Thesis (Ph. D.)--Cornell University, August, 2006. / Vita. Includes bibliographical references (leaves 157-170.

Includes bibliographical references (p. 71-74).

Thesis (Ph. D.)--University of Chicago, Committee on Neurobiology, August 2002. / Includes bibliographical references. Also available on the Internet.

The Gilman's cyclic AMP binding assay was used to examine the possibility of adopting this method for adenylate cyclase determinations. Cyclic AMP determinations were not invalidated by the reagents used in the adenylate cyclase reaction. Cyclic AMP measured by the binding assay was directly proportional to adenylate cyclase activity. Although variability in recovery of cyclic AMP was obtained, it could be reduced by performing triplicate assays. Thus, the cyclic AMP binding assay, with some reservations, would appear applicable for measuring adenylate cyclase activity. Adenylate cyclase in rat brain was studied by using the cyclic AMP binding method for determination of product formed. Rat brain cortex was fractionated by the method of Whittaker. The highest adenylate cyclase activity was found in the fraction containing the highest acetylcholinesterase activity, and this fraction was shown by electronmicroscopic studies to be rich in synaptosomes. A modified sucrose gradient was used for isolating satisfactory synaptosomal fractions (the layer between 1.0 M and 1.1 M sucrose). Properties of synaptosomal adenylate cyclase were examined. The enzyme was dependent on the concentrations of ATP and Mg²⁺ or Mn²⁺ ion. The enzyme was stimulated by fluoride and inhibited by calcium ion. Synaptosomal adenylate cyclase was not sensitive to catecholamines or adenosine. No hormonal stimulation was obtained in the presence of GTP. In experiments where the effects of endogenous catecholamines were reduced by the addition of α and β adrenergic blocking agents or by prior treatment of the animals with reserpine, hormonal stimulation of adenylate cyclase in particulate preparations could not be demonstrated. / Medicine, Faculty of / Anesthesiology, Pharmacology and Therapeutics, Department of / Graduate

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / "May 2005" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Adenylate cyclase toxin (CyaA) is a key virulence factor of Bordetella pertussis, the causative agent of whooping cough. The toxin targets primarily myeloid phagocytes expressing CD11b/CD18 (αMβ2, CR3, Mac-1) and by elevation of cytosolic cAMP levels it paralyses their macropinocytic and opsono-phagocytic functions. Here, we dissected the cAMP-regulated pathway responsible for the block of macrophage macropinocytosis and characterized the capacity of CyaA-treated macrophages to shut- down Akt (protein kinase B, PKB) signaling; that controls nitric oxide (NO) production by macrophages. By using specific activators of protein kinase A (PKA) and for the exchange protein activated by cAMP (Epac), we show that activation of the cAMP effector Epac inhibits macropinocytosis in macrophages. Moreover, upon transfection of macrophages by the constitutively active and dominant negative variants of a downstream effector of Epac, the small GTPase Rap1, inhibition or upregulation of macrophage macropinocytosis was observed, respectively. It was reported previously that the Epac/Rap1 pathway regulates activity of tyrosin phosphatase SHP-1 as well as of protein phosphatase 2 A (PP2A). We show that inhibition of both tyrosin phosphatases and PP2A interferes with CyaA-mediated block of macropinocytosis. These...

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Thesis (Ph. D.)--University of Missouri--Columbia, 2001. / "May 2001." Typescript. Vita. Includes bibliographical references (leaves 66-80). Also available on the Internet.