A Flash Photolysis Study of the Triplet State of Acridine Orange in Basic Solvents

Kellmann, A.

doi:10.1111/j.1751-1097.1971.tb06155.x

Cited by 24 publications

(25 citation statements)

References 16 publications

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“…The triplet-triplet absorption spectrum of 3 A 0 in methanol containing 2 mM sodium methylate (see Fig. 1) shows two maxima at 410 and 550 nm, similar to those obtained in water at pH 12 (Kellmann, 1971). On reducing the pHM the spectrum changes due to the protonation of 'AO.…”

Section: Resu L1ssupporting

confidence: 59%

“…The bimolecular quenching constants are in good agreement with those obtained by Pugachew et al (1974) in water. In the bimolecular triplet quenching electron transfer is involved, indicated by the production of semireduced radicals (Kellmann, 1971(Kellmann, , 1974. Figure 1 Triplet -triplet absorption spectra of 3 A 0 (-----) and 'AOH' (--) in methanol, A 0 3-6 p M , 2 m M sodium methylate AOH' 2-4 p M , 1 mM CI-acetic acid.…”

Section: Resu L1smentioning

confidence: 99%

“…Two species with different absorption spectra have been reported in water (Kellmann, 1971(Kellmann, , 1974 at pH 12 with a maximum at 405nm and at pH 3 with a maximum at 360nm. It was not possible to find another semireduced form in aqueous solution in the pH range 3-14.…”

Section: Protolytic Equilihriuni Of Sernireditced Acridinc Orangc' Fmentioning

confidence: 99%

“…On the other hand, with experimentally determined value of AGh -AG", pKrpKs can be estimated. Two conjugate triplet forms of acridine orange which are present in basic and weakly acidic aqueous solution, have been studied intensively by Kellmann (1971Kellmann ( , 1974. However, little is known about triplet reactivity.…”

Section: Introd Uctlonmentioning

confidence: 99%

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Reactivity of Acridine Dye Triplet States in Electron Transfer Reactions

Vogelmann

Rauscher

Krameer

1979

Photochem & Photobiology

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Abstract—Rate constants, kq, for the reaction of cationic and neutral acridine orange and 10‐methylacridine orange triplet states (3AOH +, 3AO, 3MAO+) with a series of electron donors have been measured. Two different protolytic forms of the semireduced dye radical are produced by acridine orange triplet quenching at various pHM values in methanolic solution. It is found that k4 decreases with increasing oxidation potential of the reducing agent for all triplet states in a manner which is expected for electron transfer reactions. The different reactivities of the cationic and neutral triplet forms can, therefore, be attributed to the difference in reduction potentials of these species. The difference in reduction potentials is related to the pKM values of triplet state, pKTM, and semireduced dye radical, pKMS, by thermodynamic consideration. pKTM (3AOH+/3AO) is determined to be 11.2. From thispKSM (AOH./AO;) is estimated to be 17–18. This is in striking contrast to the protolytic equilibrium of the semireduced dye radicals found to be pKF= 4.1. We conclude that the last value represents the second protonation equilibrium (AOH+2./AOH). This conclusion is confirmed by spectroscopic data.

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Section: Resu L1ssupporting

confidence: 59%

Section: Resu L1smentioning

confidence: 99%

Section: Protolytic Equilihriuni Of Sernireditced Acridinc Orangc' Fmentioning

confidence: 99%

Section: Introd Uctlonmentioning

confidence: 99%

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Reactivity of Acridine Dye Triplet States in Electron Transfer Reactions

Vogelmann

Rauscher

Krameer

1979

Photochem & Photobiology

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“…Significant phototoxicity is probably a result of efficient generation of singlet oxygen in the presence of the stacked, redemitting form of the dye which is known to have a long triplet state (19,20). Imaging is also complicated by fluorescent signal from RNA-bound AO in the cytoplasm which degrades image contrast and renders small weakly stained vesicles undetectable.…”

Section: Advantages and Shortcomings Of Ao Lysotracker And Qa Labelmentioning

confidence: 99%

Evaluation of acridine orange, LysoTracker Red, and quinacrine as fluorescent probes for long‐term tracking of acidic vesicles

2014

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Acidic vesicles can be imaged and tracked in live cells after staining with several low molecular weight fluorescent probes, or with fluorescently labeled proteins. Three fluorescent dyes, acridine orange, LysoTracker Red DND-99, and quinacrine, were evaluated as acidic vesicle tracers for confocal fluorescence imaging and quantitative analysis. The stability of fluorescent signals, achievable image contrast, and phototoxicity were taken into consideration. The three tested tracers exhibit different advantages and pose different problems in imaging experiments. Acridine orange makes it possible to distinguish acidic vesicles with different internal pH but is fairly phototoxic and can cause spectacular bursts of the dye-loaded vesicles. LysoTracker Red is less phototoxic but its rapid photobleaching limits the range of useful applications considerably. We demonstrate that quinacrine is most suitable for long-term imaging when a high number of frames is required. This capacity made it possible to trace acidic vesicles for several hours, during a process of drug-induced apoptosis. An ability to record the behavior of acidic vesicles over such long periods opens a possibility to study processes like autophagy or long-term effects of drugs on endocytosis and exocytosis. V C 2014International Society for Advancement of Cytometry

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