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|Section2= |Section7= }} 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 and become protonated and sequestered. In these low pH conditions, the dye will emit orange light when excited by blue light. Thus, acridine orange can be used to identify engulfed apoptotic cells, because it will fluoresce upon engulfment. The dye is often used in epifluorescence microscopy. ==Optical properties== 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 (400x), than by Gram stain (1000x). Bright orange organisms are easily detected against a black to faint green background. When an acridine orange binds with DNA, it exhibits an excitation maximum at 502 nm (cyan) and an emission maximum at 525 nm (green). When it binds with RNA, the excitation maximum is located at 460 nm (blue) and the emission maximum is located at 650 nm (red). This is all due to the electrostatic interactions occurring when the acridine molecule intercalates between the nucleic acid base pairs. Acridine orange binding with the nucleic acid occurs in both living and dead bacteria, also other microorganisms. Acridine orange is useful for enumerating the microbes in a sample. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Acridine orange」の詳細全文を読む スポンサード リンク
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