Digital Commons Network^™

Grizzly Bear Digging: Effects On Subalpine Meadow Plants In Relation To Mineral Nitrogen Availability, Sandra E. Tardiff, Jack Arthur Stanford

Biological Sciences Faculty Publications

Grizzly bears (Ursus arctos horribilis) affect plant distributions and mineral nitrogen availability when they forage by digging for the bulbs of glacier lilies (Erythronium grandiflorum) growing in subalpine meadows of Glacier National Park, Montana, United States. Our working hypothesis is that grizzly bears structure plant communities and influence nitrogen availability when they selectively dig for preferred plants. In this paper, we report on differences found in recently disturbed digs (<5 yr old) when compared to adjacent, undisturbed meadow.

We used ion exchange resin bags to determine the availability of mineral nitrogen in grizzly bear digs compared to undisturbed meadow. Soil in digs contained significantly …

Effective Recovery Of Bacterial Dna And Percent-Guanine-Plus-Cytosine-Based Analysis Of Community Structure In The Gastrointestinal Tract Of Broiler Chickens, Juha H. A. Apajalahti, Laura K. Särkilahti, Brita R. E. Mäki, J. Pekka Heikkinen, Päivi H. Nurminen, William E. Holben

Biological Sciences Faculty Publications

A DNA-based, direct method for initial characterization of the total bacterial community in ileum and cecum of the chicken gastrointestinal (GI) tract was developed. The efficiencies of bacterial extraction and lysis were >95 and >99%, respectively, and therefore the DNA recovered should accurately reflect the bacterial communities of the ileal and cecal digesta. Total bacterial DNA samples were fractionated according to their percent G+C content. The profiles reflecting the composition of the bacterial community were reproducible within each compartment, but different between the compartments of the GI tract. This approach is independent of the culturability of the bacteria in the …

Asymmetrical Force Production In The Maneuvering Flight Of Pigeons, Douglas R. Warrick, Kenneth P. Dial, Andrew A. Biewener

Biological Sciences Faculty Publications

Downstroke force produced by Rock Doves (Columba livia) as they negotiated an obstacle course was measured using in vivo recordings of delto-pectoral crest strain. During this slow $(<6\ {\rm m}\ {\rm s}^{-1})$ , maneuvering flight, pigeons produced a series of four to six successive wingbeats in which the wing on the outside of the turn produced greater peak force than the wing on the inside of the turn, suggesting that the birds maneuvered in a saltatory manner during slow flight. This asymmetrical downstroke force may be used to increase or reestablish bank lost during upstroke, or it may be directed as thrust to compensate for adverse yaw or create excess yaw to alter the bird's direction of flight. Continuous production of asymmetrical downstroke force through a turn differs from the traditional model of maneuvering flight, in which asymmetrical force is used only to initiate a bank, the forces are briefly reversed to arrest the momentum of the roll and then equalized to maintain the established bank, and the redirected lift of the wings then effects a turn. Although this traditional model probably describes most turns initiated during fast and gliding flight in birds, it underestimates the complexity of maneuvering during slow, flapping flight, where sophisticated kinematics and neuromuscular control are needed to change direction effectively.

On The Importance Of Stopover Sites To Migrating Birds, Richard L. Hutto

Biological Sciences Faculty Publications

No abstract provided.

Increased Photosynthesis Offsets Costs Of Allocation To Sapwood In An Arid Environment, Eileen V. Carey, Ragan M. Callaway, Evan H. Delucia

Biological Sciences Faculty Publications

We assessed the effect that varying patterns of biomass allocation had on growth of ponderosa pine (Pinus ponderosa) growing in the desert climate of the Great Basin and the montane climate of the eastern Sierra Nevada. Prior work established that desert trees have lower leaf:sapwood area ratios than montane trees (0.104 and 0.201 m²/cm², respectively) and proportionally greater stem respiration. Sapwood:leaf mass ratios are also greater and increase more as a function stem diameter in desert than in montane trees. We hypothesized that this increased allocation of carbon to stem sapwood and stem respiration …

Bacterial Stress Responses To 1-Megahertz Pulsed Ultrasound In The Presence Of Microbubbles, Amy Cheng Vollmer, Sylvia D. Sakyiama Kwakye , '98, Matthew Evan Halpern , '98, E. Carr Everbach

Engineering Faculty Works

Members of a panel of stress-responsive biosensors have been used to study the effect of megahertz frequency ultrasound onEscherichia coli. Insonification causes acoustic cavitation, the collapse of oscillating microbubbles in solution, which can damage bacterial cells. A focused 1-MHz ultrasound transducer, capable of generating a spatial peak pulse average intensity of 500 W/cm2, was used to treat liquid bacterial cultures. Stress-responsive promoters fused to luxCDABE allowed the continuous measurement of light produced as a result of protein damage, DNA damage, oxidative stress, and membrane perturbation. A promoter responsive to ammonia limitation was not transcriptionally activated under test conditions. In contrast …

Position Effect Takes Precedence Over Target Sequence In Determination Of Adenine Methylation Patterns In The Nuclear Genome Of A Eukaryote, Tetrahymena Thermophila, Kathleen M. Karrer, Teresa A. Van Nuland

Biological Sciences Faculty Research and Publications

Approximately 0.8% of the adenine residues in the macronuclear DNA of the ciliated protozoan Tetrahymena thermophila are modified to N⁶-methyladenine. DNA methylation is site specific and the pattern of methylation is constant between clonal cell lines. In vivo, modification of adenine residues appears to occur exclusively in the sequence 5′-NAT-3′, but no consensus sequence for modified sites has been found. In this study, DNA fragments containing a site that is uniformly methylated on the 50 copies of the macronuclear chromosome were cloned into the extrachromosomal rDNA. In the novel location on the rDNA minichromosome, the site was …

Structural Basis Of Activity And Subunit Recognition In G Protein Heterotrimers, Mark A. Wall, Bruce A. Posner, Stephen R. Sprang

Biological Sciences Faculty Publications

Background: Inactive heterotrimeric G proteins are composed of a GDP-bound α subunit (G(α)) and a stable heterodimer of G(β) and G(γ) subunits. Upon stimulation by a receptor, G(α) subunits exchange GDP for GTP and dissociate from G(βγ) both G(α) and G(βγ) then interact with downstream effectors. Isoforms of G(α), G(β) and G(γ) potentially give rise to many heterotrimeric combinations, limited in part by amino acid sequence differences that lead to selective interactions. The mechanism by which GTP promotes G(βγ) dissociation is incompletely understood. The Gly203→Ala mutant of G(iα1) binds and hydrolyzes GTP normally but does not dissociate from G(βγ) demonstrating …

Transport Of Axl2p Depends On Erv14p, An Er–Vesicle Protein Related To The Drosophila Cornichon Gene Product, Jacqueline Powers, Charles Barlowe

Dartmouth Scholarship

COPII-coated ER-derived transport vesicles from Saccharomyces cerevisiae contain a distinct set of membrane-bound polypeptides. One of these polypeptides, termed Erv14p (ER-vesicle protein of 14 kD), corresponds to an open reading frame on yeast chromosome VII that is predicted to encode an integral membrane protein and shares sequence identity with the Drosophila cornichon gene product. Experiments with an epitope-tagged version of Erv14p indicate that this protein localizes to the ER and is selectively packaged into COPII-coated vesicles. Haploid cells that lack Erv14p are viable but display a modest defect in bud site selection because a transmembrane secretory protein, Axl2p, is not …

Rapid Detection Of Listeria Monocytogenes In Dairy Samples Utilizing A Pcr-Based Fluorogenic 5′ Nuclease Assay, T. Cox, C. Frazier, J. Tuttle, S. Flood, L. Yagi, C. T. Yamashiro, R. Behari, C. Paszko, R. J. Cano

Biological Sciences

The presence of Listeria monocytogenes as a dairy food contaminant is a lethal threat to dairy industrialists; therefore, products tainted with L. monocytogenes must be quickly detected and removed from production. This fluorogenic PCR-based assay was developed to rapidly detect L. monocytogenes contamination in dairy samples before a final product is distributed. The detection method employed uses a PCR primer pair and a fluorogenic TaqMan probe which bind to a region of a virulence determinant gene specific to L. monocytogenes. As the DNA target is amplified, the 5′ nuclease activity of Taq DNA polymerase hydrolyzes the internal fluorogenic probe …

Is Population Genetics Mired In The Past?, Andrew J. Bohonak, Neil Davies, George K. Roderick, Francis X. Villablanca

Biological Sciences

No abstract provided.

Continued Utilization Of Ccr5 Coreceptor By A Newly Derived T-Cell Line-Adapted Isolate Of Human Immunodeficiency Virus Type 1, Kathryn E. Follis, Meg Trahey, Rachel A. Lacasse, Jack H. Nunberg

Biological Sciences Faculty Publications

The differential use of CC chemokine receptor 5 (CCR5) and CXC chemokine receptor 4 (CXCR4) may be intimately involved in the transmission and progression of human immunodeficiency virus infection. Changes in coreceptor utilization have also been noted upon adaptation of primary isolates (PI) to growth in established T-cell lines. All of the T-cell line-adapted (TCLA) viruses studied to date utilize CXCR4 but not CCR5. This observation had been suggested as an explanation for the sensitivity of TCLA, but not PI, viruses to neutralization by recombinant gp120 antisera and V3-directed monoclonal antibodies, but recent studies have shown coreceptor utilization to be …

Bowen Ratio Estimates Of Evapotranspiration For Tamarix Ramosissima Stands On The Virgin River In Southern Nevada, D. A. Devitt, Anna Sala, S. D. Smith, J. Cleverly, L. K. Shaulis, R. Hammett

Biological Sciences Faculty Publications

A Bowen ratio energy balance was conducted over a Tamarix ramosissima (saltcedar) stand growing in a riparian corridor along the Virgin River in southern Nevada, Measurements in two separate years were compared and contrasted on the basis of changes in growing conditions. In 1994, a drought year, record high temperatures, dry winds, and a falling water table caused partial wilt of outer smaller twigs in the canopy of many trees in the stand around the Bowen tower. Subsequently, evapotranspiration (ET) estimates declined dramatically over a 60-day period (11 mm d(-1) to <1 mm d(-1)). In 1995, the Virgin River at the Bowen tower area changed its course, hydrologically isolating the Tamarix stand in the vicinity of the tower. In 1996, a 25% canopy loss was visually estimated for the Tamarix growing in the area of the tower. Higher soil temperatures relative to air temperatures were recorded in 1996 in response to this loss in canopy, With a more open canopy, thermally induced turbulence was observed in 1996, On day 160 of 1996, a 28 degrees C rise over a 9-hour period was correlated with increased wind speeds of greater than 4 m s(-1). Subsequently, higher ET estimates were made in 1996 compared to 1994 (145 cm versus 75 cm), However, the energy balance was dominated by advection in 1996, with latent energy flux exceeding net radiation 65% of the measurement days compared to only 11% in 1994, We believe this advection was on a scale of the floodplain (hundreds of meters) as opposed to regional advection, since the majority of wind (90%) was in a N-S direction along the course of the river, and that a more open canopy allowed the horizontal transfer of energy into the Tamarix stand at the Bowen tower. Our results suggest that Tamarix has the potential to be both a low water user and a high water user, depending on moisture availability, canopy development, and atmospheric demand, and that advection can dominate energy balances and ET in aridland riparian zones such as the Virgin River.

Conceptual Breakthroughs In Developmental Biology, Scott F. Gilbert

Biology Faculty Works

No abstract provided.

Immunological Relationship Between The Class I Epitope Of Streptococcal M Protein And Myosin, Anthony Quinn, Kent Ward, Vincent A. Fischetti, Mark E. Hemric, Medeleine W. Cunningham

Faculty Publications and Presentations

The class I epitope of streptococcal M protein is an epidemiological marker for acute rheumatic fever (ARF)-associated serotypes of group A streptococci and is recognized by anti-M protein monoclonal antibody (MAb) 10B6. Using MAb 10B6, we determined the relationship between the class I epitope of M protein and the a-helical coiled-coil protein myosin. MAb 10B6 reacted by enzyme-linked immunosorbent assay and Western blotting with human cardiac myosin and rabbit skeletal myosin and its heavy meromyosin (HMM) subfragment. Overlapping synthetic peptides of M5 protein were used to identify the region of M5 protein recognized by MAb 10B6. Two C repeat peptides …

Feather Evidence Helps Clarify Locality Of Anthropological Artifacts In The Museum Of Mankind, Carla J. Dove

Pacific Studies

Species of birds used on ethnographic artifacts collected during the eighteenth century and stored at the Museum of Mankind (British Museum) were identified by using microscopic and whole-feather characters. One of the objects (VAN 345), labeled as having been collected on Vancouver’s voyage to Tahiti, was a feather pendant made of long strands of chicken feathers with small red feathers at the base. The small red feathers were examined microscopically, compared with museum study skins of all possible species, and identified as Vestiaria coccinea (‘I‘iwi). Since this species is known only from the Hawaiian Archipelago, it was determined that the …

Developmental Regulation Of A Cyclin-Dependent Kinase Inhibitor Controls Postembryonic Cell Cycle Progression In Caenorhabditis Elegans, Yang Hong, Richard Roy, Victor Ambros

Dartmouth Scholarship

C. elegans cki-1 encodes a member of the CIP/KIP family of cyclin-dependent kinase inhibitors, and functions to link postembryonic developmental programs to cell cycle progression. The expression pattern of cki-1::GFP suggests that cki-1 is developmentally regulated in blast cells coincident with G1, and in differentiating cells. Ectopic expression of CKI-1 can prematurely arrest cells in G1, while reducing cki-1 activity by RNA-mediated interference (RNAi) causes extra larval cell divisions, suggesting a role for cki-1 in the developmental control of

INTRODUCTION

The proper development of a multicellular organism requires the precise orchestration of cell proliferation and differentiation. Despite considerable progress toward …

The A326s Mutant Of G(Iα1) As An Approximation Of The Receptor-Bound State, Bruce A. Posner, Mark B. Mixon, Mark A. Wall, Stephen R. Sprang, Alfred G. Gilman

Biological Sciences Faculty Publications

Agonist-bound heptahelical receptors activate heterotrimeric G proteins by catalyzing exchange of GDP for GTP on their α subunits. In search of an approximation of the receptor-α subunit complex, we have considered the properties of A326S G(iα1), a mutation discovered originally in G(sα) (Iiri, T., Herzmark, P., Nakamoto, J. M., Van Dop, C., and Bourne, H. R. (1994) Nature 371, 164-168) that mimics the effect of receptor on nucleotide exchange. The mutation accelerates dissociation of GDP from the α(i1)β₁γ₂ heterotrimer by 250-fold. Nevertheless, affinity of mutant G(iα1) for GTPγS is high in the presence of Mg²⁺, …

Identification Of A Functional Homolog Of The Yeast Copper Homeostasis Gene Atx1 From Arabidopsis, Edward Himelblau, Helena Mria, Su-Ju Lin, Valeria Cizewski Culotta, Lola Penarrubia, Richard M. Amasino

Biological Sciences

A cDNA clone encoding a homolog of the yeast (Saccharomyces cerevisiae) gene Anti-oxidant 1 (ATX1) has been identified from Arabidopsis. This gene, referred to as Copper CHaperone (CCH), encodes a protein that is 36% identical to the amino acid sequence of ATX1 and has a 48-amino acid extension at the C-terminal end, which is absent from ATX1 homologs identified in animals. ATX1-deficient yeast (atx1) displayed a loss of high-affinity iron uptake. Expression of CCH in the atx1 strain restored high-affinity iron uptake, demonstrating that CCH is a functional homolog of ATX1 …

Study Of The Baie Gene In Bile Acid 7Α-Dehydroxylating Bacteria, Yasemin Kaya

Masters Theses & Specialist Projects

Intestinal bile acid 7α-dehydroxylating bacteria have recently been implicated in cholesterol allstone disease. Eubacterium sp. V.P.I. 12708, a bile acid 7α-dehydroxylating bacterium, contains multiple bile acid inducible (bai) genes which encode the enzymes responsible for bile acid 7a-dehydroxylation. The baiE gene encodes a bile acid dehydratase activity in Eubacterium sp.V.P.I. 12708. Using the polymerase chain reaction assay we determined the presence or absence of baiE-like genes in five clostridial bile-acid 7α-dehydroxylating strains: Clostridium sp. TO-931, Clostridium sp. HD-17, Clostridium sp. TN-271, Clostridium bifermentans 1-55, and Clostridium sordellii ATCC 9714. Results from all the strains tested showed amplification at the predicted …

Multiple Duplications Of Yeast Hexose Transport Genes In Response To Selection In A Glucose-Limited Environment, Celeste J. Brown, Kristy M. Todd, R. Frank Rosenzweig

Biological Sciences Faculty Publications

When microbes evolve in a nutrient-limited environment, natural selection can be predicted to favor genetic changes that give cells greater access to limiting substrate. We analyzed a population of baker's yeast that underwent 450 generations of glucose-limited growth. Relative to the strain used as the inoculum, the predominant cell type at the end of this experiment sustains growth at significantly lower steady-state glucose concentrations and demonstrates markedly enhanced cell yield per mole glucose, significantly enhanced high-affinity glucose transport, and greater relative fitness in pairwise competition. These changes are correlated with increased levels of mRNA hybridizing to probe generated from the …

The Effect Of Exercise Training On Cardiovascular Dynamics In The Diabetic Rat, Nicole Marie Griffith

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Nicole Marie Griffith on July 24, 1998.

Translation Of Random Transcripts Generated By Tdt: Potential Use In Polysome Peptide Libraries, Michael Lane Spencer

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Michael Lane Spencer on July 22, 1998.

Concerted Formation Of Macromolecular Suppressor-Mutator Transposition Complexes, Ramesh Raina, Michael Schläppi, Balasulojini Karunanandaa, Adam Elhofy, Nina V. Fedoroff

Biological Sciences Faculty Research and Publications

Transposition of the maize Suppressor-mutator (Spm) transposon requires two element-encoded proteins, TnpA and TnpD. Although there are multiple TnpA binding sites near each element end, binding of TnpA to DNA is not cooperative, and the binding affinity is not markedly affected by the number of binding sites per DNA fragment. However, intermolecular complexes form cooperatively between DNA fragments with three or more TnpA binding sites. TnpD, itself not a sequence-specific DNA-binding protein, binds to TnpA and stabilizes the TnpA-DNA complex. The high redundancy of TnpA binding sites at both element ends and the protein-protein interactions between DNA-bound TnpA …

Thermoregulation Of Escherichia Coil Pap Transcription: H-Ns Is A Temperature-Dependent Dna Methylation Blocking Factor, Christine A. White-Ziegler, Melinda L. Angus Hill, Bruce A. Braaten, Marjan W. Van Der Woude, David A. Low

Biological Sciences: Faculty Publications

The expression of Pap pili that facilitate the attach- ment of Escherichia coli to uroepithelial cells is shut off outside the host at temperatures below 268C. Ribo- nuclease protection analysis showed that this thermo- regulatory response was rapid as evidenced by the absence of papBA transcripts, coding for Pap pilin, after only one generation of growth at 238C. The his- tone-like nucleoid structuring protein H-NS and DNA sequences within papB were required for thermoregu- lation, but the PapB and PapI regulatory proteins were not. In vivo analysis of pap DNA methylation patterns indicated that H-NS or a factor regulated by …

Molecular Analysis Of Bacterial Communities In A Three-Compartment Granular Activated Sludge System Indicates Community-Level Control By Incompatible Nitrification Processes, William Holben, Kazuhiko Noto, Tatsuo Sumino, Yuichi Suwa

Biological Sciences Faculty Publications

Bacterial community structure and the predominant nitrifying activities and populations in each compartment of a three-compartment activated sludge system were determined, Each compartment was originally inoculated with the same activated sludge community entrapped in polyethylene glycol gel granules, and ammonium nitrogen was supplied to the system in an inorganic salts solution at a rate of 5.0 g of N liter of granular activated sludge(-1) day(-1). After 150 days of operation, the system was found to comprise a series of sequential nitrifying reactions (K, Note, T. Ogasawara, Y, Suwa, and T. Sumino, Water Res. 32:769-773, 1998), presumably mediated by different bacterial …

Rad52 Associates With Rpa And Functions With Rad55 And Rad57 To Assemble Meiotic Recombination Complexes, Stephen L. Gasior

Biological Sciences Faculty Publications

We show that the Saccharomyces cerevisiae recombination protein Rad52 and the single-strand DNA-binding protein RPA assemble into cytologically detectable subnuclear complexes (foci) during meiotic recombination. Immunostaining shows extensive colocalization of Rad52 and RPA and more limited colocalization of Rad52 with the strand exchange protein Rad51. Rad52 and RPA foci are distinct from those formed by Rad51, and its meiosis-specific relative Dmc1, in that they are also detected in meiosis during replication. In addition, RPA foci are observed during mitotic S phase. Double-strand breaks (DSBs) promote formation of RPA, Rad52, and Rad51 foci. Mutants that lack Spo11, a protein required for …

Efficacy Of AllowashTm Solution In Solubilization Of Bone Marrow, Alyce Marie Linthurst

Biological Sciences Theses & Dissertations

LifeNet currently cleans allograft bone utilizing Allowash^TM Technology, which encompasses the use of a closed continuous circulation chamber to remove bone marrow by flushing it with Allowash^TM Solution for a prescribed time and temperature after which, it is rinsed with various solutions to remove residual detergent that could be toxic to the recipient. A portion of this process employs Allowash^TM Solution to improve the solubilization and removal of protein and cellular elements in the red bone marrow. This study examines the effectiveness of Allowash^TM Solution in comparison to its component detergents Nonidet P40, Nonoxynol 9 and …

A Role For Nima In The Nuclear Localization Of Cyclin B In Aspergillus Nidulans, L. Wu, S. A. Osmani, Peter M. Mirabito

Biology Faculty Publications

NIMA promotes entry into mitosis in late G2 by some mechanism that is after activation of the Aspergillus nidulans G2 cyclin-dependent kinase, NIMX^CDC2/NIME^{Cyclin B}. Here we present two independent lines of evidence which indicate that this mechanism involves control of NIMX^CDC2/NIME^{Cyclin B} localization. First, we found that NIME^{Cyclin B} localized to the nucleus and the nucleus-associated organelle, the spindle pole body, in a NIMA-dependent manner. Analysis of cells from asynchronous cultures, synchronous cultures, and cultures arrested in S or G2 showed that NIME^{Cyclin B} was predominantly nuclear during interphase, with maximal …

Exchange Of Substrate And Inhibitor Specificities Between Adenylyl And Guanylyl Cyclases, R. K. Sunahara, A. Beuve, J. J.G. Tesmer, S. R. Sprang, D. L. Garbers, A. G. Gilman

Biological Sciences Faculty Publications

The active sites of guanylyl and adenylyl cyclases are closely related. The crystal structure of adenylyl cyclase and modeling studies suggest that specificity for ATP or GTP is dictated in part by a few amino acid residues, invariant in each family, that interact with the purine ring of the substrate. By exchanging these residues between guanylyl cyclase and adenylyl cyclase, we can completely change the nucleotide specificity of guanylyl cyclase and convert adenylyl cyclase into a nonselective purine nucleotide cyclase. The activities of these mutant enzymes remain fully responsive to their respective stimulators, sodium nitroprusside and G(s)α. The specificity of …