Life Sciences Commons^™

Minibrain And Wings Apart Control Organ Growth And Tissue Patterning Through Downregulation Of Capicua, Liu Yang

Graduate Doctoral Dissertations

The regulation of organ growth is a fundamental aspect of developmental biology. My work uses Drosophila as a model system to understand how the various growth regulators are coordinated. The transcriptional repressor Capicua (Cic) controls tissue patterning and restricts organ growth, and has been recently implicated in several cancers and neurodegenerative diseases. Cic has emerged as a primary sensor of signaling downstream of the receptor tyrosine kinase (RTK)/extracellular signal-regulated kinase (ERK) pathway, but how Cic activity is regulated in different cellular contexts remains poorly understood. In order to identify Cic regulators, I have used affinity purification/mass spectrometry (AP-MS) to study …

Evolution In The Deep Sea: Scales And Mechanisms Of Population Divergence, Amanda E. Glazier

Graduate Doctoral Dissertations

The deep sea is the Earth’s largest ecosystem and harbors a unique and largely endemic fauna. Although most research has focused on the ecological mechanisms that allow coexistence, recent studies have begun to investigate how this remarkable fauna evolved.. My work quantifies geographic patterns of genetic variation and investigates potential mechanisms that shape evolution in the deep ocean.

Bathymetric genetic divergence is common in the deep sea with population structure typically decreasing with depth. The evolutionary mechanisms that underlie these patterns are poorly understood. Geographic patterns of genetic variation indicated that the protobranch bivalve Neilonella salicensis was composed of two …

Analyzing And Modeling The Dysfunction Of Inhibitory Neurons In Alzheimer’S Disease, Carlos Perez, Jokubas Ziburkus, Ghamim Ullah

Physics Faculty Publications

Alzheimer’s disease (AD) is characterized by the abnormal proteolytic processing of amyloid precursor protein, resulting in increased production of a self-aggregating form of beta amyloid (Aβ). Several lines of work on AD patients and transgenic mice with high Aβ levels exhibit altered rhythmicity, aberrant neuronal network activity and hyperexcitability reflected in clusters of hyperactive neurons, and spontaneous epileptic activity. Recent studies highlight that abnormal accumulation of Aβ changes intrinsic properties of inhibitory neurons, which is one of the main reasons underlying the impaired network activity. However, specific cellular mechanisms leading to interneuronal dysfunction are not completely …

Winner's Curse Correction And Variable Thresholding Improve Performance Of Polygenic Risk Modeling Based On Genome-Wide Association Study Summary-Level Data, Jianxin Shi, Ju-Hyun Park, Jubao Duan, Sonja T. Berndt, Winton Moy, Kai Yu, Lei Song, William Wheeler, Xing Hua, Debra Silverman, Montserrat Garcia-Closas, Chao Agnes Hsiung, Jonine D. Figueroa, Victoria K. Cortessis, Nuria Malats, Margaret R. Karagas

Dartmouth Scholarship

Recent heritability analyses have indicated that genome-wide association studies (GWAS) have the potential to improve genetic risk prediction for complex diseases based on polygenic risk score (PRS), a simple modelling technique that can be implemented using summary-level data from the discovery samples. We herein propose modifications to improve the performance of PRS. We introduce threshold-dependent winner’s-curse adjustments for marginal association coefficients that are used to weight the single-nucleotide polymorphisms (SNPs) in PRS. Further, as a way to incorporate external functional/annotation knowledge that could identify subsets of SNPs highly enriched for associations, we propose variable thresholds for SNPs selection. We applied …

Stability Of Cross-Feeding Polymorphisms In Microbial Communities, Ivana Gudelj, Margie Kinnersley, Peter Rashkov, Karen Schmidt, Frank Rosenzweig

Biological Sciences Faculty Publications

Cross-feeding, a relationship wherein one organism consumes metabolites excreted by another, is a ubiquitous feature of natural and clinically-relevant microbial communities and could be a key factor promoting diversity in extreme and/or nutrient-poor environments. However, it remains unclear how readily cross-feeding interactions form, and therefore our ability to predict their emergence is limited. In this paper we developed a mathematical model parameterized using data from the biochemistry and ecology of an E. coli cross-feeding laboratory system. The model accurately captures short-term dynamics of the two competitors that have been observed empirically and we use it to systematically explore the stability …

Cullin-4 Regulates Wingless And Jnk Signaling-Mediated Cell Death In The Drosophila Eye., Meghana Tare, Ankita Sarkar, Shimpi Bedi, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

In all multicellular organisms, the fundamental processes of cell proliferation and cell death are crucial for growth regulation during organogenesis. Strict regulation of cell death is important to maintain tissue homeostasis by affecting processes like regulation of cell number, and elimination of unwanted/unfit cells. The developing Drosophila eye is a versatile model to study patterning and growth, where complex signaling pathways regulate growth and cell survival. However, the molecular mechanisms underlying regulation of these processes is not fully understood. In a gain-of-function screen, we found that misexpression of cullin-4 (cul-4), an ubiquitin ligase, can rescue reduced eye mutant phenotypes. Previously, …

The Replication Initiator Of The Cholera Pathogen’S Second Chromosome Shows Structural Similarity To Plasmid Initiators, Natalia Orlova, Matthew Gerding, Olha Ivashkiv, Paul Dominic B. Olinares, Brian T. Chait, Matthew K. Waldor, David Jeruzalmi

Publications and Research

The conserved DnaA-oriC system is used to initiate replication of primary chromosomes throughout the bacterial kingdom; however, bacteria with multipartite genomes evolved distinct systems to initiate replication of secondary chromosomes. In the cholera pathogen, Vibrio cholerae, and in related species, secondary chromosome replication requires the RctB initiator protein. Here, we show that RctB consists of four domains. The structure of its central two domains resembles that of several plasmid replication initiators. RctB contains at least three DNA binding winged-helix-turn-helix motifs, and mutations within any of these severely compromise biological activity. In the structure, RctB adopts a headto- head dimeric configuration …

Expansion Of The Molecular And Morphological Diversity Of Acanthamoebidae (Centramoebida, Amoebozoa) And Identification Of A Novel Life Cycle Type Within The Group, Alexander Tice, Lora Shadwick, Anna Maria Fiore-Donno, Stefen Geisen, Seungho Kang, Gabriel Schuler, Frederick Spiegel, Katherine Wilkinson, Michael Bonkowski, Kenneth Dumack, Daniel Lahr, Eckhard Voelcker, Steffen Claub, Junling Zhang, Matthew Brown

Faculty Publications, Biological Sciences

Background Acanthamoebidae is a “family” level amoebozoan group composed of the genera Acanthamoeba, Protacanthamoeba, and very recently Luapeleamoeba. This clade of amoebozoans has received considerable attention from the broader scientific community as Acanthamoeba spp. represent both model organisms and human pathogens. While the classical composition of the group (Acanthamoeba + Protacanthamoeba) has been well accepted due to the morphological and ultrastructural similarities of its members, the Acanthamoebidae has never been highly statistically supported in single gene phylogenetic reconstructions of Amoebozoa either by maximum likelihood (ML) or Bayesian analyses. Results Here we show using a phylogenomic approach that the Acanthamoebidae is …

Cytochrome C Can Form A Well-Defined Binding Pocket For Hydrocarbons, Levi J. Mcclelland, Harmen B. Steele, Frank G. Whitby, Tung-Chung Mou, David Holley, J B. Ross, Stephen R. Sprang, Bruce E. Bowler

Biological Sciences Faculty Publications

Cytochrome c can acquire peroxidase activity when it binds to cardiolipin in mitochondrial membranes. The resulting oxygenation of cardiolipin by cytochrome c provides an early signal for the onset of apoptosis. The structure of this enzyme-substrate complex is a matter of considerable debate. We present three structures at 1.7-2.0 Å resolution of a domain-swapped dimer of yeast iso-1-cytochrome c with the detergents, CYMAL-5, CYMAL-6, and ω-undecylenyl-β-d-maltopyranoside, bound in a channel that places the hydrocarbon moieties of these detergents next to the heme. The heme is poised for peroxidase activity with water bound in place of Met80, which serves as the …

Recent Diatoms Reported From The Central United States: Register Of Taxa And Synonyms, Mark E. Eberle

Biological Sciences Faculty Publications

This list of diatoms summarizes information for more than 1000 taxa and synonyms reported in published accounts of collections made in the central United States, principally within the states of Kansas, Nebraska, and Oklahoma, but also including adjacent areas in eastern Colorado and western Missouri. The objective was to provide people working on diatom projects in this region with a base reference to help them assess the results of their research. Records from Master’s theses and references focused on fossil diatoms were not incorporated into this list. Specimens were not examined, so taxa presented here are those reported in the …

Macroinvertebrate Community Composition, Food Web Structure, And Emergence Rate In Neotropical Cloud-Forest Streams In Mindo, Ecuador, Anna M. Harris

Masters Theses

Tropical cloud forest streams are one of the most threatened and understudied ecosystems in the world. Understanding how these ecosystems function is essential for effective conservation. In this study, macroinvertebrate community composition, functional feeding group analysis, ecosystem attributes, and physicochemical parameters were used to evaluate biophysical stream conditions of 3 low-order Neotropical cloud forest streams at Reserva Las Gralarias in Mindo, Ecuador. Additionally, food web structure was analyzed via stable isotope analysis and aquatic insect emergence rate was also examined. As stream size increased from 1st to 3rd order, the macroinvertebrate communities shifted from being collector-gatherer dominated (65.2 to 29.8%, …

Microbial Phytases And Phytate: Exploring Opportunities For Sustainable Phosphorus Management In Agriculture, Nelly P. Balaban, Aliya D. Suleimanova, Lia R. Valeeva, Inna B. Chastukhina, Natalia L. Rudakova, Margarita R. Sharipova, Eugene V. Shakirov

Biological Sciences Faculty Research

Myo-inositol phosphates (phytates) are important biological molecules produced largely by plants to store phosphorus. Phytate is very abundant in many different soils making up a large portion of all soil phosphorus. This review assesses current phytase science from the perspective of its substrate, phytate, by examining the intricate relationship between the phytate-hydrolyzing enzymes and phytate as their substrate. Specifically, we examine available data on phytate’s structural features, distribution in nature and functional roles. The role of phytases and their localization in soil and plant tissues are evaluated. We provide a summary of the current biotechnological advances in using industrial …

Ric-8a, A G Protein Chaperone With Nucleotide Exchange Activity Induces Long-Range Secondary Structure Changes In Gα, Ravi Kant, Baisen Zeng, Celestine J. Thomas, Brian Bothner, Stephen R. Sprang

Biological Sciences Faculty Publications

Cytosolic Ric-8A has guanine nucleotide exchange factor (GEF) activity and is a chaperone for several classes of heterotrimeric G protein α subunits in vertebrates. Using Hydrogen-Deuterium Exchange-Mass Spectrometry (HDX-MS) we show that Ric-8A disrupts the secondary structure of the Gα Ras-like domain that girds the guanine nucleotide-binding site, and destabilizes the interface between the Gαi1 Ras and helical domains, allowing domain separation and nucleotide release. These changes are largely reversed upon binding GTP and dissociation of Ric-8A. HDX-MS identifies a potential Gα interaction site in Ric-8A. Alanine scanning reveals residues crucial for GEF activity within that sequence. HDX confirms that, …

Invasive Species In An Urban Flora: History And Current Status In Indianapolis, Indiana, Rebecca W. Dolan

Rebecca W. Dolan

Invasive plant species are widely appreciated to cause significant ecologic and economic damage in agricultural fields and in natural areas. The presence and impact of invasives in cities is less well documented. This paper characterizes invasive plants in Indianapolis, Indiana. Based on historical records and contemporary accounts, 69 of the 120 species on the official Indiana state list are reported for the city. Most of these plants are native to Asia or Eurasia, with escape from cultivation as the most common mode of introduction. Most have been in the flora of Indianapolis for some time. Eighty percent of Indianapolis’ invasive …

Taxonomic Revision Of Perdita Subgenus Heteroperdita Timberlake (Hymenoptera: Andrenidae), With Descriptions Of Two Ant-Like Males, Zachary M. Portman, John L. Neff, Terry L. Griswold

Zachary Portman

Bioremoval Of Phenol From Aqueous Solutions Using Native Caribbean Seaweed, Abel E. Navarro, Anibal Hernandez-Vega, Md Emran Masud, Loretta M. Roberson, Liz M. Diaz-Vázquez

Publications and Research

Among several Puerto Rican algae, Sargassum sp. (SG) and Chaetomorpha (CM) showed the highest phenol adsorption capacity from aqueous solutions and were used in optimized adsorption batch experiments at room temperature. The effects of pH, adsorbent dose, phenol concentration, salinity and presence of interfering substances were evaluated. Initial solution pH exhibited a strong effect, mainly on the phenol aqueous chemistry; showing the maximum adsorption at pH 10. Sorption isotherm results were modelled according to the Langmuir, Tempkin and Freundlich equations. Isotherm modelling indicated a maximum adsorption capacity (qmax) of 82.10 and 17.7 mg of phenol per gram of SG and …

Molecular Typing And Virulence Analysis Of Multidrug Resistant Klebsiella Pneumoniae Clinical Isolates Recovered From Egyptian Hospitals, Reham Wasfi, Walid F. Elkhatib, Hossam M. Ashour

Molecular Biosciences Faculty Publications

Klebsiella pneumonia infection rates have increased dramatically. Molecular typing and virulence analysis are powerful tools that can shed light on Klebsiella pneumonia infections. Whereas 77.7% (28/36) of clinical isolates indicated multidrug resistant (MDR) patterns, 50% (18/36) indicated carpabenem resistance. Gene prevalence for the AcrAB efflux pump (82.14%) was more than that of the mdtK efflux pump (32.14%) in the MDR isolates. FimH-1 and mrkD genes were prevalent in wound and blood isolates. FimH-1 gene was prevalent in sputum while mrkD gene was prevalent in urine. Serum resistance associated with outer membrane protein coding gene (traT) was found in all blood …

Factors Influencing Swallow Bug (O. Vicarius) Populations Within Cliff Swallows Nests, Paul Mcphail

Ursidae: The Undergraduate Research Journal at the University of Northern Colorado

Hematophagous ectoparasites such as swallow bugs (Oeciacus vicarius) have been shown to have a profound negative impact on infested bird chicks, and one study shows that O. vicarius populations are positively correlated with large colonies. In this study, we investigated the abundance of O. vicarius and other arthropods within Cliff Swallow nests, and performed statistical analysis of the results to find any variables that correlated with O. vicarius population size. We expected the number of O. vicarius would be positively influenced by urban surroundings and large Cliff Swallow colony size, and that samples collected in the fall would be larger …

Sepsis And Hemocyte Loss In Honey Bees (Apis Mellifera) Infected With Serratia Marcescens Strain Sicaria, Nancy L. Burritt, Nicole J. Foss, Eric C. Neeno-Eckwall, James O. Church, Anna M. Hilger, Jacob A. Hildebrand, David M. Warshauer, Nicole T. Perna, James B. Burritt

Biology Faculty Work

Global loss of honey bee colonies is threatening the human food supply. Diverse pathogens reduce honey bee hardiness needed to sustain colonies, especially in winter. We isolated a free-living Gram negative bacillus from hemolymph of worker honey bees (Apis mellifera) found separated from winter clusters. In some hives, greater than 90% of the dying bees detached from the winter cluster were found to contain this bacterium in their hemolymph. Throughout the year, the same organism was rarely found in bees engaged in normal hive activities, but was detected in about half of Varroa destructor mites obtained from colonies that housed …

Vamorolone, A Dissociative Steroidal Compound, Reduces Pro-Inflammatory Cytokine Expression In Glioma Cells And Increases Activity And Survival In A Murine Model Of Cortical Tumor., Elizabeth Wells, Madhuri Kambhampati, Jesse M Damsker, Heather Gordish-Dressman, Sridevi Yadavilli, Oren J Becher, Jamila Gittens, Mojca Stampar, Roger J. Packer, Javad Nazarian

Genomics and Precision Medicine Faculty Publications

Corticosteroids, such as dexamethasone, are routinely used as palliative care in neuro-oncology for their anti-inflammatory benefits, however many patients experience dose limiting side effects caused by glucocorticoid response element (GRE)-mediated transcription. The purpose of this study was to use a murine model to investigate a new steroid alternative, vamorolone, which promises to reduce side effects through dissociating GRE-mediated transcription and NF-κB -mediated anti-inflammatory actions. To compare vamorolone to dexamethasone in reducing pro-inflammatory signals in vitro, murine glioma cells were treated with dexamethasone, vamorolone or vehicle control. Changes in mRNA expression were assessed using the nanostring inflammatory platform. Furthermore, drug …

Comparative Genomic Analysis Of Two Serotype 1/2b Listeria Monocytogenes Isolates From Analogous Environmental Niches Demonstrates The Influence Of Hypervariable Hotspots In Defining Pathogenesis, Aidan Casey, Kieran Jordan, Aidan Coffey, Edward M. Fox, Olivia Mcauliffe

Department of Biological Sciences Publications

The vast majority of clinical human listeriosis cases are caused by serotype 1/2a, 1/2b, 1/2c, and 4b isolates of Listeria monocytogenes. The ability of L. monocytogenes to establish a systemic listeriosis infection within a host organism relies on a combination of genes that are involved in cell recognition, internalization, evasion of host defenses, and in vitro survival and growth. Recently, whole genome sequencing and comparative genomic analysis have proven to be powerful tools for the identification of these virulence-associated genes in L. monocytogenes. In this study, two serotype 1/2b strains of L. monocytogenes with analogous isolation sources, but …

Can Functional Traits Predict Plant Community Response To Global Change?, Sarah Kimball, Jennifer L. Funk, Marko J. Spasojevic, Katharine N. Suding, Scot Parker, Michael K. Goulden

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

One primary goal at the intersection of community ecology and global change biology is to identify functional traits that are useful for predicting plant community response to global change. We used observations of community composition from a long-term field experiment in two adjacent plant communities (grassland and coastal sage shrub) to investigate how nine key plant functional traits were related to altered water and nitrogen availability following fire. We asked whether the functional responses of species found in more than one community type were context dependent and whether community-weighted mean and functional diversity were significantly altered by water and nitrogen …

A Mineralized Alga And Acritarch Dominated Microbiota From The Tully Formation (Givetian) Of Pennsylvania, Usa, John A. Chamberlain Jr., Rebecca B. Chamberlain, James O. Brown

Publications and Research

Sphaeromorphic algal cysts, most probably of the prasinophyte Tasmanites, and acanthomorphic acritarch vesicles, most probably Solisphaeridium, occur in a single 20 cm thick bed of micritic limestone in the lower part of the Middle Devonian (Givetian) Tully Formation near Lock Haven, Pennsylvania. Specimens are composed of authigenic calcite and pyrite crystals about 5–10 µm in length. Some specimens are completely calcitic; some contain both pyrite and calcite; and many are composed totally of pyrite. The microfossils are about 80 to 150 µm in diameter. Many show signs of originally containing a flexible wall composed of at least two layers. Some …

The Vibrio Cholerae Minor Pilin Tcpb Initiates Assembly And Retraction Of The Toxin- Coregulated Pilus, Dixon Ng, Tony Harn, Tuba Altindal, Subramania Kolappan, Jarrad M. Marles, Rajan Lala, Ingrid Spielman, Yang Gao, Caitlyn A. Hauke, Gabriela Kovacikova, Zia Verjee, Ronald K. Taylor, Nicolas Biais, Lisa Craig

Publications and Research

Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent …

Mitigating The Impacts Of Human Land-Use Change On Biodiversity: With A Focus On Large Migratory Herbivores, Kina Rebekah Murphy

Biology ETDs

Land-use change, commercial over-harvesting of species, and climate change are recognized as the main drivers of biodiversity loss. As a result, it is estimated that 30% of the planet’s biodiversity may go extinct by 2050. This dissertation focuses on how to mitigate the impacts of land-use change on biodiversity. I focus on large migratory herbivores because they are among the most heavily impacted by global change due to their large home range requirements. Habitat fragmentation, illegal hunting, and human-wildlife conflicts are among the biggest threats to large herbivores and result from land-use change. For this reason, my first chapter focuses …

Permian Scorpions From The Petrified Forest Of Chemnitz, Germany, Jason A. Dunlop, David A. Legg, Paul L. Selden, Victor Fet, Joerg W. Schneider, Ronny Rößler

Victor Fet

Background: Paleozoic scorpions (Arachnida: Scorpiones) have been widely documented from the Carboniferous Period; which hosts a remarkable assemblage of more than sixty species including both putative stem- and crown-group fossils. By contrast the succeeding Permian Period is almost completely devoid of records, which are currently restricted to a trace fossil from the early Permian of New Mexico, USA and some limb fragments from the late Permian of the Vologda Region, Russia. Results: ?Opsieobuthus tungeri sp. nov. from the Petrified Forest of Chemnitz, Germany represents the first complete body fossils of scorpions from the Permian. Explosive volcanism preserved these remarkable specimens …

Integrating Habitat Suitability Modeling And Radio Telemetry To Describe Habitat Use Of The Western Massasaugas, Sistrurus T. Tergeminus, In Texas, Mitchell R. Barazowski

Biology Theses

Habitat suitability modeling using the software package MaxEnt (Phillips, Anderson, & Schapire, 2006) is a popular method for describing the habitat of rare species. MaxEnt uses “presence only” data to develop models; however presence data are highly skewed towards areas of high detection probability and these areas may not represent the full range of habitat use. Thusly, predictions from models developed using only data from areas with high detection probability may not represent all suitable habitat. This study tested the ability of MaxEnt models developed using three different data sets to accurately describe Western Massasauga (Sistrurus t. tergeminus) habitat at …

The Role Of Diaphanous In Ring Canal Development In Drosophila Melanogaster, Alexandra M. Kindred

Undergraduate Honors Thesis Collection

Infertility is a widespread condition that does not always have a known cause, and for which we often do not have a cure. One potential cause of infertility is defects in gametogenesis, or the formation of sperm and egg. During gametogenesis in most organisms, the developing sperm and egg are connected to each other or to supporting cells through intercellular bridges, allowing transfer of materials between cells. Defects in these connections can lead to infertility. The developing fruit fly egg is an excellent model system to study intercellular bridges, or ring canals. Rich in f-actin and actinbinding proteins, ring canals …

Roles Of Siphon Flows In Suspension Feeding, Kevin Du Clos

Electronic Theses and Dissertations

Benthic marine suspension feeders provide an important link between benthic and pelagic ecosystems. The strength of this link is determined by suspension-feeding rates. Many studies have measured suspension-feeding rates using indirect clearance-rate methods, which are based on the depletion of suspended particles. Direct methods that measure the flow of water itself are less common, but they can be more broadly applied because clearance-rate measurements are affected by properties of the cleared particles. We present pumping rates for three species of suspension feeders, the clams Mya arenaria and Mercenaria mercenaria and the tunicate Ciona intestinalis, calculated using a direct method …

The Association Between Oxidative Stress, Cellular Differentiation And Galectins In Human Promyelocytic Leukemia Cells (Hl-60), James R. Vinnai

Electronic Thesis and Dissertation Repository

Galectins are a group of β-galactoside-binding proteins involved in different cellular processes including stress responses and differentiation. The role and expression of galectins under oxidative stress and during neutrophilic differentiation was examined in HL-60 cells. Galectin gene (LGALS), and galectin protein expression were determined using RT-qPCR and immunoblotting, respectively. Neutrophilic differentiation was measured via a spectrofluorometric assay. DNA methylation and JNK signaling were investigated as galectin regulatory mechanisms. Menadione-induced oxidative stress, DMSO-induced differentiation, DNA hypomethylation and JNK signaling all promoted similar galectin expression profiles. Antioxidant N-acetylcysteine attenuated the menadione-induced galectin expression but only partially attenuated DMSO-induced galectin expression. …