• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.207-215
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• 2020

In this experiment, investigated toxicity evaluation of chemicals using Asian toad embryos, along FETAX(Frog Embryo Teratogenesis Assay-Xenopus) protocol. Asian toad, Bufo gargarizans embryo incubated and investigation of Benomyl(Germicide), Carbofuran(Insecticide) and Thiobencarb(Herbicide) effect by probit analysis. As a result, depends on the concentrations of Benomyl, Carbofuran and Thiobencarb, along mortality and malformation rates were increases and larval body length were decreased. The teratogenic concentration(EC₅₀) of Benomyl, Carbofuran and Thiobencarb were 1.03, 8.74, 4.98mg/ℓ, respectively. And when exposed to Benomyl, larvae responded most sensitively to malformations. Embryo lethal concentration (LC₅₀) Benomyl, Carbofuran and Thiobencarb were 7.26, 560.72, 16.87mg/ℓ, respectively. And Benomyl were at the lowest concentration of lethal the embryos. The teratogenic index(TI) were 7.05 in Benomyl, 64.16 in Carbofuran and 3.39 in Thiobencarb, thus TI values were above 1.5, which is the criterion of teratogenicity. Three of the pesticides used in this study were considered to be a teratogenic substances and Carbofuran was the most potent teratogen. And more specific researches are needed to investigate the effects of pesticides on the embryo development of toads and amphibians and their mechanism.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.413-419
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• 2011

This study was conducted to find out the cadmium (Cd) accumulation and tolerance of Iris pseudacorus and Acorus calamus as aquatic plants native to Korea for Cd removal in water. In the range of Cd concentration from $10{\mu}M$ to $130{\mu}M$, the Cd lethal dose 50 ($LD_{50}$) was $78.5{\mu}M$ in I. pseudacorus and $47.6{\mu}M$ in A. calamus. In I. pseudacorus, superoxide dismutase and peroxidase as antioxidants were relatively effective against oxidative stress caused by Cd, while catalase, superoxide dismutase, and polyphenolics were effective in A. calamus. The polyphenolics known as typical antioxidants were not detected in I. pseudacorus. In both species, the Cd accumulation in plants increased with the higher Cd concentration and the longer processing period. Also, the absorbed Cd was accumulated mainly in the roots. The amount of Cd accumulated in the shoot part was maximally $548.1mg{\cdot}kg^{-1}$ (82.1% to Cd accumulated in the root part) in I. pseudacorus and $121.4mg{\cdot}kg^{-1}$ (13.7%) in A. calamus, which implied that both species all were enough evaluated as Cd hyper-accumulators based on 0.01% or more Cd accumulation in the shoot. Especially I. pseudacorus showed outstanding ability to move well Cd into the shoots from the roots and high tolerance to Cd stress.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.145-153
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• 1986

For the inactivation of venoms, the chemical methods are generally applied. In the chemical method many works have been carried out with the chemical reagents and immunological antiserums. However, all inhibitory effect of these chemicals acting on snake venomes may well be due not to the specific, but to the nonspecific inhibitory action. Therefore, it is necessary to separate venom into its compositional active proteins and develop specific inhibitor which acts on the each protein. Until now, there have not been any reports about the substance which acts on snake venom as a specific inhibitor. Recently in 1979, we had actually isolated a specific venom inhibitor(ISV) which has a strong inhibitory activity against the proteinase of snake venom of Colubridae. In our experiments described here, a strain of Aspergillus sp., isolated from soil, was able to produce a biological active substance. The partial crystallized substance had a strong inhibitory activity against hemorrhagic action of snake venom of Colubridae. For the inhibitory action of the sample on the lethality of venom, the substance prevented completely the lethal action of the hemorrhagic factor when they were treated with enough amount of the substance. The edema factor of whole venom of Agristrodon bromohoffi brevicaudus was completely inhibited, but those of HR-I and HR-II of Trimeresurus flavoviridis venom were inhibited about 50%, when they were treated with the substance of half amount of venom. On the other hand, from the result of subcutaneous hemorrhage in a rabbit, it was concluded that two kinds of antihemorrhagic substance might be produced by the strain used in this work.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.125-133
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• 2015

Entomopathogenic fungi have been studied to develop for biological control agents as an alternative to chemical control agents in insect pest management. Two Lepidopteran insects, Spodoptera exigua and Plutella xylostella, are serious insect pests infested various crops, but not effectively controlled by commercial chemical pesticides due to its high insecticide resistance. A fungal isolate was isolated from S. exigua larvae collected from green onion field in Andong, Korea. To identify the fungal isolate, 18srRNA sequence for internal transcribed spacer (ITS) and ${\beta}$-tubulin regions were sequenced. The ITS and ${\beta}$-tubulin sequence were highly matched to Beauveria bassiana and morphological characteristics also was fit to known B. bassiana. Finally, isolated fungus has identified as B. bassiana and named B. bassiana ANU1. The result of bioassay, median lethal concentrations were $2.7{\times}10^3$ and $0.9{\times}10^3conidia/ml$ and medial lethal times were 65.6 and 60.8 h to S. exigua and P. xylostella, respectively. B. bassiana ANU1 showed high pathogenicity to two insect pests from $20^{\circ}C$ to $30^{\circ}C$ at 50% relative humidity (RH) and more than 40% RH at $25^{\circ}C$ with $10^7conidia/ml$ of concentration.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.56-60
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• 2000

A study was performed to determine the maintenance conditions of the earthworm, Lumbricus rubellus, for the acute toxicity test. To fine out climatic and soil conditions, the earthworms were maintained in artificial soil consisting of sand, clay mineral and peat at different levels of conditions for 14 days. Lumbricus rubellus led to an increase of biomass at temperature $22{\pm}2^{\circ}C$, soil pH $7.0{\pm}1$ and moisture 40%. And four fungicides were tested for acute toxicities to Lumbricus rubellus, according to the optimum condition. The test earthworms were exposed to each pesticide with various concentration gradients. After 14 days, the number of surviving earthworms and their weight alteration during the test period was determined. The 14-day $LC_{50}$ values for the Lumbricus rubellus, of carbendazim, benomyl, thiophanate-methyl and thiabendazole were determined to be 59, 53, 64 and 36 mg/ kg soil dry weight, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.490-499
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• 2016

In this study, the marine ecological impacts of dephosphorized slag and steel slag on the initial life cycle of the rotifer Brachionus plicatilis and benthic copepod Tigriopus japonicus (in marine trophic structure as a first consumer) exposure to slag extracts have been considered using a marine ecotoxicological assessment. In the results of a screen test on slag extracts, the pH of an undiluted solution was measured to have high alkalinity (pH 8.89-12.16), but a toxic reaction to this undiluted solution before and after aging was divided according to test species. For non-aged slag, the toxic effect ($LC_{50}$) of neonate on B. plicatilis was seen to be severe with dephosphorized slag (20.8 %) than steel slag (63.8 %) with under pH-uncontrolled conditions. The toxic values of dephosphorized and steel slag were estimated to be 35.3 % and 36.0%, respectively, for nauplius with T. japonicus. However, the toxicity of slag extracts before and after aging were different for T. japonicus than for B. plicatilis based on the characteristics of the test materials, with pH-controlled conditions. In conclusion, the results of this study suggest that slag can be relatively stable after aging and may not be likely to influence marine environments, even given repetitive extracting under pH-uncontrolled conditions. This study confirms that a marine ecotoxicological assessment method applied to mechanically activated samples can give an idea of the resistance a marine environment has against the introduction of hazardous materials due to precipitation and weathering.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.1-6
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• 2007

Entomopathogenic nematodes (Heterorhabditis sp. Gyeongsan strain, Steinernema carpocapsae GSN1 strain, S. feltiae Monteri strain, S. glaseri Dongrae strain, S. longicaudum Nonsan strain and S. monticolum Jiri strain) were evaluated for the environmentally sound control of sawfly, Arge captiva, A. pagana pagana and A. similis in the laboratory and pot. The corrected mortality of 3rd instar of Arge captiva larva was 100% at 5 days after treatment with S. carpocapsae GSN1 strain and S. feltiae Monteri strain in Petri dish. The mean numbers of established infective juveniles (Ijs) of S. glaseri Dongrae and S. carpocapsae GSN1 strain in a Arge captiva larva were 10.2 and 4.2 Ijs/larva, respectively. Pathogenicity of S. carpocapsae GSN1 strain was different larval stage, i.e., $LC_{50}$ value of S. carpocapsae GSN1 strain against 2nd, 3rd and 4th instar of A. pagana pagana was 11.5, 9.3, and 8.4 Ijs, respectively. Mortality of Arge captiva, A. pagana pagana and A. similis were 72.5, 85.0 and 85.0% by S. carpocapsae GSN1 strain at the $2{\times}10^9Ijs/ha$, respectively, in the pot.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.312-317
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• 2013

The armyworm, Pseudaletia separata was occurred suddenly in a golf club in Namhae, Gyeongnam province in 2013. Thus, pathogenicity of seven species of entomopathogenic nematodes (Steinernema carpocapsae GSN1 strain, S. glaseri Dongrae strain, S. longicaudum Nonsan strain, S. monticolum Jiri strain and S. siamkayai, Heterorhabditis sp. Gyeongsan strain, and H. bacteriophora Hamyang strain) was evaluated against armyworm on tall fescue in pot and golf course to control this pest environmentally friendly. The pathogenicity against P. separata larvae was significantly different depending on nematode species. The corrected mortality of fifth instar of P. separata was 100% in the treatment with S. carpocapsae GSN1 in 7 days in tall fescue pot. However, there was not different in the mortality of fifth instar of P. separata (80 to 100%) at the rate of 385 to 6,160 infective juveniles (Ijs) ($=2.5{\times}10^2$ to $4{\times}10^5Ijs/m^2$) of S. carpocapsae GSN1 strain in each pot. Corrected mortality of P. separata was 65 and 60% at the rate of $10^5Ijs/m^2$ of S. carpocapsae GSN1 and S. longicaudum Nonsan strain, respectively in the tall fescue of golf course.

• Journal of Aquaculture
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• v.11 no.4
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• pp.429-435
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• 1998

This study compared acute ammonia toxicity in juvenile rockfish and red sea bream. Oxygen concentration affected ammonia toxicity to aquatic animals. Without aeration, the 96-hr $LC_50$ values of $NH_4^+$and un-ionhized ammonia for juvenil rockfish(3.6g, 6.6cm) were 2.61 and 0.09 mg/l, respectively. The 3-hr $LC_50$ values of $NH_4^+$ for the size of 1.9g (5.2cm) and 3.6g (6.6cm) rockfish, and 1.0g (3.8cm) and 2.0g (5.0cm) red sea bream without aeration were 3.96, 3.94, 4.35 and 3.75 mg/l, respectively. When oxygen level was low, larger fish were more susceptible to ammonia toxicity than smaller one because of stress resulted from low oxygen. However, with aeration, the 96-hr $LC_50$ values of $NH_4^+$ for the size of 1.2g (3.9cm) and 2.3g (5.1cm) red sea bream with aeration were 3.84 and 3.90mg/l, respectively. The 6-hr $LC_50$values of $NH_4^+$ for the size of 3.1g (5.9cm) and 6.2g (7.0cm) rockfish with aeration were 3.83 and 3.94 mg/l, respectively. When oxygen level was high, larger rockfish and red sea bream were less susceptible to ammonia toxicity than smaller ones. The 6 hr-or 96 hr-$LC_50$ values of $NH_4^+$for rockfish with reduced ammonia toxicity. In comparing 96 hr-$LC_50$ values of $NH_4^+$ and un-ionized ammonia for juvenil rockfish with those for juvenil red sea bream, the values for rockfish were lower than for red sea bream. This indicates that juvenile rockfish is more susceptible to ammonia toxicity than juvenile red sea bream.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.187-195
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• 2022

Crucian carp, Carassius carassius (Weight 28.1±3.7 g, Length 10.0±1.0 cm) were challenged with Aeromonas hydrophila at 0, 2.0×10⁴, 2.0×10⁵, 2.0×10⁶, 2.0×10⁷ CFU/ml for 2 weeks. The lethal concentration 50 (LC₅₀) at 2 weeks of C. carassius challenged with A. hydrophila was 19.776×10⁵ CFU/ml. In hematological parameters, the hemoglobin and RBC counts were significantly decreased by A. hydrophila challenge, whereas there was no significant change in hematocrit. The inorganic plasma components such as magnesium and calcium were significantly decreased. In organic plasma components, glucose and cholesterol were significantly increased by A. hydrophila challenge, whereas total protein was significantly decreased. In enzymatic plasma components, ALP (Alkaline phosphatase) were significantly increased by A. hydrophila challenge. The results of this study suggest that the A. hydrophila challenge to C. carassius induced the significant physiological changes in the hematological parameters and plasma components as deadly pathogenic bacteria.