Huntington’s disease (HD) is caused by the expansion of a CAG repeats encoding polyglutamine (polyQ) in the first exon of Huntingtin (Htt) gene. In HD patients, polyQ contains 36-183 glutamine residues, whereas normal individuals have a polyQ of only 8-35 residues. To elucidate this threshold phenomenon of polyQ aggregation, fluorescence proteins CFP and YFP were attached to both ends of polyQ of different lengths. FRET (fluorescence resonance energy transfer) was conducted to characterize the conformation of polyQ in the pre-aggregation state. Our FRET data show that both the normal and expanded polyQ tracts reveal the same extended structure in low concentration. Longer polyQ has multiple cooperative binding sites with higher avidity. PolyQ tracts form aggregates when proteins exceed a critical concentration. The antibody MW1 Fv fragment binds to polyQ, breaks apart polyQ oligomer and stabilizes it in a more extended conformation. The addition of polyproline to the C-terminus inhibits polyQ aggregation by inducing PPII-like Helix structure. To understand how the flanking sequence affects the polyQ structure, the structure of Q10P10 peptide in complex with MW1 Fv was determined by protein crystallography and compared with Q10/Fv crystal structure. Q10P10 peptide bound to Fv has a similar extended structure as Q10 peptide when a polyproline tract adopts PPII helical structure sticking out of the complex. Toll-like receptors are transmembrane receptors on different kinds of leukocytes. They can recognize the structural conserved molecular motifs derived from microbes. On the upstream of the TLR signal pathway, TLRs recruit the adaptor protein-MyD88 through TIR/TIR domain interaction, and MyD88 recruits the downstream kinases IRAK4 and IRAK1 through death domain/death domain interaction. Pellino1, a newly identified E3 ubiquitin ligase, is also involved in TLR signaling by adding polyubiquitin chain to IRAK1 in conjugation with Ubc13/Uev1a E2 complex. TIR/TIR and DD/DD binding motifs were studied with techniques including mutagenesis, analytical gel filtration, NMR spectroscopy and crystallography. We identified a MyD88DD (E52QR62S) double-mutant that attenuates protein aggregation without interrupting the binding with IRAK4. This double mutant is a good candidate for structure determination by NMR spectroscopy. Our ubiquitination assay showed Pellino1 catalyzes polyubiquitination in the presence of Ubc13/Uev1a in vitro. Needle cluster-shaped crystals of Pellino1/Ubc13/ Uev1a protein complex were obtained by “hanging drop” method of vapor diffusion. Once the crystallization conditions are optimized, we will be able to collect X-ray diffraction data for this E2/E3 complex.

States are increasingly using toll roads as a means of financing transportation capital needs as well as expanding transportation system capacity. Whether toll roads can attract trucks partially determines the performance of the investment. Unfortunately, the low profit margin in the trucking industry and the relatively high tolls truckers pay leads to their reluctance to use toll facilities. Incentives for truck use of a toll road, State Highway 130 (SH 130) near Austin, Texas, were analyzed in this research. As a parallel toll road to the non-tolled, congested facility Interstate 35 (I-35), SH 130 was projected to carry a lot of traffic, including a significant proportion of trucks. In order to make this tolled facility more attractive to trucks, innovative incentives were considered. The potential truck demand for SH 130 and their potential reactions to the incentives were estimated in this research based on survey data. According to survey responses, different groups of the trucking industry had very different characteristics. Due to the variation of the characteristics among different categories of trucks, truckers’ travel behavior and incentive preference were also different by trucking group. Compared with other groups of truckers, smaller companies (owner-operators) were the least likely to use SH 130, while private carriers were the most likely to use SH 130. It was also found many truckers had already made adjustments both to their time and route to avoid traveling in congested conditions. Among all the categories of truckers, for-hire truckers had the least flexibility. The average value of travel time savings of trucks around the Austin area was $44.20 per hour. As the price of travel time savings went up, the percentage of truckers using SH 130 decreased. Price-related incentives were discovered to be most popular with truckers. Among all of the price-related incentives, off-peak discounts and a free trip after a number of paid trips were the most popular incentives.

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TLRs play a key role in initiating innate immunity and in regulating the nature of the adaptive immune response. We hypothesized that functional responsiveness to TLR stimulation differs in clinically; environmentally; ethnically distinct pediatric populations. PBMC obtained from 272 children were stimulated with a panel of TLR ligands. Levels of pro- and anti-inflammatory, Th1-, Th2-associated cytokines were quantified by ELISA. We demonstrate that use of threshold concentrations of TLR4 and TLR2 ligands reveal striking differences in cytokine responses between asthmatic and non-atopic children. Specifically, non-atopic controls produce higher levels of pro-inflammatory cytokines, whereas asthmatics exhibit increased anti-inflammatory IL-10 responses. Asthmatic children exposed to environmental tobacco smoke (ETS) demonstrated elevated levels of chemokines relative to non-ETS exposed asthmatics and controls. First Nation children favor anti-inflammatory IL-10 responses, whereas Caucasian population respond to TLR activation by production of more robust pro-inflammatory and Th1 biased cytokine and chemokine responses.

TLRs play a key role in initiating innate immunity and in regulating the nature of the adaptive immune response. We hypothesized that functional responsiveness to TLR stimulation differs in clinically; environmentally; ethnically distinct pediatric populations. PBMC obtained from 272 children were stimulated with a panel of TLR ligands. Levels of pro- and anti-inflammatory, Th1-, Th2-associated cytokines were quantified by ELISA. We demonstrate that use of threshold concentrations of TLR4 and TLR2 ligands reveal striking differences in cytokine responses between asthmatic and non-atopic children. Specifically, non-atopic controls produce higher levels of pro-inflammatory cytokines, whereas asthmatics exhibit increased anti-inflammatory IL-10 responses. Asthmatic children exposed to environmental tobacco smoke (ETS) demonstrated elevated levels of chemokines relative to non-ETS exposed asthmatics and controls. First Nation children favor anti-inflammatory IL-10 responses, whereas Caucasian population respond to TLR activation by production of more robust pro-inflammatory and Th1 biased cytokine and chemokine responses.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Akademisk avhandlung--Göteborgs högskola. / "Rättelser till personregistret": slip inserted. "Källor och litteratur": p. [xii]-xxi.

Tübingen, Univ., Diss., 2007.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 408-415). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.