Life Sciences Commons^™

Root Biomass And Production In Four Communities Within The Great Dismal Swamp, Susan West Powell

Biological Sciences Theses & Dissertations

A biomass difference approach was used to measure biomass and production over eleven months in four different communities within the Great Dismal Swamp. On all sites, fine roots were the moat dynamic root component. Both biomass and production were highest on the mixed hardwood site, the least flooded site, and second highest on the cedar site, the site with the longest duration of saturation. The maple-gum and cypress sites had lower amounts of biomass and rates of production. Environmental parameters that influenced production included frequency and duration of flooding, density of the stand, and soil type.

A second method, an …

Assessment Of Lipid Extraction From Human Bone On Subsequent Demineralization, Jaeeun Lee

Biological Sciences Theses & Dissertations

The purpose of this study was to assess the effectiveness of various solvents m removal of lipids from human bone, and to determine the effects of lipid extraction on subsequent acid solubilization of the mineral components of bone. Specifically, the following processing steps were studied; 1) ground human bone was de fatted in various ethanol / water mixtures, and / or chloroform / methanol ( 2: 1, v:v ), 2) ground human bone which had lipids extracted ( in absolute ethanol ) and bone which had not had lipids extracted were demineralized using vanous concentrations of hydrochloric acid to assess …

Activation In Vitro Of Transfer Rna-Guanine Ribosyltransferase By Protein Kinase C, Panayota Eriotou

Chemistry & Biochemistry Theses & Dissertations

The purpose of this study was to isolate and purify the enzymes, transfer RNA-guanine ribosyltrasferase and protein kinase C, and to determine whether the phosphorylating enzyme activates the insertion enzyme in vitro. Transfer RNA-guanine ribosyltransferase lost activity within several days after isolation and total, complete reactivation was accomplished in the presence of protein kinase C. This demonstrated that ribosyltransferase's instability is related to the degree of its phosphorylation. It is proposed that modification of tRNA is controlled by protein kinase C. Deactivation of the insertion enzyme leads to hypomodified tRNA which in turn is associated with neoplasia. Potential use …

The Effects Of Two Polycyclic Aromatic Hydrocarbons Benzo[A]Pyrene And Naphthalene On Reproductive Success Embryological Development Larval Physiology And Mortality Of The Mud Crab Rhithropanopeus Harisii (Gould), Gregory V. White

OES Theses and Dissertations

Polycyclic aromatic hydrocarbons (PAHs) such as naphthalene (Nap) and benzo[a]pyrene (B[a]P) are common in the water column and sediments of estuarine and coastal areas. The mud crab Rhithropanopeus harrisii was exposed to varying concentrations of Nap or B[a]P to determine the effects on reproductive success, embryological development, larval physiology and mortality. Nap and B[a]P decreased hatching success and prolonged embryological development. Both pollutants produced high abnormality frequencies for egg exposed larvae. Molt frequency and respiratory rates of larvae from non-exposed eggs were more chronically affected by these pollutants than were egg exposed larvae. The EC₅₀ concentrations were determined for …

Laminin Potentiates Differentiation Of Pcc4uva Embryonal Carcinoma Into Neurons, T. M. Sweeney, Roy C. Ogle, C. D. Little

Medical Diagnostics & Translational Sciences Faculty Publications

The embryonal carcinoma PCC4uva differentiates into neurons in response to treatment with retinoic acid and dbcAMP. We used this in vitro model system to study the effects of laminin on early neural differentiation. Laminin substrata markedly potentiate neural differentiation of retinoic acid and dbcAMP-treated cultures. Only laminin induced more rapid neural cell body clustering, neurite growth and neurite fasciculation as compared to type IV collagen, type I collagen, and fibronectin substrata. Exogenous laminin substrata promoted greater cell attachment, cellular spreading and growth to confluence than type IV collagen, type I collagen, fibronectin and glass substrata. Laminin-induced effects were inhibited by …

Effects Of Applied Soil Repellent Finish On Pesticide Residues In Work Clothing, Sandra L. Prior

Community & Environmental Health Theses & Dissertations

This study explores the feasibility of using an applied soil repellent finish, Scotchgard, on 100% cotton denim fabric in order to enhance the removal of atrazine and alachlor residue during the laundering process. The experimental findings provided no statistically significant evidence that Scotchgard fabric protector reduced pesticide residuals on the 100% cotton denim fabric either before or after laundering. A significant finding secondary to the study involved the possible interaction of Scotchgard with the pesticide alachlor, leaving greater amounts of residual on the fabric after laundering than those found with no fabric treatment. This suggests that agricultural workers be cautioned …

Small Mammals In The Great Dismal Swamp Of Virginia And North Carolina, Robert K. Rose, Roger K. Everton, Jean F. Stankavich

Biological Sciences Faculty Publications

Small" mammals were surveyed in a range of habitats in the Great Dismal Swamp of Virginia and North Carolina. The survey is based on three chronologically overlapping studies, each lasting 15-18 months and for which the results have been reported separately. A different trapping method was used in each of the three studies: nest boxes, Fitch live traps, or pitfall traps. Only two species of mammals, both arboreal, were taken in nest boxes, compared with 10 and 9 species in Fitch live traps and pitfall traps, respectively. The Fitch live traps had a much higher catch rate per 1,000 trap-nights …

Reproduction In The Hispid Cotton Rat, Sigmodon-Hispidus Say And Ord (Rodentia: Muridae), In Southeastern Virginia, Robert K. Rose, Michael H. Mitchell

Biological Sciences Faculty Publications

The hispid cotton rat, Sigmodon hispidus Say and Ord, a species of the southwestern United States that has been moving northward and eastward in this century, was first observed in Virginia in 1940. In this study of the cotton rat in southeastern Virginia, most males were reproductively competent from February through November, embryos were recorded from March through October, and litter sizes were comparable to those from other locations except Kansas. Also unlike the cotton rat in Kansas, animals grew at substantial rates during the winter in Virginia. The hispid cotton rat seems to have adjusted its breeding season in …

Seasonal And Diel Patterns Of Abundance And Productivity Of Phototrophic Picoplankton In The Lower Chesapeake Bay, Lewis Francis Affronti Jr.

Biological Sciences Theses & Dissertations

This study was performed to evaluate phototrophic pico-plankton (0.2 to 2.0 μm) dynamics within the lower Chesapeake Bay. A 15 month study of phototrophic picoplankton abundance and productivity was made from June 1988 to October 1989. Annual picoplankton abundance using epifluorescence microscopy ranged from 7.26 x 10⁶ cells/1 in the winter to 9.28 x 10⁸ cells/1 during late summer.

In situ incubations of natural picoplankton populations over the 15 month study were used to test the applicability of the frequency of dividing cells technique in estimating phototrophic picoplankton growth rates. The regression equation o fμ = 2.37 x …

Effects Of Chemical Aneuploidogens On Taxol Purified Drosophila And Mouse Brain Microtubules Polymerization And Depolymerization In Vitro, Anil Sehgal

Biological Sciences Theses & Dissertations

The effects of aneuploidogens (aneuploidy causing agents) on taxol-purified microtubules from Drosophila and mouse brain in vitro were studied by using a spectrophotometric assay and electron microscopy. Colchicine, acetonitrile, propionitrile, acrylonitrile, dimethyl sulfoxide (DMSO), griseofulvin and cadmium chloride inhibited microtubule polymerization whereas methoxyethyl acetate (MEA) and methyl mercuric chloride (MMC) did not. All aneuploidogens tested (at 50mM) resulted in reduced rate of elongation of mouse brain microtubules. MMC, cadmium chloride and DMSO resulted in increased rates of Drosophila microtubule elongation whereas the rest of the drugs resulted in decreases. The in vitro results from Drosophila correlate well with the previously …

Evidence Of A Neurogenic Component During Ige-Mediated Inflammation In Murine Skin, Victoria Jean Cavanaugh

Biological Sciences Theses & Dissertations

The direct stimulation of sensory nerves or the intradermal injection of neuropeptides triggers a cutaneous inflammatory response that involves the degranulation of mast cells. These neurogenic inflammatory reactions are physiologically similar to IgE-mediated hypersensitivity responses, which also depend on mast cells. Although non-antigenic stimuli distinguish neurogenic from IgE-mediated inflammation, the similarity of their effector stages suggested that peripheral nerves may also participate in lgE-mediated responses. To examine this hypothesis, IgE responses were elicited in denervated skin. A murine model was developed where the footpad was denervated by surgically removing a 2 mm segment of the sciatic nerve, proximal to the …

Microwell Based Solid Phase Competitive Enzyme Immunoassay For Estradiol And Estriol, Jeng-Ting Yang

Chemistry & Biochemistry Theses & Dissertations

A sensitive and simple microwell based competition enzyme immunoassay for the quantitative determination of estradiol (E₂) and estriol (E₃) was developed. Nicrowells coated with antibody were incubated with antigen followed by adding horseradish peroxidase (HRPO) conjugate. The assay, which can be performed within two hours at room temperature, involved simultaneous incubation of E₂ - or E₃-HRPO conjugate and serum sample in polystyrene microwells coated with anti- E₂ or anti-E₃ gamma globulin fraction.

Gamma globulin was isolated from whole anti-serum by DEAE-cellulose chromatography. A carbodiimide coupling method was utilized to prepare the …

Separation Of Transfer Rna Isoacceptors By Reversed Phase W-Porex C-4 High Pressure Liquid Chromatography, Christine D. Witte

Chemistry & Biochemistry Theses & Dissertations

Transfer RNA (tRNA), is a complex class of small molecules which have been proven to play a major role in protein synthesis. Transfer RNA is composed of 20 families of isoacceptors which may recognize only one particular amino acid. This family of isoacceptors may differ from each other by primary sequence or modified nucleosides. Queuine is a modified nucleoside which is found in the anticodon regions of tRNA isoacceptors for asparagine, aspartic acid, tyrosine and histidine. Queuine has gained the interest of many researchers since queuine deficient tRNA was found in many neoplastic and undifferentiated cell-lines. It is often difficult …

Development Of A Solid Phase Enzyme Immunoassay For Total Serum Testosterone, Li Li

Chemistry & Biochemistry Theses & Dissertations

An enzyme-labeled immunoassay of sufficient range and sensitivity was developed for serum testosterone determination. In this method, the testosterone in the serum sample and testosterone-HRPO conjugate compete with each other for the limited antibody binding sites on the anti-testosterone gamma globulin coated microwell. The assay can be performed in only 2.5 hours.

The gamma globulin fraction was isolated from the anti-testosterone whole serum by DEAE-cellulose column chromatography. Testosterone-peroxidase conjugate was prepared by a carbodiimide coupling method. The interference which arises from the binding of testosterone to steroid hormone binding protein was eliminated by the addition of 17 beta-estradiol. All assay …

An Autecological Study Of Pyxidanthera Barbulata In The Blackwater Ecologic Preserve Virginia, John Marc Lowenthal

Biological Sciences Theses & Dissertations

Pyxidanthera barbulata (pyxie moss), a rare and endangered subshrub, has been found in decreasing numbers in it's "pine barren" habitat. An autecological study encompassing vegetation association analysis and environmental measurements was performed in the Blackwater Ecologic Preserve, its only known location in Virginia. The preserve is being subjected to controlled burning and the effect of burning on the species was evaluated. A multivariate analysis of variance was performed to identify species associations, and simple analysis of variance was done to find trends in the environmental data. Four taxa were positively associated with P. barbulata, Gaultheria procumbens, Vaccinium tenellum, Cladonia spp., …

The Determination Of Clomiphene Citrate And Tamoxifen In Human Blood Plasma And Semen, Janice Irene Kiss

Chemistry & Biochemistry Theses & Dissertations

Triphenylethylene antiestrogen compounds are used to stimulate ovulation in anovulary women and spermatogenesis in oligozoospermatic males. Clomiphene Citrate (CC) is given therapeuticaly as a mixture of the trans (E) and cis (Z) isomers. Each of these isomers has its own characteristic agonist-antagonist profiles. Only the trans form of Tamoxifen (T) is administered therapeutically.

HPLC methodologies were developed for the determination of CC and Tin human blood and seminal plasma. The methodologies involved extraction of the triphenylethylene compounds using hexane, followed by evaporation of the hexane under N₂. The residue was then taken up in a volume of HPLC …

Phytoplankton In Lake Drummond And Two Drainage Ditches In The Great Dismal Swamp, Virginia, Christine Gregory Phillips

Biological Sciences Theses & Dissertations

A twelve month study was conducted on the phytoplankton of Lake Drummond and Washington and Jericho Ditches from December 1988 to November 1989. Surface water samples were collected for nutrient and chlorophyll analysis from June 1989 to November 1989. The dominant phytoplankton component was the pico-nanoplankton (< 3 micron) category. A total of 57 species were identified from Lake Drummond, 51 species from Washington Ditch, and 31 species from the Jericho Ditch. Three major phytoplankton groups were identified at these sites: bacillariophyceans, cyanophyceans and cryptophyceans. The dominant species was the diatom Asterionella formosa. Nutrient and chlorophyll concentrations increased from summer to fall. Based on nutrient and chlorophyll g concentrations and species diversity indices, Lake Drummond is classified as eutrophic.

Morphological And Physiological Examination Of A Demyelinating And Remyelinating Lesion, Paul Anson Felts

Theses and Dissertations in Biomedical Sciences

Multiple sclerosis causes demyelination of central nerve fibers, and it is this pathology which results in most of the symptoms of the disease. The repair of the fibers by remyelination has been advanced as a potential symptomatic therapy, but at present the conduction properties of remyelinated central fibers are not well understood. In this study the conduction properties of Schwannian or oligodendrocyte remyelinated central nerve fibers have been determined. In addition, the status of the blood-brain barrier has been examined in lesions characterized by Schwann cell remyelination. These lesions chronically lack astrocytes, a cell believed to be involved in the …

An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy

Biological Sciences Theses & Dissertations

Reproductive status in specimens of nine populations of seven species of small mammals was evaluated by examining the external reproductive features of nipple size, condition of the pubic symphysis, and vaginal condition and, in males, testis position. Usefulness of these external features in predicting true monthly breeding rates was evaluated by comparing predictions of breeding rates with true rates based on necropsy. Accuracy of predictions of reproductive status of individuals based on single external features and combinations of external features and body measurements was then analyzed at a finer level by comparing those predictions with results of necropsy of the …

Comparison Of The Protein Content In Selected Tissues At Different Feeding Stages In The American Dog Tick Dermacentor Variabilis (Say), Mark John Beveridge

Biological Sciences Theses & Dissertations

Selected tissues from Dermacentor yariabilis (Say) were collected at different feeding stages (unfed, part-fed, and replete) and examined by several different protein analyses to determine soluble protein content, protein or polypeptide molecular weights, and pI values. Results showed a relationship between the salivary gland, ovary and hemolymph and evidence indicates the synganglion produces and secretes substances that may control oocyte development.

The Role Of The Voltage Gradient In The Agarose Gel Electrophoresis Of Dna, David Wheeler

Theses and Dissertations in Biomedical Sciences

In Part I of this dissertation, empirical equations for predicting DNA mobility during agarose gel electrophoresis (AGE) from voltage gradient are developed from the data of McDonnel (36) for electrophoresis in a 1.6% agarose gel. These equations represented the data well for DNA between 2 and 10 kilobase pairs (KBp) in length. A computer program, called GELSIM, which incorporates these equations is described in Part II. GELSIM was designed to allow researchers to analyze electrophoresis data by predicting the effect on DNA migration of altering the voltage of electrophoresis. In this way, electrophoretic banding patterns produced using different voltages could …

A Study Of Striga Chromosome Numbers With A Comparison To Those Of Some Genera In The Rhinathoideae And The Orobanchaceae, Cynthia White

Biological Sciences Theses & Dissertations

New chromosome counts are given for nine species of Striga including S. elegans (n=18), S. asiatica (n=19), S. forbesii (n=22), S. densiflora (n=26), S. aspera (n=27), S. passargei (n=28), and S. hermonthica (n=30). Previous counts reported for S. gesnerioides (n=20) and S. angustifolia (n=20) are verified. Evidence from the base number (x=10), chromosome counts, and differences in chromosome size (bimodality) suggests that the genus is an allotriploid with a descending aneuploid series. Genomic change appears to occur by different mechanisms in the Rhinanthoideae; some genera display a euploid series, others show aneuploidy, and some are very stable. Genera examined …

Progesterone And 17 Α-Hydroxyprogesterone: Novel Stimulators Of Calcium Influx In Human Sperm, Peter F. Blackmore, Stephen J. Beebe, Douglas R. Danforth, Nancy Alexander

Bioelectrics Publications

Progesterone and 17 alpha-hydroxyprogesterone (but not other steroids such as testosterone, corticosterone, beta-estradiol, estrone, dehydroepiandrosterone, 20 alpha-hydroxypregnen-3-one, androstenedione, and pregnenolone) were shown to cause an immediate increase, in free cytosolic calcium ([Ca2+]i) in both capacitated and noncapacitated human sperm, using the fluorescent indicator fura 2. Significant increases in [Ca2+]i were observed with 10 ng/ml progesterone, while maximum effects were seen with 1 microgram/ml progesterone. Two other steroids 11 beta-hydroxyprogesterone and 5 alpha-pregnane-3,20-dione exhibited significant activity to increase [Ca2+]i. This increase in [Ca2+]i elicited by progesterone was entirely due to Ca2+ influx from the extracellular medium since the increase in [Ca2+]i …

Estimates Of Spawning Stock Size Of Blue Crab, Callinectes Sapidus, In Chesapeake Bay, 1986-1987, Cynthia M. Jones, John R. Mcconaugha, Patrick J. Geer, Michael H. Prager

OES Faculty Publications

The 1986 spawning stock exhibited a single abundance peak, increasing from 1.0×105 individuals in early July to 9.3×106 in late July, maintaining high levels throughout the summer, and declining in the fall to 7.4×105 individuals. The 1987 spawning stock showed 2 peaks of abundance. The population reached the lesser peak, 1.0×106 individuals, in late July; the greater peak, 1.5×106, in late August. By late September, the population had declined to 6.5×105 individuals. The peak abundance of the 1987 female spawning stock was only 16% as great as the peak abundance in 1986; the 1987 spawning stock size in 1986. Variability …

Fecundity Of Blue Crab, Callinectes Sapidus, In Chesapeake Bay: Biological, Statistical And Management Considerations, Michael H. Prager, John R. Mcconaugha, Cynthia M. Jones, Patrick J. Geer

OES Faculty Publications

Ovigerous blue crabs were collected from the mouth of Chesapeake Bay during the 1986 and 1987 spawning seasons. Mean carapace width was 14.7 cm; mean fecundity was 3.2×106 eggs. Fecundity was significantly related to carapace width, and did not vary significantly with developmental stage of the eggs. Mean fecundities were 2.6×106 eggs in 1986, and 4.0×106 eggs in 1987. An additive model with year and size effects described the observed fecundities reasonably well, was compact, and was easier to interpret than a multiplicative model. To fit a more general model without year effects, the authors took the mean of 1986 …

Investigations Of The Trophic Relationships, Feeding Ecology And Feeding Behavior Of Larval Spot, Leiostomus Xanthurus Lacepede, And Atlantic Croaker, Micropogonias Undulatus (Linnaeus) (Pisces:Sciaenidae), Dirk Edward Peterson

Biological Sciences Theses & Dissertations

The feeding ecology of preflexion and flexion-postflexion spot (Leiostomus xanthurus) and Atlantic croaker (Micropogonias undulatus) larvae was evaluated and compared. Nutritional condition of spot larvae from the Gulf of Mexico was high, with no larvae classified as starving. This was probably due to an inability to sample starving larvae at sea because of predation pressure or was indicative of favorable feeding conditions and an absence of starvation in the collection area. In spite of morphological similarities between the species, significant differences in body shape existed.

The diets of the two species converged with age and interspecific dietary overlap was relatively …

The Role Of Small Peptides In Cancer Physiology And Chemotherapy, Bao-Ling Tsay

Theses and Dissertations in Biomedical Sciences

The targeting of proven anticancer drugs specifically to cancer cells would provide a unique opportunity to restrict neoplasms without damaging the cancer patient. The present research utilizes the phenomenon of illicit transport, i.e. the coupling of normally impermeant metabolites to permeant metabolites, in targeting the drug melphalan to mouse Ehrlich ascites tumor cells. The dipeptide beta-alanyl-melphalan was synthesized and tested in vitro for toxicity towards mouse Ehrlich ascites tumor cells, mouse liver cells, and mouse 3T3 embryonic cells. The parent compound, melphalan, was used as a control treatment. In addition, both melphalan and beta-alanyl-melphalan were utilized in in vivo chemotherapeutic …