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Published on: February 5, 2015
Influence of the culture medium on the expression of surface polypeptides of Yersinia enterocolitica
A Sampedro1, M Jimenez-Valera, A Ruiz-Bravo
1Departamento de Microbiología, Facultad de Farmacia, Universidad de Granada, España.
Abstract:
Three polypeptides (200, 46, and 25 kDal) encoded by the virulence plasmid were detected by SDS-PAGE in the outer membrane of Yersinia enterocolitica 09 grown at 37 degrees C in brain-heart infusion medium. Bacteria grown at the same temperature in the tissue culture medium RPMI 1640 expressed five additional polypeptides (170, 135, 118, 100, and 98 kDal), but the 25-kDal band was not seen. The protein profile in RPMI 1640 resembles the expression pattern displayed by yersiniae when grown in vivo. The immunoblot of total membrane proteins of bacteria grown in brain-heart infusion medium revealed eight plasmid-encoded polypeptides, four of which were also in the outer membrane preparations, including a 28-kDal polypeptide. These peptides do not coincide with known plasmid-encoded outer membrane proteins.
Insights
Yersinia enterocolitica outer membrane proteins differ based on growth medium. RPMI 1640 medium better mimics in vivo conditions, revealing more virulence plasmid-encoded proteins.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Yersinia enterocolitica is a human pathogen.
- Virulence factors are crucial for bacterial infection.
- Outer membrane proteins play key roles in bacterial-host interactions.
Purpose of the Study:
- To characterize the outer membrane proteins of Yersinia enterocolitica.
- To investigate the effect of different growth media on protein expression.
- To identify novel virulence plasmid-encoded outer membrane proteins.
Main Methods:
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for protein separation.
- Growth of Yersinia enterocolitica in brain-heart infusion medium and RPMI 1640 medium.
- Immunoblotting to detect plasmid-encoded polypeptides.
Main Results:
- Three virulence plasmid-encoded polypeptides (200, 46, 25 kDal) were identified in the outer membrane using brain-heart infusion medium.
- Growth in RPMI 1640 medium induced five additional polypeptides (170, 135, 118, 100, 98 kDal) and lost the 25-kDal band.
- The RPMI 1640 expression profile closely resembled in vivo conditions.
- Eight plasmid-encoded polypeptides were detected in total membranes, with four, including a 28-kDal protein, also found in outer membrane preparations.
Conclusions:
- Growth medium significantly influences the expression of Yersinia enterocolitica outer membrane proteins.
- RPMI 1640 medium is a more suitable model for studying in vivo-like protein expression.
- Novel plasmid-encoded outer membrane proteins were identified, potentially contributing to Yersinia enterocolitica virulence.
