共查询到20条相似文献,搜索用时 15 毫秒
1.
In the high-purity membranes of the prolamellar bodies (PLB) of etioplasts, the main protein component of which is protochlorophyllide oxidoreductase (POR), protein fluorescence in the 320–350-nm region with a maximum in the excitation spectrum at 278–280 nm has been revealed. The microsurrounding of protein fluorophors in an acidic medium (pH 4.0) is the most hydrophobic. Transfer of energy from the protein to pyrene present in the lipid of the PLB membranes is observed, but fluorescence of protochlorophyllide (Pd) is absent when pyrene is excited via protein. A change in the content of Pd and carotenoids in the membranes of PLB influences the degree of excimerization of the acceptor molecules of pyrene (inverse dependence). The character of interaction of POR with a membrane with allowance for the data on its primary and secondary structures is discussed. 相似文献
2.
G. E. Savchenko E. A. Klyuchareva I. I. Denev A. P. Stupak 《Journal of Applied Spectroscopy》2000,67(3):473-481
The fluorescence parameters of pyrene and pyrenedecanoic acid in lipid micelles and native membranes of etioplasts whose basic
lipid components are mono- and digalactosyldiacylglycerol (MGDG and DGDG) have been investigated. The vibrational structure
of the emission spectra of pyrene (λexc = 337 nm) in the 370–400-nm range points to the hydrophilic microsurrounding of pyrene molecules in all types of the investigated
membranes. The absence of MGDG from liposomes leads to a decrease in the degree of excimerization of a probe. In native membranes,
this parameter increases with increasing content of pigments. Pyrene covalently bound to decanoic acid is found in the membranes
of prolamellar bodies and in artificial monolayer micellae in an even more hydrophilic microsurrounding than the molecules
of a free probe, and a decrease in the degree of eximerization is observed thereby. The specific features of localization
of the investigated probes in plastid membranes are discussed.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 344–349, May–June, 2000. 相似文献
3.
Four novel pentamethine cyanines have been investigated for their photophysical behaviors and photochemical stability in Nafion-Na+ membranes. The incorporation processes of these dyes into Nafion membranes are diffusion-controlled and the apparent diffusion constants have been determined. Fluorescence quantum yields and fluorescence lifetimes of all tested dyes in Nafion membranes have been determined and significant fluorescence enhancements were observed with respect to their fluorescence in aqueous solution. Photolysis of these dyes suggested these dye molecules are stabilized significantly by Nafion membranes. Furthermore, the fluorescence enhancements and the photostabilization of these dyes are more significant in dry Nafion membranes than those in wet ones. 相似文献
4.
The dynamic properties of the lipid layer of intraplastid membranes have been studied by analyzing the stationary and kinetic spectral polarization characteristics of the fluorescence of lipophilic probes of pyrene and diphenylhexatriene (DPH). Based on the data of the decay of the fluorescence anisotropy of pyrene, the value of the microviscosity of lipids in the membranes of prolamellar bodies (PLB) and protilakoids of etioplasts has been calculated. The pyrene molecules built into the membranes of etioplasts have a relatively high rotational mobility (stationary anisotropy r
s < 0.1). The DPH molecules rotate with difficulty in etioplast membranes (r
s > 0.3). After photoreduction of protochlorophyllide (Pd) in vivo, the rotation of the pyrene and DPH molecules in the membranes of prolamellar bodies becomes easier and this leads to a decrease in r
s. Illumination raised the degree of excimerization of the pyrene immersed into lipids (exc = 337 nm), and the microsurrounding of the molecules of the probe in lipids became more hydropholic (the relationship between the vibronic maxima at 373 and 387 nm decrease). The set of data obtained points to a decrease in the microviscosity of the lipid layer of the membranes of prolamellar bodies as a result of illumination of sproutings. 相似文献
5.
6.
Kudrinskiy AA Krutyakov YA Olenin AY Romanovskaya GI Vasilyeva SY Lisichkin GV 《Journal of fluorescence》2009,19(3):473-478
The fluorescence of pyrene adsorbed onto the surface of the cetyltrimethylammonium-coated silver nanoparticles was studied.
Pyrene molecules adsorbed on freshly prepared silver particles were found to be in close proximity to silver surface thus
providing the possibility of energy transfer from excited pyrene to silver cores of the particles. In that case along with
the expected fluorescence of pyrene we observed the fluorescence of the silver nanoparticles induced by the excited pyrene
molecules. In due course the restructuring of the cetyltrimethylammonium layer resulted in moving of pyrene molecules away
from silver surface and simultaneous disappearance of the silver nanoparticles fluorescence band. These data strongly support
the recent hypothesis of fluorophore-plasmon coupled emission. 相似文献
7.
多环芳烃由于具有三致(致癌、致畸、致突变)特性,其在环境中的检测受到人们广泛关注。利用时间分辨光谱技术,研究了荧蒽乙醇溶液的荧光光谱随延时时间和门宽改变的特性。研究了不同浓度荧蒽的时间分辨荧光光谱特性,以原始浓度的荧蒽为初始溶液,通过逐级稀释的方式,最终将原始溶液稀释16倍,拟合了不同稀释倍数下的荧蒽荧光强度衰减随延时时间变化的动力学曲线,得到了不同浓度荧蒽的拟合荧光寿命。研究结果表明,荧蒽的荧光光谱特性与光谱仪探测器延时时间和门宽宽度密切相关。固定延时时间,随着光谱仪门宽宽度的变化,荧蒽的荧光强度随着门宽的增大而逐渐增强。固定门宽,改变延时时间的过程中,荧蒽的荧光强度随延时时间呈现先增大,后减小的趋势。荧蒽的荧光强度随延时时间的衰减过程符合指数衰减过程,将荧蒽乙醇溶液进行逐级稀释,荧蒽荧光强度与延时时间的衰减进行指数拟合后,得到不同稀释倍数的荧蒽乙醇溶液的衰减动力学参数,随着稀释倍数的增大,拟合得到的荧蒽荧光寿命增大。多环芳烃时间分辨光谱特征的研究,可以为环境中多环芳烃的检测提供技术基础,由于不同荧光物质具有特征的荧光寿命,因此,可以利用多环芳烃与环境中其他荧光物质的不同荧光寿命特性,准确识别环境中的多环芳烃污染物。 相似文献
8.
The redistribution between two excited forms of pyrene accompanying a change in the intramembrane probe concentration yields
a set of fluorescence spectra that intersect at a single common (isobestic) point. Infensities of monomer and excimer fluorescence
(Im and Ie, respectively) are related by a linear dependence: Ie+kIm=Is. The coefficient k depends on the membrane type and temperature. Fluorescence intensity at the isobestic point (Ii) along with the proportional quantity Is reflect the total steady-state level of excited pyrene forms and do not depend on the excimerization degree (Ie/Im ratio), and can be used when estimating the quenching degree of pyrene fluorescence in biological membranes.
Institute of Photobiology, Academy of Sciences of Belarus, 27, F. Skorina St., Minsk, 220072, Belarus. Translated from Zhurnal
Prikladnoi Spektroskopii, Vol. 64, No. 2, pp. 204–208, March–April, 1997. 相似文献
9.
10.
11.
Jacek Goc Alina Dudkowiak Zygmunt Gryczyński Ignacy Gryczyński Bogumil Zelent Danuta Frąckowiak 《Journal of fluorescence》2001,11(1):53-63
Polarized absorption and fluorescence spectra of bacteriochlorophyll c and green photosynthetic bacterium Prostheecochloris aestuarii cells and cell fragments embedded in stretched polymer film were measured. In pigment samples the artificial oligomers of bacteriochlorophyll c (with absorption about 750 nm) and other forms of this pigment and bacteriopheophytin (with absorption at 670 nm) were present. In bacteria samples, embedded in polymer, oligomers were in high degree disaggregated and as a result the absorption about 670 nm was observed. Previously for similar sets of samples the decay of fluorescence excited only at one wavelength was analyzed on three exponential components, but exact lifetime values of these components for various samples were different. The aim of present paper was to check if these differences occur because of various contributions to decay from three well defined forms or if they were related to the existence of several pigment forms with slightly different lifetimes. The global analysis of data obtained for various excitation and observation wavelengths of fluorescence were done. From this analysis it follows that the second situation occurs. For a model system containing artificial oligomers the largest component of decay has a 4 of about 0.183 ns or 0.136 ns depending on observation wavelength. For the bacteria sample, in which the emission at 680 nm is the superposition from various pigments, global analysis done for various excitation wavelengths shows also that the values differ depending on the regions of fluorescence observation. From polarized spectra, it follows that in the model system the pigments absorbing at 670 nm are randomly distributed whereas oligomers are highly oriented. In bacteria fragments absorbing at 670 nm pigment molecules can be divided into two groups: one oriented along the axis of film stretching and the second practically randomly distributed. In living organisms, under some conditions, small amount of 670 nm pigments can be present and can work as excitation energy traps or as antenna transferring the excitation. Present results show that the role of various pools of 670 nm absorbing pigments can be different because of their differing orientation. 相似文献
12.
P. Cavatorta R. Favilla A. Mazzini L. Franzoni A. Spisni A. G. Szabo 《Journal of fluorescence》1993,3(4):211-214
The conformation of the nonapeptide hormone litorin has been studied in buffer and in the presence of lipids, using static and dynamic fluorescence. The results obtained show that, in buffer, the hormone probably exists in a collection of flexible conformers, slowly interconverting between them. The marked changes observed in fluorescence spectra and lifetimes upon addition of dimyristoylphosphatidylserine vesicles clearly show that the peptide interacts with lipids assuming lipid specific conformations. Interestingly, no significative spectroscopic changes are produced by exposure to dimirystoylphosphatidylcholine vesicles both in the gel and liquid-christalline phases, suggesting a requirement for negatively charged lipids during the process of hormone-membrane interaction. 相似文献
13.
磷酸盐钕玻璃的荧光寿命和损耗对激光增益特性的影响 总被引:4,自引:3,他引:1
实验研究了目前使用的N2122和N3122掺钕磷酸盐玻璃中不同的OH基浓度对玻璃荧光寿命的影响,同时从实验和理论上研究了荧光寿命和损耗对激光增益特性的影响,结果表明,增加玻璃的荧光寿命是提高增益性能的一个重要方法,当玻璃的荧光寿命增加10%时小信号增益系数提高5%左右,提高钕玻璃的荧光寿命,可适当降低对损耗的要求,也能够保持它的增益性能不变。 相似文献
14.
The constants of binding dye molecules with the micelles of sodium dodecyl sulfate are determined using quenching of delayed fluorescence of acridine dyes by sodium iodide in aqueous–micellar solutions. Kinetic equations have been composed that describe the processes of deactivation of the excited states of dyes. By solving these equations at the concentration of the quencher sodium iodide corresponding to the minimum lifetime of triplet states and at the concentration of micelles corresponding to the least value of the delayed fluorescence quenching rate constants, we obtained the constants of binding dyes with micelles equal to 1.3·107, 2.9·107, and 3.1·107 M–1 for trypaflavine, acridine orange, and acridine yellow, respectively. We calculated the rate constants of quenching of the triplet states of the molecules of dyes by iodide ions (I
–) that decreased in transition from trypaflavine to acridine orange and acridine yellow. 相似文献
15.
Time-resolved fluorescence of eight fluorescence probes were studied in EggPC bilayer membrane vesicles. Emission wavelength dependent fluorescence decays were analyzed in a model-independent way to obtain time resolved area normalized emission spectra (TRANES). The TRANES spectra of the probes studied were classified into four types: (1) spectra that are identical at all time (one emissive species), (2) spectra that show an isoemissive point (two emissive species), (3) spectra that shift continuously with time (slow solvation dynamics or multiple species), and (4) spectra that shift for a short time and thereafter one or two emissive species are indicated. The TRANES spectra of these eight probes, except RH421, belong to the type 1, 2, or 4. The continuous shift of the TRANES spectra that was observed for the probe RH421 is attributed to multiple ground state species and not due to slow solvation dynamics. 相似文献
16.
Three new mesoionic oxazolo[3,2-b]pyridazin-2-one derivatives, in different solutions have been investigated by UV-Vis absorption, steady-state and time-resolved fluorescence methods. The effect of substituents on the extension of conjugation of the pi-electrons from mesoionic oxazolone has been evidenced by bathochromic shifts of the absorption and fluorescence maxima positions. The fluorescence decay data could be fitted to single-exponential or double-exponential function. The lifetime values are much higher in aprotic polar solvents and in the case of the derivatives that present an extension of the conjugation of pi-electrons. The properties of the compounds present a solvent dependence, being tested in micellar solutions as potential molecular probe "sensitive" to the environment polarity. 相似文献
17.
研究了小波图象边缘检测技术在荧光寿命显微像分析中的应用,利用小波分析的多尺度特性进行了荧光寿命显微像的边缘提取,结果表明,这种方法非常有效。 相似文献
18.
Jie Zheng 《Journal of Macromolecular Science: Physics》2014,53(11):1739-1749
A series of nonionic polyurethanes were dissolved in water and their miceller self-assembly behaviors were characterized by aid of a fluorescence spectrophotometer. Fluorescence and resonance light scattering techniques were carried out for characterizing the micelles, and information such as aggregation number, critical micelle concentration, micropolarity, and micelle volume change was obtained. The micropolarity decreased as the aggregation number increased. The nonionic polyurethane micelle volume with two long ethoxyl chains per polyurethane molecule was smaller than the one with short chains, even with the same aggregation number, and was less polar. The micropolarity depended on both the aggregation number and the volume of a single micelle. 相似文献
19.
20.
The analysis of time-resolved fluorescence of monopyrenyl phospholipid monomer and excimer emission is reviewed using a model based on the diffusion equation for bimolecular reactions in two-dimensional planar membrane bilayers. This aspect is illustrated by the analysis of a real experiment. The method can also be extended to short-range diffusion, which can be measured for dipyrenyl phospholipids in membrane bilayers. The latter aspect is illustrated by the analysis of a simulated experiment to show the experimental requirements to recover the desired parameters. 相似文献