• YAKHAK HOEJI
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• v.35 no.3
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• pp.245-251
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• 1991

Selective culture of actinomycetes from soil microbes and their antibiotic producing characters by agar-disk method were examined. Some of the organisms which produced antibiotics on agar disk did not produce antibiotics in liquid culture. Further examination indicated that production of antibiotic was dependent on the composition of medium. Many streptomycestes produced antibacterial substances in tryptic soy broth but others produced antifungal antibiotics in V-8 broth. Production of antibacterial substances by Streptomyces sp. was also dependent on the medium composition.

• Korean Journal of Microbiology
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• v.54 no.2
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• pp.113-125
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• 2018

Purpose of the present study was to investigate the factors affecting the production of antibacterial substances and histamine in rennet curd prepared by inoculation of histamine-producing lactic acid bacteria (LAB) and probiotic LAB. Probiotic Lactobacillus sakei PIL52 and Lactobacillus plantarum FIL20 produced strong antimicrobial agents against histamine-producing bacteria Lactobacillus brevis LAS129, Enterococcus faecium SBP12, and Enterococcus faecalis SBP58. The lactic acid and crude bacteriocin produced from the probiotic LAB inhibited histamine-producing bacteria in a concentration-dependent manner. As the number of probiotic LAB inoculated for the production of rennet curd increased, the antibacterial activity against histamine-producing bacteria was elevated due to the increased amount of lactic acid and crude bacteriocin in the sample. The growth of probiotic LAB as well as histamine-producing bacteria was inhibited by addition of 10% NaCl, thus the antibacterial substances and histamine contents in rennet curd were significantly lower than those of the control (P < 0.05). Meanwhile, the histamine content was not significantly increased when the rennet curd prepared by mixing probiotic LAB and histamine-producing bacteria was stored at $25^{\circ}C$ for 5 days. However, the amount of histamine detected in the rennet curd was significantly (P < 0.05) increased because the antibacterial activity of the bacteriocin produced by the probiotic LAB was decreased at $20^{\circ}C$ for 20 days.

• Natural Product Sciences
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• v.20 no.2
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• pp.107-112
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• 2014

This research aimed to investigate the antibacterial activity of Lycoris radiata. The methanol extract and solvent fractions from L. radiata exhibited antibacterial activities against Escherichia coli, Staphylococcus aureus, and Helicobactor pylori. Open-column chromatography was used to isolate phytochemical constituents from L. radiata; spectroscopic analysis elucidated their structures as ${\beta}$-sitosterol (1), daucosterol (2), O-methyllycorenine (3), lycorenine (4), lycoricidinol (5), lycorine (6), and lycoricidine (7). Further testing of compounds 1 - 7 revealed antibacterial effects against E. coli, S. aureus, and H. pylori, which suggested the potential of these substances as antibacterial agents. We determined that compounds 1 and 2, isolated from the n-hexane fraction, were more effective against S. aureus and H. pylori. Compound 4, isolated from the methylene chloride fraction, exhibited noticeable antibacterial effects against E. coli. This study is the first report on the antibacterial activities of phytochemical constituents from L. radiata against E. coli, S. aureus, and H. pylori.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.231-233
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• 2003

To understand the physical method for induction of anti-bacterial substances from the silkworm larvae, Bombyx mori, three physical methods, i.e., infrared radiation, ultraviolet radiation and ultrasonic wave, have been used in this study. The results have shown that ultrasonic wave can induce anti-bacterial sub-stances effectively than radiations in the B. mori larva. The induction of anti-bacterial substances was different from silkworm race to race. Summer-autumn silkworm race (Qiufeng${\times}$Baiyu) was easy to induce antibacterial substances. It is suggested that the ultrasonic wave is a simple and easy method for induction.

• Journal of Microbiology
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• v.39 no.2
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• pp.146-148
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• 2001

Lactobacillus crispatus ATCC 33820 and L. gasseri ATCC 33323 were grown in MRS broth (pH 6.5) at 37$^{\circ}C$ for 24 h and the antibacterial activities of cell free culture supernatants were determined by the agar well diffusion method. The culture supernatants were inhibitory to Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Pediococcus acidilacticii, and Lactobacillus helveticus. The supernatants did not show any lysozyme activity. Addition of catalase did not affect the antibacterial activities of the supernatants. The antibacterial substances were heat stable (100$^{\circ}C$ for 60 min) and sensitive to proteases.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.269-272
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• 1995

Antibacterial activity test of solvent fractions, sesquiterpenoid lactones, and Compound I and II extracted from Chrysanthemum boreale M. and Chrysanthemum indium L. were performed against four microorganisms. Among the tested substances, antibacterial activities were appeared against B. subtilis and V. parahaemolyticus at the chloroform fraction, sesquiterpenoid lactones and Compound I extracted from C. boreale. But chloroform fraction and sesquiterpenoid lactones extracted from C. indicum were showed weakly than those of C. boreale. Compound II and all fractions extracted from C. indicum were not appeared against the all tested microorganisms.

• Journal of Environmental Science International
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• v.33 no.3
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• pp.205-215
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• 2024

Antibiotics are substances produced by microorganisms that kill or inhibit and are essential for infectious diseases management. This study aimed to provide basic data for overcoming antibiotic resistance in the marine bacterium LJ-18. The API 20NE and API 50CH kits were used to identify this microorganism. Morphological, physiological, and biochemical properties were investigated using MacFaddin's manuals. Subsequently, isolated LJ-18 was found to belong to a genus of Streptomyces that forms mycelia. LJ-18 also grew well at 28-32℃ on modified Bennett's agar. To isolate and purify the antibacterial compound, LJ-18 culture was divided into ethyl acetate and distilled water fractions. Considerable antimicrobial activity against various pathogenic microorganisms, including methicillin-resistant Staphylococcus aureus (MRSA), was confirmed in the C₁₈ ODS open column fractions. Peak 2 compound was obtained using reversed-phase HPLC. As a result, this compound had a significant antimicrobial activity against various pathogenic microorganisms. In particular, it showed strong activity against MRSA, Mycobacterium smegmatis, Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus.

• Korean Journal of Microbiology
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• v.15 no.2
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• pp.93-99
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• 1977

Among the Streptomyces isolated from soil, two strains which have antibacterial activity aginst various pathogenic bacteria are identified as Streptomyces globosus and Streptomyces albus subsp. according to I.S.P. methods and Bergy's Manual of Determinative Bacteriology. Morphological and physiological characteristics of them on several media were observed. Antibiotics from S. albus subsp. or S. globosus was identified asw tetracycline or streptomycin-like substances respectively by the paper chromatographic behavior in eight solvent systems of V. Betina. And it was revealed that these antibiotic substances are stable to temperature and weak acid.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.339-346
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• 2007

The MJP1 bacterial strain, which possesses antifungal activity, was isolated from meju and identified as Bacillus subtilis based on its morphological and biochemical properties, as well as its 16S rRNA sequence. Antimicrobial activity was found against various species of Gram-positive bacteria, yeasts, and molds, including food-spoilage microorganisms. The antifungal activity was found to be stable after heat and proteolytic enzyme treatment, and in the pH range of $6.0{\sim}10.0$. The antibacterial activity was stable in the pH range of $6.0{\sim}10.0$, but about 50% of the activity was lost after 24 hr at $30^{\circ}C$. The antibacterial compound was also inactivated by proteolytic enzyme treatment, indicating its proteinaceous nature. The apparent molecular masses of the partially purified antifungal and antibacterial compounds, as indicated by using the direct detection method in Tricine-SDS-PAGE, were approximately 2.4 kDa and 4.5 kDa, respectively. These studies suggest that B. subtilis MJP1 produces two bacteriocin-like substances with antifungal and antibacterial activities.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.1
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• pp.1-7
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• 2018

In this study, 1,2-hexanediol, ethylhexylglycerin, and glyceryl caprylate known as skin conditioning agents with antimicrobial activity in cosmetics were investigated for their antimicrobial activity against gram-positive and gram-negative bacteria when combining them with various ingredients in cosmetic formulations. Seven kinds of substances expected to improve the antibacterial activity in formulations were selected to blend with these three compounds.; 1,3-propanediol, 1,3-butanediol, glycerin, dipropylene glycol, niacinamide, EDTA-2Na, and ethanol. The checkerboard assay was conducted to confirm the antibacterial synergy of these seven substances and the three skin conditioning agents. Consequently, ethanol and EDTA-2Na were detected as the significant materials with synergistic effect as well as ethanol showed antibacterial synergy with all the three compounds. When seven of selected materials were mixed with glyceryl caprylate, there were synergistic or additive activity against S. aureus, gram-positive bacteria and it was suggested that the combination with 1,2-hexanediol and glyceryl caprylate was useful to control both gram-positive and gram-negative bacteria when there were four kinds of polyols. This study is meaningful in that it confirmed the antibacterial synergy of the skin conditioning agents with antimicrobial activity and the main raw materials frequently used in cosmetics, thereby contributing to prediction of the antibacterial activity of the skin conditioning agents in cosmetic formulations.