Abstract
Strains of the fish pathogen Aeromonas salmonicida which possess the cell surface protein array known as the A-layer (A+) involved in virulence formed deep red colonies on tryptic soy agar containing 30 micrograms of Congo red per ml. These were readily distinguished from colorless or light orange colonies of avirulent mutants lacking A-layer (A-). The utility of Congo red agar for quantifying A+ and A- cells in the routine assessment of culture virulence was demonstrated. Intact A+ cells adsorbed Congo red, whereas A- mutants did not bind Congo red unless first permeabilized with EDTA. The dye-binding component of A+ cells was shown to be the 50,000-Mr A-protein component of the surface array. Purified A-protein avidly bound Congo red at a dye-to-protein molar ratio of about 30 by a nonspecific hydrophobic mechanism enhanced by high salt concentrations. Neither A+ nor A- cells adsorbed to Congo red-Sepharose columns at low salt concentrations. On the other hand, A+ (but not A-) cells were avidly bound at high salt concentrations.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chart H., Shaw D. H., Ishiguro E. E., Trust T. J. Structural and immunochemical homogeneity of Aeromonas salmonicida lipopolysaccharide. J Bacteriol. 1984 Apr;158(1):16–22. doi: 10.1128/jb.158.1.16-22.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Daskaleros P. A., Payne S. M. Cloning the gene for Congo red binding in Shigella flexneri. Infect Immun. 1985 Apr;48(1):165–168. doi: 10.1128/iai.48.1.165-168.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evenberg D., Lugtenberg B. Cell surface of the fish pathogenic bacterium Aeromonas salmonicida. II. Purification and characterization of a major cell envelope protein related to autoagglutination, adhesion and virulence. Biochim Biophys Acta. 1982 Jan 22;684(2):249–254. doi: 10.1016/0005-2736(82)90013-x. [DOI] [PubMed] [Google Scholar]
- Ishiguro E. E., Kay W. W., Ainsworth T., Chamberlain J. B., Austen R. A., Buckley J. T., Trust T. J. Loss of virulence during culture of Aeromonas salmonicida at high temperature. J Bacteriol. 1981 Oct;148(1):333–340. doi: 10.1128/jb.148.1.333-340.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kay W. W., Buckley J. T., Ishiguro E. E., Phipps B. M., Monette J. P., Trust T. J. Purification and disposition of a surface protein associated with virulence of Aeromonas salmonicida. J Bacteriol. 1981 Sep;147(3):1077–1084. doi: 10.1128/jb.147.3.1077-1084.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kay W. W., Phipps B. M., Ishiguro E. E., Olafson R. W., Trust T. J. Surface layer virulence A-proteins from Aeromonas salmonicida strains. Can J Biochem Cell Biol. 1984 Nov;62(11):1064–1071. doi: 10.1139/o84-137. [DOI] [PubMed] [Google Scholar]
- LEIVE L. A NONSPECIFIC INCREASE IN PERMEABILITY IN ESCHERICHIA COLI PRODUCED BY EDTA. Proc Natl Acad Sci U S A. 1965 Apr;53:745–750. doi: 10.1073/pnas.53.4.745. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leive L., Shovlin V. K., Mergenhagen S. E. Physical, chemical, and immunological properties of lipopolysaccharide released from Escherichia coli by ethylenediaminetetraacetate. J Biol Chem. 1968 Dec 25;243(24):6384–6391. [PubMed] [Google Scholar]
- Maurelli A. T., Blackmon B., Curtiss R., 3rd Loss of pigmentation in Shigella flexneri 2a is correlated with loss of virulence and virulence-associated plasmid. Infect Immun. 1984 Jan;43(1):397–401. doi: 10.1128/iai.43.1.397-401.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Munn C. B., Ishiguro E. E., Kay W. W., Trust T. J. Role of surface components in serum resistance of virulent Aeromonas salmonicida. Infect Immun. 1982 Jun;36(3):1069–1075. doi: 10.1128/iai.36.3.1069-1075.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Payne S. M., Finkelstein R. A. Detection and differentiation of iron-responsive avirulent mutants on Congo red agar. Infect Immun. 1977 Oct;18(1):94–98. doi: 10.1128/iai.18.1.94-98.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Phipps B. M., Trust T. J., Ishiguro E. E., Kay W. W. Purification and characterization of the cell surface virulent A protein from Aeromonas salmonicida. Biochemistry. 1983 Jun 7;22(12):2934–2939. doi: 10.1021/bi00281a023. [DOI] [PubMed] [Google Scholar]
- Surgalla M. J., Beesley E. D. Congo red-agar plating medium for detecting pigmentation in Pasteurella pestis. Appl Microbiol. 1969 Nov;18(5):834–837. doi: 10.1128/am.18.5.834-837.1969. [DOI] [PMC free article] [PubMed] [Google Scholar]