Expression of a new porin 'OmpE' by strains of Salmonella enteritidis

Abstract Strains of Salmonella enteritidis expressed a novel porin with a subunit size of 35.5 kDa as shown by SDS-PAGE. This protein was expressed as a major outer membrane protein (MOMP) when grown on nutrient agar, McConkey agar or blood agar, or in Tris-succinate medium; but was only produced in trace amounts when strains were grown in nutrient broth. This OMP was produced by all strains of S. enteritidis examined, regardless of phage type, and expression was not related to the possession of a 38-MDa mouse-virulence plasmid or the ability of strains to make long-chain lipopolysaccharide. This new porin has been tentatively called OmpE.