Biomedical subjects

J Inselburg

Publications and source records attributed to J Inselburg.

64 records · Page 4Linked to original sources

PubMed1972

Electron microscopic studies of replicating and catenated colicin factor E1 DNA isolated from minicells (DNA replication).

Replicating and catenated DNA molecules of colicin factor E1 that were isolated from minicells were observed by electron microscopy. Two new replicating structures that have been found include: molecules that contain two untwisted replicated branches of the same length and a twisted unreplicated branch, and a twisted circular molecule with a long tail. Other molecular forms identified include circular dimers, three types of catenated dimers (open-open, open-twisted, and twisted-twisted), catenated dimers in which one of the linked molecules is replicating, catenated trimers, and a tetamer.

Centrifugation, Density Gradient↗

PubMed1971

Integration and excision of phi-80pt prophage in Escherichia coli. I. Replacement of tryptophan genes of phi-80pt with the host alleles through the lysogenic process.

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Alleles↗

PubMed1971

Isolation of catenated and replicating DNA molecules of colicin factor E1 from minicells.

Various catenated and replicating molecules of colicin E1 isolated from minicells have been identified in regions of neutral sucrose density gradients or cesium chloride-ethidium bromide density gradients. These colicin molecules have been found in those regions of the gradient where pulse-labeled DNA accumulates.

Cells, Cultured↗

PubMed1971

R factor deoxyribonucleic acid in chromosomeless progeny of Escherichia coli.

The deoxyribonucleic acid (DNA) of resistance (R) factor 222 carried by Escherichia coli strain P678-54 was found in the normally chromosomeless progeny (minicells) of that strain. The entry of the R222 DNA into minicells appears to be via segregation at the time of their formation from normal cells. The R222 DNA can replicate in minicells although the extent of its replication appears to be limited. An analysis of the R222 DNA structure indicates that it exists in minicells as double-stranded linear, open circular, and twisted circular monomers (molecular weight, about 6.2 x 10(7) daltons). The monomers visualized by electron microscopy are 31.0 +/- 0.5 mum in length. An examination of the effect of acridine orange on the replication of R222 and colicin E1 DNA indicates the dye intereferes with plasmid DNA replication.

Acridines↗

PubMed1970

Replicating DNA: structure of colicin factor E1.

Replicating circular molecules of colicin factor E1 have been isolated from minicells produced by a colicinogenic derivative of Escherichia coli P678-54. The replicating structures observed in electron micrographs are circular molecules with two branched points. Several structures found among the replicating molecules are interpretable as replicating rolling circles.

Colicins↗

PubMed1970

Segregation into and replication of plasmid deoxyribonucleic acid in chromosomeless segregants of Escherichia coli.

The progeny cells of Escherichia coli strain P678-54, which normally do not contain deoxyribonucleic acid (DNA), were found to carry DNA when the parental cell carried colicin factor E1 (Col E1). The DNA found in the normally DNA-less segregants was shown to be Col E1 DNA, which is present primarily as a covalently closed circular molecule that can undergo more than one complete cycle of replication.

Centrifugation, Density Gradient↗

PubMed1968