Biology Commons^™

Riverine Macrosystems Ecology: Sensitivity, Resistance, And Resilience Of Whole River Basins With Human Alterations, Kevin E. Mccluney, N Leroy Poff, Margaret A. Palmer, James H. Thorp, Geoffrey C. Poole, Bradley S. Williams, Michael R. Williams, Jill S. Baron

Biological Sciences Faculty Publications

Riverine macrosystems are described here as watershed-scale networks of connected and interacting riverine and upland habitat patches. Such systems are driven by variable responses of nutrients and organisms to a suite of global and regional factors (eg climate, human social systems) interacting with finer-scale variations in geology, topography, and human modifications. We hypothesize that spatial heterogeneity, connectivity, and asynchrony among these patches regulate ecological dynamics of whole networks, altering system sensitivity, resistance, and resilience. Long-distance connections between patches may be particularly important in riverine macrosystems, shaping fundamental system properties. Furthermore, the type, extent, intensity, and spatial configuration of human activities …

Developmental Link Between Sex And Nutrition; Doublesex Regulates Sex-Specific Mandible Growth Via Juvenile Hormone Signaling In Stag Beetles, Hiroki Gotoh, Hitoshi Miyakawa, Asano Ishikawa, Yuki Ishikawa, Yasuhiro Sugime, Douglas J. Emlen, Laura C. Lavine, Toru Miura

Biological Sciences Faculty Publications

Sexual dimorphisms in trait expression are widespread among animals and are especially pronounced in ornaments and weapons of sexual selection, which can attain exaggerated sizes. Expression of exaggerated traits is usually male-specific and nutrition sensitive. Consequently, the developmental mechanisms generating sexually dimorphic growth and nutritiondependent phenotypic plasticity are each likely to regulate the expression of extreme structures. Yet we know little about how either of these mechanisms work, much less how they might interact with each other. We investigated the developmental mechanisms of sex-specific mandible growth in the stag beetle Cyclommatus metallifer, focusing on doublesex gene function and its …

Seasonal Patterns Of Microhabitat Selection By A Sub-Tropical Whip Spider, Phrynus Longipes, In The Luquillo Experimental Forest, Puerto Rico, Caroline A. Curtis, Christopher P. Bloch

Biological Sciences Faculty Publications

Phrynus longipes (Pocock 1894) is a top predator among arboreal invertebrates in the Luquillo Mountains of Puerto Rico, but many aspects of its ecology remain poorly understood. We sampled four of the most abundant tree species in the Luquillo Mountains during the dry and wet seasons of 2008 to evaluate microhabitat preferences of this species. In the dry season, P. longipes occurred significantly less frequently on a palm, Prestoea acuminata var. montana (Arecaceae), than the other tree species. Carapace length and the diameter of the tree on which an individual was found were positively correlated, suggesting competition for substrates. Microhabitat …

Avoidance Of Canopy Gaps By A Common Land Snail, Christopher P. Bloch, Michael Stock

Biological Sciences Faculty Publications

Because canopy gaps are characterized by elevated temperature and decreased humidity relative to closed-canopy forest, terrestrial gastropods may be exposed to greater desiccation stress in gaps than in undisturbed forest. We placed individuals of Caracolus caracolla at the edges of canopy gaps in montane forest in Puerto Rico and observed their movements. Individuals preferentially moved out of gaps except in one gap on the first night of the study, and the proportion of individuals recaptured inside gaps decreased over time. Individuals moved, on average, farther into forest than into gaps. Juveniles and adults responded similarly. These results suggest that C. …

Effects Of Polychlorinated Biphenyl (Pcb) Exposure On Response Perseveration And Ultrasonic Vocalization Emission In Rat During Development, Dena Krishnan, Howard C. Cromwell, Lee Meserve

Biological Sciences Faculty Publications

The 3 major symptoms of autistic spectrum disorders include 1) social behavioral alterations, 2) problems in communication and 3) higher-order motoric deficits of perseveration and stereotyped movements. Previous work has shown that early developmental exposure to polychlorinated biphenyls (PCBs) alters rat pup social motivation and juvenile rat social recognition/investigation. The present work extends this previous research by examining how perinatal PCB exposure alters motoric functions and communication abilities at different stages of development. Action perseveration was examined using performance measures from a T-maze environment. Communication abilities were evaluated by monitoring ultrasound emission in rat pups during a brief isolation from …

Progress Towards A Molecular Phylogeny Of Tachinidae, Year Two, Isaac S. Winkler, John O. Stireman Iii, John K. Moulton, Pierfilippo Cerretti, Jeremy D. Blaschke

Biological Sciences Faculty Publications

We reported last year (Stireman et al. 2013) in The Tachinid Times on our collaborative project, funded by the U.S. National Science Foundation, to study the phylogeny of Tachinidae on a worldwide scale. Since that report, we have made some significant progress towards our goal of assembling a robust phylogenetic tree for Tachinidae. Notably, Cerretti et al. (in press) completed a phylogenetic study using 135 morphological characters from 180 tachinid genera. Results from this study largely reflect, with some interesting exceptions, what we are finding from preliminary analyses of our molecular data. Although sampling of taxa and genes for the …

Piwi Homologs Mediate Histone H4 Mrna Localization To Planarian Chromatoid Bodies, Labib Rouhana, Jennifer A. Weiss, Ryan S. King, Phillip A. Newmark

Biological Sciences Faculty Publications

The well-known regenerative abilities of planarian flatworms are attributed to a population of adult stem cells called neoblasts that proliferate and differentiate to produce all cell types. A characteristic feature of neoblasts is the presence of large cytoplasmic ribonucleoprotein granules named chromatoid bodies, the function of which has remained largely elusive. This study shows that histone mRNAs are a common component of chromatoid bodies. Our experiments also demonstrate that accumulation of histone mRNAs, which is typically restricted to the S phase of eukaryotic cells, is extended during the cell cycle of neoblasts. The planarian PIWI homologs SMEDWI-1 and SMEDWI-3 are …

Chasing Tachinids ‘Down Under’: Expeditions Of The Phylogeny Of World Tachinidae Project, Part Ii Eastern Australia, James E. O'Hara, Pierfilippo Cerretti, John O. Stireman Iii, Isaac S. Winkler

Biological Sciences Faculty Publications

Last year we documented in the pages of this newsletter an expedition to the Western Cape of South Africa in search of tachinids for the “Phylogeny of World Tachinidae” project (Cerretti et al. 2013). The project itself was discussed in a separate article (Stireman et al. 2013). In this issue of The Tachinid Times we discuss our expedition to eastern Australia in late 2013. This trip took place so recently that we have yet to fully identify our material and as a result cannot record here all of the taxa we collected. Instead, we will add the taxa to a …

Is There Light After Depth? Distribution Of Periphyton Chlorophyll And Productivity In Lake Littoral Zones, Yvonne Vadeboncoeur, Shawn P. Devlin, Peter B. Mcintyre, M. J. Vander Zanden

Biological Sciences Faculty Publications

Periphyton and phytoplankton contribute to the base of lake food webs, and both groups of microalgae are influenced by resources and physical forcing. Spatial variation in light availability interacts with the physical dynamics of the water column to create predictable depth gradients in resources and disturbance that may differentially affect periphyton vs phytoplankton. We characterized the depth distribution of chlorophyll and productivity of periphyton on sediments (epipelon) and phytoplankton in the euphotic zones of 13 oligomesotrophic lakes that span a large size gradient (0.017–32,600 km²). Epipelic chlorophyll usually increased with depth in the epilimnion. Light was the primary …

Why Is Living Fast Dangerous? Disentangling The Roles Of Resistance And Tolerance Of Disease, James P. Cronin, Megan A. Rúa, Charles E. Mitchell

Biological Sciences Faculty Publications

Primary axes of host developmental tempo (HDT; e.g., slow-quick return continuum) represent latent biological processes and are increasingly used to a priori identify hosts that contribute disproportionately more to pathogen transmission. The influence of HDT on host contributions to transmission depends on how HDT influences both resistance and tolerance of disease. Here, we use structural equation modeling to address known limitations of conventional measures of resistance and tolerance. We first provide a general resistance-tolerance metamodel from which system-specific models can be derived. We then develop a model specific to a group of vector-transmitted viruses that infect hundreds of grass species …

Wild Bees Preferentially Visit Rudbeckia Flower Heads With Exaggerated Ultraviolet Absorbing Floral Guides, Lisa Horth, Laura Campbell, Rebecca Bray

Biological Sciences Faculty Publications

Here, we report on the results of an experimental study that assessed the visitation frequency of wild bees to conspecific flowers with different sized floral guides. UV absorbent floral guides are ubiquitous in Angiosperms, yet surprisingly little is known about conspecific variation in these guides and very few studies have evaluated pollinator response to UV guide manipulation. This is true despite our rich understanding about learning and color preferences in bees. Historical dogma indicates that flower color serves as an important long-range visual signal allowing pollinators to detect the flowers, while floral guides function as close-range signals that direct pollinators …

Natural Transformation Of Thermotoga Sp. Strain Rq7, Dongmei Han, Hui Xu, Rutika Puranik, Zhaohui Xu

Biological Sciences Faculty Publications

Background

Thermotoga species are organisms of enormous interest from a biotechnological as well as evolutionary point of view. Genetic modifications of Thermotoga spp. are often desired in order to fully release their multifarious potentials. Effective transformation of recombinant DNA into these bacteria constitutes a critical step of such efforts. This study aims to establish natural competency in Thermotoga spp. and to provide a convenient method to transform these organisms.

Results

Foreign DNA was found to be relatively stable in the supernatant of a Thermotoga culture for up to 6 hours. Adding donor DNA to T. sp. strain RQ7 at its …

Multiplexing With Three-Primer Pcr For Rapid And Economical Microsatellite Validation, Salla Vartia, Patrick C. Collins, Thomas F. Cross, Richard D. Fitzgerald, David T. Gauthier, Philip Mcginnity, Luca Mirimin, Jens Carlsson

Biological Sciences Faculty Publications

The next generation sequencing revolution has enabled rapid discovery of genetic markers, however, development of fully functioning new markers still requires a long and costly process of marker validation. This study reports a rapid and economical approach for the validation and deployment of polymorphic microsatellite markers obtained from a 454 pyrosequencing library of Atlantic cod, Gadus morhua, Linnaeus 1758. Primers were designed from raw reads to amplify specific amplicon size ranges, allowing effective PCR multiplexing. Multiplexing was combined with a three-primer PCR approach using four universal tails to label amplicons with separate fluorochromes. A total of 192 primer pairs …

Quantitative Factors Proposed To Influence The Prevalence Of Canine Tick-Bourne Disease Agents In The United States, Roger W. Stich, Byron L. Blagburn, Dwight D. Bowman, Christopher Carpenter, M. Roberto Cortinas, Sidney A. Ewing, Desmond Foley, Holly Gaff, Graham J. Hickling, R. Ryan Lash

Biological Sciences Faculty Publications

The Companion Animal Parasite Council hosted a meeting to identify quantifiable factors that can influence the prevalence of tick-borne disease agents among dogs in North America. This report summarizes the approach used and the factors identified for further analysis with mathematical models of canine exposure to tick-borne pathogens.

Basin Isolation And Oceanographic Features Influencing Lineage Divergence In The Humbug Damselfish (Dascyllus Aruanus) In The Coral Triangle, J. M. Raynal, E. D. Crandall, P. H. Barber, G. N. Mahardika, M. C. Lagman, Kent E. Carpenter

Biological Sciences Faculty Publications

The Coral Triangle is a hotspot for marine species diversity as well as for intraspecific genetic diversity. Here, we used nuclear RAG2 and mitochondrial D-Loop genes to identify deep genetic divergence among Dascyllus aruanus (Linnaeus, 1758) populations across relatively short scales within the Coral Triangle. Mitochondrial clades different by >20 mutational steps were completely isolated from one another across the distance between Java and the Lesser Sunda Islands, and also showed frequency differences in the eastern and western Philippines. Evidence for population structure in the Sulu Sea and at the Lesser Sunda Islands was also identified. Our results suggest that …

Comparison Of Phenology And Pathogen Prevalence, Including Infection With The Ehrlichia Muris-Like (Eml) Agent, Of Ixodes Scapularis Removed From Soldiers In The Midwestern And Northeastern United States Over A 15 Year Period (1997-2012), Ellen Stromdahl, Sarah Hamer, Sarah Jenkins, Lynne Sloan, Phillip Williamson, Erik Foster, Robyn Nadolny, Chad Elkins, Mary Vince, Bobbi Pritt

Biological Sciences Faculty Publications

Background: Since 1997, human-biting ticks submitted to the Department of Defense Human Tick Test Kit Program (HTTKP) of the US Army Public Health Command have been tested for pathogens by PCR. We noted differences in the phenology and infection prevalence among Ixodes scapularis ticks submitted from military installations in different geographic regions. The aim of this study was to characterize these observed differences, comparing the phenology and pathogen infection rates of I. scapularis submitted from soldiers at two sites in the upper Midwest ( Camp Ripley, MN, and Ft. McCoy, WI) and one site in the northeastern US (Ft. Indiantown …

Water As A Trophic Currency In Dryland Food Webs, Daniel C. Allen, Kevin E. Mccluney, Stephen R. Elser, John L. Sabo

Biological Sciences Faculty Publications

Water is essential for life on Earth, yet little is known about how water acts as a trophic currency, a unit of value in determining species interactions in terrestrial food webs. We tested the relative importance of groundwater and surface water in riparian food webs by manipulating their availability in dryland floodplains. Primary consumers (crickets) increased in abundance in response to added surface water and groundwater (contained in moist leaves), and predators (spiders and lizards) increased in abundance in response to added surface water, in spite of the presence of a river, an abundant water source. Moreover, the relative magnitude …

Population Genetic Structure In A Social Landscape: Barley In A Traditional Ethiopian Agricultural System, Leah H. Samberg, Lila Fishman, Fred W. Allendorf

Biological Sciences Faculty Publications

Conservation strategies are increasingly driven by our understanding of the processes and patterns of gene flow across complex landscapes. The expansion of population genetic approaches into traditional agricultural systems requires understanding how social factors contribute to that landscape, and thus to gene flow. This study incorporates extensive farmer interviews and population genetic analysis of barley landraces (Hordeum vulgare) to build a holistic picture of farmer-mediated geneflow in an ancient, traditional agricultural system in the highlands of Ethiopia. We analyze barley samples at 14 microsatellite loci across sites at varying elevations and locations across a contiguous mountain range, and across farmer-identified …

Wolves Facilitate The Recovery Of Browse-Sensitive Understory Herbs In Wisconsin Forests, Krystle Bouchard, Jane E. Wiedenhoeft, Adrian P. Wydeven, Thomas P. Rooney

Biological Sciences Faculty Publications

We asked whether wolf re-colonization would facilitate increased growth and reproduction of three browse-sensitive plant species. We hypothesized plant size and the proportion of reproductive individuals would be lowest in areas with no wolves, intermediate where wolves had been present for 4-6 years, and highest where wolves had been present for 12-13 years. Two plant species exhibited significantly greater reproduction where wolves were present for 12-13 years. Mean leaf size of indicator plants was significantly greater in areas where wolves were present for 12-13 years, as compared with that in areas where wolves were not present or were present for …

Experimental Evolution Of An Alternating Uni- And Multicellular Life Cycle In Chlamydomonas Reinhardtii, William C. Ratcliff, Matthew D. Herron, Kathryn Howell, Jennifer T. Pentz, Frank Rosenzweig, Michael Travisano

Biological Sciences Faculty Publications

The transition to multicellularity enabled the evolution of large, complex organisms, but early steps in this transition remain poorly understood. Here we show that multicellular complexity, including development from a single cell, can evolve rapidly in a unicellular organism that has never had a multicellular ancestor. We subject the alga Chlamydomonas reinhardtii to conditions that favour multicellularity, resulting in the evolution of a multicellular life cycle in which clusters reproduce via motile unicellular propagules. While a single-cell genetic bottleneck during ontogeny is widely regarded as an adaptation to limit among-cell conflict, its appearance very early in this transition suggests that …

Filopodia As Sensors, Carol A. Heckman, H. K. Plummer

Biological Sciences Faculty Publications

Filopodia are sensors on both excitable and non-excitable cells. The sensing function is well documented in neurons and blood vessels of adult animals and is obvious during dorsal closure in embryonic development. Nerve cells extend neurites in a bidirectional fashion with growth cones at the tips where filopodia are concentrated. Their sensing of environmental cues underpins the axon's ability to "guide," bypassing non-target cells and moving toward the target to be innervated. This review focuses on the role of filopodia structure and dynamics in the detection of environmental cues, including both the extracellular matrix (ECM) and the surfaces of neighboring …

Sequestration And Scavenging Of Iron In Infection, Nermi Lee Parrow, Robert E. Fleming, Michael F. Minnick

Biological Sciences Faculty Publications

The proliferative capability of many invasive pathogens is limited by the bioavailability of iron. Pathogens have thus developed strategies to obtain iron from their host organisms. In turn, host defense strategies have evolved to sequester iron from invasive pathogens. This review explores the mechanisms employed by bacterial pathogens to gain access to host iron sources, the role of iron in bacterial virulence, and iron-related genes required for the establishment or maintenance of infection. Host defenses to limit iron availability for bacterial growth during the acute-phase response and the consequences of iron overload conditions on susceptibility to bacterial infection are also …

Tossing The Coin For Half Life, William L. Romine

Biological Sciences Faculty Publications

No abstract provided.

Bacterial Endophytes Enhance Competition By Invasive Plants, Marnie E. Rout, Thomas H. Chrzanowski, Tara K. Westlie, Thomas H. Deluca, Ragan M. Callaway, William E. Holben

Biological Sciences Faculty Publications

• Premise of the study: Invasive plants can alter soil microbial communities and profoundly alter ecosystem processes. In the invasive grass Sorghum halepense, these disruptions are consequences of rhizome-associated bacterial endophytes. We describe the effects of N₂-fixing bacterial strains from S. halepense (Rout and Chrzanowski, 2009) on plant growth and show that bacteria interact with the plant to alter soil nutrient cycles, enabling persistence of the invasive.
• Methods: We assessed fluxes in soil nutrients for ~4 yr across a site invaded by S. halepense. We assayed the N₂-fixing bacteria in vitro for phosphate solubilization, …

The Science (And Pseudoscience) Of Dna Profiling, Dan E. Krane

Biological Sciences Faculty Publications

No abstract provided.

An Acid Test For G Proteins, Stephen R. Sprang

Biological Sciences Faculty Publications

Heterotrimeric G proteins are cytoplasmic transducers of signals generated by ligandactivated 7-transmembrane receptors (G protein-coupled receptors, or GPCRs) embedded in the plasma membranes of cells. GPCRs activate G proteins by catalyzing exchange of GDP for GTP at the alpha subunit (Gα) with the concomitant release of the Gβγ heterodimer. Separately or together Gα•GTP and Gβγ stimulate enzymes that produce second messengers (e.g. cyclic AMP), control ion channels, Ras-family G proteins and regulate transcription (Cabrera-Vera et al., 2003). In yeast, GPCRs intercept mating pheromones and monitor extracellular glucose concentration, and so generate intracellular signals either to arrest growth or to proliferate. …

Neurotensin And Cholecystokinin Contract Gallbladder Circular Muscle In Chickens, Teresa F. Degolier, D. R. Brown, Gary E. Duke, M. M. Palmer, J. R. Swenson, Robert E. Carraway

Biological Sciences Faculty Publications

The contractile effects of neurotensin (NT) and cholecystokinin octapeptide (CCK-8) on isolated circular smooth muscle strips of chicken gallbladder were investigated. The NT (0.25-300 nM) produced concentration-dependent contractions on smooth muscle with an EC50 of 8.5 nM (95% confidence limits = 5.3-13.6 nM). In comparison, CCK-8 produced concentration-dependent contractions with an EC50 of 13 nM (95% confidence limits of 9-20 nM). There were no statistical differences in contractile responses when comparing NT and CCK-8 at equimolar concentrations. The NT appears to act directly on smooth muscle tissue in the chicken; the contractile responses were not blocked by 10 μM atropine …

Rcytoscape: Tools For Exploratory Network Analysis, Paul Shannon, Mark L. Grimes, Burak Kutlu, Jan J. Bit, David J. Galas

Biological Sciences Faculty Publications

Background: Biomolecular pathways and networks are dynamic and complex, and the perturbations to them which cause disease are often multiple, heterogeneous and contingent. Pathway and network visualizations, rendered on a computer or published on paper, however, tend to be static, lacking in detail, and ill-equipped to explore the variety and quantities of data available today, and the complex causes we seek to understand.

Results: RCytoscape integrates R (an open-ended programming environment rich in statistical power and datahandling facilities) and Cytoscape (powerful network visualization and analysis software). RCytoscape extends Cytoscape's functionality beyond what is possible with the Cytoscape graphical user interface. …

An Inverted Repeat In The Ospc Operator Is Required For Induction In Borrelia Burgdorferi, Dan Drecktrah, Laura S. Hall, Laura L. Hoon-Hanks, D. Scott Samuels

Biological Sciences Faculty Publications

Borrelia burgdorferi, the spirochete that causes Lyme disease, differentially regulates synthesis of the outer membrane lipoprotein OspC to infect its host. OspC is required to establish infection but then repressed in the mammal to avoid clearance by the adaptive immune response. Inverted repeats (IR) upstream of the promoter have been implicated as an operator to regulate ospC expression. We molecularly dissected the distal inverted repeat (dIR) of the ospC operator by site-directed mutagenesis at its endogenous location on the circular plasmid cp26. We found that disrupting the dIR but maintaining the proximal IR prevented induction of OspC synthesis by …

Starvation-Associated Genome Restructuring Can Lead To Reproductive Isolation In Yeast, Evgueny Kroll, Scott Coyle, Barbara Dunn, Gregory Koniges, Anthony Aragon, Jeremy Edwards, Frank Rosenzweig

Biological Sciences Faculty Publications

Knowledge of the mechanisms that lead to reproductive isolation is essential for understanding population structure and speciation. While several models have been advanced to explain post-mating reproductive isolation, experimental data supporting most are indirect. Laboratory investigations of this phenomenon are typically carried out under benign conditions, which result in low rates of genetic change unlikely to initiate reproductive isolation. Previously, we described an experimental system using the yeast Saccharomyces cerevisiae where starvation served as a proxy to any stress that decreases reproduction and/or survivorship. We showed that novel lineages with restructured genomes quickly emerged in starved populations, and that these …