Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Louisiana State University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 5881 - 5910 of 9778

Full-Text Articles in Entire DC Network

Tc-99m Pyrophosphate Imaging Of Poloxamer-Treated Electroporated Skeletal Muscle In An In Vivo Rat Model, Kenneth L. Matthews, John N. Aarsvold, Robert A. Mintzer, Chin Tu Chen, Raphael C. Lee Sep 2006

Tc-99m Pyrophosphate Imaging Of Poloxamer-Treated Electroporated Skeletal Muscle In An In Vivo Rat Model, Kenneth L. Matthews, John N. Aarsvold, Robert A. Mintzer, Chin Tu Chen, Raphael C. Lee

Faculty Publications

Objective: This study investigates whether 99mTc pyrophosphate (PYP) imaging provides a quantitative non-invasive assessment of the extent of electroporation injury, and of the effect of poloxamer in vivo on electroporated skeletal muscle. Methods: High-voltage electrical shock was used to produce electroporation injury in an anesthetized rat's hind limb. In each experiment, the injured limb was treated intravenously by either poloxamer-188, dextran, or saline, and subsequently imaged with 99mTc PYP. The radiotracer's temporal behavior among the experimental groups was compared using curve fitting of time-activity curves from the dynamic image data. Results: The washout kinetics of 99mTc PYP changed in proportion …

Go to article

Effects Of Resistant Starch, A Non-Digestible Fermentable Fiber, On Reducing Body Fat, Michael J. Keenan, Jun Zhou, Kathleen L. Mccutcheon, Anne M. Raggio, H. Gale Bateman, Emily Todd, Christina K. Jones, Richard T. Tulley, Sheri Melton, Roy J. Martin, Maren Hegsted Sep 2006

Effects Of Resistant Starch, A Non-Digestible Fermentable Fiber, On Reducing Body Fat, Michael J. Keenan, Jun Zhou, Kathleen L. Mccutcheon, Anne M. Raggio, H. Gale Bateman, Emily Todd, Christina K. Jones, Richard T. Tulley, Sheri Melton, Roy J. Martin, Maren Hegsted

Faculty Publications

Objective: To assess the effects of energy dilution with non-fermentable and fermentable fibers on abdominal fat and gut peptide YY (PYY) and glucagon-like peptide (GLP)-1 expressions, three rat studies were conducted to: determine the effects of energy dilution with a non-ferment-able fiber, compare similar fiber levels of fermentable and non-fermentable fibers, and compare similar metabolizable energy dilutions with fermentable and non-fermentable fibers. Research Methods and Procedures: In Study 1, rats were fed one of three diets with different metabolizable energy densities. In Study 2, rats were fed diets with similar fiber levels using high amylose-resistant cornstarch (RS) or methylcellulose. In …

Go to article

Hiv-1 Dna/Mva Vaccination Reduces The Per Exposure Probability Of Infection During Repeated Mucosal Shiv Challenges, Dennis Ellenberger, Ronald A. Otten, Bin Li, Michael Aidoo, I. Vanessa Rodriguez, Carlos A. Sariol, Melween Martinez, Michael Monsour, Linda Wyatt, Michael G. Hudgens, Edmundo Kraiselburd, Bernard Moss, Harriet Robinson, Thomas Folks, Salvatore Butera Aug 2006

Hiv-1 Dna/Mva Vaccination Reduces The Per Exposure Probability Of Infection During Repeated Mucosal Shiv Challenges, Dennis Ellenberger, Ronald A. Otten, Bin Li, Michael Aidoo, I. Vanessa Rodriguez, Carlos A. Sariol, Melween Martinez, Michael Monsour, Linda Wyatt, Michael G. Hudgens, Edmundo Kraiselburd, Bernard Moss, Harriet Robinson, Thomas Folks, Salvatore Butera

Faculty Publications

Historically, HIV vaccines specifically designed to raise cellular immunity resulted in protection from disease progression but not infection when tested in monkeys challenged with a single high virus exposure. An alternative approach, more analogous to human sexual exposures, is to repetitively challenge immunized monkeys with a much lower dose of virus until systemic infection is documented. Using these conditions to mimic human sexual transmission, we found that a multi-protein DNA/MVA HIV-1 vaccine is indeed capable of protecting rhesus monkeys against systemic infection when repeatedly challenged with a highly heterologous immunodeficiency virus (SHIV). Furthermore, this repetitive challenge approach allowed us to …

Go to article

Stereoselectivity Of 8-Oh-Dpat Toward The Serotonin 5-Ht1a Receptor: Biochemical And Molecular Modeling Study, Joanna Dabrowska, Michal Brylinski Aug 2006

Stereoselectivity Of 8-Oh-Dpat Toward The Serotonin 5-Ht1a Receptor: Biochemical And Molecular Modeling Study, Joanna Dabrowska, Michal Brylinski

Faculty Publications

The great majority of pharmacological investigations of 5-HT1A receptors' reactivity has been performed using racemic 8-OH-DPAT, therefore the biochemical as well as behavioral profiles of both 8-OH-DPAT enantiomers are not circumstantiated. In the biochemical study capability of racemic 8-OH-DPAT (0.05, 0.1 mg/kg s.c.) and its counterparts R-8-OH-DPAT (0.05, 0.1 mg/kg s.c.) and S-8-OH-DPAT (0.05, 0.1 mg/kg s.c.) to influence 5-HT synthesis rate in rats' prefrontal cortex, hypothalamus, hippocampus and brainstem was evaluated by HPLC/ED technique. Biochemical results are supported by the exhaustive computational study of possible differences between R- and S-enantiomer toward the 5-HT1A receptor. A reliable 3D model of …

Go to article

Exposure Of Neonates To Respiratory Syncytial Virus Is Critical In Determining Subsequent Airway Response In Adults, Dahui You, David Becnel, Kai Wang, Michael Ripple, Melissa Daly, Stephania A. Cormier Aug 2006

Exposure Of Neonates To Respiratory Syncytial Virus Is Critical In Determining Subsequent Airway Response In Adults, Dahui You, David Becnel, Kai Wang, Michael Ripple, Melissa Daly, Stephania A. Cormier

Faculty Publications

Background: Respiratory syncytial virus (RSV) is the most common cause of acute bronchiolitis in infants and the elderly. Furthermore, epidemiological data suggest that RSV infection during infancy is a potent trigger of subsequent wheeze and asthma development. However, the mechanism by which RSV contributes to asthma is complex and remains largely unknown. A recent study indicates that the age of initial RSV infection is a key factor in determining airway response to RSV rechallenge. We hypothesized that severe RSV infection during neonatal development significantly alters lung structure and the pulmonary immune micro-environment; and thus, neonatal RSV infection is crucial in …

Go to article

Parasites In A Biodiversity Hotspot: A Survey Of Hematozoa And A Molecular Phylogenetic Analysis Of Plasmodium In New Guinea Skinks, Christopher C. Austin, Susan L. Perkins Aug 2006

Parasites In A Biodiversity Hotspot: A Survey Of Hematozoa And A Molecular Phylogenetic Analysis Of Plasmodium In New Guinea Skinks, Christopher C. Austin, Susan L. Perkins

Faculty Publications

A sample of 204 skinks (Squamata: Scincidae) from 10 genera representing 24 species were collected from 10 different localities in New Guinea and examined for blood parasites. Hemogregarines, trypanosomes, microfilarial worms, and 8 infections showing 2 distinct morphological types of malaria parasites (Plasmodium sp.) were observed. Molecular sequence data, in the form of mitochondrial cytochrome b sequences from the Plasmodium infections, showed 2 distinct clades of parasites, 1 in Sphenomorphus jobiense hosts and 1 in Emoia spp., which correspond to the 2 morphotypes. There was substantial genetic variation between the 2 clades, as well as within the clade of Emoia …

Go to article

Rickettsia Felis From Cat Fleas: Isolation And Culture In A Tick-Derived Cell Line, Walairat Pornwiroon, Susan S. Pourciau, Lane D. Foil, Kevin R. Macaluso Aug 2006

Rickettsia Felis From Cat Fleas: Isolation And Culture In A Tick-Derived Cell Line, Walairat Pornwiroon, Susan S. Pourciau, Lane D. Foil, Kevin R. Macaluso

Faculty Publications

Rickettsia felis, the etiologic agent of spotted fever, is maintained in cat fleas by vertical transmission and resembles other tick-borne spotted fever group rickettsiae. In the present study, we utilized an Ixodes scapularis-derived tick cell line, ISE6, to achieve isolation and propagation of R. felis. A cytopathic effect of increased vacuolization was commonly observed in R. felis-infected cells, while lysis of host cells was not evident despite large numbers of rickettsiae. Electron microscopy identified rickettsia-like organisms in ISE6 cells, and sequence analyses of portions of the citrate synthase (gltA), 16S rRNA, Rickettsia genus-specific 17-kDa antigen, and spotted fever group-specific outer …

Go to article

The Drosophila Boundary Element-Associated Factors Beaf-32a And Beaf-32b Affect Chromatin Structure, Matthew K. Gilbert, Yian Yee Tan, Craig M. Hart Aug 2006

The Drosophila Boundary Element-Associated Factors Beaf-32a And Beaf-32b Affect Chromatin Structure, Matthew K. Gilbert, Yian Yee Tan, Craig M. Hart

Faculty Publications

Binding sites for the Drosophila boundary element-associated factors BEAF-32A and -32B are required for the insulator activity of the scs' insulator. BEAF binds to hundreds of sites on polytene chromosomes, indicating that BEAF-utilizing insulators are an important class in Drosophila. To gain insight into the role of BEAF in flies, we designed a transgene encoding a dominant-negative form of BEAF under GAL4 UAS control. This BID protein encompasses the BEAF self-interaction domain. Evidence is provided that BID interacts with BEAF and interferes with scs' insulator activity and that BEAF is the major target of BID in vivo. BID expression during …

Go to article

Health In Cuba, Richard S. Cooper, Joan F. Kennelly, Pedro Orduñez-Garcia Aug 2006

Health In Cuba, Richard S. Cooper, Joan F. Kennelly, Pedro Orduñez-Garcia

Faculty Publications

The poorer countries of the world continue to struggle with an enormous health burden from diseases that we have long had the capacity to eliminate. Similarly, the health systems of some countries, rich and poor alike, are fragmented and inefficient, leaving many population groups underserved and often without health care access entirely. Cuba represents an important alternative example where modest infrastructure investments combined with a well-developed public health strategy have generated health status measures comparable with those of industrialized countries. Areas of success include control of infectious diseases, reduction in infant mortality, establishment of a research and biotechnology industry, and …

Go to article

Classical Biological Control Of The Papaya Mealybug, Paracoccus Marginatus (Hemiptera: Pseudococcidae) In The Republic Of Palau, R. Muniappan, D. E. Meyerdirk, F. M. Sengebau, D. D. Berringer, G. V.P. Reddy Jul 2006

Classical Biological Control Of The Papaya Mealybug, Paracoccus Marginatus (Hemiptera: Pseudococcidae) In The Republic Of Palau, R. Muniappan, D. E. Meyerdirk, F. M. Sengebau, D. D. Berringer, G. V.P. Reddy

Faculty Publications

The papaya mealybug (PM), Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), a pest in Central America and the Caribbean, was noted to have established on Palau in March 2003 and was causing serious damage to papaya, plumeria, hibiscus, and other plants. The parasitoids Anagyrus loecki Noyes, Pseudleptomastix mexicana Noyes and Schauff, and Acerophagus papayae Noyes and Schauff (Hymenoptera: Encyrtidae) totaling 24,586 were imported from Puerto Rico and field released in Palau from August 2003 to June 2004. Anagyrus loecki and A. papayae appear to be promising biological control agents of PM in Palau. No field recovery of P. …

Go to article

The Importance Of Demographic Niches To Tree Diversity, Richard Condit, Peter Ashton, Sarayudh Bunyavejchewin, H. S. Dattaraja, Stuart Davies, Shameema Esufali, Corneille Ewango, Robin Foster, I. A.U.N. Gunatilleke, C. V.S. Gunatilleke, Pamela Hall, Kyle E. Harms, Terese Hart, Consuelo Hernandez, Stephen Hubbell, Akira Itoh, Somboon Kiratiprayoon, James Lafrankie, Suzanne Loo De Lao, Jean Remy Makana, Md Nur Supardi Noor, Abdul Rahman Kassim, Sabrina Russo, Raman Sukumar, Cristián Samper, Hebbalalu S. Suresh, Sylvester Tan, Sean Thomas, Renato Valencia, Martha Vallejo, Gorky Villa, Tommaso Zillio Jul 2006

The Importance Of Demographic Niches To Tree Diversity, Richard Condit, Peter Ashton, Sarayudh Bunyavejchewin, H. S. Dattaraja, Stuart Davies, Shameema Esufali, Corneille Ewango, Robin Foster, I. A.U.N. Gunatilleke, C. V.S. Gunatilleke, Pamela Hall, Kyle E. Harms, Terese Hart, Consuelo Hernandez, Stephen Hubbell, Akira Itoh, Somboon Kiratiprayoon, James Lafrankie, Suzanne Loo De Lao, Jean Remy Makana, Md Nur Supardi Noor, Abdul Rahman Kassim, Sabrina Russo, Raman Sukumar, Cristián Samper, Hebbalalu S. Suresh, Sylvester Tan, Sean Thomas, Renato Valencia, Martha Vallejo, Gorky Villa, Tommaso Zillio

Faculty Publications

Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution Of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, …

Go to article

Biocatalytic And Antimetastatic Studies Of The Marine Cembranoids Sarcophine And 2-Epi-16-Deoxysarcophine, Swapnali S. Sawant, Diaa T.A. Youssef, Jane Reiland, Melissa Ferniz, Dario Marchetti, Khalid A. El Sayed Jul 2006

Biocatalytic And Antimetastatic Studies Of The Marine Cembranoids Sarcophine And 2-Epi-16-Deoxysarcophine, Swapnali S. Sawant, Diaa T.A. Youssef, Jane Reiland, Melissa Ferniz, Dario Marchetti, Khalid A. El Sayed

Faculty Publications

The soft coral Sarcophyton glaucum is a rich resource of several bioactive cembranoids. Sarcophytol A (1) and sarcophine (2) are cembranoid diterpenes reported from this soft coral and extensively investigated for their cancer chemopreventive properties. This study aimed at investigating the antimetastatic potential of the major cembranoids, sarcophine (2) and 2-epi-16-deoxysarcophine (3), from the Red Sea soft coral S. glaucum. Biocatalytic transformation of 3 using Rhizopus stolonifer ATCC 6227a and Absidia spinosa ATCC 6648 afforded four new metabolites, 5-7 and 9, along with the known 9α-hydroxysarcophine (8). Sarcophine, 2-epi-16-deoxysarcophine, and metabolites 5-9 revealed significant antimetastatic activity against the highly metastatic …

Go to article

Reca And Rada Proteins Of Brucella Abortus Do Not Perform Overlapping Protective Dna Repair Functions Following Oxidative Burst, Christelle M. Roux, Natha J. Booth, Bryan H. Bellaire, Jason M. Gee, R. Martin Roop, Michael E. Kovach, Renée M. Tsolis, Philip H. Elzer, Don G. Ennis Jul 2006

Reca And Rada Proteins Of Brucella Abortus Do Not Perform Overlapping Protective Dna Repair Functions Following Oxidative Burst, Christelle M. Roux, Natha J. Booth, Bryan H. Bellaire, Jason M. Gee, R. Martin Roop, Michael E. Kovach, Renée M. Tsolis, Philip H. Elzer, Don G. Ennis

Faculty Publications

Very little is known about the role of DNA repair networks in Brucella abortus and its role in pathogenesis. We investigated the roles of RecA protein, DNA repair, and SOS regulation in B. abortus. While recA mutants in most bacterial species are hypersensitive to UV damage, surprisingly a B. abortus recA null mutant conferred only modest sensitivity. We considered the presence of a second RecA protein to account for this modest UV sensitivity. Analyses of the Brucella spp. genomes and our molecular studies documented the presence of only one recA gene, suggesting a RecA-independent repair process. Searches of the available …

Go to article

Louisiana Agriculture Summer, 2006, Lsu Agcenter Jul 2006

Louisiana Agriculture Summer, 2006, Lsu Agcenter

Louisiana Agriculture

No abstract provided.

Go to article

Species-Habitat Associations In A Sri Lankan Dipterocarp Forest, C. V.S. Gunatilleke, I. A.U.N. Gunatilleke, S. Esufali, K. E. Harms, P. M.S. Ashton, D. F.R.P. Burslem, P. S. Ashton Jul 2006

Species-Habitat Associations In A Sri Lankan Dipterocarp Forest, C. V.S. Gunatilleke, I. A.U.N. Gunatilleke, S. Esufali, K. E. Harms, P. M.S. Ashton, D. F.R.P. Burslem, P. S. Ashton

Faculty Publications

Forest structure and species distribution patterns were examined among eight topographically defined habitats for the 205 species with stems ≥ 1 cm dbh inhabiting a 25-ha plot in the Sinharaja rain forest, Sri Lanka. The habitats were steep spurs, less-steep spurs, steep gullies and less-steep gullies, all at either lower or upper elevations. Mean stem density was significantly greater on the upper spurs than in the lower, less-steep gullies. Stem density was also higher on spurs than in gullies within each elevation category and in each upper-elevation habitat than in its corresponding lower-elevation habitat. Basal area varied less among habitats, …

Go to article

Stat5 Activators Modulate Acyl Coa Oxidase (Aox) Expression In Adipocytes And Stat5a Binds To The Aox Promoter In Vitro, Ann A. Coulter, Jacqueline M. Stephens Jun 2006

Stat5 Activators Modulate Acyl Coa Oxidase (Aox) Expression In Adipocytes And Stat5a Binds To The Aox Promoter In Vitro, Ann A. Coulter, Jacqueline M. Stephens

Faculty Publications

Growth hormone (GH) diminishes adipose tissue mass in vivo and prolactin (PRL) can also modulate adipocyte metabolism. Both GH and PRL are potent activators of STAT5 and exert a variety of effects on adipocyte gene expression. In this study, we have demonstrated that GH and PRL increase the mRNA of acyl CoA oxidase in 3T3-L1 adipocytes. We also identified seven putative STAT elements in the murine AOX promoter. We observed that GH modulates protein binding to the majority of these promoter elements. However, GH induced very potent binding to -1841 to -1825 of the murine AOX promoter. EMSA supershift analysis …

Go to article

Molecular Fluorescence, Phosphorescence, And Chemiluminescence Spectrometry, Kristin A. Fletcher, Sayo O. Fakayode, Mark Lowry, Sheryl A. Tucker, Sharon L. Neal, Irene W. Kimaru, Matthew E. Mccarroll, Gabor Patonay, Philip B. Oldham, Oleksandr Rusin, Robert M. Strongin, Isiah M. Warner Jun 2006

Molecular Fluorescence, Phosphorescence, And Chemiluminescence Spectrometry, Kristin A. Fletcher, Sayo O. Fakayode, Mark Lowry, Sheryl A. Tucker, Sharon L. Neal, Irene W. Kimaru, Matthew E. Mccarroll, Gabor Patonay, Philip B. Oldham, Oleksandr Rusin, Robert M. Strongin, Isiah M. Warner

Faculty Publications

No abstract provided.

Go to article

Origin And Health Impacts Of Emissions Of Toxic By-Products And Fine Particles From Combustion And Thermal Treatment Of Hazardous Wastes And Materials, Stephania A. Cormier, Slawo Lomnicki, Wayne Backes, Barry Dellinger Jun 2006

Origin And Health Impacts Of Emissions Of Toxic By-Products And Fine Particles From Combustion And Thermal Treatment Of Hazardous Wastes And Materials, Stephania A. Cormier, Slawo Lomnicki, Wayne Backes, Barry Dellinger

Faculty Publications

High-temperature, controlled incineration and thermal treatment of contaminated soils, sediments, and wastes at Superfund sites are often preferred methods of remediation of contaminated sites under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 and related legislation. Although these methods may be executed safely, formation of toxic combustion or reaction by-products is still a cause of concern. Emissions of polycyclic aromatic hydrocarbons (PAHs); chlorinated hydrocarbons (CHCs), including polychlorinated dibenzo-p-dioxins and dibenzofurans; and toxic metals (e.g., chromium VI) have historically been the focus of combustion and health effects research. However, fine particulate matter (PM) and ultrafine PM, which have been …

Go to article

Pivotal Advance: Eosinophil Infiltration Of Solid Tumors Is An Early And Persistent Inflammatory Host Response, Stephania A. Cormier, Anna G. Taranova, Carrie Bedient, Thanh Nguyen, Cheryl Protheroe, Ralph Pero, Dawn Dimina, Sergei I. Ochkur, Katie O'Neill, Dana Colbert, Theresa R. Lombari, Stephanie Constant, Michael P. Mcgarry, James J. Lee, Nancy A. Lee Jun 2006

Pivotal Advance: Eosinophil Infiltration Of Solid Tumors Is An Early And Persistent Inflammatory Host Response, Stephania A. Cormier, Anna G. Taranova, Carrie Bedient, Thanh Nguyen, Cheryl Protheroe, Ralph Pero, Dawn Dimina, Sergei I. Ochkur, Katie O'Neill, Dana Colbert, Theresa R. Lombari, Stephanie Constant, Michael P. Mcgarry, James J. Lee, Nancy A. Lee

Faculty Publications

Tumor-associated eosinophilia has been observed in numerous human cancers and several tumor models in animals; however, the details surrounding this eosinophilia remain largely undefined and anecdotal. We used a B16-F10 melanoma cell injection model to demonstrate that eosinophil infiltration of tumors occurred from the earliest palpable stages with significant accumulations only in the necrotic and capsule regions. Furthermore, the presence of diffuse extracellular matrix staining for eosinophil major basic protein was restricted to the necrotic areas of tumors, indicating that eosinophil degranulation was limited to this region. Antibody-mediated depletion of CD4+ T cells and adoptive transfer of eosinophils suggested, respectively, …

Go to article

Do Geese Fully Develop Brood Patches? A Histological Analysis Of Lesser Snow Geese (Chen Caerulescens Caerulescens) And Ross's Geese (C. Rossii), Jón Einar Jónsson, Alan D. Afton, Dominique G. Homberger, William G. Henk, Ray T. Alisauskas Jun 2006

Do Geese Fully Develop Brood Patches? A Histological Analysis Of Lesser Snow Geese (Chen Caerulescens Caerulescens) And Ross's Geese (C. Rossii), Jón Einar Jónsson, Alan D. Afton, Dominique G. Homberger, William G. Henk, Ray T. Alisauskas

Faculty Publications

Most birds develop brood patches before incubation; epidermis and dermis in the brood patch region thicken, and the dermal connective tissue becomes increasingly vascularized and infiltrated by leukocytes. However, current dogma states that waterfowl incubate without modifications of skin within the brood patch region. The incubation periods of lesser snow geese (Chen caerulescens caerulescens; hereafter called snow geese) and Ross's geese (C. rossii) are 2-6 days shorter than those of other goose species; only females incubate. Thus, we hypothesized that such short incubation periods would require fully developed brood patches for sufficient heat transfer from incubating parents to eggs. We …

Go to article

Systematics And Historical Biogeography Of Greater Antillean Cichlidae, Prosanta Chakrabarty Jun 2006

Systematics And Historical Biogeography Of Greater Antillean Cichlidae, Prosanta Chakrabarty

Faculty Publications

A molecular phylogenetic analysis recovers a pattern consistent with a drift vicariance scenario for the origin of Greater Antillean cichlids. This phylogeny, based on mitochondrial and nuclear genes, reveals that clades on different geographic regions diverged concurrently with the geological separation of these areas. Middle America was initially colonized by South American cichlids in the Cretaceous, most probably through the Cretaceous Island Arc. The separation of Greater Antillean cichlids and their mainland Middle American relatives was caused by a drift vicariance event that took place when the islands became separated from Yucatan in the Eocene. Greater Antillean cichlids are monophyletic …

Go to article

Toxic And Contaminant Concerns Generated By Hurricane Katrina, Danny D. Reible, Charles N. Haas, John H. Pardue, William J. Walsh Jun 2006

Toxic And Contaminant Concerns Generated By Hurricane Katrina, Danny D. Reible, Charles N. Haas, John H. Pardue, William J. Walsh

Faculty Publications

No abstract provided.

Go to article

Small-Scale Fuel Variation Alters Fire Intensity And Shrub Abundance In A Pine Savanna, Jarrod M. Thaxton, William J. Platt May 2006

Small-Scale Fuel Variation Alters Fire Intensity And Shrub Abundance In A Pine Savanna, Jarrod M. Thaxton, William J. Platt

Faculty Publications

Small-scale variation in fire intensity and effects may be an important source of environmental heterogeneity in frequently burned plant communities. We hypothesized that variation in fire intensity resulting from local differences in fuel loads produces heterogeneity in pine savanna ground cover by altering shrub abundance. To test this hypothesis, we experimentally manipulated prefire fuel loads to mimic naturally occurring fuel-load heterogeneity associated with branch falls, needle fall near large pines, and animal disturbances in a frequently burned longleaf pine (Pinus palustris) savanna in Louisiana, USA. We applied one of four fuel treatments (unaltered control, fine-fuel removal, fine-fuel addition, wood addition) …

Go to article

The Shoot-Specific Expression Of Γ-Glutamylcysteine Synthetase Directs The Long-Distance Transport Of Thiol-Peptides To Roots Conferring Tolerance To Mercury And Arsenic, Yujing Li, Om Parkash Dankher, Laura Carreira, Aaron P. Smith, Richard B. Meagher May 2006

The Shoot-Specific Expression Of Γ-Glutamylcysteine Synthetase Directs The Long-Distance Transport Of Thiol-Peptides To Roots Conferring Tolerance To Mercury And Arsenic, Yujing Li, Om Parkash Dankher, Laura Carreira, Aaron P. Smith, Richard B. Meagher

Faculty Publications

Thiol-peptides synthesized as intermediates in phytochelatin (PC) biosynthesis confer cellular tolerance to toxic elements like arsenic, mercury and cadmium, but little is known about their long-distance transport between plant organs. A modified bacterial γ-glutamylcysteine synthetase (ECS) gene, S1pt::ECS, was expressed in the shoots of the ECS-deficient, heavy-metal-sensitive cad2-1 mutant of Arabidopsis (Arabidopsis thaliana). S1pt::ECS directed strong ECS protein expression in the shoots, but no ECS was detected in the roots of transgenic plant lines. The S1pt::ECS gene restored full mercury tolerance and partial cadmium tolerance to the mutant and enhanced arsenate tolerance significantly beyond wild-type levels. After arsenic treatment, the …

Go to article

Modelling Responses Of Pine Savannas To Climate Change And Large-Scale Disturbance, Brian Beckage, Louis J. Gross, William J. Platt May 2006

Modelling Responses Of Pine Savannas To Climate Change And Large-Scale Disturbance, Brian Beckage, Louis J. Gross, William J. Platt

Faculty Publications

Global warming can potentially influence ecological communities through altered disturbance regimes in addition to increased temperatures. We investigate the response of pine savannas in the southeastern United States to global warming using a simple Lotka-Volterra competition model together with predicted changes to fire and hurricane disturbance regimes with global climate change. In the southeastern United States, decreased frequency of both fires and hurricanes with global warming will shift pine savannas toward a forested state. A CO2 fertilization effect that increases the growth rate of tree populations will also push southeastern landscapes from open savannas towards closed forests. Transient dynamics associated …

Go to article

Natural Disturbances And The Physiognomy Of Pine Savannas: A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet May 2006

Natural Disturbances And The Physiognomy Of Pine Savannas: A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet

Faculty Publications

Question: The decline of the Pinus palustris ecosystems has resulted from anthropogenic influences, such as conversion to pine plantation forestry, agriculture and land development, all of which are closely related to increases in human populations. Other effects, however, have arisen from alterations in disturbance regimes that maintain the structure and function of these ecosystems. How have alterations of the disturbance regime altered the physiognomy of 'old-growth' stands, and what are the implications for ecosystem conservation and restoration? Methods: In contrast to models that emphasize close interactions among the vertically complex strata, we develop a conceptual phenomenological model for the physiognomic …

Go to article

Characterization Of A Branchial Epithelial Calcium Channel (Ecac) In Freshwater Rainbow Trout (Oncorhynchus Mykiss), A. Shahsavarani, B. Mcneill, F. Galvez, C. M. Wood, G. G. Goss, P. P. Hwang, S. F. Perry May 2006

Characterization Of A Branchial Epithelial Calcium Channel (Ecac) In Freshwater Rainbow Trout (Oncorhynchus Mykiss), A. Shahsavarani, B. Mcneill, F. Galvez, C. M. Wood, G. G. Goss, P. P. Hwang, S. F. Perry

Faculty Publications

The entry of calcium (Ca2+) through an apical membrane epithelial calcium channel (ECaC) is thought to a key step in piscine branchial Ca2+ uptake. In mammals, ECaC is a member of the transient receptor potential (TRP) gene family of which two sub-families have been identified, TRPV5 and TPRV6. In the present study we have identified a single rainbow trout (Oncorhynchus mykiss) ECaC (rtECaC) that is similar to the mammalian TRPV5 and TRPV6. Phylogenetic analysis of the protein sequence suggests that an ancestral form of the mammalian genes diverged from those in the lower vertebrates prior to the gene duplication event …

Go to article

Sauria Sines: Novel Short Interspersed Retroposable Elements That Are Widespread In Reptile Genomes, Oliver Piskurek, Christopher C. Austin, Norihiro Okada May 2006

Sauria Sines: Novel Short Interspersed Retroposable Elements That Are Widespread In Reptile Genomes, Oliver Piskurek, Christopher C. Austin, Norihiro Okada

Faculty Publications

SINEs are short interspersed retrotransposable elements that invade new genomic sites. Their retrotransposition depends on reverse transcriptase and endonuclease activities encoded by partner LINEs (long interspersed elements). Recent genomic research has demonstrated that retroposons account for at least 40% of the human genome. Hitherto, more than 30 families of SINEs have been characterized in mammalian genomes, comprising ∼4600 extant species; the distribution and extent of SINEs in reptilian genomes, however, are poorly documented. With more than 7400 species of lizards and snakes, Squamata constitutes the largest and most diverse group of living reptiles. We have discovered and characterized a novel …

Go to article

Phylogenetic And Ecological Determinants Of The Neotropical Dawn Chorus, Karl S. Berg, Robb T. Brumfield, Victor Apanius Apr 2006

Phylogenetic And Ecological Determinants Of The Neotropical Dawn Chorus, Karl S. Berg, Robb T. Brumfield, Victor Apanius

Faculty Publications

The concentration of avian song at first light (i.e. the dawn chorus) is widely appreciated, but has an enigmatic functional significance. One widely accepted explanation is that birds are active at dawn, but light levels are not yet adequate for foraging. In forest communities, the onset to singing should thus be predictable from the species' foraging strata, which is ultimately related to ambient light level. To test this, we collected data from a tropical forest of Ecuador involving 57 species from 27 families of birds. Time of first song was a repeatable, species-specific trait, and the majority of resident birds, …

Go to article

Antagonisms, Mutualisms And Commensalisms Affect Outbreak Dynamics Of The Southern Pine Beetle, Richard W. Hofstetter, James T. Cronin, Kier D. Klepzig, John C. Moser, Matthew P. Ayres Apr 2006

Antagonisms, Mutualisms And Commensalisms Affect Outbreak Dynamics Of The Southern Pine Beetle, Richard W. Hofstetter, James T. Cronin, Kier D. Klepzig, John C. Moser, Matthew P. Ayres

Faculty Publications

Feedback from community interactions involving mutualisms are a rarely explored mechanism for generating complex population dynamics. We examined the effects of two linked mutualisms on the population dynamics of a beetle that exhibits outbreak dynamics. One mutualism involves an obligate association between the bark beetle, Dendroctonus frontalis and two mycangial fungi. The second mutualism involves Tarsonemus mites that are phoretic on D. frontalis ("commensal"), and a blue-staining fungus, Ophiostoma minus. The presence of O. minus reduces beetle larval survival ("antagonistic") by outcompeting beetle-mutualistic fungi within trees yet supports mite populations by acting as a nutritional mutualist. These linked interactions potentially …

Go to article

First Prev Next Last