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Integrating transcriptomics and metabolomics reveals the molecular landscape of sperm maturation driven by regional differentiation in the epididymis of Guizhou-Guiqian semi-fine wool sheep.

Epididymal regionalized differentiation is crucial for sperm maturation. However, little is known about the synergistic remodeling mechanisms of different epididymal segments at the transcriptional and metabolic levels during sexual maturation in ruminants (especially sheep). We investigated the caput, corpus, and cauda epididymidis of pre-pubertal (2-month-old) and post-pubertal (7-month-old) Guizhou-Guiqian semi-fine wool sheep using histology, RNA sequencing, and metabolomics. Post-pubertal tissues exhibited increased luminal diameters, cilia lengths, and abundant cauda spermatozoa. Transcriptomic analysis revealed increasing differentially expressed genes (DEGs) along the caput-corpus-cauda axis (4642, 6103, and 7698 DEGs, respectively). Metabolomics detected 786 unique differentially accumulated metabolites (DAMs). Region-specific analysis showed that in the caput, up-regulated pathways (fructose/mannose metabolism; HK2, ALDOA, HKDC1) provide energy and substrates for initial sperm motility. In the corpus, down-regulated genes associated with extracellular matrix and tight junctions suggested epithelial barrier remodeling to establish an immune-tolerant microenvironment. The cauda specifically up-regulated the pentose phosphate pathway (FBP1, GPI) and glutathione metabolism, maintaining redox homeostasis for long-term sperm storage. Additionally, glycerophospholipid metabolism was enriched across all segments, where PEMT, AGPAT5, and LCAT likely regulate sperm plasma membrane fluidity. In conclusion, during sexual maturation, the caput drives energy metabolism and glycosylation, the corpus establishes immune tolerance, and the cauda maintains antioxidant homeostasis. The glycerophospholipid network throughout the across all epididymal segments synergistically remodels sperm membrane. This study reveals the underlying multi-omics regulatory mechanisms of epididymal functional differentiation, providing a theoretical basis for elucidating the molecular mechanisms of sperm maturation in this breed and for the molecular breeding of early reproductive performance in rams.

Animals

Influence of ovarian maturity, age, and mating status on the antennal responses of wild and laboratory reared Xyleborus affinis (Coleoptera: Curculionidae: Scolytinae) to ethanol.

Xyleborus affinis Eichthoff is a neotropical ambrosia beetle that, in certain regions such as the United States and Mexico, has been associated with exotic phytopathogenic fungi causing extensive tree mortality. Although studies relating its olfactory response to volatile compounds and trapping systems have been published, factors such as the insect's physiological condition, which can affect its recognition or response to odors, have not been studied. Here, we evaluated the electroantennographic (EAG) response of wild and laboratory reared X. affinis females to 70% ethanol, a compound known to attract these insects. The experimental design was developed to consider and compare the following conditions: (i) females collected inside and outside host-galleries, (ii) sexual maturity (with mature and immature ovaries), (iii) age (0, 1, 3, and 5 d after emergence), and (iv) mating status (virgins and mated). Our results indicate that most of the wild females located outside the galleries were sexually mature but exhibited significantly lower EAG response than those inside the galleries. Regarding mating status, mated females exhibited significantly stronger antennal responses compared to virgins, whereas age did not affect antennal sensitivity. Finally, we provide images of the hitherto undescribed reproductive system of X. affinis females, a key element that enabled this investigation. The information generated offers a useful foundation for future studies aimed at understanding the physiological mechanisms and other critical factors related to sensory perception and reproductive condition. For example, factors that may influence the behavior and attraction of X. affinis females to host semiochemicals.

Animals

Association between lean mass, fat mass, and waist circumference with bone mineral density in Mexican children and adolescents: a cross-sectional study.

To assess the associations of lean mass (LM), fat mass (FM), truncal fat mass (TFM), and waist circumference (WC) with bone mineral density (BMD) in Mexican youth, independently of body weight.&#xa0;We analyzed cross-sectional data from 1,054 children and adolescents from the Health Workers Cohort Study. We measured total and region-specific BMD, LM, and FM, with dual-energy X-ray absorptiometry. To eliminate the effect of body weight on FM, LM, TFM, and WC, weight-adjusted values were generated using the residuals method, and then we employed multivariate linear regression models adjusted for relevant potential confounders. We further stratified the analysis by sex, age group, and sexual maturation.&#xa0;LM was positively associated with BMD in various anatomical sites, with &#x3b2; coefficients ranging from 0.004 to 0.013 in both sexes (P&#x2009;<&#x2009;0.05). FM was inversely related to total BMD and other sites, with &#x3b2; coefficients ranging from -0.013 to -0.006 (P&#x2009;<&#x2009;0.05). WC showed negative associations with BMD at some sites, with &#x3b2; values ranging from -0.007 to -0.002. TFM was negatively associated with BMD. During puberty, the associations were consistent across all sites, whereas this was not the case for all sites after puberty. These patterns were similarly observed across different age groups.Conclusion:&#xa0;An increased LM and reduced FM are associated with higher BMD, particularly in the leg and hip regions, during childhood and adolescence, a critical developmental stage essential for healthy bone accrual and balance in adulthood.

Humans

Pupil dynamics in macaque recognition memory tasks: investigating physiological mechanisms.

Cognitive deficits are common in primates, particularly in memory and emotional processes. Rhesus monkey (Macaca mulatta), widely used in cognitive and behavioral research, are central to memory studies. The relationship between recognition memory performance and pupillary dynamics in rhesus monkeys remains underexplored. This study investigated pupil dynamics during recognition memory tasks and their physiological correlates in five sexually mature male rhesus monkeys. We measured pupil diameter and oscillatory features during tasks and analyzed the relationship between behavioral performance and physiological indicators. We found that the average correct response rate exceeded the random success level, and reaction times were significantly shorter during successful recognition than failures, highlighting their cognitive efficiency. During recognition of familiar scenes, average pupil diameter increased, while maximum change in pupil size decreased, indicating reduced cognitive load. Both the frequency and amplitude of pupillary oscillation were lower during successful trials, reflecting decreased cognitive conflict and effective processing. This change reflects a decrease in cognitive conflict and suggests that information processing was more effective. The absolute value of the pupil peak slope decreased during successful recognition, indicating more stable cognitive state. These results support that pupillary dynamics can serve as physiological markers of cognitive effort in rhesus monkeys. Future studies should investigate how stimulus characteristics influence recognition and incorporate measures, such as intracranial EEG and fMRI, to enhance our understanding of their neural mechanisms. This research supports the rhesus monkey model in cognitive neuroscience and contributes to understanding primate cognition and its physiological foundations, with implications for clinical and translational research.

Animals

Evaluation of germline transmission of electroporation-mediated double gene-edited cattle lines.

Gene editing in livestock using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) offers a promising approach for genetic improvement in cattle. This study evaluated germline transmission and mutation stability of double-knockout cattle generated by zygote electroporation. Previously reported myostatin/beta-lactoglobulin (MSTN/BLG) and newly generated &#x3b1;-1,3-galactosyltransferase (GGTA1/BLG) double-knockout cattle were produced using CRISPR/Cas9-mediated genome editing. Targeted deep sequencing demonstrated extensive somatic mosaicism across multiple tissues. Computer-assisted sperm analysis (CASA) demonstrated normal sperm motility in MSTN/BLG double-knockout males. Fertilization of wild-type oocytes produced heterozygous embryos, with mutation frequencies of 37.76&#x202f;&#xb1;&#x202f;10.74% at the MSTN locus and 54.80&#x202f;&#xb1;&#x202f;7.73% at the BLG locus, as assessed by T7 endonuclease I (T7E1) assay. MSTN/BLG double-knockout sperm were subsequently used for embryo production and for artificial insemination of GGTA1/BLG double-knockout females. Healthy offspring were successfully obtained (n&#x202f;=&#x202f;3), alongside one stillborn calf. Targeted deep sequencing of all four progenies revealed highly variable allele frequencies that deviated substantially from the approximately 50% expected for heterozygous germline transmission. In contrast, whole-genome sequencing (WGS) results were consistent with Mendelian expectations, underscoring the limitations of PCR-based targeted sequencing for assessing germline transmission in mosaic founders. These results show that CRISPR/Cas9-edited embryos generated by electroporation can develop into healthy, sexually mature cattle capable of germline transmission. While variable transmission rates were observed owing to founder mosaicism, non-mosaic F1 offspring were successfully generated. However, direct, embryo-mediated gene-editing strategies remain technically and economically challenging for large-scale commercial calf production, and reports in cattle are limited. This study provides a reference for future applications of gene-edited embryos and their germline propagation.

Animals

Ovarian expression and function of neuropeptide systems in teleosts and anurans.

The hypothalamic-pituitary-gonadal axis regulates reproduction, sexual maturation, and spawning behaviours. Its evolutionary origins trace back to primitive jawless fish and has been well characterized in teleosts. Recent advances in multi-species genome sequencing, annotation, and experimental approaches for identifying and characterizing key regulators have advanced understanding of neuroendocrine regulation in teleost reproduction, reshaping existing models. Early studies in amphibians established that steroids are critical regulators of final oocyte maturation. Subsequent work in anurans revealed complex interactions among theca cells, follicular cells, and oocytes, supporting a three-cell model in which oocytes contribute to their own steroidogenic environment, challenging the traditional two-cell view of ovarian steroidogenesis. In teleosts, however, direct evidence that oocytes support steroid precursor delivery to theca and follicular cells is limited, and whether a comparable three-cell model applies remains an open hypothesis. Across both taxa, the roles of locally produced neuropeptides in coordinating interactions among theca cells, follicular cells, and oocytes remain largely uncharacterized. Here, we provide a short review of the localization and potential autocrine/paracrine functions of neuropeptides in teleost and amphibian ovaries and discuss existing knowledge gaps. We identify opportunities to leverage detailed localization studies that map neuropeptides to specific ovarian cell types and developmental stages, and discuss how integrating traditional and emerging experimental approaches can advance comparative studies in ovarian endocrinology. This work will improve our understanding of reproductive regulation in fishes and frogs, with applications in captive breeding, aquaculture, and endocrine disruption research.

Autocrine

Steroid hormone-mediated epigenetic programming during puberty: uncovering links to depression.

DNA methylation (DNAm) is a key epigenetic modification that dynamically regulates eukaryotic development over time. DNAm has been found to influence a variety of biological processes in both normative and pathological states, such as depression. Since DNAm can serve as an interface between environmental influence and gene expression, it is a mechanism studied in the context of many pathologies, including psychiatric. Depression is a complex and heterogeneous disorder strongly influenced by puberty, as evidenced by increased rates in both sexes after sexual maturation. However, this effect is more pronounced in females, contributing to its twofold increased lifetime prevalence compared to males. Additionally, depression is consistently associated with altered DNAm at specific genomic sites. In this review, we discuss how DNAm programming can affect functional pathways during puberty and in turn, influence disease outcomes. Here, we highlight the bidirectional relationship of steroid hormone surges during this sensitive period and DNAm, adding a layer of complexity and insight into the pathophysiology of depression. Specifically, we explore the extent of DNAm change throughout puberty, how it contributes to individual and sex-specific differences in puberty, and how it may influence the risk for depression.

Humans

Age-related differences in semen quality in Holstein-Friesian bulls: a paired within-bull comparison of early and mature reproductive stages.

Genomic selection has changed dairy cattle breeding by increasing the use of young bulls for artificial insemination and shortening the reproductive lifespan of sires. Under these conditions, semen quality at the beginning of commercial use has become an important practical issue. Semen samples from 39 fertile Holstein-Friesian bulls used for commercial AI were collected between 2013 and 2016, during the introduction of genomic selection in Poland. This paired within-bull study compared semen collected from the same bulls at an early reproductive stage (13-20 months; young bulls, YB) and at full maturity (5-6 years; mature bulls, MB). The evaluation included conventional ejaculate traits, CASA-derived motility and kinematic descriptors, mtDNA copy number, and mitochondrial content per sperm cell. Importantly, all ejaculates met the quality requirements for commercial insemination. Ejaculate volume, sperm concentration, mitochondrial DNA copy number, and mitochondrial content did not differ significantly between age groups. The CASA-derived sperm movement profile, in contrast, differed with age. Semen from young bulls showed a higher proportion of progressively motile spermatozoa, whereas semen from mature bulls showed higher velocity-related parameters, including VSL, VCL, and STR. These findings indicate that bull age mainly affected sperm movement characteristics rather than semen output or mitochondrial content. Overall, the results support the use of young bulls in artificial insemination programs and show that age-related differences in semen quality are expressed mainly through changes in the post-thaw sperm motility and kinematic profile.

Animals

Degradation of ribosomal RNA during Plasmodium falciparum gametocytogenesis.

The life cycle of Plasmodium falciparum is characterized by complex regulatory changes that allow adaptation of the parasites to different environmental conditions, which are especially pronounced during transmission between the mammalian host and the insect vector. Previous studies have shown that P. falciparum uses three types of ribosomal RNAs (rRNA A, S1, and S2 types) at different stages of its life cycle. We used Oxford Nanopore Technologies direct RNA sequencing to investigate the dynamics of rRNA usage throughout the parasite's intraerythrocytic development, as well as in salivary gland sporozoites. Our study revealed a preponderance of A-type rRNAs during the intraerythrocytic cycle and gametocytogenesis, while S-type rRNAs slowly increase in abundance in mosquito stages starting 3 days post-infection. Salivary gland sporozoites showed an even proportion of all rRNA types. By examining the length distributions of rRNA molecules, we detected an extensive and specific degradation of rRNAs during gametocytogenesis, starting in stage II gametocytes and continuing until the final stages of gametocyte development. We hypothesize that rRNA degradation may be linked to the global translational repression and metabolic quiescence described in stage V gametocytes, similar to mechanisms observed in bacterial and eukaryotic stress responses.IMPORTANCEOur study uses Oxford Nanopore direct RNA sequencing of tightly synchronized blood-stage Plasmodium falciparum parasites to investigate the expression of ribosomal RNAs during asexual and sexual development. P. falciparum utilizes distinct types of rRNA during its development. However, due to the challenges of differentiating these highly similar molecules, their regulation and the mechanism underlying the switch between rRNA types remain unclear. We observe significant rRNA degradation in mature gametocytes, leading us to propose that this potentially leads to a reduced number of functional ribosomes when parasites become quiescent and translation is repressed.

Plasmodium falciparum

Silent cells? Potential for context-dependent gene expression in mature sperm.

Sperm are traditionally viewed as transcriptionally and translationally silent cells. However, observations that components of the cellular machinery of gene expression are maintained in ejaculated sperm are increasingly cited as challenges to this fundamental assumption. Here, we critically evaluate these arguments and present three lines of evidence from both model and non-model systems that collectively raise the question of whether ejaculated sperm may be capable of active gene expression. First, and critical for arguments surrounding the possibility of differential gene expression, we review recent evidence that spermatozoa may retain the capacity to transcribe and translate their genomes. Second, we highlight how sperm cells can exhibit differential transcript quantities across different post-ejaculation environments. Third, we ask whether the accumulating evidence of remarkable phenotypic plasticity in post-ejaculatory sperm phenotypes could be mechanistically underpinned by changes in sperm gene expression. While these lines of evidence are indirect and do not definitively show transcription of sperm genomes, we highlight how emerging technologies may enable us to test this hypothesis explicitly. Our review advocates for progress in this field and highlights several important evolutionary, ecological and practical implications that will probably transcend disciplines to the clinical and applied reproductive sectors.

Male