Event Title

Looking for Evidence of Predator-Mediated Apparent Competition Between Escherichia coli and Salmonella typhimurium Using PRD1 Bacteriophage

Location

Steelcase Lecture Hall

Start Date

31-3-2011 4:30 PM

Description

INTRODUCTION: Apparent competition is an indirect interaction between two (or more) species that are preyed upon by a common predator. This ecological principle has been previously demonstrated through interactions between diverse organisms ranging from sea urchins to rodents but also in laboratory constructed microcosms. In apparent competition, one of the host consumers is able to support a greater amount of predation which indirectly causes the decline of the other host consumer. By placing the pathogenically important gram negative bacteria Escherichia coli and Salmonella typhimurium with a common predator, we hope to demonstrate this principle. The shared predator used is PRD1 bacteriophage, capable of infecting a broad range of gram negative hosts through the use of conjugative plasmids. METHODS: Populations of E. coli and S. typhimurium will be compared when alone, in coexistence, and in the presence and absence of PRD1. Test tubes inoculated in triplicate with the indicated species will be monitored over the period of seven days. Each day, samples from the tubes will be taken, diluted, and plated on various all-purpose and selective media. RESULTS: Results for the majority of the experiments are pending. Data collected and interpreted thus far lead us to believe that with the use of PRD1, an indirect interaction exists between E. coli and S. typhimurium.

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Mar 31st, 4:30 PM

Looking for Evidence of Predator-Mediated Apparent Competition Between Escherichia coli and Salmonella typhimurium Using PRD1 Bacteriophage

Steelcase Lecture Hall

INTRODUCTION: Apparent competition is an indirect interaction between two (or more) species that are preyed upon by a common predator. This ecological principle has been previously demonstrated through interactions between diverse organisms ranging from sea urchins to rodents but also in laboratory constructed microcosms. In apparent competition, one of the host consumers is able to support a greater amount of predation which indirectly causes the decline of the other host consumer. By placing the pathogenically important gram negative bacteria Escherichia coli and Salmonella typhimurium with a common predator, we hope to demonstrate this principle. The shared predator used is PRD1 bacteriophage, capable of infecting a broad range of gram negative hosts through the use of conjugative plasmids. METHODS: Populations of E. coli and S. typhimurium will be compared when alone, in coexistence, and in the presence and absence of PRD1. Test tubes inoculated in triplicate with the indicated species will be monitored over the period of seven days. Each day, samples from the tubes will be taken, diluted, and plated on various all-purpose and selective media. RESULTS: Results for the majority of the experiments are pending. Data collected and interpreted thus far lead us to believe that with the use of PRD1, an indirect interaction exists between E. coli and S. typhimurium.