Search Results (390)

Cryptic species are morphologically indistinguishable but possess genetically distinct taxa. Alternative splicing (AS) regulates physiological processes, thereby facilitating ecological adaptation and evolution. To explore the sex-specific differences in transcriptional regulation among cryptic species, we profiled both AS and gene expression in two cryptic species of Wiebesia pumilae (WPDZ19 and WPHS), which differ in Wolbachia infection status. The results showed that 101 and 71 differentially alternatively spliced genes (DASs) were identified in female and male groups, respectively. Functional enrichment revealed that female DASs were significantly enriched in mitotic cell cycle process, cytoskeleton organization, cellular component organization, and DNA damage. On the other hand, male DASs were predominantly related to actin, cytoskeleton, and muscle development. Gene set enrichment analysis of DASs also revealed that the regulation of mitotic nuclear division and meiotic nuclear division were enriched in female and male groups, respectively. We identified 4509 DEGs in females and 3645 in males, with minimal overlap between DASs and DEGs. Moreover, RT-PCR has been used to validate the key genes. Our results revealed sexually divergent transcriptional regulation patterns between WPDZ19 and WPHS, suggesting a potential association with Wolbachia persistence. Our findings provide new insights into the study of adaptive evolution of cryptic species. Full article

Background/Objectives: Morphological defects such as limb malformations, cranial asymmetries, loin deviations, jaw misalignments, and navel irregularities are associated with early culling and reduced productivity in beef cattle. In Bos taurus indicus such as Nellore, the genetic basis of these traits remains poorly characterized. This study aimed to investigate the genetic architecture of six morphological defects in Nellore cattle, namely feet and legs malformation, chamfer asymmetry, fallen hump, loin deviation, jaw misalignment, and navel irregularities, via a genome-wide association study (GWAS) approach tailored for binary traits. Methods: Depending on the trait, the number of genotyped animals analyzed ranged from 3369 to 23,206, using 385,079 SNPs (after quality control). Analyses were conducted using a linear mixed model framework adapted for binary outcomes. Results: Significant associations were identified for four traits: feet and legs, chamfer, hump, and loin. No significant markers were detected for jaw or navel defects, likely due to lower sample sizes and trait incidence. Gene annotation revealed 49 candidate genes related to feet and legs, 4 for chamfer, 4 for hump, and 6 for loin. Conclusions: Candidate genes were enriched for biological functions, including bone remodeling, muscle development, lipid metabolism, and epithelial organization. Overlaps with QTL related to conformation, feed intake, reproductive traits, and carcass quality were also observed. These findings provide novel insights into the genetic control of morphological defects in Nellore cattle and may inform breeding strategies aimed at improving structural soundness. Full article

The mammalian skull, which surrounds and protects the brain, is one of the most morphologically diverse and functionally important structures in the vertebrate body. As one of the most ecologically diverse mammals, the developmental dynamics of morphological and structural changes and functional diversity in the skull of bats need to be revealed. Here, we focused on the developmental characteristics of the Vespertilio sinensis skull, and used statistical analysis, spatial morphology visualization, and comparative analysis of the Stretch Factors (SF) of the masticatory muscles to better understand the connection between the morphology of the skull and the development of the body size during the developmental process of V. sinensis, the changes in the three-dimensional (3D) spatial morphology and structure, and the correlations between opening capacity and the transformation of feeding habits. This study not only provides a new perspective for understanding the morphological adaptive mechanism of ecological niche expansion that accompanies the transition of mammalian skulls from juvenile to adult feeding but also provides a crucial scientific basis for an in-depth understanding of the growth and developmental mechanism of bats’ skull and even vertebrates as a whole, which is potentially useful for the development of ecological conservation and evolutionary biology. Full article

Background: This study investigated sex differences in foot arch structure and function, and their impact on postural control and energy flow during dynamic tasks. Findings aim to inform sex-specific training, movement assessment, and injury prevention strategies. Methods: A total of 108 participants (53 males and 55 females) underwent foot arch morphological assessments and performed a sit-to-stand (STS). Motion data were collected using an infrared motion capture system, three-dimensional force plates, and wireless surface electromyography. A rigid body model was constructed in Visual3D, and joint forces, segmental angular and linear velocities, center of pressure (COP), and center of mass (COM) were calculated using MATLAB. Segmental net energy was integrated to determine energy flow across different phases of the STS. Results: Arch stiffness was significantly higher in males. In terms of postural control, males exhibited significantly lower mediolateral COP frequency and anteroposterior COM peak velocity during the pre-seat-off phase, and lower COM displacement, peak velocity, and sample entropy during the post-seat-off phase compared to females. Conversely, males showed higher anteroposterior COM velocity before seat-off, and greater anteroposterior and vertical momentum after seat-off (p < 0.05). Regarding energy flow, males exhibited higher thigh muscle power, segmental net power during both phases, and greater shank joint power before seat-off. In contrast, females showed higher thigh joint power before seat-off and greater shank joint power after seat-off (p < 0.05). Conclusions: Significant sex differences in foot arch function influence postural control and energy transfer during STS. Compared to males, females rely on more frequent postural adjustments to compensate for lower arch stiffness, which may increase mechanical loading on the knee and ankle and elevate injury risk. Full article

β-Hydroxy-β-methylbutyrate (HMB), a natural metabolite derived from the essential amino acid leucine, is primarily recognised for its anabolic and anti-catabolic effects on skeletal muscle tissue. Recent studies indicate that HMB may also play a role in influencing the structural organisation of extracellular matrix (ECM) components, particularly collagen, which is crucial for maintaining the mechanical integrity of connective tissues. In this investigation, bovine type I collagen was polymerised in the presence of two concentrations of HMB (0.025 M and 0.25 M) to explore its potential function as a molecular modulator of fibrillogenesis. The morphology of the resulting collagen fibres and their molecular architecture were examined using atomic force microscopy (AFM) and Fourier-transform infrared (FTIR) spectroscopy. The findings demonstrated that lower levels of HMB facilitated the formation of more regular and well-organised fibrillar structures, exhibiting increased D-band periodicity and enhanced stabilisation of the native collagen triple helix, as indicated by Amide I and III band profiles. Conversely, higher concentrations of HMB led to significant disruption of fibril morphology and alterations in secondary structure, suggesting that HMB interferes with the self-assembly of collagen monomers. These structural changes are consistent with a non-covalent influence on interchain interactions and fibril organisation, to which hydrogen bonding and short-range electrostatics may contribute. Collectively, the results highlight the potential of HMB as a small-molecule regulator for soft-tissue matrix engineering, extending its consideration beyond metabolic supplementation towards controllable, materials-oriented modulation of ECM structure. Full article

Background and Objectives: The lateral pterygoid muscle (LPM) is typically described as a two-headed muscle within the infratemporal fossa. However, cadaveric and imaging studies have revealed substantial variability in the number of heads, insertion patterns, and relations to neurovascular structures. Materials and Methods: An observational study of 250 brain computed tomography angiographies (CTAs) was performed to assess LPM morphology. Additionally, a systematic review and meta-analysis were conducted in accordance with PRISMA 2020 and Evidence-based Anatomy guidelines. Pooled prevalence estimates were calculated with random-effects models. Results: The current study included 250 CTAs for the original study and 1702 muscles for the meta-analytic evidence. During the original study, the two-headed configuration was most common (74.4%), followed by three-headed (14%), one-headed (10.8%), and four-headed (0.8%) morphologies. Symmetry was observed in 75.2% of patients. Meta-analysis confirmed the predominance of the two-headed type (73.98%, 95% CI: 68.22–79.38), with three-headed (16.82%), one-headed (4.37%), and four-headed (<0.01%) variants occurring less frequently. Subgroup analyses showed no significant differences by study type or sample size, though European populations exhibited a higher prevalence of one-headed forms. Conclusions: The LPM demonstrates considerable morphological variability, extending beyond the traditional two-headed model. Recognition of these variants is essential for understanding temporomandibular joint function, interpreting imaging, and planning surgical or interventional procedures within the infratemporal fossa. Advanced imaging provides a reliable tool for individualized anatomical assessment, supporting safer clinical practice. Full article

Background: Chronic neck pain (CNP) is considered a widespread musculoskeletal condition which affects the quality of life and is associated with scapular stabilizer dysfunction patterns. This study aimed to compare the morphological, functional, and strength-related characteristics of the lower trapezius muscle (such as muscle thickness at rest and during contraction, contraction-to-relaxation ratios, contraction and relaxation velocities, and force production) between individuals with CNP and asymptomatic controls. Methods: This cross-sectional study comprises 144 participants (78 with CNP and 76 controls) aged 18–30 years. Ultrasound imaging was used to assess muscle thickness, contraction and relaxation velocities, and contraction ratios. Muscle strength, including peak force and rate of force development, was evaluated using dynamometry. Participants with CNP were categorized by neck disability index (NDI) scores into mild, moderate, and severe groups. Results: Participants with CNP showed reduced contraction velocity (0.60 ± 0.24 cm/s vs. 0.81 ± 0.44 cm/s; p < 0.001; d = 0.61), lower relaxation velocity (0.48 ± 0.28 cm/s vs. 0.58 ± 0.32 cm/s; p = 0.038; d = 0.34), and decreased peak force (4.83 ± 3.27 kg vs. 6.00 ± 3.87 kg; p = 0.043; d = 0.33) compared to controls. Muscle thickness and contraction ratio differences were non-significant. Among CNP subgroups, the contraction ratio was lower in the severe disability group compared to the mild group (0.25 ± 0.19 vs. 0.53 ± 0.33; p = 0.015). Conclusions: The present study showed functional impairments of the lower trapezius muscle in individuals with CNP, particularly reduced contraction and relaxation velocities and lower peak force, with more pronounced deficits in those with severe disability. While no significant differences in muscle thickness were found, these findings suggest that functional alterations may precede structural changes. Full article

Skeletal muscle, constituting 40–50% of total body mass, is vital for mobility, posture, and systemic homeostasis. Muscle contraction heavily relies on ATP, primarily generated by mitochondrial oxidative phosphorylation. Mitochondria play a key role in decoding intracellular calcium signals. The endocannabinoid system (ECS), including CB₁ receptors (CB₁Rs), broadly influences physiological processes and, in muscles, regulates functions like energy metabolism, development, and repair. While plasma membrane CB₁Rs (pCB₁Rs) are well-established, a distinct mitochondrial CB₁R (mtCB₁R) population also exists in muscles, influencing mitochondrial oxidative activity and quality control. We investigated the role of mtCB₁Rs in skeletal muscle physiology using a novel systemic mitochondrial CB₁ deletion murine model. Our in vivo studies showed no changes in motor function, coordination, or grip strength in mtCB₁ knockout mice. However, in vitro force measurements revealed significantly reduced specific force in both fast-twitch (EDL) and slow-twitch (SOL) muscles following mtCB₁R ablation. Interestingly, knockout EDL muscles exhibited hypertrophy, suggesting a compensatory response to reduced force quality. Electron microscopy revealed significant mitochondrial morphological abnormalities, including enlargement and irregular shapes, correlating with these functional deficits. High-resolution respirometry further demonstrated impaired mitochondrial respiration, with reduced oxidative phosphorylation and electron transport system capacities in knockout mitochondria. Crucially, mitochondrial membrane potential dissipated faster in mtCB₁ knockout muscle fibers, whilst mitochondrial calcium levels were higher at rest. These findings collectively establish that mtCB₁Rs are critical for maintaining mitochondrial health and function, directly impacting muscle energy production and contractile performance. Our results provide new insights into ECS-mediated regulation of skeletal muscle function and open therapeutic opportunities for muscle disorders and aging. Full article

Background: Muscle health is an emerging concept linked to physical performance and functional independence. However, the term lacks a standardized definition and is often used as a broad muscle-related outcome descriptor. Clinical communication and research would benefit from a conceptual model of muscle health grounded in an established framework. Methods: We conducted systematic search and narrative synthesis to identify multifactorial measurement approaches explicitly described under ‘muscle health’. PubMed and CINAHL were searched for clinical and randomized controlled trials published in the past 5 years (final search: March 2025) that used the term “muscle health.” Studies were reviewed for explicit definitions of “muscle health,” and all identified outcomes (e.g., strength, mass) and measurement tools (e.g., grip strength, ultrasound) were synthesized. This review was retrospectively registered (INPLASY202580069). Results: Of the 65 clinical or randomized controlled trials that met inclusion criteria, 29 provided an operational definition of ‘muscle health’, while 36 inferred measurements without a clear definition. The identified measurements spanned four primary categories, with body composition/muscle mass being the most common (92.3%), followed by muscle performance (78.5%), physical function (63.1%), and tissue composition (30.8%). Most studies included more than one muscle health metric (93.9%). Common assessment methods included DXA (44.6%), grip strength (64.6%), and gait speed (27.7%). Conclusions: While there are common measurement approaches, the definition of muscle health varies widely in the cited works. The framework of the International Classification of Functioning, Disability and Health, was used to identify domains aligned with muscle health components of muscle morphology/morphometry (e.g., mass and composition), functional status (performance-based tasks), and physical capacity (muscle performance). This framework provides a structured basis for evaluating muscle health in research and clinical practice. Consistent use of these domains could enhance assessment and support efforts to standardize testing and interpretation across settings. Full article

The parturition season of grazing Tibetan ewes spans from October to March, a period that exacerbates the adverse impacts of nutrient-deficient herbage on milk yield, body condition, and postpartum recovery. To alleviate the weight loss of ewes during the cold seasons, we provided concentrate supplements at four levels (dry matter (DM) basis), 260 g (C1), 440 g (C2), 520 g (C3), and 610 g (C4), alongside a basal diet of grazed pasture. A total of 96 multiparous Tibetan ewes (third parity, body weight: 45.17 ± 3.69 kg (body weight (BW) were enrolled within 12–18 h postpartum and randomly allocated to four dietary groups (n = 24 ewes per group). We measured growth performance, ruminal histomorphology, fermentation parameters, and digestive enzymes. A multi-omics technique (16S rRNA gene sequencing and RNA-seq) was employed to investigate the mechanisms underlying alterations in ruminal function. The results showed that increasing the concentrate level decreased body weight loss and increased average dry matter intake (p < 0.05). Rumen morphology was significantly altered: papilla width and muscle layer thickness were greatest in the C4 group, whereas submucosal thickness was highest in the C1 group (p < 0.05). Cellulase activity was lowest in the C1 group (p < 0.05). Papilla width of lactating Tibetan ewes in the C4 group was higher (p < 0.05) than that in the C1 and C3 groups. Concentrate supplementation altered ruminal microbiota composition and diversity. Each group exhibited a distinct microbial signature: the C1 group was characterized by Lachnospiraceae_XPB1014_group, Candidatus_Omnitrophus, Paenibacillus, and unclassified_Oligoflexaceae; the C2 group was enriched in Papillibacter, Anaerovibrio, V9D2013_group, and unclassified_Peptococcaceae; the C3 group was characterized by unclassified_Bacteroidales_RF16_group; and the C4 group was characterized by Ruminococcus, Pseudobutyrivibrio, and Mitsuokella (p < 0.05). Transcriptomic analysis identified differentially expressed genes (TRPA1, EPHB1, GATA3, C4, ABCG2, THBS4, and TNFRSF11B) that are predominantly involved in immune regulation, signal transduction, and nutrient digestion. The results of Spearman correlation analysis showed that Anaerovibrio was negatively correlated with propionate (r = −0.565, p < 0.05). However, it was positively correlated with the ratio of acetate and propionate (r = 0.579, p < 0.05). Moreover, Lachnospiraceae_XPB1014_group was negatively correlated with cellulase (r = −0.699, p < 0.05) and α-amylase (r = −0.514, p < 0.05). These findings suggest that the increasing concentrate supplementation alleviates body weight loss in lactating Tibetan sheep by orchestrating improvements in rumen histomorphology, digestive function, altering bacteria composition, and ruminal immune and modulating host epithelial gene expression. Full article

Tubular aggregates (TAs), ordered arrays of sarcoplasmic reticulum (SR) tubes, are the main morphological alteration found in muscle biopsies from patients affected by TA myopathy (TAM). TAM has been linked to mutations in the genes encoding for STIM1 and ORAI1, which are two proteins that mediate Store-Operated Ca²⁺ entry (SOCE). SOCE is a mechanism that allows recovery of extracellular Ca²⁺ during fatigue, when the SR becomes depleted. As TAs also form in fast-twitch muscle fibers of aging male mice (not in females), we studied the effect of sex hormones on the aggregation of TAs during aging. We administered estrogen (ad libitum in drinking water) to male mice from 10 to 18 months of age and then evaluated the following: (a) the presence of TAs using histology and electron microscopy (EM); (b) oxidative stress, a mechanism that could underlie damage to proteins and membranes (and possibly their accumulation in TAs); and (c) SOCE function during ex vivo stimulation in the presence or absence of external Ca²⁺ or SOCE blocker (BTP-2). The results collected indicate that treatment with estrogen (a) significantly reduced the formation of TAs; (b) reduced oxidative stress, which was elevated in aging male mice; and (c) restored SOCE, i.e., the capability of aged EDL muscles to use external Ca²⁺ by promoting maintenance of Ca²⁺ Entry Units (CEUs, the intracellular junctions that mediate SOCE). Finally, we also show that formation of TAs is reduced by treatment of mice with N-acetilcysteine (NAC), a potent antioxidant also administered ad libitum in drinking water. Full article

Background/Objectives: Chronic low back pain (CLBP) is a leading cause of disability worldwide, with lumbar medial branch radiofrequency ablation (LRFA) widely used to manage facet-mediated pain; however, emerging evidence raises concerns regarding its potential to denervate the multifidus muscle—an essential stabilizer of the lumbar spine—thereby exacerbating dysfunction. This narrative review synthesizes current evidence on multifidus atrophy and dysfunction following LRFA, emphasizes its clinical significance, and highlights gaps that warrant further research and therapeutic development. Methods: A comprehensive literature search was conducted using SANRA criteria across the Cochrane Library, Web of Science Core Collection, Scopus, PubMed, and MEDLINE. Studies assessing multifidus morphology or function after LRFA were identified and analyzed. Data were extracted from studies meeting predefined inclusion criteria. The narrative synthesis included a thematic analysis and interpretive integration focusing on clinical practice. Results: Six eligible studies were identified, five cohort studies and one case series. Of these, two confirmed decreased multifidus function post-LRFA. Four studies analyzed post-LRFA structural changes, two of which reported reduced cross-sectional area/fatty infiltration, one no measurable difference, and another an apparent enlargement. The findings are constrained by substantial differences in study design, patient populations, and outcome measures, which limit the ability to establish consistent conclusions. Conclusions: Current evidence suggests that LRFA may lead to structural and functional changes in the multifidus muscle, although findings remain inconsistent due to significant study heterogeneity. Further high-quality, prospective research with standardized imaging and functional assessments is needed to clarify the long-term clinical impact. Full article

Protein adsorption on orthopedic biomaterials during the initial intraoperative contact critically influences biological responses and osseointegration. Osteoconductive grafts such as β-tricalcium phosphate (β-TCP) and poly (ε-caprolactone)-β-TCP (PCL-TCP) can be functionally activated by exposure to autologous tissue. However, the composition and relevance of the resulting protein layer still remain unclear. In this study involving 10 patients undergoing primary total hip arthroplasty, β-TCP and PCL-TCP samples were incubated both in the femoral medullary cavity and within a surgical tissue collector harvesting autologous tissue (blood, bone fragments, muscle, and fat). Surface morphology was assessed microscopically, and protein adsorption was characterized via high-resolution LC-MS/MS with subsequent bioinformatics and statistical analysis. Both materials adsorbed over 2000 different autologous proteins. β-TCP showed higher overall protein concentrations, while PCL-TCP demonstrated greater proteomic diversity and incubation method-dependent shifts in protein profiles, influenced by surface roughness and wettability. Samples incubated in the tissue collector exhibited less protein variability and smaller material-specific differences compared to incubation in the femoral cavity, particularly for PCL-TCP. Predominant proteins were linked to immune regulation, stress response, and protein metabolism. These findings emphasize the impact of material properties and incubation environment on protein adsorption, with ex vivo incubation leading to more consistent protein adsorption patterns. Full article

Tubular aggregate myopathy (TAM) is an inherited skeletal muscle disease associated with progressive muscle weakness, cramps, and myalgia. Tubular aggregates (TAs) are regular arrays of highly ordered and densely packed straight-tubules observed in muscle biopsies; the extensive presence of TAs represent a key histopathological hallmark of this disease in TAM patients. TAM is caused by gain-of-function mutations in proteins that coordinate store-operated Ca²⁺ entry (SOCE): STIM1 Ca²⁺ sensor proteins in the sarcoplasmic reticulum (SR) and Ca²⁺-permeable ORAI1 channels in the surface membrane. Here, we assessed the therapeutic potential of endurance exercise in the form of voluntary wheel running (VWR) in mitigating TAs and muscle weakness in Orai1^G100S/+ (GS) mice harboring a gain-of-function mutation in the ORAI1 pore. Six months of VWR exercise significantly increased specific force production, upregulated biosynthetic and protein translation pathways, and normalized both mitochondrial protein expression and morphology in the soleus of GS mice. VWR also restored Ca²⁺ store content, reduced the incidence of TAs, and normalized pathways involving the formation of supramolecular complexes in fast twitch muscles of GS mice. In summary, sustained voluntary endurance exercise improved multiple skeletal muscle phenotypes observed in the GS mouse model of TAM. Full article

Ducks exhibit substantial ecological and dietary diversity, which drives morphological and functional adaptations in their digestive systems. This study analyzed the small intestine and cecum of three wild duck species: Mallard (Anas platyrhynchos), Tufted Duck (Aythya fuligula), and Green-Winged Teal (Anas crecca) collected post-mortem. Histomorphometric analysis and immunohistochemistry (IHC) with the pan-neuronal marker HuC/D were performed. The Tufted Duck showed the thickest intestinal muscle layers, particularly in the duodenum and ileum, and the largest enteric ganglia, indicating adaptation to a fibrous and protein-rich diet. The Mallard displayed the longest villi and deepest crypts, consistent with its omnivorous diet rich in plant material. The Green-Winged Teal, which consumes highly digestible insect-rich food, had the shortest villi and thinnest muscle layers. Differences in enteric ganglion size and organization among species suggest varying neuroregulatory demands in different gut segments. These findings confirm that intestinal morphology and enteric nervous system (ENS) structure are tightly linked to dietary specialization and ecological strategies. The results highlight the high adaptive plasticity of the avian digestive system in response to feeding behavior. Full article