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Partial purification of an osteolytic toxin from Pasteurella multocida
Abstract:
A protein toxin apparently composed of one polypeptide with an estimated Mr of 155,000 was purified from sonicated cells of a type D strain of Pasteurella multocida (LFB3) by preparative polyacrylamide gel electrophoresis (PAGE) and DEAE-Sephadex A50 chromatography. Its specific activity was 150-fold greater than that of the crude extract. The partially purified protein was cytotoxic for embryonic bovine lung cells, lethal for mice and caused turbinate atrophy in gnotobiotic pigs; a single intraperitoneal injection of approximately 360 ng kg-1 caused 50% turbinate atrophy. Reversal of the two-step purification procedure using DEAE-Sephacel chromatography followed by preparative PAGE increased the yield of toxin 30-fold; the specific activity of the partially purified toxin was 1970-fold greater than that of the crude extract.
Insights
Researchers purified a Pasteurella multocida toxin responsible for significant turbinate atrophy in pigs. This potent protein toxin shows high specific activity and cytotoxicity, offering insights into bacterial pathogenesis.
Area of Science:
- Bacteriology
- Toxinology
- Veterinary Pathology
Background:
- Pasteurella multocida is an important bacterial pathogen in various animal species.
- Certain strains of Pasteurella multocida produce toxins that contribute to disease pathogenesis, including respiratory tract infections.
- Understanding the specific toxins and their mechanisms is crucial for developing effective control and treatment strategies.
Purpose of the Study:
- To purify and characterize a specific protein toxin from a type D strain of Pasteurella multocida (LFB3).
- To assess the biological activity and pathogenic potential of the purified toxin.
- To improve the purification yield and specific activity of the toxin.
Main Methods:
- Purification of the toxin using preparative polyacrylamide gel electrophoresis (PAGE) and ion-exchange chromatography (DEAE-Sephadex A50).
- Assay of cytotoxic effects on embryonic bovine lung cells.
- Evaluation of lethal effects in mice and induction of turbinate atrophy in gnotobiotic pigs.
- Optimization of the purification strategy using DEAE-Sephacel chromatography followed by preparative PAGE.
Main Results:
- A single polypeptide protein toxin with an estimated molecular weight of 155,000 was isolated.
- The purified toxin exhibited a 150-fold increase in specific activity compared to the crude extract.
- The toxin demonstrated cytotoxicity, lethality in mice, and induced significant turbinate atrophy in pigs at low doses (360 ng kg-1).
- An optimized purification procedure yielded a 30-fold increase in toxin yield and a 1970-fold greater specific activity.
Conclusions:
- A potent protein toxin from Pasteurella multocida was successfully purified and characterized.
- The toxin is a key factor in causing turbinate atrophy, a significant condition in swine respiratory disease.
- The enhanced purification methods significantly improved toxin yield and specific activity, facilitating further research into its structure and function.
