• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.30-35
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• 2007

This study was carried out to investigate the usefulness of the aerial part of Cnidium officinale Makino as a bioactive material source. The aerial part(leaf and stem) of Cnidium officinale Makino was extracted with three kinds of solvents and determined their antimicrobial activities against several bacteria and yeast strains using the paper disc method and the microtiter dilution method. The extracts of the Cnidium offocinale aerial part exhibited the broad spectrum of antibacterial activity against Gram (+) and Gram (-) bacteria, including food-borne pathogens such as Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. The extracts of Cnidium officinale also showed antifungal activity against Saccharomyces cerevisiae. The ethyl acetate extracts completely inhibited the growth of Staphylococcus aureus and Pseudomonas aerogenes, and moderately inhibited the growth of Escherichia coli and Enterobacter cloacae at the concentration of 0.5 mg/mL. However, water extract of Cnidium officinale exhibited lower antimicrobial activity than ethyl acetate and methanol extracts. The inhibitory effect of the ethyl acetate extract of Cnidium officinale Makino was not destroyed by heating at $100^{\circ}C$ for 30 min or at $121^{\circ}C$... for 15 min. These results suggest that the aerial part of Cnidium officinale Makino could be a useful source for a natural antimicrobial material.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.340-349
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• 2009

A CJ9 bacterial strain, which showed antifungal and antibacterial activities, was isolated from meju and identified as Bacillus polyfermenticus based on Gram staining, biochemical properties, as well as its 16S rRNA sequence. B. polyfermenticus CJ9 showed the antimicrobial activity against the various pathogenic molds, yeasts, and bacteria. The antibacterial activity was stable in the pH 5.0~9.0, but the activity was lost at $37^{\circ}C$ for 24 hr. The antifungal activity was stable in the pH range of 3.0~9.0 and reduced at $121^{\circ}C$ for 15 min, but antifungal activity was not completely destroyed. The antibacterial activity was completely inactivated by proteinase K, protease, trypsin, and $\alpha$-chymotrypsin. The antifungal activity was also completely inactivated by protease and $\alpha$-chymotrypsin, and reduced its activity by proteinase which indicated that the antifungal and antibacterial compounds have proteineous nature. The apparent molecular mass of the partially purified antifungal compound, as indicated by using the direct detection method in Tricine-SDS-PAGE, was approximately 1.4 kDa. The molecular mass of the antibacterial compound could not be determined because of its heat-liable characteristic.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.403-408
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• 2012

Gelatin/Ag nanoparticle (AgNP) biocomposite was synthesized using the solution plasma process (SPP) that has been recently introduced as an effective method for synthesis of nanoparticles. In this study, gelatin/AgNP biocomposite was synthesized using various concentrations of Ag precursor ($AgNO_3$) and gelatin in the range of 1-5 mM and 1-3% (w/w), respectively, without using any chemical reducing agent. Physical properties of the gelatin/AgNP biocomposites were analyzed using EDS, FE-SEM, and TEM. The results indicated that spherical AgNPs with approximately 12~20 nm in diameter were synthesized successfully in the gelatin matrix by SPP. As the concentration of gelatin was increased (3%, w/w), disperse stability of AgNP was improved and micro-pores of gelatin became smaller and denser in the 3D scaffold. Bactericidal activity of the AgNPs was examined against Staphylococcus aureus and Escherichia coli by measuring zone of growth inhibition and decrease in colony forming unit (CFU). CFUs of S. aureus and E. coli were decreased approximately to 56% and 0%, respectively, by the gelatin/AgNP biocomposite, Ag5G3.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.168-177
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• 2017

Strain A28-5, which can degrade xylan and agar in solid medium, was isolated from a coastal seawater sample collected from Jeju Island, South Korea. This strain was found to be a gram-negative, $Na^+$-requiring bacterial strain with a polar flagellum for motility. Additionally, the strain was tolerant to antibiotics such as ampicillin and thiostrepton. The G+C content of the genome was 43.96% and menaquinone-7 was found to be the predominant quinone. Major fatty acids constituting the cell wall of the strain were $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), and $C_{18:1}$ ${\omega}7c$ (17.98%). The 16S rRNA gene sequence of the strain showed the highest similarity (98.94%) to that of Catenovulum agarivorans YM01, which was demonstrated by constructing a neighbor-joining phylogenetic tree. A28-5 was identified as a novel species of the genus Catenovulum via DNA-DNA hybridization with Catenovulum agarivorans YM01, and thus was named as Catenovulum jejuensis A28-5. The formation of tetramers and hexamers of xylooligosaccharides and (neo)agarooligosaccharides, respectively, were confirmed by thin-layer chromatography analysis using an enzyme reaction solution containing xylan or agarose with two crude enzymes prepared from the liquid culture of the strain.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.101-105
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• 2008

In order to obtain yeast cells producing a bacteriocin OR-7, the 180 bp polynucleotide corresponding to the OR-7 gene including codons for start and stop was chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Campylobacter jeuni, Escherichia coli and Pseudomonas aeruginosa. This result indicates that yeast cells producing OR-7 possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative C. jejuni, E. coli and P. aeruginosa cells. The recombinant yeast strain constructed in this study can be applied in the food preservative or animal feed.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.106-114
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• 2008

One bacterium, which showed strong antagonistic activity against H. pylori KCCM 41756, was isolated from kimchi. The strain NO1 was designated as Lactobacillus plantarum NO1 based on Gram staining, biochemical properties, and 16S rRNA gene sequencing. The culture medium $(2{\sim}4{\mu}g/ml)$ of Lb. plantarum NO1 reduced $(40{\sim}60%)$ the urease activity of H. pylori KCCM 41756. Lb. plantarum NO1 inhibited the binding of H. pylori to human gastric cancer cell line, AGS cells, by more than 33%. Lb. plantarum NO1 exhibited high viability (maintained initial viable cell count of $10^9CFU/ml$) in 0.05 M sodium phosphate buffer (pH 3.0) for 2 h, in artificial gastricjuice for 2 h and in 0.3%, 0.5% oxgall for 24 h. Hemolysis phenomena did not observed when Lb. plantarum NO1 was incubated in the blood agar media. We concluded that Lb. plantarum NO1 can be a good candidate as a probiotic, harboring anti-H. pylori activity.

• Journal of Engineering Education Research
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• v.8 no.1
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• pp.71-83
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• 2005

This paper presents an internet-based self-learning educational system which can be enhancing efficiency in the learning process of Java language. The proposed self-learning educational system is called Java Web Player(JWP), which is a Java application program and is executable through Java Web Start technologies. Also, three important sequential learning processes : concept learning process, programming practice process and assessment process are integrated in the proposed JWP using Java Web Start technologies. This JWP enables the learners to achieve efficient and interesting self-learning since the learning process is designed to enhance the multimedia capabilities on the basis of various educational technologies. Furthermore, internet-based on-line voice presentation and its related texts together with moving images are synchronized for efficient language learning process. Also, a simple and useful Java compiler is included in the JWP for providing language practice environment such as coding, editing, executing and debugging Java source files. Finally, repeated practice can make the learners to understand easily the key concepts of Java language. Simple multiple choices are given suddenly to the learners while they are studying through the JWP and the test results are displayed on the message box. This assessment process is very essential to increase the learner's academic capability.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.77-83
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• 2010

The fructus of Crataegus pinnatifida Bunge (CBF) has been used as medicinal and food source in worldwide. In this study, antimicrobial activity of the methanol extract and its sequential organic solvent fractions of CBF against different pathogenic bacteria and fungi, including multidrug resistant Pseudomonas aeruginosa and Candida sp., were investigated. The methanol extract of CBF was active against various gram-positive and gram-negative bacteria, and the ethylacetate and butanol fractions of CBF showed strong antibacterial activity against Listeria monocytogenes, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Proteus vulgaris, Escherichia coli and various multidrug resistant Pseudomonas aeruginosa with minimal inhibitory concentration of 1.0~7.5 mg/mL. Also the fractions showed anti-Candida activity against C. albicans, C. kruseis and C. geochares. The methanol extract of CBF and its solvent fractions, except n-hexane fraction, did not show any hemolytic activity against human red blood cell up to $500\;{\mu}g/mL$, respectively. The hemolysis in n-hexane fraction at $500\;{\mu}g/mL$ was less than 9.9%. Our results suggest that the CBF could be developed as a potent antibacterial agent, especially for multidrug resistant Pseudomonas aeruginosa.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.379-384
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• 2010

We isolated microorganisms presenting high enzymatic activities for amylase, cellulase, protease, lipase or fibrinolysis from Korean traditional soybean sauce and paste. Then, the physiological properties and 16S rRNA sequences of isolated microorganisms were analyzed. All of the isolated 13 strains possessing high extra cellular enzyme activities have higher amylase and cellulase activities than Bacillus subtilis KACC 10114. All the selected strains have protease activities except for D2-14. Except D8-8 and K4-1, other strains have lipase activity. D2-7, D8-8 and K4-1 strains have higher fibrinolytic activities than others, while D8-2 strain has no activity. Most of the selected strains showed antibacterial activity even in gram positive and gram negative bacteria and yeast. Gene sequence analysis of 16S rRNA from isolated strains revealed that all the selected strains were member of Bacillus species.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.255-262
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• 2010

Strain BCNU 2001 was isolated from soil samples collected from Tea-baek Mountain area. The biochemical characteristics and 16S ribosomal RNA gene sequences of the isolate revealed that the strain belonged to the Pseudomonas aeruginosa. The supernatants had an antimicrobial effect on various kind of bacteria and fungi. Especially BCNU 2001 was able to greatly inhibit the growth of Micrococcus luteus, Proteus mirabilis, Proteus vulgaris, and Aspergillus niger, and its inhibition zone was measured as 18.5 mm against Micrococcus luteus, 19.0mm against Proteus mirabilis, 17.0mm against Proteus vulgaris, and 13.5 mm against Aspergillus niger, respectively. Hexane and dichloromethane extracts of BCNU 2001 exhibited significant activity against bacteria, and dichloromethane and ethylacetate extracts showed significant activity against fungi. Pseudomonas strain BCNU 2001 was also determined to have antimicrobial peptide against various microorganisms including Gram positive bacteria, Gram negative bacteria and fungi. The obtained results may provide preliminary support for the usefulness of Pseudomonas strain BCNU 2001.