Purpose: Diabetes is a metabolic disease that occurs when the pancreas does not produce enough insulin (Type I diabetes) or when the body does not effectively use the insulin (Type II diabetes). One of the most common complication of diabetes is diabetic retinopathy(DR). DR is a time-dependent disease and induces blindness. DR produces reactive oxygen species (ROS) and superoxide is mainly made from mitochondria electron chain and it is harmful to eyes. Methods: In this study, eyes were enucleated from glucose-immersed zebrafish which is good model to generate diabetes and then mitochondria were isolated to evaluate activities of mitochondria electron transfer complex. Activity of mitochondrial electron transfer complex in eyes was measured by UV-vis spectrometer. Results: After the glucose immersion, the amount of mitochondria in eyes was increased compared to non-glucose-immersed zebrafish. Mitochondrial complex I, II, III, and IV activities of glucose-immersed zebrafish was improved compared to non-glucose-immersed zebrafish. Conclusions: These results indicated that 3 days or 7 days glucose immersion on zebrafish to induce the early stage of diabetes on zebrafish. Zebrafish might contribute to metabolic compensatory mechanisms in eyes to restore their mitochondrial homeostasis on the early stage of diabetes.

Oil spills have occurred throughout the years of industrialization and represent a global challenge as they affect vast areas of the ocean. The toxicity of crude oil to aquatic organisms has been extensively investigated, but the potential impacts of crude oil on vertebrate development remain largely unknown. Here, we investigated the effects of dispersants used in treating a recent oil spill, as well as that of crude oil, on vertebrates by using the zebrafish (Danio rerio) model species, which has been widely used in empirical studies of both early embryonic development and adult physiology. Chronic exposure to crude oil resulted in marked developmental abnormalities, including pericardial edema, abnormal trunk vessel development, retardation of axonal branching, and abnormal jaw development. Embryonic development was affected more severely by exposure to the oil-dispersant combination than to the oil alone. Thus, the zebrafish in vivo model system suggests that dispersant treatment can have detrimental developmental effects on vertebrates and its potential impact on marine life, as well as humans, should be carefully considered in clean-up efforts at the site of an oil spill.

JAZF1 (Juxtaposed with Another Zinc Finger gene 1) transcription factor are Zn-finger proteins that bind to the nuclear orphan receptor TAK/TR4 (Nakajima et al., 2004). The nuclear orphan receptor TAK1/TR4 functions as a positive as well as a negative regulator of transcription. It was recently reported that congenital cardiovascular malformations are significantly more frequent in Neurofibromatosis 1 (NF1) patients with microdeletion syndrome than in those with classical NF1. JAZF1 was expressed in adult heart of patients with microdeletion syndrome. JAZF1 is highly conserved among various species include zebrafish. We hypothesized that the expression of zebrafish Jazf1 may lead to severe forms of congenital heart disease that allow the survival of newborns and adults. In this study, we created Jazf1 transgenic zebrafish which over-express zebrafish Jazf1 cDNA under control of the CMV promoter. Our results suggested that Jazf1 expression may play an important role in zebrafish cardiac development.

The acute and subacute toxicities of copper sulfate were evaluated in zebrafish (Brachydanio rerio). Dipping of fishes for acute toxicity was performed for a period of 24 h, and TLm24h value (median tolerance limit = LC50) was 1.36 ppm. Clubbing of gill filaments due to severe epithelial hyperplasia of gill lamella were oberved. And epithelial edema, fusion and necrosis of renal tubules were presented. The most significant change was mild epithelial hyperplasia of gill lamella in subacute toxicity test which fishes were exposed to 0.15 ppm of copper sulfate for 1 week.

본 연구는 zebrafish를 실험어류로 하여 국내에서 혼합제로 사용되고 있는 dichlorvos와 phosalone을 선정하여 단독 및 혼합폭로시 생물농축계수와 배설속도상수를 측정함으로써, 두 농약의 공존이 개별농약의 생물농축성에 미치는 영향을 알아보고자 하였다. Dichlorvos의 phosalone의 혼합폭로시(dichlorvos : 0.55㎍/㎖, phosalone : 0.01㎍/㎖) zebrafish 체내에서 dichlorvos의 농축정도는 6시간에 정류상태에 도달하여 72시간까지 거의 일정하였으며 단독폭로시(12시간0보다 더 빠르게 정류상태에 도달하였다. 6시간에서 72시간 사이의 BCF평균값은 0.080(n=5)으로 단독폭로시의 12시간에서 72시간 사이의 BCF평균값 0.74(n=4)보다 더 높게 측정되었다. 배설속도상수는 0.12h^-1으로 단독폭로시와 차이가 거의 없었다. Dichlorvos와 phosalone의 혼합폭로시(dichlorvos : 0.55㎍/㎖, phosalone : 0.01㎍/㎖) zebrafish 체내에서 phosalone의 농축정도는 단독폭로시와 같이 12시간 정류상태에서 도달하여 72시간까지 거의 일정하였고, 12시간에서 72시간 사이의 BCF평균값은 53.89(n=4)로 단독폭로시의 BCF평균값 48.88(n=4)보다 더 높게 측정되었다. 배설속도상수는 단독폭로시와 같이 6시간 안에 어류체내에서 phosalone이 모두 배출되어 구하지 못했다. 두농약(dichlorvos, phosalone)의 혼합폭로시의 BCF평균값이 단독폭로시의 BCF평균값보다 더 높게 나왔으나 각 실험시간대(6, 12, 24, 48, 72시간)의 BCF실험값을 t-test로 분석한 결과 phosalone의 48시간을 제외하고는 두 농약의 단독폭로와 혼합폭로시의 BCF값에는 유의한 차이가 없었다(p<0.05). 이상의 결과를 종합해 볼 때, dichlorvos와 phosalone을 zebrafish에 혼합폭로시 개개 농약의 생물농축성과 배설속도상수에는 유의한 영향을 미치지 않는 것으로 나타났다.

Programmed cell death (PCD) is thought as a well-controlled process by which unwanted cells are selectively eliminated. During the last decade many researches have elucidated molecules and their interactions involved in cell death by using largely in vitro induction of cell death or survival signals in a more defined manner, While these critical information and novel findings provide us with clearer understanding of mechanisms underlying cell death, it does by no means explain how PCD occurs and which cells or tissues are affected during normal embryonic development in vivo. In this study, we used zebrafish to examine whether the PCD is occurring selectively or randomly in developing embryos by whole mount in situ TUNEL analysis with specific markers for neural cells. The result revealed that the degree and distribution of TUNEL staining varied considerably throughout gastrulation stage, and there was also a number of TUNEL-negative embryos. Most of TUNEL-positive cells were scattered randomly throughout the blastoderm. During the gastrulation stage about 75 % of the embryos analyzed exhibited more than 5 TUNEL-positive cells. As the dorsal epiblast begins to thicken rather abruptly near the end of gastrulation, TUNEL-positive cells were mainly located along the dorsal side. Although there were some variations in TUNEL staining during segmentation and pharyngeal stages, TUNEL staining continued to be localized to the central nervous system, and was also detected in the sensory organs, trigeminal ganglions, and the primary sensory neurons. High levels of the cell death in developing brain between 20-somite and prim-6 stages are thought to play a role in the morphogenesis and organization of the brain. At prim-16 stage, cell death is considerably reduced in the brain region. Dying cells are mainly localized to the prospective brain region where ectodermal cells are about to initiate neurogenesis. As development progressed, high levels and more reproducible patterns of cell death were observed in the developing nervous system. Intensive TUNEL staining was restricted to the trigeminal ganglions, the primary sensory neurons, and sensory organs, such as olfactory pits and otic vesicles. Thus, PCD patterning in zebrafish embryos occurs randomly at early stages and becomes restricted to certain region of the embryos. The spatio-temporal pattern of PCD during the early embryonic development in zebrafish will provide basic information for further studies to elucidate genes involved in. regulation of PCD largely unknown in vivo during vertebrate embryogenesis.

Background : Obvious applications of aloe (Aloe vera) and their rapid intake make it crucial to evaluate their biological impacts to aquatic organisms. Methods and Results : In this study, we investigated the possible effects of aloe extract on zebrafish embryos (Danio rerio) by assessing teratogenic properties including survival rate, hatching success, heart rate and morphological changes for 96hpf (hours post fertilization). We noticed that exposure to aloe extracts (0.1, 10, 50, 100 and 150 μl/ml in embryo medium) to zebrafish embryos showed no alterations in survival and morphological changes when compared to control embryos. In contrast, embryos exposed to 150 μl/ml of aloe extract shows delayed hatching rate at 72hpf when compared to lower concentrations. Similarly, aloe extract at 150 μl/ml exposed embryos elicited significantly reduced heart rate (132 ± 1 beats/min) at 48hpf when compare to control embryos. Conclusion : Based on the above findings, we speculate the teratogenic effect of aloe extract on zebrafish embryos.

Endocytosis of the Notch ligand, DeltaD, by mind bomb1 is indispensable for activation of Notch in cell fate determination, proliferation, and differentiation during zebrafish neurogenesis. Loss of mind bomb1 activity as an E3 Ubiquitin ligase causes the accumulation of deltaD at the plasma membrane and results in the ectopic neurogenic phenotype by activation of Notch in early zebrafish embryogenesis. However, the regulatory mechanism of deltaD during neurogenesis is not identified yet. This study aims to analyze the pathway of mib1 and deltaD after endocytosis in vivo during zebrafish embryogenesis. Mind bomb1 and deltaD are co-localized into autophagosome and mutant form of mind bomb1 fails to cargo deltaD into autophagosomes. These findings suggest that mind bomb I mediates deltaD regulation by autophagy in an ubiquitin-dependent manner during zebrafish embryogenesis.