• 제목/요약/키워드: Fluorescence life times

검색결과 28건 처리시간 0.029초

Real Time Measurement of Protease Activity of Live Uronema marinum (Ciliata: Scuticociliatida) by Fluorescence Polarization Assay

  • Lee Eun Hye;Kwon Se Ryun;Kim Chun Soo;Chung Joon Ki;Lee Hyung Ho;Kim Ki Hong
    • Fisheries and Aquatic Sciences
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    • 제5권4호
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    • pp.311-313
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    • 2002
  • Proteolytic activity of live Uronema manum was analyzed by fluorescence polarization (FP) technique. Protease activity was measured by a decrease in FP value using fluorescein isothiocynate (FITC)-casein as a protein substrate. The results demonstrated an inverse linear relationship between fluorescence polarization (FP) values and live ciliate concentration over the range $1\times10^4\;to\;2\times10^5$ cells/well. However, the FP values of $10-10^3$ live parasites were not different significantly from that of control. Time-dependent decrease in FP value was shown in the wells containing live U. marinum. In the present study, FP assay had the benefit to provide measurements of substrate hydrolysis by live parasites in real-time, and did not require separations, precipitations, or transfers of reaction mixture.

Diffusion Coefficients of CdSe/CdS Quantum Rods in Water Measured Using Polarized Fluorescence Correlation Spectroscopy

  • Lee, Jaeran;Pack, Chan-Gi;Kim, Soo Yong;Kim, Sok Won
    • Journal of the Optical Society of Korea
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    • 제18권5호
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    • pp.598-604
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    • 2014
  • A polarization fluorescence correlation spectroscopy system based on a confocal microscope was built to study the rotational and translational diffusion of CdSe/CdS quantum rods (Q-rods), with the same and different polarization states between the polarizer and the analyzer (i.e. the XXX and XYY states). The rotational diffusion amplitude showed the dependences on polarization of $0.75{\pm}0.05$ in the XXX state and $0.26{\pm}0.03$ in the XYY state, when the translational diffusion amplitude was 1. The diffusion coefficients of the Q-rods were found based on their translational and rotational diffusion times in the two polarization states, in solutions with viscosity ranging from 0.9 to 6.9 cP. The translational and rotational diffusion coefficients ranged from $1.5{\times}10^{-11}$ to $2.6{\times}10^{-12}m^2s^{-1}$ and from $2.9{\times}10^5$ to $5.6{\times}10^4s^{-1}$, respectively.

나프탈이미도프로필 아크릴레이트와 GMA 공중합체의 합성과 물성 (Synthesis of Naphthalimidopropyl Acrylate and GMA Copolymers and Their Physical Properties)

  • 임덕점;오승민;김부윤;박재경;강인규;서관호;오대희
    • 폴리머
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    • 제38권4호
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    • pp.535-543
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    • 2014
  • 이 논문은 napthalimidopropylacrylate(NIPA)와 glycidylmethacrylate(GMA) 공중합체의 합성과 물성에 관한 연구로서 공중합체의 조성, 단량체 반응성비, 공명효과(Q)와 극성효과(e), 나프탈렌발색단을 가진 물질의 형광특성 등을 조사하였다. Azobisisobutyronitronitryl(AIBN) 개시제와 dimethylformamide(DMF) 용매를 $60^{\circ}C$에서 공중합하였다. 단량체의 반응성비는 Fineman-Ross(F-R), Kelen-$T{\ddot{u}}d{\ddot{o}}s$(K-T) 법으로 단량체 반응성비를 구한바, $r_1$$r_2$보다 크게 나타났다. NIPA이 GMA보다 공중합의 형성이 더 많음을 알 수 있다. 단량체 반응성비의 곱($r_1{\cdot}r_2$)이 1보다 적어서 불규칙한 교대공중합체가 형성되었고 다른 단량체끼리 결합하게 된 교호공중합체를 형성된 것으로 간주된다. 380 nm에서 약한 분자 형광띠와 460 nm에서 강한 중합체 엑시머 형광띠가 나타났다. NIPA 단량체의 형광수명은 실온에서 UV 355 nm 파장에서 형광붕괴커브를 나타냈으며 $5.1449{\times}10^{-7}s$로 나타났다. GMA 공단량체를 아크릴계에 공중합시켜 우수한 내열성 열경화성 접착제나 코팅제에 응용될 것으로 사료된다.

Karyotype Analyses of a Rice Cultivar 'Nakdong' and its Four Genetically Modified Events by Conventional Staining and Fluorescence in situ Hybridization

  • Jeon, Eun Jin;Ryu, Kwang Bok;Kim, Hyun Hee
    • 한국육종학회지
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    • 제43권4호
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    • pp.252-259
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    • 2011
  • Conventional staining and fluorescence in situ hybridization (FISH) karyotypes of the non-genetically modified (GM) parental rice line, 'Nakdong' (Oryza sativa L. japonica), and its four GM rice lines, LS28 (event LS30-32-20-1), Cry1Ac1 (event C7-1-9-1), and LS28 ${\times}$ Cry1Ac1 (events L/C1-1-3-1 and L/C1-3-1-1) were analyzed using 5S and 45S rDNAs as probes. Both parental and transgenic lines were diploids (2n=24) with one satellite chromosome pair. The lengths of the prometaphase chromosomes ranged from 1.50 to $6.30{\mu}m$. Four submetacentric and eight metacentric pairs comprised the karyotype of 'Nakdong' and its four GM lines. One pair of 5S rDNA signals was detected near the centromeric region of chromosome g in both the parental and transgenic lines. The 45S rDNA signals were detected on the secondary constrictions of the satellite chromosome pair in both the parental and transgenic lines. There was no significant difference in chromosome size, length, and composition between 'Nakdong' and its four GM lines. This research was conducted as a preliminary study for chromosomal detection of transgenes in GM rice lines and would be useful for their breeding programs.

Novel Effects of Polyelectrolytes on Fluorescence Quenching of Tris(2,2$^\prime$-bipyridine)ruthenium(Ⅱ) by Methyl Viologen and Cu$^{2+}$

  • Park, Joon-Woo;Paik, Young-Hee
    • Bulletin of the Korean Chemical Society
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    • 제6권5호
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    • pp.287-291
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    • 1985
  • The addition of poly(styrenesulfonate) (PSS) to $Ru(bpy)_3^{2+}$ solutions shifted the emission peak by 3 nm to red, and increased emission intensity by 1.8 times. By contrast, poly(vinylsulfonate) (PVS) had little effect on the fluorescence spectrum. The effects of PSS on the spectral properties of $Ru(bpy)_3^{2+}$, were attributed to the presence of a hydrophobic phenyl group in PSS, which interact with $Ru(bpy)_3^{2+}$ by, at least in part, hydrophobic effect. The binding constant of $Ru(bpy)_3^{2+}$ to PSS in 0.1 M NaCl was $6{\times}10^4\;M^{-1}$, and this value was about $10^3$ times higher than those of methyl viologen ($MV^{2+}$) and $Cu^{2+}$. The Stern-Volmer constants of emission quenching of $Ru(bpy)_3^{2+}$ by $MV^{2+}$ and $Cu^{2+}$ in 0.1 M NaCl solutions were 426 and 40 $M^{-1}$, which correspond to second order rate constants($k_q$) of $1.1{\times}10^9\;and\; 1.0{\times}10^8\;M^{-1}s^{-1}$, respectively. The presence of PSS enhanced $K_{SV's}\;by\;{\sim}50$ times, whereas PVS increased the values only 1-4 times. The large enhancing effect of PSS, despite of lower charge density than PVS, was explained in terms of longer life-time of photoexcited $Ru(bpy)_3^{2+}$ bound to PSS and strong association of $Ru(bpy)_3^{2+}$ to PSS due to a specific interaction involving hydrophobic effect. The variation of $K_{SV's}$ on the concentrations of PVS and PSS were also investigated for $Ru(bpy)_3^{2+}-MV^{2+}\;and \;Ru(bpy)_3^{2+}-Cu^{2+}$ photoredox systems.

Highly Fluorescing Solid DNA-Cationic Polyelectrolyte Complexes Prepared from a Natural DNA and a Poly(fluorenevinylene-alt-phenylene) Bearing Quaternary Ammonium Pendants

  • Yu, Young-Jun;Kwon, Young-Wan;Kim, Kyu-Nam;Do, Eui-Doo;Choi, Dong-Hoon;Jin, Jung-Il;Shin, Hee-Won;Kim, Yong-Rok;Kang, Ik-Joong;Mikroyannidis, John A.
    • Macromolecular Research
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    • 제17권4호
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    • pp.245-249
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    • 2009
  • A fluorescing, copolymer(Q)-bearing, quaternary ammonium pendant was mixed with excess natural salmon sperm DNA with a molecular weight of $1.3{\times}10^6$(2,000 base pairs) to afford highly fluorescing, complex mixtures. The fluorescence life-time of the polymer Q was greatly increased when mixed with DNA: for the mixture of Q:DNA=1:750 the fast and slow decay lifetimes increased from ca. 10 to 100 ps and from 20 ps to ca. 1 ns, respectively. The enhanced fluorescence of the mixtures was ascribed to efficient compartmentalization and reduced conformational relaxation of the polymer Q by complexation with excess DNA.

낙동강에서의 세균군집구조의 역동성 (Dynamics of in situ Bacterial Community Structure in the Nak-Dong River)

  • 박지은;여상민;이영옥
    • 생태와환경
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    • 제37권4호통권109호
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    • pp.363-367
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    • 2004
  • 낙동강 전 수계 8개 정점에서 분자기법인 FISH (Fluorescent in situ Hybridization)법으로 세균군집구조를 비교분석하였다. Eubacteria에 ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}-subclasses$ proteobacter CF group 세균의 합이 총세군수에서 차지하는 비율이 9.3-42.5%에서 변화하였고 그 최고치는 히상류, 청량에서 나타났다. 각 세균그룹이 총세균수에서 차지하는 비율이 10% 미만이었으나 최상류에서의 CF그룹이 총세균수에서 차지하는 비율은 23%이었다. 또한 유기물질을 분해해서 빠른 성장을 한다는 ${\gamma}-subclasses$ proteobacteria 세균군이 예상과는 달리 유기오염정도가 높은 하류에 비해 상류에서 더 많이 검출되었다. 아울러 암모니아산화세균은 $2.7-18.0{\times}10^4$ cells $mL^{-1}$의 범위에서 변화하였고 하류에서 최저치를 그리고 최고치는 중류에서 보였다. 반면에 아질산산화세균의 경우, 전수계에 걸쳐 정점간의 별 차이 없이 $5.2-7.7{\times}10^4$ Cells $mL^{-1}$에서 변화하였으며 그들이 총세균수에서 차지하는 비율은 두세균군간의 차이없이 1.0-13.6%에서 변화하였다. 결론적으로 FISH법은 통상적으로 세균군집의 정량적인 분석에 사용되지만 그 결과는 본 연구결과에서 보는 바와 같이 수계 환경의 현황에 관한 좋은 정보를 제공해주기도 한다.

치환된 나프탈이미드기를 가지는 비닐고분자의 합성과 형광특성(I) (Synthesis and Fluorescence Behavior of Vinyl Polymers with Substituted Naphthalimide Group(I))

  • 오대희
    • 한국인쇄학회지
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    • 제15권2호
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    • pp.77-90
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    • 1997
  • Positive type presensitized offset plate developer were blended by quantitative analysis method. The test had been proceeeded to check variation of developability, shelf life and tone reproduction by SiO2/Na2O ratio to PS plate developer, added glycerin, and sodium phosphate with glycerin. This study of tone reproduction had been tested 5 times to get accuracy by PS platesusing kodak CCG C-3, KMS. The test result of tone reproduction of presensitized offset plates can be summarized as follows ; major compositions in positive type plate developer were Na, Si, K and P, developability were increased by Sio2/NaO2 ratio in positive type plate developer. Shelf life can be kept by add glycerin to positive type plate developer. Tone reproduction were improved by sodium phosphate due to buffer action while shelf life can be kept by add glycerin in positive type plate developer.

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Effects of strong shading on growth and yield in sweet potato (Ipomoea batatas L. LAMK.)

  • Shin, Jong Moo;Song, Seon Hwa;Park, Chan Young;Lee, Hyeon Young;Shim, Sang In
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.241-241
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    • 2017
  • Sweet potatoes (Ipomoea batatas (L.) LAMK.,) have been cultivated in Central and South America for about 2000 years and are now grown mainly in Asia and South America. Sweet potatoes are annual in the temperate region, but are classified as perennial in the tropical region. In 2000, the cultivation area of sweet potatoes decreased to about 16,000 ha in 2000, but the cultivation area increased slightly in recent 20,000 ha in Korea. Sweet potatoes do not show higher maximum dry matter production of 120 ~ 150g per plant, and the leaf area index (LAI), which maximizes dry matter production, is known as 3.0 ~ 4.0. As the leaf area increase, the penetration of light into the canopy becomes poor, and sufficient photosynthesis cannot be achieved in the lower leaves, on the other hand the respiration increase, which results in poor dry matter production. This study was conducted to know the responses of sweet potatoes to intensive shading treatment of 80% shading. This experiment was conducted for about 42 days from September 6, 2016 to October 18, 2016 at Gyeongsang National University Experimental Farm, Jinju, Korea. The plant canopy was shaded with black nylon 80% shade cloth suspended 1.2 m above the ground. The photosynthetic rate, stomatal conductance, chlorophyll fluorescence, SPAD and NDVI were measured in 3 replicates every 7 days after shading initiation. After the fresh weight was measured, the samples were dried at $80^{\circ}C$ in a dry oven and measured. By the 80% shading treatment, chlorophyll fluorescence of the treated plants was slightly higher than that of the control, the SPAD value was higher by 3.4 and NDVI value was higher by 0.01. However, photosynthetic rate and stomatal conductance were lower than those of the control. The stomatal conductance of the control were two times higher than those of the control and the photosynthetic rate of the control was four times higher than that of the control. In control, plant showed a tendency to steadily increase in fresh weight and dry weight. However, in the case of shading treatment, the tendency to increase in the fresh and dry weight of tuberous roots was not clear. The fresh weight of shoot showed a tendency to increase steadily while the difference between treatment and control was not large, but tended to decrease after frost.

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The interaction of serum albumin with ginsenoside Rh2 resulted in the downregulation of ginsenoside Rh2 cytotoxicity

  • Lin, Yingjia;Li, Yang;Song, Zhi-Guang;Zhu, Hongyan;Jin, Ying-Hua
    • Journal of Ginseng Research
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    • 제41권3호
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    • pp.330-338
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    • 2017
  • Background: Ginsenoside Rh2 (G-Rh2) is a ginseng saponin that is widely investigated because of its remarkable antitumor activity. However, the molecular mechanism by which (20S) G-Rh2 triggers its functions and how target animals avoid its cytotoxic action remains largely unknown. Methods: Phage display was used to screen the human targets of (20S) G-Rh2. Fluorescence spectroscopy and UV-visible absorption spectroscopy were used to confirm the interaction of candidate target proteins and (20S) G-Rh2. Molecular docking was utilized to calculate the estimated free energy of binding and to structurally visualize their interactions. MTT assay and immunoblotting were used to assess whether human serum albumin (HSA), bovine serum albumin (BSA), and bovine serum can reduce the cytotoxic activity of (20S) G-Rh2 in HepG2 cells. Results: In phage display, (20S) G-Rh2-beads and (20R) G-Rh2-beads were combined with numerous kinds of phages, and a total of 111 different human complementary DNAs (cDNA) were identified, including HSA which had the highest rate. The binding constant and number of binding site in the interaction between (20S)-Rh2 and HSA were $3.5{\times}10^5M^{-1}$ and 1, and those in the interaction between (20S) G-Rh2 and BSA were $1.4{\times}10^5M^{-1}$ and 1. The quenching mechanism is static quenching. HSA, BSA and bovine serum significantly reduced the proapoptotic effect of (20S) G-Rh2. Conclusion: HSA and BSA interact with (20S) G-Rh2. Serum inhibited the activity of (20S) G-Rh2 mainly due to the interaction between (20S) G-Rh2 and serum albumin (SA). This study proposes that HSA may enhance (20S) G-Rh2 water solubility, and thus might be used as nanoparticles in the (20S) G-Rh2 delivery process.