• Journal of Life Science
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• v.19 no.6
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• pp.744-750
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• 2009

A bacterial strain producing highly viscous extracellular polysaccharide was isolated from soil. Through morphological, physiological and chemotaxonomical studies, it was identified as a Bacillus sp. and named Bacillus sp. PS-12. The extracellular polysaccharide, named PS-12 was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation and gel permeation chromatography. The purified polysaccharide was found to consist of glucose, mannose, galactose, and fucose, with a molar ratio of approximately 7:3.2:2:1, respectively. PS-12 was investigated for its immunostimulating activity on murine macrophage RAW264.7 cells using an ELISA assay. PS-12 stimulated the production of TNF-${\alpha}$ to a level 50 times greater than the control and also induced 1L-6 secretion in a dose-dependent manner. The cytotoxicity on RAW264.7 cells by PS-12 was relatively low with 10% cytotoxicity at 2 ${\mu}g$/ml. These results indicate that PS-12 is less cytotoxic to immune cells and possess immunomodulating activity in which it can produce cytokines including TNF-${\alpha}$ and 1L-6 from macrophages.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.326-331
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• 2006

In the present study, we examined biosorption characteristics of heavy metals onto the extracellular polysaccharide (EPS) produced by the purple nonsulfur photosynthetic bacteria Rhodopseudomonas sp. KH4, which was isolated from a stream in Anyang, Kyonggi-Do. When Cd (100 mg/L) and Cu (100 mg/L) were added to EPS (1.0 g/L) in the optimal condition (Cd; pH 8, Cu; pH 5, $40^{\circ}C$), 84.2 mg/L of Cd and 70.0 mg/L of Cu were adsorbed within 30 min and 10 min, respectively. When 100 mg/L of Cd and Cu were present as mixture, 16.8 mg/L of Cd and 48.7 mg/L of Cu were adsorbed at $25^{\circ}C$, pH 5. The maximum adsorption capacity determined by fitting Langmuir isotherms model was suitable for describing the biosorption of Cd (76.9 mg/g) and Cu (67.1 mg/g) by EPS. The neutral monosaccharide in the EPS determined by GC consisted of arabinose (2.4%), glucose (7.1%) and mannose (90.5%).

• The Korean Journal of Mycology
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• v.39 no.2
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• pp.99-104
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• 2011

Shiitake breeding requires the procedures of mating of two different parental strains and selection of hybrid strains that have good traits for the mushroom production. In this study, we tested the possibility of the use of chromogenic plate-based assay for extracellular enzyme production in order to assess and find good biochemical properties-possessed hybrid strains that were generated from genetic cross of the monokaryotic strains derived from two different parental strains of Lentinula edodes Sanjo-101ho and Sanjo-108ho. We observed that there was difference in the ability of producing ${\beta}$-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease among the monokaryotic strains. We could also comparatively assess that the ability of the seven extracellular enzymes production in the hybrid strains depended on the mating combination of the monokaryotic strains. Our results demonstrate that the assessment method for extracellular enzyme production using chromogenic plate assay could be usefully applied to the assessment of the hybrid strains derived from the breeding procedure of L. edodes.

• Nutritional Sciences
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• v.9 no.4
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• pp.233-239
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• 2006

Porous matrices of bioactive polymers such as polyglycolic acid (PGA) or polylactic acid (PLA) can be used as scaffolds in bone tissue growth during bone repair process. These polymers are highly porous and serve as a template for the growth and organization of new bone tissues. We evaluated the effect of PGA and PLA polymers on osteoblastic MC3T3-E1 cell extracellular mineralization. MC3T3-E1 cells were cultured in a time-dependent manner -1, 15, 25d as appropriate - for the period of bone formation stages in one of the five culture circumstances, such as normal osteogenic differentiation medium, PGA-plated, fetal bovine serum (FBS)-plated, PGA/FBS-coplated, and PLA-plated For the evaluation of bone formation, minerals (Ca, Mg, Mn) and alkaline phosphatase activity, a marker for osteoblast differentiation, were measured Alizarin Red staining was used for the measurement of extracellular matrix Ca deposit During the culture period, PGA-plated one was reabsorbed into the medium more easily and faster than the PLA-plated one. At day 15, at the middle stage of bone formation, cellular Ca and Mg levels showed higher tendency in PGA- or PLA-plated treatments compared to non-plated control and at day 25, at the early late stage of bone formation, all three cellular Ca, Mg or Mn levels showed higher tendency as in order of PGA-related treatments and PLA-plated treatments, compared to control even without significance. Medium Ca, Mg or Mn levels didn't show any consistent tendency. Cellular ALP activity was higher in the PGA- or PLA-plated treatments compare to normal osteogenic medium treatment PGA-plated and PGA/FBS-plated treatments showed better Ca deposits than other treatments by measurement of Alizarin Red staining, although PLA-plated treatment also showed reasonable Ca deposit. The results of the present study suggest that biodegradable material, PGA and also with less extent for PLA, can be used as a biomaterial for better extracellular matrix mineralization in osteoblastic MC3T3-E1 cells.

• Journal of Food Hygiene and Safety
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• v.35 no.6
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• pp.535-543
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• 2020

In addition to the ubiquitous roles of cellular RNA in genetic regulations, gene expression and phenotypic variations in response to environmental cues and chemotactic signals, the regulatory roles of a new type of RNA called extracellular RNAs (exRNAs) are an up-and-coming area of research interest. exRNA is transported outside the cell through membrane blebs known as membrane vesicles or extracellular vesicles (EVs). EV formation is predominant and conserved among all microbial forms, including prokaryotes, eukaryotes, and archaea. This review will focus on the three major topics concerning bacterially derived exRNAs, i.e., 1) the discovery of exRNA and influence of extraneous RNA over bacterial gene regulations, 2) the known secretion mechanism for the release of exRNA, and 3) the possible applications that can be devised with these exRNA secreted by different gram-negative and gram-positive bacteria. Further, this review will also provide an opinion on exRNA- and EV-derived applications such as the species-specific exRNA markers for diagnostics and the possible roles of exRNA in probiotics and the epigenetic regulations of the gut microbiome.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2001.12a
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• pp.94-94
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• 2001

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2006.04a
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• pp.9-10
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• 2006

• The Microorganisms and Industry
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• v.12 no.2
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• pp.36-39
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• 1986

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2004.12a
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• pp.105-105
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• 2004

• 한국당과학회:학술대회논문집
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• 2006.11a
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• pp.3-5
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• 2006