XcpQ from Pseudomonas aeruginosa: A potential vaccine candidate with immunogenic properties in zebrafish.

Embryonic exposure to Bisphenol S causes long-term social behavioural alterations in adult zebrafish (Danio rerio).

Fitness in novel environments: Bisphenol S and warming reduce energy efficiency, reproductive success, and movement across generations in zebrafish (Danio rerio).

Nucleotide (NT) supplementation is an efficient practice for enhancing growth and immune performance in farmed aquatic species. However, the NT mode of use, optimal dosage and metabolic effects in different species remain poorly understood. This study investigated the effects of exposing zebrafish ( Danio rerio ) and gilthead seabream ( Sparus aurata ) embryos and larvae to different concentrations of a blend of NTs directly through the water. Embryos and larvae were exposed for 96 h, starting at 24 h post fertilisation. The developmental and physiological parameters assessed included survival, hatching rate, morphology, swimming behaviour, expression of growth-related genes, and macrophage cell status. In zebrafish, survival and hatching rate were unaffected up to 200 mg L −1 (>90%). Morphological analysis revealed that zebrafish exposed to NT at 20–40 mg L −1 exhibited the most significant enhancements in growth (+5% compared to controls), while behavioural tests and gene expression analysis indicated increased swimming activity and significant modulation of key growth-related genes at 10 mg L −1 . Furthermore, immunological assays demonstrated a significant increase in the prevalence of pro-healing M2 macrophages in the gut of larvae at this NT concentration. In gilthead seabream, NT-treated larvae at 10 mg L −1 exhibited a significant increase in standard body length (+4% compared to controls), with no adverse effects on survival or hatching rate up to this level (>75%). Overall, these findings demonstrate that NT exposure promotes larval growth and modulates immune and metabolic activity in zebrafish and gilthead seabream, supporting the application of NT blends as sustainable bioactive additives in aquaculture. • Waterborne nucleotide enhance zebrafish and gilthead seabream larval growth. • Nucleotide exposure boosts zebrafish swimming activity and expression of growth-related genes. • Nucleotides increase pro-healing M2 macrophages in the gut of transgenic zebrafish. • Zebrafish serves as an efficient model for testing bioactive compounds in aquaculture.

Synergistic effect of carboxymethyl chitosan and phloroglucinol against rotenone induced Parkinson's disease in zebrafish model.

Oxidative damage and intestinal microbial imbalance induced by polystyrene microplastics and cadmium in zebrafish (Danio rerio)

Cyhalothrin induced neurotoxicity via disrupting NF-κB and L-glutamate signaling and functions in zebrafish (Danio rerio).

Developmental and systemic toxicity of the triazole fungicide tetraconazole in zebrafish: Integrated evidence from ER stress, apoptosis, and metabolomic disruption.

Major depressive disorder (MDD) is a highly prevalent and disabling psychiatric condition, increasingly recognized as a systemic disorder involving central and peripheral pathophysiological alterations. In this study, we used a multidimensional approach using zebrafish (Danio rerio) exposed to an unpredictable chronic stress (UCS) protocol as a model of MDD, to unravel the plasticity of the lipidome in this mental disorder. Behavioral analyses revealed a reduction in sociability and locomotor activity in stressed animals, accompanied by significantly elevated cortisol levels. Fatty acid profiling demonstrated a decrease in n-3 (omega-3) polyunsaturated fatty acids (PUFA) and an increase in n-3 (omega-6) PUFA, which was more evident in the brain than in the muscle. After UCS, lipidomic analysis revealed a remodeling of the brain lipid profile, including the modulation of several phospholipid and sphingolipid species that may impact cell membrane properties and cause neuronal dysfunction. Some of these species have been previously correlated with neuroinflammation and impaired neurotransmission. An increase in plasmalogen phospholipids, well-known endogenous oxidant signaling molecules, suggests a dysregulation of the redox state. In muscle, lipidomic alterations were characterized by elevated levels of acylcarnitines, indicative of altered mitochondrial energy metabolism, and ceramides, well-known pro-inflammatory and pro-apoptotic molecules. This study highlights the relevance of lipidomic plasticity in the pathophysiology of MDD, associated with behavioral effects similar to MDD symptoms.

Combined effects of environmentally relevant glyphosate concentration and elevated temperature on zebrafish embryotoxicity.

Identification of Fluoro-methoxy-phenyl-substituted N-sulfonylpiperidine-mono-spiro-1,2,4,5-tetraoxanes as Multispecies-targeting Molecules.

A simple oral STZ/alloxan-induced diabetic zebrafish model for chronic wound healing and therapeutic assessment.

Poisonous plants are traditionally used for fishing in several parts of North-East India; however, their toxicological effects on aquatic organisms require systematic evaluation. Derris taiwaniana is used locally as an ichthyotoxic plant and is also reported in traditional medicinal practices. The present study assessed the acute toxicity and genotoxic potential of the aqueous seed extract of Derris taiwaniana (AEDT) in adult zebrafish (Danio rerio). Adult zebrafish were exposed to different concentrations of AEDT under a 96 h semi-static exposure system, and mortality was recorded at 24, 48, 72 and 96 h to estimate lethal concentration values. Genotoxicity was evaluated using the micronucleus assay in peripheral blood erythrocytes after 96 h of exposure to selected AEDT concentrations. AEDT exposure produced concentration- and time-dependent mortality in adult zebrafish. The calculated LC50 values were 3.662 mg/L at 24 h, 2.792 mg/L at 48 h, 2.448 mg/L at 72 h and 2.214 mg/L at 96 h. Exposed fish also showed behavioural signs of distress, including opercular hyperventilation, erratic swimming, surface gasping, loss of equilibrium and sinking before death. In the micronucleus assay, AEDT caused a dose-dependent increase in micronucleated erythrocytes compared with the negative control. The highest tested AEDT concentration, 2.4 mg/L, produced a micronucleus frequency of 6.52 ± 0.47%, while the negative control showed 0.47 ± 0.08%. These findings indicate that the aqueous seed extract of D. taiwaniana has acute toxic and genotoxic effects in adult zebrafish under the experimental conditions used. Further studies are required to identify the active toxic constituents and clarify the mechanisms involved.

Zebrafish (Danio rerio) is a powerful vertebrate model organism with strong genetic and physiological similarity to humans, yet its use in large-scale transcriptomic research remains constrained by incomplete gene annotations, inefficient ribodepletion methods, and limited transcript-level resolution. To tackle these challenges, we applied CapTrap-seq, a platform-agnostic long-read RNA sequencing approach combining cap-trapping with oligo(dT) priming to selectively capture 5'-capped, full-length transcripts, to zebrafish developmental stages and adult tissues. We further introduce a size-selection step that substantially improves recovery of longer RNA molecules without compromising quantitative accuracy. Benchmarking against the template-switching oligo (TSO) approach demonstrated that CapTrap-seq enables accurate and reproducible transcript reconstruction in a non-mammalian system without requiring external ribodepletion or validation resources. Comparative analysis across multiple long-read catalogues showed that CapTrap-seq detected the largest number of biologically and clinically relevant genes, including oxidative phosphorylation, cardiac, and Online Mendelian Inheritance in Man (OMIM) disease genes, while revealing extensive isoform diversity absent from current annotations. Analysis of the carmn and dancr lncRNA loci further demonstrated the ability to resolve complex splicing landscapes, uncovering novel full-length isoforms with distinct domain architectures not represented in existing zebrafish reference annotations. CapTrap-seq thus emerges as a robust, genome-agnostic framework for high-quality transcriptome characterisation in zebrafish and other under-annotated species, with broad implications for functional genomics and translational research.

Integrative QSAR modelling of multi-species pesticide baseline (narcosis) toxicity.

Zebrafish (Danio rerio) is used as a model to study adrenergic signaling and pigment cell development because their genetic structure matches human genetics and enables advanced scientific research methods. Researchers use zebrafish to conduct their studies in three different research areas which include cellular signaling studies and toxicology research and pharmacology investigations and translational scientific work. Hormonal processes through alpha-MSH MCH and melatonin interact with each other to regulate pigment distribution. The GPCR-mediated pathways initiate melanosome aggregation and dispersion processes through catecholamine binding which leads to cyclic AMP (cAMP) and calcium (Ca2+) pathway activation. The adrenergic signaling system adjusts to different environmental factors and endocrine disruptors which then creates changes to both pigmentation and behavioral patterns. The review examines how adrenergic receptor signaling works in the body and demonstrates its role in controlling melanophore functions. This review underscores the importance of adrenergic signaling in zebrafish as a model system that bridges fundamental cellular biology with translational applications in human health, drug development, and environmental toxicology, offering valuable perspectives for future interdisciplinary research.

Multiparameter optimization of a previously identified class of inhibitors of the energy-coupling factor (ECF) transporters enabled the confirmation of in vivo efficacy. ECFs are a class of transmembrane proteins that play a vital role in the active translocation of essential nutrients across cell membranes and are therefore important in the fight against antimicrobial resistance. Aiming to improve the drug-like properties of our inhibitory class, we performed a focused structure-activity relationship study around the Eastern part of our starting molecule 3 by exploiting click chemistry. Our multiparameter optimization resulted in compounds with enhanced metabolic stability and solubility, potent activity against both a panel of Gram-positive bacteria, and against the ECF transporters. We further demonstrate rapid bacterial killing using Enterococcus faecium as a model organism and confirmed in vivo efficacy of the best compounds in Galleria mellonella larvae and Danio rerio (zebrafish) infection models, highlighting the therapeutic potential of our approach.

In many research studies, the handling and procedures performed can generate stress and require the use of anesthesia or sedation. In this sense, plant-based extracts named essential oils have emerged as potentially effective and environmentally safe anesthetic/sedative options. Here, we sought to evaluate the essential oil of Varronia curassavica (VCEO) as an anesthetic/sedative ingredient. Here, the anesthetic and sedative capabilities of the VCEO using adult zebrafish (Danio rerio). The anesthetic induction was performed under four different concentrations (100, 200, 400, and 600 mg L-1), followed by evaluation of recovery time; furthermore, a 3 h long exposure was performed for sedative testing, where fish were exposed for 3 h at three different concentrations (50, 80, and 100 mg L-1) under a superpopulation condition, such as those faced during transport. To assess stress, we collected whole-body cortisol from each individual after each exposure. The concentrations of 400 and 600 mg L-1 induced anesthesia (S4) but promoted excessive recovery times; on the contrary, they reduced the cortisol levels of the fish compared with the positive and negative controls. In the sedative testing (3 h long exposure), the animals exposed to 50 mg L-1 remained in S2 stage from the first 10 min, and those exposed to 80 mg L-1 after 20 min. The 100 mg L-1 induced stage S3a. There were no significant changes in cortisol levels observed at these concentrations. Limitations include measurement of whole-body cortisol at a single endpoint and the consistently slower induction and recovery with VCEO compared with a reference anesthetic MS-222, a property that constrains its practical use and warrants further dose-response, time-course, and recovery-optimization studies. Therefore, VCEO appears to be a promising anesthetic and sedative alternative, effective and plant-based, without increasing the physiological stress of the animals.

Selective serotonin reuptake inhibitors (SSRIs) such as sertraline are used as antidepressants to treat mental disorders such as depression by blocking serotonin reuptake and thus maintaining high serotonin levels. Currently, increased consumption has led to detection of SSRIs in aquatic systems; however, information about their effects on exposed organisms is limited. This study investigated differences in the colonization response by zebrafish (Danio rerio) to sertraline-contaminated environments considering personality traits (shy and bold). Colonization was assessed in terms of success, efficiency, and inhabited time for each sertraline concentration. Fish were tested individually and in groups. In addition, whether these personality traits differed from each other in their olfactory sensitivity to different olfactory stimuli was studied, including sertraline, using the electro-olfactogram (EOG). Bold fish exposed in groups tended to colonize higher concentrations of sertraline than shy fish. These differences were not as significant when fish were exposed individually. Furthermore, analyses in the EOG detected that bold fish reacted between 1.3 and 2.8 times more to all stimuli studied. In contrast, sertraline was not detected by the olfactory system. Varied D. rerio colonization responses to sertraline-contaminated environments reveal specific personality-based vulnerabilities. These findings underscore the importance of integrating behavioral phenotypes into environmental risk assessments for pharmaceuticals.

Organic solvents are routinely used to dissolve poorly water-soluble chemicals in zebrafish-based assays. However, their intrinsic biological activity may confound behavioural endpoints and compromise data interpretation. This study systematically evaluated the effects of seven commonly used laboratory solvents, dimethyl sulfoxide (DMSO), ethanol (EtOH), methanol (MeOH), acetone (Ace), acetonitrile (ACN), isopropanol (IPA), and ethyl acetate (EtOAc), at four concentrations (1, 0.5, 0.1, 0.05%; v/v), on locomotor behaviour of zebrafish Danio rerio larvae at 120h post fertilization. Larval activity was quantified using automated video tracking under alternating light-dark conditions, assessing distance moved, velocity, acceleration, mobility states, and turning behaviour. Behavioural responses were strongly solvent- and concentration-dependent. EtOH, MeOH, Ace, and IPA induced hyperactivity at ≥ 0.5%, while DMSO showed biphasic effects, stimulating activity at 0.5% but suppressing it at 1%. ACN demonstrated a significant inhibitory response even at 0.5%, while EtOAc was tolerated only at ≤ 0.1%. Principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) further revealed coherent behavioural signatures shaped not only by solvent identity and concentration but also strongly by light-dark transitions, underscoring the critical importance of consistent illumination conditions in zebrafish behavioural assays. Overall, ≤ 0.1% of Ace and EtOAc, and ≤ 0.05% of DMSO, EtOH, MeOH, ACN, and IPA did not significantly alter locomotion, suggesting their suitability for zebrafish behavioural assays. These findings establish reference points for solvent selection and concentration thresholds in zebrafish behavioural assays under the specific experimental conditions tested, thereby supporting reproducibility and reliability in scientific research.