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Analytical Sciences : the International... 2010A simple and homogeneous method based on aptamer and pyrene moieties for the detection of K(+) was developed. The aptamer was labeled by pyrene moiety at 3' end as the...
A simple and homogeneous method based on aptamer and pyrene moieties for the detection of K(+) was developed. The aptamer was labeled by pyrene moiety at 3' end as the molecular recognition element. In the presence of K(+), the complementary oligonucleotide labeled by pyrene moiety at 5' end was displaced from the aptamer, which was accompanied by a dramatic decrease of the excimer fluorescence of pyrene. However, the excimer fluorescence remains in the absence of the target. With optimum conditions, relative changes of the pyrene excimer fluorescence intensity were proportional to the concentrations of K(+) in the range of 6.3 × 10(-4) to 1.0 × 10(-2) M with a detection limit of 5.0 × 10(-4) M. Importantly, in the presence of Na(+), NH(4)(+), Mg(2+) and Ca(2+) cations of biological fluids, this method was able to detect K(+) with high selectivity. In a word, the assay seems to have great potential applications, especially in biological fluids due to its simplicity, specificity and homogeneous detection.
Topics: Animals; Aptamers, Nucleotide; Biosensing Techniques; Body Fluids; Cations; Fluorescence; Humans; Limit of Detection; Methods; Potassium; Pyrenes; Sensitivity and Specificity
PubMed: 21157094
DOI: 10.2116/analsci.26.1261 -
Biophysical Journal Jul 1991The dynamics of fluorescence quenching and the organization of a series of pyrene derivatives anchored in various depths in bilayers of phosphatidylcholine small...
The dynamics of fluorescence quenching and the organization of a series of pyrene derivatives anchored in various depths in bilayers of phosphatidylcholine small unilamellar vesicles was studied and compared with their behavior in homogeneous solvent systems. The studies include characterization of the environmental polarity of the pyrene fluorophore based on its vibronic peaks, as well as the interaction with three collisional quenchers: the two membrane-soluble quenchers, diethylaniline and bromobenzene, and the water soluble quencher potassium iodide. The system of diethylaniline-pyrene derivatives in the membrane of phosphatidylcholine vesicles was characterized in detail. The diethylaniline partition coefficient between the lipid bilayers and the buffer is approximately 5,800. Up to a diethylaniline/phospholipid mole ratio of 1:3 the perturbation to membrane structure is minimal so that all photophysical studies were performed below this mole ratio. The quenching reaction, in all cases, was shown to take place in the lipid bilayer interior and the relative quenching efficiencies of the various probe molecules was used to provide information on the distribution of both fluorescent probes and quencher molecules in the lipid bilayer. The quenching efficiency by diethylaniline in the lipid bilayer was found to be essentially independent on the length of the methylene chain of the pyrene moiety. These findings suggest that the quenching process, being a diffusion controlled reaction, is determined by the mobility of the diethylaniline quencher (with an effective diffusion coefficient D approximately 10(-7) cm2 s-1) which appears to be homogeneously distributed throughout the lipid bilayer. The pulsed laser photolysis products of the charge-transfer quenching reaction were examined. No exciplex (excited-complex) formation was observed and the yield of the separated radical ions was shown to be tenfold smaller than in homogenous polar solutions. The decay of the radical ions is considerably faster than the corresponding process in homogenous solutions. Relatively high intersystem crossing yields are observed. The results are explained on the basis of the intrinsic properties of a lipid bilayer, primarily, its rigid spatial organization. It is suggested that such properties favor ion-pair formation over exciplex generation. They also enhance primary geminate recombination of initially formed (solvent-shared) ion pairs. Triplet states are generated via secondary geminate recombination of ion pairs in the membrane interior. The results bear on the general mechanism of electron transfer processes in biomembranes.
Topics: Calorimetry, Differential Scanning; Kinetics; Lipid Bilayers; Magnetic Resonance Spectroscopy; Mathematics; Models, Theoretical; Molecular Structure; Phosphatidylcholines; Phosphorus; Pyrenes; Spectrometry, Fluorescence; Structure-Activity Relationship
PubMed: 1883931
DOI: 10.1016/S0006-3495(91)82035-5 -
Applied and Environmental Microbiology May 2000Pyrene is a regulated pollutant at sites contaminated with polycyclic aromatic hydrocarbons (PAH). It is mineralized by some bacteria but is also transformed to...
Pyrene is a regulated pollutant at sites contaminated with polycyclic aromatic hydrocarbons (PAH). It is mineralized by some bacteria but is also transformed to nonmineral products by a variety of other PAH-degrading bacteria. We examined the formation of such products by four bacterial strains and identified and further characterized the most apparently significant of these metabolites. Pseudomonas stutzeri strain P16 and Bacillus cereus strain P21 transformed pyrene primarily to cis-4,5-dihydro-4,5-dihydroxypyrene (PYRdHD), the first intermediate in the known pathway for aerobic bacterial mineralization of pyrene. Sphingomonas yanoikuyae strain R1 transformed pyrene to PYRdHD and pyrene-4,5-dione (PYRQ). Both strain R1 and Pseudomonas saccharophila strain P15 transform PYRdHD to PYRQ nearly stoichiometrically, suggesting that PYRQ is formed by oxidation of PYRdHD to 4,5-dihydroxypyrene and subsequent autoxidation of this metabolite. A pyrene-mineralizing organism, Mycobacterium strain PYR-1, also transforms PYRdHD to PYRQ at high initial concentrations of PYRdHD. However, strain PYR-1 is able to use both PYRdHD and PYRQ as growth substrates. PYRdHD strongly inhibited phenanthrene degradation by strains P15 and R1 but had only a minor effect on strains P16 and P21. At their aqueous saturation concentrations, both PYRdHD and PYRQ severely inhibited benzo[a]pyrene mineralization by strains P15 and R1. Collectively, these findings suggest that products derived from pyrene transformation have the potential to accumulate in PAH-contaminated systems and that such products can significantly influence the removal of other PAH. However, these products may be susceptible to subsequent degradation by organisms able to metabolize pyrene more extensively if such organisms are present in the system.
Topics: Bacillus cereus; Biodegradation, Environmental; Biotransformation; Kinetics; Mycobacterium; Polycyclic Aromatic Hydrocarbons; Pseudomonas; Pyrenes; Sphingomonas
PubMed: 10788360
DOI: 10.1128/AEM.66.5.1917-1922.2000 -
Microbiological Research Dec 2021This research was focused on the isolation and characterization of a PAH-catabolizing mycobacterial strain from the petroleum hydrocarbon-contaminated rhizosphere of...
This research was focused on the isolation and characterization of a PAH-catabolizing mycobacterial strain from the petroleum hydrocarbon-contaminated rhizosphere of alfalfa, as well as on revealing some points of interaction between the microorganism and the plant. Mycolicibacterium sp. PAM1, a pyrene degrader isolated from the niche of interest to us, can catabolize fluoranthene, anthracene, fluorene, and phenanthrene. On the basis of curves of PAM1 growth with different PAHs as the sole carbon sources and on the basis of PAH-degradation rates, we found that pollutant availability to the strain decreased in the sequence phenanthrene > fluorene > fluoranthene ∼ pyrene > anthracene. For each PAH, the catabolic products were identified. PAM1 was found to have the functional genes nidA and nidB. New data modeling the 2D and 3D structures, intrinsic structural disorder, and molecular dynamics of the nidA and nidB gene products were obtained. The identified genes and intermediates of pyrene degradation indicate that PAM1 has a PAH catabolic pathway that is peculiar to known mycobacterial pyrene degraders. PAM1 utilized some components of alfalfa root exudates as nutrients and promoted plant growth. The use of mycobacterial partners of alfalfa is attractive for enhancing the phytoremediation of PAH-contaminated soils.
Topics: Anthracenes; Fluorenes; Host Microbial Interactions; Medicago sativa; Mycobacteriaceae; Phenanthrenes; Polycyclic Aromatic Hydrocarbons; Pyrenes; Rhizosphere
PubMed: 34624611
DOI: 10.1016/j.micres.2021.126885 -
The Journal of Biological Chemistry Feb 1996In lipid bilayers, pyrene and pyrene-labeled lipids form excimers in a concentration-dependent manner. The aromatic amine N, N-diethylaniline (DEA), which has a high... (Comparative Study)
Comparative Study
In lipid bilayers, pyrene and pyrene-labeled lipids form excimers in a concentration-dependent manner. The aromatic amine N, N-diethylaniline (DEA), which has a high membrane-to-medium partition coefficient, quenches the monomers only, and therefore it is expected that under conditions in which the monomers are in equilibrium with the excimers due to the mass law, the Stern-Volmer coefficient (Ksv) for monomers (M), defined as KM, should be identical to that of the excimer (E), defined as KE, and KE/KM = 1. 0. This is indeed the case for pyrene and pyrene valerate in egg phosphatidylcholine small unilamellar vesicles. However, for pyrene decanoate and pyrene dodecanoate in these vesicles, and for N-[12-(1-pyrenyl)dodecanoyl]sphingosylphosphocholine in a matrix of either N-stearoyl sphingosylphosphocholine or 1-palmitoyl-2-oleoyl phosphatidylcholine, KE < KM. This can be explained either by the existence of (a) two subpopulations of excimers, one in fast equilibrium with the monomers and the other, related to ground-state protoaggregates of pyrene lipids; (b) two monomer subpopulations where part of M cannot be quenched by DEA; or (c) two monomer subpopulations, both quenched by DEA, but only one of which produces excimers. The good agreement between the photophysical processes determined by steady state and time-resolved measurements supports the third explanation for the bilayers containing pyrene phospholipids. It also suggests that the main factors determining the immiscibility of pyrene lipids in phospholipid bilayers are the temperature, the difference in the gel-to-liquid-crystalline phase transition temperature (deltaTm) between the matrix and the pyrene lipid, and the structural differences between the matrix lipid and the pyrene-labeled lipid. These results indicate that the KE/KM ratio can serve as a very sensitive tool to quantify isothermal microscopic immiscibility in membranes. This novel approach has the following advantages: applicability to fluid phase immiscibility, requirement of a relatively low mol fraction of pyrene lipids, and conceivably, applicability to biological membranes.
Topics: Kinetics; Lipid Bilayers; Phosphatidylcholines; Pyrenes; Spectrometry, Fluorescence; Structure-Activity Relationship
PubMed: 8621705
DOI: 10.1074/jbc.271.6.3085 -
Molecules (Basel, Switzerland) Sep 2015Dendrimers bearing pyrene donor groups have been obtained and act as efficient light-harvesting antennae capable of transferring light energy through space from their...
Dendrimers bearing pyrene donor groups have been obtained and act as efficient light-harvesting antennae capable of transferring light energy through space from their periphery to their core. The light-harvesting ability increases with each generation due to an increase in the number of peripheral pyrenes. In order to evaluate the photovoltaic properties of the compounds, thermal evaporated thin films were produced and the voltage response in the presence of visible light was obtained. The energy transfer efficiency was found to be almost quantitative for the first and second generations. The dendrimers have the potential to become integral components of molecular photonic devices.
Topics: Dendrimers; Electrochemistry; Energy Transfer; Light-Harvesting Protein Complexes; Molecular Structure; Porphyrins; Pyrenes
PubMed: 26402663
DOI: 10.3390/molecules200917533 -
Synthesis and Configurational Character Study of Novel Structural Isomers Based on Pyrene-Imidazole.Molecules (Basel, Switzerland) Jun 2019Isomers provide more possibilities for the structure of organic compounds. Molecular structures determine their corresponding properties, therefore the intrinsic...
Isomers provide more possibilities for the structure of organic compounds. Molecular structures determine their corresponding properties, therefore the intrinsic relationship between structure and properties of isomers is of great research value. Isomers with a stable structure and excellent performance possess more potential for development and application. In this paper, we design and synthesize structural isomers with different molecular symmetries based on the asymmetric structure of imidazole and the symmetrical structure of pyrene. Isomers with stable molecular structures can be obtained by a simple and efficient "one-pot" reaction, involving axisymmetric configuration and centrosymmetric configuration. Using this "click-like" reaction, the structure of target molecules is controllable and adjustable. Furthermore, the effect of molecular configurations on molecular stacking of crystal is studied. The variation of the optical and thermal properties, the optimized structures, and orbital distributions of isomers depends on different molecular geometry with different symmetry, which are revealed by crystallographic analysis. This present strategy provides an efficient synthetic method for the design and synthesis of structural isomers based on pyrene-imidazole.
Topics: Crystallography; Imidazoles; Isomerism; Molecular Structure; Pyrenes
PubMed: 31226827
DOI: 10.3390/molecules24122293 -
PloS One 2017Our previous study on prion-infected rodents revealed that hydroxypropyl methylcellulose compounds (HPMCs) with different molecular weights but similar composition and...
Pyrene conjugation and spectroscopic analysis of hydroxypropyl methylcellulose compounds successfully demonstrated a local dielectric difference associated with in vivo anti-prion activity.
Our previous study on prion-infected rodents revealed that hydroxypropyl methylcellulose compounds (HPMCs) with different molecular weights but similar composition and degree of substitution have different levels of long-lasting anti-prion activity. In this study, we searched these HPMCs for a parameter specifically associated with in vivo anti-prion activity by analyzing in vitro chemical properties and in vivo tissue distributions. Infrared spectroscopic and thermal analyses revealed no differences among HPMCs, whereas pyrene conjugation and spectroscopic analysis revealed that the fluorescence intensity ratio of peak III/peak I correlated with anti-prion activity. This correlation was more clearly demonstrated in the anti-prion activity of the 1-year pre-infection treatment than that of the immediate post-infection treatment. In addition, the intensity ratio of peak III/peak I negatively correlated with the macrophage uptake level of HPMCs in our previous study. However, the in vivo distribution pattern was apparently not associated with anti-prion activity and was different in the representative tissues. These findings suggest that pyrene conjugation and spectroscopic analysis are powerful methods to successfully demonstrate local dielectric differences in HPMCs and provide a feasible parameter denoting the long-lasting anti-prion activity of HPMCs in vivo.
Topics: Animals; Biological Transport; Brain; Electric Impedance; Hypromellose Derivatives; Macrophages; Mice; Molecular Weight; Prion Proteins; Pyrenes; Spectroscopy, Fourier Transform Infrared; Spleen; Structure-Activity Relationship; Tissue Distribution
PubMed: 28934337
DOI: 10.1371/journal.pone.0185357 -
Journal of Nanobiotechnology Jan 2020During the past few decades, drug delivery system (DDS) has attracted many interests because it could enhance the therapeutic effects of drugs and reduce their side...
BACKGROUND
During the past few decades, drug delivery system (DDS) has attracted many interests because it could enhance the therapeutic effects of drugs and reduce their side effects. The advent of nanotechnology has promoted the development of nanosized DDSs, which could promote drug cellular uptake as well as prolong the half-life in blood circulation. Novel polymer micelles formed by self-assembly of amphiphilic polymers in aqueous solution have emerged as meaningful nanosystems for controlled drug release due to the reversible destabilization of hydrophobic domains under different conditions.
RESULTS
The amphiphilic polymers presented here were composed of cholesterol groups end capped and poly (poly (ethylene glycol) methyl ether methacrylate) (poly (OEGMA)) as tailed segments by the synthesis of cholesterol-based initiator, followed by atom transfer radical polymerization (ATRP) with OEGMA monomer. FT-IR and NMR confirmed the successfully synthesis of products including initiator and polymers as well as the Mw of the polymers were from 33,233 to 89,088 g/mol and their corresponding PDI were from 1.25 to 1.55 by GPC. The average diameter of assembled polymer micelles was in hundreds nanometers demonstrated by DLS, AFM and SEM. The behavior of the amphiphilic polymers as micelles was investigated using pyrene probing to explore their critical micelle concentration (CMC) ranging from 2.53 × 10 to 4.33 × 10 mg/ml, decided by the balance between cholesterol and poly (OEGMA). Besides, the CMC of amphiphilic polymers, the quercetin (QC) feeding ratio and polarity of solvents determined the QC loading ratio maximized reaching 29.2% certified by UV spectrum, together with the corresponding size and stability changes by DLS and Zeta potential, and thermodynamic changes by TGA and DSC. More significantly, cholesterol end-capped polymer micelles were used as nanosized systems for controlled drug release, not only alleviated the cytotoxicity of QC from 8.6 to 49.9% live cells and also achieved the QC release in control under different conditions, such as the presence of cyclodextrin (CD) and change of pH in aqueous solution.
CONCLUSIONS
The results observed in this study offered a strong foundation for the design of favorable polymer micelles as nanosized systems for controlled drug release, and the molecular weight adjustable amphiphilic polymer micelles held potential for use as controlled drug release system in practical application.
Topics: Animals; Cell Line; Cell Survival; Cholesterol; Cyclodextrins; Drug Carriers; Drug Liberation; Hydrophobic and Hydrophilic Interactions; Mice; Micelles; Myoblasts; Nanoparticles; Polyethylene Glycols; Pyrenes; Quercetin
PubMed: 31941501
DOI: 10.1186/s12951-020-0575-y -
International Journal of Environmental... Apr 2005Inorganic ions, coenzymes, amino acids, and saccharides could co-exist with toxic environmental chemicals, such as polycyclic aromatic hydrocarbons (PAHs), in the cell....
Inorganic ions, coenzymes, amino acids, and saccharides could co-exist with toxic environmental chemicals, such as polycyclic aromatic hydrocarbons (PAHs), in the cell. The presence of these co-existing chemicals can modulate the toxicity of the PAHs. One of the genotoxic effects by PAHs is light-induced cleavage, or photocleavage, of DNA. The effect of inorganic ions I-, Na+, Ca2+, Mg2+, Fe3+, Mn2+, Cu2+, and Zn2+ and biological molecules riboflavin, histidine, mannitol, nicotinamide adenine dinucleotide (NAD), glutathione, and glutamic acid on the DNA photocleavage by pyrene, 1-hydroxypyrene (1-HP), and 1-aminopyrene (1-AP), is studied. The non-transition metal ions Na+, Ca2+, and Mg2+, usually have very little inhibitory effects, while the transition metal ions Fe3+, Cu2+, and Zn2+ enhance, Mn2+ inhibits the DNA photocleavage. The effect by biological molecules is complex, depending on the photochemical reaction mechanisms of the compounds tested (1-AP, 1-HP and pyrene) and on the chemical nature of the added biological molecules. Riboflavin, histidine, and mannitol enhance DNA photocleavage by all three compounds, except that mannitol has no effect on the photocleavage of DNA by pyrene. Glutathione inhibits the DNA photocleavage by 1-AP and 1-HP, but has no effect on that by pyrene. NAD enhances the DNA photocleavage by 1-AP, but has no effect on that by 1-HP and pyrene. Glutamic acid enhances the DNA photocleavage by 1-AP and pyrene, but inhibits that by 1-HP. These results show that the co-existing chemicals may have a profound effect on the toxicity of PAHs, or possibly on the toxicity of many other chemicals. Therefore, if one studies the toxic effects of PAHs or other toxic chemicals, the effect of the co-existing chemicals or ions needs to be considered.
Topics: DNA Damage; DNA, Superhelical; Electrophoresis, Agar Gel; Glutamic Acid; Histidine; Iodine; Ions; Metals; Mutagenicity Tests; NAD; Photochemistry; Pyrenes; Riboflavin; Ultraviolet Rays
PubMed: 16705811
DOI: 10.3390/ijerph2005010132