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

H Chart1, J A Frost, B Rowe

  • 1Laboratory of Enteric Pathogens, Central Public Health Laboratory, London, UK.

FEMS Microbiology Letters
|May 15, 1993
PubMed

Insights

Salmonella enteritidis produces a novel outer membrane protein (OMP), tentatively named OmpE. This porin is a major outer membrane protein under specific growth conditions, regardless of phage type or virulence factors.

Area of Science:

  • Microbiology
  • Bacteriology
  • Protein Chemistry

Background:

  • Salmonella enteritidis is a significant bacterial pathogen.
  • Outer membrane proteins (OMPs) play crucial roles in bacterial physiology and host-pathogen interactions.
  • Understanding novel OMPs can provide insights into bacterial virulence and potential targets for intervention.

Purpose of the Study:

  • To identify and characterize a novel porin expressed by Salmonella enteritidis.
  • To investigate the expression patterns of this new porin under different growth conditions.
  • To determine if the expression of this porin is associated with specific S. enteritidis characteristics like phage type or virulence plasmids.

Main Methods:

  • Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to determine protein size.
  • Culturing S. enteritidis strains on various agar media and in different liquid media.
  • Analysis of OMP expression levels under varied growth conditions.
  • Correlation analysis with phage typing and presence of virulence plasmids.

Main Results:

  • A novel porin with a subunit size of 35.5 kDa was identified in S. enteritidis using SDS-PAGE.
  • This porin was expressed as a major outer membrane protein (MOMP) on nutrient agar, McConkey agar, blood agar, and in Tris-succinate medium.
  • Trace amounts of the porin were produced in nutrient broth.
  • The porin was expressed by all examined S. enteritidis strains, irrespective of phage type.
  • Expression was independent of a 38-MDa mouse-virulence plasmid and long-chain lipopolysaccharide production.

Conclusions:

  • A new porin, tentatively named OmpE, is consistently expressed by Salmonella enteritidis.
  • OmpE expression is significantly influenced by growth medium composition.
  • The presence and expression of OmpE are not linked to common virulence markers in S. enteritidis.

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