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Isolation of a plasmid responsible for caseinase activity in Clostridium perfringens ATCC 3626B
Abstract:
Clostridium perfringens strain ATCC 3626B was cured of caseinase activity at a high frequency after treatment with acriflavine dye (2.5%) or elevated temperature growth (9.1%). Caseinase-negative isolates retained the larger (9.4 megadaltons) pHB102 cryptic plasmid, but were missing the smaller (2.1 megadaltons) pHB101 plasmid present in the caseinase-positive wild-type strain. Dye-buoyant density-gradient centrifugation at 4 or 15 degrees C revealed that the pHB101 and pHB102 plasmids are temperature labile and easily converted into the nicked non-supercoiled or linear state.
Insights
Clostridium perfringens caseinase activity was lost by removing the pHB101 plasmid using acriflavine dye or heat. The pHB101 and pHB102 plasmids are temperature-sensitive, affecting bacterial enzyme production.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Genetics
Background:
- Clostridium perfringens is an important bacterial pathogen.
- Caseinase activity is a virulence factor in some bacterial species.
- Plasmid loss can result in loss of bacterial traits.
Purpose of the Study:
- To investigate the genetic basis of caseinase activity in Clostridium perfringens.
- To determine the role of plasmids in Clostridium perfringens caseinase production.
- To characterize the stability of Clostridium perfringens plasmids under different conditions.
Main Methods:
- Treatment of Clostridium perfringens strain ATCC 3626B with acriflavine dye.
- Cultivation of Clostridium perfringens at elevated temperatures.
- Plasmid DNA extraction and analysis using dye-buoyant density-gradient centrifugation.
- Comparison of plasmid profiles between caseinase-positive and caseinase-negative isolates.
Main Results:
- A high frequency of caseinase-negative Clostridium perfringens isolates was obtained after acriflavine treatment or heat growth.
- Caseinase-negative isolates lacked the smaller pHB101 plasmid (2.1 megadaltons) but retained the larger pHB102 plasmid (9.4 megadaltons).
- Dye-buoyant density-gradient centrifugation showed that both pHB101 and pHB102 plasmids are temperature labile and can become nicked or linearized at lower temperatures (4 or 15 degrees C).
Conclusions:
- The pHB101 plasmid is essential for caseinase activity in Clostridium perfringens strain ATCC 3626B.
- Environmental factors like temperature can influence plasmid stability and bacterial phenotype.
- Understanding plasmid dynamics is crucial for studying bacterial virulence and genetics.