Thesis (Ph. D.)--Georgia State University, 2008. / Title from title page (Digital Archive@GSU, viewed July 1, 2010) Jenny J. Yang, committee chair; Edward Brown, Giovanni Gadda, Zhi-ren Liu, committee members. Includes bibliographical references (p. 230-258).

Thesis (Ph.D.)--University of California, San Francisco, 2004. / Includes bibliographical references. Also available online.

Thesis (Ph.D.)--University of California, San Francisco, 2004. / Includes bibliographical references. Also available online.

Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract. Includes bibliographical references (leaves 106-114).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 148-166).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 104-120).

Thesis (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2014 (Department of Endodontics). / Includes bibliographic references: leaves 41-49. / Sjogren's syndrome (SS) is a chronic, multisystem inflammatory disorder of multifactorial etiology resulting in loss of secretory function in the exocrine glands including salivary and lacrimal. Even though the pathophysiology progression of SS has been subject to great amount of research, the roles of different mechanisms remain inconclusive. The main dogma is that immune system pathology drives SS; however, there is no straightforward pathogenesis theory as there are multiple autoantibodies and changing proportions of different T-cell subsets with the progression of the disease along with many other different contributors. Interestingly, increasing evidence points to structural defects, including defective E-cadherin adhesion, to be involved in the etiology of SS. Recently, the Hippo signaling pathway has emerged as one of the main pathways regulating size of the organs and proliferation/ differentiation of cells, in part via interaction with E-cadherin junctions. Despite this, the role of Hippo signaling in the ... [TRUNCATED]

Plasmodium spp. and Trypanosoma brucei spp. are protozoan parasites with complex lifecycles, each having to adapt to the diverse environments of their insect vector and mammalian host. Each has multiple developmental forms that differ in their morphology and metabolism. Differentiation between these forms is a tightly regulated and often synchronised process in response to changes in the parasite's environment. The molecular mechanisms by which they perceive and respond to such environmental changes are largely unknown. The Plasmodium and T. brucei genomes encode a homologue of the phylogenetically widespread GPR89 family of putative receptors or channels. The mammalian GPR89 homologue has been implicated in the regulation of Golgo acidification, whilst in plants it has been shown to be involved in G protein signally pathways. This study set out to characterise the Plasmodium and T. brucei GPR89 proteins in order to assess their potential role as environmental sensors. Bioinformatic analyses demonstrated that the GPR89 proteins are a highly divergent family of multi-transmembrane domain proteins that may perform a channel or transporter function. Several expression strategies were employed to evaluate the role of the GPR89 proteins. Functional insight was gained from the ectopic expression of both the T. brucei and Arabidopsis thaliana GPR89 proteins in T. Brucei cells. Over-expression of TbGPR98 causes premature stumpy formation in pleomorphic T. brucei cells. This phenotype was replicated by over-expression of a A. thaliana homologue in T. brucei despite signigicatnt sequence divergence. Furthermore, both were demonstrated to act on the same pathway as the putatuve RNA binding protein, RBP7 that was receontly identified in a genome-wide screen for components of the stumpy differentiation pathway. Hence, TbGPR89 is likely a compnent of the slender to stumpy differentiation pathway in bloodstream form trypanosomes and there appears to be functional complementarity between T. brucei and A. thaliana GPR89 proteins.

Magister Scientiae - MSc / Plants in the field are exposed to multiple stresses and their response to these various stresses determines their capacity to survive. Plants can use multiple signaling pathways and signals to mediate their response; for example, at least four different signal pathways have been identified for water-deficit stress (Shinozaki and Yamaguchi-Shinozaki, 1997; Xiong et al., 2002). Different forms of stress may activate or utilize the same components, including proteins and other signaling molecules. Signaling molecules such as jasmonic acid (JA) are involved in multiple stress response and development in plants (Creelman and Mullet, 1995, 1997; Turner et al., 2002). However it is the specific combination of various components of the signaling network coupled with spatial and temporal factors that allows the plant to mount a directed response to any given stress factors. Systemic defense responses thus provide an attractive model for the study of cell-to-to cell signal transduction pathways that operates over long distances (Lucas and Lee, 2004). Cellular and physiological evidence suggest the presence of a novel class of systemic mobile plant molecule that is recognized by antibodies against vertebrate atrial natriuretic peptides (ANPs). It has been demonstrated that a recombinant Arabidopsis thaliana natriuretic peptide analogue (AtPNP-A) molecule can induce osmoticumdependent water uptake into protoplast at nanomolar concentrations thus affecting cell volume and hence plant growth. In this study we confirm that active recombinant protein causes swelling in Arabidopsis mesophyll cell protoplasts (MCPs). / South Africa

Following starvation, Dictyostelium discoideum cells aggregate, a response that requires chemotaxis to cyclic AMP (cAMP) and the relay of the cAMP signal by the activation of adenylyl cyclase (ACA). Insertional inactivation of the rasG gene resulted in delayed aggregation and a partial inhibition of early gene expression, suggesting that RasG does have a role in early development. When the responses of rasG⁻ cells to cAMP were compared with the responses of rasC⁻ strain, these studies revealed that signal transduction through RasG is more important in chemotaxis and early gene expression, but that signal transduction through RasC is more important in ACA activation. Characterization of a rasC⁻/rasG⁻ mutant revealed that both cAMP chemotaxis and adenylyl cyclase (ACA) activation were negligible in this strain. The ectopic expression of carA from the actin 15 promoter restored early developmental gene expression to the rasC⁻/rasG⁻ strain, rendering it suitable for an analysis of cAMP signal transduction. Since there was negligible signaling through either the cAMP chemotactic pathway or the adenylyl cyclase activation pathway in this strain, it is clear that RasG and RasC are the only two Ras subfamily proteins that directly control these pathways. The mutational analysis of Switch I and Switch II regions also defined the key residues that generate functional differences between RasC and RasG. Rap1 is also activated in response to cAMP but its position in the signal transduction cascade was clarified by the finding that its activation was totally abolished in rasC⁻/rasG⁻/[act15]:carA and in rasG⁻ cells, but only slightly reduced in rasC⁻ cells. The finding that in vitro guanylyl cyclase activation is also abolished in the rasC/rasG⁻4act15]:carA strain identifies RasG⁻/RasC⁻ as the presumptive monomeric GTPases required for this activation. The phenotypes of the vegetative ras null mutants were also examined. The results indicate that RasG plays an important role in cytokinesis. The partial absence of chemotaxis to folate in rase cells compared to the total absence of chemotaxis to folate in rasC⁻/rasG⁻, and rasC⁻/rasG⁻/[act15]:carA cells suggests a compensatory role of RasC for RasG during this process, a similar phenomenon to that observed for cAMP chemotaxis by aggregating cells. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate