Molecular Genetics Commons^™

Geographic Variation In Malarial Parasite Lineages In The Common Yellowthroat (Geothlypis Trichas), K. M. Pagenkopp, John Klicka, K. L. Durrant, J. C. Garvin, R. C. Fleischer

Ornithology Program (HRC)

Our current understanding of migration routes of many birds is limited and researchers have employed various methods to determine migratory patterns. Recently, parasites have been used to track migratory birds. The objective of this study was to determine whether haemosporidian parasite lineages detect significant geographic structure in common yellowthroats (Geothlypis trichas). We examined liver tissue or blood from 552 birds sampled from multiple locations throughout the continental United States, southern Canada, and the Bahamas. We found a 52.7% overall prevalence of haematozoan infection. We identified 86.1% of these infections to genus: 81% were Plasmodium; 5% were Haemoproteus …

Evolutionary Genetics Of Tetrodotoxin (Ttx) Resistance In Snakes: Tracking A Feeding Adaptation From Populations Through Clades, Chris R. Feldman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding the nature of adaptive evolution has been the recent focus of research detailing the genetic basis of adaptation and theoretical work describing the mechanics of adaptive evolution. Nevertheless, key questions regarding the process of adaptive evolution remain. Ultimately, a detailed description of the ecological context, evolutionary history, and genetic basis of adaptations is required to advance our understanding of adaptive evolution. To address some of the contemporary issues surrounding adaptive evolution, I examine phenotypic and genotypic changes in a snake feeding adaptation.

Adaptations can arise through fixation of novel mutations or recruitment of existing variation. Some populations of the …

Transcriptional Response Of Mexican Axolotls To Ambystoma Tigrinum Virus (Atv) Infection, Jennifer D. Cotter, Andrew Storfer, Robert B. Page, Christopher K. Beachy, S. Randal Voss

Biology Faculty Publications

Background

Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma tigrinum virus (ATV).

Result

At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust …

Accelerated High Fidelity Prion Amplification Within And Across Prion Species Barriers, Kristi M. Green, Joaquín Castilla, Tanya S. Seward, Dana L. Napier, Jean E. Jewell, Claudio Soto, Glenn C. Telling

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Experimental obstacles have impeded our ability to study prion transmission within and, more particularly, between species. Here, we used cervid prion protein expressed in brain extracts of transgenic mice, referred to as Tg(CerPrP), as a substrate for in vitro generation of chronic wasting disease (CWD) prions by protein misfolding cyclic amplification (PMCA). Characterization of this infectivity in Tg(CerPrP) mice demonstrated that serial PMCA resulted in the high fidelity amplification of CWD prions with apparently unaltered properties. Using similar methods to amplify mouse RML prions and characterize the resulting novel cervid prions, we show that serial PMCA abrogated a transmission barrier …

Cd5 Plays An Inhibitory Role In The Suppressive Function Of Murine Cd4(+) Cd25(+) T(Reg) Cells., Trivikram Dasu, Joseph E Qualls, Halide Tuna, Chander Raman, Donald A Cohen, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

A subset of CD4(+) T cells, the CD4(+) CD25(+) regulatory T (T(reg)) cells in the lymphoid organs and peripheral blood are known to possess suppressive function. Previous in vitro and in vivo studies have indicated that T cell receptor (TCR) signal is required for development of such 'natural regulatory (T(reg)) cells' and for activation of the effector function of CD4(+) CD25(+) regulatory T cells. CD5 is a cell surface molecule present on all T cells and a subtype of B lymphocytes, the B-1 cells, primarily localized to coelomic cavities, Peyer's patches, tonsils and spleen. CD5 acts as a negative regulator …

Cd5 Plays An Inhibitory Role In The Suppressive Function Of Murine Cd4+ Cd25+ TReg Cells, Trivikram Dasu, Joseph E. Qualls, Halide Tuna, Chander Raman, Donald A. Cohen, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

A subset of CD4⁺ T cells, the CD4⁺ CD25⁺ regulatory T (T_reg) cells in the lymphoid organs and peripheral blood are known to possess suppressive function. Previous in vitro and in vivo studies have indicated that T cell receptor (TCR) signal is required for development of such ‘natural regulatory (T_reg) cells’ and for activation of the effector function of CD4⁺ CD25⁺ regulatory T cells. CD5 is a cell surface molecule present on all T cells and a subtype of B lymphocytes, the B-1 cells, primarily localized to coelomic cavities, Peyer's patches, …

Expression Of Thor Does Not Increase Desiccation Resistance In Drosophila Melanogaster, Robert L. Kobey, Deborah K. Hoshizaki, Allen G. Gibbs

Undergraduate Research Opportunities Program (UROP)

Using microarray analysis of Drosophila melanogaster, the Gibbs lab has identified several hundred candidate genes that may be involved in desiccation resistance. One of these genes is Thor, an important downstream target of the TOR/insulin signaling pathway. Preliminary results confirm that Thor plays a role in desiccation resistance. Further research will be needed to verify these results and understand the mechanism by which Thor increases desiccation resistance. This research will also serve as a proof-of-principle for testing microarray-derived hypotheses.

A previous microarray analysis found evidence that down-regulation of protein synthesis might be a cellular response to desiccation through the up-regulation …

Construction Of A Thif Genetic Disruption In Bacillus Subtilis, Kathleen Bradley, Christine Pybus, Ronald Yasbin, Eduardo Robleto

Undergraduate Research Opportunities Program (UROP)

The goal of our research is to determine whether the level of transcription of a gene is correlated with the level of mutation in that gene. One factor involved in the mutability of a transcribed gene is the ability of the single stranded DNA to form secondary stem loop structures (SLS), in the wake of the transcription bubble, that contain unpaired mutable bases. We are interested in correlating the levels of mutation with transcription in the thiF gene, which is predicted by bioinformatic analysis to be highly mutable. To achieve this goal, Kathleen will first construct a non-polar thiF genetic …

Constructing An Argf- Strain Of Bacillus Subtilis, Allison Faucher, Christine Pybus, Ronald E. Yasbin, Eduardo A. Robleto

Undergraduate Research Opportunities Program (UROP)

The goal of our research is to determine whether the level of transcription of a gene is correlated with the level of mutation in that gene. One factor involved in the mutability of a transcribed gene is the ability of the single stranded DNA to form secondary stem loop structures (SLS), in the wake of the transcription bubble, that contain unpaired mutable bases. We are interested in correlating the levels of mutation with transcription in the argF gene, which is predicted by bioinformatic analysis to be highly mutable. To achieve this goal, Allison will first construct a non-polar argF genetic …

Decoding The Protein Interaction Network - An Approach Integrating Biology And Math, Ryan Huang, Lingkun Gu, Qingxi J. Shen

Undergraduate Research Opportunities Program (UROP)

The WRKY super family is known to play a major role during the plant stress response and development. My project focuses on the protein-protein interaction of an Oryzasativa (rice) transcription factor, OsWRKY71 which functions as the repressor of gibberellins signaling pathway. Previous literature revealed that OsWRKY71 can interact with itself or OsWRKY51 to form dimmers by using bimolecular fluorescence complementation (BiFC). To confirm this result, we use yeast two-hybrid system. As our data showed, OsWRKY71 seems to suppress the reporter gene expression of the conventional yeast two-hybrid system, so we use a modified yeast two-hybrid, Mating-based Split Ubiquitin System (MbSUS). …

Oxidative Stress-Mediated Anticancer Activity Of Novel Ahr Modulators Af & 5f203, Lancelot S. Mclean

Loma Linda University Electronic Theses, Dissertations & Projects

Estrogen receptor positive (ER+) breast cancer tends to respond to anti-estrogen agents such as Tamoxifen. Approximately 40% of ER+ breast cancer is resistant to these agents and those that initially respond often acquire resistance. Estrogen receptor negative (ER-) breast cancer remains largely unresponsive to these agents. It is therefore vital to discover drugs that are potent in both forms of breast cancer. Aminoflavone, (5-amino-2, 3-fluorophenyl)-6,8-difluoro-7-methyl-4H-l-benzopyran-4-one; AF; NSC 686288) and 5F203, (2-[-Amino-3-methy phenyl]-5-flurobenzothiazole) are novel anticancer candidate agents that display potent in vitro and in vivo anti-proliferative activity against select human tumor cells with a unique anticancer activity profile in the …

Novel Binding Domains Mediate Binding Of Hpv 16 E6 To Fadd And Procaspase 8, Sandy S. Tungteakkhun

Loma Linda University Electronic Theses, Dissertations & Projects

To evade the host response to infection, viruses have developed means to survive and propagate. HPV 16, a causative agent of cervical cancer and of some cases of oropharyngeal cancers, is one example. We have reported that the early viral protein E6 binds to proteins necessary for propagation of the apoptotic signal following receptor/ligand interactions, such as those mediated by FADD DED and procaspase 8 DED. E6 expression leads to the dose-dependent accelerated degradation of FADD and the protection of E6-expressing cells from Fas-induced apoptosis. Surprisingly, the splice isoforms of E6, E6_large and E6*, affect the stability of procaspase …

Mechanisms Of T Helper Cell Modulation In A Simulated Space Radiation Environment, Asma Rizvi

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure to solar particle events (SPEs) poses the most serious threat to astronaut health. Due to this radiation environment, exploration of the solar system beyond Earth’s orbit entails many risks for the crew on these deep space missions. Depression or dysfunction of the immune system is a major concern due to its high radio-sensitivity; potential consequences include overwhelming infection, development of cancer, fibrosis, and poor wound healing. Astronauts are also exposed to low dose/low dose rate (LDR) radiation. A three month stay at the international space station exposes them to ~ 0.05 Gy of radiation.

C57BL/6 mice received LDR gamma-radiation …

Effect Of Thyroid Hormone Concentration On The Transcriptional Response Underlying Induced Metamorphosis In The Mexican Axolotl (Ambystoma), Robert B. Page, Stephen R. Voss, Amy K. Samuels, Jeramiah J. Smith, Srikrishna Putta, Christopher K. Beachy

Biology Faculty Publications

Background

Thyroid hormones (TH) induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T₄). We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum) using 5 and 50 nM T₄, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28), and used microarray analysis to quantify mRNA abundances.

Results

Individuals reared in the higher T₄ concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by …

Historic Genetic Structuring And Paraphyly Within The Great-Tailed Grackle, Jeffrey M. Dacosta, Walter Wehtje, John Klicka

Ornithology Program (HRC)

The Great-tailed Grackle (Quiscalus mexicanus) and Boat-tailed Grackle (Q. major) are sister species that have expanded their ranges during historical times. This expansion has created an area of sympatry between these species in Texas and Louisiana, and between distinctive Great-tailed Grackle subspecies in the southwestern United States and northern Mexico. We investigated the evolutionary histories of both species using mitochondrial DNA sequence data and modern phylogenetic methods. Our results reveal genetic structure within Great-tailed, but not Boat-tailed Grackles. Great-tailed Grackles are separated into two clades, but range expansion in the north has led to secondary contact …

Optimizing Qpcr For The Quantification Of Periodontal Pathogens In A Complex Plaque Biofilm, Sreenatha S. Kirakodu, M. Govindaswami, Michael John Novak, Jeffrey L. Ebersole, Karen F. Novak

Center for Oral Health Research Faculty Publications

Quantitative PCR (qPCR) has recently been used to quantify microorganisms in complex communities, including dental plaque biofilms. However, there is variability in the qPCR protocols being used. This study was designed to evaluate the validity of two of these variables with the intent of developing a more standardized qPCR protocol. The two variables evaluated were (1) the use of DNA content versus actual cell counts to estimate bacterial numbers in mixed plaque samples and (2) the effectiveness of three different universal primers versus species specific primers in amplifying specific target pathogens in these samples. Results lead to the development of …

Molecular Evolution Of The Cytochrome C Oxidase Subunit 5a Gene In Primates, Monica Uddin, Juan C. Opazo, Derek E. Wildman, Chet C. Sherwood, Patrick R. Hof, Morris Goodman, Lawrence I. Grossman

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Many electron transport chain (ETC) genes show accelerated rates of nonsynonymous nucleotide substitutions in anthropoid primate lineages, yet in non-anthropoid lineages the ETC proteins are typically highly conserved. Here, we test the hypothesis that COX5A, the ETC gene that encodes cytochrome c oxidase subunit 5A, shows a pattern of anthropoid-specific adaptive evolution, and investigate the distribution of this protein in catarrhine brains.

Results

In a dataset comprising 29 vertebrate taxa, including representatives from all major groups of primates, there is nearly 100% conservation of the COX5A amino acid sequence among extant, non-anthropoid placental mammals. The most recent common …

1, Structural And Functional Studies Of Human Replication Protein A; 2 Dna Damage Responses And Dna Repair Defects In Laminopathy-Based Premature Aging., Yiyong Liu

Electronic Theses and Dissertations

The genome of mammalian cells is under constant attack from DNA-damaging agents. To maintain genomic integrity, cells activate an array of pathways primarily consisting of DNA repair and DNA damage checkpoints. Human replication protein A (RPA), a single-stranded DNA (ssDNA) binding protein, is essential for almost all DNA metabolic pathways. However, the role of RPA in nucleotide excision repair (NER), a DNA repair pathway for removing bulky DNA lesions, remains elusive. In this study, the binding of RPA to a battery of well-defined ssDNA substrates has been systematically examined using fluorescence spectroscopy. The results showed that RPA has a lower …

Mechanism Of Transcriptional Regulation Of C-Reactive Protein Gene Expression., Bhavya Voleti

Electronic Theses and Dissertations

C-reactive protein (CRP) is an acute phase protein produced by hepatocytes whose serum concentration increases in inflammatory conditions including cardiovascular complications. Statins that are used in the treatment of cardiovascular diseases to reduce cholesterol also lower serum CRP levels. In human hepatoma Hep3B cells, CRP is induced in response to cytokines IL-6 and IL-1β. The objective of the study was to determine the mechanism of regulation of CRP gene expression in Hep3B cells in response to cytokines and to determine the effect of statins on CRP expression. Key findings of our research were: 1. IL-1β-activated NF-κB p50/p65 acted synergistically with …

Mechanisms Of Covalent Self-Assembly Of The Azoarcus Ribozyme From Four Fragment Oligonucleotides, Will E. Draper, Eric John Hayden, Niles Lehman

Chemistry Faculty Publications and Presentations

RNA oligomers of length 40–60 nt can self-assemble into covalent versions of the Azoarcus group I intron ribozyme. This process requires a series of recombination reactions in which the internal guide sequence of a nascent catalytic complex makes specific interactions with a complement triplet, CAU, in the oligomers. However, if the CAU were mutated, promiscuous self-assembly may be possible, lessening the dependence on a particular set of oligomer sequences. Here, we assayed whether oligomers containing mutations in the CAU triplet could still self-construct Azoarcus ribozymes. The mutations CAC, CAG, CUU and GAU all inhibited self-assembly to some degree, but did …

Leptospira Interrogans Endostatin-Like Outer Membrane Proteins Bind Host Fibronectin, Laminin And Regulators Of Complement, Brian Stevenson, Henry A. Choy, Marija Pinne, Matthew L. Rotondi, M. Clarke Miller, Edward Demoll, Peter Kraiczy, Anne E. Cooley, Trevor P. Creamer, Marc A. Suchard, Catherine A. Brissette, Ashutosh Verma, David A. Haake

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The pathogenic spirochete Leptospira interrogans disseminates throughout its hosts via the bloodstream, then invades and colonizes a variety of host tissues. Infectious leptospires are resistant to killing by their hosts' alternative pathway of complement-mediated killing, and interact with various host extracellular matrix (ECM) components. The LenA outer surface protein (formerly called LfhA and Lsa24) was previously shown to bind the host ECM component laminin and the complement regulators factor H and factor H-related protein-1. We now demonstrate that infectious L. interrogans contain five additional paralogs of lenA, which we designated lenB, lenC, lenD, lenE and lenF …

Characterization Of The Group Ii Intron Gs. Int1 From The Thermophilic Bacterium Geobacillus Stearothermophilus., Huijing Sun

Electronic Theses and Dissertations

Group II Introns are small segments of DNA that reside in the chromosome of bacteria or the organelles of primitive eukaryotes. These elements have some very interesting properties. First, they are retrotransposons that can move from one location to a new location in DNA via a reverse transcription mechanism. Second, they form a large ribozyme that mediates self-splicing of the intron from pre-mRNA. A Group II Intron type protein with similarity to reverse transcriptase was discovered in the thermophilic bacterium Geobacillus stearothermophilus strain 10 (Vellore et al., 2004, Appl. Environ. Microbiol. 70: 7140-7147). Numerous copies of the intron, …

Comparative Functional Analysis Of Aquaporins/Glyceroporins In Mammals And Anurans, Carissa M. Krane, David L. Goldstein

Biology Faculty Publications

Maintenance of fluid homeostasis is critical to establishing and maintaining normal physiology. The landmark discovery of membrane water channels (aquaporins; AQPs) ushered in a new area in osmoregulatory biology that has drawn from and contributed to diverse branches of biology, from molecular biology and genomics to systems biology and evolution, and from microbial and plant biology to animal and translational physiology. As a result, the study of AQPs provides a unique and integrated backdrop for exploring the relationships between genes and genome systems, the regulation of gene expression, and the physiologic consequences of genetic variation. The wide species distribution of …

Phylogenetics And Phylogeography Of The Artibeus Jamaicensis Complex Based On Cytochrome-B Dna Sequences, Peter A. Larsen, Steven R. Hoofer, Matthew C. Bozeman, Scott C. Pedersen, Hugh H. Genoways, Carleton J. Phillips, Dorothy E. Pumo, Robert J. Baker

University of Nebraska State Museum: Mammalogy Papers

The phylogenetics and phylogeography of the Jamaican fruit-eating bat (Artibeus jamaicensis) were examined based on analysis of DNA sequence variation in the mitochondrial cytochrome-b gene for 176 individuals representing all 13 subspecies of A. jamaicensis (sensu Simmons 2005). Results document that A. jamaicensis (sensu Simmons 2005) comprises 3 monophyletic assemblages that are separated phylogenetically by the presence of A. obscurus, A. lituratus, and . amplus. According to the mitochondrial DNA sequence variation, A. jamaicensis, A. schwartzi, and A. planirostris are appropriate species-level names for these lineages. Haplotypes identifiable as A. jamaicensis were absent east …

Bilateral Gynandromorphy In A White-Ruffed Manakin (Corapipo Altera), Jeffrey M. Dacosta, Garth M. Spellman, John Klicka

Ornithology Program (HRC)

We report bilateral gynandromorphy in a White-ruffed Manakin (Corapipo altera) collected near Santa Fé, Panamá in 2004. The specimen had an oviduct and ovary on the left side and a single testis on the right. The plumage was phenotypically female on the right side and male on the left. The weight and genetic affinity of the specimen were characteristically female. Both Z and W chromosomes were detected in genetic samples from multiple tissue types and toe pads from both feet. This report is a novel record of gynandromorphy in a suboscine passerine.

A Simple And Improved Pcr-Based Technique For White-Tailed Deer (Odocoileus Virginianus) Sex Identification, Alec R. Lindsay Ph. D., Jerrold L. Belant

Faculty Works

We describe a simple single-reaction technique for identifying the sex of white-tailed deer (Odocoileus virginianus) based on the PCR amplification of a zinc-finger intron using one pair of primers. Although Sry-coamplification confirmed sex identities, use of the Sry marker was unnecessary due to dimorphic alleles on the X and Y chromosomes at the zinc-finger locus. Insertions in intron 7 of the Y-linked allele (417 bp) make it nearly twice as long as the X-linked allele (236 bp) and thus the amplification products are easily discernable by simple agarose gel electrophoresis. The relatively short size of these products makes them useful …

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 …

A 368-Base-Pair Cis-Acting Hwp1 Promoter Region, Hcr, Of Candida Albicans Confers Hypha-Specific Gene Regulation And Binds Architectural Transcription Factors Nhp6 And Gcf1p, Samin Kim, Michael J. Wolyniak, Janet F. Staab, Paula Sundstrom

Dartmouth Scholarship

To elucidate the molecular mechanisms controlling the expression of the hypha-specific adhesin gene HWP1 of Candida albicans, its promoter was dissected and analyzed using a green fluorescent protein reporter gene. A 368-bp region, the HWP1 control region (HCR), was critical for activation under hypha-inducing conditions and conferred developmental regulation to a heterologous ENO1 promoter. A more distal region of the promoter served to amplify the level of promoter activation. Using gel mobility shift assays, a 249-bp subregion of HCR, HCRa, was found to bind at least four proteins from crude extracts of yeasts and hyphae with differing binding patterns dependent …

A Molecular Evaluation Of The North American “Grassland” Sparrow Clade, John Klicka, Garth M. Spellman

Ornithology Program (HRC)

Because they share several morphological and ecological characters, the North American sparrow (Emberizidae) genera Ammodramus, Passerculus, and Xenospiza have historically been considered members of a well-defined “grassland” sparrow assemblage. Relationships among the 11 members of this group have been the subject of much taxonomic debate, yet no comprehensive molecular assessment of relationships has been done. We investigated these relationships using mitochondrial DNA sequence data that included complete cytochrome-b and ND2 genes. Phylogenetic reconstructions derived via parsimony, likelihood, and Bayesian methods were congruent. The grassland sparrows, as presently configured, are polyphyletic. Pooecetes gramineus, Amphispiza belli (but not A. …