• 한국어병학회지
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• 제5권2호
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• pp.93-118
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• 1992

담수어류중의 주요 양식대상종인 참장어(뱀장어), Anguilla japonica TEMMINCK et SCHLEGEL의 아질산 독성에 의한 만성적인 중독증을 조사한 결과를 요약하면 다음과 같다. 1. pH 5.5와 6.0에서는 6주째부터 아질산의 농도에 관계없이 참장어 복면에 회색반문이 생겼다. pH 5.5에서는 시일이 경과함에 따라 점액물질이 많이 분비되어 백탁되면서 참장어는 죽기 시작했다. 2. 아질산 10ppm구에서 8주간 사육하였을 때 혈액이 갈색으로 변하였고, 아질산 30ppm구에서 8주간 사육하였 때 빈혈증상이 나타났다. 3. 아질산의 농도가 높을 수록, pH가 낮을 수록 아가미 상피세포 조직의 표면에 점액물질의 분비가 많아졌다. 4. 아질산의 농도가 높아짐에 따라 염세포의 수가 감소되었으며, 아질산 40ppm구에서는 새변의 선단 부위에서만 염세포가 관찰되었다. 5. 아질산의 농도가 10ppm 이상인 경우 새변의 퇴행성 변성이 진행되어 상피세포의 박리와 탈락이 일어나며 2차새변의 모세혈관이 위축되고 붕괴되었으며 또한 만곡증상도 많이 나타났다. 6. 수온과 아질산의 농도가 높을수록 새변에 혈전이 많이 생기며 괴사되는 부분도 많이 관찰되었다. 새변의 병변이 적게 일어난 것은 아질산 농도가 10ppm 이하일 때 였으며 아질산 농도 1ppm과 5ppm에서도 새변의 병변은 관찰되었으나 시일이 지남에 따라 정상적인 새변으로 재생되는 경향이 있었다. 7. 참장어의 아질산에 대한 성장저해 농도는 혈전의 형성이 비교적 적은 pH 7.0~7.5에서의 아질산 농도가 5ppm 보다는 높고 10ppm보다는 낮은 농도일 것이고, 아질산에 대한 안전농도는 2차새변의 박리와 혈전이 생기지 않고 모세혈관벽의 붕괴로 출혈이 일어나지 않으며 염세포가 새변의 기저부에까지 출현하는 pH 7.0과 7.5의 아질산 농도가 1ppm보다는 낮은 농도일 것으로 보인다.

• 한국농림기상학회지
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• 제1권2호
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• pp.127-134
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• 1999

본 연구는 중부지방에 많이 분포하고 있는 소나무-굴참나무 혼효림과 각각의 단순림을 대상으로 사면별(북, 서, 남) 입지조건에 따른 임분 통계량과 천연갱신에 대한 광 조건을 비교 분석하여 합리적인 조림 무육 방안을 제시하기 위한 기초 자료를 얻고자 수행되었다. 조사지의 소나무-굴참나무 혼효림과 각각의 단순림을 대상으로 남경사면, 북경사면 그리고 서경사면별로 입지와 생육분포를 고려하여 표본점을 설정하였으며, 표본점의 형태는 원형으로 하였으며, 표본점내에 평균 30~40본이 포함되도록 표본점의 크기를 0.05 ha(반경 12.62 m)로 하였다. 표본점의 수는 사면별로 상 . 중 . 하부를 구분하여 소나무 단순림 9개, 소나무-굴참나무 혼효림 8개, 참나무 단순림 6개로 총 23개를 조사하였다. 또한 임분내 광 조건은 어안(fish-eye)lens(180$^{\circ}$)를 이용한 crown-photo 방법과 PAR-sensor를 이용하여 각 Plot에 대한 나지와의 비교를 통하여 임분내 상대광도를 측정하였다. 소나무 단순림의 울폐도(75.5%)는 혼효림(90.9%)과 굴참나무 단순림(93%)보다 훨씬 적게 나타났으며, 임분내 상대광도는 이와 반대의 경향을 나타냈다. 또한 혼효림에 있어서 울폐도는 북사면에서 남사면으로 가면서 점차 감소하는 경향과 이와 반대로 임분내 상대광도는 증가하는 경향을 나타냈다. 임분내 상대광도와 임분 prameter와의 관계를 분석한 결과, 단면적과 N/ha의 증가에 따라 임분내 상대광도는 감소하는 경향을 나타냈다. 굴참나무의 천연갱신 수는 임분내 상대광도의 증가에 따라 함께 증가하는 직선회귀 관계에 놓여 있었으며, 특히 남향의 혼효림에서 굴참나무의 천연갱신이 가장 높았다. 그러나 소나무의 천연갱신은 전혀 발견하지 못했으며, 이는 임분 내 상대광도가 4~8%로 매우 낮고, 낙엽충의 깊이가 10 cm 이상으로 두껍기 때문에 종자가 발아 할 수 없는 것으로 사료된다. 따라서 소나무 천연갱신의 결정적 인자로는 임분 내의 광 조건과 낙엽 . 부식충의 두께가 결정적인 요소로 판단된다.

• 한국양식학회지
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• 제19권3호
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• pp.210-215
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• 2006

수온과 광주기에 따른 볼락 치어의 대사율 변화를 조사하기 위해 평균 무게 $20.5{\pm}0.7g$을 대상으로 수온(10, 15, 20, $25^{\circ}C$)과 광주기(24L:0D, 12L:12D, 0L:24D)에 따른 산소 소비율은 측정하였다. 12가지 실험 조합의 산소 소비율은 유수식 형태의 호흡실을 이용하여 24시간 동안, 3반복 측정하였다. 수온과 광주기 그리고 두 인자의 상호작용 모두가 볼락 치어의 산소 소비율에 유의한 영향을 미쳤다(P<0.001). 각 광주기 조건에서 수온 상승에 따라 산소 소비율은 유의적으로 증가하였다(P<0.01). 10, 15, 20 그리고 $25^{\circ}C$에서의 시간당 평균 산소 소비율은 각각 $178.3\sim283.5,\;386.7\sim530.7,\;529.2\sim754.3$ 그리고 $590.0\sim785.5mg\;O_2kg^{-1}h^{-1}$였으며, $Q_{10}$ 값은 $10\sim15,\;15\sim20,\;25\sim25^{\circ}C$에서 각각 $3.17\sim5.51,\;1.87\sim2.10,\;1.08\sim1.24$이었다. 연속 명기(24L:0D)에서의 산소 소비율은 연속 암기(0L:24D)에서보다 유의하게 높았다(P<0.05). $10^{\circ}C$를 제외한 모든 수온 조건에서 12L:12D에서 가장 높은 산소 소비율을 보였으며, 24L:0D의 명기에서의 산소 소비율은 같은 조건의 암기 때보다 유의하게 높은 산소 소비율을 보였다(P<0.05). 이 실험 결과는 각 수온과 광주기 조건에서의 볼락 치어의 산소 소비율을 파악할 수 있으며, 사육관리 및 생리적 반응 정량화를 위한 생체역학 모델 결정에 활용할 수 있다.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.130-138
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• 2016

The use of antibiotics in aquaculture raises environmental and food safety concerns because chronic exposure of an aquatic ecosystem to antibiotics can result in the spread of antibiotic resistance, bioaccumulation of antibiotics in the organisms, and transfer of antibiotics to humans. In an attempt to overcome these problems, high-concentration red clay was applied as an alternative antibiotic against the following common fish pathogens: Aeromonas salmonicida, Vibrio alginolyticus, and Streptococcus equinus. The growth of A. salmonicida and V. alginolyticus was retarded by red clay, whereas that of S. equinus was promoted. Phase contrast and scanning electron microscopy analyses confirmed the attachment of red clay on cell surfaces, resulting in rapid gravitational removal and cell surface damage in both A. salmonicida and V. alginolyticus, but not in S. equinus. Different cell wall properties of grampositive species may explain the unharmed cell surface of S. equinus. Significant levels of oxidative stress were generated in only the former two species, whereas significant changes in membrane permeability were found only in S. equinus, probably because of its physiological adaptation. The bacterial communities in water samples from Oncorhynchus mykiss aquacultures supplemented with red clay showed similar structure and diversity as those from oxytetracycline-treated water. Taken together, the antibiotic effects of high concentrations of red clay in aquaculture can be attributed to gravitational removal, cell surface damage, and oxidative stress production, and suggest that red clay may be used as an alternative for antibiotics in aquaculture.

• 수산경영론집
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• 제15권1호
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• pp.1-57
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• 1984

The fisherman has been playing the roles of forming the fisheries village and surviving the fisheries production. Therefore, we should understand the nature of the fisherman's successor-cultivation which has been performed in order to maintain equlibrium between the fisheries economy and the national economy. Thesedays, fisherman's successor-cultivation mainly has been undertaken by the government in order to facilitate forming the economic foundation of fisherman's successor who has intended to choose "fisheries" as his own occupation in the future. From the above-mentioned, we find the meaning of the undertaking as both securing the foundation of living permanently and having the worth-while life of a professional fisherman by the survival and growth of his own business. And then, choosing the "fisheries" as an occupation, the successor should be satisfied with the requisites of occupation: 1) maintaining one's living, 2) working out one's individuality, 3) fulfilling one's social role-through engaging in the fisheries. Therefore, in order to have these requisites satisfied, I intend to suggest the followings : Firstly to maintain one's living, the environment of fisheies village should be kept in good condition to facilitate the successor's economic performance. Secondly to work out one's individuality, the fisheries' educational system should be adjusted to improve fisherman's ability. 1 hope to institute "the course of regional fisheries management" in fisheries high school and junior vocational collage, and "the school of fisheries management" for the learning of advanced fisheries knowledge. Thirdly to fulfill one's role, the opportunity actively participating in decision-making of the village's affair should be prepared more sufficiently, and the present fishing-centered fisheries system should be reformed into the fish-farming-centered fisheries system. To do this, the long-perspective vision is necessary. These three suggestions are come out from the macro-view point. Meanwhile the fisherman as an individual to improve his business is from the micro-view point. That is, the public aid, financial and legal, should be prepared. The above-mentioned suggestions are necessary to equalize fisherman's social status with other professional's especially from the result of improving the successor's economic force. Therefore, the principle of cultivating the fisherman's successor should be the principle of social equilibrium. be the principle of social equilibrium.

• 수산해양교육연구
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• 제27권5호
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• pp.1491-1498
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• 2015

In this study we investigated the effect of vaccine efficacy and immune activities by feeding additives several natural herbal remedies extracts of Sweet Wormwood (Artemisia annua), Galla Rhois, Oriental raisin tree (Havenia Dulicis) and 6-mixed herb to Oilve flounder, Paralichthys olivaceus. Each group of fish fed with the herbal remedies added feed and basic formula during the seven weeks and vaccinated with Edwardsiella tarda Formalin killed vaccine after 4 weeks feeding. Relative Percentage Survival values (RPS) in the group was assessed by the challenge with E.tarda. All groups with the herbal remedies added feed enhanced growth rate, but there were not significantly different in lysozyme activity and agglutination titer. In a challenge experiment with E.tarda, RPS in the all groups feeding additives natural herbal remedies was higher than that of the control group. These results suggest that the natural herbal remedies extracts of Sweet Wormwood (Artemisia annua), Galla Rhois, Oriental raisin tree (Havenia Dulicis) and 6-mixed herb would be effective to enhance efficacy of vaccination to Olive flounder.

• 동아시아식생활학회지
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• 제7권4호
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• pp.502-511
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• 1997

This study was to Investigate the consumer's understanding and purchasing foods, which were produced by organic agricultured method. The results of this study were as follows: 1. When shopping foods, the items which were deeply considered were taste of family and food safety. 2 Contaminants which were considered to be dangerous were, in decreasing order, agricultural chemical residue, food additives, environmental contaminant, and microbial hazard. Consumer's perception to agricultural chemical residue In foods was 'be much serious' and over 4.0 by Likert 5 scale. 3. Among of characteristics which was associated with organic farmming foods, taste and nutrition were considered the least important characteristic, whereas safety and good health were considered the most important characteristic. 4. The foods which were thought to be polluted by agricultural chemical residue were, in decreasing order fruit, vegetable, cereal, egg, meat, milk, and fish & shellfish. 5. The respondants' purchasing degree for organic farmming foods was 'often purchase' and 3.44 by Likert 5 scale. These result showed significant difference for age(p＜0.05), for education level (p＜0.05), for income(p＜0.05) and for food expenditure(p＜0.05), respectively 6. The type of organic farmming food which frequently purchased were, in decreasing order, vegetable. fruit, egg, cereal, milk, and meat. The reasons why consumer purchased organic farmming food were, in decreasing order, no pesticide/therbicides, no artifical fertilizer, no growth regulators, residue free, and good quality. 7. 78% of respondants Indicated that they bought organic farmming food in this year increasely or same as last year and 91.9% of respondants Indicated that they plan to buy organic farmming foods in next year.

• Applied Biological Chemistry
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• 제27권
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• pp.56-67
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• 1984

As in many other country, the use of organic matter in Korea has long history. Farmers understand the value of organic matter as the source of plant nutrient and soil improving agent in general. Since 50 years ago, the sources of organic matter in paddy soils were compost, rice and barly straw, green manure, animal waste, fish and beancake, etc.. Application of green manures such as vetch and chinese milk vetch showed no significant effect on the yield of brown rice in paddy soil. On the other hand, the effects of compost and rice straw showed more significant on the yield of brown rice in paddy soil. Application of rice straw in rice cultivation is commonly made at different times between harvest, early spring and several weeks before transplanting. Considering the suitable paddy soil for application of rice straw under well to moderately well drained soil, the yield was pronounced more than poorly drained soil. Based on laboratory and field experimants, application of rice straw promoted the decrease of oxidation-reduction potential in well to moderately well drained soil. This results to be enhanced the release of some mineral nutrients,. such as potassium, calcium, silicon, and increase of availability of soil phosphorus. In the field experiments, results obtained from nitrogen fraction on the immobilization-mineralization of the tracer nitrogen applied in paddy soil,the amount and index of organic nitrogen incoporated in soil was more pronounced in rice straw application than control. Rice straw and its transformation products incoporated in the soil, provided the inflow of energy necessary to maintain heterotrophic microbes activities. Rice straw and its transformation products, especially soluble carbohydrate, enhanced the population of free-living heterotrophic $N_2$ - fixing microbes. Moreover, rice straw and its transformation products in paddy soil, enhanced the activities of soil enzymes such as dehydrogenase and urease.

• Ocean and Polar Research
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• 제33권2호
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• pp.159-169
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• 2011

Antifreeze proteins (AFPs) have ice binding affinity, depress freezing temperature and inhibit ice recystallization which protect cellular membranes in polar organisms. Recent structural studies of antifreeze proteins have significantly expanded our understanding of the structure-function relationship and ice crystal growth inhibition. Although AFPs (Type I-IV AFP from fish, insect AFP and Plant AFP) have completely different fold and no sequence homology, they share a common feature of their surface area for ice binding property. The conserved ice-binding sites are relatively flat and hydrophobic. For example, Type I AFP has an amphipathic, single ${\alpha}$-helix and has regularly spaced Thr-Ala residues which make direct interaction with oxygen atoms of ice crystals. Unlike Type I AFP, Type II and III AFP are compact globular proteins that contain a flat ice-binding patch on the surface. Type II and Type III AFP show a remarkable structural similarity with the sugar binding lectin protein and C-terminal domain of sialic acid synthase, respectively. Type IV is assumed to form a four-helix bundle which has sequence similarity with apolipoprotein. The results of our modeling suggest an ice-binding induced structural change of Type IV AFP. Insect AFP has ${\beta}$-helical structure with a regular array of Thr-X-Thr motif. Threonine residues of each Thr-X-Thr motif fit well into the ice crystal lattice and provide a good surface-surface complementarity. This review focuses on the structural characteristics and details of the ice-binding mechanism of antifreeze proteins.

• 한국발생생물학회지:발생과생식
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• 제14권1호
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• pp.21-25
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• 2010

Nile tilapia (Oreochromis niloticus) are mouth-brooders so that the females holding eggs in their mouth sacrifice their somatic growth for reproduction. For this reason, artificial control of reproduction for the culture of this species has been of interest. Manipulation of photoperiod is an emerging technique for such purpose, but little information is available to establish appropriate photoperiod regime. To obtain necessary basic information, sexually mature females were individually accommodated to glass aquarium, and the spawning activity of these females were monitored for two years under natural photoperiod regime. Female tilapia spawned most frequently on March, April and May when the day length gradually increased from 11 hours to 14 hours and least frequently on September, October, November and December when the day length gradually decreased from 13 hours to less than 10 hours in the first year. The decrease of spawning frequency as day length decreased was also observed in the second year, although the increase of spawning frequency as day length increased was less clear. Spawning of female tilapia was less active when the night was dark due to the disappearance of moonlight (Dark Phase), compared to the Phase of Getting Lighter, Light Phase and Phase of Getting Darker. Results from this study suggest that long day length, particularly increasing phase, is favoured for active spawning of Nile tilapia, and that this species, as a tropical fish species, may utilize changing lunar phases as a secondary environmental cue for reproduction.