• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.637-645
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• 2011

Production of recombinant proteins by excretory expression has many advantages over intracellular expression in Escherichia coli. Hyperexpression of a secretory exoglucanase, Exg, of Cellulomonas fimi was previously shown to saturate the SecYEG pathway and result in dramatic cell death of E. coli. In this study, we demonstrated that overexpression of the PspA in the JM101(pM1VegGcexL-pspA) strain enhanced excretion of Exg to 1.65 U/ml using shake-flask cultivation, which was 80% higher than the highest yield previously obtained from the optimized JM101(pM1VegGcexL) strain. A much higher excreted Exg activity of 4.5 U/ml was further achieved with high cell density cultivation using rich media. Furthermore, we showed that the PspA overexpression strain enjoyed an elevated critical value (CV), which was defined as the largest quotient between the intracellular unprocessed precursor and its secreted mature counterpart that was still tolerable by the host cells prior to the onset of cell death, improving from the previously determined CV of 20/80 to the currently achieved CV of 45/55 for Exg. The results suggested that the PspA overexpression strain might tolerate a higher level of precursor Exg making use of the SecYEG pathway for secretion. The reduced lethal effect might be attributable to the overexpressed PspA, which was postulated to be able to reduce membrane depolarization and damage. Our findings introduce a novel strategy of the combined application of metabolic engineering and construct optimization to the attainment of the best possible E. coli producers for secretory/excretory production of recombinant proteins, using Exg as the model protein.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.842-848
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• 2013

Developments of Solid-State Gyroscopy during last decades are impressive and were based on thin-walled shell resonators like HRG or CRG made from fused quartz or leuko-sapphire. However, a number of design choices for inertial-grade gyroscopes, which can be used for high-g applications and for mass- or middle-scale production, is still very limited. So, considerations of fundamental physical effects in solids that can be used for development of a miniature, completely solid-state, and lower-cost sensor look urgent. There is a variety of different types of bulk acoustic (elastic) waves (BAW) in anisotropic solids. Shear waves with different variants of their polarization have to be studied especially carefully, because shear sounds in glasses and crystals are sensitive to a turn of the solid as a whole, and, so, they can be used for development of gyroscopic sensors. For an isotropic medium (for a glass or a fine polycrystalline body), classic Lame's theorem (so-called, a general solution of Elasticity Theory or Green-Lame's representation) has been modified for enough general case: an elastic medium rotated about an arbitrary set of axes. Travelling, standing, and mixed shear waves propagating in an infinite isotopic medium (or between a pair of parallel reflecting surfaces) have been considered too. An analogy with classic Foucault's pendulum has been underlined for the effect of a turn of a polarizational plane (i.e., an integration effect for an input angular rate) due to a medium's turn about the axis of the wave propagation. These cases demonstrate a whole-angle regime of gyroscopic operation. Single-crystals are anisotropic media, and, therefore, to reflect influence of the crystal's rotation, classic Christoffel-Green's tensors have been modified. Cases of acoustic axes corresponding to equal velocities for a pair of the pure-transverse (shear) waves have of an evident applied interest. For such a special direction in a crystal, different polarizations of waves are possible, and the gyroscopic effect of "polarizational precession" can be observed like for a glass. Naturally, formation of a wave pattern in a massive elastic body is much more complex due to reflections from its boundaries. Some of these complexities can be eliminated. However, a non-homogeneity has a fundamental nature for any amorphous medium due to its thermodynamically-unstable micro-structure, having fluctuations of the rapidly-frozen liquid. For single-crystalline structures, blockness (walls of dislocations) plays a similar role. Physical nature and kinematic particularities of several typical "drifts" in polarizational BAW gyros (P-BAW) have been considered briefly too. They include irregular precessions ("polarizational beats") due to: non-homogeneity of mass density and elastic moduli, dissymmetry of intrinsic losses, and an angular mismatch between propagation and acoustic axes.

• Animal Bioscience
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• 제34권8호
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• pp.1392-1402
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• 2021

Objective: The growth rate of pigs is related to differentiation and proliferation of muscle cells, which are regulated by growth factors and expression of growth-related genes. Thus, the objective of this study was to establish optimal culture conditions for Jeju black pig (JBP) muscle cells and determine the relationship of various factors involved in muscle growth with the proliferation of JBP muscle cells. Methods: Muscles were taken from the femur skeletal muscle of JBP embryos. After isolation of the muscle cells, cells were cultured in a 6-well plate under four different culture conditions to optimize culture conditions for JBP muscle cells. To analyze proliferation rate of JBP muscle cells, these muscle cells were seeded into 6-well plates at a density of 1.5×10⁵ cells per well and cultured for 3 days. Western blot and quantitative real-time polymerase chain reaction were applied to verify the myogenic differentiation 1 (MyoD) expression and growth-related gene expression in JBP muscle cells, respectively. Results: We established a muscle cell line from JBP embryos and optimized its culture conditions. These muscle cells were positive for MyoD, but not for paired box 7. The proliferation rate of these muscle cells was significantly higher in a culture medium containing bFGF and epidermal growth factor + basic fibroblast growth factor (EGF+bFGF) than that without a growth factor or containing EGF alone. Treatment with EGF and bFGF significantly induced the expression of MyoD protein, an important transcription factor in muscle cells. Moreover, we checked the changes of expression of growth-related genes in JBP muscle cells by presence or absence of growth factors. Expression level of collagen type XXI alpha 1 gene was changed only when EGF and bFGF were added together to culture media for JBP muscle cells. Conclusion: Concurrent use of EGF and bFGF increased the expression of MyoD protein, thus regulating the proliferation of JBP muscle cells and the expression of growth-related genes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권4호
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• pp.291-299
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• 2005

Objectives : It is well known that cigarette smoking is harzardous to the osseointegration of dental implant, due to the impaired wound healing accompanied by reduced alveolar bone density. The aim of this study is to evaluate the influence of cigarette smoke on the implant osseointegration by the time factor consideration. Materials and methods : Twenty-four male Spraque-Dawley rats (8 weeks, weighting 200 to 250g) were used in this study. In the experimental group, 13 rats were exposed to cigarette smoke, 8 minutes per day during 6 weeks, and 12 rats in the control group were not exposed at any time. RBM (Resorbed blasting media) surfaced implant (diameter 3.3mm, length 5.0mm, AVANA Co., Korea) was placed in the right femur of each rat. Each implant with surrounding bone was prepared with microtome (cutting band 0.2mm$^{(R)}$, EXAKT Co., Germany) after 1 day, 2, 4, 8 and 12 weeks and stained with toluidine blue (1%). Another clinical investigation of each implant was also done at each evaluation time. Results : Clinical investigation around implant fixture showed that there were no significant differences between the control and experimental group. Microscopic observation around implant fixture showed that there were significant differences between the control and experimental group at the initial stage after implant fixture installation. Experimental group showed a decreased bone to implant contact within 4 weeks compared to control group, but showed similar characteristics after 4 weeks. Conclusion : Smoking inhalation effect on the dental implant showed the impaired wound healing by vasoconstriction and decreased intramedullary blood flow at initial stage of osseointegration. This experimental results can be clinically useful to the implant surgery of smoking patients.

• 한국균학회지
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• 제23권3호통권74호
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• pp.226-231
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• 1995

팽이버섯은 최근(最近)에 생산(生産)과 소비(消費)가 촉진(促進)되어 재배면적(栽培面積)이 급증(急增)하고 있는데 이에 소요되는 재배용(栽培用) 톱밥배지(培地) 제조시(製造時)에 부화장(孵化場) 부산물(副産物)인 계란껍질의 첨가효과(添加效果)를 구명(究明)하기 위하여 몇 가지 시험(試驗)을 수행한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 배지재료(培地材料)의 화학적(化學的) 성질 중 계란껍질은 전탄소(全炭素) 20.7%, 전질소(全窒素) 0.81%이고 인과 칼슘함량은 2,530 ppm과 44.37%로 톱밥보다 많았다. 2. 배지재료 배합시 계란껍질을 첨가하면 균사생장(菌絲生長) 및 초발용소요일수(初發茸所要日數)는 무처리구(無處理區)와 차이가 없었으나 수량(收量)이 증수(增收)되는 경향이었으며 특히 계란껍질을 15% 첨가할 때 자실체(子實體) 수량(收量)이 23% 정도 증수(增收)되었다. 그러나 20% 이상 첨가시는 수량이 감소되는 경향이 있다. 3. 팽이버섯 품질(品質)은 계란껍질 $5{\sim}15%$ 첨가시 버섯 대길이 12.8 cm, 대직경 3 mm, 갓직경 9 mm로 무처리구(無處理區)와 비슷하였으나 유효경수(有效莖數)는 무처리구(無處理區)보다 11% 많았다. 4. 톱밥배지 제조시(製造時) 계란껍질을 15%까지 첨가(添加)하면 배지(培地)의 물리성(物理性)이 개선(改善)되고 인과 칼슘함량이 높아 자실체(子實體) 수량(收量)과 품질(品質)이 향상(向上)되었다.

• 생물환경조절학회지
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• 제15권4호
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• pp.289-295
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• 2006

온실의 환기연구를 위한 CFD 시뮬레이션 모델에 토마토 작물을 설계함에 있어서 우선적으로 작물군의 기하학적 형상 설계 및 이의 공기 항력계수를 찾고자 하였다. 작물군 형상을 간단한 형태의 공기투과성 매체로 설계하고 이의 공기저항의 물리적 특성을 풍동실험을 통하여 구하였다. 토마토 작물군과 작물군 사이에서 측정된 값과 작물군 중앙부에서 측정되어진 값들을 분리하여 계산하여 된 결과 공기저항값인 항력계수 $C_d 값은 각각 0.2551와 0.2621로 나타났다. 최종적으로 이들의 평균값인 0.26을 Fluent CFD 프로그램의 작물군 공기투과성 매체의 x, y, z축의 내부저항값으로 입력되었다. 이 실험결과를 이용하여 전산유체역학 (CFD)을 이용한 시설내 작물군이 존재하는 경우의 온실 환기연구를 효과적으로 수행할 수 있게 되었다. 또한 풍동을 이용한 작물의 공기저항 연구를 위한 실험방법을 개발하여 앞으로도 다양한 작물들을 대상으로 공기유동의 물리적 특성연구를 수행할 수 있게 되었다.

• 한국균학회지
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• 제37권2호
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• pp.144-149
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• 2009

The occurrences of the major diseases and the densities of air-born microbes were surveyed in the cultivation facilities for oyster mushroom (Pleurotus ostreatus), king oyster mushroom (Pleurotus eryngii), and enoki mushroom (Flammulina velutipes) in different areas of Korea. Green mold disease was most often developed in oyster mushroom bed cultivation with the disease incidence rate of approximate 10% while the disease incidences from bottle and plastic envelop cultivation were less than 1~2%. In the bed cultivation, the major air-born microbes in the growth room were Aspergillus, Penicillium, Trichoderma, and Curvularia with the total fungal population density of 567~1,297 CFU/$m^3$ . However, only Trichoderma and Penicillium were detected in the growth rooms and innoculation rooms of bottle and plastic envelop cultivation with the densities of 350~700 CFU/$m^3$ and 160~260 CFU/$m^3$, respectively. The bacterial diseases become evident in the growth rooms of bottle and plastic envelop cultivation with the approximate incidence rate of 10%. The identified bacterial species were Brevibacillus levelkil, Rhizobium radiobacter, Brevundimonas vesicularis, Pseudomonas mosselii, Microbacterium testaceum. Sphingomonas panmi, Sphingomonas yabuuchiae, Paracocus dinitrificans, Curtobacterium flaccumfaciens pv. flaccumfaciens and some unidentified bacteria with the densities of 40~6,359 CFU/$m^3$ in the growth rooms and 9 CFU/$m^3$ in the inoculation room. This study indicated that the green mold disease by fungal strains was the major mushroom disease in the bed cultivation and suggested that the contamination of bacteria and fungi together in the growth media could result in severe production loss. The plastic envelope and bottle cultivation were evidenced to be less susceptible to such contaminations.

• 대한환경공학회지
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• 제35권1호
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• pp.45-56
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• 2013

본 연구는 낙동강수계의 잔류의약물질을 관리하기 위한 기초자료로 제시되었다. 낙동강 본류에서 Iopromide는 $0.0015{\sim}0.37{\mu}g/L$, Mefenamic acid은 $0.0087{\sim}0.056{\mu}g/L$, Diclofenac은 $N.D.{\sim}0.01{\mu}g/L$, Atenolol은 $N.D.{\sim}0.024{\mu}g/L$, Propranolol은 $N.D.{\sim}0.0038{\mu}g/L$, Lincomycin은 $0.0005{\sim}0.038{\mu}g/L$, Trimethoprim은 $N.D.{\sim}0.0083{\mu}g/L$의 농도범위로 검출되었다. 유역의 하수처리장에서는 대부분 고농도로 검출되었으며, 특히 Iopromide가 최고 $5.38{\mu}g/L$까지 검출되었다. 축산폐수처리장에서는 린코마이신이 최고 $477{\mu}g/L$로 가장 높게 검출되었다. 조사결과, 낙동강 본류에서 의약물질은 구미하수처리장과 대구 금호강의 유입으로 농도가 높아져 인구 산업밀집지역의 영향이 큰 것으로 판단된다. 따라서 낙동강의 잔류의약물질을 효율적으로 관리하기 위해서는 금호강과 하 폐수처리장을 지속적으로 모니터링하고 관리하는 것이 바람직한 것으로 사료된다.

• Tuberculosis and Respiratory Diseases
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• 제60권2호
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• pp.187-193
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• 2006

배 경 : 결핵균의 성장 속도가 늦은 이유가 mammalian cell이나 대장균에 비해 결핵균 AK의 매우 낮은 활성도에 의한 것이라는 추측으로부터 AK1과 유사한 촉매능을 나타내는 AKmt 돌연변이 유전자와 human muscle-type AK 합성 유전자(AK1)를 각각 Mycobacterium/E.coli 발현벡터에 재조합(pMVAKmtDM, pEMAK1)하여 성장 속도가 매우 느린 BCG에 형질전환함으로써 이들 단백질들의 촉매능에 의한 성장 속도 변화가 일어나는지를 확인하고자 하였다. 방 법 : Human AK1의 촉매 활성도와 유사하도록 결핵균 AK (AKmt)유전자의 ATPbd와 LID domain을 돌연변이하여 제조한 유전자(AKmtDM)와 human muscle-type adenylate kinase 합성 유전자(AK1)를 Mycobacterium/E.coli 발현벡터에 클로닝하여 재조합 BCG를 제조하였고, 이들 재조합 BCG와 BCG Pasteur $1173P_2$ (wild-type)를 7H9 액체배지에 접종하여 2-3 일 간격으로 $A_{600}$ 값을 측정하였다. 결 과 : 재조합 BCG의 성장 속도는 Wild-type BCG의 성장 속도에 비해 변화가 없었다. 결 론 : 결핵균 adenylate kinase의 정확한 기능은 알 수 없으나, adenylate kinase의 촉매 활성도의 증가는 BCG의 성장 속도에는 영향을 주지 않는 것으로 판단된다.

• 한국버섯학회지
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• 제15권3호
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• pp.145-149
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• 2017

느타리버섯 재배에서 영양원으로 가장 많이 사용하고 있는 면실박 대체용 유기성자원을 선발한 결과 보리가루가 대체 배지재료로 충분할 것으로 판단된다. 면실박대체용 보리가루가 5% 첨가된 배지에서는 11.4 cm로 균사생장이 가장 빨랐으며, 보리가루가 30% 첨가된 배지에서는 9.0 cm로 균사생장이 가장 느렸다. 보리가루 첨가량에 따른 균사밀도는 보리가루 첨가량이 5%와 10%에서 균사밀도가 조금 낮았지만 다른 처리간에는 뚜렷한 차이가 없었다. 자실체 수량은 대조구가 155.9 g/850 ml였고, 보리가루와 면실박이 10% 첨가된 처리가 158 g/850 ml으로 가장 높았고, 보리가루만 첨가된 처리에서는 수량이 대조구보다 낮았다. 갓의 직경과 대경도는 보리가루 10%와 면실박 10% 처리에서 가장 높았고, 대의 굵기와 갓 경도는 보리가루만 10% 첨가된 처리에서 가장 높았다. 갓의 색도를 측정한 결과 L값은 보리가루만 10% 첨가된 처리에서 가장 높았고, a, b 값은 처리간에 뚜렷한 차이를 보이지 않았다. 느타리 종균 접종전 혼합배지의 pH는 4.7~5.0, 총질소함량은 1.7~2.2로 대조구에 비해 약간 낮은 경향을 보였고, 총탄소함량은 44.6~45.0로 대조구와 유의한 차이를 보이지 않았으며, 처리간에도 뚜렷한 차이를 보이지 않았다. 반면에 Cu, Fe 등 미량원소 함량은 대조구에 비해 낮은 경향을 보였다.