• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.96-101
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• 2004

The effects of the ecdysteroid agonist tebufenozide on the larvae of Chironomus flaviplumus and Chironomus riparius were tested in the laboratory. Employing a static exposure setup, chironomids were subjected to various tebufenozide concentrations. In the most treatments it reach-ed a statistically significant difference from the control condition. As the concentration of tebufenozide was increased, a relatively larger proportion of the observed mortality was associated with the metamorphosis and molting process. The larval mortality of C. riparius was high in C. flaviplumus during over 30 ${\mu}g\;L^{-1}$ treatments. In terms of development, the effects of tebufenozide were delayed growth stage in relatively lower concentration such as 10 ${\mu}g\;L^{-1}$ tebufenozide treatments. The rates of succeed adult through the molting process were various in treated concentrations or/and the species.

• Korean Journal of Environmental Biology
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• v.26 no.1
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• pp.36-41
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• 2008

Induction of morphological deformities in Chironomus riparius larvae was assessed after exposure to 0.3, 1, 10 and 30 ${\mu}g\;L^{-1}$ potential endocrine disruption chemicals, Diethylhexyl phtalate (DEHP). We observed and subdivide types of mentum deformities and counted the incidence of mentum deformities. The mortality was not increased according to concentrations of DEHP, while was depend on the exposed days. The incidence of mentum deformities for MLT (median lateral teeth), LT (lateral teeth), and MIX (MLT+LT) of the mentum morphological structure showed MLT (2.8$\sim$11.4%)>LT (2.8$\sim$2.9%)>MIX (2.8$\sim$3.0%). The type of mentum deformities on C. riparius was classified six groups following exposure to DEHP. The incidence rate was occupied following to tooth addition (4.3%), tooth split (2.8%), tooth deletion (2.4%), tooth fusion (1.4%), $K"{o}hn$ gap (0.5%) and abnormal shape (0.5%). Especially tooth split and tooth fusion were observed in DEHP treated conditions.

• Journal of Environmental Health Sciences
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• v.29 no.2
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• pp.7-15
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• 2003

Di-2-ethylhexyl phthalate (DEHP), is a widely used plasticizer known to be a suspected endocrine disrupter, but its exact effects on aquatic organisms are not yet known. When Japanese medaka (Oryzias latipes) were exposed from the time of hatching to 3 months of age to an aqueous DEHP solution at nominal concentrations of 1, 10, and 50 $\mu\textrm{g}$/l, DEHP treated female fish showed distinct reproductive effect. And the midge (Chironomus riparius.). an aquatic invertebrate, was exposed to DEHP to evaluate the effects on reproductive processes via sediment toxicity. The test endpoints included emergence, sex ratio, fecundity, and the viability of F1 offspring egg ropes. The result implied that the normal developmental and/or reproductive processes in C. riparius had been disrupted when exposed to DEHP, the effect also being displayed in the next generation. In summary, DEHP hinders the development of reproductive organs in the female Japanese medaka and C. riparius.

• Korean Journal of Environmental Biology
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• v.23 no.4
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• pp.357-361
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• 2005

The exposed strain of C. riparius treated with di (ethyl- hexyl)-phthalate (DEHP) did not result in a consistent relationship between mortality or sex ratio and chemical concentrations. And after treating with DEHP, the emergent female from the exposed strain appeared to be fatty with a large body volume comparing with the non - exposed strain. The emergent period (EP) was especially different between the exposed fourth strain and the non-exposed strain; generally the exposed strain was $7\~10$ days, and non - exposed strain was $17\~24$ days. Regarding sustainable exposed effects, the EP, the first emergent day (FED), and the body volume (BV) could be suggested as suitable bio - markers for detecting of exposure to various EDCs.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.532-536
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• 2004

Due to the fourth-instar larvae of C. riparius have a sensitive to ecdysteroidal molting hormones for the life cycle developments, accordingly the emerged adult affected corresponding to larval phase's environments. The emerged female from larval phase exposure to DEHP observed a fact body and clumsy fling behavior in females. The body volume of treated female groups was clearly larger than that of control fe- males. In the 2D/E gel 1108 protein spots were identified. The visualized protein spots allowed extraction of 27 protein spots differed more than 3 fold in DEHP treated animals, which was approximately 2.4％ of the total protein spots. In this view, the body volume (or morphological characters) was well observed and detected faster than physiological detection for various EDCs. In this study, the body volume as a detecting po-int for EDCs suggested a bio-marker in individual levels.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.269-274
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• 2005

The 2D/E gel analysis for polypeptide expression reflecting I-18 C gene (early-ecdysterone inducible gene) has conducted the emerged C. riparius adults from larval phase exposure to tebufenozide acting as an ecdysteroidal molting hormone. Control group, the amount of ORE II of the I-18 C gene was larger than that of ORE I of this gene. After treatments, ORE I of the I-18 C gene was overexpressed as the polypeptide, whereas ORF II of this gene was expressed as the polypeptide and was clearly reduced expression. Accordingly, we consider that tebufenozide exhibited endocrine disruptions related processing of ecdysteroid receptor protein reflecting ORF II of I-18 C gene. Also, earlier emergence day was related overexpressed polypeptide reflecting ORE I of I-18 C gene. In this study result, tebufenozide induced changing of physiological condition, and then polypeptide expression reflecting early-ecdysterone inducible I-18 C gene was different between control group and exposure group.

• Environmental Analysis Health and Toxicology
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• v.21 no.4 s.55
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• pp.301-310
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• 2006

본 연구에서는 내분비계장애물질로 잘 알려진 Bisphenol A와 Ethynyl estradiol(이하 BPA, EE)이 Chironomus riparius에 미치는 영향을 알아보고자 하였다. 수생생태계에서 Chironomus의 생태학적 중요성을 고려하여 연구한 반수치사농도(LC50),효소 활성, 성장/발달 등의 생화학적, 생리학적 독성에 대한 연구는 이들 물질에 대한 잠재적인 생태학적 중요성을 이해하는데 있어 유용한 정보를 제공할 수 있을 것이다. 연구 결과 BPA와 EE에 노출된 후 C. riparius게서 CAT와 GST활성이 증가하였고, EE에 고농도로 노출된 후 성충까지 충분히 성장하지 못했음을 확인하였다 이러한 결과로부터 C. riparius에서 BPA, EE에 대한 중요한 독성정보를 얻을 수 있었다. 그러므로 앞으로 BPA와 EE의 생화학적 효과와 C. riparitis의 개체수준 이상에서의 생리학적 실험을 통한 검증이 필요할 것이다.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.165-172
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• 2020

Heavy metals are common pollutants in the freshwater environment and have toxicological effect in habitat organisms. The heavy metals highly accumulated in sediment and organism, and observed various physiological responses. In this study, we investigated the molecular response to heavy metal toxicity (Al, Aluminum; Cr, Chromium; Cu, copper; Mn, Manganese; Zn, Zinc) through expression of heat shock protein 40, 70, 90 (HSP40, 70, 90), cytochrome 450 (CYP450), Glutathione S-transferase (GST) and Serine-type endopeptidase (SP). HSPs showed up-regulation in Cu and Zn exposures. Furthermore, HSPs expression in treated groups tended to be higher than the control group. The tendency of CYP450 and GST mRNA expression was higher for Cr and Cu than for other exposure group. The expression of SP gene was low at Al exposure and other group were measured to be similar to control. These results suggest that heavy metal toxicity in freshwater ecosystem may affect physiological and molecular process. Also, the comprehensive gene expression in the aquatic midge Chironomus riparius give useful information to potential molecular biomarkers for assessing heavy metal toxicity.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1999.05a
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• pp.56-56
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• 1999

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.256-261
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• 2009

Molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate), a selective, preemergence thiocarbamate herbicide used for grass weed control in rice fields, is being most widely used in Korea. This study was conducted to assess the comparative toxicity of molinate on two aquatic insects, Chironomus riparius and Cloeon dipterum in four larval stages. First-instar larvae of C. riparius appeared to be the most sensitive to acute exposure of molinate with a 48-h $EC_{50}$ of 7.8 mg/L, followed by third instar (48-h $EC_{50}\;=\;22.9\;mg/L$), second instar (48-h $EC_{50}\;=\;25.0\;mg/L$) and fourth instar (48-h $EC_{50}$ > 50 mg/L) larvae. Also, the sensitivity of the larvae of C. dipterum was presented as the same manner of the larvae of C. riparius. The youngest group of larvae of C. riparius appeared to be the most sensitive to molinate, with 96-h $EC_{50}$ values ranged from 14.3 to 24.1 mg/L. The authors assume that the young instar lavae of aquatic insects, Chironomus riparius and Cloeon dipterum are more sensitive to molinate. Also, the authors propose that Mayfly, Cloeon dipterum is well suited as a bioassay organism because it is one of the most vulnerable aquatic insects inhabiting agricultural ecosystem in Korea.