• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.391-396
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• 2009

The biological effects of carcinogenic polycyclic aromatic hydrocarbons (cPAHs) including benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DBA), benzo[a]anthracene (BaA), benzo[b] fluoranthene (BbF), benzo[k]fluoranthene (BkF), and indeno[1,2,3-c, d]pyrene (InP) on transcriptomic changes were determined in the liver of Oryzias latipes. Differentially expressed genes (DEGs) by binary exposure to cPAHs (BaP+BaA, BaP+BbF, BaP+BkF, BaP+DbA, BaP+InP) were screened by annealing control primers-based polymerase chain reaction followed by sequence analysis and BLAST searching. The results showed that four DEGs were commonly expressed by cPAHs and they were identified as ribosomal protein S4, coagulation factor II, elongation factor 1 beta, and a predicted protein similar to human immunodeficiency virus type I enhancer binding protein 3. This finding suggests that binary exposure to cPAHs interferes protein synthesis required for fundamental liver functions in fish.

• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.132-137
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• 2008

Differential gene expression profiling was carried out in the hepatic tissue of medaka fish, Oryzias latipes, after exposure to an organophosphorus pesticide (OPP), Iprobenfos (IBP), a widely used pesticide in agri- and fish-culture, using a medaka cDNA micro array. Twenty six kinds of differentially expressed candidate genes, with 15 and 11 induced and repressed in their gene expressions, respectively, were associated with cytoskeleton (3.8%), development (7.7%), immune (7.7%), metabolism (30.8%), nucleic acid/protein binding (42.3%) and reproduction (7.7%). Of these genes, changes at the transcription level of five were re-evaluated by real-time quantitative PCR (qRT-PCR). Considering the known function of authentic genes, the effects of IBP on the biological activity and pathological aspects in medaka fish were discussed. The identified genes could be used as molecular biomarkers for biological responses to OPPs contamination in an aquatic environment.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.453-461
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• 2009

Killifish (Oryzias latipes) were exposed to an organophosphate pesticide, pirimiphos-methyl, in a flow-through system to determine the bioconcentration factor (BCF) following GLP (Good Laboratory Practice). This study was conducted at two different concentrations (1 and $10\;{\mu}$g/L) of $^{14}C$-labeled pirimiphos-methyl for 28 days uptake and 14 days depuration according to the OECD 305 test guideline. The $BCF_{ss}$ for total radioactive residues in whole fish were 1,251 and 1,277 for low and high concentrations, respectively. The $BCF_k$ based on the uptake and depuration rate constants were 1,200 for both low and high concentrations. During the depuration phase, the accumulated test substance was rapidly depurated from fish. Greater than 95% of the residue at steady-state was depurated after 2 days. Although the measured BCF values were high, pirimiphos-methyl could be evaluated as a low risk from bioaccumulation by aquatic organisms due to the short depuration period and low amount of bound residue (1.5%). We suggest that in evaluating bioaccumulation, not only the BCF should be considered, but also depuration time and bound residue in aquatic organisms give an indication of the potential environmental risks.

• Environmental Analysis Health and Toxicology
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• v.14 no.3
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• pp.81-85
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• 1999

Diazinon, an organophosphate pesticide, is relatively highly toxic to fish and causes vertebral malformation and behavioral change of fish at relatively low concentrations. To elucidate biochemical mechanism of the behavioral change of Oryzias latipes (killifish) caused by diazinon, the effect of the insecticide on acetylcholine esterase activities and the levels of some neurotransmitters were evaluated. Acetylcholine esterase activities in both head and body were significantly lowered at the concentration of 10 ppb of diazinon and acetylcholine contents in head tended to be upregulated with increasing concentration of diazinon. Exposure of killifish to 5000 ppb diazinon resulted in gradual decrease in acetylcholine content in body part with exposure time. Norepinephrine and serotonin concentrations in killifish head and body were highest at 1000 ppb of diazinon while neurotransmitter were relatively low in fish unexposed or exposed to lower dose of the pesticide, suggesting that increased norepinephrine and serotonin can partially account for diazinon-induced behavioral abnormality.

• Environmental Analysis Health and Toxicology
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• v.18 no.1
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• pp.21-25
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• 2003

카바메이트계 농약인 카보푸란은 어류에 대한 독성이 매우 높으며, 낮은 농도에서 어류의 척추기형이나 행동이상을 유발한다. 이러한 카보푸란의 독성기전을 밝히기 위한 일환으로 신경물질대사와 관련이 깊은 acetylcholine esterase(AChE)와 monoamine oxidase(MAO)에 미치는 농약의 효과를 송사리(Oryzias latipes; Medaka fish)를 이용하여 평가하였다. Medaka fish에 대한 카보푸란의 반수치사농도(LC$_{50}$)는 2.5 ppm이었으며, 1 ppb 카보푸란에 24시간 노출된 경우, AChE 효소활성이 머리와 몸통부위에서 각각 30, 20%씩 감소되었다. 한편, MAO 효소활성은 카보푸란의 농도가 증가함에 따라 머리부위에서는 감소한 반면, 몸통부위에서는 증가하는 경향을 보였다. 특히 카보푸란의 농도가 1 ppb에서도 송사리의 MAO 효소활성이 영향을 받는 것으로 나타나, 카보푸란에 의한 송사리의 행동이상은 AChE 활성 뿐 아니라 MAO활성의 변화에 의한 복합적인 효과일 가능성이 높다.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.220-225
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• 2008

In this study, alterations in whole proteome expression patterns in the head of Japanese medaka (Oryzias latipes) was investigated following acute or chronic exposure to benzo(a)pyrene (BaP) (25 ${\mu}g$ L$^{-1}$) for 48 hrs and 15 days, respectively. The results showed that 9 and 6 protein spots were statistically different, relative to controls, in response to acute and chronic BaP exposure, respectively. In the acute exposure group, 5 spots were up regulated and 4 spots were downregulated, while in the chronic exposure group, 4 spots were upregulated and 2 spots were downregulated. Three of these spots were common to both the acute and chronic BaP exposure groups and were identified using LC-MS/MS followed by database searching. These 3 spots were found to be associated with structural proteins belonging to the actin and keratin families. These data suggest that acute and chronic exposures to BaP may affect tissue morphology in the head of Japanese medaka.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.23-24
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• 2003

The goal of this study is to develop a biomarker used in monitoring abnormal behaviors of Japanese medaka (Oryzias latipes) as a model organism caused by hazardous chemicals. Japanese medaka was treated by copper and fluoranthene of appropriate sublethal concentrations after starvation for 48 hr. In this study we investigated neural toxicity of copper and fluoranthene in Japanese medaka (Oryzias latipes) along with comparative analysis of corresponding behavioral responses. The untreated individuals showed common behavioral characteristics (i.e., smooth and linear movements). Locomotive activity of the fish was monitored using an image processing and automatic data acquisition system. When treated with copper (100 ppb), the fish showed shaking patterns more frequently. As the concentration of copper increased to 1,000 ppb, activity decreased, and the fish showed an erratic movement. The treated with fluoranthene, however, showed stopping and abrupt change of orientation (100 ppb), and severely reduced locomotive activity and enhanced surfacing activity (1,000 ppb).

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.293-303
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• 2005

Japanese medaka, Oryzias latipes is widely distributed in the North East Asia including Korea, Japan and east China, and commonly used for freshwater toxicity tests and cytotoxicological studies worldwide. In this study, a series of experiments were conducted to identify the potential of the fish as a standard test species for saltwater toxicity evaluation such as marine receiving waters, ocean-dumped materials and sediment pore waters etc. Hatching, growth and mortality rates of the fish were estimated with the wide ranges of salinity from freshwater to seawater (35 psu). Direct exposure of the fertilized eggs in freshwater to the wide ranges of salinity (from 0 to 35 psu) without pre- acclimation to the saltwater revealed no significant differences in hatching rates by salinities (p =0.24). On the other hand, medaka larvae hatched in freshwater and exposed to saltwater directly showed high mortality at > 25 psu treatment groups (p < 0.0001). However, there was no significant difference in mortality of medaka larvae hatched in 13.8 and 14.2 psu at the wide ranges of salinities ($0\~35$ psu). Growth rates of medaka larvae hatched in the above two salinities showed no differences in body length either from 0 to 35 psu treatment groups (p =0.64 for 13.8 psu group and p=0.32 for 14.2 psu group). The number of gill chloride cell in medaka larvae sharply increased when the larvae were exposed to high salinity. Reference tests with zinc chloride revealed 96h $LC_{50}=8.84(7.19\~10.87)mg\;L^{-1}$ using 7~10 day old medaka larvae. These were comparable or better sensitivity in comparison with the other standard test species such as North American sheepshead minnow Cyprinodon variegatus. Based on the results of these experiments, hatching rates and larvalmortality of medaka must be good toxicity parameters for seawater bioassay and the species seems to be a good standard species for both the freshwater and seawater toxicity test.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.254-260
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• 2007

In order to evaluate the toxic effects of butachlor, a herbicide widely used for control of weeds in paddy field, on medaka (Oryzias latipes), acute toxicity tests for five developmental stages and early life stage toxicity test of were conducted. As the results of acute toxicity test, $96h-LC_{50}s$ for 1 day, 1 week, 2 weeks, 2 months and 5 months after hatching of O. latipes were 0.68, 0.52, 0.38, 1.09 and $0.45\;mg\;L^{-1}$, respectively. This indicated that the most sensitive stage was 2 weeks after hatching. The early life stage toxicity test showed that no statistically significant hatching period and hatching success of embryo was observed at all concentrations of butaclor. However, 0.05 and $0.1\;mg\;L^{-1}$ of butachlor showed statistically significant post hatching survival with p<0.1. Abnormalities of larva were 2.1, 2.3 and 10% at 0.025, 0.05 and $0.1\;mg\;L^{-1}$ of concentration, respectively. They showed abnormal vertebral axis, craniofacial alteration and retarded yolk-sac resorption. The total length and weight were decreased depending on butachlor concentration the end of test. Weight of larva was showed more sensitive toxic indicator than total length. The toxicological responses of O. latipes to butachlor expressed as LOEC(lowest observed effect concentration), NOEC(no observed effect concentration) and MATC(maximum acceptable toxicant concentration) values were 0.025, 0.013 and $0.018\;mg\;L^{-1}$, respectively.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.78-83
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• 2012

The recommended species in fish acute toxicity test for pesticide registration in korea are common carp (Cyprinus carpio), killifish(Oryzias latipes) and loach(Misgurnus anguillicaudatus). But most of fish toxicity was evaluated using common carp. The common carp has several problems such as difficulty of room breeding, difference of sensitivity to breeding condition, limited experimental period, etc. For that reason, it is necessary to reexamine of test species. The present study investigated the sensitivity and correlation of $LC_{50}$ values that determined using the acute toxicity test with common carp and killifish. And this study is a realistic approach to evaluated appropriate species for fish acute toxicity test of pesticide. As a result, correlation coefficient(R) of the commom carp and killifish was high correlation of 0.8480 and the $LC_{50}$ values was not significant in the interspecies sensitivity. When the $LC_{50}$ values of common carp and killifish was compared with fish toxicity guideline in Korea, fish toxicity class has fluctuated in 18 pesticides with not very special tendency. Therefore, it is necessary to review of killifish has more advantage to standardization of fish culture and in the side of correlation and sensitivity of acute toxicity.