Wyniki wyszukiwania - Biblioteka Nauki

1

Computer studies of fluorescein-PE-interaction with the lipid bilayer

100%

Kubica K.

Cellular and Molecular Biology Letters

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2002

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tom 07

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nr Suppl.

2

Excited State Proton Transfer Reaction in a New Benzofuryl 3-Hydroxychromone Derivative: The Influence of Low-Polar Solvents

86%

Demchenko A. , Ercelen S. , Roshal A. D. , Klymchenko A. S.

Polish Journal of Chemistry

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2002

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tom Vol. 76 / nr 9

1287-1299

EN

Unique properties of a new 3-hydroxychromone derivative 2-(6-diethylaminobenzo[ b]furan-2-yl)-3-hydroxychromone (FA) in its ability to exhibit excited-state intramolecular proton transfer (ESIPT) reaction are described. In contrast to all other chromone and flavone derivatives studied, in low-polar solvents it exhibits in emission, together with the tautomer (T*) band, an intensive band of the normal (N*) form. Previously the intensive N* form in emission was observed only in highly polar, mostly protic solvents. While its absorption spectra are sensitive to H-bond acceptor properties of the solvent, the fluorescence spectra are not. This suggests that intermolecular H-bonds with a solvent, if they exist in the ground state, are reorganized in the excited state in favor of intramolecular bond, which is the pathway for ESIPT reaction. The energy difference, _N* - _T*, between N* and T* emission maxima is in almost ideal correlation with the Reichardt solvatochromic parameter EN T . This suggests the use of FAas a highly sensitive polarity sensor.Agood correlation between _N* - _T*, and the ratio of the N* and T* band intensities is observed. This allows to observe the solvent effects on a manifold increased level of sensitivity. The analysis based on Lippert and Bakhshiev equations and the quantum- chemical calculations suggest a substantial increase of the dipole moment on electronic excitation to the N* state. The appearance of the N* form in emission may be the result of its dielectric stabilization.

3

Photoproduction of organic peroxides on the donor side of photosystem II after destruction of the water-oxidizing complex

72%

Khorobrykh A. , Khorobrykh S. , Yanykin D. , Ivanov B. , Klimov V. , Mano J.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2013

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tom 94

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nr 2

4

Sensitive fluorimetric determination of protein with dibromohydroxyphenylfluorone-molybdenum(VI) comlex probe based on fluorescence quenching in non-ionic microemulsion

72%

Wei Q. , Li Y. , Yan T. , Duan C. , Ma H. , Bin D.

Chemia Analityczna

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2006

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tom Vol. 51, No. 5

691-700

EN

In this paper binding interaction between a new fluorescence probe dibromohydroxyphenyi-fluoronc-molybdenum(VI) (DBHPF-Mo(Vl) and a protein has been studied. In the presence of the cmulsifier OP microemulsion of pH 3.2 DBHPF-Mo(VI) complex binds the protein rapidly to form a stable compound of a maximum excitation wavelength (λex) of 468 nm and a maximum emission wavelength (λcm) of 527 nm. Fluorescence intensity of the probe is quenched by the protein. The magnitude of quenching is linearly proportional to the protein concentration. Under optimum conditions calibration plots for bovine serum albumin (BSA), human serum albumin (USA), and ovalburnin (Ova) have been constructed in the concentration ranges of 0∼6.00 μg mL-1, 0∼4.00 μg mL-1 and 0∼4.00 -1 , respectively. Addition of the OP microemulsion to the system during protein determination has increased significantly the sensitivity of the analysis by changing the microenvi-ronment. The corresponding detection limits of BSA, HSA and Ova were 3.4 ng mL-1, 3.6 ng mL-1 and 6.2 ng mL-1 The developed procedure has been satisfactorily applied to the determination of protein in urine.

PL

Zbadano oddziaływanie nowego odczynnika fluorescencyjnego: dibromohydroksyfluoron-molibden(VJ) (DBHPF-Mo(VI) z białkiem, W obecności emulgatora OP, przy pH 3,2 mikroemulsja kompleksu DBHPF-Mo(Vl) wiąże szybko białko, tworząc trwale połączenie o długości fali promieniowania wzbudzającego 468 nm i emitowanego 527 nm. Intensywność fiuorescencj i jest tłumiona w obecności białka. Wielkość tłumienia jest liniowo proporcjonalna do stężenia białka. W optymalnych warunkach otrzymano wykresy kalibracyjne dla albuminy surowicy wołowej (BSA), albuminy surowicy ludzkiej (HSA) i owalbuminy (Ova) w zakresach odpowiednio: 0∼6.00 μg mL-1, 0∼4.00 μg mL-1. Dodatek emulgatora OP zwiększa znacznie czułość metody. Granice wykrywalności BSA. HSA i Ova wy noszą odpowiednio mL-1, 3.6 ng mL-1 and 6.2 ng mL-1 . Opracowaną procedurę zastosowano do oznaczania białka w moczu.

5

Rhodamine-6G hydrazide probe for selective determination of Cu(II) in aqueous media

72%

Wang P. , Wu G. , Gu Z. , Wu D. , He C.

Chemia Analityczna

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2009

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tom Vol. 54, No. 2

151-162

EN

A new fluorescence method for selective determination of Cu24 using rhodamine 6G hydra-zide (R6GH) as a probe has been developed. The probe has shown selective and sensitive fluorescence response toward Cu2+ in aqueous media. In the proposed reaction mechanism the hydrazide group of R6GH binds to Cu2+ exhibiting a behavior similar to a-amino esters, which results in a redox hydrolysis of the hydrazide moiety with the release of highly fluorescent rhodamine 6G. Under the optimal conditions the fluorescence enhancement at 545 nm was linearly related to the concentration of Cu2+ in the range 0.1-10 μ mol L-1 The proposed method has been applied to the determination of trace Cu-2 in water samples with satisfactory results.

PL

Opracowano nową fluorescencyjną metodę selektywnego oznaczania Cu-2 używając hydrazydku rodaminy 6G (R6GH) jako sondy. Sonda wykazała selektywną i czułą fluoroscencyjną reakcję na obecność Cu-2 w wodnym roztworze. Zaproponowano mechanizm reakcji, w którym grupa hydrazydkowa w R6GH łączy się z Cu-1 i wykazuje zachowanie podobne do a-amino estrów co prowadzi do hydrolizy red-oks i wydzielenia wysoko fluoryzującej rodaminy 6G. W warunkach optymalnych wzrost fluorescencji przy 545 nm był liniowo zależny od stężenia Cu-2 w zakresie 0,1-10 μ mol L-1. Zaproponowaną metodę zastosowano do oznaczania śladów Cu-2 w próbkach wód uzyskując dobre wyniki.

6

Estimation of the organotin compounds partition into phosphatidylcholine bilayers with a pH sensitive fluorescence probe

72%

Langner M. , Kleszczynska H.

Cellular and Molecular Biology Letters

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1997

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tom 02

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nr 1

EN

The relative partition of trialkyltin and dialkyltin chlorides into the phosphatidylcholine membrane was estimated with a fluorescein dye attached to the phosphatidylethanolamine headgroup (Fluorescein-PE). Changes of pH in the vicinity of the membrane, caused by the adsorption of charged organotin compounds onto the surface, are measured with Fluorescein-PE. Measurements show that dialkyltin and trialkyltin chlorides at low concentrations (below 4 µM) adsorb onto the membrane surface in the charged form and that their relative partition depends on the length of the hydrocarbon residues. Tributyltin chloride was found to be the exception. Its effect on Fluorescein-PE fluorescence in the lipid bilayer was a complex dependence on its concentration in the sample, suggesting conformational changes in the lipid bilayer.

7

Fluorescencyjne nanolipopolimersomy jako bezpieczne kontrasty w diagnostyce medycznej

58%

Sierant M. , Miksa B.

Przetwórstwo Tworzyw

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2014

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tom [R.] 20, nr 1 (157)

88--91

PL

Przedmiotem badań była synteza biokompatybilnych kapsułek polimerowych, które mogłyby spełniać rolę sondy fluorescencyjnej wykorzystywanej jako kontrasty w żywych komórkach. Otrzymaliśmy nanolipopolimersomy otoczone fluorescencyjną powłoką z usieciowanego polistyrenu z dodatkiem kumaryny 6. Wykazaliśmy na przykładzie barwników (Procion red, Procion blue, Lucifer yellow), że możliwa jest enkapsulacja hydrofilowych związków we wnętrzu trwałych, polimerowych pęcherzyków. Opracowana przez nas uniwersalna metoda syntezy stabilnych nanokapsułek wykorzystujących nietrwałe struktury liposomów może znaleźć szerokie zastosowanie w diagnostyce medycznej do transportu wielu substancji aktywnych oraz monitorowania ich lokalizacji w komórkach.

EN

In our research we synthesized biocompatible probes for developing a stable macromolecule imaging system using nanolipopolymersomes in living cells. We prepared polymer vesicles with a fluorescent wall surrounded by on outer phospholipids shell suitable for dual detection (spectrophotometric and fluorescence). We developed highly fluorescent coumarinated poly(styrene-co-divinylbenzene) capsules with encapsulated hydrophilic dyes (Procion Red, Procion blue, Lucifer yellow). Our method of synthesis novel fluorescent hybrid materials can help in medical diagnostics, which can be uses in studies of the transport routs in living cells.

8

Hydroxypropylcellulose-graft-poly(N-isopropylacrylamide)—novel water-soluble copolymer with double thermoresponsivity

58%

Motyl M. , Drozd D. , Kamiński K. , Bielska D. , Karewicz A. , Szczubiałka K. , Nowakowska M.

Polimery

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2013

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tom T. 58, nr 9

696--702

EN

Acopolymer showing two cloud points was obtained by grafting poly(N-isopropylacrylamide) (PNIPAM) onto hydroxypropylcellulose (HPC). The structure of the polymer was verified using 1H NMR, FT-IR, GPC, and elemental analysis. The values of cloud points could be changed by increasing ionic strength and as a result of the interactions with surfactants.

PL

Metodą naszczepienia poli(N-izopropyloakryloamidu) (PNIPAM) na hydroksypropylocelulozie (HPC) otrzymano kopolimer wykazujący dwa punkty zmętnienia. Strukturę polimeru potwierdzono wykorzystując badania metodami 1H NMR, FT-IR, GPC oraz analizy elementarnej. Wartości temperatury w punktach zmętnienia ulegały zmianie w wyniku siły jonowej oraz w wyniku oddziaływań z surfaktantami.

9

Interaction of selected anthocyanins with erythrocytes and liposome membranes

58%

Bonarska-Kujawa D. , Pruchnik H. , Kleszczynska H.

Cellular and Molecular Biology Letters

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2012

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tom 17

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nr 2

EN

Anthocyanins are one of the main flavonoid groups. They are responsible for, e.g., the color of plants and have antioxidant features and a wide spectrum of medical activity. The subject of the study was the following compounds that belong to the anthocyanins and which can be found, e.g., in strawberries and chokeberries: callistephin chloride (pelargonidin-3-O-glucoside chloride) and ideain chloride (cyanidin-3-O-galactoside chloride). The aim of the study was to determine the compounds’ antioxidant activity towards the erythrocyte membrane and changes incurred by the tested anthocyanins in the lipid phase of the erythrocyte membrane, in liposomes composed of erythrocyte lipids and in DPPC, DPPC/cholesterol and egg lecithin liposomes. In particular, we studied the effect of the two selected anthocyanins on red blood cell morphology, on packing order in the lipid hydrophilic phase, on fluidity of the hydrophobic phase, as well as on the temperature of phase transition in DPPC and DPPC/cholesterol liposomes. Fluorimetry with the Laurdan and Prodan probes indicated increased packing density in the hydrophilic phase of the membrane in the presence of anthocyanins. Using the fluorescence probes DPH and TMA-DPH, no effect was noted inside the hydrophobic phase of the membrane, as the lipid bilayer fluidity was not modified. The compounds slightly lowered the phase transition temperature of phosphatidylcholine liposomes. The study has shown that both anthocyanins are incorporated into the outer region of the erythrocyte membrane, affecting its shape and lipid packing order, which is reflected in the increasing number of echinocytes. The investigation proved that the compounds penetrate only the outer part of the external lipid layer of liposomes composed of erythrocyte lipids, DPPC, DPPC/cholesterol and egg lecithin lipids, changing its packing order. Fluorimetry studies with DPH-PA proved that the tested anthocyanins are very effective antioxidants. The antioxidant activity of the compounds was comparable with the activity of Trolox®.