• 대한미생물학회지
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• 제17권1호
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• pp.35-41
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• 1982

Enterotoxigenk E. coli is one of the major causative agents of the infantile diarrhea and traveler's diarrhea. The heat-labile enterotoxin is thought to be a virulence factor in the pathogenesis of the diarrhea and to be a marker for identification of the enterotoxigenic E. coli from non pathogenic E. coli. Therefore knowledge about the heat-labile enterotoxin is essential not only for understanding the pathogenesis but also for the diagnosis of the diarrhea. However the in-vitro heat-labile enterotoxin production is reported to be greatly affected by the cultural condition. In this regards, this study was designed to know the optimal conditions for the production of the heat-labile enterotoxin by assaying the permeability factor in the 18 hours culture supernatant of E. coli 08K25(B2) H9 and of E. coli 015 H11. Results obtained were summerized as follows: 1. Amounts of heat-labile enterotoxin produced were greater at initial pH 8.5 than at 7.0 of CYES-2 broth culture. However, the bacterial growth itself was more abundant at 7.0 than at 8.5. 2. Heat-labile enterotoxin per unit volume of culture supernatant was greater at shaking culture than at standing culture condition, but ratio of the enterotoxin produced over the unit mass of E. coli calculated was greater at standing culture than shaking culture condition, indicating that the greater yields of the toxin produced at shaking culture was due to increase in E. coli cell mass compared to the standing culture condition: 3. The enterotoxin produced in the lincomycin(128 microgram/ml) supplemented media was 5 or 11 times greater on the basis of enterotoxin per unit mass of E. coli, compared to the lincomycin-non-supplemented media, indicating that lincomycin itself increases the enterotoxin production. 4. Treatment of 18 hours culture of E. coli with polymyxin B(0.2 mg/ml) for 1 hour increased the yields of enterotoxin amounting to 2 or 5 times of the non-treated control cultures.

• 한국가금학회지
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• 제42권1호
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• pp.87-100
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• 2015

It is well known that dietary protein affects the growth performance and carcass composition of poultry. Over the last several decades, numerous studies have been carried out to investigate to optimize the level of dietary protein since the protein is an important and expensive constituent in poultry feed. It is generally accepted that dietary protein should represent a balance of amino acids supporting the requirements for growth and maintenance of birds. A protein with balanced essential amino acids that matches a bird's requirement and sufficient non-essential amino acid nitrogen to enable the synthesis of all of the non-essential amino acids, is referred to as an 'ideal protein'. Feeding of excess protein or amino acids may result in an amount of nitrogen emission. Most common method to reduce nitrogen emission is using diet formulation which has lower dietary crude protein level and higher concentration of amino acid supplements. However, there are conflicting reports whether low protein diets supplemented with synthetic amino acids can obtain the growth performance equal to high protein diets. Excessive nitrogen excretion caused by amino acid imbalance also may influence the environment of poultry house due to ammonia production from uric acid. These environmental conditions may increase the incidence of skin problem or respiratory diseases of chickens. Various strategies based on comprehensive understanding should be tested to optimize nitrogen utilization and reduce nitrogen emission while maintaining the performance in poultry production.

• Mycobiology
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• 제31권1호
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• pp.46-49
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• 2003

A method of spawn making procedures through the application of fermented sawdust for the purpose of avoiding contamination by undesirable fungi in the course of Pleurotus ostreatus mycelial growth was evaluated. Of three kinds of supplements, rice bran was the most effective to raise temperature up to $70^{\circ}C$. Mycelial activity and density was more considerably improved in the case of using fermented sawdust supplemented with rice bran than the case of non-fermented sawdust. Primordia of Pleurotus ostreatus were formed on fermented sawdust. The substrate of fermented sawdust showed potential to prevent the growth of Trichoderma sp. which caused a symptom on mushroom mycelium, whereas there was nothing to inhibit the growth of Trichoderma sp. during 30 days after inoculation in non-fermented sawdust.

• Asian-Australasian Journal of Animal Sciences
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• 제14권1호
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• pp.54-60
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• 2001

A study was conducted to assess the nutritive value of two diets based on a low-energy variety of wheat, RAC C1 and their effects on intestinal mucosal structure and function in broiler chickens. The diets were fed with or without microbial enzyme supplement to male and female broiler chickens. The digesta viscosity was reduced (p<0.001) through supplementation with a microbial enzyme in male and female chicks. Enzyme supplementation also improved the dietary apparent metabolizable energy content (p<0.001) and had slight but non-significant positive effects on chick growth and feed conversion ratio. Intestinal mucosal structure and enzyme function were not affected by microbial enzyme supplement. Male chicks consumed more feeds (p<0.001), attained higher final body weight (p<0.001) and were more efficient at feed utilization (p<0.01) than the female chicks. Except for duodenal villus surface area and ileal protein content, intestinal mucosal structure and enzyme activities were similar between the two sexes and dietary treatment groups. The study showed an improvement in the nutritive value of the diets in the presence of the microbial enzyme supplement.

• Journal of Ginseng Research
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• 제9권1호
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• pp.24-35
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• 1985

Rusty root of ginseng has been known as one of the limiting factors in ginseng production in Korea. An attempt was, therefore, made to elucidate biological and chemical natures of the rusty root, and the redox Potential of the ginseng cultivated soils were measured and compared with diseased and non-diseased soils. Reddish discoloration was most frequently observed on the epidermis of ginseng root and the pigments were accumulated in all epidermal cells of the diseased lesions. The lower the redox potential of the ginseng cultivated soil was, the more severe the rusty root was observed. Fe content in the diseased epidermis was 3 times higher than that of healthy one. Organic acids such as oxalic, malonic, succinic, and citric acids were also higher in the mss root than in the healthy one. Thin layer chromatogram of phenolic acid fractions obtained from the epidermal cells of the rusty root of ginseng exhibited 3 to 4 unidentified substances not found in the healthy root. Also lignification of the epidermal cells and the activity of phenylalanine ammonia lyase were greater in the rusty root than the healthy root. Colony formation and conidia production of F. solani, And mycelial growth and sclerotium formation of Sclerotinia sp. isolated from ginseng root were suppressed in a nutritionally minimal medium supplemented with water extract of rusty ginseng root epidermis. It is, therefore, suggested that rusty root of ginseng is caused by unfavorable rhizosphere environmental stress or stresses resulting abnormal metabolism in the root as a selfdefence mechanism of non-specific resistance responses.

• 한국컴퓨터정보학회논문지
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• 제15권2호
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• pp.83-89
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• 2010

본 논문에서는 게임이 아동들이나 청소년들에게 폭력성을 배제하고 교육적인 내용의 게임을 만들려면 게임의 구성과 설계가 중요하다. 그러므로 본 논문에서는 아동이나 청소년들에게 교육적인 내용의 게임을 설계하여 두뇌 발달을 시키고, 게임의 즐거움을 줄 수 있도록 하였다. 특히 아동들을 위해 화면에서 토끼 같은 캐릭터를 추가하여 게임의 폭력성 보다는 친근한 이미지의 동물들의 캐릭터를 살려 설계하였다. 전체 화면에 대한 객체 설계와 구현된 게임에 대한 화면에 대한 내용도 살펴보았으며, 구현된 게임의 장점을 나열하였고, 향후 발전방향에 대하여 논하였다.

• 한국식품영양과학회지
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• 제28권3호
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• pp.670-676
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• 1999

The effect of exercise and/or high fat diet on carnitine status and carnitine palmitoyltransferase I(CPT I) level were investigated in Weanling Sprague Dawley rats. The rats were fed an AIN 76 diet or a modified high fat AIN diet, supplemented with 35% corn oil, for 31 days. During the 31 day period half of the animals in each dietary group were exercised on a treadmill for 90 minutes per day. Carnitine concentrations were determined in plasma and liver and CPT I mRNA levels were measured by Northern blot analysis with CPT I cDNA probe in livers of rats. Exercise rats gained less weight than non exercised rats during the study for high fat diet group. Exercise rats had a higher plasma acid soluble acylcarnitine and acid insoluble acylcarnitine concnetrations than non exercised rats for normal diet group. Exercise or high fat diet increased liver carnitine concentration, but a mixed effect was not shown. In exercised rats, CPT I mRNA levels increased significantly relative to those of nonexercised rats. CPT I mRNA levels also increased when compared high fat fed rats with those of normal diet fed rats. These data suggest that there is a correlation between carnitine concen trations and CPT I mRNA levels and that CPT I can be regulated at the transcriptional level by exercise and/or high fat diet.

• 한국어교육
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• 제29권1호
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• pp.85-108
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• 2018

This study pointed out the reality that many novice Korean language teachers who lack rater training are scoring the learners' writing skill. The study performed and analyzed a case where pre-service teachers were educated in order to explore the possibility of promoting rater training in a Korean language teacher training course. The pre-service teachers majoring in Korean language education at the graduate school scored TOPIK compositions and were provided feedback by the FACETS program, which were further discussed at the rater meeting. In three scoring processes, the raters scored with conscious of own rating patterns and showed positive change or over correction due to excessive consciousness. Consequentially, ongoing training can improve rating ability, and considering the fact that professional rater training is hard to progress, the method composed of FACETS analysis and rater training revealed positive effects. On the other hand, the rater training including native Korean and non-native(Chinese) speakers together showed no significant difference by mother tongue but by individual difference. This can be interpreted as a positive implication to the rating reliability of non-native speakers possessing advanced Korean language abilities. However, this must be supplemented through extended research.

• ALGAE
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• 제34권2호
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• pp.91-97
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• 2019

Chilean species of marine macroalgae with amphitropical distributions oftentimes result from introductions out of the Northern Hemisphere. This possibility was investigated using haplotype data in an amphitropical red macroalgae present in Chile, Callophyllis variegata. Published sequence records from Canada and the United States were supplemented with new collections from Chile (April 2014-November 2015). Specimens of C. variegata were amplified for the 5′ end of the cytochrome c oxidase subunit I gene (COI-5P) and the full length nuclear internal transcribed spacer region. Haplotype networks and biogeographic distributions were used to infer whether C. variegata was introduced between hemispheres, and several population parameters were estimated using IMa2 analyses. C. variegata displayed a natural amphitropical distribution, with an isolation time of approximately 938 ka between hemispheres. It is hypothesized that contemporary populations of C. variegata were established from a refugial population during the late Pleistocene, and may have crossed the tropics via rafting on buoyant species of kelp or along deep-water refugia coincident with global cooling, representing a rare case of a non-human mediated amphitropical distribution.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.37-37
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• 2019

Cryopreservation is one of the ideal and suitable methods for long-term storage of plant germplasm. The plant contaminated with diseases and pathogens are decreased the multiplication rate, survival rate and high quality of plants after cryopreservation. The aim of this work was to improve a micropropagation method for lily in Korea, which are cultivars and indigenous plant. In the last process of rinsing scales after surface-sterilization, we tried to control the diseases and pathogens lived within the tissue by rinsing in 0.03% sodium hypochlorite (NaClO) instead of sterile distilled water. Bulb scales of Lilium were cultured in vitro on MS medium supplemented with Plant Preservative Mixture (PPM). The newly small bulb formed from bulb-scales was transferred to MS medium. We checked the non-contamination and survival rate after 2 weeks in culture. Non-contamination was shown to be 70 to 90% in formed small bulbs. This study will help to mitigate microbial contamination in Lilium species micropropagation for cryopreservation.