Structural Features Of The Pseudomonas Fluorescens Biofilm Adhesin Lapa Required For Lapg-Dependent Cleavage, Biofilm Formation, And Cell Surface Localization, Chelsea D. Boyd, T. Jarrod Smith, Sofiane El-Kirat-Chatel, Peter D. Newell, Yves F. Dufrêne, George A. O'Toole

Dartmouth Scholarship

The localization of the LapA protein to the cell surface is a key step required by Pseudomonas fluorescens Pf0-1 to irreversibly attach to a surface and form a biofilm. LapA is a member of a diverse family of predicted bacterial adhesins, and although lacking a high degree of sequence similarity, family members do share common predicted domains. Here, using mutational analysis, we determine the significance of each domain feature of LapA in relation to its export and localization to the cell surface and function in biofilm formation. Our previous work showed that the N terminus of LapA is required for …

P53 Maintains Hepatic Cell Identity During Liver Regeneration, Zeynep Hande Coban Akdemir

Dissertations and Theses (Open Access)

p53 MAINTAINS HEPATIC CELL IDENTITY DURING LIVER REGENERATION

Zeynep Hande Coban Akdemir, B.S.,M.A.

Advisory Professor: Michelle Craig Barton, Ph.D.

p53 is a tumor suppressor that has been well studied in tumor-derived, cultured cells. However, its functions in normal proliferating cells and tissues are generally overlooked. We propose that p53 functions during the G1-S transition can be studied in normal, differentiated cells during surgery-induced liver regeneration. Two-thirds partial hepatectomy (PH) of mouse liver offers a unique model to compare p53 functions in regenerating versus sham (control) cells. My hypothesis is that intersection of global expression analyses (microarray and RNA sequencing) and …

Transcriptome Analysis Of Listeria Monocytogenes Exposed To Biocide Stress Reveals A Multi-System Response Involving Cell Wall Synthesis, Sugar Uptake, And Motility, Aidan Casey, Edward M. Fox, Stephan Schmitz-Esser, Aidan Coffey, Olivia Mcauliffe, Kieran Jordan

Department of Biological Sciences Publications

Listeria monocytogenes is a virulent food-borne pathogen most often associated with the consumption of “ready-to-eat” foods. The organism is a common contaminant of food processing plants where it may persist for extended periods of time. A commonly used approach for the control of Listeria monocytogenes in the processing environment is the application of biocides such as quaternary ammonium compounds. In this study, the transcriptomic response of a persistent strain of L. monocytogenes (strain 6179) on exposure to a sub-lethal concentration of the quaternary ammonium compound benzethonium chloride (BZT) was assessed. Using RNA-Seq, gene expression levels were quantified by sequencing …

Gene And Protein Sequence Optimization For High-Level Production Of Fully Active And Aglycosylated Lysostaphin In Pichia Pastoris, Hongliang Zhao, Kristina Blazanovic, Yoonjoo Choi, Chris Bailey-Kellogg, Karl E. Griswold

Dartmouth Scholarship

Lysostaphin represents a promising therapeutic agent for the treatment of staphylococcal infections, in particular those of methicillin-resistant Staphylococcus aureus (MRSA). However, conventional expression systems for the enzyme suffer from various limitations, and there remains a need for an efficient and cost-effective production process to facilitate clinical translation and the development of nonmedical applications. While Pichia pastoris is widely used for high-level production of recombinant proteins, there are two major barriers to the production of lysostaphin in this industrially relevant host: lack of expression from the wild-type lysostaphin gene and aberrant glycosylation of the wild-type protein sequence. The first barrier can …

Egonet: Identification Of Human Disease Ego-Network Modules, Rendong Yang, Yun Bai, Zhaohui Qin, Tianwei Yu

PCOM Scholarly Works

Background: Mining novel biomarkers from gene expression profiles for accurate disease classification is challenging due to small sample size and high noise in gene expression measurements. Several studies have proposed integrated analyses of microarray data and protein-protein interaction (PPI) networks to find diagnostic subnetwork markers. However, the neighborhood relationship among network member genes has not been fully considered by those methods, leaving many potential gene markers unidentified. The main idea of this study is to take full advantage of the biological observation that genes associated with the same or similar diseases commonly reside in the same neighborhood of molecular networks.Results: …

Lineage-Specific Transcriptional Profiles Of Symbiodinium Spp. Unaltered By Heat Stress In A Coral Host, Daniel J. Barshis, Jason T. Ladner, Thomas A. Oliver, Stephen R. Palumbi

Biological Sciences Faculty Publications

Dinoflagellates of the genus Symbiodinium form an endosymbiosis with reef building corals, in which photosynthetically derived nutrients comprise the majority of the coral energy budget. An extraordinary amount of functional and genetic diversity is contained within the coral-associated Symbiodinium, with some phylotypes (i.e., genotypic groupings), conferring enhanced stress tolerance to host corals. Recent advances in DNA sequencing technologies have enabled transcriptome-wide profiling of the stress response of the cnidarian coral host; however, a comprehensive understanding of the molecular response to stress of coral-associated Symbiodinium, as well as differences among physiologically susceptible and tolerant types, remains largely unexplored. Here, …

Genome-Wide Sequencing Of Small Rnas Reveals A Tissue-Specific Loss Of Conserved Microrna Families In Echinococcus Granulosus, Yun Bai, Zhuangzhi Zhang, Lei Jin, Hui Kang, Yongquiang Zhu, Lu Zhang, Xia Li, Fengshou Ma, Li Zhao, Et Al.

PCOM Scholarly Works

Background: MicroRNAs (miRNAs) are important post-transcriptional regulators which control growth and development in eukaryotes. The cestode Echinococcus granulosus has a complex life-cycle involving different development stages but the mechanisms underpinning this development, including the involvement of miRNAs, remain unknown. Results: Using Illumina next generation sequencing technology, we sequenced at the genome-wide level three small RNA populations from the adult, protoscolex and cyst membrane of E. granulosus. A total of 94 pre-miRNA candidates (coding 91 mature miRNAs and 39 miRNA stars) were in silico predicted. Through comparison of expression profiles, we found 42 mature miRNAs and 23 miRNA stars expressed with …

Gene Expression Life History Markers In A Hatchery And A Wild Population Of Young-Of-The-Year Oncorhynchus Mykiss, Ian D. F. Garrett

Dissertations and Theses

Life history within a single species can vary significantly. Many of these differences are associated with varying environmental conditions. Understanding what environmental conditions cue alternate life histories within a single species has been researched extensively. In salmonid fishes, more than almost any other group, varying environmental conditions give rise to individuals within species that take markedly different life history trajectories.

Oncorhynchus mykissis a species of salmonid native to the Pacific Northwest region of North America. This species has two life history forms, anadromous and resident. The anadromous form spends a portion of its life in ocean while the resident life …

Transcription Factor Binding Profiles Reveal Cyclic Expression Of Human Protein-Coding Genes And Non-Coding Rnas, Chao Cheng, Matthew Ung, Gavin D. Grant, Michael L. Whitfield

Dartmouth Scholarship

Cell cycle is a complex and highly supervised process that must proceed with regulatory precision to achieve successful cellular division. Despite the wide application, microarray time course experiments have several limitations in identifying cell cycle genes. We thus propose a computational model to predict human cell cycle genes based on transcription factor (TF) binding and regulatory motif information in their promoters. We utilize ENCODE ChIP-seq data and motif information as predictors to discriminate cell cycle against non-cell cycle genes. Our results show that both the trans- TF features and the cis- motif features are predictive of cell cycle genes, and …

Patterns Of Gene Expression From Human Costal Cartilage In Relation To The Chest Wall Deformity Pectus Carinatum, Janna E. Grubbs

Biological Sciences Theses & Dissertations

Cartilage deformities within the human chest wall, specifically pectus excavatum (PE) and pectus carinatum (PC) are common (1/400-1/1000) and yet, despite their clinical significance, are some of the least studied disorders pertaining to cartilage [1]. The costal cartilage connecting "false ribs" 8-10 to the sternum is often abnormally grown and can lead to formation of a severely sunken "funnel" chest (PE) or push outwards to form a "pigeon" chest (PC). Both conditions can have impact on the diaphragm, heart, lungs, and psychological function. An established ratio of PE and PC in males to females is 4:1, indicating a sex-linked male …

Comparison Of Th1 Cytokines And T Cell Markers Gene Expressions Between Virulent And An Attenuated Eiav Vaccine Strain, Talia R. Henkle

Lewis Honors College Capstone Collection

The equine infectious anemia virus (EIAV) is closely related to HIV and has been used as a model to identify protective mechanisms against lentivirus infection. In horses, EIA infection progresses for about a year before infected horses manage to control virus replication. This naturally-gained protection is absolutely dependent on active immune responses as evidenced by the fact that immunosuppressive drugs can induce the recurrence of disease. As the resolution of initial viremia correlates with the appearance of virus specific cytotoxic T lymphocytes (CTL), we believe that cellular immune responses play a key role in controlling EIAV in the horse. In …

Understanding Osmoregulation And Immunity In Heteromyid Rodents Through Insights Gained From Rna-Seq, Nicholas John Marra

Open Access Dissertations

Understanding the genetic basis of adaptation is one of the central questions of evolutionary genetics. In the face of selective pressure, individuals with adaptive phenotypes survive and pass on their beneficial alleles that conferred this fitness advantage. Over sufficient time scales and under strong selection, differences accumulate between taxa in the form of physical and/or behavioral traits that have been shaped differently. By looking at the transcriptomes of related taxa we can identify sequence and regulatory differences that represent molecular signatures of these different selection regimes. When we study these differences between taxa that have evolved under opposing selective forces …

Axolotl Paedomorphosis: A Comparison Of Juvenile, Metamorphic, And Paedomorphic Ambystoma Mexicanum Brain Gene Transcription, Carlena Johnson

Theses and Dissertations--Biology

Unlike many amphibians, the paedomorphic axolotl (Ambystoma mexicanum) rarely undergoes external morphological changes indicative of metamorphosis. However, internally, some axolotl tissues undergo cryptic metamorphic changes. A previous study examined interspecific patterns of larval brain gene expression and found that these species exhibited unique temporal expression patterns that were hypothesized to be morph specific. This thesis tested this hypothesis by examining differences in brain gene expression between juvenile (JUV), paedomorphic (PAED), and metamorphic (MET) axolotls. I identified 828 genes that were expressed differently between JUV, PAED, and MET. Expression estimates from JUV were compared to estimates from PAED and …

Topical Gene Electrotransfer To The Epidermis Of Hairless Guinea Pig By Non-Invasive Multielectrode Array, Sigi Guo, Annelise L. Israel, Gaurav Basu, Amy Donate, Richard Heller

Bioelectrics Publications

Topical gene delivery to the epidermis has the potential to be an effective therapy for skin disorders, cutaneous cancers, vaccinations and systemic metabolic diseases. Previously, we reported on a non-invasive multielectrode array (MEA) that efficiently delivered plasmid DNA and enhanced expression to the skin of several animal models by in vivo gene electrotransfer. Here, we characterized plasmid DNA delivery with the MEA in a hairless guinea pig model, which has a similar histology and structure to human skin. Significant elevation of gene expression up to 4 logs was achieved with intradermal DNA administration followed by topical non-invasive skin gene electrotransfer. …

Multifactorial Patterns Of Gene Expression In Colonic Epithelial Cells Predict Disease Phenotypes In Experimental Colitis, Aubrey Leigh Frantz, Maria E. C. Bruno, Eric William Rogier, Halide Tuna, Donald A. Cohen, Subbarao Bondada, Ralph Lakshman Chelvarajan, J. Anthony Brandon, C. Darrell Jennings, Charlotte S. Kaetzel

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Background— The pathogenesis of inflammatory bowel disease (IBD) is complex and the need to identify molecular biomarkers is critical. Epithelial cells play a central role in maintaining intestinal homeostasis. We previously identified five “signature” biomarkers in colonic epithelial cells (CEC) that are predictive of disease phenotype in Crohn's disease. Here we investigate the ability of CEC biomarkers to define the mechanism and severity of intestinal inflammation.

Methods— We analyzed the expression of RelA, A20, pIgR, tumor necrosis factor (TNF), and macrophage inflammatory protein (MIP)-2 in CEC of mice with dextran sodium sulfate (DSS) acute colitis or T-cell-mediated chronic colitis. …

Genomics Of Mature And Immature Olfactory Sensory Neurons, Melissa D. Nickell, Patrick Breheny, Arnold J. Stromberg, Timothy S. Mcclintock

Physiology Faculty Publications

The continuous replacement of neurons in the olfactory epithelium provides an advantageous model for investigating neuronal differentiation and maturation. By calculating the relative enrichment of every mRNA detected in samples of mature mouse olfactory sensory neurons (OSNs), immature OSNs, and the residual population of neighboring cell types, and then comparing these ratios against the known expression patterns of >300 genes, enrichment criteria that accurately predicted the OSN expression patterns of nearly all genes were determined. We identified 847 immature OSN-specific and 691 mature OSN-specific genes. The control of gene expression by chromatin modification and transcription factors, and neurite growth, protein …

Hypoxia-Sensitive Gene Expression In The Gastrocnemius Muscle Following Chronic Hind Limb Ischemia, Andrew Tilton

Biological Sciences

Chronic ischemia, caused by the formation atherosclerotic plaque occlusions in major conduit arteries, is the leading cause of morbidity and mortality in western societies. Vascular remodeling can help compensate for the adverse effects of atherosclerotic plaque formation. Vascular remodeling relies heavily on vascular endothelial growth factor (VEGF), a critical protein that contributes to all forms of vascular formation and remodeling including angiogenesis, arteriogenesisand vasculogenesis. VEGF itself is up-regulated by the transcription factor, hypoxia inducible factor 1 alpha (HIF-1α), which becomes activated in low oxygen environments.

Through the use of animal chronic hindlimb ischemia models, these genes can be evaluated as …

Selfish Little Circles: Transmission Bias And Evolution Of Large Deletion-Bearing Mitochondrial Dna In Caenorhabditis Briggsae Nematodes, Katie A. Clark, Dana K. Howe, Kristin Gafner, Danika Kusuma, Sita Ping, Suzanne Estes

Biology Faculty Publications and Presentations

Selfish DNA poses a significant challenge to genome stability and organismal fitness in diverse eukaryotic lineages. Although selfish mitochondrial DNA (mtDNA) has known associations with cytoplasmic male sterility in numerous gynodioecious plant species and is manifested as petite mutants in experimental yeast lab populations, examples of selfish mtDNA in animals are less common. We analyzed the inheritance and evolution of mitochondrial DNA bearing large heteroplasmic deletions including nad5 gene sequences (nad5Δ mtDNA), in the nematode Caenorhabditis briggsae. The deletion is widespread in C. briggsae natural populations and is associated with deleterious organismal effects. We studied the inheritance patterns of nad5Δ …

Desert Hedgehog Is A Mammal-Specific Gene Expressed During Testicular And Ovarian Development In A Marsupial, William A. O'Hara

Master's Theses

Desert hedgehog (DHH) belongs to the hedgehog gene family that act as secreted intercellular signal transducers. DHH is an essential morphogen for normal testicular development and function in both mice and humans but is not present in the avian lineage. Like other hedgehog proteins, DHH signals through the patched (PTCH) receptors 1 and 2. Here we examine the expression and protein distribution of DHH, PTCH1 and PTCH2 in the developing testes of a marsupial mammal (the tammar wallaby) to determine whether DHH signalling is a conserved factor in gonadal development in all therian mammals.

Genome-Wide Expression Analysis In Down Syndrome: Insight Into Immunodeficiency, Chong Li, Lei Jin, Yun Bai, Qimin Chen, Lijun Fu, Minjun Yang, Huasheng Xiao, Guoping Zhao, Shengyue Wang

PCOM Scholarly Works

Down syndrome (DS) is caused by triplication of Human chromosome 21 (Hsa21) and associated with an array of deleterious phenotypes, including mental retardation, heart defects and immunodeficiency. Genome-wide expression patterns of uncultured peripheral blood cells are useful to understanding of DS-associated immune dysfunction. We used a Human Exon microarray to characterize gene expression in uncultured peripheral blood cells derived from DS individuals and age-matched controls from two age groups: neonate (N) and child (C). A total of 174 transcript clusters (gene-level) with eight located on Hsa21 in N group and 383 transcript clusters including 56 on Hsa21 in C group …

Transcriptome Analysis Of Glue Secretion In Drosophila, William Mccurdy, Pawel Parafianowicz, Andrew Andres

McNair Poster Presentations

Steroid hormones control important developmental and physiological responses in animals, including humans. It is known that when a cell is exposed to a steroid hormone, there is an immediate change in the genes that are expressed into proteins. Of notable importance is steroid regulation in the salivary glands of larval Drosophila melanogaster and the corresponding physiological responses that are governed by treatment with the conserved insect steroid, 20-hydroxyecdysone (20E). Exposure to the steroid hormone 20E causes a change in gene expression that facilitates the secretion of glue glycoproteins from inside the cells into the lumen of the tissue. Altered gene …

A Shared Gene Expression Signature In Mouse Models Of Ebv-Associated And Non-Ebv-Associated Burkitt Lymphoma, Kathryn T. Bieging, Kamonwan Fish, Subbarao Bondada, Richard Longnecker

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The link between EBV infection and Burkitt lymphoma (BL) is strong, but the mechanism underlying that link has been elusive. We have developed a mouse model for EBV-associated BL in which LMP2A, an EBV latency protein, and MYC are expressed in B cells. Our model has demonstrated the ability of LMP2A to accelerate tumor onset, increase spleen size, and bypass p53 inactivation. Here we describe the results of total gene expression analysis of tumor and pretumor B cells from our transgenic mouse model. Although we see many phenotypic differences and changes in gene expression in pretumor B cells, the transcriptional …

Exploring The Effects Of Hypoxia On Sulfate Reducing Anaerobes, Annaliese K. Jones

Senior Honors Projects

Exploring the Effects of Hypoxia on Sulfate Reducing Anaerobes

Annaliese K. Jones

Sponsor: Bethany Jenkins, Cell and Molecular Biology

As a student about to graduate with a degree in Biological Sciences, I find myself faced with the need to find my own independent research interests and scientific voice. As a result of my interests in the fields of both microbiology and ecology, I am drawn to questions surrounding the role and behavior of microorganisms in the environment. With climate change being an issue capturing the attention of a large portion of the scientific community, I have chosen to focus my …

The Nuclear Pore Complex Mediates Binding Of The Mig1 Repressor To Target Promoters, Nayan J. Sarma, Thomas D. Buford, Terry Haley, Kellie Barbara-Haley, George M. Santangelo, Kristine A. Willis

Faculty Publications

All eukaryotic cells alter their transcriptional program in response to the sugar glucose. In Saccharomyces cerevisiae, the best-studied downstream effector of this response is the glucose-regulated repressor Mig1. We show here that nuclear pore complexes also contribute to glucose-regulated gene expression. NPCs participate in glucose-responsive repression by physically interacting with Mig1 and mediating its function independently of nucleocytoplasmic transport. Surprisingly, despite its abundant presence in the nucleus of glucose-grown nup120Δ or nup133Δ cells, Mig1 has lost its ability to interact with target promoters. The glucose repression defect in the absence of these nuclear pore components therefore appears …

Ldoc1, A Novel Biomarker Of Prognosis In Chronic Lymphocytic Leukemia, Hatice Duzkale

Dissertations and Theses (Open Access)

In chronic lymphocytic leukemia (CLL), one of the best predictors of outcome is the somatic mutation status of the immunoglobulin heavy chain variable region (IGHV) genes. Patients whose CLL cells have unmutated IGHV genes have a median survival of 8 years; those with mutated IGHV genes have a median survival of 25 years. To identify new prognostic biomarkers and molecular targets for therapy in untreated CLL patients, we reanalyzed the raw data from four published gene expression profiling microarray studies. Of 88 candidate biomarkers associated with IGHV somatic mutation status, we identified LDOC1 (Leucine Zipper, Down-regulated in Cancer 1), as …

Molecular Correlates Of Social Dominance: A Novel Role For Ependymin In Aggression, Lynne U. Sneddon, Rupert Schmidt, Yongxiang Fang, Andrew R. Cossins

Ethology Collection

Theoretical and empirical studies have sought to explain the formation and maintenance of social relationships within groups. The resulting dominance hierarchies have significant fitness and survival consequences dependent upon social status. We hypothesised that each position or rank within a group has a distinctive brain gene expression profile that correlates with behavioural phenotype. Furthermore, transitions in rank position should determine which genes shift in expression concurrent with the new dominance status. We used a custom cDNA microarray to profile brain transcript expression in a model species, the rainbow trout, which forms tractable linear hierarchies. Dominant, subdominant and submissive individuals had …

Linear Methods For Analysis And Quality Control Of Relative Expression Ratios From Quantitative Real-Time Polymerase Chain Reaction Experiments, Robert B. Page, Arnold J. Stromberg

Biology Faculty Publications

Relative expression quantitative real-time polymerase chain reaction (RT-qPCR) experiments are a common means of estimating transcript abundances across biological groups and experimental treatments. One of the most frequently used expression measures that results from such experiments is the relative expression ratio (R_E), which describes expression in experimental samples (i.e., RNA isolated from organisms, tissues, and/or cells that were exposed to one or more experimental or nonbaseline condition) in terms of fold change relative to calibrator samples (i.e., RNA isolated from organisms, tissues, and/or cells that were exposed to a control or baseline condition). Over the past decade, several …

Help3 Directly Modulates The Expression Of Hsp70 Gene In Hela Cells Via Hat Activity, Fen Li, Jixian Ma, Yu Ma, Yanyan Hu, Shuhuan Tian, Richard E. White, Guichun Han

PCOM Scholarly Works

Human Elongator complex, which plays a key role in transcript elongation in vitro assay, is incredibly similar in either components or function to its yeast counterpart. However, there are only a few studies focusing on its target gene characterization in vivo. We studied the effect of down-regulation of the human elongation protein 3 (hELP3) on the expression of HSP70 through antisense strategy. Transfecting antisense plasmid p1107 into HeLa cells highly suppressed hELP3 expression, and substantially reduced expression of HSP70 mRNA and protein. Furthermore, chromatin immunoprecipitation assay (ChIP Assay) revealed that hElp3 participates in the transcription elongation of HSPA1A in HeLa …

Improving Gene Expression Data Interpretation By Finding Latent Factors That Co-Regulate Gene Modules With Clinical Factors, Tianwei Yu, Yun Bai

PCOM Scholarly Works

Background: In the analysis of high-throughput data with a clinical outcome, researchers mostly focus on genes/proteins that show first-order relations with the clinical outcome. While this approach yields biomarkers and biological mechanisms that are easily interpretable, it may miss information that is important to the understanding of disease mechanism and/or treatment response. Here we test the hypothesis that unobserved factors can be mobilized by the living system to coordinate the response to the clinical factors.Results: We developed a computational method named Guided Latent Factor Discovery (GLFD) to identify hidden factors that act in combination with the observed clinical factors to …

Capturing Changes In Gene Expression Dynamics By Gene Set Differential Coordination Analysis, Tianwei Yu, Yun Bai

PCOM Scholarly Works

Analyzing gene expression data at the gene set level greatly improves feature extraction and data interpretation. Currently most efforts in gene set analysis are focused on differential expression analysis - finding gene sets whose genes show first-order relationship with the clinical outcome. However the regulation of the biological system is complex, and much of the change in gene expression dynamics do not manifest in the form of differential expression. At the gene set level, capturing the change in expression dynamics is difficult due to the complexity and heterogeneity of the gene sets. Here we report a systematic approach to detect …