SURVIVAL OF ESCHERICHIA COLI IN AGRICULTURAL SOILS AND STUDENT ENGAGEMENT IN ONLINE DISCUSSIONS
Truhlar, Allison Mary
There is great interest in identifying manure management techniques to minimize the persistence of pathogenic Escherichia coli in agricultural fields and, thereby, decrease the risk of downstream contamination and human infection. The first two chapters of this dissertation seek to determine the how the agricultural environmental variable of manure application method shapes the genetic and phenotypic population structure of E. coli. First, we conducted a field and laboratory experiment that demonstrated the expression of extracellular fibers called curli, which are linked to environmental persistence of E. coli, was linked to surface-application of manure, as opposed to incorporation into the soil. Second, we applied whole genome sequencing technology to isolates collected from laboratory microcosms with differing manure application treatments. We found no systematic genomic differences (i.e. individual-level selection) that could be explained by week or manure application treatment. As higher education institutions offer online courses to growing audiences, there is increasing desire to understand how best to engage students. The third chapter of this dissertation examines the effects of assigning chat roles and facilitating self and group reflection on student-content and student-student interaction outcomes in synchronous online chats. Group reflections were the only intervention that had a significant effect on both outcomes.
Online discussions; Whole genome sequencing; Educational technology; Microbiology; Curli; Escherichia coli; Group reflection; Manure application
Walter, Michael Todd
Williams, Kimberly; Hay, Anthony G.; Richardson, Ruth E.
Biological and Environmental Engineering
Ph. D., Biological and Environmental Engineering
Doctor of Philosophy
dissertation or thesis