• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.294-301
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• 2001

The effects of including glycine and isonicotinic acid hydrazide (INH) in the growth medium (Luria broth, LBG) on the subsequent lysozyme-imduced protoplast formation and transformation efficiency of Corynebacterium glutamicum were studied. The transformation efficiency of C. glutamicum AS019 increased up to 100-fold as the ocncentrationof glycine in the media increased from 0% to 5% (w/v), relative to cells grown in the absence of glycine. The presence of 5 mg/ml INH in the growth medium led to a further 10-fold increase in transformation efficiency. In addition, this transformation protocol was successfully applied to other strains of C. glutamicum. Both chemicals affected the mycolic acid attachment to the cell surface of C. glutamicum, when INH, the relative percentage of fatty acids of AS019 to the total lipids (mycolic acid plus fatty acids) decreased from 76.9% (in LBG) to 72.9% (in LBG-2% glycine) and 66.4% (in LBG-8 mg InG/ml), thereby suggeting that these chemicals also inhibit fatty acid synthesis.

• Journal of Microbiology and Biotechnology
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• 제16권10호
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• pp.1629-1633
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• 2006

Ginsenosides have been regarded as the principal components responsible for the pharmacological and biological activities of ginseng. The transformation of ginsenosides with live lactic acid bacteria transformed ginsenosides Rb2 and Rc into Rd, but the reactions were slow. When the crude enzymes obtained from several lactic acid bacteria were used for transformation, those from Bifidobacterium sp. Int57 exhibited the most potent transforming activity of ginsenosides to compound K. In comparison, a relatively higher level of Rh2 was produced by the enzymes from Lactobacillus delbrueckii and Leuconostoc mesenteroides. These results suggest that it is feasible to develop a specific bioconversion process to obtain specific ginsenosides using the appropriate combination of ginsenoside substrates and specific microbial enzymes.

• 한국식품영양과학회지
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• 제44권12호
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• pp.1912-1917
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• 2015

천연식물에 광범위하게 존재하는 대표적인 페닐프로파노이드 화합물인 caffeic acid에 대해 배 유래의 polyphenol oxidase로 산화반응을 수행하여 상대적으로 높은 pancreatic lipase 저해 활성($IC_{50}$; $161.2{\pm}2.8{\mu}g/mL$)을 확인하였으며, 이는 caffeic acid와 비교하였을 경우 활성이 상승함을 알 수 있었다. Caffeic acid 산화반응물에 대해서 $C_{18}$ 겔을 활용한 column chromatography를 수행하여 4종의 리그난 화합물을 분리하였고, 각 화합물의 화학구조는 NMR 스펙트럼 데이터 해석 및 표품과의 HPLC 직접 비교를 통하여 phellinsin A(2), caffeicinic acid(3), isocaffeicinic acid(4), 7,8-erythro-caffeicin(5)으로 동정하였다. 이들 화합물중 phellinsin A(2)는 $IC_{50}$ 값이 $66.3{\pm}2.6{\mu}M$로 가장 강한 효능을 나타내었으며, 다음으로 caffeic acid 2분자의 산화 결합을 통해 생합성된 caffeicinic acid(3)의 $IC_{50}$ 값이 $109.6{\pm}3.7{\mu}M$의 저해능을 나타내었다. 배에 존재하는 polyphenol 산화효소에 의해 생합성된 caffeic acid 이량체가 pancreatic lipase 저해 활성 물질임을 확인하였으며, 이들 활성은 caffeic acid가 결합 양상에 따른 화합물의 구조에 따라 다름이 시사되었다. 향후 이들 활성물질의 활성 기작에 대한 연구가 필요하며 본 연구 결과는 보다 우수한 pancreatic lipase 저해능을 가지는 새로운 선도화합물 발굴을 위한 기초자료로 이용될 수 있을 뿐만 아니라 항비만 물질의 상업화를 위한 기초자료로 이용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.92-97
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• 1992

Microbial transformation of (-)kaur-l6-en-19-oic acid and (-)pimara-9(1l), 15-dien-19-oic acid from A. koreanum was investigated. Throughout the screening of the capability of metabolizing these bioactive diterpenoids, two microorganisms have chosen among various fungi and streptomycetes tested. Scale-up fermentation with Fusarium oxysporum KCTC 6051 produced two metabolites related to the precursor diterpenoids. The two metabolites were isolated by column chromatography and identified by chemical and spectroscopic methods as $2\beta$, $16\alpha$-dihydroxy kauran-19-oic acid and $16\alpha$-hydroxy kauran-19-oic acid. However any microorganisms capable to transform (-) pimara-9(11), 15-dien-19-oic acid was not screened in this condition.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2870-2872
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• 2014

• Applied Biological Chemistry
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• 제40권3호
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• pp.173-177
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• 1997

Bacillus licheniformis 9945a는 액체배양시 ${\gamma}-poly(glutamic\;acid)$를 균체외로 분비하며, 한천배지에 고체 배양시는 점액질의 군락을 나타낸다. 점액질의 Bacillus속 세균의 형질전환은 그리 순하지 않은 것으로 알려져 있으며, B. licheniformis에서의 trasposon Tn10의 활성여부도 알려져 있지 않다. 그래서 점액질을 분비하지 않는, B. licheniformis의 자연발생적 변이주를 우선 분리하였다. Mini-Tn10을 함유한 plasmid pHV1248을 protoplast transformation법에 준해서 이 변이주에 도입하여 형질전환체를 분리하였다. pHV1248을 함유한 형질전환체를 점액성의 야생형질로 복귀시킨 후에, 가열처리함으로써 무작위 돌연변이를 유도하였다. Arginine, lysine 또는 tryptohan을 생육인자로 요구하는 돌연변이주들이 replica plating method에 의해서 분리되었고, 이 들 영양요구성 변이주는 mini-Tn10이 염색체 DNA상에 삽입됨으로써 생겨났음이 Southern blotting과 DNA-DNA 혼성화 실험으로 증명되었다. 이러한 pHV1248을 이용한 형질전환 및 돌연변이 유도방법은 Bacillus licheniformis 9945a의 다양한 변이체를 얻는데 유용할 것이다.

• Advances in nano research
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• 제12권3호
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• pp.291-300
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• 2022

The behavior of hydrogen species on the surface of the catalyst during the Lewis acid transformation to form Brønsted acid sites over the spherical silica-supported WO_x catalyst was investigated. To understand the structure-activity relationship of Lewis acid transformation and hydrogen bonding interactions, we explore the potential of using the in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) with adsorbed ammonia and hydrogen exposure. From the results of in situ DRIFTS measurements, Lewis acid sites on surface catalysts were transformed into new Brønsted acid sites upon hydrogen exposure. The adsorbed NH₃ on Lewis acid sites migrated to Brønsted acid sites forming NH⁴⁺. The results show that the dissociated H atoms present on the catalyst surface formed new Si-OH hydroxyl species - the new Brønsted acid site. Besides, the isolated Si-O-W species is the key towards H-bond and Si-OH formation. Additionally, the H atoms adsorbed surrounding the Si-O-W species of mono-oxo O=WO₄ and di-oxo (O=)₂WO₂ species, where the Si-O-W species are the main species presented on the Inc-SSP catalysts than that of the IWI-SSP catalysts.

• 약학회지
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• 제32권6호
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• pp.386-393
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• 1988

Chemical transformation of D-glucose to 2-keto-L-gulonic acid and L-ascorbic acid has been examined. D-Sorbitol obtained from D-glucose was microbiologically oxidized to L-sorbose by G. suboxydans in 90% yield. On treatment of L-sorbose with acetone in the presence of sulfuric acid, its diacetonide is obtained in 95% yield. This diacetonide is oxidized to the corresponding acid with nickel chloride-hypochlorite, and the acid is directly transformed to L-ascorbic acid. The over all yield of Vitamin C from D-glucose achieved is 54%.

• 한국환경성돌연변이발암원학회지
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• 제16권1호
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• pp.35-42
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• 1996

Aragonite is one of polymorphs of calcium carbonate of which main form is calcite. We found that white precipitate is formed in much amount by boiling underwater of Inchon, Korea and confirmed that it is aragonite. This study is to evaluate the dimensional characteristics, solubility, acid resistance of aragonite and the cytotoxicity, cell division disturbance and cell transforming ability of it on BALB/3T3 cells. The results are as follows: Lengths of the aragonite were reduced to the 72.7% and 22.7% respectively after 5 months and 7 months of intrapleurai injection to the Sprague-Dawley rat. Strong acid such as 1M HCl dissolved the aragonite instantly but weaker acid pH 2.0 or more could not dissolved aragonite easily. The result of cell growth inhibition showed that cell numbers were decreased as log-doses of treatment of the aragonite were increased 24 hours, 48 hours, and 72 hours later. Cell plating efficiency after the aragonite treatment also showed dose-dependent decrease. Multinuclear giant cell formation was increased in the aragonite treated cells until ID$_{50}$ and after the dose the multinucleate cells were decreased, but remained much higher than negative control cells. Morphological transformation assay showed that the aragonite did not induce transformation in all treated doses.

• 한국약용작물학회지
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• 제21권5호
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• pp.401-414
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• 2013

Ginsenoside Rg3 (G-Rg3) contained only in red ginseng has been found to show various pharmacological effects such as an anticancer, antiangiogenetic, antimetastastic, liver protective, neuroprotective immunomodulating, vasorelaxative, antidiabetic, insulin secretion promoting and antioxidant activities. It is well known that G-Rg3 could be divided into 20(R)-Rg3 and 20(S)-Rg3 according to the hydroxyl group attached to C-20 of aglycone, whose structural characteristics show different pharmacological activities. It has been reported that G-Rg3 is metabolized to G-Rh2 and protopanaxadiol by the conditions of the gastric acid or intestinal bacteria, thereby these metabolites could be absorbed, suggesting its absolute bioavailability (2.63%) to be very low. Therefore, we reviewed the chemical, physical and biological transformation methods for the production on a large scale of G-Rg3 with various pharmacological effects. We also examined the influence of acid and heat treatment-induced potentials on for the preparation method of higher G-Rg3 content in ginseng and ginseng products. Futhermore, the microbial and enzymatic bio-conversion technologies could be more efficient in terms of high selectivity, efficiency and productivity. The present review discusses the available technologies for G-Rg3 production on a large scale using chemical and biological transformation.