Gene co-expression networks reveal sex-biased differences in musculoskeletal ageing.

Aging is a universal and progressive process involving the deterioration of physiological functions and the accumulation of cellular damage. Gene regulation programs influence how phenotypes respond to environmental and intrinsic changes during aging. Although several factors, including sex, are known to impact this process, the underlying mechanisms remain incompletely understood. Here, we investigate the functional organization patterns of skeletal muscle genes across different sexes and ages using gene co-expression networks (GCNs) to explore their influence on aging. We constructed GCNs for three different age groups for male and female samples, analyzed topological similarities and differences, inferred significant associated processes for each network, and constructed null models to provide statistically robust results. We found that each network is topologically and functionally distinct, with young women having the most associated processes, likely due to reproductive tasks. The functional organization and modularity of genes decline with age, starting from middle age, potentially leading to age-related deterioration. Women maintain better gene functional organization throughout life compared to men, especially in processes like macroautophagy and sarcomere organization. The study suggests that the loss of gene co-expression could be a universal aging marker. This research offers insights into how gene organization changes with age and sex, providing a complementary method to analyze aging.

Pre-Copulatory Sexual Selection Predicts Sexual Size Dimorphism: A Meta-Analysis of Comparative Studies.

Size differences between males and females are common across the tree of life (termed sexual size dimorphism; SSD), and have fundamental implications for ecology, life history and behaviour of both sexes. Conventionally, SSD is thought to evolve in response to sex-specific sexual selection but more recent work suggests that ecological processes can also promote sex-differences in size. Here, we provide a global test for the role of sexual selection in the evolution of sexual size dimorphism using data from 77 comparative studies spanning the major classes of the animal kingdom. We show that intense sexual selection typically correlates with male-biased SSD across species. Importantly, pre-copulatory but not post-copulatory sexual selection predicts SSD, suggesting a pervasive role of premating male-male competition and female choice to drive sex differences in body size. Collectively, our findings suggest that pre-copulatory sexual selection plays a major role in the evolution of male-biased SSD.

EARLY ELEVATIONS IN ARTERIAL PRESSURE: A CONTRIBUTOR TO RAPID DEPRESSIVE SYMPTOM EMERGENCE IN FEMALE ZUCKER RATS WITH METABOLIC DISEASE?

One of the growing challenges to public health and clinical outcomes is the emergence of cognitive impairments, particularly depressive symptom severity because of chronic elevations in metabolic disease and cerebrovascular disease risk. To more clearly delineate these relationships and to assess the potential for sexual dimorphism, we used lean (LZR) and obese Zucker rats (OZR) of increasing age to determine relationships between internal carotid artery (ICA) hemodynamics, cerebral vasculopathies and the emergence of depressive symptoms. Male OZR exhibited progressive elevations in perfusion pressure within the ICA, which was paralleled by endothelial dysfunction, increased cerebral arterial myogenic activation, and reduced cerebral cortex microvessel density. In contrast, female OZR exhibited a greater degree of ICA hypertension than male OZR, but maintained normal endothelial function, myogenic activation and microvessel density to an older age range than did males. While both male and female OZR exhibited significant and progressive elevations in depressive symptom severity, these were significantly worse in females. Finally, plasma cortisol concentration was elevated higher and at a younger age in female OZR as compared to males and this difference was maintained to final animal usage at ~17 weeks of age. These results suggest that an increased severity of blood pressure waves may penetrate the cerebral circulation more deeply in female OZR than in males, which may predispose the females to a more severe emergence of depressive symptoms with chronic metabolic disease while males may be more predisposed to more direct cerebral vasculopathies (e.g., stroke, transient ischemic attack).

Novel sex-specific genes and diverse interspecific expression in the antennal transcriptomes of ithomiine butterflies.

The olfactory sense is crucial for organisms, facilitating environmental recognition and inter-individual communication. Ithomiini butterflies exemplify this importance not only because they rely strongly on olfactory cues for both inter- and intra-sexual behaviours, but also because they show convergent evolution of specialized structures within the antennal lobe, called macro-glomerular complexes (MGCs). These structures, widely absent in butterflies, are present in moths where they enable heightened sensitivity to, and integration of information from various types of pheromones. In this study we investigate chemosensory evolution across six ithomiini species and identify possible links between expression profiles and neuroanatomical. To enable this, we sequenced four new high-quality genome assemblies and six sex-specific antennal transcriptomes for three of these species with different MGC morphologies. With extensive genomic analyses we found that the expression of antennal transcriptomes across species exhibit profound divergence, and identified highly expressed ORs, which we hypothesise may be associated to MGCs, as highly expressed ORs are absent in Methona, an Ithomiini lineage which also lacks MGCs. More broadly, we show how antennal sexual dimorphism is prevalent in both chemosensory genes and non-chemosensory genes, with possible relevance for behaviour. As an example, we show how lipid-related genes exhibit consistent sexual dimorphism, potentially linked to lipid transport or host selection. This study broadens the understanding of antennal chemosensory adaptations, suggesting a link between genetic diversity, ecological specialization, and sensory perception with the convergent evolution of MCGs. Insights into chemosensory gene evolution, expression patterns, and potential functional implications enhance our knowledge of sensory adaptations and sexual dimorphisms in butterflies, laying the foundation for future investigations into the genetic drivers of insect behaviour, adaptation, and speciation.

Nutritional quality regulates postnatal wing morph in pea aphids.

Aphids can produce winged or wingless offspring in response to environmental changes. Host nutrition is one of the extensively studied environmental factors influencing the plasticity of wing morphs of aphids. In this study, we found that the pea aphid, Acyrthosiphon pisum, produced a low proportion of winged offspring when fed on plants, but a significantly higher proportion on the artificial diet. Interestingly, when newly born nymphs were transferred back to the artificial diet after feeding on plants for six hours or longer, most nymphs became wingless. These results suggest that the wing morph state of pea aphids can change postnatally, potentially determined by the nutritional quality of their food. Furthermore, aphids feeding on the artificial diet exhibited higher levels of glucose and stronger insulin signaling activity compared with aphids on plants. Conversely, the amino acid levels were lower, and TOR signaling was weaker in aphids fed on the artificial diet. Insulin and the target of rapamycin (TOR) are the primary nutrient-sensing signaling pathways involved in controlling organism growth and have been implicated in regulating aphid wing morph plasticity. We tested whether these nutrient responsive pathways were involved in postanal wing determination of aphids. However, reducing amino acid content in the diet or inhibiting TOR with rapamycin resulted in a decrease of the winged morph, suggesting that the lower amino acid levels or TOR activity was not responsible for the higher proportion of winged morph on the artificial diet. These results suggest that nutritional quality, particularly sugars like sucrose and glucose, may regulate the postnatal wing morph of the pea aphid, likely via the insulin signaling pathway.

The roles of Growth Hormone dependent JAK-STAT5 and Lyn kinase signalling in determining lifespan and cancer incidence.

In rodents, loss of GH or its receptor is associated with extended lifespan. We aimed to determine the signalling process resulting in this longevity using GH receptor (GHR) mutant mice with key signalling pathways deleted and correlate this with cancer incidence and expression of genes associated with longevity. GHR uses both canonical JAK2-STAT signalling as well as signalling via LYN-ERK1/2 pathway. We utilised C57BL/6 mice with loss of key receptor tyrosines and truncation resulting in (1) loss of most STAT5 response to GH or (2) total inability to generate STAT5 to GH or (3) loss of Box1 to prevent activation of JAK2 but not LYN kinase or (4) total knockout of the receptor. For each mutant we analysed lifespan, histopathology to determine likely cause of death, and hepatic gene and protein expression. The extended lifespan is evident in the Box1 mutant males (retains Lyn activation) have median lifespan of 1016 days compared to 890 days for the Ghr-/- males. In the females, GhrBox1-/- mice have a median lifespan of 970 days compared to 911 days for the knockout females. Sexually dimorphic GHR-STAT5 is repressive for longevity, since its removal results in a median lifespan of 1003 days in females compared to 734 days for wild type females. Numerous transcripts related to insulin sensitivity, oxidative stress response and mitochondrial function are regulated by GHR-STAT5, however LYN responsive genes involve DNA repair, cell cycle control, and anti-inflammatory response. There appears to be a yin-yang relationship between JAK2 and LYN that determines lifespan.

The Sexual Dimorphism in Rectum and Protein Digestion Pathway Influence Sex Pheromone Synthesis in Male Bactrocera Dorsalis.

Sexual dimorphism is a crucial aspect of mating and reproduction in many animals, yet the molecular mechanisms remain unclear. In Bactrocera dorsalis, sex pheromones trimethylpyrazine (TMP) and tetramethylpyrazine (TTMP) are specifically synthesized by Bacillus strains in the male rectum. In the female rectum, Bacillus strains are found, but TMP and TTMP are not, indicating sexually dimorphic differences in sex pheromone synthesis. Our anatomical observations and precursor measurements revealed significant differences in rectal structure and ammonium levels between sexes.  In vitro and in vivo experiments reveal that ammonium is vital for sex pheromone synthesis in rectal Bacillus strains. Comparative transcriptome analysis identified ammonium-producing genes (carboxypeptidase B and peptide transporter) in the protein digestion pathway that show much higher expression in the male rectum than in the female rectum. Knocking down the expression of either carboxypeptidase B (or inhibiting enzyme activity) or peptide transporter decreases rectal ammonium levels significantly, resulting in the failure of sex pheromone synthesis in the male rectum. This study provides insights into the presence of sexual dimorphism in internal organs and their functionalities in male-specific sex pheromone synthesis and has significant implications for understanding the molecular mechanisms underlying sex pheromone synthesis by symbionts in insects.

Cephalometric Analysis of Maxillary Sinus for Gender Determination Using Lateral Cephalogram: A Novel Retrospective Study in the North Indian Population.

BACKGROUND: Underlying disorders of the maxillary sinus (MS), including a history of sinus surgeries, chronic sinusitis, or congenital anomalies can potentially impact sinus function and structure, necessitating careful evaluation and management. Moreover, intact sinuses are crucial in gender determination in forensic anthropology. The present study was undertaken to check the accuracy and reliability of MS in gender determination using morphometric parameters. MATERIALS AND METHODS: This retrospective study was carried out on 74 lateral cephalograms (37 males and 37 females) aged between 18 to 50 years from the North Indian population. The MS area was measured using a NewTom CBCT machine (NewTom, Imola, Italy) with slicer software. The anatomical landmarks for the sinus were identified, and the area was calculated in square millimeters (mm2). RESULTS: In terms of surface area, females had a mean of 13,210.40 mm2 with a standard error of 713.46. Males, however, exhibited a higher mean surface area of 18,713.82 mm2, but with a significantly larger standard error of 3,371.70. The difference in MS area between males and females was statistically significant (p<0.01). In the receiver operating characteristic (ROC) curve, the area under the curve (AUC) was 0.77, suggesting good discriminative ability. CONCLUSION: The MS area on lateral cephalograms shows significant sexual dimorphism. Overall, the findings suggest that the MS surface area can be a useful anatomical feature for distinguishing between male and female North Indian subjects, given the statistically significant difference and the good discriminative performance indicated by the ROC curve analysis.

Pollinator response to yellow UV-patterned versus white UV-patternless flower dimorphism in Anemone palmata.

Flower colour polymorphisms are uncommon but widespread among angiosperms and can be maintained by a variety of balancing selection mechanisms. Anemone palmata is mostly yellow-flowered, but white-flowered plants coexist in some populations. We analysed the distribution of colour morphs of A. palmata across its range. We also characterised their colours and compared their vegetative and sexual reproductive traits, pollinator attention and fitness. The range of A. palmata is limited to the Western Mediterranean, while white-flowered plants are restricted to Portugal and SW Spain, where they occur at low proportions. Yellow flowers have a characteristic UV pattern, with a UV-absorbing centre and UV-reflecting periphery, which is absent in the white morph. Colour features of both morphs were highly delineated, making it easy for pollinators to distinguish them. Both morphs were protogynous, with the same duration of sexual stages, and the main floral traits related to pollinator attraction, apart from flower colour, were similar. Hymenoptera and Diptera were the main pollinators, showing preference for the yellow morph, clear partitioning of pollinator groups between the two colour morphs and a marked constancy to flower colour during foraging. Both morphs combined clonal propagation with sexual reproduction, but sexual reproductive potential was lower in white-flowered plants. Finally, female fitness was higher in the yellow morph. Pollinator partitioning and colour constancy could maintain this polymorphism, despite the lower visitation rate and fitness of white-flowered plants, which could facilitate their clonal propagation.

A male-specific mechanism of meningeal nociceptor sensitization promoting migraine headache.

BACKGROUND: We wished to explore possible sexual dimorphism in mechanisms sensitizing or activating meningeal nociceptors that can promote the headache phase of migraine. METHODS: Male and female C57BL6J mice received either supradural orexin B and an inflammatory mediator cocktail (IM) with migraine-like pain behaviors and photophobia recorded. Expression of orexin 2 receptor (OX2R) in trigeminal ganglion (TG) and phosphorylated extracellular signal-regulated kinases (ERK) levels in trigeminal nucleus caudalis (TNC) were evaluated. Orexin B-induced excitability of TG cells was assessed with patch-clamp electrophysiology. Intranasal delivery of CRISPR/Cas9 plasmids was used to edit the expression of OX2R in the TG. RESULTS: Supradural orexin B induced migraine-like pain behaviors, photophobia and increased TNC ERK phosphorylation exclusively in males. Blockade of orexin signaling with supradural suvorexant, a dual orexin receptor antagonist, prevented, but did not reverse, migraine-like pain in males induced by supradural IM cocktail. OX2R expression was higher in male TG and orexin B increased TG neuron excitability in males. Intranasal OX2R CRISPR/Cas9 reduced TG receptor expression and orexin B-induced TNC ERK phosphorylation and prevented migraine-like pain induced by supradural orexin B in males. CONCLUSIONS: Our studies reveal a male-specific mechanism of TG nociceptor sensitization and migraine-like pain behavior mediated by orexin B/OX2R signaling. Sexually dimorphic mechanisms of trigeminal nociceptor sensitization and activation offer opportunities to improve patient outcomes by considering patient sex and may influence clinical trial design and interpretation.

Sex and disease regulate major histocompatibility complex class I expression in human lung epithelial cells.

Major histocompatibility complex class I (MHC I) molecules present peptides to CD8+ T-cells for immunosurveillance of infection and cancer. Recent studies indicate lineage-specific heterogeneity in MHC I expression. While respiratory diseases rank among the leading causes of mortality, studies in mice have shown that lung epithelial cells (LECs) express the lowest levels of MHC I in the lung. This study aims to answer three questions: (i) Do human LECs express low levels of MHC I? (ii) Is LEC MHC I expression modulated in chronic respiratory diseases? (iii) Which factors regulate MHC I levels in human LECs? We analyzed human LECs from parenchymal explants using single-cell RNA sequencing and immunostaining. We confirmed low constitutive MHC I expression in human LECs, with significant upregulation in chronic respiratory diseases. We observed a sexual dimorphism, with males having higher MHC I levels under steady-state conditions, likely due to differential redox balance. Our study unveils the complex interplay between MHC I expression, sex, and respiratory disease. Since MHC I upregulation contributes to the development of immunopathologies in other models, we propose that it may have a similar impact on chronic lung disease.

Sexual dimorphism in hepatic PPAR alpha and CYP4a12a expression is associated with reduced development of drug-induced non-alcoholic steatohepatitis in female IL-33-/- mice.

Males are at higher risk for developing metabolic dysfunction-associated steatohepatitis (MASH) than females; however, mechanisms mediating sexual dimorphism in MASH development are not completely understood. Nutrition-based mouse models suggest that dysregulated fatty acid biosynthesis promotes MASH. Drugs recapitulate MASH without diet variabilities. This brief report investigates associations of sexual dimorphism with male susceptibility to MASH utilizing a drug-induced MASH model and focuses on very-long-chain fatty acid biosynthesis pathways. We assessed male and female mouse livers at 5 and 15 weeks following MASH induction by immunizations and age-matched un-immunized controls utilizing Western blot. Our results suggest that PPAR alpha and CYP4a12a protect females, while CYP4v2 does not protect males from MASH development. Our results have important implications for understanding sexual dimorphism in the pathogenesis of MASH.

Histological observations and transcriptome analyses reveal the dynamic changes in the gonads of the blotched snakehead (Channa maculata) during sex differentiation and gametogenesis.

BACKGROUND: Blotched snakehead (Channa maculata) displays significant sexual dimorphism, with males exhibiting faster growth rates and larger body sizes compared to females. The cultivation of the all-male population of snakeheads holds substantial economic and ecological value. Nonetheless, the intricate processes governing the development of bipotential gonads into either testis or ovary in C. maculata remain inadequately elucidated. Therefore, it is necessary to determine the critical time window of sex differentiation in C. maculata, providing a theoretical basis for sex control in production practices. METHODS: The body length and weight of male and female C. maculata were measured at different developmental stages to reveal when sexual dimorphism in growth initially appears. Histological observations and spatiotemporal comparative transcriptome analyses were performed on ovaries and testes across various developmental stages to determine the crucial time windows for sex differentiation in each sex and the sex-related genes. Additionally, qPCR and MG2C were utilized to validate and locate sex-related genes, and levels of E2 and T were quantified to understand sex steroid synthesis. RESULTS: Sexual dimorphism in growth became evident starting from 90 dpf. Histological observations revealed that morphological sex differentiation in females and males occurred between 20 and 25 dpf or earlier and 30-35 dpf or earlier, respectively, corresponding to the appearance of the ovarian cavity or efferent duct anlage. Transcriptome analyses revealed divergent gene expression patterns in testes and ovaries after 30 dpf. The periods of 40-60 dpf and 60-90 dpf marked the initiation of molecular sex differentiation in females and males, respectively. Male-biased genes (Sox11a, Dmrt1, Amh, Amhr2, Gsdf, Ar, Cyp17a2) likely play crucial roles in male sex differentiation and spermatogenesis, while female-biased genes (Foxl2, Cyp19a1a, Bmp15, Figla, Er) could be pivotal in ovarian differentiation and development. Numerous biological pathways linked to sex differentiation and gametogenesis were also identified. Additionally, E2 and T exhibited sexual dimorphism during sex differentiation and gonadal development. Based on these results, it is hypothesized that in C. maculata, the potential male sex differentiation pathway, Sox11a-Dmrt1-Sox9b, activates downstream sex-related genes (Amh, Amhr2, Gsdf, Ar, Cyp17a2) for testicular development, while the antagonistic pathway, Foxl2/Cyp19a1a, activates downstream sex-related genes (Bmp15, Figla, Er) for ovarian development. CONCLUSIONS: This study provides a comprehensive overview of gonadal dynamic changes during sex differentiation and gametogenesis in C. maculata, establishing a scientific foundation for sex control in this species.

Blotched snakehead (Channa maculata) exhibits significant sexual dimorphism, as males display faster growth rates and larger body sizes compared to females. The cultivation of the all-male population of snakeheads holds substantial economic and ecological value. However, the mechanisms underlying sex determination and differentiation in C. maculata remain insufficiently elucidated. In this study, sexual dimorphism in growth became evident starting from 90 dpf through the measurement of body length and weight of male and female C. maculata at different developmental stages. Histological observations indicated that morphological sex differentiation in females and males occurred at 20­25 dpf or earlier and 30­35 dpf or earlier, respectively, corresponding to the appearance of the ovarian cavity or efferent duct anlage. Transcriptome analyses revealed divergent gene expression patterns in male and female gonads after 30 dpf, suggesting that the period preceding 30 dpf might be the critical time window for sex control in C. maculata. The periods of 40­60 dpf and 60­90 dpf marked the initiation of molecular sex differentiation in females and males, respectively. Male-biased genes (Sox11a, Dmrt1, Amh, Amhr2, Gsdf, Ar, Cyp17a2) likely play crucial roles in testicular differentiation and spermatogenesis, while female-biased genes (Foxl2, Cyp19a1a, Bmp15, Figla, Er) could be pivotal in ovarian differentiation and oogenesis. Additionally, numerous biological pathways linked to sex differentiation and gametogenesis were identified. Moreover, sexual dimorphism was observed in the levels of E₂ and T during gonadal differentiation and development. Based on these findings, it is hypothesized that in C. maculata, the potential male sex differentiation pathway, Sox11a­Dmrt1­Sox9b, activates downstream sex-related genes (Amh, Amhr2, Gsdf, Ar, Cyp17a2) for testicular development, while the antagonistic pathway, Foxl2/Cyp19a1a, activates downstream sex-related genes (Bmp15, Figla, Er) for ovarian development. This study provides a comprehensive overview of gonadal dynamic changes during sex differentiation and gametogenesis in C. maculata, thereby establishing a scientific foundation for sex control in this species.

Sex-dimorphic functions of orexin in neuropsychiatric disorders.

The orexin system regulates a variety of physiological functions, including the sleep-wake cycle, addiction, foraging behavior, stress and cognitive functioning. Orexin levels in central and peripheral are related to the pathogenesis of many diseases, most notably the narcolepsy, eating disorders, stress-related psychiatric disorders, and neurodegenerative diseases. Recently, it has been reported that the orexin system is distinctly sexually dimorphic, and is strongly associated with neuropsychiatric disorders. In this review, we analyzed advancements in the sex differences in the orexin system and their connection to psychoneurological conditions. Considering the scarcity of research in this domain, more research is imperative to reveal the underlying mechanisms.

The loss of riparian vegetation along streams causes morphological divergences in functional traits of semiaquatic insects (Heteropteran: Gerromorpha) in the eastern Amazon.

Understanding the effects of mining activities on Amazonian streams and their impact on aquatic communities is of paramount importance in the current context of resource overexploitation in society. In this study, we assessed the significance of the environment and interspecific interactions on the organization patterns of semiaquatic insect species in a mineral extraction region in the eastern Amazon. We utilized the morpho functional characteristics of 22 species from the suborder Gerromorpha (Heteropteran), considering both the abundance and sexual dimorphism of these species. Additionally, we quantified the density of riparian vegetation surrounding each stream to categorize sampling points and evaluate whether there are differences in species distribution patterns among categories. We sampled 16 sites, categorized into two treatments based on the percentage of riparian vegetation in forested and deforested areas located in the Capim River Basin. We did not find the action of environmental filters on the total assembly; however, we found significant morphological divergence for all the traits analyzed. On the other hand, the separation of streams into treatments with different portions of riparian vegetation showed that there are significant differences between them regarding species distribution patterns. Forested streams within a 500-m radius have species distributed over a larger area, indicating that these streams have greater resource availability or that species can use these resources more efficiently. Our results demonstrate the importance of riparian vegetation for the studied communities, as well as for mitigating the impacts caused by mining activities.

Latitudinal gradients and sex differences in morphology of the Black Oystercatcher (Haematopus bachmani).

Environment and behavior are widely understood to affect bird morphology, which can lead to differences among subspecies or populations within a wide-ranging species. Several patterns of latitudinal gradients in morphology have been described, though Allen's and Bergmann's rules are the most well-known and have been tested and confirmed across a diversity of taxa and species. These state that individuals at higher latitudes will have larger bodies (Bergmann's Rule) but smaller extremities (Allen's Rule) to conserve heat in colder climates. Migratory behavior also can influence avian morphology, particularly wing shape, where migratory birds tend to have longer, more pointed wings than residents. The Black Oystercatcher (Haematopus bachmani) is a large, partially migratory shorebird species restricted to intertidal habitats and distributed from Alaska to Baja California, spanning about 35° of latitude. A large proportion of Black Oystercatchers that breed in Alaska are migratory, where nearly all individuals breeding in British Columbia through the southern end of their range remain resident through the annual cycle. Their broad latitudinal range and diversity in migratory behavior may drive geographic variation in morphology. Here we evaluate three explanations for geographic variation in morphology of the Black Oystercatcher using data from seven sites across two regions: Alaska and British Columbia. We found evidence consistent with Allen's but not Bergmann's rule; birds in Alaska have shorter bills than those in British Columbia, and these findings held when controlling for body size using wing length. Despite regional differences in migratory behavior, we detected no difference in the wing shape of birds in Alaska and British Columbia. Differences between sexes and among sites suggest that multiple factors drive patterns of morphological variation in the Black Oystercatcher.

Sensory cues of predation risk generate sex-specific changes in neural activity and behavior, but not hormones, in Trinidadian guppies.

How an organism responds to risk depends on how that individual perceives such risk. Integrating cues from multiple sensory modalities allows individuals to extract information from their environment, and whether and how the brain and body respond differently to different sensory cues can help reveal mechanistic decision-making processes. Here, we assessed neural, hormonal, and behavioral responses to different sensory cues of predation risk in Trinidadian guppies (Poecilia reticulata). Adult guppies were assigned to one of four treatment groups: control, visual, olfactory, and both sensory cues combined from a natural predator, the pike cichlid (Crenicichla alta), for 2 h. We found no difference in glucocorticoid response to any cue. However, we found behavioral and neural activation responses to olfactory-only cues. In addition, we found a sex by treatment effect, where males showed greater changes in neural activation in brain regions associated with avoidance behavior, while females showed greater changes in neural activation in regions associated with social behavior and memory, mirroring sex by treatment differences in behavioral antipredator responses. Altogether, our results demonstrate that single and combinatory cues may influence risk-taking behavior differently based on sex, suggesting that perception and integration of cues can cascade into sex differences in behavior.

Assessment of age-dependent sexual dimorphism in paediatric vertebral size and density using a statistical shape and statistical appearance modelling approach.

This work focuses on the growth patterns of the human fourth lumbar vertebra (L4) in a paediatric population, with specific attention to sexual dimorphism. The study aims to understand morphological and density changes in the vertebrae through age-dependent statistical shape and statistical appearance models, which can describe full three-dimensional anatomy. Results show that the main growth patterns are associated with isotropic volumetric vertebral growth, a decrease in the relative size of the vertebral foramen, and an increase in the length of the transverse processes. Moreover, significant sexual dimorphism was demonstrated during puberty. We observe significant age and sex interaction in the anterior vertebral body height (P = 0.005), where females exhibited an earlier increase in rates of vertebral height evolution. Moreover, we also observe an increase in cross-sectional area (CSA) with age (P = 0.020), where the CSA is smaller in females than in males (significant sex effect P = 0.042). Finally, although no significant increase in trabecular bone density with age is observed (P = 0.363), a trend in the statistical appearance model suggests an increase in density with age.

Age, Sex, and Training Specific Effects on Cross-Education Training.

An extensive number of publications have examined cross-education effects with adults, primarily investigating contralateral homologous (same) muscles. There are far fewer investigations on cross-education effects on contralateral heterologous (different) muscles and age (youth vs adult) and no studies investigating sex differences. Hence, the objective was to compare cross-education in female and male youth and young adults to contralateral homologous (chest press [CP], elbow flexors and extensors, handgrip isometric strength, and shot put) and heterologous (leg press, knee extension isometric strength, and countermovement jump) muscles. Twenty-eight female adults, 28 female youth, 28 male adults, and 28 male youth (total: 112) were examined before and after an 8-week (3 sessions/wk) unilateral, dominant arm, CP training program. Unilateral testing assessed dominant and nondominant leg press and CP 1-repetition maximum, knee extensors, elbow extensors, elbow flexors, and handgrip maximum voluntary isometric contraction (MVIC) strength, as well as shot put distance and countermovement jump height. Unilateral CP training induced training specific (CP 1-repetition maximum) and nonspecific (elbow extensors, elbow flexors, handgrip MVIC force, and shot put distance) improvements (P < .04, η2: .45-.85) but no significant lower body improvements. There was evidence for testing limb specificity as the dominant arm provided significantly (P < .021, η2: .17-.75) greater training gains than the nondominant arm. Youth's training adaptations exceeded with unilateral CP 1-repetition maximum, elbow extensors MVIC force, and shot put distance (P < .049, η2: .14-.49). No sex main effect differences were apparent. In conclusion, cross-education was training specific (greatest gains with upper body and dominant limbs) with greater benefits for youth and generally no sex differences with the exception of elbow extensors MVIC.

Sex-specific effects of PNPLA3 I148M.

Metabolic dysfunction-associated steatotic liver disease (MASLD, previously termed NAFLD, nonalcoholic fatty liver disease) is a complex multifactorial disease showing generally higher prevalence and severity in men than in women. With respect to women, men are also more prone to develop metabolic dysfunction-associated steatohepatitis, fibrosis and liver-related complications. Several genetic, hormonal, environmental and lifestyle factors may contribute to sex differences in MASLD development, progression and outcomes. However, after menopause, the sex-specific prevalence of MASLD shows an opposite trend between men and women, pointing to the relevance of oestrogen signalling in the sexual dimorphism of MASLD. The patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene, that encodes a triacylglycerol lipase that plays a crucial role in lipid metabolism, has emerged as a key player in the pathogenesis of MASLD, with the I148M variant being strongly associated with increased liver fat content and disease severity. Recent advances indicate that carrying the PNPLA3 I148M variant can be a risk factor for MASLD especially for women. To elucidate the molecular mechanisms underlying the sex-specific role of PNPLA3 I148M in the development of MASLD, several in vitro, ex vivo and in vivo models have been developed.