Adipocyte-specific FAK deletion promotes pancreatic ß-cell apoptosis via adipose inflammatory response to exacerbate diabetes mellitus.

BACKGROUND: White adipose tissue (WAT) has a key role in maintaining energy balance throughout the body, and their dysfunction take part in the regulation of diabetes mellitus. However, the internal regulatory mechanisms underlying are still unknown. METHODS AND RESULTS: We generated adipocyte-specific FAK KO (FAK-AKO) mice and investigated their phenotype. The cascade of adipocyte, macrophage in adipocyte tissues, and pancreatic ß-cells were proposed in FAK-AKO mice and validated by cell line studies using 3T3-L1, Raw264.7 and Min6. The FAK-AKO mice exhibited glucose intolerance, reduced adipose tissue mass and increased apoptosis, lipolysis and inflammatory response in adipose tissue. We further demonstrate that adipocyte FAK deletion increases ß cell apoptosis and inflammatory infiltrates into islets, which is potentiated if mice were treated with STZ. In the STZ-induced diabetes model, FAK AKO mice exhibit less serum insulin content and pancreatic ß cell area. Moreover, serum pro-inflammatory factors increased and insulin levels decreased after glucose stimulation in FAK AKO mice. In a parallel vitro experiment, knockdown or inhibition of FAK during differentiation also increased apoptosis, lipolysis and inflammatory in 3T3-L1 adipocytes, whereas the opposite was observed upon overexpression of FAK. Moreover, coculturing LPS-treated RAW264.7 macrophages with knockdown FAK of 3T3-L1 adipocytes increased macrophage pro-inflammatory response. Furthermore, conditioned medium from above stimulated Min6 cells apoptosis (with or without STZ), whereas the opposite was observed upon overexpression of FAK. Mechanistically, FAK protein interact with TRAF6 in adipocytes and knockdown or inhibition of FAK activated TRAF6/TAK1/NF-κB signaling, which exacerbates inflammation of adipocytes themselves. CONCLUSION: Adipocyte FAK deletion promotes both adipocyte apoptosis and adipose tissue inflammation. Pro-inflammatory factors released by the FAK-null adipose tissue further trigger apoptosis in pancreatic islets induced by the administration of STZ, thereby exacerbating the diabetes mellitus. This study reveals a link between FAK-mediated adipose inflammation and diabetes mellitus, a mechanism that has not been previously recognized.

Integrated Metabolomics and Transcriptomics Analyses Highlight the Flavonoid Compounds Response to Alkaline Salt Stress in Glycyrrhiza uralensis Leaves.

Glycyrrhiza uralensis is a saline-alkali-tolerant plant whose aerial parts are rich in flavonoids; however, the role of these flavonoids in saline-alkali tolerance remains unclear. Herein, we performed physiological, metabolomics, and transcriptomics analyses in G. uralensis leaves under alkaline salt stress for different durations. Alkaline salt stress stimulated excessive accumulation of reactive oxygen species and consequently destroyed the cell membrane, causing cell death, and G. uralensis initiated osmotic regulation and the antioxidant system to respond to stress. In total, 803 metabolites, including 244 flavonoids, were detected via metabolomics analysis. Differentially altered metabolites and differentially expressed genes were coenriched in flavonoid-related pathways. Genes such as novel.4890, Glyur001511s00039602, and Glyur000775s00025737 were highly expressed, and flavonoid metabolites such as 2'-hydroxygenistein, apigenin, and 3-O-methylquercetin were upregulated. Thus, flavonoids as nonenzymatic antioxidants play an important role in stress tolerance. These findings provide novel insights into the response of G. uralensis to alkaline salt stress.

High-Throughput Study of Amorphous Stability and Optical Properties of Superlattice-Like Ge-Sb-Te Thin Films.

A high-throughput ion beam sputtering system is used to synthesize compositional gradient superlattice-like (SLL) thin film libraries of Ge-Sb-Te alloys over the entire phase diagram. The optical properties and structural evolution of the Ge-Sb-Te combinatorial SLL thin film are investigated. A systematic screening over the annealing temperature, annealing time, and modulation period has elucidated the critical factors that affect the stability of the metastable phase and optical properties. It is found that amorphous stability and optical constant are highly dependent on the modulation period and chemical composition of the thin film. This data-driven approach offers new perspectives for accelerating the development of new materials with excellent optical and amorphous stability and for exploring their mechanisms, by greatly expanding the dataset of Ge-Sb-Te alloys with SLL structures through high-throughput experiments.

Patterns and drivers of avian taxonomic and phylogenetic beta diversity in China vary across geographical backgrounds and dispersal abilities.

Geographical background and dispersal ability may strongly influence assemblage dissimilarity; however, these aspects have generally been overlooked in previous large-scale beta diversity studies. Here, we examined whether the patterns and drivers of taxonomic beta diversity (TBD) and phylogenetic beta diversity (PBD) of breeding birds in China vary across (1) regions on both sides of the Hu Line, which demarcates China's topographical, climatic, economic, and social patterns, and (2) species with different dispersal ability. TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach. Variables representing climate, habitat heterogeneity, and habitat quality were employed to evaluate the effects of environmental filtering. Spatial distance was considered to assess the impact of dispersal limitation. Variance partitioning analysis was applied to assess the relative roles of these variables. In general, the values of TBD and PBD were high in mountainous areas and were largely determined by environmental filtering. However, different dominant environmental filters on either side of the Hu Line led to divergent beta diversity patterns. Specifically, climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions east and west of the line, respectively. Additionally, bird species with stronger dispersal ability were more susceptible to environmental filtering, resulting in more homogeneous assemblages. Our results indicated that regions with distinctive geographical backgrounds may present different ecological factors that lead to divergent assemblage dissimilarity patterns, and dispersal ability determines the response of assemblages to these ecological factors. Identifying a single universal explanation for the observed pattern without considering these aspects may lead to simplistic or incomplete conclusions. Consequently, a comprehensive understanding of large-scale beta diversity patterns and effective planning of conservation strategies necessitate the consideration of both geographical background and species dispersal ability.

Use of basic amino acids to improve gel properties of PSE-like chicken meat proteins isolated via ultrasound-assisted alkaline extraction.

To improve the gel quality of pale, soft, and exudative (PSE)-like chicken protein isolate (PPI) obtained via ultrasound-assisted alkaline extraction (UAE), l-lysine (l-Lys), l-arginine (l-Arg), or l-histidine (l-His) were used and the effects on the thermal gelling characteristics of PPI were studied. Compared with the nonbasic amino acid addition group, the addition of l-His/l-Arg/l-Lys significantly increased the solubility and absolute zeta potential of PPI, whereas reduced the particle size and turbidity (p < 0.05). They enhanced the gel strength and textural properties of PPI (p < 0.05) and reduced the cooking loss of PPI in the following order: l-Lys > l-Arg > l-His. The solubility, gel strength, and hardness of PPI with l-Lys were increased by 18.6%, 44.6%, and 57.6%, respectively, and cooking loss was decreased by 18.1%. Low-field nuclear magnetic resonance and magnetic resonance imaging revealed that basic amino acids addition decreased the water mobility in PPI gels with increasing immobile water content. Scanning electron microscopy revealed that the addition of basic amino acids promoted the formation of a more uniform and tight network microstructure in PPI gels. The α-helix content was decreased, whereas the ß-sheet content was increased in PPI gels after basic amino acid addition. Therefore, addition of basic amino acids, especially l-Lys, enhances the gel properties of PPI. PRACTICAL APPLICATION: This study revealed that adding basic amino acids effectively improved the gel properties of PPI obtained via UAE method, with l-Lys exerting the best improvement effect. Our findings highlight the application value of PSE-like meat by the improvement of gel characteristics of PPI, providing a theoretical reference for the processing and utilization of PPI.

Lycium barbarum glycopeptide targets PER2 to inhibit lipogenesis in glioblastoma by downregulating SREBP1c.

Lycium barbarum polysaccharide (LBP) is a substance with various biological activities extracted from Lycium barbarum. LbGPs are peptidoglycans with a short peptide backbone and a complex, branched glycan moiety, which is further extracted and isolated from LBPs. Previous studies have shown that LbGP can inhibit cancer cell growth, but its specific mechanism is not completely clear. In this study, we found that LbGP could inhibit the proliferation of glioma cells and promote the expression of period 2 (PER2) through the PKA-CREB pathway. In addition, LbGP could inhibit the de novo synthesis of lipids by downregulating SREBP1c and its target genes, which depended on the expression of PER2. Moreover, PER2 negatively regulated the expression of SREBP1c via suppressing PI3K/AKT/mTOR pathway. In summary, LbGP may upregulate the expression of PER2 to reduce the expression of SREBP1c, inhibit lipid synthesis in glioblastoma, and inhibit glioblastoma cell proliferation. This study provides an alternative drug for the treatment of glioma and elucidates its potential mechanism.

Mechanism of Key Ingredient of Astragalus membranaceus on Lung Adenocarcinoma via PI3K/AKT Signaling Clarified by Utilizing Network Pharmacology Approach and Experimental Validation.

OBJECTIVE: To investigate the mechanism of the effect of Astragalus membranaceus (A. membranaceus) on lung adenocarcinoma at the molecular level to elucidate the specific targets according to the network pharmacology approach. METHODS: The active components of A. membranaceus and their potential targets were collected from the Traditional Chinese Medicine Systems Pharmacology Database. Lung adenocarcinoma-associated genes were acquired based on GeneCards, Online Mendelian Inheritance in Man (OMIM), PharmGKB, and Therapeutic Targets databases. The PI3K/AKT signaling pathway-related genes were obtained using Reactome portal. Networks of "ingredient-target" and "ingredient-target-pathway-disease" were constructed using the Cytoscape3.6.0 software. The relationships among targets were analyzed according protein-protein interaction (PPI) network. Finally, molecular docking was applied to construct the binding conformation between active ingredients and core targets. Cell counting kit 8 (CCK8) and Western blot assays were performed to determine the mechanism of the key ingredient of A. membranaceus. RESULTS: A total of 20 active components and their 329 targets, and 7,501 lung adenocarcinoma-related genes and 130 PI3K/AKT signaling pathway-related genes were obtained. According to Venn diagram and PPI network analysis, 2 mainly active ingredients, including kaempferol and quercetin, and 6 core targets, including TP53, MAPK1, EGF, AKT1, ERBB2, and EGFR, were identified. The two important active ingredients of A. membranaceus, kaempferol and quercetin, exert the therapeutic effect in lung adenocarcinoma partly by acting on the 6 core targets (TP53, MAPK1, EGF, AKT1, ERBB2, and EGFR) of PI3K/AKT signaling pathway. Expressions of potential targets in lung adenocarcinoma and normal samples were analyzed by using UALCAN portal and found that ERBB2 was overexpressed in lung adenocarcinoma tissues and upregulation of it correlated with clinicopathological characteristics. Finally, quercetin repressed viabilities of lung adenocarcinoma cells by targeting ERBB2 on PI3K/AKT signaling confirmed by CCK8 and Western blot. CONCLUSION: Our finding unraveled that an active ingredient of A. membranaceus, quercetin, significantly inhibited the lung adenocarcinoma cells proliferation by repressing ERBB2 level and inactivating the PI3K/AKT signaling pathway.

Adipose extracellular matrix deposition is an indicator of obesity and metabolic disorders.

Obesity and metabolic disorders are threats to human health. Extracellular matrix (ECM) is an important member of adipose microenvironment. ECM remodeling contributes to obesity and insulin resistance, but the roles of every single ECM component is still not fully understood. We observed glucose and lipids metabolic disorders in high-fat diet (HFD)-fed mice and humans with obesity. Higher levels of inflammatory factors and hormones existed in serum of HFD-fed mice. Multiple collagens, laminins, fibronectin, nidogen, and Hspg2 were upregulated in obese white adipose tissue (WAT) from mice and humans. These effects were stronger in subcutaneous WAT than visceral WAT in mice, but the fat depot difference was reversed in humans. The ECM structure and the morphology of adipocytes seeded on ECM were changed in the HFD group. In human visceral WAT, ECM genes showed positive correlations with blood lipids and glucose. In vitro, collagen I/IV and LAMA4 proteins showed similar changes with C/EBPα during the differentiation of adipocytes. Macromolecular crowders (MMC) promoted partial collagen and non-collagen gene expression. Oleic acid (OA) and MMC upregulated collagen I/IV and LAMA4 proteins, and the effects of MMC were stronger than that of OA. Moreover, MMC promoted the differentiation of adipocytes, but OA increased the size of lipid droplets. Positive correlations were observed between ECM genes and adipogenesis-related genes in adipocytes. In conclusion, some obesogens (such as HFD) induce ECM remodeling, and the upregulation of ECM components is closely related to adipogenesis, suggesting that adipose ECM deposition is an indicator of obesity and metabolic disorders.

Modeling Methods and Influencing Factors for Age Estimation Based on DNA Methylation / 法医学杂志

Age estimation based on tissues or body fluids is an important task in forensic science. The changes of DNA methylation status with age have certain rules, which can be used to estimate the age of the individuals. Therefore, it is of great significance to discover specific DNA methylation sites and develop new age estimation models. At present, statistical models for age estimation have been developed based on the rule that DNA methylation status changes with age. The commonly used models include multiple linear regression model, multiple quantile regression model, support vector machine model, artificial neural network model, random forest model, etc. In addition, there are many factors that affect the level of DNA methylation, such as the tissue specificity of methylation. This paper reviews these modeling methods and influencing factors for age estimation based on DNA methylation, with a view to provide reference for the establishment of age estimation models.

Synchrotron X-Ray-Driven Nitrogen Reduction on an AgCu Thin Film.

Nitrogen (N2 ) is an essential element for life, but kinetically stable N2 in the atmosphere needs to be reduced to biologically available forms as a nutrient for organisms. Abiotic nitrogen fixation is critical to the origin of life on the early Earth, which is due to lightning or mineral-based reduction. Here, synchrotron X-ray-induced silver nitrate formation on a silver copper (AgCu) thin-film is reported. Time-resolved X-ray diffraction measurements show that under intense X-ray exposure, initially formed silver oxides (AgOx) are quickly converted to silver nitrate (AgNO3 ). Interestingly, AgNO3 is first formed in its high-temperature phase with a space group of R3cH, which gradually transforms to the room temperature phase with a space group of Pbca under continuous X-ray irradiation. The result not only provides a new clue about the abiotic nitrogen reduction prior to life but also demonstrates a novel strategy of materials synthesis using synchrotron X-rays.

Synchrotron X-ray-induced Synthesis of Copper Hydroxide Nitrate Nanoplates on Cu Thin Films in an Ambient Atmosphere.

Synchrotron X-rays are widely used for material characterizations. However, they can also ionize atoms and molecules to damage and manipulate probed materials. We report here an X-ray-induced growth of copper hydroxide nitrate, Cu2(OH)3NO3, on copper thin films in the ambient atmosphere without solvents and thermal treatment. In situ synchrotron X-ray diffraction measurements showed that the time-dependent growth process of theCu2(OH)3NO3 is accompanied by the consumption of Cu metal and can be described by a sigmoidal model. The growth rate was reduced after the initial fast growth period. Scanning electron microscopy (SEM) images show that the isolated islands of Cu2(OH)3NO3 nanoplates formed in the beginning, which grew together with new nanoplates formed under continued X-ray irradiation. The result demonstrated that high-flux synchrotron X-rays may provide an unconventional approach to synthesizing and manipulating materials, which will inspire future investigation both experimentally and theoretically.

High-Fat-Diet-Induced Extracellular Matrix Deposition Regulates Integrin-FAK Signals in Adipose Tissue to Promote Obesity.

SCOPE: High-fat-diet (HFD) is an important factor in obesity. Extracellular matrix (ECM) regulates white adipose tissue (WAT), but its mechanism is unknown. METHODS AND RESULTS: This study uses three models-HFD-fed mice, human with obesity, and 3T3-L1 adipocytes with oleic acid (OA)/macromolecular crowders (MMC) treatment. Glucose and lipids metabolic disorders, increased collagen I/IV and laminin α2/4 (LAMA2/4), and upregulated integrins (ITGA1/ITGA7) - focal adhesion kinase (FAK) - c-Jun N-terminal kinase (JNK)/extracellular regulated protein kinase 1/2 (ERK1/2) signals in obese WAT from mice and human are observed. The upregulation of ECM - integrin - FAK signals is stronger in subcutaneous WAT than that in visceral WAT of mice, but these results are reversed in human. In vitro, oleic acid (OA) promotes lipid accumulation and upregulates collagen IV, LAMA4, and p-JNK. MMC is used to induce ECM deposition in adipocytes. MMC promotes adipocyte differentiation and integrins - FAK - JNK/ERK1/2 signals. When FAK phosphorylation is inhibited, downstream p-JNK is decreased. Inhibition of FAK phosphorylation reduces adipocyte differentiation, but MMC partially reverses this effect. CONCLUSION: HFD-induced ECM deposition, whose signals are transmitted into adipocytes through upregulating ITGA1/ITGA7, activates the phosphorylation of intracellular FAK - JNK/ERK1/2 signals, and promotes adipogenesis in WAT. This mechanism provides novel therapeutic targets to treat obesity.

Clinical Value of Pepsinogen in the Screening, Prevention, and Diagnosis of Gastric Cancer.

OBJECTIVES: To compare the levels of serum pepsinogen (PG) in patients with gastric cancer (GC), patients with atrophic gastritis (AG), and healthy donors. Also, we explored the clinical value of PG detection for the diagnosis and treatment of GC. METHODS: The PG level in peripheral blood from patients and heathy donors was determined using an Abbott automatic chemiluminescence instrument. The study included 117 patients with GC confirmed by gastroscopy and histopathology, of whom 13 patients had cancer at stage I, 47 at stage II, 41 at stage III, and 16 at stage IV. The AG group included 122 patients, and the control group had 120 healthy donors. The relationship between serum PG levels and the occurrence and development of GC, as well as the evaluation of the clinical value of diagnostic tests based on serum PG detection, were investigated by receiver operating characteristic (ROC) curve analyses. RESULTS: Pepsinogen I (PGI) levels gradually decreased from the control group, the AG group, and the GC group. PGI exhibited high diagnostic value for GC (area under the curve [AUC], 0.834; cutoff, 51.2 ng/mL, sensitivity, 81.7%; specificity, 68.4%), PGII (AUC, 0.587; cutoff value, 13.05 ng/mL; sensitivity, 65.8%; specificity, 53.8%), and PGR (AUC, 0.752; cutoff, 5.65; sensitivity, 54.2%; specificity, 87.2%). The occurrence of GC was negatively correlated with serum levels of PGI (B = -0.054; OR = 0.947; 95% confidence interval [CI], 0.925-0.970; P <.001) and PGR (B = -0.420; OR = 0.657; 95% CI, 0.499-0.864; P = .003). CONCLUSIONS: The combined detection of PGI, PGII, and PGR has important clinical value for the screening, prevention, and diagnosis of GC and could allow for earlier detection, diagnosis, and treatment of GC.

A pleiotropic QTL increased economic water use efficiency in bread wheat (Triticum aestivum L.).

Wheat is one of the most important food crops in the world and drought can severely impact on wheat productivity. The identification and deployment of genes for improved water use efficiency (WUE) can help alleviate yield loss under water limitation. In this study, a high-density genetic linkage map of wheat recombinant inbred lines (Ningchun 4 x Ningchun 27) containing 8751 specific locus amplified fragment (SLAF) tags (including 14757 SNPs), with a total map distance of 1685 cM and an average inter-marker map distance of 0.19 cM was constructed by SLAF-seq technology. The economic yield WUE and nine related traits under three water treatments was monitored over four years. The results showed that loci conditioning WUE were also associated with grain carbon isotope discrimination (CID), flag leaf chlorophyll content, plant height, 1000-grain weight, grain weight per spike and grain number per spike. One locus on chromosome 2B explained 26.3% WUE variation in multiple environments. Under good soil moisture conditions before flowering, the high CID genotype QWue.acn-2B Ningchun 27, was associated with WUE, high grain weight per spike, and kilo-grain weight. Under rain-fed conditions, the low CID genotype QWue.acn-2B Ningchun 4 tended to maintain more spike number and was associated with improved WUE and yield. The introduction of good chromosome fragments of QWue.acn-2B into elite lines by molecular marker assisted selection will boost up the cultivation of high-yield and water-saving wheat varieties.

The impact of COVID-19 on short-term prognosis of ST-segment elevation myocardial infarction patients receiving primary percutaneous coronary intervention in Wuhan China.

ST-segment elevation myocardial infarction (STEMI) is a common cardiovascular emergency for which timely reperfusion therapies are needed to minimize myocardial necrosis. The aim of this study was to investigate the impact of the COVID-19 pandemic and reorganization of chest pain centers (CPC) on the practice of primary percutaneous coronary intervention (PPCI) and prognosis of STEMI patients. This single-center retrospective survey included all patients with STEMI admitted to our CPC from January 22, 2020 to April 30, 2020 (during COVID-19 pandemic in Wuhan), compared with those admitted during the analogous period in 2019, in respect of important time points of PPCI and clinical outcomes of STEMI patients. In the present article, we observed a descending trend in STEMI hospitalization and a longer time from symptom onset to first medical contact during the COVID-19 pandemic as compared to the control period (4.35 h versus 2.58 h). With a median delay of 17 minutes in the door to balloon time (D2B), the proportion of in-hospital cardiogenic shock was significantly higher in the COVID-19 era group (47.6% versus 19.5%), and major adverse cardiac events (MACE) tend to increase in the 6-month follow-up period (14.3% versus 2.4%). Although the reorganization of CPC may prolong the D2B time, immediate revascularization of the infarct-related artery could be offered to most patients within 90 minutes upon arrival. PPCI remained the preferred treatment for patients with STEMI during COVID-19 pandemic in the context of timely implementation and appropriate protective measures.

Maternal nicotine exposure impairs brown adipose tissue via AMPK-SIRT1-PGC-1α signals in male offspring.

AIMS: Maternal nicotine exposure during pregnancy and lactation is associated with obesity in offspring. Brown adipose tissue (BAT) is correlated with energy metabolism and obesity. In this study, we explored the mechanism of maternal nicotine exposure on BAT changes in male offspring. MAIN METHODS: Pregnant rats were randomly assigned to nicotine (1.0 mg/kg twice per day, subcutaneous administration) or control groups. In vitro, C3H10T1/2 cells were induced to differentiate into mature brown adipocytes, and 0-50 µM nicotine was given to C3H10T1/2 cells during the differentiation process. KEY FINDINGS: Nicotine-exposed males had white-like adipocytes and abnormal mitochondria structure in iBAT at 26 weeks. The expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway were downregulated in the nicotine group at 26 weeks rather than 4 weeks. In vitro, 50 µM nicotine decreased the expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway in brown adipocytes. SIGNIFICANCE: Maternal nicotine exposure showed the "programming" effect on the decreased brown-like phenotype in BAT of adult male offspring via downregulating AMPK-SIRT1-PGC-1α pathway. This impairment of BAT may be a potential mechanism of nicotine-induced obesity in male offspring.

Ear ischemia induced by endovascular therapy for arteriovenous fistula of the sigmoid sinus: A case report.

BACKGROUND: Arteriovenous fistula of the sigmoid sinus is an abnormal connection of arteries with the sigmoid sinus. Endovascular treatments of such lesions are considered safe and with low rates of complications. CASE SUMMARY: A 62-year-old female patient underwent endovascular treatment of an arteriovenous fistula of the right sigmoid sinus on February 7, 2017, but her tinnitus was not cured. She was admitted to the Beijing Tiantan Hospital, Capital Medical University, on March 20, 2017, and her pre-operative diagnosis, by digital subtraction cerebral angiography, was arteriovenous fistula of the sigmoid sinus. She underwent endovascular embolization of the distal occipital artery and posterior auricular artery using Onyx-18. The arteriovenous fistula of the sigmoid sinus was cured, and her tinnitus disappeared, but ischemia of the upper 2/3 of the right auricle occurred without hearing loss. The patient received treatment to improve microcirculation, in addition to fluid supplementation, analgesia, and hyperbaric oxygen, and the swelling due to ischemia in the right auricle did not progress further. The patient reported no tinnitus , and the right auricle had returned to normal 3 years later. CONCLUSION: Ischemic complications of vital organs should be considered when performing embolization procedures for arteriovenous fistulas of cerebral sinuses. Compensation of the organs should be evaluated before the operation, and the related treatment regimens should be planned.

Determining the level of extra-pair paternity in yellow-bellied prinias, a socially monogamous passerine.

Previous work based on molecular evidence has shown that most socially monogamous birds follow a genetic polyandrous mating system. However, our knowledge about avian mating systems is heavily biased toward the north temperate zone, with data on tropical birds remaining relatively scarce. This uneven distribution of both phylogenetic and spatial sampling has hampered our understanding and interpretation of results. In this study, we investigated the frequency of extra-pair paternity (EPP) in a tropical population of yellow-bellied prinias ( Prinia flaviventris) in Guangxi, southern China. A total of 129 individuals belonging to 24 nests were sampled, among which 12 out of 83 chicks (14.46%) in seven nests were found to be EPP offspring. In nests in which all nestlings were sampled, only five out of 56 chicks were EPP offspring, accounting for an unbiased EPP rate of 8.93%. This rate is below the average rate of EPP in the family Sylviidae. The possible causes of EPP in prinias and the occurrence of EPP in birds with high resource investment and intensive parental care are discussed. This study highlights the value of genome-wide markers in determining relatedness in a wild bird species without a reference genome.