Infectious Nucleic Acids of Escherichia coli Bacteriophages
Tóm tắt
Various strains of
Ø× 174 DNA saturation experiments indicated that 0.05–1% of the lysozyme spheroplasts were competent. Between 12 and 20 minutes after the addition of a non‐saturating level of 32P‐labelled Ø× 174 DNA to such competent cell populations at 37°, 10–20% of the label was adsorbed. Noncompetent cell populations adsorbed no more than 4% of the added label. Prolonging the DNA adsorption time did not give a higher efficiency of DNA infection, because the cells began losing competence through a temperature‐dependent process.
More than 90% of the infectious Ø× 174 DNA centers reamined sensitive to DNAase during the first 20 minutes in DNA adsorption medium. Plating Ø× 174 DNA and M 12 RNA‐infected cells on eosin methylene blue agar during this period prevented the formation of phage, whereas the plaque‐forming ability of the mature phage was not inhibited. These observations may suggest an unusual permeability of the competent cells.
Inhibitors of phage RNA infection were removed by washing the competent cells. DNAase pretreatment of the spheroplasts increased their competence for infectious M 12 phage RNA.
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Tài liệu tham khảo
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