• Korean Journal of Environmental Biology
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• v.30 no.4
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• pp.287-306
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• 2012

Amphibian population declines globally. Environmental contamination by heavy metals has been suspected to the one of the reason for distinction of amphibian which has obligate aquatic life style during larval period. Amphibians have been widely accepted as animal model for the study of endocrine disruption in aquatic ecosystem at molecular as well as individual levels. There are increasing need for toxicological data in amphibians at multiple endpoints for management of contamination and development of safety guidelines. Here, we reviewed toxicological information about toxicity of heavy metals (arsenic, cadmium, chromium, copper, lead, mercury, nickel, zinc) on various end-point of amphibian.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.705-711
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• 2016

In this experiment, embryos of Asian toad, Bufo gargarizans, were investigated to evaluate toxicity of chemicals along FETAX(Frog Embryo Teratogenesis Assay-Xenopus) protocol. Asian toad, Bufo gargarizans, embryos incubated and investigation of Zn and Benomyl effect by probit analysis. As a result, depends on the concentrations of Zn and Benomyl, mortality and malformation rates were increases and larval body length were decreased. The teratogenic concentration($EC_{50}$) of Zn and Benomyl were 2.3, $1.0mg/{\ell}$, respectively and the embryo lethal concentration($LC_{50}$) Zn and Benomyl were 10.3, 6.9, respectively. The teratogenic index(TI) were 4.4 in Zn and 6.7 in Benomyl, thus showed teratogenicity in embryonic development of B. gargarizans. These results reveal that Zn and Benomyl in this experiment suppressed the development of embryos at relatively low concentration. Much of B. gargarizans embryos can be secured, and easy to incubate. In addition, mortality, malformation ratios, malformation patterns and growth rates are similar to the results from the other assay systems. Therefore, the B. gargarizans embryo teratogenesis assay system could be a useful tool to evaluate toxicity of pollutants in environment.

• Journal of fish pathology
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• v.26 no.1
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• pp.11-17
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• 2013

The cadmium (Cd) toxicological effects on the fertilized eggs, embryos and larvae were investigated in olive flounder, Paralichthys olivaceus water-borne exposed to Cd. The survival rate and hatching success of the embryos significantly diminished in treated groups in dependence of the Cd concentration. Significant differences were found at ${\geq}30{\mu}g\;L^{-1}$ exposed groups compared to the control group. A significant increase of malformation of the embryo was observed at ${\geq}20{\mu}g\;L^{-1}$ exposed groups. They usually include such symptoms as clouded yolk-sac abnormality, fin erosion and spinal curvature. A significant reduction in the survival rate of the larvae was observed in ${\geq}20{\mu}g\;L^{-1}$ exposed groups with accompanied by the disorder. Notably, in larvae, a concentration as low as $10{\mu}g\;L^{-1}$ exposed groups caused significant elevated abnormalities that is incidences of spinal cord deformation, abnormal eyes, deformation of the head region and severe developmental delay.

• Journal of Aquaculture
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• v.16 no.4
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• pp.240-244
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• 2003

The primitive gonad development in Paralichthys olivaceus was classified into (ⅰ) primordial germ cell (PGC), (ⅱ) genital ridge type (GRT), (ⅲ) primitive gonad type I (PGT I) and (ⅳ) primitive gonad type II stages. In the control group, PGC was recognizable on the 3rd days after hatching, and the primodial gonad after 24th days, while it was around the 22nd day after hatching in the group exposed to PCBs 3.0 $\mu\textrm{g}$/L for 30 days. Likewise, the progress of kidney development was recognized in four stages; unitubular type of mesonephric duct (UTMD), the branched mesonephric duct (BMD), convoluted tubule formation (CTF) and glomerulus appearing (GA) stage. It was structurally completed between the 25th and 30th day after hatching in two groups. There was no significant difference (p>0.05) in the time scale of development of gonad, and kidney between control and the PCBs - exposed group.

• Korean journal of applied entomology
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• v.19 no.2 s.43
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• pp.79-83
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• 1980

The toxicities of some soil insecticides were evaluated in terms of the tolerance to various larval-ins tars of the common cutworm (Agrotis fucosa Butler) using topical application method in the laboratory. $LD_{50}$ values(ug/larva) were determined by the probit analysis and the tolerance-values were obtained with '$LD_{50}$ values for from 2nd-to 6th-instars/$LD_{50}$ values for first-instars.' The relative toxicities of the insecticides were 31so compared with the $LD_{50}$ values for the instars. The degree of tolerance was greatly increased as the larval instar advanced; the ranges of tolerance between the first-and 6th-instar larvae to the insecticides phoxim (Volaton), diazinon, chlorpyrifos (Dursban), carbofuran (Curaterr) and Mocap were 251.6, 126.6, 97.5, 44.3, and 18.7 times, respectively. The average relative toxicities of the insecticides for the instars indicated that the toxicity of phoxim was the greatest and following carbofuran, chlorpyrifos, Mocap and diazinon.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.103-112
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• 2011

Aquatic contamination by organic pollutants has been a suspected reason for rapid decrease of amphibian populations whose embryonic and larval stages are in an aquatic environment. Amphibian embryos can be a useful model to study the ecoctoxicologial impacts of aquatic pollutants. The obtained toxicological data are useful references for the management of aquatic pollutants in public health because amphibia share many developmental events with terrestrial vertebrates including humans. Safety guidelines for the toxicological effects of aquatic contaminants of chemicals identified as hazardous should be addressed at multiple endpoints. Alkylphenols have been widely-used in agricultural, industrial, and household activities; they contaminate and can persist in aquatic environments. Exposure to alkylphenols results in endocrine disruption in aquatic animals. In this review, we summarize the developmental toxicities of alkylphenols in amphibian embryos and larva according to the exposure route, chemical concentration, duration of exposure, and affected developmental stage together with mechanisms of toxicity and typical patterns of developmental abnormality. The merits of amphibian embryos as a toxicity test model for mid- to long-term exposure to aquatic pollutants are discussed proposed.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.50-56
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• 2003

A freshwater bloom-forming cyanobacterium, Microcystis aeruginosa, and local soil isolate Scytonema sp. strain BT 23 were demonstrated to contain biotoxic secondary metabolites with pesticidal and mosquito larvicidal activities. A purified toxic constituent from M aeruginosa showed an absorption maximum at 230 nm and its toxicity symptoms, Rf value on TLC, and retention time observed ill an HPLC analysis were similar to those of the hepatotoxic heptapeptide microcystin-LR. The bioactive constituent of the Scytonema sp. was less polar in nature and exhibited two peaks at 240 and 285 m. When applied to two cruciffrous pests, Pieris brassicae and Plutella flostella, the crude extracts and toxic principles from the two cyanobacteria showed significant antifeedant activity in a no-choice bioassay, and at higher concenuations exhibited contact toxicity to the insect larvae. The purified toxin from M. aeruginosa was found to be more effective and produced 97.5 and $92.8\%$ larval mortality in the two pests, fo11owing 2 h of toxin treatment at a concentration of $25{\mu}g$ Per leaf disc (2.5 cm dia.). Meanwhile, similar treatment with the purified toxin from Sytonema sp. stain BT 23 only produced 73 and $78\%$ mortality in the two pests. The cyanobacterial constituents also showed significant activity against Culex and Anopheles larvae. The M. aeruginosa toxin ($20{\mu}g\;ml^-1$) caused 98.2 and $88.1\%$ mortality in the Culex and Anopheles larvae, respectively, while the purified toxin from the Sytonema sp. was less toxic and only produced a 96.3 and $91.2\%$ mortality, respectively, at a much higher concentration ($40{\mu}g\;ml^-1$). Accordingly, the current results point to certain hitherto unknown biological properties of cyanobacterial biotoxins.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.661-667
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• 2015

Vibrio harveyi is one of the most serious pathogens causing vibriosis in larval and grow-out shrimp culture. This study was performed to investigate the bactericidal effect of a monopersulfate compound against V. harveyi and its toxicity in Litopenaeus vannamei. The monopersulfate compound was prepared at 0, 0.15, 0.3, 0.6, 1.2, and 2.4 ppm for the bactericidal efficacy study, and then V. harveyi was added at a rate of 1×10⁶ CFU/mL. Subsequently, five shrimps/dose were added to the water bath. The other groups of shrimp were exposed to monopersulfate, but not to the bacterium. None of the shrimps exposed to any of the monopersulfate treatment doses without bacteria died, and no changes in their movement were detected for 7 days. However, shrimps exposed to bacteria without monopersulfate showed decreased movement and lethargy, but no death. The total number of other bacteria and V. harveyi at the different concentrations decreased significantly by 4-6 log values compared to that in the bacterial control group. The monopersulfate compound completely inhibited V. harveyi growth beginning 1 h after exposure to 2.4 ppm. These results show that the monopersulfate compound is an efficient disinfectant against naturally occurring marine bacteria and V. harveyi without being toxic to shrimp.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.1
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• pp.50-60
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• 2012

This study was carried out to evaluate the ecotoxicological effects of Alum and Ferric chloride on the population of Eisenia fetida in vermicomposting of sewage sludge. Using contact filter toxicity test, it was shown that LC50 of Alum and Ferric chloride on adult Eisenia fetida were 457.4 mg $kg^{-1}$ and 1,665.2 mg $kg^{-1}$, respectively,which meant Ferric chloride had much higher acute toxicity on earthworm than Alum. Alum didn't affect on cocoon production, hatchability and number of hatched larvae of Eisenia fetida. Ferric chloride didn't have any efects on number of hatched larvae per cocoon, but reduced cocoon production and hatchability. Larval density of next generation was reduced by the food containing Alum and Ferric chloride. Above results indicated that the Alum and Ferric chloride could be one of the hazardous materials that made extinction of earthworm population when the sewage sludge treated with Alum and Ferric chloride was supplied to the earthworms.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.15-24
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• 1972

During the autumn-rearing season of 1971, at the silkworm rearing house at the college of agriculture, Seoul national university in Korea, the authors carried out a series of experiments (1) on the susceptibility of four important silkworm pathogens (Aspergillus flavus, Bacillus thuringiensis, Aspergillus oryzae, and Isaria farinosa) to Halamid (Tosylchloramide Sodium), (2) on the acute toxicity of Halamid to silkworm larvae at every instar, (3) on the inhibiting effect of Halamid to the attack of two silkworm infections, fungal muscardine and viral jundice, and the chronic toxicity of Halamid to silkworm larvae, and (4) on the yield and quality of the raw silk harvested from the Halamid treated silkworms. As the results of the experiments the authors found that Halamid could be applied usefully to silk worm rearing industry as an effective disinfectant for both silkworms themselves and their envir onmental articles, rearing houses and tools, also that Halamid exerts its disinfectant effect most efficiently as a disinfectant for silkworms when sprayed in 2% or 3% aqueous solution every second day throughout all tile instars of larval stage.