The Escherichia colik, b and phage P1 host specificity genes (hsp) were introduced into Salmonella typhimurium by means of E. coli Hfr × S. typhimurium F− crosses. The three systems were found to govern modification and restriction of phages P22 and L. The restriction coefficients were comparable to that of λ for the PI system and were lower (about 100) for the k and b systems. Phage grown on hspK+ and hspB+ recombinants was restricted by S. typhimurium independently of the restriction governed by the lt system. This observation suggested that S. typhimurium possesses a previously undetected hsp locus allelic to those of E. coli k and b.
ArberW., Wauters-WillemsD.1970; Host specificity of DNA produced by Eschericha coli. XII. The two restriction and modification systems of strain 15T−. Molecular and General Genetics 108:203–217
ColsonC., ColsonA. M.1967; Host specificity and fertility in Salmonella typhimurium LT7. Biochemical and Biophysical Research Communications 29:692–695
ColsonC., GloverS. W., SymondsN., StaceyK. A.1965; The location of the genes for host- controlled modification and restriction in Escherichia colik-12. Genetics 52:1043–1050
KondoE., MitsuhashiS.1966; Drug resistance of enteric bacteria. VI. Introduction of bacteriophage Pi CM into Salmonella typhi and formation of PidCM and F-CM elements. Journal of Bacteriology 91:1787–1794
WoodW. B.1966; Host specificity of DNA produced by Escherichia coli'. bacterial mutations affecting the restriction and modification of DNA. Journal of Molecular Biology 16:118–133