Digital Commons Network^™

Zooplankton Abundance, Community Composition And Grazing In The James River Estuary (Virginia, Usa), Laura E. Barry

Theses and Dissertations

This study examined the extent to which zooplankton in the James River Estuary (Virginia, USA) exploit the available algal-food resources. Zooplankton abundance, community composition and grazing rates were assessed at three locations which included a site with high algal production (near the VCU Rice Center) and two sites where algal production was lower. Grazing rates were measured by determining the rate of phytoplankton decline (as chlorophyll a) during 48-hour incubation experiments in the presence and absence of zooplankton. Significant differences in zooplankton abundance were observed among the three sites, with the greatest average zooplankton density (434 ± 69 ind/L) occurring …

Examining The Effects Of Penning On Juvenile Eastern Box Turtles (Terrapene Carolina Carolina), Nicolas Frederick

Theses and Dissertations

Box turtle (Terrapene carolina) populations have been declining over the last several decades, and one major cause is increasing urbanization. As a result of habitat fragmentation, wildlife managers are frequently turning to new and alternative management strategies. Traditional box turtle management has included relocation, which has been met with limited success. This study aims to combine these strategies with another less-studied one: forcing turtles to overwinter on site by penning them in an outdoor enclosure. Two sets of juvenile box turtles were released at the Virginia Commonwealth University Rice Center: one penned on site in a pen for one year, …

Distribution And Diversity Of Archaeal And Bacterial Ammonia Oxidizers In Salt Marsh Sediments, Nicole S. Moin, Katelyn A. Nelson, Alexander Bush, Anne E. Bernhard

Biology Faculty Publications

Diversity and abundance of ammonia-oxidizing Betaproteobacteria (β-AOB) and archaea (AOA) were investigated in a New England salt marsh at sites dominated by short or tall Spartina alterniflora (SAS and SAT sites, respectively) or Spartina patens (SP site). AOA amoA gene richness was higher than β-AOB amoA richness at SAT and SP, but AOA and β-AOB richness were similar at SAS. β-AOB amoA clone libraries were composed exclusively of Nitrosospira-like amoA genes. AOA amoA genes at SAT and SP were equally distributed between the water column/sediment and soil/sediment clades, while AOA amoA sequences at SAS were primarily affiliated with the …

Phylogeography And Postglacial Dispersal Of Smallmouth Bass (Micropterus Dolomieu) Into The Great Lakes, W. Calvin Borden, Robert A. Krebs

Biological, Geological, and Environmental Faculty Publications

Refugia and dispersal routes of smallmouth bass (Micropterus dolomieu) into the Great Lakes were identified using 427 mitochondrial sequences from across their native range. Overall, smallmouth bass accessed the Great Lakes via long-distance dispersal from multiple refugia, and the distribution of genetic variation reflected the consequences of vicariant, dispersal, and paleogeological events. Proximity of lakes to glacial outlets had a greater predictive power on the resulting distribution of mitochondrial diversity relative to interbasin migration. Populations in the Eastern and Interior Highlands contained the most divergent and oldest haplotypes, reflecting their role as glacial refugia and subsequent high incidence of endemicity. …

Remodeling Of The Tight Junction During Recovery From Exposure To Hydrogen Peroxide In Kidney Epithelial Cells, Jeannette E. Gonzalez, R. J. Digeronimo, D'Ann E. Arthur, Jonathan M. King

Biology Faculty Research

Renal ischemia-reperfusion injury results in oxidative stress-induced alterations in barrier function. Activation of the mitogen-activated protein (MAP) kinase pathway during recovery from oxidative stress may be an effector of oxidant-induced tight junction reorganization. We hypothesized that tight junction composition and barrier function would be perturbed during recovery from oxidative stress. We developed a model of short-term H₂O₂ exposure followed by recovery using Madin Darby canine kidney (MDCK II) cells. H₂O₂ perturbs barrier function without a significant cytotoxic effect except in significant doses. ERK-1/2 and p38, both enzymes of the MAP kinase pathway, were activated …

Remote Sensing Of Harmful Algal Blooms In The Mississippi Sound And Mobile Bay: Modelling And Algorithm Formation, Dan Martin Holiday

Dissertations

The incidence and severity of harmful algal blooms have increased in recent decades, as have the economic effects of their occurrence./The diatom Pseudo-nitzschia spp. caused fisheries closures in Mobile Bay during 2005 due to elevated levels of domoic acid. In the previous 4 years Karenia brevis counts of >5,000 cells L"1 have occurred in Mobile Bay and the Mississippi Sound. Population levels of this magnitude had previously been recorded only in 1996. Increases in human populations, urban sprawl, development of shoreline properties, sewage effluent and resultant changes in NP ratios of discharge waters, and decline in forest and marsh lands, …

First Record Of The Extinct Sawfish Propristis Schweinfurthi Dames, 1883 (Batoidea: Pristiformes: Pristidae) From The Middle Eocene Of Spain, Francesc Farrés, Harry L. Fierstine

Biological Sciences

A partial rostrum of Propristis schweinfurthi Dames, 1883 was collected in the Bartonian strata of northeastern Spain. The specimen represents the second record of the species from Europe, and the second occurrence of a sawfish (Mesopristis osonensis Farrés, 2003) from the Vic-Manlleu Marls Formation. In spite of some evidence to the contrary, Propristis probably preferred ecological conditions similar to extant sawfishes, i.e., inhabiting near shore tropical to subtropical seas with occasional excursions into freshwater.

The Effects Of A Reservoir On Genetic Isolation In Two Species Of Darters, Kerstin Lindsay Edberg

Masters Theses & Specialist Projects

The addition of dams into a riverine system causes a wide range of changes (i.e., sedimentation, erosion, thermal) to the river as well as to the fish assemblages of that river. Although there have been many studies documenting the changes that occur to the fish assemblages in the impounded river, there have been fewer studies examining the effects of a reservoir on the fish inhabiting the tributaries upstream of the impoundment. One possible impact of a reservoir could be to act as a barrier to fish migration between streams.
To determine if reservoirs restrict migration, the genetic diversity of two …

A New North American Genus Of Hetaeraiinae (Coleoptera: Histeridae), With Descriptions Of Six New Species From The U.S.A. And Mexico, Michael S. Caterino, Alexey K. Tishechkin

Publications

Renclasea n. gen., a genus of the Hetaeriinae (Histeridae), with six species, R. skelleyi n. sp. (United States: Florida and Georgia), R. falli n. sp. (United States: California), R. helavai n. sp. (United States: Arizona), R. mexicana n. sp. (Mexico: Hidalgo), R. occidentalis n. sp. (United States: Arizona and New Mexico) and R. cazieri n. sp. (United States: Arizona), are described, illustrated and diagnosed. The status of two female specimens of Renclasea from western Texas, apparently closely related to R. occidentalis, remains uncertain. The only host record available for the genus is an association of R. mexicana with undetermined species …

Introducing Mothur: Open-Source, Platform-Independent, Community-Supported Software For Describing And Comparing Microbial Communities, Courtney Robinson

Department of Biology Faculty Publications

mothur aims to be a comprehensive software package that allows users to use a single piece of software to analyze community sequence data. It builds upon previous tools to provide a flexible and powerful software package for analyzing sequencing data. As a case study, we used mothur to trim, screen, and align sequences; calculate distances; assign sequences to operational taxonomic units; and describe the α and β diversity of eight marine samples previously characterized by pyrosequencing of 16S rRNA gene fragments. This analysis of more than 222,000 sequences was completed in less than 2 h with a laptop computer.

The Behavioral And Pharmacological Actions Of Nmda Receptor Antagonism Are Conserved In Zebrafish Larvae, John Chen, Roshni Patel, Theodore Friedman, Kevin Jones

Department of Biology Faculty Publications

Dizocilpine maleate (MK-801) is one of several NMDA receptor antagonists that is widely used to pharmacologically model the symptoms of psychosis and schizophrenia in animals. MK-801 elicits behaviors in adult zebrafish (Danio rerio) that are phenotypically consistent with behaviors observed in humans and rodents exposed to tbhe drug. However, the molecular and cellular processes that mediate the psychotomimetic, cognitive and locomotive behaviors of MK-801 are unclear. We exposed zebrafish larvae to MK-801 to assess their merit as a model organism to elucidate the behavioral effects of NMDA receptor blockade. Zebrafish larvae were acutely immersed in MK-801 to assess the effect …

Applications Of Natural Products In The Control Of Mosquito-Transmitted Diseases, Jesse Hardin, Fatimah Linda Collier Jackson

Department of Biology Faculty Publications

Mosquito-transmitted diseases remain one of the most significant causes of mortality in the African continent, despite successes in controlling these diseases in other regions of the world. The disproportionate impact in areas of poverty suggests a need for control that is efficient and does not require complex technological control strategies. Focusing on the vectors of disease, the mosquito, there are many alternatives to synthetic, chemical pesticides that await discovery and development. Although some natural products have been described, there is still a need for continuing research that incorporates endogenous knowledge in the selection process for potential vector control candidates. Recent …

Dissolved Organic Matter Influences The Timing Of Embryonic Development Of The Purple Sea Urchin, Strongylocentrotus Purpuratus., Corbin J. Hodges

Master's Theses

Marine dissolved organic matter (DOM) comprises one of the largest carbon reservoirs on earth and has long been considered a potential energy source for marine invertebrates. The importance of DOM transport has been adequately demonstrated for unicellular organisms, where DOM can meet 100% of an organisms energy needs, but the effects of DOM uptake for marine metazoans are less well understood. In this study, three general areas involving the influence of DOM transport to marine invertebrates were explored. First, we assessed the effects of using seawater exposed to high intensity ultraviolet radiation (UVR) on the study organism; embryos of the …

Pulsatile Flow Of Blood In A Constricted Artery With Body Acceleration, Devajyoti Biswas, Uday Shankar Chakraborty

Applications and Applied Mathematics: An International Journal (AAM)

Pulsatile flow of blood through a uniform artery in the presence of a mild stenosis has been investigated in this paper. Blood has been represented by a Newtonian fluid. This model has been used to study the influence of body acceleration and a velocity slip at wall, in blood flow through stenosed arteries. By employing a perturbation analysis, analytic expressions for the velocity profile, flow rate, wall shear stress and effective viscosity, are derived. The variations of flow variables with different parameters are shown diagrammatically and discussed. It is noticed that velocity and flow rate increase but effective viscosity decreases, …

Remarks On The Stability Of Some Size-Structured Population Models Vi: The Case When The Death Rate Depends On Juveniles Only And The Growth Rate Depends On Size Only And The Case When Both Rates Depend On Size Only, M. El-Doma

Applications and Applied Mathematics: An International Journal (AAM)

We continue our study of size-structured population dynamics models when the population is divided into adults and juveniles, started in El-Doma (to appear 1) and continued in El-Doma (to appear 2). We concentrate our efforts in two special cases, the first is when the death rate depends on juveniles only and the growth rate depends on size only, and, the second is when both the death rate and the growth rate depend on size only. In both special cases we assume that the maximum size for an individual in the population is infinite. We identify three demographic parameters and show …

The Ecology Of The Peaks Of Otter Salamander (Plethodon Hubrichti) In Sympatry With The Eastern Red-Backed Salamander (Plethodon Cinereus), Norman Reichenbach, Andrew Kniowski

Faculty Publications and Presentations

The Peaks of Otter Salamander, Plethodon hubrichti, is found along a 19 km length of the Blue Ridge Mountains, Virginia, USA, often in sympatry with the Eastern Red-backed Salamander, P. cinereus. In a sympatric area of Bedford County, Virginia, we conducted a mark-recapture study on a 10 × 10 m site. Surface densities of salamanders increased as the number of days without precipitation prior to a collection event increased. This suggests vertical movements in response to surface moisture. When salamanders returned to the surface after rain, individuals appeared to “shuffle” between rocks and likely, leaf litter. That is, we were …

Gold Nanoparticle Interactions And Impact Upon A Common Biofilm Source: Legionella Pneumophila , Amber Stojak

All Theses

There exists widespread concern of pathogenic bacteria colonizing and establishing biofilms in water systems providing a direct exposure route to the public. Legionella are widely distributed in human-made and natural environments, and colonization lends the potential to infect human hosts that may lead to the development of Legionnaire's Disease. Silver has been used in cooling towers and water filtration systems for removal of planktonic bacteria and biofilms; however permanent removal of L. pneumophila biofilms with metal ions is impossible when established biofilms are in hard to access places such as dead end piping or inside a protozoan host. Bulk metals …

Using A Multimedia Assessment Tool To Impact Evolution Education Strategies In South Carolina's Public High Schools, Matthew Johnson

All Theses

The theory of evolution is widely accepted as one of the fundamental disciplines of modern science. Evolution provides a foundation for all aspects of biology, and thus it is essential that present and future biologists have a detailed understanding of evolutionary principles. However, since the famous Scopes trial in 1925, the teaching of evolutionary theory in the public school system has been under attack. Though several court cases over the last 85 years have continually supported evolution and discredited creationism (the idea that evolution cannot explain the diversity of life on earth and therefore must have arisen through the influence …

Don't Diss Integration: A Comment On Ricklefs's Disintegrating Communities, Rob W. Booker, Ragan M. Callaway, Lohengrin A. Cavieres, Zaal Kikvidze, Christopher J. Lortie, Richard Michalet, Francisco I. Pugnaire, Alfonso Valiente-Banuet, Thomas G. Whitham

Biological Sciences Faculty Publications

No abstract provided.

Drosophila Adult Eye Model To Teach Scanning Electron Microscopy In An Undergraduate Cell Biology Laboratory, Meghana Tare, Oorvashi Roy Puli, Sarah M. Oros, Amit Singh

Biology Faculty Publications

We have devised an undergraduate laboratory exercise to study tissue morphology using fruit fly, Drosophila melanogaster, as the model organism. Drosophila can be reared in a cost effective manner in a short period of time. This experiment was a part of the undergraduate curriculum of the cell biology laboratory course aimed to demonstrate the use of scanning electron microscopy (SEM) technique to study the morphology of adult eye of Drosophila. The adult eye of Drosophila is a compound eye, which comprises of 800 unit eyes, and serves as an excellent model for SEM studies. We used flies that …

Remarks On The Stability Of Some Size-Structured Population Models V: The Case When The Death Rate Depends On Adults Only And The Growth Rate Depends On Size Only, M. El-Doma

Applications and Applied Mathematics: An International Journal (AAM)

We continue our study of size-structured population dynamics models when the population is divided into adults and juveniles, started in El-Doma (To appear). We concentrate our efforts in the special case when the death rate depends on adults only, the growth rate depends on size only and the maximum size for an individual in the population is infinite. Three demographic parameters are identified and are shown to determine conditions for the (in)stability of a nontrivial steady state. We also give examples that illustrate the stability results. The results in this paper generalize previous results, for example, see Calsina, et al. …

Remarks On The Stability Of Some Size-Structured Population Models Iv: The General Case Of Juveniles And Adults, M. El-Doma

Applications and Applied Mathematics: An International Journal (AAM)

The stability of some size-structured population dynamics models is investigated when the population is divided into adults and juveniles. We determine the steady states and study their stability. We also give examples that illustrate the stability results. The results in this paper generalize previous results, for example, see Calsina, et al. (2003), El-Doma (2006), Farkas, et al. (2008), and El-Doma (2008 a).

Two-Layered Model Of Blood Flow Through Composite Stenosed Artery, Padma Joshi, Ashutosh Pathak, B. K. Joshi

Applications and Applied Mathematics: An International Journal (AAM)

In this paper a steady, axisymmetric flow, with a constricted tube has been studied. The artery has been represented by a two-layered model consisting of a core layer and a peripheral layer. It has been shown that the resistance to flow and wall shear stress increases as the peripheral layer viscosity increases. The results are compared graphically with those of previous investigators. It has been observed that the existence of peripheral layer is useful in representation of diseased arterial system.

Protein Secondary Structure Prediction Using Parallelized Rule Induction From Coverings, Leong Lee, Cyriac Kandoth, Jennifer Leopold, Ronald L. Frank

Computer Science Faculty Research & Creative Works

Protein 3D structure prediction has always been an important research area in bioinformatics. In particular, the prediction of secondary structure has been a well-studied research topic. Despite the recent breakthrough of combining multiple sequence alignment information and artificial intelligence algorithms to predict protein secondary structure, the Q3 accuracy of various computational prediction algorithms rarely has exceeded 75%. In a previous paper [1], this research team presented a rule-based method called RT-RICO (Relaxed Threshold Rule Induction from Coverings) to predict protein secondary structure. The average Q3 accuracy on the sample datasets using RT-RICO was 80.3%, an improvement over comparable computational methods. …

Population Ecology And Reproductive Biology Of The Diamondback Watersnake, Nerodia Rhombifer (Serpentes: Colubridae), In Southernmost Texas, Ruben D. Zamora

Theses and Dissertations - UTB/UTPA

Nerodia rhombifer is a polytypic, semi-aquatic snake with a broad geographical distribution ranging from the American Midwest southward to Chiapas, Mexico. Although relatively abundant throughout much of its range, few ecological studies of the species have been conducted. This study provides basic population ecology information in a subtropical habitat. Population data were obtained in a mark-recapture study at Santa Ana National Wildlife Refuge, Hidalgo County, Texas, from August 1995 to December 1998. Specimens taken elsewhere in Hidalgo County provided information on the reproductive biology. This study provides the first absolute density estimates from anywhere within the species’ range. Quantitative information …

Isoform- And Cell-Specific Function Of Tyrosine Decarboxylase In The Drosophila Malpighian Tubule, Edward M. Blumenthal

Biological Sciences Faculty Research and Publications

The biogenic amine tyramine (TA) is a potent diuretic factor when applied to the Malpighian tubule (MT) of Drosophila melanogaster, stimulating both urine production and transepithelial chloride conductance. Isolated MTs can respond not only to TA but also to its precursor, tyrosine; this observation led to the proposal that MTs are able to synthesize TA from applied tyrosine through the action of the enzyme tyrosine decarboxylase (TDC). In the current study it is shown that the non-neuronal isoform of TDC, Tdc1, is expressed in the principal cells of the MT. A mutant allele of Tdc1, Tdc1^{f03311 …}

Conservation Genetics And Systematics Of Several Turtles Species In The Southeastern United States, Joshua Robert Ennen

Dissertations

Chelonians (i.e., turtles) are an imperiled group of reptiles with about 66% of the recognized species listed as threatened by the IUCN. Most chelonian species have a unique set of life history traits (i.e., longevity, delayed sexual maturity, and low juvenile survivorship), which makes their populations exceedingly sensitive to increases in adult and juvenile moralities. With numerous anthropogenic effects (e.g., habitat alteration, exploitation, and over harvesting) negatively influencing mortality rates, chelonians have experienced global precipitous declines and extinctions.

This dissertation focuses on species within two chelonian genera, Gopherus and Graptemys. Although these two genera are vastly different ecologically, they are …

Seasonality And Movement Of Adventive Populations Of The Arundo Wasp (Hymenoptera: Eurytomidae), A Biological Control Agent Of Giant Reed In The Lower Rio Grande Basin In South Texas, Alexis Racelis, Carol Goolsby, Patrick J. Moran

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The arundo wasp, Tetramesa romana Walker, has been permitted as a biological control agent for the invasive perennial grass, the giant reed, Arundo donax L. Evidence of adventive populations of the arundo wasp in the Lower Rio Grande Basin was confirmed with a spatio-temporal survey spanning more than 350 river miles. A total of 2,414 adult females of T. romana was collected during a 14month period of study in 2008–2009. This study documents the initial locations and regional expansion of two adventive populations of T. romana, centered around the cities of Eagle Pass and Laredo, TX. Peaks in T. …

The Role Of Spatial And Genetic Modeling To Biogeography, Dolly Lyne Crawford

Biology ETDs

One of the most persistent challenges in biology is explaining the distribution of animal taxa. Quantitative explanations for the distribution of organisms are challenged by the complexity of factors that potentially limit a species range, including topography, ecology, climate and biology. Because of limits on data and approaches, early biogeographers were hampered in their ability to explain patterns. Here, I benefit from two primary developments in biogeography. My research draws from the accumulation of data across several scientific disciplines and advances in spatial and statistical approaches to examine the distribution of animal taxa within an integrative biogeography framework. I combine …

The Physiological Ecology And Evolution Of Freezing Tolerance In Diploid Larrea Sp., Juliana Sibylla Medeiros

Biology ETDs

A basic understanding of vegetation responses to temperature and precipitation variability is paramount to the understanding of ecological adaptation, and comparisons across warm deserts are needed to increase our understanding of the controls on establishment in warm desert ecosystems. At the high latitude edges of warm deserts drought and freezing lower plant performance due to xylem dysfunction, as freeze-thaw embolism reduces stomatal conductance, or damage to leaf photosynthetic apparatus, as tissue desiccation reduces photosynthetic efficiency. Variation in these physiological responses can be observed across life-history stages, genetic background, climate gradients, and species, and this variation may be acted on by …