Digital Commons Network^™

Glycosylphosphatidylinositol-Anchored Proteins Are Required For Cell Wall Synthesis And Morphogenesis In Arabidopsis, C. Stewart Gillmor, Wolfgang Lukowitz, Ginger Brininstool, John C. Sedbrook, Thorsten Hamann, Patricia Poindexter, Chris Somerville

Faculty Publications

Mutations at five loci named PEANUT1-5 (PNT) were identified in a genetic screen for radially swollen embryo mutants, pnt1 cell walls showed decreased crystalline cellulose, increased pectins, and irregular and ectopic deposition of pectins, xyloglucans, and callose. Furthermore, pnt1 pollen is less viable than the wild type, and pnt1 embryos were delayed in morphogenesis and showed defects in shoot and root meristems. The PNT1 gene encodes the Arabidopsis thaliana homolog of mammalian PIG-M, an endoplasmic reticulum-localized mannosyltransferase that is required for synthesis of the glycosylphosphatidylinositol (GPI) anchor. All five pnt mutants showed strongly reduced accumulation of GPI-anchored proteins, suggesting that …

Mutation Of Sac1, An Arabidopsis Sac Domain Phosphoinositide Phosphatase, Causes Alterations In Cell Morphogenesis, Cell Wall Synthesis, And Actin Organization, Ruiqin Zhong, David H. Burk, C. Joseph Nairn, Alicia Wood-Jones, W. Herbert Morrison, Zheng Hua Ye

Faculty Publications

SAC (for suppressor of actin) domain proteins in yeast and animals have been shown to modulate the levels of phosphoinositides, thereby regulating several cellular activities such as signal transduction, actin cytoskeleton organization, and vesicle trafficking. Nine genes encoding SAC domain-containing proteins are present in the Arabidopsis thaliana genome, but their roles in plant cellular functions and plant growth and development have not been characterized. In this report, we demonstrate the essential roles of one of the Arabidopsis SAC domain proteins, AtSAC1, in plant cellular functions. Mutation of the AtSAC1 gene in the fragile fiber7 (fra7) mutant caused a dramatic decrease …

Avian Hosts For West Nile Virus In St. Tammany Parish, Louisiana, 2002, Nicholas Komar, Nicholas A. Panella, Stanley A. Langevin, Aaron C. Brault, Manuel Amador, Eric Edwards, Jennifer C. Owen

Faculty Publications

West Nile virus (WNV) infections in free-ranging birds were studied in Slidell, St. Tammany Parish, Louisiana, after a human encephalitis outbreak peaked there in July 2002. Seroprevalence in resident, free-ranging wild birds in one suburban site was 25% and 24% in August and October, respectively, indicating that most transmission had ceased by early August. Mortality rates, seroprevalence rates, host competence, and crude population estimates were used in mathematical models to predict actual infection rates, population impacts, and importance as amplifying hosts for several common passerine birds. Northern cardinal (Cardinalis cardinalis) and house sparrow (Passer domesticus) were the principal amplifying hosts, …

Applications Of Phylogenetics To Issues In Freshwater Crayfish Biology, Keith A. Crandall

Faculty Publications

Freshwater crayfish have served as model organisms for over 125 years in scientific research, from areas such as neurobiology and vision research to conservation biology and evolution. Recently, evolutionary histories in the form of phylogenies have served as a critical foundation for testing hypotheses in such diverse research areas as well. In this article, I review the amazing diversity of freshwater crayfish, especially in a phylogenetic context and explore how these evolutionary histories have informed crayfish biology and can be used powerfully in the future to guide research in a diversity of areas. Throughout the article, I draw on examples …

Detection Of Homocysteine And Cysteine, Weihua Wang, Oleksandr Rusin, Xiangyang Xu, Kyu Kwang Kim, Jorge O. Escobedo, Sayo O. Fakayode, Kristin A. Fletcher, Mark Lowry, Corin M. Schowalter, Candace M. Lawrence, Frank R. Fronczek, Isiah M. Warner, Robert M. Strongin

Faculty Publications

At elevated levels, homocysteine (Hcy, 1) is a risk factor for cardiovascular diseases, Alzheimer's disease, neural tube defects, and osteoporosis. Both 1 and cysteine (Cys, 3) are linked to neurotoxicity. The biochemical mechanisms by which 1 and 3 are involved in disease states are relatively unclear. Herein, we describe simple methods for detecting either Hey or Cys in the visible spectral region with the highest selectivity reported to date without using biochemical techniques or preparative separations. Simple methods and readily available reagents allow for the detection of Cys and Hey in the range of their physiologically relevant levels. New HPLC …

Host-Parasitoid Spatial Ecology: A Plea For A Landscape-Level Synthesis, James T. Cronin, John D. Reeve

Faculty Publications

A growing body of literature points to a large-scale research approach as essential for understanding population and community ecology. Many of our advances regarding the spatial ecology of predators and prey can be attributed to research with insect parasitoids and their hosts. In this review, we focus on the progress that has been made in the study of the movement and population dynamics of hosts and their parasitoids in heterogeneous landscapes, and how this research approach may be beneficial to pest management programs. To date, few studies have quantified prey and predator rates and ranges of dispersal and population dynamics …

Successful Island Reintroductions Of New Zealand Robins And Saddlebacks With Small Numbers Of Founders, Sabrina S. Taylor, Ian G. Jamieson, Doug P. Armstrong

Faculty Publications

Populations established with a small number of founders are thought to have a high risk of extinction due to Allee effects, demographic stochasticity, inbreeding and reduced genetic variation. We tested whether the initial number of birds released was related to persistence in reintroductions of saddlebacks (Philesturnus carunculatus) and robins (Petroica australis) to New Zealand offshore islands. Data were analysed for 31 populations that had been observed for at least 3 years since reintroductions. The numbers released ranged from 5-188. Most of the populations (26) survived and grew, including five from less than 15 founders, and four out of the five …

Influences Of Dietary Soy Isoflavones On Metabolism But Not Nociception And Stress Hormone Responses In Ovariectomized Female Rats, Edwin D. Lephart, Lihong H. Bu, Kenneth Setchell

Faculty Publications

Isoflavones, the most abundant phytoestrogens in soy foods, are structurally similar to 17beta-estradiol. Few studies have examined the nociception and stress hormone responses after consumption of soy isoflavones. Methods: In this study, ovariectomized (OVX) female Long-Evans rats were fed either an isoflavone-rich diet (Phyto-600) or an isoflavone-free diet (Phyto-free). We examined the effects of soy isoflavones on metabolism by measuring body weights, food/water intake, adipose tissue weights as well as serum leptin levels. Also, circulating isoflavone levels were quantified. During chemically induced estrous, nociceptive thresholds were recorded. Then, the animals were subjected to a stressor and stress hormone levels were …

Genetic Analysis Of The Sars-Coronavirus Spike Glycoprotein Functional Domains Involved In Cell-Surface Expression And Cell-To-Cell Fusion, Chad M. Petit, Jeffrey M. Melancon, Vladimir N. Chouljenko, Robin Colgrove, Michael Farzan, David M. Knipe, K. G. Kousoulas

Faculty Publications

The SARS-coronavirus (SARS-CoV) is the etiological agent of severe acute respiratory syndrome (SARS). The SARS-CoV spike (S) glycoprotein mediates membrane fusion events during virus entry and virus-induced cell-to-cell fusion. To delineate functional domains of the SARS-CoV S glycoprotein, single point mutations, cluster-to-lysine and cluster-to-alanine mutations, as well as carboxyl-terminal truncations were investigated in transient expression experiments. Mutagenesis of either the coiled-coil domain of the S glycoprotein amino terminal heptad repeat, the predicted fusion peptide, or an adjacent but distinct region, severely compromised S-mediated cell-to-cell fusion, while intracellular transport and cell-surface expression were not adversely affected. Surprisingly, a carboxyl-terminal truncation of …

Immunocytochemical Localization Of Small-Conductance, Calcium-Dependent Potassium Channels In Astrocytes Of The Rat Supraoptic Nucleus, William E. Armstrong, Adam Rubrum, Ryoichi Teruyama, Chris T. Bond, John P. Adelman

Faculty Publications

Supraoptic nucleus (SON) neurons possess a prominent afterhyperpolarization (AHP) that contributes to spike patterning. This AHP is probably underlain by a small-conductance, CA2+-dependent, K+ type 3 (SK3) channel. To determine the distribution of SK3 channels within the SON, we used immunocytochemistry in rats and in transgenic mice with a regulatory cassette on the SK3 gene, allowing regulated expression with dietary doxycycline (DOX). In rats and wild-type mice, SK3 immunostaining revealed an intense lacy network surrounding SON neurons, with weak staining in neuronal somata and dendrites. In untreated, conditional SK3 knockout mice, SK3 was overexpressed, but the pericellular pattern in the …

A Role For Airway Remodeling During Respiratory Syncytial Virus Infection, David Becnel, Dahui You, Joshua Erskin, Dawn M. Dimina, Stephania A. Cormier

Faculty Publications

Background: Severe respiratory syncytial virus infection (RSV) during infancy has been shown to be a major risk factor for the development of subsequent wheeze. However, the reasons for this link remain unclear. The objective of this research was to determine the consequences of early exposure to RSV and allergen in the development of subsequent airway hyperreactivity (AHR) using a developmental time point in the mouse that parallels that of the human neonate. Methods: Weanling mice were sensitized and challeged with ovalbumin (Ova) and/or infected with RSV. Eight days after the last allergen challenge, various pathophysiological endpoints were examined. Results: AHR …

Analysis Of Gaits For A Rotating Tripedal Robot, Damian M. Lyons, Kiran Pamnany

Faculty Publications

A goal of robotics has been to develop mechanisms that have the efficiency and speed of wheeled robots with the terrain flexibility of legged robots. In previous work, we have proposed a unique three-legged mechanism, the rotopod, designed to integrate these two useful approaches to locomotion. In this paper, we present an analysis of the variety of gaits that can be exhibited by the rotopod. We present examples of many of these gaits and discuss their potential use. A trajectory generation algorithm is presented that can be used to generate point to point trajectories using one of three different styles …

Prediction Of Sediment-Bound Nutrient Delivery From Semi-Arid California Watersheds, Emmanuel Gabet, Noah Fierer, Oliver Chadwick

Faculty Publications

Soil carbon (C), nitrogen (N), and phosphorus (P) are lost from hillslopes in particulate forms through soil erosion. The fate of the eroded C (e.g., sequestration or oxidation) may affect the global C budget, and delivery of N and P to waterbodies can lead to eutrophication. Whereas the magnitude of particulate nutrient losses may be similar to or greater than dissolved losses, it is rarely estimated. We couple a sediment delivery model with measurements of C, N, and P in soil to account explicitly for hillslope sediment transport processes that yield sediment-bound nutrients to fluvial networks. The model is applied …

Watson Brake, A Middle Archaic Mound Complex In Northeast Louisiana, Joe W. Saunders, Rolfe D. Mandel, C. Garth Sampson, Charles M. Allen, E. Thurman Allen, Daniel A. Bush, James K. Feathers, Kristen J. Gremillion, C.T. Hallmark, H. Edwin Jackson, Jay K. Johnson, Reca Jones, Roger T. Saucier, Gary L. Stringer, Malcolm F. Vidrine

Faculty Publications

Middle Archaic earthen mound complexes in the lower Mississippi valley are remote antecedents of the famous but much younger Poverty Point earthworks. Watson Brake is the largest and most complex of these early mound sites. Wry extensive coring and stratigraphic studies, aided by 25 radiocarbon dates and six huninescence dates, show that minor earthworks were begun here at ca. 3500 B.C. in association with an oval arrangement of burned rock middens at the edge of a stream terrace. The full extent of the first earthworks is not yet known. Substantial moundraising began ca. 3350 B.C. and continued in stages until …

Is Adventist Theology Compatible With Evolutionary Theory?, Fernando L. Canale

Faculty Publications

No abstract provided.

Hurricane-Forced Upwelling And Chlorophyll A Enhancement Within Cold-Core Cyclones In The Gulf Of Mexico, Nan D. Walker, Robert R. Leben, Shreekanth Balasubramanian

Faculty Publications

Clear skies, subsequent to Hurricane Ivan's passage across the Gulf of Mexico in September 2004, provided a unique opportunity to investigate upper ocean responses to a major hurricane. Oceanic cyclonic circulation was rapidly intensified by the hurricane's wind field (59-62 m s^-1), maximizing upwelling and surface cooling (3-7°C) in two large areas along Ivan's track. Upward isothermal displacements of 50-65 m, computed from wind stress and sea surface height changes, caused rapid ventilation of thermoclines and nutriclines, leading to phytoplankton blooms with peak concentrations 3-4 days later. Wind speed changes along Ivan's track demonstrated that the cool waters …

The Emergence Of The Social Brain Network: Evidence From Typical And Atypical Development, Mark H. Johnson, Richard Griffin, Gergely Csibra, Hanife Halit, Teresa Farroni, Michelle Dehaan, Leslie A. Tucker, Simon Baron-Cohen, John E. Richards

Faculty Publications

Several research groups have identified a network of regions of the adult cortex that are activated during social perception and cognition tasks. In this paper we focus on the development of components of this social brain network during early childhood and test aspects of a particular viewpoint on human functional brain development: “interactive specialization.” Specifically, we apply new data analysis techniques to a previously published data set of event-related potential ~ERP! studies involving 3-, 4-, and 12-month-old infants viewing faces of different orientation and direction of eye gaze. Using source separation and localization methods, several likely generators of scalp recorded …

A Climate-Based Approach To The Restoration Of Fire-Dependent Ecosystems, Brian Beckage, William J. Platt, Bob Panko

Faculty Publications

Recurrent fires are integral to the function of many ecosystems worldwide. The management of fire-frequented ecosystems requires the application of fire at the appropriate frequency and seasonally, but establishing the natural fire regime for an ecosystem can be problematic. Historical records of fires are often not available, and surrogates for past fires may not exist. We suggest that the relationship between climate and fire can provide an alternative means for inferring past fire regimes in some ecosystems. © 2005 Society for Ecological Restoration International.

Status, Trends And Management Of Sturgeon And Paddlefish Fisheries, Ellen K. Pikitch, Phaedra Doukakis, Liz Lauck, Prosanta Chakrabarty, Daniel L. Erickson

Faculty Publications

The 27 extant species of sturgeons and paddlefishes (Order Acipenseriformes) represent a unique and relict lineage of fishes. Producers of coveted black caviar, sturgeons are one of the most valuable wildlife commodities on earth. The group is among the most endangered fishes with all species listed under Convention on International Trade in Endangered Species (CITES) Appendix I (two species) or II (25 species), only two species considered Lower Risk by IUCN, four of the nine US taxa and one Caspian species protected under the Endangered Species Act, and local extinctions recorded for 19 of 27 species. Despite their well-publicized imperilled …

Easy's Gettin' Harder All The Time: The Computational Theory And Affective States, Jason Megill, Jon Cogburn

Faculty Publications

We argue that A. Damasio's (1994) Somatic Marker hypothesis can explain why humans don't generally suffer from the frame problem, arguably the greatest obstacle facing the Computational Theory of Mind. This involves showing how humans with damaged emotional centers are best understood as actually suffering from the frame problem. We are then able to show that, paradoxically, these results provide evidence for the Computational Theory of Mind, and in addition call into question the very distinction between easy and hard problems in the contemporary philosophy of mind. © Blackwell Publishing Ltd. 2005.

Paradox And The Consumption Of Authenticity Through Reality Television, Randall L. Rose, Stacy L. Wood

Faculty Publications

We position reality television within the broader category of consumer practices of authenticity seeking in a postmodern cultural context. The study draws on relevant perspectives from consumer research, literary criticism, sociology, and anthropology to argue that viewers of reality television encounter three elements of paradox in the process of constructing authenticity. The negotiation of each paradox exceeds the process of coping with or resolving their inherent contradictions to encompass the creation of new values. We argue that consumers blend fantastic elements of programming with indexical elements connected to their lived experiences to create a form of self-referential hyperauthenticity.

Soy Isoflavone Glycitein Protects Against Beta Amyloid-Induced Toxicity And Oxidative Stress In Transgenic Caenorhabditis Elegans, Astrid Gutierrez-Zepeda, Ross Santell, Zhixin Wu, Marishka Brown, Yanjue Wu, Ikhlas Khan, Christopher D. Link, Baolu Zhao, Yuan Luo

Faculty Publications

Background

Epidemiological studies have associated estrogen replacement therapy with a lower risk of developing Alzheimer's disease, but a higher risk of developing breast cancer and certain cardiovascular disorders. The neuroprotective effect of estrogen prompted us to determine potential therapeutic impact of soy-derived estrogenic compounds. Transgenic C. elegans, that express human beta amyloid (Aβ), were fed with soy derived isoflavones genistein, daidzein and glycitein (100 μg/ml) and then examined for Aβ-induced paralysis and the levels of reactive oxygen species.

Results

Among the three compounds tested, only glycitein alleviated Aβ expression-induced paralysis in the transgenic C. elegans. This activity of …

Animal Virus Replication And Rnai-Mediated Antiviral Silencing In Caenorhabditis Elegans, R. Lu, M. Maduro, F. Li, H. W. Li, G. Broitman-Maduro, W. X. Li, S. W. Ding

Faculty Publications

The worm Caenorhabditis elegans is a model system for studying many aspects of biology, including host responses to bacterial pathogens, but it is not known to support replication of any virus. Plants and insects encode multiple Dicer enzymes that recognize distinct precursors of small RNAs and may act cooperatively. However, it is not known whether the single Dicer of worms and mammals is able to initiate the small RNA-guided RNA interference (RNAi) antiviral immunity as occurs in plants and insects. Here we show complete replication of the Flock house virus (FHV) bipartite, plus-strand RNA genome in C. elegans. We show …

Altering The Tropism Of Lentiviral Vectors Through Pseudotyping, James Cronin, Xian Yang Zhang, Jakob Reiser

Faculty Publications

The host range of retroviral vectors including lentiviral vectors can be expanded or altered by a process known as pseudotyping. Pseudotyped lentiviral vectors consist of vector particles bearing glycoproteins (GPs) derived from other enveloped viruses. Such particles possess the tropism of the virus from which the GP was derived. For example, to exploit the natural neural tropism of rabies virus, vectors designed to target the central nervous system have been pseudotyped using rabies virus-derived GPs. Among the first and still most widely used GPs for pseudotyping lentiviral vectors is the vesicular stomatitis virus GP (VSV-G), due to the very broad …

Extraocular Muscle Activity, Rapid Eye Movements And The Development Of Active And Quiet Sleep, Adele M. H. Seelke, Andrew J. Gall, Karl Æ. Karlsson, Mark S. Blumberg

Faculty Publications

Rapid eye movements (REMs), traditionally measured using the electrooculogram (EOG), help to characterize active sleep in adults. In early infancy, however, they are not clearly expressed. Here we measured extraocular muscle activity in infant rats at 3 days of age (P3), P8 and P14-15 in order to assess the ontogeny of REMs and their relationship with other forms of sleep-related phasic activity. We found that the causal relationship between extraocular muscle twitches and REMs strengthened during the first two postnatal weeks, reflecting increased control of the extraocular muscles over eye movements. As early as P3, however, phasic bursts of extraocular …

Enhancement Of Calcium-Dependent Afterpotentials In Oxytocin Neurons Of The Rat Supraoptic Nucleus During Lactation, Ryoichi Teruyama, William E. Armstrong

Faculty Publications

The firing pattern of oxytocin (OT) hormone synthesizing neurons changes dramatically immediately before each milk ejection, when a brief burst of action potentials is discharged. OT neurons possess intrinsic currents that would modulate this burst. Our previous studies showed the amplitude of the Ca2+-dependent afterhyperpolarization (AHP) following spike trains is significantly larger during lactation. In the present study we sought to determine which component of the AHP is enhanced, and whether the enhancement could be related to changes in whole-cell Ca2+ current or the Ca2+ transient in identified OT or vasopressin (VP) neurons during lactation. We confirmed, with whole-cell current-clamp …

The 'Abuse Excuse' In Capital Sentencing Trials: Is It Relevant To Responsibility, Punishment, Or Neither?, Paul J. Litton

Faculty Publications

The violent criminal who was a victim of severe childhood abuse frequently appears in the responsibility literature because he presents a difficulty for theorists who maintain the compatibility of causal determinism and our practices of holding persons responsible. The challenge is based on the fact that learning about an offender's horrific childhood mitigates the indignation that many persons feel towards him, possibly indicating that they hold him less than fully responsible. Many capital defendants present evidence of suffering childhood abuse, and many jurors find this evidence to count against imposing death. The most obvious explanation for a response like this …

V-Atpase Expression During Development Of Artemia Franciscana Embryos: Potential Role For Proton Gradients In Anoxia Signaling, Joseph A. Covi, Steven C. Hand

Faculty Publications

Under anoxia, Artemia franciscana embryos downregulate metabolic processes and approach an ametabolic state. Entrance into this quiescent state is accompanied by a profound acidification of the intracellular space, and more than two decades of research now clearly demonstrates that this acidification is critical to metabolic downregulation in anoxic embryos. However, the proximal mechanisms responsible for the pH shift remain largely unidentified. Here, we report evidence demonstrating expression of the V-ATPase in encysted embryos and present an argument for its involvement in the intracellular acidification induced by anoxia. We identified a single B-subunit cDNA sharing the greatest degree of sequence similarity …

V-Atpase Inhibition Prevents Recovery From Anoxia In Artemia Franciscana Embryos: Quiescence Signaling Through Dissipation Of Proton Gradients, Joseph A. Covi, W. Dale Treleaven, Steven C. Hand

Faculty Publications

The metabolic downregulation critical for long-term survival of Artemia franciscana embryos under anoxia is mediated, in part, by a progressive intracellular acidification. However, very little is known about the mechanisms responsible for the pH transitions associated with exposure to, and recovery from, oxygen deprivation. In the present study, we demonstrate with 31P-NMR that incubation of intact embryos with the V-ATPase inhibitor bafilomycin A1 severely limits intracellular alkalinization during recovery from anoxia without affecting the restoration of cellular nucleotide triphosphate levels. Based on these data, it appears that oxidative phosphorylation and ATP resynthesis can only account for the first 0.3 pH …

The Regulation Of Fatty Acid Synthase By Stat5a, Jessica C. Hogan, Jacqueline M. Stephens

Faculty Publications

Growth hormone (GH) diminishes adipose tissue mass in vivo and decreases expression and activity of fatty acid synthase (FAS) in adipocytes. GH and prolactin (PRL) are potent activators of STAT5 and exert adipogenic and antiadipogenic effects in adipocytes. In this study, we demonstrate that GH and PRL decrease the mRNA and protein levels of FAS in 3T3-L1 adipocytes. We present evidence that indicates that FAS is repressed at the level of transcription. In addition, PRL responsiveness was shown to exist between -1,594 and -700 of the rat FAS promoter. Moreover, responsiveness to PRL was abolished with mutation of a site …