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Biomedical subjects

E James

Publications and source records attributed to E James.

At least 109 records · Page 6Linked to original sources
PubMed1977

Evolutionary drift of the argF and argl genes. Coding for isoenzyme forms of ornithine transcarbamylase in E. coli K12.

Considerable genetic drift has occurred during the evolution of the two genes, argF and argl, which individually code for isoenzyme forms of ornithine transcarbamylase in E. coli K12. The use of the experimental protocol described in this work established that between 25-40% of the base pairs in the genes argF and argl have changed since they diverged from a hypothetical ancestral gene. The extent of divergence of the genes was determined by mRNA-DNA hybridization utilizing arginine transducing DNA as a hybridization probe and mRNA prepared in vivo from appropriate bacterial strains and with mRNA synthesized in vitro using template DNA isolated from the specialized transducing phages gammacI857dargl and phi80dargF.

Coliphages↗
PubMed1977

In vitro transcription of the Escherichia coli K-12 argA, argE, and argCBH operons.

Deoxyribonucleic acid isolated from argA and argECBH transducing phages was utilized to study the in vitro synthesis of argA, argE, and argCBH messenger ribonucleic acid. The specific regulation of these operons by the arginine holorepressor was demonstrated, providing evidence that the majority, if not all, of the control of these operons is exercised at the transcriptional level. Data are presented which indicate that the arginine holorepressor functions by binding to the operator region and concomitantly prevents the binding of ribonucleic acid polymerase to the corresponding promoter region.

Arginine↗
PubMed1977

Metabolism of arginine-specific messenger ribonucleic acid in Escherichia coli K-12.

Ribonucleic acid-deoxyribonucleic acid (RNA-DNA) hybridization was employed for the determination of the level of messenger RNA (mRNA) transcribed from seven of the nine genes of the arginine regulon of Escherichia coli K-12. The quantity of RNA complexing with each of the separated DNA strands of the argA, argF, argE, and argCBH operons carried on specialized transducing phages was measured. The derepressed:repressed ratio of mRNA formed in vivo was found to vary between about 3 and 4 when measured by hybridization to DNA isolated from specialized transducing phages carrying the argA, argE, argCBH, argF, and argI operons.

Arginine↗
PubMed1976

Isolation and characterization of the specialized transducing bacteriophages phi80dargF and lambdah80cI857 dargF: specific cleavage of arginine transducing deoxyribonucleic acid by the endonucleases EcoRI and SmaR.

The directed transposition of argF to the tonB locus of the Escherichia coli chromosome and the subsequent isolation of the specialized transducing phage phi80dargF is described. The structure of this phage has been has been determined. A hybrid lambdah80cI857dargF phage has been constructed. Deoxyribonucleic acid isolated from these and their parent bacteriophages has been specifically cleaved by the endonucleases EcoRI and SmaR; the unique deoxyribonucleic acid fragments thus obtained have been resolved and analyzed by electrophoresis in agarose gel.

Arginine↗
PubMed1975

Resolution of the DNA strands of the specialized transducing bacteriophage lambda-h80C 1-857 dargF.

The DNA strands of lambdoid phages with deletions or substitutions of the guanine plus cytosine-rich region in the left arm are not resolvable by complexing with poly UG followed by centrifugation in CsCl. This work describes a completely general procedure for the strand resolution of these phages by hybridization with fragments of separated strands of the parent phage. In particular, resolution of the DNA strands of the specialized transducing phage lambda-h80C1-857dargF is described, and evidence is presented which indicates that argF is transcribed from the r strand.

Arginine↗