Biology Commons^™

Causes And Consequences Of Prolonged Dormancy For An Iteroparous Geophyte, Silene Spaldingii, Peter Lesica, Elizabeth E. Crone

Biological Sciences Faculty Publications

1. Prolonged dormancy, during which a plant does not produce above-ground shoots during one or more growing seasons, is common in temperate herbaceous species, but its role in life history is poorly understood.

2. We analysed stage transitions to determine the consequences of prolonged dormancy for Silene spaldingii, a perennial geophyte of semi-arid grasslands in the Columbia Basin of western North America. We monitored 179 S. spaldingii plants from 1987 through 2005, and analysed demographic rates as a function of plant state and seasonal precipitation.

3. Dormant plants had similar survival and growth to vegetative plants, and were more …

Conditions For Caribou Persistence In The Wolf-Elk-Caribou Systems Of The Canadian Rockies, Mark Hebblewhite, Jesse Whittington, Mark Bradley, Geoff Skinner, Alan Dibb, Clifford A. White

Biological Sciences Faculty Publications

Woodland caribou populations are considered threatened in Alberta and have declined in the Canadian Rocky Mountain National Parks of Banff and Jasper despite protection from factors causing caribou populations to decline outside of parks. Recent research emphasizes the importance of the numeric response of wolves to moose in moose-caribou-wolf systems to caribou persistence. Moose are rare in the Canadian Rockies, where the dominant ungulate prey for wolves is elk. Few studies have explored wolf-elk dynamics and none have examined implications for caribou. We used data collected in Banff to estimate the numeric response of wolves to elk from 1985 to …

Desulfosporosinus Lacus Sp. Nov., A Sulfate-Reducing Bacterium Isolated From Pristine Freshwater Lake Sediments, S. Ramamoorthy, H. Sass, H. Langner, P. Schumann, R. M. Kroppenstedt, S. Spring, J. Overmann, R. Frank Rosenzweig

Biological Sciences Faculty Publications

A novel sulfate-reducing bacterium was isolated from pristine sediments of Lake Stechlin, Germany. This strain, STP12 , was found to contain predominantly c-type cytochromes and to reduce sulfate, sulfite and thiosulfate using lactate as an electron donor. Although STP12 could not utilize elemental sulfur as an electron acceptor, it could support growth by dissimilatory Fe(III) reduction. In a comparison of 16S rRNA gene sequences, STP12 was 96.7 % similar to Desulfosporosinus auripigmenti DSM 13351 , 96.5 % similar to Desulfosporosinus meridiei DSM 13257 and 96.4 % similar to Desulfosporosinus orientis DSM 765 . DNA-DNA hybridization experiments revealed that strain STP12 …

The Effects Of Postfire Salvage Logging On Cavity-Nesting Birds, Richard L. Hutto, Susan M. Gallo

Biological Sciences Faculty Publications

We investigated the effects of postfire salvage logging on cavity-nesting birds by comparing nest densities and patterns of nest reuse over a three-year period in seven logged and eight unlogged patches of mixed-conifer forest in the Blackfoot-Clearwater Wildlife Management Area, Montana. We found 563 active nests of 18 cavity-nesting birds; all species were found nesting in the uncut burned forest plots, but only eight nested in the salvage-logged plots. All except one species nested at a higher density in the unlogged areas, and half of the species were significantly more abundant in the unlogged plots. Every timber-drilling and timber-gleaning species …

Oligomerization Of Hepatitis C Virus Core Protein Is Crucial For Interaction With The Cytoplasmic Domain Of E1 Envelope Protein, Kousuke Nakai, Toru Okamoto, Tomomi Kimura-Someya, Koji Ishii, Chang Kweng Lim, Hideki Tani, Eiko Matsuo, Takayuki Abe, Yoshio Mori, Tetsuro Suzuki, Tatsuo Miyamura, Jack H. Nunberg, Kohji Moriishi, Yoshiharu Matsuura

Biological Sciences Faculty Publications

Hepatitis C virus (HCV) contains two membrane-associated envelope glycoproteins, E1 and E2, which assemble as a heterodimer in the endoplasmic reticulum (ER). In this study, predictive algorithms and genetic analyses of deletion mutants and glycosylation site variants of the E1 glycoprotein were used to suggest that the glycoprotein can adopt two topologies in the ER membrane: the conventional type I membrane topology and a polytopic topology in which the protein spans the ER membrane twice with an intervening cytoplasmic loop (amino acid residues 288 to 360). We also demonstrate that the E1 glycoprotein is able to associate with the HCV …

Consumers Limit The Abundance And Dynamics Of A Perennial Shrub With A Seed Bank, Matthew J. Kauffman, John L. Maron

Biological Sciences Faculty Publications

For nearly 30 years, ecologists have argued that predators of seeds and seedlings seldom have population-level effects on plants with persistent seed banks and density-dependent seedling survival. We parameterized stage-based population models that incorporated density dependence and seed dormancy with data from a 5.5-year experiment that quantified how granivorous mice and herbivorous voles influence bush lupine (Lupinus arboreus) demography. We asked how seed dormancy and density-dependent seedling survival mediate the impacts of these consumers in dune and grassland habitats. In dune habitat, mice reduced analytical lambda (the intrinsic rate of population growth) by 39%, the equilibrium number of above-ground plants …

Frequent Fire Alters Nitrogen Transformations In Ponderosa Pine Stands Of The Inland Northwest, Thomas H. Gremer, Anna Sala

Biological Sciences Faculty Publications

Recurrent, low-severity fire in ponderosa pine (Pinus ponderosa)linterior Douglas-fir (Pseudotsuga menziesii var. glauca) forests is thought to have directly influenced nitrogen (N) cycling and availability. However, no studies to date have investigated the influence of natural fire intervals on soil processes in undisturbed forests, thereby limiting our ability to understand ecological processes and successional dynamics in this important ecosystem of the Rocky Mountain West. Here, we tested the standing hypothesis that recurrent fire in ponderosa pine/Douglas-fir forests of the Inland Northwest decreases total soil N, but increases N turnover and nutrient availability. We compared soils in stands unburned over the …

Invasion Through Quantitative Effects: Intense Shade Drives Native Decline And Invasive Success, Kurt O. Reinhart, Julie Gurnee, Reyes Tirado, Ragan M. Callaway

Biological Sciences Faculty Publications

The effects of invasive nonnative species on community composition are well documented. However, few studies have determined the mechanisms by which invaders drive these changes. The literature indicates that many nonnative plant species alter light availability differently than natives in a given community, suggesting that shading may be such a mechanism. We compared light quantity (photosynthetically active radiation, PAR) and quality (red : far-red ratio, R:Fr) in riparian reaches heavily invaded by a nonnative tree (Acer platanoides) to that in an uninvaded forest and experimentally tested the effects of our measured differences in PAR and R:Fr on the …

Broad Specificity Of Mammalian Adenylyl Cyclase For Interaction With 2',3'-Substituted Purine- And Pyrimidine Nucleotide Inhibitors, Tung-Chung Mou, Andreas Gille, Srividya Suryanarayana, Mark Richter, Roland Seifert, Stephen R. Sprang

Biological Sciences Faculty Publications

Membrane adenylyl cyclases (mACs) play an important role in signal transduction and are therefore potential drug targets. Earlier, we identified 2',3'-O-(N-methylanthraniloyl) (MANT)-substituted purine nucleotides as a novel class of highly potent competitive mAC inhibitors (Ki values in the 10 nM range). MANT nucleotides discriminate among various mAC isoforms through differential interactions with a binding pocket localized at the interface between the C1 and C2 domains of mAC. In this study, we examine the structure/activity relationships for 2',3'-substituted nucleotides and compare the crystal structures of mAC catalytic domains (VC1:IIC2) bound to MANT-GTP, MANT-ATP, and 2',3'-(2,4,6-trinitrophenyl) (TNP)-ATP. TNP-substituted purine and pyrimidine nucleotides …

Molecular Population Genetics And Phenotypic Diversification Of Two Populations Of The Thermophilic Cyanobacterium Mastigocladus Laminosus, Scott R. Miller, Michael D. Purugganan, Stephanie E. Curtis

Biological Sciences Faculty Publications

We investigated the distributions of genetic and phenotypic variation for two Yellowstone National Park populations of the heterocyst-forming cyanobacterium Mastigocladus (Fischerella) laminosus that exhibit dramatic phenotypic differences as a result of environmental differences in nitrogen availability. One population develops heterocysts and fixes nitrogen in situ in response to a deficiency of combined nitrogen in its environment, whereas the other population does neither due to the availability of a preferred nitrogen source. Slowly evolving molecular markers, including the 16S rRNA gene and the downstream internal transcribed spacer, are identical among all laboratory isolates from both populations but belie considerable genetic and …

Role Of The Stable Signal Peptide Of Junín Arenavirus Envelope Glycoprotein In Ph-Dependent Membrane Fusion, Joanne York, Jack H. Nunberg

Biological Sciences Faculty Publications

The envelope glycoprotein of the arenaviruses (GP-C) is unusual in that the mature complex retains the cleaved, 58-amino-acid signal peptide. Association of this stable signal peptide (SSP) has been shown to be essential for intracellular trafficking and proteolytic maturation of the GP-C complex. We identify here a specific and previously unrecognized role of SSP in pH-dependent membrane fusion. Amino acid substitutions that alter the positive charge at lysine K33 in SSP affect the ability of GP-C to mediate cell-cell fusion and the threshold pH at which membrane fusion is triggered. Based on the presumed location of K33 at or near …

Disturbance Facilitates Invasion: The Effects Are Stronger Abroad Than At Home, José L. Hierro, Diego Villarreal, Özkan Eren, Jon M. Graham, Ragan M. Callaway

Biological Sciences Faculty Publications

Disturbance is one of the most important factors promoting exotic invasion. However, if disturbance per se is sufficient to explain exotic success, then "invasion" abroad should not differ from "colonization" at home. Comparisons of the effects of disturbance on organisms in their native and introduced ranges are crucial to elucidate whether this is the case; however, such comparisons have not been conducted. We investigated the effects of disturbance on the success of Eurasian native Centaurea solstitialis in two invaded regions, California and Argentina, and one native region, Turkey, by conducting field experiments consisting of simulating different disturbances and adding locally …

Mbet3p Is Required For Homotypic Copii Vesicle Tethering In Mammalian Cells, Sidney Yu, Ayano Satoh, Marc Pypaert, Karl Mullen, Jesse C. Hay, Susan Ferro-Novick

Biological Sciences Faculty Publications

TRAPPI is a large complex that mediates the tethering of COPII vesicles to the Golgi (heterotypic tethering) in the yeast Saccharomyces cerevisiae. In mammalian cells, COPII vesicles derived from the transitional endoplasmic reticulum (tER) do not tether directly to the Golgi, instead, they appear to tether to each other ( homotypic tethering) to form vesicular tubular clusters (VTCs). We show that mammalian Bet3p (mBet3p), which is the most highly conserved TRAPP subunit, resides on the tER and adjacent VTCs. The inactivation of mBet3p results in the accumulation of cargo in membranes that colocalize with the COPII coat. Furthermore, using an …