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Structure Of The Gdp-Pi Complex Of Gly203→Ala G(Iα1): A Mimic Of The Ternary Product Complex Of Galpha-Catalyzed Gtp Hydrolysis, Albert M. Berghuis, Ethan Lee, André S. Raw, Alfred G. Gilman, Stephen R. Sprang
Structure Of The Gdp-Pi Complex Of Gly203→Ala G(Iα1): A Mimic Of The Ternary Product Complex Of Galpha-Catalyzed Gtp Hydrolysis, Albert M. Berghuis, Ethan Lee, André S. Raw, Alfred G. Gilman, Stephen R. Sprang
Biological Sciences Faculty Publications
Background: G proteins play a vital role in transmembrane signalling events. In their inactive form G proteins exist as heterotrimers consisting of an α subunit, complexed with GDP and a dimer of βγ subunits. Upon stimulation by receptors, G protein α subunits exchange GDP for GTP and dissociate from βγ. Thus activated, α subunits stimulate or inhibit downstream effectors. The duration of the activated state corresponds to the single turnover rate of GTP hydrolysis, which is typically in the range of seconds. In G(iα1), the Gly203→Ala mutation reduces the affinity of the substrate for Mg2+, inhibits a key …
Structures Of The Extracellular Domain Of The Type I Tumor Necrosis Factor Receptor, James H. Naismith, Tracey Q. Devine, Tadahiko Kohno, Stephen R. Sprang
Structures Of The Extracellular Domain Of The Type I Tumor Necrosis Factor Receptor, James H. Naismith, Tracey Q. Devine, Tadahiko Kohno, Stephen R. Sprang
Biological Sciences Faculty Publications
Background: Tumor necrosis factor (TNF) is a powerful cytokine that is involved in immune and pro-inflammatory responses. Two TNF receptors that belong to the cysteine-rich low affinity nerve growth factor receptor family (TNF-R1 and TNF-R2) are the sole mediators of TNF signalling. Signalling is thought to occur when a trimer of TNF binds to the extracellular domains of two or three receptor molecules, which permits aggregation and activation of the cytoplasmic domains. The complex is then internalized within an endocytic vesicle, whereupon it dissociates at low pH. Structure of the soluble extracellular domain of the receptor (sTNF-R1) both in the …
Directed Insertion Of A Selectable Marker Into A Circular Plasmid Of Borrelia Burgdorferi, Patricia Rosa, D. Scott Samuels, Daniel Hogan, Brian Stevenson, Sherwood Casjens, Kit Tilly
Directed Insertion Of A Selectable Marker Into A Circular Plasmid Of Borrelia Burgdorferi, Patricia Rosa, D. Scott Samuels, Daniel Hogan, Brian Stevenson, Sherwood Casjens, Kit Tilly
Biological Sciences Faculty Publications
Studies of the biology of Borrelia burgdorferi and the pathogenesis of Lyme disease are severely limited by the current lack of genetic tools. As an initial step toward facile genetic manipulation of this pathogenic spirochete, we have investigated gene inactivation by allelic exchange using a mutated borrelial gyrB gene that confers resistance to the antibiotic coumermycin A(1) as a selectable marker. We have transformed B. burgdorferi by electroporation with a linear fragment of DNA in which this selectable marker was flanked by sequences from a native borrelial 26-kb circular plasmid. We have identified coumermycin A(1)-resistant transformants in which gyrB had …
Competition And Facilitation: Contrasting Effects Of Artemisia Tridentata On Desert Vs Montane Pines, Ragan M. Callaway, Eh Delucia, Darrin Moore, R Nowak, W. H. Schlesinger, Brenda J. Moor
Competition And Facilitation: Contrasting Effects Of Artemisia Tridentata On Desert Vs Montane Pines, Ragan M. Callaway, Eh Delucia, Darrin Moore, R Nowak, W. H. Schlesinger, Brenda J. Moor
Biological Sciences Faculty Publications
Circumstantial evidence suggests that Artemisia tridentata may out-compete Pinus ponderosa and P. jefferyi for water at ecotones between shrub steppe and montane forest vegetation in the Great Basin. Other studies indicate that within the shrub steppe Artemisia may act as a nurse plant for a third species of pine, P. monophylla. We used field experiments to study these contrasting effects of Artemisia on P, ponderosa and P. monophylla within the contest of the distributional patterns in western Nevada of all three species on andesite, and on sites where hydrothermal activity has altered the andesite. At intermediate elevations in the Great …
Open-Path Fourier Transform Infrared Studies Of Large-Scale Laboratory Biomass Fires, Robert J. Yokelson, David W. T. Griffith, Darold E. Ward
Open-Path Fourier Transform Infrared Studies Of Large-Scale Laboratory Biomass Fires, Robert J. Yokelson, David W. T. Griffith, Darold E. Ward
Chemistry and Biochemistry Faculty Publications
A series of nine large-scale, open fires was conducted in the Intermountain Fire Sciences Laboratory (IFSL) controlled-environment combustion facility. The fuels were pure pine needles or sagebrush or mixed fuels simulating forest-floor, ground fires; crown fires; broadcast burns; and slash pile burns. Mid-infrared spectra of the smoke were recorded throughout each fire by open path Fourier transform infrared (FTIR) spectroscopy at 0.12 cm−1 resolution over a 3 m cross-stack pathlength and analyzed to provide pseudocontinuous, simultaneous concentrations of up to 16 compounds. Simultaneous measurements were made of fuel mass loss, stack gas temperature, and total mass flow up the …
Challenges In The Quest For Keystones, M. E. Power, D. Tilman, J. A. Estes, B. A. Menge, W. J. Bond, L. Scott Mills, G. Daily, J. C. Castilla, J. Lubchenco, R. T. Paine
Challenges In The Quest For Keystones, M. E. Power, D. Tilman, J. A. Estes, B. A. Menge, W. J. Bond, L. Scott Mills, G. Daily, J. C. Castilla, J. Lubchenco, R. T. Paine
Wildlife Biology Faculty Publications
Identifying keystone species is difficult-but essential to understanding bow loss of species will affect ecosystems.
A Protocol For Ecosystem Management, Jack A. Stanford, G. C. Poole
A Protocol For Ecosystem Management, Jack A. Stanford, G. C. Poole
Biological Sciences Faculty Publications
No abstract provided.
Abiotic Stress And The Relative Importance Of Interference And Facilitation In Montane Bunchgrass Communities In Western Montana, John T. Greenlee, Ragan M. Callaway
Abiotic Stress And The Relative Importance Of Interference And Facilitation In Montane Bunchgrass Communities In Western Montana, John T. Greenlee, Ragan M. Callaway
Biological Sciences Faculty Publications
No abstract provided.
Habitat Sampling And Habitat Selection By Female Wild Turkeys: Ecological Correlates And Reproductive Consequences, A. V. Badyaev, Thomas E. Martin, W. J. Etges
Habitat Sampling And Habitat Selection By Female Wild Turkeys: Ecological Correlates And Reproductive Consequences, A. V. Badyaev, Thomas E. Martin, W. J. Etges
Wildlife Biology Faculty Publications
Habitat sampling can allow much more effective habitat selection for longterm activities such as nesting and may be directly linked to fitness. We studied the process of habitat sampling and selection in female Wild Turkeys (Meleagris gallopavo) in the Arkansas Ozarks. In particular, we tested the prediction that movements prior to selecting nesting habitat correlate with the quality of selected habitat. Our results supported the prediction that greater habitat sampling (as reflected by greater area covered prior to nesting) allows acquisition of better nesting habitat; greater movements were correlated with choice of better nesting sites with more cover that allow …
Evidence For Acquisition In Nature Of A Chromosomal 2,4-Dichlorophenoxyacetic Acid/(Alpha)-Ketoglutarate Dioxygenase Gene By Different Burkholderia Spp., V. Grace Matheson, Larry J. Forney, Yuichi Suwa, Cindy H. Nakahatsu, Alan J. Sexstone, William E. Holben
Evidence For Acquisition In Nature Of A Chromosomal 2,4-Dichlorophenoxyacetic Acid/(Alpha)-Ketoglutarate Dioxygenase Gene By Different Burkholderia Spp., V. Grace Matheson, Larry J. Forney, Yuichi Suwa, Cindy H. Nakahatsu, Alan J. Sexstone, William E. Holben
Biological Sciences Faculty Publications
We characterized the gene required to initiate the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) by the soil bacterium Burkholderia sp. strain TFD6, which hybridized to the tfdA gene of the canonical 2,4-D catabolic plasmid pJP4 under low-stringency conditions. Cleavage of the ether bond of 2,4-D by cell extracts of TFD6 proceeded by an (alpha)-ketoglutarate-dependent reaction,characteristic of TfdA (F. Fukumori and R. P. Hausinger, J. Bacteriol. 175:2083-2086, 1993). The TFD6 tfdA gene was identified in a recombinant plasmid which complemented a tfdA transposon mutant of TFD6 created by chromosomal insertion of Tn5. The plasmid also expressed TfdA activity in Escherichia coli …
Characterization Of A Chromosomally Encoded 2,4-Dichlorophenoxyacetic Acid/A-Ketoglutarate Dioxygenase From Burkholderia Sp. Strain Rasc, Yuichi Suwa, Alice D. Wright, Fumitasu Fukimori, Kathy A. Nummy, Robert P. Hausinger, William E. Holben, Larry J. Forney
Characterization Of A Chromosomally Encoded 2,4-Dichlorophenoxyacetic Acid/A-Ketoglutarate Dioxygenase From Burkholderia Sp. Strain Rasc, Yuichi Suwa, Alice D. Wright, Fumitasu Fukimori, Kathy A. Nummy, Robert P. Hausinger, William E. Holben, Larry J. Forney
Biological Sciences Faculty Publications
The findings of previous studies indicate that the genes required for metabolism of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) are typically encoded on broad-host-range plasmids. However, characterization of plasmid-cured strains of Burkholderia sp. strain RASC, as well as mutants obtained by transposon mutagenesis, suggested that the 2,4-D catabolic genes were located on the chromosome of this strain. Mutants of Burkholderia strain RASC unable to degrade 2,4-D (2,4-D- strains) were obtained by insertional inactivation with Tn5. One such mutant (d1) was shown to have Tn5 inserted in tfdARASC, which encodes 2,4-D/alpha-ketoglutarate dioxygenase. This is the first reported example of a …
Impact Of A Parasitic Plant On The Structure And Dynamics Of Salt Marsh Vegetation, Steven C. Pennings, Ragan M. Callaway
Impact Of A Parasitic Plant On The Structure And Dynamics Of Salt Marsh Vegetation, Steven C. Pennings, Ragan M. Callaway
Biological Sciences Faculty Publications
We investigated the effect of a native parasitic plant, Cuscuta salina, on the structure and dynamics of the plant community in a California salt marsh. Cuscuta was common in the middle marsh zones. The abundance of Cuscuta was positively correlated with the abundance of Limonium californicum at two sampling scales (0.25— and ≈\approx40—m2 quadrats). Sampling at the scale of individual plants indicated that the dominant plant in the marsh, Salicornia virginica, was preferred by Cuscuta as a host over Arthrocnemum subterminale, Limonium californicum, and Frankenia salina. This result was confirmed with host—choice experiments in the field. Based on spatial …
Temperature-Driven Variation In Substrate Oxygenation And The Balance Of Competition And Facilitation, Ragan M. Callaway, Leah King
Temperature-Driven Variation In Substrate Oxygenation And The Balance Of Competition And Facilitation, Ragan M. Callaway, Leah King
Biological Sciences Faculty Publications
Emergent wetland plants often alleviate the effects of anaerobic soils on root respiration by passively transporting oxygen belowground through continuous air spaces (aerenchyma) in leaves and roots. Oxygen leaked from the roots into the rhizosphere may oxidize minerals in the soil or become available to other plants. Some spatial patterns in marsh plant communities suggest interspecific facilitative interactions, but there is little experimental evidence for interplant facilitation via soil oxygenation. We investigated the capability of the widespread, highly aerenchymous wetland plant, Typa latifolia, to aerate sediments and affect the growth of two non—aerenchymous neighbors, Salix exigua and Myosotis laxa, both …
Analysis Of Linear Plasmid Dimers In Borrelia Burgdorferi Sensu Lato Isolates: Implications Concerning The Potential Mechanism Of Linear Plasmid Replication, Richard T. Marconi, Sherwood Casjens, Ulrike G. Munderloh, D. Scott Samuels
Analysis Of Linear Plasmid Dimers In Borrelia Burgdorferi Sensu Lato Isolates: Implications Concerning The Potential Mechanism Of Linear Plasmid Replication, Richard T. Marconi, Sherwood Casjens, Ulrike G. Munderloh, D. Scott Samuels
Biological Sciences Faculty Publications
The Borrelia genome is composed of a linear chromosome and a number of variable circular and linear plasmids. Atypically large linear plasmids of 92 to 105 kb have been identified in several Borrelia burgdorferi sensu lato isolates and characterized. These plasmids carry the p27 and ospAB genes, which in other isolates reside on a 50-kb plasmid. Here we demonstrate that these plasmids are dimers of the 50-kb ospAB plasmid (pAB50). The 94-kb plasmid from isolate VS116, pVS94, was an exception and did not hybridize with any plasmid gene probes. When this plasmid was used as a probe, homologous sequences in …
Age-Biased Spring Dispersal In Male Wild Turkeys, A. V. Badyaev, W. J. Etges, Thomas E. Martin
Age-Biased Spring Dispersal In Male Wild Turkeys, A. V. Badyaev, W. J. Etges, Thomas E. Martin
Wildlife Biology Faculty Publications
No abstract provided.
Pinus Ponderosa Seedling Establishment And The Influence Of Competition With The Bunchgrass Agropyron Spicatum, Peter F. Kolb, Ronald Robberecht
Pinus Ponderosa Seedling Establishment And The Influence Of Competition With The Bunchgrass Agropyron Spicatum, Peter F. Kolb, Ronald Robberecht
Forest Management Faculty Publications
Interspecific competition between Agropyron spicatum (Pursh.) Scrib. & Smith bunchgrasses and naturally established seedlings of Pinus ponderosa was examined within a pine/bunchgrass community. A wire mesh was used to separate bunchgrass culms from pine seedling shoots to determine if the bunchgrass canopy influenced the survival of pine seedlings. In addition, two lengths of root exclusion tubes were used to determine the effects of bunchgrass root overlap on pine seedlings. The bunchgrass canopy did not significantly affect pine seedling survival. However, root competition, presumably for water, significantly decreased pine seedling survival. Exclusion of bunchgrass roots from a 0.15-m- and 0.30-m-deep root …
Leptographium Pyrinum Is A Mycangial Fungus Of Dendroctonus Adjunctus, Diana Six, T. D. Paine
Leptographium Pyrinum Is A Mycangial Fungus Of Dendroctonus Adjunctus, Diana Six, T. D. Paine
Ecosystem and Conservation Sciences Faculty Publications
Several species of Dendroctonus (Coleop- tera: Scolytidae) have cuticular invaginations, or my- cangia, in the integument which are specialized for carrying specific symbiotic fungi. The mycangium of Dendroctonus adjunctus, located under a callus that surrounds the prothorax, has been recognized but the mycangial fungus has not yet been identified. Fungi from mycangia of Dendroctonus adjunctus were isolated and compared with Leptographium pyrinum and Ophiostoma adjuncti, two species of fungi known to be present in trees colonized by Dendroctonus ad- junctus. Fungi isolated from Dendroctonus adjunctus mycangia were determined to be morphologically and genetically identical to Leptographium pyrinum
Variation In Leaf Structure And Function In Quercus Douglasii Trees Differing In Root Architecture And Drought History, Ragan M. Callaway, Bruce E. Mahall
Variation In Leaf Structure And Function In Quercus Douglasii Trees Differing In Root Architecture And Drought History, Ragan M. Callaway, Bruce E. Mahall
Biological Sciences Faculty Publications
Seasonal changes in leaf specific mass, nitrogen, chlorophyll, and photosynthetic properties were measured for two groups of spatially intermixed Quercus douglasii trees with different drought histories and apparently different root architectures. One group, referred to as ''high-psi(pd) trees, included trees with low amounts of fine root biomass in the upper 50 cm of soil and high predawn xylem pressure potentials (psi(pd)) during summer drought. These two characteristics indicate that trees in this group have deep roots, which may reach the water table. The second group, referred to as ''low-psi(pd) trees, had three to five times higher fine root biomass in …
Seeing Double: Crystal Structures Of The Type I Tnf Receptor, James H. Naismith, Barbara J. Brandhuber, Tracey Q. Devine, Stephen R. Sprang
Seeing Double: Crystal Structures Of The Type I Tnf Receptor, James H. Naismith, Barbara J. Brandhuber, Tracey Q. Devine, Stephen R. Sprang
Biological Sciences Faculty Publications
The crystal structure of the extracellular domain of the type I tumor necrosis factor receptor (sTNF-R1) has been determined to 2.25 Å at pH 7.5. We have also solved the structure of sTNF-R1 at pH 3.7. sTNF-R1 is an elongated molecule consisting of a linear combination of four cysteine-rich motifs. Interestingly, the crystal structure reveals two distinct dimers of the receptor. One dimer is formed by a parallel arrangement of receptors, the other by an antiparallel arrangement of receptors. In the parallel arrangement of the receptors, the tumor necrosis factor (TNF) binding face of the receptor is completely exposed to …
Scaling Of Muscle Composition, Wing Morphology, And Intermittent Flight Behavior In Woodpeckers, Bret W. Tobalske
Scaling Of Muscle Composition, Wing Morphology, And Intermittent Flight Behavior In Woodpeckers, Bret W. Tobalske
Biological Sciences Faculty Publications
Existing theory and empirical evidence suggest that body size should have a profound influence upon the composition of flight muscles and the performance of intermittent flight in birds. I examine the relationships between functional morphology and intermittent flight behavior within a closely-related group of birds using six species of woodpeckers (Picidae): Downy Woodpecker (Picoides pubescens, 27.2 g), Red-naped Sapsucker (Sphyrapicus nuchalis, 47.4 g), Hairy Woodpecker (P. villosus, 70.5 g), Lewis' Woodpecker (Melanerpes lewis, 106.6 g), Northern Flicker (Colaptes auratus, 148.1 g), and Pileated Woodpecker (Dryocopus pileatus, 262.5 g). In woodpeckers with a body mass less than 100 g, the pectoralis …
Effects Of Regional Origin And Genotype On Intraspecific Root Communication In The Desert Shrub Ambrosia Dumosa (Asteraceae), Bruce E. Mahall, Ragan M. Callaway
Effects Of Regional Origin And Genotype On Intraspecific Root Communication In The Desert Shrub Ambrosia Dumosa (Asteraceae), Bruce E. Mahall, Ragan M. Callaway
Biological Sciences Faculty Publications
Previous work has shown that the contact inhibition that occurs among roots of Ambrosia dumosa shrubs has a self/nonself recognition capability. In the current study, we investigated some of the geographic and genotypic dimensions of this recognition capability by using root observation chambers to observe the effects of encounters of individual roots on root elongation rates. We measured such effects in encounters between roots of plants from the same region and compared these to effects in encounters between roots of plants from two different regions. We also measured effects of encounters between roots of plants from the same clones and …