Thesis (M.A.)--University of Delaware, 2009. / Principal faculty advisor: Stephen Mortenson, Dept. of Communcation. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 135-144). Available also in a digital version from Dissertation Abstracts.

No description available.

This study was focused on the promoter and non-coding regions of the ribosomal RNA (rrn) operon(s) of mycobacteria; namely, the leader and the intergenic spacer regions. Two clones containing the promoter sequences of M .leprae and M. tuberculosis rrn operon were sequenced, their promoter elements were identified by primer extension experiments and by comparison with E.coli consensus promoter sequences. Their function was tested in E.coli and M. smegma tis . The sequences of the leader and intergenic spacer regions from eight and six species respectively were established after amplification by means of peR. Both leader and spacer regions contain antitermination elements and RNaseIII processing sites. The sequences established for these two regions also showed greater variability than the 168 rRNA gene and are suitable for phylogenetic studies. The sequences of the two rrn operons of M.smegmatis upstream from the 168 rRNA gene were cloned and sequenced. Their sequences showed that rrnI has a Box B element which is typical of slow-growers and that rrnII does not. Primer extension studies revealed that the rrn operon of slow-growers has a single promoter. In contrast multiple promoters were identified in the faster-growing M.smegmatis. Distinctive features, which are absent from slow-growers, were identified in the intergenic spacer regions of M.smegmatis.

Background: Excess plugging of small airways is associated with premature death in chronic obstructive pulmonary disease (COPD). Over-expression of beta-epithelial sodium channel (β-ENaC) in airway epithelia in mice resulted in plugging of small airways while cystic fibrosis transmembrane regulator (CFTR) negatively regulated ENaC activity in cell models. Purpose: To test the hypothesis that accumulation of mucus exudates observed with the progression of COPD is related to excess airway epithelial sodium re-absorption as a result of over-expression of β-ENaC and reduced expression of CFTR by small airway epithelia. Methods: Small airway epithelial samples from frozen lungs from patients at different levels of COPD severity were isolated by laser capture microdissection (LCM). β-ENaC, CFTR, and β-actin (control) gene expression was determined by qRT-PCR and compared to expression in entire airways and lung parenchyma surrounding these airways. β-ENaC protein as well as epithelial mucin expression and mucus plugging were localized and quantified after immunohistochemical and periodic acid Schiff staining, respectively. Results: β-ENaC mRNA expression had a strong positive correlation with that of CFTR (p<O.0001) in airway epithelia and surrounding lung parenchyma (p=O.Ol) but not whole airways. β-ENaC mRNA and protein expression were positively correlated (p=O.4O, p=O.O5) and protein expression significantly increased with GOLD stage of COPD severity. Epithelial mucin expression positively correlated with β-ENaC (p=O.38, p=O.O5) and CFTR (p=OAO, p=O.O4.) mRNA and with mucus plugging (p=O. 43 , ptO.OOO2). CFTR mRNA also correlated positively with mucus plugging (p=O. 48 , p=O.O2). Conclusions: Strong positive correlations between β-ENaC and CFTR mRNA expression that are limited to the lung parenchyma and epithelium suggest a novel mechanism of mRNA regulation. This differs from their functional relationship where an inverse relationship between CFTR expression and β-ENaC activity has been reported. Positive correlations of epithelial mucin or mucus plugging with CFTR mRNA but not β-ENaC protein expression in the small airway epithelium suggest that CFTR may regulate mucin at this site independently of β-ENaC protein. The relationship between β-ENaC mRNA andepithelial mucin expression could be due to strong correlations between β-ENaC and CFTR mRNA expression but β-ENaC’s relationship with COPD GOLD stage suggests it may nevertheless play a role in COPD. / Medicine, Faculty of / Medicine, Department of / Experimental Medicine, Division of / Graduate

DNA microarray technology has been extensively utilized in the biomedical field, becoming a standard in identifying gene expression signatures for disease diagnosis/prognosis and pharmaceutical practices. Although cancer research has benefited from this technology, challenges such as large-scale data size, few replicates and complex heterogeneous data types remain; thus the biomarkers identified by various studies have a small proportion of overlap because of molecular heterogeneity. However, it is desirable in cancer research to consider robust and consistent biomarkers for drug development as well as diagnosis/prognosis. Although cancer is a highly heterogeneous disease, some mechanism common to developing cancers is believed to exist; integrating datasets from multiple experiments increases the accuracy of predictions because increasing the sample size improves and enhances biomarkers detection. Therefore, integrative study is required for compiling multiple cancer data sets when searching for the common mechanism leading to cancers. Some critical challenges of integration analysis remain despite many successful methods introduced. Few is able to work on data sets with different dimensionalities. More seriously, when the replicate number is small, most existing algorithms cannot deliver robust predictions through an integrative study. In fact, as modern high-throughput technology matures to provide increasingly precise data, and with well-designed experiments, variance across replicates is believed to be small for us to consider a mean pattern model. This model assumes that all the genes (or metabolites, proteins or DNA copies) are random samples of a hidden (mean pattern) model. The study implements this model using a hierarchical modelling structure. As the primary component of the system, a multi-scale Gaussian (MSG) model, designed to identify robust differentially-expressed genes to be integrated, was developed for predicting differentially expressed genes from microarray expression data of small replicate numbers. To assure the validity of the mean pattern hypothesis, a bimodality detection method that was a revision of the Bimodality index was proposed.

No abstract available / Dissertation (LLM)--University of Pretoria, 2014. / lmchunu2014 / Private Law / unrestricted

No description available.

Bacterial polyketides possess an enormous range of chemical diversity and biological function. Many polyketides such as tetracycline, epothilone, and rapamycin have been developed into key clinical pharmaceuticals in a broad range of therapeutic areas. Sequencing of bacterial genomes has shown that there are many more polyketide biosynthetic pathways than there are polyketides isolated from standard cultivation techniques. These genetically encoded polyketide natural products from cultivatable and uncultivatable bacteria represent one of the greatest remaining untapped reservoirs of new natural product diversity. To access this untapped diversity of polyketide products, a general method for heterologous expression of these pathways is needed. Heterologous expression has proven to be a valuable asset in the discovery, production, engineering, and characterization of bacterial secondary metabolites and the complex enzymology involved in their biosynthesis. Herein we discuss the development and investigation of two unique heterologous expression platforms utilizing host strains of Myxococcus xanthus and Escherichia coli. Using our developed heterologous hosts, we were able to produce the Streptomyces rimosus polyketide oxytetracycline. Through production of oxytetracycline in E .coli we have identified the potential of alternative transcription factors as regulators of secondary metabolism. Further investigation and development of alternative transcription factors as regulators of secondary metabolism in heterologous hosts could benefit the development of robust general methodology for the heterologous expression of polyketides.

Client emotional expression in session is valuable as it promotes clients’ sense of agency, increases their capacity for introspection, and is linked to decreases in depressive symptoms. By extension, understanding counsellors’ responses to client emotional expression is relevant. In the current study, retrospective accounts of self-reported securely-attached novice counsellors were collected for the purpose of exploring how they responded to client emotional expression. To obtain meaningful and descriptive accounts of the data, a thematic analysis (Braun & Clarke, 2006) was used as the research methodology. Resultant themes showed that novice counsellors reported experiencing their own covert and overt emotional reactions in response to clients’ emotional expression. They also reported struggling with the decision to use their preferred response. The results provided insights into how the task of responding to client emotion was complex for novice counsellors. Analyses and understanding of these results have potential developmental and educational implications.