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Biomedical subjects

W Presber

Publications and source records attributed to W Presber.

At least 73 records · Page 4Linked to original sources
PubMed1977

Host-dependent modification of bacteriophage T7 and SAMase-negative T3 derivatives affecting their adsorption ability.

When passaging phage T7 and SAMase-negative T3 mutants between E. coli strains with identical (EcoB) or without (EcoO) DNA host specificity, phenotypically a host-controlled modification and restriction is observed. This phenomenon is not due to "classical" modification and restriction of the bacteriophage DNA but depends on the reversibly altered adsorption capacity of the phages on the different host strains.

Adenosylmethionine Decarboxylase↗
PubMed1977

Different restriction of bacteriophages T3 and T7 by P1-lysogenic cells and the role of the T3-coded SAMase.

The intracellular growth of the phages T3 and T7 is restricted in the presence of the Escherichia coli prophage P1. Phage T3 has a higher ability to express its genome and to damage the host cell than T7. This partial protection of T3 against P1 restriction is due to the T3-coded SAMase, an enzyme which degrades S-adenosylmethionine, the cofactor of the P1 restriction endonuclease. Since we did not observe DNA cleavage in vivo, we conclude that the in vivo action of the P1 nuclease is limited to a SAM-dependent repressor-like binding to T3 and T7 DNA, while further reactions with the DNA (modification vs cleavage) are blocked.

Coliphages↗
PubMed1975

Biological functions of the bacteriophage T3 SAMase gene.

Certain differences between phage T3 on the one hand and T3sam- and T7 on the other hand indicate that the T3-coded SAMase function is responsible (i) for the development of the pseudolysogenic state by preventing T3 DNA methylation, and (ii) for the partial protection of the phage DNA against restriction by the P system.

Coliphages↗