Excited-state properties of hypericin: electronic spectra and fluorescence decay kinetics

1993 ◽  
Vol 97 (30) ◽  
pp. 7870-7875 ◽  
Author(s):  
Tomoko Yamazaki ◽  
Nobuhiro Ohta ◽  
Iwao Yamazaki ◽  
Pill Soon Song
Keyword(s):  
Excited State ◽  
Electronic Spectra ◽  
Fluorescence Decay ◽  
Decay Kinetics ◽  
Fluorescence Decay Kinetics

scholarly journals Altering the distribution of excited-state lifetimes in aminated GFP chromophores by Ag nanohole arrays

2021 ◽  
Vol 2015 (1) ◽  
pp. 012018
Author(s):  
VR Aslopovsky ◽  
AM Shakhov ◽  
AA Astafiev ◽  
VE Bochenkov
Keyword(s):  
Excited State ◽  
Rate Constants ◽  
Fluorescence Decay ◽  
Lifetime Distribution ◽  
Excited State Lifetime ◽  
Decay Kinetics ◽  
Silver Films ◽  
Nanohole Arrays ◽  
Fluorescence Decay Kinetics ◽  
Gfp Chromophore

Abstract Fluorescence of the modified GFP chromophore diethyl-ABDI-BF2 dispersed in PMMA matrix is studied on top of glass, continuous and perforated optically thin silver films. In polymer, the fluorescence decay kinetics becomes non-exponential and can be described by the distribution of rate constants. The results demonstrate shortening of the excited state lifetime in the presence of silver and broadening of the lifetime distribution caused by the nanoholes.

The tryptophan fluorescence lifetime puzzle. A study of decay times in aqueous solution as a function of pH and buffer composition

1981 ◽  
Vol 59 (7) ◽  
pp. 1037-1044 ◽  
Author(s):  
Eva Gudgin ◽  
Ricardo Lopez-Delgado ◽  
William R. Ware
Keyword(s):  
Tryptophan Fluorescence ◽  
Fluorescence Decay ◽  
Low Ph ◽  
Decay Kinetics ◽  
Decay Component ◽  
Diffusion Controlled ◽  
Double Exponential ◽  
Decay Times ◽  
Fluorescence Decay Kinetics ◽  
Buffer Composition

Tryptophan fluorescence decay kinetics have been systematically investigated in aqueous solutions as a function of pH as well as in a variety of buffer solutions. Below pH 7.0, the decay appears to be double exponential with a subnanosecond component confirming the previous findings of Rayner and Szabo (3). In the low pH region, where the proton concentration becomes kinetically significant, tryptophan fluorescence is collisionally quenched by [H+] with diffusion controlled rate and no experimental evidence is found regarding the appearance at low pH of a new tryptophan molecular species, namely the cationic form. At pH ≥ 7.0, the decay becomes triple-exponential with the appearance of a long component whose contribution to the total emission intensity increases rapidly with increasing pH at the expense of the other two. Lifetimes and relative intensities of each decay component depend in a complex way on pH and on the buffer chemical composition.

scholarly journals Evidence that D1 Processing Is Required for Manganese Binding and Extrinsic Protein Assembly into Photosystem II

2004 ◽  
Vol 279 (44) ◽  
pp. 45417-45422 ◽  
Author(s):  
Johnna L. Roose ◽  
Himadri B. Pakrasi
Keyword(s):  
Photosystem Ii ◽  
Mutant Cell ◽  
Protein A ◽  
D1 Protein ◽  
Fluorescence Decay ◽  
Normal Function ◽  
Temporal Position ◽  
Decay Kinetics ◽  
Fluorescence Decay Kinetics ◽  
Extrinsic Proteins

Photosystem II (PSII) is a large membrane protein complex that catalyzes oxidation of water to molecular oxygen. During its normal function, PSII is damaged and frequently turned over. The maturation of the D1 protein, a key component in PSII, is a critical step in PSII biogenesis. The precursor form of D1 (pD1) contains a C-terminal extension, which is removed by the protease CtpA to yield PSII complexes with oxygen evolution activity. To determine the temporal position of D1 processing in the PSII assembly pathway, PSII complexes containing only pD1 were isolated from a CtpA-deficient strain of the cyanobacteriumSynechocystis6803. Although membranes from the mutant cell had nearly 50% manganese, no manganese was detected in isolated ΔctpAHT3 PSII, indicating a severely decreased manganese affinity. However, chlorophyll fluorescence decay kinetics after a single saturating flash suggested that the donor YZwas accessible to exogenous Mn2+ions. Furthermore, the extrinsic proteins PsbO, PsbU, and PsbV were not present in PSII isolated from this mutant. However, PsbO and PsbV were present in mutant membranes, but the amount of PsbV protein was consistently less in the mutant membranes compared with the control membranes. We conclude that D1 processing precedes manganese binding and assembly of the extrinsic proteins into PSII. Interestingly, the Psb27 protein was found to be more abundant in ΔctpAHT3 PSII than in HT3 PSII, suggesting a possible role of Psb27 as an assembly factor during PSII biogenesis.

scholarly journals Analysis of Fluorescence Decay Kinetics of Indocyanine Green Monomers and Aggregates in Brain Tumor Model In Vivo

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3185
Author(s):  
Dina Farrakhova ◽  
Igor Romanishkin ◽  
Yuliya Maklygina ◽  
Lina Bezdetnaya ◽  
Victor Loschenov
Keyword(s):  
Brain Tumor ◽  
Indocyanine Green ◽  
Fluorescence Lifetime ◽  
Tumor Model ◽  
Fluorescence Decay ◽  
Decay Kinetics ◽  
Lifetime Analysis ◽  
Fluorescence Decay Kinetics ◽  
Brain Tumor Model

Spectroscopic approach with fluorescence time resolution allows one to determine the state of a brain tumor and its microenvironment via changes in the fluorescent dye’s fluorescence lifetime. Indocyanine green (ICG) is an acknowledged infra-red fluorescent dye that self-assembles into stable aggregate forms (ICG NPs). ICG NPs aggregates have a tendency to accumulate in the tumor with a maximum accumulation at 24 h after systemic administration, enabling extended intraoperative diagnostic. Fluorescence lifetime analysis of ICG and ICG NPs demonstrates different values for ICG monomers and H-aggregates, indicating promising suitability for fluorescent diagnostics of brain tumors due to their affinity to tumor cells and stability in biological tissue.

scholarly journals Examination of chlorophyll fluorescence decay kinetics in sulfur deprived algae Chlamydomonas reinhardtii

2007 ◽  
Vol 1767 (6) ◽  
pp. 559-564 ◽  
Author(s):  
A.A. Volgusheva ◽  
V.E. Zagidullin ◽  
T.K. Antal ◽  
B.N. Korvatovsky ◽  
T.E. Krendeleva ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlamydomonas Reinhardtii ◽  
Fluorescence Decay ◽  
Decay Kinetics ◽  
Fluorescence Decay Kinetics
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