Life Sciences Commons^™

Structural Studies Of Recombinant Human Β-Casein Proteins, Yilin Hu

Loma Linda University Electronic Theses, Dissertations & Projects

β-Casein is the major component (~80%) of the human casein system. Interacting with calcium and phosphates through its phosphorylated N-terminus, β-casein participates in the formation of micelles which carry these otherwise insoluble nutrients indispensable for the growth and development of newborns. Human β-casein, or fragments thereof, are also found to have biological effects such as enhancement of calcium absorption. So far, knowledge of micelle formation is limited and structural studies of β-casein, especially its N-terminal portion will provide a better understanding of the structure-function relationship of milk micelles.

To elucidate the role that the N-terminus of the protein plays in …

Phylogeography Of The Night Lizard, Xantusia Henshawi, From Southern California, Robert Edward Lovich

Loma Linda University Electronic Theses, Dissertations & Projects

The granite night lizard, Xantusia henshawi, is a highly specialized crevice dwelling lizard found in the Peninsular Ranges of southern California, United States and northern Baja California, Mexico. Generally, little morphological variation is seen in this species over a variety of habitats throughout its range, from elevations near sea level to approximately 2000 meters, and from Mediterranean habitats near the Pacific coast to arid desert habitat in the Colorado Desert of California. One exception is the variation seen in the subspecies X h. gracilis, which differs from X h. henshawi in morphology, allozymes, ecology, and natural history.

In …

The Role Of Brn-3.2 In Retinal Ganglion Cell Differentiation, Jerin Marie Wright

Loma Linda University Electronic Theses, Dissertations & Projects

Within the retina, the POU domain of transcription factors brn-3.0, brn-3.1, and brn-3.2 are present only in retinal ganglion cells. These genes are believed to be involved in establishing neural cell lineages in mammals. In this study brn-3.2 was examined by comparing the number of ganglion cells present during postnatal development in normal mice (+/+), in mice homozygous (-/-) for the brn-3.2 gene, and in adult mice with a heterozygous gene deletion (+/-) for brn-3.2. Optic nerve cross sections were imaged by electron microscopy, and axon profiles counted systematically by hand. These counts were then related to the nerve cross …

Effect Of Pollution On Genetic Diversity In The Southern California Bight, Xiao Li Ma

Loma Linda University Electronic Theses, Dissertations & Projects

Two intertidal invertebrate species, M galloprovincialis and Balanus glandula, were collected from seven different bay sites along the Southern California coast to test if environmental contamination is associated with the decrease of genetic diversity at the population level. Collections were made at three relatively pristine "clean" sites and four "impacted" sites which were exposed to heavy industrial or boating activity and which had previously, been identified as having measurable levels of pollution. The "Comet" assay (Single Cell Gel electrophoresis) was performed to measure single-strand DNA breaks in mussels at several of the sites in order to confirm differing impacts …

A Preclinical Model Of Ionizing Radiation And Tnf-Alpha Gene Therapy For Cancer, Jun Li

Loma Linda University Electronic Theses, Dissertations & Projects

Long term control of high-grade brain tumors is rarely achieved with current therapeutic regimens. This study sought to determine if pretreatment with plasmid DNA expressing Tumor Necrosis Factor-α (TNF-α) could enhance the effect of ionizing radiation in an aggressive, rapidly growing glioma tumor (C6) model. Plasmid DNA is an attractive vector system for delivery of foreign genes into eukaryotic cells due to its advantages including low immunogenicity in vivo, lesser toxicity and relatively low cost. We have constructed a plasmid-based mammalian expression vector (pGL1-TNF) to secrete human TNF-α from cancer cells. Plasmid DNA was successfully transfected into C6 cells …

Gender Variation In Croton Californicus (Euphorbiaceae), James Lynwood Smith Ii

Loma Linda University Electronic Theses, Dissertations & Projects

Croton californicus Muell. Arg. (Euphorbiaceae) is a subshrub suspected of being dimorphic with phase choices. Gender variation in C. californicus was studied in natural populations of southern California for three years (1994-96) to observe patterns of gender !ability. Some sites exhibited significantly male-biased sex ratios, and these sites often had the greatest number of monoecious morphs, cosexual plants with unisexual flowers. Gender variation was quantified for cosexual plants by calculating the Estimated Floral Gender (EFG) which varied from 1.00 (female) to 0.00 (male). The distribution of the EFG was highly skewed towards maleness. Monoecious individuals were then categorized by …

Molecular Systematics & Evolution Of The Ctenosaura Hemilopha Complex (Squamata: Iguanidae), Michael Ray Cryder

Loma Linda University Electronic Theses, Dissertations & Projects

Molecular variation within Ctenosaura hemilopha and among other Ctenosaura species are used to identify species boundaries, assess suitable systematic characters, identify evolutionary patterns within C. hemilopha mitochondrial DNA sequences and reconstruct species and area relationships among the various taxa. The molecular evolution of the C. hemilopha complex is analyzed using 1109 base pairs of mitochondrial DNA sequence from the cytochrome b and cytochrome oxidase III genes. Samples come from 22 individuals representing each of the five allopatric populations.

The results of a parsimony analysis showed a strongly supported, partially resolved set of relationships. The strict consenses tee formed in this …

Regulation Of Connexin43 By Phosphorylation, Maithili M. Shah

Loma Linda University Electronic Theses, Dissertations & Projects

Gap junctions play a crucial role in embryogenesis, especially of the heart where connexin43 is thought to be important for its formation as well as synchronized contraction. Several reports have shown that connexin43 protein is phosphorylated on serine residues in vitro and in vivo.

Studies performed in our laboratory have demonstrated that cell-to-cell communication in cells expressing connexin43 can be controlled rapidly and reversibly by microinjection of active protein kinases or phosphatases that target serine or threonine residues. Phosphorylation by cAMP-dependent protein kinase (PKA) seems to favor channel opening, whereas the effect of protein kinase C (PKC) on channel gating …

Neuronal And Metabolic Increases In Pedunculopontine Nucleus Of Parkinson's Rats, Jonathan Dennis Carlson

Loma Linda University Electronic Theses, Dissertations & Projects

The theoretical mechanisms underlying the symptoms of Parkinson’s disease are based on dysfunctional output from the basal ganglia projected to the cortex via the thalamus. However, the subthalamic nucleus (STN) and substantia nigra pars reticularis (SNr) as part of the basal ganglia, also project to the brainstem, in particular to the pedunculopontine nucleus (PPN). Both the STN and SNr have altered neuronal activity in the 6-hydroxydopamine (6-OHDA) Parkinson’s model rat. Thus, it is hypothesized that the PPN is altered in this model of Parkinson’s disease.

This hypothesis was examined by comparing the rates of glucose metabolism and spontaneous neuronal activity …

Maternal Modulation Of Neonatal Immunity, Omar R. Fagoaga

Loma Linda University Electronic Theses, Dissertations & Projects

Although the neonatal immune system is functionally immature, immune response capabilities are not the same in all newborns. The objective of this thesis was to determine development of immunocompetence and test the hypothesis that activation of maternal inflammatory immunity during pregnancy influences maturation of the neonatal immune system.

Lymphocytes in blood and spleen were immunophenotyped by flow cytometric analysis to determine differentiation characteristics, and splenocytes were assessed for cytokine production capabilities. In normal Th2-prone outbred (CD-1) mice, an adult repertoire of naïve lymphocytes has developed by day 10 and memory cells by day 20, in blood and spleen. However, in …

Dna-Dna Checkerboard Hybridization To Identify Bacteria In Human Plaque Samples, Jasan Lee Zimmerman

Loma Linda University Electronic Theses, Dissertations & Projects

Previous research has shown that using DNA probes to identify the presence of specific bacteria in human plaque samples is superior to the commonly used anaerobic cultural procedures. Some periodontal pathogens are either uncultivable or very difficult to grow, such as Prevotella intermedia, P. nigrescens, and Eubacterium brachy. Digoxygenin probes were prepared for 15 oral bacteria. These probes were used with a checkerboard DNA-DNA hybridization scheme to analyze whether human plaque samples contained any of the 15 bacterial species. Our results have shown that this method is successful in identifying bacterial DNA present in the subgingival patient plaque …

Effect Of Obturation And / Or Coronal Seal On The Success Of Root Canal Therapy : An In Vivo Histologic Investigation, Douglas Snider

Loma Linda University Electronic Theses, Dissertations & Projects

Numerous studies have examined coronal leakage with in vitro protocols. A search of the literature showed the absence of a long term in vivo, histologic study, examining the effect of coronal and/or radicular leakage on periradicular health.

The purpose of this study was to evaluate the effect of obturation and / or coronal seal in preventing the formation of periradicular lesions in dogs over time. The study was conducted on six beagle dogs. Premolars were cleaned and shaped. Sixteen roots in each dog were randomly assigned to one of four treatment groups of equal size. Group one was obturated using …

The Molecular Systematics Of The Side-Blotched Lizards (Iguania: Phrynosomatidae: Uta), Bradford Damion Hollingsworth

Loma Linda University Electronic Theses, Dissertations & Projects

The lizard genus Uta comprises nine currently recognized species with the center of diversity occurring on islands in the Gulf of California and Pacific Ocean. The molecular evolution of the side-blotched lizards is analyzed using 1132 base pairs of mitochondrial DNA sequence from the cytochrome b and cytochrome oxidase III genes. Samples come from 98 'individuals from 50 islands in the Gulf of California and Pacific Ocean and 48 adjacent populations from Baja California Sur, Baja California, California, New Mexico, and Sonora. All currently recognized species are represented. Both maximum parsimony and maximum likelihood were used to reconstruct phylogenetic relationships. …

The Immunology Of Parturition, Ari Mayer Mackler

Loma Linda University Electronic Theses, Dissertations & Projects

Macrophage-derived factors have been implicated in the etiology of preterm labor but little is known about trafficking of this immune cell into the uterus or its regulation of uterine contractility in mice. Enhanced number and activation of macrophages was hypothesized to precede parturition. Studies characterized contractile activity and the distribution of macrophages in the uterus of C3/HeN mice before and after term (=day 19). Contractile activity by uterine strips on days 15 and 18 of pregnancy, the day of delivery, and 1 day postpartum indicate that an endogenous oscillator sustains high frequency contractions. Modest acceleration of the pacemaker occurred before …

Regulation Of Synthesis And Actions Of Bone Growth Factors, Rashmi Malpe

Loma Linda University Electronic Theses, Dissertations & Projects

Among the many bone growth factors, this study focused on the IGF and BMP systems because of some of their unique functions, namely, IGFs function both as local and systemic agents and BMPs are capable of inducing de novo bone formation at non-skeletal sites. There is varied osteoblast differentiation in and load bearing on the skeletal system which led to the first study whose hypothesis was that these skeletal site dependent differences are associated with site-specific differences in IGF system components' production. Results from their quantitation in the CM of normal HBC derived from calvaria, mandibles, ribs, vertebrae, and marrow …

Functional Analysis Of Human Igfbp-6 In Human Osteoblasts, Tao Yan

Loma Linda University Electronic Theses, Dissertations & Projects

Insulin-like growth factor binding proteins (IGFBPs) are a family of six secreted proteins that bind to and modulate the functions of insulin-like growth factors (IGF-I and IGF-II). As a relatively new member of the IGF system, IGFBP-6 was found to be produced by human osteoblasts and exert significant biological effects on human osteoblasts.

Our previous studies indicated that all-trans retinoic acid (ATRA) caused more than a10 fold increase in IGFBP-6 production and a50-60% reduction of ALP activity in human osteoblasts. Based on these findings, we proposed the hypothesis that ATRA induced human osteoblast differentiation was mediated at least in part …

Acute Effects Of Whole-Body Proton Irradiation On The Immune System Of The C57bl/6 Mouse, Eric H. Kajioka

Loma Linda University Electronic Theses, Dissertations & Projects

The acute effects of proton whole-body irradiation (WBI) on leukocytes, lymphocytes, and hematological parameters in the spleen and blood of C57BI/6 mice were examined and compared to the effects of photon (gamma) WBI derived from a 60cobalt (60Co) source. Adult, female C57BL/6 mice were exposed to a single dose (3 Gy, 0.4 Gy/min dose rate) of either proton WBI at the Bragg peak, proton WBI at the entry plateau, or Co WBI, and sacrifice intervals were at 1,4, 7, and 10 days post- WBI. Flow cytometry analysis of the spleen and peripheral blood showed depression in cell counts for all …

Antitumor Effect Of Il-2, P53, And Bax Naked Gene Transfer In C6 Glioma Cells, Peyman Haghighat

Loma Linda University Electronic Theses, Dissertations & Projects

[Abstract not included]

Use Of Bioinformatics In The Analysis Of Chemotaxis Proteins, Sean Andrew Bulloch

Loma Linda University Electronic Theses, Dissertations & Projects

Bacterial chemotaxis is one of the best-known signal transduction systems. Levels of attractants and repellents are sensed in the surrounding environment by various chemoreceptors. The signal is passed to the excitation pathway via the transfer of a phosphoryl group from the receptor-associated histidine kinase CheA to the response regulator CheY. Phospho-CheY binds to the flagellar motor switching the direction of rotation of the flagella and thus allowing the cell to move towards or away from the attractant or repellent. The phosphatase CheZ removes the phosphoryl group from phospho-CheY restoring default flagellar rotation. Adaptation to stimuli occurs via addition of methyl …

Engineering Secreted Proteins For Gene Transfer And Dna Vaccination, Jingxue Liu

Loma Linda University Electronic Theses, Dissertations & Projects

In recent years gene therapy has become a promising way of alleviating incurable human ailments, its concept emerging as the ultimate therapy for many infectious and genetic diseases. Two important aspects of the development of successful gene therapy protocols are the ability to monitor gene transfer readily, and the establishment of new protocols for treating specific diseases. In this work, Renilla luciferase and human glutamic acid decarboxylase (GAD) 65 were engineered for secretion to address some aspects of these issues.

Secreted reporter proteins are promising tools to study gene transfer and expression in a non-destructive manner, and bioluminescent proteins are …

Effects Of Long-Term, High-Altitude Hypoxemia On Fetal Ovine Coronary Arteries, Felizabel C. Garcia

Loma Linda University Electronic Theses, Dissertations & Projects

To our knowledge, this is the first series of in vitro studies to investigate the effects of long-term, high-altitude hypoxemia on the contractility of fetal coronary vessels, namely the left circumflex, left anterior descending, and right coronary arteries. We have found that in response to chronic hypoxia, isolated fetal ovine coronary arteries exhibit attenuated contractile responsiveness to potassium and the thromboxane A2 mimetic. U46619. Furthermore, long-term, high-altitude hypoxia produced no significant alteration in the maximum relaxation response and sensitivity to adenosine in all vessel groups examined. We also addressed the possible role of nitric oxide (NO) in the pharmacological responsiveness …