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Introduction to Biological Light Microscopy
Published in Jay L. Nadeau, Introduction to Experimental Biophysics, 2017
Jay L. Nadeau, Michael W. Davidson
Several of the acridine dyes, first isolated in the nineteenth century, are useful as fluorescent probes in confocal microscopy. The most widely utilized, acridine orange, consists of the basic acridine nucleus with dimethylamino substituents located at the 3 and 6 positions of the tri-nuclear ring system. In physiological pH ranges, the molecule is protonated at the heterocyclic nitrogen and exists predominantly as a cationic species in solution. Acridine orange binds strongly to DNA by intercalation of the acridine nucleus between successive base pairs, and exhibits green fluorescence with a maximum wavelength of 530 nm. The probe also binds strongly to RNA or single-stranded DNA, but has a longer wavelength fluorescence maximum (approximately 640 nm; red) when bound to these macromolecules. In living cells, acridine orange diffuses across the cell membrane (by virtue of the association constant for protonation) and accumulates in the lysosomes and other acidic vesicles. Similar to most acridines and related polynuclear nitrogen heterocycles, acridine orange has a relatively broad absorption spectrum, which enables the probe to be used with several wavelengths from the argon-ion laser. It is highly phototoxic and will kill cells after several minutes of imaging.
Selection and Improvement of Industrial Organisms for Biotechnological Applications
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
Acridine, C13H9N, is an organic compound consisting of three fused benzene rings. Acridine is colorless and was first isolated from crude coal tar. It is a raw material for the production of dyes. Acridines and their derivatives are DNA and RNA binding compounds due to their intercalation abilities. Acridine Orange (3,6-dimethylaminoacridine) is a nucleic acid selective metachromatic stain useful for cell cycle determination.
One-pot construction of gemcitabine loaded zeolitic imidazole framework for the treatment of lung cancer and its apoptosis induction
Published in Journal of Experimental Nanoscience, 2023
Zhan Li, Tiantian Du, Wen Yang, Shenni Yi, Na Zhang
Therapeutic anticancer drugs may aim to kill cancer cells by stimulating their apoptotic process. Alterations in cell morphology and discovering apoptotic cell death can be shown using dual labelling using nucleic acid binding dyes like acridine orange (AO) and ethidium bromide (EB), which rely on fluorescence emission to identify the phenomenon. This reveals the mechanism by which synthetic complexes inhibit cancer cell proliferation and kill them. Changes in cell structure, such as cytoplasmic shrinkage, nuclear condensation, plasma membrane blebbing, DNA breakage and translocation of phosphatidylserine to the extracellular side, are diagnostic of cells that have been induced to undergo apoptosis [50–52]. Both live and dead cells are stained with acridine orange during the fluorescence staining procedure. Ethidium bromide, conversely, stains cells with compromised membranes. Through a fluorescence microscope, living cells appear green. Although they stain red, necrotic cells have a nucleus structure not dissimilar to that of healthy ones. Cells undergoing the morphological alterations linked with apoptosis appear as reddish-orange areas. Our experiment’s control cells are alive, have a normal, well-ordered structure, green shine and consistently emit green fluorescence. The A549 and H1299 cells stained with AO-EB were exposed to the ZIF-L, GEM and GEM@ZIF-L. By disrupting the membrane of cancer cells, the novel chemicals promoted apoptosis, with EB penetrating the cells to obscure AO fluorescence and generate a greenish-orange stain. ZIF-L, GEM and GEM@ZIF-L, as found in Figure 8A, trigger cell death. GEM@ZIF-L shows a high level of apoptosis compared to the free ZIF-L and GEM. The quantified ratio of the morphological changes during cell death is shown in Figure 8B.
Microbiologically influenced corrosion of ferritic steel–zirconium-based metal waste form alloy under simulated geological repository environment
Published in Corrosion Engineering, Science and Technology, 2018
R. Priya, R. P. George, K. Thyagarajan, S. Ningshen
MWF specimen exposed in the bacterial culture was used for direct microscopic observation using Nikon Eclipse E600 Epifluorescence Microscope. The biofilmed specimen was washed with sterile buffer to remove loosely adhered cells and after drying was immersed in a nucleic acid staining solution of acridine orange (0.1%). The specimen was taken out after 1 h and washed in sterile buffer solution and dried. Acridine orange is a fluorescent nucleic acid dye that can differentially stain single-stranded RNA as fluorescing orange and double-stranded DNA as fluorescing green [37].