scholarly journals Evaluation of Fluorescent Analogs of Deoxycytidine for Monitoring DNA Transitions from Duplex to Functional Structures

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Yogini P. Bhavsar ◽  
Samantha M. Reilly ◽  
Randy M. Wadkins
Keyword(s):  
Fluorescence Spectra ◽  
Helical Structure ◽  
Spectroscopic Studies ◽  
Structural Transitions ◽  
Fluorescent Properties ◽  
Common Pathway ◽  
Dna Structures ◽  
Functional Dna ◽  
Lifetime Studies ◽  
Affect Gene Expression

Topological variants of single-strand DNA (ssDNA) structures, referred to as “functional DNA,” have been detected in regulatory regions of many genes and are thought to affect gene expression. Two fluorescent analogs of deoxycytidine, Pyrrolo-dC (PdC) and 1,3-diaza-2-oxophenoxazine (t), can be incorporated into DNA. Here, we describe spectroscopic studies of both analogs to determine fluorescent properties that report on structural transitions from double-strand DNA (dsDNA) to ssDNA, a common pathway in the transition to functional DNA structures. We obtained fluorescence-detected circular dichroism (FDCD) spectra, steady-state fluorescence spectra, and fluorescence lifetimes of the fluorophores in DNA. Our results show that PdC is advantageous in fluorescence lifetime studies because of a distinct ~2 ns change between paired and unpaired bases. However, t is a better probe for FDCD experiments that report on the helical structure of DNA surrounding the fluorophore. Both fluorophores provide complementary data to measure DNA structural transitions.

scholarly journals Spectroscopic Studies of Dual Fluorescence in 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole: Effect of Molecular Aggregation in a Micellar System

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2861 ◽  
Author(s):  
Grzegorz Czernel ◽  
Arkadiusz Matwijczuk ◽  
Dariusz Karcz ◽  
Andrzej Górecki ◽  
Agnieszka Niemczynowicz ◽  
...  
Keyword(s):  
Light Scattering ◽  
Fluorescence Spectra ◽  
Single Photon ◽  
Spectroscopic Studies ◽  
Fluorescence Probes ◽  
Molecular Aggregation ◽  
Micellar System ◽  
Dual Fluorescence ◽  
Fluorescence Measurements ◽  
Ionic Detergent

The article presents the results of spectroscopic studies focused on a selected compound from the 1,3,4-thiadiazole group—2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thia-diazole (FABT)—in a micellar system formed by Triton X-100, a non-ionic detergent. Fluorescence measurements revealed the phenomenon of dual fluorescence whose emergence is related to the particular molecular organisation of the compound, which depends both on the concentration of the detergent and, most of all, the concentration of the compound itself. Dual fluorescence of FABT in a micellar system was observed for the compound dissolved in a methanol aqueous system, i.e., an environment wherein the dual fluorescence of the compound had never been reported before. Based on the interpretation of UV-Vis electronic absorption, resonance light scattering (RLS), emission and excitation fluorescence spectra, as well as measurements of dynamic light scattering (DLS) and Principal Component Analysis (PCA), we were able to relate the occurrence of this effect to the process of molecular aggregation taking place between FABT molecules in the micellar system in question. Results of fluorescence spectra measurements and time-correlated single photon counting (TCSPC) indicate that dual fluorescence occurs at detergent concentrations necessary to form micellar systems, which in turn facilitate the process of aggregation of FABT molecules. The correlation between the observed fluorescence effects and the previous measurements performed for analogues from this group suggests the possibility of charge transfer (CT) within the range of detergent concentrations wherein the aforementioned fluorescence effects are observed. It ought to be emphasised that this type of fluorescence effects are relatively easy to induce, which predisposes this groups of fluorophores as ideal fluorescence probes in the context of biological samples.

scholarly journals Luminescent Hybrid Materials Based on Curcumin Derivatives Embedded in Palygorskite

2018 ◽  
Vol 55 (1) ◽  
pp. 63-67
Author(s):  
Monica Florentina Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Luminita Eugenia Wagner ◽  
Viorica Amariutei ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Hydroxyl Groups ◽  
Fluorescent Properties ◽  
Fluorescence Emission Spectra ◽  
Curcumin Derivatives ◽  
Absorption Studies ◽  
Inorganic Matrix

The seven curcumin derivatives were deposited on palygorskite in order to obtain hybrid materials. The fluorescence emission spectra of the obtained materials show a decrease in fluorescence intensity relative to the respective dyes, due to the environments around the dyestuff molecules created in the host matrices. Absorption studies show the best adsorption on the inorganic matrix, for the compounds with the hydroxyl groups. Correlating fluorescence spectra of hybrid materials with the results for absorption spectra of the dyes adsorbtion on the surface of the clay lead to the conclusion that a high percentage of the adsorbed dye had the effect of fluorescence quenching. Thus, it was confirmed that the fluorescent properties of hybrid materials depend on the interactions established between the fluorescent dyestuff and the inorganic network.

Study on Photochromic Materials with a Novel Photochromic Diarylethene use for Polarization Holographic Recording

2013 ◽  
Vol 763 ◽  
pp. 61-64 ◽  
Author(s):  
Shang Hua He ◽  
Gang Liu ◽  
Shi Qiang Cui
Keyword(s):  
Fluorescence Spectra ◽  
Uv Light ◽  
Amorphous Film ◽  
Quantum Yields ◽  
Holographic Recording ◽  
Pmma Film ◽  
Recording Medium ◽  
Fluorescent Properties ◽  
Image Recording ◽  
Photochromic Materials

A novel unsymmetrical photochromic diarylethene 1-(2, 5-dimethyl-3-thienyl)-2-[2-methyl-5-(2,2-dibutylfluorene)-3-thienyperfluorocyclo-pentene (1o) was synthesized and its photochromic and fluorescent properties were investigated. Diarylethene 1 changed the color from colorless to hyacinthine upon irradiation with 297 nm UV light, in which absorption maxima were observed at 554 nm in hexane and at 565 nm in PMMA amorphous film, respectively. This new photochromic system also exhibited remarkable fluorescence intensity both in solution and in PMMA film. The fluorescence spectra showed a systematic red-shift with the emission intensity of diarylethene 1 in a photo-stationary state was quenched to ca. 64%. The cyclization and cycloreversion quantum yields of 1 in hexane were determined to be 0.56 and 0.002. Polarization multiplexed image recording can be carried out in this diarylethene 1c/PMMA film as recording medium film.

scholarly journals Conformational studies of biliproteins from the insects pieris brassicae and cerura vinula

1988 ◽  
Vol 43 (1-2) ◽  
pp. 84-90 ◽  
Author(s):  
Hugo Scheer ◽  
Hartmut Kayser
Keyword(s):  
Circular Dichroism ◽  
Optical Activity ◽  
Fluorescence Spectra ◽  
Protein A ◽  
Protein Secondary Structure ◽  
Helical Structure ◽  
Pieris Brassicae ◽  
Bile Pigments ◽  
Urea Denaturation ◽  
Circular Dichroïsm

Chromophore conformation and protein secondary structure of biliproteins from the butterfly, Pieris brassicae, and the moth, Cerura vinula, have been investigated by absorption, circular dichroism and fluorescence spectroscopy. The chromophore of the P. brassicae protein, biliverdin IXy, has probably a cyclic-helical structure similar to that of free bile pigments of the biliverdin type. Though achiral by structure the chromophore displays strong optical activity in the native protein-bound state, but becomes inactive after urea denaturation of the protein. A minor biliprotein from P. brassicae shows absorption, circular dichroism and fluorescence spectra identical to the main biliprotein. In the biliprotein from Cerura vinula the structure of the pigment is still unknown. It has a semi-open conformation intermediate between that of the Pieris proteins and that of the phycobiliprotein, C-phycocyanin, and it retains optical activity after urea denaturation. The band widths and the size of the Stokes shifts of the fluorescence spectra indicate a high degree of conformational flexibility of the chromophores in the two Pieris pigments, and a decreased flexibility in the one from Cerura. In the biliproteins from both insects the polypeptides are low in a-helix content compared to that of phycobiliproteins. From these and earlier data, insect and algal biliproteins seem to be related only distantly if at all, but there exist also considerable differences among insect biliproteins from different species

Spectroscopic Studies on Dyes. IV. The Fluorescence Spectra of Thioindigo Dyes1

1957 ◽  
Vol 79 (10) ◽  
pp. 2464-2468 ◽  
Author(s):  
Delbert A. Rogers ◽  
J. David Margerum ◽  
George M. Wyman
Keyword(s):  
Fluorescence Spectra ◽  
Spectroscopic Studies

Microsatellite variation associated with prolactin expression and growth of salt-challenged tilapia

2002 ◽  
Vol 9 (1) ◽  
pp. 1-4 ◽  
Author(s):  
J. T. Streelman ◽  
T. D. Kocher
Keyword(s):  
Gene Expression ◽  
Simple Sequence Repeat ◽  
Growth Response ◽  
Regulatory Evolution ◽  
Microsatellite Variation ◽  
Dna Structures ◽  
Microsatellite Alleles ◽  
Affect Gene Expression ◽  
Simple Sequence

Biologists have long argued that runs of alternating purines and pyrimidines could form alternative DNA structures, which might regulate transcription. Here, we report that simple sequence repeat polymorphisms in the tilapia prolactin 1 ( prl 1) promoter are associated with differences in prl 1 gene expression and the growth response of salt-challenged fishes. Individuals homozygous for long microsatellite alleles express less prl 1 in fresh water but more prl 1 in half-seawater than fishes with other genotypes. Our work provides the first in vivo evidence that differences in microsatellite length among individuals may indeed affect gene expression and that variance in expression has concomitant physiological consequences. These results suggest that dinucleotide microsatellites represent an under-appreciated source of genetic variation for regulatory evolution.

scholarly journals Biomimetic Design of a Robustly Stabilized Folded State Enabling Seed-Initiated Helical Supramolecular Polymerization Under Microfluidic Mixing

2020 ◽  
Author(s):  
Soichiro Ogi ◽  
Aiko Takamatsu ◽  
Kentaro Matsumoto ◽  
Shigehiro Yamaguchi
Keyword(s):  
Molecular Diffusion ◽  
Helical Structure ◽  
Spectroscopic Studies ◽  
Membered Ring ◽  
Racemic Mixture ◽  
Supramolecular Polymer ◽  
Spontaneous Transformation ◽  
Microfluidic Mixing ◽  
Intramolecular Hydrogen ◽  
Supramolecular Polymerization

We have investigated the folding and assembly behavior of an alanine-based monomeric diamide and a cystine-based dimeric diamide bearing pyrene units and solubilizing alkyl chains at their C-termini andN-termini, respectively. In low-polarity solvents, the former molecule forms a folded 7-membered ring conformation with an intramolecular hydrogen bond, while the latter molecule forms a 14-membered ring through double intramolecular hydrogen bonds between two diamide units. Spectroscopic studies revealed that both folded states are thermodynamically unstable and eventually transform into more energetically stable supramolecular polymers. Importantly, compared to the alanine-based diamide, the cystine-based dimeric diamide exhibits a superior kinetic stability in the metastable folded state, as well asan increased thermodynamic stability in the aggregated state. Consequently, spontaneous transformation from the folded state into the aggregated state is retarded even under the conditions of rapid molecular diffusion. Accordingly, the initiation of supramolecular polymerization can be regulated via a seeding approach under microfluidic mixing conditions. Furthermore, the supramolecular polymer composed of the cystine-based dimeric diamide has a helical structure with an enhanced chiral excitonic coupling between the transition dipoles of the pyrene units. Taking advantage of the self-sorting behavior observed in a mixture of l-cysteine- and d-cysteine-based dimeric diamides, a two-step supramolecular polymerization from a racemic mixture was achieved by stepwise addition of the corresponding seeds.

Spectroscopic Studies of Dimethylamino Derivatives of Fluorene

2000 ◽  
Vol 55 (11-12) ◽  
pp. 902-908 ◽  
Author(s):  
J. Heldt ◽  
J. R. Heldt ◽  
T. Redzimski ◽  
H. Diehl ◽  
P. Schultz
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Fluorescence Spectra ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Spectroscopic Studies ◽  
Polar Solvents ◽  
Derivatives Of ◽  
Transfer State

Abstract 2-dimethylamino-9-fluorenol and 2-dimethylamino-9(4'dimethylamino)phenyl-9-fiuorenol in polar solvents in the excited state undergo conformation changes in which two fluorescent isomers are created. The isomers (in the local excited (LE) and charge transfer (CT) configuration) possess separate fluorescence bands, one appearing from the S1 (LE) state and the second from the intramolecular charge transfer state S1 (CT) of the neutral, aromatic molecule. Both bands show a solvatochromic effect. Using the method of the solvent induced Stokes shift of the absorption and fluorescence spectra the permanent dipole moment of the excited state of fluorene and its two derivatives have been determined. The dipole moment of the ground state and the Onsager cavity radius of the studied molecules were calculated with the Auestion Model 1 (AM1) program.

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