Adsorption of phage λ to Salmonella typhimurium lamB + requires the presence of lipopolysaccharide in the outer membrane

Two S. typhimurium strains TA1534 (rfa+) and TA1538 (rfaE) were transformed with the lamB expression plasmid pAMH70. Transposition events with λplacMu55 hybrid phage were successful only with TA1534/pAMH70 strain. Using SDS-PAGE, the LamB protein was present in the total cell proteins but not in the outer membrane proteins of the TA1538/pAMH70 strain. The LamB protein must linked to the LPS of the outer membrane to allow adsorption of λ phage in S. typhimurium.