Degradation of
            <i>Escherichia coli</i>
            B Deoxyribonucleic Acid After Infection with Deoxyribonucleic Acid-Defective Amber Mutants of Bacteriophage T7

Sadowski, Paul D.; Kerr, Carol

doi:10.1128/jvi.6.2.149-155.1970

Cited by 87 publications

(25 citation statements)

References 25 publications

(27 reference statements)

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“…The majority of this degradation is the result of T4 DNase activity (5,41). Similar degradation of host cell DNA by phage-induced enzymes has been observed in other bacteriophage systems (9,13,32,36). The antimicrobial agent colicin E2 also induces the rapid degradation of E. coli DNA to fragments of about 106 daltons (18,29).…”

Section: Resultsmentioning

confidence: 72%

Regulated breakdown of Escherichia coli deoxyribonucleic acid during intraperiplasmic growth of Bdellovibrio bacteriovorus 109J

Rosson¹,

Rittenberg²

1979

J Bacteriol

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During growth of Bdellovibrio bacteriovorus on [2-"C]deoxythymidine-labeled Escherichia coli, approximately 30% of the radioactivity was released to the culture fluid as nucleoside monophosphates and free bases; the remainder was incorporated by the bdellovibrio. By 60 min after bdellovibrio attack, when only 10% of the E. coli deoxyribonucleic acid (DNA) had been solubilized, the substrate cell DNA was degraded to 5 x 105-dalton fragments retained within the bdelloplast. Kinetic studies showed these fragments were formed as the result of sequential accumulation of singleand then double-strand cuts. DNA fragments between 2 x 103 and 5 x 105 daltons were never observed. Chloramphenicol, added at various times after initiation of bdellovibrio intraperiplasmic growth on normal or on heated E. coli, which have inactivated deoxyribonucleases, inhibited further breakdown and solubilization of substrate cell DNA. Analysis of these intraperiplasmic culture deoxyribonuclease activities showed that bdellovibrio deoxyribonucleases are synthesized while E. coli nucleases are inactivated. It is concluded that continuous and sequential synthesis of bdellovibrio deoxyribonucleases of apparently differing specificities is necessary for complete breakdown and solubilization of substrate cell DNA, and that substrate cell deoxyribonucleases are not involved in any significant way in the degradation process. MATERIALS AND METHODSGrowth and harvesting of cells. B. bacteriovorus 109J was the experimental organism, and normal or heated [2-'4C]deoxythymidine-labeled E. coli ML35 620 on July 31, 2020 by guest

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Section: Resultsmentioning

confidence: 72%

Regulated breakdown of Escherichia coli deoxyribonucleic acid during intraperiplasmic growth of Bdellovibrio bacteriovorus 109J

Rosson¹,

Rittenberg²

1979

J Bacteriol

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“…They concluded that there are attachment points in E. coli. A similar number can be estimated from the measurement of the size of E. coli DNA released during infection with phage T7 mutants (34). Ivarie and Pene (18) estimated that the number of at-tachment points in Bacillus subtilis is 70 to 90.…”

mentioning

confidence: 88%

Effect of Rifampin on the Structure and Membrane Attachment of the Nucleoid of Escherichia coli

1973

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Deoxyribonucleic acid (DNA) of Escherichia coli was found to be attached to the cell membrane at about 20 points. This was determined by fractionation of X-irradiated cells with the M band (magnesium-Sarkosyl crystals) technique. The number of attachment points was computed from the relationship between the amount of DNA in M bands and the number of double-strand breaks introduced by the X-ray treatment. The number of attachment points was decreased fourfold by treatment of cells with rifampin. This effect was apparently due to the action of the drug on ribonucleic acid (RNA) polymerase since the drug did not affect a mutant whose RNA polymerase is resistant to rifampin. This suggests that there may be two classes of attachment points of DNA on the membrane, some of which are removed by rifampin treatment and some which are not. Rifampin treatment also resulted in the uncondensing of isolated nucleoids and in an axial appearance of the nucleoids in ultrathin sections. The results suggest that RNA polymerase plays a role, direct or indirect, in maintaining the structure of the bacterial nucleoid and in some of its attachment to the membrane.

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“…prelabel is lost as acid-soluble material in such an experiment (18), this label serves as a useful indication of the behavior of bulk intracellular DNA. The 3H label added at 7 min after infection is a marker primarily for phage sequences.…”

Section: Resultsmentioning

confidence: 99%

Purification and structures of recombining and replicating bacteriophage T7 DNA

Langman¹,

Paetkau²

1978

J Virol

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During the infection of Escherichia coli by bacteriophage T7, there is a gradual conversion of host DNA to T7 DNA. Recombination and replication occur during this time. We have devised a new way of examining the physical structures of the intermediates of these processes. It is based on the observation that there are no sites in T7 DNA susceptible to cleavage by the restriction endonuclease EcoRI. E. coli DNA, on the other hand, is susceptible to degradation by EcoRI. Thus, phage and host DNA can be separated by sucrose gradient centrifugation after treatment with EcoRI. Concatemeric T7 DNA contains a high proportion of branched, gapped, and whiskered structures. These appear to be intermediates of replication and recombination. This approach also monitors the conversion process from host to T7 DNA.

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Degradation of Escherichia coli B Deoxyribonucleic Acid After Infection with Deoxyribonucleic Acid-Defective Amber Mutants of Bacteriophage T7

Cited by 87 publications

References 25 publications

Regulated breakdown of Escherichia coli deoxyribonucleic acid during intraperiplasmic growth of Bdellovibrio bacteriovorus 109J

Regulated breakdown of Escherichia coli deoxyribonucleic acid during intraperiplasmic growth of Bdellovibrio bacteriovorus 109J

Effect of Rifampin on the Structure and Membrane Attachment of the Nucleoid of Escherichia coli

Purification and structures of recombining and replicating bacteriophage T7 DNA

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