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Partial purification and biological activity of the enterotoxic component of Pseudomonas aeruginosa
V Majtán1, A Hostacká, L Klokocníková
1Research Institute of Preventive Medicine, Bratislava, Czechoslovakia.
Abstract:
From an Pseudomonas aeruginosa strain isolated from feces of a patient with clinical manifestation of diarrhoeal disease a filtrate from the culture in proteose peptone broth was prepared. After concentration, the culture filtrate was separated on Sephadex G-100 column in four fractions. The first high molecular fraction (F1) represented components of relative molecular mass exceeding 100,000, the second fraction those about 58,000, the third fraction those about 23,000 and the fourth one was composed from low molecular components of molecular mass lower than 10,000. In biological tests, the most marked reactions were caused by the third fraction. It caused a fluid accumulation in the rabbit ileal loop test, reactions in the rapid and delayed skin tests and in the mouse foot edema test. Besides these activities the third fraction caused also a hemolytic, proteolytic and elastase activity. A clear cytotoxic effect of this fraction was seen on Vero, Y1 and CHO cell lines. It was also found, that after heating (100 degrees C/10 min) both, the enterotoxic and hemolytic activities were lost.
Insights
Pseudomonas aeruginosa secretes factors causing diarrhea and cell damage. A specific fraction (23,000 molecular weight) showed significant enterotoxic, hemolytic, and cytotoxic effects, which were lost upon heating.
Area of Science:
- Microbiology
- Toxicology
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen often associated with infections.
- Diarrheal diseases can be caused by bacterial toxins.
- Understanding bacterial virulence factors is crucial for developing treatments.
Purpose of the Study:
- To isolate and characterize virulence factors from Pseudomonas aeruginosa.
- To investigate the biological activities of different molecular weight fractions of the bacterial filtrate.
- To determine the heat lability of observed activities.
Main Methods:
- Culture filtrate preparation from Pseudomonas aeruginosa.
- Fractionation using Sephadex G-100 chromatography.
- Biological assays including rabbit ileal loop test, skin tests, mouse foot edema test, hemolysis, and cytotoxicity assays.
- Heat treatment to assess activity stability.
Main Results:
- Four molecular weight fractions were obtained, with the third fraction (approx. 23,000 MW) exhibiting the most significant biological activities.
- The third fraction demonstrated enterotoxic, hemolytic, proteolytic, elastase, and cytotoxic effects on cell lines.
- Both enterotoxic and hemolytic activities were abolished after heating the fraction at 100°C for 10 minutes.
Conclusions:
- Pseudomonas aeruginosa produces potent virulence factors, including enterotoxins and hemolysins, with a molecular weight around 23,000.
- These factors contribute to the pathogenicity of the bacteria, causing fluid accumulation and cell damage.
- The heat-labile nature of these toxins suggests potential therapeutic targets.