• 한국환경복원기술학회지
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• 제27권2호
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• pp.43-53
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• 2024

This study attempted to elucidate the ecological niches and influencing environmental factors of Quercus variabilis and Quercus acutissima, which are representative deciduous broad-leaved trees in Korean forests, taxonomically close and genetically similar, under climate change conditions. Under climate change conditions induced by increased CO₂ and temperature, soil moisture and nutrient environments were manipulated in four gradients. At the end of the growing, plants were harvested to measure growth responses, calculate ecological niches, and compare them with those of the control. Eperimental plants were grown for 180 days in a glass greenhouse designed with four gradients each for soil moisture and nutrient environments under climate change conditions induced by increased CO₂ and temperature. After harvesting, growth responses of leaf traits were measured, ecological niches were calculated, and these were compared with those of the control groups. Furthermore, the responses of the two species' populations were interpreted using principal component analysis(PCA) based on leaf trait measurements. As a result, under climate change conditions, the ecological niche breadth for moisture environment was broader for Quercus variabilis than Quercus acutissima, whereas for the nutrient environment, Quercus acutissima exhibited a broader niche breadth than Quercus variabilis. And the rate of change in ecological niche breadth due to climate change decreased for Quercus variabilis in both moisture and nutrient environments, while for Quercus acutissima, it increased in the moisture environment but decreased in the nutrient environment. Additionally, in terms of group responses, both Quercus variabilis and Quercus acutissima expanded their ecological niches under climate change conditions in both soil moisture and nutrient conditions, with Quercus acutissima exhibiting a broader niche than Quercus variabilis under nutrient conditions. These results indicate that the changes in leaf morphological characteristics and the responses of individuals reflecting them vary not only under climate change conditions but also depending on environmental factors.

• 한국작물학회지
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• 제52권1호
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• pp.1-11
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• 2007

일사 저하에 따른 벼의 형태적 변화와 광합성 특성 변화를 평가하기 위하여, 필리핀 소재 국제미작연구소(IRRI)에서 3품종을 이용하여 분얼기, 생식생장기, 등숙기에 약 40% 차광 처리하고 자연광 처리를 두어 비교한 결과는 다음과 같다. 1. 차광 조건에서 벼는 단위 엽면적 및 엽록소계(SPAD) 측정값 증가, 엽신으로의 건물중 분배비율 증가 등 일조 부족에 대한 적응 형태를 나타내었으나, 분얼이 지연되고 건물 생산량이 감소하는 특징을 보였다. 2. 차광 조건에서 생육한 벼는 자연광 조건에서 생육한 벼에 비하여 탄소동화속도가 늦었으나 조직 내 이산화탄소의 농도는 높게 유지되어, 차광 내 벼의 광합성이 낮았던 것은 광합성 기질인 이산화탄소의 제한이 아니고 photosystem의 전자전달 활성의 약화에 기인된 것으로 판단되었다. 3. 차광 조건에서 생육한 벼를 자연광에 1일간 노출시켜 순화한 후 측정한 최대 광합성과 photosynthetic photon flux density에 대한 광합성 반응은 자연광에서 생육한 벼의 광합성 반응과 차이를 보이지 않아, 차광 조건에서 생육한 벼는 자연광에서 생육한 벼 수준의 잠재 광합성 능력을 유지하고 있었으며, 차광에서의 광합성 저하는 단순하게 일사량 저하에 의한 현상이었다. 4. 분얼기간 동안 차광 조건에서 생육하고 유수형성기 이후 자연광에 노출되어 생육한 벼는 자연광 조건에서 생육한 벼에 비하여 유수형성기부터 출수기까지의 SPAD 값의 증가 정도가 적으며, 엽신 질소 함량의 감소 정도가 크고, $2,000\;{\mu}mol\;m^{-2}s^{-1}$ 이상으로 강한 광 조건에서는 광합성이 감소하는 경향을 보여, 일조 부족에 적응한 벼는 photoinhibition 정도가 큰 것으로 생각된다. 5. 벼 수량은 자연광 처리에 비하여 유수형성기$\sim$출수기 차광에서는 수당영화수와 포트당 영화수의 감소에 의하여, 출수기$\sim$성숙기 차광에서는 등숙비율의 저하에 의하여 감소하였다.

• 한국습지학회지
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• 제15권2호
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• pp.171-177
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• 2013

한반도의 참나무 중 하천변 잠재자연식생인 졸참나무와 갈참나무를 대상으로 지구온난화의 핵심 요소인 $CO_2$농도와 온도를 상승시킬 때 잎의 형태학적 반응이 어떻게 일어나는지 알아보고자 유리온실 내에서 대기 중의 $CO_2$농도를 그대로 반영한 대조구와 이보다 $CO_2$농도는 약 1.6배와 온도는 $2.2^{\circ}C$상승시킨 온난화처리구에서 실험하여 관찰하였다. 그 결과, 졸참나무와 갈참나무는 $CO_2$농도와 온도의 상승으로 인하여 잎폭 길이, 잎몸 무게 그리고 엽면적이 증가하고 잎 수와 비엽면적은 감소하는 경향을 나타냈다. 졸참나무는 잎폭 길이, 잎몸 길이, 잎몸 무게, 잎 수, 엽면적 그리고 비엽면적 모두 대조구와 온난화처리구 간에 차이가 없었다. 그러나 갈참나무는 잎폭 길이와 잎몸 무게의 증가, 비엽면적의 감소가 뚜렷하였다. 이상의 잎의 형태학적 반응으로 볼 때, 갈참나무는 $CO_2$농도와 온도에 대하여 졸참나무 보다 민감하게 반응한다는 것을 알 수 있다. 주성분분석 결과, 두 종은 요인 1과 2에 의해 대조구와 온난화처리구에서 배열에 차이가 있었고, 온난화처리에 대한 변화는 졸참나무보다 갈참나무에서 명확히 구별되었다.

• The Korean Journal of Physiology
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• 제30권2호
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• pp.289-297
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• 1996

Excitatory amino acids (EAA) are thought to play an important role in producing cell death associated with ischemic and traumatic spinal cord injury. The present study was carried out to determine if the response characteristics of spinal sensory neurons in segments adjacent to degeneration sites induced by EAA are altered following these morphological changes. Intraspinal injections of quisqualic acid (QA) produced neuronal degeneration and spinal cavitation of gray matter. The severity of lesions was significantly attenuated by pretreatment with a non-NMDA antagonist NBQX. In extracellular single unit recordings, dorsal horn neurons in QA injected animal showed the increased mechanosensitivity, which included a shift to the left in the stimulus-response relationship, an increased background activity and an increase in the duration of after-discharge responses. Neuronal responses, especially the C-fiber response, to suprathreshold electrical stimulation of sciatic nerve also increased in most cases. These results suggest that altered functional states of neurons may be responsible for sensory abnormalities, e.g. allodynia and hyperalgesia, associated with syringomyolia and spinal cord injury.

• Korea-Australia Rheology Journal
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• 제11권4호
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• pp.321-328
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• 1999

This paper discusses the rheology of complex interfaces comprised of amphiphilic materials that are susceptible to flow-induced orientation and deformation. The consequence of the coupling of the film micro-structure to flow leads to nonlinear rheology and surface fluid dynamics. Experimental methods designed to determine the mechanical rheological material functions of fluid-fluid interfaces as well as local, molecular and morphological responses are presented. These include a newly developed interfacial stress rheometer, flow ultraviolet dichroism, and Brewster-angle microscopy. These techniques are applied to a number of complex interfaces ranging from low molecular weight amphiphiles to polymer monolayers. Nonlinear flow phenomena ranging from two-dimensional nematic responses to highly elastic surface flows that manifest surface normal stress differences and elongational viscosities are described.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.655-660
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• 1999

Sphingomyelinase (SMase EC:3.l.4.l2) has been suggested to play important roles in the cell cycle, differentiation, apoptosis, inflammation, and the regulation of eukaryotic stress responses. SMase inhibitors may be a powerful tool to elucidate and regulate these cellular responses in which SMase involves. We first isolated an SMase inhibitor, named sphinin, from a strain of soil actinomycetes, F50970. Sphinin inhibited Mg/sup 2+/ -dependent neutral SMase from chicken embryo at 1.2 ㎍/㎖ of IC/sub 50/ Sphinin also inhibited acidic SMase, but it had no inhibitory activity on PI-PLC and PC-PLC, suggesting that sphinin is a specific inhibitor of SMase. The strain F50970 was identified as a Streptomyces sp. by its spiral spore chain, LL-diaminopimelic acid, menaquinone patterns of MK-9 (H'6) and MK-9 (H'8), FA-2c type of fatty acid pattern, and other morphological, physiological, and cultural characteristics.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.220.3-220
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• 2005

• Journal of Ginseng Research
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• 제33권4호
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• pp.330-336
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• 2009

G-Rb1에 의한 단핵구 세포주인 U937 세포와 대식세포주인 RAW264.7 세포의 유착조절 능, 세포표면 단백질 발현율 및 세포모양 변화능 조절효과를 조사하여 다음과 같은 결론을 얻었다. 1. G-Rb1은 CD29항체 (MEM101A) 및 CD43 항체(161-46) 처리에 의해 유도된 세포-세포간 유착현상을 20%에서 35%까지 유의적으로 상승하였다. 2. G-Rb1은 fibronectin처리에 의해 유도된 U937 세포-fibronectin간 유착현상을 상승시켰다. 3. G-Rb1은 CD29 및 CD43의 세포표면 발현 수준을 유의적으로 증가시켰으나 CD82의 발현은 억제시켰다. 4. G-Rb1은 PMA에 의해 유도된 형태변화는 촉진경향을 반면에 LPS에 의한 변화는 억제경향을 나타내었다. 인삼의 주요사포닌 성분인 G-Rb1의 약리작용이 활발히 연구되고 있다. 특별히, 본 화합물이 갖는 면역증강 및 항암 효능은 인삼이 갖는 이들 효과를 대신하는 것으로 보고 되어져 있다. 그러나, 세포유착과정이 다양한 염증과정, 알러지 반응 및 암세포의 이동과 전이성 등에 관련이 있다는 관점에서 볼 때 본 연구결과는 이들 약물이 갖는 치료기전을 설명하기에는 충분하지 않는 것으로 판단된다. 오히려, 본 결과는 G-Rb1이 특정 농도 ($25-50\;{\mu}M$ 수준)에서 세포의 활성을 촉진할 수 있다는 가능성을 시사한다고 하겠다. 특별히, G-Rb1의 세포유착 촉진 기능에 관한 기전 이해를 위해, 이후, 세포유착 유도 신호전달 단백질의 활성을 포함한 다양한 분자적 수준에서의 추가적인 실험들을 진행하고 한다.

• Journal of Photoscience
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• 제7권4호
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• pp.161-167
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• 2000

Temperature-dependent electroretinogram responses were investigated in the dark adapted bullfrog eyes within the physiological temperature range 0-40$\^{C}$. In hypothermic process(25→0→25$\^{C}$), the amplitude of b-and c-wave decreased with lowering the temperature again. Both b-wave amplitude and threshold responses were maximal around 15$\^{C}$ during the temperature increment. Upon warming to room temperature again (25$\^{C}$), the b-wave amplitude was approximately doubled as compared to that of control without temperature changes. During the hyperthermic process (25→40→25$\^{C}$), however, the responses decreased with warming, and the wave amplitude failed to recover by cooling to 25$\^{C}$ again. As describe above, the recoveries of ERG in both processes show the striking difference. The hypothermia induces the amplification of the b-wave, that is, enhances the retinal function with the temperature recovery toward room temperature. While the hypertherima produces the decrease of the b-wave even though recovered to room temperature, which indicates an irreversible retina. The morphological alteration is shown both hypothermic and hyperthermic process, such as an appearance of large vacuoles and degenerating outer segments, more intense in hyperthermia, similar to light induced damage.

• The Korean Journal of Physiology and Pharmacology
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• 제21권4호
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• pp.449-456
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• 2017

Beauvericin (BEA), a cyclic hexadepsipeptide produced by the fungus Beauveria bassiana, is known to have anti-cancer, anti-inflammatory, and anti-microbial actions. However, how BEA suppresses macrophage-induced inflammatory responses has not been fully elucidated. In this study, we explored the anti-inflammatory properties of BEA and the underlying molecular mechanisms using lipopolysaccharide (LPS)-treated macrophage-like RAW264.7 cells. Levels of nitric oxide (NO), mRNA levels of transcription factors and the inflammatory genes inducible NO synthase (iNOS) and interleukin (IL)-1, and protein levels of activated intracellular signaling molecules were determined by Griess assay, semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), luciferase reporter gene assay, and immunoblotting analysis. BEA dose-dependently blocked the production of NO in LPS-treated RAW264.7 cells without inducing cell cytotoxicity. BEA also prevented LPS-triggered morphological changes. This compound significantly inhibited nuclear translocation of the $NF-{\kappa}B$ subunits p65 and p50. Luciferase reporter gene assays demonstrated that BEA suppresses MyD88-dependent NF-${\kappa}B$ activation. By analyzing upstream signaling events for $NF-{\kappa}B$ activation and overexpressing Src and Syk, these two enzymes were revealed to be targets of BEA. Together, these results suggest that BEA suppresses $NF-{\kappa}B$-dependent inflammatory responses by suppressing both Src and Syk.