Search Results (188)

Background/Objectives: It is challenging to develop efficient vaccines against intracellular pathogens such as viruses, and since viral infections are one of the main challenges for farmed salmon, a novel vaccine strategy is needed. mRNA vaccines are optimized and approved for humans, but for fish, the mRNA technology is new, and optimization is required to ensure efficient protein expression. We made an mRNA tailored to salmon and studied the effect of modified nucleosides and the length of the poly(A) tail on protein expression from in vitro-transcribed mRNA in CHSE-214 cells, using enhanced green fluorescent protein (EGFP) as a reporter. Methods: Different lengths of the poly(A) tail were tested, and various modified nucleotides were incorporated in the mRNA during in vitro transcription, including pseudouridine (Ψ), N1-methylpseudouridine (m1Ψ), N6-methyladenosine (m6A), 5-methyluridine (m5U), and 5-methylcytidine (m5C). Protein expression was observed in fluorescence microscopy and quantified using flow cytometry. Results: mRNA containing Ψ resulted in the strongest EGFP expression 1–3 days post-transfection (dpt), while EGFP expression from m5C mRNA was high throughout the experiment (<10 dpt). m5U-containing mRNA had low EGFP expression until 6 dpt, but reached the level of m5C mRNA at 10 dpt. The m5U mRNA, however, expressed EGFP at much higher intensity than all the other mRNAs at all time points. Poly(A) tails with lengths of 40, 100, and >100 were tested, and the one with >100 adenines showed the highest expression. The effects of phosphatase treatment and purification of the mRNA were also investigated. Furthermore, EGFP expression was observed in yolk-sac salmon larvae following micro-injection. Conclusions: Our study provides an important basis for the development of efficient mRNA-based vaccines in the future. Full article

Pulmonary bioengineering holds significant promise for the development of functional lungs suitable for transplantation in patients with terminal lung diseases; however, it encounters considerable challenges. The inherent structural complexity, diverse cellular composition, and the intricate process of re-endothelialization the pulmonary vasculature complicate efforts to reconstruct viable lungs for transplantation. This study aimed to establish an innovative re-endothelialization technique utilizing decellularized scaffolds, integrating canine yolk sac-derived endothelial precursor cells with mechanical respiratory stimuli within a bioreactor framework. Wistar rat lungs were subjected to a decellularization protocol employing SDS + Triton X-100 0.5% and subsequently assessed for cytocompatibility with murine fibroblasts (3T3) and yolk sac (YS) cells in fragments. Following this, the recellularization of the whole-lung scaffold was evaluated under constant mechanical respiratory stimulation with YS cells. Each stage of the process was rigorously analyzed using histological staining, DAPI, scanning electron microscopy (SEM), and genomic DNA quantification. The findings reveal that the implemented alternating decellularization protocol resulted in a structured scaffold conducive to the culture of various cell types in fragments. When subjected to the complete scaffold recellularization model, the results indicated that YS cells are advantageous for the re-endothelialization process. Moreover, when employed in conjunction with the bioreactor model incorporating respiratory stimulation, these cells demonstrated enhanced cellular diffusion capacity and facilitated more homogeneous recellularization of the entire organ. These results signify a notable advancement in the reconstruction of new tissues for pulmonary transplantation. Full article

The rising global demand for lithium has led to substantial accumulation of lithium slag, a by-product of lithium carbonate production and a potential environmental contaminant. Leachates from this material contain various metal elements and may pose risks to ecosystems and organismal health. However, research on its neurotoxicity and underlying mechanisms remains limited. In this study, zebrafish embryos at 6 h post-fertilisation were exposed to varying concentrations of lithium slag leachate for 7 days. The leachate contained multiple metal ions (Li, Fe, Mn, Ni, Zn, As, Cr, Cu, Hg, Cd, Pb, etc.). Following exposure, significant metal accumulation was observed in larvae, accompanied by developmental malformations (yolk sac oedema, cardiac haemorrhage, and uninflated swim bladders). Behavioural assessment revealed reduced swimming distance and velocity, along with disrupted circadian rhythms. Biochemical analyses showed elevated Reactive oxygen species (ROS), Superoxide dismutase (SOD), Catalase (CAT), and Malondialdehyde (MDA), alongside decreased Glutathione (GSH), indicating oxidative stress. Transcriptomic analysis confirmed downregulation of core circadian genes. Neurotransmitter assays revealed decreased acetylcholine (Ach), noradrenaline (NE), and dopamine (DA), with increased gamma-aminobutyric acid (GABA) and serotonin (5-HT). These findings demonstrate that lithium slag leachate induces oxidative stress, circadian disruption, and neurobehavioural toxicity in zebrafish, providing important evidence for environmental risk assessment. Full article

Sanitization of hatching eggs is part of established poultry management practices, and its effectiveness is essential for productive success. This study aimed to investigate the relationships between microbiological and incubation performance variables obtained from a controlled experimental dataset of hatching eggs subjected to sanitization with essential oils or not under commercial conditions, and to determine the efficacy of these sanitizers, using a multivariate approach. Data were analyzed using principal component, canonical, cluster, and discriminant analysis. The results suggested that bacterial contamination of the eggshell may promote internal contamination, leading to embryonic mortality. Essential oil-based treatments are associated with lower microbial indicators and improved hatchability, while formaldehyde showed an opposite trend despite its antibacterial efficacy. Multivariate analyses clarified the interrelationships between microbiological and incubation performance variables, allowing the identification of response patterns that evidenced the functional efficiency of essential oil–based treatments for hatching egg sanitization under commercial conditions. Full article

Pure mediastinal yolk sac tumor is an uncommon and aggressive malignant germ cell neoplasm that presents considerable diagnostic difficulties owing to its pronounced clinical and morphological variability. Mediastinal yolk sac tumors, in contrast to their gonadal equivalents, typically occur at later stages, are typically associated with mixed germ cell components, and have a diverse array of histologic patterns that may resemble both germ cell and somatic malignancies. Accurate identification of these types of cancer is essential since diagnostic misclassification may significantly impact treatment and prognosis. This review provides a comprehensive overview of the morphologic spectrum of mediastinal yolk sac tumor, with emphasis on both classic and variant histologic patterns, including reticular, solid, glandular, papillary, hepatoid, and other less common growth forms. The immunohistochemical correlations of these patterns and their role in resolving diagnostic dilemmas are discussed, along with key differential diagnoses encountered in small mediastinal biopsy specimens. Particular attention is given to the limitations of limited tissue sampling, the impact of post-chemotherapy morphologic changes, and the potential for misinterpretation in this challenging anatomic site. By integrating morphologic features with clinical, radiologic, and laboratory findings, this review aims to enhance diagnostic accuracy and improve recognition of mediastinal yolk sac tumor across its diverse presentations. Full article

Chlorinated polyfluoroalkyl ether sulfonate (F-53B), a common substitute for perfluorooctane sulfonate (PFOS), exhibits similar environmental persistence and bioaccumulation potential, raising concerns about its ecological and health impacts. However, comprehensive toxicological data remain limited for adequate environmental risk assessment. In this study, we evaluated the developmental toxicity of F-53B using embryos/larvae of a commercially important benthic fish, blotched snakehead (Channa maculata). Embryos (<1 h post-fertilization, hpf) were exposed to various concentrations of F-53B (0.002, 0.02, 0.2, and 2 mg/L) for 120 h. Exposure resulted in concentration-dependent adverse effects, including reduced hatching success, increased mortality, and morphological malformations (yolk sac edema, spinal curvature). Histopathological analysis revealed substantial hepatic injury (vacuolization, nuclear pyknosis) and intestinal damage (villi atrophy) at higher concentrations (0.2 and 2 mg/L). Mechanistically, F-53B induced oxidative stress through inhibition of superoxide dismutase (SOD) and catalase (CAT), depletion of glutathione (GSH), and elevated malondialdehyde (MDA). Additionally, the observed immune dysregulation was characterized by the up-regulation of pro-inflammatory cytokines, including interleukin 1β (IL-1β), interleukin 8 (IL-8), and tumor necrosis factor-α (TNF-α), consistent with activation of the TLR-MAPK signaling pathway, and coincided with a shift from metabolic adaptation to pronounced inflammation. These integrated findings indicate that F-53B impairs early development in C. maculata through pathways involving oxidative damage, tissue injury, and immune disruption. This underscores the ecological risk F-53B poses to aquatic organisms and highlights the need for more comprehensive environmental risk assessment. Full article

Understanding embryonic development is fundamental to improving captive breeding protocols and supporting conservation strategies for threatened fish species. Prochilodus vimboides is a Neotropical freshwater fish for which detailed information on early ontogeny remains scarce. This study aimed to characterize the embryonic and early larval development of P. vimboides under captive conditions. Broodstock were hormonally induced to reproduce, and extrusion occurred between 209 and 230 degree-hours after induction at 21.49 ± 0.15 °C. Embryonic development was monitored at regular intervals after fertilization (AF) using freshly collected eggs examined under a stereomicroscope. The principal developmental stages were identified, namely zygote, cleavage, including morula and blastula, gastrula, organogenesis, and hatching. Fertilized oocytes exhibited marked hydration and formation of a large perivitelline space at 15 min AF. More than 50% of embryos reached the two-blastomere stage by 20 min AF, and cleavage continued until 2 h 14 min AF. The gastrula stage was observed at 3 h 23 min AF, blastopore closure occurred at 11 h 47 min AF, and organogenesis began at 12 h 55 min AF. Complete hatching occurred at 22 h 04 min AF, and larvae subsequently initiated yolk sac absorption without cannibalistic behavior. These findings provide a species-specific developmental framework that supports captive production and conservation efforts for P. vimboides in the Paraíba do Sul River Basin. Full article

Paediatric ovarian neoplasms are rare and histologically diverse tumours with distinct clinical behaviour and prognosis compared to their adult counterparts. This review synthesises current knowledge from an anatomical pathology perspective, emphasising diagnostic and therapeutic strategies. Paediatric ovarian tumours are classified into three main categories: germ cell tumours, sex cord-stromal tumours, and epithelial neoplasms. Germ cell tumours, the most frequent in children, include dysgerminoma, mature and immature teratoma, yolk sac tumour, and choriocarcinoma. Sex cord-stromal tumours encompass Sertoli-Leydig cell tumours, juvenile granulosa cell tumours, and adrenal-like stromal tumours, while epithelial tumours, rare in paediatric patients, include serous and mucinous adenocarcinomas or cystadenomas. Clinical presentation is often nonspecific, with abdominal pain, pelvic mass, or endocrine abnormalities. Diagnosis integrates imaging, serum tumour markers, and histopathology supported by immunohistochemistry. Treatment prioritises fertility-sparing surgery, with selective adjuvant chemotherapy based on histotype and stage. Despite generally favourable outcomes, the rarity of these tumours limits high-quality evidence, highlighting the need for referral centres and multicenter studies. Standardised diagnostic protocols and personalised therapeutic approaches are essential to optimising clinical outcomes and preserve long-term reproductive function. Full article

2-acetylfuran is a product of the Maillard reaction and is widely found, especially in heat-processed foods such as grain products, baked goods, and dairy products. Although 2-acetylfuran contributes to flavor, high concentrations may be toxic. Its target organs and dose–response relationships remain poorly characterized. In this study, transgenic zebrafish with fluorescently labeled immune and neural systems were used to assess the effects of 2-acetylfuran on immune and neural development. Wild-type zebrafish were employed to assess the toxicity of 2-acetylfuran on locomotor ability, gastrointestinal development, and liver function. The maximum non-lethal concentration (MNLC) and the 10% lethal concentration (LC₁₀) for zebrafish embryos were 0.844 and 0.889 μL/mL, respectively. Regarding immunotoxicity, at concentrations of 0.281, 0.844, and 0.889 μL/mL, 2-acetylfuran significantly reduced the numbers of neutrophils, T cells, and macrophages. Regarding locomotor and neurotoxicity, motor speed and total locomotor distance were significantly reduced at 0.844 and 0.889 μL/mL. These findings were consistent with neurodevelopmental assessments, in which 0.844 μL/mL 2-acetylfuran resulted in a significant increase in apoptotic cells in the central nervous system and markedly shortened peripheral motor nerve lengths. Regarding gastrointestinal toxicity, 0.844 and 0.889 μL/mL 2-acetylfuran significantly reduced the gastrointestinal area, while neutrophil counts showed no significant changes, suggesting a relatively mild effect on the gastrointestinal tract. Regarding hepatic toxicity, all tested concentrations of 2-acetylfuran primarily increased the delayed yolk sac absorption area. Furthermore, at 0.844 μL/mL, histological examination revealed hepatic pathological changes characterized by hepatocyte nuclear swelling, vacuolar degeneration, and hepatocyte necrosis. In summary, this study reveals the multi-organ toxicity profile of 2-acetylfuran in the zebrafish model, with particularly high sensitivity in the immune system and liver. This research provides theoretical support for risk assessment and process control of 2-acetylfuran in foods. Full article

Mammalian placentation represents one of the most striking evolutionary innovations among vertebrates, and accumulating evidence indicates that virus-derived genes—particularly the metavirus-derived PEG10 and PEG11/RTL1—have played indispensable but distinct roles: PEG10 in the emergence of therian viviparity and PEG11/RTL1 in the subsequent differentiation between marsupial and eutherian placental types. Notably, the metavirus-derived SIRH/RTL gene group, which includes PEG10 and PEG11/RTL1, exhibits unique and diverse functions not only in placenta development but also within microglia of the brain. Because microglia originate from yolk sac progenitors, these findings suggest that extraembryonic tissues such as the placenta and yolk sac provided permissive environments that enabled the retention, expression and functional domestication of virus-derived sequences. Once the placenta itself was established through viral gene integration, it may in turn have acted as a powerful driver of eutherian evolution through recurrent acquisition and co-option of additional virus-derived genes—a process we refer to as “placenta-driven evolution.” This perspective offers a unified framework in which viral gene acquisition is viewed as a key driver of genomic innovation, tightly intertwined with the emergence of viviparity, subsequent divergence at the marsupial–eutherian split, and continued diversification of placental structure and function across eutherian lineages. Full article

Background and Clinical significance: Cowden syndrome is an autosomal dominant disorder caused by germline loss-of-function mutations in the PTEN tumor suppressor gene. It is characterized by multiple hamartomas and an increased lifetime risk of malignancies affecting the breast, thyroid, endometrium, and gastrointestinal (GI) tract. Pediatric presentations may include macrocephaly, scrotal tongue, and intellectual disability. Gastrointestinal involvement is frequent, with juvenile-like hamartomatous polyps occurring in at least half of patients and distributed throughout the GI tract, posing a risk for malignant transformation. Early diagnosis and surveillance are crucial for improving patient outcomes. Case Presentation: We report a case of a 10-year-old Caucasian female with Cowden syndrome, with a history of a malignant germ cell tumor of the ovary consisting of a yolk sac tumor and low-grade immature teratoma diagnosed at age six, and thyroidectomy at age nine. The patient has mild intellectual disability. Routine radiological surveillance revealed a right colon intraluminal mass, prompting referral for pediatric gastroenterology evaluation. Endoscopy identified multiple polyps throughout the colon, stomach, and small intestine. Polypectomy of larger lesions was performed, and histopathology confirmed juvenile-like hamartomatous polyps without dysplasia or malignancy. This case highlights the necessity of comprehensive gastrointestinal evaluation in pediatric Cowden syndrome patients. Endoscopic surveillance is essential for early detection and management of polyps. Conclusions: Given the multisystem involvement and elevated cancer risk associated with PTEN mutations, a multidisciplinary approach that includes genetic counseling, dermatologic evaluation, and ongoing oncologic monitoring is recommended. Increased awareness of gastrointestinal manifestations enables timely intervention and may reduce morbidity and mortality in this high-risk population. Full article

Erythro-myeloid progenitors (EMPs) originate from the haemogenic endothelium in the yolk sac via an endothelial-to-haematopoietic transition (EHT) to generate blood and immune cells that support embryo development. Yet, the transitory nature of EHT and the limited availability of molecular markers have constrained our understanding of the origin, identity, and differentiation dynamics of EMPs. Here, we have refined the annotation of yolk sac haemato-vascular populations in publicly available single-cell RNA sequencing (scRNAseq) datasets from mouse embryos to identify novel molecular markers of haemogenic endothelium and EMPs. By sub-clustering key cell populations followed by pseudotime analysis, we refined cluster annotations and then reconstructed differentiation trajectories. Subsequent differential gene expression analysis between clusters identified novel cell surface markers for haemogenic endothelial cells (Fxyd5 and Scarf1) and EMPs (Fcer1g, Tyrobp, and Mctp1). Further, we have identified candidate signalling and metabolic pathways that may regulate yolk sac haematopoietic emergence and differentiation. The specificity of FXYD5, SCARF1, and FCER1G for haemogenic endothelium and EMPs was validated by immunostaining of the mouse yolk sac. These insights into the transcriptional dynamics in the yolk sac should support future investigation of EHT and haematopoietic differentiation during early mammalian development. Full article

The speckled smooth-hound Mustelus mento is an endemic coastal shark from the southeastern Pacific, currently listed as “Critically Endangered” due to intense fishing pressure and the absence of species-specific management across its distribution range. Between November 2021 and October 2023, 925 individuals were examined from artisanal landings in northern Chile to describe their reproductive biology and embryonic development characteristics. The total length ranged from 27.6–159.3 cm in females and 14.2–165.0 cm in males, with a sex ratio of 1:1.2, which was slightly biased towards females. The estimated size at 50% maturity was 53.6 cm for females and 48.7 cm for males, with 70.6% of females and 66.0% of males caught below these thresholds, indicating a predominance of immature individuals in landings. Nine gravid females (106–139 cm) contained 71 embryos, which were classified into five developmental stages (encapsulated ovum, early organogenesis, fin differentiation, pigmentation and growth, and pre-partum) based on their external morphology and yolk sac reduction. The litter size ranged from 4 to 12 embryos, and the estimated size at birth was 13–14 cm in length. Embryos were recorded only during the summer months, suggesting a seasonal reproductive cycle with parturition in the early autumn. The persistent yolk sac connection throughout development and the absence of placental structures confirm that M. mento exhibits aplacental viviparity. These results document the first population-level description of the reproductive biology of M. mento, redefine its reproductive mode, and provide baseline information essential for implementing species-specific management and conservation measures in Chilean waters. Full article

In viviparous teleosts, the lack of oviducts defines intraovarian gestation, with the ovary being the site for oogenesis but also the site for insemination, fertilization, and gestation. Consequently, intraovarian gestation is a complex and exceptional type of reproduction among vertebrates. The analysis of the morphological and physiological components of intraovarian gestation documents the evolutionary process of nutrition in viviparous species. Two types of embryonic nutrition may occur during gestation: (a) lecithotrophy, when most nutrients for the embryo come from the abundant yolk stored during oogenesis, and (b) matrotrophy, when nutrients for the embryo with scarce yolk must be obtained during gestation by additional maternal provisioning, developing a placenta. Then, investment of maternal nutrients for the embryo is greater during oogenesis in lecithotrophic species, and investment of maternal resources for the nutrition of the embryo is greater during gestation in matrotrophic species. Microscopic techniques allow for proper observation of maternal and embryonic structures involved in both types of nutrition during the development of embryos. Specifically, we focused on the morphology of placental structures associated with embryonic nutrition at different stages of development, which are the yolk sac and the pericardial sac. The oocytes of Poecilia latipinna contain a large amount of yolk (an average oocyte diameter of 1.9 mm); in contrast, the oocytes of Heterandria formosa contain extremely reduced amounts of yolk (an average oocyte diameter of 0.4 mm). Therefore, these species represent appropriate models for studying the strategy of two different types of embryonic nutrition, lecithotrophy and matrotrophy, in viviparous teleosts. Full article

Background/Objectives: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor and cognitive impairments due to dopaminergic neuron loss. The neurotoxin MPTP is commonly used to model PD, as it selectively targets these neurons. Quercetin (QU), a flavonoid with antioxidant properties, has shown neuroprotective potential, but its poor solubility limits clinical application. Nanoemulsions (NEQU) have emerged as a strategy to enhance its bioavailability and efficacy. Methods: To evaluate the neuroprotective and antioxidant effects of QU and NEQU, zebrafish larvae were exposed to MPTP (50 µM) and assessed for survival, locomotion (total distance traveled), morphological parameters, reactive oxygen species (ROS), lipid peroxidation (via MDA), and reduced glutathione (GSH) levels. Results: Only NEQU pre-treatment reversed MPTP-induced locomotor deficits. Both QU and NEQU (2.5 µM) significantly reduced ROS production and lipid peroxidation, with no effect on GSH levels. Notably, MPTP exposure led to a significant reduction in head size, an unprecedented finding in zebrafish PD models, indicating neurotoxicity. Morphometric analysis showed no change in total body length. However, MPTP significantly decreased swim bladder size and increased yolk sac size. Treatment with QU and NEQU attenuated these swim bladder alterations; no significant differences were observed in other parameters. Conclusions: These findings suggest that quercetin, particularly when nanoencapsulated, is a promising candidate for further development as a therapeutic agent to mitigate PD-related neurodegeneration. Full article