Life Sciences Commons^™

Characteristic Genome Rearrangements In Experimental Evolution Of Saccharomyces Cerevisiae, Maitreya J. Dunham, Hassan Badrane, Tracy Ferea, Julian Adams, Patrick O. Brown, Frank Rosenzweig, David Botstein

Biological Sciences Faculty Publications

Genome rearrangements, especially amplifications and deletions, have regularly been observed as responses to sustained application of the same strong selective pressure in microbial populations growing in continuous culture. We studied eight strains of budding yeast (Saccharomyces cerevisiae) isolated after 100-500 generations of growth in glucose-limited chemostats. Changes in DNA copy number were assessed at single-gene resolution by using DNA microarray-based comparative genomic hybridization. Six of these evolved strains were aneuploid as the result of gross chromosomal rearrangements. Most of the aneuploid regions were the result of translocations, including three instances of a shared breakpoint on chromosome 14 immediately adjacent to …

Convergent Demographic Effects Of Insect Attack On Related Thistles In Coastal Vs. Continental Dunes, John L. Maron, Julie K. Combs, Svata M. Louda

Biological Sciences Faculty Publications

Insect herbivory is common, but the conditions under which it reduces the fitness and population size of plants remain poorly understood. We quantified population-level impacts of floral herbivory by specialized insects on cobweb thistle (Cirsium occidentale var. occidentale) in a California coastal dune ecosystem, and then compared these demographic effects to those published for Platte thistle (Cirsium canescens) in similarly designed exclusion experiments in the continental sand dune ecosystem in the Great Plains. As a separate test of the strength of the seed-to-seedling linkage, we quantified seedling establishment rates in seed addition plots and compared these …

Plasticity And Genetic Diversity May Allow Saltcedar To Invade Cold Climates In North America, Jason P. Sexton, J. K. Mckay, Anna Sala

Biological Sciences Faculty Publications

Two major mechanisms have been proposed to explain the ability of introduced populations to colonize over large habitat gradients, despite significant population bottlenecks during introduction: (1) Broad environmental tolerance-successful invaders possess life history traits that confer superior colonizing ability and/or phenotypic plasticity, allowing acclimation to a wide range of habitats. (2) Local adaptation-successful invaders rapidly adapt to local selective pressures. However, even with bottlenecks, many introduced species exhibit surprisingly high levels of genetic variation and thus the potential for evolutionary increases in invasive traits and plasticity. Here we assess the invasive potential of Tamarix ramosissima, by examining the degree of …

Calcium Binding To Calmodulin Mutants Monitored By Domain-Specific Intrinsic Phenylalanine And Tyrosine Fluorescence, W. S. Vanscyoc, B. R. Sorensen, E. Rusinova, William Laws, J. B. A. Ross, M. A. Shea

Chemistry and Biochemistry Faculty Publications

Cooperative calcium binding to the two homologous domains of calmodulin (CaM) induces conformational changes that regulate its association with and activation of numerous cellular target proteins. Calcium binding to the pair of high-affinity sites (III and IV in the C-domain) can be monitored by observing calcium-dependent changes in intrinsic tyrosine fluorescence intensity (lambda(ex)/lambda(em) of 277/320 nm). However, calcium binding to the low-affinity sites (I and II in the N-domain) is more difficult to measure with optical spectroscopy because that domain of CaM does not contain tryptophan or tyrosine. We recently demonstrated that calcium-dependent changes in intrinsic phenylalanine fluorescence (lambdaex/lambdaem of …

Groel Expression In Gyrb Mutants Of Borrelia Burgdorferi, Janet Alverson, D. Scott Samuels

Biological Sciences Faculty Publications

GroEL protein and groEL mRNA transcript were up-regulated in gyrB mutants of Borrelia burgdorferi, a causative agent of Lyme disease. Furthermore, the protein and transcript levels in gyrB mutants were greater than those in experimentally heat-shocked cultures of wild-type B. burgdorferi. Circular DNA in the gyrB mutants was more relaxed than in wild-type cells, although groEL is on the linear chromosome of B. burgdorferi. To our knowledge, this is the first evidence, albeit indirect, for the effect of DNA topology on gene expression from a linear DNA molecule in a bacterium.

Incentives Toward Conservation Of Argaii Ovis Ammon: A Case Study Of Trophy Hunting In Western China, R. B. Harris, Dan H. Pletscher

Wildlife Biology Faculty Publications

We investigated management of wildlife, habitat and the hunting programme in Aksai County, Gansu Province, People's Republic of China, during 1997-2000. Argali Ovis amnion is the focal species both for conservation and hunting. The hunting programme is intended to produce incentives to conserve wildlife and habitat. Poaching, a serious concern throughout western China, has been reduced in recent years in Aksai. Wildlife population trends are unknown because standardized surveys were begun only in 2000. Threats to argali in Aksai include livestock grazing, placer gold mining, and development of a dam, reservoir and aqueduct. The number of hunters participating in the …

Guanine And 7,8-Dihydro-8-Oxo-Guanine-Specific Oxidation In Dna By Chromium(V), Kent D. Sugden, Brooke Martin

Chemistry and Biochemistry Faculty Publications

The hexavalent oxidation state of chromium [Cr(VI)] is a well-established human carcinogen, although the mechanism of cancer induction is currently unknown. Intracellular reduction of Cr(VI) forms Cr(V), which is thought to play a fundamental role in the mechanism of DNA damage by this carcinogen. Two separate pathways of DNA damage, an oxidative pathway and a metal-binding pathway, have been proposed to account for the lesions observed in cell systems. We have used a model Cr(V) complex, N,N´-ethylenebis(salicylidene-animato)oxochromium(V) [Cr(V)-Salen], to investigate the oxidative pathway of DNA damage and to elucidate the lesions generated from this oxidation process. Reaction of Cr(V)-Salen with …

Culture-Independent Microbial Community Analysis Reveals That Inulin In The Diet Primarily Affects Previously Unknown Bacteria In The Mouse Cecum, Juha H. A. Apajalahti, Hannele Kettunen, Anu Kettunen, William E. Holben, Päivi H. Nurminen, Nina Rautonen, Marja Mutanen

Biological Sciences Faculty Publications

Inulin is a well-known fructose-based prebiotic which has been shown to stimulate the growth of bifidobacteria, a bacterial group generally considered beneficial for intestinal health. In the present study, we analyzed inulin-associated shifts in the total bacterial community of wild-type mice and mice carrying a genetically inactivated adenomatous polyposis coli tumor suppressor gene by using DNA-based approaches independent of bacterial culturability. Mice were fed a high-fat, nonfiber diet with or without inulin inclusion at a 10% (wt/wt) concentration. Cecal contents were analyzed after 0, 3, and 9 weeks on the experimental diets. Inulin inclusion significantly affected the total bacterial community …

Monte Carlo Simulation On The Indirect Exchange Interactions Of Co-Doped Zno Film, Abraham F. Jalbout, Hanning Chen, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

Monte Carlo simulations using a three-dimensional lattice model studied the Ruderman–Kittel–Kasuya–Yosida (RKKY) indirect exchange interaction of doped magnetic Co ions in ZnOfilms. The results of the calculations show that the RKKY interaction in Co-doped ZnO is long ranged and its magnitude is proportional to (inverse of the distance from a central ion). The sign oscillates with a frequency that depends on the concentration of the carrier. The long-distance sum of the RKKY indirect exchange energies is positive indicating that these materials are ferromagnetic, in direct correlation with previously reported results.

Distinct Interactions Of Gtp, Utp, And Ctp With G(S) Proteins, Andreas Gille, Hui-Yu Liu, Stephen R. Sprang, Roland Seifert

Biological Sciences Faculty Publications

Early studies showed that in addition to GTP, the pyrimidine nucleotides UTP and CTP support activation of the adenylyl cyclase (AC)-stimulating G(s) protein. The aim of this study was to elucidate the mechanism by which UTP and CTP support G(s) activation. As models, we used S49 wild-type lymphoma cells, representing a physiologically relevant system in which the beta(2)-adrenoreceptor (beta(2)AR) couples to G(s), and Sf9 insect cell membranes expressing beta(2)AR-Galpha(s) fusion proteins. Fusion proteins provide a higher sensitivity for the analysis of beta(2)AR-G(s) coupling than native systems. Nucleoside 5'-triphosphates (NTPs) supported agonist-stimulated AC activity in the two systems and basal AC …

Review Of: Riverine Flood Plains: Present State And Future Trends, Klement Tockner, Jack Arthur Stanford

Biological Sciences Faculty Publications

Natural flood plains are among the most biologically productive and diverse ecosystems on earth. Globally, riverine flood plains cover > 2 x 10(6) km(2), however, they are among the most threatened ecosystems. Floodplain degradation is closely linked to the rapid decline in freshwater biodiversity; the main reasons for the latter being habitat alteration, flow and flood control, species invasion and pollution. In Europe and North America, up to 90% of flood plains are already 'cultivated' and therefore functionally extinct. In the developing world, the remaining natural flood plains are disappearing at an accelerating rate, primarily as a result of changing hydrology. …

Cosolvent-Induced Transformation Of A Death Domain Tertiary Structure, Tsan Xiao, Kevin H. Gardner, Stephen R. Sprang

Biological Sciences Faculty Publications

The death domain (DD) of the protein kinase Pelle adopts a six-helix bundle fold in the crystal structure of the complex with its dimerization partner, Tube-DD. However, in crystals obtained from a solution of 45% 2-methyl-2,4-pentanediol (MPD), the C-terminal half of Pelle-DD folds into a single helix, and the N-terminal half of the molecule is disordered. The helical segment forms an antiparallel dimer with the corresponding helix of a symmetry-related molecule, and together they form extensive lattice interactions similar in number, composition, and buried surface to those in the six-helix bundle of the native fold. Secondary structure analysis by heteronuclear …

Genetic Evidence That Interhelical Packing Interactions In The Gp41 Core Are Critical For Transition Of The Human Immunodeficiency Virus Type 1 Envelope Glycoprotein To The Fusion-Active State, Kathryn E. Follis, Scott J. Larson, Min Lu, Jack H. Nunberg

Biological Sciences Faculty Publications

The envelope glycoprotein complex (gp120-gp41) of human immunodeficiency virus type 1 (HIV-1) promotes the fusion of viral and cellular membranes through formation of the fusion-active six-helix bundle in the gp41 ectodomain. This gp41 core structure consists of three C-terminal helices packed in an antiparallel manner into hydrophobic grooves on the surface of the N-terminal trimeric coiled coil. Alanine mutations that destabilize the N- and C-terminal interhelical packing interactions also reduce viral infectivity. Here we show that viruses bearing these mutations exhibit a marked potentiation of inhibition by peptides that make up the gp41 core. By contrast, these viruses are unchanged …

The Neisseria Lipooligosaccharide-Specific Alpha-2,3-Sialyltransferase Is A Surface-Exposed Outer Membrane Protein, Dawn M. Shell, Lisa Chiles, Ralph C. Judd, Samar Seal, Richard F. Rest

Biological Sciences Faculty Publications

Neisseria gonorrhoeae and Neisseria meningitidis express an similar to43-kDa alpha-2,3-sialyltransferase (Lst) that sialylates the surface lipooligosaccharide (LOS) by using exogenous (in all N. gonorrhoeae strains and some N. meningitidis serogroups) or endogenous (in other N. meningitidis serogroups) sources of 5'-cytidinemonophospho-N-acetylneuraminic acid (CMP-NANA). Sialylation of LOS can protect N. gonorrhoeae and N. meningitidis from complement-mediated serum killing and from phagocytic killing by neutrophils. The precise subcellular location of Lst has not been determined. We confirm and extend previous studies by demonstrating that Lst is located in the outer membrane and is surface exposed in both N. gonorrhoeae and N. meningitidis. Western …

Magnetization Reversal Of Elliptical Co/Cu/Co Pseudo-Spin Valve Dots, Ngocnga Dao, Scott L. Whittenburg, Y. Hao, Leszek M. Malkinski, Jian Qing Wang, C. A. Ross

Chemistry and Biochemistry Faculty Publications

We present our recent simulated results on Cr (5 nm)/ Cu (5 nm)/ Co (5 nm)/ Cu (3 nm)/ Co (2 nm) pseudo-spin valve dots. The simulated results agree qualitatively with the experimental results. Three different sizes of elliptical dots, and were simulated. Our simulations show that in these types of dots magnetization reversal occurs by the formation of domain walls: for and for No domain wall was observed in the reversal of the dots. For such dots, the simulated loops show a small two-step reversal pattern with the thin upper layer partially reversing followed by complete reversal of both …

Threshold Evolution In Exotic Populations Of A Polyphenic Beetle, Armin P. Moczek, John Hunt, Douglas J. Emlen, Leigh W. Simmons

Biological Sciences Faculty Publications

Polyphenic development is thought to play an important role in the evolution of phenotypic diversity and morphological novelties, yet the evolution of polyphenisms has rarely been documented in natural populations. Here we compare the morphologies of male dung beetles (Onthophagus taurus; Coleoptera: Scarabaeidae) from populations introduced to Australia and the eastern United States. Males in this species express two alternative morphologies in response to larval feeding conditions. Males encountering favourable conditions grow larger than a threshold body size and develop a pair of horns on their heads, whereas males that encounter poor conditions do not reach this threshold size and …

The Fitness Consequences Of Interspecific Eavesdropping Between Plants, Richard Karban, John L. Maron

Biological Sciences Faculty Publications

Although many ecologists have discounted the possibility of communication between plants, recent work demonstrates that wild tobacco plants with experimentally clipped sagebrush neighbors suffer less leaf herbivory than tobacco controls with unclipped neighbors. In this report, we examine the fitness consequences of resistance induced by eavesdropping. Annual tobacco plants with clipped sagebrush neighbors produced more flowers and seed-bearing capsules than plants with unclipped neighbors although these performance measures varied considerably over the five years of the study. Tobacco plants with clipped neighbors also suffered more frost damage than controls in one year. There was no indication that eavesdropping was more …

The Southern African Regional Science Initiative (Safari 2000): Overview Of The Dry Season Field Campaign, R. J. Swap, H. J. Annegarn, J. T. Suttles, J. Haywood, M. C. Helmlinger, C. Hely, Peter V. Hobbs, B. N. Holben, J. Ji, M. D. King, T. Landmann, W. Maenhaut, L. Otter, B. Pak, S. J. Piketh, S. Platnick, J. Privette, D. Roy, A. M. Thompson, Darold E. Ward, Robert J. Yokelson

Chemistry and Biochemistry Faculty Publications

The Southern African Regional Science Initiative (SAFARI 2000) is an international science project investigating the earth-atmosphere-human system in southern Africa. The programme was conducted over a two-year period from March 1999 to March 2001. The dry season field campaign (August-September 2000) was the most intensive activity and involved over 200 scientists from eighteen countries. The main objectives were to characterize and quantify biogenic, pyrogenic and anthropogenic aerosol and trace gas emissions and their transport and transformations in the atmosphere, and to validate NASA's Earth Observing System's satellite Terra within a scientific context. Five aircraft - two South African Weather Service …

Snail Kite Nest Success And Water Levels : A Reply To Beissinger And Snyder, Victoria J. Dreitz, Robert E. Bennetts, Brian Toland, Wiley M. Kitchens, Michael W. Collopy

Wildlife Biology Faculty Publications

Beissinger and Snyder present a commentary on our recent paper on spatial and temporal variability in nest success of Snail Kites (Rostrhamus sociabilis) in Florida (Dreitz et al. 2001). Beissinger and Snyder reanalyze a subset of data presented in our original paper to show that water levels have a significant influence on nest success. To make their argument, the authors conduct separate analyses for 5 of the original 11 wetlands; including only those having the most data. We agree with Beissinger and Snyder that water levels can affect nest success in some areas or years, as we stated …

Cost Of Defense In The Context Of Plant Competition: Brassica Rapa May Grow And Defend, David H. Siemens, Shannon H. Garner, Thomas Mitchell-Olds, Ragan M. Callaway

Biological Sciences Faculty Publications

Theory on costs of plant defense against herbivory in stressful environments predicts that costs should increase when competition is intense. This amplifies a fundamental dilemma that plants are thought to face: allocate limited resources to grow fast enough to compete, or invest these resources in secondary metabolites to maintain defense. We studied costs associated with genetic and environmental variation in secondary metabolite production of Brassica rapa in the presence and absence of the generalist competitor Lolium perenne. We used experimental quantitative genetics (artificial selection) to manipulate genetic variation, and herbivore-induction treatments to produce environmental variation in myrosinase and glucosinolate …

Unexpected Changes In Soil Phosphorus Dynamics Along Pasture Chronosequences In The Humid Tropics, Alan R. Townsend, Gregory P. Asner, Cory C. Cleveland, Margaret E. Lefer, Mercedes M. C. Bustamante

Ecosystem and Conservation Sciences Faculty Publications

Phosphorus (P) is widely believed to limit plant growth and organic matter storage in a large fraction of the world's lowland tropical rain forests. We investigated how the most common land use change in such forests, conversion to cattle pasture, affects soil P fractions along pasture chronosequences in the central Brazilian Amazon and in southwestern Costa Rica. Our sites represent a broad range in rainfall, soil type, management strategies, and total soil P (45.2–1228.0 μg P/g soil), yet we found some unexpected and at times quite similar changes in soil P in all sites. In the Brazilian sites, where rainfall …

Livelihood Security And Protected Area Management, Stephen F. Siebert, Jill M. Belsky

Ecosystem and Conservation Sciences Faculty Publications

No abstract provided.

Crystallization Of Complex Between Soluble Domains Of Adenylyl Cyclase And Activated Gs Alpha, John J. Tesmer, Roger K. Sunahara, David A. Fancy, Alfred G. Gilman, Stephen R. Sprang

Biological Sciences Faculty Publications

No abstract provided.

Exploring Visitor Experiences On Going-To-The-Sun Road In Glacier National Park, Robert N. Giordano

Graduate Student Theses, Dissertations, & Professional Papers

Going-to-the-Sun Road (GTSR) is one of the premier road facilities in the world. As the only cross-mountain route through Glacier National Park, the road brings nearly two million visitors a year into the heart of Montana wilderness. How to meet this demand for travel while protecting the nature of the visitor experience and the pristine setting for which the experience exists is a challenge of on-going complexity.

This research was designed to assist park managers in determining future changes to GTSR by describing and analyzing the experiences on the road today. Through 40 onsite interviews at Logan Pass (the pinnacle …