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Full-Text Articles in Medicine and Health Sciences

An Examination Of The Hypothalamo-Neurohypophysial System Of The Rat: Restoration Of The Vasopressinergic System, Lynn M. Dibenedetto Dec 1997

An Examination Of The Hypothalamo-Neurohypophysial System Of The Rat: Restoration Of The Vasopressinergic System, Lynn M. Dibenedetto

GSBS Dissertations and Theses

The hypothalamo-neurohypophysial model has been studied for many years. Of note, when the axons of the magnocellular, peptidergic neurons of the supraoptic nucleus (SON) and paraventricular nucleus (PVN) are transected or crushed, varying degrees of polydipsia and polyuria ensue as the result of measurable losses of vasopressin (AVP) within the organism's circulation. Following insult, these hypothalamic cells show a remarkable capacity to reorganize themselves within the proximal areas of the infundibular stalk and median eminence and form what has come to be known as a new 'mini neural lobe' . While the surviving neurons sprout new projections toward the level ...


Studies Of Leishmania Major Pteridine Reductase 1, A Novel Short Chain Dehydrogenase, James Luba Sep 1997

Studies Of Leishmania Major Pteridine Reductase 1, A Novel Short Chain Dehydrogenase, James Luba

GSBS Dissertations and Theses

Pteridine reductase 1 (PTR1) is an NADPH dependent reductase that catalyzes the reduction of several pterins and folates. The gene encoding this enzyme was originally identified in Leishmania based on its ability to provide resistance to the drug methotrexate (MTX). The DNA and amino acid sequences are known, and overproducing strains of Escherichia coli are available. PTR1 has been previously shown to be required for the salvage of oxidized pteridines (folate, biopterin, and others). Since Leishmaniaare folate and pterin auxotrophes, PTR1 is a possible target for novel anti-folate drugs for the treatment of leishmaniasis.

PTR1 catalyzes the transfer of ...


In Vivo Functional Analysis Of The Saccharomyces Cerevisiae Swi/Snf Complex: A Dissertation, Loree Griffin Burns Jul 1997

In Vivo Functional Analysis Of The Saccharomyces Cerevisiae Swi/Snf Complex: A Dissertation, Loree Griffin Burns

GSBS Dissertations and Theses

Chromatin remodeling is crucial to transcriptional regulation in vivo and a number of protein complexes capable of altering genomic architecture in the budding yeast Saccaromyces cerevisiaehave been identified. Among these, the SWI/SNF complex, a 2 MDa, eleven subunit protein assembly, has been the most extensively characterized. The SWI/SNF complex is required for the proper expression of a number of genes in yeast, although it is completely dispensable for the expression of others. Likewise, some, but not all, transcriptional activator proteins require SWI/SNF activity in order to function in vivo. The goal of this thesis work was ...


In Vivo Regulation Of Murine Cytomegalovirus Infections: The Role Of Cell Surface Molecules And Mechanisms Of Control By Natural Killer Cells: A Dissertation, Chin Hun Tay Jul 1997

In Vivo Regulation Of Murine Cytomegalovirus Infections: The Role Of Cell Surface Molecules And Mechanisms Of Control By Natural Killer Cells: A Dissertation, Chin Hun Tay

GSBS Dissertations and Theses

The overall aim of this thesis was to determine how natural killer (NK) cells regulate virus infections in vivo. Anti-viral mechanisms by which NK cells control murine cytomegalovirus (MCMV) infection in the spleens and livers of adult C57BL/6 mice were first studied, revealing different mechanisms of control in different organs. Three days post-infection, MCMV titers in the spleens of perforin-deficient (perforin 0/0) mice were higher than in wild type controls, but no elevation of liver titers was found in perforin 0/0 mice. NK cell depletion in MCMV-infected perforin 0/0 mice resulted only in an increase in ...


Molecular Basis Of The Mechanism And Regulation Of Receptor-Gtp Binding Protein Interactions: A Thesis, Marianne Wessling-Resnick Jun 1997

Molecular Basis Of The Mechanism And Regulation Of Receptor-Gtp Binding Protein Interactions: A Thesis, Marianne Wessling-Resnick

GSBS Dissertations and Theses

The photon receptor, rhodopsin, and the GTP-binding regulatory protein, transducin, belong to a family of G protein-coupled receptors. The activation process through which guanine nucleotide exchange of the G protein is accomplished was investigated utilizing these components of the visual transduction system. Rhodopsin, modelled as an enzyme in its interaction with substrates, transducin and guanine nucleotides, was characterized to catalyze the G protein's activation by a double-displacement mechanism. Remarkable allosteric behavior was observed in these kinetic studies. Equilibrium binding studies were performed to investigate the molecular basis of the positive cooperative behavior between transducin and rhodopsin. These experiments show ...


Contribution Of Ordered Water Molecules And A Crucial Phenylalanine To Cooperative Pathway(S) In Scapharca Dimeric Hemoglobin: A Dissertation, Animesh Dev Pardanani Jun 1997

Contribution Of Ordered Water Molecules And A Crucial Phenylalanine To Cooperative Pathway(S) In Scapharca Dimeric Hemoglobin: A Dissertation, Animesh Dev Pardanani

GSBS Dissertations and Theses

The homodimeric hemoglobin (HbI) from the blood clam Scapharca inaequivalvis binds oxygen cooperatively and thus offers a simple model system for studying communication between two chemically identical sites. Although the individual subunits of HbI have the same myoglobin-fold as mammalian hemoglobins, the quaternary assemblage is radically different. Upon oxygen binding by HbI, only small tertiary changes are seen at the subunit interface in contrast to the relatively large quaternary changes observed with mammalian hemoglobins. Analysis of structures of this hemoglobin in the liganded (02or CO) and unliganded states has provided a framework for understanding the role of individual ...