• 대한의용생체공학회:의공학회지
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• 제13권2호
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• pp.155-164
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• 1992

Attachment and growth of mouse flbroblast cells on block copolypeptides were studied in the pres once or absence of serum proteins. Cells are rapidly attached to she polymer surface within 30 min regardless of substrate in the presence of serum. The number of flbroblast cells attached on the poly mer surface coated by collagen was larger than thats on the bare surface. Attachment of cells Is as a whole suppressed to a low level by the addltion of sodium azide in the absence of serum. Thls suE gests that the active attachment of cells requires the biological metabolism taking place on polymer substrates. In the presence of serum protein, flbroblast cells are more rapidly grown on the bolck co polymer consisting of poly(T-benzyl L-glutamate) (PBLG) and polyoxypropylene(POP) than on other block copolymers. These results were in agreement wish the data obatlned by an Inverted ml croscope.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1681-1691
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• 2017

This study investigated the effect of proline addition on the salt tolerance of Tetragenococcus halophilus. Salt stress led to the accumulation of intracellular proline in T. halophilus. When 0.5 g/l proline was added to hyperhaline medium, the biomass increased 34.6% (12% NaCl) and 27.7% (18% NaCl) compared with the control (without proline addition), respectively. A metabolomic approach was employed to reveal the cellular metabolic responses and protective mechanisms of proline upon salt stress. The results showed that both the cellular membrane fatty acid composition and metabolite profiling responded by increasing unsaturated and cyclopropane fatty acid proportions, as well as accumulating some specific intracellular metabolites (environmental stress protector). Higher contents of intermediates involved in glycolysis, the tricarboxylic acid cycle, and the pentose phosphate pathway were observed in the cells supplemented with proline. In addition, addition of proline resulted in increased concentrations of many organic osmolytes, including glutamate, alanine, citrulline, N-acetyl-tryptophan, and mannitol, which may be beneficial for osmotic homeostasis. Taken together, results in this study suggested that proline plays a protective role in improving the salt tolerance of T. halophilus by regulating the related metabolic pathways.

• Macromolecular Research
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• 제11권1호
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• pp.2-8
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• 2003

The self-assembly of polymers can lead to supramolecular systems and is related to the their functions of material and life sciences. In this article, self-assembly of Langmuir-Blodgett (LB) films, polymer micelles, and polymeric nanoparticles, and their biomedical applications are described. LB surfaces with a well-ordered and layered structure adhered more cells including platelet, hepatocyte, and fibroblast than the cast surfaces with microphase-separated domains. Extensive morphologic changes were observed in LB surface-adhered cells compared to the cast films. Amphiphilic block copolymers, consisting of poly(${\gamma}$-benzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) [or poly(N-isopropylacrylamide) (PNIPAAm)] as the hydrophilic one, can self-assemble in water to form nanoparticles presumed to be composed of the hydrophilic shell and hydrophobic core. The release characteristics of hydrophobic drugs from these polymeric nanoparticles were dependent on the drug loading contents and chain length of the hydrophobic part of the copolymers. Achiral hydrophobic merocyanine dyes (MDs) were self-assembled in copolymeric nanoparticles, which provided a chiral microenvironment as red-shifted aggregates, and the circular dichroism (CD) of MD was induced in the self-assembled copolymeric nanoparticles.

• Bulletin of the Korean Chemical Society
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• 제8권4호
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• pp.318-324
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• 1987

Experimental results for viscous flow of poly (${\gamma}$ -methyl L-glutamate) solutions have been published elsewhere. The data of $[{\eta}]^f / [{\eta}]^0$ are expressed by the following equation, $\frac{[{\eta}^f]}{[{\eta}^{\circ}]}=1-\frac{A}{\eta^\circ}{1-\frac{sin^{-1}[{\beta}_2(f/{\eta}_0)\;{e}xp\;(-c_2f^2/{\eta}_0^2kT)]}{{\beta}_2f/{\eta}_0}$ (A1) where $[{\eta}]^f\; and\; [{\eta} ]^0$ are the intrinsic viscosity at shear stress f and zero, respectively, $ A{\equiv}lim\limits_{C{\rightarrow}0}[(1/C)(X_2/{\alpha}_2)({\beta}_2/{\eta}_0)],{\eta}_0$ viscosity of the solvent, ${\beta}_2$ is the relaxation time of flow unit 2, $c_2$ is a constant related to the elasticity of flow unit 2. The theoretical derivation of Eq.(A1) is given in the text. The experimental curves of $[{\eta}]^f / [{\eta}]^0$ vs. log f are compared with the theoretical curves calculated from Eq.(A1) with good results. Eq.(A1) is also applied to non-biopolymeric solutions, and it was found that in the latter case $c_2 = 0.$ The reason for this is explained in the text. The problems related to non-Newtonian flows are discussed.

• Bulletin of the Korean Chemical Society
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• 제8권4호
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• pp.332-335
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• 1987

This paper is a continuation of our previous $paper,^1$ and deals with Eq.(1) (see the text), which was theoretically derived in the $paper,^1$$ [{\eta}]^f\; and\; [{\eta}]^0$ is the intrinsic viscosity at stress f and f = O, respectively. Equation (1) predicts how $[{{\eta}}]^f / [{\eta}]^0$ changes with stress f, relaxation time ${\beta}_2$ of flow unit 2 and a constant $c_2$ related with the elasticity of molecular spring of flow unit 2. In this paper, Eq.(1) is applied to a biopolymer, e.g., poly (${\gamma}$-benzyl L-glutamate), and nonbiopolymers, e.g., polyisobutylene, polystyrene, polydimethylsiloxane and cellulose triacetate. It was found that the $c_2$ factor is zero for non-biopolymers while $c_2{\neq}0$ for biopolymers as found $previously.^1$ Because of the non-Newtonian nature of the solutions, the ratio $[{{\eta}}]^f / [{\eta}]^0$ drops from its unity with increasing f. We found that the smaller the ${\beta}_2,$ the larger the $f_c$ at which the viscosity ratio drops from the unity, vice versa.

• 한국식품영양과학회지
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• 제46권8호
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• pp.979-985
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• 2017

본 연구는 유산균에 의한 gamma aminobutyric acid(GABA)의 생산 및 쌀겨 추출물을 이용한 최적 배지의 제조를 목표로 하고 electrostatic spray는 곡물에 GABA 함량을 증진시키기 위해 사용하였다. 분리한 Lactobacillus brevis CFM11을 MRS 배지를 이용하여 최적 조건($37^{\circ}C$, 24시간, pH 6.5)에서 배양시킨 결과, $600.12{\mu}g/mL$의 GABA 생성량을 나타냈고 0.8% MSG를 함유한 MRS 배지에서 배양시켰을 때 $2,002.93{\mu}g/mL$의 GABA 생성량을 나타냈다. 미강 추출물 배지에 MSG 0.4%, sucrose 2%, skim milk 1%, magnesium sulfate 0.2%를 첨가했을 때 GABA 생산량은 $585.80{\mu}g/mL$로 나타났다. 최적화 배지에 L. brevis CFM11을 배양시켜 얻은 GABA를 쌀 표면에 electrostatic spray 처리 후 GABA량은 $228.10{\mu}g/g$으로 나타난 반면, 아무것도 처리하지 않은 곡류에서의 GABA량은 $32.23{\mu}g/g$이었다. 이러한 결과로 보아 미강 추출물은 GABA 생산을 위한 MRS 배지의 대체물로서 산업적인 가치를 증가시킬 수 있을 것으로 판단된다.

• 한국식품영양과학회지
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• 제39권9호
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• pp.1391-1398
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• 2010

홍삼 추출액 제조 후 생산되는 부산물인 홍삼박의 식품 소재화를 위해서 열풍 건조시킨 후 초미세 분말화 하였으며, 쑥 분말 첨가에 따른 고초균 발효 특성을 조사하였다. 홍삼박 분말에 탈지대두분말 3%와 monosodium glutamate(MSG) 2%, 쑥을 농도별(0~3%)로 첨가하여 발효하여 분석하였다. 홍삼박 발효물의 tyrosine 함량은 쑥 3% 첨가 시 581.3 mg% 로 가장 높은 함량을 나타낸 반면 protease 활성은 쑥을 첨가할수록 감소하는 경향을 나타냈으며 쑥을 첨가하지 않은 구에서 277.5 unit/g으로 가장 높은 활성을 나타냈다. 점조도 측정 결과 쑥 3% 첨가 시 $8.8\;Pa{\cdot}s^n$으로 가장 높게 나타났고, 점질물 함량은 쑥을 첨가하지 않은 구에서 11.5%로 가장 높은 함량을 나타냈다. 고분자 점질물인 PGA함량을 GPC를 이용하여 측정한 결과 쑥을 첨가하지 않은 구에서 15.9 g/kg 이었으며 분자량은 1,100 kDa으로 나타났다. 첨가된 MSG 전환율을 약 80% 정도로 나타냈으며, 쑥 첨가에 따른 전환율에 효과는 볼 수 없었다. DPPH radical 소거활성은 쑥 3% 첨가된 발효물에서 물과 70% 주정 추출물 각각 $IC_{50}$값이 0.62 mg/mL, 0.57 mg/mL로 나타났다. ABTS radical 소거 활성은 쑥 3% 첨가 시 물 과 70% 주정 추출물에서 각각 $IC_{50}$값은 1.24 mg/mL, 1.34 mg/mL로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.789-796
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• 2000

In order to analyze the effects of tktA, $aroF^{FBR}$, and aroL expression in a tryptophan-producing Escherichia coli, a series of plasmids carrying the genes were constructed. Introduction of tktA, $aroF^{FBR}$, and aroL into the E. coli strain resulted in approximately 10-20 fold increase in the activities of transketolase, the feedback inhibition-resistant 3-deoxy-D-arabinoheptulsonate-7-phosphate synthase, and shikimate kinase. Expression of $aroF^{FBR}$ in the aroB mutant strain of E. coli resulted in the accumulation of 10 mM of 3-deoxy-D-arabinoheptulsonate-7-phosphate (DAHP) in the medium. Simultaneous expression of tktA and $aroF^{FBR}$ in the strain further increased the amount of excreted DAHP to 20 mM. In contrast, the mutant strain which has no gene introduced accumulated 0.5 mM of DAHP. However, the expression of tktA and $aroF^{FBR}$ in a tryptophan-producing E. coli strain did not lead to the increased production of tryptophan, but instead, a significant amount of shikimate, which is an intermediate in the tryptophan biosynthetic pathway, was excreted to the growth medium. Despite the fact that additional expression of shikimate kinase in the strain could possibly remove 90% of excreted shikimate to 0.1 mM, the amount of tryptophan produced was still unchanged. Removing shikimate using a cloned aroL gene caused the excretion of glutamate, which suggests disturbed central carbon metabolism. However, when cultivated in a complex medium, the strain expressing tktA, $aroF^{FBR}$, and aroL produced more tryptophan than the parental strain. These data indicate that additional rate-limiting steps are present in the tryptophan biosynthetic pathway, and the carbon flow to the terminal pathway is strictly regulated. Expressing tktA in E. coli cells appeared to impose a great metabolic burden to the cells as evidenced by retarded cell growth in the defined medium. Recombinant E. coli strains harboring plasmids which carry the tktA gene showed a tendency to segregate their plasmids almost completely within 24h.

• 한국식품저장유통학회지
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• 제23권3호
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• pp.326-334
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• 2016

오미자 열매를 이용하여 기능성물질인 GABA를 강화시킨 오미자 젖산발효음료를 개발하기 위해서 L. plantarum EJ2014에 의한 젖산발효 최적화를 수행하였다. 오미자 열매 추출액을 젖산 발효시킨 경우 발효 2일 동안 생균수 $4.0{\times}10^7CFU/mL$수준을 유지하면서 젖산균 증식이 미비하였지만 영양성분 YE와 MSG를 함께 첨가한 경우 50배 정도 증가된 $2.2{\times}10^9CFU/mL$생균수를 나타내었다. 특히 젖산발효 3일 동안에 대조군, MSG, YE를 각각 첨가군에서 초기 pH 3-4 수준에서 유지되었다. 반면에 YE와 MSG를 함께 첨가한 발효물은 pH가 증가되면서 pH 5.0 이상을 나타내었으며, 초기 산도 1.74%에서 발효 3일에 0.56% 수준으로 감소하였다. 오미자 열매 추출물인 대조군과 2% MSG 또는 0.5% YE만을 첨가한 조건에서는 GABA로 소량 전환되는 것으로 나타났다. 반면에 MSG와 YE를 함께 첨가한 경우 젖산발효 1일째부터 GABA가 생성되면서 3일째에는 MSG 2%를 거의 소진하는 것으로 나타났으며, HPLC 정량분석으로 0.92% GABA 생성이 확인되었다. MSG와 YE함께 첨가한 발효조건에서는 젖산발효 1일째부터 발효물은 붉은 색이 퇴색되면서 황색으로 변화하였으며, 발효 초기에 적색을 나타내는 a값이 15.74에서 발효 후에 5.39로 크게 감소하는 것으로 나타났다. 색, 맛, 향 등을 포함한 전반적인 기호도를 나타낸 관능평가에서 오미자 착즙 원액과 발효물 100%인 실험군에서 점수가 각각 4.50, 4.33을 기록하여 상대적으로 낮은 기호도를 나타낸 반면에 발효물 50% 첨가한 실험군이 6.33으로 가장 높은 기호도 점수를 나타내었다. 오미자 열매 추출액에 오미자 발효물을 50% 첨가함으로서 기호성이 우수하며 고농도 GABA와 probiotic을 함유한 오미자 발효음료의 제조가 가능하였다.

• 생명과학회지
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• 제17권7호통권87호
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• pp.970-975
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• 2007

국내해안의 젓갈과 김치류로부터 86종의 GABA 생산균주를 분리하였다. 분리된 균주들을 Thin layer chromatography를 이용하여 GABA 생성능이 우수한 AML15, AML45-1, AML72의 3종의 균주를 선발하였다. 선별된 3종의 균주의 아미노산 분석 결과 GABA 생성능이 가장 우수한 AML15 균주를 본 실험에 사용하였다. AML15의 분류학적 위치를 규명하기 위하여 16S ribosomal DNA 영역의 부분염기서열 분석을 실시하였다. 165 rDNA 분석결과 Lactobacillus brevis ATCC 367과 99%의 유사도를 나타내어 L. brevis AML15로 명명하였다. MRS 배지에 최종 전환 농도로 설정된 5%(w/v) monosodium glutamic acid를 첨가하고 배지의 초기 pH를 4.0, 5.0과 6.0으로 조정하여 배양한 결과 배지의 초기 pH가 5.0일 때 GABA 생성능이 가장 높게 조사되었다. GABA 생산배지에 GAD 효소활성에 조효소로 작용하는 PLP를 0. 10. 50과 100 ${\mu}M$의 농도로 첨가하여 아미노산 분석결과 PLP를 10${\mu}M$ 첨가하였을 때 10,424 $nM/{\mu}$l의 GABA가생산되었다. PLP를 첨가하지 않았을 때보다 PLP 첨가 후 GABA 생성이 증가됨을 확인할 수 있었다.