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Biological Sciences Faculty Publications

Series

2003

Articles 1 - 29 of 29

Full-Text Articles in Life Sciences

Thermodynamic Characterization Of The Binding Of Activator Of G Protein Signaling 3 (Ags3) And Peptides Derived From Ags3 With G Alpha I1, Anirban Adhikari, Stephen R. Sprang Dec 2003

Thermodynamic Characterization Of The Binding Of Activator Of G Protein Signaling 3 (Ags3) And Peptides Derived From Ags3 With G Alpha I1, Anirban Adhikari, Stephen R. Sprang

Biological Sciences Faculty Publications

Activator of G protein signaling 3 (AGS3) is a guanine nucleotide dissociation inhibitor (GDI) that contains four G protein regulatory (GPR) or GoLoco motifs in its C-terminal domain. The entire C-terminal domain (AGS3-C) as well as certain peptides corresponding to individual GPR motifs of AGS3 bound to G alpha i1 and inhibited the binding of GTP by stabilizing the GDP-bound conformation of G alpha i1. The stoichiometry, free energy, enthalpy, and dissociation constant for binding of AGS3-C to G alpha i1 were determined using isothermal titration calorimetry. AGS3-C possesses two apparent high affinity (Kd approximately 20 nm) and two apparent …

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Mitogenic Effect Of Bartonella Bacilliformis On Human Vascular Endothelial Cells And Involvement Of Groel, Michael F. Minnick, Laura S. Smitherman, D. Scott Samuels Dec 2003

Mitogenic Effect Of Bartonella Bacilliformis On Human Vascular Endothelial Cells And Involvement Of Groel, Michael F. Minnick, Laura S. Smitherman, D. Scott Samuels

Biological Sciences Faculty Publications

Bartonellae are bacterial pathogens for a wide variety of mammals. In humans, bartonellosis can result in angioproliferative lesions that are potentially life threatening to the patient, including bacillary angiomatosis, bacillary peliosis, and verruga peruana. The results of this study show that Bartonella bacilliformis, the agent of Oroya fever and verruga peruana, produces a proteinaceous mitogen for human vascular endothelial cells (HUVECs) that acts in a dose-dependent fashion in vitro with maximal activity at >72 h of exposure and results in a 6- to 20-fold increase in cell numbers relative to controls. The mitogen increases bromodeoxyuridine (BrdU) incorporation into HUVECs …

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Aada Confers Streptomycin Resistance In Borrelia Burgdorferi, Kristi L. Frank, Sharyl F. Bundle, Michele E. Kresge, Christian H. Eggers, D. Scott Samuels Nov 2003

Aada Confers Streptomycin Resistance In Borrelia Burgdorferi, Kristi L. Frank, Sharyl F. Bundle, Michele E. Kresge, Christian H. Eggers, D. Scott Samuels

Biological Sciences Faculty Publications

To enhance genetic manipulation of the Lyme disease spirochete Borrelia burgdorferi, we assayed the aadA gene for the ability to confer resistance to the antibiotics spectinomycin and streptomycin. Using the previously described pBSV2 as a backbone, a shuttle vector, termed pKFSS1, which carries the aadA open reading frame fused to the B. burgdorferi flgB promoter was constructed. The hybrid flgB promoter-aadA cassette confers resistance to spectinomycin and streptomycin in both B. burgdorferi and Escherichia coli. pKFSS1 has a replication origin derived from the 9-kb circular plasmid and can be comaintained in B. burgdorferi with extant shuttle vector pCE320, which has …

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Evolution Of Avian Locomotion: Correlates Of Flight Style, Locomotor Modules, Nesting Biology, Body Size, Development, And The Origin Of Flapping Flight, Kenneth P. Dial Oct 2003

Evolution Of Avian Locomotion: Correlates Of Flight Style, Locomotor Modules, Nesting Biology, Body Size, Development, And The Origin Of Flapping Flight, Kenneth P. Dial

Biological Sciences Faculty Publications

No abstract provided.

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Differences In Hyporheic-Zone Microbial Community Structure Along A Heavy-Metal Contamination Gradient, Kevin P. Feris, Philip W. Ramsey, Frazar Chris, Johnnie N. Moore, James E. Gannon, William E. Holben Sep 2003

Differences In Hyporheic-Zone Microbial Community Structure Along A Heavy-Metal Contamination Gradient, Kevin P. Feris, Philip W. Ramsey, Frazar Chris, Johnnie N. Moore, James E. Gannon, William E. Holben

Biological Sciences Faculty Publications

Heavy metals contaminate numerous freshwater streams and rivers worldwide. Previous work by this group demonstrated a relationship between the structure of hyporheic microbial communities and the fluvial deposition of heavy metals along a contamination gradient during the fall season. Seasonal variation has been documented in microbial communities in numerous terrestrial and aquatic environments, including the hyporheic zone. The current study was designed to assess whether relationships between hyporheic microbial community structure and heavy-metal contamination vary seasonally by monitoring community structure along a heavy-metal contamination gradient for more than a year. No relationship between total bacterial abundance and heavy metals was …

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Selective Plating Underestimates Abundance And Shows Differential Recovery Of Bifidobacterial Species From Human Feces, Juha H. A. Apajalahti, Anu Kettunen, Päivi H. Nurminen, Hanna Jatila, William E. Holben Sep 2003

Selective Plating Underestimates Abundance And Shows Differential Recovery Of Bifidobacterial Species From Human Feces, Juha H. A. Apajalahti, Anu Kettunen, Päivi H. Nurminen, Hanna Jatila, William E. Holben

Biological Sciences Faculty Publications

The aim of the present work was to compare the efficacies and levels of selectivity of different culture-dependent and -independent methods for analyzing bifidobacteria in human stool samples. The three different culture media used here significantly differed from each other, particularly with regard to the recovery of Bifidobacterium adolescentis. Bifidobacterium medium failed to recover B. adolescentis; Beerens medium recovered some B. adolescentis organisms (17% of total bifidobacteria), whereas tomato-Eugon medium recovered mainly B. adolescentis organisms (58% of total bifidobacteria). A culture-independent method that combines GC fractionation of bacterial community DNA and 16S rRNA sequencing indicated that B. adolescentis organisms accounted …

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Monitoring Immediate-Early Gene Expression Through Firefly Luciferase Imaging Of Hrs/J Hairless Mice, Michael E. Geusz, Anne M. Collaco Aug 2003

Monitoring Immediate-Early Gene Expression Through Firefly Luciferase Imaging Of Hrs/J Hairless Mice, Michael E. Geusz, Anne M. Collaco

Biological Sciences Faculty Publications

Background: Gene promoters fused to the firefly luciferase gene (luc) are useful for examining gene regulation in live transgenic mice and they provide unique views of functioning organs. The dynamics of gene expression in cells and tissues expressing luciferase can be observed by imaging this enzyme's bioluminescent oxidation of luciferin. Neural pathways involved in specific behaviors have been identified by localizing expression of immediate-early genes such as c-fos. A transgenic mouse line with luc controlled by the human c-fos promoter (fos::luc) has enabled gene expression imaging in brain slice cultures. To optimize imaging of immediate-early gene expression throughout intact mice, …

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A Structural Linkage Between The Dimerization And Encapsidation Signals In Hiv-2 Leader Rna, J. M. Lanchy, J. D. Ivanovitch, J. Stephen Lodmell Aug 2003

A Structural Linkage Between The Dimerization And Encapsidation Signals In Hiv-2 Leader Rna, J. M. Lanchy, J. D. Ivanovitch, J. Stephen Lodmell

Biological Sciences Faculty Publications

The 5' untranslated leader region of retroviral RNAs contains noncoding information that is essential for viral replication, including signals for transcriptional transactivation, splicing, primer binding for reverse transcription, dimerization of the genomic RNA, and encapsidation of the viral RNA into virions. These RNA motifs have considerable structural and functional overlap. in this study, we investigate the conformational dynamics associated with the use and silencing of a sequence in HIV-2 RNA that is involved in genomic RNA dimerization called stem-loop 1 (SL1) and its relationship with a flanking sequence that is known to be important for encapsidation of viral RNAs. We …

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Ribosomal Localization Of Translation Initiation Factor If2, Stefano Marzi, William Knight, Letizia Brandi, Enrico Caserta, Natalia Soboleva, Walter E. Hill, Claudio O. Gualerzi, J. Stephen Lodmell Aug 2003

Ribosomal Localization Of Translation Initiation Factor If2, Stefano Marzi, William Knight, Letizia Brandi, Enrico Caserta, Natalia Soboleva, Walter E. Hill, Claudio O. Gualerzi, J. Stephen Lodmell

Biological Sciences Faculty Publications

Bacterial translation initiation factor IF2 is a GTP-binding protein that catalyzes binding of initiator fMet-tRNA in the ribosomal P site. The topographical localization of IF2 on the ribosomal subunits, a prerequisite for understanding the mechanism of initiation complex formation, has remained elusive. Here, we present a model for the positioning of IF2 in the 70S initiation complex as determined by cleavage of rRNA by the chemical nucleases Cu(II):1,10-orthophenanthroline and Fe(II):EDTA tethered to cysteine residues introduced into IF2. Two specific amino acids in the GII domain of IF2 are in proximity to helices H3, H4, H17, and H18 of 16S rRNA. …

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River Flows And Water Wars: Emerging Science For Environmental Decision Making, N. Leroy Poff, J. David Allan, Margaret A. Palmer, David D. Hart, Brian D. Richter, Angela H. Arthington, Kevin H. Rogers, Judy L. Meyer, Jack Arthur Stanford Aug 2003

River Flows And Water Wars: Emerging Science For Environmental Decision Making, N. Leroy Poff, J. David Allan, Margaret A. Palmer, David D. Hart, Brian D. Richter, Angela H. Arthington, Kevin H. Rogers, Judy L. Meyer, Jack Arthur Stanford

Biological Sciences Faculty Publications

Real and apparent conflicts between ecosystem and human needs for fresh water are contributing to the emergence of an alternative model for conducting river science around the world. The core of this new paradigm emphasizes the need to forge new partnerships between scientists and other stakeholders where shared ecological goals and river visions are developed, and the need for new experimental approaches to advance scientific understanding at the scales relevant to whole-river management. We identify four key elements required to make this model succeed: existing and planned water projects represent opportunities to conduct ecosystem-scale experiments through controlled river flow manipulations; …

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Effect Of Phosphorus Amendments On Present Day Plankton Communities In Pelagic Lake Erie, Steven W. Wilhelm, Jennifer M. Debruyn, Osnat Gillor, Michael R. Twiss, Kasey Livingston, Richard A. Bourbonniere, Lisa D. Pickell, Charles G. Trick, Amanda L. Dean, Robert Michael Mckay Jul 2003

Effect Of Phosphorus Amendments On Present Day Plankton Communities In Pelagic Lake Erie, Steven W. Wilhelm, Jennifer M. Debruyn, Osnat Gillor, Michael R. Twiss, Kasey Livingston, Richard A. Bourbonniere, Lisa D. Pickell, Charles G. Trick, Amanda L. Dean, Robert Michael Mckay

Biological Sciences Faculty Publications

To address questions regarding the potential impact of elevated total phosphorus (TP) inputs (due to relaxed regulations of TP loading), a series of TP enrichment experiments were conducted at pelagic stations in the 3 hydrologically distinct basins of Lake Erie. Results of nutrient assimilation measurements and assays for nutrient bioavailability suggest that the chemical speciation, and not concentration, of nitrogenous compounds may influence phytoplankton community structure; this in turn may lead to the selective proliferation of cyanobacteria in the eastern basin of the lake. Assays with cyanobacterial bioluminescent reporter systems for P and N availability as well as N-tot:P-tot assimilation …

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Differences In Cottonwood Growth Between A Losing And A Gaining Reach Of An Alluvial Floodplain, Mary J. Harner, Jack Arthur Stanford Jun 2003

Differences In Cottonwood Growth Between A Losing And A Gaining Reach Of An Alluvial Floodplain, Mary J. Harner, Jack Arthur Stanford

Biological Sciences Faculty Publications

Interstitial flow of river (hyporheic) water influences algal productivity, benthic assemblages, and locations of fish spawning. However, little is known of the effects of hyporheic flow on the growth of riparian vegetation. By increasing water availability and nutrient delivery, regional upwelling of hyporheic water may increase the growth of terrestrial vegetation. We tested and accepted the hypothesis that cottonwood trees (Populus trichocarpa) in a gaining reach of an alluvial floodplain grow faster than trees in a losing reach by comparing basal areas and ages on an expansive floodplain in western Montana (USA). Trees in the gaining reach had …

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Phenotypic Plasticity And Interactions Among Plants, Ragan M. Callaway, Steven C. Pennings, Christina L. Richards May 2003

Phenotypic Plasticity And Interactions Among Plants, Ragan M. Callaway, Steven C. Pennings, Christina L. Richards

Biological Sciences Faculty Publications

We know a great deal about the plastic responses of plant phenotypes to the abiotic and biotic environment, but very little about the consequences of phenotypic plasticity for plant communities. In other words, we know that plant traits can vary widely for a given genotype, but we know little about the importance of trait-mediated interactions (TMI) among plants. Here, we discuss three major factors that affect the expression of phenotypic plasticity: variation in the abiotic environment, variation in the presence or identity of neighbors, and variation in herbivory. We consider how plastic responses to these factors might affect interactions among …

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Differential Expression Of The Invasion-Associated Locus B (Ialb) Gene Of Bartonella Bacilliformis In Response To Environmental Cues, Sherry A. Coleman, Michael F. Minnick Apr 2003

Differential Expression Of The Invasion-Associated Locus B (Ialb) Gene Of Bartonella Bacilliformis In Response To Environmental Cues, Sherry A. Coleman, Michael F. Minnick

Biological Sciences Faculty Publications

Bartonella bacilliformis is the causative agent of the biphasic human disease, Oroya fever. During the primary disease phase, up to 100% of the circulating erythrocytes can be parasitized and 80% lysed. During the secondary phase of this disease, bacterial invasion shifts to endothelial cells lining the vasculature. B. bacilliformis is transferred between human hosts by the sandfly, Lutzomyia verrucarum. To investigate the regulation of ialB by environmental cues signaling vector-to-host transmission; nuclease protection assays were performed to compare the amount of ialB mRNA in bacteria subjected to temperature shift, pH change, oxidative stress, or hemin limitation. The amount of ialB …

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Mapping The Galpha13 Binding Interface Of The Rgrgs Domain Of P115rhogef, Zhe Chen, William D. Singer, Clark D. Wells, Stephen R. Sprang, Paul C. Sternweis Mar 2003

Mapping The Galpha13 Binding Interface Of The Rgrgs Domain Of P115rhogef, Zhe Chen, William D. Singer, Clark D. Wells, Stephen R. Sprang, Paul C. Sternweis

Biological Sciences Faculty Publications

Structural requirements for function of the Rho GEF (guanine nucleotide exchange factor) regulator of G protein signaling (rgRGS) domains of p115RhoGEF and homologous exchange factors differ from those of the classical RGS domains. An extensive mutagenesis analysis of the p115RhoGEF rgRGS domain was undertaken to determine its functional interface with the Galpha(13) subunit. Results indicate that there is global resemblance between the interaction surface of the rgRGS domain with Galpha(13) and the interactions of RGS4 and RGS9 with their Galpha substrates. However, there are distinct differences in the distribution of functionally critical residues between these structurally similar surfaces and an …

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Energetic Adaptations Along A Broad Latitudinal Gradient: Implications For Widely Distributed Assemblages, Jeffrey Gibson Miner, James E. Garvey, Dennis R. Devries, Russell A. Wright Feb 2003

Energetic Adaptations Along A Broad Latitudinal Gradient: Implications For Widely Distributed Assemblages, Jeffrey Gibson Miner, James E. Garvey, Dennis R. Devries, Russell A. Wright

Biological Sciences Faculty Publications

Most community-based models in ecology assume that all individuals within a species respond similarly to environmental conditions and thereby exert identical effects as consumers or prey. Rather, individuals differ among systems, with important implications for population demographics and community interactions. For widely distributed assemblages made up of poikilotherms with high first-year mortality, species-specific differences in growth reaction norms as affected by both temperature and genotype will influence biotic interactions. For a broadly distributed fish assemblage, first-year growth does not vary with latitude for a planktivorous prey species, but declines with increasing latitude for a terminal piscivore. Size-based competitive interactions between …

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Five-Member Gene Family Of Bartonella Quintana, Michael F. Minnick, Kate N. Sappington, Laura S. Smitherman, Siv G. E. Andersson, Olof Karlberg, James A. Carroll Feb 2003

Five-Member Gene Family Of Bartonella Quintana, Michael F. Minnick, Kate N. Sappington, Laura S. Smitherman, Siv G. E. Andersson, Olof Karlberg, James A. Carroll

Biological Sciences Faculty Publications

Bartonella quintana, the agent of trench fever and an etiologic agent of bacillary angiomatosis, has an extraordinarily high hemin requirement for growth compared to other bacterial pathogens. We previously identified the major hemin receptor of the pathogen as a 30-kDa surface protein, termed HbpA. This report describes four additional homologues that share approximately 48% amino acid sequence identity with hbpA. Three of the genes form a paralagous cluster, termed hbpCAB, whereas the other members, hbpD and hbpE, are unlinked. Secondary structure predictions and other evidence suggest that Hbp family members are beta-barrels located in the outer membrane and contain eight …

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Wing-Assisted Incline Running And The Evolution Of Flight, Kenneth P. Dial Jan 2003

Wing-Assisted Incline Running And The Evolution Of Flight, Kenneth P. Dial

Biological Sciences Faculty Publications

Flapping wings of galliform birds are routinely used to produce aerodynamic forces oriented toward the substrate to enhance hindlimb traction. Here, I document this behavior in natural and laboratory settings. Adult birds fully capable of aerial flight preferentially employ wing-assisted incline running (WAIR), rather than flying, to reach elevated refuges (such as cliffs, trees, and boulders). From the day of hatching and before attaining sustained aerial flight, developing ground birds use WAIR to enhance their locomotor performance through improved foot traction, ultimately permitting vertical running. WAIR provides insight from behaviors observable in living birds into the possible role of incipient …

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Soil Fungi And The Effects Of An Invasive Forb On Grasses: Neighbor Identity Matters, Ragan M. Callaway, Bruce E. Mahall, Chris Wicks, Joel Pankey, Catherine Zabinski Jan 2003

Soil Fungi And The Effects Of An Invasive Forb On Grasses: Neighbor Identity Matters, Ragan M. Callaway, Bruce E. Mahall, Chris Wicks, Joel Pankey, Catherine Zabinski

Biological Sciences Faculty Publications

We studied the effects of soil fungi on interactions between Centaurea melitensis, an exotic invasive weed in central California, and two co-occurring grasses, Nassella pulchra and Avena barbata. The fungicide benomyl reduced the abundance of arbuscular mycorrhizal (AM) fungi in plant roots but did not affect non-AM fungi. Centaurea plants grown alone were >50% smaller with the resident microbial community intact than when benomyl was applied. When grown with Nassella, the effect of benomyl was reversed. Centaurea grew almost five times larger with the resident microbial community intact. Fungicide had no effect on the biomass of Centaurea …

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Gyra Mutations In Ciprofloxacin-Resistant Bartonella Bacilliformis Strains Obtained In Vitro, Michael F. Minnick, Zachary R. Wilson, Laura S. Smitherman, D. Scott Samuels Jan 2003

Gyra Mutations In Ciprofloxacin-Resistant Bartonella Bacilliformis Strains Obtained In Vitro, Michael F. Minnick, Zachary R. Wilson, Laura S. Smitherman, D. Scott Samuels

Biological Sciences Faculty Publications

We isolated and characterized mutants of Bartonella bacilliformis that are resistant to the fluoroquinolone antibiotic ciprofloxacin, which targets the A subunit of DNA gyrase. Mutants had single point mutations in the gyrA gene that changed either Asp-90 to Gly or Asp-95 to Asn and had 3- or 16-fold higher resistance, respectively, to ciprofloxacin than did wild-type B. bacilliformis. Asp-95 is homologous to Asp-87 of Escherichia coli GyrA and is a common residue mutated in fluoroquinolone-resistant strains of other bacteria. This is the first report of a mutation at an Asp-90 homologue, which corresponds to Asp-82 in E. coli GyrA.

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An Arthropod Defensin Expressed By The Hemocytes Of The American Dog Tick, Dermacentor Variabilis (Acari: Ixodidae), Shane M. Ceraul, Daniel E. Sonenshine, Robert E. Ratzlaff, Wayne L. Hynes Jan 2003

An Arthropod Defensin Expressed By The Hemocytes Of The American Dog Tick, Dermacentor Variabilis (Acari: Ixodidae), Shane M. Ceraul, Daniel E. Sonenshine, Robert E. Ratzlaff, Wayne L. Hynes

Biological Sciences Faculty Publications

Both soluble and cell-mediated components are involved in the innate immune response of arthropods. Injection of Borrelia burgdorferi, the Lyme disease agent, results in the secretion of defensin into the hemolymph of the ixodid tick, Dermacentor variabilis. The presence of the peptide is observed as early as 15 min post-challenge and remains present through 18 h post-challenge. As observed in insects and soft ticks, the transcript for defensin is detected as early as 1 h post-challenge in D. variabilis. RT-PCR resulted in an amplicon of 624 bp with a 225 bp region that translates to a 74 …

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Increase In Biomass And Soldier Production For Coptotermes Formosanus (Shiraki) Workers Maintained In The Laboratory For Up To Nine Months, Deborah Waller Jan 2003

Increase In Biomass And Soldier Production For Coptotermes Formosanus (Shiraki) Workers Maintained In The Laboratory For Up To Nine Months, Deborah Waller

Biological Sciences Faculty Publications

The factors that influence rates of soldier production in subterranean termites are poorly understood. In the present study, foraging groups of Coptotermes formosanus Shiraki were collected from baldcypress trees in Lake Charles, Lousiana, in November 1985, and February, April/May and August 1986. Termites were maintained in the laboratory for nine months, seven months, four/five months and zero months, respectively, and then examined for survivorship, termite biomass and soldier production after incubation for an additional five weeks at 30° C. Within collection periods, there was no association between survivorship and soldier production or between mean dry biomass and soldier production. However, …

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Chemical Composition Of Some Components Of The Arrestment Pheromone Of The Black-Legged Tick, Ixodes Scapularis (Acari : Ixodidae) And Their Use In Tick Control, Daniel E. Sonenshine, Trevor Adams, Sandra A. Allan, John Mclaughlin, Francis X. Webster Jan 2003

Chemical Composition Of Some Components Of The Arrestment Pheromone Of The Black-Legged Tick, Ixodes Scapularis (Acari : Ixodidae) And Their Use In Tick Control, Daniel E. Sonenshine, Trevor Adams, Sandra A. Allan, John Mclaughlin, Francis X. Webster

Biological Sciences Faculty Publications

Chemical analysis (high-performance liquid chromatography) and bioassay demonstrated the presence of compounds that seem to be components of the Ixodes scapularis arrestment pheromone. Only two purines, guanine and xanthine, were found in acidified saline extracts made from cast skins after molting of fed nymphs, fed larvae, and fecal/excretory exudates deposited by unfed adults on substrates in their environment. The ratio of guanine to xanthine was 10.6:1 in an extract from the nymphal skins versus 0.95:1 in an extract from the larval skins. Guanine, xanthine, and traces of a third purine, tentatively identified as 8-azaguanine, were found in extracts made from …

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Multiple Transporters Associated With Malaria Parasite Responses To Chloroquine And Quinine, Jianbing Mu, Michael T. Ferdig, Xiaorong Feng, Deirdre A. Joy, Junhui Duan, Tetsuya Furuya, G. Subramanian, L. Aravind, Roland A. Cooper, John C. Wootton, Momia Xiong, Xin-Zhuan Su Jan 2003

Multiple Transporters Associated With Malaria Parasite Responses To Chloroquine And Quinine, Jianbing Mu, Michael T. Ferdig, Xiaorong Feng, Deirdre A. Joy, Junhui Duan, Tetsuya Furuya, G. Subramanian, L. Aravind, Roland A. Cooper, John C. Wootton, Momia Xiong, Xin-Zhuan Su

Biological Sciences Faculty Publications

Mutations and/or overexpression of various transporters are known to confer drug resistance in a variety of organisms. In the malaria parasite Plasmodium falciparum, a homologue of P-glycoprotein, PfMDR1, has been implicated in responses to chloroquine (CO), quinine (ON) and other drugs, and a putative transporter, PfCRT, was recently demonstrated to be the key molecule in CO resistance. However, other unknown molecules are probably involved, as different parasite clones carrying the same pfcrt and pfmdr1 alleles show a wide range of quantitative responses to CO and ON. Such molecules may contribute to increasing incidences of ON treatment failure, the molecular basis …

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Enhancement Of Disease And Pathology By Synergy Of Trichuris Suis And Campylobacter Jejuni In The Colon Of Immunologically Naive Swine, Linda S. Mansfield, David T. Gauthier, Sheila R. Abner, Kathryn M. Jones, Stacey R. Wilder, Joseph F. Urban Jan 2003

Enhancement Of Disease And Pathology By Synergy Of Trichuris Suis And Campylobacter Jejuni In The Colon Of Immunologically Naive Swine, Linda S. Mansfield, David T. Gauthier, Sheila R. Abner, Kathryn M. Jones, Stacey R. Wilder, Joseph F. Urban

Biological Sciences Faculty Publications

Campylobacter jejuni, a leading cause of bacterial gastroenteritis, has different age distribution and disease expression in developing and developed countries, which may be due to the endemnicity of infection and the age of acquisition of immunity. Differences in disease expression are not solely dependent on the C jejuni strain or virulence attributes. Another modulating factor in developing countries may be endemic nematode infections such as Trichuris, which drive type 2 cytokine responses and down-regulate type I immune responses. In this study, three-day-old germfree pigs given dual infections with Trichuris suis and C jejuni had more frequent, more severe …

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Experimental Mycobacteriosis In Striped Bass Morone Saxatilis, D. T. Gauthier, M. W. Rhodes, W. K. Vogelbein, H. Kator, C. A. Ottinger Jan 2003

Experimental Mycobacteriosis In Striped Bass Morone Saxatilis, D. T. Gauthier, M. W. Rhodes, W. K. Vogelbein, H. Kator, C. A. Ottinger

Biological Sciences Faculty Publications

Striped bass Morone saxatilis were infected intraperitoneally with approximately 105 Mycobacterium marinum, M. shottsii sp. nov., or M. gordonae. Infected fish were maintained in a flow-through freshwater system at 18 to 21°C, and were examined histologically and bacteriologically at 2, 4, 6, 8, 17, 26, 36 and 45 wk post-infection (p.i.). M. marinum caused acute peritonitis, followed by extensive granuloma development in the mesenteries, spleen and anterior kidney. Granulomas in these tissues underwent a temporal progression of distinct morphological stages, culminating in well-circumscribed lesions surrounded by normal or healing tissue. Mycobacteria were cultured in high numbers from …

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Recognizing Toxic Species In Aquatic Habitats: A Potential Concern In Lake Management, Mikolaj Kokocinski, Harold G. Marshall Jan 2003

Recognizing Toxic Species In Aquatic Habitats: A Potential Concern In Lake Management, Mikolaj Kokocinski, Harold G. Marshall

Biological Sciences Faculty Publications

The importance of distinguishing toxic and non-toxic algal species is becoming a more common problem for management decisions associated with various freshwater and estuarine habitats. An example is given where two dinoflagellates, originally unidentified as closely resembling the toxin producing Pfiesteria spp., have been compared to these species. In order to clarify any relationship to Pfiesteria spp., scanning electron microscopy was used to determine the plate tabulation patterns of these dinoflagellates and make comparisons to the tabulation present in Pfiesteria spp. The results indicated significant differences in the plate tabulations of these taxa to distinguish them from Pfiesteria …

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Hydrodynamic Stability Of Swimming In Ostraciid Fishes: Role Of The Carapace In The Smooth Trunkfish Lactophrys Triqueter (Teleostei : Ostraciidae), Ian K. Bartol, Morteza Gharib, Daniel Weihs, Paul W. Webb, Jay R. Hove, Malcolm S. Gordon Jan 2003

Hydrodynamic Stability Of Swimming In Ostraciid Fishes: Role Of The Carapace In The Smooth Trunkfish Lactophrys Triqueter (Teleostei : Ostraciidae), Ian K. Bartol, Morteza Gharib, Daniel Weihs, Paul W. Webb, Jay R. Hove, Malcolm S. Gordon

Biological Sciences Faculty Publications

The hydrodynamic bases for the stability of locomotory motions in fishes are poorly understood, even for those fishes, such as the rigid-bodied smooth trunkfish Lactophrys triqueter, that exhibit unusually small amplitude recoil movements during rectilinear swimming. We have studied the role played by the bony carapace of the smooth trunkfish in generating trimming forces that self-correct for instabilities. The flow patterns, forces and moments on and around anatomically exact, smooth trunkfish models positioned at both pitching and yawing angles of attack were investigated using three methods: digital particle image velocimetry (DPIV), pressure distribution measurements, and force balance measurements. Models …

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Algal Composition And Abundance In The Neuston Surface Micro Layer From A Lake And Pond In Virginia (U.S.A.), Lubomira Burchardt, Harold G. Marshall Jan 2003

Algal Composition And Abundance In The Neuston Surface Micro Layer From A Lake And Pond In Virginia (U.S.A.), Lubomira Burchardt, Harold G. Marshall

Biological Sciences Faculty Publications

A comparative study was conducted that characterized the algae within the neuston, ca 2 mm below the surface, and the algae in the water column from two freshwater habitats. There were significant differences in total algal abundance and the abundance of diatoms, cyanoprokaryotes, and chlorophytes between the neuston and water column algae of these two regions during each season and at both sites. The pond neuston was dominated by chlorophytes, with total algal abundance ranging seasonally from 0.6 to 59.6 x 10-3 cells ml-1 compared to water column algal concentrations of 4.1 to 40.4 x 10-3 cells ml-1. …

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