Title

Environmental Gradients as Drivers of Virus-Mediated Microbial Evolution

Presenter Information

Laura Adams

Document Type

Oral Presentation

Location

SURC 137B

Start Date

16-5-2013

End Date

16-5-2013

Abstract

Bacterial viruses (phage) influence microbial community structure and genetic diversity through selective pressure resulting from viral parasitism, but also more directly by horizontal transfer of DNA between bacteria in a process called transduction. Environmental stress can induce and accelerate transduction, a situation often made obvious in extreme environments. Soap Lake is an alkaline, permanently stratified lake that has maintained its meromixis for over 2,000 years. Its deep monimolimnion layer provides an environment of great physical and chemical stability. The half meter chemocline zone that separates the lower and upper lake layers bridges temperature differentials, is an oxic/anoxic interface, and transitions a hypersaline zone (141 gL-1 TDS) to a brackish one (12-16 gL-1 TDS). Since rapid changes in environmental conditions can induce viral transduction events, these areas should have larger populations of phage, and the prokaryotes inhabiting these areas will experience greater rates of viral infection (and subsequent gene transfers) than more stable environments. This project measured viral abundance and host infection rates along these gradients, and compared those data to the viral populations and host infection rates in the highly stable zones. Two-way analysis of variance (ANOVA) was used to test for differences in host populations and phage infection rates between sampling dates and collection sites.

Faculty Mentor(s)

Holly Pinkart

Additional Mentoring Department

Biological Sciences

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May 16th, 11:40 AM May 16th, 12:00 PM

Environmental Gradients as Drivers of Virus-Mediated Microbial Evolution

SURC 137B

Bacterial viruses (phage) influence microbial community structure and genetic diversity through selective pressure resulting from viral parasitism, but also more directly by horizontal transfer of DNA between bacteria in a process called transduction. Environmental stress can induce and accelerate transduction, a situation often made obvious in extreme environments. Soap Lake is an alkaline, permanently stratified lake that has maintained its meromixis for over 2,000 years. Its deep monimolimnion layer provides an environment of great physical and chemical stability. The half meter chemocline zone that separates the lower and upper lake layers bridges temperature differentials, is an oxic/anoxic interface, and transitions a hypersaline zone (141 gL-1 TDS) to a brackish one (12-16 gL-1 TDS). Since rapid changes in environmental conditions can induce viral transduction events, these areas should have larger populations of phage, and the prokaryotes inhabiting these areas will experience greater rates of viral infection (and subsequent gene transfers) than more stable environments. This project measured viral abundance and host infection rates along these gradients, and compared those data to the viral populations and host infection rates in the highly stable zones. Two-way analysis of variance (ANOVA) was used to test for differences in host populations and phage infection rates between sampling dates and collection sites.