Beaver dams can function as natural filters helping decrease pollution in streams, creeks, and rivers. Beaver dams slow down the water flow in a creek or river, forming ponds that help trap excessive nutrients. An excess of nutrients such as phosphate and nitrate can cause eutrophication, leading to increased algal blooms that can produce toxins and ultimately deplete oxygen in the water. This study investigates the ion levels of chloride, fluoride, phosphate, nitrate, sulfate, and bromide upstream and downstream of the major beaver dam at Pipers Creek in North Seattle's Carkeek Park over the course of a year to better understand the long-term impacts of the dam. We collected three water samples at each of eleven sites along the creek, eight upstream from the dam, and three downstream. Ion chromatography was used to measure the concentrations of anions at each site. The results of this study help elucidate the role of beavers in moderating water quality and provide important baseline data documenting seasonal variations in the nutrient load at Pipers Creek. These findings can also be used to better understand the impact of new beaver dams in other freshwater systems.

The formation of the neural tube is a critical event in embryonic development. Morphogenic signals guide a layer of embryonic cells to fold and create the neural tube, which serves as the precursor to the brain and spinal cord. When the neural tube fails to close properly, neural tube defects arise. Spina bifida is the most common neural tube defect, affecting 1 in 1,000 births. Although surgical procedures can be used to treat it, they often result in complications involving serious disabilities and infections. While neural tube defects are believed to have a multifactorial etiology, which includes a genetic component, proposed causative mutations that lead to the development of spina bifida in humans have yet to be thoroughly examined. Recently, mutations in the gene for a G-protein coupled receptor known as GPR161 were identified in infants with spina bifida. However, the role of GPR161 variants in the development of spina bifida is not fully understood. Utilizing CRISPR/Cas9 technology in human induced pluripotent stem cells, I have generated GPR161 knockout and point mutation lines and differentiated them into neural progenitors in a 2D model while also developing a 3D organoid system. Using these models, I will investigate the downstream pathways involved in the formation and patterning of the neural tube that could be influenced by the mutations. This includes the sonic hedgehog pathway, Wnt pathway, and assessing neural differentiation markers. I will evaluate these markers through various assays, including immunofluorescence and real-time quantitative PCR. Through these efforts, we will enhance our understanding of a genetic component in the etiology of spina bifida while demonstrating the value that induced pluripotent stem cells can have in studying human development and treating human diseases by recapitulating them in human models in vitro.

In our biochemistry teaching labs, students conduct 10-week projects using recombinant protein expression and purification protocols, adapted from Fred Hutch, distributed and tracked via GENI-ACT.org, to identify immunoproteins of research or biomedical interest. We hypothesize they can produce antigen fragments for antibody studies and siderocalin proteins, which bind bacterial siderophores, yielding different amounts and results. In Winter 2023, students modeled antibody fragments with I-TASSER, expressed top constructs with His-tags, and purified them using Ni-NTA resin. In Winter and Fall 2024, siderocalins were expressed as GST-tagged constructs in BL21 and DH5alpha cells using longer expression. The human siderocalin in DH5alpha formed an orange solution, consistent with known siderocalin-enterobactin-Fe complexes. Unexpectedly, other species’ siderocalins appeared yellow, pink, or blue, suggesting functional diversity. Students produced enough immunoproteins for viability tests and are now expressing homologs of the blue siderocalin. They participated in all stages, developing spectroscopy and protein crystallization skills for research careers.

Caffeine is one of the most widely consumed stimulants globally, yet its effects on explicit memory remain an area of active research. This literature review examines how caffeine influences explicit memory, particularly in short-term recall and recognition memory in young adults ages 18-22. By synthesizing findings from recent peer-reviewed studies, we explore the neurochemical mechanisms, focusing on caffeine’s role in modulating adenosine receptors, enhancing neuronal activity, and affecting hippocampal-dependent memory functions. Some studies indicate that caffeine improves attention and alertness, which can indirectly support memory formation. However, other studies suggest that excessive intake or habitual use may lead to adverse effects, particularly if it disrupts sleep patterns or increases anxiety—both of which are known to impair memory. These conflicting findings highlight the complexity of caffeine’s effects and the challenge of drawing definitive conclusions. Beyond individual consumption patterns, methodological differences across studies like varying dosage intake and testing periods also contribute to conflicting findings. Variations in participant characteristics, experimental designs, and memory assessment methods make direct comparisons across studies challenging. Some studies focus on immediate recall, while others examine delayed retrieval or recognition memory, further adding to the variability in reported outcomes. By critically evaluating existing research, we aim to clarify the relationship between caffeine and explicit memory while identifying research gaps that future studies should address. Given the widespread use of caffeine among young adults, particularly for academic performance, a deeper understanding of its cognitive effects is essential. Investigating how caffeine influences memory under different conditions—such as varying levels of stress or sleep deprivation—could provide valuable insights. Future research should also refine methodologies to isolate caffeine’s specific effects on explicit memory in young adults.