• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.98-105
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• 1998

The effect of ammonia on survival and growth of the larval rockfish, Sebastes schlegeli was examined by a static renewal bioassay method. The tolerance of larvae to ammonia toxicity was more sensitive at the early larvae, but increased with the development of larvae. In 14 day-old-larvae after parturition, the mortality with treatment of each concentration of ammonia was 5% at control group and 0.0112 $NH_3$mg/l, whereas it was increased up to 27.5% at exposure group of 0.1230 $NH_3$mg/l with higher concentration. Regression equation between ammonium concentration(X) and mortality(Y) was followed; Y=0.516+3.482 X($r^2=0.4737$, P<0.01). The NOEC(no-observable-effect concentration) and LOEC (lowest-observable-effect concentration) to mortality compared to control group were 0.100 $NH_3mg/l$ and 0.1230 $NH_3$mg/l, respectively and chronic value(ChV) which is the geometric mean of the NOEC and LOEC was 0.1110 $NH_3$mg/l. Body length after 7-days exposure in control group, 0.0112 $NH_3$mg/l and 0.1230 $NH_3$mg/l were 7.8325mm, 7.700mm and 7.05mm, respectively. The NOEC, LOEC and chronic value(ChV) were 0.0335 $NH_3$mg/l, 0.0558 $NH_3$mg/l and 0.0432 $NH_3$mg/l, respectively.

• Korean journal of applied entomology
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• v.50 no.4
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• pp.373-378
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• 2011

The striped fruit fly, Bactrocera scutellata, damages pumpkin and other cucurbitaceous plants. The developmental period of each stage was measured at seven constant temperatures (15, 18, 21, 24, 27, 30, and $33{\pm}1.0^{\circ}C$). The developmental time of eggs ranged from 4.2 days at $15^{\circ}C$ to 0.9 days at $33^{\circ}C$. The developmental period of larvae was 4.2 days at $15^{\circ}C$, and slowed in temperatures above $27^{\circ}C$. The developmental period of pupa was 21.5 days at $15^{\circ}C$ and 7.6 days at $33^{\circ}C$. The mortality of eggs was 17.1% at $15^{\circ}C$ and 22.9% at $33^{\circ}C$, Larval mortalities (1st, 2nd, 3rd) were 24.1, 27.3 and 18.2%, respectively, at $15^{\circ}C$, Pupal mortalities were 18.2% at $15^{\circ}C$ and 23.1% at $33^{\circ}C$. The relationship between developmental rate and temperature fit both a linear model and a nonlinear model. The lower threshold temperatures of eggs, larvae, and pupae were 12.5, 10.7, and $6.3^{\circ}C$, respectively, and threshold temperature of the total immature period was $8.5^{\circ}C$. The thermal constants required to complete the egg, larval, and pupal stages were 33.2, 118.3, and 181.2 DD, respectively. The distribution of each development stages was described by a 3-parameter Weibull function.

• 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.

• Korean journal of applied entomology
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• v.36 no.4
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• pp.341-350
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• 1997

We have now constructed a novel recombinant baculovirus producing fusion protein with Autographa californica nuclear polyhedrosis virus (AcNPV) polyhedrin and Bacillus thuringiensis(Bt) cryIA(c) crystal protein. The fusion protein expressed by the recombinant baculovirus in insect cells was characterized. The N-terminal of cryIA(c) gene of Bt subsp. kurstaki HD-73 was introduced under the control of polyhedrin gene promoter of AcNPV, by fusion in the front of intact polyhedrin gene or by insertion into the HindIII site in polyhedrin gene. The recombinant baculoviruses were named as BtrusI or BtrusII, respectively. Although single transcript from the fusion protein gene was apparently observed. BtrusI was produced the two proteins, 92 kDa fusion protein and only polyhedrin. In addition, fusion protein produced by BtrusI did not form polyhedra. Interestingly, however, the cells infected with BtrusII did not show a 33 kDa polyhedrin band as a cells infected with BtrusI. Cells infected with BtrusII were only produced fusion protein, but the polyhedra formed by fusion protein was not observed. To determine the insecticidal toxicity of fusion protein, therefore, Sf9 cells infected with BtrusI were inoculated to Bombyx mori larvae. Sf9 cells infected with BtrusI that expressed the fusion protein caused larval mortality although the insecticidal toxicity was low. In conclusion, our results clearly demonstrated that the fusion protein with polyhedrin and Bt cryIA(c) crystal protein have a insecticida toxicity.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.231-237
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• 2012

Toxicity of $Ni^{2+}$ and Tebuconazole were investigated via FETAX (Frog Embryo Teratogenesis Assay-Xenopus) protocol using domestic frog embryos. Embryos of Black-spotted pond frog, Rana nigromaculata, were incubated and toxic effects of $Ni^{2+}$ and Tebuconazole were investigated by probit analysis. As a result, mortality and malformation rates were increased and larval body length was decreased in a dose dependant manner of $Ni^{2+}$ and Tebuconazole. The half maximal effective concentration ($EC_{50}$) of $Ni^{2+}$ and Tebuconazole were 0.07, $12.7mg\;L^{-1}$, respectively and the half maximal lethal concentration ($LC_{50}$) of $Ni^{2+}$ and Tebuconazole were 4.2, 39.1, respectively. The teratogenic index (TI) were 61.4 in $Ni^{2+}$ and 3.1 in Tebuconazole, respectively. These results reveals that $Ni^{2+}$ and Tebuconazole suppress the development of Black-spotted pond frog embryos at the low concentration as showing teratogenic effects in other assay system. Therefore, teratogen assay system using the Rana nigromaculata embryos could be useful as a tool to evaluate the toxicity of the pollutants in environment.

• Korean Journal of Environmental Agriculture
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• v.4 no.2
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• pp.108-113
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• 1985

Aerial application tests with a biological insecticide (Thuricide$^{(R)}$) and two low toxicity insecticides, Diflubenzuron (Dimilin$^{(R)}$) and Triflumuron (Alsystin$^{(R)}$) were carried out against the fall webworm (Hyphantria cunea Drury). For experimental application by helicopter, dilutions of 30x and 45x Thuricide, 180x and 240x Alsystin, and 180x Dimilin were utilized. The solutions were applied at a rate of 30 liters per hectare. The results are as follows: 1) All treatments, Dimilin 25% wp, Thuricide wp, and Alsystin 25% wp, were found to very effec tive against fall webworm larvae. Percentages of mortality averaged between 93.9% and 97%. 2) No significant differences in percentages of larval kill were found between dilutions of Thuricide (30x and 45x) or Alsystin (180x and 240x). 3) Assessment of parasite densities in the treated areas 35 days after treatment indicated that percentages of reduction for all five species found, including Brachymeria lasus(Walker) (=obscurata [Walker]), were lower than for areas treated with the conventional insecticide Diplox$^{(R)}$ (trichlorfon) 25% wp. In particular, the percentage of reduction in Thuricide-treated areas was only 21% as compared with the untreated (control) areas. 4) Aerial applications of Dimilin were very effective and economical for control of the fall webworm by comparison with [aerial] applications of Thuricide.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.337-343
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• 2011

In order to know the effects of rearing conditions such as water temperature, salinity, larval stocking density, kinds and amounts of food organism and seedling collection method on seedling production of the brackish water clam, Corbicula japonica, the growth and survival rate of the larvae were investigated at each rearing condition. The shell length of larvae showed faster growth at $24^{\circ}C$ and $27^{\circ}C$, and survival rate showed good results at $18^{\circ}C$ and $21^{\circ}C$. Based on growth and survival rate according to water temperature, the optimal water temperature for larvae rearing was $24^{\circ}C$. At the salinity of more than 3 psu, the growth and survival rate were higher than 0 psu. The optimal salinities for larvae were 6-9 psu. Growth and survival rate of larvae were high at low stocking density and the optimum stocking density of larvae was 10 inds./ml. Daily feeding concentrations of 10,000-20,000 cell/ml of food organisms mixed Pavolva lutheri, Isochrysis galbana and Chaetoceros calcitrans were very effective. Full grown larvae collection from various substratum was significantly higt in sand, especially sand size was less than 0.25 mm.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.113-118
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• 1998

The efficacy of conidia of Beauveria bassiana (Balsamo) Vuillemin strain CS-1 that showed high mortality in laboratory and net house was examined against diamondback moth larvae in the field. Conidia ($4{\times}10^{7}$ conidia/ml) were applied to larvae on chinese cabbage in a 1.5% emulsifiable oil-emulsion amended with 4% clay at a volume of 0.55 L/3.3 $m^{2}$. There were no significant differences among plants and replicates in the deposition of spray droplets on water-sensitive papers or of conidia on leaves and larvae. Weather conditions were rainy and cool during first few days, and then hot and dry. Persistence of conidia was equally short on both leaves and larvae. Nevertheless, treatment of B. bassiana potentially reduced larval populations. But the field efficacy was lower than the laboratory efficacy. This reduced efficacy was ascribed to unfavorable environmental conditions.

• Journal of Aquaculture
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• v.10 no.4
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• pp.473-483
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• 1997

Yolk resorotion and commencement of external feeding in larvae of red spotted grouper, Epinepheus akaara were studied to understand the high mortality of larvae. Consumption of yolk was higher than that of oil globule for the first 24hs after hatching. The resorption rates of yolk and oil globule increased with the increase of temperature. The time yolk was comsumed up to 99% was 84hs after hatching in 23~$25^{\circ}C$,72hs at ~$27^{\circ}C$, and 60hs in 29~~$31^{\circ}C$, while the time for oil globule was 96hs in 23~$25^{\circ}C$, 84hs at $27^{\circ}C$, and 60hs in 29~$31^{\circ}C$. The relationship between mouth openning time (Y) and water temperature (X) was repersented as a linear regression, Y=-2.53X+118.4, (r2=0.89). In 72~96hs after hatching, upper jaw sizes of the larvae reached around 0.114 mm. By the time the larvae comsumed most of the yolk and oil globule, and started external feeding. The relationship between upper jaw length (Y) and total length (X) was represented as a linear regression, Y=0.139X-0.165, (r2=0.88). Rotifer was not found in the guts of larvae before 72hs after hatching at $28^{\circ}C$, when larvae resorbed their yolk and oil globule over 99%. But, at 96hs after hatching, about 33% of the larvae had the rotifer in their guts. Delayed feeding experiments revealed that the earlier food supply within 84hs after hatching showed the better survival rates for the larvae. The larvae fed at 96hs after hatching died all within 120hs.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.706-714
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• 2017

An investigation of the effects of Pb for domestic anuran embryos were evaluated with the Frog Embryo Teratogenesis Assay; Xenopus (FETAX). Depending on the species, the difference between the embryo size and the embryonic development time was determined. As a result, mortality and malformation rates were increased, malformation patterns were changed and larval body length were decreased in a dose dependent manner of the Pb. The half maximal lethal concentration ($LC_{50}$) of the Bufo gargarizans, Hyla japonica, Rana nigromaculata and Bombina orientalis were 0.58, 0.49, 0.52, $0.54mg\;L^{-1}$, respectively. The half maximal effective concentration ($EC_{50}$) of the Bufo gargarizans, Hyla japonica, Rana nigromaculata and Bombina orientalis were 0.35, 0.74, 0.30, $0.29mg\;L^{-1}$, respectively. The teratogenic index (TI) were 1.66 in the Bufo gargarizans, 1.81 in the Hyla japonica, 1.73 in the Rana nigromaculata and 1.86 in the Bombina orientalis, respectively. Therefore, the Pb seems likely to have a teratogenic effect in all four species' embryonic development. The Bombina orientalis was the most sensitive to the Pb. This means that the difference between the different species, even if they have all been exposed to the same concentration of pollutants depending on the species. The result above show that the Pb acts as a teratogenic agent in the development of the four domestic frog species.