ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
Filtering by
- All Subjects: Biochemistry
- Creators: Gould, Ian
The PsaA-A684N mutants exhibited increased ET on the B-branch as compared to the A-branch in both in vivo and in vitro conditions. The transient electron paramagnetic resonance (EPR) spectroscopy revealed the formation of increased B-side radical pair (RP) at ambient and cryogenic temperatures. The ultrafast transient absorption spectroscopy and fluorescence decay measurement of the PsaA-A684N and PsaB-A664N showed a slight deceleration of energy trapping. Thus making mutations near ec2 on each branch resulted into modulation of the charge separation process. In the second set of mutants, where ec2 cofactor was target by substitution of PsaA-Asn604 or PsaB-Asn591 to other amino acids, a drop in energy trapping was observed. The quantum yield of CS decreases in Asn to Leu and His mutants on the respective branch. The P700 triplet state was not observed at room and cryogenic temperature for these mutants, nor was a rapid decay of P700+ in the nanosecond timescale, indicating that the mutations do not cause a blockage of electron transfer from the ec3 Chl. Time-resolved fluorescence results showed a decrease in the lifetime of the energy trapping. We interpret this decrease in lifetime as a new channel of excitation energy decay, in which the untrapped energy dissipates as heat through a fast internal conversion process. Thus, a variety of spectroscopic measurements of PSI with point mutations near the ec2 cofactor further support that the ec2 cofactor is involved in energy trapping process.
In the first study, a new chemical approach to functionalize the AFM tip in a simple and user-friendly way has been described. Copper-free click chemistry and a vinyl sulfone PEG linker have been utilized during the process. Using this technique, human thrombin and integrin were detected in separate experiments. Then a novel tri-arm linker with two recognition molecules on it was designed and two proteins (human thrombin and integrin) were detected simultaneously in the same experiment using recognition imaging. This technique can be applied to understand many multivalent interactions taking place in nature. Using the same tri-arm linker functionalized with two biotin molecules, the interaction of streptavidin with mono-biotin and bis-biotin ligands were investigated. The thermal stability of streptavidin-biotin complex was also studied using SDS-PAGE analysis.
In the final study, structure of native chromatin extracted from normal and cancer cell lines were analyzed using AFM imaging and agarose gel electrophoresis. Different salt fractions were used to extract chromatin region depending on their solubility. Mnase sensitivity of the chromatin sample was used to understand the open and closed structures of chromatin from different sources. The amount of chromatin in different salt fractions could act as an indicator of amount of open and condensed chromatin in normal and cancer cells. Eventually this ratio of closed and open structure of chromatin could be an indicator of tumorigenic nature of particular cell lines.
computing, nano-robotics, disease diagnosis, and drug delivery.
This dissertation focuses on developing the structural design rules for "static" DNA nano-architectures with increasing complexity. By using a modular self-assembly method, Archimedean tilings were achieved by association of different DNA motifs with designed arm lengths and inter-tile sticky end interactions. By employing DNA origami method, a new set of design rules was created to allow the scaffolds to travel in arbitrary directions in a designed geometry without local symmetry restrictions. Sophisticated wireframe structures of higher-order complexity were designed and constructed successfully. This dissertation also presents the use of "dynamic" DNA nanotechnology to construct DNA origami nanostructures with programmed reconfigurations.
healthy physiology and disease pathogenesis. The comprehensive profiling of biomolecules in individual cells of a heterogeneous system can provide deep insights into many important biological questions, such as the distinct cellular compositions or regulation of inter- and intracellular signaling pathways of healthy and diseased tissues. With multidimensional molecular imaging of many different biomarkers in patient biopsies, diseases can be accurately diagnosed to guide the selection of the ideal treatment.
As an urgent need to advance single-cell analysis, imaging-based technologies have been developed to detect and quantify multiple DNA, RNA and protein molecules in single cell in situ. Novel fluorescent probes have been designed and synthesized, which targets specifically either their nucleic acid counterpart or protein epitopes. These highly multiplexed imaging-based platforms have the potential to detect and quantify 100 different protein molecules and 1000 different nucleic acids in a single cell.
Using novel fluorescent probes, a large number of biomolecules have been detected and quantified in formalin-fixed paraffin-embedded (FFPE) brain tissue at single-cell resolution. By studying protein expression levels, neuronal heterogeneity has been revealed in distinct subregions of human hippocampus.