Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Bacteria (2)
- A277C (1)
- Africa (1)
- Agonistic interaction (1)
- Animal communication (1)
-
- Anti-predator adaptation (1)
- Anti-predator morphology (1)
- Araliaceae (1)
- Archaea (1)
- Asymmetric competition (1)
- Bacterial Community Structure (1)
- Bioacoustics (1)
- Bioassessment (1)
- Biogeography (1)
- Channel catfish (1)
- Community analysis (1)
- Cornus florida L. (1)
- Culex (1)
- Culex erraticus (1)
- Culex pipiens/restuans (1)
- Culex salinarius (1)
- Depth (1)
- Disturbance (1)
- Ecosystem Metabolism (1)
- Envrionmental Parameters (1)
- Erythrocyte-binding Ligands (1)
- Eutrophication (1)
- Extracelluar Enzyme Function (1)
- Fish (1)
- Haemoproteus (1)
Articles 1 - 15 of 15
Full-Text Articles in Biology
Distribution And Molecular Analysis Of Avian Malaria Vectors On Four Central Virginia Prothonotary Warbler (Protonotaria Citrea) Breeding Sites, Catherine Wallace
Distribution And Molecular Analysis Of Avian Malaria Vectors On Four Central Virginia Prothonotary Warbler (Protonotaria Citrea) Breeding Sites, Catherine Wallace
Theses and Dissertations
Avian malaria is a devastating disease that has decimated numerous bird species. This study sought to identify the vectors of avian malaria at four central Virginia Prothonotary warbler breeding sites. Twenty one thousand mosquitoes were collected and Culex salinarius, Cx. erraticus, and Cx. pipiens/restuans were found to be the dominant species at these sites. Geographic factors, such as crop land and forest type, were determined to be potential indicators for species abundance variation between sites. Of the mosquitoes collected, ninety one (0.4%) were identified as blood fed. The blood fed mosquitoes were found to have fed on avian, mammalian, amphibian, …
Depth And Time Related Variations Of Microbial Communiites In An Emergent Freshwater Wetland, Amy Jenkins
Depth And Time Related Variations Of Microbial Communiites In An Emergent Freshwater Wetland, Amy Jenkins
Theses and Dissertations
Soils, and the microbial communities contained within them, are vital for most chemical, physical, and biological processes. This study investigated how microbial community structure responded to environmental changes, such as hydrology, across vertical space (depth) and time in an emergent fresh water wetland. Research was conducted in a non-tidal freshwater wetland along the James River (Charles City County, Virginia) by establishing plots in two areas that experienced different hydrologic regimes and plant communities. Soil cores (30 cm) were collected monthly from January 2008 to February 2009, and then every two to three months thereafter until October 2009, for a total …
Canopy Disturbance And Reproduction In Cornus Florida L., Daniel Carr
Canopy Disturbance And Reproduction In Cornus Florida L., Daniel Carr
Theses and Dissertations
This study examined aspects of local reproductive variation in the flowering dogwood (Cornus florida L.) coincident with recent differences in primary canopy architecture. The dogwood trees in this study were impacted by a hurricane that created numerous treefall gaps, which created fine scale heterogeneity in the primary canopy. Fine scale disturbances in a forest can result in changes for multiple members of the forest community, including the reproductive responses of the trees and interspecific pollination mutualisms. Previously determined differences in offspring genetic structure suggested that pollen movement among genetically unstructured maternal individuals was significantly impacted between open, or disturbed, canopy …
Effect Of Ph On The Transcriptional Profile Of Porphyromonas Gingivalis W83, Nathan Maietta
Effect Of Ph On The Transcriptional Profile Of Porphyromonas Gingivalis W83, Nathan Maietta
Theses and Dissertations
Porphyromonas gingivalis, a gram-negative, anaerobic bacterium, is widely recognized as a causative agent for periodontal disease. Despite sequencing of the complete genome, no research exists examining gene regulation response in P. gingivalis to shifts in pH. Previous studies have shown that P. gingivalis is capable of surviving in the variety of micro- environmental niches found within the oral cavity, including basic and acidic pH conditions. However, the underlying mechanisms of this survival are not well understood. This study examined P. gingivalis by comparing bacteria shocked at three acidic to neutral pH conditions (5.5, 6.5 and 7.0) to bacteria vii shocked …
Variation In Sound Production Of The Blue Catfish, Ictalurus Furcatus., Zachary Ghahramani
Variation In Sound Production Of The Blue Catfish, Ictalurus Furcatus., Zachary Ghahramani
Theses and Dissertations
The blue catfish, Ictalurus furcatus, is an invasive species introduced to Virginia in 1974 and is the largest catfish in the United States. Like other Ictalurids, they are capable of producing disturbance calls via stridulation of the pectoral spine. These sounds can be made in air and water, and catfish can be preyed upon by both aerial and underwater predators. I characterized these putative distress calls by recording them in air and in the fish’s natural habitat. Sounds exhibited a wide variation in acoustic parameters relative to fish ontogeny: larger fish produced higher amplitude sounds with lower frequency bands. Sweep …
Evolutionary Relationships In Afro-Malagasy Schefflera (Araliaceae) Based On Nuclear And Plastid Markers, Morgan Gostel
Evolutionary Relationships In Afro-Malagasy Schefflera (Araliaceae) Based On Nuclear And Plastid Markers, Morgan Gostel
Theses and Dissertations
The genus Schefflera is the largest in Araliaceae, with approximately 900 species. Recent studies have shown that Schefflera is polyphyletic and represents no fewer than five distinct clades, each corresponding to a specific geographic region including Asia, continental Africa and Madagascar, Melanesia, the Neotropics, and a small clade distributed throughout several islands in the insular Pacific Ocean. The Afro-Malagasy clade contains nearly 50 species distributed throughout tropical, sub-Saharan Africa, Madagascar, the Comoros, and the Seychelles islands. Previous studies have suggested that this group is monophyletic, identifying two smaller subclades within Afro-Malagasy Schefflera corresponding roughly to informal groups identified as “Meiopanax” …
The Effects Of Hydrology And Vegetation On Microbial Community Structure And Soil Function In The Sediments Of Freshwater Wetlands, Christine Prasse
The Effects Of Hydrology And Vegetation On Microbial Community Structure And Soil Function In The Sediments Of Freshwater Wetlands, Christine Prasse
Theses and Dissertations
In wetland soils, hydrology is considered to be one of the primary factors shaping wetland function and microbial community structure, but plant-soil interactions are also important mechanisms affecting microbial nutrient transformations. The research presented here considered the interactive effect to describe how hydrology and the presence of plants alter the soil profile, the development of the bacterial community, and their associated functions. To achieve this goal, plots were established in three hydrologically-distinct regimes (Wet, Intermediate, and Dry) within a non-tidal freshwater wetland along the James River (Charles City County, Virginia). Inside each main plot, ten subplots were cleared of all …
Effects Of Alternative Prey As A Buffer To Predation Of Channel Catfish (Ictalurus Punctatus) By Largemouth Bass (Micropterus Salmoides), Shelley Nellis
Effects Of Alternative Prey As A Buffer To Predation Of Channel Catfish (Ictalurus Punctatus) By Largemouth Bass (Micropterus Salmoides), Shelley Nellis
Theses and Dissertations
Channel catfish have pectoral spines that lock to defend against gape-limited predators such as largemouth bass. Previous work indicated that spines increase survival of channel catfish exposed to bass but did not determine whether bass avoid catfish if less dangerous species are available. We presented bass with channel catfish and two alternatives, bluegill and goldfish, and compared order of ingestion, ingestion time, percent of successful strikes, and time spent chasing each prey species. We also presented the three species in a jar study that standardized position in the water column as well as in a net-pen study. The order of …
Factors Influencing The Abundance, Community Composition And Activity States Of Bacterioplankton From The Tidal Freshwater James River, Catherine Luria
Factors Influencing The Abundance, Community Composition And Activity States Of Bacterioplankton From The Tidal Freshwater James River, Catherine Luria
Theses and Dissertations
Aquatic bacteria respond to changing environmental conditions through a variety of mechanisms including changes in abundance, shifts in community composition and variable activity states. In the tidal-freshwater James River, variation in bacterial abundance was linked to nutrient availability and autochthonous production with highest bacterial densities associated with low-nutrient, high-chlorophyll a conditions. Laboratory experiments revealed that bacterial growth rates were nutrient limited at the low-nutrient site, while co-limitation (nutrients, glucose, light) was apparent at the high nutrient site. Despite large differences in abundance, community composition was similar based on TRFLP and 16S rDNA pyrosequencing. Community similarity was lower among rRNA libraries …
Long-Term Spatial And Temporal Variability Of Benthic Macroinvertebrate Communities: Implications For Bioassessment Of Lotic Systems, Eve O'Connor
Theses and Dissertations
The structure and composition of benthic macroinvertebrate communities can vary spatially and over time. Spatial and temporal variation along a stream has many implications for population and community dynamics, which may influence bioassessment programs. I examined variability in the benthic community of eight streams within the Polecat Creek, Virginia watershed. These streams vary in size from 1st to 4th order. The streams were sampled once every season for eleven years using standard bioassessment protocols. Macroinvertebrates were sampled from both sediment and submerged wood habitats at each site. The coefficient of variation (CV) was used to quantify among season, among year …
Mutation Of The Vesicular Monoamine Transporter-1 Gene Alters Its Protein Product, Abena Watson-Siriboe
Mutation Of The Vesicular Monoamine Transporter-1 Gene Alters Its Protein Product, Abena Watson-Siriboe
Theses and Dissertations
The vesicular monoamine transporter 1 (VMAT1) is essential for storage of monoamines, such as epinephrine and serotonin, in secretory vesicles of neuroendocrine cells. Recently the VMAT1 protein was detected in human and mouse brain, and mutations of the VMAT1 gene at single DNA nucleotides (single nucleotide polymorphisms or SNPs) were associated with schizophrenia. In this study, Chinese hamster ovarian cells were stably transfected with either human VMAT1 DNA (GenBank: #NM_003053.1 or DNA with the Thr4Pro SNP, which results in a threonine to proline change in amino acid number 4 of the VMAT1 protein. Western blot analysis revealed that cells with …
Spatial And Temporal Distribution Of Larval Fishes In A Large Tidal River., Harold Seelig
Spatial And Temporal Distribution Of Larval Fishes In A Large Tidal River., Harold Seelig
Theses and Dissertations
There are few published studies of larval fish assemblages from unregulated, tidal freshwater rivers. Patterns in the spatial and temporal distribution of larval fishes in the Mattaponi River were examined. Sampling took place on a weekly basis from February through August, 2006 and 2007. Larval fishes were categorized by taxa, reproductive guild, and residency guild. Group comparisons using multi-response permutation procedures (MRPP) indicated significant spatial and temporal differences in assemblage composition on multiple scales. Differences in assemblage composition were analyzed using non-metric multidimensional scaling (NMS). Interannual differences were attributable to anadromous and semi-migratory species. Seasonal differences were attributable to herrings, …
Expression & Purification Of Recombinant Plasmodium Falciparum Erythrocyte-Binding Ligands, Seward Joann Cofie
Expression & Purification Of Recombinant Plasmodium Falciparum Erythrocyte-Binding Ligands, Seward Joann Cofie
Theses and Dissertations
Plasmodium falciparum, the most virulent malarial parasite, is capable of invading all known human blood types. Erythrocyte invasion depends on specific parasite ligand and erythrocyte receptor interactions. These interactions are mediated by Region II of the P. falciparum erythrocyte binding ligands. Although invasion does not seem dependent upon a singular ligand, their individual contributions to the invasion process are yet to be explained. In this study, Region II of P. falciparum binding ligands BAEBL and JESEBL were transiently expressed as hexahistidyl recombinant proteins in COS-1 cells. Purification by column chromatography yielded 0.52 mg of BAEBL and 0.433 mg of JESEBL. …
Seasonal Patterns Of Nutrient Retention In A Restored Tidal Freshwater Stream Of The Mid-Atlantic Coastal Plain, Joseph Wood
Seasonal Patterns Of Nutrient Retention In A Restored Tidal Freshwater Stream Of The Mid-Atlantic Coastal Plain, Joseph Wood
Theses and Dissertations
Nutrient retention is governed by the interplay between physical processes that control the throughput of water and materials (i.e., water residence time), and by biological processes that govern transformation and uptake (e.g., microbial denitrification). A partial breach of the dam located on Kimages Creek (VA) re-established the historical (pre-1920) connection to the James River and provided a well-defined channel to gauge tidal exchange. We quantified tidal exchange as well as non-tidal (watershed) inputs on a monthly basis to assess Nitrogen (N) retention. Water and N fluxes were dominated by tidal exchange which was typically three times greater than inputs from …
Size-Structured Competition And Predation In Red-Eyed Treefrog Tadpoles, Christopher Asquith
Size-Structured Competition And Predation In Red-Eyed Treefrog Tadpoles, Christopher Asquith
Theses and Dissertations
Body size is important in determining the outcome of competition and predator-prey interactions. Size structure of a population (i.e. relative proportion of large and small conspecifics) may be particularly important in organisms with prolonged breeding periods and rapid growth where populations may have multiple cohorts at different stages of development competing for one resource. Both the consumptive and nonconsumptive effects of predators can also be size-dependent and can alter competitive interactions. Here we study the importance of size structure in the Neotropical leaf-breeding tree frog, Agalychnis callidryas. This species is a prolonged breeder such that multiple overlapping cohorts of differing …