Release of transforming plasmid DNA from actively growing genetically engineered Escherichia coli.
We studied the transforming ability of the extracellular plasmid DNA released from a genetically engineered Escherichia coli pEGFP and the culturing conditions for the release of transforming DNA. The transforming ability was evaluated by transformation of competent cells with filtrates of E. coli pEGFP cultures. The number of transformants increased with time when E. coli pEGFP cells grew exponentially in rich medium, but not in stationary phase or when inoculated in freshwater. These results suggested that crude extracellular plasmid DNA had transforming ability and this transforming DNA was mainly released by actively growing bacteria.
Ishii
Nobuyoshi
N
Environmental and Toxicological Sciences Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan. nobu@nirs.go.jp
Matsui
Kazuaki
K
Fuma
Shoichi
S
Takeda
Hiroshi
H
Kawabata
Zen'ichiro
Z
D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005453:Fluorescence; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism*; D014169:Transformation, Bacterial
D004269:DNA, Bacterial; D049452:Green Fluorescent Proteins