Search Results (135)

Microglia, as the immune guardians of the central nervous system (CNS), have the ability to maintain neural homeostasis, respond to environmental changes, and remodel the synaptic landscape. However, persistent microglial activation can lead to chronic neuroinflammation, which can alter neuronal signaling pathways, resulting in accelerated cognitive decline. Phosphoinositol 3-kinase (PI3K) has emerged as a critical driver, connecting inflammation to neurodegeneration, serving as the nexus of numerous intracellular processes that govern microglial activation. This review focuses on the relationship between PI3K signaling and microglial activation, which might lead to cognitive impairment, inflammation, or even neurodegeneration. The review delves into the components of the PI3K signaling cascade, isoforms, and receptors of PI3K, as well as the downstream effects of PI3K signaling, including its effectors such as protein kinase B (Akt) and mammalian target of rapamycin (mTOR) and the negative regulator phosphatase and tensin homolog (PTEN). Experiments have shown that the overproduction of certain cytokines, coupled with abnormal oxidative stress, is a consequence of poor PI3K regulation, resulting in excessive synapse pruning and, consequently, impacting learning and memory functions. The review also highlights the implications of autonomously activated microglia exhibiting M1/M2 polarization driven by PI3K on hippocampal, cortical, and subcortical circuits. Conclusions from behavioral studies, electrophysiology, and neuroimaging linking cognitive performance and PI3K activity were evaluated, along with new approaches to therapy using selective inhibitors or gene editing. The review concludes by highlighting important knowledge gaps, including the specific effects of different isoforms, the risks associated with long-term pathway modulation, and the limitations of translational potential, underscoring the crucial role of PI3K in mitigating cognitive impairment driven by neuroinflammation. Full article

Estrogen plays some important roles in many physiological processes in animals. This hormone is used as a type of medication for humans and animals, including fish, but is associated with serious side effects and environmental persistence, which has led to a growing interest in phytoestrogens as an alternative. Phytoestrogens are compounds derived from plants that are structurally similar to estrogen and may exhibit similar behavior in the body. To date, no studies have investigated the activity of phytoestrogens in relation to the maturation of eels. In the present study, we investigated the effects of ten different plant extracts on vitellogenin (vtg) and estrogen receptor (esr1, esr2) gene expression in eel hepatocytes. As a result, Schisandra and Astragalus extracts induced higher levels of vtg mRNA expression compared to the other extracts. However, increased esr mRNA expression was observed only in the Schisandra and soybean extract-treated groups. The phytoestrogens known to be present in Schisandra and Astragalus were analyzed using HPLC. Schizandrin, gomisin A, and gomisin N were detected in Schisandra extract, and calycosin and formononetin were detected in Astragalus extract. We then examined whether these phytoestrogens could induce vtg mRNA expression in eel hepatocytes. As a result, gomisin N and formononetin significantly induced vtg mRNA expression. In conclusion, among the 10 plant extracts treated in this study, Schisandra and Astragalus extracts induced estrogenic activity in eel hepatocytes. These extracts were found to contain phytoestrogens, with gomisin N and formononetin identified as the primary active components responsible for the observed estrogenic activity in eel hepatocytes. Full article

The skin and its products, such as the mucus, represent an important defense mechanism against infection by pathogens. Various environmental conditions can alter mucus composition and/or cells embedded in this matrix. The analysis of skin mucus is considered a useful method to evaluate the biological response of fish to stimuli. The mucus and cells can be considered suitable non-invasive biomarkers. With this preliminary study, an antibacterial capacity method was applied to cutaneous mucus samples of a European eel population. This standardized method highlighted the ability of the mucus to significantly counteract the proliferation of two bacteria, the opportunistic pathogen Aeromonas hydrophila and the primary pathogen Aeromonas salmonicida. The cytological method using skin scraping has proven to be a useful non-invasive tool, having allowed the highlighting of the two most represented cellular populations of the cutaneous covering, the epidermal cells and the goblet cells, in combination with mucous strands. Cytological findings did not disclose pathologic elements in the mucus. A broader use of these two non-invasive microbiological and cytological methods can provide useful information on fish health, indirectly contributing to the conservation of the species. Full article

Previous studies performed on the European eel Anguilla anguilla showed changes in the morphology and physiology of several tissues after exposure to environmental cocaine concentrations. To better understand the model through which cocaine produced its effects on these tissues, we investigated whether there were alterations in the expression of cannabinoid CB1 receptor (CB1R). Indeed, the endocannabinoid system, and CB1R, regulate neurotransmission, neurodevelopment, embryonic development, reproduction, and the activity of the gastrointestinal system. CB1R has been detected in nervous and peripheral tissues in mammals, and orthologues of the mammalian CB1R are found throughout vertebrates including chicken, turtle, frog, and fish. Therefore, samples of gut, kidney, ovary, muscle, liver, skin, and gills from cocaine-exposed and non-exposed eels were processed for routine histology. Immunohistochemical analysis was carried out to evaluate the immunolocalization of the CB1R. Our results showed for the first time (1) the presence of CB1R in the peripheral tissues of the eel, and (2) statistically significant differences in the localization of CB1R in the gut, kidney, ovary, muscle, and liver of the eels exposed to cocaine, compared to controls. These results demonstrate the involvement of CB1R in cocaine effects and suggest its potential role as a biomarker of tissue alteration. Full article

Anxiety disorders are among the most common psychiatric conditions that significantly impair one’s quality of life and place a significant burden on healthcare systems. Conventional treatments have certain restraints, such as potential side effects and limited efficacy. Τhe underlying pathophysiological mechanisms of anxiety are not fully understood. A comprehensive literature search was performed in MEDLINE and Scopus databases for original English-language articles published between January 2014 and December 2024. Study selection, data extraction, and screening were independently carried out by multiple investigators using predefined criteria. Our review aimed to help better comprehend the molecular basis of anxiety, focusing on the hypothalamic–pituitary–adrenal (HPA) axis, serotonergic signaling, and gamma-aminobutyric acid (GABA) neurotransmission. In addition, we addressed the role of epigenetics and pharmacogenomics in personalized treatment. Although novel anxiety treatments are promising, they are predominantly preclinical and highly heterogeneous, which poses a challenge to achieving reliable therapeutic efficacy. Our findings could potentially contribute to the development of new therapeutic interventions. Further research is warranted, especially in human subjects, with an aim to combine genetic and epigenetic profiles to refine treatment approaches and develop innovative therapeutics. Full article

Background: Depression constitutes a major public health issue, being one of the leading causes of the burden of disease worldwide. The risk of depression is determined by both genetic and environmental factors. While genetic factors cannot be altered, the identification of potentially reversible environmental factors is crucial in order to try and limit the prevalence of depression. Aim: A cross-sectional, questionnaire-based study on a sample from the multicultural region of Thrace in northeast Greece was designed to assess the potential association of depression with several sociodemographic characteristics, lifestyle, and health status. The study employed four machine learning (ML) methods to assess depression: logistic regression (LR), support vector machine (SVM), XGBoost, and neural networks (NNs). These models were compared to identify the best-performing approach. Additionally, a genetic algorithm (GA) was utilized for feature selection and SHAP (SHapley Additive exPlanations) for interpreting the contributions of each employed feature. Results: The XGBoost classifier demonstrated the highest performance on the test dataset to predict depression with excellent accuracy (97.83%), with NNs a close second (accuracy, 97.02%). The XGBoost classifier utilized the 15 most significant risk factors identified by the GA algorithm. Additionally, the SHAP analysis revealed that anxiety, education level, alcohol consumption, and body mass index were the most influential predictors of depression. Conclusions: These findings provide valuable insights for the development of personalized public health interventions and clinical strategies, ultimately promoting improved mental well-being for individuals. Future research should expand datasets to enhance model accuracy, enabling early detection and personalized mental healthcare systems for better intervention. Full article

Ballast water has become a significant vector for the global spread of non-indigenous aquatic species. These species may cause severe ecological disruption and economic losses when introduced into new environments. Traditional monitoring techniques often lack the sensitivity and efficiency required for early monitoring, hindering timely and effective management. In this study, we used environmental DNA (eDNA) technology to assess fish diversity and identify non-indigenous fish species in ballast water samples collected from 14 international vessels entering Dongjiakou Port, China. Genetic evidence of five non-indigenous fish species was monitored, including two recognized invasive species (Lates calcarifer and Anguilla anguilla). Among all groups, samples from Group B (V2, V3, V6, V8) exhibited the highest diversity of non-indigenous species, suggesting regional differences in species composition that may reflect source port biodiversity. These findings highlight the utility of eDNA-based monitoring not only for early detection of potentially non-indigenous taxa but also for capturing biogeographic patterns associated with global maritime traffic. By demonstrating the effectiveness of this approach at an international port, this study contributes a scientific foundation for both local biodiversity conservation and broader ecological surveillance, offering valuable insights for the ongoing development of ballast water management strategies worldwide. Full article

The Lima River in northern Portugal serves as a vital habitat for diadromous fish species, yet it remains one of the least studied aquatic systems in the region. This study investigates the ecology and biology of key diadromous fish populations, including sea lamprey (Petromyzon marinus), shads (Alosa alosa and Alosa fallax), trout (Salmo trutta), and European eel (Anguilla anguilla), during their reproductive migration and riverine periods. A total of 3242 individuals from 15 species were sampled, with native species accounting for 51.1% of the catch. Results revealed significant differences in size and weight of lampreys, with individuals from the Lima River being significantly smaller than those from regional rivers such as the Minho and Mondego. Shad populations showed a high proportion of hybrids (33.8%), suggesting extensive hybridization between A. alosa and A. fallax. Analysis of trout stomach contents revealed a diverse diet dominated by insects (66.9%), crustaceans (6.8%), and fish (6.8%), but also an alarming presence of plastic debris (1.1%), highlighting potential pollution problems. For European eels, this study marks the first record of the invasive swim bladder parasite Anguillicola crassus in the Lima River, with 84.8% of eels sampled showing moderate to severe swim bladder damage. These findings contribute to a deeper understanding of diadromous fish ecology and emphasize the importance of conservation efforts in estuarine systems worldwide. Full article

Replacing fishmeal (FM) with plant-based protein sources remains a significant challenge, particularly for carnivorous fish. This study investigates the effect of dietary Lentinus edodes fermentation (LEF) supplementation on Japanese eel (Anguilla japonica) fed with fermented soybean meal (FSM) as a partial FM replacement. The positive control consisted of 64% FM (Con), and the negative control (FSM group) included 52% FM plus 12% FSM. Two experimental diets were formulated by adding 2% LEF (LEF2 group) and 3% LEF (LEF3 group) to the negative control diet. The experimental diet was administered to Japanese eels weighing 62.50 ± 2.14 g for 12 weeks. The experimental fish were randomly assigned to four groups, with three replicates of 100 fish per group. The results indicated that growth performance and feed efficiency were significantly reduced in the FSM group, but were significantly improved by LEF supplementation (p < 0.05). LEF supplementation did not significantly affect muscle crude fat and protein content compared to the FSM group (p > 0.05), but significantly increased muscle amino acid content and levels of certain fatty acids (linoleic acid, γ-linolenic acid, eicosatrienoic acid, DHA) (p < 0.05). LEF supplementation reduced serum TC and LDL-C levels, increased HDL-C levels, significantly increased CAT and T-SOD activities, and reduced MDA levels in both serum and liver (p < 0.05). ALT and AST activities were significantly elevated in the FSM group, accompanied by liver histological abnormalities, which were improved by LEF supplementation. LEF supplementation increased the thickness of the muscularis, villus height, and goblet cell count in the intestine (p < 0.05). Compared to the control, the FSM group significantly upregulated spleen tnf-α gene expression and downregulated the expression of anti-inflammatory factors (ifn-α, ifn-γ, socs1, mavs). LEF supplementation ameliorated the reduced immunocompetence induced by FM replacement with FSM by enhancing the expression of immune-related genes (irak4, ifn-α, ifn-γ, irf3, irf11, socs1, mavs, traf3) in the spleen. These results suggest that the beneficial effects of LEF supplementation on growth performance and feed efficiency may be attributed to its improvement of liver damage and intestinal histology, as well as its enhancement of antioxidant capacity and immunity. Full article

Background: Amoxicillin (AMOX) is widely used in aquaculture for bacterial infections due to its efficacy and safety. Despite official approval for select species, off-label use is common. This study evaluated the antibacterial efficacy and residue depletion of AMOX in five aquaculture species: olive flounder (Paralichthys olivaceus), rainbow trout (Oncorhynchus mykiss), Japanese eel (Anguilla japonica), black rockfish (Sebastes schlegelii), and Israeli carp (Cyprinus carpio). Methods: Fish were administered AMOX orally at 40 mg/kg and 80 mg/kg for seven days. Antibacterial efficacy was assessed by bacterial load reduction and survival rates following artificial infection. Residue depletion was analyzed using HPLC–MS/MS to determine the time required for AMOX levels to fall below the maximum residue limit (MRL, 0.05 mg/kg). Results: AMOX, at 40 mg/kg, significantly reduced bacterial loads in olive flounder, rainbow trout, and Japanese eel (p < 0.05), while Israeli carp exhibited a limited response (p = 0.54). Black rockfish showed moderate efficacy (RPS 72.7%) but increased mortality at 80 mg/kg. Residue levels fell below the MRL within 10 days for all species except Israeli carp (~30 days). Conclusions: These findings highlight species-specific differences in AMOX efficacy and residue depletion rates, emphasizing the necessity of tailored dosing regimens and withdrawal periods to ensure optimal therapeutic outcomes and food safety compliance in aquaculture. Further pharmacokinetic studies are needed to refine dosing strategies, particularly for species with extended residue retention and potential dose-dependent adverse effects. Full article

Cities in plain areas have small slopes at the bottoms of rivers, with weak hydrodynamics, heavy pollution and poor self-purification capacities for the restoration of biological habitats. Hydrodynamic and water quality improvements are effective means for the ecological restoration of plain urban rivers. The potential for fish habitat resilience in a typical urban river network plain (more than 130 river sections) in the Dianbei part of China was studied. The tolerant fish, Carassius auratus (C. auratus), and the sensitive fishes Trachidermus fasciatus (T. fasciatus) and Anguilla japonica (A. japonica), were selected as the protection targets, and hydrodynamic factors, river morphology and water quality factors were chosen as environmental indicators. With the fish habitat suitability index, a fish habitat resilience potential evaluation model was established. The response of the habitat resilience potential index (HRPI) to hydrodynamic regulation was subsequently analyzed, and the HRPI indicated an increased habitat resilience potential with its value increasing from 0 to 1. Overall, the resilience potential of tolerant fish species was greater than that of sensitive species in the Dianbei. For the HRPI of C. auratus adults (tolerant species), approximately 62.8% of the river sections were above 0.6 (high resilience level) and were concentrated in the northwest area of the river network. While for the resilience potential of A. japonica adults and T. fasciatus adults (sensitive species), only 60% of the river sections exhibited moderate resilience level (HRPI > 0.5). The average dimensionless habitat resilience potential index (AHRPI) was enhanced by water diversion with its values increased by 10.3%, 9.3% and 12.7% for C. auratus adults, T. fasciatus adults and A. japonica adults, respectively. The habitat resilience potential of C. auratus changed little during the spawning period, which indicated that the effect of hydrodynamic regulation was limited. This study provides a scientific basis for managers to restore urban river network habitats in plain areas. Full article

The nematode Spinitectus inermis (Zeder, 1800), a specific gastrointestinal parasite of Anguilla anguilla, has been recorded for the first time in the Italian Peninsula. The study was conducted in the Mesima River, located in the southwestern part of the Calabria region (southern Italy). Over a five-month period, 162 specimens of European eel were sampled, revealing an overall prevalence of 47.53%, a mean intensity of 9.51 (±13.88), and a mean abundance of 4.55 (±10.69). The nematode was present throughout the five months analyzed, with prevalence rates ranging from 32.0% to 57.14%. The overall prevalence in the Mesima River was higher than in most previous studies, and the mean abundance of infection was also higher. The highest prevalence of infection was observed in September (56.7%), October (57.14%), November (48.57%), and December (40.54%), with the lowest in March (32.0%). In conclusion, Spinitectus inermis appears to be well established in the eel population of the Mesima River, exhibiting high prevalence and intensity year-round despite ecological variations, though its intermediate hosts remain unknown. Full article

Eel (Anguilla japonica) is an important and valuable food fish in East Asia and its by-products have been reported to include bioactive and profitable components. This study aimed to extract, characterise, and compare the structure and properties of acid-soluble collagens (ASCs) and pepsin-soluble collagens (PSCs) from the skin and bone of eel (Anguilla japonica), providing insights into their composition, structure, and properties for various applications. The yields of ASC-S (from skin), PSC-S (from skin), ASC-B (from bone), and PSC-B (from bone) were 12.16%, 15.54%, 0.79%, and 1.34% on a dry weight basis, respectively. Glycine, the dominant amino acid, accounted for 16.66% to 22.67% of total amino acids in all samples. SDS-PAGE and FTIR analyses showed the typical triple-helical structure of type I collagen with slight variations in molecular order in extract and intermolecular cross-linking between skin and bone collagens. The denaturation temperature (T_max1) measured by differential scanning calorimetry (DSC) is 81.39 °C and 74.34 °C, respectively, for ASC-B and ASC-S. Bone collagen has higher thermal resistance than skin collagen. Surface morphology imaged using a scanning electron microscope (SEM) showed that the bone collagen had a denser network structure, whilst the skin collagen was more fibrous and porous. The findings suggest that eel-derived collagens from skin and bone can serve as potential alternatives in the food, cosmetic, and healthcare industries. Full article

According to European reports, the population of Anguilla anguilla has declined to unsafe biological limits in most areas and current fisheries are unsustainable. Indeed, the European eel has been listed as a critically endangered species since the 1970s and has been on the IUCN Red List of Threatened Species since 2010. Glass eel fisheries in Europe are very limited, but illegal catches and international parallel trade are major threats to eel stocks due to their high commercial value. The main hypothesis of this study is that glass eels from each estuary have unique chemical profiles according to the ecological quality of the habitat. These unique chemical fingerprints were assessed using Chemical Integrating Approaches (CIA) based on multi-element (macro, trace and ultra-trace metals), global metabolome and stable isotope analyses. Thus, CIA are intended to be an effective chemical “weapon” to (i) fingerprint wild glass eels; (ii) fingerprint captive glass eels; (iii) authenticate and trace glass eels; and (iv) combat the illegal trade in juvenile European eels. The results of this study showed that Zn and Ni can fingerprint the chemical profiles of wild and captive glass eels and their geographical origin. In the same vein, metabolomes such as Butyric acid 4-vinylphenyl ester, N-(3-carboxypropanoyl)-Met, 2-(4-Methylphenyl)acetamide, N-formyl-glutamic acid, 3-Hydroxy-2-(3-methylbutanoylamino)propanoic acid, 4-Dodecylbenzenesulfonic Acid, Arginine and Pyrazole and the stable isotope 15N show potential as a chemical tools for glass eel traceability. Full article

The ecological, cultural and economic importance of freshwater eels, coupled with declining wild populations, drives the need for artificial propagation of these fish. Despite the closure of the lifecycle in captivity over a decade ago, numerous bottlenecks still prevent production at a commercially viable scale. Focusing on the key event of nutrient accumulation, we employed hypophysation over a 10-week period with biweekly sampling of female New Zealand shortfinned eels (Anguilla australis). Slotblots, colorimetric lipid/cholesterol assays, fast protein liquid chromatography and radioimmunoassay were used to assess aspects of blood chemistry. The lack of any trend in triglyceride and apolipoprotein B levels in plasma over time, combined with a significant reduction in cholesterol concentrations and a 10-fold increase in vitellogenin levels, confirmed a shift from low-density lipoprotein dominance—usually associated with lipid uptake and early oogenesis—to an abundance of high-density lipoproteins linked to vitellogenesis. The ongoing presence of 11-ketotestosterone in the circulation and the increase in 17β-estradiol levels reinforced the importance of steroids in mediating the gonadotropic signal associated with hypophysation. We conclude that the accumulation of both vitellogenin and apolipoprotein-B-associated lipids is essential for nutrient accumulation in eel oocytes during artificial induction of maturation. Full article