Attempts to establish whether glucose is attached to the deoxyribonucleic acid of certain bacteriophages infecting Bacillus subtilis

Influence of bacteriophage PBS1 and phi W-14 deoxyribonucleic acids on homologous deoxyribonucleic acid uptake and transformation in competent Bacillus subtilis

Both bacteriophage PBS1 deoxyribonucleic acid (DNA) (in which all the thymine residues are replaced by uracil) and phage phiW-14 DNA [in which half the thymine residues are replaced by 5-(aminobutylaminomethyl)uracil or 5-putrescinylthymine] exhibit comparable competing abilities for uptake of homologous DNA in a Bacillus subtilis competent system. But, whereas PBS1 DNA leads to a decrease in transformation frequencies compatible with its competing ability for DNA uptake, phiW-14 DNA decreases transformation frequencies by a factor up to eightfold higher. The effect of phiW-14 DNA on transformation frequencies is visible even at a concentration level that does not decrease transforming DNA uptake. No such effect was observed with heterologous DNA containing presumably ionically bound putrescine. Low concentrations of phiW-14 DNA decreased the number of double (nonlinked) transformants more than single transformants. The influence on transformation was abolished when phiW-14 DNA was added 20 min after addition of transforming DNA, i.e., when the recombination process was terminated. The putrescine-containing DNA also decreased retention of trichloroacetic acid-precipitable radioactivity of homologous DNA taken up. We conclude that phiW-14 DNA inhibits some intracellular process(es) at the level of recombination. In addition, there is evidence that phiW-14 DNA, but not heterologous DNA with ionically bound putrescine, binds also to site(s) on the cell surface other than receptors for homologous DNA.

Bacteriophages of Bacillus subtilis

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New deoxyribonucleic acid polymerase induced by Bacillus subtilis bacteriophage PBS2

The deoxyribonucleic acid (DNA) of Bacillus subtilis phage PBS2 has been confirmed to contain uracil instead of thymine. PBS2 phage infection of wild-type cells or DNA polymerase-deficient cells results in an increase in the specific activity of DNA polymerase. This induction of DNA polymerase activity is prevented by actinomycin D and chloramphenicol. In contrast to the major B. subtilis DNA polymerase, which prefers deoxythymidine triphosphate (dTTP) to deoxyuridine triphosphate (dUTP), the DNA polymerase in crude extracts of PBS2-infected cells is equally active whether dTTP or dUTP is employed. This phage-induced polymerase may be responsible for the synthesis of uracil-containing DNA during PBS2 phage infection.