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The blue-green alga agmenellum quadruplicatum contains covalently closed DNA circles
Cell
|December 1, 1976
Abstract:
This paper reports the first direct visualization of covalently closed, circular DNA from a blue-green alga. Agmenellum quadruplicatum lysates, fractionated on CsCl-ethidium bromide density gradients, yield a minor band of covalently closed DNA circles which we have analyzed by electron microscopy and agarose gel electrophoresis. The DNA consists of a number of a discrete classes of DNA circles ranging in molecular weight from 3 X 10(6) daltons to 65-80 X 10(6) daltons. The function of these circles is at present entirely unknown.
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