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Articles 2671 - 2700 of 3343

Full-Text Articles in Life Sciences

Tissue-Specific Expression And Steroid Hormone Regulation Of Human Gonadotropin -Releasing Hormone (Hgnrh) Gene In Placental Cells (Jeg -3 Cells), Zhengguang Chen Jul 1999

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 May 1999

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 Comparison Of Gait Characteristics Between Older Adults Who Do Tai-Chi Chuan And Older Adults Who Do Not Do Tai-Chi Chuan, Shu-Ya Chen May 1999

The Comparison Of Gait Characteristics Between Older Adults Who Do Tai-Chi Chuan And Older Adults Who Do Not Do Tai-Chi Chuan, Shu-Ya Chen

Rehabilitation Sciences Theses & Dissertations

Tai-Chi Chuan (TCC) is a traditional Chinese exercise which has become popular in the Western world recently. The reported health benefits of TCC exercise include increased lower extremity muscle strength, improved balance, improved cardiopulmonary function, reduced tension, and improved overall wellness. However, no study has demonstrated the effects of TCC exercise on walking performance. The purpose of this study is to determine whether TCC exercise has an effect on normal speed walking of older adults. Twenty-four older healthy women over 55 were recruited in this study, 12 subjects practiced TCC exercise at least two times per week and the others …


The Accuracy Of Nitrous Oxide Passive Dosimeters As Compared With An Infra-Red Spectrographic Reference Method, Susan Allen May 1999

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.


Historical Relationships Of Atlantic Slope River Drainages, Eugene G. Maurakis, Diana L. Lipscomb Apr 1999

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 Apr 1999

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.


Benthic Community Analysis Of Hog Island Bay, Virginia, David James Lewis Apr 1999

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 …


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 Apr 1999

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 Apr 1999

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 …


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 Apr 1999

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

School of Medical Diagnostics & Translational Sciences 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 …


The Effect Of Illicit Drugs On The Cardiovascular And Hormonal Responses In Pregnant Rabbits, Andrea Alana Chambliss Apr 1999

The Effect Of Illicit Drugs On The Cardiovascular And Hormonal Responses In Pregnant Rabbits, Andrea Alana Chambliss

Biological Sciences Theses & Dissertations

The purpose of this study is to determine the effect of acute administration of heroin and ecgonine methyl ester (EME) on renin and atrial natriuretic peptide (ANP) secretion in time dated New Zealand White rabbits. Thirteen rabbits were studied. Arterial blood pressure and pCOz, increased significantly from a control value of 80 ± 8 mmHg and 30 ± 2 mmHg respectively to 93 ± 18 mmHg and 31 ± 1 mmHg. pO2 decreased from 99 ± 8 mmHg to 90 ± 11 mmHg 10 minutes after heroin administration. EME caused arterial blood pressure to significantly increase from a control …


Factors That Affect African-American Enrollment In Urban Agricultural Degree Programs In The Commonwealth Of Virginia, Thomas Earl Tracy Apr 1999

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 …


Production Of Copper-Complexing Ligands In Response To Elevated Concentrations Of Copper In Marine Synechococcus Spp., Arunsri Chatkaeomorakot Brown Apr 1999

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 …


Transcriptional Regulation Of The Bmp2 Gene: Retinoic Acid Induction In F9 Embryonal Carcinoma Cells And Saccharomyces Cerevisiae, Loree C. Heller, Yong Li, Kevin L. Abrams, Melissa B. Rogers Jan 1999

Transcriptional Regulation Of The Bmp2 Gene: Retinoic Acid Induction In F9 Embryonal Carcinoma Cells And Saccharomyces Cerevisiae, Loree C. Heller, Yong Li, Kevin L. Abrams, Melissa B. Rogers

Bioelectrics Publications

Bmp2, a highly conserved member of the transforming growth factor-beta gene family, is crucial for normal development. Retinoic acid, combined with cAMP analogs, sharply induces the Bmp2 mRNA during the differentiation of F9 embryonal carcinoma cells into parietal endoderm. Retinoic acid (RA) also induces the Bmp2 gene in chick limb buds. Since normal Bmp2 expression may require an endogenous retinoid signal and aberrant Bmp2 expression may cause some aspects of RA-induced teratogenesis, we studied the mechanism underlying the induction of Bmp2. Measurements of the Bmp2 mRNA half-life and nuclear run-on assays …


Trans-Resveratrol Inhibits Calcium Influx In Thrombin-Stimulated Human Platelets, Yuliya Dobrydneva, Roy L. Williams, Peter F. Blackmore Jan 1999

Trans-Resveratrol Inhibits Calcium Influx In Thrombin-Stimulated Human Platelets, Yuliya Dobrydneva, Roy L. Williams, Peter F. Blackmore

Chemistry & Biochemistry Faculty Publications

1 The phytoestrogenic compound trans-resveratrol (trans-3,5,4'-trihydroxystilbene) is found in appreciable quantities in grape skins and wine. It has been shown that both products rich in trans-resveratrol and pure trans-resveratrol inhibit platelet aggregation both in vivo and in vitro. However the mechanism of this action still remains unknown.

2 An essential component of the aggregation process in platelets is an increase in intracellular free Ca2+ ([Ca2+]i). Ca2+ must enter the cell from the external media through specific and tightly regulated Ca2+ channels in the plasma membrane. The objective …


Foreward, Virginia Journal Of Science Jan 1999

Foreward, Virginia Journal Of Science

Virginia Journal of Science

Foreward to the Winter 1999 issue of Virginia Journal of Science, discussing Pfiesteria Piscicida, written by Harold G. Marshall.


The Cause And Consequence Of Ontogenetic Changes In Social Aggregation In New Zealand Spiny Lobsters, Mark J. Butler Iv, Alistair B. Macdiarmid, John D. Booth Jan 1999

The Cause And Consequence Of Ontogenetic Changes In Social Aggregation In New Zealand Spiny Lobsters, Mark J. Butler Iv, Alistair B. Macdiarmid, John D. Booth

Biological Sciences Faculty Publications

Ontogenetic changes in the behavior, spatial distribution, or habitat use of a species are presumably adaptations to ecological forces that differ in their effect on various life stages. The New Zealand rock lobster Jasus edwardsii is one of several species of spiny lobster that exhibits dramatic ontogenetic shifts in sociality and spatial distribution, and we tested whether such changes are adaptive. We first surveyed several natural populations of J. edwardsii to document size-specific differences in aggregation. To determine if chemical cues discharged by conspecifics promote aggregation of certain ontogenetic stages, we tested the responsiveness of lobsters of 3 ontogenetic stages …


Nucleotide Sequence Of The Streptococcin A-Ff22 Lantibiotic Regulon: Model For Production Of The Lantibiotic Sa-Ff22 By Strains Of Streptococcus Pyogenes, Robert E. Mclaughlin, Joseph J. Ferretti, Wayne L. Hynes Jan 1999

Nucleotide Sequence Of The Streptococcin A-Ff22 Lantibiotic Regulon: Model For Production Of The Lantibiotic Sa-Ff22 By Strains Of Streptococcus Pyogenes, Robert E. Mclaughlin, Joseph J. Ferretti, Wayne L. Hynes

Biological Sciences Faculty Publications

Streptococcin A-FF22 (SA-FF22) is a type AII linear lantibiotic produced by Streptococcus pyogenes strain FF22. Sequence analysis of an approximate 10 kb region of DNA showed it to contain nine open reading frames arranged in three operons responsible for regulation, biosynthesis and immunity of SA-FF22. This region is organized similarly to the Lactococcus lactis lacticin 481 region, however, unlike lacticin 481, a two-component regulatory system is essential for SA-FF22 production. located immediately downstream of the scn region is a putative transposase gene, the presence of which supports earlier data that indicated a mobile nature to this region. (©) 1999 Published …


Nuclear Receptor Co-Repressor Gene Localizes To 17p11.2, A Frequently Deleted Band In Malignant Disorders, Michael W. Stacey, Jianxiang Wang, Rebecca L. Byrd, Johnson M. Liu, William G. Kearns Jan 1999

Nuclear Receptor Co-Repressor Gene Localizes To 17p11.2, A Frequently Deleted Band In Malignant Disorders, Michael W. Stacey, Jianxiang Wang, Rebecca L. Byrd, Johnson M. Liu, William G. Kearns

Bioelectrics Publications

The t(8;21) between the AML1 and ETO genes is a commonly seen genetic alteration in acute myeloid leukemia. Recently, we reported that the fusion partner ETO binds to the human nuclear receptor co-repressor (NCOR), a member of the NCOR/SIN3/histone deacetylase complex. This complex mediates transcriptional repression as a result of chromatin remodeling. Here, we used a combination of fluorescence in situ hybridization and hybrid panels to localize the human NCOR gene (NCOR) to chromosome band 17p11.2. The position of human NCOR on 17p11 raises the possibility of deranged transcriptional regulation in malignant disorders associated with deletions of 17p.


Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. I. Model Development, Implementation, And Verification, Susan Ford, Eric Powell, John Klinck, Eileen Hofmann Jan 1999

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 …


Field Sampling And Necropsy Examination Of Fish, A. S. Kane, A. Baya, R. Reimschuessel, K. M. St. Pé, C. A. Poukish, C. P. Driscoll Jan 1999

Field Sampling And Necropsy Examination Of Fish, A. S. Kane, A. Baya, R. Reimschuessel, K. M. St. Pé, C. A. Poukish, C. P. Driscoll

Virginia Journal of Science

This paper presents an overview of observational and fish sampling tech­niques for investigating fish lesions, morbidity and mortality. These sam­pling techniques and investigations are much like detective work and require attention to detail, common sense, technical proficiency and experience. To solve the mystery of a fish kill, the investigator must use available evidence and clues to piece together a series of events that often have long since passed. The cause of these field events may be chemical, biological or physical; more often, it is some combination of these. An initial categorization approach may be used to reduce the great number …


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 Jan 1999

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.


Virginia's Pfiesteria Monitoring Program: Water Quality, Roger K. Everton, Wick T. Harlan, Jonathan W. Priest, Mark S. Alling Jan 1999

Virginia's Pfiesteria Monitoring Program: Water Quality, Roger K. Everton, Wick T. Harlan, Jonathan W. Priest, Mark S. Alling

Virginia Journal of Science

During the summer and early fall of 1998, 34 estuarine stations in Virginia were sampled for Pfiesteria like organisms (PLOs) and associated water quality conditions. Stations were sampled either bimonthly (20 stations) or monthly (14 stations) from June to October 1998. At each station, a set of live and Lugol' s preserved samples were collected for presumptive counts of PLOs and water quality conditions were determined. Water quality parame­ters measured included standard field parameters, nutrients (total, dissolved, and particulate), chlorophyll a, and conventional water quality indicators. Although PLOs were relatively low in 1998 as compared to 1997, presump­tive PLO counts …


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 Jan 1999

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 Jan 1999

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 …


Growth And Feeding Studies On The Algal Feeding Stage Of A Pfiesteria-Like Dinoflagellate, David W. Seaborn, A. Michelle Seaborn, William M. Dunstan, Harold G. Marshall Jan 1999

Growth And Feeding Studies On The Algal Feeding Stage Of A Pfiesteria-Like Dinoflagellate, David W. Seaborn, A. Michelle Seaborn, William M. Dunstan, Harold G. Marshall

Virginia Journal of Science

The dinoflagellate Cryptoperidiniopsis sp. was isolated from sediment samples taken from Virginia estuaries, and established in culture for subsequent growth and feeding studies. The maximum abundance, or yield, of Cryptoperidiniopsis is exponentially related to the concentration of algal prey and is saturated at about 4.00 X 105 mL-1. Salinity from 10-20 ppt and temperature between 15-25 C have no effect on the yield of this form of Cryptoperidiniopsis. Light intensity has a secondary effect in that the algal prey reproduces more quickly in higher light as they are being grazed. Growth rates of Cryptoperidiniopsis were …


Water Quality Relationships To Concentrations Of Pfiesteria-Like Organisms In Virginia Estuaries For 1998, Everett P. Weber, Harold G. Marshall Jan 1999

Water Quality Relationships To Concentrations Of Pfiesteria-Like Organisms In Virginia Estuaries For 1998, Everett P. Weber, Harold G. Marshall

Virginia Journal of Science

A series of statistical analyses were performed to identify the relationship between abundance of dinoflagellates grouped as Pfiesteria-like organisms and a set of 25 water quality variables from May through October of 1998 at 41 estuarine locations. Although regions were identified in relation to seasonal density of cells present, there were no strong relationships to specific water quality variables. Factors that may have influenced these results included: a) several species were included in the group analyzed and this composite did not respond as a unit to changing environmental conditions; b) cell concentrations were low and there were a large …


Construction Of An Escherichia Coli Lac Repressor-Based System To Study Human Cytomegalovirus Gene Expression, Laura Fernanda Cageao-Luchetti Jan 1999

Construction Of An Escherichia Coli Lac Repressor-Based System To Study Human Cytomegalovirus Gene Expression, Laura Fernanda Cageao-Luchetti

Theses and Dissertations in Biomedical Sciences

An Escherichia coli lac repressor-based system was developed to study the roles of human cytomegalovirus (HCMV) genes during viral replication. To this end, a recombinant HCMV expressing the lac repressor was generated (RVlac), and an HCMV-specific promoter was targeted for conditional expression by inserting the lac operator sequence. The promoter of a nonessential gene was chosen in order to be able to assess parameters of repression and derepression of the operator-containing promoter in the endogenous locus, without having virus growth dependent on the specific inducer isopropylthiogalactoside (IPTG). The feasibility of this approach to conditionally express an HCMV promoter …


Growth And Feeding Studies On The Algal Feeding Stage Of A Pfiesteria-Like Dinoflagellate, David W. Seaborn, A. Michelle Seaborn, William M. Dunstan, Harold G. Marshall Jan 1999

Growth And Feeding Studies On The Algal Feeding Stage Of A Pfiesteria-Like Dinoflagellate, David W. Seaborn, A. Michelle Seaborn, William M. Dunstan, Harold G. Marshall

Biological Sciences Faculty Publications

The dinoflagellate Cryptoperidiniopsis sp. was isolated from sediment samples taken from Virginia estuaries, and established in culture for subsequent growth and feeding studies. The maximum abundance, or yield, of Cryptoperidiniopsis is exponentially related to the concentration of algal prey and is saturated at about 4.00 X 105 mL-1. Salinity from 10-20 ppt and temperature between 15-25 C have no effect on the yield of this form of Cryptoperidiniopsis. Light intensity has a secondary effect in that the algal prey reproduces more quickly in higher light as they are being grazed. Growth rates of Cryptoperidiniopsis were …


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 Jan 1999

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 …