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Published on: May 28, 2012
PURIFICATION OF THE SOLUBLE HEMOLYSINS OF LISTERIA MONOCYTOGENES
Abstract:
Jenkins, E. M. (Tuskegee Institute, Tuskegee, Ala.), A. N. Njoku-Obi, and E. W. Adams. Purification of the soluble hemolysins of Listeria monocytogenes. J. Bacteriol. 88:418-424. 1964.-A method is described for obtaining relatively purified hemolysin preparations from both virulent and avirulent strains of Listeria monocytogenes. These hemolysins are protein in nature as shown by heat lability, nondialyzable properties, precipitation with trichloroacetic acid, and electrophoretic mobility. The hemolysins are antigenic in rabbits as shown by serum neutralization tests. The potency of the purified hemolysin was markedly increased by cysteine, sodium hydrosulfite, and a number of reducing agents. Many of the actions of the purified hemolysin seemed to parallel that of streptolysin O, and certain of these activities could be explained by the "thioldisulfide hypothesis."
Insights
Researchers purified soluble hemolysins from Listeria monocytogenes, finding they are heat-labile proteins. Their potency increased with reducing agents, suggesting a thioldisulfide mechanism.
Area of Science:
- Microbiology
- Protein Chemistry
Background:
- Listeria monocytogenes is a bacterial pathogen.
- Hemolysins are toxins that lyse red blood cells.
- Understanding bacterial toxins is crucial for pathogenesis research.
Purpose of the Study:
- To develop a method for purifying hemolysins from Listeria monocytogenes.
- To characterize the biochemical and physical properties of these hemolysins.
- To investigate factors affecting hemolysin potency.
Main Methods:
- Bacterial culture and extraction of soluble hemolysins.
- Biochemical assays including heat lability, dialysis, trichloroacetic acid precipitation, and electrophoresis.
- Immunological tests (serum neutralization) in rabbits.
- Potency assays with various reducing agents.
Main Results:
- Relatively purified hemolysin preparations were obtained from both virulent and avirulent Listeria monocytogenes strains.
- Hemolysins were confirmed as proteins based on heat lability, non-dialyzable properties, precipitation with trichloroacetic acid, and electrophoretic mobility.
- The hemolysins demonstrated antigenicity in rabbits.
- Hemolysin potency was significantly enhanced by cysteine, sodium hydrosulfite, and other reducing agents.
Conclusions:
- A method for purifying Listeria monocytogenes hemolysins was established.
- These hemolysins are antigenic proteins.
- Their activity is modulated by reducing agents, potentially via a thioldisulfide hypothesis, similar to streptolysin O.
