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Identification and partial characterization of an Actinomyces pyogenes hemolysin
1Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5605, USA.
Veterinary Microbiology
|May 1, 1996
Summary
Actinomyces pyogenes hemolysin, isolated from cattle liver abscesses, is oxygen-stable but sensitive to heat and pH extremes. This study characterizes its properties and identifies two distinct hemolysin proteins, also finding co-occurring leukotoxin activity.
Area of Science:
- Veterinary Microbiology
- Bacterial Pathogenesis
- Protein Biochemistry
Background:
- Hepatic abscesses are a significant economic concern in cattle production.
- Actinomyces pyogenes is a common bacterial pathogen associated with bovine abscesses.
- Understanding bacterial virulence factors like hemolysins is crucial for disease control.
Purpose of the Study:
- To characterize the hemolytic activity of Actinomyces pyogenes isolates from bovine hepatic abscesses.
- To investigate the optimal conditions for hemolysin production.
- To identify the biochemical properties and molecular characteristics of the hemolysin(s).
Main Methods:
- Bacterial isolates from hepatic abscesses were cultured in various media under different atmospheric conditions.
- Hemolytic activity was assessed using sheep erythrocytes and tested against various chemical agents, temperatures, and pH levels.
- Protein analysis techniques including differential filtration, isoelectric focusing, and SDS-PAGE were employed to characterize hemolysin proteins.
- Leukotoxin activity in cell-free supernatants was also screened.
Main Results:
- Actinomyces pyogenes hemolysin demonstrated oxygen stability but was inactivated by heat (56°C, 100°C) and extreme pH (3, 11).
- Protease, trypsin, and amylase treatments degraded hemolytic activity.
- Maximum hemolysin production occurred in brain heart infusion (BHI) broth incubated aerobically with 6% CO2.
- Two hemolysin proteins with estimated molecular masses of 62 kDa and 58 kDa were identified.
- Significant leukotoxin activity was detected concurrently with hemolysin.
Conclusions:
- Actinomyces pyogenes produces a robust hemolysin with specific stability characteristics relevant to the host environment.
- The identified hemolysin proteins and their associated leukotoxin activity likely contribute to the pathogenesis of bovine hepatic abscesses.
- Optimized culture conditions in BHI broth with CO2 enhance hemolysin yield for further study.