• Korean Journal of Microbiology
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• v.51 no.3
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• pp.263-270
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• 2015

A bacterial strain producing extracellular mannanases was isolated from soil of chestnut tree farm located in Gongju city of Korea by enrichment culture using Avicel as a carbon source. 16S rDNA sequence of the isolate YB-43 was highly homologous to those of genus Cellulosimicrobium strains with sequence similarities of above 99.6%. Mannanase productivity was significantly increased when the Cellulosimicrobium sp. YB-43 was grown in the presence of locust bean gum (LBG) or konjac. The mannanases were partially purified to be mannanase A (ManA) and mannanase C (ManC) by DEAE-Sepharose column and Q-Sepharose column chromatography from the culture filtrate of Cellulosimicrobium sp. YB-43 grown in LB medium supplemented with 0.7% LBG for 24 h. The partially purified ManA showed the highest activity at $55^{\circ}C$ and pH 6.5, while ManC activity was optimal at $65^{\circ}C$ and pH 7.5. ManA was stable up to $40^{\circ}C$ for 1 h, but ManC activity decreased significantly even after 1 h at $20^{\circ}C$. ManA and ManC showed difference from each other according to their substrate specificities and predominant products resulting from the mannanase hydrolysis for mannooligosaccharides. As a result, Cellulosimicrobium sp. YB-43 was found to produce two different kinds of mannanases.

• Journal of Life Science
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• v.22 no.2
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• pp.251-258
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• 2012

The purpose of this study was to investigate the probiotic properties of lactic acid bacterial strains isolated from animal feces. BCNU 9041 and BCNU 9042 isolates were assigned to Lactobacillus brevis on the basis of their physiological properties and 16S ribosomal DNA sequences analysis. They were confirmed as safe bioresources because of their non-hemolytic activities and non-production of harmful ${\beta}$-glucosidase, ${\beta}$-glucuronidase, tryptophanase, or urease. These isolates were also highly resistant to acid (at pH 2.5) and bile acids (at concentration of 0.3%, 0.6%, and 1% oxgall). In addition, they exhibited good antibacterial activity against food-borne bacteria, especially Bacillus cereus, Listeria monocytogenes, and Shigella sonnei. Furthermore, it was demonstrated that they have the highest levels of hydrophobicity and that they showed bile salt hydrolytic and cholesterol assimilation activity. These results suggest that BCNU 9041 and 9042 have good potential for application in functional foods and health-related products.

• Journal of Life Science
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• v.26 no.4
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• pp.453-459
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• 2016

Agarases are classified into α-agarase and β-agarase that produce agarooligosaccharides and neoagarooligosaccharides, respectively. Neoagarooligosaccharides have whitening effect of skin, delay of starch degradation, and inhibition of bacterial growth etc. Hence, the object of this study was to isolate a novel agarase producing marine bacterium and characterization of its β-agarase. A novel agar-degrading bacterium was isolated from seashore of Namhae at Gyeongnamprovine, Korea and purely cultured with Marine agar 2216 media. The isolated bacterium was identified as Simiduia sp. SH-4 after 16S rRNA gene sequencing. The enzymatic sample was obtained from culture media of Simiduia sp. SH-4. Enzymatic activity was highly increased from 20(30% relative activity) to 30℃ (100%) and decreased from 30 to 40℃(75%) and so more. Relative activity was 100% at pH 6 while those were about 91% and 59% at pH 5.0 and 7.0, respectively, meaning the enzyme possesses narrow optimal pH range. Hence, the enzyme exhibited the maximal activity with 120.4 units/l at pH 6.0 and 30℃ in 20 mM Tris-HCl buffer. Thin layer chromatography (TLC) analysis showed that Simiduia sp. SH-4 produces β-agarase, which hydrolyze agarose to produce biofunctional neoagarooligosaccharides such as neoagarotetraose and neoagarobiose. Hence, broad applications would be possible using Simiduia sp. SH-4 and its enzyme in the food industry, cosmetics and medical fields.

• Journal of Life Science
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• v.30 no.3
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• pp.278-284
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• 2020

Magnolia kobus is known to exert various biological effects, such as antioxidant and hypnotic activity. In this study, we investigated the antimicrobial and anti-inflammatory activity of M. kobus essential oil extracted using steam distillation. Its antimicrobial activity was tested against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa by the paper disk diffusion and minimum inhibitory concentration (MIC) methods. Its anti-inflammatory activity was evaluated by measuring its inhibition ratio on the production of nitric oxide (NO) and PGE₂ in lipopolysaccharide (LPS)-induced RAW264.7 cells. Its composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that M. kobus essential oil exhibited excellent antibacterial activity against S. aureus, with a clear zone of 18 mm and an MIC value of 0.25 mg/ml. Its clear zones against P. aeruginosa and E. coli were 14 mm and 17 mm, respectively, while its MIC values were 1 mg/ml and 0.5 mg/ml, respectively. The essential oil exhibited no cytotoxicity to the RAW264.7 cells at a concentration of 500 ㎍/ml while showing NO (37.7%) and PGE₂ inhibition (24.0%). Its three main fragrance ingredients identified were 3-carene (77.07%), β-elemene (6.92%), and caryphyllene (2.86%). The results suggest that M. kobus essential oil has potential as a cosmetic functional material with antimicrobial and anti-inflammatory effects.

• Journal of Life Science
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• v.28 no.7
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• pp.864-873
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• 2018

There has been increasing attention and research in various nanoparticle applications. Nanoparticles have been used for a variety of purposes in different departments including but not limited to cosmetics, food, machinery, and chemical. A highly sought-after field to use nanoparticles, especially natural or artificial silver nanoparticles (SNPs), is the utilization of their significant antimicrobial properties in daily items such as fabrics, indoor air filters, and, water filtration units where abundant bacterial and fungal growth are inevitable. These applications of SNPs, however, have enabled continuous human exposure and hence paved the way for potential SNP toxicity depending on exposure method and particle size. This potential toxicity has led to researches on safer antimicrobial solutions to be utilized in textile and filtration. In this context, products of natural origin have gained expanding interest due to their eco-friendly, cost-effective, and biologically safe properties along their promising antibacterial and antifungal activities. Natural product-applied fabrics and filters have been shown to be comparable to those that are SNP-treated in terms of ease production, material durability, and antimicrobial efficiency. This article summarizes and assesses the current state of in vitro and in vitro toxicity of SNPs and discusses the potential of natural products as an alternative.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.65-70
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• 2015

Antimicrobial agents or additives have commonly been used in domestic animals for the prevention and treatment of bacterial diseases. Unfortunately, this has resulted in the overgrowth of bacteria that is resistant to antimicrobial agents used by humans, and these might get disseminated to humans via the food. In this study, we investigated the prevalence of integrons, and characterized gene cassette arrays in Proteus mirabilis isolates obtained from chickens in Chungcheong province of Korea. Additionally, the correlation between gene cassette arrays and antimicrobial resistance rate was studied. A total of 26 Proteus mirabilis isolates were recovered from chickens in Chungcheong province in Korea. Antimicrobial susceptibility was determined by disk diffusion method. PCR and DNA sequencing were performed to characterize the gene cassette arrays. In addition, we employed repetitive extragenic palindromic sequence-based PCR (REP-PCR) method for clonality analysis of P. mirabilis strains. Of the 26 P. mirabilis isolates tested, 14 (53.8%) isolates carried class 1 integrons, while class 2 and class 3 integrons were not detected in our study. The class 1 integrons harbored genes encoding resistance to aminoglycosides (aacCA5, aadA2, aadA5 and aadA7), trimethoprim (dfrA17, and dfrA32), lincosamides (linF) and erythromycin (ereA). In particular, the presence of class 1 integron had a significant correlatation to a high resistance rate of aminoglycoside and trimethoprim. We confirmed that class 1 integrons are widely disseminated in P. mirabilis isolates from chickens, contributing to the resistance to diverse antimicrobial agents in Korea. To prevent further spreading of antimicrobial resistant genes among P. mirabilis isolates, constant monitoring and clinical policing will become necessary.

• KSBB Journal
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• v.21 no.5
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• pp.376-383
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• 2006

Pine needle(Pinus densiflora sieb, et zucc) extract has been used to improve cardiovascular disorders, detoxification of nicotine, the infirmities of age and curing diseases of unidentified symptoms. It has various useful components including amino acids, vitamin C, terpenoids and chlorophyll. In this study we have identified 8 different yeast strains that are developed spontaneously causing self fermentation in the extract. The self-fermented pine extract(SFPE) inhibited the growth of some bacterial strains like E. coli, Bacillus subtilis and Staphylococcus aureus. The SFPE($0.2{\mu}{\ell}/ml{\sim}0.3{\mu}{\ell}/ml$) showed 90% NBT superoxide scavenging activities which is similar for all tested samples of different ages. The 7 years old SFPE(0.15 mg/ml and 0.3 mg/ml) caused relaxation of spontaneous contraction and relaxation rhythm of thoracic arterial tissues from rat. Therefore, SFPE has useful effects such as antibacterial, antioxidant and improved blood circulation and could be a good source of functional food development.

• Research in Plant Disease
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• v.9 no.2
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• pp.94-98
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• 2003

To produce antibodies against Pseudomonas tolaasii and P. agarici, lyophilized P. tolaasii and P. agarici ($5{\times}10^7$ cfu/ml) and Freund, s adjuvant were immunized into rabbits 4 times. The specificity and sensitivity of the antibodies were evaluated by immunodiffusion test and indirect enzyme-linked immunosorbent assay (id ELISA). The ${\alpha}$-P. tolaasii antibody was very specific only against P. tolaasii, while ${\alpha}$-P. agarici antibody was not specific and showed a high cross reactivity toward P. tolaasii with detection limit concentration of $2{\times}10^3$ cfu/ml. However, the cross reactivities of ${\alpha}$-P. agarici antibody toward the related species including P. reactans were very low. Our results showed that ${\alpha}$-P. tolaasii and ${\alpha}$-P. agarici antibodies against P. tolaasii and P. agarici, respectively, might be useful for rapid and simple detection of the causal agents of bacterial brown and yellow blotches in cultivated oyster mushrooms.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.952-960
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• 2013

The objective of this study was to investigate the effect of carbohydrate source and cottonseed meal level in the concentrate on feed intake, nutrient digestibility, rumen fermentation and microbial protein synthesis in swamp buffaloes. Four, 4-yr old rumen fistulated swamp buffaloes were randomly assigned to receive four dietary treatments according to a $2{\times}2$ factorial arrangement in a $4{\times}4$ Latin square design. Factor A was carbohydrate source; cassava chip (CC) and CC+rice bran at a ratio 3:1 (CR3:1), and factor B was level of cottonseed meal (CM); 109 g CP/kg (LCM) and 328 g CP/kg (HCM) in isonitrogenous diets (490 g CP/kg). Buffaloes received urea-treated rice straw ad libitum and supplemented with 5 g concentrate/kg BW. It was found that carbohydrate source did not affect feed intake, nutrient intake, digested nutrients, nutrient digestibility, ammonia nitrogen concentration, fungi and bacterial populations, or microbial protein synthesis (p>0.05). Ruminal pH at 6 h after feeding and the population of protozoa at 4 h after feeding were higher when buffalo were fed with CC than in the CR3:1 treatment (p<0.05). Buffalo fed with HCM had a lower roughage intake, nutrient intake, population of total viable and cellulolytic bacteria and microbial nitrogen supply than the LCM fed group (p<0.05). However, nutrient digestibility, ruminal pH, ammonia concentration, population of protozoa and fungi, and efficiency of microbial protein synthesis were not affected by cottonseed meal levels (p>0.05). Based on this experiment, concentrate with a low level of cottonseed meal could be fed with cassava chips as an energy source in swamp buffalo receiving rice straw.

• Journal of Life Science
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• v.27 no.1
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• pp.44-49
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• 2017

Natural anti-oxidative compounds have important disease prevention and food preservation properties, in addition to anti-bacterial, anti-inflammation, anti-cancer, and skin whitening effects. High-performance liquid chromatography (HPLC), with an ultra vilolet (UV) detector coupled to a reverse phase C18 column and an online measurement system for 1, 1-diphenyl-2-picryl hydrazyl (DPPH) radicals, was used to search for potent antioxidative compounds in crude extracts. The online HPLC-DPPH assay was then applied to confirm antioxidative compounds in water extracts from Radix of Pueraria lobata, Rhizoma of Zingiber officinale, Fructus of Chaenomeles sinensis, Cortex of Ulmus pumila, and Radix of Astragalus membranaceus. To determine the yields of the extracts, the Brix% of each extract solution was measured using a refractometer. When the relative DPPH radical scavenging ability values of the water extracts were compared with those of a positive control (ascorbic acid), the water extracts of P. lobata, C. sinensis, and U. pumila were 7.77%, 4.71%, and 4.19%, respectively. The results suggest that this method provides a useful assay for rapid measurement of DPPH radical scavenging abilities and conformation of antioxidative compounds in natural products. Moreover, it can reduce the time spent on the separation of active compounds from natural materials, such as medicinal plants, in addition to the use of reagents for separation.