title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=2 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Elucidating the invasion history of introduced bullfrogs in New Mexico using population genetic approaches link: https://peerj.com/articles/20491 last-modified: 2026-01-09 description: The American Bullfrog, Rana (Aquarana) catesbeiana, is an extremely successful invader that has spread globally in the last century, impacting vulnerable ecosystems. In the western U.S., bullfrogs were intentionally introduced in the early 1900s, but little is known about their subsequent colonization into the state of New Mexico. We evaluated a single mitochondrial gene region, cytochrome b, using population genetic approaches to investigate the invasion history of bullfrogs across their introduced range. Specifically, our objectives were to (1) assess the level of genetic diversity and identify haplotypes within bullfrog populations in New Mexico, (2) compare the genetic diversity of native and invasive bullfrog populations, (3) infer the number of introductions into New Mexico, and (4) identify potential native source populations. Using haplotype and nucleotide diversity estimates, we found moderate genetic variation within New Mexico (Hd = 0.648, π = 0.0036) with higher diversity at sites with increased human activity. However, there was significantly lower genetic diversity in introduced populations compared to native populations, consistent with expectations of recent colonization. Based on haplotype diversity estimates and BLAST results, we found a total of eight haplotypes across New Mexico, of which six haplotypes were found across the native and other introduced ranges. Pairwise ΦST revealed minimal differentiation between New Mexico sites, consistent with introduction from a single source population. Lastly, the analysis of molecular variance (AMOVA) conveyed that bullfrogs from the Northwest (Northwest: 0%, P = 0.6411) and Southwest (Southwest: 0%, P = 0.5124) invasive regions showed no significant differences compared to New Mexico populations, suggesting either recent connectivity or similar origins. This study reinforces the importance of managing the movement of invasive species and demonstrates how evaluating the genetic composition of an invasive species can reveal key points of its invasion history. creator: Celina M. Eberle creator: Daniele L.F. Wiley creator: Chris X. McDaniels creator: J. Tomasz Giermakowski creator: Lisa N. Barrow uri: https://doi.org/10.7717/peerj.20491 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Eberle et al. title: Endophytic fungi and their secondary metabolites in Qin medicine plants: a comprehensive review of diversity, function, and application link: https://peerj.com/articles/20487 last-modified: 2026-01-09 description: Qin medicine represents the premier local traditional Chinese medicinal herbs in Shaanxi province (China) and its neighboring areas. Endophytic fungi, an essential element of the internal ecosystem of medicinal plants, have attracted considerable attention for their roles in enhancing plant resistance to pests and diseases, increasing the concentration of bioactive compounds, and stimulating plant growth and development. This paper presents the first comprehensive review of endophytic fungi in Qin medicinal plants, summarizing their diversity, effects on plant growth and medicinal quality, as well as novelty and bioactivity of their secondary metabolites. It also highlights their potential applications in promoting plant growth. Furthermore, this study explores the current opportunities and challenges in the research of endophytic fungi within Qin medicinal plants, with the objective of offering a unique perspective for the advancement and development of Qin medicinal plants. creator: Bo-Yang Chen creator: Tong Li creator: Wen-Pu Shi creator: Juan-Juan Yang creator: Yang Bai creator: Qi-Meng Xue creator: Chen-Li Jiao creator: Pei-Feng Wei creator: Liang-Liang Chen uri: https://doi.org/10.7717/peerj.20487 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Chen et al. title: A highly diverse Pennsylvanian tetrapod ichnoassemblage from the Semily Formation (Krkonoše Piedmont Basin, Czechia) link: https://peerj.com/articles/20437 last-modified: 2026-01-09 description: The Krkonoše Piedmont Basin (KPB) is one of the Late Paleozoic continental basins in Bohemia, Czechia, comprising a sedimentary sequence from the Late Pennsylvanian to the early Cisuralian. The Pennsylvanian in the KPB consists of alluvial-fluvial to lacustrine deposits with a relatively rich fossil record, comprising mainly ray-finned fishes, freshwater sharks, and invertebrates. Although no skeletal remains of terrestrial vertebrates have been discovered in the Late Pennsylvanian deposits of the KPB, recent studies of tetrapod footprints provide the first direct evidence of pre-Permian terrestrial tetrapod diversity within this basin. A diverse ichnofossil assemblage is represented by six ichnogenera, Amphisauropus, Batrachichnus, Dimetropus, Dromopus, Ichniotherium and Limnopus, including five known ichnospecies, Amphisauropus kablikae, Batrachichnus salamandroides, Dromopus lacertoides, Ichniotherium cottae, and Limnopus heterodactylus, and two unknown ichnospecies, Dimetropus isp. and Limnopus isp. This tetrapod ichnoassemblage is among the most diverse in the Pennsylvanian. Moreover, the Amphisauropus tracks from the KPB represent the first undisputed occurrence of this ichnotaxon in the Gzhelian. Furthermore, the Ichniotherium cottae tracks described here complement the still rare Pennsylvanian occurrences of this ichnospecies in the European part of Pangaea. The ichnofauna studied herein is associated with alluvial-plain to lacustrine nearshore deposits, highlighting the ecological importance of the lacustrine environment and its adjacent areas for the presence of terrestrial vertebrates and the preservation of their footprints. creator: Gabriela Calábková creator: Jakub Březina creator: Roland Nádaskay uri: https://doi.org/10.7717/peerj.20437 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Calábková et al. title: Abundance in secret: a review of the genus Leptobrachium (Anura, Megophryidae) in India, with descriptions of two new species link: https://peerj.com/articles/20397 last-modified: 2026-01-09 description: Of the 39 currently recognized species in the Slender Armed Frog genus Leptobrachium, four are reported from India, Leptobrachium aryatium, L. bompu, L. smithi, and L. sylheticum. Based on new collections, we review these reported species by integrating molecular, morphological, and behavioral data. Our comparative analyses of external and internal morphology as well as molecular data and acoustic properties reveal two new species-level lineages from the Lower Dibang Valley and Shi Yomi districts of Arunachal Pradesh, India, which we describe here as new species. Phylogenetically, Leptobrachium mechukasp. nov. and Leptobrachium somanisp. nov. are members of the L. bompu species group, but they are distinct from L. bompu sensu stricto by DNA sequence divergence in the 16S mitochondrial rRNA gene of 3.6–4.2% and 4.5–4.7%, respectively. A population previously identified as L. cf. bompu from Medog County, China, is also assignable to Leptobrachium mechukasp. nov. Each new species is distinguished from congeners by a combination of diagnostic morphological characters, including in the case of Leptobrachium somanisp. nov., a unique advertisement call comprising two distinct call types; unicolored silvery white iris; moderately large webbing between toes; and ventral coloration. Leptobrachium mechukasp. nov. on the other hand, is distinguishable by its head length equal to width; nostril equidistant from the snout tip and the eye; internarial distance equal to the distances from nostril to eye and from nostril to snout tip; distance from the tip of inner metatarsal tubercle to the tip of first toe shorter than the length of inner metatarsal tubercle itself; and frontoparietals separated at the midline by a moderate fontanelle. Analyses of multiple new populations representing members of the L. smithi group reveal that L. smithi is absent from the Indian fauna; all previous records attributed to this species from India instead represent L. aryatium or L. sylheticum. These discoveries highlight the prevalence of taxonomic misidentifications in the absence of detailed systematic studies as well as the underestimation of diversity in the genus Leptobrachium, not only from India but across its known range. Our results underscore the need for dedicated surveys that document amphibian diversity in underexplored regions of Northeast India. creator: A.N. Dikshit Akalabya Sarmah creator: Sonali Garg creator: Tage Tajo creator: Radhakrishna Upadhyaya K. creator: James Hanken creator: S.D. Biju uri: https://doi.org/10.7717/peerj.20397 license: https://creativecommons.org/licenses/by-nc/4.0 rights: ©2026 Sarmah et al. title: Fungal-specific IgG responses in allergic conjunctivitis: comparison with IgE and immunological implications link: https://peerj.com/articles/20625 last-modified: 2026-01-08 description: BackgroundImmunoglobulin G (IgG) is the most abundant antibody class in the bloodstream and is characterized by a long half-life compared to other immunoglobulins. While IgG plays a key role in host defense against infections, it is also known to be elevated in chronic inflammatory conditions. This study aimed to evaluate serum levels of fungus-specific Immunoglobulin E (IgE) and IgG antibodies in patients with allergic conjunctivitis and to investigate their associations with disease severity and sensitization status.MethodsA total of 40 patients with allergic conjunctivitis and 20 healthy controls were enrolled. Serum levels of specific IgE and IgG antibodies against four common fungi—Alternaria, Aspergillus, Cladosporium, and Penicillium—were measured. These values were compared with skin prick test (SPT) results and clinical severity scores for allergic conjunctivitis (0–30 scale).ResultsPatients with allergic conjunctivitis exhibited significantly higher positivity rates and serum titers of both IgE and IgG against all four fungal antigens compared to controls (p < 0.05). Notably, IgG titers were significantly higher than IgE titers across all fungal antigens (p < 0.05). IgG levels demonstrated stronger correlations with SPT positivity (correlation coefficients r = 0.95–0.97 vs. r = 0.60–0.89 for IgE) and allergic conjunctivitis severity scores (r = 0.35–0.60 vs. r = 0.23–0.43 for IgE, p < 0.001).ConclusionsSerum fungus-specific IgG antibodies may serve as useful biomarkers reflecting the severity of allergic conjunctivitis. Given that mucosal barrier dysfunction has been implicated in allergic inflammation, the findings suggest that hypersensitivity reactions to fungal elements due to impaired barrier function may contribute to disease pathogenesis. creator: Tatsuya Mimura uri: https://doi.org/10.7717/peerj.20625 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Mimura title: Effect of acute exercise on the dynamics of testosterone levels: a systematic review of randomized controlled trials link: https://peerj.com/articles/20615 last-modified: 2026-01-08 description: PurposeAlthough acute exercise has been demonstrated to modulate endogenous testosterone levels, existing studies have reached conflicting conclusions regarding the pattern of response of testosterone levels after exercise. The objective of this study was to examine the dynamic effects of acute exercise on testosterone levels and to analyze the differences in the role of factors such as exercise mode, intensity, sample source, and gender.MethodsA comprehensive search of articles published up to March 2025 was conducted in five database systems, including PubMed and Web of Science, in accordance with the PRISMA guidelines. A total of 15 randomized controlled trials assessing the effect of acute exercise on testosterone levels were included, with a total sample size of 251 participants.Results(1) Testosterone levels demonstrate a greater increase following resistance training, with a delayed return to baseline levels; in contrast, testosterone levels typically recover within 1 h after aerobic exercise. (2) Moderate to high-intensity exercise stimulates the hypothalamic-pituitary-gonadal axis (HPG), leading to a transient rise in testosterone, but extended high-intensity exercise causes testosterone suppression during recovery due to cortisol antagonism for up to 72 h. The testosterone concentration during the active phase exceeds that during the recovery period. (3) A significant disparity in baseline testosterone levels exists between males and females, with males exhibiting higher levels. Additionally, males demonstrate a more pronounced response to exercise compared to females. (4) Blood tests exhibit greater sensitivity than saliva tests, although the latter is more reactive to high-intensity exercise; (5) The response is more pronounced in younger males compared to older adults, with negligible response observed in adolescents.ConclusionVariations in testosterone level modulation due to acute exercise are predominantly influenced by exercise mode, intensity, sample source, and subject characteristics (gender and age). While resistance training and high-intensity exercise might temporarily increase testosterone levels, it is essential to consider the potential for hormonal imbalance after recovery; age and sex variations, along with assay standardization, are critical areas for further investigation. This review was registered PROSPERO with registration number CRD420251007222. creator: Qianxin Tu creator: Gen Li creator: Songtao Wang uri: https://doi.org/10.7717/peerj.20615 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2026 Tu et al. title: Characterizing core muscle morphometry in postpartum women with pelvic girdle pain and asymptomatic subjects: a comparative cross-sectional study link: https://peerj.com/articles/20601 last-modified: 2026-01-08 description: BackgroundThis study aimed to examine the differences in core muscle morphometry and contraction changes between postpartum individuals with and without pelvic girdle pain (PGP). Understanding the observed changes in muscle thickness and contraction characteristics is crucial for tailoring effective core muscle rehabilitation strategies that promote optimal postpartum recovery.MethodsA cross-sectional study was conducted involving 150 postpartum women with PGP and 50 asymptomatic individuals as matched controls. Real-time musculoskeletal ultrasound was used to measure core muscle morphometry and assess changes in muscle thickness and percentage change during various tasks.ResultsCompared with asymptomatic women, individuals with PGP exhibited substantially reduced diaphragm excursion and thinner muscle thickness of the transverse abdominal muscle (TrA) during active straight leg raise (ASLR) tests with abdominal muscle contractions (P < 0.05). The TrA respiratory contraction rate and preferential activation ratio during abdominal breathing were also lower in the PGP group (PGP = 0.46 (0.13 to 1.41); asymptomatic women = 0.98 (0.05 to 2.05), P = 0.01). In addition, postpartum women with PGP showed increased activation of the internal oblique muscle during ASLR tests with abdominal muscle contractions compared to controls (PGP: 47%; asymptomatic women: 45%, P < 0.05). Furthermore, the bilateral lumbar multifidus muscle was smaller and thinner on the right side in the PGP group than the asymptomatic group (P < 0.001).ConclusionPostpartum women with PGP exhibited thinner muscle thickness on core muscle morphometry and less muscle change during abdominal breathing and the ASLR test. creator: Ziling Lin creator: Bo Chen creator: Ruoling Chen creator: Xueling Chen creator: Yanjun Hou creator: Yanping Liu creator: Lili Lin creator: Zhiwei Lin creator: Xiangbin Wang creator: Cheng Zeng uri: https://doi.org/10.7717/peerj.20601 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Lin et al. title: Non-targeted metabolomic profiling of Cremastra appendiculata providing insights for phytochemical analyses link: https://peerj.com/articles/20592 last-modified: 2026-01-08 description: BackgroundCremastra appendiculata (D. Don) Makino, known as “Shan Cigu” in China, is a valuable medicinal plant historically employed for its antibacterial and anti-inflammatory properties. However, its comprehensive metabolome remains underexplored, hindering the establishment of standardized quality control.MethodsIn this study, a non-targeted metabolomics approach based on the Thermo Fisher Orbitrap Exploris 120 LC-MS (Liquid Chromatography-Mass Spectrometry) platform was employed to systematically profile the metabolites of C. appendiculata.ResultsA total of 174 compounds were annotated through a dual-validation workflow integrating Compound Discoverer 3.3 and manual tandem mass spectrometry spectral verification. Orthogonal partial least squares discriminant analysis prioritized 30 candidate quality markers, of which, six were further validated through network pharmacology-based bioactivity screening. Hierarchical clustering analysis revealed distinct metabolic patterns across the different tissues (roots, pseudobulbs, and leaves), establishing a tissue-specific chemical atlas. The integration of chemometric, network pharmacological, and chemotaxonomic analyses resulted in a robust, molecularly guided quality control framework, providing novel insights for phytochemical research and medical applications of C. appendiculata. creator: Rui Guan creator: Yuxin Shan creator: Hamizah Shahirah Hamezah creator: Somnuk Bunsupa creator: Hong To Quyen Duong creator: Yadong Zhou creator: Rongchun Han creator: Xiaohui Tong uri: https://doi.org/10.7717/peerj.20592 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Guan et al. title: Analysis of clinical parameters of different types of α-thalassemia children in Hainan region, China link: https://peerj.com/articles/20586 last-modified: 2026-01-08 description: BackgroundThalassemia, a hereditary hemoglobinopathy characterized by impaired hemoglobin production, results in the premature destruction of erythrocytes and consequent anemia. However, the distinct hematological parameters and phenotypic expressions associated with different α-thalassemia genotypes in the pediatric population remain inadequately characterized. Therefore, this study was designed to perform a comparative analysis of clinical parameters between pediatric patients with α-thalassemia and healthy controls, to elucidate genotype-specific disease manifestations, and to inform optimized management strategies.MethodsThis retrospective cross-sectional study enrolled 160 children with genetically confirmed α-thalassemia and 105 healthy controls in Hainan. Participants were categorized into silent carrier, mild, Hb H disease, and control groups. Comprehensive assessments included hematological parameters, biochemical profiles, coagulation function, growth Z-scores, and serum ferritin. Group comparisons were performed across genotypes and age strata (1–5, 6–11, 12–18 years) using appropriate statistical methods.ResultsChildren diagnosed with Hb H disease exhibited the most severe hematological impairments, including growth retardation, elevated bilirubin levels, increased ferritin concentrations, and altered coagulation parameters. Among the genotypes studied, non-deletional types (--SEA/αQSα, --SEA/αCSα) demonstrated the most pronounced deficits. Growth Z-scores, encompassing weight-for-age (WAZ), height-for-age (HAZ), and body mass index-for-age (BAZ), were significantly reduced in the Hb H disease cohort, with deterioration observed as age increased. Notably, even silent carriers of the disease exhibited developmental delays during later childhood. Furthermore, iron overload and subclinical organ involvement were evident in older children affected by Hb H disease.ConclusionsThe clinical phenotype of pediatric α-thalassemia is significantly influenced by both genotype and age, with non-deletional Hb H disease presenting the highest risk for systemic complications. These findings emphasize the necessity for genotype-specific monitoring, early nutritional and iron-chelation interventions, and a multidisciplinary follow-up approach to enhance long-term outcomes. creator: Ge Gao creator: Zhengnan Sun creator: Junhong Chen creator: Jinyu Kang creator: Fei Sun creator: Qi Li creator: Limei Fu creator: Yi Gong creator: Linna Ma creator: Qiuling Jie creator: Yanlin Ma uri: https://doi.org/10.7717/peerj.20586 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Gao et al. title: Species diversity patterns in Tagetes minuta-invaded plant communities along an elevational gradient in Southeastern Xizang link: https://peerj.com/articles/20573 last-modified: 2026-01-08 description: Tagetes minuta, a herbaceous plant native to South America, has shown a significant trend of invasion along the section from Nyingchi to Shannan, situated along the Yarlung Zangbo River in southeastern Xizang in recent years. In this study, we conducted field surveys of T. minuta plant communities at elevations ranging from 2,925 to 3,553 m. By establishing 31 quadrats, we systematically analyzed the species composition, diversity characteristics of the invaded communities of T. minuta, and their relationships with elevation gradients and habitat types. The study results revealed that a total of 78 plant species, belonging to 28 families and 69 genera, were recorded in the T. minuta-invaded plant communities. Among them, the families Asteraceae, Poaceae, and Rosaceae were dominant, with herbaceous plants being in an absolute majority. The diversity analysis showed that the Shannon–Wiener index, Simpson index, and Pielou’s evenness index of were significantly higher in the community group mainly composed of Eragrotis pilosa and Plantago depressa (Cluster Group II) compared to the groups dominated by Poa annua plus Plantago depressa (Cluster Group I) and Poa annua and Digitaria cruciata (Cluster group III) (P < 0.05), while no significant differences were found in species richness. This suggests that the invasion of T. minuta primarily affects the evenness of species distribution rather than species richness. In addition, the species diversity indices of the T. minuta-invaded plant communities showed no significant correlation with elevation, indicating that elevation is not a major factor influencing species diversity in the invaded communities. The height of T. minuta was significantly positively correlated with elevation (P < 0.01), while its cover showed no significant correlation with elevation. Under different habitat types, the height and cover of T. minuta showed significant differences, with stronger invasion ability in habitats with greater human disturbance. This study highlights the invasion characteristics of T. minuta and its relationship with elevation in southeastern Xizang, offering valuable data for the ecological management of invasive plant species in plateau regions. creator: Norzin Tso creator: Ngawang Norbu creator: Wei Li creator: Xin Tan creator: Zhefei Zeng creator: La Qiong creator: Junwei Wang uri: https://doi.org/10.7717/peerj.20573 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2026 Tso et al.