The host specificity system inEscherichia coli SK

1976 ◽  
Vol 13 (2) ◽  
pp. 79-87 ◽  
Author(s):  
I. I. Nikolskaya ◽  
N. G. Lopatina ◽  
N. M. Chaplygina ◽  
S. S. Debov
Keyword(s):  
Host Specificity ◽  
Inescherichia Coli ◽  
Specificity System

scholarly journals Functional analysis of host-specificity mutants inEscherichia coli

1970 ◽  
Vol 15 (2) ◽  
pp. 237-250 ◽  
Author(s):  
S. W. Glover
Keyword(s):  
Functional Analysis ◽  
Host Specificity ◽  
Restriction Enzyme ◽  
Molecular Level ◽  
Inescherichia Coli ◽  
Strain Specificity ◽  
Specific Modification ◽  
Specific Restriction ◽  
Modification Enzyme

SUMMARYEvidence from a functional analysis of host-specificity mutants in merodiploids is presented which supports the suggestion that three genes,hss, hsrandhsm, are necessary for the expression of host-controlled restriction and modification. The host-specificity phenotype expressed by the merodiploids provides evidence that at least two genes,hssandhsr, are concerned in the expression of host-specific restriction of DNA and one of these genes,hss, is responsible for the strain specificity of the restriction enzyme. A class of modification-deficient mutants isolated from restriction-deficient, modification-proficient mutants, was also tested for complementation in merodiploids and the phenotype of these merodiploids provides evidence that at least two genes,hssandhsm, are concerned in the expression of host-specific modification of DNA and one of these genes,hss, is responsible for the strain specificity of the modification enzyme. How these three genes function at the molecular level is discussed in terms of models based on the interaction of subunits to form oligomeric enzymes.

Identification of a host specificity system inShigella

1980 ◽  
Vol 90 (3) ◽  
pp. 1245-1247 ◽  
Author(s):  
M. I. Tediashvili ◽  
T. M. Uporova ◽  
I. I. Nikol'skaya ◽  
S. S. Debov
Keyword(s):  
Host Specificity ◽  
Specificity System

Structures and mechanisms of DNA restriction and modification enzymes

1979 ◽  
Vol 12 (3) ◽  
pp. 315-369 ◽  
Author(s):  
Paul Modrich
Keyword(s):  
Host Cell ◽  
Host Specificity ◽  
Bacterial Cell ◽  
Genetic Information ◽  
Molecular Basis ◽  
Cell Types ◽  
Bacteriophage Λ ◽  
Viral Dna ◽  
Dna Restriction ◽  
Specificity System

DNA restriction and modification enzymes are responsible for the hostspecific barriers to interstrain and interspecies transfer of genetic information that have been observed in a variety of bacterial cell types. Although the phenomenon of host specificity was initially observed in the early 1950s (Luria & Human, 1952; Bertani & Weigle, 1953), it was nearly a decade later that Arber and his colleagues accurately predicted the molecular basis of the phenomenon. Their experiments with bacteriophage λ demonstrated that a given host-specificity system imparts a specific modification to the viral DNA, and further, that restriction of DNA lacking the appropriate modification is s consquence of nucleolytic hydrolysis upon entry into the host cell (Arber & Dussoix, 1962; Dussoix & Arber, 1962; Arber, Hattman & Dussoix, 1963).

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