• Korean Journal of Microbiology
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• v.45 no.2
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• pp.193-199
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• 2009

A bacterium producing the halotolerant extracellular protease was isolated from squid jeotgal, and was identified as Bacillus sp. SJ-10 based on morphological, physiological and biochemical characteristics, as well as phylogenetic analysis using 16S rRNA gene sequence. The strain grew at $20^{\circ}C\sim55^{\circ}C$, pH 5~8, and 0%~14% NaCl and optimal growth conditions were $35{\pm}5^{\circ}C$, pH 7, and 5% NaCl. The major cellular fatty acids were anteiso-$C_{15:0}$, anteiso-$C_{17:0}$, and $C_{16:0}$ DNA G+C content was 50.58 mol% and menaquinone consisted of MK-7 Phylogenic analysis based on the 16S rRNA gene sequence indicated that SJ-10T belongs to the genus Bacillus. About 40 kDa of the salt-tolerant protease was purified by 40% ammonium sulfate saturation and Mono Q column chromatography. The optimal activity of the protease was pH 8 and stable at pH 5~10. The optimum temperature and NaCl concentration were $35{\pm}5^{\circ}C$ and $5{\pm}1%$, respectively.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.58-62
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• 2009

From the course of screening of useful enzyme producing microorganism from marine sedimentary layer, we isolated 2 lipase producing strains and their lipase producing activities were tested. 16S rDNA sequence analysis showed that they were Gram-positive bacteria grouped on Janibacter sp. An excellent lipase producing strain, Janibacter sp. LI-68 and J. sp. LI-80 identified by 16S rDNA analysis and biochemical methods (BIOLOG), was further studied its lipase producing characteristics. The optimum initial pH, temperature and the optimum cultral time for the enzyme production on MA medium were 8, $30{\sim}40^{\circ}C$ and 96 h, respectively.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.191-200
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• 2014

Gas hydrates play a significant role in the global carbon cycle and climate change because methane, a greenhouse gas, can be released from the dissociation of gas hydrate. Anaerobic oxidation of methane (AOM) is an important process that consumes more than 90% of the methane released into the hydrosphere and atmosphere. In this study, the microbial community associated with the methane gas hydrate sediment in the Ulleung basin, East Sea of Korea (UBGH) was analyzed by phylogenetic analysis of the mcrA and 16S rRNA gene libraries. A vertical stratification of the dominating anaerobic methane oxidizer (ANME)-1 group was observed at the surface and the sulfate methane transition zone (SMTZ). The ANME-2c group was found to be dominant in the high methane layer. The archaea of marine benthic group B, which is commonly observed in the AOM region, accounted for more than 50% of the identifications in all sediments. Nitrate reducing bacteria were predominant at SMTZ (Halomonas: 56.5%) and high methane layer (Achromobacter: 52.6%), while sulfate reducing bacteria were not found in UBGH sediments. These results suggest that the AOM process may be carried out by a syntrophic consortium of ANME and nitrate reducing bacteria in the gas hydrates of the Ulleung Basin of the East Sea.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.245-248
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• 2014

Pseudomonas syringae pv. actinidiae is the causal agent of bacterial canker in kiwifruit (genus Actinidia). Multilocus sequence analysis of seven housekeeping and 11 type III effector genes differentiated the virulent P. syringae pv. actinidiae isolates worldwide into three groups designated as Psa1-Psa3. In this work, a total of 12 P. syringae pv. Actinidiae strains, including three Psa1, three Psa2, three Psa3 strains isolated from Korea and three Psa3 strains from Italy, were compared based on their phenotypic properties. Strains with different geographic origins had unique growth patterns as demonstrated by growth rate at several temperatures; all tested strains exhibited maximum growth at temperatures below $22^{\circ}C$, while the growth of Psa3 strains was completely inhibited above $30^{\circ}C$. Psa3 strains isolated from Korea had longer lag phases than the Psa3 strains from Italy. The Psa2 strains were different from Psa1 and Psa3 strains in the API 20NE test, in which the Psa2 strains could not utilize potassium gluconate, capric acid and trisodium citrate. Psa3 strains isolated from Korea could hydrolyze esculin. The API ZYM test showed that ${\beta}$-glucosidase activity was detected only from Psa3 strains. The strains belonging to the three Psa groups differed with regard to their susceptibility to ampicillin, novobiocin, and oleandomycin.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.53-59
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• 2014

This study was conducted to investigate the characteristics between non-fermented chinese yam and rice (non-FCYR) and fermented chinese yam and rice (FCYR). 1.1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, total polyphenol, flavonoid contents and reducing power were investigated to evaluate the anti-oxidation activities of FCYR. Also, productivity of monacolin K, major medicinal ingredient of FCYR, was investigated, using Aspergillus terreus KCCM 12225. In case of non-FCYR, DPPH radical scavenging activities for three kinds of yam (Dioscorea japonica, Dioscorea batatas, Dioscorea opposita) and rice were estimated about 51.8, 66.4, 42.2 and 7.5%, while in case of FCYR, those for three kinds of yam and rice were estimated to increased about 64.7, 74.7, 52.8, and 32.3%, respectively. Total polyphenol contents of non-FCYR were estimated to 196.9, 265.7, 160.1, and 91.6 mg/kg, while total polyphenol contents of FCYR were estimated to increase about 530.7, 708.3, 427.2, and 265.9 mg/kg, respectively. Total flavonoid contents of FCYR increased to 2.8-3.3 times higher than those of non-FCYR. Reducing power of non-FCYR was about 0.97, 1.28, 0.64, and 0.17 (OD at 700 nm), while, that of FCYR increased about 1.75, 2.38, 1.24, and 0.46. Remakable increase in monacolin K productivity of FCYR was observed. Monacolin K productivity of FCYR was estimated to 467.1, 514.8, 339.2, and 272.5 mg/kg, respectively. In this study, fermented chinese yam (Dioscorea batatas) was estimated to be effective biological activity material.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.46-52
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• 2014

This study was carried out to investigate the characteristics of fermented chinese yam and rice (Dioscorea japonica, Dioscorea batatas, Dioscorea opposita, Rice, FCYR) using Monascus sp. MK805. The extracts from FCYR were measured to examine pigments, antioxidant activities were investigated through DPPH radical scavenging activity, total polyphenol and flavonoid contents, reducing power. Also it was investigated monacolin K productivity by FCYR. Pigments productivity (yellow, orange and red) were 26.2, 13.9, 17.3 at Dioscorea japonica, 41.9, 22.6, 53.2 at Dioscorea batatas, 12.5, 7.5, 9.7 at Dioscorea opposita and 10.1, 7.7, 10.2 at rice, respectively. DPPH radical scavenging activity of FCYR was about 69.7, 79.6, 57.8, and 42.3%, total polyphenol contents of FCYR was about 480.6, 658.7, 379.3, and 212.9 mg/kg, total flavonoid contents of FCYR was about 342.5, 448.4, 235.2, and 168.7 mg/kg, reducing power of FCYR was about 1.57, 2.14, 1.14, and 0.35 (OD at 700 nm), respectively. And then monacolin K productivity of FCYR was about 453.8, 509.5, 332.2, and 263.2 mg/kg, respectively.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.33-39
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• 2014

One hundred forty four bacterial colonies which were able to degrade crude oil were isolated from soil samples that were contaminated with oil in Daejeon area. Among them, one bacterial strain was selected for this study based on its emulsification activity, growth rate and surface tension activity, and this selected bacterial strain was identified as Pseudomonas sp. HN37 through physiological- biochemical tests and analysis of its 16S rRNA sequence. Pseudomonas sp. HN37 utilize the several aliphatic hydrocarbons, 3,5-dinitrosalicylic acid and 2,4-dichlorophooxyacetic acid as a sole carbon source. And this bacterial strain showed a high resistance to antibiotics such as ampicillin and chloramphenicol, as well as heavy metals such as Ba, Cr, Li and Mn. Also, it was found that the optimal pH and temperature for the cell growth, surface tension, and emulsification activity of Pseudomonas sp. HN37 were pH 6.0-9.0 and $30^{\circ}C$, respectively. The emulsification and surface tension activity was reached the maximum to 1% (V/V) crude oil and 1% (W/V) NaCl concentration. The surface tension of the culture broth was decreased from 62 to 27 dyne/cm after fifteen hours of inoculation in LB media.

• Korean Journal of Materials Research
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• v.12 no.12
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• pp.962-966
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• 2002

The $SrBi_2$$Nb_2$$O_{9}$ (SBN) thin films were deposited with $SrNb_2$$O_{6}$ / (SNO) and $Bi_2$$O_3$ targets by co-sputtering method. For the growth of SBN thin films, we adopted the various power ratios of two targets; the power ratios of the SNO target to $Bi_2$$O_3$ target were 100 W : 20 W, 100 W : 25 W, and 100 W : 30 W during sputtering the SBN films. We found that the electrical properties of SBN films were greatly dependent on Bi content in films. The $Bi_2$Pt and $Bi_2$$O_3$ phase as second phases occurred at the films with excess Bi content greater than 2.4, resulting in poor ferroelectric properties. The best growth condition of the SBN films was obtained at the power ratio of 100 W : 25 W for the two targets. At this condition, the crystallinity and electrical properties of the films were improved at even low annealing temperature as $700^{\circ}C$ for 1h in oxygen ambient and the Sr, Bi and Nb component in the SBN films were about 0.9, 2.4, and 1.8 respectively. From the P-E and I-V curves for the specimen, the remnant polarization value ($2P_{r}$) of the SBN films was obtained about 6 $\mu$C/c $m^2$ at 250 kV/cm and the leakage current density of this thin film was $2.45$\times$10^{-7}$ $A/cm^2$ at an applied voltage of 3 V.V.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.150-152
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• 2019

In this study, the effects of the wave field changes due to the coastal structure on the hydrodynamic performance of the OWC wave energy, converter are analyzed using a three-dimensional numerical wave tank technique (NWT). The OWC device is simulated numerically by introducing a linear pressure drop model, considering the coupling effect between the turbine and the OWC chamber in the time domain. The flow distribution around the chamber is different due to the change of reflection characteristics depending on the consideration of the breakwater model. The wave energy captured from the breakwater is spatially distributed on the plane of the front of the breakwater, and the converted pneumatic power increased when concentrated in front of the chamber. The change of the standing wave distribution is repeated according to the relationship between the incident wavelength and the length of the breakwater, and the difference in energy conversion performance of the OWC was confirmed.

• Korean Journal of Oriental Medicine
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• v.14 no.2
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• pp.107-112
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• 2008

Although the pulse diagnosis position, Guan is apart from Cun or Chi by only $10{\sim}20$ mm at most, traditional medical doctors applies different indent pressures and even they states different pulse images are felt at Cun, Guan and Chi, To support their clinical behaviors, in this study, we tested statistically whether there are differences in pulse waveform measured at these three positions with SphygmoCor system used world widely, A 30 years old female subject without any evidence of cardiovascular diseases was involved in this experiment. Radial pulse waves were recorded at three different positions on left lower arm 10 times at three positions-Cun, Guan and Chi. With ANOVA, we tested whether, among three different positions. there are any differences in 12 parameters of radial pulse waveform and in estimated AIx(Augmentation Index) as an arterial stiffness index extracted from radial pulse waveform. As results, differences in optimal indent pressure h0 were observed at different measuring positions(P<0.001) but not significantly different. And pulse pressure his were found to be different(Chi$22.60{\pm}3.06%,\;18.60{\pm}3.37%\;and\;26.4{\pm}5.02%$ respectively. Consequently. AIx at Gwan seems to be lowest and that at Chi seems to be highest. So. we assert the AIx at Chi is likely to be overestimated. In further studies. we want to examine what make differences in these parameters between measuring positions. And it also seems to be worthy to investigate the relationship between the depth of radial artery and AIx. And, ultimately, we need to determine the best measuring process including measuring position, hold-down pressure, signal quality validation and so on. so to achieve the optimal waveform which represents subject's health condition for both western medicine and traditional medicine.