• KSBB Journal
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• 제6권3호
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• pp.231-240
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• 1991

Recently, developments of large scale and high density cell culture methods have been the objects of many researches, because the demand of various pharmaceutical products produced by animal cell culture has been rapidly increasing. The cell culture equipment should have the requirements such as sufficient oxygen transfer and mixing, low shear stress and surface tension, and small foaming. In order to develop a proper bioreactor meeting these requirements simultaneously, a perfluorocarbon having high solubility of oxygen was sprayed into the medium as an oxygen carrier instead of air. Also, a new impeller was developed and combined together with the perfluorocarbon spraying system so as to design a new bioreartor for cell cultivation. The new impeller had better characteristics of mixing and oxygen transfer than the paddle and cell-lift impellers based on the same, shear rate. But, it was observed that the volumetric oxygen transfer coefficient of the new bioreactor decreased with increasing cell density during E. coli fermentation.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 추계국제학술대회
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• pp.58-58
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• 2020

Xanthoceras sorbifolium Bunge (yellowhorn) is a woody tree in the soapberry family, Sapindaceae, native to northern China. This species has been identified as a major woody bioenergy plant for bio-diesel production because of high oil content in seed. But the flowers do not bear fruit well while the many flowers blooming. This study was performed to regenerate in vitro plantlet using adventitious shoot formation. To establish the protocol of plant regeneration, adventitious shoots formation rate in the culture of cotyledon of immature zygotic embryos was 68.6% in 1/2 MS medium with 0.5 mg l-1 BA and 3% sucrose (w/v). In the culture of cotyledons of mature zygotic embryos, induction of adventitious shoots was needed to contain high sucrose in pre-culture medium and the frequency of shoot induction was 64.4%. Multiple shoots were induced in 0.5 mg l-1 TDZ, and rooting of shoot was induced 4.0 mg l-1 IBA. Flow cytometry analysis revealed that all the regenerated plantlets were diploid.

• 복식문화연구
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• 제18권2호
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• pp.304-321
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• 2010

The purpose of this study was to investigate the sensation seeking tendency and knitwear purchase behaviors of high school girls. The data were obtained from 475 high school girls at 6 high schools located in Daejeon. The method of study is a survey consisted of sensation seeking tendency items, knitwear purchase behavior items and demographic attribution. Data were analyzed by frequency, variance, crosstabs, and correlation analysis using SPSS WIN 17.0 program. The results of study are as follows. First, high school girls generally liked knitwears by reason of comfort and activity. Most girls purchased the knitwears to wear ordinary casual wear(81.5%). They usually thought sweater and cardigan to be representative of knitwears. Also, they mostly purchased the knitwears of simple and active design, achromatic color, 100% cotton, and solid or simple stripe pattern. The design and price were considered as important evaluation criteria in knitwear purchase. The information sources used by them were store display, friends, and internet. Second, the knitwear purchase behaviors of high school girls showed the difference between groups with high- and low-sensation seeking tendency. The most important factor of knitwear purchase was an unique and characteristic design in high group and a simple and active design in low group. In conclusion, high school girls liked knitwears and had different knitwear purchase behaviors according to the sensation seeking tendency.

• KSBB Journal
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• 제15권3호
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• pp.219-225
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• 2000

Bacillus thuringiensis를 생물농약으로 이용하기 위해서는 고농도의 포자형성에 의한 높은 살충성의 8 -endotoxin를 생산하는 것이 중요하다. 따라서 본 연구에서는 B. thuringiensis의 고농도 배양에 의한 높은 포자형성 수율을 얻기 위하여 40%의 용존산 소량과 $28^{\circ}C$에서 여랴 가지 방법의 유가식 배양법을 검토하였다. 최종 배양액의 glucose 농도가 50 g/L가 되도록 하는 경우의 유가식 배양에서는 continuos fed-batch culture의 linear gradient f feeding 법에 의하여 $9.37{\times}109$ cell/mL의 최대 생존 세포 수와 8 8.33 X 109 spore/mL의 최대 포자 수를 얻었으며, 이때의 포자 형 성율은 88.9% 이었다 최종 배양액의 glucose 농도가 100 m/L가 되도록 하는 경우의 유가식 배양에서는 intermittent fed-batch culture의 pH-stat 법에 의하여 $1.35{\times}1010$cell/mL의 최대 생존 세포 수와 $1.35{\times}1010$ spore/mL의 최대 포자 수를얻었으며, 이 때의 포자 형성율은 97.8% 이엇다.

• ALGAE
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• 제30권1호
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• pp.35-47
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• 2015

The marine sand-dwelling dinoflagellate Polykrikos lebourae possesses obvious gold-brown pigmented plastids as well as taeniocyst-nematocyst complex structures. Despite of the presence of the visible plastids, previous attempts to establish this species in culture all failed and thus the unavailability of cultures of this species has posed a major obstacle to further detailed exploration of ecophysiology of the dinoflagellate. Here, we isolated P. lebourae from sandy sediment of an intertidal flat on Korean western coast, successfully established it in culture, and have been maintaining the stock culture over the past 3 years. Using this stock culture, we explored phagotrophy and potential prey resources of P. lebourae, growth and grazing responses of P. lebourae to different prey organisms, the effect of prey concentration on growth and grazing rates and gross growth efficiency (GGE) of P. lebourae when fed three different prey organisms, and the growth kinetics of P. lebourae under different light regimes. P. lebourae captured prey cells using a tow filament and then phagocytized them through the posterior end. The dinoflagellate was capable of ingesting a broad range of prey species varying in size, but not all prey species tested in this study supported its sustained growth. GGE of P. lebourae was extremely high at low prey concentration and moderate or low at high prey concentrations, indicating that P. lebourae grows heterotrophically at high prey concentrations but its growth seems to be more dependent on a certain growth factor or photosynthesis of plastids derived from the prey. In the presence of prey in excess, P. lebourae grew well at moderate light intensity of $40{\mu}mol$ photons $m^{-2}s^{-1}$, but did not grow at dim and high (10 or $120{\mu}mol$ photons $m^{-2}s^{-1}$) light intensities. Our results suggest that the benthic dinoflagellate P. lebourae is an obligate mixotroph, requiring both prey and light for sustained growth and survival.

• 한국수산과학회지
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• 제36권6호
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• pp.606-613
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• 2003

This study investigated the effects of food type (condensed freshwater Chlorella, dried Chlorella, dried Spirulina, dried Schizochytrium, baker's yeast and $\omega-yeast$) and amount, and supplementation of vitamin $B_{12}$ on the growth of freshwater rotifer (Brachionus calyciflorus) in high density culture. Growth of rotifers fed condensed freshwater Chlorella was the highest and its density ranged $7.65-8.14{\times}10^3\;inds./mL.$ The primary lipid acids of rotifers fed condensed freshwater Chloyella were linoleic and linolenic, and their amount ($\%$ of total fatty acids) were $48.8\%\;and\;26.8\%,$ respectively. This suggests that condensed freshwater Chlorella would be an effective diet for high quality and quantity rotifers, which in turn serve as live food for freshwater fish larvae. Growth rate of rotifers with Chlorella supplementation increased as amount of supplementation increased up to 1.5 and 2.5 mg at 28 and $32^{\circ}C$, respectively. However, undissolved ammonia toxicity and packing volume of Chlorella in culture medium, reached the optimal conditions for the stable and effective cultivation of rotifers when amount of condensed freshwater Chlorella was 1.5 mg in dry weight per 1,000 rotifers at $28^{\circ}C\;and\;32^{\circ}C$ Growth of rotifers in condensed freshwater Chlorella with vitamin $B_{12}$ supplementation was significantly higher than that of rotifers without supplementation. However, no significant difference was found among the different concentrations of vitamin $B_{12}.$ Therefore, vitamin $B_{12}$ could improve the growth of rotifers (B. calyciflorus).

• 한국수산과학회지
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• 제44권6호
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• pp.665-670
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• 2011

The rotifer Brachionus plicatilis is one of the most important food organisms in aquaculture. The resting eggs produced by mictic female rotifers are easily stored and hatched, making them useful as the starter for the mass culture of rotifers in marine larval culture. This study examined the optimum preservation method for resting eggs to ensure a high hatching rate. To produce resting eggs, the marine rotifer B. plicatilis was cultured with Nannochloris oculata (KMMCC 16). The resting eggs were harvested and cryopreserved using 5% and 10% methanol (MeOH), dimethylsulfoxide (DMSO), and glycerol as cryoprotectant agents (CPAs). The cryopreservation comprised slow or rapid freezing and the resting eggs were stored for one month in liquid nitrogen ($-196^{\circ}C$). The resting eggs were also dried at different temperatures (30, 40, and $50^{\circ}C$) and for different times (1, 2, and 3 h). In general, the hatching rates of the resting eggs preserved with CPA were higher than those without CPA and the slow freezing method was better than the rapid freezing method. However, the optimum CPA concentration for the hatching rate of the resting eggs varied with the freezing method and kind of CPA, and the CPA also affected the viability of the resting eggs. Dried resting eggs had a high, rapid hatching rate over 80%. The moisture content of the resting eggs cryopreserved in liquid nitrogen affected the hatching rate. Drying at $30^{\circ}C$ for 1 hour resulted in a high hatching rate of the resting eggs. In conclusion, drying at $30^{\circ}C$ for 1 hour and preservation in liquid nitrogen with the slow freezing method, without CPA, is recommended for a high hatching rate (ca. 95%) of rotifer resting eggs.

• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1430-1437
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• 2021

Cronobacter sakazakii is an opportunistic pathogenic bacterium found in powdered infant formula and is fatal to neonates. Antibiotic resistance has emerged owing to overuse of antibiotics. Therefore, demand for high-yield bacteriophages as an alternative to antibiotics has increased. Accordingly, we developed a modified mass-production method for bacteriophages by introducing a two-stage self-cycling (TSSC) process, which yielded high-concentration bacteriophage solutions by replenishing the nutritional medium at the beginning of each process, without additional challenge. pH of the culture medium was monitored in real-time during C. sakazakii growth and bacteriophage CS01 propagation, and the changes in various parameters were assessed. The pH of the culture medium dropped to 5.8 when the host bacteria reached the early log phase (OD₅₄₀ = 0.3). After challenge, it decreased to 4.65 and then recovered to 4.94; therefore, we set the optimum pH to challenge the phage at 5.8 and that to harvest the phage at 4.94. We then compared phage production during the TSSC process in jar-type bioreactors and the batch culture process in shaker flasks. In the same volume of LB medium, the concentration of the phage titer solution obtained with the TSSC process was 24 times higher than that obtained with the batch culture process. Moreover, we stably obtained high concentrations of bacteriophage solutions for three cycles with the TSSC process. Overall, this modified TSSC process could simplify large-scale production of bacteriophage CS01 and reduce the unit cost of phage titer solution. These results could contribute to curing infants infected with antibiotic-resistant C. sakazakii.

• Korean Chemical Engineering Research
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• 제44권1호
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• pp.58-64
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• 2006

본 연구에서는 인체 두피조직에서 미세수술법을 이용하여 모낭을 성공적으로 분리하였으며 다양한 조건으로 액침기관배양을 수행하였다. 우태아 혈청첨가시 모낭의 길이 성장이 저해되는 것으로 확인되어 무혈청 배지 조성을 시도하였다. 무혈청 배지로는 모낭 기관배양에 널리 이용되는 Williams'E medium을 기본으로 하는 Philpott medium과 자체 개발한 고농도 아미노산과 비타민(B군) 조성의 DHGM(Dongguk hair growth medium)을 이용하였다. 그리고 IMDM은 DHGM의 비교 대조군으로 이용하였다. 연구 결과 Philpott medium과 IMDM으로 배양한 모낭은 구조상으로는 길이 성장이 각각 9일과 12일 정도에 멈추며, 낮은 알카라인 포스파테이즈 발현, CK19 발현이 거의 없는 것으로 보아 세포사멸에 의한 퇴화(regression)가 빠르게 일어나는 것으로 판단되었다. 반면, DHGM으로 배양한 모낭은 상대적으로 긴 기간 동안 성장기의 구조를 보이며 25일까지 지속적인 길이 증가 및 3배 높은 알카라인 포스파테이즈 발현, 전반적인 CK19 발현을 나타내었다. 따라서 고농도의 아미노산 및 비타민 배지 조성이 생체 외에서 모낭을 장기간 배양하는데 중요한 역할을 하는 것으로 판단된다. 이러한 배양 방법은 장기간 검사를 필요로 하는 모낭에 대한 기초 생물학적 연구뿐만 아니라 새로운 탈모치료제의 효능 평가 분야에 이용될 수 있을 것이다.

• 한국가축번식학회지
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• 제24권3호
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• pp.289-297
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• 2000

본 연구는 체외성숙, 수정된 돼지 수정란의 체외발달에 다양한 단백질 공급원의 첨가 및 공배양이 미치는 영향을 조사하기 위해서 수행하였다 본 실험에서 얻은 결과들을 하면 다음과 같다. 1. 체외성숙, 수정된 돼지 수정란을 BSA의 농도가 각각 0.4, 0.8 및 3.2% 첨가된 NCSU 23 배양액 내에서 체외배양하였을 때, 배반포 단계까지의 발달율은 각각 22.9, 18.4 및 14.6%로서 BSA의 농도가 높을수록 체외발달율은 감소하는 경향을 나타내었다. 높은 농도의 BSA(3.2%)에서 발달한 배반포의 평균 세포수(36.1$\pm$11.8)는 0.4 및 0.8% BSA 그룹의 평균 세포수 (각자 53.2$\pm$27.4, 61.2$\pm$22.5)보다 유의적으로 적은 수를 나타내었다 (P<0.05). 이러한 결과는 높은 농도의 BSA가 돼지 체외수정란의 체외발달을 저해한다는 것을 시사하였다. 2. FBS의 농도가 10% 및 20%로 첨가된 배양액에서 배양된 돼지 체외 수정란의 체외발달율과 평균 세포수는 차이가 없었다. 3. 생쥐나 돼지 태아섬유아세포와의 공배양은 돼지 체외수정란의 체외발달에 오히려 부정적 효과를 나타내었다. 본 연구 결과는 돼지 수정란의 체외배양에 있어서 단백질 공급원인 BSA나 FBS의 첨가 농도에 따라서는 수정란의 발달 및 질적 향상을 도모할 수 없었으며, 섬유아세포와의 공배양도 돼지 체외수정란의 발달에 부정적 효과가 있다는 것을 제시하였다.