DISSERTATION RESEARCH: From Metabolites to Continent: Host-parasite Interaction across Spatio-temporal Scales

All living organisms interact with parasites. Often, the outcome of these interactions is either morbidity or the death of the host. However, in some instances, the behavior of the host can be manipulated by the parasite. This behavioral manipulation increases the transmission of the parasite, either to a new environment crucial for its development, or to a new host. Although many examples of parasitic behavioral manipulation exist, little is known of the mechanisms underlying it. Investigators will study the genetic basis of parasitic manipulation by analyzing the gene expression of host brains at the exact moment they are being manipulated. Because the parasite that manipulates the behavior also results in host sickness, the investigators will use a non-manipulative parasite as a comparison. Thus, they will be able to distinguish between the genetic basis of sickness and manipulation. Since many manipulators exploit immune systems and neural connections, understanding how they manipulate their host has practical and theoretical applications, leading us to better understand sickness behavior and mental disorders. Brain snatchers are very popular among the general public, including K-12, as they turn their host into 'zombies.' Investigators will leverage this popularity to bring science to K-12 classrooms and local communities.

Investigators will study the proximate mechanisms of parasitic behavioral manipulation, by studying gene expression of the host during the moment of behavioral manipulation. Because the manipulative parasite also causes sickness, and the manipulation is immediately followed by death, a generalist non-manipulative parasite that also results in sickness and death of the host will be used as control. Healthy, uninfected, host brains will be used as a baseline for normal gene expression. Investigators will use Illumina HiSeq 2500 technology to compare the transcriptome of manipulated host brains with those that present general sickness and death symptoms. This will allow the research team to capture the genes that are differentially expressed during manipulation and are not related to general sickness or death processes. Understanding the gene expression of a manipulated host is a fundamental step to understand the mechanisms underlying behavioral manipulation by parasites. Additionally, the data will be interpreted in an interdisciplinary broader context, together with other approaches (different ecological scales) employed by the same research group to fully understand the parasitic manipulation. Results of this project will be published in peer-reviewed journals and also presented at conferences. All data from this project will be hosted on public databases such as Genbank and Dryad as well as stored on Penn State's publically accessible databases.