Matching Items (2)
Description
Arsenic contamination in groundwater is a serious problem both in local Arizonan communities and abroad: prolonged exposure to arsenic contamination can cause cancer, vascular damage, and liver failure. This project aims to engineer the microalgae Chlamydomonas reinhardtii to sequester arsenic out of water. Metallothionein, arsenate reductase, and ferritin were integrated into the microalgae via the pASapI plasmid. The plasmid rescues function of the photosystem II gene, leveraging the ability to photosynthesize as a selective trait. Metallothionein and ferritin bind the two most common forms of arsenic: arsenite and arsenate, respectively. Arsenate reductase catalyzes the reduction of arsenate to arsenite, allowing for the ultimate sequestration of the toxic metal to occur in the chloroplast. The algae was transformed using a biolistic device, to create three mutant strains, expressing Metallothionein (MT), Arsenate Reductase (ArsC)-HA, and MT-6xHIS plasmids respectively. When testing the fluorescence output of these three strains, they showed a maximum quantum yield of photosystem II comparable to that of the wildtype algae, indicating that the rescue gene had been incorporated into the chloroplast genome properly. Strains were exposed to arsenic-containing media at 50ppb and 500 ppb for 48 and 72 hours to determine the arsenic sequestration rate. Arsenic concentration in the supernatant was measured using ICP-MS analysis and sequestration rate was calculated in terms of arsenic concentration per fold growth of algae. The normalized arsenic sequestration rates of tagged protein expressing strains at 50 ppb were significantly higher than wildtype.
ContributorsLieberman, Emma (Author) / Bartelle, Benjamin (Thesis director) / Redding, Kevin (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2022-05
Description
Characterizing and identifying neuroinflammatory states is crucial in developing treatments for neurodegenerative diseases. Microglia, the resident immune cells of the brain, regulate inflammation and play a vital role in maintaining brain health by producing cytokines, performing phagocytosis, and inducing or reducing inflammation. These functional states can be described by specific patterns of gene expression called transcriptional programs, which are determined by the activity of a set of key transcription factors that have mostly been identified. Thus, an assay for transcription factor activity could reveal the state of the microglial cells and neuroinflammation across the brain. This research developed an assay that uses a transcription factor dependent reporter to indicate which transcriptional programs are activated in the cell when exposed to different stimuli. The prototype assay quantifies nuclear factor kappa B (NF-kB) response in cultured human cells. NF-kB is a well-characterized transcription factor associated with inflammatory pathways in most cells, including microglia. The reporter construct contains an NF-kB specific responsive element that can induce fluorescence/luminescence upon activation of the transcription factor. In an iterative refinement, a dual response fluorescent reporter was developed, which uses a secondary constitutively fluorescent reporter for built-in normalization of the responsive element for microscopy studies. With further refinement, this modular system will serve as a template for less understood transcriptional enhancers allowing for rapid, low-cost assays of neuroimmune regulators and potential in vivo applications in the study of neuroinflammation.
ContributorsLieberman, Emma (Author) / Bartelle, Benjamin B (Thesis advisor) / Plaisier, Christopher L (Committee member) / Andrews, Madeline G (Committee member) / Arizona State University (Publisher)
Created2023