• Journal of Aquaculture
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• v.6 no.4
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• pp.295-310
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• 1993

As a part for the development of effective mass production techniqne of the puffer, Takifugu rubripes. seedfish, an investigation was carried out in 1989. 1991 and 1992 to determine the optimum starting feeding time of rotifers as a starting food for the fish larvae, and to find out the influences of the light intensitiy and LD cycles on the Artemia consumption by the larvae. The optimum starting time of feeding with rotifer. Brachionus Plicatilis was 2nd to 5th day from hatching resulting in survival of $96.5\~90.0\%$. Optimum light conditions for maximum feeding for fish larvae with Artemia were 1000 lux in 6mm, 600 lux in 8mm, and 200 lux in total length of 10-12 mm larvae. Relationship between total length (X: mm) of fish (6-12 mm in total length) and light intensity (Y: lux) for maximum feeding was:Y=2200-200X (r=-1.000). Relationship between days from hatching (X) and total length (Y: mm) of puffer fry was :Y=1.6427+0.2540X(r=0.9814) for 3 to 36 days after hatching, Y=-33.1452+1.1867X(r= 0.9854) for 36 to 68 days after hatching. Survival rate for 68 days after hatching was $24.1\%$ and the range of water temperature during this period was $21.25\pm1.67^{\circ}C$.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.55-65
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• 2018

This study was conducted to clarify diet items and predatory behavior of American bullfrog (Lithobates catesbeianus) according to the sex, maturity and season from April to September 2014 at Gahang wetland of Changnyeong-gun, Gyeongsangnamdo province, Korea. We examined the stomach contents of L. catesbeianus using a gastrectomy technique and identified the contents to a genus or species. The examination showed that large and heavy individual of L. catesbeianus fed on larger amounts of food. However, there were no statistically significant differences in predation amount according to the sex and maturity of L. catesbeianus. The main diet item of during the study period was mostly Insecta (average population rate of 65.5%), followed by Crustacea (13.5%) and Gastropoda (7.9%). The most preferred diet item of L. catesbeianus was Muljarus japonicus. Surprisingly, L. catesbeianus also foraged Parus major, Apodemus agrarius, and Crocidura lasiura. Ths findings showed that L. catesbeianus directly disturbed the wetland ecosystem. We expect the results will be the important reference data for checking the impact of L. catesbeianus, which is designated as invasive species by the Ministry of Environment, on wetland ecosystem.

• Korean journal of applied entomology
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• v.41 no.1
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• pp.55-60
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• 2002

Predation amount and density suppression ability of three species of phytoseiid mites (one native, Amblyseius womersleys Schica; two introduced species, Amblyseius fallacis Garman and Typhlodromus occidentalis Nesbit) on Panonychus citri McGregor were examined in laboratory condition (25$\pm$1$\^{C}$, RH 65$\pm$5%, 16L:8D). A. fallacis and T. occidentalis consumed 20.1 and 9.1 eggs of P. citri, respectively, whereas A. womersleyi consumed 1.1 eggs. When each larva, protonymph and deutonymph of P. citri were supplied as prey for 24 hours. A. womersleyi consumed 23.8, 16.5 and 9.0, and A. fallacis consumed 26.1, 18.2 and 7.4, respectively. However, T. occidentalis consumed only 7.8, 4.2 and 4.2. respectively Density suppression ability of A. womersleyi and A. fallacis against P. citri was very high at the release ratios of 20 : 1 (prey : predator). However, T. occidentalis did not regulate P. citri population effectively Developmental periods from egg to adult of A. womersleyi and A. fallacis was 6.1 and 5.9 days at 25$\^{C}$, respectively.

• Journal of Wetlands Research
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• v.20 no.3
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• pp.272-280
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• 2018

Existing toxicity assessment researches were rarely studied on assessment of the abnormal behavior that affecting survival. Therefore, the study used anti-predator response of amphibians larvae, based on behavioral understanding, to assess toxicity in fullerene nanowhisker(FNW) and fullerene nanowhisker-silver nanoparticle composites(FNW-Ag). The experiment was conducted by dividing the groups not exposed to nanomaterials and exposed to nanomaterials at five concentrations(FNW: $10{\mu}g/ml$, FNW: $100{\mu}g/ml$, FNW: $500{\mu}g/ml$ FNW-Ag: $10{\mu}g/ml$, FNW: $50{\mu}g/ml$). As a result, there were no differences in normal activity except those exposed to concentrations of FNW-Ag $50{\mu}g/ml$, but there were statistically significant differences in anti-predator response except those exposed to concentrations of FNW $10{\mu}g/ml$. That is, exposed of nanomaterials does not affect ordinary movements, but analyses based on behavioral understandings have shown that it has an influence on the anti-predator response. It is therefore considered necessary to have animal behavioral analysis method performed in the assessment of eco-toxic experiment.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.2
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• pp.105-112
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• 2022

2'-fucosyllactose (2'-FL) is the most abundant human milk oligosaccharide (HMO) present in breast milk, promoting the growth of beneficial microorganisms in the gut and aiding in the relief of allergic and inflammatory reactions. In this study, the anti-melanogenic effects of 2'-FL, and its potential for application in whitening cosmetics, were evaluated. MTT assay was performed on MNT-1 cells, human-derived melanocytes. 2'-FL was treated and replaced at 48 h intervals for 7 days, and it was confirmed that there was no cytotoxicity at 20 g/L or less, while a 40% reduction in melanin production was also observed. Western blot analysis of TYR and TYRP1, factors involved in melanogenesis, revealed that 2'-FL treatment reduced their expression levels. In addition, 2'-FL application and observation of the autophagy marker microtubule-associated protein 1 light chain 3 (LC3) revealed it was converted from LC3-I to LC3-𝚷, indicating increased autophagy. Likewise, confocal microscopy revealed an increase in LC3 puncta after 2'-FL treatment. Therefore, it is suggested that 2'-FL-mediated activation of autophagy reduces melanogenesis by inhibiting the expression levels of TYR and TYRP1 proteins. In conclusion, it has been confirmed that 2'-FL induces autophagy and suppresses melanin production, so its potential as a whitening cosmetic material is expected.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.91-97
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• 2002

This study was conducted to determine the effects of temperature and food onthe nymphal development and adult longevity of the green virid bug, Cyrtorhinus lividipennis Router. Nymphal period was 13.2 to 13.7 days at 24$^{\circ}C$, 10.4 to 10.9 days at 28$^{\circ}C$, and 9.0 to 9.3 days at 32$^{\circ}C$. Number of eggs predated by nymph was 10.6-14.3 at 24$^{\circ}C$, 7.5-9.2 at 28$^{\circ}C$, and 5.8-7.5 at 32$^{\circ}C$. Amount of predation was highest on BPH, followed by SBPH, WBPH, and GLH. Number of nympal moulting was mostly four times (55-75%) followed by three times (25-45%), regardless of temperature and food. Percent emergence rate was 52-70%, 48-66% and 22-38% at 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively, showing a tendency to decrease with increasing temperature, and was affected by foods. Adult longevity, when supplied with one food, was 19.8 to 22.5 days at 24$^{\circ}C$, 15.6 to 17.0 days at 28$^{\circ}C$, and 10.3 to 11.7 days at 32$^{\circ}C$. There was no significant difference among foods in terms of adult longevity, but it tended to be slightly longer when provided with four foods than with one food. Number of eggs predated by an adult, when supplied with one food, was 35.7-54.2, 31.6-44.6 and 18.1-28.2 at 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively. It was highest on BPH, followed by SBPH, WBPH and GLH regardless of temperature. Number of egg Predated by an adult, when supplied with four foods, was 4.0-28.9, 2.9-29.0 and 17-13.6 at 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively, and was significantly different among foods supplied. The results suggest that the significantly different predation amount by adult was due to food preference amoung the different foods.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.358-367
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• 1983

Antibiotic-resistant strains of Salmonella typhimurium and Klebsiella pneumoniae died readily after their addition to raw sewage, but they grew in sterilized sewage. The decline was not a result of antibiotic stresses, and because the bacteria were able to survive in large numbers for at least 15 days in solutions containing no organic nutrients, it was not a result of competition. Toxin production, bacteriophages, and Bdellovibrio did not cause the disappearance of the two bacterial species. A decline was also evident if the sewage was first passed through a $3-{\mu}m$ filter or treated with cycloheximide or cycloheximide plus nystatin, but protozoa developed under these conditions. Little or no decline occurred if the sewage was filtered and treated with the eucaryotic inhibitors before adding S. typhimurium or K. pneumoniae, and protozoa were not detected. S. typhimurium increased in abundance if cycloheximide, streptomycin, and erythromycin or large amounts of glucose were added to sewage. Tetrahymena thermophilus did not significantly reduce the population of S. typhimurium in buffer when the density of the bacterium was about $10^4/ml$. However, when more than $10^8$ Enterobacter agglomerans cells per ml were added to the buffer, T. thermophilus reduced the abundance of E. agglomerans and S. typhimurium to $10^6$ and 10/ml, respectively. The density of S. typhimurium was further decreased by a second increment of E. agglomerans cells. The disappearance of S. typhimurium and K. pneumoniae from sewage thus is the result of predation by protozoa. It is proposed that predators will eliminate a prey species from a natural environment when an alternate prey is present at concentrations above the threshold number for active feeing by the predator and when the rate of growth of the prey is less than the rate of predation.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.05a
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• pp.35-36
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• 2001

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2004.11a
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• pp.49-49
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• 2004

• 한국전자현미경학회:학술대회논문집
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• 1999.05a
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• pp.26-26
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• 1999