Amino Acids, Peptides, and Proteins Commons^™

Radiation-Induced Glutamate Transport Alterations In Neuron-Astrocyte Coupling, Martha Celia Sanchez

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure of the central nervous system (CNS) to ionizing radiation is known to result in behavioral, cognitive, and motor deficits - effects similar to those seen in many neurodegenerative disorders. Neurons and astrocytes, two principal cell types in the brain, coexist as an interdependent metabolic unit via the neurotransmitter glutamate. Disruption of this metabolic coupling would have widespread effects within the CNS, therefore it is hypothesized that ionizing radiation impairs glutamate transport and metabolism, and increases oxidative stress, ultimately impairing neuron-astrocyte coupling. We propose to investigate the mechanism and determine the impetus for radiation-induced neurotoxicity by measuring the temporal sequence …

Right-Handed 14-Helix In Β3-Peptides From L-Aspartic Acid Monomers, Kamaljit Kaur, Tara Sprules, Wael Soliman, Reem Beleid, Sahar Ahmed

Pharmacy Faculty Articles and Research

β-Peptides made from L-aspartic acid monomers form a new class of β³-peptides. Here we report the first three-dimensional NMR solution structure of a β³-hexapeptide (1) from L-aspartic acid monomers in 2,2,2-trifluoroethanol (TFE). We show that 1 forms a right-handed 14-helical structure in TFE. α-peptides from naturally occurring L-amino acids adopt a right-handed α-helix whereas β³-peptides formed from β³-amino acids derived from naturally occurring L-amino acids form left-handed 14-helices. The right-handed 14-helical conformation of 1 is a better mimic of α-peptide conformations. Using the NMR structure of 1 in TFE, we …

A Novel And Generalizable Organotypic Slice Platform To Evaluate Stem Cell Potential For Targeting Pediatric Brain Tumors., Shengwen Calvin Li, William Gunter Loudon

Department of Cancer Biology Faculty Papers

Brain tumors are now the leading cause of cancer-related deaths in children under age 15. Malignant gliomas are, for all practical purposes, incurable and new therapeutic approaches are desperately needed. One emerging strategy is to use the tumor tracking capacity inherent in many stem cell populations to deliver therapeutic agents to the brain cancer cells. Current limitations of the stem cell therapy strategy include that stem cells are treated as a single entity and lack of uniform technology is adopted for selection of clinically relevant sub-populations of stem cells. Specifically, therapeutic success relies on the selection of a clinically competent …

Tyrosine Phosphorylation Of Villin: Effects On Actin Dynamics, Cell Morphology And Cell Migration, Alok Tomar

Theses and Dissertations (ETD)

Cell migration is a key aspect of many normal and abnormal biological processes, including embryonic development, defense against infections, wound healing, and tumor cell metastasis. In this study we demonstrate that an epithelial cell actin-binding protein, villin, plays a crucial role in the process of cell migration. Overexpression of villin in doxycyline-regulated HeLa Tet-off and MDCK Tet-off cells enhanced cell migration. We further demonstrate that tyrosine phosphorylation of villin by c-src is required for villin-induced cell migration. Previously, we identified four tyrosine phosphorylation sites in the amino-terminal domain of villin. I further identified six new sites in the carboxylterminal region …

Gene Expression In The Mouse Placenta: Developmental And Stress Responses, Ciprian P. Gheorghe

Loma Linda University Electronic Theses, Dissertations & Projects

Successful placental development is crucial for optimal growth, maturation, and survival of the embryo/fetus. Placental failure and placental pathology contributes to both morbidity and mortality of the fetus. We sought to understand normal placental development and also placental responses to stress using oligonucleotide microarray technology. To examine genetic aspects of normal placental development, we investigated gene expression patterns in the murine placenta at embryonic day 10.5 (E10.5), E12.5, E15.5, and E17.5. Hypoxia has been identified as a major stressor in placental and fetal development. In order to comprehend more completely hypoxic stress responses we sought to measure gene expression changes …

Linking Ligand-Induced Alterations In Androgen Receptor Structure To Differential Gene Expression: A First Step In The Rational Design Of Selective Androgen Receptor Modulators, Dmitri Kazmin, Tatiana Prytkova, C. Edgar Cook, Russell Wolfinger, Tzu-Ming Chu, David Beratan, J. D. Norris, Ching-Yi Chang, Donald P. Mcdonnell

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We have previously identified a family of novel androgen receptor (AR) ligands that, upon binding, enable AR to adopt structures distinct from that observed in the presence of canonical agonists. In this report, we describe the use of these compounds to establish a relationship between AR structure and biological activity with a view to defining a rational approach with which to identify useful selective AR modulators. To this end, we used combinatorial peptide phage display coupled with molecular dynamic structure analysis to identify the surfaces on AR that are exposed specifically in the presence of selected AR ligands. Subsequently, we …

Enterotoxin B Subunit Lectins As Adjuvants For Improvement Of Mucosal Vaccine, Nak-Won Choi

Loma Linda University Electronic Theses, Dissertations & Projects

In comparison with whole organism vaccines, subunit vaccines may be safer for immunization but may lack sufficient immunogenicity to provide complete immunity to the pathogen. To resolve this problem, bacterial and plant enterotoxin B subunit adjuvants containing a variety of receptor-binding properties were used to enhance the immunogenicity of rotavirus subunit vaccines. Enterotoxin B subunit adjuvants were employed to enhance protection against virus infection. Pentameric cholera toxin B subunit (CTB), shiga toxin-1 B subunit (STB) and monomeric ricin toxin B subunit (RTB) molecules were genetically linked to a 90 amino acid peptide from the simian rotavirus (SA11) nonstructural protein NSP4 …

Evaluation Of Cholera Vaccines Formulated With Toxin-Coregulated Pilin Peptide Plus Polymer Adjuvant In Mice, Jia-Yan Wu, William F. Wade, Ronald K. Taylor

Dartmouth Scholarship

Cholera is an acute diarrheal disease that is caused by the gram-negative bacterium Vibrio cholerae. The low efficacy of currently available killed-whole-cell vaccines and the reactinogenicity coupled with potential reversion of live vaccines have thus far precluded widespread vaccination for the control of cholera. Recent studies on the molecular nature of the virulence components that contribute to V. cholerae pathogenesis have provided insights into possible approaches for the development of a defined subunit cholera vaccine. Genetic analysis has demonstrated that the toxin-coregulated pilus (TCP) is the major factor that contributes to colonization of the human intestine by V. cholerae. In …

Effect Of Monounsaturated Fat Rich Almonds On Hemostatic And Inflammatory Factors In Healthy Adults, Kristianne M. Connell

Loma Linda University Electronic Theses, Dissertations & Projects

Background: The frequent consumption of nuts is inversely associated with the incidence of cardiovascular disease. Nuts are known to decrease the risk of cardiovascular disease by reducing serum total and low-density lipoprotein (LDL) cholesterol. Markers of inflammation including C-reactive protein, E-selectin and interleukin-6 have been proposed to be newer risk factors for cardiovascular disease. However, the influence of nuts such as almonds on markers of inflammation and hemostasis that influence cardiovascular disease risk is not currently known.

Objective: The objective of this study was to determine the effect of almond consumption on markers of inflammation and hemostatic factors in healthy …

Glucocorticoid Regulation Of Insulin Like Growth Factor Binding Protein-5 Gene Transcription In Human Osteoblasts, Xiaoying Wang

Loma Linda University Electronic Theses, Dissertations & Projects

Glucocorticoids (GCs) inhibit bone formation in vivo and inhibit osteoblast proliferation and collagen synthesis in vitro. These effects may be mediated by alterations in the insulin-like growth factor (IGF) system. In the present study of normal human osteoblast-like (HOB) cells, we tested the hypothesis that dexamethasone (Dex) inhibits the expression of IGF binding protein-5 (IGFBP-5). Dex decreased IGFBP-5 mRNA levels to 54% of control after 4 hr. Dex did not modify the decay of IGFBP-5 mRNA in transcriptionally arrested osteoblast cells. Dex decreased IGFBP-5 hnRNA levels to 67% of control after 2 hr, and the activity of the human IGFBP- …

Modulation Of The Pharmacokinetics And Pharmacodynamics Of Proteins By Polyethylene Glycol Conjugation, Reza Mehvar

Pharmacy Faculty Articles and Research

With the rapid advances in the field of biotechnology during the last decade, many peptides and proteins have been produced and evaluated for therapy of various diseases, including cancer. However, rapid clearance and the possibility of immunogenicity after the in vivo administration of these biotechnology-driven products have impeded their marketing. To circumvent these problems, synthetic and natural polymers such as polyethylene glycol (PEG) and dextrans, respectively, have been covalently attached to proteins, and some of these protein-polymer conjugates have shown promising therapeutic results. The conjugation of proteins with polymers usually causes a reduction in the recognition of the protein by …

Protein Adducts Of Iso[4]Levuglandin E2, A Product Of The Isoprostane Pathway, In Oxidized Low Density Lipoprotein, Robert G. Salomon, Wei Sha, Cynthia Brame, Kamaljit Kaur, Ganesamoorthy Subbanagounder, June O'Neil, Henry F. Hoff, L. Jackson Roberts Ii

Pharmacy Faculty Articles and Research

Levuglandin (LG) E₂, a cytotoxic seco prostanoic acid co-generated with prostaglandins by nonenzymatic rearrangements of the cyclooxygenase-derived endoperoxide, prostaglandin H₂, avidly binds to proteins. That LGE₂-protein adducts can also be generated nonenzymatically is demonstrated by their production during free radical-induced oxidation of low density lipoprotein (LDL). Like oxidized LDL, LGE₂-LDL, but not native LDL, undergoes receptor-mediated uptake and impaired processing by macrophage cells. Since radical-induced lipid oxidation produces isomers of prostaglandins, isoprostanes (isoPs), via endoperoxide intermediates, we postulated previously that a similar family of LG isomers, isoLGs, is cogenerated with isoPs. Now …

Nuclear Receptor Co-Repressor Gene Localizes To 17p11.2, A Frequently Deleted Band In Malignant Disorders, Michael W. Stacey, Jianxiang Wang, Rebecca L. Byrd, Johnson M. Liu, William G. Kearns

Bioelectrics Publications

The t(8;21) between the AML1 and ETO genes is a commonly seen genetic alteration in acute myeloid leukemia. Recently, we reported that the fusion partner ETO binds to the human nuclear receptor co-repressor (NCOR), a member of the NCOR/SIN3/histone deacetylase complex. This complex mediates transcriptional repression as a result of chromatin remodeling. Here, we used a combination of fluorescence in situ hybridization and hybrid panels to localize the human NCOR gene (NCOR) to chromosome band 17p11.2. The position of human NCOR on 17p11 raises the possibility of deranged transcriptional regulation in malignant disorders associated with deletions of 17p.

The Role Of Gap Junctions In Congenital Diseases Of The Heart, Scott Henry Britz-Cunningham

Loma Linda University Electronic Theses, Dissertations & Projects

Background. Gap junctions are thought to have a crucial role in the synchronized contraction of the heart and in embryonic development. Connexin43, the major protein of gap junctions in the heart, is targeted by several protein kinases that regulate myocardial cell-cell coupling. We hypothesized that mutations altering sites critical to this regulation would lead to functional or developmental abnormalities of the heart.

Methods. Connexin43 DNA from 25 normal subjects and 30 children with a variety of congenital heart diseases was amplified by the polymerase chain reaction and sequenced. Mutant DNA was expressed in cell culture and examined for its effect …

Developmental Expression Of Rat Target Of The Antiproliferative Antibody (Rtapa) Protein In The Brain, Clyde Dale Sullivan

Theses and Dissertations (ETD)

The present study defines the expression pattern of rTAPA (CD81) in the developing rat brain. rTAPA is a member of the tetramembrane spanning family of proteins, and like other members of this family, appears to be associated with the stabilization of cellular contacts. On immunoblots of the brain, rTAPA is present in higher levels than any other tissue examined: muscle, tendon, peripheral nerve, cartilage, liver, kidney, skin, and testicle. Immunohistochemical methods were used to define the distribution of rTAPA in the brain. This protein is expressed by ependyma, choroid plexus, astrocytes, and oligodendrocytes, and rTAPA is dramatically upregulated at the …

Cellular Responses In Escherichia Coli To Lethal And Sublethal Doses Of Ozone, Indira Ruth Komanapalli

Loma Linda University Electronic Theses, Dissertations & Projects

Ozone is a major component of photochemical smog. High levels of this pollutant, sufficient to affect human health are found in many urban areas worldwide. Though limited studies in humans are supported by extensive findings from animal experiments, a difficulty in interpreting the results of these experiments has lead to an ambiguity on the biochemical mechanism of ozone toxicity. To elucidate the mechanism by which ozone causes cell damage and eventual cell death we conducted a comprehensive study using Escherichia coli K-12 as a model.

Studies on the comparative inactivation of bacteriophage lambda (λ), Escherichia coli, and Candida albicans …

Signal Transduction In Bacterial Chemotaxis, Edward Heath Rowsell

Loma Linda University Electronic Theses, Dissertations & Projects

This study investigated the site of ATP utilization in the signal transduction pathway of bacterial chemotaxis and localized the point of convergence of a methylation-independent system of chemotaxis with the methylation-dependent system. The identity of the signal originating from the phosphotransferase system was investigated by substituting the fructose-inducible HPr-like protein FPr for HPr in transport and chemotaxis. In addition, a novel chemoattractant, glycerol, was identified for Salmonella typhimurium. Histidine-auxotrophic S. typhimurium strains ST23 (hisF) and ST171 (hisF cheB) were depleted for ATP. The times required for the bacteria to adapt to a step increase in serine, …

Phosphorylation Of The Rex Protein Of Human T-Cell Leukemia Virus Type 1, Yoshifumi Adachi, Terry D. Copeland, Chiaki Takahashi, Tetsuya Nosaka, Aftab Ahmed, Stephen Oroszlan, Masakazu Hatanaka

Pharmacy Faculty Articles and Research

Rex protein, the posttranscriptional regulator of human T-cell leukemia virus type I (HTLV-I), is required for the control of viral structural protein expression and virus replication. Rex is a phosphoprotein found predominantly in the cell nucleolus, whose function is thought to be regulated by its nucleolar localization and phosphorylation. Therefore, we investigated the in vivo phosphorylation of Rex protein in more detail. Phosphorylation of Rex occurred in all HTLV-I-infected cell lines examined in vivo, primarily at serine residues and to a very small extent at threonine residues. Treatment of cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) led to significant but transient enhancement of …

Effect Of Photoperiod On Developmental Morphology And Enolase Isoenzyme Immunohistochemistry In Rat And Djungarian Hamster Superficial Pineal Glands, Chalmer D. Mcclure

Loma Linda University Electronic Theses, Dissertations & Projects

The best understood functional activity of the pineal gland is its diurnal production of melatonin in response to environmental lighting cues. Several enzymes of the melatonin pathway respond to daily photoperiod changes, for example hydroxyindole-O-methyltransferase (HIOMT) and serotonin N-acetyltransferase (SNAT). Increased levels of the glycolytic enzyme neuron-specific enolase (NSE) are thought to reflect increased physiological demands placed on neurons and neuroendocrine tissues. Homodimer non-neuronal enolase isoenzyme (NNE) is immunolocalized to cells, and the hybrid enolase (consisting of subunits from NSE and NNE) has been seen in cerebellar stellate and basket cells. Although not rate limiting, concentrations of both NSE and …

Muscle Catabolism During A Protein Sparing Modified Fast As Measured By Urinary 3-Methylhistidine, Judith D. Nielsen

Loma Linda University Electronic Theses, Dissertations & Projects

The urinary excretion of 3-Methylhistidine was used as an index of muscle catabolism in four groups of obese persons receiving a Protein Sparing Modified Fast (PSMF). The composition of the supplements were as follows: Group I: 75 g protein, 25 g complex carbohydrate (starch) per day; Group II: 25 g protein, 75 g complex carbohydrate (starch) per day; Group III: 75 g protein, 25 g simple carbohydrate (glucose) per day; Group IV: 25 g protein, 75 g simple carbohydrate (glucose) per day. The PSMF lasted for seven days and a 24-hour urine sample was collected at the beginning of the …

The Synthesis Of Active Site Directed Inhibitors For The Lac Permease Of Escherichia Coli, Mahmoud Ahmed

Theses and Dissertations (ETD)

No abstract provided.

The Effect Of Varying Protein Intake On Trichinella Spiralis Infection In Mice, Clare K. Kwan

Loma Linda University Electronic Theses, Dissertations & Projects

Three hundred Swiss Webster albino mice three weeks of age were placed on low (8%), medium (24%), high (48%) protein levels and a commercial laboratory animal feed, Purina Chow for various lengths of time: (1) simultaneously with infection, and four weeks thereafter, (2) three weeks before infection and throughout the four-week infection period, and (3) six weeks prior to infection and during the infection period. The protein source was casein. Sixty of the 300 mice used served as noninfected controls, and the other 240 were each infected with 400 washed, suspended Trichinella spiralis larvae obtained from a rat by the …