• Journal of Microbiology and Biotechnology
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• 제34권9호
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• pp.1819-1825
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• 2024

An aerobic, Gram-stain-negative, catalase-positive, rod-shaped, and motile bacteria, designated as a strain WR6^T was isolated from soil in Republic of Korea. Strain WR6^T grew at temperatures of 10-37℃, at pH of 5.0-9.0, and at NaCl concentrations of 0-3.0% (w/v). Phylogenetic and 16S rRNA gene nucleotide sequence analysis confirmed that strain WR6^T affiliated to the genus Mesorhizobium, with the nearest relative being Mesorhizobium waimense ICMP 19557^T (98.5%). The genome of strain WR6^T was 5,035,462 bp with DNA G+C content of 62.6%. In strain WR6^T, Q-10 was sole ubiquinone; summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and C_19:0 cyclo ω8c were predominant fatty acids; and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine, and phosphatidylethanolamine were major polar lipids. Based on these polyphasic taxonomic data, strain WR6^T represents a novel species in the genus Mesorhizobium. Accordingly, we propose the name Mesorhizobium koreense sp. nov., with the type strain WR6^T (=KCTC 92695^T =NBRC 116021^T).

• 한국지구과학회지
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• 제45권2호
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• pp.121-135
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• 2024

1991-2020년의 30년 동안 봄철(3-5월)에 북극-동아시아 지역의 지표면 부근 대기 온난화가 북극 진동에 따라 한국의 서울에서 발생하는 황사 사례일의 종관 기상 특성에 미치는 영향을 분석하였다. 북극-동아시아 지역의 봄철 온난화 증가는 한국의 서울에서 황사 사례일을 6일을 감소시켰고, 황사 사례일의 PM₁₀ 질량 농도도 -1.6 ㎍ m^-3yr^-1으로 강도를 약화시키는데 기여하고 있었다. 2010년대 한국에서 감소하고 있는 황사 사례일에 대한 동아시아 지역의 종관 기상 특성은 음(-)의 잠재소용돌이도(Potential Vorticity Unit; PVU)로 나타나는 고기압성 활동이 증가하고 있었다. 또한, 한국에서는 음(-)의 북극진동지수(Arctic Oscillation Index; AOI)에서 황사 사례일이 증가하고 양(+)에서는 감소하는 정적 편포를 보였다. AOI가 음(-)인 황사 사례일에서는 중국 대륙에 온난한 고기압이 강화되고 있었다. 더불어 한대 제트의 중심 위치가 북쪽으로 이동하면서 몽골과 중국 북부에서는 한대 기단의 남하에 의한 저기압성 활동이 약해지고 있었다. 황사의 발생이 감소하였을 뿐 아니라 발원지로부터 한국으로 황사를 수송하는 풍속이 감소하고 있었다. 반면, AOI가 양(+)인 황사 사례일에서는 중국 대륙에 광역적으로 온난하고 정체적인 고기압이 위치하고 있었으며, 한대 제트의 북쪽이 더욱 냉각되어 있었다. 몽골-중국 북부-한국에 이르는 지역에서 하층 대류권의 현저한 풍속 감소가 황사 발생을 감소시킬 뿐 아니라 장거리 수송을 약화시키는 원인이 되는 것으로 보인다.

• 한국미생물·생명공학회지
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• 제45권2호
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• pp.168-177
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• 2017

Strain A28-5는대한민국 제주도 연안의 해수샘플로부터 고체배지내 xylan과 agar를 분해하는 균주로 분리되었다. Strain A28-5는그람 음성균으로 한 개의 polar flagella로 운동성을 갖는 $Na^+$ 이온 요구성 균주로 분석되었다. 또한 ampilcillin과 thiostreptone 등의 항생제에 내성을 보였다. Genome 내 G+C content는 43.96%이고, Menaquinone-7 (MK-7)을 predominant quinone으로 함유하고 있었다. Strain A28-5의 세포벽을 구성하는 주요 지방산은 $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), $C_{18:1}$ ${\omega}7c$ (17.98%)였다. strain A28-5의 16S rRNA gene sequence는 Catenovulum agarivorans YM01와 가장 높은 상동성(98.94%)을 보였으며, Neighbor-Joining phylogenetic tree 제작을 통해서 Catenovulum agarivorans YM01와 가장 높은 근연관계를 보이는 것을 증명하였다. Catenovulum agarivorans YM01과의 DNA-DNA hybridization 분석을 통하여 A28-5을 Catenovulum 속의 신종으로 분류하여Catenovulum jejuensis A28-5로 명명하였다. 이 균주의 액체배양으로부터 준비된 두 종류의 조효소를 이용한 xylan 또는 agarose와의 효소반응액을 Thin layer chromatography로 분석하여 각각 tetramer와 hexamer의 xylooligosaccharides와 (neo)agarooligosacchardes가 생산되는 것을 확인하였다.

• 대한화학회지
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• 제35권4호
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• pp.343-349
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• 1991

CHCl$_3$, CHCl$_3$ : CH$_2$Cl$_2$(1:1) 및 CH$_2$Cl$_2$ 용매 중에서 치환 aniline[aniline, N,N-dimethylaniline(N,N-DMA), 2,6-dimethylaniline(2,6-DMA) 및 2,4,6-trimethylaniline(2,4,6-TMA)]과 iodine간의 charge transfer complex 형성에 대하여 전도도법을 이용하여 속도론적으로 조사하였다. 초기에 일시적으로 생성된 outer charge transfer complex가 inner complex로 변환되는 과정에 있어서 치환 aniline의 electron donor 및 polar medium으로서의 작용에 대하여 고찰해 보았다. 또한 변환의 빠르기는 medium의 dielectric environment와 치환 aniline의 pK$_a$값에 의존하였으며 2,4,6-TMA, 2,6-DMA, aniline, N,N-DMA의 순서로 증가하였다. Chloroform 용매 중에서 2.5M 농도의 치환 aniline에 대해서 얻은 ${\Delta}H^{\neq}$값은 N,N-DMA, 3.47kcal/mol:aniline, 4.25kcal/mol:2,6-DMA, 7.79kcal/mol:2,4,6-TMA, 7.96kcal/mol:${\Delta}S^{\neq}$값은 모든 aniline에 있어서 -41~-55cal/mol${\cdot}$K의 큰 음의 값을 나타내었다.

• Journal of Plant Biology
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• 제28권2호
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• pp.165-175
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• 1985

지리산 피아골의 식생은 식물사회학적 방법에 의해 개서나무군낙, 서나무군낙, 신갈나무군낙, 졸참나무군낙, 들메나무군낙, 철쭉-진달래 관목림으로 분류되며, DBH-class 분포에 의하면 개서나무군낙, 서나무군낙, 신갈나무군낙은 모두 안정된 극상림인 것으로 보인다. 신갈나무군낙의 종다양도는 제일 낮고 우점도는 제일 높게 나타났으며, 토양조건은 서나무군낙이 신간나무군낙에 비해 습하고 비옥한 것으로 나타났다. 서나무군낙과 신갈나무군낙의 점이대는 DBH-class 분포로 보아 현재의 900∼1,000m 에서 1,000∼l,100까지 이동할 것으로 예측된다. Polar Ordination에 의한 식생형의 분류는 식물사회학적 방법의 결과와 일치했다. 고도구배를 따라 개서나무는 500∼700m, 서나무는 700∼900m, 신갈나무는 900m이상에서 최고의 중요치를 나타낸다. Raunkiaer의 life-form spectrum을 남한의 것과 비교하면, 반지중식물은 5.3%, 지중식물은 5.2% 높게 나타났으며, 착생식물과 수중식물은 극히 적게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권8호
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• pp.1112-1121
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• 2019

Objective: Gram-negative bacteria lipopolysaccharide (LPS) has been reported to be associated with uterine impairment, embryonic resorption, ovarian dysfunction, and follicle retardation. Here, we aimed to investigate the toxic effects of LPS on the maturation ability and parthenogenetic developmental competence of bovine oocytes. Methods: First, we developed an in vitro model to study the response of bovine cumulusoocyte complexes (COCs) to LPS stress. After incubating germinal vesicle COCs in $10{\mu}g/mL$ of LPS, we analyzed the following three aspects: the expression levels of the LPS receptor toll-like receptor 4 (TLR4) in COCs, activities of intracellular signaling protein p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-${\kappa}B$); and the concentrations of interleukin (IL)-$1{\beta}$, tumor necrosis factor (TNF)-${\alpha}$, and IL-6. Furthermore, we determined the effects of LPS on the maturation ability and parthenogenetic developmental competence of bovine oocytes. Results: The results revealed that LPS treatment significantly elevated TLR4 mRNA and protein expression levels in COCs. Exposure of COCs to LPS also resulted in a marked increase in activity of the intracellular signaling protein p-p38 MAPK and NF-${\kappa}B$. Furthermore, oocytes cultured in maturation medium containing LPS had significantly higher concentrations of the proinflammatory cytokines IL-$1{\beta}$, TNF-${\alpha}$, and IL-6. LPS exposure significantly decreased the first polar body extrusion rate. The cytoplasmic maturation, characterized by polar body extrusion and distribution of peripheral cortical granules, was significantly impaired in LPS-treated oocytes. Moreover, LPS exposure significantly increased intracellular reactive oxygen species levels and the relative mRNA abundance of the antioxidants thioredoxin (Trx), Trx2, and peroxiredoxin 1 in oocytes. Moreover, the early apoptotic rate and the release of cytochrome C were significantly increased in response to LPS. The cleavage, morula, and blastocyst formation rates were significantly lower in parthenogenetically activated oocytes exposed to LPS, while the incidence of apoptotic nuclei in blastocysts was significantly increased. Conclusion: Together, these results provide an underlying mechanism by which LPS impairs maturation potential in bovine oocytes.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3285-3292
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• 2012

The interaction of thiazole drug with (6,0) zigzag single-walled boron nitride nanotube of finite length in gas and solvent phases was studied by means of density functional theory (DFT) calculations. In both phases, the binding energy is negative and presenting characterizes an exothermic process. Also, the binding energy in solvent phase is more than that the gas phase. Binding energy corresponding to adsorption of thiazole on the BNNT model in the gas and solvent phases was calculated to be -0.34 and -0.56 eV, and about 0.04 and 0.06 electrons is transferred from the thiazole to the nanotube in the phases. The significantly changes in binding energies and energy gap values by the thiazole adsorption, shows the high sensitivity of the electronic properties of BNNT towards the adsorption of the thiazole molecule. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of LUMO, electron density, and length of the surrounding bonds of adsorbing atoms help to the thiazole adsorption on the nanotube. Decrease in global hardness, energy gap and ionization potential is due to the adsorption of the thiazole, and consequently, in the both phases, stability of the thiazole-attached (6,0) BNNT model is decreased and its reactivity increased. Presence of polar solvent increases the electron donor of the thiazole and the electrophilicity of the complex. This study may provide new insight to the development of functionalized boron nitride nanotubes as drug delivery systems for virtual applications.

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1207-1210
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• 2003

The effect of solvent structure on the slope in the plot of ln K vs. solute carbon number was examined. It was found that the free energy of methylene group transfer from the gas phase into a solvent was always negative and that the absolute magnitude of interaction free energy between the methylene group and the solvent was always larger than the absolute magnitude of cavity formation free energy of the methylene group in the solvent. Thus, the slope in the plot of ln K vs. solute carbon number was always positive and its value decreases with increase of solvent polarity since the cavity formation energy of the CH₂ unit increases with increase of solvent polarity while the dispersive interaction energy of the CH₂ unit is virtually invariant. We also examined the effect of sequential addition of CH₂ unit to a solvent molecule upon ln K for three homologous series of solvents: n-alkanes, n-alcohols, and n-nitriles. Characteristic trends in the plots of ln K vs. solvent carbon number were observed for individual solvent groups. A decrease of ln K with solvent carbon number was observed for n-alkanes. An abrupt increase in ln K followed by levelling off was observed for n-alcohols while a final slight decrease in ln K after an abrupt increase followed by rapid levelling off was noted for n-nitriles. All of theses phenomena were found related to variation in cavity formation energy. It was clearly shown that a structural change of a polar solvent by sequential addition of CH₂ units causes an abrupt polarity decrease initially, then gradual levelling off, and finally, conversion to a virtually nonpolar solvent if enough CH₂ units are added.

• 한국재료학회지
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• 제11권7호
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• pp.599-602
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• 2001

전도성 고분자인 poupyrrole과 polyaniline을 이용하여 센서를 제조하고 휘발성 유기화합물에 대한감응특성 및 감지막의 물성을 조사하여 지금까지 알려지지 않은 감응 기구를 설명하고자 하였다. Polypyrrole과 polyaniline은 두께가 얇은 경우가 두꺼운 경우보다 감도가 높았으며, 1분간 도펀트를 제거한 센서가 가장 높은 감도를 나타내었다. 또한 두 가지 센서 모두 극성이 강한 분자가 흡착될수록 감도가 증가하였는데, 이는 극성을 갖는 분자가 감지막 내부로 침투하여 polaron 및 자유 carrier를 고착시키거나 추가의 자유 carrier를 형성하여 전도도에 변화를 주기 때문인 것으로 판단된다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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• pp.26.3-27
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• 2011

Formation of a steep plasma density gradient in the middle-latitude ionosphere during geomagnetic storms and the latitudinal migration of its location depending on the storm phase are suggested to be associated with the ionospheric signature of the plasmapause. We test this idea by using the satellite and ground observation data during the 11 April 2001 storm. The locations of the steep plasma density gradient identified by TOPEX/Poseidon (2001 LT) and DMSP (1800 and 2130 LT) satellites coincide with the ionospheric footprints of the plasmapause identified by the IMAGE satellite. This observation may support the dependence of the middle-latitude plasma density gradient location on the plasmapause motion, but does not explain why the steep density gradient whose morphology is largely different from the morphology of the middle-latitude ionization trough during quiet period is formed in association with the plasmapause. The ionospheric disturbances in the total electron content (TEC) maps shows that the steep TEC gradient is formed at the boundary of the positive ionospheric storm in low-middle latitudes and the negative ionospheric storm in middle-high latitudes. We interpret that the thermospheric neutral composition disturbance in the dayside is confined within the middle-high latitude ionospheric convection zone. The neutral composition latitudes and, therefore, the locations of the steep plasma density gradient coincide with the footprints of the plasmapause. The TEC maps show that the appearance of the steep plasma density gradient in the pre-midnight sector during the recovery phase is related to the co-rotation of the gradient that is created during the main phase.