Mitochondrial DNA from Oenothera berteriana: PURIFICATION AND PROPERTIES.
Mitochondrial DNA (mt-DNA) from Oenothera berteriana tissue culture cells was isolated and characterized with respect to buoyant density in CsCl, melting point, contour length, and restriction fragments.Because of the rather long purification procedure very few molecules retained their circularity. Only one distinct size class of molecules with a length of 100 kilobases was found. Restriction fragments were obtained with the enzymes, restrictionendonuclease I from Serratia marcescens, restrictionendonuclease III from Haemophilus influenzae, restrictionendonuclease I from Bacillus amyloliquefaciens H, and restrictionendonuclease I from Escherichia coli (Bohnert 1977 Exp Cell Res 106: 426-430); the added lengths of these fragments amounted to 180 to 190 kilobases. As in other higher plants, an intermolecular heterogeneity has to be postulated to explain the large number of restriction fragments. Unique to the mt-DNA from Oenothera berteriana, as compared to other higher plants, is the unusual high guanosine + cytosine content with 51% as determined by the buoyant density in CsCl of 1.710 grams/cubic centimeter and the melting point of 90 C.
Brennicke
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Institut für Biologie I, Universität Tübingen, Auf der Morgenstelle 1, D-7400 Tübingen, Federal Republic of Germany.