Search Results (658)

The black-lip rock oyster, Saccostrea echinata, is an emerging aquaculture species; however, difficulties in regulating their gonad conditioning to full maturation and spawning have impacted industry progress. Addressing this challenge requires a deeper understanding of the molecular mechanisms underlying reproduction, particularly the signalling molecules (e.g., neuroendocrine hormones) that regulate gonad development and spawning, which remains poorly understood in this species. Therefore, we investigated the molecular neuroendocrine regulation of gonad maturation in S. echinata through the analysis of gonad histological changes correlated with gene expression in the visceral ganglia and gonad (of male and female) at pre- and post-spawn stages. Our targeted analysis of neuropeptide genes demonstrated that only LASGLVamide showed significant differential expression, being upregulated in the pre-spawn female gonad. Of the 26 reproductive-related genes identified, four were significantly upregulated in female gonad (SOX9, Dax1, Nanos-like, and Piwi-like), while an insulin-like peptide receptor was elevated in male visceral ganglia at post-spawn. Untargeted investigation revealed numerous transmembrane receptors significantly upregulated in the pre-spawn ovary, such as receptors for thyrotropin-releasing hormone, metabotropic glutamate, and 5-hydroxytryptamine, while mesotocin and oxytocin receptors were upregulated in pre-spawn male gonads. At the post-spawn stage, the visceral ganglia displayed upregulation of genes encoding stress-related proteins such as superoxidase dismutase and DnaJ homologue subfamily A member 1. These findings provide important insights into the complexities of neuroendocrine signalling molecules and establish a molecular foundation to guide selective breeding and broodstock management strategies that will support sustainable aquaculture development of black-lip rock oyster. Full article

To understand the changes in gonadal sex differentiation, digestive enzyme activity, and growth-related hormone levels in the larval and juvenile black scraper, Thamnaconus modestus, continuous sampling was conducted from 0 to 91 days post-hatching (dph). 17β-estradiol (E2) and testosterone (T) levels, six digestive enzymes, as well as T3, T4, GH, and IGF-I were detected. The results showed that oogonia or spermatogonia was observed at 60 dph. During the sex differentiation to female or male, both E2 and T levels significantly increased (p < 0.05), suggesting that E2 and T may induce the sex differentiation to female or male in T. modestus, respectively. The amylase activity from 0 to 35 dph showed a slow upward trend, which may be due to the transition from endogenous to exogenous nutrition at this time. From 12 to 25 dph, alkaline protease activity significantly decreased (p < 0.05), while acid protease levels significantly increased (p < 0.05), suggesting that as organs in the digestive system continue to develop, acid protease plays an important role. T3 and T4 could already be detected at 0 dph, and the T4 content was always much higher than T3 throughout the stages, indicating that T4 may play more important roles than T3. Additionally, the changes in IGF-I and GH content followed a trend of an initial increase, a subsequent decrease, and then an increase, ultimately showing an overall upward trend. These results indicate that T4, IGF-I, and GH play crucial roles in growth and development in the juvenile fish. In conclusion, the results of this study provide useful information for growth, artificial reproduction, and sex regulation in T. modestus. Full article

In the chicken industry, sex determination significantly affects production efficiency and raises ethical concerns in poultry farming. As a key economic species, maximizing the advantages of each sex is vital in modern intensive breeding. Therefore, understanding the mechanisms of sex determination and regulation is critical to advancing the poultry industry. Transcriptome analysis of 3.5-day-old White Leghorn chicken embryonic genital ridges (n = 30, 15 males and 15 females) was performed using sex-pooled samples (five embryos/replicate, three replicates/sex). Sequencing generated 39.6 GB of high-quality reads for inter-sex comparative analysis, revealing 283 significantly differentially expressed genes (DEGs). The DEGs were primarily enriched in pathways such as ribosome biogenesis, glycan biosynthesis and metabolism, and TGF-β signaling, which are potential candidate pathways for the differentiation of chicken embryonic gonads. Key DEGs (including SMAD2Z, FREM1, NR2F1, SEMA6A, NFIB, RNF165, SMAD7B, SMAD2W, SPIN1W, and HINTW) were validated by RT-qPCR, confirming the transcriptome sequencing results. Among the DEGs, we predict binding sites for NR2F1 and NFIB within the DMRT1 gene promoter and suggest that these factors may serve as potential upstream activators for the expression of DMRT1, and they may initiate high DMRT1 expression in the subsequent stages of male embryos and regulate testicular development. In conclusion, this study investigated DEGs in the gonads of male and female chicken embryos after 3.5 days of incubation and found that NR2F1 and NFIB may serve as potential upstream activators for the expression of DMRT1, which is involved in the early determination of chicken sex. Full article

Endocrine axes are pathways of interactions involved in various aspects of the organism’s functioning, also implicated in deviations from physiological states leading to pathological conditions. The hypothalamic–pituitary–adrenal (HPA) axis releases corticosteroid hormones promoting adaptation to environmental stimuli (acute stress) or inducing altered conditions due to long-term noxious solicitations (chronic stress). The HP–gonadal (HPG) axis regulates reproductive activities by releasing gonadal steroids. These axes have been shown to engage in reciprocal inhibition under certain conditions, particularly when they rise beyond normal ultradian and circadian fluctuations. Based on the literature data, we reconstructed a neuroendocrine network responsible for this type of interaction. Thereafter, we developed a model of the HPA-HPG inhibition based on a series of nonlinear interactions represented by a system of differential equations in the Matlab environment. The quantitative analysis of the system’s behavior revealed the occurrence of bifurcations leading to bistable behavior, allowing us to detect bifurcation parameters. Bifurcation arises as the system’s components increase hypersensitivity and sustained activity in response to activating inputs. This involves transition from a single low-activity attractor to two distinct attractors, with a new high-activity state representing a breakdown of homeostasis. These results provide insights into the potential involvement of the HPA-HPG interaction in neuroendocrine disorders, and the identification of therapeutic targets from bifurcation parameters. Full article

Kazakhstan holds the global leadership position in natural uranium mining. Nonetheless, the extraction and processing of radioactive ores has the potential to induce instances of radiological contamination. This study aimed to evaluate the radiological soil contamination at a former monazite, tin, and radioactive ore processing facility located in Ust-Kamenogorsk city. Pedestrian gamma–ray measurements revealed dose rates up to 1.00 µSv/h, significantly exceeding the natural background (0.16–0.18 µSv/h). The analysis of the 28 soil profiles demonstrated that deeper soil layers (below 60 cm) were significantly contaminated with radionuclides constituting production waste. Furthermore, the total activity in the superficial soil layer is in the range of 583–5275 Bq/kg (alpha emitters) and 641–1749 Bq/kg (beta radionuclides). The maximum of total radioactivity in the samples collected at the 80–100 cm layer was at the level of 22,482 Bq/kg (α-emitters) and 6845 Bq/kg for gross beta radiation. In consideration of the site’s proximity to public buildings, the calculated radiological hazard indices were calculated, revealing the potential danger for human health. The elevated excess lifetime cancer risk and annual gonadal dose equivalent obtained for the topsoil layer indicate a high level of radiological risk to the local population. The obtained results emphasise the necessity of developing rehabilitation strategies and long-term monitoring of the contaminated site, which is consistent with the global objectives of sustainable development in the field of environmental protection and public health. Full article

In Nile tilapia, one of the most important aquaculture species, males are larger than females, and an all-male monosex culture offers significant economic benefits. Although the pituitaries of genetic female (XX) and genetic male (XY) tilapia have identical expression levels of follicle-stimulating hormone (fsh), FSH receptor (fshr) expression remains relatively low in XY-undifferentiated gonads and then increases following morphological sex differentiation. The expression patterns of genes related to androgen biosynthesis in XY-undifferentiated gonads are similar to those of fshr during testis differentiation. This might imply that FSH has a potential function in testis differentiation through regulating the expression of genes related to androgen biosynthesis. To determine whether FSH signaling regulated androgen biosynthesis, we microinjected recombinant FSH (rFsh) into XY larvae during the early sex-differentiation stage. We compared the expression of various genes related to testis differentiation after injection. The genes hsd3b, cyp17a1, dmrt1, and gsdf were found to have higher expression in the rFsh treatment group. These results suggest that FSH signaling can activate androgen biosynthesis by regulating steroidogenic enzymes, including hsd3b and cyp17a1. Moreover, injected rFsh can upregulate dmrt1, which has a positive effect on the expression of gsdf. Therefore, during testis differentiation and development, FSH plays a role in both androgen synthesis and the expression of genes related to testis differentiation in Nile tilapia. Full article

Background/Objectives: Inactivation of the dnd gene involved in the development of primordial germ cells (PGCs) leads to the loss of gametes and halts reproductive development. Studies on sterile fish allow for the identification of genes and processes associated with GC differentiation. Methods: Atlantic salmon with GC-ablated testes were produced by temporal silencing of dnd. Gene expression was analyzed in sterile and fertile testes using 44k microarray and qPCR. Results: In sterile testes, transcripts of several GC markers were detected at low levels, suggesting the presence of cells with a GC-related expression profile that failed to initiate spermatogenesis. Expression of 260 genes was undetectable in the gonads of sterile males and females, and 61.5% of these were also inactivated during first maturation of fertile testes. This group was enriched with genes highly expressed in the brain, including those involved in endocrine and paracrine regulation, synaptic transmission, and numerous genes critical for brain development; among them, 45 genes encoding homeobox proteins. Another group of 229 genes showed increased expression in developing testes and included genes involved in neurosecretion and brain development regulation. GC-ablated testes showed increased expression of reproductive regulators such as amh and sdy and numerous immune genes, suggesting a reprogramming of GC-depleted testes. Temporal silencing of dnd indicated common developmental processes in the brains and gonads of Atlantic salmon testis that become inactive in testes at first maturation. These processes may play roles in PGC homing, the creation of a specific environment required for spermatogenesis, or facilitating communication between the gonads. Full article

Transition is an essential mechanism that drives the development of distinct cellular phenotypes and tumorigenesis. The expression of various types of testis cancer antigens (TCAs) in breast carcinomas suggests a potential transition to male germ cell features within the tumor. This study explores the cellular populations in breast cancer that express genes associated with male germ cell development. We re-analyzed published datasets to identify the germline-associated genes in breast tumors. We then experimentally validated the expression of the identified genes in 28 breast tissue tumor samples using a quantitative RT-PCR. Based on available datasets, we also performed single-cell RNA sequencing (scRNA-seq) to analyze the tumor heterogeneity and cellular clustering. A total of 455 overexpressed genes were identified that were related to fetal primordial germ cells (PGCs), particularly those in the male gonad. Our examinations showed a significant overexpression of five genes (CCNB1, CCNB2, PTTG1, RACGAP1, and UBE2C) in the tumor samples. The scRNA-seq analysis revealed 14 distinct cell clusters, characterized by different gene expression signatures and cell cycle phases. The breast tumor stromal cells were suggested as the main source of the germline-associated genes. This study provides insights into the molecular mechanisms and pathways involved in germ cell transition in breast carcinoma. Full article

FOXL2 (forkhead box protein L2) is a transcription factor, its function and regulatory mechanism have been mainly studied in mammals; related research on marine invertebrates is still insufficient. It was found that oogenesis was affected, and even a small number of cells resembling spermatogonial morphology appeared in C. farreri ovaries after the FOXL2 was knocked down through RNA interference (RNAi) technology in our laboratory previously. Based on previous research, this paper conducted transcriptome sequencing and differential expression analysis on the ovarian tissues between the experimental group (post-RNAi) and the control group (pre-RNAi) of C. farreri, and used recombinant C. farreri FOXL2 protein for antibody production in Chromatin Immunoprecipitation Sequencing (ChIP seq) experiments to comprehensively analyze the pathways and key genes regulated by FOXL2 during oogenesis. The results showed that in the RNAi experimental group, 389 genes were upregulated, and 1615 genes were downregulated. Among the differentially expressed genes (DEGs), the differential genes related to gender or gonadal development are relatively concentrated in physiological processes such as steroid hormone synthesis, spermatogenesis, gonadal development, and ovarian function maintenance, as well as the FoxO and estrogen signaling pathways. Combining transcriptome and ChIP-seq data, it was found that there were some genes related to sex gonadal development among genes which were directly regulated by FOXL2, such as Wnt4, SIRT1, HSD17B8, GABABR1, KRAS, NOTCH1, HSD11B1, cPLA2, ADCY9, IP3R1, PLCB4, and Wnt1. This study lays the foundation for a deeper understanding of the FOXL2′s specific regulatory mechanism during oogenesis in scallops as a transcription factor. Full article

Male infertility is a growing global concern with increasing prevalence in both developing and developed nations. While many associations between environmental factors and male infertility have been explored, the relationship between sleep deprivation and male infertility remains underexplored. This narrative review examines the reported effects of sleep deprivation on the Hypothalamic––Gonadal (HPG) axis, Hypothalamic–Pituitary–Adrenal (HPA) axis, oxidative stress, and testicular function, and their consequential effects on male infertility. Disruption of the HPG axis results in altered follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, leading to fluctuation in testosterone levels, negatively affecting spermatogenesis and other critical reproductive processes. Activation of the HPA axis, often due to stress, elevates cortisol levels, which, in turn, suppresses gonadotropin-releasing hormone (GnRH), impairing reproductive function. Reactive oxidative species (ROS) accumulate in periods of oxidative stress and have been shown to damage sperm and reduce their quality. The blood–testis barrier (BTB) is disrupted in states of sleep deprivation, leading to decreased sperm quality. A literature review was conducted using PubMed and Google Scholar to assess peer-reviewed studies from 1990 to 2024, revealing a complex interplay between sleep deprivation and male reproductive dysfunction. While existing studies support a link between sleep disturbances and hormonal dysregulation, further research is needed to establish causal relationships and identify potential therapeutic interventions. Addressing sleep deprivation may represent a modifiable factor in improving male fertility outcomes. Full article

Phthalates are widely used plasticizers recognized as endocrine-disrupting chemicals (EDCs) with well-documented adverse effects on reproductive health. These compounds act either directly or through their metabolites and can influence various biochemical pathways. Key phthalates that have been associated with potential toxic outcomes include di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), diisononyl phthalate (DiNP), and diisodecyl phthalate (DiDP). The presence of these compounds in everyday consumer products has been associated with various adverse effects on human reproductive health, including hormonal disruption, issues in gonadal function, and other hormone related problems. This systematic review provides an overview and critical synthesis of the most recent research regarding phthalate reproductive toxicity. The scope is to summarize and aggregate correlations between phthalate exposure and reproductive health outcomes and highlight factors, such as age, sex, and extent of exposure, that have the most significant impacts on clinical outcomes. The reported studies focus on the gender-specific outcomes of various phthalates, while the epidemiological data reveal the importance of exposure duration and age. The reported results highlight the need for strict regulations regarding phthalate usage and the importance of developing safer alternatives. Full article

Background: In high-altitude regions, sporadic two-year-old immature Chinese mitten crabs (Eriocheir sinensis) would overwinter and mature in their third year, developing into three-year-old crabs (THCs) with a cold-adaptive strategy. Compared to two-year-old crabs (TWCs) from low-altitude Jiangsu, THCs from Karst landform and high-altitude Guizhou exhibit significantly larger final size but lower gonadosomatic index (GSI) (p < 0.01). Methods: To elucidate the molecular mechanisms underlying this delayed ovarian development, integrated transcriptomic and proteomic analyses were conducted. Results: Results showed downregulation of PI3K-Akt and FoxO signaling pathways, as well as upregulation of protein digestion and absorption pathways. Differentially expressed proteins indicated alterations in mitochondrial energy transduction and nutrient assimilation. Integrated omics analysis revealed significant changes in nucleic acid metabolism, proteostasis, and stress response, indicating systemic reorganization in energy-nutrient coordination and developmental plasticity. Conclusions: The observed growth-reproductive inverse relationship reflects an adaptive life-history trade-off under chronic cold stress, whereby energy repartitioning prioritizes somatic growth over gonadal investment. Our transcriptomic and proteomic data further suggest a pivotal regulatory role for FOXO3 dephosphorylation in potentially coupling altered energy sensing to reproductive suppression. This inferred mechanism reveals a potential conserved pathway for environmental adaptation in crustaceans, warranting further functional validation. Full article

Pea crabs live in association with various marine invertebrates, particularly notable for their parasitic relationship with numerous bivalves of great economic importance. During a genetic study of mussel populations on the French Atlantic coast, these crabs were found in the mantle cavity of individuals in La Tranche-sur-Mer, predominantly affecting Mytilus edulis. Given the history of mass mortality events in this area, the apparent susceptibility of M. edulis to parasitism, and the negative impact of pea crabs on host physiology, this study focused on determining the crab species found and their effects on mussels. The prevalence of infestation in this population was high (64.6%), with 61.3% of infested mussels hosting one crab and 38.7% hosting two crabs. There were no significant differences in infestation rates between male and female bivalves. Genetic analysis (16S and H3) identified the crab as Pinnotheres pisum, of which two morphotypes were observed depending on sex and stage of development. Despite the high prevalence, infested mussels showed no evidence of impaired growth or reproductive development. However, long-term studies are recommended to explore whether subtle or cumulative physiological effects of crab infestations could indirectly contribute to the mass mortality events recorded in this area. Full article

Fish reproductive biology influences their life history and can impact their vulnerability to fisheries; therefore, for sustainable management and development, a proper understanding is crucial. Reproductive biology, including maturation, spawning season, fecundity, and sex ratio, was examined throughout the year in the Java Rabbitfish, Siganus javus, in the southern South China Sea. This study is the first to examine reproductive traits by collecting a total of 339 S. javus specimens monthly from September 2017 to August 2018 through detailed gonad histology. The spawning season of female S. javus was mainly restricted to July, August, October, and December, whereas male fish were found to spawn throughout the year. Inter-species variations in the spawning season were observed within the genus, which is influenced by interspecific spawning strategies and regional environmental factors. The sex ratio close to 1:1 suggests that the fish population is in equilibrium in the region. The fecundity of S. javus ranged from 1.8 × 10⁵ to 12 × 10⁵, which was similar to that of other species in Siganus, suggesting less inter- and intra-species variation in fecundity within the family. The middle maturation stage was absent throughout the year, probably due to the different habitat uses during their life history. Reproductive biology might influence other biological aspects, such as migration and behaviour in the fish. Full article

Lead (Pb) is a naturally occurring metal that is environmentally ubiquitous due to industrial activities, such as mining, smelting, and fossil fuel combustion. Exposure to Pb adversely affects the central nervous system, gastrointestinal tract, lungs, liver, bones, and cardiovascular system, leading to a multitude of negative health impacts, such as anemia and neurological disorders. While significant research has focused on the effects of Pb on the nervous and immune systems, Pb’s impact as a reproductive endocrine disruptor remains largely understudied. The first objective of this review was to collate the current literature regarding the effects of Pb on the reproductive system of aquatic species (primarily fish) and agricultural livestock to highlight the ecological significance and impacts on animal health. Literature supports the hypothesis that exposure to Pb can impede reproductive processes by affecting hormone levels, reproductive organ development, and fertility. A second objective of this review was to elucidate putative mechanisms underlying Pb as a reproductive endocrine disruptor using molecular data and computational approaches. Based on transcriptomics data, Pb is hypothesized to perturb key pathways important for hypothalamic–pituitary–gonadal axis functions, such as circadian regulation and estrogen receptor signaling. Given the widespread environmental presence of Pb, understanding these mechanisms is essential for improving risk assessments and protecting animal reproductive health. Full article