• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.625-639
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• 2019

Microplastics are one of the substances threatening the marine ecosystem. Here, we summarize the status of research on the effect of microplastics on marine life and suggest future research directions. Microplastics are synthetic polymeric compounds smaller than 5 mm and these materials released into the environment are not only physically small but do not decompose over time. Thus, they accumulate extensively on land, from the coast to the sea, and from the surface to the deep sea. Microplastic can be ingested and accumulated in marine life. Furthermore, the elution of chemicals added to plastic represents another risk. Microplastics accumulated in the ocean affect the growth, development, behavior, reproduction, and death of marine life. However, the properties of microplastics vary widely in size, material, shape, and other aspects and toxicity tests conducted on several properties of microplastics cannot represent the hazards of all other microplastics. It is necessary to evaluate the risks according to the types of microplastic, but due to their variety and the lack of uniformity in research results, it is difficult to compare and analyze the results of previous studies. Therefore, it is necessary to derive a standard test method to estimate the biological risk from different types of microplastics. In addition, while most of the previous studies were conducted mostly on spheres for the convenience of the experiments, they do not properly reflect the reality that fibers and fragments are the main forms of microplastics in the marine environment and in fish and shellfish. Furthermore, studies have been conducted on additives and POPs (persistent organic pollutants) in plastics, but little is known about their toxic effects on the body. The effects of microplastics on the marine ecosystems and humans could be identified in more detail if standard testing methods are developed, microplastics in the form of fibers and fragments rather than spheres are tested, and additives and POPs are analyzed. These investigations will allow us to identify the impact of microplastics on marine ecosystems and humans in more detail.

• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.27-37
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• 1979

Ninety-five strains of Shigella, 70 of Salmonella paratyphi A, and 230 of Salmonella typhi were tested for their resistance to drugs. Also studied was the inhibition and elimination of drug resistance. All except one strain of Shigella consisted of 79 Sh. flexneri and 16 Sh. sonnei were multiply resistant to chloramphenicol, tetracycline, streptomycin, and splfisomidine. Among them, 70 strains were resistant to ampicillin and carbenicillin, 80 to trimethoprim-sulfamethoxazole, 22 to nalidixic acid, and one to kanamycin, but strain resistant to gentamicin, cephaloridine, and rifampin was not encountered. All strains of S. paratyphi A and S. typhi were susceptible to drugs tested, except sulfisomidine and rifampin, for which all S. paratyphi A were slightly resistant to sulfisomidine and the majority of S. paratyphi A and S. typhi were slightly resistant to rifampin. Approximately 80% of multiply drug-resistant Shigella transferred their resistance to E. coli by conjugation, and the resistance was considered to be mediated by R plasmids. The frequency of transfer of drug resistance varied by donor strains and recipients, but not by selecting drugs. Resistance to nalidixic acid was not transferred by conjugation to the recipients. Drug-resistant Shigella strains successively subcultured in nutrient agar stabs contained clones resistant to drugs and those susceptible to drugs, but the ratio of resistant and susceptible clones varied by strains. The multiply drug-resistant S. typhi and Shigella strains were found to not lose completely their drug resistance by subculture in media. Acriflavine has some effect on the elimination of drug resistance mediated by R plasmids, but the effect varied markedly by strains. Atabrine has no effect among strains tested. The combination of drugs increased the drug actions in majority of cases with synergistic or additive effects.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.2
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• pp.131-136
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• 1985

The calculation of the resulting fluid motion is an important problem of ship hydrodynamics. For a partially immersed body the condition of constant pressure at the free surface can be linearized. The resulting linear boundary-value problem for the velocity potential is the Neumann-Kelvin problem. The two-dimensional Neumann-Kelvin problem is studied for the half-immersed circular cylinder by Ursell. Maruo introduced a slender body approach to simplify the Neumann-Kelvin problem in such a way that the integral equation which determines the singularity distribution over the hull surface can be solved by a marching procedure of step by step integration starting at bow. In the present pater for the two-dimensional Neumann-Kelvin problem, it has been suggested that any solution of the problem must have singularities in the corners between the body surface and free surface. There can be infinitely many solutions depending on the singularities in the coroners.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2000.12a
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• pp.29-34
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• 2000

산업 발달에 따라 날로 많은 식품들이 새롭게 개발되어지고 있다. 또한 이와 병행해서 식품으로 인한 알레르기 발생 빈도도 날로 증가하고 있으며 그 증상 또한 점차 심화되고 있는 것이 세계적인 추세이다. 우리나라도 예외는 아니어서 일반 알레르기 환자뿐 아니라 식품으로 인한 알레르기 환자들이 점차 증가됨이 보고되어지고 있다. 농산물 시장의 수입개방이후 우리나라에는 많은 해외 농산물이 수입되어지고 있으며 그 중 작년 한해의 경우 총 수입 농산물의 10%를 넘는 유전자 재조합 농산물이 우리나라에 수입되어진 것으로 통계 보고되어졌다. 이러한 관점에서 알레르기 환자의 증가와 새로운 식품 (특히 유전자 재조합 식품)의 증가에는 서로 관련성이 있을 것으로 추측되어지고 있어 (새로운) 식품에 대한 알레르기성의 예측과 관리가 필요한 실정이다. 이에 몇몇 발표된 유전자 재조합 식품에 관련된 알레르기성 검사 논문들과 실험실에서 이루어진 연구 결과들을 중심으로 유전자 재조합 식품의 알레르기 위험성에 대해 알아보고자 한다. 일반적으로 식품의 단백질이 알레르겐(allergen)으로 작용하기 위해서는 먼저 소화효소에 의해 분해되어지고 장에서 흡수되어져서 immunopotent cell에 의해 process 되어 immune system에 present 되어져야 한다. 따라서 단백질로 인한 알레르기 반응은 그 단백질의 자연적 형태 뿐만이 아니라 소화 효소에 분해된 단편들의 구조 또는 다른 알레르겐 단백질과의 유사 구조로 인한 교차 반응에 의해 발생함을 기억해야 한다. 식품 단백질 중 어떤 단백질이 알레르겐으로 작용하는가에 대한 특이성 조사에 많은 관심이 집중되어지고 있지만 아직까지는 대략 다섯 개 정도의 일반적인 특성으로서 요약되어질 수 있다. 그러나 이러한 대략의 특성에 적용되지 않는 식품 알레르겐도 많음을 잊어서는 안 될 것이다. 알레르겐으로 작용하는 식품 단백질의 일반적 특성 1. 좋은 수용성 2. 식품내에 많은 부분을 차지하는 주 단백질이 주 알레르겐으로 작용 3. 단백질내에 하나 이상의 IgE-binding site 존재 4. 위장액에 대한 저항성 5. 10～70 kDa 크기 유전자 재조합 기술이란 말 그대로 유전자를 인위적으로 새롭게 조합하는 기술로 이전의 기술로는 불가능했던 유전적 변형을 농작물과 동물에 가능하게 했으며 이로 인해 유전적으로 변형된 식용 동식물의 개발이 가능하게 되었다. 새로운 유전인자를 개체에 삽입함으로 새로운 단백질이 발현 될수 있고 그로 인해 1) 해충과 질병에 대한 저항성 증가, 2) 화학 제초제에 대한 새로운 저항성 부여, 3) 식품의 저장성 향상, 4) 식품의 영향적 보충/향상 등의 이점을 얻을 수 있다 (표 1). 세계적으로 유전자 재조합 된 새로운 농산물의 재배는 날로 증가추세에 있으며 그 중에서 가장 많은 부분을 차지하는 농산물로 soybean을 들 수 있으며 (표 2) soybean을 중심으로 그 알레르기성의 변화가 연구 조사된 몇 가지 예를 살펴보고자 한다. (표 3)에 요약된 soybean중 첫 번째 경우는 재초제에 대한 저항성을 높여주기 위해 Agrobacterium에 존재하는 EPSPS라는 단백질을 콩에서 발현하도록 찬 유전자 재조합 된 콩의 경우이다. 이 콩의 경우에는 첫째. 이전된 새로운 단백질 EPSPS가 다른 여러 식물에 이미 존재하고 있는 단백질로서 우리가 이미 이러한 식품을 섭취할 때 이 단백질도 같이 섭취해오고 있었다는 점, 둘째. 이 단백질이 소화액 분해 실험에서 짧은 시간내에 분해가 되었다는 점, 셋째. 재조합 된 콩과 자연 콩이 성분 분석에서 차이를 나타내지 않았다는 점, 네 번째. 쥐를 통한 다양섭취 실험에서 아무런 이상 반응이 없었다는 점등의 결과를 기준으로 알레르기에 대한 개별 검사 없이 안전한 콩으로 결론짓고 있다. 영양성을 높이기 위해 Brazil nut에서 methionine 함량이 풍부한 2s albumine을 콩에서 발현하도록 한 두 번째 유전자 재조합 콩의 경우 이전된 단백질 때문에 Brazil nut에 알레르기 반응을 일으키는 알레르기 환자들을 조사한 결과 역시 재조합 된 콩에도 알레르기 반응을 일으켰다는 보고이다. Brazil nut에서 콩으로 이전된 단백질이 Brazil nut에서의 알레르기성을 그대로 유지한 점을 볼 때 새로운 단백질이 어디에서 유래하는가가 중요함을 잘 보여준 연구이다 세 번째 콩의 경우 역시 영양성을 높여주기 위해 corn에서 10 kDa과 HSZ 단백질을 콩에서 발현하도록 유전자 재조합했는데 이 콩의 경우는 알레르기 환자들이 유전자 재조합 된 콩과 자연 콩에 반응의 차이를 나타내지 않았다는 결과 보고이다. 위의 세 실험 결과들을 종합해 볼 때 무엇보다도 새롭게 발현된 단백질이 원래 어떤 성질을 갖고 있으며 어디에서 유래했는지가 알레르기성 조사에 중요한 역할을 한다 할 수 있겠다. 또한 유전자 재조합된 식품들은 알레르기 환자들을 위해 표기되어져야 할 것인데 이를 위한 알레르기성 검사 실험은 공공단체를 통해 이루어져야 할 것이며 환자들마다 알레르겐으로 작용하는 단백질의 인식부위(epitope)가 다를 수 있기 때문에 적어도 10명 이상의 알레르기 환자들이 조사되어져서 검사가 이루어져야 할 것이다. 환자들의 혈청을 통한 in vitro 실험에서는 ELISA, RAST, immunoblotting과 같은 검사 방법들이 적용될 수 있고, 그 결과가 음성인 경우에 그 다음 단계로 in vivo 실험에서는 직접 환자의 피부반응검사 (skin prick test)나 DBPCFC (double-blind placebo-controlled food challenge) 검사 방법을 통해 확인되어져서 이 모든 경우가 음성인 경우와 하나라도 양성인 경우를 구별하여 식품에 표기함으로 알레르기 환자들의 유전자 재조합 식품에 대한 안전성이 보장되어져야 할 것이다.

• Journal of fish pathology
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• v.4 no.1
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• pp.1-11
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• 1991

Histopathological changes and methemoglobinemia of the eels (Anguilla japonica) reared at six culture farms in the vicinity of Y$\check{o}$su city were investigated under the conditions of $22.0{\sim}29^{\circ}C$, 4.33~7.33ppm of D.O., pH 6.1~8.2 and 0.03~10.1ppm of nitrite from December, 1989 to June, 1990. All of the eels showed no any abnormal state in action, color and blood, but the eels reared in pH 6.0 had planty of mucus and stickiness on their body surface. Methemoglobin levels were 1.03~9.86% of total erythrocyes in Dec. and 5.05~25.69% in June, and poikilocyte levels were 5.8~30.17% in Dec. and 8.67~74.45% in June. These results indicate the fact that the water management of the culture farms was worse in summer than in winter, even though not good in winter. Hypertrophy was found in the gill, hepatic and kidney tissue of the eels in all the culture farms. In March and June, Fish of all culture farms appeared the detachment of gill lamella epithelium cells, pyknosis and sinusoids of nucleus in the hepatic tissue and hemosiderosis in the kidney tissue. The trend of increase in methemoglobin levels appeared in the fish of culture farms with high nitrite concentration, which didn't appear equally in all the culture farms. However, in the culture farms of pH 6.0, methemoglobin and poikilocyte levels were increased independently of concentration of nitrite, and degeneration in the tissue of the gill, liver and kidney was also appeared.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.439-446
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• 2005

Ferritin is known to be the principle iron-storage protein in a wide variety of rganisms. The electro­phoretic mobility and immunological cross-reactivity of dog splenic ferritin were compared with those of horse, bovine, and pig splenic ferritin after isolation using heat treatment, salting out, column chromatography, and ultrafiltration. These isolation methods allowed the recovery of $\~84{\mu}g$ of the ferritin per g of spleen. The iron content in the dog ferritin was $22.7\%$, which appeared to be higher than those in the other mammalian ferritins tested. The electrophoretic mobility of the dog ferritin under nondenaturing conditions was similar to its bovine counterpart, whereas it was more identical to pig and horse ferritins on an SDS-polyacrylamide gel. The molecular weight of the dog ferritin subunit was 19.5 kDa on an SDS-polyacrylarnide gel, and the subunit was unable to bind with iron. The polyclonal anti-dog ferritin raised in rats was able to cross-react with the pig, bovine, and horse ferritins, upon Ouchterlony double immunodiffusiion. A Western blot analysis also revealed that the anti-dog ferritin, which specifically bound with the dog ferritin subunit, could also recognize the horse, bovine, and pig ferritin subunits and the maximum cross-reactivity was exhibited with the pig ferritin subunit, indicating that the dog ferritin is immunochemically more similar to the pig ferritin than its other mammalian counterparts. Accordingly, these results elucidate the biochemical and immunochemical characteristics of dog ferritin that might have a potential to be applied as an oral iron supplement to treat iron deficiency anemia.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.370-378
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• 1983

Changes of protein and amino acids composition in improvement-Meju inoculated with Aspergillus oryzae were emamined at various time intervals over 6-day test period. To investigate those changes systematically, Disc gel electrophoresis, gel fiteration and amino acid analyzer were used. Following results were obtained; 1. Nitrogen solubility of the soybean meal in $Na_{2}SO_{4},\;MgSO_{4},\;Na_{2}CO_{3},\;NaCl\;and\;Na_{2}HPO_{4}$ solutions of various concetrations were determinated. The salt soluble protein of soybean meal was highly dispersible on 0.4M $Na_{2}SO_{4}$ solution and the extractability of protein was 33%. 2. From the quantitative fractionation of soybean proteins, albumin content (46.0%) was highest followed by globulin (33.9%), glutelin (19.5%) and prolamin (2.4%). During Meju incubation period, albumin and prolamin increased gradually but glutelin decreased. Globulin content was not changed substantially. 3. When albumin was fractionated by Sephadex G-200, the following results were obtained. Soybean albumin showed fraction which was reduced to 3 fraction at 0-day of incubation. The number of fraction, however increased to 8 after 6-day of incubation. 4. Amino acids of albumin in soybean and Meju appeared to be 17 kinds. Glutamic acid and aspartic acid were the highest. In amino acid composition of cooked soybean albumin, arginine, aspartic acid, glutamic acid and glycine remained higher than those of Meju throughout incubation period. 5. The major fraction of albumins from soybean and Meju fractionated by Sephadex G-200 showed 17 kinds of amino acid. Aspartic acid and glutamic acid were the highest. During Meju incubation period, the change of amino acid composition was investigated; threonine, serine, lysine, histidine, alanine, isoleucine, leucine, phenylalanine and $NH_3$ was increased gradually, the others decreased. 6. According to the electrophoretic pattern, soybean protein showed 13 bands which decreased to 3-after cooking. During incubation, those bands increased gradually to 10 bands after 6-days.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.347-358
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• 2004

In Mongolia which consists of nomadic populations, horse has been loved by nomads and considered most important transportation means. Horses have been used when they were making long journey looking for new plain ground for grazing. Therefore, horse is closely connected with Mongolian nomadic culture. In Korea, too, horses had been considered one of most important means for transportation and military. The symbolism of horse that is represented in both Mongolia and Korea is Heavenly Horse which communicates with the God and it was sanctified as a Sacrificing Horse which was sent to God for sacrifice, and it was even worshiped as Divine Horse, the diety. As is the case of two of Mongolian customs associated with Mongolian language are 'the ceremony of horse's giving birth her young' and 'the ceremony of letting the mare go where it was before', all the cases are related with cattle's milk. The ceremony of 'horse's giving birth her young' is the ceremony where people hope that they would see the young can grow well which were born in early summer thus increasing the numbers of horse. To go with this, they perform a ceremony of Chachal in which they sprinkle the best quality white milk which is the symbol of good luck and hope they would produce plentiful of dairy products. The ceremony of 'letting the mare go where it was before' is also the ceremony where people hope to have many new born young horses thus produce more dairy products and Airag for the next year as milking is no more available for that you. Since the unified Silla Era, Koreans have performed a sacrifice rituals to horse in auspicious day. It's purpose is to see their horses get no disease and bear as many youngs as possible. The Back Ins Je, one of well blown festivals in Jeju Island, was originated from people's wish to prosper in stock farming. It can be said that the custom of Korea and Mongolia related with horse's giving birth was originated from the wishes to god for fertility and fecundity. On top of that, while Mongolians sprinkled horse's milk both on the ground and to the air hoping they would have increased houses and, thus, secure many dairy products, Koreans wish that they would see the increased number of horses and their healthy conditions through heavenly rituals.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.1
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• pp.67-76
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• 2000

An experiment was conducted to evaluate the effects of lime, zeolite, and rock phosphate as coating materials and coated seed size on germination, establishment, and early growth of pasture species at the experimental livestock farm, Yonam College of Agriculture in 1997. Germinating energy and germination of coated tall fescue and orchardgrass seeds were lower than those of non-coated seeds. Coated seed of tall fescue with 70% lime and 15% rock phosphate was the best in germination. The germination of small size seed (< ${\varnothing}2$ mm) was better than those of medium (> ${\varnothing}2$ mm and < ${\varnothing}2$ mm) and large size seeds (> ${\varnothing}2$ mm). Germination of coated orchardgrass seed with 55% lime and 30% rock phosphate treatment was higher than that of other coated seeds, and germination of small size seed was higher than those of medium and large size seeds (p<0.05). Germination energy and germination of coated alfalfa and birdsfoot trefoil seeds were lower than those of non-coated seeds. Germination of coated alfalfa seed with 70% lime and 15% rock phosphate, and 45% lime and 55% rock phosphate was higher compared with other coated seeds. Germination of medium size seed was higher than those of small and large size seeds (p<0.05). Among coated birdsfoot trefoil seed, 45% lime and 40% rock phosphate treatment resulted in higher germinating energy and germination than other treatments. There was no significant difference in establishment and early growth of coated tall fescue and orchardgrass seeds. However, tall fescue and orchardgrass coated with 45 % lime and 40% phosphate rock showed higher establishment and early growth. There was also no significant difference in establishment and early growth of coated alfalfa among the treatments. Among coated treatments, establishment and early growth of alfalfa coated with 75% lime and 10% rock phosphate were the highest and showed 46.4% and $72.6\;g/\textrm{m}^2$, respectively. Establishment and early growth of coated birdsfoot trefoil with 55% lime and 30% rock phosphate were the highest among coated birdsfoot trefoil seed (p<0.05) and recorded 46.4% and $44.6\;g/\textrm{m}^2$, respectively. Results of this study indicate that the germination of coated grass and legume seed may be improved by increasing the percentage of rock phosphate and decreasing that of lime. With regard to seed size, the germination of pasture species with small seed size (< ${\varnothing}2$ mm) may be better than medium and large size seeds except alfalfa. Establishment and early growth of grasses can be also improved by increasing the percentage of rock phosphate and decreasing that of lime.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.131-137
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• 1986

Korean lawn, Zoysia japonica STEUD, is the type of a perennial warm-season lawn grass that has a naturally green period during 5 months from May to September. This study was carried out to detect the effects of N-P-K fertilization, regrowth capacity after mowing and chlorophyll contents on prolongation of the green period in Zoysia japonica grasslands. The results obtained are summarized as follows: 1. The effects of nitrogen fertilizer application on Zoysia japonica grasslands were affected on regrowth capacity after mowing, green color of leaf canopies and chlorophyll contents, respectively. 2. A the experimental plots which applied 45g/$m^2$/10 weeks of $N_3$ fertilizer, there were high significant effects on prolongation of the green period and the plots of phosphorus and potassium had additive effects. 3. Prolongation of the green period to the last ten days of October was obviously possible by slow degrees in proportion to increment of N-P-K fertilization. 4. However, it is interpreted that more prolongation of the green period is impossible with N-P-K fertilization and irrigation treatments, unless the intermediate turfgrasses between $C_3$ and $C_4$ plants must be found and bred.