Ultra-sensitive UHPLC-MS/MS method for simultaneous quantification of 31 neurochemicals in zebrafish larvae and brain.

Effect of the perfluorooctane sulfonamide on glucose and lipid metabolism in 3T3-L1 adipocytes and zebrafish larvae.

Filtered aquatic small tubular mesh-bottomed containers (FAST-MC): A low-cost, efficient method for rearing zebrafish larvae in filtered water.

Neurodevelopmental and behavioural effects of arsenic in zebrafish (Danio rerio).

6PPD exposure reduced the melanin deposition by inhibiting tyrosinase activity in larval zebrafish.

Born in complexity: How the early life environment shapes zebrafish larvae phenotype.

A large Stokes shift peptide-based fluorescent probe for Cd2+ and Hg2+ detection in aqueous solution and its applications in bioimaging, real sample, logic gate and smartphone device.

Adverse adult-onset and multigenerational effects in zebrafish (Danio rerio) developmentally exposed to polystyrene nanoplastics.

Zebrafish ( Danio rerio ) are commonly used to test the impact of pharmacological and toxicological compounds. Larval zebrafish are extensively used because of high throughput procedures allowing simultaneous behavioural measurement in 24-, 48-, or 96-well plates. Often solvents are used as a vehicle for poorly soluble or insoluble compounds, however, the impact of dimethyl sulfoxide (DMSO), methanol, and ethanol after acute administration is not well characterized. Here we investigated the impact of 30-min exposures of DMSO, methanol, and ethanol (0.01%, 0.1%, and 1.0% vol/vol) on 5-day old larval zebrafish locomotion and startle responses. We found no effect of DMSO on distance moved and thigmotaxis in a spontaneous swimming test, and no effect on dark-, light-, or tap-startle responses compared to controls. Methanol and ethanol, both at 1.0% increased the distance moved, and ethanol decreased the dark startle response at 1.0%. Neither ethanol nor methanol had any impact on time in thigmotaxis zone, light- or tap-startle responses. Results from this study suggest that with acute exposure to experimental compounds requiring a solvent, the least impact on behaviour would occur with DMSO, followed by methanol, then ethanol.

The increasing complexity of life science research requires laboratory tools that combine precision, automation, and accessibility. Conventional liquid handling and imaging systems are either separated or integrated at high cost, limiting their adoption in small-scale laboratories. Here we show that G-Bot, a compact five-axis platform, integrates automated liquid handling, live-cell imaging, and real-time data processing into a single system. G-Bot performs complex workflows, e.g., including cell seeding, drug dosing, media exchange, and long-term live-cell imaging, while maintaining stable culture conditions through integrated incubator and stage-top regulation modules. Its imaging capabilities span cells, organoids, and small organisms such as zebrafish larvae, providing high-content, physiologically relevant data. Unlike pipette-based systems, G-Bot employs a tubing-based dispensing mechanism for precise reagent delivery with minimal waste. By unifying liquid handling, imaging, and analysis, G-Bot streamlines laboratory-scale workflows, improves reproducibility, and bridges the gap between manual methods and costly industrial automation, offering broad utility in research and drug discovery.

Investigating the neurodevelopmental toxicity of graphene oxides using 3D human brain organoids and zebrafish models: emphasis on GABAergic neuron alterations at single-cell resolution.

Concurrent endoplasmic reticulum stress and demyelination in DEHP-exposed zebrafish larvae at the early developmental stages.

Most fish are inherently unstable and must swim to stabilize posture. How diurnal fish reduce activity at night while maintaining postural control remains unclear. We defined distinct locomotor strategies that larval zebrafish (Danio rerio) use to control posture and navigate the water column in response to light and circadian cues. In the dark, larvae maintain balance by swimming in long bouts with large nose-up rotations, compensating for nose-down drift accrued during prolonged inactivity. Effective postural compensation requires vestibular sensation from the utricle. By contrast, in the light, larvae navigate with short, frequent, and variable bouts. While lighting exerts a dominant, masking effect on the locomotor strategies, circadian rhythms modulate the extent of each strategy. Our results reveal distinct day-night locomotor strategies and disentangle how ambient light and the internal clock jointly shape balance control and navigation. This work lays the foundation for understanding how external and internal cues interact to govern locomotor activity in freely moving diurnal animals.

Microexon splicing is a vertebrate-conserved process through which small, often in-frame, exons are differentially included during brain development and across neuron types. Although the protein sequences encoded by these exons are highly conserved and can mediate interactions, the neurobiological functions of only a small number have been characterized. To establish a more generalized understanding of their roles in brain development, we used CRISPR/Cas9 to remove 45 microexons in zebrafish and assessed larval brain activity, morphology, and behavior. Most mutants had minimal or no phenotypes at this developmental stage. Among previously studied microexons, we uncovered baseline and stimulus-driven phenotypes for two microexons (meA and meB) in ptprd and reduced activity in the telencephalon in the tenm3 B0 isoform. Although mild neural phenotypes were discovered for several microexons that have not been previously characterized, including in ppp6r3, sptan1, dop1a, rapgef2, dctn4, vti1a, and meaf6. This study establishes a general approach for investigating conserved alternative splicing events and prioritizes microexons for downstream analysis.

Wastewater treatment plants (WWTPs) are recognized as major sources of organic micropollutants (OMPs) for aquatic environments. Yet, chemical monitoring alone may underestimate the ecological risks posed by complex OMP mixtures. Here, we combined an effect-based monitoring (EBM) approach with targeted chemical analysis to assess environmental risks of OMP mixtures in effluents from 16 WWTPs in Flanders, Belgium. Effluent sites were selected from a five-year regional monitoring dataset, prioritizing locations with high cumulative risk quotients. Bioassays using Microcystis aeruginosa (cyanobacteria growth inhibition) and Danio rerio (zebrafish larvae, light/dark locomotive assay) were conducted on effluent extracts. High-resolution mass spectrometry identified 130 compounds, with 26 OMPs quantified across classes, including pharmaceuticals, antibiotics, herbicides, and per- and polyfluoroalkyl substances. Median effective concentrations (EC50) and 10% effective concentrations (EC10) for cyanobacteria inhibition ranged between relative enrichment factors (REF) of 4.1-38 and 1.1-4.7, respectively. Iceberg modeling identified azithromycin and clarithromycin as the main drivers of cyanobacterial inhibition. Zebrafish behavioral responses were significantly affected in 8 of 16 samples (REF 1.25-20), but these differences could not be explained by the available chemical data. Only some suspect compounds were identified, including antidepressants and pesticides, and therefore this remains an interesting aspect for future investigations. Risk characterization for receiving surface waters using chemical-based risk quotients, margin of safety, and effect-based trigger values revealed ecological risk (RQ > 1) in 13 of 16 sites. This study highlights the added value of integrating EBM with chemical monitoring to explain mixture effects, identify key toxicants, and support improved regulatory frameworks for environmental management.

A critical function of the nervous system is to rapidly process sensory information and initiate appropriate behavioral responses. Defects in sensory processing and behavior selection are commonly observed in neuro-psychiatric conditions including anxiety, autism (ASD), and schizophrenia. The etiology of sensory processing disorders remains equivocal; however, it is hypothesized that extrinsic environmental factors can play fundamental roles. In this study we examine the importance of vitamin D (1α, 25-dihydroxyvitamin D3) receptor signaling during early life stage development on sensory processing and neurobehavioral health outcomes. While vitamin D has traditionally been associated with mineral ion homeostasis, accumulating evidence suggests non-calcemic roles for vitamin D including early neurodevelopment. Here we demonstrate that systemic disruption of vitamin D receptor (VDR) signaling with a conditional dominant negative (dnVDR) transgenic zebrafish line results in specific visual and acoustic sensorimotor behavior defects. Induction of dnVDR between 24–72 hours post fertilization (hpf) resulted in modulation of visual motor response with demonstrated attenuation in acute activity and hypolocomotion across multiple swimming metrics when assayed at 6- and 28-days post fertilization (dpf). Disruption in VDR signaling additionally resulted in a strong and specific attenuation of the Long-Latency C-bends (LLC) within the acoustic startle response at 6 dpf while Short-Latency C-bends (SLC) were moderately impacted. Pre-pulse inhibition (PPI) was not impacted in young larvae, however young adult fish exhibited a significantly attenuated PPI at 28 dpf suggesting an inability to properly modulate their startle responses and persistent effects of VDR modulation during early development. Overall, our data demonstrate that modulation of vitamin D signaling during critical windows of development irreversibly disrupts the development of neuronal circuitry associated with sensory processing behaviors which may have significant implications to neurobehavioral health outcomes.

Concurrent consumption of ethanol (EtOH) and herbal preparations containing Withania somnifera (WS, ashwagandha) is increasingly common, but the neurobehavioral and molecular consequences of such interactions remain poorly characterized. This study investigated how three purified withanolides—withanolide A (WITA), withanone (WIN), and withaferin A (WTFA)—modulate the effects of acute EtOH exposure in zebrafish (Danio rerio) larvae. Locomotor behavior was quantified under EtOH concentrations ranging from 0 to 4.0%, and the expression of four GABAA receptor subunit genes (gabra1, gabra2, gabrd, gabrg2) was analyzed by qPCR. EtOH alone induced a biphasic locomotor response, with stimulation at low-to-moderate doses and suppression at higher doses. WITA and WIN modulated this pattern in a dose-dependent manner, preserving or enhancing hyperactivity, while WTFA consistently potentiated locomotor suppression. mRNA profile analysis revealed subunit-specific changes, including downregulation of gabra1 and gabra2, compound-dependent regulation of gabrd, and complex gabrg2 responses. These results demonstrate that individual withanolides distinctly shape behavioral and molecular outcomes of EtOH exposure, suggesting specific interactions at the level of inhibitory neurotransmission. The findings provide mechanistic insight into the combined effects of WS-derived compounds and EtOH and highlight the importance of considering such interactions in both experimental and applied contexts.

Sensory information is fundamental for navigation. Visual motion is used by animals to estimate their traveling distance and direction, and landmarks allow animals to tether their location and orientation to their environment. How such signals are integrated in the vertebrate brain is poorly understood. Here we investigate the representation of directional whole field visual motion and landmark position in the larval zebrafish head direction circuit. Using calcium imaging we show that these stimuli are represented in the habenula, interpeduncular nucleus and anterior hindbrain. In the dorsal interpeduncular nucleus, both stimuli are topographically arranged and align with the representation of the heading signal. Neuronal ablations show that the landmark responses, but not the whole field motion responses, require intact habenula input. Our findings suggest the interpeduncular nucleus as a site for integration of the heading signal with visual information, shedding light on how navigational signals are processed in the vertebrate brain.

Obesity is a global health concern linked to metabolic disorders and gut microbiota dysbiosis, particularly under high-fat diet (HFD) conditions. This study explores the role of imidazole propionate (ImP), a histidine-derived microbial metabolite, in regulating lipid metabolism and the development of obesity. Male C57BL/6 mice were fed either a chow diet or HFD for 15 weeks, followed by plasma metabolomic analysis, which revealed significant downregulation of ImP in obese mice. Functional assays were performed using zebrafish larvae and human adipocytes, with lipid accumulation assessed via Nile Red and Oil Red O staining. Transcriptomic sequencing and KEGG pathway analysis were used to investigate the underlying molecular mechanisms. ImP treatment notably reduced lipid accumulation in both zebrafish larvae and human adipocytes. RNA-seq and protein expression analyses revealed that ImP suppressed peroxisome proliferator-activated receptor (PPAR) pathway key components, such as FABP4, ACSL4, and CEBPα. These findings demonstrate that ImP attenuates lipid accumulation by inhibiting the PPAR signaling pathway. As a gut microbial metabolite, ImP may offer therapeutic potential in preventing or treating HFD-induced obesity.

Assessment of the sub-lethal effects induced by three tire rubber-derived contaminants on zebrafish larvae.