• Journal of Life Science
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• v.28 no.10
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• pp.1179-1185
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• 2018

Recently, Sargassum horneri, the marine weed inhabiting the shoreline, beach, and littoral sea area, has caused serious damage to intensive aquaculture farms particularly those around Jeju Island, South Korea. The purpose of this study was to investigate the diversity of microorganisms in Sargassum horneri and to provide basic data on ecological problems by identifying microbial functions. A total of 88 isolates were identified by 16S rRNA sequencing. Proteobacteria was the dominant phylum accounting for 88%, including class ${\alpha}-proteobacteria$, six genera, and ten species. The dominating genus, Pseudobacter, accounted for 40% in Pseudorhodobacter, 20% in Paracoccus, and the remaining at 10% each were Rhizobium, Albirhodobacter, Skermanella, and Novosphingobium. Class ${\beta}-proteobactera$ included five genera and ten species. Genus Hydrogenophaga accounted for 50%, while genus Azoarcus accounted for 20%, and the remaining Oxalicibacterium, Duganella, and Xenophilus were 10% each. Class ${\gamma}-proteobacteria$ with 13 genera and 57 species, accounted for 74% in phylum Proteobacteria, 23% in Shewanella, 19% in Cobetia, 12% in Pseudomonas, 4% each in Vibrio and Serratia, and 2% each in Rheinheimera, Raoultella, Pantoea, Acinetobacter, Moraxella, and Psychrobacter genera. In addition, Actinobacteria with two species of Nocardioides genera accounted for 50%, and Bacteroidetes accounted for 33%, with three genera and five species that included Lacihabitans and Mariniflexile. The remaining Dyadobacter, Cellulophaga, and Ferruginibacter genera each accounted for 11%.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.39-45
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• 2016

Pink Rot on melon and White Stain Symptom on grape are caused by Trichothecium roseum, one of the most important diseases of grape and melon. These diseases have been occurred in national-wide in Korea and causes irreversible damage on the grape and the melon at harvest season. This research presents the evaluation of the capacity of Bacillus subtillis HK2 to protect both melon and grape against T. reseum and establishes its role as a biocontrol agent. In this study, we isolated a Bacillus strain HK2 from rhizosphere soil, identified it as Bacillus subtillis by 16S rRNA analysis and demonstrated its antifungal activity against T. roseum. Under I-plate assay it was observed that the effect of hyphal growth inhibition was not due to production of volatile compounds. The optimum culture condition of HK2 was found at 30℃ and initial pH of 7.0. Application of HK2 culture suspension reduced 90.2% of white stain symptom on grape as compared to control, resulting in greater protection to grape against T. roseum infestation. Butanol extract of HK2 culture purified using flash column chromatography. The antifungal material was a polar substance as it showed antifungal activity in polar elute. Therefore, our results indicated a clear potential of B. subtilis HK2 to be used for biocontrol of Pink rot in melon and white stain symptom on grape caused by T. roseum.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.448-454
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• 2010

This study investigated the effect of PCE and TCE as electron acceptors on the bacterial composition of dechlorinating communities. The enrichment cultures reductively dechlorinating PCE and TCE were developed from three environment samples using acetate as electron donor. The cultures were prepared by sequential enrichment, which was seeded with sediment and dredged soil. Denatured gradient gel electrophresis (DGGE) of 16S rRNA gene fragment was used to compare the microbial communities of these three enrichment cultures. After incubation for 4 weeks, the removal efficiencies of PCE and TCE were highest from Yeocheon site (87.37% and 84.46%, respectively). PCE and TCE as electron acceptors affected the bacterial diversity and community profiles in the enrichment cultures. DGGE analysis showed that the dominant bacteria in PCE and TCE enrichment were belonged to Clostridium sp., Desulfotomaculum sp., and uncultured bacteria.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.407-412
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• 2014

A number of Saccharomycopsis fibuligera strains that can hydrolyse and utilize starch as a carbon source were isolated from nuruk, a traditional Korean starter for rice wine fermentation, and their specific growth rates on starch-containing medium were compared to choose the prominent strain. S. fibuligera strain MBY1320 showed a higher growth rate at $42^{\circ}C$ than that of strain S. fibuligera KCTC7806, indicating that S. fibuligera MBY1320 has more thermo-tolerant machinery for starch hydrolysis and utilization than KCTC7806. Although the activity of ${\alpha}$-amylase at $30^{\circ}C$ was significantly lower for S. fibuligera MBY1320 than KCTC7806 (3,812.5 U vs. 14,878.5 U), S. fibuligera MBY1320 showed a much higher glucoamylase activity at $42^{\circ}C$ than S. fibuligera KCTC7806 (5,048.9 U vs. 13,152.3 U). Thus, a new S. fibuligera strain, with a higher starch-hydrolysing activity at elevated temperatures than that of other types of strain, this study reports.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.264-271
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• 2013

Mating system parameters were estimated in a natural population of Pinus koraiensis which was located at Gwongeumseong in Mt. Seorak, South Korea. The estimated parameters from allozyme were as follows: 0.882 of multilocus outcrossing rates($t_m$), 0.881 of singlelocus outcrossing rates($t_s$), 0.368 of correlated paternity($r_p$), and 2.7 of number of effective pollen contributors. The estimated parameters from cpSSR markers were as follows: 0.831 of average of outcrossing rates and 12.4 of the average number of effective pollen contributors. The average outcrossing rate from two genetic markers was 0.857, which was similar to those estimated in other conifer species. More number of potential pollen contributors was estimated from cpSSR marker analysis compared with that estimated from allozyme marker analysis. This result sugges$t_s$ that cpSSR markers may be more useful than allozyme markers for identifying potential pollen contributors in the analysis of mating system.

• Journal of Ginseng Research
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• v.44 no.2
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• pp.341-349
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• 2020

Background: The replicative senescence of human dermal fibroblasts (HDFs) is accompanied by growth arrest. In our previous study, the treatment of senescent HDFs with Rg3(S) lowered the intrinsic reactive oxygen species (ROS) levels and reversed cellular senescence by inducing peroxiredoxin-3, an antioxidant enzyme. However, the signaling pathways involved in Rg3(S)-induced senescence reversal in HDFs and the relatedness of the stereoisomer Rg3(R) in corresponding signaling pathways are not known yet. Methods: We performed senescence-associated β-galactosidase and cell cycle assays in Rg3(S)-treated senescent HDFs. The levels of ROS, adenosine triphosphate (ATP), and cyclic adenosine monophosphate (cAMP) as well as the mitochondrial DNA copy number, nicotinamide adenine dinucleotide (NAD)⁺/1,4-dihydronicotinamide adenine dinucleotide (NADH) ratio, and NAD-dependent sirtuins expression were measured and compared among young, old, and Rg3(S)-pretreated old HDFs. Major signaling pathways of phosphatidylinositol 3-kinase/Akt, 5' adenosine monophosphate-activated protein kinase (AMPK), and sirtuin 1/3, including cell cycle regulatory proteins, were examined by immunoblot analysis. Results: Ginsenoside Rg3(S) reversed the replicative senescence of HDFs by restoring the ATP level and NAD⁺/NADH ratio in downregulated senescent HDFs. Rg3(S) recovered directly the cellular levels of ROS and the NAD⁺/NADH ratio in young HDFs inactivated by rotenone. Rg3(S) mainly downregulated phosphatidylinositol 3-kinase/Akt through the inhibition of mTOR by cell cycle regulators like p53/p21 in senescent HDFs, whereas Rg3(R) did not alter the corresponding signaling pathways. Rg3(S)-activated sirtuin 3/PGC1α to stimulate mitochondrial biogenesis. Conclusion: Cellular molecular analysis suggests that Rg3(S) specifically reverses the replicative senescence of HDFs by modulating Akt-mTOR-sirtuin signaling to promote the biogenesis of mitochondria.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.311-316
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• 2008

In this study, biological PCE degradation by using a BTEX degrading bacterium, named BJ10, under aerobic conditions in the presence of toluene was examined. According to morphological, physiological characteristics, 16S rDNA sequencing and fatty acid analysis, BJ10 was classified as Pseudomonas putida. As a result of biological PCE degradation at low PCE concentrations (5 mg/L), PCE removal efficiency by P. putida BJ10 was 52.8% for 10 days, and PCE removal rate was 5.9 nmol/hr (toluene concentration 50 mg/L, initial cell density 1.0 g (wet weight)/L, temperature 30, pH 7 and DO $3.0{\sim}4.2\;mg/L$. At high PCE concentration (100 mg/L), PCE removal efficiency by P. putida BJ10 was 20.3% for 10 days, and PCE removal rate was 46.0 nmol/hr under the same conditions. The effects of various toluene concentration (5, 25, 50, 100, 200 mg/L) on PCE degradation were examined under the same incubation conditions. The highest PCE removal efficiency of PCE was 57.0% in the initial PCE concentration of 10 mg/L in the presence of 200 mg/L toluene for 10 days. Furthermore, the additional injection of 5.5 mg/L PCE (total 7.6 mg/L) made 63.0% degradation for 8 days in the presence of 50 mg/L toluene under the same conditions. Its removal rate was 13.5 nmol/hr, which was better than the initial removal rate (8.1 nmol/hr).

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.377-382
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• 2003

Purification of methioninase resulted in a yield of 69%, and SDS-PAGE analysis of the purified product revealed a single band of approximately 43 kDa in molecular weight. in vitro experiments with cancer cells incubated in methionine-free media demonstrated an increase in $^{11}$ C-methionine uptake to 25.8$\pm$1.1% at 6 hr, 31.8$\pm$0.8% at 24 hr, and 62.2$\pm$0.6% at 48hr, compared to controls. Treatment of the cancer cells with purified methioninase showed no decrease in survival after a 2 hr incubation with 0.01 U/ml, but survival of RR1022 cells decreased 30% after 24 to 48 hr incubation. SKOV-3 cells showed a 5% and 14% decrease in survival with 0.1 and 1 U/ml methioninase after 24 hr. After 48hr survival decreased 15% and 24% with 0.1 and 1 U/ml methioninase. Measurements of $^{11}$ C-methionine uptake in RR1022 cells demonstrated no change at 2 hr, but a 13.7$\pm$4.7% and 40.7$\pm$2.6% increase in uptake at 24 and 48 hr, respectively. SKOV-3 cells also showed no change at 2 hr, but had a 17.7$\pm$7.2% and 38.9$\pm$4.9% increase in $^{11}$ C-methionine uptake after 24 hr and 48 hr treatment with methioninase, respectively. $^{11}$ C-methionine PET imaging revealed clear visualization of both the tumors and contralateral infectious lesions. Administration of rMET appeared to result in a slight increase in tumor:nontumor contrast on $^{11}$ C-methionine PET images. Injection of purified methioninase also produced PET images where tumor uptake was higher than that of infectious lesions.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.69-70
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• 2018

Erwinia pyrifoliae is a Gram-negative bacterium causing black shoot blight in apple and Asian pear trees. E. pyrifoliae strain EpK1/15 was isolated in 2014 from an apple twig from the Pocheon, Gyeonggi-do, South Korea. In this study, we report the draft genome sequence of E. pyrifoliae EpK1/15 using PacBio RS II platform. The draft genome is comprised of a circular chromosome with 4,027,225 bp and 53.4% G + C content and a plasmid with 48,456 bp and 50.3% G + C content. The draft genome includes 3,798 protein-coding genes, 22 rRNA genes, 77 tRNA genes, 13 non-coding RNA genes, and 231 pseudo genes.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.59-67
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• 2002

A phosphate solubilizing bacterium. strain 60-2G, possessing a strong ability to solubilize insoluble phosphate was isolated from the rhizosphere of grass. On the basis of GC-FAME profile, carbon utilization pattern, and the DNA sequence of a conserved partial 16S rRNA gene, the 60-2G was identified as Enterobacter intermedium. The analysis by HPLC revealed that the strain 60-2G produced mainly gluconic and 2-ketogluconic acids with small amounts of lactic acid in broth culture medium containing hydroxyapatite. During the incubation period of the strain 60-2G in broth culture, pH of the medium decreased upto 3.8 while the soluble phosphate concentration increased. The reversed correlation between pH and soluble phosphate concentration indicated that the solubility of P was due to the produced organic acids. The sequence homology of the deduced amino acids suggested that E. intermedium 60-2G synthesized PQQ which is essential for the oxidation of glucose by glucose dehydrogenase.