Life Sciences Commons^™

Regulation Of Algal Blooms In Antarctic Shelf Waters By The Release Of Iron From Melting Sea Ice, Peter N. Sedwick, Giacomo R. Ditullio

OES Faculty Publications

During summer 1995-96, we measured iron in the water column and conducted iron-enrichment bottle-incubation experiments at a station in the central Ross Sea (76°30'S, 170°40'W), first, in the presence of melting sea ice, and 17 days later, in ice-free conditions. We observed a striking temporal change in mixed-layer dissolved iron concentrations at this station, from 0.72-2.3 nM with sea ice present, to 0.16-0.17 nM in ice-free conditions. These changes were accompanied doubling of algal (diatom) biomass. Our incubation experiments suggest that conditions were iron-replete in the presence of sea ice, and iron-deficient in the absence of sea ice. We surmise …

Yield-Per-Recruit Analysis And Management Strategies For Atlantic Croaker, Micropogonias Undulatus, In The Middle Atlantic Bight, Luiz R. Barbieri, Mark E. Chittenden, Cynthia M. Jones

OES Faculty Publications

The effect of different fishing mortality (F) and natural mortality (M), and age at first capture (t(c)) on yield-per-recruit of Atlantic croaker, Micropogonias undulatus, in the lower Chesapeake Bay and North Carolina were evaluated with the Beverton-Holt model. Independent of the level of M (0.20-0.35) or F (0.01-2.0) used in simulations, yield-per-recruit values for Chesapeake Bay were consistently higher at t((c)) = 1 and decreased continuously with increases in t(c) (2-5). Although maximum yield-per-recruit always occurred at the maximum level off (F=2.0), marginal increases in yield beyond F = 0.50-0.75 were negligible. Current F (F(CUR)) is estimated to be …

Age And Growth Of Larval And Juvenile Atlantic Croaker, Micropogonias Undulatus, From The Middle Atlantic Bight And Estuarine Waters Of Virginia, Stephen W. Nixon, Cynthia M. Jones

OES Faculty Publications

Sagittal otoliths were used to determine age and growth of 605 larval and juvenile Atlantic croaker, Micropogonias undulatus, collected in the Middle Atlantic Bight and estuarine waters of Virginia. This study is the first to use age-based analysis for young Atlantic croaker collected in this region. A Laird-Gompertz model (r2=0.95) was used to describe the growth of Atlantic croaker up to 65 mm standard length (SL) and 142 days (t): SL((t)) = 2.657 exp (4.656 [1-exp (-0.0081t)]); where SL((t)) = standard length at day t. Spatial and temporal patterns in the size and age of Atlantic croaker showed a …

Response Of Otolith Microchemistry To Environmental Variations Experienced By Larval And Juvenile Atlantic Croaker (Micropogonias Undulatus), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana

OES Faculty Publications

Minor and trace elements incorporated into otoliths during growth may permanently record environmental conditions experienced by fishes. To determine the validity of this approach, we used laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to assay sectioned otoliths from juvenile Atlantic croaker (Micropogonias undulatus) collected from each of three sites in the Neuse River, North Carolina, and the Elizabeth River, Virginia. Elemental concentrations at the center of the otoliths did not differ between locations, although both Mg : Ca and Ba : Ca were significantly higher at the edge of otoliths from the Neuse River than from the …

Destruction Of Chloropigments In Copepod Guts, A. B. Bochdansky, D. Deibel

OES Faculty Publications

In a recent account regarding the destruction of chloropigments within the guts of copepods, Head & Harris (1996) (H&H) presented valuable data on pigment destruction in copepods. However, in one of their main conclusions, the authors invoked 2 enzyme pools to explain the pattern of pigment destruction: one directly derived from copepods, the other one produced by the ingested algae. If this conclusion is correct, it would have tremendous impact on the interpretation of data collected by the gut pigment technique. Estimating ingestion rates of copepods in the field would be very difficult, if not impossible, if pigment destruction was …

Evaluation Of The Effects Of Afff Inputs On The Vip Biological Nutrient Removal Process And Pass-Through Toxicity. Phase 1a. Volume Ii. Appendix Vii. Acute Toxicity Test Results, Mujde Erten-Unal, Gary C. Schafran

Civil & Environmental Engineering Faculty Publications

This report discusses the results of a bench scale study conducted to evaluate the potential inhibitory effects of untreated AFFF wastewater to the Virginia Initiative Plant VIP biological nutrient removal process. A bench-scale study was conducted to evaluate the potential inhibitory effects of untreated AFFF wastewater to the nitrification process of the Virginia Initiative Plant biological nutrient removal system. Under this testing, bench-scale reactors simulating the nitrification process were loaded at various AFFF concentrations and the influence on the process performance was evaluated. The purpose of this effort was to determine the level of AFFF that could be incorporated into …

Pseudoreplication Revisited, Robert A. Heffner, Mark J. Butler Iv, Colleen Keelan Reilly

Biological Sciences Faculty Publications

No abstract provided.

Modeling Nutrient And Plankton Processes In The California Coastal Transition Zone: 3. Lagrangian Drifters, J. R. Moisan, Eileen E. Hofmann

CCPO Publications

Two types of numerical Lagrangian drifter experiments were conducted, using a set of increasingly complex and sophisticated models, to investigate the processes associated with the plankton distributions in the California coastal transition zone (CTZ). The first experiment used a one-dimensional (1-D; vertical) time-dependent physical-bio-optical model, which contained a nine-component food web. Vertical velocities, along the track of simulated Lagrangian drifters, derived from a three-dimensional (3-D), primitive equation circulation model developed to simulate the flow observed within the CTZ; were used to parameterize the upwelling and downwelling processes. The second experiment used 880 simulated Lagrangian drifters from a 3-D primitive equation …

The Diet Of Oryzomys Palustris Based On Stomach Content Analysis, Shannon L. Wright

Biological Sciences Theses & Dissertations

Oryzomys palustris (Harlan) is unusual in that it is one of two carnivorous mammals in the Family Muridae in North America. A diet analysis of Oryzomys palustris. the marsh rice rat, was done based on stomach contents. This was accomplished by taking the animals from two study areas located on the Eastern Shore of Virginia. The animals were taken monthly for one year. Once caught, the animals were sacrificed and their stomach contents were identified to the lowest taxonomic level possible. This study showed that rice rats were omnivorous mammals, eating a variety of foods, including dicots, monocots, crabs, …

Brown-Headed Cowbird (Molothrus Ater) Range Expansion Into The Southeast: Effects On The Passerine Populations Using North American Breeding Bird Survey Data, Elizabeth Pruitt Henderson

Biological Sciences Theses & Dissertations

North American Breeding Bird Survey data that were collected from 1971-1992 in Virginia, North Carolina, south Carolina, Georgia, Florida, Alabama and Tennessee were used in this analysis of the impact of Brown-headed Cowbird range expansion on four warbler and four vireo host species.

Maps of mean cowbird abundances were produced using kriging for the periods 1971-1975, 1976-1980, 1981-1985, 1986-1990 and 1991-1992. These maps illustrated a complex invasion of the southeastern United States by Brown-headed Cowbird.

Linear regression analyses of host and cowbird abundances within physiographic strata, showed no species to be in decline or increasing in abundance over the entire …

Characterization Of P39, A Borrelia Burgdorferi Specific Protein, Jill M. Troyer

Theses and Dissertations in Biomedical Sciences

Borrelia burgdorferi, the causative agent of Lyme disease, expresses a species specific, 39 kiloDalton protein of unknown function called P39. This protein is highly immunogenic and the presence of anti-P39 antibodies in patient sera is used as an indicator of B. burgdorferi infection. P39 is also a candidate for vaccine developement due to conserved expression of P39 among B. burgdorferi isolates. Since little is presently known about this important molecule, the present study was designed to characterize P39 and was carried out in six separate investigations. First, infectious and noninfectious isolates of B. burgdorferi were established in vitro, and …

Human Immunodeficiency Virus (Hiv)/Hepatitis B Virus (Hbv) Risk Perception Related To Needlestick Injuries At A Medical School In Norfolk, Virginia, Ronald B. Hartman

Community & Environmental Health Theses & Dissertations

A limited number of studies have been conducted to assess the perceptions of risk of medical students and residents for acquiring Human Immunodeficiency Virus (HIV) or Hepatitis B Virus (HBV) via percutaneous (needlestick) injuries while performing clinical training. The purpose of this study is to investigate these perceptions of risk, and to determine whether there is an association between a high perception of risk and a low incidence of needlestick injury. The method of investigation was a four-page survey questionnaire. The instrument was investigated for reliability by use of a pilot study with a small group of medical students and …

Lead Activation Of A Developmentally Regulated Calcium Channel In Rat Hippocampal Nerve Terminals, Troy E. Rhodes

Theses and Dissertations in Biomedical Sciences

Low level lead (Pb²⁺) exposure may produce lasting deficits in learning and memory by altering calcium (Ca²⁺) dependent processes. Isolated presynaptic nerve terminals from rat hippocampus were loaded with the intracellular (Ca²⁺) indicator Fura-2. The changes in cytoplasmic free calcium ([Ca²⁺]_i) were measured by stopped-flow fluorescence spectroscopy following depolarization with elevated potassium on a millisecond time scale (Lentzner et al., 1992). Depolarization promoted a rapid increase in Ca²⁺_i which occured in two kinetically distinguishable phases: a fast component, representing the activity of rapidly inactivating Ca²⁺ channels (τ …

Application Of Monoclonal Antibodies Against Creatine Kinase Mm And Bb Isoenzymes For Creatine Kinase Mb Isoenzyme Detection, Lei-Chieh Chuang

Chemistry & Biochemistry Theses & Dissertations

Nondiagnostic ECGs and unknown characteristic chest pains increase the diIIiculty of Acute Myocardial Infarction (AMI) diagnosis. Biochemical markers, such as creatine kinase MB isoenzymes (CK-MB) and myoglobin, are employed for the early detection of AMI. Compared to myoglobin, CK-MB reveals a higher specific indicator for AMI detection owing to its abundance in cardiac tissue. Hence, a successful CK-MB detection is expected to improve AMI diagnosis and therapy.

A CK-MB detecting ELISA system was set up based on a sandwich assay principle by using specific CK-B and CK-M monoclonal antibodies. The dimeric nature of the CK-MB isoenzyme provides two epitopes on …

Comparison Of Positive Screening And Confimatory Results From Federally Mandated Drug Testing Of Urine, Mary M. Stuck

Community & Environmental Health Theses & Dissertations

The purpose of this study was to analyze the accuracy of FDA approved immunoassays for the detection of drug positive urine samples.

Federal civilian employees are tested under the strict protocol of the Department of Health and Human Services mandatory guidelines for federal workplace drug testing programs. The guidelines provide for a two instrument testing protocol for the analysis of urine samples. The first is an FDA approved immunoassay. Samples which test positive on this screening immunoassay are then submitted for confirmatory testing with the "gold standard" gas chromatography/mass spectrometry.

Agency monthly drug testing summaries, required under the DHHS guidelines …

Neuronal Toxicity Of Humoral Factors From Patients With Diabetic Neuropathy And Mechanism Of Neuronal Death On Cultured Adrenergic Neurons: Studies Of Autoimmune Pathogenesis In Diabetic Neuropathy, Dong Liu

Theses and Dissertations in Biomedical Sciences

Diabetic neuropathy is an extremely common medical problem because of the high frequency of diabetes and its complications. Diabetic neuropathy consists of not one, but many patterns of nerve injury, each potentially with its own discrete pathogenic mechanisms. Evidence is accumulating that indicates autoimmunity plays a role in diabetic peripheral neuropathy. However, the significance of immunopathogenesis of diabetic neuropathy is as yet unclear.

Using the N1E-115 mouse neuroblastoma cell line (NB) as a model of the adrenergic autonomic neuron, we found that sera of IDDM patients with neuropathy inhibit growth and differentiation of adrenergic neurons in culture (Pittenger et al, …

A Computer-Simulated Restriction Fragment Length Polymorphism Analysis Of Bacterial Small-Subunit Rrna Genes: Efficacy Of Selected Tetrameric Restriction Enzymes For Studies Of Microbial Diversity In Nature, Craig L. Moyer, James M. Tiedje, Fred C. Dobbs, David M. Karl

OES Faculty Publications

An assessment of 10 tetrameric restriction enzymes (TREs) was conducted by using a computer-simulated restriction fragment length polymorphism (RFLP) analysis for over 100 proximally and distally related bacterial small-subunit (SSU) rRNA gene sequences. Screening SSU rDNA clone libraries with TREs has become an effective strategy because of logistic simplicity, commercial availability, and economy. However, the rationale for selecting the type and number of TREs has not been systematically evaluated. Our objective nas to identify the optimal combination of TREs for RnP screening of cloned SSU rRNA genes from undefined bacterial clone libraries. After computer-simulated TRE digestion, the resultant fragments were …

A Test Of An Alternate Calibration Matrix For Niosh Method 7300, Robert T. Vitek

Community & Environmental Health Theses & Dissertations

The purpose of this study was to determine if the analytical results (when determining cadmium, lead, and zinc concentrations) for air sample filters prepared and analyzed according to N:OSH Method 7300, differ significantly, from those obtained when the instrument is calibrated using EPA Method 200.7 acid matrix standards. The null hypothesis was that no statistically significant difference, measured at the 95% confidence level, would exist between results obtained from the two calibration standards. Careful standard and sample preparation, the use of an internal standard, and the application of working standard and working internal standard correction factors served to isolate the …

Seasonal And Mesoscale Variability In The Distribution Of Antarctic Krill, Euphausia Superba, West Of The Antarctic Peninsula, Cathy Meyer Lascara

OES Theses and Dissertations

Observations collected between November 1991 and September 1993 during four multidisciplinary cruises were analyzed to provide a description of seasonal and mesoscale variability in the distribution and abundance of Antarctic krill, Euphausia superba, within continental shelf waters west of the Antarctic Peninsula and to investigate possible relationships between variability in krill distributions and variability in selected environmental parameters. Acoustic measurements of krill were made each season at designated locations to estimate the abundance of krill, in terms of vertically-integrated krill biomass and the number of aggregations, characterize the depth distribution of krill, and provide a quantitative description of the size, …

Recruitment Of Blue Crab, Callinectes Sapidus, Postlarvae To The Back-Barrier Lagoons Of Virginia's Eastern Shore, Robert D. Brumbaugh

OES Theses and Dissertations

Most research on the early life history of the blue crab, Callinectes sapidus, has been conducted in large partially stratified estuaries such as the Chesapeake Bay. In contrast, little is known about the recruitment dynamics or habitat requirements of blue crab postlarvae (megalopae) in shallow well-mixed lagoonal systems that make up a considerable part of the species' range. In Virginia's coastal lagoons, planktonic blue crab megalopae are most abundant at night on flooding tides, and are not abundant during the daytime or on ebbing tides. This appears to enhance retention within the lagoons, despite the short residence time of water …

The Effects Of Environmental Variability On The Population Structure Of The Eastern Oyster (Crassostrea Virginica): A Modeling Study, Margaret Mcmanus Dekshenieks

OES Theses and Dissertations

Three models were coupled to investigate the effects of changes in environmental conditions on the population structure of the Eastern oyster, Crassostrea virginica. The first model, a time-dependent model of the oyster population as described in Powell et al. (1992) and Hofmann et al. (1992, 1995), tracks the distribution, development, spawning, and mortality of sessile oyster populations. The post-settlement model incorporates mortality through parasitism, predation, food depletion and extremes in environmental conditions. The post-settlement model supplies the initial abundance of larvae spawned into the water column, and in turn is the recipient of cohorts of spawn which survive through metamorphosis. …

Comparison Of Sapling Community Structure In Created And Natural Forested Wetlands In Southeastern Virginia, Sharon Ann Haines

Biological Sciences Theses & Dissertations

Forested wetlands are being destroyed at a rapid rate. Wetlands are valuable for flood control, aquifer recharge, and for their role in denitrification and storage of global carbon. When wetlands are lost, their functions and value to humans are lost as well. One response to the continued development of wetlands has been the artificial creation of new wetlands. This study compared the species density, relative density, coverage and frequency of occurrence of the woody vegetation in two southeastern Virginia created wetlands with that in two reference wetlands, also in southeastern Virginia, to determine the structural similarity of their respective communities. …

The Evaluation Of Succinylcholine Chloride For Harmful Effects Upon Early-Stage Mouse Embryos, Francis Warren Prescott

Biological Sciences Theses & Dissertations

Succinylcholine (SCh) chloride is a depolarizing neuromuscular blocking agent used to paralyze patients for surgical procedures. Over 1,800 clinical observations of newborn infants have demonstrated that succinylcholine does not cross the placenta in quantities detrimental to fetuses (Kolstad, et al., 1957, Bakhoum, et al., 1957, Hodges, et al., 1959, Duffield, et al., 1958, Dennis, et al., 1954, 1956, McNab, 1955, Coleman, et al., 1956, Lund, 1953). Later investigations which involved comparison of blood levels of SCh in the mother to those in fetuses bolstered the finding that SCh fails to cross the placenta in significant amounts (Moya and Kvisselgaard, 1961, …

Factors Affecting Nitrogen Fixation Rates In Termites (Isoptera: Rhinotermitidae: Reticulitermes) And Termite Nitrogen Contributions Of Forest Ecosystems, Anthony Duane Curtis

Biological Sciences Theses & Dissertations

Termites host symbiotic bacteria that fix atmospheric nitrogen, which makes termites important in the biogeochemical cycling of nitrogen in ecosystems. The objective of this study was to estimate annual nitrogen contributions by termites by examining seasonal rates of nitrogen fixation, seasonal abundance of different termite castes and their nitrogenase activity, the effects of dietary nitrogen on nitrogenase activity, and low oxygen and high carbon dioxide atmospheres on termite nitrogenase activity, and the accuracy of mark-recapture studies to estimate termite population size.

Termite nitrogen fixation rates were monitored monthly for 10 Reticulitermes Holmgren colonies from June, 1993, to December, 1995. Rates …

The Assessment Of Osteoinductivity Of Human Allograft Demineralized Bone Matrix By In Vivo And In Vitro Assay Models, Min Zhang

Theses and Dissertations in Biomedical Sciences

The osteoinductive potential (osteoinductivity) is a very important aspect of demineralized bone matrix (DBM) as a biomaterial. This study is directed at establishing qualitative and quantitative assays of the osteoinductivity of human DBM. Further aspects of this study include an assessment of the effects of the production process, matrix characterization, and donor related factors on osteoinductivity of the DBM.

Athymic mice were chosen as the animal model for use in the in vivo bioassay. Implantation of DBM in muscle pouches provided for much higher osteoinductivity (remineralization to 10% calcium) than subcutaneous site implantation (remineralization to 1.6% calcium). Histological observations revealed …

The Relationship Of Foot Types To Pressure Distribution Patterns Of The Forefoot During Gait, Hui-Ji Fan

Rehabilitation Sciences Theses & Dissertations

Pressure distribution under the foot has been considered a useful indicator in the treatment of foot problems. The purpose of this study was to determine the relationship between foot types and pressure patterns under the forefoot. Fifty-four healthy subjects (19 males, 35 females, mean age=27 years, S0=4, range=21-39) participated in this study. A BTE pedobarograph was used to record pressure distribution under the foot during barefoot walking. Foot types were classified as neutral, pronated, and supinated. Pressure distribution under the forefoot was classified as medial, central, and lateral patterns. The medial pattern had the highest peak pressure under the first …

An Enzyme-Linked Immunosorbent Assay For The Detection Of Cardiac Myoglobin Using Monoclonal Antibodies, Deborah F. Kelly

Chemistry & Biochemistry Theses & Dissertations

The most prevalent life-threatening disease worldwide, secondary to coronary artery thrombosis is Acute Myocardial Infarction (AMI). Increases in three clinical markers have been explored as an early means of AMI detection: Cardiac myoglobin, and the two specific cardiac isoforms of Creatine Kinase, CK-MM and CK-MB. However, myoglobin levels have shown to give a more accurate correlation (R = 0.89) than does Creatine Kinase evaluation. Therefore, we have developed a two-site Enzyme-Linked Immunosorbent Assay (ELISA) using monoclonal antibodies against myoglobin isolated from human heart tissue. This assay is based on specific anti-genantibody interactions and is sensitive at the nanogram level. We …

Toxin Producing Phytoplankton In Chesapeake Bay, Harold G. Marshall

Biological Sciences Faculty Publications

Three diatoms and nine dinoflagellates, known to be associated with toxin production, have been identified within Chesapeake Bay. Over the past several decades this number has increased to its present level so that they now represent approximately 1.7% the total number of phytoplankton species reported for the Bay.

Modulation Of Queuine Uptake And Incorporation Into Trna By Protein Kinase C And Protein Phosphatase, Rana C. Morris, Bonnie J. Brooks, K. Lenore Hart, Mark S. Elliot

Chemistry & Biochemistry Faculty Publications

It has been suggested that the rate of queuine uptake into cultured human fibroblasts is controlled by phosphorylation levels within the cell. We show that the uptake of queuine is stimulated by activators of protein kinase C (PKC) and inhibitors of protein phosphatase; while inhibitors of PKC, and down-regulation of PKC by chronic exposure to phorbol esters inhibit the uptake of queuine into cultured human fibroblasts. Activators of cAMP- and cGMP-dependent kinases exert no effect on the uptake of queuine into fibroblast cell cultures. These studies suggest that PKC directly supports the activity of the queuine uptake mechanism, and that …

Modeling The Vertical Distribution Of Oyster Larvae In Response To Environmental Conditions, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell

CCPO Publications

A size-structured, time and vertically-dependent model was used to investigate the effects of water column structure on the distribution of larvae of the oyster Crassostrea virginica. Formulations used to model larval growth and behavior are based upon laboratory studies. Simulated vertical larval distributions obtained for conditions representative of a well-mixed, partially stratified and strongly stratified water column illustrate the effect that salinity and temperature gradients have on moderating larval swimming and hence on larvae vertical location. For well-mixed conditions, smaller larvae are dispersed throughout most of the water column. For strongly stratified conditions, the smaller-sized larvae cluster within the …