| 主权项 |
1. A method for isolating recombinant marine cyanobacteria containing a recombinant form of a high copy number endogenous plasmid and lacking the wild-type form of said high copy number endogenous plasmid, said recombinant form of said high copy number endogenous plasmid comprising a wild-type high copy number endogenous plasmid backbone and an exogenous polynucleotide sequence insert, said exogenous polynucleotide sequence insert comprising a selective marker, said method comprising:
a) culturing a recombinant marine cyanobacteria comprising said recombinant form of said high copy number endogenous plasmid on low salt media comprising concentrations of a selective agent, b) analyzing plasmid DNA from colonies cultured on a medium of step a) for the presence of said recombinant form of said high copy number endogenous plasmid and for the absence of said wild-type high copy number endogenous plasmid, and c) isolating recombinant marine cyanobacteria from step b) that contain copies of said recombinant form of said high copy number endogenous plasmid and do not contain said wild-type high copy number endogenous plasmid. |
