Use of real-time quantitative PCR for the analysis of phiLC3 prophage stability in lactococci
| Autor: | Merete Lunde, Ingolf F. Nes, Janet Martha Blatny, Are H. Aastveit, Dag Lillehaug |
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| Rok vydání: | 2003 |
| Předmět: |
Prophages
Virus Integration Molecular Sequence Data Applied Microbiology and Biotechnology Polymerase Chain Reaction Microbiology Bacteriophage Bacteriolysis Lysogenic cycle Methods Bacteriophages Lysogeny Prophage Ecology biology Lactococcus lactis Temperature biology.organism_classification Temperateness Lytic cycle Attachment Sites Microbiological DNA Viral Bacteria Food Science Biotechnology |
| Zdroj: | Applied and environmental microbiology. 69(1) |
| ISSN: | 0099-2240 |
| Popis: | Bacteriophages are a common and constant threat to proper milk fermentation. It has become evident that lysogeny is widespread in lactic acid bacteria, and in this work the temperate lactococcal bacteriophage φLC3 was used as a model to study prophage stability in lactococci. The stability was analyzed in six φLC3 lysogenic Lactococcus lactis subsp. cremoris host strains when they were growing at 15 and 30°C. In order to perform these analyses, a real-time PCR assay was developed. The stability of the φLC3 prophage was found to vary with the growth phase of its host L. lactis IMN-C1814, in which the induction rate increased during the exponential growth phase and reached a maximum level when the strain was entering the stationary phase. The maximum spontaneous induction frequency of the φLC3 prophage varied between 0.32 and 9.1% (28-fold) in the six lysogenic strains. No correlation was observed between growth rates of the host cells and the spontaneous prophage induction frequencies. Furthermore, the level of extrachromosomal phage DNA after induction of the prophage varied between the strains (1.9 to 390%), and the estimated burst sizes varied up to eightfold. These results show that the host cells have a significant impact on the lytic and lysogenic life styles of temperate bacteriophages. The present study shows the power of the real-time PCR technique in the analysis of temperate phage biology and will be useful in work to reveal the impact of temperate phages and lysogenic bacteria in various ecological fields. |
| Databáze: | OpenAIRE |
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