• Title/Summary/Keyword: Fluorescence polarization

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Effects of Godulbaegi Extracts on the Stability and Fluidity of Phospholipid Liposomal Membranes (고들빼기 추출물이 인지질막 Liposome의 안정성 및 유동성에 미치는 영향)

  • 배송자;노승배;정복미
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.3
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    • pp.508-517
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    • 1998
  • We investigated the effects of godulbaegi extracts on the physiochemical properties of biological membranes as membrane stability and fluidity employing the phospholipid liposomal membrances as a biomembrane-mimetic system. The addition of the godulbaegi extracts to the phospholipid exterted great effects stagbilized the barrier function of the liposomal membranes in proportion to the concentration of the additive and significantly increased the membranes fluidity. The values of the fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH) decreased gradually as the temperature increased, and decreased abruptly near the phase transition temperature (Tm) of the liposome from gel to liquid crystalline state as usual. These results suggest that the activities of the godulbaegi extracts to enhance the stability and fluidity of the liposomal membranes have implication in their biological activities.

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Complex Detection Between Transcription Regulator and Promoter DNA by UV Spectroscopic Method

  • Lee, Kyungmin;Gang, Jongback
    • Journal of Integrative Natural Science
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    • v.5 no.3
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    • pp.163-167
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    • 2012
  • UV spectrophotometer was used to detect protein-DNA complex from DNA melting profile under constant temperature increase. Melting temperature (Tm) was $43^{\circ}C$ in copA duplex DNA alone. In the presence of Proteus mirabilis transcription regulator protein (PMTR) protein at 0.2 and 0.4 ${\mu}M$, Tm's were $45{\pm}0.5$ and $47.6{\pm}0.6^{\circ}C$, respectively. According to fluorescence polarization and gel shift assay. PMTR:copA complex was detected by the retarded migration on gel and the dissociation constant ($K_d$) was $(9.2{\pm}2.8){\times}10^{-9}M$.

Effects of Chlorhexidine Digluconate on Rotational Rate of n-(9-Anthroyloxy)stearic Acid in Porphyromonas ginginvalis Outer Membranes

  • Jang, Hye-Ock;Cha, Seong-Kweon;Lee, Chang;Choi, Min-Gak;Huh, Sung-Ryul;Shin, Sang-Hun;Chung, In-Kyo;Yun, Il
    • The Korean Journal of Physiology and Pharmacology
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    • v.7 no.3
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    • pp.125-130
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    • 2003
  • The aim of this study was to provide a basis for studying the molecular mechanism of pharmacological action of chlorhexidine digluconate. Fluorescence polarization of n-(9-anthroyloxy)stearic acid was used to examine the effect of chlorhexidine digluconate on differential rotational mobility of different positions of the number of membrane bilayer phospholipid carbon atoms. The six membrane components differed with respect to 2, 3, 6, 9, 12, and 16-(9-anthroyloxy)stearic acid (2-AS, 3-AS, 6-AS, 9-AS, 12-AS and 16-AP) probes, indicating different membrane fluidity. Chlorhexidine digluconate increased the rate of rotational mobility of hydrocarbon interior of the cultured Porphyromonas gingivalis outer membranes (OPG) in a dose-dependent manner, but decreased the mobility of surface region (membrane interface) of the OPG. Disordering or ordering effects of chlorhexidine digluconate on membrane lipids may be responsible for some, but not all of its bacteriostatic and bactericidal actions.

The Effect of Ethanol on the Physical Properties of Neuronal Membranes

  • Bae, Moon-Kyoung;Jeong, Dong-Keun;Park, No-Soo;Lee, Cheol-Ho;Cho, Bong-Hye;Jang, Hye-Ock;Yun, Il
    • Molecules and Cells
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    • v.19 no.3
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    • pp.356-364
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    • 2005
  • Intramolecular excimer formation of 1,3-di(1-pyrenyl) propane(Py-3-Py) and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to evaluate the effect of ethanol on the rate and range of lateral and rotational mobilities of bulk bilayer structures of synaptosomal plasma membrane vesicles (SPMVs) from the bovine cerebral cortex. Ethanol increased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py in the SPMVs. Selective quenching of both DPH and Py-3-Py by trinitrophenyl groups was used to examine the range of transbilayer asymmetric rotational mobility and the rate and range of transbilayer asymmetric lateral mobility of SPMVs. Ethanol increased the rotational and lateral mobility of the outer monolayer more than of the inner one. Thus ethanol has a selective fluidizing effect within the transbilayer domains of the SPMVs. Radiationless energy transfer from the tryptophans of membrane proteins to Py-3-Py was used to examine both the effect of ethanol on annular lipid fluidity and protein distribution in the SPMVs. Ethanol increased annular lipid fluidity and also caused membrane proteins to cluster. These effects on neuronal membranes may be responsible for some, though not all, of the general anesthetic actions of ethanol.

Differential Effects of Local Anesthetics on Rate of Rotational Mobility between Hydrocarbon Interior and Surface Region of Model Membrane Outer Monolayer

  • Chung, In-Kyo;Cha, Seong-Kweon;Chung, Yong-Za;Kim, Bong-Sun;Choi, Chang-Hwa;Cho, Goon-Jae;Jang, Hye-Ock;Yun, Il
    • The Korean Journal of Physiology and Pharmacology
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    • v.4 no.1
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    • pp.41-46
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    • 2000
  • Using fluorescence polarization of 12-(9-anthroyloxy)stearic acid (12-AS) and 2-(9-anthroyloxy)stearic acid (2-AS), we evaluated the differential effects of local anesthetics on differential rotational rate between the surface (in carbon number 2 and its surroundings including the head group) and the hydrocarbon interior (in carbon number 12 and its surroundings) of the outer monolayer of the total lipid fraction liposome extracted from synaptosomal plasma membrane vesicles. The anisotropy (r) values for the hydrocarbon interior and the surface region of the liposome outer monolayer were $0.078{\pm}0.001$ and $0.114{\pm}0.001,$ respectively. This means that the rate of rotational mobility in the hydrocarbon interior is faster than that of the surface region. In a dose-dependent manner, the local anesthetics decreased the anisotropy of 12-AS in the hydrocarbon interior of the liposome outer monolayer but increased the anisotropy of 2-AS in the surface region of the monolayer. These results indicate that local anesthetics have significant disordering effects on the hydrocarbon interior but have significant ordering effects on the surface region of the liposome outer monolayer.

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Luminescence Studies of N-Methyllutidone, an Unusually High Triplet Energy Sensitizer (N-메틸루티돈의 루미네센스에 관한 연구)

  • Sang Chul Shim;Myung Ho Hyun;Kuy Ho Chae
    • Journal of the Korean Chemical Society
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    • v.22 no.1
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    • pp.45-51
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    • 1978
  • The luminescence of N-methyllutidone is studied in ethanol matrix at $77^{\circ}C$K. No fluorescence is observed but a strong phosphorescence with the quantum yield of 0.1 and the lifetime of 0.2 sec is recorded. An unusually high triplet energy of 85.1 kcal/mole is determined for the compound from the O-O band of phosphorescence. The cis ${\leftrightarrow}$ trans photoisomerization of high triplet energy olefins such as 2-hexene and trans-1,4-dichlorobutene-2 is efficiently sensitized by N-methyllutidone substantiating the high triplet energy of the compound. The negative polarization of O-O band reveals the emitting triplet state to be $({\pi},{\pi}^*)^3$ state. Alkaline metal salts such as lithium chloride enhances the phosphorescence intensity through cation-N-methyllutidone coordination widening the gap between $({\pi},{\pi}^*)^3$and $(n,{\pi}^*)^3$ states.

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Conformational Change of Escherichia coli Signal Recognition Particle Ffh Is Affected by the Functionality of Signal Peptides of Ribose-Binding Protein

  • Ahn, Taeho;Ko, Ju Hee;Cho, Eun Yi;Yun, Chul-Ho
    • Molecules and Cells
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    • v.27 no.6
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    • pp.681-687
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    • 2009
  • We examined the effects of synthetic signal peptides, wild-type (WT) and export-defective mutant (MT) of ribose-binding protein, on the conformational changes of signal recognition particle 54 homologue (Ffh) in Escherichia coli. Upon interaction of Ffh with WT peptide, the intrinsic Tyr fluorescence, the transition temperature of thermal unfolding, and the GTPase activity of Ffh decreased in a peptide concentration-dependent manner, while the emission intensity of 8-anilinonaphthalene-1-sulfonic acid increased. In contrast, the secondary structure of the protein was not affected. Additionally, polarization of fluorescein-labeled WT increased upon association with Ffh. These results suggest that WT peptide induces the unfolded states of Ffh. The WT-mediated conformational change of Ffh was also revealed to be important in the interaction between SecA and Ffh. However, MT had marginal effect on these conformational changes suggesting that the in vivo functionality of signal peptide is important in the interaction with Ffh and concomitant structural change of the protein.

The Effect of Cephalosporins on the Stability of Gentamicin and Tobramycin in Human Serum (세파로스포린계 약물이 겐타마이신, 토브라마이신의 혈청중 안정성에 미치는 영향)

  • Kim, In Wha;Lee, Suk Hyang;Shin, Hyun Taek;Kim, Myung Min;Choi, Kyung Eob
    • Korean Journal of Clinical Pharmacy
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    • v.6 no.2
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    • pp.28-31
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    • 1996
  • The in vitro inactivation of gentamicin and tobramycin by four cephalosporins (cefotetan, cefuroxime, cefodizime, cefotiam) in human serum was investigated. Each cephalosporin was added to human serum samples containing gentamicin sulfate or tobramycin sulfate. Blank samples containing only aminoglycosides were used as controls. Samples were stored at -20, 4 and $25^{\circ}C$ and were analyzed for aminoglycoside concentrations by fluorescence polarization immunoassay ($TDxFLx^{TM}$ system) at 0, 2, 4, 8, 12, 24, 48 and 72 hours after mixing. The serum containing cefotiam stored at $25^{\circ}C$ showed significant inactivation of gentamicin by $12\%$ at 72 hours. The results indicate that cefotitan, cefuroxime and cefodizime do not inactivate gentamicin and tobramycin while cefotiam inactivates gentamicin.

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The Influence of Assay Error Weight on Gentamicin Pharmacokinetics Using the Bayesian and Nonlinear Least Square Regression Analysis in Appendicitis Patients

  • Jin, Pil-Burm
    • Archives of Pharmacal Research
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    • v.28 no.5
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    • pp.598-603
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    • 2005
  • The purpose of this study was to determine the influence of weight with gentamicin assay error on the Bayesian and nonlinear least squares regression analysis in 12 Korean appen dicitis patients. Gentamicin was administered intravenously over 0.5 h every 8 h. Three specimens were collected at 48 h after the first dose from all patients at the following times, just before regularly scheduled infusion, at 0.5 h and 2 h after the end of 0.5 h infusion. Serum gentamicin levels were analyzed by fluorescence polarization immunoassay technique with TDxFLx. The standard deviation (SD) of the assay over its working range had been determined at the serum gentamicin concentrations of 0, 2, 4, 8, 12, and 16 ${\mu}g$/mL in quadruplicate. The polynominal equation of gentamicin assay error was found to be SD (${\mu}g$/mL) = 0.0246-(0.0495C)+ (0.00203C$^2$). There were differences in the influence of weight with gentamicin assay error on pharmacokinetic parameters of gentamicin using the nonlinear least squares regression analysis but there were no differences on the Bayesian analysis. This polynominal equation can be used to improve the precision of fitting of pharmacokinetic models to optimize the process of model simulation both for population and for individualized pharmacokinetic models. The result would be improved dosage regimens and better, safer care of patients receiving gentamicin.

Assay Error for Improved Pharmacokinetic Modeling and Simulation of Vancomycin (반코마이신의 약물동태학적 모델링과 시뮬레이션의 향상을 위한 분석오차)

  • Burm, Jin Pil
    • YAKHAK HOEJI
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    • v.57 no.1
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    • pp.32-36
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    • 2013
  • The purpose of this study was to determine the influence of assay error for improved pharmacokinetic modeling and simulation of vancomycin on the Bayesian and nonlinear least squares regression analysis in 24 Korean gastric cancer patients. Vancomycin 1.0 g was administered intravenously over 1 hr every 12 hr. Three specimens were collected at 72 hr after the first dose from all patients at the following times, at 0.5 hr before regularly scheduled infusion, at 0.5 hr and 2 hr after the end of 1 hr infusion. Serum vancomycin levels were analyzed by fluorescence polarization immunoassay technique with TDX-FLX. The standard deviation (SD) of the assay over its working range had been determined at the serum vancomycin concentrations of 0, 20, 40, 60, 80 and $120{\mu}g/ml$ in quadruplicate. The polynomial equation of vancomycin assay error was found to be SD $({\mu}g/ml)=0.0224+0.0540C+0.00173C^2$ ($R^2=0.935$). There were differences in the influence of weight with vancomycin assay error on pharmacokinetic parameters of vancomycin using the nonlinear least squares regression analysis but there were no differences on the Bayesian analysis. This polynomial equation can be used to improve the precision of fitting of pharmacokinetic models to optimize the process of model simulation both for population and for individualized pharmacokinetic models. The result suggests the improvement of dosage regimens for the better and safer care of patients receiving vancomycin.