| 摘要 |
PURPOSE:To effectively utilize a plasmid as a vector for improving the existing gene, by preparing a plasmid pEC3 or pEC8 having 5.8kb or 8kb molecular weight and a specific restriction enzyme cleavage map. CONSTITUTION:A plasmid obtained by decomposing a cell wall of a culture of a plant parasitic bacterium belonging to the genus Erwinia with lysozyme, etc., subjecting the resultant culture to bacteriolysis, deproteinizing the bacteriolytic product using alkali treatment together, precipitating the resultant DNA with an alcohol, e.g. propanol, purifying the precipitate with CsCl to give a plasmid (pEC3) having 5.8kb molecular weight and a restriction enzyme cleavage map shown in Fig. 1 and plasmid (pEC8) having 8kb and a restriction enzyme cleavage map shown in Fig. 2. Both plasmid (pEC3) and plasmid (pEC8) are cyclic double-stranded DNA. |
