Life Sciences Commons^™

Cytokine Expression By T. Helper Cells Responding To Stress, Dina Zanetti

Master's Theses

Stress causes alterations to the immune system. These alterations have lead to increased susceptibility to antigens. The present study explores shifts in T helper (TH) cell balance (TH1 and TH2), through their cytokine expression. This study was performed in three phases, and focused mainly on animals subjected to a 10 day a chronic unpredictable stress paradigm. Phase one used ELISAs to confirm the cytokine profile produced from TH 1 and TH2 murine cell-lines. Phase two used SDS PAGE and Western Immunoblotting to show that splenocytes from Long Evan's Hooded rats subjected to the stress paradigm, had decreased in intercellular in …

The Status Of Leptodactylus Validus As A Single Taxon And Its Relationship To Letptodactylus Pallidirostris, Kenneth Christopher Yanek

Master's Theses

Leptodactylus validus exhibits an unusual distribution inhabiting Trinidad, Tobago, and the Lesser Antilles, but not the mainland of South America. This distribution is inconsistent with other distribution patterns observed for these islands. Although slight variation in adult morphology has been observed among the island populations, call data suggest the presence of a single species. Calls of Leptodactylus pallidirostris from Venezuela suggested that this taxon might be conspecific with L. validus. Herein sequence data from the 12S and 16S mt rRNA genes were collected and analyzed in order to address: 1.) whether more than one species is represented within L. validus, …

Acalypha Deamii : Distribution East Of The Appalachians And Comparative Studies Of Reproductive Anatomy, Patricia A. Truman

Master's Theses

Acalypha deamii (Euphorbiaceae), once thought restricted to flood plains of the Ohio and mid-Mississippi River systems, is now documented from similar habitats in Virginia, Maryland, and West Virginia along the James, Potomac, Rappahannock, Roanoke (Staunton), and Shenandoah rivers. This species is recognized by two-carpellate gynoecia, large seeds, and the routine occurrence of allomorphic flowers and fruits, features sporadically found within this large genus. In addition to documenting the newly recognized range extension of Acalypha deamii, this thesis also investigates the nature of its allomorphic reproductive structures. Staminate, pistillate, fruiting, and allomorphic reproductive structures of Acalypha deamii and a closely related …

A Mitochondrial Dna Phylogeny Of The Leptodactylus Fuscus Species-Complex (Leptodactylidae: Anura, Arley Camargo

Master's Theses

Leptodactylus fuscus is a broadly distributed frog species in the Neotropical region. Previous allozymic evidence supported the hypothesis of L. fuscus as a composite of several species. However, morphological and advertisement call data supported the hypothesis of a single-species taxon. These competing hypotheses were evaluated using cladistic analyses of mitochondrial DNA sequences. Fragments of 12S rRNA, 16S rRNA, and ND1 protein-coding genes from 17 populations were sequenced. Phylogenetic analyses were performed using: maximum parsimony, maximum likelihood, and Bayesian analysis. Data sets were analyzed separately and combined. Analyses of the combined data set show four exclusive clades of L. fuscus: …

Storm-Related Suspended Particulate Matter In Little Westham Creek, John R. Jordan

Master's Theses

Properties of a watershed regulate the amount of suspended particulate matter (SPM) in a stream. The present study examined relationships between storm-related SPM and impervious area and tree cover in the suburban watershed of Little Westham Creek, Richmond, Virginia during Summer and early Fall, 1999. SPM concentration, SPM discharge, and turbidity due to clay, silt and sand, and the areas of impervious surface and tree stand cover in the watershed were measured at three sites. SPM concentration, SPM discharge, and turbidity due to clay were greater upstream than downstream. The percentages of watershed area covered by impervious surfaces and tree …

A Quantitative Histological Evaluation Of Articular Cartilage And Regenerated Tissue From A Stress-Shielded In Vivo Model, Jeremy Matthew Kupsco

Master's Theses

Cartilage does not normally repair lesions. Cartilage induced to regenerate experimentally degenerates quickly, perhaps because stresses of articulation do not allow normal extracellular matrix to develop. I examined normal cartilage from dogs, pigs, rabbits, and humans, and canine patellar tissue regenerated in a stress-shielded environment. SEM of canine cartilage after trypsin digestion revealed meshworks of fibrils oriented with a bias normal to the surface in the deep zone, random in the middle zone, and parallel to the surface in the superficial zone. SEM after freeze-fracture revealed tubules of fibrils within the deep zone. I found no evidence of collagen arcades. …

The Role Of Matrix Metalloproteinase-2 In Glioma Invasion, Nicole Danielle Sauers

Master's Theses

Overexpression of matrix metalloproteinase 2, MMP-2, is correlated with highgrade gliomas in vivo. The purpose of this study was to investigate whether MMP-2 overexpression in glioma cell lines leads to increased invasion of glioma cells in vitro. The entire MMP-2 gene was isolated from U87, a glioma cell line known to have high expression of wild-type MMP-2. This :tvIMP-2 gene was inserted in a sense and antisense orientation into pCR3 .1 vectors with a CMV promoter to ensure high levels of expression. Glioma cell lines were transfected with the sense and antisense constructs, as well as the pCR3.l vector alone …

An Ulstrastructural Study Of Acetabularia Acetabulum, Rachel Vangilder

Master's Theses

Calcification within the cell and the cell wall Acetabularia acetabulum, a large single cell alga, is examined through an ultrastructural investigation, electron diffraction, and an elemental analysis. These methods suggest that amorphous calcium carbonate is located adjacent to and within the cell wall. The location of the crystals within and directly outside the cell wall suggests the calcium is obtained from the surrounding environment. Fibrillar structures are seen through SEM in areas where calcification is occurring. This fibrillar material appears to serve as the organic matrix where calcification initiates. Intracellularly electron dense materials is seen in the chloroplasts. This …

Transplanting Broodstock Oysters, Crassostrea Virginica, Onto Reconstructed Oyster Reefs To Increase Spat Recruitment In The Piankatank River, Dawn Chentil Sherwood

Master's Theses

Four oyster reefs were recreated from oyster shells to historical proportions in the Piankatank River from 1993-1995. In December 1997, two of the reconstructed reefs were supplemented with large broodstock oysters from Tangier and Pocomoke Sounds. Since total quantity as well as density ofbroodstock were believed to be limiting factors for recruitment in this river, adding stock was expected to raise spat recruitment. Methods included dive surveys on the reefs, and dredge and patent tong surveys on the natural oyster bars. The recruitment of spat to both reefs and bars was significantly higher in 1998 (p<0.001) than in the previous four years and a positive interaction (p<0.005) was seen between the reefs and the year 1998. Based on these dat~ stock enhancement in the Piankatank River successfully improved recruitment and suggest oyster restoration may be facilitated in other areas of the Chesapeake Bay by strategic enhancement of spawning stocks.

Chondrocranial And Oral Morphology Of Leptodactylid Larvae, William Hagood Turner

Master's Theses

I focused my research on Leptodactylidae in order to determine the usefulness of chondrocranial and internal oral characters in systematic and phylogenetic studies of this anuran family. To achieve this goal, I examined the chondrocrania of eight species of the Leptodactylinae: Adenomera marmorata, Edalorhina perezi, Limnomedusa macroglossa, Physalaemus gracilis, P. henselii, P. pustulosus, Pleurodema brachyops, and P. tucumana. Furthermore, I analyzed and described the internal oral anatomy of Physalaeum us gracilis, P. henselii, and Limnomedusa macroglossa and the skeletogenesis of P. gracilis and P. pustulosus. Subsequently, I integrated these data with all available data on the larval chondrocrania and internal …

Area-Species Curve Applies To Gaps In A Canada Hemlock (Tsuga Canadensis (L.) Carr.) Forest In The Shenandoah National Park, Joseph John Lacroix

Master's Theses

A typical area-species curve shows that species richness (number of species) and island size are positively correlated. I tested whether the area-species concept, which was developed using islands, could be applied to herbaceous plants in canopy gaps in a hemlock community.

I conducted studies in Limberlost, Shenandoah National Park. I measured the species richness of herbaceous plants in six gaps during the summer and fall of 1995 and eight gaps and one non-gap site in the spring of 1996. The two additional gaps in 1996 extended the upper range of gap sizes. I calculated the correlation between species richness and …

Chondrocranial And Oral Morphology Of Pipoid Frogs, Charles Christopher Swart

Master's Theses

The Pipoidea are a diverse group of frogs. Their diversity is demonstrated in their morphology, ecology, and behavior. One pipoid species, Xenopus laevis, has been used as a model system of developmental, physiological, and molecular studies of vertebrates. My work has focused on the developmental morphology of the chondrocranium and oral morphology of four pipoid taxa: Hymenochirus boettgeri, Rhinophrynus dorsalis, Pipa carvalhoi, and Xenopus laevis. Previous studies have suggested that the Anura may be diphyletic based on the unique characteristics of the chondrocanial morphology of pipoids. The chondrocranial and internal oral morphology of the pipoids indicates that as a group …

Sequence Characterization And Phylogenetic Analyses Of The Pol Region From Sire-1, An Endogenous Retrovirus From Glycine Max, Eric A. Gaucher

Master's Theses

No abstract provided.

Isolation And Characterization Of A Genomic Clone For A Nitrate Reductasae Isoform From Soybean, Glycine Max, Brent Chyna

Master's Theses

No abstract provided.

A Profile Of Antibiotic Resistant Bacteria In The James River, Keith Allen Boisvert

Master's Theses

Spatial and temporal variability in the antibiotic resistance of bacterial assemblages in the lower portion of the James River was examined. The antibiotic resistance of culturable coliforms was compared to the resistance in the microbial community. Antibiotic resistance was determined via colony formation on media containing antibiotics. The antibiotics ampicillin, chloramphenicol, streptomycin and tetracycline were used at concentrations ranging from 10 to 500 ug/ml. Statistically significant differences in the mean number of antibiotic resistant isolates were observed among both sample sites and dates. The sampling site at river mile 99 just below Richmond showed both increased antibiotic resistance and bacterial …

Semipermeable Membrane Devices Are Effective Surrogates Of Fish In Concentrating Polychlorinated Biphenyls, Christopher Gardner Collins

Master's Theses

This study examined the effectiveness of Semipermeable Membrane Devices (SPMDs) as surrogates for fish in concentrating polychlorinated biphenyls. Golden shiners (Notemigonus crysolucas) and SPMDs were exposed to three different concentrations (0.5, 1.5, and 3.0ppm) of Aroclor 1254 for 1, 3, and 5 days under laboratory conditions. Concentrations of Aroclor 1254 were measured in the SPMDs and fish tissue using extraction techniques and gas chromatography. The concentrations of PCB in SPMDs and N. crysolucas were positively correlated. This relationship compared favorably with data from other studies. The relationship between the concentration of PCB in SPMDs and tissue offish and …

The Soybean Retroelement, Sire-1, Encodes An Envelope-Like Protein-Sire-1 Is An Endogenous, Proretrovirus-Like Genomic Element, Arpita Majumdar

Master's Theses

No abstract provided.

Analysis Of The Inheritance Repression Of A Transposable Element In Drosophila Melanogaster, Melissa Leone

Master's Theses

No abstract provided.

Regulation Of The Activities Of The Three Nitrate Reductase Isoforms In Wild-Type Soybean Glycine Max (L.) Merr. (Variety Williams) By Protein Phosphorylation, Maribel T. Joson

Master's Theses

No abstract provided.

Benthic Invertebrate Community Responses To Round Goby (Neogobius Melanostomus) And Zebra Mussel (Dreissena Polymorpha) Invasion In Southern Lake Michigan, Linda A. Benning

Master's Theses

No abstract provided.

Characterization Of Deletion Sites In A Human Collagen-Like Locus, Marissa A. Michaels

Master's Theses

No abstract provided.

Saccharomyces Cerevisiae-Produced Recombinant Pfs230: A Malaria Transmission-Blocking Vaccine Candidate, Kathryn M. Glynn

Master's Theses

No abstract provided.

The Effects Of 2,4-Dichlorophenoxyacetic Acid On The Diazotrophic Soil Microbial Community, Denise M. Brown

Master's Theses

This study measures the effects of 2,4- dichlorophenoxyacetic acid (2,4-D) on growth and nitrogen fixation capabilities of the native microbial soil community during eight field trials conducted over an eight month period. After application of 2,4-D, soil samples were analyzed for enumeration of diazotrophic and general microbial communities, and for nitrogenase activity as measured by the acetylene reduction assay (ARA). Statistical analyses were conducted using Minitab. Results show that 2,4-D significantly stimulated growth of diazotrophic microbes in 87.5% of the trials and was found to have a stimulatory growth effect on the general microbes in 62.5% of the trials. A …

The Effect Of Thyroid Hormone On The Expression Of A7 Myosin Heavy Chain Mrna In Xenopus Laevis, Bradley Thomas Butkovich

Master's Theses

It has long been known that thyroid hormone (TH) is responsible for metamorphosis in tadpoles. It is also known that A7 MHC, an adult muscle isoform, is expressed in adult Xenopus laevis frogs, but not in larvae. Furthermore, the appearance of A7 corresponds with the onset of metamorphosis. The present study investigated the relationship between TH and the expression of A7 MHC mRNA in Xenopus laevis. Isolated tails in culture and 6-n-propyl 2-thiouracil (PTU) treated tails were treated with TH and the presence of A7 mRNA analyzed with in-situ hybridization, and RT-PCR. It was found that TH caused substantial …

Osteology, Morphology, And Female Choice In Species Of The Genus Cynolebias (Cyprinodontiformes: Rivulidae), Marcelo Loureiro Barrella

Master's Theses

Relationships among the species of the annual fish Cynolebias are unclear. An analysis of the utility of different osteological and morphological characters for phylogenetic analyses was done using clear and double stained specimens and measurements of morphometric parameters respectively. Scanning electron microscopy was used to study the morphology of the egg chorion. Female choice tests were also conducted to test male traits that may be preferred by females. The osteological analysis showed that some characters previously unreported may be phylogenetically useful. Head scalation patterns were found to be intraspecifically variable, making them inappropriate to use in systematics. Each morphometric parameter …

Feasibility Of Stocking Grass Carp (Ctenopharyngodon Idella; Cyprinidae) To Control Hydrilla (Hydrilla Verticillata; Hydrocharitaceae) In Lake Anna, Virginia, Paul Matthew Overton

Master's Theses

The goal of this study was to demonstrate the feasibility of using triploid ·Ctenopharvngodon idella (grass carp) to control Hydrilla verticillata in the Waste Heat Treatment Facility (WHTF) in Lake Anna, Virginia. The four objectives were to determine: the frequency of occurrences of grass carp over hydrilla; the proportions of hydrilla to other aquatic macrophytes in the guts of grass carp; effects of physical and chemical factors on movement of grass carp; and a theoretical stocking rate of grass carp for the WHTF. Frequency of occurrence of grass carp over hydrilla was calculated to be 84% and correlated with impoundment …

Characterization Of A Newly Cloned Dna Damage- Inducible Gene From Saccharomyces Cerevisiae Strain D43, June-Home Chen

Master's Theses

The identification and characterization of DNA damage-inducible genes is an important topic in the study of the integrity of the cellular genome. Previously, a TnlO-lacZ derivative was inserted randomly into yeast cells and the resulting mutants were screened for insertions in DNA damage-inducible genes. S. cerevisiae strain D43 was identified as one such TnlO-lacZ insertion mutant. DNA sequencing results show the insertion in D43 is located within the TDH2 gene, which encodes glyceraldehyde-3-phosphate dehydrogenase. Treatment of strain D43 with DNA damaging agents and heat shock suggest TDH2 is responsive to DNA damage, but not to heat shock. Haploid mutants carrying …

Density Dependent Limitations And Vertical Position Of Diatoms In A Periphyton Mat, Ronald E. Johnson

Master's Theses

No abstract provided.

The Role Of Protein Kinases In The Regulation Of The Na+/H+ Antiporter In Xenopus Oocytes, Andre P. J. Kulisz

Master's Theses

No abstract provided.

Sculpins As Predators Of Lake Trout Eggs And Larvae: An Assessment Of Their Predatory Capabilities And Constraints, Heather C. Biga

Master's Theses

No abstract provided.