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Molecular identification of potentially probiotic lactobacilli
1Food Research and Development Centre, Agriculture and Agrifood Canada, 3600 Casavant Blvd. West, Saint-Hyacinthe, Québec, Canada, J2S 8E3.
Current Microbiology
|November 24, 1999
Summary
Randomly amplified polymorphic DNA (RAPD) analysis differentiated 73 lactobacilli strains into seven clusters, clarifying species within the Lactobacillus acidophilus complex. This method accurately identified species, including Lactobacillus gallinarum, which was characterized for the first time.
Area of Science:
- Microbiology
- Genetics
Background:
- Oligonucleotide probes are useful for identifying several Lactobacillus species.
- A probe for Lactobacillus helveticus cross-hybridized with Lactobacillus gallinarum, necessitating a more precise identification method.
Purpose of the Study:
- To evaluate the similarity among 73 Lactobacillus strains using randomly amplified polymorphic DNA (RAPD) profiles.
- To accurately differentiate species within the Lactobacillus acidophilus complex and characterize Lactobacillus gallinarum.
Main Methods:
- Utilized randomly amplified polymorphic DNA (RAPD) profiles from five single-primer reactions to assess strain similarity.
- Employed pulsed-field gel electrophoresis (PFGE) for the characterization of Lactobacillus gallinarum strains.
Main Results:
- Grouped 73 Lactobacillus strains into seven clusters at a 30% similarity level, corresponding to six species of the L. acidophilus complex and L. helveticus.
- For the first time, RAPD and PFGE analyses were used to characterize L. gallinarum strains.
- Estimated the genome length of L. gallinarum to be approximately 1.45 Mb (ApaI fragments) and 1.95 Mb (SmaI fragments).
Conclusions:
- RAPD analysis provides a reliable method for differentiating species within the Lactobacillus acidophilus complex.
- This study successfully distinguished between closely related Lactobacillus species, including the novel characterization of L. gallinarum.