Premature birth interrupts the typical development of the human fetus, leaving the infant born with underdeveloped gastrointestinal and immune systems. Preterm infants have reduced stomach acidity, reduced digestive protease activity, more permeable intestinal membranes, impaired innate and adaptive immune response, and poor microbiome development. Due to these factors, preterm infants...
The myxozoan parasite Ceratonova shasta threatens both juvenile and adult salmonid populations in the Pacific Northwest region of the United States, causing intestine necrosis and hemorrhaging, along with high mortality in some fish strains. It induces an inflammatory tissue response in susceptible strains of fish; understanding the interactions between C....
With an ever-growing urban population there is a continued interest in urban agriculture as a viable option to improve access to fresh produce and enhance food security in an increasingly urbanized world. As the primary method of urban agriculture in the United States, community gardens also provide a range of...
All mammals host communities of commensal microbes in and on their bodies. Recent technological advances, combined with experimental studies in laboratory animals, are beginning to reveal the ubiquitous links between the gut microbiome and host disease, metabolism, immunity, and numerous other host functions. A new challenge of microbiome research is...
Juvenile Chinook Salmon (Oncorhynchus tshawytscha) have a finite amount of energy that they can use to move from their riverine habitat to their oceanic habitat. Fish in the Willamette River Basin are prevented from moving to the ocean easily by dams which create reservoirs, where they reside for up to...
Parasitic infections and immune challenges can affect host reproductive fitness and, ultimately, the evolution of host populations in a myriad of ways. The fitness implications of parasitic infections range from increased host mortality to subtle changes in reproductive investment. From alterations of behaviors, sexual signaling, and competitive ability to changes...
Disease acts as a powerful selective force in natural systems, driving the rapid evolution of resistance in the host. In the face of a myriad of pathogenic challenges in natural systems, hosts must balance the energetic needs of maintenance and reproduction with costly resistance mechanisms. In this dissertation I will...
Chlamydia is a genus of obligate intracellular bacteria that undergo a unique, biphasic developmental cycle. The infectious and metabolically inert Elementary Bodies (EBs) begin the cycle of infection by attaching and invading a host cells. Once inside, the EBs differentiate into the metabolically active, dividing Reticulate Bodies (RBs) within their...
The chlamydiae are a family of obligate intracellular bacteria that have a unique bi-phasic developmental cycle, unique cellular properties, and a unique set of challenges to studying its biology. While genetic manipulation is becoming routine in Chlamydia, there are significant challenges to working with this intracellular parasite. The body of...
Because of its attractive material properties like high hardness, high toughness, and excellent high temperature strength, materials like silicon nitride are becoming more common for use in high performance applications. However, there have been limited studies of the fatigue behavior of small cracks in silicon nitride and other materials toughened...