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1.
Skakun VV Hink MA Digris AV Engel R Novikov EG Apanasovich VV Visser AJ 《European biophysics journal : EBJ》2005,34(4):323-334
Over the last decade the number of applications of fluorescence correlation spectroscopy (FCS) has grown rapidly. Here we describe the development and application of a software package, FCS Data Processor, to analyse the acquired correlation curves. The algorithms combine strong analytical power with flexibility in use. It is possible to generate initial guesses, link and constrain fit parameters to improve the accuracy and speed of analysis. A global analysis approach, which is most effective in analysing autocorrelation curves determined from fluorescence fluctuations of complex biophysical systems, can also be implemented. The software contains a library of frequently used models that can be easily extended to include user-defined models. The use of the software is illustrated by analysis of different experimental fluorescence fluctuation data sets obtained with Rhodamine Green in aqueous solution and enhanced green fluorescent protein in vitro and in vivo.An erratum to this article can be found at
Victor V. Skakun, Mark A. Hink and Anatoli V. Digris contributed equally to this work. 相似文献
2.
It was shown on 99 male albino rats that vitamin E, sodium selenite and Astragalus. L. infusion used separately lowered the toxic effect of tetracycline on the liver, while the use of vitamin E in combination with sodium selenite or Astragalus L. infusion prevented such an effect of the antibiotic. This was evident from the decreased levels of lipid peroxidation products, i.e. diene conjugates and malonic dialdehyde in the blood and liver, and a simultaneous increase in the ratio of sulfhydryl and disulfide groups in these biosubstrates. Parallelism of the changes in these indices of the blood and liver was observed. It is suggested that lipid peroxidation plays an important part in the pathogenesis of liver affection with tetracyclines. The combined use of vitamin E and selenium-containing drugs is considered advisable for the prophylaxis and treatment of such affections. 相似文献
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A study of bacterial surface oligosaccharides were investigated among
different strains of Neisseria gonorrhoeae to correlate structural features
essential for binding to the MAb 2C7. This epitope is widely expressed and
conserved in gonococcal isolates, characteristics essential to an effective
candidate vaccine antigen. Sample lipooligosaccharides (LOS), was prepared
by a modification of the hot phenol-water method from which de-O-acetylated
LOS and oligosaccharide (OS) components were analyzed by ES-MS-CID-MS and
ES-MSnin a triple quadrupole and an ion trap mass spectrometer,
respectively. Previously documented natural heterogeneity was apparent from
both LOS and OS preparations which was admixed with fragments induced by
hydrazine and mild acid treatment. Natural heterogeneity was limited to
phosphorylation and antenni extensions to the alpha-chain. Mild acid
hydrolysis to release OS also hydrolyzed the beta(1-->6) glycosidic
linkage of lipid A. OS structures were determined by collisional and
resonance excitation combined with MS and multistep MSn which provided
sequence information from both neutral loss, and nonreducing terminal
fragments. A comparison of OS structures, with earlier knowledge of MAb
binding, enzyme treatment, and partial acid hydrolysis indicates a generic
overlapping domain for 2C7 binding. Reoccurring structural features include
a Hepalpha(1-->3)Hepbeta(1-->5)KDO trisaccharide core branched on the
nonreducing terminus (Hep-2) with an alpha(1-->2) linked GlcNAc
(gamma-chain), and an alpha-linked lactose (beta-chain) residue. From the
central heptose (Hep-1), a beta(1-->4) linked lactose (alpha-chain),
moiety is required although extensions to this residue appear unnecessary.
相似文献
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O. S. Zhdanova V. S. Kuznetsov V. A. Panarin V. S. Skakun E. A. Sosnin V. F. Tarasenko 《Plasma Physics Reports》2018,44(1):153-156
In a single-barrier discharge with voltage sharpening and low gas consumption (up to 1 L/min), plane atmospheric pressure plasma jets with a width of up to 3 cm and length of up to 4 cm in air are formed in the slit geometry of the discharge zone. The energy, temperature, and spectral characteristics of the obtained jets have been measured. The radiation spectrum contains intense maxima corresponding to vibrational transitions of the second positive system of molecular nitrogen N2 (C3Π u → B3Π g ) and comparatively weak transition lines of the first positive system of the N 2 + ion (B2Σ u + → X2Σ g ). By an example of inactivation of the Staphylococcus aureus culture (strain ATCC 209), it is shown that plasma is a source of chemically active particles providing the inactivation of microorganisms. 相似文献
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Skakun VV Novikov EG Apanasovich VV Tanke HJ Deelder AM Mayboroda OA 《European biophysics journal : EBJ》2006,35(5):410-423
The growing number of applications of Fluorescence Intensity Distribution Analysis (FIDA) demands for new approaches in data processing, aiming at increased speed and robustness. Iterative algorithms of parameter estimation, although proven to be universal and accurate, require some initial guesses (IG) of the unknown parameters. An essential component of any data processing technology, IG become especially important in case of FIDA, since even with apparently reasonable, and physically admissible but randomly chosen IG, the iterative procedure may converge to situations where the FIDA model cannot be evaluated correctly. In the present work we introduce an approach for IG generation in FIDA experiments based on the method of moments. IG are generated for the sample parameters: brightness, concentration, and for the parameters related to experimental set-up: background, observation volume profile. A number of analytical simplifications were introduced in order to increase the accuracy and robustness of the numerical algorithms. The performance of the developed method has been tested on number of simulations and experimental data. Iterative fitting with generated IG proved to be more robust and at least five times faster than with an arbitrarily chosen IG. Applicability of the proposed method for quick estimation of brightness and concentrations is discussed. 相似文献
9.
Fluorescence correlation spectroscopy (FCS) provides a versatile tool to investigate molecular interaction under native conditions,
approximating infinite dilution. One precondition for its application is a sufficient difference between the molecular weights
of the fluorescence-labelled unbound and bound ligand. In previous studies, an 8-fold difference in molecular weights or correspondingly
a 1.6-fold difference in diffusion coefficients was required to accurately distinguish between two diffusion species by FCS.
In the presented work, the hybridization of two complementary equally sized RNA single strands was investigated at an excellent
signal-to-noise ratio enabled by the highly photostable fluorophore Atto647N. The fractions of ssRNA and dsRNA were quantified
by applying multicomponent model analysis of single autocorrelation functions and globally fitting several autocorrelation
functions. By introducing a priori knowledge into the fitting procedure, 1.3- to 1.4-fold differences in diffusion coefficients
of single- and double-stranded RNA of 26, 41, and 54 nucleotides could be accurately resolved. Global fits of autocorrelation
functions of all titration steps enabled a highly accurate quantification of diffusion species fractions and mobilities. At
a high signal-to-noise ratio, the median of individually fitted autocorrelation functions allowed a robust representation
of heterogeneous data. These findings point out the possibility of studying molecular interaction of equally sized molecules
based on their diffusional behavior, which significantly broadens the application spectrum of FCS. 相似文献
10.
Here, we present an in vitro assay based on fluorescence correlation spectroscopy (FCS), which allows investigation of the kinetic behaviour of human Dicer. The assay is based on the different mobilities of substrate and product. The change of substrate mobility was independent of the choice of the fluorescence label, allowing exclusion of non-specific photophysical artefacts. Dicer and RNase III cleavage led to different product diffusion times. Single-stranded RNA did not change its mobility after cleavage by both double-strand-specific RNases. In agreement with the literature, the RNase activity of Dicer could be inhibited by substituting Ca2? for Mg2?. In a defined system of two diffusion species of similar label and mobility differences, such as substrate and product, the linearity of the assay could be proven. An FCS-based enzyme assay is proposed, which allows monitoring of Dicer activity with high specificity in vitro. 相似文献