• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.2000-2003
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• 2006

A gene (GenBank AF096282) coding for a $\alpha$-glucosidase (TcaAG, EC 3.2.1.20) from Thermus caldophilus GK24 was expressed in Saccharomyces cerevisiae, a generally recognized as safe (GRAS) host. The thermostable $\alpha$-glucosidase was produced inside of the GRAS host at 0.04 unit/mg-dry cell by the constitutively expressing ADH1 promoter and at 1.2 unit/mg-dry cell by the inductively expressing GALl0 promoter, respectively. No $\alpha$-glucosidase activities were found in the medium when the MF-alpha signal sequence from S. cerevisiae or $\alpha$-amylase signal sequence from Aspergillus oryzae were fused before the $\alpha$-glucosidase gene for the secretion.

• 한국전자파학회지:전자파기술
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• 제20권2호
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• pp.59-67
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• 2009

본고를 통해 초고주파 이론과 공학 분야는 물론 물리학, 재료공학의 기초 학문 분야에서도 지대한 관심을 모으고 있는 Metamaterial(MTM) 구조에 대해 조명하고자 한다. 먼저 MTM의 핵심이라고 할 수 있는 Left-Handedness(LH) 왼손 전파 법칙과 LH 발생 재질인 Double Negative(DNG) 재질에서의 전파 특성을 상대 유전율과 상대 투자율 평면에서 확인하고, 일반 매질인 Double Positive(DPS)형인 오른손 전파 법칙 Right-Handedness(=RH) 매질과의 결합(Composite Right-and Left-Hnaded=CRLH)에서 얻어지는 특징들을 살펴본다. 특히 DPS와 DNC의 결합에서 얻을 수 있는 음의 공진과 0차 공진(Zero-Order Resonance)을 언급하고 ZOR을 응용한 RF 부품의 소형화와 특성 개선사례를 소개한다. 또한, 안테나와 전자파 산란 특성에 MTM의 특수한 성질을 이용하여, 크기를 줄이거나 표면파를 억제하거나 혹은 방사 개구를 확대 또는 렌즈 특성을 얻어낸 사례도 언급된다 그리고 LH 특성은 아니지만 MTM 계열인 ENG(Epsilon Negative), MNG(Mu Negative), ENZ(Epsilon Near Zero)를 응용한 예들을 보이고, MTM 관점에서 FSS(Frequency Selective Surface )의 특성을 논의하고, 그간에 발표된 대표적 MTM 연구 결과에 대한 소개를 마치고자 한다.

• 한국식품위생안전성학회지
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• 제25권1호
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• pp.59-64
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• 2010

본 연구에서는 식초와 주정 및 아스코르빈산의 첨가량을 달리하여 제조한 생강다대기 (MG)를 $30^{\circ}C$에서 저장하면서 첨가물이 저장 중 품질특성에 미치는 영향을 살펴보았다. 생강다대기의 저장 중 색도의 경우 T-I 처리구 색도값이 다른 첨가구와 비교하여 높은 값을 보여주었고, 총 색차인 ${\Delta}E$는 T-III 처리구에서 저장 28일 경과 후에도 색도 변화가 가장 적은 것으로 나타났다. 생강다대기의 일반세균수를 측정한 결과, 저장 초기 무첨가구(T-0)에서 일반세균수가 $5.37{\times}10^7\;CFU/g$ 이었으나, MG-처리구의 초기 일반세균수가 T-0와 비교하여 4 log 이상 감소하는 경향을 보였다. 이는 저장기간 중 미생물의 증식없이 초기 일반세균수를 유지하는 경향을 보여 첨가물의 미생물 증식억제 효과를 확인할 수 있었다. 생강다대기의 관능평가를 실시한 결과, T-0와 MG-처리구간의 향기에 대한 강도 평가에 있어서 유의적인 차이를 보이지 않았다(p < 0.05). 전자코 분석장치에 의한 생강다대기의 향기성분 분석 결과, 초기치 생강다대기 향은 T-0에 비하여 T-I, T-II, T-III 처리구의 향기가 좀 더 강하게 인지되었으나, 저장 중 향기성분의 변화는 첨가물의 종류나 첨가량에 관계없이 저장온도 $30^{\circ}C$에서도 안정적으로 유지되는 것으로 나타났다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.375-379
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• 2002

Methyl mercaptan oxidase was successfully induced in Thiobacillus thioparus TK-m using methyl mercaptan gas, and was purified for the detection of mercaptans. The purification procedure Involved a DEAE (diethylaminoethyl) -Sephacel, or Superose 12, column chromatography with recovery yields of 47.5 and 48.5%, and specific activities of 374 and 1240.8 units/mg-protein, respectively, The molecular weight of the purified methyl mercaptan oxidase was 66.1kDa, as determined by SDS-PAGE. The extract, from gel filtration chromatography oxidizes methyl mercaptan, producing formaldehyde, which can be easily detected by the purpald-coloring method. The optimized temperature for activity was found to be at 55$\^{C}$. This enzyme was inhibited by both NH$_4$Cl and (NH$_4$)$_2$SO$_4$, but was unaffected by either KCl or NaCl at less than 200 mM. With K$_2$SO$_4$, the activity decreased at 20 mM, but recovered at 150 mM. In the presence of methanol, full activity was maintained, but decreased in the presence of glycerin, ethanol and acetone 43, 78 and 75%, respectively.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.230-234
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• 2006

In this study, we describe a one-step chemoenzymatic reaction for the production of natural blue pigments, in which the geniposide from Gardenia extracts is transformed by glycosidases to genipin. Genipin is then allowed to react with amino acids, thereby generating a natural blue pigment. The ${\beta}-glycosidases$, most notably Isolase (a variant of ${\beta}-glucanase$), recombinant ${\beta}-glycosidases$, Cellulase T, and amylases, were shown to hydrolyze geniposide to produce the desired pigments, whereas the ${\alpha}-glycosidases$ did not. Among the 20 tested amino acids, glycine and tyrosine were associated with the highest dye production yields. The optimal molar ratio of geniposide to glycine, two reactants relevant to pigment production, was unity The natural blue pigments produced in this study were used to dye cotton, silk, and wool. The color yields of the pigments were determined to be significantly higher than those of other natural dyes. Furthermore, the color fastness properties of these dyes were fairly good, even in the absence of mordant.

• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.1983-1990
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• 2007

Antidiabetic effects of a novel microbial biopolymer (PGB) 1 excreted from new Enterobacter sp. BL-2 were tested in the db/db mice. The animals were divided into normal control, rosiglitazone (0.005%, wt/wt), low PGB1 (0.1%, wt/wt), and high PGB1 (0.25%, wt/wt) groups. After 5 weeks, the blood glucose levels of high PGB1 and rosiglitazone supplemented groups were significantly lower than those of the control group. In hepatic glucose metabolic enzyme activities, the glucokinase activities of PGB1 supplemented groups were significantly higher than the control group, whereas the PEPCK activities were significantly lower. The plasma insulin and hepatic glycogen levels of the low and high PGB1 supplemented groups were significantly higher compared with the control group. Specifically, the insulin and glycogen increases were dose-responsive to PGB1 supplement. PGB1 supplement did not affect the IPGTT and IPITT compared with the control group; however, rosiglitazone significantly improved IPITT. High PGB1 and rosiglitazone supplementation preserved the appearance of islets and insulin-positive cells in immunohistochemical photographs of the pancreas compared with the control group. These results demonstrated that high PGB1 (0.25% in the diet) supplementation seemingly contributes to preventing the onset and progression of type 2 diabetes by stimulating insulin secretion and enhancing the hepatic glucose metabolic enzyme activities.

• Parasites, Hosts and Diseases
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• 제48권2호
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• pp.151-155
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• 2010

Allergen extracts from dust mites and cockroaches commonly found in Korean homes were used to evaluate their enzymatic activity as they are believed to influence allergenicity. Allergen extracts were prepared from 3 dust mite species (Dermatophagoides farinae, D. pteronyssinus, and Tyrophagus putrescentiae) and 3 cockroach species (Blattella germanica, Periplaneta americana, and P. fuliginosa) maintained in the Korea National Arthropods of Medical Importance Resource Bank. Proteins were extracted in PBS after homogenization using liquid nitrogen. The activities of various enzymes were investigated using the API Zym system. No significant difference in phosphatase, lipase, or glycosidase activity was observed among the 6 allergen extracts, but much difference was observed in protease activity. Protease activity was assessed in more detail by gelatin zymography and the EnzChek assay. Extract from T. putrescentiae showed the highest protease activity, followed by those of the cockroach extracts. Extracts from D. farinae and D. pteronyssinus showed only weak protease activity. Gelatinolytic activity was detected mainly in a 30-kDa protein in D. farinae, a 28-kDa protein in D. pteronyssinus, a > 26-kDa protein in T. putrescentiae, a > 20-kDa protein in B. germanica, and a > 23-kDa protein in P. americana and P. fuliginosa. The information on various enzymatic activities obtained in this study may be useful for future studies. In particular, the strong protease activity found in cockroach extracts could contribute to sensitization to cockroach allergens, which is known to be associated with the development of asthma.

• Asian-Australasian Journal of Animal Sciences
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• 제11권3호
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• pp.249-254
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• 1998

Two experiments were conducted to evaluate the effects of processing of barley on the growth performance and ileal and fecal digestibility of growing pigs. In Exp. 1, a total of 20 cannulated pigs (10.80 kg BW) were allotted to four treatments. Treatments were coarse ground barley as a control (CON), finely ground barley (FINE), extruded barley (EXT) and enzyme supplemented coarse ground barley (ENZ). In Exp. 2, a total of 100 growing pigs (36.50 kg BW) were allocated to the same treatments in completely randomized block design based on sex and body weight. In the first trial, pigs fed extruded barley showed significantly higher crude protein digestibility over pigs fed finely ground barley (p < 0.05). Pigs fed finely ground barley generally showed lower nutrients digestibility. Extrusion and ${\beta}$-glucanase supplementation showed a trend to improve nutrients digestibility. However, fine grinding rather reduced nutrients digestibility. The similar trend was found in the digestibility of essential amino acids. Fine grinding of barley significantly reduced amino acids digestibility. Extrusion and enzyme supplementation were found to improve amino acids digestibility of barley in growing pigs. In the growth trial, pigs fed extruded barley grew significantly faster than any other processed barley fed pigs. And extrusion of barley significantly improved feed/gain of pigs (p < 0.05). Fine grinding of barley and enzyme supplementation did not improve growth performance of pigs. In conclusion, fine grinding and enzyme supplementation does not appear to be an economical feed processing for growing pigs when barley is employed in the diets, while extrusion can be recommended as an effective feed processing technique for barley.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.35-49
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• 2003

In this study, in an attempt to search for functional cosmetic ingredients from higher fungal, we have produced exopolysaccharides (GF-l, approximately carbohydrate 75％, protein 25％) and polysaccharide (GF-2) of mycelium extract, by submerged culture of Grifolafrondosa. For applications in anti-aging cosmetic field, we investigated the diverse biological activities. Antioxidant activity and inhibition of Matrixmetalloproteinases (MMPs) were investigated enzymatic assays by measuring the superoxide scavenging activity using xanthine-xanthine oxidase system and the proteolytic activity of MMPs using EnzChek Collagenase/Gelatinase kits, respectively. GF-l polysacchairde showed inhibition of superoxide radical by 90％ at a concentration of 0.2％ (w/v) and inhibition of collagenase by 45％ at 0.2％ (w/v). GF-2 polysaccharide of mycelium extract also exhibited good antioxidant activity. However, MMPs inhibition activity was relatively lower level compared to GF-l polysaccharides. The treatment of human dermal fibroblast (HDF) with GF-l and GF-2 polysaccharides increased the proliferation of fibroblast by approximately 23-25％ at a concentration of 0.5％ (w/v), also showed collagen synthesis increase in HDF by about 50％ at 0.5％ (w/v) compared to that of untreated control. We also report the moisturizing effects of polysaccharides in cosmetic products (O/W emulation) and its own ingredient, in vitro and in vivo. The GF-1 polysaccharide showed higher moisturizing ability than sodium hyaluronate, which is the most commonly used moisturizers ingredient. These results suggest the GF-l polysaccharide, protein-bound polysaccharide, may be used as an ingredient for new moisturizing and anti-aging cosmeceuticals.

• KSBB Journal
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• 제21권4호
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• pp.298-301
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• 2006

트레할로스 합성효소(trehalose synthase)의 효율적인 생산을 위하여, 5 종류의 plasmid를 형질전환 시킨 재조합 E. coli를 이용하여 균체생산량과 효소발현량을 비교하였다. Trehalose synthase의 활성은 fusion partner를 이용한 system 에서는 활성이 나타나지 않았으며, IPTG 유도 발현 시스템보다 항시적 발현 시스템을 사용하는 E. coli K12/pHCETS에서 가장 높은 활성을 나타내었다. 선별된 재조합 E. coli K12/pHCETS를 사용하여 회분식 및 유가배양을 수행하였으며, 유가식 배양의 경우 균체논도는 20 g/L, 최종 trehalose synthase 활성은 13.7 U/ml을 나타내었다. 이러한 결과는 트레할로스 생산을 위한 trehalose synthase가 재조합 E. coli의 발효에 의해 경제적으로 생산되어질 수 있다는 가능성을 보여 주었다.