• Journal of Microbiology and Biotechnology
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• 제28권8호
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• pp.1260-1269
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• 2018

Production of good Koji primarily depends upon the selection of substrate materials and fermentative microflora, which together influence the characteristic flavor and aroma. Herein, we performed comparative metabolomic analyses of volatile organic compounds (VOCs) and primary metabolites for Koji samples fermented individually with Bacillus amyloliquefaciens and Aspergillus oryzae. The VOCs and primary metabolites were analyzed using headspace solid phase microextraction (HS-SPME) followed by gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). In particular, alcohols, ketones, and furans were mainly detected in Bacillus-fermented Koji (Bacillus Koji, BK), potentially due to the increased levels of lipid oxidation. A cheesy and rancid flavor was characteristic of Bacillus Koji, which is attributable to high content of typical 'off-flavor' compounds. Furthermore, the umami taste engendered by 2-methoxyphenol, (E,E)-2,4-decadienal, and glutamic acid was primarily detected in Bacillus Koji. Alternatively, malty flavor compounds (2-methylpropanal, 2-methylbutanal, 3-methylbutanal) and sweet flavor compounds (monosaccharides and maltol) were relatively abundant in Aspergillus-fermented Koji (Aspergillus Koji, AK). Hence, we argue that the VOC profile of Koji is largely determined by the rational choice of inocula, which modifies the primary metabolomes in Koji substrates, potentially shaping its volatolome as well as the aroma characteristics.

• 셀메드
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• 제2권2호
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• pp.20.1-20.5
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• 2012

$Gynura$ $segetum$ (Lour.) Merr. ($Compositae$) is a well recognized medicinal plant in Indonesia and Malaysia. It is believed to have an anticoagulant effect and is used in treating snake-bites, inflammations and other skin afflictions. This study was carried out to evaluate the antimicrobial effects of $Gynura$ $segetum$ leaves extracts and its fractions. The chemical compositions of the active extracts were also determined. The antimicrobial activities of different solvent extracts of leaves of $Gynura$ $segetum$ were evaluated using the agar well-diffusion method. The Minimum Inhibitory Concentration (MIC) of the active subfractions was determined by the tube dilution method. Gas Chromatography-mass spectrometry (GC-MS) analysis was carried out to identify the chemical compositions of the active extracts. The ethyl acetate fraction and its subfraction E4 performed potent antimicrobial activities and fifteen known chemical constituents were identified by GCMS analysis as 4-vinylphenol, 1-tetradecene, phenol, 2,4-bis(1,1-dimethylethyl), 1-hexadecene, E-15-heptadecenal, hexadecanoic acid, 1,2-benzenedicarboxylic acid, dibutyl ester, 1-docosene, octadecanoic acid, 1-eicosene, cyclotetracosane, 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl)ester, butanedioic acid, monomethyl ester, niacin and 4-hydroxy-benzoic acid. The results of this study suggested a connection between the antimicrobial activities and the chemical structures. The plant may be used as a potential source for antimicrobial agents.

• Toxicological Research
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• 제26권2호
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• pp.149-155
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• 2010

The pesticide trichlorfon is readily degraded under experimental conditions to dichlorvos. A method has therefore been developed by which residues of trichlorfon in milk are determined as dichlorvos, using gas chromatography with ${\mu}$-electron capture detection. The identification of dichlorvos was confirmed by mass spectrometry. Milk was extracted with acetonitrile followed by centrifugation, freezing lipid filtration, and partitioning into dichloromethane. The residue after partitioning of dichloromethane was dissolved in ethyl acetate for gas chromatography. Recovery concentration was determined at 0.5, 1.0, and 2.0 of times the maximum permitted residue limits (MRLs) for trichlorfon in milk. The average recoveries (n = 6) ranged from 92.4 to 103.6%. The repeatability of the measurements was expressed as relative standard deviations (RSDs) ranging from 3.6%, to 6.7%. Limit of detection (LOD) and limit of quantification (LOQ) were 3.7 and $11.1{\mu}g/l$, respectively. The accuracy and precision (expressed as RSD) were estimated at concentrations from 25 to $250{\mu}g/l$. The intra- and inter-day accuracy (n = 6) ranged from 89.2% to 91% and 91.3% to 96.3%, respectively. The intra- and inter-day precisions were lower than 8%. The developed method was applied to determine trichlorfon in real samples collected from the seven major cities in the Republic of Korea. No residual trichlorfon was detected in any samples.

• Journal of Microbiology and Biotechnology
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• 제33권6호
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• pp.724-735
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• 2023

NdgR, a global regulator in soil-dwelling and antibiotic-producing Streptomyces, is known to regulate branched-chain amino acid metabolism by binding to the upstream region of synthetic genes. However, its numerous and complex roles are not yet fully understood. To more fully reveal the function of NdgR, phospholipid fatty acid (PLFA) analysis with gas chromatography-mass spectrometry (GC-MS) was used to assess the effects of an ndgR deletion mutant of Streptomyces coelicolor. The deletion of ndgR was found to decrease the levels of isoleucine- and leucine-related fatty acids but increase those of valine-related fatty acids. Furthermore, the defects in leucine and isoleucine metabolism caused by the deletion impaired the growth of Streptomyces at low temperatures. Supplementation of leucine and isoleucine, however, could complement this defect under cold shock condition. NdgR was thus shown to be involved in the control of branched-chain amino acids and consequently affected the membrane fatty acid composition in Streptomyces. While isoleucine and valine could be synthesized by the same enzymes (IlvB/N, IlvC, IlvD, and IlvE), ndgR deletion did not affect them in the same way. This suggests that NdgR is involved in the upper isoleucine and valine pathways, or that its control over them differs in some respect.

• 생명과학회지
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• 제18권2호
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• pp.167-174
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• 2008

치아우식균으로 알려져 있는 Streptococcus mutans에 대한 초피(Zanthoxylum piperitum)의 항균활성을 조사하기 위해, 뿌리, 줄기, 잎, 과피, 그리고 종자 부분을 methanol, ethyl acetate, hexane, methylene chloride등의 유기용매로 추출한 후 그 추출물의 항균활성을 $1{\sim}3$ mg/disc 농도범위에서 측정하였다. 그 결과, 종자의 경우만 활성이 나타났으며 특히 methylene chloride 추출물에서 비교적 높은 항균활성이 확인되었다. 초피종자의 항균활성이 종자의 정유성분을 추출할 경우에도 회수되는지를 조사하기 위해 초피종자 및 초피과피로부터 정유성분을 추출하고 이들의 S. mutans에 대한 항균활성을 측정하였다. 이때 두 정유성분 모두는 종자의 methylene chloride 추출물 보다 더 강한 항균효과를 보였다. 이 정유성분들의 S. mutans에 대한 최소저해농도(MIC)를 액체배양으로 측정한 결과, 초피종자 정유성분의 MIC는 0.3 mg/ml 로, 또한 초피과피 정유성분의 MIC는 4 mg/ml로 나타났다. S. mutans에 대한 항균활성이 가장 높게 나타난 종자의 정유성분을 박층크로마토그래피 방법으로 7가지 분획으로 나누어 그 항균효과를 서로 비교 조사한 결과, 다섯번째 분획(CS-SD-E)의 항균활성이 다른 분획들의 항균활성에 비해 상대적으로 높았으나, 분획 전의 정유성분에 비해서는 모두 항균활성이 낮았다. 초피종자의 항균활성성분을 조사하기 위해, 초피종자의 methylene chloride 추출물과 초피종자 정유성분을 GC-MS로 비교 분석하였다. 초피종자의 methylene chloride 추출물에서는 S. mutans에 대한 항균활성이 이미 보고된 물질로서 carvacrol (0.24%), ${\beta}$-caryphyllene (1.72%), ${\alpha}$-humulene (0.88%)등이 검출되었고, 초피종자 정유성분에서는 sabinene (1.57%), linalool (1.55%), citronellal (13.67%), terpinene-4-ol (0.45%), citronellol (3.69%), geraniol (0.9%), linalyl acetate (1.35%), ${\beta}$-caryophyllene (1.35%), ${\alpha}$-humulene (0.7818%) 및 ${\delta}$-cadinene (0.67%) 등이 S. mutans에 대한 항균활성이 보고된바 있는 물질로서 확인되었다. 이상의 연구결과는 초피종자가 S. mutans에 대해 항균활성을 가지며, 수증기 증류를 통해 확보하는 종자의 정유성분 회수가 이러한 항균물질을 추출하는 효과적인 방법임을 시사한다. 아울러 본 연구결과는 초피종자 유래의 정유성분이 S. mutans에 의해 발생하는 치아우식의 예방에 활용될 수 있음을 시사한다.

• 한국식품과학회지
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• 제48권1호
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• pp.1-8
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• 2016

한국에서 생산 및 유통되고 있는 서로 다른 밀원의 45개 벌꿀(아카시아꿀 15, 잡화꿀 15, 밤꿀 10, 사양꿀 5)을 대상으로, 단당류, 이당류 그리고 삼당류를 TMSO 및 TMSMe 유도체화를 만들어 GC/MS를 이용하여 분석하였다. 아카시아꿀, 잡화꿀, 밤꿀과 사양꿀에서 전화당의 총 함량은 각각 $69.3{\pm}2.86$, $66.4{\pm}3.28$, $62.4{\pm}2.24$와 $68.0{\pm}2.32%$였고, F/G 비는 1.61, 1.46, 1.90와 1.13이었다. 벌꿀시료에서 이당류는 약14종을 분리하였으며, 이전의 연구에서 보고된 cellobisoe와 melebiose는 모든 벌꿀시료에서 검출되지 않았다. 주요 이당류로는 turanose, maltulose, maltose, trehalulose, kojibiose, isomaltose, nigerose였으며, 꽃꿀에서 미량으로 존재하는 이당류로는 sucrose, ${\alpha}$-trehalose, ${\alpha},{\beta}$-trehalose, laminaribiose, palatinose, gentibiose 등으로 나타났다. 이당류의 총 함량은 maltulose, turanose, trehalulose의 함량이 높은 밤꿀에서 $14.2{\pm}2.43%$로 가장 높았으며, 아카시아 꿀에서 상대적으로 낮은 $8.79{\pm}1.76%$였다. 밀원별 벌꿀에서 7종류의 삼당류를 정량분석하였으며, 그 중 erlose는 사양꿀에서 $4.59{\pm}1.28%$로 가장 높았으며, 꽃꿀에서는 0.79-1.75%의 함량분포를 나타내었다.. 이당류와 삼당류의 총 함량은 maltulose와 turanose, trehalulose, isomaltose 등의 함량이 높게 나타난 밤꿀에서 $16.0{\pm}2.03%$로 가장 높았으며, 아카시아, 잡화꿀과 사양꿀에서는 각각 $9.70{\pm}1.75%$, $11.5{\pm}3.07%$와 $15.1{\pm}3.19%$의 평균함량 분포를 보였다.

• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.386-393
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• 2000

Recent research on the fatty acyl chains in the membrane lipids in Sarcina ventriculi has shown that unusually long chain bifunctional fatty acyl components are the major components of the total lipid. However, these studies did not yield any information on the complete structures of the lipid species containing these fatty acids. In this study, the structures of a new family of glucolipids containing bifunctional acyl chains are described. These structures were determined using NMR(Nuclear Magnetic Resonance) Spectroscopy, GC (Gas Chromatography)/MS (Mass Spectrometry), FTIR (Fourier Transform Infrared) spectroscopy, and FAB (Fast Atom Bombardment) mass spectrometric studies. One of the major bifunctional acyl components of the $\alpha$-glucolipids was an $\omega$-formylmethyl ester indicating the presence of plasmalogen. The general structure of the lipid components was one in which the two head groups were separated by a membrane-spanning acyl species. One head group component is a glycerol moiety of each head group, and the other is a glyceryl clucoside. Two regular chain fatty acids, one on the glycerol moiety of each head group, are also present and meet in the middle of the membrane, roughly equidistant from each head group.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.497-502
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• 2008

The essential oil from the cones of Pinus koraiensis was prepared after removing the seeds, and its chemical composition analyzed using gas chromatography-mass spectrometry (GC-MS). Hydrodistillation of the P. koraiensis cones yielded 1.07% (v/w) of essential oil, which was almost three times the amount of essential oil extracted from the needles of the same plant. Moreover, the antimicrobial activities of the oil against the growth of Gram-positive bacteria, Gram-negative bacteria, and fungi were evaluated using the agar disc diffusion method and broth microdilution method. Eighty-seven components, comprising about 96.8% of the total oil, were identified. The most abundant oil components were limonene (27.90%), ${\alpha}$-pinene (23.89%), ${\beta}$-pinene (12.02%), 3-carene(4.95%), ${\beta}$-myrcene (4.53%), isolongifolene (3.35%), (-)-bornyl acetate (2.02%), caryophyllene (1.71%), and camphene (1.54%). The essential oil was confirmed to have significant antimicrobial activities, especially against pathogenic fungal strains such as Candida glabrata YFCC 062 and Cryptococcus neoformans B 42419. Therefore, the present results indicate that the essential oil from the cones of Pinus koraiensis can be used in various ways as a nontoxic and environmentally friendly disinfectant.

• 임산에너지
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• 제20권1호
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• pp.35-41
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• 2001

리그닌 모델화합물 Ⅰ-Ⅳ의 시료를 315℃에서 열분해 시킨 결과, 리그닌 모델호합물 Ⅰ, Ⅱ의 열분해에서는 guaiacol이 0.47mol, DMP가 0.57mol로, DMAP는 0.12와 0.23mol로 각각 생성되었으며, 리그닌 모델화합물 Ⅲ, Ⅳ의 열분해에서는 guaiacol의 생성이 0.26mol, DMP가 0.30mol로 TMAP는 0.09mol 과 0.15mol이 각각 생성되었다. 리그닌 모델화합물 열분해 메커니즘으로서는 우선 탈수되고, 이어서 β-O-4 결합이 개열되어 guaiacol, DMP, DMAP와 TMAP가 생성되는 것을 알 수 있었다.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1086-1091
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• 2008

The antioxidant activities of the extracts of dangyuja (Citrus grandis Osbeck) leaves were evaluated. The highest phenolic content was obtained from the ethyl acetate fraction (EF) (202.1$\pm$0.8 mg GAE/g dried extract) and it exhibited the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The cytoprotective effects of EF on oxidative damage induced by tert-butyl hydroperoxide (t-BHP) in a human hepatoma cell line, HepG2 cells, were investigated to understand the intracellular antioxidant mechanisms. Treatment of HepG2 cells with EF prior to oxidative stress was found to inhibit reactive oxygen species (ROS) generation, lipid peroxidation, and DNA damage in a dose-dependent manner. Gas chromatography-mass spectrometry (GC-MS) studies on EF resulted in tentative identification of 19 compounds representing 94.3% of the total content. Taken together, these results demonstrated that EF has excellent antioxidant activities and thus dangyuja leaves have great potential as a source for natural antioxidant which can be applied in food products.