Molecular Genetics Commons^™

Diseased Thyrocytes Have Aberrant Communication And Tnf Receptor Secretion, Mary Labue

Loma Linda University Electronic Theses, Dissertations & Projects

Autoimmune diseases are a world-wide health concern and are an intense area of investigation. However, one area of research has been largely ignored. This involves the contribution of the target tissue to the disease process. We hypothesized that cell-cell communication is disrupted by lymphocytic infiltration and advancing fibrosis and this disruption results in altered target cell responses to immune components produced at the site of inflammation, including Tumor Necrosis Factor-alpha (TNF- α).

We have used thyroiditis as our model of autoimmunity and have documented the development of spontaneous thyroiditis in MRL-lpr/lpr mice. We have found aberrant connexin expression in …

Expression Of The Human Milk Protein, Beta-Casein : In Transgenic Potato Plants, Wendy Roberts

Loma Linda University Electronic Theses, Dissertations & Projects

Mother’s milk is recommended by the nutritional and pediatric communities as the best food for suckling infants. For non breast-fed infants, bovine milk-based formulas have been regarded as a suitable substitute. In the early 1900's, physicians found that foreign proteins in cow milk were responsible for gastrointestinal disease and even digestive collapse of the newborn fed a cow milk-based diet¹⁶. The allergenicity of cow milk for the human infant appears to be caused predominantly by p-casein¹⁷. In this research, the cDNA encoding human p-casein was introduced into potato cells under the control of the bidirectional, auxin-inducible …

Active Inhibition Of T Cell Proliferation By Monocytes, Dean Anthony Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Monoclonal antibodies (mAb) to MHC class II molecules (anti-class II mAb) have been well described in their ability to inhibit T cell activation. The most current model is that anti-class II mAb interfere directly with the T cell receptor-major histocompatibility complex crosslinking which is necessary for T cell activation. The anti-CD3 mAb, OKT3, is an MHC class II molecule-independent mitogen which causes T cell activation by direct ligation of the TCR-CD3 complex. OKT3 and a panel of anti-class II mAb were used to dissect the individual roles played by these two receptors in activation and inhibition of peripheral blood mononuclear …

Developmental Regulation Of The Murine Cd4 Gene, Rhonda Kay Hansen

Loma Linda University Electronic Theses, Dissertations & Projects

CD4 is a membrane bound glycoprotein that plays an important role in T cell development and activation. An extensive analysis of the CD4 locus identified potential transcriptional control elements located 5' of the promoter and within the first intron. Since the molecular mechanism for the control of CD4 expression during T cell development had not been determined, it is the focus of this dissertation. A series of recombinant DNA constructs were made to determine the contribution of putative transcriptional control elements in regard to CD4 expression, and to identify elements being used to control CD4 expression during T cell development. …

Regulation Of The Insulin-Like Growth Factor System By Retinoic Acid In Human Osteoblast Cells, Yuehua Zhou

Loma Linda University Electronic Theses, Dissertations & Projects

Retinoic acid (RA) is an important regulator of growth and differentiation in many cell types, including bone. However, its effects on human osteoblast cell growth and differentiation have not been well studied. Therefore, I investigated the effect of RA on proliferation and differentiation of normal human bone cells (HBCs) and human osteosarcoma, SaOS-2 cells. RA decreased baseline as well as serum-stimulated proliferation in normal HBCs. To determine the effect of RA on differentiation, expression of several osteoblastic differentiation markers were studied. RA decreased type I procollagen mRNA levels and l,25(OH)₂D₃-stimulated osteocalcin and alkaline phosphatase (ALP) mRNA …

A Model Of Cytomegalovirus Association With The Development Of Heart Graft Atherosclerosis, Evan Skowronski

Loma Linda University Electronic Theses, Dissertations & Projects

The development of graft atherosclerosis in heart transplant recipients has been associated with the development of post-transplant cytomegalovirus infection. The mechanism of this involvement, however, remains unclear. I undertook a study to determine the role of cytomegalovirus in the development of graft atherosclerosis. First, a rapid method of detecting cytomegalovirus based on capillary polymerase chain reaction and gel electrophoresis was employed to determine the presence of cytomegalovirus in a wide variety of clinical samples. Detection of cytomegalovirus is a lengthy procedure under normal conditions, and timely detection of cytomegalovirus in transplant recipients may allow intervention early enough to block the …

Transcriptional Regulation Of Insulin-Like Growth Factor : Binding Protein-4 By Protein Kinase A And Protein Kinase C Signal Transduction Pathways In Human Bone Cells, Kuk-Wha Lee

Loma Linda University Electronic Theses, Dissertations & Projects

The Insulin-like Growth Factor (IGF) system is an important local regulator of osteoblast proliferation, the primary determinant of bone formation. Six IGF Binding Proteins (IGFBPs) either inhibit or enhance IGF actions. Previous studies have shown that IGFBP-4 is an important negative regulator of osteoblast cell proliferation and that agents such as PTH which increase intracellular cAMP significantly increase expression of IGFBP-4 at the protein and mRNA levels. The underlying molecular mechanism which accounted for IGFBP-4 expression had not been determined and was the focus of my dissertation. Agents which increase intracellular cAMP rapidly increased IGFBP-4 mRNA levels. Nuclear run-off experiments …

The Expression And Regulation Of The Hsdk Genes Of Escherichia Coli K-12, Ainu Parkash

Loma Linda University Electronic Theses, Dissertations & Projects

The DNA restriction and modification (R-M) genes in bacteria play a defensive role in the organism, offering protection to the host from invaders such as bacteriophages. The expression of these genes in E. coli K-12 had not previously been studied due to the complexity of the EcoK R-M enzymes. The use of lacZ gene fusion techniques allowed studies of the expression of the hsdK genes for the first time. Operon fusions of Mu(/ac) to the hsdK genes show that the two hsdK promoters, p _res and p _mod, are weak (50 Miller units) and that …

Characterization Of Hsd::Mudx128 Operon Fusion Mutant Of Escherichia Coli K-12, Marjorie Ann T. Reyno

Loma Linda University Electronic Theses, Dissertations & Projects

The study of the regulation of gene expression in complex genes can be facilitated by the use of operon fusions which place a well characterized lacZ gene under the control of a promoter of interest. An hsd::MudX128 operon fusion mutant of E. coli K-12 isolated by Prakash (1986) was observed to have a high β-galactosidase activity (1000 units), ten to twenty times higher than other hsd::MudX mutants. This β-galactosidase activity was suppressed to a very low level (25 units) by the introduction of an F’ plasmid, F'101, which carries the 98 min to 2 min region of the …

Genetic Transformation In Salmonella Typhimurium, Siao Ping Tasi

Loma Linda University Electronic Theses, Dissertations & Projects

Plasmid transformation is an essential step in many gene cloning experiments. In Salmonella tynhimurium, mutants of rough strain have shown improved transformation frequency previously. In this work a stable restriction-minus (r^-) and modification-plus (m⁺) strain and its derivatives were constructed. Effect of restriction barrier on transformation of plasmid pBR322 was tested. Several factors which may affect transformation frequency have been systematically examined to determine the optimum conditions for transformation in S. tvphimurium. Efforts were made to simplify the procedure.

Using pBR322 plasmid as an experimental model, the r^- strain demonstrated 10⁵ to …

Molecular Weight Determinations Of Some Salmonella Potsdam Bacteriophage Dna's, Winston H. Richards

Loma Linda University Electronic Theses, Dissertations & Projects

Two group A phages, P9c/2 and P4/2, were studied. Their density, sedimentation velocity, and biochemical properties were compared. Their densities were determined by density gradient centrifugation in 38.3% cesium chloride. Sedimentation velocity was used to determine their molecular weights. To accomplish this, the DNA of P9c/2 and P4/2 was labeled with tritium and T₂ DNA, labeled with ³²P, was used as a standard. The DNA of P9c/2 and P4/2 was separately mixed with T₂ DNA and centrifuged in a 0-15% sucrose gradient. The molecular weights were calculated using the formula D₂/D₁= (M_{2 …}

Biochemical Properties Of Salmonella Potsdam Bacteriophage P4/2, Clyde L. Roggenkamp

Loma Linda University Electronic Theses, Dissertations & Projects

Over 90% recovery of phage P4/2 was realized with differential centrifugation concentration and purification, whereas only about 16% was recovered from the aqueous two-phase polymer - Genetron - ECTEOLA-cellulose column system. Purity of preparations was greatest with the density gradient centrifugation (A₂₆₀ = 2.66 and A₂₈₀ = 1.80 per 10¹² plaque-forming units). With the chemical system of concentration and purification followed by an ECTEOLA anion exchange run, the A₂₆₀ was 6.6 and the A₂₈₀ was 4.3.

Three tests were employed to determine the configuration of P4/2 DNA: (1) a formalin denaturation test, (2) a thermal …