Purification and some properties of two boticins

Area of Science:

• Microbiology
• Bacteriology
• Molecular Biology

Background:

• Clostridium botulinum type E produces toxins causing botulism.
• Nontoxigenic variants may possess antimicrobial properties.
• Bacteriocins are ribosomally synthesized antimicrobial peptides.

Purpose of the Study:

• To isolate and characterize bacteriocins (boticins) from a nontoxigenic Clostridium botulinum type E strain.
• To evaluate the antimicrobial activity of purified boticins against C. botulinum type E.

Main Methods:

• Gel filtration (Sephadex G-50) for initial separation.
• Density gradient ultracentrifugation for large boticin isolation.
• Continuous curtain electrophoresis and sulfoethyl-Sephadex chromatography for small boticin purification.
• Characterization of boticin properties (molecular weight, charge, stability).

Main Results:

• Two distinct boticins (large and small) were purified with high yields.
• Small boticin: basic, MW < 30,000, predominant.
• Large boticin: negatively charged, MW > 40 x 10(6), <20% activity.
• Both boticins showed heat resistance and susceptibility to proteases.
• Small boticin rapidly killed vegetative C. botulinum type E cells.

Conclusions:

• Nontoxigenic Clostridium botulinum type E can produce active bacteriocins.
• Purified boticins exhibit significant bactericidal and sporostatic effects.
• These bacteriocins represent potential agents for controlling C. botulinum type E growth.