BACKGROUND:Benzoxaboroles showed significant antimicrobial efficacy in the past, warranting further investigation. RESEARCH DESIGN AND METHODS:Benzoxaboroles were evaluated for their cytotoxicity on Vero E6 and PBMCs, as well as their embryotoxicity in zebrafish embryos. Benzoxaboroles' impact on C. albicans in planktonic and biofilm was assessed. Advanced microscopy provided insights into C. albicans viability, while RNA-seq identified differentially expressed genes, with docking studies underscoring the potential of benzoxaboroles against fungi. RESULTS:Bis(benzoxazole) analog (2) and Tavaborole effectively inhibited C. albicans, decreasing viability to 80% at 64 µg/mL compared to 60% at 16 µg/mL. The biofilm-inhibiting concentration (BIC50) was 2 μg/mL, leading to a 50% reduction in biofilm activity. 2 exhibited limited morphogenesis, it displayed significantly lower embryotoxicity compared to Tavaborole, with an IC50 greater than 128 μg/mL. 2 maintained approximately 80% viability of VERO E6 at 64 μg/mL. 2 reported an IC50 of 2 μg/mL against PBMCs. RNA-seq revealed upregulation of efflux pumps (MDR) and downregulation of inositol-1-phosphate synthase during benzoxazole treatment. Docking studies confirmed interactions with LeuRS. CONCLUSIONS:Benzoxaboroles exhibited a similar resistance to azoles, which is associated with increased MDR1 and IDH6 levels. Efflux inhibitors for benzoxaboroles were crucial for treating candidiasis and may inspire future antifungal research.

Zebrafish larvae are increasingly used in behavioural pharmacology because of their translational relevance and suitability for anxiety- and stress-related studies. However, it remains unclear whether commonly used behavioural assays and molecular stress markers provide convergent evidence of anxiolytic-like drug activity. This study therefore aimed not to validate a single predictive screening platform, but to assess the concordance and interpretative value of behavioural and molecular endpoints in larval zebrafish anxiety-related drug screening.Reference compounds with established anxiolytic or antidepressant activity, including diazepam, amitriptyline, and fluoxetine, were used to anchor assay performance. TP003, a GABAergic modulator, and three serotonergic psychedelic compounds, DOI, 5-MeO-DMT, and psilocybin, were included to challenge the assays with pharmacologically diverse mechanisms relevant to stress- and anxiety-related responses.Diazepam showed the strongest cross-assay behavioural consistency compatible with an anxiolytic-like profile. However, this response was not accompanied by reduced cortisol levels or straightforward normalisation of stress-related gene expression. Amitriptyline reduced cortisol but produced only partial behavioural effects, whereas DOI affected selected behavioural preference endpoints and transcriptional markers without significantly reducing cortisol. Fluoxetine and 5-MeO-DMT altered locomotor activity in patterns requiring cautious interpretation, as reduced movement may reflect locomotor suppression or sedation rather than anxiolysis alone.These findings indicate that behavioural and molecular endpoints should not be treated as interchangeable measures of a single anxiety construct. Instead, combined behavioural and molecular assessment is most useful as a profiling framework to identify endpoint-dependent responses, detect sedative or nonspecific locomotor confounds, and support more cautious interpretation of putative anxiolytic-like effects in larval zebrafish.

Despite global control efforts, tuberculosis remains the leading infectious cause of death, with rising incidence, pediatric cases, and drug-resistant strains posing major public health challenges. Mycobacteria, including Mycobacterium tuberculosis, possess a lipid-rich, dual-membrane cell envelope that contributes to their impermeability, drug resistance, and unique pathogenic mechanisms. Some lipids play key roles in modulating host immune responses, enabling survival within macrophages, and promoting granuloma formation. Since it is known that lipid remodeling of the cell envelope is correlated with the antibiotics tolerance in mycobacteria we used liquid chromatography coupled to mass spectrometry to analyze the lipid profiles of M. tuberculosis clinical isolates with diverse drug-resistance characteristics in order to investigate if there is any link between Mtb lipids composition, its drugs susceptibility and the antimycobacterial activity of natural small molecules used in combination with first line antibiotics. The results showed that among cross combinations of antibiotics and natural products (piperine and thymoquinone) the potentiation of antimycobacterial activity was obtained in all strains only for rifampicin. Drug-resistant isolates presented the shift in glycerophospholipids building the inner membrane towards molecules with shorter acyl chains, but the decreased membrane hydrophobic thickness was compensated in some strains by increased membrane rigidity. The pXDR/XDR isolates accumulated mycobactins loaded iron and showed dysregulation in the production of phthiocerol/phthiodiolone dimycocerosates and triacylglycerols.

The zebrafish (Danio rerio) has become a widely adopted vertebrate model in biomedical research, offering high translational value while supporting the principles of Replacement, Reduction, and Refinement (3Rs). Here, the Polish Zebrafish Society presents comprehensive, field-specific recommendations for the responsible and effective use of zebrafish across major areas of biomedical research. The document summarizes the scientific rationale and experimental advantages of zebrafish-based approaches in oncology, toxicology, neurology and neuropsychiatry, metabolic diseases, immunology, cardiology, and genetic disease modelling. The model’s key strengths include rapid development, optical transparency, genetic tractability, and strong conservation of molecular and physiological pathways relevant to human disease. These features enable real-time in vivo analysis of pathological processes, high-throughput pharmacological and toxicological screening, and functional validation of disease-associated genes. By integrating ethical considerations with robust experimental evidence, these recommendations aim to promote standardized implementation of zebrafish models in academic research, pharmaceutical development, and regulatory science. Broad adoption of zebrafish-based approaches can accelerate preclinical discovery, enhance translational relevance, and substantially reduce reliance on higher vertebrate models.

Spinal cord injury (SCI) causes significant sensory and motor deficits and paralysis due to the limited regenerative capacity of the mammalian central nervous system (CNS). The inflammatory response triggered by the injury is critical for successful spinal cord regeneration. Galanin is a neuropeptide acting primarily as an inhibitory neuromodulator or neurotransmitter in the central and peripheral nervous systems. Galanin is also expressed in various non-neuronal cell types, including immune cells. Galanin has been implicated in neuroprotection and inflammation; however, its contribution to spinal cord regeneration is not well defined. Here, we investigated the function of galanin in SCI repair in zebrafish (Danio rerio), which possess the remarkable ability to regenerate the CNS. We performed spinal cord transection on 3 days post fertilization (dpf) zebrafish larvae and found that the galanin knockout mutant zebrafish showed delayed axonal regeneration and functional recovery, reduced inflammation-related gene expression during the early inflammatory phase, and impaired migration of neutrophils to the lesion site. These results suggest that galanin plays an important role in the regenerative process of the spinal cord by regulating the inflammatory response caused by SCI.

For thousands of years, medicinal plants and their constituents have been used, mostly empirically/ethnopharmacologically, to cure patients with central nervous system (CNS) disorders. Anxiolytics derived from natural products (NPs) often share similar mechanisms of action to synthetic ones (e.g., benzodiazepines, BDZs). Although typically as effective as synthetic anxiolytics, NPs are considered to be devoid of the serious side effects linked to the use of BDZs. 8-Methoxypeucedanin (8-MP) is a rare furanocoumarin present in the fruits of Peucedanum luxurians Tamamsch. (Apiaceae). The primary objective of the presented study was to assess the anxiolytic activity of 8-MP using a zebrafish (Danio rerio) model of anxiety. Danio rerio larvae at 5 days post-fertilization (dpf) were used, with reversed thigmotaxis considered as an index of the anxiolytic activity. In addition to the behavioral study, qPCR analyses were performed to assess the role of 8-MP in modulating the expression of c-fos and bdnf, two key genes involved in neural activity. As evidenced by the behavioral study, 8-MP (1.5–15 µM) exhibited a significant influence on anxiety, with a U-shape dose–response effect. Moreover, the expression of c-fos and bdnf genes was significantly downregulated, providing novel insights into the mechanisms of action of the tested furanocoumarin.

This study investigated the multilevel effects of environmentally relevant concentrations of fluoxetine on serotonergic signaling and enteric neurogenesis in early zebrafish larvae (Danio rerio). To this end, zebrafish were exposed to various concentrations of fluoxetine for four days, from the 1,000-cell stage to 4 days post-fertilization (dpf).Following exposure, whole larvae were subjected to molecular, morphological, and behavioral analyses. All tested concentrations led to upregulation of the serotonin transporter (slc6a4a). At intermediate concentrations, overexpression of the serotonin receptor htr1aa was observed. The highest concentration caused a reduced total enteric neurons density, while the intermediate concentration reduced the density of serotonergic enteric neurons. Additionally, the highest concentration decreased larval locomotion and impaired their ability to differentiate between light and dark phases.Across all tested concentrations, fluoxetine disrupted serotonergic signaling, impaired enteric neurogenesis, and induced sedative-like behavioral effects.

Introduction: Myo-inositol (MI) is the most abundant inositol found in nature. To date MI supplementation is reported to be effective in the treatment of polycystic ovary syndrome, it is also suggested to alleviate the symptoms of diabetes and neurodegenerative disorders, but to date no statistically significant effects of inositol on depressive and anxiety symptoms were proven. In the study of anxiolytic effects in zebrafish, we often use the thigmotaxis index measuring the ratio of the amount of time the animal spends near the walls compared to the entire arena. Aim: The objective of this paper was to examine the effect of MI on zebrafish embryos’ locomotor activity, as well as its potential anxiolytic activity in zebrafish larvae. Material and methods: In the first part of the experiment, the embryos were incubated with 5, 10, 20, and 40 mg/mL MI. 1-day post fertilization, embryo mobility was evaluated and burst activity was calculated. In the next part of the study, the behavior of 5-day-old larvae was tested. Results: Tests on embryo movement showed an increase in burst activity in the MI group at concentrations of 40 mg/mL (p < 0.0001) and a slight decrease in the group at concentrations of 10 mg/mL (p < 0.05). MI in the light/dark challenge had no impact on the thigmotaxis index. Conclusions: MI was shown to not affect stress reduction in zebrafish larvae. Further research on the potential of MI and other stereoisomers is needed.

Anxiety is one of the most common central nervous system disorders, affecting at least one-quarter of the worldwide population. The medications routinely used for the treatment of anxiety (mainly benzodiazepines) are a cause of addiction and are characterized by many undesirable side effects. Thus, there is an important and urgent need for screening and finding novel drug candidates that can be used in the prevention or treatment of anxiety. Simple coumarins usually do not show side effects, or these effects are much lower than in the case of synthetic drugs acting on the central nervous system (CNS). This study aimed to evaluate the anxiolytic activity of three simple coumarins from Peucedanum luxurians Tamamsch, namely officinalin, stenocarpin isobutyrate, and officinalin isobutyrate, in a 5 dpf larval zebrafish model. Moreover, the influence of the tested coumarins on the expression of genes involved in the neural activity (c-fos, bdnf) or dopaminergic (th1), serotoninergic (htr1Aa, htr1b, htr2b), GABA-ergic (gabarapa, gabarapb), enkephalinergic (penka, penkb), and galaninergic (galn) neurotransmission was assessed by quantitative PCR. All tested coumarins showed significant anxiolytic activity, with officinalin as the most potent compound. The presence of a free hydroxyl group at position C-7 and the lack of methoxy moiety at position C-8 might be key structural features responsible for the observed effects. In addition, officinalin and its isobutyrate upregulated the expression of genes involved in neurotransmission and decreased the expression of genes connected with neural activity. Therefore, the coumarins from P. luxurians might be considered as promising drug candidates for the therapy of anxiety and related disorders.

Epilepsy is a neurological disease that burdens over 50 million people worldwide. Despite the considerable number of available antiseizure medications, it is estimated that around 30% of patients still do not respond to available treatment. Herbal medicines represent a promising source of new antiseizure drugs. This study aimed to identify new drug lead candidates with antiseizure activity from endemic plants of New Caledonia. The crude methanolic leaf extract of Halfordia kendack Guillaumin (Rutaceae) significantly decreased (75 μg/mL and 100 μg/mL) seizure-like behaviour compared to sodium valproate in a zebrafish pentylenetetrazole (PTZ)-induced acute seizure model. The main coumarin compound, halfordin, was subsequently isolated by liquid-liquid chromatography and subjected to locomotor, local field potential (LFP), and gene expression assays. Halfordin (20 μM) significantly decreased convulsive-like behaviour in the locomotor and LFP analysis (by 41.4% and 60%, respectively) and significantly modulated galn, and penka gene expression.

Epilepsy, with about 70 million affected people worldwide, is one of the biggest challenges of medicine today. It is estimated that about one-third of epileptic patients receive inadequate treatment. Inositols have proved effective in many disorders; hence, in the current study, we tested potential antiepileptic properties of scyllo-inositol (SCI)-one of the most common commercially available inositols-in zebrafish larvae with pentylenetetrazol-induced seizures. First, we studied the general effect of SCI on zebrafish motility, and then we tested SCI antiepileptic properties over short (1 h) and long (120 h) exposure protocols. Our results demonstrated that SCI alone does not reduce zebrafish motility regardless of the dose. We also observed that short-term exposure to SCI groups reduced PTZ-treated larva motility compared to controls (p < 0.05). In contrast, prolonged exposure did not produce similar results, likely due to the insufficient concentration of SCI given. Our results highlight the potential of SCI use in epilepsy treatment and warrant further clinical studies with inositols as potential seizure-reducing drugs.

The aim of this study was to examine the effect of microRNA 92b-3p (MiR92b-3p) overexpression on the embryonic development of zebrafish. A synthetic MiR92b-3p analogue (mirVana™ mimic, in vivo-ready) was injected at doses up to 5 ng/embryo into the yolk sac of embryos (2–16 cell stage). At 24 h post fertilization (hpf), the locomotor activity of the embryos was measured, and after hatching (72 hpf), the rates of malformation occurrence, hatching, and mortality were determined. Next, the larvae were fixed for histological and molecular examinations. Exposure to the MiR92b-3p mimic impaired embryonic development, leading to increased occurrence of malformations (i.e., pericardial edema, spine curvature, smaller eyes), decreased locomotor activity and hatching rate, and increased mortality. Importantly, the mimic affected retinal differentiation and lens formation during zebrafish embryogenesis, which suggests that MiR92b-3p could be an important factor in the regulation of fish embryogenesis and ocular development. The expression level of MiR92b-3p was substantially higher in the exposed larvae than in the untreated larvae, indicating that the mimic was successfully delivered to the zebrafish. Although screening of potential MiR92b-3p target genes suggested some changes in their expression levels, these results were inconclusive. Together, this study indicates that MiR92b-3p mimic impairs zebrafish embryonic development, and further research is necessary to identify the MiR92b-3p–regulated cell pathways involved in the impairment of the fish’s development.

Microinjection is a micromanipulation technique that has been used in various fields and in a variety of species, including teleost fish, for over a hundred years. Microinjection is mainly used in genetic, molecular, and toxicological research. The paper describes an experimental study of a microinjection technique for the administration of Infectious Pancreatic Necrosis Virus (IPNV) in fertilized eggs of brook trout, Salvelinus fontinalis (Mitchill), and a rainbow trout Oncorhynchus mykiss (Walbaum) hybrid, Salvelinus fontinalis ♂ × Oncorhynchus mykiss ♀. The oocytes and embryos of these salmonids have complex structures that require modifying the method commonly used in zebrafish, Danio rerio (Hamilton), research. A modular apparatus and technique for injecting brook trout and rainbow brook trout fish embryos with IPNV are described. The modified microinjection method can be used successfully to administer to salmonid eggs infectious substances that simulate the vertical transmission of pathogens.

The river lamprey (L. fluviatilis) is a representative of the ancestral jawless vertebrate group. We performed a histological analysis of trunk muscle fiber differentiation during embryonal, larval, and adult musculature development in this previously unstudied species. Investigation using light, transmission electron (TEM), and confocal microscopy revealed that embryonal and larval musculature differs from adult muscle mass. Here, we present the morphological analysis of L. fluviatilis myogenesis, from unsegmented mesoderm through somite formation, and their differentiation into multinucleated muscle lamellae. Our analysis also revealed the presence of myogenic factors LfPax3/7 and Myf5 in the dermomyotome. In the next stages of development, two types of muscle lamellae can be distinguished: central surrounded by parietal. This pattern is maintained until adulthood, when parietal muscle fibers surround the central muscles on both sides. The two types show different morphological characteristics. Although lampreys are phylogenetically distant from jawed vertebrates, somite morphology, especially dermomyotome function, shows similarity. Here we demonstrate that somitogenesis is a conservative process among all vertebrates. We conclude that river lamprey myogenesis shares features with both ancestral and higher vertebrates.

Microcephaly presents in neurodevelopmental disorders with multiple aetiologies, including bi-allelic mutation in TUBGCP2, a component of the biologically fundamental and conserved microtubule-nucleation complex, γ-TuRC. Elucidating underlying principles driving microcephaly requires clear phenotype recapitulation and assay reproducibility, areas where go-to experimental models fall short. We present an alternative simple vertebrate/invertebrate dual system to investigate fundamental TUBGCP2-related processes driving human microcephaly and associated developmental traits. We show that antisense morpholino knockdown (KD) of the Danio rerio homolog, tubgcp2, recapitulates human TUBGCP2-associated microcephaly. Co-injection of wild type mRNA pre-empts microcephaly in 55% of KD zebrafish larvae, confirming causality. Body shortening observed in morphants is also rescued. Mitotic marker (pH3) staining further reveals aberrantly accumulated dividing brain cells in microcephalic tubgcp2 KD morphants, indicating that tubgcp2 depletion disrupts normal mitosis and/or proliferation in zebrafish neural progenitor brain cells. Drosophila melanogaster double knockouts (KO) for TUBGCP2 homologs Grip84/cg7716 also develop microcephalic brains with general microsomia. Exacerbated Grip84/cg7716-linked developmental aberration versus single mutations strongly suggests interactive or coinciding gene functions. We infer that tubgcp2 and Grip84/cg7716 affect brain size similarly to TUBGCP2 and recapitulate both microcephaly and microcephaly-associated developmental impact, validating the zebrafish/fly research model for human microcephaly. Given the conserved cross-phyla homolog function, the data also strongly support mitotic and/or proliferative disruption linked to aberrant microtubule nucleation in progenitor brain cells as key mechanistic defects for human microcephaly.

Protamine sulfate (PS) is the only available option to reverse the anticoagulant activity of unfractionated heparin (UFH), however it can cause cardiovascular and respiratory complications. We explored the toxicity of PS and its complexes with UFH in zebrafish, rats, and mice. The involvement of nitric oxide (NO) in the above effects was investigated. Concentration–dependent lethality, morphological defects, and decrease in heart rate (HR) were observed in zebrafish larvae. PS affected HR, blood pressure, respiratory rate, peak exhaled CO2, and blood oxygen saturation in rats. We observed hypotension, increase of HR, perfusion of paw vessels, and enhanced respiratory disturbances with increases doses of PS. We found no effects of PS on human hERG channels or signs of heart damage in mice. The hypotension in rats and bradycardia in zebrafish were partially attenuated by the inhibitor of endothelial NO synthase. The disturbances in cardiovascular and respiratory parameters were reduced or delayed when PS was administered together with UFH. The cardiorespiratory toxicity of PS seems to be charge–dependent and involves enhanced release of NO. PS administered at appropriate doses and ratios with UFH should not cause permanent damage of heart tissue, although careful monitoring of cardiorespiratory parameters is necessary.

During a pathological condition, many different systems are involved in the response of an affected organism. Galanin is considered to be a neuropeptide that plays an important role in the central nervous system; however, it is involved in many other biological processes, including the immune response. During our studies, we showed that galanin became upregulated in zebrafish larvae when exposed to copper sulfate. Moreover, the presence of normal levels of galanin, administration of a galanin analog NAX 5055 or galanin overexpression led to lowered lateral line damage and enhanced expression of inflammatory markers compared to the knockout larvae. The results showed that the neuroendocrine system acts multifunctionally and should be considered as a part of the complex neuro–immune–endocrine axis.

Autonomic neurons innervating uterine horn is probably the only nerve cell population capable of periodical physiological degeneration and regeneration. One of the main sources of innervation of the uterus is paracervical ganglion (PCG). PCG is a unique structure of the autonomic nervous system. It contains components of both the sympathetic and parasympathetic nervous system. The present study examines the response of neurons of PCG innervating uterine horn to axotomy caused by partial hysterectomy in the domestic pig animal model. The study was performed using a neuronal retrograde tracing and double immunofluorescent staining for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DβH), choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), neuronal nictric oxide synthase (nNOS), galanin, neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP), somatostatin and substance P (SP). Our study showed that virtually all neurons of the porcine PCG innervating uterine horn are adrenergic and we did not confirm that PCG is the source of cholinergic fibers innervating uterine horn of the pig. After axotomy there was a decrease in expression of catecholamine-synthesizing enzymes (TH, DβH) and a strong increase in the galanin expression. The increase of the number of NPY-IR neurons in the ganglia after axotomy was observed. There were no changes in the expression of other studied substances in the PCG neurons innervating the uterine horn, what was often found in rodents studies. This indicates that neurons can respond to damage in a species-specific way.

In mammals, the relationship between the immune system and behavior is widely studied. In fish, however, the knowledge concerning the brain immune response and behavioral changes during brain viral infection is very limited. To further investigate this subject, we used the model of tilapia lake virus (TiLV) infection of zebrafish (Danio rerio), which was previously developed in our laboratory. We demonstrated that TiLV persists in the brain of adult zebrafish for at least 90 days, even when the virus is not detectable in other peripheral organs. The virions were found in the whole brain. During TiLV infection, zebrafish displayed a clear sickness behavior: decreased locomotor activity, reduced food intake, and primarily localizes near the bottom zone of aquaria. Moreover, during swimming, individual fish exhibited also unusual spiral movement patterns. Gene expression study revealed that TiLV induces in the brain of adult fish strong antiviral and inflammatory response and upregulates expression of genes encoding microglia/macrophage markers. Finally, using zebrafish larvae, we showed that TiLV infection induces histopathological abnormalities in the brain and causes activation of the microglia which is manifested by changes in cell shape from a resting ramified state in mock-infected to a highly ameboid active state in TiLV-infected larvae. This is the first study presenting a comprehensive analysis of the brain immune response associated with microglia activation and subsequent sickness behavior during systemic viral infection in zebrafish.

Isothiocyanates (ITCs) show strong activity against numerous human tumors. Five structurally diverse ITCs were tested in vivo using the zebrafish embryos 6 and 48 h post-fertilization (hpf). The survival rate, hatching time, and gross morphological changes were assessed 24, 48, and 72 h after treatment with all compounds in various doses (1–10 µM). As a result, we selected a phosphonate analog of sulforaphane (P-ITC; 1–3 µM) as a non-toxic treatment for zebrafish embryos, both 6 and 48 hpf. Furthermore, the in vivo anti-cancerogenic studies with selected 3 µM P-ITC were performed using a set of cell lines derived from the brain (U87), cervical (HeLa), and breast (MDA-MB-231) tumors. For the experiment, cells were labeled using red fluorescence dye Dil (1,1′-Dioctadecyl-3,3,3′,3′-Tetramethylindocarbocyanine, 10 μg/mL) and injected into the hindbrain ventricle, yolk sac region and Cuvier duct of zebrafish embryos. The tumor size measurement after 48 h of treatment demonstrated the significant inhibition of cancer cell growth in all tested cases by P-ITC compared to the non-treated controls. Our studies provided evidence for P-ITC anti-cancerogenic properties with versatile activity against different cancer types. Additionally, P-ITC demonstrated the safety of use in the living organism at various stages of embryogenesis.