Open Access. Powered by Scholars. Published by Universities.®

Medicine and Health Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 9 of 9

Full-Text Articles in Medicine and Health Sciences

Signal Transduction Mechanisms For The Stimulation Of Lipolysis By Growth Hormone: A Dissertation, Rupert G. Yip Aug 1994

Signal Transduction Mechanisms For The Stimulation Of Lipolysis By Growth Hormone: A Dissertation, Rupert G. Yip

GSBS Dissertations and Theses

The purpose of this study was to investigate the mechanism of action of lipolysis by growth hormone in rat adipocytes. GH-induced lipolysis, in contrast to that of isoproterenol (ISO), is slow in onset (lag time >1h), small in magnitude (~2X basal). and requires corticosteroid. Evidence for direct coupling between GH receptors and adenylyl cyclase or G-proteins is lacking, and although we could detect no measurable change in cAMP content after treatment with GH + dexamethasone (Dex), it is likely that cAMP activation of protein kinase A is a central event in GH-induced lipolysis. Rp-cAMPS, a competitive antagonist of cAMP was equally ...


Transcriptional Regulation By The Saccharomyces Cerevisiae Centromere-Binding Protein Cp1: A Dissertation, Kevin F. O'Connell Jun 1994

Transcriptional Regulation By The Saccharomyces Cerevisiae Centromere-Binding Protein Cp1: A Dissertation, Kevin F. O'Connell

GSBS Dissertations and Theses

CP1 (encoded by the gene CEP1) is a sequence-specific DNA-binding protein of Saccharomyces cerevisiae that recognizes a sequence element (CDEI) found in both yeast centromeres and gene promoters. Strains lacking CP1 are viable but exhibit defects in growth, chromosome segregation, and methionine biosynthesis. To investigate the basis of the methionine requirement, a YEp24-based yeast genomic DNA library was screened for plasmids which suppressed the methionine auxotrophy of a cep1 null mutant. The suppressing plasmids contained either CEP1 or DNA derived from the PHO4 locus. PHO4 encodes a factor which positively regulates transcription of genes involved in phosphate metabolism via an ...


Studies On The Mechanism Of Deoxycytidylate Hydroxymethylase From Bacteriophage T4: A Dissertation, Karen Lorraine Graves Jun 1994

Studies On The Mechanism Of Deoxycytidylate Hydroxymethylase From Bacteriophage T4: A Dissertation, Karen Lorraine Graves

GSBS Dissertations and Theses

Deoxycytidylate (dCMP) hydroxymethylase (CH) catalyzes the formation of 5-hydroxymethyl-dCMP (Hm5CMP) from dCMP and methylene tetrahydrofolate (CH2THF), analogous to the reaction between dUMP and CH2THF catalyzed by thymidylate synthase (TS), an enzyme of known structure. The amino acid sequence identity between invariant TS residues and CH is at least 50%. Most of the residues which contact the dUMP and CH2THF in TS are conserved in CH. It is hypothesized that CH is homologous to TS in both structure and mechanism. The project described in this thesis tests this hypothesis.

In-vitro studies on catalysis ...


Human Immunodeficiency Virus Type-1 Infection Of Human Myeloid Cells, Cynthia Ann Pise-Masison Jun 1994

Human Immunodeficiency Virus Type-1 Infection Of Human Myeloid Cells, Cynthia Ann Pise-Masison

GSBS Dissertations and Theses

Infection with human immunodeficiency virus type 1 (HIV-1) results in a wide range of immunologic and hematopoietic abnormalities. The overall goal of this dissertation was directed toward obtaining a better understanding of the interactions of HIV-1 and myeloid cells in relation to the pathogenesis of AIDS. The human myelomonocytic cell line, HL-60, was used as a model system to determine if HIV-1 infects myeloid progenitor cells and subsequently, if infection affects their differentiation. HL-60 cells and the human prototypic T cell line, H9 were infected with three different HIV-l isolates (IIIB, PM213, and NL4-3) which are known to infect T ...


Molecular Determinants Of Glut1: Structure And Function: A Dissertation, Ralph J. Zottola Jun 1994

Molecular Determinants Of Glut1: Structure And Function: A Dissertation, Ralph J. Zottola

GSBS Dissertations and Theses

Hebert and Carruthers (1992) showed that the human erythrocyte glucose transporter is an allosteric complex of four GLUT1 proteins whose structure and substrate binding properties are stabilized by reductant-sensitive noncovalent subunit interactions. The GLUT1 tetramer dissociates into dimers upon exposure to reductant but subunits are not associated via disulfide bridges. Each subunit of SDS-denatured tetrameric GLUT1 exposes only two thiols while reduced denatured GLUT1 exposes all six sulfhydryl groups. They hypothesized that glucose transporter oligomeric structure and cooperative catalytic function resulted from noncovalent subunit interactions promoted or stabilized by intramolecular disulfide bridges. These interactions give rise to an antiparallel arrangement ...


A Mutational Analysis Of Structural Determinants Within The Newcastle Disease Virus Fusion Protein: A Dissertation, Julie N. Reitter Apr 1994

A Mutational Analysis Of Structural Determinants Within The Newcastle Disease Virus Fusion Protein: A Dissertation, Julie N. Reitter

GSBS Dissertations and Theses

The fusion protein of the Newcastle Disease Virus (NDV) contains three hydrophobic domains. To explore the topogenic signals of these domains, mutants were constructed in which each of the hydrophobic domains was deleted. The membrane insertion and topology of these proteins was characterized in a wheat germ cell-free translation system supplemented with canine microsomal membranes. The results indicated that the first 13 amino acids of the fusion protein are necessary to confer translation inhibition by SRP. Translocation of the nascent chains containing all or part of the first hydrophobic sequence resulted in the appearance of a species of higher molecular ...


Osteoclast Ontogeny-Experimental Studies In Two Osteopetrotic Mutations In The Rat: A Dissertation, Matthew Joseph Cielinski Apr 1994

Osteoclast Ontogeny-Experimental Studies In Two Osteopetrotic Mutations In The Rat: A Dissertation, Matthew Joseph Cielinski

GSBS Dissertations and Theses

Osteopetrosis is a metabolic bone disease in mammals characterized by a generalized skeletal sclerosis caused by reduced bone resorption. This reduced bone resorption is manifested in afflicted animals by abnormal bone shape, reduced or absent marrow cavities, extramedullary hemopoiesis, abnormal mineral homeostasis and absent or delayed tooth eruption. The available osteopetrotic animal mutations have been a constant source of fruitful investigations concerning the systemic regulation of osteoclastogenesis and bone metabolism. Tooth eruption, on the other hand, is a localized manifestation of the timely activation of bone resorption and bone formation on opposite sides of an erupting tooth. Its rate-limiting step ...


Cloning, Expression And Regulation Of Cyp3a10, A Hamster Liver Cytochrome P450 Involved In Lithocholic Acid And Steroid 6Β-Hydroxylation: A Dissertation, Jose Manuel Teixeira Jan 1994

Cloning, Expression And Regulation Of Cyp3a10, A Hamster Liver Cytochrome P450 Involved In Lithocholic Acid And Steroid 6Β-Hydroxylation: A Dissertation, Jose Manuel Teixeira

GSBS Dissertations and Theses

Bile acid metabolism is integrally involved in cholesterol homeostasis in mammals because it is the major means by which cholesterol is eliminated from the body. We have undertaken an effort to study the molecular mechanisms underlying the regulation of bile acid metabolism by isolating and characterizing the cDNA and gene for an enzyme that hydroxylates lithocholic acid (LCA) at position 6β, lithocholic acid 6β-hydroxylase; the first bile acid-induced gene reported. LCA is a very hydrophobic, toxic bile acid formed from chenodeoxycholic acid in the gut lumen upon reduction of the 7α-hydroxy group by microbial enzymes. The proper elimination of LCA ...


Analysis Of Temperature Sensing In Yersinia Pestis: A Dissertation, Nancy Palme Hoe Jan 1994

Analysis Of Temperature Sensing In Yersinia Pestis: A Dissertation, Nancy Palme Hoe

GSBS Dissertations and Theses

The lcrF gene of Yersinia pestis, the etiological agent of plague, encodes a transcription activator responsible for inducing expression of several virulence-related proteins (Yops) in response to temperature. The mechanism of this thermoregulation was investigated. Using a yopE::lacZ reporter fusion, lcrF-mediated thermal regulation was observed in Y. pestis and Escherichia coli. The lcrF gene was sequenced, the 30.8 kDa. LcrF protein identified and purified, and LcrF-dependent yopE-specific DNA binding activity was detected. A sequence similarity search revealed that LcrF exhibits 98% homology to VirF of Yersinia enterocolitica and significant homology to the carboxy termini of other ...