. However, there in fact are extensive and multiple crosstalk between them. The concept of osteoimmunology was created to describe those interdisciplinary events, but it has been constantly updated over time. In this review, we summarize the interactions between the skeletal and immune systems in the co-development of the two systems and the progress of certain typical bone abnormalities and bone regeneration on the cellular and molecular levels according to the mainstream novel study. At the end of the review, we also highlighted the possibility of extending the research scope of osteoimmunology to other systemic diseases. In conclusion, we propose that osteoimmunology is a promising perspective to uncover the mechanism of related diseases; meanwhile, a study from the point of view of osteoimmunology may also provide innovative ideas and resolutions to achieve the balance of internal homeostasis.

Circulating trophoblast cell clusters for early detection of placenta accreta spectrum disorders.

Placenta accreta spectrum (PAS) is a high-risk obstetrical condition associated with significant morbidity and mortality. Current clinical screening modalities for PAS are not always conclusive. Here, we report a nanostructure-embedded microchip that efficiently enriches both single and clustered circulating trophoblasts (cTBs) from maternal blood for detecting PAS. We discover a uniquely high prevalence of cTB-clusters in PAS and subsequently optimize the device to preserve the intactness of these clusters. Our feasibility study on the enumeration of cTBs and cTB-clusters from 168 pregnant women demonstrates excellent diagnostic performance for distinguishing PAS from non-PAS. A logistic regression model is constructed using a training cohort and then cross-validated and tested using an independent cohort. The combined cTB assay achieves an Area Under ROC Curve of 0.942 (throughout gestation) and 0.924 (early gestation) for distinguishing PAS from non-PAS. Our assay holds the potential to improve current diagnostic modalities for the early detection of PAS.

Management of systemic risk factors ahead of dental implant therapy: A beard well lathered is half shaved.

As the most successful therapy for missing teeth, dental implant has become increasingly prevalent around the world. A lot of papers have reported diverse local risk factors affecting the success and survival rate of dental implants, either for a short or a long period. However, there are also many types of systemic disorders or relatively administrated medicine that may jeopardize the security and success of dental implant treatment. Additionally, the coronavirus disease 2019 pandemic also poses a challenge to dental implant clinicians. Some of these risk factors are clinically common but to some extent unfamiliar to dentists, thus optimal measurements are often lacking when they occur in dental clinics. In this review, we analyze potential systemic risk factors that may affect the success rate of dental implants. Some of them may affect bone mineral density or enhance the likelihood of local infection, thus impeding osseointegration. Others may even systemically increase the risk of the surgery and threaten patients' life. In order to help novices receive high-risk patients who need to get dental implant treatment in a more reasonable way, we accordingly review recent research results and clinical experiments to discuss promising precautions, such as stopping drugs that impact bone mineral density or the operation, and addressing any perturbations on vital signs.

[Concentrations, Sources, and Health Risks of PM2.5 Carrier Metals in the Beijing Urban Area and Suburbs].

To explore the differences in pollution characteristics, sources, and health risks of PM2.5 carrier metals in urban and suburban areas in Beijing, daily PM2.5 samples were collected from Haidian and Daxing from June to November 2017 and the concentration of PM2.5 and 13 constituent metals were analyzed. The sources of these 13 metal elements were analyzed by positive matrix factorization (PMF), and the health hazards of a subset of 9 metals were evaluated using health risk assessment. The results showed that the concentrations of PM2.5 and 10 metal concentrations in the urban area including Cr, Co, Mn, and Ni were significantly different from those in suburban areas (P<0.05). The source analysis results show four key sources, although their relative contributions vary slightly between urban and rural areas. In urban areas, the main sources are motor vehicles (51.2%), coal burning (19.1%), dust (19.3%), and fuel oil (10.4%); in the suburbs, sources are motor vehicles (47.9%), coal burning (22.6%), dust (20.2%), and electroplating (9.3%). The results of the health risk assessment showed that all metal HQ values in the suburbs were less than 1, and there was no non-carcinogenic risk. Ni and Pb in urban areas, and Cd, Co, Ni, and Pb in suburban areas, do not present a cancer risk, while the R values of As (2.77×10-5), Cd (2×10-6), Co (1.76×10-6), and Cr(Ⅵ) (7.88×10-6) in urban areas and As (8.34×10-6) and Cr(Ⅵ) (4.94×10-6) in suburban areas present some risk of cancer.