Digital Commons Network^™

Roles Of Seed Dispersal And Environmental Filters In Establishment Of The Dominant Shrubs: Morella Cerifera And M. Pensylvanica, On An Atlantic Barrier Island, Benjamin Dows

Theses and Dissertations

Patterns of the expansion of woody cover into grasslands on barrier islands of the Virginia coast were investigated. Seed dispersal of the dominant shrub Morella spp., was sampled deploying seed traps (n = 82) throughout a landscape under shrub encroachment pressure on Hog Island, VA. Traps were placed underneath: fruiting Morella, non-fruiting Morella, co-occurring species (Iva frutescens and Baccharis halimifolia) and in grass land, (no shrub cover). Environmental filters that act upon dispersed seeds and subsequently determine establishment patterns were also investigated. Dispersal distribution throughout the encroachment zone was leptokurtic and dispersal among cover types suggest co-occurring shrub species facilitate …

Approaches To Reduce Selection Of Genomic Variants In Human Pluripotent Stem Cell Culture, Marion Riggs

Theses and Dissertations

Optimizing culture conditions that reduce genomic instability in human pluripotent stem cells (hPSCs) is an unmet challenge in the field. Results from our lab and numerous research groups demonstrate that hPSCs are prone to genomic aberrations and single-cell passaging increases the rate of genomic alterations. However, single-cell based passaging maintains advantages for scale-up and standardizing differentiation protocols. In this study, we investigated the problem of genomic instability in hPSC cultures with the goal towards identifying and characterizing candidate genes that could contribute to generation and survival of abnormal hPSCs. Based on microarray analysis, we identify ARHGDIA, located on 17q25, as …

Understanding The Role Of Stylochus Ellipticus As A Predator Of Crassostrea Virginica In Chesapeake Bay Tributaries, Marion Kensey Barker

Theses and Dissertations

Predation may be a key component of the unsuccessful restoration of the Eastern Oyster (Crassostrea virginica), a former keystone species in Chesapeake Bay. Here, I examine the polyclad flatworm Stylochus ellipticus and its potential role as an important predator of C. virginica. Using small-fragment size C. virginica specific DNA primers, oyster DNA was successfully detected in whole organisms homogenates of wild-caught S. ellipticus individuals. Of the 1,575 individuals tested, 68.1% tested positive, thus predation occurred. Predation did not appear to be affected by salinity or temperature; however, season did appear to have an effect on both predation and S. ellipticus …

Planar Cell Polarity And Neurodevelopment, Simon Sun

Theses and Dissertations

Planar cell polarity (PCP) is a developmental signaling mechanism that establishes a polarity within the plane of an epithelium. PCP has been shown to play a role in guiding numerous neurodevelopmental processes such as convergent extension, neuron migration, and axon pathfinding. Certain commissural neurons in the dorsal spinal cord make a series of guidance decisions en route to the brain: first, a ventral projection along the D-V axis, followed by a midline crossing, and after exiting the floorplate, a dorso-anterior turn along the A-P axis. Here, we provide in vivo evidence that the axons of the Commissural Primary Ascending (CoPAs) …

A Passive Acoustic And Experimental Study Of Juvenile Blue Catfish, Ictalurus Furcatus, Sound Production And Agnostic Behavior In The Tidal Freshwater James River, Laura Morgan

Theses and Dissertations

Blue catfish, Ictalurus furcatus, are an invasive species in the James River, VA. They produce stridulation sounds and passive acoustic monitoring may prove useful in locating and monitoring their populations. Little is known about their behavior, therefore my goal was to examine agonistic behavior and the use of sound in defending a territory. This thesis consists of two manuscripts: 1) A passive acoustic study of the tidal freshwater James River, 2) An experimental study of agonistic behavior in juvenile Blue catfish, Ictalurus furcatus. The first study showed that three sounds (click, run croak) occurred more often in warmer months than …

Benthic Macroinvertebrate Subsampling Effort And Taxonomic Resolution For Bioassessments Of Streams In The James River Watershed Of Virginia, Laurel Williams

Theses and Dissertations

Benthic macroinvertebrate diversity influences stream food web dynamics, nutrient cycling and material exchange between the benthos and the water column. Stream bioassessment has moved to the forefront of water quality monitoring in terms of benthic macroinvertebrate diversity in the recent past. The objectives of this study were to determine optimum subsample size and level of taxonomic resolution necessary to accurately and precisely describe macroinvertebrate diversity in streams flowing in the Piedmont province of the James River watershed in Virginia. Forty-nine sampling sites were selected from streams within the Piedmont Physiographic Province of the James River watershed. Ten sites were randomly …

Conspecific Attraction In A Low-Density Population Of A Threatened Songbird, Daniel James Albrecht-Mallinger

Theses and Dissertations

Many organisms use both vegetation structure and social cues in selecting habitats. Many species of songbirds use the presence of breeding conspecifics as a social cue and sign of habitat quality, and can be induced to settle in unoccupied habitats by artificially broadcasting breeding song, a process referred to as “conspecific attraction”. In our study, we tested response to conspecific attraction a low-density population of the threatened Golden-winged Warbler (Vermivora chrysoptera) in Highland County, VA. Response to broadcast song was observed, with a modest increase in mean male abundance at survey points within 250 meters of treatments, and mean abundance …

Indirect Effects Between Deer, Mice, And The Gypsy Moth In A Forest Community, John Wojcikiewicz

Theses and Dissertations

White-tailed deer are ecosystem engineers that dramatically alter forest understory vegetation. Consequently, deer can impact many species in a forest through both direct and indirect effects. One species that deer may indirectly affect is the gypsy moth, whose pupae are preyed upon by the white-footed mouse. Through alterations to understory habitat of mice, deer may reduce mouse predation on gypsy moth pupae. In this study, I tested for indirect effects of deer on the gypsy moth by comparing mouse abundance, vegetation properties, and predation on pupae inside, and outside, of long-term deer exclosures. Overall, I did not find evidence for …

Forest Net Primary Production Resistance Across A Gradient Of Moderate Disturbance, Ellen Goodrich-Stuart

Theses and Dissertations

The global carbon (C) balance is vulnerable to disturbances that alter terrestrial C uptake and loss. Moderate disturbances that kill or defoliate only a subset of canopy trees such as insect defoliation, drought, and age-related senescence are increasing in extent and frequency; yet, little is known about the effect of moderate disturbance on forest production and the mechanisms sustaining or supporting the recovery of the C cycle across a range of moderate disturbance severities. We used a broad plot-scale gradient of upper canopy tree mortality within a large manipulation of forest disturbance to: 1) quantify how aboveground wood net primary …

Causes And Consequences Of Algal Blooms In The Tidal Fresh James River, Joseph Wood

Theses and Dissertations

This dissertation includes 3 chapters which focus on algal bloom of the tidal fresh James River. The first chapter describes nutrient and light limitation assays performed on algal cultures and draw conclusions about long-term patterns in nutrient limitation by comparing results with a previous study . This chapter also describes the influence of riverine discharge upon nutrient limitation in a point-source dominated estuary. This chapter was published in Estuaries and Coasts (Wood and Bukaveckas 2014). The second chapter presents the first comprehensive assessment of the occurrence of the cyanotoxin Microcystin in water and biota of the James River. Data presented …

The Occurrence And Consequences Of Conspecific Brood Parasitism In The Prothonotary Warbler (Protonotaria Citrea), Anna Tucker

Theses and Dissertations

Brood parasites avoid costs associated with raising young by adding eggs to another individual’s clutch and providing no parental care. When conspecific brood parasitism occurs in species with high parental investment, we expect hosts to suffer costs for raising an enlarged brood. Here I describe conspecific brood parasitism (CBP) in the prothonotary warbler using maternal exclusion analyses of 333 family groups. I found that 23.4% of clutches contained at least one offspring that was not matched to the social mother and determined that parasitism seems to be an opportunistic tactic. Hosts had lower average annual reproductive success than non-hosts, but …

Hcpr Of Porphyromonas Gingivalis Utilizes Heme To Bind No, Benjamin Belvin

Theses and Dissertations

The obligate anaerobe Porphyromonas gingivalis is the etiological agent responsible for periodontal disease. It must withstand high levels of reactive nitrogen species in the oral cavity generated by the host and other oral flora. The mechanisms allowing for protection against such stress remain poorly understand. HcpR is an FNR-CRP family regulator that has been implicated in regulation of the nitrosative stress response. In this study we characterize the biochemical properties of HcpR. It is a homo-dimer that is composed of 3 domains – a heme-binding domain, dimerization helix, and a DNA-binding domain. Our studies show that HcpR binds the heme …

Forest Edges Enhance Mate-Finding In The European Gypsy Moth, Lymantria Dispar, Lily Thompson

Theses and Dissertations

Understanding movement capabilities of individuals within a landscape is essential to identifying the effects of habitat boundaries on species abundances, ranges, and spread rates. Movement barriers due to habitat fragmentation may reduce mate-finding ability in some species, particularly in heterogeneous landscapes containing low-density populations. This study focuses on the effects of habitat type and edge on mate-finding in an invasive defoliator, the European gypsy moth. Adult European gypsy moth males locate mates by following pheromones released by flightless females. Reduced mate-finding was expected in fields and near forest edges based on geographic variation in invasion rates and pheromone plume dynamics. …

Increased Circulatory Lipopolysaccharide From A High Fat Diet Aggravates Inflammation And Exacerbates Renal Failure, Samuel Righi

Theses and Dissertations

Kidney failure is frequently associated with the risk factors linked to metabolic syndrome. Lipopolysaccharide (LPS) is a potent inflammatory molecule, which has increased absorption from the gut into blood circulation following a high fat and high-energy diet. We hypothesized that LPS from a high fat diet can amplify inflammation, thereby exacerbating chronic kidney disease and associated disorders. We have found that adding a high fat diet to renal insufficient mice significantly progressed their kidney disease as well as associated disorders, compared to both a high fat diet and renal insufficiency alone. Additionally, we were able to demonstrate in vitro that …

Ampk Activators Regulate Contractile Function Of Mesenteric Arteries, Victoria Locke

Theses and Dissertations

Vasoconstrictor tone in the splanchnic circulation redistributes blood flow during hemorrhage and resuscitation. A metabolic sensor, 5’adenosine monophosphate-activated protein kinase (AMPK), has been proposed to relax arteries by inhibiting myosin light chain (MLC) kinase (MLCK) and rho kinase (ROCK) activities. Because AMPK activation might be beneficial in re-establishing splanchnic blood flow during resuscitation, we sought to explore the relative ability of AMPK activators (AICAR, A769662, berberine (BBR) and simvastatin (SIMV)) to relax mesenteric artery (MA) contraction. Our data revealed that these drugs caused vasorelaxation when tissues were stimulated either with KCl (producing primarily a Ca2+ dependent contraction) or phenylephrine (PE; …

Hydroxocobalamin Treatment For Carbon Monoxide Exposures: Characterizing Hemoglobin Changes And Testing For Neurological Sequelae, Leonardo Somera

Theses and Dissertations

Prior work in our lab has indicated that reduced Hydroxocobalamin (B12r) can be added to human blood and is able to convert carbon monoxide (CO) into carbon dioxide. This has great potential as a direct antidote to mitigate the toxic effects of CO poisoning which is a public health risk. In the first part of our work, we use highly specific wavelengths of light and Raman spectroscopy to study changes in Carboxyhemoglobin (COHb) between blood treated with oxygen and blood treated with oxygen and B12r in a flowing circuit of blood. Using Raman spectroscopy, we found that the addition of …

The Effect Of Retinoic Acid On Rai1 And Identification Of Retinoic Acid Receptor Binding Site In Human Rai1, Bingjie Xue

Theses and Dissertations

Previous studies showed haploinsufficiency of RAI1 is the main cause of Smith-Magenis syndrome (SMS). SMS is a developmental neurobehavioral syndrome characterized by intellectual disability, congenital anomalies, obesity, neurobehavioral abnormalities, and disrupted circadian sleep-wake pattern. SMS is caused by deletion or mutation of chromosomal region 17p11.2 that includes RAI1. Studies in the Elsea lab have shown that RAI1 is a dosage-sensitive gene. Haploinsufficiency of RAI1 leads to dysregulation of CLOCK, NR1D2, POMC, and BDNF, which are responsible for circadian rhythm, metabolism, and cognitive development. Based on the data from Elsea’s recent study on zebrafish, rai1 gene expression in zebrafish is regulated …

A Nuclear Dna Perspective On Delineating Evolutionarily Significant Lineages In Polyploids: The Case Of The Endangered Shortnose Sturgeon (Acipenser Brevirostrum), Tim L. King, Anne P. Henderson, Boyd E. Kynard, Micah C. Kieffer, Douglas L. Peterson, Aaron W. Aunins, Bonnie L. Brown

Biology Publications

The shortnose sturgeon, Acipenser brevirostrum, oft considered a phylogenetic relic, is listed as an “endangered species threatened with extinction” in the US and “Vulnerable” on the IUCN Red List. Effective conservation of A. brevirostrum depends on understanding its diversity and evolutionary processes, yet challenges associated with the polyploid nature of its nuclear genome have heretofore limited population genetic analysis to maternally inherited haploid characters. We developed a suite of polysomic microsatellite DNA markers and characterized a sample of 561 shortnose sturgeon collected from major extant populations along the North American Atlantic coast. The 181 alleles observed at 11 loci …

Barrier Island Morphology And Sediment Characteristics Affect The Recovery Of Dune Building Grasses Following Storm-Induced Overwash, Steven T. Brantley, Spencer Bissett, Donald R. Young, Catherine W. V. Wolner, Laura J. Moore

Biology Publications

Barrier islands are complex and dynamic systems that provide critical ecosystem services to coastal populations. Stability of these systems is threatened by rising sea level and the potential for coastal storms to increase in frequency and intensity. Recovery of dune-building grasses following storms is an important process that promotes topographic heterogeneity and long-term stability of barrier islands, yet factors that drive dune recovery are poorly understood. We examined vegetation recovery in overwash zones on two geomorphically distinct (undisturbed vs. frequently overwashed) barrier islands on the Virginia coast, USA. We hypothesized that vegetation recovery in overwash zones would be driven primarily …

On The Challenges Of Modeling The Net Radiative Forcing Of Wetlands: Reconsidering Mitsch Et Al. 2013, Scott C. Neubauer

Biology Publications

Wetlands play a role in regulating global climate by removing carbon dioxide (CO2) from the atmosphere and sequestering it as soil carbon, and by emitting methane (CH4) and nitrous oxide (N2O) to the atmosphere. In a recent article in this journal (Mitsch et al. Landscape Ecol 28:583–597, 2013), CO2 sequestration and CH4 emissions were modeled for several freshwater wetlands that vary in vegetation type, climate, and hydrology. The authors of that study made significant errors that caused them to underestimate the importance of wetland CH4 emissions on climate dynamics. Here, I reanalyze the Mitsch et al. dataset and show that …

Morphine Enhances Hiv-1sf162-Mediated Neuron Death And Delays Recovery Of Injured Neurites, Ruturaj R. Masvekar, Nazira El-Hage, Kurt F. Hauser, Pamela E. Knapp

Anatomy and Neurobiology Publications

HIV-1 enters the CNS soon after initial systemic infection; within the CNS parenchyma infected and/or activated perivascular macrophages, microglia and astrocytes release viral and cellular toxins that drive secondary toxicity in neurons and other cell types. Our previous work has largely modeled HIV-neuropathology using the individual viral proteins Tat or gp120, with murine striatal neurons as targets. To model disease processes more closely, the current study uses supernatant from HIV-1-infected cells. Supernatant from HIV-1SF162-infected differentiated-U937 cells (HIV+sup) was collected and p24 level was measured by ELISA to assess the infection. Injection drug abuse is a significant risk factor for HIV-infection, …

Post-Acute Brain Injury Urinary Signature: A New Resource For Molecular Diagnostics, Andrew K. Ottens, Jillian E. Stafflinger, Hailey E. Griffin, Richard D. Kunz, David X. Cifu, Janet P. Niemeier

Anatomy and Neurobiology Publications

Heterogeneity within brain injury presents a challenge to the development of informative molecular diagnostics. Recent studies show progress particularly in cerebrospinal fluid with biomarker assays targeting one or a few structural proteins. Protein-based assays in peripheral fluids, however, have been more challenging to develop in part due to restricted and intermittent barrier access. Further, a greater number of molecular variables may be required to inform on patient status given the multifactorial nature of brain injury. Presented is an alternative approach profiling peripheral fluid for a class of small metabolic by-products rendered by ongoing brain pathobiology. Urine specimens were collected for …

Bioinformatics And Biomedical Informatics, Kayvan Najarian, Rachid Deriche, Mark A. Kon, Nina S. T. Hirata

Computer Science Publications

No abstract provided.

In Vitro Propagation Of Gentiana Scabra Bunge – An Important Medicinal Plant In The Chinese System Of Medicines, Shih-Hung Huang, Dinesh Chandra Agrawal, Fang-Sheng Wu, Hsin-Sheng Tsay

Biology Publications

Background: Gentiana scabra Bunge commonly known as `Long dan cao' in China has been used in traditional Chinese medicines for more than 2000 years. Dry roots and rhizome of the herb have been used for the treatment of inflammation, anorexia, indigestion and gastric infections. Iridoids and secoiridoids are the main bioactive compounds which attribute to the pharmacological properties of this plant. The species is difficult to mass propagate by seed due to the low percentage of germination and limited dormancy period. Wild populations in some locations are considered to be in the endangered category due to over exploitation.

Results: In …

Reduction Of The Pectoral Spine And Girdle In Domesticated Channel Catfish Is Likely Caused By Changes In Selection Pressure, Michael L. Fine

Biology Publications

Locked pectoral spines of the Channel Catfish Ictalurus punctatus more than double the fish's width and complicate ingestion by gape-limited predators. The spine mates with the pectoral girdle, a robust structure that anchors the spine. This study demonstrates that both spine and girdle exhibit negative allometric growth and that pectoral spines and girdles are lighter in domesticated than in wild Channel Catfish. This finding could be explained by changes in selection pressure for spine growth during domestication or by an epigenetic effect in which exposure to predators in wild fish stimulates pectoral growth. We tested the epigenetic hypothesis by exposing …

Spatiotemporal Variability And Sound Characterization In Silver Croaker Plagioscion Squamosissimus (Sciaenidae) In The Central Amazon, Alfredo Borie, Hin-Kiu Mok, Ning L. Chao, Michael L. Fine

Biology Publications

Background

The fish family Sciaenidae has numerous species that produce sounds with superfast muscles that vibrate the swimbladder. These muscles form post embryonically and undergo seasonal hypertrophy-atrophy cycles. The family has been the focus of numerous passive acoustic studies to localize spatial and temporal occurrence of spawning aggregations. Fishes produce disturbance calls when hand-held, and males form aggregations in late afternoon and produce advertisement calls to attract females for mating. Previous studies on five continents have been confined to temperate species. Here we examine the calls of the silver croakerPlagioscion squamosissimus, a freshwater equatorial species, which experiences constant …

Regional And Scale-Specific Effects Of Land Use On Amphibian Diversity [Poster], James R. Vonesh, David Marsh, J. J. Apodaca, Karen H. Beard, Jane M. Bell, Christine Bozarth, Derrick Carper, Julie Charbonnier, Bradley J. Cosentino, Andreia Dantas, Elizabeth A. Forys, Miranda Foster, Jaquelyn General, Kristen S. Genet, Macie Hanneken, Kyle Hess, Shane Hill, Faisal Iqbal, Kara Jones, Nancy E. Karraker, Eran Kilpatrick, Tom A. Langen, James Langford, Katherine Lauer, Alison J. Mccarthy, Joseph Neale, Saumya Patel, Austin Patton, Cherie Southwick, Nathaniel Stearrett, Nick Steijn, Mohammad Tasleem, Joseph Taylor

Biology Presentations

Background/Question/Methods

Habitat loss and degradation influence amphibian distributions and are important drivers of population declines. Our previous research demonstrated that road disturbance, development and wetland area consistently influence amphibian richness across regions of the U.S. Here, we examined the relative importance of these factors in different regions and at multiple spatial scales. Understanding the scales at which habitat disturbance may be affecting amphibian distributions is important for conservation planning. Specifically, we asked: 1) Over what spatial scales do distinct landscape features affect amphibian richness? and 2) Do road types (non-rural and rural) have similar effects on amphibian richness? This is …

A Metagenomic Assessment Of The Bacteria Associated With Lucilia Sericata And Lucilia Cuprina (Diptera: Calliphoridae), Baneshwar Singh, Tawni L. Crippen, Longyu Zheng, Andrew T. Fields, Ziniu Yu, Qun Ma, Thomas K. Wood, Scot E. Dowd, Micah Flores, Jeffery K. Tomberlin, Aaron M. Tarone

Forensic Science Publications

Lucilia Robineau-Desvoidy (Diptera: Calliphoridae) is a blow fly genus of forensic, medical, veterinary, and agricultural importance. This genus is also famous because of its beneficial uses in maggot debridement therapy (MDT). Although the genus is of considerable economic importance, our knowledge about microbes associated with these flies and how these bacteria are horizontally and trans-generationally transmitted is limited. In this study, we characterized bacteria associated with different life stages of Lucilia sericata (Meigen) and Lucilia cuprina(Wiedemann) and in the salivary gland of L. sericata by using 16S rDNA 454 pyrosequencing. Bacteria associated with the salivary gland of …

Neuropathological Responses To Chronic Nmda In Rats Are Worsened By Dietary N-3 Pufa Deprivation But Are Not Ameliorated By Fish Oil Supplementation, Vasken L. Keleshian, Matthew Kellom, Hyung-Wook Kim, Ameer Y. Taha, Yewon Cheon, Miki Igarashi, Stanley I. Rapoport, Jagadeesh S. Rao

Anatomy and Neurobiology Publications

Background

Dietary long-chain n-3 polyunsaturated fatty acid (PUFA) supplementation may be beneficial for chronic brain illnesses, but the issue is not agreed on. We examined effects of dietary n-3 PUFA deprivation or supplementation, compared with an n-3 PUFA adequate diet (containing alpha-linolenic acid [18:3 n-3] but not docosahexaenoic acid [DHA, 22:6n-3]), on brain markers of lipid metabolism and excitotoxicity, in rats treated chronically with NMDA or saline.

Methods

Male rats after weaning were maintained on one of three diets for 15 weeks. After 12 weeks, each diet group was injected i.p. daily with saline (1 ml/kg) or a subconvulsive dose …

Hybrid Energy Harvesting, Nazanin R. Ghavamabadi

Graduate Research Posters

Between 20% to 50% of industrial energy input is lost as waste heat in the form of hot exhaust gases, cooling water and energy loss from generating equipment. Vibrations and variable heating are a common form of waste energy in motors, generators, power cables exposed to ambient temperatures, fuel exhausts from vehicles, and various types of heavy machinery. The recovery of even a fraction of this lost energy would have a transformational impact on the utility industry since the demand for energy is increasing and the impact of this demand on the environment is significant. Recent technical breakthroughs in new …