• 한국식품영양학회지
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• 제29권6호
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• pp.978-984
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• 2016

Osteoporosis is a disease that often occurs in postmenopausal women. The purpose of this study was to examine the positive effects of Cheongukjang powder containing menaquinone-7 (MK-7) on bone health circulation in postmenopausal women. Fifty-six postmenopausal women were recruited into a randomised double-blind placebo-controlled trial. The participants were randomly assigned into two groups. For 12 weeks, one group received $800{\mu}g$ MK-7 in the form of Cheongukjang packs (CMK-7), and the other group received the same amount of identical-looking placebo packs containing barley meal for 12 weeks. Femoral bone mineral density (BMD), bone-specific alkaline phosphatase (ALP), deoxypyridinoline (DPD), osteocalcin (OSC), serum Ca, and serum P were measured at baseline (0 weeks) and 12 weeks. After 12 weeks in the CMK-7 group, it was found that BMD, serum Ca, and serum P had increased above the baseline (p<0.0001, p=0.0028, p<0.0001), whereas bone-specific ALP, DPD, and OSC had decreased below the baseline (p=0.0003, p<0.0001, p<0.0001). Therefore, MK-7 taken as Cheongukjang is expected to prevent osteoporosis in postmenopausal women.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.762-769
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• 2020

Vitamin K2 (menaquinone) is an essential vitamin existing in the daily diet, and menaquinone-7 (MK-7) is an important form of it. In a recent work, we engineered the synthesis modules of MK-7 in Bacillus subtilis, and the strain BS20 could produce 360 mg/l MK-7 in shake flasks, while the methylerythritol phosphate (MEP) pathway, which provides the precursor isopentenyl diphosphate for MK-7 synthesis, was not engineered. In this study, we overexpressed five genes of the MEP pathway in BS20 and finally obtained a strain (BS20DFHG) with MK-7 titer of 415 mg/l in shake flasks. Next, we optimized the fermentation process parameters (initial pH, temperature and aeration) in an 8-unit parallel bioreactor system consisting of 300-ml glass vessels. Based on this, we scaled up the MK-7 production by the strain BS20DFHG in a 50-l bioreactor, and the highest MK-7 titer reached 242 mg/l. Here, we show that the engineered strain BS20DFHG may be used for the industrial production of MK-7 in the future.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.158-158
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• 1998

The non-mevalonate pathway is a newly discovered isoprenoid biosynthetic pathway in some bacteria, cyanobacteria, algae and plants. Because isoprenoid metabolites (ubiquinone, menaquinone, undecaprenol) are essential for bacterial growth, this pathway may represent a novel target for antibacterial agents. Antibiotics with a unique mechanism of action are needed to combat the risk of antibiotic resistance that is a current worldwide problem. In order to study this pathway as viable target, it was necessary to verify use of the pathway in our model system, the bacterium Bacillus subtilis. Incubation experiments with [6,6-$^2$H$_2$]-D-glucose and [l-$^2$H$_3$]-deoxy-D-xylulose were conducted to provide labeled menaquinone-7 (MK -7), the most abundant isoprenoid in B. subtilis. $^2$H-NMR analysis of the MK-7 revealed labeling patterns that strongly support utilization of the non-mevalonate pathway. Another approach to study the pathway is by structure activity relationships of proposed inhibitors of the pathway. Fosmidomycin is a phosphonic acid with antibacterial activity known to inhibit isoprenoid biosynthesis in susceptible bacteria and may act by inhibiting the non-mevalonate pathway. Fosmidomycin and an N-methyl analog were synthesized and tested for antibacterial activity. Fosmidomycin was active against Escherichia coli and B. subtilis, while N-formyl-N-methyl-3-amino-propylphosphonic acid was inactive.

• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.902-908
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• 2018

Optimization of the culture medium to maximize menaquinone-7 (MK-7) production by Bacillus subtilis strain KCTC 12392BP in static culture was carried out using statistical experimental methods, including one factor at a time, fractional factorial design, and response surface methodology (RSM). Maltose (carbon source), tryptone (nitrogen source), and glycerol (activator) were identified as the key medium components for MK-7 synthesis by the fractional factorial design, and were selected for statistical optimization by RSM. The statistical analysis indicated that, in the range that was studied, maltose, tryptone, and glycerol were all critical factors having profound effects on the production of MK-7, with their coefficients for linear and quadratic all significant at the p < 0.05 level. The established model was efficient and feasible, with a determination coefficient ($R^2$) of 0.9419. The predicted concentrations of maltose, tryptone, and glycerol in the optimal medium were determined as 36.78, 62.76, and 58.90 g/l, respectively. In this optimized medium, the maximum yield of MK-7 reached a remarkably high level of $71.95{\pm}1.00{\mu}g/ml$ after 9 days of static fermentation, which further verified the practicability of this optimized strategy.

• 한국식품저장유통학회지
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• 제30권6호
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• pp.929-943
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• 2023

This study analyzed the variation in vitamin K content in conger eel (Conger myriaster) caught off Tongyeong, Gyeongsangnam-do, Korea, focusing on the influence of size (large and small) and harvest period (monthly throughout 2021). We applied enzymatic extraction and HPLC-fluorescence methods for the analysis of vitamin K₁ (phylloquinone) and K₂ (menaquinone). The vitamin K content in conger eel varied significantly with size and harvest season (p<0.05). In large-sized samples, the phylloquinone content peaked in July (0.80±0.09 ㎍/100 g), while the highest menaquinone content was in May (0.79±0.11 ㎍/100 g). Conversely, in small-sized conger eels, the highest phylloquinone was found in December (1.94±0.15 ㎍/100 g), and the peak menaquinone level was in January (0.66±0.02 ㎍/100 g). The fat content was highest in July for large samples and in January for smaller ones. There was a positive correlation between fat and total vitamin K contents in conger eel (r=0.631, 0.667). Method validation and quality control measures ensured data reliability for vitamin K₁ and K₂ analyses. This study provides reliable information on the size and seasonal variations of vitamin K in conger eels, a staple in the Korean diet. This information is valuable for inclusion in Korea's national food nutrition database and for formulating future national health and nutrition policies.

• Applied Biological Chemistry
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• 제34권1호
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• pp.43-48
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• 1991

Menaquinone과 비슷한 구조로써 새로운 quinoline 화합물들은 design하고 합성하여 submitochondria를 이용하여 생리활성을 검정하였다. NADH-ubiquinone oxidoreductase를 저해하는 생리활성은 주로 친유성 부분인 측쇄의 길이에 의존되었다. Quinoline핵의 3위치는 methyl group일 때가 가장 높은 저해활성을 나타냈다.

• Journal of Microbiology and Biotechnology
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• 제19권6호
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• pp.588-595
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• 2009

A bacterial strain, YK-2, was isolated as a producer of trans glutaminase from a forest soil sample of Daegu, Korea. The isolate showed a G+C content of 72.7 mol%, contained meso-$A_2pm$ as the cell-wall amino acid, and possessed menaquinone MK-9 ($H_6$) and menaquinone MK-9 ($H_8$) at a ratio of 6:4. The chemotaxonomic analysis, as well as phylogenetic analysis based on the 16S rDNA sequence, identified the isolate as a member of Streptomyces platensis. For transglutaminase production, the optimum medium composition was determined to be 2% glucose, 1% polypeptone, 1% soy tone, and 0.1% $MnCl_2$. The transglutaminase was stable within the pH range of 5.0-9.0 and $30-45^{\circ}C$, and the optimum pH and temperature were pH 8.0 and $45^{\circ}C$, respectively, without any requirement for $Ca^{2+}$.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1862-1867
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• 2006

A moderately halophilic, Gram-positive, spore-forming bacterium was isolated from the roots of Blutaparon portulacoides, a plant found in sandy soil parallel to the beach line in Restinga de Jurubatiba, Rio de Janeiro, Brazil. The strain, designated $M9^T$, was motile and strictly aerobic with rod-shaped cells. It grew in the absence of NaCl and up to 20% NaCl, and was able to hydrolyze casein and starch. Strain $M9^T$ had a cell-wall peptidoglycan based on L-Orn-D-Asp, the predominant menaquinone present was menaquinone-7 (MK-7), diaminopimelic acid was not found, and anteiso-$C_{15:0}$ and iso-$C_{15:0}$ were the major fatty acids. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain $M9^T$ belonged to the genus Halobacillus and exhibited 16S rRNA gene similarity levels of 97.8-99.4% with the type strains of the other nine Halobacillus species. The DNA-DNA relatedness of strain $M9^T$ with H. trueperi, the closest relative as regards 16S rRNA gene similarity, and H. locisalis was 21% and 18%, respectively. Therefore, on the basis of phenotypic, genotypic, and phylogenetic data, strain $M9^T$ (=ATCC BAA-$1217^T$, =CIP $108771^T$, =KCTC $3980^T$) should be placed in the genus Halobacillus as a member of a novel species, for which the name Halobacillus blutaparonensis sp. nov. is proposed.

• Applied Biological Chemistry
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• 제41권3호
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• pp.208-212
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• 1998

항진균제를 개발하기 위하여 토양으로부터 700주의 세균, 방선균, 곰팡이를 분리하였으며, 이들 배양액을 조사한 결과 Candida albicans의 성장을 억제시킬 수 있는 LAM 97-44 균주를 항진균성 항생물질 생산균으로 선발하였다. 분리균주를 동정하기 위해 생산균 LAM 97-44 균주의 형태학적 특성, 배양학적 특성, 생리학적 특성, 균체성분 등을 조사하였다. LAM 97-44 균주는 $2{\sim}3{\times}1{\sim}1.5\;{\mu}m$ 크기의 포자를 형성하는 간균이며, 포자의 형태는 ellipsoid 형 이었다. LAM 97-44 균주는 arabinose, cellulose, xylose를 이용하지 못하였으나 fructose, glucose, glycerol, maltose, raffinose 등은 이용하는 것으로 나타났다. 지방산 분석결과는 iso-와 anteiso-인 성분으로 구성되어 있었으며, menaquinone은 Bacillus속 세균의 전형적인 isoprenoid 사슬이 7개인 menaquinone(MK-7)이었다. 이러한 결과를 종합하면 LAM 97-44 균주는 Bacillus subtilis와 유사한 균으로 동정되었다.

• 한국미생물·생명공학회지
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• 제25권1호
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• pp.15-22
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• 1997

A bacterial strain J-59 was isolated from a humus soil, which produced simultaneously a thermostable glucose isomerase as well as xylanase. The morphological, cultural and physiological characteristics of the isoisomerase strain J-59 were detemined by the use of the media and methods described in International Streptomyces Project. The chemotaxonomic characteristics of the isolated strain J-59 were determined by the analysis of G+C molar % of DNA, diaminipimelic acid, composition of fatty acid and menaquinone. As the results of various examinations, the strain J-59 was identified to be Streptomyces chibaensis. This strain produced glucose isomerase intracellularly and xylanase extracellularly when grown in a medium containing xylan, but it was not able to utilize the xylose or xylan as a carbon source. The glucose isomerase of S. chibaensis J59 was highly thermostable, which retained more than 75% activity in the presence of Co$^{2+}$ at 80$\circ $C for 72 h.