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Excitation under the scanning electron microscope of DNA‐associated fluorescence from chicken erythrocyte nuclei, polytene chromosomes and adenovirus 2 virions
Author(s) -
Hough Paul V. C.,
McKinney Wayne R.
Publication year - 1981
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1981.tb01259.x
Subject(s) - polytene chromosome , microscopy , electron microscope , fluorescence microscope , fluorescence , dna , scanning electron microscope , biophysics , microscope , biology , chemistry , optics , microbiology and biotechnology , physics , chromosome , genetics , gene
Biological structures not seen by conventional light microscopy, such as longitudinal striations in polytene chromosomes, and, at the limit of sensitivity, virions of adenovirus 2, have been detected via DNA‐associated fluorescence excited under the scanning electron microscope. The maximum sensitivity realized, about 1 detected photon per 700 base pairs, falls short by about an order of magnitude of that required to achieve, in unreplicated specimens, the 2 nm intrinsic resolution of the method. A combination of D 2 O‐H 2 O substitution with freeze‐drying provides the best unquenching procedure found for in situ DNA. DNA‐associated fluorescence for light microscopy can be created by moderate exposure of the specimen in the electron microscope.