• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.585-590
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• 2008

Human tropic Porcine Endogenous Retroviruses (PERVs) are the major concern in zoonosis for xenotransplantation because PERVs cannot be eliminated by specific pathogen-free breeding. Recently, a PERV A/C recombinant with PERV-C bearing PERV-A gp70 showed a higher infectivity (approximately 500-fold) to human cells than PERV-A. Additionally, the chance of recombination between PERVs and HERVs is frequently stated as another risk of xenografting. Overcoming zoonotic barriers in xenotransplantation is more complicated by recombination. To achieve successful xenotransplantation, studies on the recombination in PERVs are important. Here, we cloned and sequenced proviral PERV env sequences from pig gDNAs to analyze natural recombination. The envelope is the most important element in retroviruses as a pivotal determinant of host tropisms. As a result, a total of 164 PERV envelope genes were cloned from pigs (four conventional pigs and two miniature pigs). Distribution analysis and recombination analysis of PERVs were performed. Among them, five A/B recombinant clones were identified. Based on our analysis, we determined the minimum natural recombination frequency among PERVs to be 3%. Although a functional recombinant envelope clone was not found, our data evidently show that the recombination event among PERVs may occur naturally in pigs with a rather high possibility.

• 자원환경지질
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• 제55권2호
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• pp.127-135
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• 2022

Excessive presence of As level in groundwater is a major health problem worldwide. In the Red River Delta in Vietnam, several million residents possess a high risk of chronic As poisoning. The As releases into groundwater caused by natural process through microbially-driven reductive dissolution of Fe (III) oxides. It has been extracted by Red River residents using private tube wells for drinking and daily purposes because of their unawareness of the contamination. This long-term consumption of As-contaminated groundwater could lead to various health problems. Therefore, a predictive model would be useful to expose contamination risks of the wells in the Red River Delta Vietnam area. This study used four machine learning algorithms to predict the As probability of study sites in Red River Delta, Vietnam. The GBM was the best performing model with the accuracy, precision, sensitivity, and specificity of 98.7%, 100%, 95.2%, and 100%, respectively. In addition, it resulted the highest AUC of 92% and 96% for the PRC and ROC curves, with Eh and Fe as the most important variables. The partial dependence plot of As concentration on the model parameters showed that the probability of high level of As is related to the low number of wells' depth, Eh, and SO₄, along with high PO₄^3- and NH₄⁺. This condition triggers the reductive dissolution of iron phases, thus releasing As into groundwater.

• 분석과학
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• 제12권3호
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• pp.256-259
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• 1999

Tyrosinase는 식물의 갈변현상에 관계가 있으며, 이의 방지를 위한 방법의 개발은 과학적인 관심사가 되고 있다. 솔잎으로부터 3개의 tyrosinase isozyme을 정제하여 그들의 활성에 영향을 주는 인자들을 분석하였다. L-ascorbic acid와 ${\beta}$-mercaptoethanol은 효소의 활성을 크게 저해하였다. 또한 sodium diethyldithio-carbamate도 효소활성에 대한 경쟁적 저해제였으며, $K_i$ 값은 $P_1$(0.030 mM), $P_2$(0.015 mM), $P_3$(0.019 mM)이였다. 반면 대부분의 금속이온들은 효소활성을 증가시켰다. L-DOPA를 기질로 사용했을 때 효소의 최적 pH는 9.0~9.5이며, 최적 온도는 $55{\sim}60^{\circ}C$를 나타내었다.

• 한국미생물·생명공학회지
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• 제46권4호
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• pp.390-394
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• 2018

Endoxylanase와 endoglucanase 유전자가 ADH1 프로모터 하류에 따로따로 삽입된 pAGX3 플라스미드를 함유한 Saccharomyces cerevisiae에서 endoxylanase와 endoglucanase 유전자는 성공적으로 발현되었으며, YPD 배지에서의 회분배양 결과, endoxylanase는 7.91 units/ml, endoglucanase는 0.43 units/ml에 달하는 총활성을 보였다. Yeast extract와 포도당을 간헐적으로 공급하는 유가배양에서 endoxylanase와 endoglucanase의 총활성은 24.9 units/ml과 0.84 units/ml을 각각 보였으며, 이는 회분배양에서 발현된 각각 활성의 3.1배와 2배에 해당되었다. 또한, 대부분의 endoxylanase와 endoglucanase 활성은 세포밖 배지에서 측정되어, 향후 이 재조합 효모는 섬유소(cellulose)와 xylan 혼합물의 동시당화 바이오공정 개발에 활용될 가능성이 높다 하겠다.

• 생명과학회지
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• 제12권4호
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• pp.464-468
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• 2002

대장균 트립토판 중합효소(tryptophan synthase) $\alpha$ 소단 위체의 96번, 139번 과 258번 자리를 돌연변이 시킨 이중 돌연변이체 P96L/F139W, P6L/F258W와 삼중 돌연변이체 P96L/F139W/F258W의 효소 활성도와 형광 분광계를 이용한 분광학적 성질을 조사하였다. 이중 돌연변이체의 효소 활성도는 야생형과 유사하나 삼중 돌연변이체는 40% 감소된 활성도를 가진다. P96L/F139W 와 P96L/F258W의 형광세기는 야생형에 비해 감소하였으나 P96L/F139W/F258W는 야생형에 비해 증가하였다. 효소 활성도와 형광 결과는 96번의 치환이 8번 알파구조와 4번 베타 구조와 4번 알파구조 사이의 loop의 안정성에 영향을 준 것을 나타낸다. 이 결과로부터 P96L/F139W/F258W는 야생형과 다른 3차 구조를 가지나 139번과 258면 주위는 더 조밀한 구조를 가지고 있다는 것을 보여준다.

• 대기
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• 제32권1호
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• pp.51-60
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• 2022

Corona Virus Disease 19 pandemic (COVID-19) causes many deaths worldwide, and has enormous impacts on society and economy. The COVID-19 was caused by a new type of coronavirus (Severe Acute Respiratory Syndrome Cornonavirus 2; SARS-CoV-2), which has been found that these viruses can be effectively inactivated by ultraviolet (UV) radiation of 290~315 nm. In this study, 90% inactivation time of the SARS-CoV-2 virus was analyzed using ground observation data from Brewer spectrophotometer at Yonsei University, Seoul and simulation data from UVSPEC for the period of 2015~2017 and 2020. Based on 12:00-13:00 noon time, the shortest virus inactivation time were estimated as 13.5 minutes in June and 4.8 minutes in July/August, respectively, under all sky and clear sky conditions. In the diurnal and seasonal variations, SARS-CoV-2 could be inactivated by 90% when exposed to UV radiation within 60 minutes from 10:00 to 14:00, for the period of spring to autumn. However, in winter season, the natural prevention effect was meaningless because the intensity of UV radiation weakened, and the time required for virus inactivation increased. The spread of infectious diseases such as COVID-19 is related to various and complex interactions of several variables, but the natural inactivation of viruses by UV radiation presented in this study, especially seasonal differences, need to be considered as major variables.

• 한국응용곤충학회지
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• 제61권1호
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• pp.255-266
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• 2022

본 연구에서는 감귤원에서 초생재배 유무(초생재배 W, 제초제 살포 NW)와 합성피레스로이드계 살포유무(살포 P, 무살포 NP)에 따른 귤응애의 개체군 동태를 구명하고자 수행되었다. 두 가지 기본적인 가설로 1) 초생재배는 천적의 서식처를 제공하여 천적의 정착을 높이므로 귤응애의 발생을 감소시키는 요인으로 작용하며, 2) 합성피레스로이드계는 천적을 제거하여 귤응애의 밀도를 증가시키는 요인으로 가정하였다. 관측된 천적 개체군(주로 이리응애류와 마름응애류)의 발생은 가정에 근거한 기대치와 크게 다르지 않았다. 2011년의 경우 NW+NP 처리구와 W+NP 처리구에서 차이가 있었으나, 2012년 실험에서는 기대치와 관측치가 거의 일치하였다. 전체적으로 약제효과가 뚜렷하게 나타나서 합성피레스로이드계 살포시 천적이 유의하게 감소하였다. 잡초효과는 엇갈리는 결과를 보였는데, 봄-유래 여름 개체군 대비 가을 개체군의 증가 등을 고려할 때 초생재배를 하는 경우 천적의 발생이 증가하였다. 다만, 합성피레스로이드계 살포구에서 귤응애가 감소하는 비이상적인 결과는 귤응애의 합성피레스로이드계에 대한 강한 기피성을 전제로 해석할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.251-253
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• 2018

최근 물가 불안정으로 인하여 농수축산물품 가격변동이 심화됨에 따라 소비자들은 제품 구매 시 정확한 기준 없이 시장의 마케팅 또는 경험과 감각에 의지하여 구매 활동을 하는 경향이 강해졌다. 이 논문에서 구현하는 애플리케이션의 핵심 기능은 공공데이터를 이용하여 실시간으로 농수축산물의 물가 지수를 간단하게 알아볼 수 있도록 도와준다. 또한, 구현하는 앱에 AI챗봇 및 음성인식 기능을 도입하는 동시에 자연어 처리와 핸즈프리 등의 편리성을 충족시켜 불안정한 물가에 휩쓸리는 소비자들에게 정확하고 편리하게 소비 지표를 알려주는 데 주요 목적이 있다.

• Journal of Plant Biotechnology
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• 제37권1호
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• pp.1-11
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• 2010

Floral scent emitted from many plants is the key factor for pollinator attraction and defense for survival in nature and is important industrial materials for perfumery as well. It is a complex mixture of various organic molecules with a high volatility or a high vapor pressure. In general, floral scents are divided into three categories, aliphatics, terpenoids, and phenylpropanoids/benzenoids, based on its origin. About 1,700 scent compounds have been identified and their biochemistry and molecular biology also have elucidated their biosynthesis from various flowering plants during the last ten years. In addition to improvement of vase life, flower color and shape, and/or disease resistance, floral scent is coming up to the major breeding target for improvement of marketability. Therefore, metabolic engineering can be an important tool in near future and may be able to facilitate the breeding program for novel cultivar selection and improvement of marketability of floricultural crops.

• 농업과학연구
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• 제39권4호
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• pp.595-602
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• 2012

Main objective is to examine visitors the image, awareness of Saemangeum to examine its image, awareness, expected projects, and areas of improvement. This can establish measures for publicity and nation-wide participation. Main results are as following. First, visitors are broadly distributed to all age groups. Majority of visiting is travel and rate of returning visit is high as well. Second, the Saemangeum project is positively recognized and it is expected to be a prime development of the west coast in the future. Third, TV has significantly contributed to the visit to Saemangeum but the internet has larger effects in younger generations. Furthermore, rest and experience facilities, accommodations, and food items are major areas of improvement. Fourth, visitors have high expectations for tours, leisure, and ecosystems. Therefore, efforts should be made to become the Mecca of greed-development and cultural tourism. Fifth, many people replied that Saemangeum is an assistance to the national development but water quality management should be continued. In addition, the public participation should be made centrically cultural and economical participations.