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W Arber

Publications and source records attributed to W Arber.

105 records · Page 6Linked to original sources
PubMed1969

Host specificity of DNA produced by Escherichia coli. XI. In vitro modification of phage fd replicative form.

An enzymatic activity, having the properties expected of a B-specific host-controlled modification enzyme, has been purified from an extract of Escherichia coli strain B. This activity renders the unmodified replicative form of phage fd resistant to B-specific restriction and is only present in strains carrying intact genes for type B modification. In phosphate buffer, the enzyme acts optimally at pH 6 and is dependent upon a single cofactor, S-adenosylmethionine.

Chromatography↗
PubMedDate not supplied

Mechanisms in microbial evolution.

Molecular genetic studies with prokaryotic microorganisms reveal that many different molecular processes contribute to the formation of spontaneous mutations. Besides infidelities in DNA replication and the consequences of environmental mutagens, enzyme-mediated DNA rearrangements bring about important, evolutionarily relevant alterations in the genetic information. Particular attention is given in this article to site-specific recombination at secondary crossover sites and to the transposition of mobile genetic elements with relaxed target specificity. Besides these diverse processes of genomic mutation the acquisition of genetic information from other organisms plays an uncontested role in microbial evolution. Enzymes and organelles mediating any of these mutational processes can be looked at as biological functions acting at the level of populations for the needs of biological evolution, rather than to fulfill the needs of individual living organisms.

Bacteria↗