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Characterization of plasmids from Listeria sp.
J Kolstad1, L M Rørvik, P E Granum
1Department of Food Hygiene, Norwegian College of Veterinary Medicine, Oslo.
International Journal of Food Microbiology
|February 1, 1991
Summary
Most Listeria isolates, primarily Listeria monocytogenes, harbor extrachromosomal DNA. Further analysis revealed significant genetic similarity among the detected plasmids, suggesting a common origin or exchange mechanism in Listeria populations.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Extrachromosomal DNA, particularly plasmids, plays a crucial role in bacterial adaptation and virulence.
- Understanding plasmid diversity and characteristics in Listeria species is important for food safety and public health.
Purpose of the Study:
- To investigate the prevalence of extrachromosomal DNA in Listeria isolates.
- To characterize the plasmids found in Listeria isolates through molecular techniques.
Main Methods:
- Agarose gel electrophoresis was used to separate and visualize plasmid DNA.
- Restriction analysis and hybridization experiments were performed to assess plasmid homology.
Main Results:
- A high prevalence (78%) of extrachromosomal DNA was detected in 139 Listeria isolates, predominantly Listeria monocytogenes.
- Fifty-one isolates contained plasmids, with most having a single plasmid of varying sizes.
- Restriction and hybridization analyses indicated substantial genetic homology among the investigated plasmids, with one exception.
Conclusions:
- Extrachromosomal DNA is common in Listeria isolates, with plasmids being a significant component.
- The high degree of homology among plasmids suggests conserved genetic elements or horizontal gene transfer within Listeria species.