Laboratory and Basic Science Research Commons^™

Development Of Chimeric Type Iv Secretion Systems For Transfer Of Heterologous Substrates Across The Gram-Negative Cell Envelope, Trista M. Berry

Dissertations and Theses (Open Access)

Many bacteria use Type IV Secretion Systems (T4SSs) to aid in pathogenesis by translocating virulence factors across the cell envelope and into eukaryotic cells. These systems are structurally and functionally diverse, but are often compared to the archetypal VirB/VirD4 T4SS of Agrobacterium tumefaciens. This system is composed of the VirD4 type IV coupling protein (T4CP) and 11 VirB subunits (VirB1-11) that assemble as the secretion channel and an extracellular pilus. The T4CP is an inner membrane ATPase that interacts with T4SS substrates and the secretion channel, and is thought to link substrates with the secretion channel and possibly energize …

Energy Stress Causes Chaperones To Assemble Into Cytoplasmic Complexes, Kimberly J. Cope

Dissertations and Theses (Open Access)

The majority of proteins require molecular chaperones to assist their folding into tertiary and quaternary structures. Certain stresses can compromise the weak hydrophobic forces responsible for these structures and lead to protein unfolding, misfolding, and aggregation. Aggregates of proteins are hallmarks of devastating diseases such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. Fortunately, bacteria, plants, and fungi have a potent disaggregase, named Hsp104 in Saccharomyces cerevisiae. Recently, heat-induced aggregates, termed Q-bodies, were found to contain three molecular chaperones: Hsp70, Hsp104, and Hsp42. Their coalescence from small puncta into larger inclusions required Hsp104. During glucose deprivation, a stress that isn’t known to …

The Effects Of Lipoxin A4 (Lxa4) On Neutrophil Biology In Sepsis, Benedict Wu

Graduate School of Biomedical Sciences Theses and Dissertations

During sepsis, neutrophils are inappropriately activated and have prolonged lifespans, thus becoming dysfunctional. Excessive neutrophil activation can lead to tissue injury while neutrophil dysfunction can lead to decreased free radical production and reduced phagocytosis, preventing the host from clearing preexisting infections. Lipoxin A4 (LXA4) is a specialized pro-resolution mediator which reduces neutrophil migration and expression of proinflammatory mediators. Intact neutrophil functions are critical for the host to efficiently clear invading pathogens. The effects of LXA4 on neutrophil function in sepsis have not been established. Using the cecal ligation and puncture (CLP) model of sepsis, LXA4 administered 1 h after sepsis …

The Prevalence And Effect Of Wolbachia Infection On The Brown Widow Spider (Latrodectus Geometricus), Brittany Dane' Arrington

College of Graduate Studies: Theses & Dissertations

Wolbachia was recently identified in the Brown Widow Spider (Latrodectus geometricus). This symbiont has not previously been found in this genus, therefore the consequences on the host’s population dynamics are unknown. The frequency of endosymbiont infection can provide insight into the population dynamics of the host as this bacteria is known to alter host life history. In my 1^st chapter I determine the prevalence of Wolbachia pipentis infection in in the Brown Widow Spider (Latrodectus geometricus) from five locations in the Southeastern United States. Infection frequency differed significantly among sampling locations, ranging from 20% to …

Bacterial Transcription Factors Grea, Greb And Dksa: Characterization Of Their Interaction With Rna Polymerase And Molecular Mechanism Of Action, Andrey Parshin

Graduate School of Biomedical Sciences Theses and Dissertations

The activity of RNA polymerase (RNAP), the key enzyme of transcription process, is regulated by a large number of transcription factors acting at each step of the transcription cycle. Our research project is focused on studying the structure and function of bacterial transcript cleavage factors GreA, GreB and the stringent response regulator DksA. Gre factors bind in the secondary channel of RNAP in backtracked (inactive) ternary elongation complexes and stimulate the enzyme's intrinsic RNase activity, which is required for suppression of transcription pause and arrest, enhancement of transcription fidelity, and efficient promoter escape. DksA also acts through the RNAP secondary …

Life Support: Long Term Storage Of Solid Waste In An Enclosed Membrane System, Emmy O. Trieu, Michael Flynn, Rocco Mancinelli

STAR Program Research Presentations

In deep space missions, maintaining life support is of the utmost priority. In such a closed system, human waste must be stored and treated. Simulated feces (ersatz) will be inoculated with microbes representing normal fecal flora, mixed with urine brine and shredded refuse of products typically used in space missions. Composting methods often use alternating layers of waste with scraps of carboniferous materials (finely shredded refuse). By preparing membrane bags with a homogenized ersatz and carboniferous refuse mixture and membrane bags with alternating layers of ersatz and carboniferous refuse, it may be possible to monitor anaerobic thermophillic digestion of the …

Coccidia Of Gerbils From Mongolia, Ethan Thomas Jensen

School of Biological Sciences: Dissertations, Theses, and Student Research

In this study, gerbils collected in the Mongolia over the summers of 2009-2012 were examined for coccidia. In total, 171 gerbils of three species from 22 localities were examined for coccidia. Coccidian oocysts were identified from 21 gerbils, but those found in 1 of those gerbils were probably pseudoparasites of the host from which they were recovered. From the remaining 20 gerbils, 7 morphotypes of Eimeria and 1 morphotype of Isospora were identified. Four of the 7 morphotypes of Eimeria were attributed to new species which were described in this study. In addition, 10 previously described species of Eimeria were …

Analyzing Environmental Microbes For Genomic Regions Promoting Ionic Liquid Tolerance In E. Coli, Ann Nguyen, Alison Richins, Thomas Rüegg, Steven Singer, Michael Thelen

STAR Program Research Presentations

Ionic liquids (ILs) are promising as solvents to increase the efficiency of biofuel production; however, ILs are toxic to microbes used in the fermentation of liquid fuels. To engineer IL resistant biofuel hosts, environmental bacteria were screened for tolerance, and these were used to create gene libraries to test in E. coli. Future characterization of these libraries using molecular techniques will be used to identify genes that contribute IL-tolerance to transformed microbes.

Why Do We Collect?, Allison Marsh

Section 2: Imaging the Microscopic

No abstract provided.

Spotlight On Usc: A.C. Moore Herbarium, Allison Marsh

Section 2: Imaging the Microscopic

No abstract provided.

Imaging And Aesthetics, Allison Marsh

Section 2: Imaging the Microscopic

No abstract provided.

Novel Mechanisms Of Antigen Processing That Enhance Bcg Vaccine Efficacy, Christopher R. Singh

Dissertations and Theses (Open Access)

Mycobacterium tuberculosis, the causative agent of tuberculosis, is the most lethal single infectious agent afflicting man today causing 2 million deaths per year. The World Health Organization recommends a vaccine as the best option to prevent this disease. The current vaccine, BCG, has a variable efficacy and does not protect adults. It is known that BCG vaccine becomes sequestered in special phagosome compartments of macrophages that do not fuse with lysosomes. Since lysosome fusion is necessary for peptide production and T cell priming leading to protective T_H1 immunity, we hypothesized that vaccine efficacy is reduced and occurs perhaps …

Investigation Of Bovine Herpesvirus 1 (Bhv-1) Encoded Infected Cell Protein 0 (Bicp0), Natasha N. Gaudreault

School of Biological Sciences: Dissertations, Theses, and Student Research

Bovine herpesvirus 1 (BHV-1) is a significant pathogen of cattle.  Following acute infection, BHV-1 establishes a latent infection that persists for the life of the infected host.  Stress induced factors cause the virus to reactivate from latency, resulting in virus transmission and transient immune suppression.  BHV-1 encoded bICP0 is expressed early and constitutively throughout productive infection.  bICP0 is critical for efficient viral replication, virulence, and reactivation in cattle because it stimulates viral transcription and interferes with innate immune responses.  bICP0 potentially interacts with a variety of proteins to activate viral gene expression and inhibit innate antiviral defenses.  bICP0 localizes to …

The Importance Of The Set2 Gene In The Virulence Of Candida Albicans, Molly Marchel

Honors Capstones

Capstone submitted as a graduation requirement for BSU Honors Program.

A Metagenomic Study Of The Tick Midgut, Daniel T. Yuan

Dissertations and Theses (Open Access)

A Metagenomic Study of the Tick Midgut
Daniel Yuan, B.S.
Supervisory Professor : Steven J. Norris, Ph.D.
Southern tick–associated rash illness (STARI) or Master’s disease is a Lyme-like illness that occurs following bites by Amblyomma americanum, the lone-star tick. Clinical symptoms include a bull’s eye rash similar to the erythema migrans lesions of Lyme disease, as well as fever and joint pains. Lyme disease is caused by Borrelia burgdorferi and related spirochetes. However, B. burgdorferi has not been detected in STARI patients, or in ticks in the South Central U.S. The causative agent of STARI has not been identified, …

Methods Used By Dr. R. K. Benjamin, And Other Mycologists, To Isolate Zygomycetes, Gerald L. Benny

Aliso: A Journal of Systematic and Floristic Botany

The methods that Dr. Richard K. Benjamin used to isolate Zygomycetes are discussed. These processes involved the following five steps: (1) collection, (2) plating, (3) isolation, (4) culture, and (5) maintenance. Additional methods, materials, and modifications used to isolate Zygomycetes are summarized. The author considers the flattening of the aerial hyphae onto the substrate of the faster- and higher-growing Mucorales for several consecutive days to be the critical step in isolating species of Coemansia, Piptocephalis, Syncephalis, and Dimargaritales. The methods used by other scholars to isolate, culture, and study many taxa in Zygomycetes also are discussed.

The Effect Of Radiation And Repeated Sub-Culturing On Tgf-Β1 Signaling In Frtl-5 Cells, Cheryl G. Burrell

Loma Linda University Electronic Theses, Dissertations & Projects

From our ongoing in vitro studies using the Fisher Rat Thyroid cell line-5 (FRTL-5) we recorded accelerated growth, reduced follicularization and reduction in thyroxin release that occurred as the cells were repeatedly sub-cultured. We also recorded that these changes occurred earlier and more rapidly following radiation exposure. We determined that TGF-β1 production increased under both conditions. We hypothesized that alteration in the TGF-β1 signaling pathway contributed to the changes observed in the cellular properties of FRTL-5 cells. Our objective was to examine some of the players in the TGF-β1 signaling pathway to determine whether radiation and/or repeated subculturing promoted changes …

Radiation-Induced Increases In Pkc Modulate Integrin Expression And Contribute To Fibrotic Changes, Pinal Rushikesh Pandya

Loma Linda University Electronic Theses, Dissertations & Projects

The sequences of events in fibrosis are similar to those in wound healing; however, the normal termination and resolution stages do not take place. The initial cellular response following ionizing radiation involves accumulation of the ECM (extracellular matrix) including collagen, fibronectin and the interaction of many growth factors (cytokines) with their receptors. There are a number of unanswered questions regarding many aspects of radiation-induced fibrosis, including the initial triggers and physical changes that initiate the process. We have confirmed that elevated pKC and other cellular changes following radiation are similar to those found at sites of inflammation. This information leads …

An In Vitro Model Of Ovarian Cancer: Studying The Effects Of Talc And Pycnogenol®, Amber Renée Buz'zard

Loma Linda University Electronic Theses, Dissertations & Projects

Ovarian cancer is the sixth most common cancer and accounts for more deaths than any other cancer of the female reproductive system. The American Cancer Society has suggested that poor diet, talc and industrial pollutants may increase the risk of developing ovarian cancer. Talc is ubiquitous and concern is raised about its safety, role as a possible carcinogen and known ability to cause irritation and inflammation. Due to the silent nature of ovarian cancer, chemoprevention is a high priority. The most useful chemopreventive compounds will inhibit, delay or reverse carcinogenesis, and can be taken for long periods of time with …

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 …

The Potential Role Of Ledgf/P75 In Prostate Cancer, Tracy Ruth Daniels

Loma Linda University Electronic Theses, Dissertations & Projects

The serum autoantibody repertoire from cancer patients is currently being exploited for the identification of tumor associated antigens (TAA) and the design of TAA arrays. Such arrays would facilitate autoantibody profiling and potentially aid in the serological diagnosis and prognosis of tumors. The goal of this study was to identify and characterize prostate-specific TAA. We observed that while the general frequency and titers of autoantibodies in PCa patients were relatively similar to those in matched controls, significant differences could be detected between the two groups in the autoantibody response to the lens epithelial-derived growth factor p75 (LEDGF/p75). LEDGF/p75 is a …

Effects Of Liposome-Encapsulated Tnf-Alpha And Radiation Against Colon Cancer, Dong Won Kim

Loma Linda University Electronic Theses, Dissertations & Projects

Previous studies have shown that tumor necrosis factor-α (TNF-α) can augment the antitumor effects of radiation, inhibiting tumor progression to a greater extent than either modality alone. However, nonspecific toxicities associated with TNF-α have limited its use as an adjuvant. This limitation is potentially resolved with the encapsulation of TNF-α in sterically stabilized, PEGylated liposomes (STEALTH®). Thus, the overall hypothesis of the research was that the combination of radiation with STEALTH® liposome encapsulated TNF-α (SL-TNF-α) will have greater efficacy and fewer dose-limiting side effects in the LS174T human colorectal tumor xenograft model compared to the combination of free TNF-α and …

Vaccinia Virus-Mediated Glioma Gene Therapy Using P53, Il-2 And Il-12, Bing Chen

Loma Linda University Electronic Theses, Dissertations & Projects

Malignant brain tumors are generally lethal soon after their diagnosis, and the five-year survival rate for the patient is low in spite of neurosurgery, radiation therapy, and/or chemotherapy. Gene therapy has the potential to improve patient survival and quality of life by delivering specific combinations of therapeutic genes directly to the tumor for localized treatment.

We have based our cancer gene therapy for glioma on a highly attenuated variant of the Lister strain of vaccinia virus (VV) which has been proven to be a safe and effective vaccine vector. Other advantages include a wide host range, a strong promoter system, …

Connexin-32 Contributes To Radiation Resistance In Thyroid Follicles, Da-Thao Dinh Tran

Loma Linda University Electronic Theses, Dissertations & Projects

The objective of this study was to examine the role of gap junctions in the radiation resistance of thyroid follicles. The question of whether gap junctional intercellular communication plays an important role in the “contact effect”, wherein cells in direct apposition are more resistant to the damaging effects of radiation, has been debated for years. We used the Fischer rat thyroid cell line (FRTL-5) to carry out our experiments. This thesis is divided into two parts: 1) characterization of gap junctional properties in FRTL-5 cells and, 2) exposure of these cells to radiation.

We found that, unlike primary thyroid cells, …

Study Of The Hiv-1 Gene Regulatory Proteins Tat And Rev By The Two-Hybrid System In Yeast, David Allen Elkins

Loma Linda University Electronic Theses, Dissertations & Projects

Tat and Rev, small proteins encoded by the Human Immunodeficiency Virus type 1 (HIV-1), regulate its pattern of gene expression within infected cells. Tat increases transcription from the integrated pro virus by approximately a thousand-fold; Rev effects a shift in the pattern of splicing of the viral mRNA. Both are likely to interact with cellular proteins in executing their respective functions. Tat has additional activities (including neurotoxicity and inhibition of lymphocyte activation) which may be extraneous to its viral functions.

In order to identify cellular proteins interacting with Tat and Rev, the genes for both were cloned into plasmid vectors …

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 …

The Production And Characterization Of A Monoclonal Antibody To A Naturally Occurring Aminomalonic Acid Epitope And A Comparison With An Antibody To A Synthetically Derived Aminomalonic Acid Epitope, James L. Gulley

Loma Linda University Electronic Theses, Dissertations & Projects

The goal for this project is to undertake the first step in the study of blocking metastasis by a monoclonal antibody. The long range goal of this line of research is to study a novel mechanism for the blocking of tumor metastasis in general and prostatic cancer metastasis in particular. The problem that this addresses is the growing number of cases of prostatic cancer in the increasingly aging male population. This cancer is not lethal unless it metastasizes, yet there is no cure for the metastatic disease. The inherent specificity of a monoclonal antibody combined with the uniqueness of the …

Suppressive Effects Of Transforming Factor-Β And Interleukin-10 On The Cytolytic Activity Of Murine Macrophages And Reversal By Cytokines, Chin-Hung Lin

Loma Linda University Electronic Theses, Dissertations & Projects

In this study, the suppressive effects of transforming growth factor-β (TGF-β) and interleukin-10 (IL-10) on peritoneal macrophage killing of H238 target cells and the potential for reversal of the immunosuppressive effect by IL-4 and interferon-γ (IFN-γ) were investigated. The responsiveness of naive and peptone-activated macrophages was compared. The cytolytic activity for tumor cells of these effector cells was measured by percent lysis of ³H-thymidine labeled Herpes simplex virus type 2-transformed tumor cells (H238). After 18-24 hours of incubation with TGF-β or IL-10, the cytolytic activity of macro-medium alone. The immunosuppressive effect of TGF-β or IL-10 on non-activated macrophages was …

A Flow Cytometric Analysis Of Immunocyte Populations In Peripheral Blood And Pleural Effusions Of Patients With Cancer, Mandy L. Bohn

Loma Linda University Electronic Theses, Dissertations & Projects

Two-color flow cytometric analysis was performed on paired samples of peripheral blood (PB) and pleural effusions (PE) of patients with metastatic malignancies. The purpose of these analyses was to test the hypothesis that there are significant differences in the distribution of immunocyte populations in the PE compared to that of the PB.

The majority of the pleural fluid immunocytes were CD3+ cells. The ratio of CD4+ to CD8+ cells was higher in the PE compared to PB. Levels of CD8+, CD19+ and CD14+ cells were not significantly different in the PE compared to the levels in the PB. CD16+CD56+ cells …

In Vitro Evaluation Of Cancer Patient Immune Responses Following Infusion Of Radiolabeled Murine Monoclonal Antibody, Kelly A. King

Loma Linda University Electronic Theses, Dissertations & Projects

Several monoclonal antibody (MAb) types derived from mice have been developed specifically for the use of targeting human tumors. The specificity of these murine MAb’s for their respective tumor antigens is very high making them potentially good immunotherapeutic agents for cancer treatment and diagnosis. A limiting factor in using these murine MAb’s in patients is the development of human anti-mouse antibody (HAMA). The presence of HAMA may reduce the effectiveness of MAb for tumor targeting. If patient sensitization could be quickly detected following the initial infusion of MAb, then future infusion could be altered or terminated to prevent further sensitization. …