• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.667-667
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• 2000

Pseudomonas sp. BK7, an alkalophile, displayed the highest growth and protease activity when grown in a fermenter which was controlled at a pH level of 9.0, and the enzyme production was significantly enganced by the increase of agitation speed. Two formas of alkaline proteases (BK7-1 and BK7-2) were fractionated and purified to near homogeneity. Protease BK7-1 was purified through CM-Sepharose CL-6B and Sephadex G-75 column chromatographies, and Protease BK7-2 was purified through CM-Sepharose CL-6B and Sephadex G-75 column chromatographies, and Protease BK7-2 was purified through CM-Sepharose CL-6B, DEAE-Sepharose, and Sephadex G-75 column chromatographies. The molecular weights of proteases BK7-1 and BK7-2 determined by gel filtration chromatography were 20,700 and 40,800, respectively. The $K_m$ value, isoelectric point, and optimum pH of protease BK7-1 were 2.55 mg/ml, 11.0 and 11.0, respectively, whereas those of protease BK7-2 were 1.57 mg/ml, 7.2, and 10.0, respectively. Both protease were practically stable in the pH range of 5-11. The optimum temperatures for the activities of both protease BK7-1 and BK7-2 were 50℃ and 45℃, respectively. About 56% of the original protease BK7-2 activity remained after being treated at 50℃ for 30 min but protease BK7-1 was rapidly inactivated at above 25℃. Both proteases were completely inhibited by phenylmethane sulfonyl fluoride, a serine protease inhibitor. Protease BK7-2 was stable against EDTA, EGTA, STP, and detergents such as SDS and LAS, whereas protease BK7-1 was found to be unstable.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.677-684
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• 2000

Pseudomonas sp. BK7, an alkalophile, displayed the highest growth and protease activity when grown in a fermenter which was controlled at a pH level of 9.0, and the enzyme production was significantly enhanced by the increase of agitation speed. Two forms of alkaline proteases (BK7-1 and BK7-2) were fractionated and purified to near homogeneity. Protease BK7-1 was purified through CM-Sepharose CL-6B and Sephadex G-75 column chromatographies, and Protease BK7-2 was purified through CM-Sepharose CL-6B, DEAE-Sepharose, and Sephadex G-75 column chromatographies. The molecular weights of proteases BK7-1 and BK7-2 determined by gel filtration chromatography were 20,700 and 40,800, respectively. The $K_m$ value, isoelectric point, and optimum pH of protease BK7-1 were 2.55 mg/ml, 11.0, and 11.0, respectively, whereas those of protease BK7-2 were 1.57 mg/ml, 7.2, and 10.0, respectively. Both proteases were practically stable in the pH range of 5-11. The optimum temperatures for the activities of both protease BK7-1 and BK7-2 were $50^{\circ}C$ and $45^{\circ}C$, respectively. About 56% of the original protease BK7-2 activity remained after being treated at $50^{\circ}C$ for 30 min but protease BK7-1 was rapidly inactivated at above $25^{\circ}C$. Both proteases were completely inhibited by phenylmethane sulfonyl fluoride, a serine protease inhibitor. Protease BK7-2 was stable against EDTA, EGTA, STP, and detergents such as SDS and LAS, whereas protease BK7-1 was found to be unstable.

• 한국식품영양과학회지
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• 제25권5호
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• pp.741-746
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• 1996

대나무잎 추출물을 대상으로 이들을 여러 용매별로 분획하여 동치미 발효에 관여하는 젖산균에 대해 항균활성을 조사하였다. 동치미 담금액 중의 총 균수는 젖산 균수와 발효기간별로 대체적으로 비슷한 양상을 나타내었고 발효 8일째 (equation omitted) a $10^{7}$ CFU/m1로 최고 수치를 나타내었다. 동치미에서 분리한 젖산균을 동정한 결과, BK-02, BK-07 및 BK-22 균주는 Leuconostoc species 로, BK-05와 BK-08 균주는 Lactobaciilus species로, BK-15 균주는 Streptococcus species로 각각 확인되었다. 대나무잎(이대)의 70% ethanol추출물은 BK-02, BK-07, BK-15및 BK-22 균주들에 대해 항균활성을 나타내었으며 특히, BK-22 균주에서 가장 효과가 좋았다. 각 분획별 항균활성은 BK-22 균주가 70% ethanol 분획에서, BK-7 균주가 diethyl ether 분획에서 강하게 나타났으며, 이 두 추출물이 대부분의 분리 균주들에 대해서 항균활성을 나타내었다.

• 미생물학회지
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• 제51권2호
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• pp.156-168
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• 2015

Lactobacillus acidophilus BK13과 Lactobacillus paracasei BK57 균주로부터 얻은 세포, 배양상등액 및 박테리오신 용액의 anti-Helicobacter pylori 활성과 위장상피세포에 대한 세포독성을 평가하였다. 실험균주를 MRS 배지 상에서 30시간 배양한 결과, L. acidophilus BK57 ($126.8{\pm}7.9mM$) 보다 L. paracasei BK57 ($155.9{\pm}7.9mM$)가 더 많은 양의 유산을 생산하였다. 또한, BK13 균주의 최대 박테리오신 활성(128 AU/ml)은 $37^{\circ}C$에서 30시간 배양 후 관찰되었으나, 이는 BK57의 활성(256 AU/ml) 보다는 낮았다. BK13 및 BK57 균주의 살아있는 세포를 H. pylori와 혼합 배양한 결과, 유산균의 초기균수에 의존하여 H. pylori의 저해효과가 나타났다. 게다가 BK13과 BK57로부터 얻은 배양상등액과 박테리오신은 H. pylori의 성장을 억제할 뿐만 아니라 위장상피세포에 대한 부착력과 urease 활성도 저해하였다. 한편, 이러한 균주들이 생산한 유산은 위암세포에 대한 세포독성 효과가 대조구보다 유의한 수준으로 높게 나타났다. 따라서 BK13과 BK57 균주의 항균물질은 위장질환의 원인균인 H. pylori를 저해시키는데 효과적이므로 이들 유산균은 H. pylori 감염으로부터 위장을 보호하는데 유용할 것으로 사료된다.

• 한국레이저가공학회지
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• 제15권3호
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• pp.16-19
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• 2012

We have successfully formed brown colored patterns inside of a transparent borosilicate glass generally known as BK7, laying the focus of near infrared Ti: sapphire femtosecond laser beam in the bulk BK7 glass. It is important to keep the laser power well below the damage threshold of BK7 in forming the color center. According to the low laser power, there was no laser induced mechanical damage such as cracks or threads in the color formed area. From the absorbance spectrum and its gaussian fitting, we found the band gap of BK7, 4.21eV, and three absorption edges.

• 한국생산제조학회지
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• 제21권1호
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• pp.85-89
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• 2012

Conventional grinding of BK7 glass will normally result in brittle fracture at the surface, generating severe sub-surface damage and poor surface finish. The precision grinding of BK7 glass in parallel grinding modes has been investigated. Grinding process, maximum chip thickness, ductile/brittle regime, surface roughness and sub-surface damage have been addressed. Special attention has been given to the condition for generating a ductile mode response on the ground surface. Experiments reveal that the level of surface roughness and depth of sub-surface damage vary differently for different condition. This study gives an indication of the strategy to follow to achieve high quality ground surfaces on brittle materials.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.209-210
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• 2006

We have successfully termed brown colored patterns inside of a transparent borosilicate glass generally known as BK7, laying the focus of near infrared Ti: sapphire femtosecond laser beam in the bulk BK7 glass. It is important to keep the laser power well below the damage threshold of BK7 in forming the color center. Thanks to the low laser power, there was no laser induced mechanical damage such as cracks or threads in the color formed area. From the absorbance spectrum and its gaussian fitting, we found the band gap of BK7, 4.21eV, and three absorption edges.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.921-924
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• 2003

Homochiral (-)-pipecolaldehyde 6 from D-glucono- δ-lactone underwent a highly diastereoselective addition upon treatment with vinylmagnesium bromide. Treatment with vinylmagnesium bromide produced antiaminoalcohol 7a which was easily converted into the synthesis of 1,6-diepicastanospermine 2.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2009년도 심포지엄 및 춘계학술발표회
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• pp.205-206
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• 2009

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2012년도 심포지엄 및 춘계학술발표회
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• pp.173-174
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• 2012