published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

The main focus of this thesis is to study the physical characteristics of the N-terminus of human XAF1 protein, a 17kD protein named NTA1, by biophysical methods. Structural studies of the N-terminus of XAF1 serves as a base for the studies of the structure and function relationship of the N-terminus, and the same maybe true for the full length XAF1. Bioinformatics analysis shows that NTA1 shares high sequence identity with the TRAF-type zinc finger domain-containing protein 1 (TRAFD1) and FLN29. Protein structure prediction has been performed on NTA1 by the I-TASSER web server. The prediction result suggests that NTA1 is a structure that consists of α-helices which are joined by flexible linkers. The loose structure shown by I-TASSER is expected to have high solvent accessibility. This coincides with the deuterium exchange data. In addition, by the CD approach, NTA1 was estimated to contain high α-helix content. This result is consistent with the bioinformatics prediction and the secondary structure obtained from the chemical shift index method as well. The physical characterizations of NTA1 showed that NTA1 is a loosely packed protein; and the five zinc ions are bound in the protein structure. Based on the chemical shifts of β-carbons, the Cysteine residues Cys8, Cys11, Cys34, Cys37, Cys50, Cys59, Cys62, Cys86, Cys89 and Cys115 showed a significantly downfield shift, they are probably involved in the zinc ions coordination. The dynamic property of NTA1 was investigated by NMR techniques. Backbone dynamics of NTA1 reveal that NTA1 does not have a typical spherical structure, it is anisotropic. Residues corresponding to the zinc finger regions in the predicted structure show large R2/R1 and S2 values, while regions shown to be flexible linkers in the 3D structure prediction show small R2/R1 and S2 values. Thus, the protein structure homology modeling data are supported by the backbone dynamics data. / published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / abstract / toc / Paediatrics and Adolescent Medicine / Doctoral / Doctor of Philosophy

No description available.

published_or_final_version / abstract / Chemistry / Master / Master of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Microarray expression data which contains the expression levels of a large number of simultaneously observed genes have been used in many scientific research and clinical studies. Due to its high dimensionalities, selecting a small number of genes has shown to be beneficial for many tasks such as building prediction models from the microarray expression data or gene regulatory network discovery. Traditional gene selection methods, however, fail to take the class distribution into the selection process. In biomedical science, it is very common to have microarray expression data which is severely biased with one class of examples (e.g., diseased samples) significantly less than other classes (e.g., normal samples). These sample sets with biased distributions require special attention from researchers for identification of genes responsible for a particular disease. In this thesis, we propose three filtering techniques, Higher Weight ReliefF, ReliefF with Differential Minority Repeat and ReliefF with Balanced Minority Repeat to identify genes responsible for fatal diseases from biased microarray expression data. Our solutions are evaluated on five well-known microarray datasets, Colon, Central Nervous System, DLBCL Tumor, Lymphoma and ECML Pancreas. Experimental comparisons with the traditional ReliefF filtering method demonstrate the effectiveness of the proposed methods in selecting informative genes from microarray expression data with biased sample distributions. / by Abu Hena Mustafa Kamal. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Cancer is the second leading cause of death in the western world. In order to treat various types of cancer, platinum-based drugs are most widely employed as metal-containing chemotherapeutic agents. However, their clinical usage is hindered by toxic side effects, and by the emergence of drug resistance. Our focus was to replace platinum with less toxic metal like tin which can give better alternatives for cancer treatment. The major aim of our study was to synthesize novel organotin polyethers (Sn-O) which can be used to combat cancer. Preliminary results from our laboratory using organotin polyethers, that were synthesized by varying the structure of diols showed growth inhibition in Balb-3T3 cells. This study directly led us to hypothesize the two structural windows, first by changing the distance between diol and second, by presence of unsaturation in diols, the biological activity of organotin polyethers (Sn-O) can be enhanced significantly. Different series of polymeric compounds were synthesized based upon these two structural windows and the formation of products was validated using standard techniques like infrared spectroscopy (IR), light scattering photometer, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and nuclear magnetic resonance (NMR). The synthesized polymers arrested the growth of cancer cell lines including bone, prostate, colon, breast, pancreas and lung cancer derived cell lines in vitro. In number of instances where chemotherapeutic index values of two and greater were found that these polymers are significantly more active against cancer cells than non-cancerous cells in culture. / These results support the starting premise that the polymers may exhibit cancer cell selectivity. In general, it was found that the presence of unsaturation increased the probability that the polyether would inhibit the growth of various cancer cell lines. Further, in some cases, polyethers with short distances between the oxygen atoms showed a superior ability to inhibit the growth of various cancer cell lines in comparison to those with longer distances between the oxygen atoms. These results provide a framework for the discovery of novel cancer therapeutics. / by Girish Vallabhbhai Barot. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Mak, Keng Hou. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 77-91). / Abstracts in English and Chinese. / Thesis Committee --- p.2 / Declaration --- p.3 / Table of Contents --- p.4 / List of Abbreviations --- p.6 / List of Figures --- p.8 / Abstract --- p.10 / Chapter Chapter 1 --- Introduction --- p.12 / Chapter 1.1 --- Background --- p.12 / Chapter 1.1.1 --- Overview of apoptosis --- p.12 / Chapter 1.1.2 --- Synopsis of the apoptotic pathway --- p.13 / Chapter 1.1.3 --- Defining apoptosis --- p.14 / Chapter 1.1.4 --- Interaction between pro- and anti-apoptotic factors determines cell fate --- p.14 / Chapter 1.1.5 --- DNA fragmentation during the execution phase --- p.15 / Chapter 1.1.6 --- Current understanding of the point of commitment in apoptosis --- p.16 / Chapter 1.1.7 --- Previous studies and hypotheses related to the reversibility of late-state apoptosis --- p.16 / Chapter 1.1.8 --- Unanswered questions --- p.19 / Chapter 1.2 --- "Hypothesis and objectives, Study models and Significance" --- p.19 / Chapter 1.2.1 --- Hypothesis and objectives --- p.19 / Chapter 1.2.2 --- Study models --- p.20 / Chapter 1.2.3 --- Significance --- p.20 / Chapter Chapter 2 --- Materials and Methods --- p.22 / Chapter Chapter 3 --- Results --- p.30 / Chapter 3.1 --- Dying cells reversed execution stage of apoptosis after removal of apoptotic stimuli --- p.30 / Chapter 3.2 --- Dying cells reversed apoptosis after DNA damage --- p.37 / Chapter 3.3 --- Genetic alterations and transformation occurred after reversal of apoptosis --- p.43 / Chapter 3.4 --- Investigating molecular mechanism driving reversal of apoptosis --- p.50 / Chapter 3.4.1 --- Preparation and characterization of samples for microarray --- p.50 / Chapter 3.4.2 --- Gene ontology enrichment analysis of the expression profile during reversal of apoptosis --- p.52 / Chapter 3.4.3 --- Interfering stress response or anti-apoptotic factors during the reversal of apoptosis drove cells to terminal death --- p.56 / Chapter Chapter 4 --- Discussion --- p.62 / Chapter 4.1 --- "Reversal of apoptosis in ""normal cells"" was observed" --- p.62 / Chapter 4.2 --- Cells surviving apoptosis had their genomes damaged and altered --- p.63 / Chapter 4.3 --- Transformation occurred after reversal of apoptosis --- p.65 / Chapter 4.4 --- Investigating molecular mechanism driving reversal of apoptosis --- p.65 / Chapter 4.5 --- Summary --- p.68 / Chapter Chapter 5 --- Perspectives --- p.70 / Chapter 5.1 --- Could reversal of apoptosis be evolutionarily advantageous? --- p.70 / Chapter 5.2 --- "Reversal of apoptosis as an ""individualistic"" behavior against organismal integrity" --- p.71 / Chapter 5.3 --- Proposed studies --- p.72 / Chapter 5.3.1 --- Other apoptotic targets that may leave persistent effects --- p.72 / Chapter 5.3.2 --- Post- caspase activation regulation of apoptosis --- p.74 / Chapter 5.3.3 --- Identifying correlation between reversal of apoptosis and cancer --- p.74 / Chapter 5.3.4 --- Single cell methods and cell tracking system for further studies --- p.75 / Chapter 5.3.5 --- Notes on studying reversal of apoptosis in relation to phagocytosis --- p.76 / References --- p.77

Prostate cancer is the most common form of non-skin cancer and the second leading cause of cancer deaths within the United States. The five year survival rate has increased from 69% to 99% over the last 25 years for the local and regional disease, but has remained fairly low (approximately 34%) for the advanced disease. Therefore, current research is aimed at finding complementary or alternative treatments that will specifically target components of the signal transduction, cell-cycle and apoptosis pathways to induce cell death, with little or no toxic side effects to the patient. In this study we investigated the effect of genistein on expression levels of genes involved in these pathways. Genistein is a (4 , 5 , 7-trihydroxyisoflavone) is a major isoflavone constituent of soy that has been shown to inhibit growth proliferation and induce apoptosis in cancer cells. The mechanism of genistein-induced cell death and potential molecular targets for genistein in LNCaP prostate cancer c ells was investigated using several techniques. The chemosensitivity of genistein towards the prostate cancer cells was investigated using the ATP and MTS assays and apoptosis induction was determined using apoptosis and caspase assays. Several molecular targets were also identified using cDNA microarray and RT-PCR analysis. Our results revealed that genistein induces cell death in a time and dose-dependent manner and regulates expression levels of several genes involved in carcinogenesis and immunogenicity. Several cell cycle genes were down-regulated, including the mitotic kinesins, cyclins and cyclin dependent kinases, indicating that genistein is able to halt cell cycle progression through the regulation of genes involved in this process. / Several members of the Bcl-2 family which are involved in apoptosis were also affected and a number of genes involved in immunogenicity were up-regulated including the DefB1 and HLA membrane receptors. The results of this study provide evidence of genistein's ability to inhibit growth proliferation and induce apoptosis and indicates its potential as an adjuvant in chemotherapy and immunotherapy. / by Kendra Merchant. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.