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R & M

  • Rudolf Hausmann
Chapter

Abstract

At the apogee of the early phage school, Luria & Human (1952) made a remarkable observation: phage T2, grown on a strain of coli B/4, was unable to go through a second growth cycle on the same host (as shown much later, the critical step lay in traversing the host cell membrane). Only a special strain of Shigella dysenteriae would permit growth of these phages; however, the descendants from the growth cycle in Shigella could grow again on B/4. It looked as though the phages coming out of B/4 could remember their last host; they were somehow modified by it, marked. This example brought to light the phenomenon of host-dependent modification (M), which cried out for an explanation. This observation described by Luria & Human turned out to be quite a special case, based on the incapacity of the strain E. coli B/4 to synthesize uridine-diphosphoglucose (UDPG), a compound necessary for the typical glucosylation of T2 DNA. The glucosylation of T2 DNA was a prerequisite for its penetrating through the cell membrane of E. coli; this, because a DNAase located there (absent in Shigella), broke down the unglucosylated T2 DNA. The phage T2 was thus “restricted” in its growth; in other words, it was subjected to the phenomenon of restriction (R) by this particular strain of coli. This peculiar occurrence was — and still remains — a typical instance of the matters preoccupying researchers confined in their academic ivory towers. Many further restricting and modifying hosts, as well as restricted and modified phages, were discovered; one special case was scrutinized by Werner Arber and his co-workers at the University of Geneva (see, for instance, Arber, 1965a, 1968; Arber & Linn, 1969):

Keywords

Haemophilus Influenzae Host Cell Membrane Shigella Dysenteriae Phage Titre Single Restriction Enzyme 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media Dordrecht 2002

Authors and Affiliations

  • Rudolf Hausmann
    • 1
  1. 1.Institut für Biologie IIIUniversity of FreiburgGermany

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