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Articles 2521 - 2550 of 3346

Full-Text Articles in Life Sciences

Determination Of Nuclear Factor-Kappa B Activation In Cultured Renal Epithelial Cells And Cardiac Myocytes Exposed To Cocaine And Morphine, David Angeles Tiangco Apr 2002

Determination Of Nuclear Factor-Kappa B Activation In Cultured Renal Epithelial Cells And Cardiac Myocytes Exposed To Cocaine And Morphine, David Angeles Tiangco

Biological Sciences Theses & Dissertations

Nuclear factor-kappa B (NF-kB) is an important transcription factor that participates in the genetic regulation of inflammation in many tissues. Cocaine and heroin are drugs of abuse associated with renal and cardiac pathology. The purpose of this study was to test the hypothesis that exposure to cocaine or morphine (a metabolite of heroin) would activate NF-kB in renal epithelial cells (COS-7) and cardiac myocytes (H9c2) grown in culture. COS-7 and H9c2 cells were co-transfected with an experimental reporter specific for NF-kB activation and a control reporter with constitutive activity. A dual-luciferase assay was used to determine levels of NF-kB activation …


Prostate Specific Membrane Antigen (Psma): Immunoassay Development And Characterization Of Transcriptional Regulation, Zhen Xiao Apr 2002

Prostate Specific Membrane Antigen (Psma): Immunoassay Development And Characterization Of Transcriptional Regulation, Zhen Xiao

Theses and Dissertations in Biomedical Sciences

Prostate cancer (PCA) is the most common cancer and the second leading cause of death among American men. The high mortality is greatly attributed to the lack of early detection tools and effective treatment for metastasis and relapses. Biomarkers that can discriminate benign from malignant tumor and signal the development of androgen independent and metastatic tumor are needed. A biomarker designated prostate specific membrane antigen (PSMA) has the potential to fulfill this need. The objective of this study is to develop a clinically useful immunoassay for quantitation of serum PSMA and to study the molecular mechanism underlying the upregulation of …


A Baseline Assessment Of Furbearers On The Upper Coastal Plain Of Virginia, A. Scott Bellows, Joseph C. Mitchell Jan 2002

A Baseline Assessment Of Furbearers On The Upper Coastal Plain Of Virginia, A. Scott Bellows, Joseph C. Mitchell

Virginia Journal of Science

We assessed the status of furbearing mammals on Fort A.P. Hill, Caroline County, Virginia during the 1998-1999 trapping season with the cooperation of local licensed trappers. Our analyses were based on 345 captures representing of 10 mammal species, ranging from one bobcat (Lynx rufus) to 157 beavers (Castor canadensis). Mean number of captures per 100 trap nights was 17.0. Captures varied from 11.9 to 17.9 per 100 trap nights for conibear traps and 9.7 to 18.3 per 100 trap nights for leg-hold traps. External measurements of six species were similar to those reported for other populations …


Environmental Factors Contributing To The Disaggregation Of A Colonial Cyanoprokaryote And Its Influence On Picoplankton Abundance Within Lake Joyce, Virginia, Lewis F. Affronti Jr., B. Thomas Duquette Jan 2002

Environmental Factors Contributing To The Disaggregation Of A Colonial Cyanoprokaryote And Its Influence On Picoplankton Abundance Within Lake Joyce, Virginia, Lewis F. Affronti Jr., B. Thomas Duquette

Virginia Journal of Science

A colonial cyanoprokaryote, Aphanocapsa holsatica and autotrophic picoplankton abundance were monitored weekly over a two year period in Lake Joyce, Virginia. Significant differences were observed in both the cyanoprokaryote and picoplankton abundance over the study period and an inverse relationship was observed between these two plankton groups. Disaggregation of colonies was shown to contribute to picoplankton populations where water temperature and precipitation input apparently trigger colony dispersion. This relationship is suggested to occur in other aquatic habitats. Results of this work and its implications for ecosystem dynamics are discussed.


Vo2 Reserve And The Minimal Intensity For Improving Cardiorespiratory Fitness, David P. Swain, Barry A. Franklin Jan 2002

Vo2 Reserve And The Minimal Intensity For Improving Cardiorespiratory Fitness, David P. Swain, Barry A. Franklin

Human Movement Studies & Special Education Faculty Publications

Purpose: The American College of Sports Medicine has stated that aerobic: training needs to occur at a minimum threshold intensity of 50% VO2max for most healthy adults and at 40% VO2max for those with a very low initial fitness. Recently, the concept of VO2 reserve (% VO2R, i.e., a percentage of the difference between maximum and resting VO2 has been introduced for prescribing exercise intensity, This analysis was designed to determine the threshold intensity for improving cardiorespiratory fitness expressed as %VO2R units. Methods: Previous studies in healthy subjects (N = 18) that …


Il-12 Plasmid Delivery By In Vivo Electroporation For The Successful Treatment Of Established Subcutaneous B16.F10 Melanoma, M. Lee Lucus, Loree Heller, Domenico Coppola, Richard Heller Jan 2002

Il-12 Plasmid Delivery By In Vivo Electroporation For The Successful Treatment Of Established Subcutaneous B16.F10 Melanoma, M. Lee Lucus, Loree Heller, Domenico Coppola, Richard Heller

Bioelectrics Publications

Interleukin-12 (IL-12) has been used in numerous immunotherapy protocols against melanoma. However, delivery of IL-12 in the form of recombinant protein can result in severe toxicity, and gene therapy has had limited success against B16.F10 murine melanoma. The purpose of this study was to examine the effectiveness of in vivo electroporation for the delivery of plasmid DNA encoding IL-12 as an antitumor agent against B16.F10 melanoma. We treated mice bearing established B16.F10 melanoma tumors with intratumoral (i.t.) or intramuscular (i.m.) injections of a plasmid encoding IL-12, followed by in vivo electroporation. For i.t. treatments, we used an applicator containing six …


Fluorescence In Situ Hybridization On Sperm Using Alkaline Denaturation, L. J. Aridgides, M. Stacey, L. Brihn, D. Scott, C. Osgood Jan 2002

Fluorescence In Situ Hybridization On Sperm Using Alkaline Denaturation, L. J. Aridgides, M. Stacey, L. Brihn, D. Scott, C. Osgood

Bioelectrics Publications

Fluorescence in situ hybridization (FISH) permits the detection of unique DNA sequences of target DNA within single cells. FISH allows the identifica­tion of DNA sequences within individ­ual cells and readily identifies genetic changes within a mixed population of cells. However, problems arise in main­taining nuclear morphology, particular­ly following harsh denaturation proce­dures where cells are heated to 80°C, causing the nuclear boundary to be­come blurred or the cell to completely burst. In an attempt to preserve cellular morphology and high hybridization ef­ficiency, particularly in fresh tissue samples, we evaluated a FISH protocol using alkaline denaturation in place of heat.


Improved Energy Model For Membrane Electroporation In Biological Cells Subjected To Electrical Pulses, R. P. Joshi, Q. Hu, K. H. Schoenbach, H. P. Hjalmarson Jan 2002

Improved Energy Model For Membrane Electroporation In Biological Cells Subjected To Electrical Pulses, R. P. Joshi, Q. Hu, K. H. Schoenbach, H. P. Hjalmarson

Bioelectrics Publications

A self-consistent model analysis of electroporation in biological cells has been carried out based on an improved energy model. The simple energy model used in the literature is somewhat incorrect and unphysical for a variety of reasons. Our model for the pore formation energy E(r) includes a dependence on pore population and density. It also allows for variable surface tension, incorporates the effects of finite conductivity on the electrostatic correction term, and is dynamic in nature. Self-consistent calculations, based on a coupled scheme involving the Smoluchowski equation and the improved energy model, are presented. It is shown that E(r) becomes …


Theoretical Predictions Of Electromechanical Deformation Of Cells Subjected To High Voltages For Membrane Electroporation, R. P. Joshi, Q. Hu, K. H. Schoenbach, H. P. Hjalmarson Jan 2002

Theoretical Predictions Of Electromechanical Deformation Of Cells Subjected To High Voltages For Membrane Electroporation, R. P. Joshi, Q. Hu, K. H. Schoenbach, H. P. Hjalmarson

Bioelectrics Publications

An electromechanical analysis based on thin-shell theory is presented to analyze cell shape changes in response to external electric fields. This approach can be extended to include osmotic-pressure changes. Our calculations demonstrate that at large fields, the spherical cell geometry can be significantly modified, and even ellipsoidal forms would be inappropriate to account for the deformation. Values of the surface forces obtained from our calculations are in very good agreement with the 1–10 mN/m range for membrane rupture reported in the literature. The results, in keeping with reports in the literature, demonstrate that the final shape depends on membrane thickness. …


Glass Capillary Tube Feeding: A Method For Infecting Nymphal Ixodes Scapularis (Acari: Ixodidae) With The Lyme Disease Spirochete Borrelia Burgdorferi, Anne H. Broadwater, Daniel E. Sonenshine, Wayne L. Hynes, Shane Ceraul, Aravinda M. De Silva Jan 2002

Glass Capillary Tube Feeding: A Method For Infecting Nymphal Ixodes Scapularis (Acari: Ixodidae) With The Lyme Disease Spirochete Borrelia Burgdorferi, Anne H. Broadwater, Daniel E. Sonenshine, Wayne L. Hynes, Shane Ceraul, Aravinda M. De Silva

Biological Sciences Faculty Publications

We evaluated an artificial capillary feeding method to infect nymphal Ixodes scapularis (Say) ticks with Borrelia burgdorferi, the causative agent of Lyme disease. Thirty to 70% of the nymphs were infected after feeding for 2.5 h from glass capillary tubes filled with a solution of spirochetes. Capillary infection was stable and persisted in the nymphs for at least 10 d after feeding. Capillary feeding also maintained natural vector competence patterns because I. scapularis ticks acquired infection unlike Dermacentor variablis (Say), which did not become infected. Capillary infected I. scapularis nymphs were capable of transmitting the infection to naive mice …


Autotrophic Picoplankton: Their Presence And Significance In Marine And Freshwater Ecosystems, Harold G. Marshall Jan 2002

Autotrophic Picoplankton: Their Presence And Significance In Marine And Freshwater Ecosystems, Harold G. Marshall

Biological Sciences Faculty Publications

No abstract provided.


Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: 1985- 2000, Daniel M. Dauer, Michael F. Lane, Harold G. Marshall, Kent E. Carpenter, John R. Donat Jan 2002

Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: 1985- 2000, Daniel M. Dauer, Michael F. Lane, Harold G. Marshall, Kent E. Carpenter, John R. Donat

Status and Trends for Virginia Chesapeake Bay

A detailed overview of the Chesapeake Bay's living resources, water quality, and its major Virginia tributaries.


Methods For Caculating The Chesapeake Bay Benthic Index Of Biotic Integrity, Roberto J. Llansó, Daniel M. Dauer Jan 2002

Methods For Caculating The Chesapeake Bay Benthic Index Of Biotic Integrity, Roberto J. Llansó, Daniel M. Dauer

Benthic Applications

The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI evaluates the ecological condition of a sample by comparing values of key benthic community attributes (“metrics”) to reference values expected under non-degraded conditions in similar habitat types. It is therefore a measure of deviation from reference conditions.

The B-IBI is used by the Chesapeake Bay Benthic Monitoring Program, which is conducted by the Maryland Department of Natural Resources (MD DNR) and by the Virginia Department of Environmental Quality (VA DEQ). The program contains two primary elements: …


Resistance Of The Tick Dermacentor Variabilis (Acari: Ixodidae) Following Challenge With The Bacterium Escherichia Coli (Enterobacteriales: Enterobacteriaceae), Shane M. Ceraul, Daniel E. Sonenshine, Wayne L. Hynes Jan 2002

Resistance Of The Tick Dermacentor Variabilis (Acari: Ixodidae) Following Challenge With The Bacterium Escherichia Coli (Enterobacteriales: Enterobacteriaceae), Shane M. Ceraul, Daniel E. Sonenshine, Wayne L. Hynes

Biological Sciences Faculty Publications

In addition to a soluble response, many invertebrates control bacterial infections by means of phagocytosis or melanotic encapsulation. In some insects, Escherichia coli growth is reported to be inhibited by aggregation/encapsulation. Soluble and phagocytic responses to bacterial challenge have been reported in ticks, but evidence of an aggregation/encapsulation response was reported only for inanimate (araldite) implants. Ticks were challenged by direct inoculation of bacteria into the hemocoel cavity. By plating, no viable E. coli were detected 6 h postinoculation. A direct fluorescence assay (DFA) revealed aggregated bacteria 1 h postinoculation. Furthermore, DFA showed aggregated bacteria at 6, 24, and 48 …


Mechanism For Membrane Electroporation Irreversibility Under High-Intensity, Ultrashort Electrical Pulse Conditions, R. P. Joshi, K. H. Schoenbach Jan 2002

Mechanism For Membrane Electroporation Irreversibility Under High-Intensity, Ultrashort Electrical Pulse Conditions, R. P. Joshi, K. H. Schoenbach

Bioelectrics Publications

An improved electroporation model is used to address membrane irreversibility under ultrashort electric pulse conditions. It is shown that membranes can survive a strong electric pulse and recover provided the pore distribution has a relatively large spread. If, however, the population consists predominantly of larger radii pores, then irreversibility can result. Physically, such a distribution could arise if pores at adjacent sites coalesce. The requirement of close proximity among the pore sites is more easily satisfied in smaller organelles than in outer cell membranes. Model predictions are in keeping with recent observations of cell damage to intracellular organelles (e.g., mitochondria), …


Is There A Threshold Intensity For Aerobic Training In Cardiac Patients?, David P. Swain, Barry Franklin Jan 2002

Is There A Threshold Intensity For Aerobic Training In Cardiac Patients?, David P. Swain, Barry Franklin

Human Movement Studies & Special Education Faculty Publications

Purpose: Recent guidelines have recommended the use of a percentage of oxygen uptake reserve ((V) over dot O2R) for prescribing aerobic exercise intensity for cardiac patients. Moreover, these guidelines suggest that a threshold intensity may exist, below which no improvement in peak oxygen uptake ((V) over dot O-2peak) occurs, The purpose. therefore. was to translate the intensity of aerobic exercise in previous training studies using cardiac patients into %(V) over dot O2R units, and determine whether a threshold intensity exists, Methods: Twenty-three studies, using 28 groups of aerobically trained cardiac patients. were identified in …


Decomposition Dynamics In Restored And Naturally Recovering Atlantic White Cedar (Chamaecyparis Thyoides) Wetlands, Edward Ratcliffe Crawford Jan 2002

Decomposition Dynamics In Restored And Naturally Recovering Atlantic White Cedar (Chamaecyparis Thyoides) Wetlands, Edward Ratcliffe Crawford

Biological Sciences Theses & Dissertations

Restoration efforts and ecologically based management practices for Atlantic white cedar wetlands have recently focused on soil organic matter sequestration and aggradation as critical ecosystem functions in the maintenance of this imperiled community type. This work addresses how developmental stage, litter quality and environmental conditions influenced above ground leaf litter and below ground root decay in naturally regenerating and restored Atlantic white cedar wetlands. Using standard litterbags for leaf litter and a modified litterbag technique for roots, decay dynamics of naturally regenerating and restored Atlantic white cedar stands were measured to compare ecosystem development trends with restoration conditions. Effects on …


Apoptosis Pathways: Presence And Significance In Ejaculated Human Spermatozoa, Steven Lewis Taylor Jan 2002

Apoptosis Pathways: Presence And Significance In Ejaculated Human Spermatozoa, Steven Lewis Taylor

Theses and Dissertations in Biomedical Sciences

Ejaculated sperm display markers that are indicative of apoptosis in somatic cells. The question remains as to whether sperm have operative apoptosis mechanisms. The aim of this research was to test the hypothesis that apoptosis markers in sperm and somatic cells are different.

Ejaculated human sperm from patients and donors were separated into high and low motility fractions using Percoll™ gradients. Contaminating cells were removed using anti-CD45 conjugated paramagnetic beads. Fractions were divided into groups: staurosporine, anti-Fas antibody, and hydrogen peroxide treated and control. Direct enzymatic measurement of caspase activity, flow cytometric evaluation of phosphatidylserine translocation, immunoblots, and immunocytochemistry were …


In Vivo Effect Of Leukemia Inhibitory Factor (Lif) And An Anti-Lif Polyclonal Antibody On Murine Embryo And Fetal Development Following Exposure At The Time Of Transcervical Blastocyst Transfer, Michael H. Mitchell, R. James Swanson, Sergio Oehninger Jan 2002

In Vivo Effect Of Leukemia Inhibitory Factor (Lif) And An Anti-Lif Polyclonal Antibody On Murine Embryo And Fetal Development Following Exposure At The Time Of Transcervical Blastocyst Transfer, Michael H. Mitchell, R. James Swanson, Sergio Oehninger

Biological Sciences Faculty Publications

Leukemia inhibitory factor (LIF) enhances in vitro murine preimplantation development in a time- and dose-dependent fashion. Knockout experiments have demonstrated that endometrial LIF is essential for in vivo murine implantation. We assessed the impact of LIF and an anti-LIF polyclonal antibody (pab) on in vivo development and developed a novel and successful nonsurgical method of embryo transfer for this species, a transcervical blastocyst transfer technique. The objectives of this study were to evaluate the effects of LIF and the anti-LIF pab on 1) implantation, resorption, pregnancy, and viability rates and 2) the overall structural and skeletal development. Two-cell embryos were …


Rickettsial Infection In Dermacentor Variabilis (Acari : Ixodidae) Inhibits Transovarial Transmission Of A Second Rickettsia, Kevin R. Macaluso, Daniel E. Sonenshine, Shane M. Ceraul, Abdu F. Azad Jan 2002

Rickettsial Infection In Dermacentor Variabilis (Acari : Ixodidae) Inhibits Transovarial Transmission Of A Second Rickettsia, Kevin R. Macaluso, Daniel E. Sonenshine, Shane M. Ceraul, Abdu F. Azad

Biological Sciences Faculty Publications

This study examined the ability of ticks to maintain multiple species of spotted fever group rickettsiae via transovarial transmission. Using a capillary feeding method, previously established Rickettsia montana- and Rickettsia rhipicephali-infected cohorts of Dermacentor variabilis (Say) were exposed to R. rhipicephali and R. montana, respectively, in two reciprocal challenge experiments. Eggs collected from individual females, for two successive generations, of each cohort were assessed for rickettsial infection by polymerase chain reaction for each challenge experiment. Assessment of the eggs from challenged ticks identified that both R. montana- and R. rhipicephali-infected ticks were refractory to their …


Response Of Anchovy (Engaulis Ringens) Off Northern Chile To The 1997-1999 El Niño-La Niña Sequence, José L. Blanco, Patricio Barria, Jorge Castillo, Larry P. Atkinson Jan 2002

Response Of Anchovy (Engaulis Ringens) Off Northern Chile To The 1997-1999 El Niño-La Niña Sequence, José L. Blanco, Patricio Barria, Jorge Castillo, Larry P. Atkinson

CCPO Publications

No abstract provided.


Isoetes Toximontana (Isoetaceae), A New Quillwort With Green Megaspores From The Northern Cape Of South Africa, Lytton John Musselman, J. P. Roux Jan 2002

Isoetes Toximontana (Isoetaceae), A New Quillwort With Green Megaspores From The Northern Cape Of South Africa, Lytton John Musselman, J. P. Roux

Biological Sciences Faculty Publications

Isoetes toximontana is only the second quillwort reported from the Northern Cape region in South Africa. It occurs in shallow water on the Gifberg. Megaspores are uniformly tuberculate on the proximal surface; their distal surfaces may have occasional rugi along with bullae. They are olive green when dry. Microspores are brown and aculeate. Preliminary field studies suggest that an unexpected diversity of quillworts is found in this region.


Distribution Of The Euryhaline Squid Lolliguncula Brevis In Chesapeake Bay: Effects Of Selected Abiotic Factors, I. K. Bartol, R. Mann, M. Vecchione Jan 2002

Distribution Of The Euryhaline Squid Lolliguncula Brevis In Chesapeake Bay: Effects Of Selected Abiotic Factors, I. K. Bartol, R. Mann, M. Vecchione

Biological Sciences Faculty Publications

The majority of cephalopods are thought to have limitations arising from physiology and locomotion that exclude them from shallow, highly variable, euryhaline environments. The brief squid Lolliguncula brevis may be a notable exception because it tolerates low salinities, withstands a wide range of environmental conditions, and swims readily in shallow water. Little is known about the distribution of L. brevis in Chesapeake Bay, a diverse and highly variable estuary. Therefore, a survey of L. brevis was conducted in the Virginia portion of Chesapeake Bay from 1993 to 1997 using a 9.1 m otter trawl, and the effects of selected factors …


Evidence For Infanticide In Bottlenose Dolphins Of The Western North Atlantic, Dale G. Dunn, Susan G. Barco, D. Ann Pabst, William A. Mclellan Jan 2002

Evidence For Infanticide In Bottlenose Dolphins Of The Western North Atlantic, Dale G. Dunn, Susan G. Barco, D. Ann Pabst, William A. Mclellan

Biological Sciences Faculty Publications

Nine bottlenose dolphin (Tursiops truncatus) calves that stranded in Virginia in 1996 and 1997 died of severe blunt-force trauma. Injuries were concentrated on the head and chest and multiple rib fractures, lung lacerations, and soft tissue contusions were prominent. Skeletal and/or soft tissue trauma occurred bilaterally in all of the calves. One had a bite wound across the left mandible that exhibited deep punctures consistent with the tooth placement in an adult bottlenose dolphin. The lesions were not compatible with predation, boat strike, fisheries interactions, rough-surf injury, or blast injury. However, they were similar to traumatic injuries described in stranded …


Microbial Ecology Of Ballast Water During A Transoceanic Voyage And The Effects Of Open-Ocean Exchange, Lisa A. Drake, Gregory M. Ruiz, Bella S. Galil, Timothy L. Mullady, Daniela O. Friedmann, Fred C. Dobbs Jan 2002

Microbial Ecology Of Ballast Water During A Transoceanic Voyage And The Effects Of Open-Ocean Exchange, Lisa A. Drake, Gregory M. Ruiz, Bella S. Galil, Timothy L. Mullady, Daniela O. Friedmann, Fred C. Dobbs

OES Faculty Publications

The only procedure used frequently to reduce the risk of invasion by ballast-mediated biota is open-ocean exchange of ballast water, a procedure in which vessels release coastal water and replace it with oceanic water. Limited information exists concerning the effects of transport upon the aquatic microbial community throughout transit and following open-ocean exchange, A transoceanic voyage aboard a commercial bulk carrier afforded us the opportunity to sample the microbial community in exchanged and unexchanged ballast-water holds during the journey from Hadera, Israel to Baltimore, USA. Five days following the exchange process, all microbial metrics tested (i.e. bacteria concentration, virus-like particle …


Impact Of Sea Grass Density On Carbonate Dissolution In Bahamian Sediments, David J. Burdige, Richard C. Zimmerman Jan 2002

Impact Of Sea Grass Density On Carbonate Dissolution In Bahamian Sediments, David J. Burdige, Richard C. Zimmerman

OES Faculty Publications

Carbonate dissolution has been widely observed in shallow water tropical sediments. However, sediment budgets C have generally not been closed with respect to the amount of acid required to produce the observed carbonate dissolution. Recently it has been suggested that enhanced oxygen transport into sediments through the roots and rhizomes of sea grasses might play a role in resolving this mass balance problem. We conducted studies of sea grass-carbonate sediment interactions around Lee Stocking Island, Exuma Islands, Bahamas to further examine this problem. Our studies showed that alkalinity, total dissolved inorganic carbon (ΣCO2) and Ca2+ increased with …


Effects Of Nonequilibrium Atmospheric Pressure Plasmas On The Heterotrophic Pathways Of Bacteria And On Their Cell Morphology, Mounir Laroussi, J. Paul Richardson, Fred C. Dobbs Jan 2002

Effects Of Nonequilibrium Atmospheric Pressure Plasmas On The Heterotrophic Pathways Of Bacteria And On Their Cell Morphology, Mounir Laroussi, J. Paul Richardson, Fred C. Dobbs

OES Faculty Publications

To date, most research on the interaction of nonequilibrium, atmospheric pressure plasma discharges with bacteria has concentrated on the germicidal effects. Therefore, published results deal mainly with killing efficacy and little attention is given to physical mechanisms and biochemical pathways and their potential alterations when cells of microorganisms are exposed to the plasma. In this letter, an attempt to investigate the effects of plasma exposure on the biochemical pathways of bacteria is presented. In addition, using electron microscopy, we investigate if any gross morphological changes take place when cells are exposed to a lethal dose of plasma. We are testing …


The Transformation Of Iodate To Iodide In Marine Phytoplankton Cultures, George T. F. Wong, Ajcharaporn U. Piumsomboon, William M. Dunstan Jan 2002

The Transformation Of Iodate To Iodide In Marine Phytoplankton Cultures, George T. F. Wong, Ajcharaporn U. Piumsomboon, William M. Dunstan

OES Faculty Publications

Six species of phytoplankton, representing 6 major phylogenetic groups (2 oceanic species: a cyanobacteria, Synechococcus sp., and a coccolithophorid, Emiliania huxleyi; and 4 coastal species: a prasinophyte, Tetraselmis sp., the green algae Dunaliella tertiolecta, the diatom Skeletonema costatum and a dinoflagellate Amphidinium carterae) were tested for their ability to reduce iodate to iodide in batch cultures. They all did so to varying degrees. Thus, the reduction of iodate to iodide by phytoplankton may be a general phenomenon in the marine environment. At ambient concentrations of iodate, the rates of depletion of iodate and appearance of …


Phosphorus Dynamics In Cultures And Natural Populations Of Trichodesmium Spp, Margaret R. Mulholland, Sheri Floge, Edward J. Carpenter, Douglas G. Capone Jan 2002

Phosphorus Dynamics In Cultures And Natural Populations Of Trichodesmium Spp, Margaret R. Mulholland, Sheri Floge, Edward J. Carpenter, Douglas G. Capone

OES Faculty Publications

Trichodesmium spp. fix atmospheric N2 and so an element other than N limits production by these species in the oligotrophic ocean. Because dissolved inorganic phosphorus (DIP) is in short supply in many marine systems, it has been hypothesized that P is a growth-limiting nutrient for these species in nature. However, Trichodesmium is capable of hydrolyzing dissolved organic P (DOP) compounds and the inorganic products from hydrolysis may provide an additional source of P for growth. We investigated P dynamics and alkaline phosphatase activity in cultures and natural populations of Trichodesmium from the Atlantic Ocean and the north coast of …


Peptide Hydrolysis, Amino Acid Oxidation, And Nitrogen Uptake In Communities Seasonally Dominated By Aureococcus Anophagefferens, Margaret R. Mulholland, Christopher J. Gobler, Cindy Lee Jan 2002

Peptide Hydrolysis, Amino Acid Oxidation, And Nitrogen Uptake In Communities Seasonally Dominated By Aureococcus Anophagefferens, Margaret R. Mulholland, Christopher J. Gobler, Cindy Lee

OES Faculty Publications

Elevated levels of dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN) are among the factors implicated in the initiation of algal blooms. However, the degree to which phytoplankton augment their autotrophic metabolism with heterotrophic uptake of organic carbon that is associated with DON is unknown. We evaluated the relative importance of peptide hydrolysis, amino acid oxidation, and amino acid uptake over a seasonal cycle in an embayment on Long Island, New York, that had high concentrations of dissolved organic matter (DOM) and a bloom of the brown tide pelagophyte, Aureococcus anophagefferens. Amino acids were a significant component (up …