A METHOD FOR THE RE-ISOLATION OF AN AUTONOMOUSLY REPLICATING PLASMID FROM ASPERGILLUS TRANSFORMANTS

An autonomously replicating plasmid is expected to increase the freque ncy of Aspergillus transformation. To construct this type of plasmid, we developed a rapid method of re-isolating autonomously replicating p lasmids from Aspergillus transformants. Transformants grown in MM medi um under selective pressure for 1-2 days were converted to protoplasts with a cell wall lytic enzyme (e.g. Yatalase). The protoplasts were l ysed with phenol/chloroform followed by precipitation with ethanol. Th e total DNA was treated with RNaseA, re-precipitated with PEG, and the n used to transform E. coli. These re-isolated plasmids were mainly th e plasmid monomer.