Application of intestinal microbiota in marine fish for assessing the toxicity of typical pollutants: a literature review
The widespread diffusion and dilution of pollutants in the ocean lead to prolonged exposure of marine organisms to low-concentration contaminated environments, raising growing concerns about the potential risks associated with chronic low-level pollution. The gut microbiota of fish plays a pivotal role in essential physiological processes, which are critical for host health. Therefore, the key microbes in the gut could serve as valuable biomarkers for assessing the toxic effects of pollutants. This article systematically reviews the structure and functions of marine fish gut microbiota, outlines the primary methodologies for assessing gut microbiota, and highlights the impacts of typical pollutants (including petroleum hydrocarbons, antibiotics, heavy metals, and microplastic) on the composition, functionality, and metabolic activities of marine fish gut microbiota. In the future, integrating multi-technology approaches to investigate the toxic mechanisms of pollutants on gut microbiota and their biodegradation pathways will represent a pivotal direction in marine ecotoxicology research.
Feng et al. (2025) Application of intestinal microbiota in marine fish for assessing the toxicity of typical pollutants: a literature review. PeerJ 13:e20248 https://doi.org/10.7717/peerj.20248
Diagnostic and prognostic implications of growth differentiation factor 15 in heart failure with preserved ejection fraction: a systematic review and meta-analysis
Background Growth differentiation factor-15 (GDF-15), an emerging biomarker associated with chronic inflammation and oxidative stress, shows potential diagnostic and prognostic significance for heart failure with preserved ejection fraction (HFpEF). This study aimed to assess the diagnostic and prognostic value of GDF-15 in HFpEF. Methods Three databases (PubMed, Scopus, and ScienceDirect) were used to search for relevant literature published before August 6, 2024. Quality assessment was conducted using the Newcastle-Ottawa scale and its adaptation for cross-sectional studies. Statistical analysis was performed using RStudio version 4.4.1. All meta-analyses employed a random-effects model. Sensitivity analysis was conducted using the leave-one-out technique to evaluate the influence of individual studies on pooled estimates. This study protocol was registered in PROSPERO (CRD42024569609). Results A total of 5,696 HFpEF patients were identified from 28,193 individuals across 12 observational studies. GDF-15 levels were consistently elevated in HFpEF patients, with a pooled mean difference (MD) of 647.60 pg/mL (95% CI [148.43–1,146.77]; p = 0.01). Sensitivity analysis confirmed the robustness of this finding, with a slightly higher MD observed when studies involving HFpEF patients with atrial fibrillation were excluded. Qualitative analysis suggested that the overall diagnostic performance of GDF-15 in HFpEF is slightly superior to conventional biomarkers. GDF-15 showed a pooled area under the curve (AUC) of 0.82 (95% CI [0.72–0.91]), indicating good diagnostic accuracy. Additionally, GDF-15 was associated with increased risk of all-cause mortality and heart failure hospitalisation, with pooled hazard ratios (HR) of 1.46 (95% CI [1.30–1.62]; p < 0.01) and 1.76 (95% CI [1.30–2.38]; p < 0.01), respectively. Conclusion GDF-15 demonstrates significant diagnostic and prognostic potential for HFpEF. Elevated GDF-15 levels are associated with increased risk of all-cause mortality and heart failure hospitalisation.
Dakota et al. (2025) Diagnostic and prognostic implications of growth differentiation factor 15 in heart failure with preserved ejection fraction: a systematic review and meta-analysis. PeerJ 13:e20168 https://doi.org/10.7717/peerj.20168
Power analyses to inform clutch sampling design to determine the breeding sex ratio in populations with multiple paternity
In many species, demographic assessments of population viability require an estimate of the number or proportion of breeding adults in a population that are male (the breeding sex ratio). However, this estimate is often difficult to obtain directly in species with multiple paternity when males are difficult to sample. Parentage analysis of breeding females and offspring can produce this estimate by identifying the number of unique males that contribute genetic information to (i.e., sired) a given cohort. There is an added challenge of choosing a sample design with the desired level of confidence to identify all the fathers contributing to a cohort, either at the scale of individual clutches or an entire nesting season, given limited resources. Sampling effort can be defined as the number of offspring sampled per clutch, or the number of clutches sampled per breeding season, depending on the analysis. The minimum number of samples required may depend on the proportions of eggs that different fathers fertilize in a clutch (the paternal contribution mode), the total number of fathers fertilizing a clutch, the proportion of adults available for breeding that are male (the operational sex ratio), and population size. We conducted power analyses to quantify the confidence in identifying all fathers in animal populations with multiple paternity. We simulated sampling a theoretical sea turtle population with a range of population demographics, mating systems, and sampling effort, and used the proportion of 10,000 simulations in which all fathers were identified as a proxy for confidence. At the clutch level, confidence was strongly dependent on the paternal contribution mode, and when it was skewed, it also depended on the total number of fathers contributing and the number of offspring sampled. However, sampling about one third of a clutch was sufficient to identify all fathers with high confidence for most scenarios, unless the paternal contribution mode was extremely skewed and there were many contributing fathers, such that some fathers fertilized very few eggs and were difficult to detect. At the scale of an entire nesting season, confidence was more strongly affected by the operational sex ratio, the proportion of clutches sampled, and the presence or absence of polygyny than by the lesser effects of paternal contribution mode and within-clutch sample size. Sampling fewer offspring from more clutches increased confidence compared to sampling more offspring from fewer clutches. Relaxing the minimum required proportion of fathers identified from 100% to 90% led to high confidence while sampling 50% to a maximum of 75% of clutches, depending on the mating system, even as the population size increased by an order of magnitude. Our approach and results can be widely informative for sample design as well as quantifying uncertainty in existing and future estimates of the number of breeding males in populations with multiple paternity.
Quennessen et al. (2025) Power analyses to inform clutch sampling design to determine the breeding sex ratio in populations with multiple paternity. PeerJ 13:e20165 https://doi.org/10.7717/peerj.20165
Comparison of the clinical usefulness of CXCL-8 and common clinical tumor markers for esophageal cancer diagnosis
Background This study aimed to investigate serum CXC motif chemokine ligand 8 (CXCL-8) as a potential biomarker for diagnosing esophageal cancer (EC). Methods Patients diagnosed with EC (n = 141) were enrolled at the Department of Thoracic Surgery, Fujian Medical University Union Hospital, from July through December 2023. Sixty cases were early esophageal cancer (EEC), whereas 81 were advanced (AEC) based on diagnostic criteria. Healthy volunteers (n = 75) were recruited as controls. Serum CXCL-8 levels were quantified using an enzyme-linked immunosorbent assay. Levels of carcinoembryonic antigen (CEA), cytokeratin 19 fragment (Cyfra211), and squamous cell carcinoma antigen (SCC) were assessed using a chemiluminescent microparticle immunoassay. Clinical and pathological attributes of patients with EC were documented and analyzed. Diagnostic efficacies of CXCL-8, CEA, Cyfra211, and SCC for EC were evaluated using receiver operating characteristic (ROC) curves. Results Serum concentrations of CXCL-8, CEA, Cyfra211, and SCC were significantly higher in patients with EC than in controls (P < 0.05). In the EC group, areas under the curves (AUCs) for CXCL-8, CEA, Cyfra211, and SCC were 0.906, 0.707, 0.705, and 0.797, respectively. The combined application of CXCL-8+CEA, CXCL-8+Cyfra211, and CXCL-8+SCC yielded AUCs of 0.931, 0.940, and 0.950, respectively, and was significantly higher than that of the combination of CEA+Cyfra211+SCC (0.854). In EEC, the diagnostic performance of CXCL-8 was similar to that in the EC group. The sensitivity of CXCL-8 was greater than that of CEA, Cyfra211, and SCC alone, and the combination of the three markers (P < 0.05). Conclusions CXCL-8 could be used to distinguish patients with EC from healthy controls, including EEC.
Lu et al. (2025) Comparison of the clinical usefulness of CXCL-8 and common clinical tumor markers for esophageal cancer diagnosis. PeerJ 13:e20079 https://doi.org/10.7717/peerj.20079
Single-particle analysis of small extracellular vesicles from human follicular fluid unveils immunomodulatory PD-L1+ subpopulations and potentially fertility biomarkers
In certain cell systems, small extracellular vesicles bearing PD-L1 (PD-L1+ sEVs) have been shown to suppress T-cell immunity. We investigated whether a distinct profile of PD-L1+ sEVs exists in human follicular fluid (FF), a microenvironment where immune tolerance is crucial for proper follicular development. We characterized the expression and colocalization of CD63, CD81, CD9, and PD-L1 in sEVs derived from FF of women undergoing fertility treatments (n = 10), utilizing single-particle interferometric reflectance imaging sensing combined with single-particle antibody capture and immunofluorescence labeling. Additionally, sEV size distribution was analysed via atomic force microscopy. These integrated techniques revealed that the majority of tetraspanin-expressing EVs in human FF are smaller than 50 nm. Statistical analysis revealed a significant difference in PD-L1 co-expression across CD63, CD81, and CD9, confirming a preferential association of PD-L1 with CD9+ sEVs. Coefficients of variation across the cohort further indicated that PD-L1/CD9 co-expression was the most consistent among patients, suggesting a stable and distinct sEV subpopulation. These findings underscore the potential of PD-L1+ sEVs as biomarkers for immune regulation in reproductive treatments. The discovery of distinct PD-L1+ sEV subpopulations suggests a role in modulating immune responses within the follicular microenvironment. Further studies are warranted to investigate the functional relevance of these vesicles in predicting fertility outcome, promoting local immune tolerance, and facilitating follicular development.
Bortot et al. (2025) Single-particle analysis of small extracellular vesicles from human follicular fluid unveils immunomodulatory PD-L1+ subpopulations and potentially fertility biomarkers. PeerJ 13:e20057 https://doi.org/10.7717/peerj.20057
Identification of keratinocyte-associated genes for immune characterization and drug response prediction in oral squamous cell carcinoma
Background Oral squamous cell carcinoma (OSCC) is one of the most frequent types of head and neck tumor. Keratinocytes play a crucial part in tumor cell growth but their role in OSCC remains unknown. Methods We obtained single-cell RNA sequencing (scRNA-seq) data and bulk RNA sequencing data of OSCC from the Gene Expression Omnibus (GEO) database and utilized the Seurat package for quality control, downscaling, and clustering of the scRNA-seq data. The CellChat package was utilized to develop a ligand-receptor network of keratinocytes. Subsequently, high-dimensional weighted gene co-expression network analysis (hdWGCNA) and differential expression analysis were employed to identify keratinocyte-related gene modules and obtain hub genes. The predictive value of the hub genes was assessed by constructing a diagnostic model, and the CIBERSORT and ESTIMATE algorithms were utilized to analyze the correlation between immune infiltration and the diagnostic model. Finally, the mRNA expressions of the screened genes were measured, and their effects on the proliferation, migration, and invasion ability of OSCC cells were explored using in vitro models. Results We identified eight major cellular subpopulations including T cells and keratinocytes. Cellular communication revealed that keratinocytes may have close mutual communication with macrophages, fibroblasts, and endothelial cells. The hdWGCNA screening classified nine keratinocyte-related modules and 50 hub genes were extracted, among them KRT6B, KRT16, CSTB, and CSTA were identified as differentially expressed keratinocyte-related genes. A nomogram was developed, and KRT16, CSTA, and CSTB were determined as highly effective genes for the diagnosis of OSCC. Immune infiltration analysis revealed that StromalScore, ImmuneScore and ESTIMATEScore, were negatively linked to CSTA and CSTB but positively correlated with KRT16. Finally, in vitro experiments showed that the viability, migration, and invasion of OSCC cells were markedly suppressed after knockdown of KRT16. Conclusion Our study provided novel biomarkers targeting keratinocytes for the treatment of OSCC.
Huang et al. (2025) Identification of keratinocyte-associated genes for immune characterization and drug response prediction in oral squamous cell carcinoma. PeerJ 13:e19953 https://doi.org/10.7717/peerj.19953
Sniffin’ sticks smell identification test: exploring measurement properties in an adult Brazilian healthcare professionals sample
Introduction Olfactory evaluation has gained significant attention in both neurological and otorhinolaryngological assessments, particularly following the COVID-19 pandemic where SARS-CoV-2 infection emerged as a frequent cause of chemosensory dysfunction. The Sniffin’ Sticks identification test is a widely used screening tool for olfactory function. This study aimed to investigate the psychometric properties, specifically validity evidence based on internal structure (unidimensionality) and relations to other variables (demographic effects), of the 16-item Sniffin’ Sticks odor identification test (SS-16) in a homogeneous sample of highly educated young and middle-aged Brazilian adults, while exploring item-specific demographic effects. Methods A prospective observational cross-sectional study was conducted on 144 highly educated adults. The SS-16 was administered using the ‘Odor-on-lines’ paradigm. Rasch analysis assessed person-item mapping and fit statistics, while multiple regression analyses determined the effects of age, sex, and education on both overall and item-specific performance. Results Rasch analysis supported the unidimensionality of the SS-16. Item difficulty varied, with peppermint, cinnamon, and fish being easiest to identify, while apple, turpentine, and liquorice were the most challenging. Item-level analyses revealed specific demographic influences: older age was associated with poorer identification of coffee (β = −0.05, p = 0.021) and cloves (β = −0.123, p = 0.001); female sex was associated with significantly better identification of rose (β = 1.15, p = 0.026); and higher education level positively impacted identification of cloves and anise (β = 0.122, p = 0.011). These item-specific effects suggest potential differential age-related vulnerability for certain odorants, possible hormonal influences on floral odor detection, and educational effects potentially linked to semantic processing of complex aromas. Smell identification capacity was classified as “very low” (<P3, SS-16 score ≤10), “low” (≤P9, 11 points), “average” (P9.1–P84, 12–15 points), and “high” (>P84, 16 points). Conclusion This study provides insights into the psychometric properties of the SS-16 in a specific sample of Brazilian adults, demonstrating both general and item-specific demographic effects on olfactory performance. The identification of item-specific influences enhances understanding of the complex interplay between biological and sociocultural factors in olfaction. While the predominance of female participants and the homogeneous high educational profile limit broader generalizability, this analysis contributes preliminary reference data for this demographic and supports the potential utility of this culturally adapted SS-16 version for clinical screening in similar Brazilian settings. Future research requires more diverse samples to establish representative Brazilian norms.
Brandão et al. (2025) Sniffin’ sticks smell identification test: exploring measurement properties in an adult Brazilian healthcare professionals sample. PeerJ 13:e19733 https://doi.org/10.7717/peerj.19733
Retrospective study: the value of GDF-15 and conventional markers in combination for clinical diagnosis of lung cancer
Lung cancer is a leading cause of morbidity and mortality worldwide, and effective biomarkers for its screening and monitoring are still lacking. This study aims to assess the diagnostic value of Growth Differentiation Factor 15 (GDF15) in lung cancer and its subtypes, compared to conventional biomarkers, to evaluate its potential as a predictive biomarker for lung cancer screening and monitoring. GDF15 levels were measured and analyzed in different subtypes of lung cancer and non-tumor controls. The correlation between GDF15 and the expression of eight conventional biomarkers was assessed by analyzing serum GDF15 levels in the markersnormal groups and the markershigh groups. The superiority of GDF15 in screening and monitoring of lung cancer was confirmed using the receiver operating characteristic (ROC) curve analysis of GDF15, alongside conventional biomarkers. Serum GDF15 levels were significantly higher in all subtypes of lung cancer compared with non-tumor controls, showing significant correlations with the levels of conventional biomarkers. ROC curve analysis demonstrated that GDF15 has superior sensitivity and specificity over conventional biomarkers, highlighting its potential as a promising diagnostic biomarker for lung cancer. GDF15 shows strong potential as a diagnostic tool for lung cancer, outperforming conventional markers. It presents a promising new biomarker for lung cancer monitoring and diagnosis.
Ni et al. (2025) Retrospective study: the value of GDF-15 and conventional markers in combination for clinical diagnosis of lung cancer. PeerJ 13:e20281 https://doi.org/10.7717/peerj.20281
Accelerated straw decomposition and mitigated methane emissions via autumn puddling incorporation enhances soil health and yield stability in cold-region rice systems of China
This study discusses two challenges to rice production in China’s cold growing regions: the slow decomposition of straw due to low temperatures in the winter, and the environmental threats—concentrated methane emissions and soil reduction stress—associated with incorporation in the spring. To address these issues, a field experiment was conducted over two years (2022–2023) in paddy fields in central Jilin Province. The outcomes of three treatments were compared: no straw return (CK), puddling with water to promote straw incorporation in the spring (T1), and puddling with water to promote straw incorporation in the autumn (T2). The results demonstrated that T2 significantly enhanced the straw decomposition rate compared to T1 by extending the decomposition period, resulting in a 2.9% increase in straw weight loss after incorporation and a reduction in total methane emissions by 32.3%. T2 produced a smaller decline in soil redox potential, thereby alleviating soil reduction stress. Compared to CK, T2 significantly increased the levels of nitrogen, phosphorus , and calcium in the soil. T2 also maintained greater root activity and higher stem numbers than T1. While the grain yield under T2 did not differ significantly from that of CK, the yield under T1 was significantly reduced by 12.7%. Thus, incorporating puddling in autumn accelerates straw decomposition, reduces summer methane peaks, alleviates soil stress, enhances nutrient supply, and stabilizes yields. This makes it a sustainable strategy for managing straw in cold-region rice systems.
He et al. (2025) Accelerated straw decomposition and mitigated methane emissions via autumn puddling incorporation enhances soil health and yield stability in cold-region rice systems of China. PeerJ 13:e20264 https://doi.org/10.7717/peerj.20264
Lower limb joints’ contributions to ballet turnout during unipodal and bipodal jumps in fifth position in pre-professional dancers
Turnout, a large external rotation of the lower limb joints, is a key element of jumps and of other postures in classical ballet technique. Correct transverse-plane alignment of body segments in turnout is critical to reduce technical errors and injury risk. Although many studies have examined turnout in static positions, there is a need for a deeper understanding of this element dynamically, particularly during uni- and bipodal jumps with body displacements in fifth position. Such insights could help improve the technique and the training protocols. This study investigated the external rotations of the hip, knee, and ankle in turnout during three phases (preparation, flight, and landing) of two jumps with displacement performed in the fifth position: one unipodal, the Sissone Ouvert, and one bipodal, the Assemblé Dessus. Twenty-eight pre-professional ballet dancers were analyzed with 10.9 ± 3.2 years of ballet practice, 12.4 ± 2.7 hours of weekly training and a passive hip external rotation (static turnout) of 53.9 ± 10.1 deg. The dancers were instrumented with 16 skin-markers according to the Plug-in-Gait protocol and an eight-camera motion analysis system recorded lower limb kinematics in the transverse plane of the self-selected leg. Temporal profiles of joint angles were time normalized and the external rotation peak of hip, ankle, and knee were compared across phases and joints by repeated measures analysis of variance (ANOVAs) and Newman–Keuls post hoc (p < 0.05). The external rotation peak of the ankle, knee, and hip differed across phases (p < 0.001) for both jumps. In the Assemblé, hip and knee rotation peaks exhibited a similar behavior between the preparation and flight, while the ankle reached its highest peak at landing (p = 0.022). In the Sissone’s preparation, knee and ankle peaks showed significantly greater rotation compared to hip (p < 0.001), whereas in the flight, the hip exhibited the highest rotation compared to the other joints (p < 0.001). The external rotation peak occurred in different instants in each phase and with respect to normalized jump duration (p < 0.001). In conclusion, the knee joint has little contribution to external rotations in the turnout; conversely, the ankle and the hip joints appear to be pivotal in maintaining the turnout respectively in the Assemblé and in the Sissone, the latter mainly during the flight phase.
Manfrim et al. (2025) Lower limb joints’ contributions to ballet turnout during unipodal and bipodal jumps in fifth position in pre-professional dancers. PeerJ 13:e20263 https://doi.org/10.7717/peerj.20263