Life Sciences Commons^™

Comparative Taphonomy And Paleoecology Of A Glaciomarine Fauna, Carboniferous (Westphalian- Namurian) La Capilla Fm., Argentina, Rex A. Hanger, Mohutsiwa Gabadirwe

Virginia Journal of Science

The Carboniferous La Capilla Fm. of the Calingasta-Uspallata basin of western Argentina contains a low diversity fauna inhabiting a continental shelf under glacial ice fronts advancing from the east. Distal glaciomarine sediments on these ice-influenced shelves of Gondwana are most commonly interpreted as being deposited under quiet, low-energy conditions. Ta­phonomic and paleoecologic analysis of a sample of the fauna reveals the following: low species richness, yet comparable equitability to coeval, tropi­cal faunas; low articulation ratios and high pedicle valve dominance for brachiopods; diverse corrasion modes, about half relatively high categories; one hundred percent fracturing of brachiopod shells, with carinate fracture …

Three-Dimensional Reconstructions Of Tadpole Chondrocrania From Historical Sections, Gary Radice, Mary K. Boggiano, Mark Desantis, Peter Larson, Joseph Oppong, Matthew Smetanick, Todd Stevens, James Tripp, Rebecca Weber, Michael Kerckhove, Rafael De Sá

Virginia Journal of Science

Reconstructing three dimensional structures (3DR) from histological sections has always been difficult but is becoming more accessible with the assistance of digital imaging. We sought to assemble a low cost system using readily available hardware and software to generate 3DR for a study of tadpole chondrocrania. We found that a combination of RGB can1era, stereomicro­scope, and Apple Macintosh PowerPC computers running NIH Image, Object Image, Rotater, and SURFdriver software provided acceptable reconstruc­tions. These are limited in quality primarily by the distortions arising from histological protocols rather than hardware or software.

Cartilage Regeneration On A Large Articular Surface Facilitated By Stress Shielding, Charles L. Mcdowell, Jennifer S. Wayne, Robert Tuten, Hunter H. Mcguire Jr.

Virginia Journal of Science

An animal model for the study of articular cartilage regeneration in-vivo facilitated by stress-shielding is introduced. The object of the model is to test the hypothesis that some form of cartilaginous tissue will grow upon a large joint surface in vivo with the joint in normal motion. The model utilizes the known capability of immature cells to differentiate. The source of cells is bleeding subchondral bone. In addition, the model provides a mechanically shielded environment in which cell differentiation and maturation can occur. The study showed that a substantial amount of tissue will grow in the animal model only when …

A Study On The Effects Of The N-Terminal Amino Acid Sequence On The Activation Of Human T-Cell Leukemia Virus Type 1 Protease, Hidayah Muhammad Kendall

Chemistry & Biochemistry Theses & Dissertations

Human T-cell leukemia virus type 1 (HTL V-1) is dependent upon the enzymatic activity of its protease for maturation. Maturation of the protease is facilitated by cleavage of specific amino acid residues, followed by dimerization. The effects of the amino acid sequence located N-terminally to the cleavage site on the ability of the protease to become active were the focus of the current study. These amino acid sequences were contributed by the plasmid vector into which the protease gene was inserted.

Surface probability analyses (SPAs) of the vectors, as well as for native sequences which produce the mature protease and …

Pfiesteria Piscicida And Dinoflagellates Similar To Pfiesteria, Harold G. Marshall

Virginia Journal of Science

Pfiesteria pisiccida is a microscopic, unicellular organism that is classified as both a mixotrophic and heterotrophic dinoflagellate, which has been associated with both fish deaths and a cause of human illness (Burkholder et al., 1992; Glasgow et al., 1995; Burkholder and Glasgow, 1997). This species possesses a complex life cycle that includes motile forms (e.g. zoospores, gametes, amoebae) and a cyst stage that may remain dormant in the sediment (Burkholder et al., 1995b). Pfiesteria piscicida is known to have toxin and non-toxin producing populations, where cyst transformation into the toxic motile zoospores may be initiated by the presence of certain …

The Impact Of Resident And Transient Predators On The Popultation Dynamics Of Juvenile Caribbean Spiny Lobster (Panulirus Argus) In Florida Bay, Florida, Jason Edward Schratwieser

Biological Sciences Theses & Dissertations

There has been a considerable amount of research devoted to exploring the relationship between predators and prey, but many of these studies fail to address how predation can vary over spatial and temporal scales. The tendency of ecologists to model predation as a static entity often masks its capacity for creating distinctive effects in prey populations and communities. Most predation studies also focus on the effect of a single species of predator on a prey population, an unrealistic situation in nature. In the Florida Keys, juvenile spiny lobsters are subjected to two general classes of predators: i) "resident" predators such …

Use Of Extractable Lipofuscin For Age Determination Of Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey

OES Faculty Publications

The blue crab Callinectes sapidus is an economically and ecologically important species in many temperate estuaries, yet stock assessments have been limited to length-based methods for demographic analyses. We evaluated the potential of age pigments (lipofuscins) sequestered in neural tissue of eye-stalks and brains to estimate the age of blue crabs collected from Chesapeake Bay and Chincoteague Bay. The rate of lipofuscin accumulation was determined using crabs of known age reared in the laboratory. Age pigments were extracted from neural tissues (eye-stalk or brain), quantified, and normalized to protein content to allow comparisons across tissue types and crab sizes. Field-collected …

Identification And Characterization Of Determinants Of Head And Neck Tumor Cell Invasion, Yangguan Wu

Theses and Dissertations in Biomedical Sciences

Head and neck squamous cell carcinoma (HNSCC) is a common malignant disease with poor prognosis. The majority of patients die from local invasion or lymphatic metastasis. The mechanism(s) underlining the invasiveness of HNSCC are poorly understood. Utilizing a panel of HNSCC cell lines previously established in our laboratory, we tested the application and relevance of the three-step hypothesis of tumor invasion to HNSCC and investigated the mechanism(s) pertaining to the regulation of each step in the invasive process. Data presented in this thesis demonstrated that tumor cell invasion in HNSCC is a complex process involving three repeated sequential steps: adhesion, …

Generation Of Human Chorionic Gonadotropin Beta Subunit Specific Monoclonal Antibody Using A Synthetic Peptide, Zhe Huang

Chemistry & Biochemistry Theses & Dissertations

Human chorionic gonadotropin (hCG) is well known for early immunological and bioassay tests for early detection of pregnancy. Since the hormone specific beta subunit confers unique biological and immunological specificity to hCG, immunochemical measurement of hCG has achieved greater specificity and sensitivity in recent years by using either the beta subunit as an immunogen or a partially reduced beta subunit polypeptide chain. However, antiserum raised against the entire hCG beta subunit usually cross-reacts to some extent with human luteinizing hormone (hLH). hCG has been found to be present in the extract of tumors and minute quantities of hCG are synthesized …

Encystment, Excystment And Photosynthetic Activity In The Temporary Cysts Of Amphidinium Carterae, Steven R. Kibler

OES Theses and Dissertations

Although the formation of temporary cysts has been documented in several papers, the physiology of these stages has remained obscure. Research dealing with dinoflagellate resting stages has primarily targeted sexual cysts. Accordingly, formation, germination and photosynthetic activity in the temporary cysts of Amphidinium carterae have been investigated in the present study. The effect of light intensity upon cyst germination was tested by incubating temporary cysts at three different light intensities. In order to assess the potential for photosynthesis in cysts, cellular chlorophyll-a concentrations and cellular fluorescence were quantified during encystment. Photosynthetic carbon uptake of H¹⁴CO₃^- was …

Exploring Participation Processes For Technology Development: Case Studies Of Biotechnology Research And Development Projects In Thailand, Omjai Yuktavetya

Engineering Management & Systems Engineering Theses & Dissertations

There is increased awareness in the organizational and management literature that participation can make contributions in technology development. One of the problems in developing biotechnology in Thailand is that only a small portion of publicly funded research and development projects directly result in commercial success. Among the reasons cited (TDRI 1992a) is a lack of collaboration between various stakeholders; therefore, an effective technology policy to support their participation is needed. This research explores current participation processes in biotechnology research and development projects in Thailand in which there were different perspectives among various stakeholders. The quantitative and qualitative methodologies developed here …

An Extracellular Protein Produced By Staphylococcus Hominis Strain Αm With Antimicrobial Activity Against Mycobacterium Spp, Sandra May Jacobsen

Biological Sciences Theses & Dissertations

The inhibitory activity exhibited by Staphylococcus hominis strain αM toward Mycobacterium species was examined. These studies included determining the conditions that maximized inhibitory agent production, analyzing characteristics of the agent, determining the time of agent production, ascertaining plasmid possession and the role of plasmids in the production of this inhibitory agent, and ascertaining the antimicrobial activity of other strains of S. hominis. On solid and in liquid media, S. hominis strain αM exhibits a unique inhibitory activity toward Mycobacterium species that is not demonstrated by Staphylococcus epidermidis or other S. hominis strains. Maximum agent production and recovery was …

Nitrate Reductase Activity, Nitrate Uptake And Iodine Speciation In The Marine Environment, Chin-Chang Hung

OES Theses and Dissertations

The present method for the determination of new production (NP) by measuring the uptake of added ¹⁵NO₃^– suffers from a number of limitations. In an attempt to improve this situation, this research examined the possibility of estimating ¹⁵NO₃– uptake by measuring the activity of nitrate reductase (NRA). In addition, because it has long been suspected that the biological reduction of IO₃^– to I^– may be mediated by nitrate reductase (NR), this research investigated the ability of NR to catalyze the reduction of iodate to iodide.

An improved method for the determination …

Tissue-Specific Expression And Steroid Hormone Regulation Of Human Gonadotropin -Releasing Hormone (Hgnrh) Gene In Placental Cells (Jeg -3 Cells), Zhengguang Chen

Theses and Dissertations in Biomedical Sciences

Using JEG-3 cells as an in vitro model, I investigated the mechanisms behind the tissue-specific expression and steroid hormone regulation of the hGnRH gene in the human placenta. The hGnRH upstream promoter was found to be functionally active in JEG-3 cells. The DNA sequence responsible for functioning of the upstream promoter in JEG-3 cells is narrowed to a region between –1048 bp and –730 bp. This DNA fragment contains four elements, which can bind with nuclear extract from JEG-3 cells (but not from GT1-7 cells).

Estradiol (E2) represses the hGnRH upstream promoter activity in JEG-3 cells. This inhibition is receptor-mediated, …

Adaptive Strategies That Reduce Predation On Caribbean Spiny Lobster Postlarvae During Onshore Transport, Charles A. Acosta, Mark J. Butler Iv

Biological Sciences Faculty Publications

Like many marine species with meroplanktonic larvae, the Caribbean spiny lobster (Panulirus argus) has a postlarval stage that moves from the oceanic plankton to inshore nurseries only under specific environmental conditions (i.e., at night, in the surface water layer, on the flood tide, and during new moon), presumably to avoid predation or to enhance onshore transport. Using held and mesocosm experiments, we compared predation on planktonic postlarvae swimming at night near the surface and bottom over coastal habitats along typical offshore-inshore transport paths and determined whether predation rates differed between lunar periods (new moon vs, full moon) and with prey …

The Accuracy Of Nitrous Oxide Passive Dosimeters As Compared With An Infra-Red Spectrographic Reference Method, Susan Allen

Community & Environmental Health Theses & Dissertations

Nitrous oxide is a gas often used in dental, surgical and veterinary operations as an anesthetic agent. Employees stationed in proximity of fugitive gas emissions may potentially suffer adverse health effects from chronic exposure to this agent. Passive dosimeters can be worn in the breathing zone of potentially affected personnel during exposure periods, then later analyzed to quantify nitrous oxide exposure. This study sought to establish the accuracy of several commercially available passive monitoring devices for nitrous oxide by comparison against an infra-red spectrophotometric reference method.

Conservation Status Of The Southern Appalachian Herpetofauna, Joseph C. Mitchell, Thomas K. Pauley, David I. Withers, Steven M. Roble, Brian T. Miller, Alvin L. Braswell, Paul V. Cupp Jr., Christopher S. Hobson

Virginia Journal of Science

Seventy one species of amphibians (55 salamanders, 16 anurans) and 46 species of reptiles (15 turtles, 8 lizards, 23 snakes) inhabit a five state area (Kentucky, North Carolina, Tennessee, Virginia, West Virginia) in the southern Appalachian region bordered by the Potomac River, the Blue Ridge Mountains, and the western margin of the Appalachian Plateau. Of these, 47.9 % of the amphibian fauna and 52.2 % of the reptilian fauna are listed as being of conservation concern by federal, state, and Natural Heritage programs in all or a portion of their ranges of this region. The Shenandoah salamander (Plethodon Shenandoah …

Characterization And Identification Of A Sludge-Associated Bacterial Isolate, Abiodun O. Adibi, Derrell Mcpherson, Minna Laine

Virginia Journal of Science

During a metal speciation study, an unusually high retention of lead ·was observed when lead solution was percolated through a column packed with sludge compost obtained from Hampton Roads Sanitation department. A bacterium was isolated from the sludge compost and identified as Bacillus sphaericus using electron microscopy, whole cell fatty acid analysis (Midi System) and Biolog GP Microplate. The isolate grows in broth and agar media containing up to 800 µM lead. Lead accumulation study using atomic absorption spectrophotometer indicates that the isolate adsorbs lead. Lead adsorption is pH dependent. The isolate contains a plasmid of approximately 40 -50 kbp …

Historical Relationships Of Atlantic Slope River Drainages, Eugene G. Maurakis, Diana L. Lipscomb

Virginia Journal of Science

An analysis of the historical relationships of 19 river drainages (St. Lawrence to Altamaha) on the Atlantic slope of the Appalachian Mountains was conducted using the shared presence of 124 native species of cyprinid fishes. This analysis resulted in an area cladogram that suggests that the rivers of the southern Atlantic slope were historically connected to the drainage of three southern rivers (Flint, Chattahoochee, and Apalachicola) which drain into the Gulf of Mexico. The mid Atlantic and northern Atlantic slope rivers appear to be historically related in support of earlier hypotheses that the mid Atlantic region provided a refugium for …

Possible Predation Scars On Rectithyris Subdepressa (Stoliczka, 1872), Late Cretaceous (Maastrichtian) Kallankurichi Fm., India, Rex Alan Hanger, Rama Krishnaswamy

Virginia Journal of Science

A single specimen of the terebratulid brachiopod, Rectithyris subdepressa (Stoliczka, 1872) from the Late Cretaceous (Maastrichtian) Kallankurichi Fonnation of southern India was found with durophagous predation traces. This occurrence is significant as it is possibly the first documentation of elasmobranch shark predation on brachiopods from the Mesozoic.

Insulinlike Growth Factor 1- And 2-Augmented Collagen Gel Repair Of Facial Osseous Defects, James S. Toung, Roy C. Ogle, Raymond F. Morgan, William H. Lindsey

Medical Diagnostics & Translational Sciences Faculty Publications

BACKGROUND: Defects of the facial bone structure are common problems for the facial plastic surgeon. Native type 1 collagen gels (T1CGs) have been shown to mediate repair of facial critical-size defects in rat models.

OBJECTIVE: To evaluate the efficacy of T1CG augmented with insulinlike growth factor (IGF) 1, IGF-2, and a combination of IGF-1 and IGF-2 on the repair of facial critical-size defects in a rodent model.

METHODS: Twenty-four retired male breeder Sprague-Dawley rats were divided into 4 groups of 6 animals. Facial critical-size defects were created by removing the nasalis bones with a bone-cutting drill. Defects were treated with …

Production Of Copper-Complexing Ligands In Response To Elevated Concentrations Of Copper In Marine Synechococcus Spp., Arunsri Chatkaeomorakot Brown

Theses and Dissertations in Biomedical Sciences

Synechococcus spp. (marine cyanobacteria) are extremely sensitive to copper toxicity and can produce high-affinity ligands of unknown structure which form complexes with free cupric ion. These ligands may contribute to the biological control of the levels of free cupric ions in surface seawater. Synechococcus spp. are known to produce metallothioneins (MT) in response to cadmium and zinc stress. In the present study the hypothesis that marine Synechococcus produce MT in response to copper was tested. Three marine Synechococcus spp. i.e., PCC 7001, PCC 73109, and PCC 7003, were exposed to different concentrations of CUSO 4 for various time periods. Size …

Factors That Affect African-American Enrollment In Urban Agricultural Degree Programs In The Commonwealth Of Virginia, Thomas Earl Tracy

Theses and Dissertations in Urban Services - Urban Education

The purpose of this study was to determine reasons why few African Americans are in leadership positions in the urban agriculture industry. The lack of leaders will probably continue because there is a dearth of African Americans enrolled in agriculture programs at colleges and universities in the Commonwealth of Virginia.

Six research questions guided the study in its endeavor to determine perceptions about the urban agriculture industry. Data were collected through surveys and interviews. A background questionnaire, developed by the researcher collected data on age, academic interests, urban background, exposure to agriculture occupations, and factors that affected selection of college …

Benthic Community Analysis Of Hog Island Bay, Virginia, David James Lewis

Biological Sciences Theses & Dissertations

The benthic infaunal macroinvertebrate communities of Hog Island Bay of the Virginia Eastern Shore were quantitatively sampled at 30 locations on August 31 and September 1, 1995. The primary objectives of this study were: (1) to characterize the subtidal macroinfaunal benthic communities of Hog Island Bay, (2) to examine relationships between abiotic factors and the macroinfaunal communities and (3) to characterize the environmental condition of the system using the Benthic Index of Biotic Integrity (B-IBI) (Weisburg et al. 1997) and the EMAP Benthic Index for the Virginian Province (Strobel et al. 1995).

The ecological condition of Hog Island Bay appears …

Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. Ii. Salinity Effects, Michelle C. Paraso, Susan E. Ford, Eric N. Powell, Eileen E. Hofmann, John M. Klinck

CCPO Publications

An oyster population model coupled with a model for Haplosporidium nelsoni, the causative agent of the oyster disease MSX, was used with salinity time-series constructed from Delaware River flow measurements to study environmentally-induced variations in the annual cycle of this disease in Delaware Bay oyster populations. Model simulations for the lower Bay (high salinity) sire reproduced the annual cycle observed in lower Delaware Bay. Simulations at both upper Bay (low salinity) and lower Bay sites produced prevalences and intensities that were consistent with field observations. At all sites, low freshwater discharge resulted in increased disease levels, whereas high freshwater …

Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. I. Model Development, Implementation, And Verification, Susan Ford, Eric Powell, John Klinck, Eileen Hofmann

CCPO Publications

A mathematical model simulating the host-parasite-environmental interactions of eastern oysters (Crassostrea virginica) and the pathogen, Haplosporidium nelsoni, which causes MSX disease, has been developed. The model has 2 components. One replicates the infection process within the oyster and the other simulates transmission. The infection-development component relies on basic physiological processes of both host and parasite, modified by the environment, to reproduce the observed annual prevalence cycle of H. nelsoni. Equations describing these rates were constructed using data from long-term field observations, and field and laboratory experiments. In the model, salinity and temperature have direct effects upon …

Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. Iii. Regional Application And The Problem Of Transmission, Eric N. Powell, John M. Klinck, Susan E. Ford, Eileen E. Hofmann, Stephen J. Jordon

CCPO Publications

A model of transmission for Haplosporidium nelsoni, the disease agent for MSX disease, is developed and applied to sites in Delaware Bay and Chesapeake Bay. The environmental factors that force the oyster population- H. nelsoni model are salinity, temperature, food, and total suspended solids. The simulated development of MSX disease was verified using 3 time series of disease prevalence and intensity: 1960 to 1970 and 1980 to 1990 for Delaware Bay, and 1980 to 1994 for Chesapeake Bay, and for a series of sites covering the salinity gradient in each bay. Additional simulations consider the implications of assumptions made …

Pcr And Fish Detection Extends The Range Of Pfiesteria Piscicida In Estuarine Waters, P. A. Rublee, J. Kempton, E. Schaefer, J.M. Burkholder, H. B. Glasgow Jr., David Oldach

Virginia Journal of Science

PCR and fluorescent in situ hybridization probes were used to assay for the presence of the dinoflagellate Pfiesteria piscicida in 170 estuarine water samples collected from New York to northern Florida. 20% of samples tested positive for the presence of P. piscicida, including sites where fish kills due to Pfiesteria have occurred and sites where there was no historical evidence of such events. The results extend the known range of P. piscicida northward to Long Island, New York. The results also suggest that P. piscicida is common, and normally benign, inhabitatant of estuarine waters of the eastern US.

A Cohort Study To Determine The Epidemiology Of Estuary-Associated Syndrome, Elizabeth Turf, Lily Ingsrisawang, Megan Turf, J.D. Ball, Michael Stutts, John Taylor, Suzanne Jenkins

Virginia Journal of Science

From the Introduction:

Estuary-Associated Syndrome (EAS) is the name given to a potential illness characterized primarily by changes in an individual's cognitive abilities, including acute onset of memory loss or the sudden inability to solve simple problems. Other possible signs of illness include respiratory symptoms, skin rash, or gastrointestinal distress. This illness appears to arise following exposure to toxin produced by Pfiesteria piscicida, or other toxic dinoflagellates, that resides in estuary waters.

….

In order to learn more about this possible syndrome and to determine if a causal relationship exists between association to waters containing Pfiesteria or other toxic …

Monitoring Results For Pfiesteria Piscidida And Pfiesteria-Like Organisms From Virginia Waters In 1998, Harold G. Marshall, David W. Seaborn, Jennifer Wolny

Virginia Journal of Science

Results of an extensive 1998 monitoring program for the presence of Pfiesteria-like organisms (PLO) in Virginia estuaries indicate these dinoflagellates are widely distributed in both the water column, and as cysts in the sediment, however Pfiesteria piscicida was not detected at this time. The highest concentrations of PLO were in estuaries along the Virginia shore line of the Potomac River, and in western Chesapeake Bay estuaries from the Little Wicomico River to the Rappahannock River. The most common PLO included Cryptoperidiniopsis sp. and Gymnodinium galatheanum. The lowest PLO concentrations were at ocean side locations. PLO were also …