Biology Commons^™

Geographical Distributions, Relative Abundance And Coexistence Of Drosophila Aldrichi And Drosophila Buzzatii In Australia, J. S.F. Barker, Robert A. Krebs, H. I. Davies

Biological, Geological, and Environmental Faculty Publications

Climatic data and collection records for the cactophilic Drosophila aldrichi and Drosophila buzzatii for 97 localities were used to examine the effects of geographical location, season, host plant species and climatic factors on their range and relative abundance. Temporal variation in relative abundance was assessed from monthly collections over 4 years at one locality. Effects of weather variables over the 28 days before each collection were examined. A generalized linear model of the spatial data showed significant geographical variation in relative abundance, and significant climatic effects, with the proportion of D. aldrichi higher in the warm season, and increasing as …

Genetic Analysis Of Two Bile Salt Hydrolase Activities In Lactobacillus Acidophilus Ncfm, Olivia Mcauliffe, Raul J. Cano, Todd R. Klaenhammer

Biological Sciences

Two genes, bshA and bshB, encoding bile salt hydrolase enzymes (EC 3.5.1.24) were identified in the genome sequence of Lactobacillus acidophilus NCFM. Targeted inactivation of these genes via chromosomal insertion of an integration vector demonstrated different substrate specificities for these two enzymes.

Elevated Levels Of Trace Elements In Cores Of Otoliths And Their Potential For Use As Natural Tags, Benjamin I. Ruttenberg, Scott L. Hamilton, Michael J.H. Hickford, Georges L. Paradis, Michael S. Sheehy, Julie D. Standish, Ofer Ben-Tzvi, Robert R. Warner

Biological Sciences

Variation in the chemical composition of fish otoliths has been used in recent years to address a range of ecological questions, including levels of stock mixing, variation in habitat use, and rates of larval exchange. While some of these questions have been answered with varying success, the degree to which discrete populations are connected via larval exchange remains unknown. To identify larval sources using natural variation in otolith chemistry, we must distinguish and measure the chemical composition of the otolith core, the portion of the otolith formed at the spawning site. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), …

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 …

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 …

Feasibility For Utilization Of A Freshwater Pulmonate Snail, Physa Acuta, As A Model Organism For Environmental Toxicity Testing, With Special Reference To Cadmium Ion Toxicity, Valerie Woodard

Biology Dissertations - Archive

The benefits of developing the pond snail, Physa acuta, as a model species for testing acute and chronic toxicity of aquatic pollutants include its wide North American distribution, ease of field collection and laboratory maintenance, and efficacy in testing toxicity responses including mortality, crawling behavior, reproduction and metabolism under both field and laboratory conditions. Mortality, as 50 % sample lethal concentration (LC50) and 50 % sample lethal time (LT50) values with increased cadmium chloride (CdCl2) concentration in both acute 192 h and chronic 672 h tests. A new endpoint of 50 % sample crawl-out response (CO50) proved to be a …

Use Of Reovirus Monoreassortants To Define Lysis Of Transfomed Cells, Christine Nora Mutsoli

Biology Theses - Archive

Reovirus is known to selectively destroy transformed cells while establishing a persistent infection in normal cells. For this study the transformed cell lines used were L929, WI-38 VA13 2RA, T1, N1, and MYC-3. Additionally, the normal cells WI-38 and MMEC were used to examine differential sensitivity to reovirus serotypes 1, 2, and 3. Reovirus is able to replicate efficiently in L929 cells because it induces a transition from capped to uncapped translation of viral mRNA. Reovirus maintains a persistent infection in WI-38 cells, but lyses WI-38 VA13 2RA cells. Reovirus has also been demonstrated to lyse and produce more virus …

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 …

Hedgehog Regulated Slit Expression Determines Commissure And Glial Cell Position In The Zebrafish Forebrain, Michael J.F. Barresi, Lara D. Hutson, Chi Bin Chien, Rolf O. Karlstrom

Biological Sciences: Faculty Publications

Three major axon pathways cross the midline of the vertebrate forebrain early in embryonic development: the postoptic commissure (POC), the anterior commissure (AC) and the optic nerve. We show that a small population of Gfap+ astroglia spans the midline of the zebrafish forebrain in the position of, and prior to, commissural and retinal axon crossing. These glial 'bridges' form in regions devoid of the guidance molecules slit2 and slit3, although a subset of these glial cells express slit1a. We show that Hh signaling is required for commissure formation, glial bridge formation, and the restricted expression of the guidance molecules slit1a, …

Digenic Control Of Colouration In The Two-Spot Gourami Trichogaster Trichopterus Trichopterus, Jack Frankel

Department of Biology Faculty Publications

Labyrinth  fishes  of  the  families  Anabantidae,  Belontiidae,Helostomatidae,  and  Osphronemidae  comprise the  tradi-tional  anabantoids,  a  group  of  about  80  relatively  small African  and  southeast  Asian  species (Linke  1991).  Many of  the  anabantoids  are  popular  with  aquarium  hobbyists because of their interesting reproductive behaviours, with males of most species brooding eggs in their mouths or in floating bubble nests (Vevers 1980; Linke 1991; Axelrod and Vorderwinkler 1995; Mills 2000). They have also beenthe focus of several environmental, morphological, and gene-tic  investigations  (Sommer  1982;  Gosline  1985;  Waki-yama  et  al. 1997;  Frankel  1992,  2001).  The  two-spot gourami,   Trichogaster  trichopterus  trichopterus  Pallas (Osphronemidae),  is  one …

Group 13 Hox Proteins Interact With The Mh2 Domain Of R-Smads And Modulate Smad Transcriptional Activation Functions Independent Of Hox Dna Binding Capability, Thomas M. Williams, Melissa E. Williams, Joanne H. Heaton, Thomas D. Gelehrter, Jeffrey W. Innis

Biology Faculty Publications

Interactions with co-factors provide a means by which HOX proteins exert specificity. To identify candidate protein interactors of HOXA13, we created and screened an E11.5–E12.5, distal limb bud yeast two-hybrid prey library. Among the interactors, we isolated the BMP-signaling effector Smad5, which interacted with the paralogous HOXD13 but not with HOXA11 or HOXA9, revealing unique interaction capabilities of the AbdB-like HOX proteins. Using deletion mutants, we determined that the MH2 domain of Smad5 is necessary for HOXA13 interaction.

This is the first report demonstrating an interaction between HOX proteins and the MH2 domain of Smad proteins. HOXA13 and HOXD13 …

Ecology Of The Plankton Of Lakes Wapalanne And Ocquittunk In Sussex County, New Jersey, Malgorzata Barbara Drazek-Falah

Theses, Dissertations and Culminating Projects

The diversity of planktonic organisms was studied for seven months in Lake Wapalanne and Lake Ocquittunk (Stokes State Forest), Sussex County, New Jersey. Relative abundance and species diversity were studied as well as water quality including parameters: temperature, pH, dissolved oxygen, conductivity and depth of lakes. The data of seasonal changes in abundance of organisms and water quality was compared between both lakes.

Three stations were set up along the straight line on Lake Wapalanne, buoyed by diatometers, which were used for diatom collection. There were also three stations located along the sides of Lake Ocquittunk arbitrary picked. Plankton samples …

"Sibling Species, Advertisement Calls, And Reproductive Isolation In Frogs Of The Leptodactylus Pentadactylus Species Cluster (Amphibia, Leptodactylidae), W. Ronald Heyer, Rafael O. De Sá, A. Rettig

Biology Faculty Publications

A recent re-evaluation of morphological and advertisement call variation in the large species of frogs of the Leptodactylus pentadactylus cluster discovered more examples of sibling species as defined by Ernst Mayr in his influential book Animal Species and Evolution. All previously documented instances of sibling species in frogs demonstrated advertisement call differentiation consistent with the calls serving as pre-mating isolating mechanisms. However, we find one instance of two species with nondistinguishable adult morphologies as well as nondistinguishable advertisement calls. Presumably, the new instances of sibling species reflect retention of ancestral adult morphologies and advertisement calls. Larval and habitat differentiation appear …

Immune-Endocrine Interactions In The Lizard Sceloporus Undulatus Hyacinthinus: Testing An Assumption Of The Immunocompetence Handicap Hypothesis, Mukta Chakraborty

All-Inclusive List of Electronic Theses and Dissertations

The immunocompetence handicap hypothesis (IHH) was proposed by Folstad and Karter ( 1992) to describe the role of the endocrine system in ensuring honesty of sexual signaling. Numerous studies have investigated the assumptions of the IHH, but currently there is mixed evidential support in favor of the IHH. The first chapter of this thesis is a review examinining these studies, their limitations, and proposed alternative models and future directions. The second chapter of this thesis presents a study in which we experimentally assesss the testosterone immunosuppression assumption in adult male Sceloporus undulatus lizards. We manipulated circulating androgen levels (Day 0) …

Ascidians Of South Padre Island, Texas, With A Key To Species, Gretchen Lambert, Zen Faulkes, Charles C. Lambert, Virginia L. Scofield

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The ascidians of South Padre Island, Texas were surveyed in August 2004. Because the subtidal area is limited to soft sediments, the survey was restricted to marina floats and pilings, harbor buoys, boat hulls and other artificial substrates which offer suitable attachment surfaces for ascidians. Fifteen species were documented, with multiple species representing each of the three orders of ascidians. None of the species found in this survey are native, suggesting they were all introduced through boat traffic. About half the species were found in a reproductive state, however, indicating that they have established local breeding populations.

Determining The Phylogenetic Relationship Of A Collection Of Hydra Strains And Species Using The Mitochondrial Genes : Lrrna, Trna-Trp And Coii, Jacob Zuckman

Theses, Dissertations and Culminating Projects

The discovery of the mitochondrial DNA (mtDNA) in the early 1960’s ushered in the field of organellar genetics. Evidence from both genetic and physical techniques has demonstrated that mtDNA are generally circular in structure, and that they represent the vestigial structure of the ancestral prokaryotic endosymbiont genome (Nosek et al., 1998). The more than 90 vertebrates and invertebrates sequenced to date have been found to have a remarkably constant gene content. With few exceptions, each contains the genes for 13 energy pathway proteins, the 2 RNA components of mitochondrial ribosomes (23S and 16S rRNA), and 22 transfer RNAs (Pont-Kingdon et …

Habitat-Specific Diet Of The Mottled Sculpin And Its Impact On Benthic Invertebrate Community Structure, Brendan M. Earl

Masters Theses

The relationships between predators and their prey are important and influential components in the structure of ecological communities. These interactions not only impact the species involved, but can also have a wide range of direct and indirect effects that resonate throughout the community. In Michigan trout streams, one of the main predators of benthic invertebrates is the mottled sculpin (Cottus bairdi) whose diet and selective predation may influence benthic invertebrate community structure. Using gastric lavage, the stomach contents of sculpins from both erosional and depositional habitats were collected and analyzed to determine the main prey types, prey preference, …

A Mechanistic Explanation For Global Patterns Of Liana Abundance And Distribution, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

One of the main goals in ecology is determining the mechanisms that control the abundance and distribution of organisms. Using data from 69 tropical forests worldwide, I demonstrate that liana (woody vine) abundance is correlated negatively with mean annual precipitation and positively with seasonality, a pattern precisely the opposite of most other plant types. I propose a general mechanistic hypothesis integrating both ecological and ecophysiological approaches to explain this pattern. Specifically, the deep root and efficient vascular systems of lianas enable them to suffer less water stress during seasonal droughts while many competitors are dormant, giving lianas a competitive advantage …

Patterns, Causes And Consequences Of Regional Variation In The Ecology And Life History Of A Reef Fish, Benjamin I. Ruttenberg, Alison J. Haupt, Angel I. Chiriboga, Robert R. Warner

Biological Sciences

Many species vary in their ecology across their geographic ranges in response to gradients in environmental conditions. Such variation, which can influence life history traits and subsequent demography of populations, usually occurs over large spatial scales. However, describing and understanding the causes of such variation is difficult precisely because it occurs over such large spatial scales. In this study, we document spatial variation in the ecology of a common reef fish, Stegastes beebei, in the Gala´pagos Islands and test a number of potential causal mechanisms. The pattern resembles that seen in latitudinal variation: individuals are larger, occur in higher densities, …

Reaction Of Tardigrades (Hypsibius) To Physical And Chemical Extremes, Limor Raz

Theses and Dissertations

The process of cryptobiosis is characterized by a complete state of body water dehydration and undetectable metabolic activity, which allows tardigrades {Hypsibius) to escape environmental stress when conditions become unfavorable. In our research, Hypsibius was tested in a laboratory under pH levels of 3 to 10 and a salinity concentration gradient. In the pH experiment, we placed tardigrades in petri dishes with agar solution in an experimental pH and measured the average distance traveled. We expected them to respond favorably to a neutral pH of 7 which is common in most living organisms by showing increased movement. In the salinity …

Photochemical Transformations Of Riverine Dissolved Organic Matter: Effects On Estuarine Bacterial Metabolism And Nutrient Demand, Erik M. Smith, Ronald Benner

Faculty Publications

By experimentally simulating the exposure of terrigenous dissolved organic matter (DOM) to sunlight during the mixing of river water and seawater in an estuary (St. Helena Sound, South Carolina), this study examined how photochemical alterations may affect both the magnitude and fate of DOM utilization by estuarine bacteria. In a series of experiments performed with water samples collected from 3 blackwater rivers draining into an estuary of the South Atlantic Bight (USA), exposure to light resulted in significant decreases in dissolved organic carbon (DOC) concentration and DOM absorption at 350 nm relative to dark controls. When these water samples were …

Adaptive Sampling Of Phytoplankton Responses To Episodic Physical Forcing In The Nearshore Coastal Ocean, Mark A. Moline

Biological Sciences

The original proposal focused on the linkages between in-water physical, biological and optical dynamics and to assess the degree to which remote sensing could be applied. These areas were approached during the 2001 sampling season and with follow on studies, as part of the extension of the grant through the PECASE award, there are three specific areas of work that have evolved from these original efforts. The first is a further examination of the coherence between convergence zones, general current patterns and spatial distribution of in-water biological signals (phytoplankton). The second is a remote sensing focus, attempting to define the …

Calmodulin And Pf6 Are Components Of A Complex That Localizes To The C1 Microtubule Of The Flagellar Central Apparatus, Matthew J. Wargo, Erin E. Dymek, Elizabeth F. Smith

Dartmouth Scholarship

Studies of flagellar motility in Chlamydomonas mutants lacking specific central apparatus components have supported the hypothesis that the inherent asymmetry of this structure provides important spatial cues for asymmetric regulation of dynein activity. These studies have also suggested that specific projections associated with the C1 and C2 central tubules make unique contributions to modulating motility; yet, we still do not know the identities of most polypeptides associated with the central tubules. To identify components of the C1a projection, we took an immunoprecipitation approach using antibodies generated against PF6. The pf6 mutant lacks the C1a projection and possesses flagella that only …

Effects Of Oxidative Stress On Ascidia Interrupta Embryogenesis, Anna Stwora, Virginia L. Scofield, Zen Faulkes

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Discussion: Oxidative stress does not affect very early development, which is consistent with the "be prepared" hypothesis (Epel, 2003). Two possible hypotheses could explain this result. The"be prepared" hypothesis suggests that very early embryos have static but short-lived anti-oxidant defensive mechanism in place, such as enzymes that neutralize hydrogen peroxide...

Origin Of The Eumetazoa: Testing Ecological Predictions Of Molecular Clocks Against The Proterozoic Fossil Record, Kevin J. Peterson, Nicholas J. Butterfield

Dartmouth Scholarship

Molecular clocks have the potential to shed light on the timing of early metazoan divergences, but differing algorithms and calibration points yield conspicuously discordant results. We argue here that competing molecular clock hypotheses should be testable in the fossil record, on the principle that fundamentally new grades of animal organization will have ecosystem-wide impacts. Using a set of seven nuclear-encoded protein sequences, we demonstrate the paraphyly of Porifera and calculate sponge/eumetazoan and cnidarian/bilaterian divergence times by using both distance [minimum evolution (ME)] and maximum likelihood (ML) molecular clocks; ME brackets the appearance of Eumetazoa between 634 and 604 Ma, whereas …

Great Lakes Coastal Wetland Fragmentation: Edge Effects On Zooplankton, Macroinvertebrate, And Larval Fish Communities, Keto F. Gyekis

Masters Theses

Wetlands are some of the most diverse and ecologically important habitats in the world. Although wetlands have been plagued by anthropogenic destruction and disturbance, there is a general lack of knowledge regarding how fragmentation affects these systems. During the summer of 2004 and the spring and summer of 2005,1 investigated edge effects associated with anthropogenic fragmentation in 25 fringing marshes of Lakes Michigan and Huron. Environmental data, microcrustacean zooplankton, aquatic macroinvertebrates, and larval fish were collected along transects extending into each marsh from reference (natural) and anthropogenic (artificial) edges. Bulrush stems of Great Lakes fringing marshes attenuated the influx and …

Bats Of Skydusky Hollow, Bland County, Virginia, Virgil Brack Jr., Richard J. Reynolds, Wil Orndorff, Joe Zokaites, Carol Zokaites

Virginia Journal of Science

During the period 22 November 1999 – 11 October 2001, winter hibernacula surveys, spring staging/autumn swarming surveys, and summer surveys for bats were completed in caves of Skydusky Hollow, Bland County, Virginia. During winter, 12 caves were entered and 16,185 bats counted: 235 Myotis sodalis (Indiana bat), 14,475 Myotis lucifugus (little brown myotis), 12 Myotis septentrionalis (northern myotis), 7 Myotis leibii (eastern small-footed myotis), 1,441 Pipistrellus subflavus (eastern pipistrelle), and 15 Eptesicus fuscus (big brown bat). Myotis sodalis hibernated in thermally stable areas of 7 -9 ̊C. The largest concentration of M. lucifugus (n = 4,280) hibernated in an area …

Proliferation Zones In The Salmon Telencephalon And Evidence For Environmental Influence On Proliferation Rate, Sean C. Lema, Mark J. Hodges, Michael P. Marchetti, Gabrielle A. Nevitt

Biological Sciences

Cell proliferation occurs in the brain of fish throughout life. This mitotic activity contributes new neurons to some brain subdivisions, suggesting potential for plasticity in neural development. Recently we found that the telencephalon in salmonids (salmon, trout) is significantly reduced in fish reared in hatcheries compared to wild fish, and that these differences resulted in part from rearing conditions. Here, we describe localized areas of cell proliferation in the telencephalon of juvenile coho salmon (Oncorhynchus kisutch) and begin to explore whether mitotic activity in these areas is sensitive to environmental conditions. Using the 5-bromo-2'-deoxyuridine (BrdU) cell birthdating technique, …

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). …

First Confirmed Breeding Of The Rock Wren In Minnesota, Philip C. Chu

Biology Faculty Publications

No abstract provided.