• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.749-752
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• 2020

In the search for novel, natural melanogenesis inhibitors, a new sesquiterpene, inularin, was isolated from the flowers of Inula britannica, and the structure was determined using spectroscopic and chemical methods. The antimelanogenic effects of inularin on B16F10 melanoma cells and zebrafish embryos were evaluated. Inularin dose-dependently reduced melanocyte-stimulating hormone-induced melanin production and L-DOPA oxidation in B16F10 cells. Zebrafish embryos were used to confirm the antimelanogenic activity. Inularin significantly decreased the pigmentation of embryos compared with untreated controls.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.1
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• pp.17-24
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• 2021

In this study, the potential toxicity of isoprocarb was demonstrated using zebrafish embryos. We treated isoprocarb (0, 29, and 58 mg/L) to the zebrafish embryos for 72 h then, we estimated morphological changes and apoptotic cell numbers. The increasing extent of apoptosis from the anterior to posterior region of developing zebrafish larvae was correlated with toxicity in the overall development process, including growth and normal organ formation. The appearance of abnormalities in the isoprocarb-treated groups in comparison to normal developing zebrafish larvae was verified using quantitative image analysis based on ImageJ software program. The vascular system comprising a complex interconnection of blood vessels was visualized in vessel-fluorescent transgenic zebrafish (fli1:eGFP). The main vasculature was malformed on isoprocarb treatment, and this was also related to cardiac defects. Taken together, normal embryonic development in zebrafish was interrupted owing to the acute toxicity of isoprocarb.

• Environmental Analysis Health and Toxicology
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• v.22 no.3
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• pp.189-196
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• 2007

[ $TiO_2$ ] is widely used because it is non-toxic. Recently, however, nanometer size $TiO_2$ particles (P-25) have been produced and used to increase the photo catalysis efficiency. Nanometer-sized $TiO_2$ is efficient, but due to its small size ($20{\sim}30\;nm$), it can flow into ecosystems and into cells. Thus, it may affect human health. Additionally, $TiO_2$ can produce a second contaminant, OH-radical, which is a health risk for all living organisms during photo degradation reaction. Hence, when nanometer-sized $TiO_2$ flows into natural streams and attaches to living organisms, it will create health risks. We investigated the biological toxicity of this condition in zebrafish embryos. We observed abnormal morphology, hatching rate, and measured the catalase activity to determine anti-oxidation at 100 post fertilization hours. Zebrafish were somewhat affected by $TiO_2$ nanometer sized particles under UV-A (a condition similar to sunlight). Powdered $TiO_2$ is toxic to the zebrafish fly. Even without light, $TiO_2$ particles attached to embryos and flies, having an effect on both.

• Development and Reproduction
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• v.26 no.2
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• pp.79-90
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• 2022

Krüppel-like factor 10 (KLF10) regulates various cellular functions, such as proliferation, differentiation and apoptosis, as well as the homeostasis of several types of tissue. In the present study, we attempted a loss-of-function analysis of zebrafish Klf11a and Klf11b, which constitute human KLF10 homologs. Embryos injected with klf11b-morpholino (MO) showed developmental retardation and cell death, whereas klf11a-MO-injected embryos showed normal development. In klf11b-MO-injected embryos, a dramatic increase in the amount of zebrafish p53 mRNA might be the cause of the increase in that of bax. The degree of apoptosis decreased in the klf11b-MO and p53-MO co-injected embryos. These findings imply that KLF10 is a negative regulator of p53-dependent transcription, suggesting that the KLF10/p53 complex may play an important role in apoptosis for maintenance of tissue homeostasis during embryonic development.

• Molecules and Cells
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• v.38 no.11
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• pp.975-981
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• 2015

Precise 3D spatial mapping of cells and their connections within living tissues is required to fully understand developmental processes and neural activities. Zebrafish embryos are relatively small and optically transparent, making them the vertebrate model of choice for live in vivo imaging. However, embryonic brains cannot be imaged in their entirety by confocal or two-photon microscopy due to limitations in optical range and scanning speed. Here, we use light-sheet fluorescence microscopy to overcome these limitations and image the entire head of live transgenic zebrafish embryos. We simultaneously imaged cranial neurons and blood vessels during embryogenesis, generating comprehensive 3D maps that provide insight into the coordinated morphogenesis of the nervous system and vasculature during early development. In addition, blood cells circulating through the entire head, vagal and cardiac vasculature were also visualized at high resolution in a 3D movie. These data provide the foundation for the construction of a complete 4D atlas of zebrafish embryogenesis and neural activity.

• Journal of Life Science
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• v.16 no.4
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• pp.571-578
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• 2006

HtrA2/Omi, a mitochondrial trypsin-like serine protease, is pivotal in regulating apoptotic cell death. Several lines of recent evidence suggest that HtrA2 is associated with the pathogenesis of neurodegenerative disorders; however, the physiological function of HtrA2 still remains elusive. For studying physiological function of HtrA2 in depth, it is necessary to develop a suitable expression system in the model animal. We therefore utilized the zebrafish as a model animal to establish expression of human HtrA2 (hHtrA2) in vivo. For expression of mature HtrA2 as GFP fusion in zebrafish embryos, the HtrA2 (WT) or (S306A) cDNAs with the C-terminal GFP tag were inserted into the pCS2+ plasmid. Expression patterns of HtrA2 in HEK293 cells were first monitored by immunofluorescence staining and immunoblot assays, showing approximately 64 kDa of the HtrA2-GFP fusion proteins. Subsequently, the hHtrA2 plasmid DNA or in vitro transcribed mRNA was microinjected into zebrafish embryos. The expression patterns of HtrA2 in Zebrafish embryos were monitored by GFP fluorescence in 24 hours-post-fertilization (hpf). Although expression patterns of HtrA2-GFP in developing embryos were different between the injected DNA and mRNA, both nucleic acids revealed good expression levels to further study the physiological role of HtrA2 in vivo. This study provides a suitable condition for expressing hHtrA2 in the zebrafish embryos as well as a method for generating useful system to investigate physiological properties of the specific human genes.

• Fisheries and Aquatic Sciences
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• v.20 no.12
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• pp.32.1-32.7
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• 2017

Recent in vitro studies have demonstrated that extract of soft coral Dendronephthya gigantea (SCDE) had strong anti-inflammatory activities. However, the direct effects of SCDE on anti-inflammatory activities in vivo model remained to be determined. Therefore, the present study was designed to assess in vivo anti-inflammatory effect of SCDE using lipopolysaccharide (LPS)-stimulated zebrafish model. We also investigated whether SCDE has toxic effects in zebrafish model. The survival, heart beat rate, and developmental abnormalities were no significant change in the zebrafish embryos exposed to at a concentration below $100{\mu}g/ml$ of SCDE. However, lethal toxicity was caused after exposure to 200 and $400{\mu}g/ml$ of SCDE. Treating zebrafish model with LPS treatment significantly increased the reactive oxygen species (ROS) and nitric oxide (NO) generation. However, SCDE inhibited this LPS-stimulated ROS and NO generation in a dose-dependent manner. These results show that SCDE alleviated inflammation by inhibiting the ROS and NO generation induced by LPS treatment. In addition, SCDE has a protective effect against the cell damage induced by LPS exposure in zebrafish embryos. This outcome could explain the profound anti-inflammatory effect of SCDE both in vitro as well as in vivo, suggesting that the SCDE might be a strong anti-inflammatory agent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.31-41
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• 2018

Seaweeds are composed of a variety of bioactive substances, including polysaccharides, pigments, minerals, peptides, and polyphenols. Among these substances, the arsenic content of seaweeds has been a significant cause for concern. The present study evaluated the toxicity of arsenic from three species of seaweed using a zebrafish Danio rerio model. The arsenic-rich extracts were obtained from Ecklonia cava (ECAE), Undaria pinnatifida (UPAE) and Hizikia fusiformis (HFAE) using a solvent of 50% methanol and 1% $HNO_3$. We investigated the toxicity of the arsenic-rich extracts in zebrafish embryos through survival rate, heart rate, yolk sac edema size, cell death, reactive oxygen species (ROS) production and real-time polymerase chain reaction (PCR). The hepatotoxicity of arsenic-rich extracts was assessed in the liver of adult zebrafish through real-time PCR and histopathology. The survival rates of embryos and adult zebrafish showed no significant changes at any concentration. At 100 ppm, embryos did not exhibit significant differences in heart rate, yolk sac edema size, cell death or ROS production. In addition, apoptosis-related genes in larvae and liver tissue were unaffected by treatment with arsenic-rich extracts. These data will help clarify that developmental changes, hepatic oxidative stress, and apoptosis are not associated with toxicity from arsenic-rich seaweed extracts in a zebrafish model.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.1
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• pp.28-34
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• 2020

Imazosulfuron is globally considered as a relatively safe herbicide that controls plant growth by interfering with amino acid synthesis. It is stable, persists in the soil, and has low toxicity; however, studies about the toxic effects of imazosulfuron on non-targeted aquatic vertebrates are scarce. In this study, imazosulfuron was able to induce acute lethality on zebrafish embryos within 48 h. Imazosulfuron also had adverse effects on heartbeats and induced abnormal development with pericardial edema and scoliosis. Moreover, apoptosis and oxidative stress were increased by imazosulfuron in a dose-dependent manner. Thus, all our results showed that imazosulfuron has toxic effects on zebrafish embryogenesis.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1179-1184
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• 2008

Commercial nanometer sized silver is widely used for its antibacterial effect; however, nanoparticles may also have ecotoxicological effects after being discharged into water. Nanometer sized silver can flow into aquatic environments, where it can exert a variety of physiologically effects in living organisms, including fish. The present study aimed to investigate the effect of nanometer sized silver on the development of zebrafish embryos, analyze the properties of commercial nanometer sized silver and define the toxicity relationship between embryogenesis and hatched flies. The commercial nanometer sized silver was analyzed in the $Ag^+$ ion form. The hatch rate decreased in the nano-silver exposed groups (10 and 20 ppt); furthermore, the hatched flies had an abnormal notochord, weak heart beat, damaged eyes and curved tail. The expression of the Sel N1 gene decreased in the nano-silver exposed groups, and the catalase activities of the exposed groups increased relative to those in the control group. Therefore, the $Ag^+$ ions in commercial nanometer sized silver could accumulate in aquatic environments and seriously damage the development of zebrafish embryos.