• Korean Journal of Microbiology
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• v.41 no.1
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• pp.67-73
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• 2005

Photoautotrophic bacteria are promising candidates for the production of poly(3-hydroxybutyrate) (PHB) since they can address the critical problem of substrate costs. In this study, we isolated 25 Tn5-inserted mutants of the Synechocystis sp. PCC 6803 which showed enhanced PHB accumulation compared to the wild-type strain. After 5-days cultivation under nitrogen-limited mixotrophic conditions, the intracellular levels of PHB content in these mutants reached up to $10-30\%$ of dry cell weight (DCW) comparable to $4\%$ of DCW in the wild-type strain. Using the method of inverse PCR, the affected genes of the mutants were mapped on the completely known genome sequence of Synechocystis sp. PCC 6803. As a result, the increased PHB accumulation in 5 mutants were found to be resulted from defects of genes coding for NADH-ubiquinone oxidoreductase, O-succinylbenzoic-CoA ligase, photosystem II PsbT protein or histidine kinase, which are involved in photosystem in thylakoid inner membrane of the cell. The values of $NAD(P)H/NAD(P)^+$ ratio in the cells of these mutants were much higher than that of the wild-type strain as measured by using pulse-amplitude modulated fluorometer, suggesting that PHB synthesis could be enhanced by increasing the level of cellular NAD(P)H which is a limiting substrate for NADPH-dependent acetoacetyl-CoA reductase. From these results, it is likely that NAD(P)H would be a limiting factor for PHB synthesis in Synechocystis sp. PCC 6803.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.317-323
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• 2014

Violacein has received much attention due to its various important biological activities, including broad-spectrum antibacterial and antifungal activity, anti-malarial, anti-tumoral, anti-oxidant, and anti-diarrheal activities. EP15224 strain isolated from forest soils in Korea was found to be a new species belonged to the genus Massilia based on its 16S ribosomal DNA sequences. The 16S ribosomal DNA of strain EP15224 displayed 97% homology with Massilia sp. BS-1, the nearest violacein-producing bacterium. Strain EP15224 produced bluish-purple pigment well in a synthetic MM2 medium containing glucose, $(NH_4)_2SO_4$, $Na_2HPO_4{\cdot}7H_2O$, $KH_2PO_4$, $MgSO_4{\cdot}7H_2O$, and 1 mM $\small{L}$-tryptophan. The chemical analysis of the pigment by LC/MS/MS showed that it is violacein with molecular weight of 343.34. This is the second report on the production of violacein by a Massilia species. In this study, the optimal culture conditions for violacein production were established under which 280 mg/l crude violacein was produced : glucose 2 g/l, $(NH_4)_2SO_4$ 1 g/l, $Na_2HPO_4{\cdot}7H_2O$ 2 g/l, $KH_2PO_4$ 1 g/l, $MgSO_4{\cdot}7H_2O$ 0.1 g/l, L-tryptophan 0.24 g/l, 25 ml medium in a 250 ml flask, with an inoculumn size of 10% (v/v), 72 h of cultivation with 250 rpm at $25^{\circ}C$.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.79-90
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• 2013

The altitude range of habitats in which Fairy Pitta inhabited in 1960s is different from the present in Jeju Island. We studied on the habitat environment to understand the causes of difference through the comparison of satellite image data(Landsat) between 1975 and 2002, the literature review in relation to habitats, vegetations, and forest landscapes. The area of below 600m asl.(above sea level) where is mainly Fairy Pitta inhabited at the present with a lot of forests, was massive pasture with small isolated forests nearby valley. The forests were broad-leaved evergreen forests, and second forests with poor condition in the size and forest structure. The forests around 700m asl. were also second forests with approximately 3m height trees. The forests from 800m to 1300m asl. were also disturbed by mushroom cultivation by local people. The authors believe that Fairy Pitta could not inhabited in the area above 1300m because of the poor forest conditions in the size and structure in which consist of Ilex crenata, Rhododendron mucronulatum var. ciliatum and coppice forests. Therefore it might be possible that the best forests for the Fairy Pitta habitat were located in the area of 1,000m to 1,300m above sea level in 1960s. Compared to present habitats, forests at 100m up to 800m above sea level, the authors believe that the size of habitats were smaller with less population of Fairy Pitta. Since 1960s the forest landscape of Jeju Island has been improved successfully, and because of that the population of Fairy Pitta also has been increased. To protect the Fairy Pitta and habitats in Jeju Island, it is suggested that sustainable forest management focusing on the species composition and stand structure maintain or enhance the biodiversity.

• Journal of Mushroom
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• v.3 no.4
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• pp.133-139
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• 2005

Fruiting bodies of Cordyceps have been regarded as popular folk and effective medicines to treat human diseases such as asthma, bronchial and lung inflammation, and kidney disease. Cordyceps pruinosa (Clavicipitaceae; Hypocreales; Ascomycotina) has received special attention for medicinal purpose due to its various physiological activites. The nucleoside derivative N6-(2-hydroxyethyl) adenosine (HEA) isolated from it showed a $Ca^{2+}$ antagonistic effect and negative inotropic response. The artificial production of fruiting body of C. pruinosa has not been tried successfully yet by using living silkworm substrate. To develop techniques for the production of C. pruinosa stromata on a large scale, the infection of Bombyx mori with C. pruinosa and the growth characteristics of stroma of C. pruinosa were investigated. Also, studied about biological activities of fruiting body formed on silkworm. Infection rate of the silkworm pupae with C. pruinosa was the highest in injection inoculation. The formation of the fruiting body of C. pruinosa was quite good in the room controlled at $21{\sim}25^{\circ}C$, over 91% of relative humidity and over 1500 lx. Glucose concentration was high in the fruiting bodies of the silkworm pupae infected with C. pruinosa on a dry weight basis. The most abundant amino acid in the fruiting bodies was arginine and phenylalanine. The fruiting bodies of silkworm pupae infected with C. pruinosa was rich in oleic acid. The high amount of citric acid was found in the fruiting bodies of silkworm pupae infected with C. pruinosa.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.449-455
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• 2010

'Moulinrouge' was selected as the best regenerating cultivar among 18 different spray-type chrysanthemum cultivars bred in the Gyeongnam Flowers Breeding Research Institute. When the leaf explants from standard- and spray-type chrysanthemum 'Jinba' and 'Moulinrouge' were incubated on MS basal medium supplemented with $0.5mg{\cdot}L^{-1}$ BA and $1.0mg{\cdot}L^{-1}$ NAA, both 'Jinba' and 'Moulinrouge' induced adventitious shoots that can be regenerated into plantlets. Based on these regeneration conditions, we developed an efficient $Agrobacterium$-mediated chrysanthemum 'Moulinrouge' transformation method by using sequential selection of shoots from low ($10mg{\cdot}L^{-1}$) to high ($30mg{\cdot}L^{-1}$) concentrations of kanamycin after co-cultivation of leaf explants with $Agrobacterium$ for 10 days and induction of shoots. All kanamycin resistant plants investigated with genomic PCR analysis carried the report gene, $AtSICKLE$, in their genome. Although expression levels of the report gene in the transgenic plants investigated with RT-PCR were relatively low because of inefficiency of CaMV 35S promoter in chrysanthemum, transgenic lines expressing $AtSICKLE$ efficiently showed leaf epinasty phenotype. We expect that our results will provide a useful method that can perform a high-throughput investigation of genes isolated and studied well in model plants for molecular breeding of chrysanthemum.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.509-518
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• 2019

This study was conducted to investigate single crossing condition of M. sacchariflrous and M. sinensis for breeding of M. ${\times}$ giganteus cultivar. Compared with natural day length condition, cultivation in short day length condition shorten days to heading to 18~27 days in both species. Pollen germination ratio of were 75.8% at 6 o'clock in M. sacchariflorus and 51.9% at 7 o'clock in M. sinensis but decreased to below 10% at 8 o'clock in both species. When cut ears immerged in 150 mL of cut-flowers conservation solution and isolated with covering of white non-woven fabric, flowering and pollen dispersal were persisted for 7 days, and the ratio of pollen germination were above 40% for 4 days. The ratio of self-fertilization of both species were below 2.5%, but open pollenation ratio were above 50%. We obtained 437 seeds with experimental single cross of 14 combinations between tetraploid M. sacchariflorus and diploid M. siensis by application of developed single crossing methods. In the single cross, numbers of seed set were different by mother plants. Thus, the newly investigated single crossing condition will be used to breed M. ${\times}$ giganteous cultivar which is sterile and has superior characteristics of biomass yield.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.384-397
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• 2018

The aim of this study is to screen the strains of Bacillus spp. possessing safety, probiotic activity, and so on, which can be utilized as probiotic resource for using the feed and supplement food of companion animal. About 300 isolates were isolated from traditional Korean sauces, four isolates that did not have or produce the six kinds of B. cereus type vomiting and diarrhea toxin genes, ${\beta}$-hemolytic, and three kinds of carcinogenic enzymes were selected. Antibiotic gene retention, cell surface hydrophobicity, antibiotic sensitivity, and glucose utilization were analyzed for four isolates, and finally SRCM 100731 was selected. SRCM 100731 was named as Bacillus amyloliquefaciens SRCM 100731 16S rRNA sequencing analysis, and carried out optimization of cell growth for industrial applications such as pet food and feed. The effects of 14 different components on cell growth were investigated and three significant positive factors, molasses, sodium chloride, and potassium chloride were selected as the main factors based on a Plackett-Burman design. In order to find out optimal concentration on each constituent, we carried out central composite design. The predicted optimized concentrations were 7% molasses, 1.1% sodium chloride, 0.5% potassium chloride. Finally, an overall about 7-fold increase in dry cell weight yield ($12.6625{\pm}0.0658g/L$) was achieved using the optimized medium compared with the non-optimized medium ($1.8273{\pm}0.0214g/L$). This research is expected to be highly utilized in the growing pet industry by establishing optimal cultivation conditions for industrial application as well as screening Bacillus amyloliquefaciens SRCM 100731 as probiotic resource for companion animal.

• Journal of Life Science
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• v.34 no.7
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• pp.465-475
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• 2024

Lactiplantibacillus plantarum K9 is a probiotic strain that can be utilized from various bioactive substances isolated from Protaetia brevitarsis seulensis larvae. In this study, a genetic analysis of L. plantarum K9 revealed the existence of a bacterial chromosome and three plasmids. The glycolysis pathway and pentose phosphate pathway were examined for their normal functioning via an analysis of the core metabolic pathways of L. plantarum K9. Since the key enzymes, fluctose-1,6-bisphospatase (EC: 3.1.3.11) and 6-phosphogluconate dehydratase (EC: 4.2.1.12)/2-keto-deoxy-6-phosphogluconate (KDPG) aldolase (EC: 4.2.1.55), of gluconeogenesis and the ED pathway were not identified from the L. plantarum K9 genome, we suggest that gluconeogenesis and the ED pathway are not performed in L. plantarum K9. Additionally, while some enzymes, related to fumarate and malate biosyntheses, involved in the TCA cycle were identified from L. plantarum K9, the enzymes associated with the remaining TCA cycle were absent, indicating that the TCA cycle cannot proceed. Meanwhile, based on our findings, we propose that the oxidative electron transport system performs class IIB-type (bd-type) electron transfer. In summary, we assert that L. plantarum K9 performs homolactic fermentation, executes gluconeogenesis and the pentose phosphate pathway, and carries out energy metabolism through the class IIB-type oxidative electron transport system. Therefore, we suggest that L. plantarum K9 has relatively high lactic acid production, and that it has excellent antibacterial activity, as a result, compared to other lactic acid bacterial strains. Moreover, we speculate that L. plantarum K9 has an oxidative electron transport capability, indicating that it is highly resistant to oxygen and suggesting that it has fine cultivation characteristics, which collectively make it highly suitable for use as a probiotic.