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Articles 61 - 90 of 602

Full-Text Articles in Biology

Integrated Stress And Community Perceptions: Toward An Understanding Of Human-Cougar Tolerance, Lara Brenner Jan 2017

Integrated Stress And Community Perceptions: Toward An Understanding Of Human-Cougar Tolerance, Lara Brenner

Graduate Student Theses, Dissertations, & Professional Papers

Evidence suggests that cougars (Puma concolor) are beginning to recolonize their traditional range in the Midwestern and Eastern US, returning to a landscape and a social environment that have changed drastically in a century of absence. Any hope of the cougar’s persistence depends on both human tolerance of their presence and on cougar tolerance of disrupted habitat. In this thesis, we took advantage of diverse cougar policy in place in the Western US to explore variation in human attitudes and acceptability of cougars and in the cougar stress response. We validated a process to identify and extract cortisol …


Stability Of Cross-Feeding Polymorphisms In Microbial Communities, Ivana Gudelj, Margie Kinnersley, Peter Rashkov, Karen Schmidt, Frank Rosenzweig Dec 2016

Stability Of Cross-Feeding Polymorphisms In Microbial Communities, Ivana Gudelj, Margie Kinnersley, Peter Rashkov, Karen Schmidt, Frank Rosenzweig

Biological Sciences Faculty Publications

Cross-feeding, a relationship wherein one organism consumes metabolites excreted by another, is a ubiquitous feature of natural and clinically-relevant microbial communities and could be a key factor promoting diversity in extreme and/or nutrient-poor environments. However, it remains unclear how readily cross-feeding interactions form, and therefore our ability to predict their emergence is limited. In this paper we developed a mathematical model parameterized using data from the biochemistry and ecology of an E. coli cross-feeding laboratory system. The model accurately captures short-term dynamics of the two competitors that have been observed empirically and we use it to systematically explore the stability …


Cytochrome C Can Form A Well-Defined Binding Pocket For Hydrocarbons, Levi J. Mcclelland, Harmen B. Steele, Frank G. Whitby, Tung-Chung Mou, David Holley, J B. Ross, Stephen R. Sprang, Bruce E. Bowler Dec 2016

Cytochrome C Can Form A Well-Defined Binding Pocket For Hydrocarbons, Levi J. Mcclelland, Harmen B. Steele, Frank G. Whitby, Tung-Chung Mou, David Holley, J B. Ross, Stephen R. Sprang, Bruce E. Bowler

Biological Sciences Faculty Publications

Cytochrome c can acquire peroxidase activity when it binds to cardiolipin in mitochondrial membranes. The resulting oxygenation of cardiolipin by cytochrome c provides an early signal for the onset of apoptosis. The structure of this enzyme-substrate complex is a matter of considerable debate. We present three structures at 1.7-2.0 Å resolution of a domain-swapped dimer of yeast iso-1-cytochrome c with the detergents, CYMAL-5, CYMAL-6, and ω-undecylenyl-β-d-maltopyranoside, bound in a channel that places the hydrocarbon moieties of these detergents next to the heme. The heme is poised for peroxidase activity with water bound in place of Met80, which serves as the …


Ric-8a, A G Protein Chaperone With Nucleotide Exchange Activity Induces Long-Range Secondary Structure Changes In Gα, Ravi Kant, Baisen Zeng, Celestine J. Thomas, Brian Bothner, Stephen R. Sprang Dec 2016

Ric-8a, A G Protein Chaperone With Nucleotide Exchange Activity Induces Long-Range Secondary Structure Changes In Gα, Ravi Kant, Baisen Zeng, Celestine J. Thomas, Brian Bothner, Stephen R. Sprang

Biological Sciences Faculty Publications

Cytosolic Ric-8A has guanine nucleotide exchange factor (GEF) activity and is a chaperone for several classes of heterotrimeric G protein α subunits in vertebrates. Using Hydrogen-Deuterium Exchange-Mass Spectrometry (HDX-MS) we show that Ric-8A disrupts the secondary structure of the Gα Ras-like domain that girds the guanine nucleotide-binding site, and destabilizes the interface between the Gαi1 Ras and helical domains, allowing domain separation and nucleotide release. These changes are largely reversed upon binding GTP and dissociation of Ric-8A. HDX-MS identifies a potential Gα interaction site in Ric-8A. Alanine scanning reveals residues crucial for GEF activity within that sequence. HDX confirms that, …


Structural Basis For Negative Allosteric Modulation Of Glun2a-Containing Nmda Receptors, Feng Yi, Tung-Chung Mou, Katherine N. Dorsett, Robert A. Volkmann, Frank S. Menniti, Stephen R. Sprang, Kasper B. Hansen Sep 2016

Structural Basis For Negative Allosteric Modulation Of Glun2a-Containing Nmda Receptors, Feng Yi, Tung-Chung Mou, Katherine N. Dorsett, Robert A. Volkmann, Frank S. Menniti, Stephen R. Sprang, Kasper B. Hansen

Biological Sciences Faculty Publications

NMDA receptors mediate excitatory synaptic transmission and regulate synaptic plasticity in the central nervous system, but their dysregulation is also implicated in numerous brain disorders. Here, we describe GluN2A-selective negative allosteric modulators (NAMs) that inhibit NMDA receptors by stabilizing the apo state of the GluN1 ligand-binding domain (LBD), which is incapable of triggering channel gating. We describe structural determinants of NAM binding in crystal structures of the GluN1/2A LBD heterodimer, and analyses of NAM-bound LBD structures corresponding to active and inhibited receptor states reveal a molecular switch in the modulatory binding site that mediate the allosteric inhibition. NAM binding causes …


Kain V. Department Of Environmental Protection, Sarah M. Danno Aug 2016

Kain V. Department Of Environmental Protection, Sarah M. Danno

Public Land & Resources Law Review

Global climate change and its chronic frustrations generated passage of the Massachusetts Global Warming Solutions Act. The Massachusetts Legislature imposed time-bound implementation mandates on the Massachusetts Department of Environmental Protection with Massachusetts residents acting as compliance watchdogs. In Kain, the Supreme Judicial Court of Massachusetts interpreted the Act in favor of environmental integrity and strict agency compliance standards.


Nanosecond Dynamics Of Gαi1 Bound To Nucleotides Or Ric-8a, A Gα Chaperone With Gef Activity, Labe A. Black, Celestine J. Thomas, Gwendolyn N. Nix, Michelle C. Terwilliger, Stephen R. Sprang, J B. Ross Aug 2016

Nanosecond Dynamics Of Gαi1 Bound To Nucleotides Or Ric-8a, A Gα Chaperone With Gef Activity, Labe A. Black, Celestine J. Thomas, Gwendolyn N. Nix, Michelle C. Terwilliger, Stephen R. Sprang, J B. Ross

Biological Sciences Faculty Publications

Resistance to Inhibitors of Cholinesterase A (Ric-8A) is a 60-kDa cytosolic protein that has chaperone and guanine nucleotide exchange (GEF) activity toward heterotrimeric G protein α subunits of the i, q, and 12/13 classes, catalyzing the release of GDP from Gα and subsequent binding of GTP. In the absence of GTP or GTP analogs, and subsequent to GDP release, Gα forms a stable nucleotide-free complex with Ric-8A. In this study, time-resolved fluorescence anisotropy measurements were employed to detect local motions of Gαi1 labeled at selected sites with Alexa 488 (C5) fluorescent dye (Ax) in the GDP, GTPγS (collectively, GXP), and …


Activation Of G Proteins By Gtp And The Mechanism Of Gα-Catalyzed Gtp Hydrolysis, Stephen R. Sprang Aug 2016

Activation Of G Proteins By Gtp And The Mechanism Of Gα-Catalyzed Gtp Hydrolysis, Stephen R. Sprang

Biological Sciences Faculty Publications

This review addresses the regulatory consequences of the binding of GTP to the alpha subunits (Gα) of heterotrimeric G proteins, the reaction mechanism of GTP hydrolysis catalyzed by Gα and the means by which GTPase activating proteins (GAPs) stimulate the GTPase activity of Gα. The high energy of GTP binding is used to restrain and stabilize the conformation of the Gα switch segments, particularly switch II, to afford stable complementary to the surfaces of Gα effectors, while excluding interaction with Gβγ, the regulatory binding partner of GDP-bound Gα. Upon GTP hydrolysis, the energy of these conformational restraints is dissipated and …


Should Scientists Be Required To Use A Model-Based Solution To Adjust For Possible Distance-Based Detectability Bias?, Richard L. Hutto Jul 2016

Should Scientists Be Required To Use A Model-Based Solution To Adjust For Possible Distance-Based Detectability Bias?, Richard L. Hutto

Biological Sciences Faculty Publications

The most popular method used to gain an understanding of population trends or of differences in bird abundance among land condition categories is to use information derived from point counts. Unfortunately, various factors can affect one’s ability to detect birds, and those factors need to be controlled or accounted for so that any difference in one’s index among time periods or locations is an accurate reflection of differences in bird abundance and not differences in detectability. Avian ecologists could use appropriately sized fixed-area surveys to minimize the chance that they might be deceived by distance-based detectability bias, but the current …


Mutation-Driven Divergence And Convergence Indicate Adaptive Evolution Of The Intracellular Human-Restricted Pathogen, Bartonella Bacilliformis, Sandip Paul, Michael F. Minnick, Sujay Chattopadhyay May 2016

Mutation-Driven Divergence And Convergence Indicate Adaptive Evolution Of The Intracellular Human-Restricted Pathogen, Bartonella Bacilliformis, Sandip Paul, Michael F. Minnick, Sujay Chattopadhyay

Biological Sciences Faculty Publications

Among all species of Bartonella, human-restricted Bartonella bacilliformis is the most virulent but harbors one of the most reduced genomes. Carrión's disease, the infection caused by B. bacilliformis, has been afflicting poor rural populations for centuries in the high-altitude valleys of the South American Andes, where the pathogen's distribution is probably restricted by its sand fly vector's range. Importantly, Carrión's disease satisfies the criteria set by the World Health Organization for a disease amenable to elimination. However, to date, there are no genome-level studies to identify potential footprints of B. bacilliformis (patho)adaptation. Our comparative genomic approach demonstrates that the evolution …


Linking Native And Invader Traits Explains Native Spider Population Responses To Plant Invasion, Jennifer N. Smith, Douglas J. Emlen, Dean Pearson Apr 2016

Linking Native And Invader Traits Explains Native Spider Population Responses To Plant Invasion, Jennifer N. Smith, Douglas J. Emlen, Dean Pearson

Biological Sciences Faculty Publications

Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders’ web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely …


Insights From Wildfire Science: A Resource For Fire Policy Discussions, Tania Schoennagel, Penny Morgan, Jennifer Balch, Philip Dennison, Brian Harvey, Richard L. Hutto, Meg Krawchuk, Max A. Moritz, Ray Rasker, Cathy Whitlock Jan 2016

Insights From Wildfire Science: A Resource For Fire Policy Discussions, Tania Schoennagel, Penny Morgan, Jennifer Balch, Philip Dennison, Brian Harvey, Richard L. Hutto, Meg Krawchuk, Max A. Moritz, Ray Rasker, Cathy Whitlock

Biological Sciences Faculty Publications

Record blazes swept across parts of the US in 2015, burning more than 10 million acres. The four biggest fire seasons since 1960 have all occurred in the last 10 years, leading to fears of a ‘new normal’ for wildfire. Fire fighters and forest managers are overwhelmed, and it is clear that the policy and management approaches of the past will not suffice under this new era of western wildfires. In recent decades, state and federal policymakers, tribes, and others are confronting longer fire seasons (Jolly et al. 2015), more large fires (Dennison et al. 2014), a tripling of homes …


The Intervening Sequence Of Coxiella Burnetii: Characterization And Evolution, Indu Warrier, Mathias C. Walter, Dimitrios Frangoulidis, Rahul Raghavan, Linda D. Hicks, Michael F. Minnick Jan 2016

The Intervening Sequence Of Coxiella Burnetii: Characterization And Evolution, Indu Warrier, Mathias C. Walter, Dimitrios Frangoulidis, Rahul Raghavan, Linda D. Hicks, Michael F. Minnick

Biological Sciences Faculty Publications

The intervening sequence (IVS) of Coxiella burnetii, the agent of Q fever, is a 428-nt selfish genetic element located in helix 45 of the precursor 23S rRNA. The IVS element, in turn, contains an ORF that encodes a hypothetical ribosomal S23 protein (S23p). Although S23p can be synthesized in vitro in the presence of an engineered E. coli promoter and ribosome binding site, results suggest that the protein is not synthesized in vivo. In spite of a high degree of IVS conservation among different strains of C. burnetii, the region immediately upstream of the S23p start codon is prone to …


To Jump Or Not To Jump: Mule Deer (Odocoileus Hemionus) And White-Tailed Deer (Odocoileus Virginianus) Crossing Decisions, Emily N. Burkholder Jan 2016

To Jump Or Not To Jump: Mule Deer (Odocoileus Hemionus) And White-Tailed Deer (Odocoileus Virginianus) Crossing Decisions, Emily N. Burkholder

Undergraduate Theses, Professional Papers, and Capstone Artifacts

There have been recent efforts to enhance ungulate movement through modified fencing structures. Ungulates such as mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) typically negotiate fences by either jumping over fencing or going under. Here we examine crossing success and crossing decisions of mule deer and white-tailed deer and determine factors that influence crossing success and the impending decision to jump over or crawl underneath fencing. Using a BACI (Before-After-Control-Impact) design, we deployed remote cameras along fence lines in three study areas; Canadian Forces Base (CFB) Suffield and OneFour research center in Southeastern Alberta, …


Seasonal Dimorphism In Gastropod Hatchling Size: What Can We Learn From Egg Mass Morphology And Deposition Site Conditions?, Lily A. Harrison Jan 2016

Seasonal Dimorphism In Gastropod Hatchling Size: What Can We Learn From Egg Mass Morphology And Deposition Site Conditions?, Lily A. Harrison

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Egg size is one of the most important features of marine invertebrate reproduction because it provides insight into developmental patterns, offspring size, and adult investment per offspring. Intraspecific variation in egg size and the resulting hatchling size may depend on many factors including environmental and maternal conditions and geographic location. Therefore, both the season in which eggs are laid and the spatial heterogeneity of deposition sites may influence egg size and hatchling size. Natica chemnitzii deposits egg masses on sandy beaches along the coast of the Bay of Panama. During the wet (non-upwelling) season hatchling size is unimodal. However, monthly …


Impacts Of Recreational Aviation On Wildlife: The Physiological Stress Response In White-Tailed Deer (Odocoileus Virginianus) And Associated User Perceptions, Devin W. Landry Jan 2016

Impacts Of Recreational Aviation On Wildlife: The Physiological Stress Response In White-Tailed Deer (Odocoileus Virginianus) And Associated User Perceptions, Devin W. Landry

Graduate Student Theses, Dissertations, & Professional Papers

Recreational aviation on public lands may negatively impact wildlife. However, land-use decisions need to balance user need with wildlife impact. We know very little about 1) how back country airstrip use affects local wildlife, or 2) attitudes and perceptions of recreational pilots toward possible management actions. For my Master’s research, I investigated how aircraft activity influenced physiological measures of stress in white-tailed deer, while also modeling how psychometrics such as wildlife attitudes and place attachment predict the willingness of recreational pilots engage in impact-mitigating behaviors. I measured physiological stress through non-invasive sampling of stress hormones in fecal samples (fecal glucocorticoid …


Catalytic Mechanism Of Mammalian Adenylyl Cyclase: A Computational Investigation, David K. Hahn, Jose R. Tusell, Stephen R. Sprang, Xi Chu Oct 2015

Catalytic Mechanism Of Mammalian Adenylyl Cyclase: A Computational Investigation, David K. Hahn, Jose R. Tusell, Stephen R. Sprang, Xi Chu

Biological Sciences Faculty Publications

Adenylyl cyclase (AC) catalyzes the synthesis of cyclic AMP, an important intracellular regulatory molecule, from ATP. We propose a catalytic mechanism for class III mammalian AC based on density functional theory calculations. We employ a model of the AC active site derived from a crystal structure of mammalian AC activated by Gα·GTP and forskolin at separate allosteric sites. We compared the calculated activation free energies for 13 possible reaction sequences involving proton transfer, nucleophilic attack, and elimination of pyrophosphate. The proposed most probable mechanism is initiated by deprotonation of 3'OH and water-mediated transfer of the 3'H to the γ-phosphate. Proton …


Colonization Of Lutzomyia Verrucarum And Lutzomyia Longipalpis Sand Flies (Diptera: Psychodidae) By Bartonella Bacilliformis, The Etiologic Agent Of Carrion's Disease, James M. Battisti, Phillip G. Lawyer, Michael F. Minnick Oct 2015

Colonization Of Lutzomyia Verrucarum And Lutzomyia Longipalpis Sand Flies (Diptera: Psychodidae) By Bartonella Bacilliformis, The Etiologic Agent Of Carrion's Disease, James M. Battisti, Phillip G. Lawyer, Michael F. Minnick

Biological Sciences Faculty Publications

Bartonella bacilliformis is a pathogenic bacterium transmitted to humans presumably by bites of phlebotomine sand flies, infection with which results in a bi-phasic syndrome termed Carrion's disease. After constructing a low-passage GFP-labeled strain of B. bacilliformis, we artificially infected Lutzomyia verrucarum and L. longipalpis populations, and subsequently monitored colonization of sand flies by fluorescence microscopy. Initially, colonization of the two fly species was indistinguishable, with bacteria exhibiting a high degree of motility, yet still confined to the abdominal midgut. After 48h, B. bacilliformis transitioned from bacillus-shape to a non-motile, small coccoid form and appeared to be digested along with …


Toward A More Ecologically Informed View Of Severe Forest Fires, Richard L. Hutto, Robert E. Keane, Rosemary L. Sherriff, Christopher T. Rota, Lisa A. Eby, Victoria A. Saab Sep 2015

Toward A More Ecologically Informed View Of Severe Forest Fires, Richard L. Hutto, Robert E. Keane, Rosemary L. Sherriff, Christopher T. Rota, Lisa A. Eby, Victoria A. Saab

Biological Sciences Faculty Publications

We use the historical presence of high-severity fire patches in mixed-conifer forests of the western United States to make several points that we hope will encourage development of a more ecologically informed view of severe wildland fire effects. First, many plant and animal species use, and have sometimes evolved to depend on, severely burned forest conditions for their persistence. Second, evidence from fire history studies also suggests that a complex mosaic of severely burned conifer patches was common historically in the West. Third, to maintain ecological integrity in forests born of mixed-severity fire, land managers will have to accept some …


Linkage Mapping Reveals Strong Chiasma Interference In Sockeye Salmon: Implications For Interpreting Genomic Data, Morten T. Limborg, Ryan T. Waples, Fred W. Allendorf, James E. Seeb Sep 2015

Linkage Mapping Reveals Strong Chiasma Interference In Sockeye Salmon: Implications For Interpreting Genomic Data, Morten T. Limborg, Ryan T. Waples, Fred W. Allendorf, James E. Seeb

Biological Sciences Faculty Publications

Meiotic recombination is fundamental for generating new genetic variation and for securing proper disjunction. Further, recombination plays an essential role during the rediploidization process of polyploid-origin genomes because crossovers between pairs of homeologous chromosomes retain duplicated regions. A better understanding of how recombination affects genome evolution is crucial for interpreting genomic data; unfortunately, current knowledge mainly originates from a few model species. Salmonid fishes provide a valuable system for studying the effects of recombination in nonmodel species. Salmonid females generally produce thousands of embryos, providing large families for conducting inheritance studies. Further, salmonid genomes are currently rediploidizing after a whole …


Proteins Of Bartonella Bacilliformis:Candidates For Vaccine Development, Cesar Henriquez-Camocho, Palmira Ventosilla, Michael F. Minnick, Joaquim Ruiz, Ciro Maguina Aug 2015

Proteins Of Bartonella Bacilliformis:Candidates For Vaccine Development, Cesar Henriquez-Camocho, Palmira Ventosilla, Michael F. Minnick, Joaquim Ruiz, Ciro Maguina

Biological Sciences Faculty Publications

Bartonella bacilliformis is the etiologic agent of Carrion's disease suggest complex adaptations by the bacterium to the human host, with the overall objectives of persistence, maintenance of a reservoir state for vectorial transmission, and immune evasion. These events include a multitude of biochemical and genetic mechanisms involving both bacterial and host proteins. This review focuses on proteins involved in interactions between B. bacilliformis and human host. Some of them (e.g., flagellin, Brps, IalB, FtsZ, Hbp/Pap31, and other outer membrane proteins) are potential protein antigen candidates for a synthetic vaccine.


Estimating Bighorn Sheep (Ovis Canadensis) Abundance Using Noninvasive Sampling At A Mineral Lick Within A National Park Wilderness Area, Kathryn A. Schoenecker, Mary Kay Watry, Laura E. Ellison, Michael K. Schwartz, Gordon Luikart Aug 2015

Estimating Bighorn Sheep (Ovis Canadensis) Abundance Using Noninvasive Sampling At A Mineral Lick Within A National Park Wilderness Area, Kathryn A. Schoenecker, Mary Kay Watry, Laura E. Ellison, Michael K. Schwartz, Gordon Luikart

Biological Sciences Faculty Publications

Conservation of species requires accurate population estimates. We used genetic markers from feces to determine bighorn sheep abundance for a herd that was hypothesized to be declining and in need of population status monitoring. We sampled from a small but accessible portion of the population's range where animals natural congregate at a natural mineral lick to test whether we could accurately estimate population size by sampling from an area where animals concentrate. We used mark-recapture analysis to derive population estimates, and compared estimates from this smaller spatial sampling to estimates from sampling of the entire bighorn sheep range. We found …


Reproductive Performance Of Kittlitz's Murrelet In A Glaciated Landscape, Icy Bay, Alaska, Usa, Michelle L. Kissling, Scott M. Gende, Stephen B. Lewis, Paul Lukacs Apr 2015

Reproductive Performance Of Kittlitz's Murrelet In A Glaciated Landscape, Icy Bay, Alaska, Usa, Michelle L. Kissling, Scott M. Gende, Stephen B. Lewis, Paul Lukacs

Wildlife Biology Faculty Publications

Kittlitz's Murrelet (Brachyramphus brevirostris) is a dispersed-nesting seabird endemic to Alaska and eastern Russia that may have experienced considerable population declines in some parts of its range in the past few decades. Poor reproduction has been suggested as the demographic bottleneck, yet there are no direct estimates of reproduction in a glaciated area where this species reaches its highest densities at sea during the breeding season. The lack of demographic information in glacial habitats has limited our ability to interpret population trends and to clarify whether the presence of glaciers affects reproductive performance. Between 2007 and 2012, we …


Spatial, Temporal, And Density-Dependent Components Of Habitat Quality For A Desert Owl, Aaron D. Flesch, Richard L. Hutto, Willem J. D. Leeuwen, Kyle Hartfield, Sky Jacobs Mar 2015

Spatial, Temporal, And Density-Dependent Components Of Habitat Quality For A Desert Owl, Aaron D. Flesch, Richard L. Hutto, Willem J. D. Leeuwen, Kyle Hartfield, Sky Jacobs

Biological Sciences Faculty Publications

Spatial variation in resources is a fundamental driver of habitat quality but the realized value of resources at any point in space may depend on the effects of conspecifics and stochastic factors, such as weather, which vary through time. We evaluated the relative and combined effects of habitat resources, weather, and conspecifics on habitat quality for ferruginous pygmy-owls (Glaucidium brasilianum) in the Sonoran Desert of northwest Mexico by monitoring reproductive output and conspecific abundance over 10 years in and around 107 territory patches. Variation in reproductive output was much greater across space than time, and although habitat resources …


The Guanine Nucleotide Exchange Factor Ric-8a Induces Domain Separation And Ras Domain Plasticity In Gαi1, Ned Van Eps, Celestine J. Thomas, Wayne L. Hubbell, Stephen R. Sprang Feb 2015

The Guanine Nucleotide Exchange Factor Ric-8a Induces Domain Separation And Ras Domain Plasticity In Gαi1, Ned Van Eps, Celestine J. Thomas, Wayne L. Hubbell, Stephen R. Sprang

Biological Sciences Faculty Publications

Heterotrimeric G proteins are activated by exchange of GDP for GTP at the G protein alpha subunit (Gα), most notably by G protein-coupled transmembrane receptors. Ric-8A is a soluble cytoplasmic protein essential for embryonic development that acts as both a guanine nucleotide exchange factor (GEF) and a chaperone for Gα subunits of the i, q, and 12/13 classes. Previous studies demonstrated that Ric-8A stabilizes a dynamically disordered state of nucleotide-free Gα as the catalytic intermediate for nucleotide exchange, but no information was obtained on the structures involved or the magnitude of the structural fluctuations. In the present study, site-directed spin …


Low-Severity Fire Increases Tree Defense Against Bark Beetle Attacks, Sharon Metzger Hood, Anna Sala, Emily K. Heyerdahl, Marion Boutin Jan 2015

Low-Severity Fire Increases Tree Defense Against Bark Beetle Attacks, Sharon Metzger Hood, Anna Sala, Emily K. Heyerdahl, Marion Boutin

Biological Sciences Faculty Publications

Induced defense is a common plant strategy in response to herbivory. Although abiotic damage, such as physical wounding, pruning, and heating, can induce plant defense, the effect of such damage by large-scale abiotic disturbances on induced defenses has not been explored and could have important consequences for plant survival facing future biotic disturbances. Historically, low-severity wildfire was a widespread, frequent abiotic disturbance in many temperate coniferous forests. Native Dendroctonus and Ips bark beetles are also a common biotic disturbance agent in these forest types and can influence tree mortality patterns after wildfire. Therefore, species living in these disturbance-prone environments with …


Integrated Survival Analysis Using An Event-Time Approach In A Bayesian Framework, Daniel P. Walsh, Victoria J. Dreitz, Dennis M. Heisey Jan 2015

Integrated Survival Analysis Using An Event-Time Approach In A Bayesian Framework, Daniel P. Walsh, Victoria J. Dreitz, Dennis M. Heisey

Wildlife Biology Faculty Publications

Event-time or continuous-time statistical approaches have been applied throughout the bio-statistical literature and have led to numerous scientific advances. However, these techniques have traditionally relied on knowing failure times. this has limited application of these analyses, particularly, within the ecological field where fates of marked animals may be unknown. To address these limitations, we developed in integrated approach within a Bayesian framework to estimate hazard rates in the face of unknown fates. We combine failure/survival times from individuals whose fates are known and times of which are interval-censored with information from those whose fates are unknown, and model the process …


Population Differentiation And Habitat Selection Of A Montane Red Fox Population In The Greater Yellowstone Ecosystem, Patrick Cross Jan 2015

Population Differentiation And Habitat Selection Of A Montane Red Fox Population In The Greater Yellowstone Ecosystem, Patrick Cross

Graduate Student Theses, Dissertations, & Professional Papers

Montane red fox (Vulpes vulpes) populations across the western United States are genetically and morphologically distinct from foxes at lower elevations. These montane populations also share a preference for subalpine forest habitats. One hypothesis is that they stem from boreal forest-associated ancestors that expanded during the Pleistocene when boreal forests extended farther south than they do today. Forest habitat selection may therefore aid the persistence of native populations surrounded by non-native conspecifics. Alternatively, this behavior may be an avoidance mechanism in response to competition with larger coyotes (Canis latrans), or a product of the fox's natural adaptability. The red fox …


Assessing Changes In Avian Communities, Jessie D. Golding Jan 2015

Assessing Changes In Avian Communities, Jessie D. Golding

Graduate Student Theses, Dissertations, & Professional Papers

Grazing is a potentially powerful tool to address wildlife declines associated with land use conversion in the western United States. Grazing systems can be manipulated to achieve desired vegetation outcomes, preserve native habitat and economically benefit multiple stakeholders. As a result, systems designed to benefit native ecosystems are being widely implemented. However, the benefits of these grazing systems on many wildlife communities remain relatively unexplored. Songbirds provide an ideal study system to test these benefits because they continue to use native habitat that is currently grazed. Given limited time and resources, conservation practitioners often monitor a single focal species or …


Wolf-Cougar Co-Occurrence In The Central Canadian Rocky Mountains, Ellen Brandell Jan 2015

Wolf-Cougar Co-Occurrence In The Central Canadian Rocky Mountains, Ellen Brandell

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Cougars and wolves are top carnivores that influence the dynamics of an ecosystem, including prey behavior and dynamics, and interspecific competition. Studies about the interactions between wolves and cougars typically find wolves are dominant competitors to cougars. We examined single-species, single-season occupancy models and co-occurrence models of wolves and cougars in the Central Canadian Rocky Mountains to understand interactions between these two species on a grand landscape. Data was collected from 2012-2013 using remote wildlife cameras and separated into seasons. Naïve occupancy estimates were larger for wolves in both seasons, but both species had smaller ranges in winter. There were …