YTHDF1's grip on CRC vasculature: insights into LINC01106 and miR-449b-5p-VEGFA axis.

BACKGROUND: Investigating the unexplored territory of lncRNA m6A modification in colorectal cancer (CRC) vasculature, this study focuses on LINC01106 and YTHDF1. METHODS: Clinical assessments reveal upregulated LINC01106 promoting vascular generation via the miR-449b-5p-VEGFA pathway. RESULTS: YTHDF1, elevated in CRC tissues, emerges as an adverse prognostic factor. Functional experiments showcase YTHDF1's inhibitory effects on CRC cell dynamics. Mechanistically, Me-CLIP identifies m6A-modified LINC01106, validated as a YTHDF1 target through Me-RIP. CONCLUSIONS: This study sheds light on the YTHDF1-mediated m6A modification of LINC01106, presenting it as a key player in suppressing CRC vascular generation.

Trends and patterns of antibiotic using from 2014 to 2018 in stomatology hospitals of China.

OBJECTIVE: To analyze trends of antibiotic consumption and expenditure in Chinese stomatology hospitals between 2014 and 2018 with a longitudinal study design, and show the impacts of the comprehensive policy on dental antibiotic use in China. SUBJECT AND METHODS: Consumption was quantified as the number of daily defined doses (DDDs) and expenditure as the procurement costs, using medical institutions' drug procurement data from the Chinese Monitoring Network for Rational Use of Drugs. Descriptive statistics was employed and the compound annual growth rate (CAGR) was calculated to show the average annual growth rate. RESULTS: Between 2014 and 2018, overall antibiotic consumption increased from 842.6 thousand DDDs to 1376.7 thousand DDDs (p < 0.001) and expenditure increased from 11.6 million RMB to 20.9 million RMB (p < 0.001), where other ß-lactam antibacterials accounted for the largest proportion of total consumption (37.1%-50.1%) and expenditure (52.9%-66.6%), and also increase the largest (CAGR = 18.4%, p < 0.001). The proportion of oral antibiotics was nearly 9 times of parenteral antibiotics in consumption (CAGR = 0.3%, p = 0.023) and only 2 times in expenditure (CAGR = -1.7%, p = 0.112). The non-restricted group accounted for more than 90% of consumption (CAGR = 0.6%, p < 0.001). In 2018, oral first-generation cephalosporins (22.8%), oral imidazole derivatives (22.3%), and oral second-generation cephalosporins (19.2%) were the most frequently used antibiotic classification, while parenteral second-generation cephalosporins were top one (19.8%) for expenditure. At chemical substance levels, the consumption of oral cefradine ranked top one (21.4%) and parenteral cefuroxime accounted for the largest proportion of expenditure (14.5%) in 2018. Oral cefradine, oral metronidazole, and oral cefaclor were the top three frequently consumed antibiotics throughout the five years. CONCLUSIONS: Despite the potential antibiotic overuse, the comprehensive antibiotic stewardship regulations of China got a satisfactory and better performance in dental practices. More effort is needed to establish more explicit guidelines to improve antibiotic stewardship, such as priority recommending amoxicillin and its derivatives for endodontic infections.

Air-plant interaction and air-soil exchange of polycyclic aromatic hydrocarbons in a large human-influenced reservoir in southwest China.

The Three Gorges Reservoir (TGR) is totally manmade, strongly influenced by anthropogenic activity, and lies on the upper reaches of Yangtze River. The periodic storage and discharge of water from the Three Gorges Dam could have altered the original air-plant/soil interactions of contaminants in TGR. Herein, paired atmospheric gas-particle, air-plant, and air-soil samples were collected to investigate the air-plant interaction and air-soil exchange of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs). The air-plant interaction based on McLachlan's framework to our datasets suggests that PAHs were absorbed via gaseous deposition that was restricted by the plant-gas dynamic equilibrium. The equilibrium indicates a dynamic balance between the gaseous phase and plant surface in PAH absorption. The main limiting factor influencing the PAH uptake was the plant species rather than the atmospheric PAH concentration. The air-soil exchange of PAHs exhibited a net volatilization flux of 16.71 ng/m2/d from the soil to the air based on annual average. There was more volatilization and less deposition in summer and more deposition and less volatilization in autumn and winter. The soil serves as a secondary source of atmospheric PAHs. As the first attempt on probing the multi-interface geochemical process of PAHs, this study highlights the influence of manual water level manipulation from the TGD and environmental factors (such as temperature, humidity, and soil properties) on the regional fate of PAHs in the TGR.

MdbZIP44-MdCPRF2-like-Mdα-GP2 regulate starch and sugar metabolism in apple under nitrogen supply.

Nitrogen (N) is regarded as an essential macronutrient and is tightly associated with carbon (C) metabolism in plants. The transcriptome data obtained from this study showed that the expression level of the apple basic leucine zipper (bZIP) transcription factor (TF) MdbZIP44 was up-regulated in 'Oregon Spur Delicious' (Malus domestica Borkh.) apple fruits under nitrogen supply. MdbZIP44 bound to the promoter of Mdα-GP2 gene and inhibited its expression, thereby promoting starch accumulation and decreasing glucose content in apple and tomato fruits. Besides, overexpression of MdbZIP44 promoted sucrose accumulation by regulating the activities of sucrose metabolism-related enzymes and the expression of sugar metabolism-related genes in apple callus and tomato fruits. Furthermore, biochemical assays indicated that MdbZIP44 directly interacted with MdCPRF2-like, another bZIP gene in apple. Meanwhile, this study found that MdCPRF2-like, along with the MdbZIP44 and MdCPRF2-like complex, could activate the expression of Mdα-GP2, respectively. In conclusion, this study provides a new reference for potential mechanisms underlying that MdbZIP44-MdCPRF2-like-Mdα-GP2 regulates starch and sugar metabolism under nitrogen supply.

The LEPIS-HuR-TMOD4 axis regulates hepatic cholesterol homeostasis and accelerates atherosclerosis.

BACKGROUND AND AIMS: Long noncoding RNAs (lncRNAs) play important roles in the progression of atherosclerosis. In this study, we identified an uncharacterized lncRNA, Liver Expressions by PSRC1 Induced Specifically (LEPIS). This study aimed to clarify the mechanism though which LEPIS affects atherosclerosis (AS). METHODS: The expression of LEPIS and its potential target, tropomodulin 4 (TMOD4), was increased in the livers of ApoE-/- mice fed a high-fat diet (HFD). An ApoE-/- mouse model in which LEPIS or TMOD4 was overexpressed in the liver was established. The plaque load in the aorta was assessed, plasma was collected to measure blood lipid levels, and the liver was collected to study cholesterol metabolism. RESULTS: We found that both LEPIS and TMOD4 increased the AS burden and reduced hepatic cholesterol levels. A further study revealed that LEPIS and TMOD4 affected the expression of genes related to hepatic cholesterol homeostasis, including proprotein convertase subtilisin/kexin type 9 (PCSK9) and low-density lipoprotein receptor (LDLR), which are closely related to hypercholesterolemia. Mechanistically, human antigen R (HuR), an RNA-binding protein (RBP), was shown to be critical for the regulation of TMOD4 by LEPIS. Furthermore, we found that verexpression of LEPIS promoted the shuttling of HuR from the nucleus to the cytoplasm, enhanced the stability of TMOD4 mRNA, and in turn promoted the expression of TMOD4. In addition, TMOD4 was found to affect intracellular cholesterol levels through PCSK9. CONCLUSIONS: These results suggest that the LEPIS-HuR-TMOD4 axis is a potential intervention target for dysregulated hepatic cholesterol homeostasis and AS and may provide the basis for further reductions in the circulating LDL-C concentration and arterial plaque burden.

Overexpression of Rhodiola crenulata glutathione peroxidase 5 increases cold tolerance and enhances the pharmaceutical value of the hairy roots.

Rhodiola crenulata, a plant of great medicinal value found in cold high-altitude regions, has been excessively exploited due to the difficulty in cultivation. Understanding Rhodiola crenulata's adaptation mechanisms to cold environment can provide a theoretical basis for artificial breeding. Glutathione peroxidases (GPXs), critical enzymes found in plants, play essential roles in antioxidant defense through the ascorbate-glutathione cycle. However, it is unknown whether GPX5 contributes to Rhodiola crenulata's cold tolerance. In this study, we investigated the role of GPX5 in Rhodiola crenulata's cold tolerance mechanisms. By overexpressing Rhodiola crenulata GPX5 (RcGPX5) in yeast and Arabidopsis thaliana, we observed down-regulation of Arabidopsis thaliana GPX5 (AtGPX5) and increased cold tolerance in both organisms. Furthermore, the levels of antioxidants and enzyme activities in the ascorbate-glutathione cycle were elevated, and cold-responsive genes such as AtCBFs and AtCORs were induced. Additionally, RcGPX5 overexpressing lines showed insensitivity to exogenous abscisic acid (ABA), suggesting a negative regulation of the ABA pathway by RcGPX5. RcGPX5 also promoted the expression of several thioredoxin genes in Arabidopsis and interacted with two endogenous genes of Rhodiola crenulata, RcTrx2-3 and RcTrxo1, located in mitochondria and chloroplasts. These findings suggest a significantly different model in Rhodiola crenulata compared to Arabidopsis thaliana, highlighting a complex network involving the function of RcGPX5. Moreover, overexpressing RcGPX5 in Rhodiola crenulata hairy roots positively influenced the salidroside synthesis pathway, enhancing its pharmaceutical value for doxorubicin-induced cardiotoxicity. These results suggested that RcGPX5 might be a key component for Rhodiola crenulata to adapt to cold stress and overexpressing RcGPX5 could enhance the pharmaceutical value of the hairy roots.

Exosomal lncRNA DUXAP8 affecting CHPF2 in the pathogenesis of intracranial aneurysms.

OBJECTIVE: This study endeavored to explore the relationship between exosome-derived lncRNA Double Homeobox A Pseudogene 8 (DUXAP8) and Chondroitin Polymerizing Factor 2 (CHPF2), and their roles in the pathogenesis of intracranial aneurysm (IA). METHODS: The shared targeted molecules (DUXAP8 and CHPF2) were detected via GSE122897 and GSE75436 datasets. A total of 312 patients with IAs were incorporated into this study. Exosomes were isolated from serum samples, and their identity was confirmed using Western blotting for exosomal markers (CD9, CD63 and ALIX). Inflammatory responses in IA tissues were evaluated using Hematoxylin-Eosin staining. CHPF2 protein concentration and the expression levels of DUXAP8 and CHPF2 mRNA in exosomal samples were assessed using Immunochemistry (IHC), Western Blotting, and qRT-PCR, respectively. Cell-based assays involving Human Umbilical Vein Endothelial Cells (HuvECs), including transfection with exosomal DUXAP8, Western Blotting, qRT-PCR, and Cell Counting Kit-8, were conducted. Receiver Operating Characteristic (ROC) curves were derived using SPSS. RESULTS: DUXAP8 level affects the level of CHPF2. DUXAP8 expression within exosomes was associated with increased CD9, CD63, ALIX and CHPF2 levels during IA development and inflammatory stress. In HuvECs, transfection with exosomes carrying DUXAP8 siRNA resulted in reduced CHPF2 expression, whereas DUXAP8 mimic increased CHPF2 concentrations. The Area Under the ROC Curve (AUC) for exosomal DUXAP8 expression and CHPF2 levels, and aneurysm size was 0.768 (95% CI, 0.613 to 0.924), 0.937 (95% CI, 0.853 to 1.000), and 0.943 (95% CI, 0.860, 1.000), respectively. CONCLUSION: Exosome-derived DUXAP8 promotes IA progression by affecting CHPF2 expression.

APE1 inhibition enhances ferroptotic cell death and contributes to hepatocellular carcinoma therapy.

Ferroptosis, a regulated form of cell death triggered by iron-dependent lipid peroxidation, has emerged as a promising therapeutic strategy for cancer treatment, particularly in hepatocellular carcinoma (HCC). However, the mechanisms underlying the regulation of ferroptosis in HCC remain to be unclear. In this study, we have identified a novel regulatory pathway of ferroptosis involving the inhibition of Apurinic/apyrimidinic endonuclease 1 (APE1), a key enzyme with dual functions in DNA repair and redox regulation. Our findings demonstrate that inhibition of APE1 leads to the accumulation of lipid peroxidation and enhances ferroptosis in HCC. At the molecular level, the inhibition of APE1 enhances ferroptosis which relies on the redox activity of APE1 through the regulation of the NRF2/SLC7A11/GPX4 axis. We have identified that both genetic and chemical inhibition of APE1 increases AKT oxidation, resulting in an impairment of AKT phosphorylation and activation, which leads to the dephosphorylation and activation of GSK3ß, facilitating the subsequent ubiquitin-proteasome-dependent degradation of NRF2. Consequently, the downregulation of NRF2 suppresses SLC7A11 and GPX4 expression, triggering ferroptosis in HCC cells and providing a potential therapeutic approach for ferroptosis-based therapy in HCC. Overall, our study uncovers a novel role and mechanism of APE1 in the regulation of ferroptosis and highlights the potential of targeting APE1 as a promising therapeutic strategy for HCC and other cancers.

TIPE2: A Candidate for Targeting Antitumor Immunotherapy.

TNF-α-induced protein 8-like 2 (TIPE2 or TNFAIP8L2) is a recently discovered negative regulator of innate and adaptive immunity. TIPE2 is expressed in a wide range of tissues, both immune and nonimmune, and is implicated in the maintenance of immune homeostasis within the immune system. Furthermore, TIPE2 has been shown to play a pivotal role in the regulation of inflammation and the development of tumor. This review focuses on the structural characteristics, expression patterns, and functional roles of TIPE proteins, with a particular emphasis on the role and underlying mechanisms of TIPE2 in immune regulation and its involvement in different diseases. However, the current body of evidence is still limited in providing a comprehensive understanding of the complex role of TIPE2 in the human body, warranting further investigation to elucidate the possible mechanisms and functions of TIPE2 in diverse disease contexts.

The role of ferroptosis in cardio-oncology.

With the rapid development of new generations of antitumor therapies, the average survival time of cancer patients is expected to be continuously prolonged. However, these therapies often lead to cardiotoxicity, resulting in a growing number of tumor survivors with cardiovascular disease. Therefore, a new interdisciplinary subspecialty called "cardio-oncology" has emerged, aiming to detect and treat cardiovascular diseases associated with tumors and antitumor therapies. Recent studies have highlighted the role of ferroptosis in both cardiovascular and neoplastic diseases. The balance between intracellular oxidative stress and antioxidant defense is crucial in regulating ferroptosis. Tumor cells can evade ferroptosis by upregulating multiple antioxidant defense pathways, while many antitumor therapies rely on downregulating antioxidant defense and promoting ferroptosis in cancer cells. Unfortunately, these ferroptosis-inducing antitumor therapies often lack tissue specificity and can also cause injury to the heart, resulting in ferroptosis-induced cardiotoxicity. A range of cardioprotective agents exert cardioprotective effects by inhibiting ferroptosis. However, these cardioprotective agents might diminish the efficacy of antitumor treatment due to their antiferroptotic effects. Most current research on ferroptosis only focuses on either tumor treatment or heart protection but rarely considers both in concert. Therefore, further research is needed to study how to protect the heart during antitumor therapies by regulating ferroptosis. In this review, we summarized the role of ferroptosis in the treatment of neoplastic diseases and cardiovascular diseases and also attempted to propose further research directions for ferroptosis in the field of cardio-oncology.

Targeting the mammalian target of rapamycin pathway in neurological manifestations of Covid-19.

The diverse and severe nature of neurological manifestations associated with coronavirus disease 2019 (Covid-19) has garnered increasing attention. Exploring the potential to decrease neurological complications in Covid-19 patients involves targeting the mammalian target of rapamycin (mTOR) pathway as a therapeutic strategy. The mTOR pathway, widely recognised for its central role in essential cellular processes like synthesising proteins, facilitating autophagy, and modulating immune responses, has implications in various neurological disorders. Drawing parallels between these disorders and the observed neurological complications in Covid-19, we present a comprehensive review on the current understanding of mTOR signalling in the context of severe acute respiratory syndrome coronavirus 2 infection and neuroinflammation.

Reducing SULT2B1 promotes the interaction of LncRNAgga3-204 with SMAD4 to inhibit the macrophage inflammatory response and delay atherosclerosis progression.

Inflammation is a crucial pathophysiological mechanism in atherosclerosis (AS). This study aims to investigate the impact of sulfotransferase family 2b member 1 (SULT2B1) on the inflammatory response of macrophages and the progression of AS. Here, we reported that SULT2B1 expression increased with the progression of AS. In AS model mice, knockdown of Sult2b1 led to remission of AS and reduced inflammation levels. Further exploration of the downstream molecular mechanisms of SULT2B1 revealed that suppressing Sult2b1 in macrophages resulted in decreased levels of 25HC3S in the nucleus, elevated expression of Lxr, and increased the transcription of Lncgga3-204. In vivo, knockdown of Lncgga3-204 aggravated the inflammatory response and AS progression, while the simultaneous knockdown of both Sult2b1 and Lncgga3-204 exacerbated AS and the inflammatory response compared with knockdown of Sult2b1 alone. Increased binding of Lncgga3-204 to SMAD4 in response to oxidized-low density lipoprotein (ox-LDL) stimulation facilitated SMAD4 entry into the nucleus and regulated Smad7 transcription, which elevated SMAD7 expression, suppressed NF-κB entry into the nucleus, and ultimately attenuated the macrophage inflammatory response. Finally, we identified the presence of a single nucleotide polymorphism (SNP), rs2665580, in the SULT2B1 promoter region in monocytes from coronary artery disease (CAD) patients. The predominant GG/AG/AA genotypes were observed in the Asian population. Elevated SULT2B1 expression in monocytes with GG corresponded to elevated inflammatory factor levels and more unstable coronary plaques. To summarize, our study demonstrated that the critical role of SULT2B1/Lncgga3-204/SMAD4/NF-κB in AS progression. SULT2B1 serves as a novel biomarker indicating inflammatory status, thereby offering insights into potential therapeutic strategies for AS.

[Identification and expression analysis of citrate synthase 3 gene family members in apple].

As one of the key enzymes in cell metabolism, the activity of citrate synthase 3 (CS3) regulates the substance and energy metabolism of organisms. The protein members of CS3 family were identified from the whole genome of apple, and bioinformatics analysis was performed and expression patterns were analyzed to provide a theoretical basis for studying the potential function of CS3 gene in apple. BLASTp was used to identify members of the apple CS3 family based on the GDR database, and the basic information of CS3 protein sequence, subcellular localization, domain composition, phylogenetic relationship and chromosome localization were analyzed by Pfam, SMART, MEGA5.0, clustalx.exe, ExPASy Proteomics Server, MEGAX, SOPMA, MEME, WoLF PSORT and other software. The tissue expression and inducible expression characteristics of 6 CS3 genes in apple were determined by acid content and real-time fluorescence quantitative polymerase chain reaction (qRT-PCR). Apple CS3 gene family contains 6 members, and these CS3 proteins contain 473-608 amino acid residues, with isoelectric point distribution between 7.21 and 8.82. Subcellular localization results showed that CS3 protein was located in mitochondria and chloroplasts, respectively. Phylogenetic analysis divided them into 3 categories, and the number of genes in each subfamily was 2. Chromosome localization analysis showed that CS3 gene was distributed on different chromosomes of apple. The secondary structure of protein is mainly α-helix, followed by random curling, and the proportion of ß-angle is the smallest. The 6 members were all expressed in different apple tissues. The overall expression trend from high to low was the highest relative expression content of MdCS3.4, followed by MdCS3.6, and the relative expression level of other members was in the order of MdCS3.3 > MdCS3.2 > MdCS3.1 > MdCS3.5. qRT-PCR results showed that MdCS3.1 and MdCS3.3 genes had the highest relative expression in the pulp of 'Chengji No. 1' with low acid content, and MdCS3.2 and MdCS3.3 genes in the pulp of 'Asda' with higher acid content had the highest relative expression. Therefore, in this study, the relative expression of CS3 gene in apple cultivars with different acid content in different apple varieties was detected, and its role in apple fruit acid synthesis was analyzed. The experimental results showed that the relative expression of CS3 gene in different apple varieties was different, which provided a reference for the subsequent study of the quality formation mechanism of apple.

Identification of important genes related to HVSMC proliferation and migration in graft restenosis based on WGCNA.

The great saphenous vein is the most commonly used vessel for coronary artery bypass grafting (CABG), but its use has been associated with a high restenosis rate at 10-year follow-up. This study sought to determine the key genes associated with vein graft restenosis that could serve as novel therapeutic targets. A total of 3075 upregulated and 1404 downregulated genes were identified after transcriptome sequencing of three pairs of restenosed vein grafts and intraoperative spare great saphenous veins. Weighted gene co-expression network analysis showed that the floralwhite module had the highest correlation with vein graft restenosis. The intersection of the floralwhite module gene set and the upregulated gene set contained 615 upregulated genes strongly correlated with vein graft restenosis. Protein-protein interaction network analysis identified six hub genes (ITGAM, PTPRC, TLR4, TYROBP, ITGB2 and CD4), which were obtained using the STRING database and CytoHubba. Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses showed that the common hub genes were mainly involved in the composition of the cell membrane; in biological processes such as neutrophil degranulation, receptor binding and intercellular adhesion, innate immune deficiency; and other signaling pathways. Finally, ITGB2 was selected as the target gene, and its expression was verified in tissues. The results showed that ITGB2 was significantly overexpressed in occluded vein grafts. To study the function of ITGB2 in HVSMCs, primary HVSMCs were cultured and successfully identified. EdU incorporation, wound healing and transwell assays showed that ITGB2 silencing significantly inhibited the proliferation and migration of HVSMCs stimulated by PDGF-BB. Overall, our study provides a basis for future studies on preventing restenosis following CABG.

A pomegranate seed-structured nanozyme-based colorimetric immunoassay for highly sensitive and specific biosensing of Staphylococcus aureus.

Staphylococcus aureus (S. aureus) infections are a serious threat to human health. The development of rapid and sensitive detection methods for pathogenic bacteria is crucial for accurate drug administration. In this research, by combining the advantages of enzyme-linked immunosorbent assay (ELISA), we synthesized nanozymes with high catalytic performance, namely pomegranate seed-structured bimetallic gold-platinum nanomaterials (Ps-PtAu NPs), which can catalyze a colorless TMB substrate into oxidized TMB (oxTMB) with blue color to achieve colorimetric analysis of S. aureus. Under the optimal conditions, the proposed biosensor could quantitatively detect S. aureus at levels ranging from 1.0 × 101 to 1.0 × 106 CFU mL-1 with a limit of detection (LOD) of 3.9 CFU mL-1. Then, an integrated color picker APP on a smartphone enables on-site point-of-care testing (POCT) of S. aureus with LOD as low as 1 CFU mL-1. Meanwhile, the proposed biosensor is successfully applied to the detection of S. aureus in clinical samples with high sensitivity and specificity.

Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments of the East China marginal seas: Significance of the terrestrial input and shelf mud deposition.

To investigate the distribution, sources, influencing factors, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in East China Marginal Seas (ECMSs) sediments, we measured the concentrations of 16 PAHs in 104 surface sediment samples collected from the ECMSs in 2014 and 2016. Total PAH concentration (∑PAHs) ranged from 4.49 to 163.66 ng/g dry weight (dry w), with 65.98 ± 33.00 (mean ± SD) ng/g dry w. The highest PAH concentrations and total organic carbon were observed in areas with fine-grained sediments in the Bohai Sea (BS), Yellow Sea (YS), and coastal East China Sea (ECS), indicating the prominent influence of regional hydrodynamics and sediment properties. The dominant PAH congener in BS and YS was BbF, whereas coastal ECS was Phe. The heterogeneity of PAH sources implies that terrestrial PAH input and shelf mud deposition have crucial roles in the source-sink processes of PAHs in a strongly human-influenced marginal sea.

A comprehensive exploration of characteristics and source attribution of carbonaceous aerosols in PM2.5 in an East China megacity.

A total of 84 PM2.5 (fine particulate matter) aerosol samples were collected between October 2020 and August 2021 within an urban site in Hangzhou, an East China megacity. Chemical species, such as organic carbon (OC), elemental carbon (EC), as well as char, soot, and n-alkanes, were analyzed to determine their pollution characteristics and source contributions. The mean yearly concentrations of OC, EC, char, soot, and total n-alkanes (∑n-alkane) were 8.76 ± 3.61 µg/m3, 1.44 ± 0.76 µg/m3, 1.21 ± 0.69 µg/m3, 0.3 ± 0.1 µg/m3, and 24.2 ± 10.6 ng/m3. The OC, EC, and ∑n-alkanes were found in the highest levels during winter and lowest during summer. There were strong correlations between OC and EC in both winter and spring, suggesting similar potential sources for these carbonaceous components in both seasons. There were poor correlations among the target pollutants due to summertime secondary organic carbon formation. Potential source contribution functions analysis showed that local pollution levels in winter and autumn were likely influenced by long-range transportation from the Plain of North China. Source index and positive matrix factorization models provided insights into the complex sources of n-alkanes in Hangzhou. Their major contributors were identified as terrestrial plant releases (32.7%), traffic emissions (28.8%), coal combustion (27.3%), and microbial activity (11.2%). Thus, controlling vehicular emissions and coal burning could be key measures to alleviate n-alkane concentrations in the atmosphere of Hangzhou, as well as other Chinese urban centers.