• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1872-1877
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• 2013

Lactic acid bacteria were selected on the basis of lactic acid producing ability from kimchi, a traditional Korean fermented food. Among the initial screening of over 150 strains selected from the sample, 27 strains were selected as lactic acid producing bacteria, and 4 strains were finally selected based on their ability to produce relatively high levels of lactic acid. The four strains were identified as Lactobacillus (L.) plantarum Gk04, Pediococcus pentosaceus Gk07, L. brevis Gk35 and L. curvatus Gk36 by the conventional morphological, cultural, physiological and biochemical characteristics, as well as by 16S rRNA sequence analysis. Among the identified lactic acid bacteria, L. curvatus Gk36 was used for soymilk fermentation. The viable cell counts and acidity values measured for the L. curvatus Gk36 were comparable to the commmercial L. acidopillus. Thus, the L. curvatus Gk36 is a potential probiotic strain to prepare fermented soy products, such as kephir, yogurt, tempeh and soy sauce.

• The Korean Journal of Mycology
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• v.45 no.3
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• pp.234-240
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• 2017

The goal of this study was to isolate wild yeasts from reed fields in the Seocheon-gun county in Chungcheongnam-do, South Korea. Molecular analysis of the D1/D2 domain of the 26S rDNA of the yeasts isolated from soil samples was performed using Basic Local Alignment Search Tool (BLAST). In total, 20 yeast strains from 11 species were isolated from 20 different soil samples. Candida species were observed to be the most common yeasts. Of these 20 strains, Candida subhashii (6 strains), Candida tropicalis (3 strains), Candida boleticola MS008, and Lachancea thermotolerans (2 strains) were identified as alcohol-fermenting yeasts. Further, Bullera japonica YJ10-1, Candida subhashii J7-1, Kluyveromyces yarrowii YJ11-1, and Ustilago shanxiensis Y10-1 were newly recorded yeast strains in Korea, and therefore, their microbiological characteristics were investigated further. All of these unrecorded yeast strains had oval cells; only Candida subhashii J7-1 formed ascospores and pseudomycelia. Kluyveromyces yarrowii YJ11-1 grew in vitamin-free medium, and all of these strains, except Candida subhashii J7-1, grew in 5% NaCl-containing YPD broth.

• The Korean Journal of Mycology
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• v.30 no.1
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• pp.44-49
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• 2002

The study was conducted to isolate and identify insecticidal bacteria for biological control of larvae of mushroom fly, Lycoriella mali, which is one of serious pests to oyster mushrooms during its cultivation period. Among eight bacteria isolated from the soil in the oyster mushroom beds and the dead body of L. mali, two bacteria, Bti-D and Bti-U showed more toxicity with mortality rate than other six-bacteria isolates. The two bacteria showed more toxicity in three instar of the period of development of the mushroom fly than in other instar. Symptoms of the larvae of L. mali infected by the two bacteria developed as follows: at the early infection, the front middle gut changed color to light brown, the middle gut to brown, whole body to black brown, and eventually, the fly died. For the identification of these isolates, cultural and biochemical characteristics by Bergey's manual and Biolog system, cell morphology by TEM, endospore and endotoxin by phase-contrast microscope, and test using 33H antisera were examined. According to the results, these two isolates, Bti-D and Bti-U were identified as Bacillus thuringiensis subsp. israelensis respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.19-24
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• 1978

The differences in Vibrio parahaemolyticus detection ratio were compared between the isolation methods, the Most Probable Number technique and single dilution tube method. During the period from February to October in 1976, 298 samples of sea water, 112 of bottom deposit, 169 of shellfish, and 80 of fish samples collected along the south coastal area of Korea were examined to determine the detection ratio of Vibrio parahaemolyticus. It was often observed that Vibrio parahaemolyticus was detected in higher diluted samples even through negative in lower dilution. Three hundred and forty three samples out of 659 samples submitted to the test by MPN procedure appeared positive for Vibrio parahaemolyticus showing $52\%$ detection ratio. Whereas only 149 samples, corresponding $22.5\%$, were positive for Vibrio parahaemolyticus in the lowest dilution grade. The positive result was $24.5\%$ in the lowest dilution grade and $50\%$ by MPN Procedure in sea water samples, $28.6\%$ and $65.2\%$ in bottom deposit, $22.5\%$ and $56.2\%$ in shellfish and $7.5\%$ and $32.5\%$ fish samples. When tested by triplicate tubes, $61.7\%$ of 149 Vibrio parahaemolyticus positive samples appeared positive in one tube, $28.9\%$ of them were positive in two tubes and $9.4\%$ of them were positive in all three tubes. The detection ratio determined by MPN procedure was more than two times higher than that of single dilution in triplicate tubes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.227-236
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• 1995

The objective of this research was to characterize fucoidans isolated from Laminaria religiosa and Undaria pinnatifida in Korea to obtain basic data for Production of soluble dietary fiber materials with biological functionality. Fucoidans were successively extracted 3 times at $65\%$ for 1hr with arid solution of pH 2.0, and cetylpyridinium chloride was used for partial purification. The yields of partially purified fucoidans were $2.71\%$ for L. religiosa, $6.65\%$ for sporophylls of U. pinnatifida and $0.40\%$ for blade of U. pinnatifida. The yield from sporophylls of U. pinnatifida was highest among the sample tested, whereas the yield from blade of U. pinnatifida was lowest. It appeared that the fuconidans content in different parts of U. pinnatifida varied. Partially purified fucoidans were separated into 3 fractions by DEAE-Sephadex A-25 ion exchange column and the maior fractions were refractionated with tractional precipitation with ethanol. $60-70\%$ ethanol precipitated fractions of 1. religiosa and sporophylls of U. pinnatifida turned out to be homogeneous by cellulose acetate electrophoresis and gel filteration chromatography. The molar ratios of fucose, galactose, and sulfate in the purified fucoidans(ethanol precipitated fractions) were 1 : 0.31 : 2.43 for L. religiosa and 1 : 0.97 : 1.99 for sporophylls of U. pinnatifida. The averaged molecular weights of the purified fucoidans from L. religiosa and sporophylls of U. pinnatifida were 31,000 and 38,000, respectively.

• Current Research on Agriculture and Life Sciences
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• v.10
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• pp.125-135
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• 1992

Nine strains of xyl mutants that could not utilize xylose as a carbon source were isolated from E. coli JM109 by the treatment of NTG in order to investigate the regulation of xylose operon and to use recipient cells for the cloning of xylR gene. For the characterization of all isolated mutants, colony colors of all mutants on MacConkey-xylose and MacConkey-xylulose agar plate were observed for the utilization of xylose and xylulose, and the growth level and the activity of xylose isomerase and xylulokinase were determined in need. The isolated xylR/T mutants formed the white colony on MacConkey-xy-lose and MacConkey-xylulose agar plate. They did not detect the activity of xylose isomerase, and the activity of xylose isomerase was not restored in transformants of xylR/T mutant with pEX13 which contained xylA gene. xylR and xylT mutants were classified from xylR/T mutants depending upon the growth level in minimal medium. xylT mutants; DH13, DH121 and DH125 could grow a little in that medium, but xylR mutants; DH10, DH53, and DH60 could not grow that medium.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.863-872
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• 2015

Kernel rootkit is recognized as one of the most severe and widespread threats to corrupt the integrity of an operating system. Without an external monitor as a root of trust, it is not easy to detect kernel rootkits which can intercept and modify communications at the interfaces between operating system components. To provide such a monitor isolated from an operating system that can be compromised, most existing solutions are based on external hardware. Unlike those solutions, we develop a kernel introspection system based on the ARM TrustZone technology without incurring extra hardware cost, which can provide a secure memory space in isolation from the rest of the system. We particularly use a secure timer to implement an autonomous switch between secure and non-secure modes. To ensure integrity of reference, this system measured reference from vmlinux which is a kernel original image. In addition, the flexibility of monitoring block size can be configured for efficient kernel introspection system. The experimental results show that a secure kernel introspection system is provided without incurring any significant performance penalty (maximum 6% decrease in execution time compared with the normal operating system).

• Strategy21
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• s.39
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• pp.82-113
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• 2016

This paper analyzes the contents and the effects of the UNSC 2270, and its implications to South Korea's defense strategy and navy. The UN Security Council passed strong sanctions against North Korea which punish North Korea's 4^th nuclear test. The sanctions compared to the previous ones require international society to take practical actions such as comprehensive trade bans as well as diplomatic isolation which will put significant pains on North Korea. Especially, these measures would greatly hamper economic development policy of Kim Joung-un regime. Because Kim Jung-un regime has inherent legitimacy problems which stems from the third family succession of the power, economic difficulties may play an important cause on the regime instability in the long term. In fact, the United States sees this possibility as an option to coerce North Korea in which North Korea choose denuclearization for its regime survival. Nevertheless, the prospects of the UN sanctions are not so optimistic. Considering North Korea's willingness for nuclear development and its level of nuclear technology, North Korea will try to play a gambit with the US and South Korea by exploiting its strategic advantages. North Korea's response will have three following strategies. First, it would actively pursue political and economic survival strategy by using China's support for the regime, strengthening its power grip in the name of countering US hostile policy, and enhancing peace propaganda. Second, North Korea will accelerate efforts to position its status as a nuclear de facto state. For this purpose, it could create nuclear crisis on the peninsula. Third, it would exploit local provocations as an exit strategy to get over the current situation. In order to counter North Korea's actions and punish North Korea's behavior strongly, South Korea needs following strategies and efforts. It should first make all the efforts to implement the UN sanctions. Strong and practical nuclear deterrence strategy and capability with the U.S. should be developed. Effective strategy and capabilities for the prevention and deterrence of North Korea's provocation should be prepared. For this purpose, North Korea's provocation strategy should be thoroughly reviewed. Active international cooperation is needed to punish and coerce North Korea's behavior. Finally, South Korea should prepare for the possible occurrence of North Korea's contingency and make use of the situation as an opportunity to achieve unification. All these strategies and efforts demand the more active roles and missions of South Korea's navy and thus, nullify North Korea's intention militarily.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.1
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• pp.25-31
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• 2005

A soil bacterium, Bacillus subtilis HJ927, exhibiting strong antagonistic property against pathogenic fungi was isolated from pepper fields infested with Phytophthora capsici. Pepper plants inoculated with P. capsici revealed severe root mortality while plants co-inoculated with B. subtilis HJ927 and P. capsici showed drastically reduced root mortality. Low molecular weight substances released by B. subtilis HJ927 mediated the plant protective effect. The anti-fungal compounds released by B. subtilis HJ927 were identified as 3-methylbutyric acid, 2-methylbutyric acid, and methyl 2-hydroxy, 3-phenylpropanoate by high-performance liquid chromatography and gas chromatography-mass spectrometry. In addition to these compounds, B. subtilis HJ927 also produced ${\beta}$-1,3-glucanase, a hydrolytic enzyme implicated in antifungal activity.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.330-336
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• 2011

Bacterial strains exhibiting fibrinolytic activity were screened from traditional Korean soybean sauce. The Fibrinolytic activities of the various isolated microorganism were further examined and the superior strain YJ11-21 was selected for further analyses. Gene sequence analysis of 16S rDNA of the YJ11-21 strain revealed Bacillus licheniformis. Optimal culture conditions were investigated in order to maximize the production of the fibrinolytic enzyme by YJ11-21. Amongst the carbon sources tested, glucose was the most effective for enzyme production and amongst the nitrogen sources tested, yeast extract was seen to be the most effective. A one percent addition of NaCl to the medium resulted in the highest fibrinolytic activity. Interestingly, a 10% addition of NaCl resulted in a high activity together with a high cell growth rate. Therefore, YJ11-21 is speculated of being a halotolerant. The optimum pH and temperature for enzyme production were a pH of 9.0 and $30^{\circ}C$, respectively.