Acridine orange

Acridine Orange BaseAcridine Orange NOBasic Orange 14EuchrysineRhoduline OrangeRhoduline Orange NRhoduline Orange NOSolvent Orange 15Acridine orange is an organic compound. It is used as a nucleic acid-selective fluorescent cationic dye useful for cell cycle determination. Being cell-permeable, it interacts with DNA and RNA by intercalation or electrostatic attractions respectively. When bound to DNA, it is very similar spectrally to fluorescein, with an excitation maximum at 502 nm and an emission maximum at 525 nm (green). When it associates with RNA, the excitation maximum shifts to 460 nm (blue) and the emission maximum shifts to 650 nm (red). Acridine orange will also enter acidic compartments such as lysosomes where it becomes protonated and sequestered. Within these low pH vesicles the dye emits red fluorescence when excited by blue light. Thus, acridine orange can be used to visualize primary lysosomes and phagolysosomes that may include products of phagocytosis of apoptotic cells. The dye is often used in epifluorescence microscopy and flow cytometry. Acridine orange is an organic compound. It is used as a nucleic acid-selective fluorescent cationic dye useful for cell cycle determination. Being cell-permeable, it interacts with DNA and RNA by intercalation or electrostatic attractions respectively. When bound to DNA, it is very similar spectrally to fluorescein, with an excitation maximum at 502 nm and an emission maximum at 525 nm (green). When it associates with RNA, the excitation maximum shifts to 460 nm (blue) and the emission maximum shifts to 650 nm (red). Acridine orange will also enter acidic compartments such as lysosomes where it becomes protonated and sequestered. Within these low pH vesicles the dye emits red fluorescence when excited by blue light. Thus, acridine orange can be used to visualize primary lysosomes and phagolysosomes that may include products of phagocytosis of apoptotic cells. The dye is often used in epifluorescence microscopy and flow cytometry. At a low pH (3.5), when acridine orange is excited by blue light, it can differentially stain human cells green while staining prokaryotes bright orange for detection with a fluorescence microscope. This differential staining capability allows more rapid scanning of smears at a lower magnification (400×), than by Gram stain (1000×). Bright orange organisms are easily detected against a black to faint green background.