title: Microscale method for rapid isolation of covalently closed circular plasmid DNA from group N streptococci.
abstract: A method for rapid purification of plasmid DNA from lactic streptococci, utilizing microliter quantities of reagents, was developed by combination of a short lysozyme-mutanolysin cell wall digestion with a modification of the Escherichia coli plasmid isolation procedure of McMaster et al. (Anal. Biochem. 109:47-54, 1980). The preparations obtained were highly enriched for covalently closed circular DNA, and the method was applicable to plasmids of at least 40 megadaltons. Centrifugation in CsCl-ethidium bromide density gradients was not required.
mesh_terms: D004269:DNA, Bacterial / Q000302:isolation & purification*; D004270:DNA, Circular / Q000302:isolation & purification*; D004587:Electrophoresis, Agar Gel; D013294:Lactococcus lactis / Q000235:genetics* / Q000254:growth & development; D010957:Plasmids; D013291:Streptococcus / Q000235:genetics* / Q000254:growth & development
chemical_list: D004269:DNA, Bacterial; D004270:DNA, Circular