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Biological Sciences Faculty Publications

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Articles 1231 - 1260 of 1571

Full-Text Articles in Life Sciences

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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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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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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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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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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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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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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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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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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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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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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Characteristic Genome Rearrangements In Experimental Evolution Of Saccharomyces Cerevisiae, Maitreya J. Dunham, Hassan Badrane, Tracy Ferea, Julian Adams, Patrick O. Brown, Frank Rosenzweig, David Botstein Dec 2002

Characteristic Genome Rearrangements In Experimental Evolution Of Saccharomyces Cerevisiae, Maitreya J. Dunham, Hassan Badrane, Tracy Ferea, Julian Adams, Patrick O. Brown, Frank Rosenzweig, David Botstein

Biological Sciences Faculty Publications

Genome rearrangements, especially amplifications and deletions, have regularly been observed as responses to sustained application of the same strong selective pressure in microbial populations growing in continuous culture. We studied eight strains of budding yeast (Saccharomyces cerevisiae) isolated after 100-500 generations of growth in glucose-limited chemostats. Changes in DNA copy number were assessed at single-gene resolution by using DNA microarray-based comparative genomic hybridization. Six of these evolved strains were aneuploid as the result of gross chromosomal rearrangements. Most of the aneuploid regions were the result of translocations, including three instances of a shared breakpoint on chromosome 14 immediately adjacent to …

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Plasticity And Genetic Diversity May Allow Saltcedar To Invade Cold Climates In North America, Jason P. Sexton, J. K. Mckay, Anna Sala Dec 2002

Plasticity And Genetic Diversity May Allow Saltcedar To Invade Cold Climates In North America, Jason P. Sexton, J. K. Mckay, Anna Sala

Biological Sciences Faculty Publications

Two major mechanisms have been proposed to explain the ability of introduced populations to colonize over large habitat gradients, despite significant population bottlenecks during introduction: (1) Broad environmental tolerance-successful invaders possess life history traits that confer superior colonizing ability and/or phenotypic plasticity, allowing acclimation to a wide range of habitats. (2) Local adaptation-successful invaders rapidly adapt to local selective pressures. However, even with bottlenecks, many introduced species exhibit surprisingly high levels of genetic variation and thus the potential for evolutionary increases in invasive traits and plasticity. Here we assess the invasive potential of Tamarix ramosissima, by examining the degree of …

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Convergent Demographic Effects Of Insect Attack On Related Thistles In Coastal Vs. Continental Dunes, John L. Maron, Julie K. Combs, Svata M. Louda Dec 2002

Convergent Demographic Effects Of Insect Attack On Related Thistles In Coastal Vs. Continental Dunes, John L. Maron, Julie K. Combs, Svata M. Louda

Biological Sciences Faculty Publications

Insect herbivory is common, but the conditions under which it reduces the fitness and population size of plants remain poorly understood. We quantified population-level impacts of floral herbivory by specialized insects on cobweb thistle (Cirsium occidentale var. occidentale) in a California coastal dune ecosystem, and then compared these demographic effects to those published for Platte thistle (Cirsium canescens) in similarly designed exclusion experiments in the continental sand dune ecosystem in the Great Plains. As a separate test of the strength of the seed-to-seedling linkage, we quantified seedling establishment rates in seed addition plots and compared these …

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Groel Expression In Gyrb Mutants Of Borrelia Burgdorferi, Janet Alverson, D. Scott Samuels Nov 2002

Groel Expression In Gyrb Mutants Of Borrelia Burgdorferi, Janet Alverson, D. Scott Samuels

Biological Sciences Faculty Publications

GroEL protein and groEL mRNA transcript were up-regulated in gyrB mutants of Borrelia burgdorferi, a causative agent of Lyme disease. Furthermore, the protein and transcript levels in gyrB mutants were greater than those in experimentally heat-shocked cultures of wild-type B. burgdorferi. Circular DNA in the gyrB mutants was more relaxed than in wild-type cells, although groEL is on the linear chromosome of B. burgdorferi. To our knowledge, this is the first evidence, albeit indirect, for the effect of DNA topology on gene expression from a linear DNA molecule in a bacterium.

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Culture-Independent Microbial Community Analysis Reveals That Inulin In The Diet Primarily Affects Previously Unknown Bacteria In The Mouse Cecum, Juha H. A. Apajalahti, Hannele Kettunen, Anu Kettunen, William E. Holben, Päivi H. Nurminen, Nina Rautonen, Marja Mutanen Oct 2002

Culture-Independent Microbial Community Analysis Reveals That Inulin In The Diet Primarily Affects Previously Unknown Bacteria In The Mouse Cecum, Juha H. A. Apajalahti, Hannele Kettunen, Anu Kettunen, William E. Holben, Päivi H. Nurminen, Nina Rautonen, Marja Mutanen

Biological Sciences Faculty Publications

Inulin is a well-known fructose-based prebiotic which has been shown to stimulate the growth of bifidobacteria, a bacterial group generally considered beneficial for intestinal health. In the present study, we analyzed inulin-associated shifts in the total bacterial community of wild-type mice and mice carrying a genetically inactivated adenomatous polyposis coli tumor suppressor gene by using DNA-based approaches independent of bacterial culturability. Mice were fed a high-fat, nonfiber diet with or without inulin inclusion at a 10% (wt/wt) concentration. Cecal contents were analyzed after 0, 3, and 9 weeks on the experimental diets. Inulin inclusion significantly affected the total bacterial community …

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Molecular Mechanisms Of Metabolic Arrest: Life In Limbo (Book Review), Bernard Rees Oct 2002

Molecular Mechanisms Of Metabolic Arrest: Life In Limbo (Book Review), Bernard Rees

Biological Sciences Faculty Publications

No abstract provided.

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Distinct Interactions Of Gtp, Utp, And Ctp With G(S) Proteins, Andreas Gille, Hui-Yu Liu, Stephen R. Sprang, Roland Seifert Sep 2002

Distinct Interactions Of Gtp, Utp, And Ctp With G(S) Proteins, Andreas Gille, Hui-Yu Liu, Stephen R. Sprang, Roland Seifert

Biological Sciences Faculty Publications

Early studies showed that in addition to GTP, the pyrimidine nucleotides UTP and CTP support activation of the adenylyl cyclase (AC)-stimulating G(s) protein. The aim of this study was to elucidate the mechanism by which UTP and CTP support G(s) activation. As models, we used S49 wild-type lymphoma cells, representing a physiologically relevant system in which the beta(2)-adrenoreceptor (beta(2)AR) couples to G(s), and Sf9 insect cell membranes expressing beta(2)AR-Galpha(s) fusion proteins. Fusion proteins provide a higher sensitivity for the analysis of beta(2)AR-G(s) coupling than native systems. Nucleoside 5'-triphosphates (NTPs) supported agonist-stimulated AC activity in the two systems and basal AC …

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Review Of: Riverine Flood Plains: Present State And Future Trends, Klement Tockner, Jack Arthur Stanford Sep 2002

Review Of: Riverine Flood Plains: Present State And Future Trends, Klement Tockner, Jack Arthur Stanford

Biological Sciences Faculty Publications

Natural flood plains are among the most biologically productive and diverse ecosystems on earth. Globally, riverine flood plains cover > 2 x 10(6) km(2), however, they are among the most threatened ecosystems. Floodplain degradation is closely linked to the rapid decline in freshwater biodiversity; the main reasons for the latter being habitat alteration, flow and flood control, species invasion and pollution. In Europe and North America, up to 90% of flood plains are already 'cultivated' and therefore functionally extinct. In the developing world, the remaining natural flood plains are disappearing at an accelerating rate, primarily as a result of changing hydrology. …

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Current Issues In Forensic Dna Profiling, Dan E. Krane Sep 2002

Current Issues In Forensic Dna Profiling, Dan E. Krane

Biological Sciences Faculty Publications

No abstract provided.

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Cosolvent-Induced Transformation Of A Death Domain Tertiary Structure, Tsan Xiao, Kevin H. Gardner, Stephen R. Sprang Aug 2002

Cosolvent-Induced Transformation Of A Death Domain Tertiary Structure, Tsan Xiao, Kevin H. Gardner, Stephen R. Sprang

Biological Sciences Faculty Publications

The death domain (DD) of the protein kinase Pelle adopts a six-helix bundle fold in the crystal structure of the complex with its dimerization partner, Tube-DD. However, in crystals obtained from a solution of 45% 2-methyl-2,4-pentanediol (MPD), the C-terminal half of Pelle-DD folds into a single helix, and the N-terminal half of the molecule is disordered. The helical segment forms an antiparallel dimer with the corresponding helix of a symmetry-related molecule, and together they form extensive lattice interactions similar in number, composition, and buried surface to those in the six-helix bundle of the native fold. Secondary structure analysis by heteronuclear …

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The Neisseria Lipooligosaccharide-Specific Alpha-2,3-Sialyltransferase Is A Surface-Exposed Outer Membrane Protein, Dawn M. Shell, Lisa Chiles, Ralph C. Judd, Samar Seal, Richard F. Rest Jul 2002

The Neisseria Lipooligosaccharide-Specific Alpha-2,3-Sialyltransferase Is A Surface-Exposed Outer Membrane Protein, Dawn M. Shell, Lisa Chiles, Ralph C. Judd, Samar Seal, Richard F. Rest

Biological Sciences Faculty Publications

Neisseria gonorrhoeae and Neisseria meningitidis express an similar to43-kDa alpha-2,3-sialyltransferase (Lst) that sialylates the surface lipooligosaccharide (LOS) by using exogenous (in all N. gonorrhoeae strains and some N. meningitidis serogroups) or endogenous (in other N. meningitidis serogroups) sources of 5'-cytidinemonophospho-N-acetylneuraminic acid (CMP-NANA). Sialylation of LOS can protect N. gonorrhoeae and N. meningitidis from complement-mediated serum killing and from phagocytic killing by neutrophils. The precise subcellular location of Lst has not been determined. We confirm and extend previous studies by demonstrating that Lst is located in the outer membrane and is surface exposed in both N. gonorrhoeae and N. meningitidis. Western …

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Genetic Evidence That Interhelical Packing Interactions In The Gp41 Core Are Critical For Transition Of The Human Immunodeficiency Virus Type 1 Envelope Glycoprotein To The Fusion-Active State, Kathryn E. Follis, Scott J. Larson, Min Lu, Jack H. Nunberg Jul 2002

Genetic Evidence That Interhelical Packing Interactions In The Gp41 Core Are Critical For Transition Of The Human Immunodeficiency Virus Type 1 Envelope Glycoprotein To The Fusion-Active State, Kathryn E. Follis, Scott J. Larson, Min Lu, Jack H. Nunberg

Biological Sciences Faculty Publications

The envelope glycoprotein complex (gp120-gp41) of human immunodeficiency virus type 1 (HIV-1) promotes the fusion of viral and cellular membranes through formation of the fusion-active six-helix bundle in the gp41 ectodomain. This gp41 core structure consists of three C-terminal helices packed in an antiparallel manner into hydrophobic grooves on the surface of the N-terminal trimeric coiled coil. Alanine mutations that destabilize the N- and C-terminal interhelical packing interactions also reduce viral infectivity. Here we show that viruses bearing these mutations exhibit a marked potentiation of inhibition by peptides that make up the gp41 core. By contrast, these viruses are unchanged …

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Computational Simulation Of The Docking Of Prochlorothrix Hollandica Plastocyanin To Photosystem I: Modeling The Electron Transfer Complex, George S. Bullerjahn, Neocles B. Leontis, Eugene Myshkin Jun 2002

Computational Simulation Of The Docking Of Prochlorothrix Hollandica Plastocyanin To Photosystem I: Modeling The Electron Transfer Complex, George S. Bullerjahn, Neocles B. Leontis, Eugene Myshkin

Biological Sciences Faculty Publications

We have used several docking algorithms (GRAMM, FTDOCK, DOT, AUTODOCK) to examine protein-protein interactions between plastocyanin (Pc)/photosystem I (PSI) in the electron transfer reaction. Because of the large size and complexity of this system, it is faster and easier to use computer simulations than conduct x-ray crystallography or nuclear magnetic resonance experiments. The main criterion for complex selection was the distance between the copper ion of Pc and the P700 chlorophyll special pair. Additionally, the unique tyrosine residue (Tyr(12)) of the hydrophobic docking surface of Prochlorothrix hollandica Pc yields a specific interaction with the lumenal surface of PSI, thus providing …

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