Search Results (28)

Introduction: The fartet (Apricaphanius iberus) and the samaruc (Valencia hispanica) are two endemic fish species from the Valencian Community that have experienced significant population declines due to habitat degradation, competition with invasive species, and the impacts of climate change. Despite their critical conservation status, key aspects of their population dynamics and reproductive biology remain poorly understood. Objective: This study aimed to assess the resilience of their embryos to water stress through diapause-like mechanisms. Methodology: For studying the embryonic arrestment, eggs were collected from captive populations and subjected to different incubation periods (1, 3, 7, 10 and 14 days) on different substrates (commercial sand and filter paper). Hatching rates were analyzed in relation to the duration of exposure to stress water conditions and the type of substrate used. Results: The experiments conducted demonstrated that the embryos of both species were able to withstand water stress conditions (eggs out of the water). In the case of the samaruc, the results showed that eggs collected in both May and June could resist water-stress conditions for at least 10 days, exhibiting hatching rates of 100% during this period, which decreased to 50% by day 14. Regarding the fartet, embryos from eggs collected in May were able to survive up to 3 days under water-stress conditions, with hatching rates of 100%. In contrast, embryos from eggs collected in June showed greater resilience to water stress, with high hatching rates of 60–100% at days 7 and 10. Conclusions: These results suggest that, although a mechanism like embryonic diapause may be present in these species, its effectiveness as an adaptive strategy may depend on multiple environmental factors not controlled in this study, such as temperature, oxygen availability, and water salinity. The absence of hatching after prolonged incubation periods indicates that, if a diapause mechanism exists in these species, it may not be as efficient as in other annual cyprinodontiforms adapted to extremely fluctuating environments. These results highlight the importance of adaptive management measures to mitigate the effects of climate change and ensure the long-term persistence of both species. Full article

Environmental pollution has emerged as one of the most significant threats to human and ecosystem health, with growing evidence suggesting that chronic exposure to toxic substances may accelerate aging. The concept of gerontogens, toxic compounds capable of accelerating this biological process, has gained increasing attention in toxicological research, particularly in the context of global demographic shifts toward older populations. Current research on gerontogens relies heavily on invertebrate models with short lifespans, such as Caenorhabditis elegans, Drosophila melanogaster, and Saccharomyces cerevisiae, which are valuable for studying conserved mechanisms in aging pathways, but present significant limitations for translational accuracy to many aspects of vertebrate biology. Vertebrate models traditionally employed in toxicology, including mice and zebrafish, require substantially longer experimental timelines and higher financial investments, making lifetime exposure and aging assays particularly challenging. In this context, the turquoise killifish Nothobranchius furzeri emerges as a highly promising vertebrate model for aging toxicology research. Recognized as the shortest-lived vertebrate species maintained under laboratory conditions, N. furzeri reaches sexual maturity within 14 days and displays complete senescence by 4 months of age, at which point individuals are considered elderly, offering a decisive advantage over conventional vertebrate models. Furthermore, its capacity for embryonic diapause enables practical embryo storage, long-distance transport, and synchronized hatching, greatly facilitating experimental designs. Although N. furzeri is well established in gerontological research, with studies addressing hallmarks of aging such as telomere shortening, neurodegeneration, and cellular senescence, its application in ecotoxicology remains remarkably limited, with fewer than 10 published studies to date. This article argues that N. furzeri may represent a critical bridge between toxicology and aging research, offering an efficient and translationally relevant platform for investigating the effects of environmental contaminants on vertebrate aging. Current limitations of the model, such as lack of husbandry standardization, are also discussed. Expanding its use in this field holds considerable potential for advancing evidence-based strategies in public health and environmental conservation related to chronic exposure to contaminants. Full article

m⁶A represents a prevalent epitranscriptomic modification in eukaryotes. The dynamic balance of m⁶A modification is governed by methyltransferases (writers), demethylases (erasers), and binding proteins (readers). m⁶A regulators are integral to critical biological processes, including embryonic development, cell differentiation, and stress responses. B. xylophilus, a highly destructive invasive plant-parasitic nematode, has caused considerable ecological and economic damage worldwide. However, the m⁶A regulatory system in PWNs has not yet been investigated. In this study, we systematically identified 21 m⁶A regulators in PWNs, including 10 writers, 6 erasers, and 5 readers, which belong to the METTL, ALKBH, and KH/RRM families. Phylogenetic and domain analyses revealed the evolutionary conservation and functional diversification of these protein families. Expression profiling indicated stage-specific expression patterns of m⁶A regulators during the egg, larval, diapause, and adult stages. Furthermore, significant responses were observed under low-temperature treatment, β-pinene exposure, and infection of Pinus thunbergii seedlings, with ALKBH family members exhibiting upregulation under all three stress conditions. Notably, unlike most eukaryotes, the PWN lacks canonical FTO/ALKBH5 demethylases and YTH-domain readers, instead relying on ALKBH6/8 and KH/RRM proteins. These findings suggest that this non-canonical m⁶A regulatory mechanism may contribute to the development and pathogenesis of B. xylophilus. Full article

Embryonic diapause, a state of developmental arrest in silkworm (Bombyx mori) eggs, poses a challenge for year-round sericulture. While physical stimuli like corona discharge can effectively terminate diapause, the underlying molecular mechanisms, particularly the initial events, remain poorly understood. This study employed an integrated transcriptomic and proteomic approach to analyze silkworm eggs within 48 h after corona treatment. Our time-series analysis revealed that the Hippo and Wnt signaling pathways were specifically activated as early as 1 h post-treatment, preceding the previously reported FoxO pathway response. We identified two temporally distinct gene clusters within the Hippo pathway, including immediate–early genes (e.g., Dachs_17/25/29, Ft_10) and late-phase effector genes, coordinating the exit from cell cycle arrest. Concurrently, the Wnt pathway was rapidly initiated, marked by the sustained upregulation of key regulators Notum and Pontin52, suggesting its role in unlocking the cell cycle. We propose a synergistic model wherein corona discharge triggers the concurrent, early activation of Hippo and Wnt signaling, which collectively reprogram the cell cycle and reinstate the developmental trajectory by promoting proliferation and suppressing apoptosis. These findings provide crucial insights into the initial molecular events of diapause termination, identifying Hippo and Wnt pathways as master regulators in transducing the physical corona stimulus into a developmental signal. Full article

In general, the silkworm, Bombyx mori, has a diapause trait in its eggs. Therefore, transgenic silkworm can be produced by embryonic microinjection using eggs laid by a non-diapause strain in B. mori. In this study, we performed microinjection using eggs of diapause strains which have good characteristics for industrial use, such as a big cocoon, thin and smooth silk, and tolerance against disease due to the growing industrial use of transgenic silkworms. For the conversion of egg diapause traits from diapause to non-diapause types, we used anti-serum against the diapause hormone of B. mori (BmDH), which was injected into maternal pupae, producing non-diapause eggs at a high rate. Finally, we attempted microinjection using three diapause strains with different voltinism (i.e., number of generations of an organism in a year) and were able to successfully produce transgenic silkworms in all three of them, demonstrating that our method is applicable to a wide range of silkworm strains with a diapause trait. Full article

Artemia is a typical animal used for the study of the diapause mechanism. The research on the regulation mechanism of diapause mainly focuses on the occurrence and maintenance of diapause. There are few studies on the mechanism of embryonic pause termination (EDT), especially for its transcriptional regulation mechanism. This study integrated transcriptional regulatory data from ATAC-seq and gene expression data from RNA-seq to explore the transcriptional regulatory mechanisms involved in the EDT process. Through integrated analysis, four important transcription factors (TFs), SVP, MYC, RXR, and SMAD6, were found to play a role in the EDT process, in which SVP, MYC, and RXR were upregulated, while SMAD6 was downregulated in the EDT stage. Through co-expression analysis, a transcription regulatory network for these four TFs was constructed and the functions of the TFs were analyzed. The expression of the TFs was further verified by RT-qPCR. Through functional analysis, SVP was found to be predominantly involved in cell adhesion and signal transduction. MYC probably played a role in protein binding. RXR may function in the process of RNA binding and the transfer of phosphorus-containing groups. Smad6 regulated the signal transduction, cell adhesion, and oxidation–reduction processes. The expression of the key TFs was verified by RT-qPCR. The results of this work provide important clues for the mechanism of transcriptional regulation in the EDT process of Artemia. Full article

In the present study, we investigated the possible correlation between insulin/ecdysone signaling and chilling-induced egg diapause termination in Bombyx mori. Changes in insulin (bombyxin-Z1) and ecdysteroid-phosphate phosphatase (EPPase) gene expression levels in chilled eggs (whose diapause had been terminated by chilling to 5 °C for 90 days) exhibited no significant increase after being transferred to 25 °C, which differed from both non-diapause eggs and HCl-treated eggs. We further compared the differential temporal expressions of insulin (bombyxin-A6, -Y1, and -Z1), ecdysone signaling (EPPase and E75A), and metabolic-related (trehalose transporter 1 (Tret1) and trehalase 1 (Treh1)) as well as sorbitol dehydrogenase 2 (SDH2) genes between chilled eggs and eggs kept at 25 °C. Our results showed that all gene expressions remained at very low levels in eggs kept at 25 °C. However, in chilled eggs, differential temporal changes were detected according to different genes, with bombyxin-A6 and EPPase gene expression levels being maintained at relatively constant, high levels. Higher expression levels of the E75A, Tret1, and Treh1 genes were also detected in chilled eggs. Expressions of the SDH2 and bombyxin-Z1 genes decreased during the first 15 days and then increased between days 30 and 90 of chilling. Ecdysteroid levels and phosphorylation of glycogen synthase kinase (GSK)-3β, a downstream target of insulin signaling, were maintained at relatively higher levels in chilled eggs. These results suggested that due to relatively higher insulin and ecdysone signaling levels in chilled eggs, relatively higher glucose metabolism was sustained, leading to the continued depletion of metabolic reserves. On day 30 of chilling, as a means to adjust nutrient requirements and maintain embryonic nutrient homeostasis, SDH2 gene expression began to increase, followed by increased expression of the bombyxin-Z1 gene. Along with high expressions of the bombyxin-Z1 and SDH2 genes, a decreased sorbitol level was suggested to eventually terminate diapause in B. mori eggs. To our knowledge, this is the first study to demonstrate the correlation between insulin/ecdysone signaling and chilling-induced embryonic diapause termination. Full article

We investigated the reproductive strategies and embryonic development of Acheilognathus rhombeus (a bitterling species that spawns in autumn) within its freshwater mussel host in the Bongseo Stream, South Korea. By focusing on survival mechanisms during critical stages of embryonic development, the selective use of mussel gill demibranchs by the bitterlings and associated adaptive traits were observed over 1 year. A significant diapause phase occurs at developmental stage D, which lasts for approximately 7 months, allowing embryos to survive winter. Development resumes when the temperature exceeds 10 °C. Minute tubercles on the embryos (crucial for anchoring within the host gill demibranchs and preventing premature ejection) exhibit the largest height during diapause, and the height decreases when developmental stage E is reached, when growth resumes. Acheilognathus rhombeus embryos were observed in 30.5% of the mussels, mostly within the inner gills, thereby maximizing spatial use and oxygen access to enhance survival. These results highlight the intricate relationship between A. rhombeus and its mussel hosts, demonstrating the evolutionary adaptations that enhance reproductive success and survival. This study provides valuable insights into the ecological dynamics and conservation requirements of such symbiotic relationships. Full article

Embryonic diapause is a common evolutionary adaptation observed across a wide range of organisms. Artemia is one of the classic animal models for diapause research. The current studies of Artemia diapause mainly focus on the induction and maintenance of the embryonic diapause, with little research on the molecular regulatory mechanism of Artemia embryonic reactivation. The first 5 h after embryonic diapause breaking has been proved to be most important for embryonic reactivation in Artemia. In this work, two high-throughput sequencing methods, ATAC-seq and RNA-seq, were integrated to study the signal regulation process in embryonic reactivation of Artemia at 5 h after diapause breaking. Through the GO and KEGG enrichment analysis of the high-throughput datasets, it was showed that after 5 h of diapause breaking, the metabolism and regulation of Artemia cyst were quite active. Several signal transduction pathways were identified in the embryonic reactivation process, such as G-protein-coupled receptor (GPCR) signaling pathway, cell surface receptor signaling pathway, hormone-mediated signaling pathway, Wnt, Notch, mTOR signaling pathways, etc. It indicates that embryonic reactivation is a complex process regulated by multiple signaling pathways. With the further protein structure analysis and RT-qPCR verification, 11 GPCR genes were identified, in which 5 genes function in the embryonic reactivation stage and the other 6 genes contribute to the diapause stage. The results of this work reveal the signal transduction pathways and GPCRs involved in the embryonic reactivation process of Artemia cysts. These findings offer significant clues for in-depth research on the signal regulatory mechanisms of the embryonic reactivation process and valuable insights into the mechanism of animal embryonic diapause. Full article

Genetic mutations leading to premature termination codons are known to have detrimental effects. Using the Lepidoptera model insect, the silkworm (Bombyx mori), we explored the genetic compensatory response triggered by mutations with premature termination codons. Additionally, we delved into the molecular mechanisms associated with the nonsense-mediated mRNA degradation pathway. CRISPR/Cas9 technology was utilized to generate a homozygous bivoltine silkworm line BmTrpA1^−/− with a premature termination. Transcript levels were assessed for the BmTrpA paralogs, BmPyrexia and BmPainless as well as for the essential factors Upf1, Upf2, and Upf3a involved in the nonsense-mediated mRNA degradation (NMD) pathway. Upf2 was specifically knocked down via RNA interference at the embryonic stage. The results comfirmed that the BmTrpA1 transcripts with a 2-base deletion generating a premature termination codon in the BmTrpA1^−/− line. From day 6 of embryonic development, the mRNA levels of BmPyrexia, BmPainless, Upf1, and Upf2 were significantly elevated in the gene-edited line. Embryonic knockdown of Upf2 resulted in the suppression of the genetic compensation response in the mutant. As a result, the offspring silkworm eggs were able to hatch normally after 10 days of incubation, displaying a non-diapause phenotype. It was observed that a genetic compensation response does exist in BmTrpA1^−/− B. mori. This study presents a novel discovery of the NMD-mediated genetic compensation response in B. mori. The findings offer new insights into understanding the genetic compensation response and exploring the gene functions in lepidopteran insects, such as silkworms. Full article

Artemia is a widely distributed small aquatic crustacean, renowned for its ability to enter a state of embryonic diapause. The embryonic diapause termination (EDT) is closely linked to environmental cues, but the precise underlying mechanisms remain elusive. In this study, ATAC-seq and RNA-seq sequencing techniques were employed to explore the gene expression profiles in Artemia cysts 30 min after EDT. These profiles were compared with those during diapause and 5 h after EDT. The regulatory mechanisms governing the EDT process were analyzed through Gene Ontology (GO) enrichment analysis of differentially expressed genes. Furthermore, the active G-protein-coupled receptors (GPCRs) were identified through structural analysis. The results unveiled that the signaling transduction during EDT primarily hinges on GPCRs and the cell surface receptor signaling pathway, but distinct genes are involved across different stages. Hormone-mediated signaling pathways and the tachykinin receptor signaling pathway exhibited heightened activity in the ‘0–30 min’ group, whereas the Wnt signaling pathway manifested its function solely in the ‘30 min–5 h’ group. These results imply a complete divergence in the mechanisms of signal regulation during these two stages. Moreover, through structural analysis, five GPCRs operating at different stages of EDT were identified. These findings provide valuable insights into the signal regulation mechanisms governing Artemia diapause. Full article

Cancer is one of the leading causes of death in the world. Various drugs have been developed to eliminate it but to no avail because a tumor can go into dormancy to avoid therapy. In the past few decades, tumor dormancy has become a popular topic in cancer therapy. Recently, there has been an important breakthrough in the study of tumor dormancy. That is, cancer cells can enter a reversible drug-tolerant persister (DTP) state to avoid therapy, but no exact mechanism has been found. The study of the link between the DTP state and diapause seems to provide an opportunity for a correct understanding of the mechanism of the DTP state. Completely treating cancer and avoiding dormancy by targeting the expression of key genes in diapause are possible. This review delves into the characteristics of the DTP state and its connection with embryonic diapause, and possible treatment strategies are summarized. The authors believe that this review will promote the development of cancer therapy. Full article

Diapause-like features can be extended to naïve mouse embryonic stem cells (mESCs) to induce paused pluripotency by using INK128 (mTi), a mammalian target of rapamycin (mTOR) inhibitor. As a core integrative pathway, mTOR senses diverse stimuli and translates these cues to coordinate several processes. We have previously shown that the withdrawal of leucine and arginine from the culture medium of naïve mESCs can induce features of a paused-pluripotent state, including reduced cell proliferation, cell cycle arrest, and reductions in glycolytic and oxidative metabolism. However, surprisingly, although mTi did indeed provoke a paused-like state, this was distinct from and less pronounced than what resulted from leucine and arginine removal, and, according to our results, these features did not seem to necessarily be mTOR-driven. Therefore, this possibility should be considered in further experiments, and mTOR inhibition when using INK128 should always be confirmed and not merely assumed when INK128 is present in the culture medium. Full article

Mink embryos enter a period of diapause after the embryo develops into the blastocyst, and its reactivation is mainly caused by an increase in polyamine. The specific process of embryo diapause regulation and reactivation remains largely unexamined. This study aimed to identify changes in metabolites in the early pregnancy of mink by comparing and analyzing in serum metabolites up to twenty-nine days after mating. Blood samples were taken on the first day of mating, once a week until the fifth week. Metabolomic profiles of the serum samples taken during this period were analyzed by ultra-performance liquid chromatography/mass spectrometry. Multivariate statistical analyses identified differential metabolite expression at different time points in both positive and negative ion modes. The levels of dopamine, tyramine, L-phenylalanine, L-tyrosine, tyrosine, L-kynurenine, L-lysine, L-arginine, D-ornithine, and leucine changed significantly. These metabolites may be associated with the process of embryo diapause and subsequent reactivation. Full article

Flesh-fly Sarcophaga similis larvae exhibit a photoperiodic response, in which short days induce pupal diapause for seasonal adaptation. Although the spectral sensitivity of photoperiodic photoreception is known, the photoreceptor organ remains unclear. We morphologically identified the Bolwig organ, a larval-photoreceptor identified in several other fly species, and examined the effects of its removal on the photoperiodic response in S. similis. Backfill-staining and embryonic-lethal-abnormal-vision (ELAV) immunohistochemical-staining identified ~34 and 38 cells, respectively, in a spherical body at the ocular depression of the cephalopharyngeal skeleton, suggesting that the spherical body is the Bolwig organ in S. similis. Forward-fill and immunohistochemistry revealed that Bolwig-organ neurons terminate in the vicinity of the dendritic fibres of pigment-dispersing factor-immunoreactive and potential circadian-clock neurons in the brain. After surgical removal of the Bolwig-organ regions, diapause incidence was not significantly different between short and long days, and was similar to that in the insects with an intact organ, under constant darkness. However, diapause incidence was not significantly different between the control and Bolwig-organ-removed insects for each photoperiod. These results suggest that the Bolwig organ contributes partially to photoperiodic photoreception, and that other photoreceptors may also be involved. Full article