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Characterization of a bacteriocinogenic plasmid in Clostridium perfringens CW55
Abstract:
A bacteriocinogenic strain of Clostridium perfringens was exposed to various curing agents known to accelerate the elimination of extrachromosomal DNA, and 20 independently derived mutants that had lost both the ability to produce bacteriocin and their immunity to it were isolated and characterized. All of the mutants were missing at least two specific plasmid bands seen in the agarose gel plasmid profile of the parent strain. Evidence that the two missing bands represented the open circular and closed circular forms of the same plasmid was obtained by X-ray nicking and restriction endonuclease digestion. The data indicated that bacteriocin production and immunity are controlled by a single plasmid, pCW4, with a molecular weight of 5.6 x 10(6) in this strain. Attempts to transfer the bacteriocinogenic plasmid were unsuccessful.
Insights
Clostridium perfringens bacteriocin production and immunity are controlled by a single plasmid, pCW4. Loss of this plasmid in mutants resulted in the elimination of both traits.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Clostridium perfringens produces bacteriocins, which are antimicrobial peptides.
- Extrachromosomal DNA, specifically plasmids, often carries genes for bacteriocin production and immunity.
- Understanding plasmid function is crucial for controlling bacterial traits.
Purpose of the Study:
- To identify the plasmid responsible for bacteriocin production and immunity in a Clostridium perfringens strain.
- To characterize mutants that have lost these traits.
Main Methods:
- Exposure of Clostridium perfringens to curing agents to eliminate plasmids.
- Isolation and characterization of bacteriocin-negative and immunity-deficient mutants.
- Agarose gel electrophoresis to analyze plasmid profiles.
- X-ray nicking and restriction endonuclease digestion to confirm plasmid identity.
Main Results:
- Twenty mutants lacking bacteriocin production and immunity were isolated.
- All mutants were missing at least two plasmid bands.
- Evidence confirmed these bands represented different forms of the same plasmid.
- Bacteriocin production and immunity were attributed to a single plasmid, pCW4 (5.6 x 10^6 molecular weight).
Conclusions:
- A single plasmid, pCW4, controls bacteriocin production and immunity in this Clostridium perfringens strain.
- Loss of pCW4 eliminates both bacteriocin production and immunity.
- The bacteriocinogenic plasmid could not be transferred between strains.