In order to develop a transgenic zebrafish line with green fluorescent protein (enhanced green fluorescent protein, EGFP) expressed specifically in muscle and heart, the recombinant expression vector constructed using the zebrafish ttn.2 gene promoter fragment and EGFP gene coding sequence and the capped mRNA of Tol2 transposase were co-injected into the zebrafish 1-cell stage embryos. The stable genetic Tg (ttn.2: EGFP) transgenic zebrafish line was successfully developed by fluorescence detection, followed by genetic hybridization screening and molecular identification. Fluorescence signals and whole-mount in situ hybridization showed that EGFP expression was located in muscle and heart, the specificity of which was consistent with the expression of ttn.2 mRNA. Inverse PCR showed that EGFP was integrated into chromosomes 4 and 11 of zebrafish in No. 33 transgenic line, while integrated into chromosome 1 in No. 34 transgenic line. The successful construction of this fluorescent transgenic zebrafish line, Tg (ttn.2: EGFP), laid a foundation for the research of muscle and heart development and related diseases. In addition, the transgenic zebrafish lines with strong green fluorescence can also be used as a new ornamental fish.
Animals ; Zebrafish/genetics* ; Animals, Genetically Modified/genetics* ; Green Fluorescent Proteins/metabolism* ; Zebrafish Proteins/genetics* ; Promoter Regions, Genetic

Schizothorax argentatus that only distributes in the Ili River basin in Xinjiang is one of the rare and endangered species of schizothorax in China, thus has high scientific and economic values. In this study, the complete mitochondrial genome sequence of S. argenteus with a length of 16 580 bp was obtained by high-throughput sequencing. The gene compositions and arrangement were similar to those of typical vertebrates. It contained 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding region (D-loop). The nucleotide compositions were A (30.25%), G (17.28%), C (27.20%), and T (25.27%), respectively, showing obvious AT bias and anti-G bias. Among the tRNA genes, only tRNA-Ser^(GCU) could not form a typical cloverleaf structure due to the lack of dihydrouracil arm. The AT-skew and GC-skew values of the ND6 gene were fluctuating the most, suggesting that the gene may experience different selection and mutation pressures from other genes. The mitochondrial control region of S. argenteus contained three different domains, i.e., termination sequence region (ETAS), central conserved region (CSB-F, CSB-E, CSB-D, and CSB-B), and conserved sequence region (CSB1, CSB2, and CSB3). The conserved sequence fragment TT (AT) nGTG, which was ubiquitous in Cypriniformes, was identified at about 50 bp downstream CSB3. Phylogenetic relationships based on the complete mitochondrial genome sequence of 28 Schizothorax species showed that S. argenteus had differentiated earlier and had a distant relationship with other species, which may be closely related to the geographical location and the hydrological environment where it lives.
Animals ; Genome, Mitochondrial/genetics* ; Phylogeny ; Sequence Analysis, DNA ; Cyprinidae/genetics* ; RNA, Transfer/genetics* ; DNA, Mitochondrial/genetics* ; Genes, Mitochondrial

The immunomodulatory effect of Saposhnikoviae Radix polysaccharide(SRP) was evaluated based on the zebrafish mo-del, and its mechanism was explored by transcriptome sequencing and real-time fluorescence-based quantitative PCR(RT-qPCR). The immune-compromised model was induced by navelbine in the immunofluorescence-labeled transgenic zebrafish Tg(lyz: DsRed), and the effect of SRP on the density and distribution of macrophages in zebrafish was evaluated. The effect of SRP on the numbers of macrophages and neutrophils in wild-type AB zebrafish was detected by neutral red and Sudan black B staining. The content of NO in zebrafish was detected by DAF-FM DA fluorescence probe. The content of IL-1β and IL-6 in zebrafish was detected by ELISA. The differentially expressed genes(DEGs) of zebrafish in the blank control group, the model group, and the SRP treatment group were analyzed by transcriptome sequencing. The immune regulation mechanism was analyzed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment, and the expression levels of key genes were verified by RT-qPCR. The results showed that SRP could significantly increase the density of immune cells in zebrafish, increase the number of macrophages and neutrophils, and reduce the content of NO, IL-1β, and IL-6 in immune-compromised zebrafish. The results of transcriptome sequencing analysis showed that SRP could affect the expression level of immune-related genes on Toll-like receptor pathway and herpes simplex infection pathway to affect the release of downstream cytokines and interferon, thereby completing the activation process of T cells and playing a role in regulating the immune activity of the body.
Animals ; Zebrafish/genetics* ; Interleukin-6/genetics* ; Gene Expression Profiling ; Cytokines/genetics* ; Macrophages ; Transcriptome

OBJECTIVE: To evaluate toxicity of raw extract of Panax notoginseng (rPN) and decocted extract of PN (dPN) by a toxicological assay using zebrafish larvae, and explore the mechanism by RNA sequencing assay. METHODS: Zebrafish larvae was used to evaluate acute toxicity of PN in two forms: rPN and dPN. Three doses (0.5, 1.5, and 5.0 µ g/mL) of dPN were used to treat zebrafishes for evaluating the developmental toxicity. Behavior abnormalities, body weight, body length and number of vertebral roots were used as specific phenotypic endpoints. RNA sequencing (RNA-seq) assay was applied to clarify the mechanism of acute toxicity, followed by real time PCR (qPCR) for verification. High performance liquid chromatography analysis was performed to determine the chemoprofile of this herb. RESULTS: The acute toxicity result showed that rPN exerted higher acute toxicity than dPN in inducing death of larval zebrafishes (P<0.01). After daily oral intake for 21 days, dPN at doses of 0.5, 1.5 and 5.0 µ g/mL decreased the body weight, body length, and vertebral number of larval zebrafishes, indicating developmental toxicity of dPN. No other adverse outcome was observed during the experimental period. RNA-seq data revealed 38 genes differentially expressed in dPN-treated zebrafishes, of which carboxypeptidase A1 (cpa1) and opioid growth factor receptor-like 2 (ogfrl2) were identified as functional genes in regulating body development of zebrafishes. qPCR data showed that dPN significantly down-regulated the mRNA expressions of cpa1 and ogfrl2 (both P<0.01), verifying cpa1 and ogfrl2 as target genes for dPN. CONCLUSION This report uncovers the developmental toxicity of dPN, suggesting potential risk of its clinical application in children.
Animals ; Zebrafish/genetics* ; Saponins/pharmacology* ; Panax notoginseng/chemistry* ; Larva ; Sequence Analysis, RNA

Objective: To investigate the toxicity of tris (2-chloropropyl) phosphate (TCIPP) and tributyl phosphate (TnBP) on the growth and development of zebrafish embryos, as well as to explore the underlying mechanisms at the transcriptional level. Methods: With zebrafish as a model, two hpf zebrafish embryos were exposed to TCIPP and TnBP (0.1, 1, 10, 100, 500, and 1 000 μmol/L) using the semi-static method, and their rates of lethality and hatchability were determined. The transcriptome changes of 120 hpf juvenile zebrafish exposed to environmentally relevant concentrations of 0.1 and 1 μmol/L were measured. Results: The 50% lethal concentrations (LC₅₀) of TCIPP and TnBP for zebrafish embryos were 155.30 and 27.62 μmol/L (96 hpf), 156.5 and 26.05 μmol/L (120 hpf), respectively. The 72 hpf hatching rates of TCIPP (100 μmol/L) and TnBP (10 μmol/L) were (23.33±7.72)% and (91.67±2.97)%, which were significantly decreased compared with the control group (P<0.05). Transcriptome analysis showed that TnBP had more differential genes (DEGs) than TCIPP, with a dose-response relationship. These DEGs were enriched in 32 pathways in total, including those involved in oxidative stress, energy metabolism, lipid metabolism, and nuclear receptor-related pathways, using the IPA pathway analysis. Among them, three enriched pathways overlapped between TCIPP and TnBP, including TR/RXR activation and CAR/RXR activation. Additionally, DEGs were also mapped onto pathways of LXR/RXR activation and oxidative stress for TnBP exposure only. Conclusion: Both TCIPP and TnBP have growth and developmental toxicities in zebrafish embryos, with distinct biomolecular mechanisms, and TnBP has a stronger effect than TCIPP.
Animals ; Zebrafish/metabolism* ; Embryo, Nonmammalian/metabolism* ; Transcriptome ; Oxidative Stress ; Water Pollutants, Chemical/metabolism*

Objective: To detect the therapeutic efficacy of FGF21 analogues on the zebrafish model of non-alcoholic fatty liver disease. Methods: A zebrafish model of non-alcoholic fatty liver disease was established by providing the normal diet fed to wild-type zebrafish three times daily. PF-05231023 was administered exogenously at a final concentration of 0.5 μmol/L. Body length, body weight, triglycerides, and other indexes were measured after 20 days. Pathological changes were evaluated in liver tissue sections by HE staining. Quantitative PCR was used to identify expressional changes in genes related to lipid metabolism, endoplasmic reticulum stress, and inflammation. Results: QPCR and immunofluorescence staining results showed that FGF21 was highly expressed in the zebrafish model group. The addition of the FGF21 analogue PF-05231023 significantly reduced the body length and body weight (P < 0.01), and the triglyceride content (P < 0.05) in the zebrafish model group. The liver HE staining results showed that PF-05231023 had alleviated the large and tiny bullae fat, lesions, and others in the zebrafish model group. The quantitative PCR results demonstrated that PF-05231023 reduced the expression of lipogenic factors (P < 0.01), inflammatory-related factors (P < 0.001), and genes related to endoplasmic reticulum stress (P < 0.05), but raised lipid-oxidation-related factors (P < 0.05) in the zebrafish model group. The addition of PF-05231023 reduced oleic acid-induced lipid and triglyceride levels in HepG2 cells. Conclusion: FGF21 analogue addition can improve indexes in the zebrafish disease model of non-alcoholic fatty liver disease.
Animals ; Body Weight ; Diet, High-Fat ; Lipids ; Liver/pathology* ; Non-alcoholic Fatty Liver Disease/pathology* ; Triglycerides/metabolism* ; Zebrafish/metabolism* ; Zebrafish Proteins

OBJECTIVE: To explore the role of the Notch signaling pathway in regulating neuronal differentiation and sensorimotor ability in a zebrafish model of fetal alcohol spectrum disorder. METHODS: Zebrafish embryos treated with DMSO or 50 μmol/L DAPT (a Notch signaling pathway inhibitor) were examined for mortality rate, hatching rate, malformation rate, and body length at 15 days post fertilization (dpf). The mRNA expression levels of sox2, neurogenin1 and huc in the treated zebrafish embryos were detected using in situ hybridization and qRT-PCR, and their behavioral responses to strong light and vibration stimulation were observed. The zebrafish embryos were then exposed to DMSO, 1.5% ethanol, DAPT, or both ethanol and DAPT, and the changes in mRNA expression levels of sox2, neurogenin1, huc, and the Notch signaling pathway genes as well as behavioral responses were evaluated. RESULTS: Exposure to 50 μmol/L DAPT significantly increased the mortality rate of 1 dpf zebrafish embryos (P < 0.01), decreased the hatching rate of 2 dpf embryos (P < 0.01), increased the malformation rate of 3 dpf embryos (P < 0.001), and reduced the body length of 15 dpf embryos (P < 0.05). DAPT treatment significantly downregulated sox2 mRNA expression (P < 0.01) and increased neurogenin1 (P < 0.05) and huc (P < 0.01) mRNA expressions in zebrafish embryos. The zebrafish with DAPT treatment exhibited significantly shortened movement distance (P < 0.001) and lowered movement speed (P < 0.05) in response to all the stimulation conditions. Compared with treatment with 1.5% ethanol alone, which obviously upregulated notch1a, her8a and NICD mRNA expressions in zebrafish embryos (P < 0.05), the combined treatment with ethanol and DAPT significantly increased neurogenin1 and huc mRNA expression, decreased sox2 mRNA expression (P < 0.01), and increased the moving distance and moving speed of zebrafish embryos in response to strong light stimulation (P < 0.05). CONCLUSION Ethanol exposure causes upregulation of the Notch signaling pathway and impairs neuronal differentiation and sensorimotor ability of zebrafish embryos, and these detrimental effects can be lessened by inhibiting the Notch signaling pathway.
Animals ; Zebrafish ; Amyloid Precursor Protein Secretases ; Dimethyl Sulfoxide ; Platelet Aggregation Inhibitors ; Antineoplastic Agents ; Ethanol/adverse effects* ; Signal Transduction

OBJECTIVE: To investigate the anti-angiogenic activity of Kunxian Capsule (KX) extract and explore the underlying molecular mechanism using zebrafish. METHODS: The KX extract was prepared with 5.0 g in 100 mL of 40% methanol followed by ultrasonication and freeze drying. Freeze dried KX extract of 10.00 mg was used as test stock solution. Triptolide and icariin, the key bioactive compounds of KX were analyzed using ultra-high performance liquid chromatography. The transgenic zebrafish Tg(flk1:GFP) embryos were dechorionated at 20-h post fertilization (hpf) and treated with PTK 787, and 3.5, 7, 14 and 21 µg/mL of KX extract, respectively. After 24-h post exposure (hpe), mortality and malformation (%), intersegmental vessels (ISV) formation, and mRNA expression level of angiogenic pathway genes including phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), extracellular signal-regulated kinases (ERKs), mitogen-activated protein kinase (MAPK), vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF-2) were determined. Further, the embryos at 72 hpf were treated with KX extract to observe the development of sub-intestinal vein (SIV) after 24 hpe. RESULTS: The chromatographic analysis of test stock solution of KX extract showed that triptolide and icariin was found as 0.089 mg/g and 48.74 mg/g, respectively, which met the requirements of the national drug standards. In zebrafish larvae experiment, KX extract significantly inhibited the ISV (P<0.01) and SIV formation (P<0.05). Besides, the mRNA expression analysis showed that KX extract could significantly suppress the expressions of PI3K and AKT, thereby inhibiting the mRNA levels of ERKs and MAPK. Moreover, the downstream signaling cascade affected the expression of VEGF and its receptors (VEGFR and VEGFR-2). FGF-2, a strong angiogenic factor, was also down-regulated by KX treatment in zebrafish larvae. CONCLUSION KX extract exhibited anti-angiogenic effects in zebrafish embryos by regulating PI3K/AKT-MAPK-VEGF pathway and showed promising potential for RA treatment.
Animals ; Fibroblast Growth Factor 2 ; Human Umbilical Vein Endothelial Cells ; Mitogen-Activated Protein Kinases/metabolism* ; Phosphatidylinositol 3-Kinase ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Vascular Endothelial Growth Factor A/metabolism* ; Zebrafish

Accurate and efficient methods for identifying and tracking each animal in a group are needed to study complex behaviors and social interactions. Traditional tracking methods (e.g., marking each animal with dye or surgically implanting microchips) can be invasive and may have an impact on the social behavior being measured. To overcome these shortcomings, video-based methods for tracking unmarked animals, such as fruit flies and zebrafish, have been developed. However, tracking individual mice in a group remains a challenging problem because of their flexible body and complicated interaction patterns. In this study, we report the development of a multi-object tracker for mice that uses the Faster region-based convolutional neural network (R-CNN) deep learning algorithm with geometric transformations in combination with multi-camera/multi-image fusion technology. The system successfully tracked every individual in groups of unmarked mice and was applied to investigate chasing behavior. The proposed system constitutes a step forward in the noninvasive tracking of individual mice engaged in social behavior.
Animals ; Mice ; Deep Learning ; Zebrafish ; Algorithms ; Neural Networks, Computer ; Social Behavior

Evading or escaping from predators is one of the most crucial issues for survival across the animal kingdom. The timely detection of predators and the initiation of appropriate fight-or-flight responses are innate capabilities of the nervous system. Here we review recent progress in our understanding of innate visually-triggered defensive behaviors and the underlying neural circuit mechanisms, and a comparison among vinegar flies, zebrafish, and mice is included. This overview covers the anatomical and functional aspects of the neural circuits involved in this process, including visual threat processing and identification, the selection of appropriate behavioral responses, and the initiation of these innate defensive behaviors. The emphasis of this review is on the early stages of this pathway, namely, threat identification from complex visual inputs and how behavioral choices are influenced by differences in visual threats. We also briefly cover how the innate defensive response is processed centrally. Based on these summaries, we discuss coding strategies for visual threats and propose a common prototypical pathway for rapid innate defensive responses.
Mice ; Animals ; Zebrafish ; Neurons/physiology* ; Visual Perception/physiology*