Analysis of Host Range Restriction in
            <i>Escherichia coli</i>
            Treated with Toluene

Fleischman, Roger A.; Richardson, Charles C.

doi:10.1073/pnas.68.10.2527

“…Thus, phage infection evidently does not abolish restriction in this strain. (ii) As shown by Fleischman and Richardson (7), activity of the restriction system can be observed in toluenized cells of E. coli K strains. The substitution of 5-hydroxymethyl dCTP for dCTP in this system abolishes observed DNA synthesis, presumably because the restriction activity degrades hydroxymethyl cytosine-containing DNA as fast as it is synthesized.…”

Section: Minutes After Nfectionmentioning

confidence: 76%

Bacteriophage-host interaction and restriction of nonglucosylated T6

Hewlett¹,

Mathews²

1975

J Virol

7

0

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Nonglucosylated T6 phage (T6gtaml6am3O, hereafter called T6agt-) were found to have two structural anomalies when compared with wild-type T6. The DNA of T6agtphage contains single-strand interruptions. These can be seen both during infection, in the pool of replicating DNA, and in DNA extracted from purified phage. In addition, the sodium dodecyl sulfate-polyacrylamide gel pattern of T6agtphage structural proteins reveals a protein band not found in T6. The altered protein has a mobility slightly faster than that of the major head protein, and it is not removed by osmotic shock. The restriction activity of Escherichia coli B directed against T6agtphage is abolished by preinfection of the cells for 4 min with T4 imm2. The shut-off of restriction is observed either by the rescue of superinfecting T6agtor by the failure to detect degradation of incoming T6agt-DNA. This effect is resistant to rifampin and chloramphenicol.

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“…A few years later, Charles Thomas joined the department and brought with him a breath of fresh air. Later, in 1971, Roger Fleischman, an MD-PhD student, showed that E. coli cells made permeable with toluene could incorporate hydroxymethylcytosine into their DNA, an event that halted DNA synthesis in strains that restricted phage with nonglycosylated DNA (22). Roger and Judy Campbell, also a graduate student, reproduced this phenomenon in vitro, but the activity proved elusive (23).…”

Section: Glycosylated Bacteriophage T4 Dnamentioning

confidence: 99%

Untitled

2015

Annu. Rev. Biochem.

3

0

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I spent my childhood and adolescence in North and South Carolina, attended Duke University, and then entered Duke Medical School. One year in the laboratory of George Schwert in the biochemistry department kindled my interest in biochemistry. After one year of residency on the medical service of Duke Hospital, chaired by Eugene Stead, I joined the group of Arthur Kornberg at Stanford Medical School as a postdoctoral fellow. Two years later I accepted a faculty position at Harvard Medical School, where I remain today. During these 50 years, together with an outstanding group of students, postdoctoral fellows, and collaborators, I have pursued studies on DNA replication. I have experienced the excitement of discovering a number of important enzymes in DNA replication that, in turn, triggered an interest in the dynamics of a replisome. My associations with industry have been stimulating and fostered new friendships. I could not have chosen a better career.

show abstract

“…A few years later, Charles Thomas joined the department and brought with him a breath of fresh air. Later, in 1971, Roger Fleischman, an MD-PhD student, showed that E. coli cells made permeable with toluene could incorporate hydroxymethylcytosine into their DNA, an event that halted DNA synthesis in strains that restricted phage with nonglycosylated DNA (22). Roger and Judy Campbell, also a graduate student, reproduced this phenomenon in vitro, but the activity proved elusive (23).…”

Section: Glycosylated Bacteriophage T4 Dnamentioning

confidence: 99%