Stephanie Strand

I am currently focusing on identification of proteins involved in signal transduction pathways required for H. capsulatum to sense and respond to changes in environmental conditions. H. capsulatum grows successfully in a variety of disparate environmental conditions, suggesting that it can sense and appropriately modify its gene expression and metabolism to suit the changing environmental conditions. I am using molecular biological techniques to identify the proteins that are important to this process of sensing and responding of changes in pH. One of the goals of my summer research will be to develop an assay that I can use in conjunction with agrobacterium-mediated mutagenesis to quickly screen for mutants that are unable to maintain the proper acidity of the growth media. I anticipate that these mutants will identify genes that are required for pH modulation and will therefore be interesting candidates for further study.

Secondly, I am looking at the characterization of the distribution of H. capsulatum in the soil of the Ohio-Mississippi River Valley. Although H. capsulatum is endemic to the United States, the distribution of the organism within the environment has not been rigorously quantified. During the summer of 2010, I developed a PCR assay to specifically identify H. capsulatum genomic DNA in the soil. My student and I screened over 120 soil samples, but were unsuccessful in identifying the organism in the environment. I will be going back into the field during this summer, and I will concentrate my efforts in locations that should theoretically be enriched for H. capsulatum (caves and starling roosting sites) Once positive sample are identified, I will then characterize the relative abundance of two specific strains of the organism, North American Type-1, and North American Type-2. I have submitted a leave proposal to learn two new techniques (tRFLP and proteomics) that should be useful in these sorts of environmental assessments.

In addition, I am looking at the identification of alternative hosts for H. capsulatum virulence studies. Although a mouse model of pathogenesis exists for H. capsulatum, studying pathogensis in an animal model is expensive and time consuming. A number of studies have indicated that simple invertebrate organisms such as C. elegans can provide useful model systems for the study of both virulence and the host response to infection.

Also, I am using bioinformatics analysis of the similarities and differences in two sequences strains of H. capsulatum. This research is a collaboration between myself and Sofia Visa (Computer Science). Using a bioinformatics approach, our HHMI funded student Tristan Vrolijk identified the conserved and divergent regions between the genomes of the North American Type 1 and 2 strains of H. capsulatum. This work will continue over the summer of 2010 with two additional students. They will be taking regions of interest and using molecular genetics characterizations of gene expression from these areas of the genome.

Finally, I am looking at the identification of microbial organisms capable of degrading pharmaceutical agents in the environment. This research is a joint collaboration between myself, Melissa Schultz (Chemistry), and Mark Snider (Chemistry). This project will attempt to identify microbial organisms that are able to degrade several of the common pharmaceutical contaminants (antidepressants) in wastewater effuluent.

• BIOL111: Foundations of Biology
• BIOL201: Gateway to Molecular and Cellular Biology
• BIOL335: Microbiology
• BIOL336: Immunology