You and I: The Effects of Intra- and Inter-Species Interactions on Microbial Biofilms, Growth, and Morphology

Humanity is shaped by its relationships with microbes. From bacterial infections to the production of biofuels, industry and health often hinge on our control of microbial populations. Understanding the physiological and genetic basis of their behaviors is therefore of the highest importance. To this end I have investigated the genetic basis of plastic adhesion in Saccharomyces cerevisiae, the mechanistic and evolutionary dynamics of mixed species biofilms with Escherichia coli and S. cerevisiae, and the induction of filamentation in E. coli. Using a bulk segregant analysis on experimentally evolved populations, I detected 28 genes that are likely to mediate plastic adhesion in S. cerevisiae. With a variety of imaging and culture manipulation techniques, I found that particular strains of E. coli are capable of inducing flocculation and macroscopic biofilm formation via coaggregation with yeast. I also employed experimental evolution and microbial demography techniques to find that selection for mixed species biofilm association leads to lower fecundity in S. cerevisiae. Using culture manipulation and imaging techniques, I also found that E. coli are capable of inducing a filamentous phenotype with a secreted signal that has many of the qualities of a quorum sensing molecule.

Who Do You Say I Am?: African American Women Clergy and the Construction of Ministerial Identity

The purpose of this study was to examine how African American women in ordained ministry construct and develop ministerial identity in the context of the Black Church. This study employed a qualitative multicase study methodology and the purposive participant sample was comprised of 13 women who were ordained or pursuing ordination in the Baltimore or Washington conferences of the AME Church. Semistructured in-depth interviews were conducted with the participants, and member checks were employed as a triangulation method. This study reveals that the primary factor impacting ministerial identity development is the relationship with the senior pastor and explores the various ways in which that impact is felt. This study also connects aspects of that relationship and its resulting impact to African American cultural traditions and values, as well as offers several suggestions to women cultivating ministerial identity and the organizational systems within which that process occurs.