Quantitative analysis of chromosomal and plasmid DNA during the growth of spheroplasts of Escherichia coli

[摘要] We generated spheroplasts from Escherichia coli carrying a broad-host-range plasmid. In the presence of penicillin, the spheroplasts did not divide but grew and enlarged in marine broth, whereas, in the absence of penicillin, they elongated. We quantified cellular DNA at different time points by using real-time quantitative PCR. Both chromosomal and plasmid DNA had replicated during spheroplast growth not only in the absence but also in the presence of penicillin. Thus, plasmid DNA and chromosomal DNA replication might be regulated synchronously during the growth of spheroplasts.

[学科分类] 微生物学和免疫学

[关键词] chromosome replication;Escherichia coli;giant spheroplasts;plasmid replication;quantitative PCR