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Biological Sciences Faculty Publications

2005

Articles 1 - 30 of 37

Full-Text Articles in Biology

Tracking Changes In Bioavailable Fe Within High-Nitrate Low-Chlorophyll Oceanic Waters: A First Estimate Using A Heterotrophic Bacterial Bioreporter, Robert Michael Mckay, C. E. Mioni, S. M. Handy, M. J. Ellwood, M. R. Twiss, P. W. Boyd, S. W. Wilhelm Dec 2005

Tracking Changes In Bioavailable Fe Within High-Nitrate Low-Chlorophyll Oceanic Waters: A First Estimate Using A Heterotrophic Bacterial Bioreporter, Robert Michael Mckay, C. E. Mioni, S. M. Handy, M. J. Ellwood, M. R. Twiss, P. W. Boyd, S. W. Wilhelm

Biological Sciences Faculty Publications

It is conventional knowledge that heterotrophic bacteria play a key role in the biogeochemical cycling of oceanic carbon. However, only recently has their role in marine iron ( Fe) biogeochemical cycles been examined. Research during this past decade has demonstrated an inextricable link between Fe chemistry and the biota, as >99% of Fe in marine systems is complexed to organic chelates of unknown but obviously biotic origin. Here we present a novel approach to assess and compare Fe bioavailability in low Fe HNLC waters using a bioluminescent bacterial reporter that quantitatively responds to the concentration of bioavailable Fe by producing …

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Impact Of Phytoplankton On The Biogeochemical Cycling Of Iron In Subantarctic Waters Southeast Of New Zealand During Fecycle, Robert Michael Mckay, S. W. Wilhelm, J. Hall, D. A. Hutchins, M. M. D. Al-R Shaidat, C. E. Mioni, S. Pickmere, D. Porta, P. W. Boyd Dec 2005

Impact Of Phytoplankton On The Biogeochemical Cycling Of Iron In Subantarctic Waters Southeast Of New Zealand During Fecycle, Robert Michael Mckay, S. W. Wilhelm, J. Hall, D. A. Hutchins, M. M. D. Al-R Shaidat, C. E. Mioni, S. Pickmere, D. Porta, P. W. Boyd

Biological Sciences Faculty Publications

During austral summer 2003, we tracked a patch of surface water infused with the tracer sulfur hexafluoride, but without addition of Fe, through subantarctic waters over 10 days in order to characterize and quantify algal Fe pools and fluxes to construct a detailed biogeochemical budget. Nutrient profiles characterized this patch as a high-nitrate, low-silicic acid, low-chlorophyll (HNLSiLC) water mass deficient in dissolved Fe. The low Fe condition was confirmed by several approaches: shipboard iron enrichment experiments and physiological indices of Fe deficiency (F(v)/F(m) < 0.25, Ferredoxin Index < 0.2). During FeCycle, picophytoplankton (0.2-2 mu m) and nanophytoplankton (2-20 mu m) each contributed >40% of total chlorophyll. Whereas the picophytoplankton accounted for similar to 50% of total primary production, they …

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Bartonella Bacilliformis Groel: Effect On Growth Of Human Vascular Endothelial Cells In Infected Cocultures, Laura S. Smitherman, Michael F. Minnick Dec 2005

Bartonella Bacilliformis Groel: Effect On Growth Of Human Vascular Endothelial Cells In Infected Cocultures, Laura S. Smitherman, Michael F. Minnick

Biological Sciences Faculty Publications

Bartonella are the only bacteria known to induce angioproliferative lesions of the human vasculature and liver during infection. Previous work from our lab suggests that GroEL participates in the mitogenic response observed in HUVEC cultures supplemented with the soluble fraction of Bartonella bacilliformis. Work in this study shows that exposure to high concentrations of the fraction is actually cytotoxic for HUVECs. To analyze this phenomenon, live B. bacilliformis-HUVEC cocultures were employed to study the effect of excess bacterial GroEL on the host cell during active infection. Four B. bacilliformis strains were generated to produce varying levels of GroEL. HUVEC cocultures …

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Evolution Of Sexual Dimorphism And Male Dimorphism In The Expression Of Beetle Horns: Phylogenetic Evidence For Modularity, Evolutionary Lability, And Constraint, Douglas J. Emlen, John Hunt, Leigh W. Simmons Oct 2005

Evolution Of Sexual Dimorphism And Male Dimorphism In The Expression Of Beetle Horns: Phylogenetic Evidence For Modularity, Evolutionary Lability, And Constraint, Douglas J. Emlen, John Hunt, Leigh W. Simmons

Biological Sciences Faculty Publications

Beetle horns are enlarged outgrowths of the head or thorax that are used as weapons in contests over access to mates. Horn development is typically confined to males (sexual dimorphism) and often only to the largest males (male dimorphism). Both types of dimorphism result from endocrine threshold mechanisms that coordinate cell proliferation near the end of the larval period. Here, we map the presence/absence of each type of dimorphism onto a recent phylogeny for the genus Onthophagits (Coleoptera: Scarabaeidae) to explore how horn development has changed over time. Our results provide empirical support for several recent predictions regarding the evolutionary …

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Changes In Bird Abundance After Wildfire: Importance Of Fire Severity And Time Since Fire, Kristina M. Smucker, Richard L. Hutto, Brian M. Steele Oct 2005

Changes In Bird Abundance After Wildfire: Importance Of Fire Severity And Time Since Fire, Kristina M. Smucker, Richard L. Hutto, Brian M. Steele

Biological Sciences Faculty Publications

Fire can cause profound changes in the composition and abundance of plant and animal species, but logistics, unpredictability of weather, and inherent danger make it nearly impossible to study high-severity fire effects experimentally. We took advantage of a unique opportunity to use a before–after/control–impact (BACI) approach to analyze changes in bird assemblages after the severe fires of 2000 in the Bitterroot Valley, Montana. Observers surveyed birds using 10-minute point counts and collected vegetation data from 13 burned and 13 unburned transects for five years before fire and three years after fire. We compared changes in vegetation variables and relative bird …

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Characterization And Expression Analysis Of The Groesl Operon Of Bartonella Bacilliformis, Julie A. Callison, James M. Battisti, Kate N. Sappington, Laura S. Smitherman, Michael F. Minnick Oct 2005

Characterization And Expression Analysis Of The Groesl Operon Of Bartonella Bacilliformis, Julie A. Callison, James M. Battisti, Kate N. Sappington, Laura S. Smitherman, Michael F. Minnick

Biological Sciences Faculty Publications

The groESL operon of Bartonella bacilliformis, a facultative intracellular, Gram-negative bacterium and etiologic agent of Oroya Fever, was characterized. Sequence analysis revealed an operon containing two genes of 294 (groES) and 1632 nucleotides (groEL) separated by a 55-nt intergenic spacer. The operon is preceded by a 72-nt ORF (ORF1) that encodes a hypothetical protein with homology to a portion of the HrcA repressor for groESL. A divergent fumarate hydratase C (fumC) gene lies further upstream. Deduced amino acid sequences for B. bacilliformis GroEL and GroES revealed a high degree of identity with homologues from other Bartonella and alpha-Protebacteria. A single …

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Parc Mutations In Fluoroquinolone-Resistant Borrelia Burgdorfeti, Kendal M. Galbraith, Amanda C. Ng, Betsy J. Eggers, Craig R. Kuchel, Christian H. Eggers, D. Scott Samuels Oct 2005

Parc Mutations In Fluoroquinolone-Resistant Borrelia Burgdorfeti, Kendal M. Galbraith, Amanda C. Ng, Betsy J. Eggers, Craig R. Kuchel, Christian H. Eggers, D. Scott Samuels

Biological Sciences Faculty Publications

We have isolated in vitro fluoroquinolone-resistant mutants of the Lyme disease agent, Borrelia burgdorferi. Mutations in parC, which encodes a subunit of topoisomerase IV, were associated with loss of susceptibility to sparfloxacin, moxifloxacin, and Bay-Y3118, but not ciprofloxacin. This is the first description of fluoroquinolone resistance in the spirochete phylum.

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A Peptide Core Motif For Binding To Heterotrimeric G Protein Alpha Subunits, William W. Ja, Anirban Adhikari, Ryan J. Austin, Stephen R. Sprang, Richard W. Roberts Sep 2005

A Peptide Core Motif For Binding To Heterotrimeric G Protein Alpha Subunits, William W. Ja, Anirban Adhikari, Ryan J. Austin, Stephen R. Sprang, Richard W. Roberts

Biological Sciences Faculty Publications

Recently, in vitro selection using mRNA display was used to identify a novel peptide sequence that binds with high affinity to Galpha(i1). The peptide was minimized to a 9-residue sequence (R6A-1) that retains high affinity and specificity for the GDP-bound state of Galpha(i1) and acts as a guanine nucleotide dissociation inhibitor (GDI). Here we demonstrate that the R6A-1 peptide interacts with Galpha subunits representing all four G protein classes, acting as a core motif for Galpha interaction. This contrasts with the consensus G protein regulatory(GPR) sequence, a 28-mer peptide GDI derived from the GoLoco (Galpha(i/0)-Loco interaction)/GPR motif that shares no …

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Evolution Of Morphological Integration: Developmental Accommodation Of Stress-Induced Variation, Alexander V. Badyaev, Kerry R. Foresman, Rebecca L. Young Sep 2005

Evolution Of Morphological Integration: Developmental Accommodation Of Stress-Induced Variation, Alexander V. Badyaev, Kerry R. Foresman, Rebecca L. Young

Biological Sciences Faculty Publications

Extreme environmental change during growth often results in an increase in developmental abnormalities in the morphology of an organism. The evolutionary significance of such stress-induced variation depends on the recurrence of a stressor and on the degree to which developmental errors can be accommodated by an organism's ontogeny without significant loss of function. We subjected populations of four species of soricid shrews to an extreme environment during growth and measured changes in the patterns of integration and accommodation of stress-induced developmental errors in a complex of mandibular traits. Adults that grew under an extreme environment had lower integration of morphological …

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Structural And Molecular Characterization Of A Preferred Protein Interaction Surface On G Protein Beta Gamma Subunits, Tara L. Davis, Tabetha M. Bonacci, Stephen R. Sprang, Alan V. Smrcka Aug 2005

Structural And Molecular Characterization Of A Preferred Protein Interaction Surface On G Protein Beta Gamma Subunits, Tara L. Davis, Tabetha M. Bonacci, Stephen R. Sprang, Alan V. Smrcka

Biological Sciences Faculty Publications

G protein betagamma subunits associate with many binding partners in cellular signaling cascades. In previous work, we used random-peptide phage display screening to identify a diverse family of peptides that bound to a common surface on Gbetagamma subunits and blocked a subset of Gbetagamma effectors. Later studies showed that one of the peptides caused G protein activation through a novel Gbetagamma-dependent, nucleotide exchange-independent mechanism. Here we report the X-ray crystal structure of Gbeta(1)gamma(2) bound to this peptide, SIGK (SIGKAFKILGYPDYD), at 2.7 A resolution. SIGK forms a helical structure that binds the same face of Gbeta(1) as the switch II region …

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Implications Of Spatial Autocorrelation And Dispersal For The Modeling Of Species Distributions, Volker Bahn Aug 2005

Implications Of Spatial Autocorrelation And Dispersal For The Modeling Of Species Distributions, Volker Bahn

Biological Sciences Faculty Publications

Modeling the geographical distributions of wildlife species is important for ecology and conservation biology. Spatial autocorrelation in species distributions poses a problem for distribution modeling because it invalidates the assumption of independence among sample locations. I explored the prevalence and causes of spatial autocorrelation in data from the Breeding Bird Survey, covering the conterminous United States, using Regression Trees, Conditional Autoregressive Regressions (CAR), and the partitioning of variance. I also constructed a simulation model to investigate dispersal as a process contributing to spatial autocorrelation, and attempted to verify the connection between dispersal and spatial autocorrelation in species’ distributions in empirical …

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Human Activity Mediates A Trophic Cascade Caused By Wolves, Mark Hebblewhite, Clifford A. White, Clifford G. Nietvelt, John A. Mckenzie, Tomas E. Hurd, John M. Fryxell, Suzanne E. Bayley, Paul C. Paquet Aug 2005

Human Activity Mediates A Trophic Cascade Caused By Wolves, Mark Hebblewhite, Clifford A. White, Clifford G. Nietvelt, John A. Mckenzie, Tomas E. Hurd, John M. Fryxell, Suzanne E. Bayley, Paul C. Paquet

Biological Sciences Faculty Publications

Experimental evidence of trophic cascades initiated by large vertebrate predators is rare in terrestrial ecosystems. A serendipitous natural experiment provided an opportunity to test the trophic cascade hypothesis for wolves (Canis lupus) in Banff National Park, Canada. The first wolf pack recolonized the Bow Valley of Banff National Park in 1986. High human activity partially excluded wolves from one area of the Bow Valley (low-wolf area), whereas wolves made full use of an adjacent area (high-wolf area). We investigated the effects of differential wolf predation between these two areas on elk (Cervus elaphus) population density, adult …

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Using Airborne Multispectral Imagery To Evaluate Geomorphic Work Across Floodplains Of Gravel-Bed Rivers, M. S. Lorang, D. C. Whited, Richard F. Hauer, J. S. Kimball, Jack Arthur Stanford Aug 2005

Using Airborne Multispectral Imagery To Evaluate Geomorphic Work Across Floodplains Of Gravel-Bed Rivers, M. S. Lorang, D. C. Whited, Richard F. Hauer, J. S. Kimball, Jack Arthur Stanford

Biological Sciences Faculty Publications

Fluvial processes of cut and fill alluviation and channel abandonment or avulsion are essential for maintaining the ecological health of floodplain ecosystems characteristic of gravel-bed rivers. These dynamic processes shape the floodplain landscape, resulting in a shifting mosaic of habitats, both above and below ground. We present a new and innovative methodology to quantitatively assess the geomorphic work potential necessary to maintain a shifting habitat mosaic for gravel-bed river floodplains. This approach can be used to delineate critical habitats for preservation through land acquisition and conservation easements, often critical elements of river restoration plans worldwide. Spatially explicit modeling of water …

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Unpalatable Plants Protect Neighbors From Grazing And Increase Plant Community Diversity, Ragan M. Callaway, David Kikodze, Marina Chiboshvili, Liana Khetsuriani Jul 2005

Unpalatable Plants Protect Neighbors From Grazing And Increase Plant Community Diversity, Ragan M. Callaway, David Kikodze, Marina Chiboshvili, Liana Khetsuriani

Biological Sciences Faculty Publications

Tasty plants can be protected from herbivores by unpalatable neighbors. We used experimental exclosures, removal of unpalatable species, and transplants of palatable and unpalatable species in subalpine meadows of the Caucasus Mountains of Georgia to study the effects of two unpalatable species on plant communities. We found that Cirsium obalatum and Veratrum lobelianum, two large native perennial herbs that invade after heavy grazing, had strong facilitative effects on communities through their indirect effects on livestock herbivores. These unpalatable invaders had different effects on community composition when livestock were present than when livestock were excluded. Furthermore, removing Cirsium and Veratrum …

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Analysis Of The Ospc Regulatory Element Controlled By The Rpon-Rpos Regulatory Pathway In Borrelia Burgdorferi, Xiaofeng F. Yang, Meghan C. Lybecker, Utpal Pal, Sophie M. Alani, Jon Blevins, Andrew T. Revel, D. Scott Samuels Jul 2005

Analysis Of The Ospc Regulatory Element Controlled By The Rpon-Rpos Regulatory Pathway In Borrelia Burgdorferi, Xiaofeng F. Yang, Meghan C. Lybecker, Utpal Pal, Sophie M. Alani, Jon Blevins, Andrew T. Revel, D. Scott Samuels

Biological Sciences Faculty Publications

Outer surface lipoprotein C (OspC) is a key virulence factor of Borrelia burgdorferi. ospC is differentially regulated during borrelial transmission from ticks to rodents, and such regulation is essential for maintaining the spirochete in its natural enzootic cycle. Recently, we showed that the expression of ospC in B. burgdorferi is governed by a novel alternative sigma factor regulatory network, the RpoN-RpoS pathway. However, the precise mechanism by which the RpoN-RpoS pathway controls ospC expression has been unclear. In particular, there has been uncertainty regarding whether ospC is controlled directly by RpoS (sigma(s)) or indirectly through a transactivator (induced by RpoS). …

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Evaluating Forensic Dna Evidence, Dan E. Krane, William C. Thompson Jun 2005

Evaluating Forensic Dna Evidence, Dan E. Krane, William C. Thompson

Biological Sciences Faculty Publications

No abstract provided.

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Stress Tolerance And Competitive-Response Ability Determine The Outcome Of Biotic Interactions, Pierre Liancourt, Ragan M. Callaway, Richard Michalet Jun 2005

Stress Tolerance And Competitive-Response Ability Determine The Outcome Of Biotic Interactions, Pierre Liancourt, Ragan M. Callaway, Richard Michalet

Biological Sciences Faculty Publications

Theoretical models predict that the net outcome of biotic interactions among plants is the sum of co-occurring negative and positive interactions, with facilitation generally increasing in importance with increasing abiotic stress. However, species differ in fundamental niche optima; thus the intensity of stress is relative among species and important only in the context of these relative differences. We tested the hypothesis that the facilitative response of a species is relative to how much abiotic conditions deviate from the optimum conditions for that particular species (stress), and the competitive “response” ability of the species (i.e., its ability to tolerate the inhibitory …

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Linking Patterns And Processes In Alpine Plant Communities: A Global Study, Zaal Kikvidze, Francisco I. Pugnaire, Robin W. Brooker, Philippe Choler, Christopher J. Lortie, Richard Michalet, Ragan M. Callaway Jun 2005

Linking Patterns And Processes In Alpine Plant Communities: A Global Study, Zaal Kikvidze, Francisco I. Pugnaire, Robin W. Brooker, Philippe Choler, Christopher J. Lortie, Richard Michalet, Ragan M. Callaway

Biological Sciences Faculty Publications

Predictable relationships among patterns, processes, and properties of plant communities are crucial for developing meaningful conceptual models in community ecology. We studied such relationships in 18 plant communities spread throughout nine Northern Hemisphere high-mountain subalpine and alpine meadow systems and found linear and curvilinear correlative links among temperature, precipitation, productivity, plant interactions, spatial pattern, and richness. We found that sites with comparatively mild climates have greater plant biomass, and at these sites strong competition corresponds with overdispersed distribution of plants, reducing intraspecific patchiness and in turn increasing local richness. Sites with cold climates have little biomass, and at these sites …

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Geography Of Spring Landbird Migration Through Riparian Habitats In Southwestern North America, Susan K. Skagen, Jeffrey F. Kelly, Charles Van Riper Iii, Richard L. Hutto, Deborah M. Finch, David J. Krueper, Cynthia P. Melcher May 2005

Geography Of Spring Landbird Migration Through Riparian Habitats In Southwestern North America, Susan K. Skagen, Jeffrey F. Kelly, Charles Van Riper Iii, Richard L. Hutto, Deborah M. Finch, David J. Krueper, Cynthia P. Melcher

Biological Sciences Faculty Publications

Migration stopover resources, particularly riparian habitats, are critically important to landbirds migrating across the arid southwestern region of North America. To explore the effects of species biogeography and habitat affinity on spring migration patterns, we synthesized existing bird abundance and capture data collected in riparian habitats of the borderlands region of the U.S. and Mexico. We determined the importance of geographic factors (longitude and latitude) in explaining variation in abundances and capture rates of 32 long-distance and three short-distance migrant species. Abundances and capture rates of 13 and 11 species, respectively, increased with increasing longitude, and four species' abundance and …

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An East-West Comparison Of Migration In North American Wood Warblers, Jeffrey F. Kelly, Richard L. Hutto May 2005

An East-West Comparison Of Migration In North American Wood Warblers, Jeffrey F. Kelly, Richard L. Hutto

Biological Sciences Faculty Publications

That western and eastern songbird migration routes are distinct ecological systems has been proposed for over 100 years. Nonetheless, this distinction has not been widely recognized nor have there been any comparative studies that quantitatively evaluate the differences and similarities between western and eastern songbird migration systems. We drew from previously published research on wood warblers to highlight patterns in stopover ecology that suggest fundamental differences between western and eastern migrants. In particular, we compared biogeography, evolutionary relationships, and stopover ecology of wood warblers from western and eastern North America and found: (1) multiple lines of evidence that indicate western …

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Targeting Of Arf-1 To The Early Golgi By Membrin, An Er-Golgi Snare, Akira Honda, Omayma S. Al-Awar, Jesse C. Hay, Julie G. Donaldson Mar 2005

Targeting Of Arf-1 To The Early Golgi By Membrin, An Er-Golgi Snare, Akira Honda, Omayma S. Al-Awar, Jesse C. Hay, Julie G. Donaldson

Biological Sciences Faculty Publications

Arf and Rab family GTPases regulate membrane traffic in cells, yet little is known about how they are targeted to distinct organelles. To identify sequences in Arf-1 necessary for Golgi targeting, we examined the localization of chimeras between Arf-1 and Arf-6. Here, we identify a 16-amino acid sequence in Arf-1 that specifies Golgi targeting and contains a motif (MXXE) that is important for Arf-1 binding to membrin, an ER-Golgi SNARE protein. The MXXE motif is conserved in all Arfs known to localize to the Golgi and enables Arf-1 to localize to the early Golgi. Arf-1 lacking these 16 aa can …

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Structural Basis For The Inhibition Of Mammalian Membrane Adenylyl Cyclase By 2 '(3')-O-(N-Methylanthraniloyl)-Guanosine 5 '-Triphosphate, Tung-Chung Mou, Andreas Gille, David A. Fancy, Roland Seifert, Stephen R. Sprang Feb 2005

Structural Basis For The Inhibition Of Mammalian Membrane Adenylyl Cyclase By 2 '(3')-O-(N-Methylanthraniloyl)-Guanosine 5 '-Triphosphate, Tung-Chung Mou, Andreas Gille, David A. Fancy, Roland Seifert, Stephen R. Sprang

Biological Sciences Faculty Publications

Membrane-bound mammalian adenylyl cyclase (mAC) catalyzes the synthesis of intracellular cyclic AMP from ATP and is activated by stimulatory G protein alpha subunits (Galpha(s)) and by forskolin (FSK). mACs are inhibited with high potency by 2 '(3')-O-(N-methylanthraniloyl) (MANT)-substituted nucleotides. In this study, the crystal structures of the complex between Galpha(s).GTPgammaS and the catalytic C1 and C2 domains from type V and type II mAC (VC1.IIC2), bound to FSK and either MANT-GTP.Mg(2+) or MANT-GTP.Mn(2+) have been determined. MANT-GTP coordinates two metal ions and occupies the same position in the catalytic site as P-site inhibitors and substrate analogs. However, the orientation of …

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Origin Of Asymmetry In Adenylyl Cyclases: Structures Of Mycobacterium Tuberculosis Rv1900c, Sangita C. Sinha, Martina Wetterer, Stephen R. Sprang, Joachim E. Schultz, Jürgen U. Linder Feb 2005

Origin Of Asymmetry In Adenylyl Cyclases: Structures Of Mycobacterium Tuberculosis Rv1900c, Sangita C. Sinha, Martina Wetterer, Stephen R. Sprang, Joachim E. Schultz, Jürgen U. Linder

Biological Sciences Faculty Publications

Rv1900c, a Mycobacterium tuberculosis adenylyl cyclase, is composed of an N-terminal alpha/beta-hydrolase domain and a C-terminal cyclase homology domain. It has an unusual 7% guanylyl cyclase side-activity. A canonical substrate-defining lysine and a catalytic asparagine indispensable for mammalian adenylyl cyclase activity correspond to N342 and H402 in Rv1900c. Mutagenic analysis indicates that these residues are dispensable for activity of Rv1900c. Structures of the cyclase homology domain, solved to 2.4 A both with and without an ATP analog, form isologous, but asymmetric homodimers. The noncanonical N342 and H402 do not interact with the substrate. Subunits of the unliganded open dimer move …

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Phylogenetic Reconstruction Of Exoristinae Using Molecular Data: A Bayesian Re-Analysis, John O. Stireman Iii Feb 2005

Phylogenetic Reconstruction Of Exoristinae Using Molecular Data: A Bayesian Re-Analysis, John O. Stireman Iii

Biological Sciences Faculty Publications

A few years ago I published the results of a phylogenetic analysis of New World Exoristinae based on molecular data from two genes, 28S rDNA and Elongation Factor 1-alpha (Stireman 2002). In that study I employed parsimony, neighbor joining, and maximum likelihood inference methods to generate phylogenetic reconstructions, and explored a variety of weighting schemes and combinations of the sequence data (i.e. each gene separately and both together). The results of these analyses generally supported recent taxonomic hypotheses (e.g., Herting 1984; Wood 1987; O’Hara and Wood 2004). For example, Tachinidae and Exoristinae were reconstructed as monophyletic in most analyses, as …

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Structure Of The P115rhogef Rgrgs Domain-Galpha13/I1 Chimera Complex Suggests Convergent Evolution Of A Gtpase Activator, Zhe Chen, William D. Singer, Paul C. Sternweis, Stephen R. Sprang Feb 2005

Structure Of The P115rhogef Rgrgs Domain-Galpha13/I1 Chimera Complex Suggests Convergent Evolution Of A Gtpase Activator, Zhe Chen, William D. Singer, Paul C. Sternweis, Stephen R. Sprang

Biological Sciences Faculty Publications

p115RhoGEF, a guanine nucleotide exchange factor (GEF) for Rho GTPase, is also a GTPase-activating protein (GAP) for G12 and G13 heterotrimeric Galpha subunits. The GAP function of p115RhoGEF resides within the N-terminal region of p115RhoGEF (the rgRGS domain), which includes a module that is structurally similar to RGS (regulators of G-protein signaling) domains. We present here the crystal structure of the rgRGS domain of p115RhoGEF in complex with a chimera of Galpha13 and Galphai1. Two distinct surfaces of rgRGS interact with Galpha. The N-terminal betaN-alphaN hairpin of rgRGS, rather than its RGS module, forms intimate contacts with the catalytic site …

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The Genetics Of Ray Pattern Variation In Caenorhabditis Briggsae, Scott Everet Baird, Cynthia R. Davidson, Justin C. Bohrer Jan 2005

The Genetics Of Ray Pattern Variation In Caenorhabditis Briggsae, Scott Everet Baird, Cynthia R. Davidson, Justin C. Bohrer

Biological Sciences Faculty Publications

Background: How does intraspecific variation relate to macroevolutionary change in morphology? This question can be addressed in species in which derived characters are present but not fixed. In rhabditid nematodes, the arrangement of the nine bilateral pairs of peripheral sense organs (rays) in tails of males is often the most highly divergent character between species. The development of ray pattern involves inputs from hometic gene expression patterns, TGFβ signalling, Wnt signalling, and other genetic pathways. In Caenorhabditis briggsae, strain-specific variation in ray pattern has provided an entrée into the evolution of ray pattern. Some strains were fixed for a derived …

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Fecycle: Attempting An Iron Biogeochemical Budget From A Mesoscale Sf6 Tracer Experiment In Unperturbed Low Iron Waters, Robert Michael Mckay, P. W. Boyd, C. S. Law, D. A. Hutchins, E. R. Abraham, P. L. Croot, M. Ellwood, R. D. Frew, M. Hadfield, J. Hall, S. Handy, C. Hare, J. Higgins, P. Hill, K. A. Hunter, K. Leblanc, M. T. Maldonado, C. Mioni, M. Oliver, S. Pickmere, M. Pinkerton, K. Safi, S. Sander, S. A. Sanudo-Wilhelmy, M. Smith, R. Strzepek, A. Tovar-Sanchez, S. W. Wilhelm Jan 2005

Fecycle: Attempting An Iron Biogeochemical Budget From A Mesoscale Sf6 Tracer Experiment In Unperturbed Low Iron Waters, Robert Michael Mckay, P. W. Boyd, C. S. Law, D. A. Hutchins, E. R. Abraham, P. L. Croot, M. Ellwood, R. D. Frew, M. Hadfield, J. Hall, S. Handy, C. Hare, J. Higgins, P. Hill, K. A. Hunter, K. Leblanc, M. T. Maldonado, C. Mioni, M. Oliver, S. Pickmere, M. Pinkerton, K. Safi, S. Sander, S. A. Sanudo-Wilhelmy, M. Smith, R. Strzepek, A. Tovar-Sanchez, S. W. Wilhelm

Biological Sciences Faculty Publications

An improved knowledge of iron biogeochemistry is needed to better understand key controls on the functioning of high-nitrate low-chlorophyll (HNLC) oceanic regions. Iron budgets for HNLC waters have been constructed using data from disparate sources ranging from laboratory algal cultures to ocean physics. In summer 2003 we conducted FeCycle, a 10-day mesoscale tracer release in HNLC waters SE of New Zealand, and measured concurrently all sources (with the exception of aerosol deposition) to, sinks of iron from, and rates of iron recycling within, the surface mixed layer. A pelagic iron budget (timescale of days) indicated that oceanic supply terms (lateral …

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Vertebrate Gld2 Poly(A) Polymerases In The Germline And The Brain, Labib Rouhana, Liaoteng Wang, Natascha Buter, Jae Eun Kwak, Craig A. Schiltz, Tania Gonzalez, Ann E. Kelley, Charles F. Landry, Marvin Wickens Jan 2005

Vertebrate Gld2 Poly(A) Polymerases In The Germline And The Brain, Labib Rouhana, Liaoteng Wang, Natascha Buter, Jae Eun Kwak, Craig A. Schiltz, Tania Gonzalez, Ann E. Kelley, Charles F. Landry, Marvin Wickens

Biological Sciences Faculty Publications

Cytoplasmic polyadenylation is important in the control of mRNA stability and translation, and for early animal development and synaptic plasticity. Here, we focus on vertebrate poly(A) polymerases that are members of the recently described GLD2 family. We identify and characterize two closely related GLD2 proteins in Xenopus oocytes, and show that they possess PAP activity in vivo and in vitro and that they bind known polyadenylation factors and mRNAs known to receive poly(A) during development. We propose that at least two distinct polyadenylation complexes exist in Xenopus oocytes, one of which contains GLD2; the other, maskin and Pumilio. GLD2 protein …

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Monitoring For Adaptive Management In Coniferous Forests Of The Northern Rockies, Jock S. Young, John R. Hoffland, Richard L. Hutto Jan 2005

Monitoring For Adaptive Management In Coniferous Forests Of The Northern Rockies, Jock S. Young, John R. Hoffland, Richard L. Hutto

Biological Sciences Faculty Publications

Monitoring can and should be much more than the effort to track population trends; it can be a proactive effort to understand the effects of human activities on bird populations. It should be an integral part of the adaptive management process. With this in mind, the Northern Region Landbird Monitoring Program has a dual focus: (1) to monitor long-term bird population trends, and (2) to study bird-habitat relationships and management effects. By conducting permanent, longterm monitoring transects every other year, we are free to use the intervening years to study the effects of specific management activities. The coordination and funding …

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Fire On The Mountain: Birds And Burns In The Rocky Mountains, Natasha B. Kotliar, Victoria A. Saab, Richard L. Hutto Jan 2005

Fire On The Mountain: Birds And Burns In The Rocky Mountains, Natasha B. Kotliar, Victoria A. Saab, Richard L. Hutto

Biological Sciences Faculty Publications

No abstract provided.

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