• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.410-418
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• 2019

To investigate a novel ${\beta}$-glucosidase from Bifidobacterium breve ATCC 15700 (BbBgl) to produce compound K (CK) via ginsenoside $F_2$ by highly selective and efficient hydrolysis of the C-3 glycoside from ginsenoside Rd, the BbBgl gene was cloned and expressed in E. coli BL21. The recombinant BbBgl was purified by Ni-NTA magnetic beads to obtain an enzyme with specific activity of 37 U/mg protein using pNP-Glc as substrate. The enzyme activity was optimized at pH 5.0, $35^{\circ}C$, 2 or 6 U/ml, and its activity was enhanced by $Mn^{2+}$ significantly. Under the optimal conditions, the half-life of the BbBgl is 180 h, much longer than the characterized ${\beta}$-glycosidases, and the $K_m$ and $V_{max}$ values are 2.7 mM and $39.8{\mu}mol/mg/min$ for ginsenoside Rd. Moreover, the enzyme exhibits strong tolerance against high substrate concentration (up to 40 g/l ginsenoside Rd) with a molar biotransformation rate of 96% within 12 h. The good enzymatic properties and gram-scale conversion capacity of BbBgl provide an attractive method for large-scale production of rare ginsenoside CK using a single enzyme or a combination of enzymes.

• 한국환경보건학회지
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• 제47권4호
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• pp.356-365
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• 2021

Background: Concerns have been raised regarding the criteria of groundwater, in particular in Gwangwon-do Province where many residents drink groundwater due to the poor supply of tap water and a high nonconformity rate with water quality criteria nationwide. Objectives: Water quality monitoring and risk assessment were conducted for groundwater in Hoengseong, Gangwon-do Province. Methods: A total of 46 items required for meeting drinking water criteria were analyzed from 258 samples collected from March 2017 through August 2018 (152 sites in 2017 and 106 sites in 2018). Risk assessment was conducted for two non-carcinogens (F^- and NO₃-N), and one carcinogen (i.e., arsenic) based on their high nonconformity to water quality criteria. Results: Water quality analysis revealed that the total proportion of nonconformities was determined to be 27.9%. The nonconformity rate for each content item is as follows: total colony counts (1.6%), total coliform (6.2%), Escherichia coli (1.2%), F^- (8.1%), arsenic (4.7%), NO₃-N (8.1%), pH (1.2%), manganese (0.4%), and turbidity (5.8%). Risk assessment indicated that fluoride induced a hazard quotient greater than 1 with the 95% UCL (Upper Confidence Limit) concentration of the total 258 sites and average, median, and 95% UCL concentrations of nonconformity sites. For NO₃-N, there was no human health risk. For arsenic, the excess cancer risk exceeded the acceptable cancer risk of 1×10^-6 with the average and 95% UCL concentrations of total 258 sites and average, median, and 95% UCL concentrations of nonconformity sites. Conclusions: This study suggests that it is necessary to expand water quality monitoring of groundwater and conduct a more detailed risk assessment in order to establish a health care plan for the residents of Hoengseong, Gangwon-do Province.

• 한국미생물·생명공학회지
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• 제50권2호
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• pp.255-269
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• 2022

Actinomycetes isolated from marine habitats represent a promising source of bioactive substances. Here, we report on the isolation, identification, productivity enhancement and application of the bioactive compounds of Streptomyces qinglanensis H4. Eighteen marine actinomycetes were isolated and tested for resistance to seven bacterial diseases. Using 16S rRNA sequencing analysis (GenBank accession number MW563772), the most powerful isolate was identified as S. qinglanensis. Although the strain produced active compound(s) against a number of Gram-negative and Gram-positive bacteria, it failed to inhibit pathogenic fungi. The obtained inhibition zones were 22.0 ± 1.5, 20.0 ± 1, 16.0 ± 1, 12.0 ± 1, 22.0 ± 1 and 24.0 ± 1 mm against Bacillus subtilis ATCC 6633, Escherichia coli ATCC 19404, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231 and Staphylococcus aureus ATCC6538, respectively. To maximize bioactive compound synthesis, the Plackett-Burman design was used. The productivity increased up to 0.93-fold, when S. qinglanensis was grown in optimized medium composed of: (g/l) starch 30; KNO₃ 0.5; K₂HPO₄ 0.25; MgSO₄ 0.25; FeSO₄·7H₂O, 0.01; sea water concentration (%) 100; pH 8.0, and an incubation period of 9 days. Moreover, the anticancer activity of S. qinglanensis was tested against two different cell lines: HepG2 and CACO. The inhibition activities were 42.96 and 57.14%, respectively. Our findings suggest that the marine S. qinglanensis strain, which grows well on tailored medium, might be a source of bioactive substances for healthcare companies.

• 농업과학연구
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• 제49권3호
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• pp.389-396
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• 2022

The purpose of this study was to investigate the safety of Houttuynia cordata Thunb extract (HCE) in Institute of Cancer Research (ICR) mice, to determine the effects of the extract on the growth performance and colony count, and to establish the optimal concentration of HCE. In total, 60 five-week-old male ICR mice with an average initial body weight (BW) of 27.24 ± 0.44 g were used in a four-week experiment. Mice were randomly allotted to four treatment groups (five replications per group, three mice per cage): 1) a control (CON) group fed with normal distilled water; 2) treatment group 1 (T1) fed with normal distilled water containing 0.05% HCE; 3) treatment group 3 (T3) fed with normal distilled water containing 0.1% HCE; and 4) treatment group 3 (T3) fed with normal distilled water containing 0.2% HCE. BW, feed intake (FI), and water intake were measured on the first, fourteenth, and eighteenth days. T2 showed a significant improvement (p < 0.05) in the feed conversion ratio (FCR) over the experimental period. However, water intake levels did not show significant differences among the groups. In the large intestine and feces, E. coli and Lactobacillus levels were significantly improved (p < 0.05) in the HCE treated group compared to the CON group. Supplying HCE via the drinking water improved the growth performance and colony count in ICR mice. Based on results of this study, utilizing HCE in livestock species is expected to be safe and feasible.

• 한국수산과학회지
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• 제55권6호
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• pp.875-885
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• 2022

This study was performed to confirm the optimal extraction method for antimicrobial peptides from the Hard-shelled mussel. Extractions were performed with two processes including 1% HAc/boiling and 1% HAc/non-boiling methods and used extracts for the comparison of the antimicrobial activity, protease stability, action mechanism, AU-PAGE (acid-urea PAGE), and HPLC chromatograms. 1% HAc/boiling extract showed potent antibacterial activities both against Gram-positive and negative bacterium but 1% HAc/non-boiling extract showed antibacterial activity only against Gram-positive bacteria. Treatment of 1% HAc/boiling extract with proteases retained almost antibacterial activity against B. subtilis, but abolished significant antibacterial activity against E. coli D31. Only 1% HAc/boiling extract showed two discrete clearing antibacterial zones including slow migrating and rapid migrating zones. Both extracts showed strong DNA-binding ability but did not show bacterial membrane permeabilizing ability. In comparison of the chromatogram obtained from C₁₈ or cation-exchange HPLC, the eluted peaks from 1% HAc/boiling extract showed high hydrophobic property or absorbance compared to 1% HAc/non-boiling extract, respectively. The concentration of the purified antimicrobial peptide was also higher in 1% HAc/boiling extract than in 1% HAc/non-boiling extract. Our results suggest that the effective extraction condition for antimicrobial peptides from marine invertebrate is boiling process in a weak acetic acid solution (1%).

• 생명과학회지
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• 제5권3호
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• pp.105-116
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• 1995

To investigate genomic changes in c-myc gene by a chemical carcinogen, human lymphoblast NC-37 cells were exposed to benzo(a)pyrene(BP) and dimethylbenzanthracene(DMBA), and the c-myc gene expression was evaluated by Northern and Southern blot hybridization techniques. The results are as follows: When the genomic DNA of NC-37 cells exposed to several concentrations(1.25, 2.5 and 5ug/ml) of BP concentration. However, the c-myc gene was most significantly enhanced with 2.5ug/ml of BP. The expressions of c-myc gene in NC-37 cells was stimulated by BP and DMBA. Addition of TPA reduced the gene expression BP-treated cells, whereas it enhanced the gene expression in DMBA-treated cells. The expression of c-H-ras gene was slightly increased by treatment with BP and DMBA alone and in combination with TPA, however the magnitude of increase was not significantly different between each other. The expressions of c-myc c-H-ras genes in Burkitt's lymphoma cells were greater than those in NC-37 cells. When the DNA extracted from NC-37 cells exposed to various concentrations of BP were amplified by polymerase chain reaction using a primer set containing c-myc exon I, the amplified products were of the same size in all groups. To evaluate the BP toxicity in E.coli to which human c-myc gene-cloned pBR322 vector was inserted, Southern blot hybridization was conducted on c-myc genes digested with EcoRI/HindIII and Smal/Xbal restriction enzymes, and observing that in 2 ug/ml BP-treated cells a 3.5kb fragment was generated in addition to 1.3kb fragment which can be observed in normal cells. Direct nucleotide sequence analysis of polymerase chain reaction products showed a mutation of G$\longrightarrow$A transition at the Smal recognition site.

• 한국임상수의학회지
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• 제41권1호
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• pp.8-17
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• 2024

This study was conducted to explore the efficacy of bee venom as a treatment for mastitis and to determine the optimal dosage and treatment period. When 6 mg or 12 mg of bee venom was administered to each experimental quarter of mastitis in dairy cow, the clinical symptoms in the 12 mg quarter were noticeably improved compared to those in the 6 mg quarter. There was no significant difference in the somatic cell count (SCC) in the milk between normal and mastitis quarters between the 6 and 12 mg doses, but there was a steady decrease in the 12 mg-treated quarter (p = 0.34). To determine the treatment period, bee venom was administered for 2, 4, and 7 days. After administering 12 mg of bee venom for 7 days, the SCC in the milk was compared before 6 days and after 7 days, and the SCC was significantly decreased to less than 100,000 SC/mL after 7 days (p = 0.01). In addition, to investigate the efficacy of bee venom, the minimum inhibitory concentration for S. aureus, E. coli, and coagulase negative staphylococci was measured, and the results showed that Gram-positive bacteria were more sensitive to bee venom than Gram-negative bacteria, and treatment for Gram-negative bacteria was limited. As a result of this study, it was confirmed that a dose of 12 mg of bee venom and a treatment period of more than 7 days were required to treat mastitis, and that treatment with bee venom alone against Gram-negative bacteria was negative.

• 한국축산식품학회지
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• 제44권1호
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• pp.146-164
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• 2024

Owing to the residual toxicity and adverse health effects of chemical preservatives, there is an increasing demand for using natural preservatives in food. Although many natural extracts have been evaluated, research on their antibacterial effects remains insufficient. Therefore, this study aimed to explore the possibility of developing Psidium guajava, Ecklonia cava, and Paeonia japonica (Makino) Miyabe & Takeda extracts as natural food preservatives. Further, the effect of mixing these extracts on microbial growth and quality was evaluated during the refrigeration of sausages. Optimal mixing ratios were determined based on the minimum inhibitory and bactericidal concentrations of each mixed extract against the Listeria monocytogenes, Salmonella spp. and Escherichia coli. D-optimal mixing design optimization tool was further used to obtain an optimum mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased with increasing concentration, with similar activities at 0.5% and 1%. The sausages with synthetic or natural preservatives showed significantly lower lipid oxidation than those of the control and grapefruit extract-treated sausages after 4 wk of refrigeration. Total plate counts were observed only in the control and treatment groups stored for 3 wk, and no significant effect of ascorbic acid was observed. Compared to the other samples, sausages with added natural extracts showed the highest overall acceptability scores initially and after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts had the same effect on microbiological analysis and lipid rancidity during sausage storage. Hence, this mixture can serve as a potential natural preservative in meat products.

• Journal of Microbiology and Biotechnology
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• 제34권4호
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• pp.969-977
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• 2024

Indigo is a valuable, natural blue dye that has been used for centuries in the textile industry. The large-scale commercial production of indigo relies on its extraction from plants and chemical synthesis. Studies are being conducted to develop methods for environment-friendly and sustainable production of indigo using genetically engineered microbes. Here, to enhance the yield of bioindigo from an E. coli whole-cell system containing tryptophanase (TnaA) and flavin-containing monooxygenase (FMO), we evaluated tryptophan transporters to improve the transport of aromatic compounds, such as indole and tryptophan, which are not easily soluble and passable through cell walls. Among the three transporters, Mtr, AroP, and TnaB, AroP enhanced indigo production the most. The combination of each transporter with AroP was also evaluated, and the combination of AroP and TnaB showed the best performance compared to the single transporters and two transporters. Bioindigo production was then optimized by examining the culture medium, temperature, isopropyl β-D-1-thiogalactopyranoside concentration, shaking speed (rpm), and pH. The novel strain containing aroP and tnaB plasmid with tnaA and FMO produced 8.77 mM (2.3 g/l) of bioindigo after 66 h of culture. The produced bioindigo was further recovered using a simple method and used as a watercolor dye, showing good mixing with other colors and color retention for a relatively long time. This study presents an effective strategy for enhancing indigo production using a combination of transporters.

• Tuberculosis and Respiratory Diseases
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• 제44권5호
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• pp.1072-1082
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• 1997

연구배경 : 중증 지역사회획득 폐렴은 진단방법의 향상, 항생제의 개발, 조기진단 및 치료에도 불구하고 여전히 높은 사망률을 보이는 질환으로 알려져 있다. 중증 지역사회획득 폐렴의 임상적 특정을 분석하고 예후에 영향을 미치는 인자를 규명하여 치료 및 예후 판정에 도움을 주고자 한다. 방 법 : 1989년 1월부터 1996년 7월까지 한림대학교 의료원에 내원한 40명의 중증 지역사회획득 폐렴환자를 대상으로 후향적으로 분석하였다. 원인균 동정을 위해 객담배양, 혈액배양, 기관지폐포세척액배양 및 Mycoplasma pneumoniae에 대한 항체검사를 시행하였고, 초치료로 2세대 혹은 3세대 cephalosporin, amoxicillin/clavulanic acid 등이 사용되었으며 aminoglycoside와 macrolide가 상황에 따라 병용 투여되었다. 대상군을 생존군과 사망군으로 분류하여 연령, 흡연 및 알콜중독 유무, 기저질환 유무, 저산소 혈중, 기계적 환기의 필요, 흉부 방사선상 양측성 폐 침윤 소견, 분당 호흡수, 쇼크의 유무, 혈중요소질소 및 알부민 농도 등을 비교 분석하였다. 결 과 : 남자가 2.07 : 1의 비율로 많았고 평균 연령은 $63.1{\pm}17.5$세(범위 : 25~90세)였으며 60세 이상이 65%로 다수를 차지하였다. 흡연자가 62.5%, 알콜중독자가 30%였고, 60%에서 기저질환이 발견되었으며 종류별로는 과거의 폐결핵 병변(12.5%), 만성 폐쇄성 폐질환(7.5%), 기관지 천식(5%), 기관지 확장증(2.5%), 당뇨병(22.5%) 등이었다. 가장 흔한 원인균은 S. Pneumoniae로 17.5%였으며 S. aureus 15%, K. pneumoniae 13.5%, Mycobacterium tuberculosis 7.5%였고 그 외에 coagulase negative staphylococcus, H. influenzae, P. aeruginosa, E. cloaceae, E. coli가 각각 2.5%씩 동정되어 65%의 동정율을 나타내었다. 단독 및 병용요법에서 흔히 사용된 항생제는 aminoglycoside계(75% : 30/40), 2세대 및 3세대 cephalosporin계(40% : 16/40, 27.5% : 11/40), macrolide계(27.5% : 11/4), amoxicillin/clavulanic acid(22.5% : 9/40)의 순이었다. 사망률은 37.5%였으며 사망환자의 50%가 입원후 72시간 내에 사망하였다. 예후에 영향을 미치는 인자로는 기계적 환기의 필요, 흉부 방사선 소견상 양측성 폐침윤, 혈중 알부민 농도의 저하(3.0g/dl 이하) 등이 통계적으로 유의한 차이를 보였다. 결 론 : 본 연구에서 나타난 중중 지역사회획득 폐렴의 임상적 특징과 예후인자를 바탕으로 적절한 항생제의 선택과 초기에 적극적인 진료로 치료성적을 향상시킬 것으로 기대된다.