• Korean Journal of Microbiology
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• 제46권2호
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• pp.127-133
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• 2010

The purpose of this work was to investigate the antibacterial activity derived from a lactic acid bacterium, Lactococcus lactis HK-9, isolated from the feces of a 2-day newborn infant. We characterized the physiological and biochemical properties of this strain. Both the BIOLOG system and phylogenetic analysis using 16S rRNA sequencing were utilized for identification, and the strain was assigned to the Lactococcus lactis species, designated as L. lactis HK-9, and registered in GenBank as [GU936712]. We monitored growth rate, production of lactic acid and acetic acid as metabolites, and pH during growth. The maximum concentrations of lactic acid and acetic acid reached 495.6 mM and 104.3 mM, respectively, and the initial pH of the cultures decreased from 7.0 to 4.1 after incubating for 60 h. HPLC was used to confirm the production of lactic acid and acetic acid. Significant antibacterial activity of the concentrated supernatant was demonstrated against Gram-positive (e.g., Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, MRSA) and Gram-negative (e.g., Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella sonnei) bacteria by the plate diffusion method. The antibacterial activity was sensitive to protease, and the molecular weight of the presumed bacteriocin molecule was estimated to be about 4 kDa by tricine-SDS-PAGE.

• Korean Journal of Food Science and Technology
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• 제44권1호
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• pp.69-75
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• 2012

To investigate the effects of soybean germination time on the quality of cheonggukjang, the physicochemical characteristics and enzyme activities of cheonggukjang during fermentation were compared. B. subtilis SCD 115035 strain isolated from traditional cheonggukjang was selected for making cheonggukjang. Germinated (12-h) soybeancheonggukjang produced the highest amount of viscous substance (13.22%) after 48 h of fermentation, and the contents were inversely proportional to the germination time of the soybeans. The acidic- and neutral-protease activities of ungerminated soybean-cheonggukjang were higher than those of germinated soybean-cheonggukjang. The amino nitrogen content of ungerminated soybean-cheonggukjang was the highest (436.93 mg%) at 48 h of fermentation, and its content was similar to that of 12-h germinated soybean-cheonggukjang. However, the total isoflavone content of 36-h germinated soybean-cheonggukjang was the highest after 72 h of fermentation, and its content was higher than those of cheonggukjang made from soybeans germinated for 0, 12, and 24 h.

• Applied Biological Chemistry
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• 제41권7호
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• pp.489-495
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• 1998

The optimum culture condition of Scopulariopsis brevicaulis for the production of ${\alpha}$-galactosidase was as follows: Tryptone 1.5%, $NH_4NO_3$ 0.2%, Raffinose 2.5%, $KH_2PO_4$ 0.5%, yeast extract 0.5%, pH 7.0, $27^{\circ}C$. The optimum pH and temperature for the enzyme activity of ${\alpha}$-galactosidase producing Scopulariopsis brevicaulis were pH 7.0 and $27^{\circ}C$, respectively. The enzyme was relatively stable at $pH\;6.0{\sim}8.0$ and at temperature below $40^{\circ}C$. The activity of the enzyme was inhibited by $Ag^{2+},\;Hg^{2+},\;Cu^{2+}$, p-chloromercuribenzoic acid and Iodine. These results would indicate the presence of -SH groups in the catalytic site of the enzyme. Km value was 1.9 mM for $p-nitrophenyl-{\alpha}-D-galactopyranoside$ and Vmax value was $9.66{\times}10^2\;{\mu}M/min$. Sugar constituents of culture broth were identified by HPLC that the enzyme liberated sucrose, glucose and fructose from raffinose and raffinose was significantly decreased.

• The Korean Journal of Applied Statistics
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• 제5권2호
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• pp.123-137
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• 1992

We analyzed a time series composed of the annual precipitations of Seoul based on the measurements of a Korean raingage and a modern raingage. The precipitations measured with a Korean raingage for the period of 1771 to 1907 are followed by the precipitations with a modern raingage for the period of 1908 to 1990. The latter part of the time series of annual precipitations were obtained from a book for annual precipitations of Korea by Korea Meteorological Administration and the former from Wada's table 1 for monthly precipitations reproduced from the daily rainfall measurements by a Korean raingage for the period of the Yi Dynasty. In our analysis three different precipitation regimes clearly stand out of the entire period. In order to define objectively the period of each precipitation regime we made a time series of 9 year moving averages from the above time series. By taking into account the shapes of the moving average time series and by using a threshold value of annual precipitation 1050 mm, we defined three precipitation regimes of wet period 1(WP1), dry period (DP), and wet period 2 (WP2). The WP1 and WP2 show very similar characteristics in out statistical analyses. On the other hand, DP is very different from the two periods in many statistical aspects. The strong similarities of the WP1 and WP2 regimes in the magnitudes of statistical parameters and in the shapes of their power spectrum distribution are supporting very positively the soundness of precipitation amounts measured with a Korean raingage in spite of numerous conceivable errors which might have been introduced into measurements of precipitation due to changes of observation site and environment, the scale of units employed, and urbanization of Seoul, etc. However, the annual precipitation amounts are not enough to examine throughly the characteristic of precipitation variations during the two regimes. It is definitely necessarly to recover the daily amounts of precipitation, based on two or three times measurements of rainfall with a Korean raingage, scattered in various ancient documents such as the official diary of 'Seungjeong-weon'

• Korean Journal of Microbiology
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• 제47권4호
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• pp.308-315
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• 2011

The purpose of this work was to examine the antimicrobial activity derived from the lactic acid bacterium, UK-3 isolated from the vaginas of women of childbearing age. Various physiological and biochemical properties of this strain were characterized. Both the BIOLOG system and phylogenetic analysis using 16S rRNA sequencing were utilized for identification, and the strain was designated as Lactobacillus plantarum UK-3, and registered in GenBank as [JK266589]. Growth rate, production of organic acids (e.g., lactic acid and acetic acid), and pH during growth were monitored. The maximum concentrations of lactic acid and acetic acid were approximately 684.11 mM and 174.26 mM, respectively, and pH changed from 7.0 to 3.7 after 72 h of incubation. High performance liquid chromatography was used to confirm lactic acid and acetic acid production. Significant antimicrobial activity of the concentrated supernatant was demonstrated against various Gram-positive (e.g., Staphylococcus aureus, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Neisseria species., Listeria monocytogenes), Gram-negative bacteria (e.g., Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis), and yeast (e.g., Candida albicans) by the plate diffusion method. As a result, the concentrated L. plantarum UK-3 cultures had lower acidity and inhibited the growth of all microorganisms tested, whereas the growth of L. acidophilus was not affected.

• Clinical and Experimental Reproductive Medicine
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• 제33권3호
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• pp.171-178
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• 2006

Objective: Human embryonic stem (ES) cells have a great potential in regenerative medicine and tissue engineering. The human ES cells could be differentiated into specific cell types by treatments of growth factors and alterations of gene expressions. However, the efficacy of guided differentiation and isolation of specific cells are still low. In this study, we characterized isolated cells from differentiated human ES cells by magnetic activated cell sorting (MACS) system using specific antibodies to cell surface markers. Methods: The undifferentiated hES cells (Miz-hESC4) were sub-cultured by mechanical isolation of colonies and embryoid bodies were spontaneously differentiated with DMEM containing 10% FBS for 2 weeks. The differentiated cells were isolated to positive and negative cells with MACS system using CD34, human epithelial antigen (HEA) and human fibroblast (HFB) antibodies, respectively. Observation of morphological changes and analysis of marker genes expression were performed during further culture of MACS isolated cells for 4 weeks. Results: Morphology of the CD34 positive cells was firstly round, and then it was changed to small polygonal shape after further culture. The HEA positive cells showed large polygonal, and the HFB positive spindle shape. In RT-PCR analysis of marker genes, the CD34 and HFB positive cells expressed endodermal and mesodermal genes, and HEA positive cells expressed ectodermal genes such as NESTIN and NF68KD. The marker genes expression pattern of CD34 positive cells changed during the extension of culture time. Conclusion: Our results showed the possibility of successful isolation of specific cells by MACS system from undirected differentiated human ES cells. Thus, MACS system and marker antibodies for specific cell types might be useful for guided differentiation and isolation of specific cells from human ES cells.

• Korean Journal of Clinical Laboratory Science
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• 제54권2호
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• pp.110-118
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• 2022

Candidemia is a major cause of nosocomial infections resulting in increased morbidity and mortality. It remains a serious risk in inpatients and increases medical treatment costs. From 2009 to 2018, Candida strains (3,533) isolated from blood culture tests at the S Hospital were analyzed according to the period, year, sex, age, ward, etc. During the entire period, 54,739 of 717,996 blood culture tests showed a positive rate (7.6%) and the Candida isolation rate was 3,533 (6.4%) out of 1,036 patients. Among the Candida isolates, C. albicans was most common (33.8%), followed by C. tropicalis (28.6%), C. glabrata (19.8%), C. parapsilosis (7.8%), and C. krusei (4.0%). In early (2009~2013)/late (2014~2018) isolation, C. tropicalis decreased by 3.8% and C. glabrata increased by 3.4%. After 50 years of age, the higher the separation frequency. C. parapsilosis (31.3%) in 1~10s, C. tropicalis (30.3%) and C. glabrata (27.6%) in 41~50s, and C. tropicalis (28.6%) in 80s are relatively frequent. has been separated C. krusei was isolated in a relatively high proportion from females (60.9%). Therefore, a systematic and continuous nosocomial infection control system should be established for appropriate treatment as per antifungal treatment guidelines. The system should continuously monitor the distribution of Candida species and provide rapid identification results.

• Journal of Mushroom
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• 제10권2호
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• pp.83-92
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• 2012

To provide a basis for the variation of fruit bodies of winter mushroom (Flammulina velutipes), the organic acid composition of its fruit bodies was investigated with several varieties of winter mushroom indifferent temperature and storage period. In the fruit bodies of winter mushroom, a total of 10 organic acids including acetic acid, butyric acid, citric acid, fumaric acid, DL-isocitric acid, L(+)lactic acid, D-malic acid, propionic acid, succinic acid, and D-tartaric acid were detected. In the most of the winter mushroom, acetic acid was the main organic acid component and fumaric acid was the least included component. Acetic acid, which is a mono-carboxyl group of organic acid, is contained in different levels according to different varieties and different storage temperature. Butyric acid is extremely variable in its quantity, depending on variety and different storage temperature. In contrast, fumaric acid, which is a dicarboxyl group of organic acid, decreased in its quantity during storage with 1.5 mg/g. Especially, ASI 4149, 4166 varieties tend to differ in their quantity. Besides, malic acid is extremely variable in its quantity according to variety and storage temperature. Citric acid, a tri-carboxyl group of organic acid, increased in its quantity according to storage period, which enables us to efficiently manage storage period. Isocitric acid is also extremely variable in its quantity according to variety, storage temperature and storage period.

• Journal of Applied Biological Chemistry
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• 제60권4호
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• pp.383-390
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• 2017

Regarding the facts that fat, which is easily oxidized, is one of the major responsible factors affecting the quality of aroma, and polyphenol compounds including chlorogenic acid (CGA) contribute the anti-oxidative activities to coffee, we investigated fat oxidation, conversion of CGA, and changes of anti-oxidative activities according to the degree of roasting and storage of 60 days. We found that the amount of extractable fat by diethyl ether is increased as the coffee beans are roasted longer. Furthermore, the acidity values of the fat are increased from $8.91{\pm}0.16$ to $17.81{\pm}0.11$, and $10.37{\pm}0.27$ to $17.93{\pm}0.09$ in the medium and dark roasted coffee beans, respectively, while it is increased from $4.47{\pm}0.11$ to $11.89{\pm}0.18$ in the green coffee bean after 60 days. The CGA contents in the coffee beans were decreased from $310{\pm}8.2$ to $282{\pm}11.2$, then to $58{\pm}0.0mg$ in 10 gr of the green, medium and dark beans, respectively, and were not changed significantly during the storage period. However, the anti-oxidative activities measured by 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical scavenging assays were not significantly different among the green, medium, and dark coffee beans during the storage period. Furthermore, antioxidant reactive element-luciferase assay showed that biological anti-oxidative activities were increased as coffee beans were more roasted and stored longer. As the total polyphenolic contents in the beans were significantly decreased by roasting, the results suggests that other molecules, such as, Maillard reaction products might play substantial role in anti-oxidative activity and influence cup quality of coffee.

• Korean Journal of Ichthyology
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• 제27권2호
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• pp.104-115
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• 2015

The species composition of larval fish assemblages in the Nakdong River estuary, Korea, was determined using monthly samples collected between September 2010 and August 2011 at two stations. A total of forty three larval species were collected during the study. Among forty three taxa of fish larvae, summer gobies, Clupea pallasii, Engraulis japonicus, spring gobies, Konosirus punctatus, winter gobies, Sardinops melanostictus, Coilia nasus were dominant taxa, and these eight taxa accounted for 95.0% in the total number of individuals. Species composition and abundance varied greatly spatio-temprally showing the peak abundances of fish larvae in August 2011, and a few fish larvae were occurred in November 2010. Cluster analysis based on the number of individuals of fish larvae showed that 21 month-station sampling units were classified into five groups at the similarity level of 50%, and the results of ANOSIM and SIMPER analysis revealed significant differences in community structure among five groups.