Induction and Isolation of Bacteriophages from the Spoilage Bacterium Lactobacillus

Presenter Information

Kyle Larson

Document Type

Oral Presentation

Campus where you would like to present

SURC Ballroom A

Start Date

17-5-2012

End Date

17-5-2012

Abstract

Due to the complex multi-step nature of wine-making, the introduction of unwanted bacteria like Lactobacilli during production can lead to serious contamination problems. The goal of this project is to isolate bacteriophages (bacterial viruses), from Lactobacillus populations isolated from local wineries and vineyards. Once isolated, the bacteriophages can be tested for their ability to infect and kill other wild Lactobacilli. Many bacteriophages have the ability to integrate their DNA into the genome of its host cell as part of its normal replication cycle. The integrated viral DNA is termed a prophage and it can remain in the genome over many generations of bacterial reproduction. Viral replication will resume only after the host bacterium experiences physiological stress, which triggers excision of the prophage DNA, ultimately killing the host and releasing infectious viruses from the host cells. Like many bacteria, Lactobacilli can harbor prophage DNA within their genomes. In this project, prophage viruses were recovered from their bacterial hosts by chemically damaging the host’s DNA (a stressful event) to initiate the lytic cycle of viral reproduction. A total of 38 wild Lactobacilli were isolated and, under various stress conditions, 17 showed signs of prophage induction. To test for virulence, these 17 prophage isolates were then exposed to other Lactobacilli species, but did not cause infection. Although prophages have been identified in Lactobacilli associated and isolated from wine, the host range for these prophages appears to be too narrow for use as for treatment of contaminated wine.

Poster Number

16

Faculty Mentor(s)

Holly Pinkart, Lucinda Carnell, Gabrielle Stryker

Additional Mentoring Department

Biological Sciences

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May 17th, 8:30 AM May 17th, 11:00 AM

Induction and Isolation of Bacteriophages from the Spoilage Bacterium Lactobacillus

SURC Ballroom A

Due to the complex multi-step nature of wine-making, the introduction of unwanted bacteria like Lactobacilli during production can lead to serious contamination problems. The goal of this project is to isolate bacteriophages (bacterial viruses), from Lactobacillus populations isolated from local wineries and vineyards. Once isolated, the bacteriophages can be tested for their ability to infect and kill other wild Lactobacilli. Many bacteriophages have the ability to integrate their DNA into the genome of its host cell as part of its normal replication cycle. The integrated viral DNA is termed a prophage and it can remain in the genome over many generations of bacterial reproduction. Viral replication will resume only after the host bacterium experiences physiological stress, which triggers excision of the prophage DNA, ultimately killing the host and releasing infectious viruses from the host cells. Like many bacteria, Lactobacilli can harbor prophage DNA within their genomes. In this project, prophage viruses were recovered from their bacterial hosts by chemically damaging the host’s DNA (a stressful event) to initiate the lytic cycle of viral reproduction. A total of 38 wild Lactobacilli were isolated and, under various stress conditions, 17 showed signs of prophage induction. To test for virulence, these 17 prophage isolates were then exposed to other Lactobacilli species, but did not cause infection. Although prophages have been identified in Lactobacilli associated and isolated from wine, the host range for these prophages appears to be too narrow for use as for treatment of contaminated wine.