Presentation Title

The Importance of Virulence Factors in the Growth and Infection Cycle of Listeria

Faculty Mentor

Kurt Schesser

Start Date

18-11-2017 10:00 AM

End Date

18-11-2017 11:00 AM

Location

BSC-Ursa Minor 42

Session

Poster 1

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Listeria monocytogenes is a common bacterium that causes human infections, like miscarriage and septicemia. Listeria uses specific virulence factors to produce proteins that will assist in invasion, replication, and escape. By manipulation of the virulence factors through knockout mutants, this study observed their role and importance in the infection and proliferation life cycle. JEG-3 cells, a human placental line, were infected with wild type Listeria or knockout mutants of individual virulence factors, Internalin A&B, Listeriolysin O, and ActA. Through Colony Forming Unit Assay, it was possible to analyze the number of colonies representing the number of Listeria bacteria after definitive time points. Each virulence factor did play a significant role in the growth and infection of Listeria in the JEG-3 cells as fewer colonies were found in the knockout mutant plates than the wild type. Each virulence factor affected a distinct portion of the invasion, replication, and escape cycle. The omission of a single virulence factor will significantly disrupt the growth and infection life cycle of Listeria. The role of the Listerial virulence factors were tested in JEG-3 cells, but can have different roles in different cell types, like macrophages. Further studies must be done to determine the effect of these specific virulence factors in other cell lines.

Summary of research results to be presented

Through our experimentation and research, I compared the knockout mutants of each of the virulence factors, Internalin A&B, Listeriolysin O, and ActA. In conclusion, the virulence factors did play a significant role in the growth and infection of Listeria in the JEG-3 cells. The Internalin AB mutant showed a significant decrease in infection compared to the wildtype Listeria. Without Internalin AB, very small amounts of Listeria could invade the cell.The Listeriolysin O mutant also showed a significant decrease in infection and growth compared to the wildtype Listeria. Without Listeriolysin O, very small amounts of Listeria could grow and replicate within the cytosol. The ActA mutant showed a decrease in cell to cell invasion when comparing the fold increase. The mutant invades and replicates at the same rate, but the fold increase is significantly smaller. All the virulence factors displayed a pivotal role in the Listeria’s invasion, replication, and escape. These experiments show the role of virulence factors in JEG-3 cell line, but must be further studied in different cell lines, like macrophages.

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Nov 18th, 10:00 AM Nov 18th, 11:00 AM

The Importance of Virulence Factors in the Growth and Infection Cycle of Listeria

BSC-Ursa Minor 42

Listeria monocytogenes is a common bacterium that causes human infections, like miscarriage and septicemia. Listeria uses specific virulence factors to produce proteins that will assist in invasion, replication, and escape. By manipulation of the virulence factors through knockout mutants, this study observed their role and importance in the infection and proliferation life cycle. JEG-3 cells, a human placental line, were infected with wild type Listeria or knockout mutants of individual virulence factors, Internalin A&B, Listeriolysin O, and ActA. Through Colony Forming Unit Assay, it was possible to analyze the number of colonies representing the number of Listeria bacteria after definitive time points. Each virulence factor did play a significant role in the growth and infection of Listeria in the JEG-3 cells as fewer colonies were found in the knockout mutant plates than the wild type. Each virulence factor affected a distinct portion of the invasion, replication, and escape cycle. The omission of a single virulence factor will significantly disrupt the growth and infection life cycle of Listeria. The role of the Listerial virulence factors were tested in JEG-3 cells, but can have different roles in different cell types, like macrophages. Further studies must be done to determine the effect of these specific virulence factors in other cell lines.