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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 …

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 …

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.

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) …

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.

A New Species Of Streptanthus (Brassicaceae) From Three Peaks In Lake County, California, Rebecca W. Dolan, Richard O'Donnell

Scholarship and Professional Work - LAS

Streptanlhus vernalis is a newly described species inhabiting serpentine rock outcrops in the Three Peaks area in Lake County, California. Morphological and allozyme data indicate that this taxon is related to the S. morrisonii complex.

Protection Against Experimental Autoimmune Myocarditis Is Mediated By Interleukin-10-Producing T Cells That Are Controlled By Dendritic Cells, Ya Li, Janet S. Heuser, Stanley D. Kosanke, Mark E. Hemric, Madeleine W. Cunningham

Faculty Publications and Presentations

Experimental autoimmune myocarditis (EAM) can be induced in the Lewis rat by cardiac myosin or its cryptic S2-16 peptide epitope (amino acids1052 to 1076). To investigate cellular mechanisms and the role of antigen-presenting cells in regulation of myocarditis, we induced protection against EAM in Lewis rats by administration of S2-16 peptide in incomplete Freund’s adjuvant (IFA). Protection to EAM was associated with activation of S2-16-reactive splenocytes secreting high levels of interleukin (IL)-10 and reduced levels of interferon- and IL-2. Adoptive transfer of S2-16:IFA-induced splenocytes producing IL-10 suppressed myocarditis induction in syngeneic recipients, suggesting their regulatory cell nature. However, exposure of …

Unpalatable Plants Protect Neighbors From Grazing And Increase Plant Community Diversity, Ragan M. Callaway, David Kikodze, Marina Chiboshvili, Liana Khetsuriani

Biological Sciences Faculty Publications

Tasty plants can be protected from herbivores by unpalatable neighbors. We used experimental exclosures, removal of unpalatable species, and transplants of palatable and unpalatable species in subalpine meadows of the Caucasus Mountains of Georgia to study the effects of two unpalatable species on plant communities. We found that Cirsium obalatum and Veratrum lobelianum, two large native perennial herbs that invade after heavy grazing, had strong facilitative effects on communities through their indirect effects on livestock herbivores. These unpalatable invaders had different effects on community composition when livestock were present than when livestock were excluded. Furthermore, removing Cirsium and Veratrum …

Asymmetrical Competition And Patterns Of Abundance Of Aedes Albopictus And Culex Pipiens (Diptera : Culicidae), Katie S. Costanzo, Kimberly Mormann, Steven A. Juliano

Faculty Publications – Biological Sciences

We tested for competitive advantage among larvae of Aedes albopictus (Skuse) and Culex pipiens L. in a laboratory experiment and determined the frequency and spatial and temporal patterns of co-occurrence in the field in East St. Louis, IL. In a laboratory competition experiment at multiple combined densities of Ae. albopictus and Cx. pipiens larvae, Ae. albopictus survivorship, and developmental times were significantly affected by conspecific densities but not by Cx. pipiens densities. In contrast, Cx. pipiens survivorship, and developmental times were significantly affected by both conspecific and Ae. albopictus densities. Per capita rate of increase (r') for Ae. albopictus cohorts …

Membrane Potential Oscillations In Reticulospinal And Spinobulbar Neurons During Locomotor Activity, James F. Einum, James T. Buchanan

Biological Sciences Faculty Research and Publications

Feedback from the spinal locomotor networks provides rhythmic modulation of the membrane potential of reticulospinal (RS) neurons during locomotor activity. To further understand the origins of this rhythmic activity, the timings of the oscillations in spinobulbar (SB) neurons of the spinal cord and in RS neurons of the posterior and middle rhombencephalic reticular nuclei were measured using intracellular microelectrode recordings in the isolated brain stem-spinal cord preparation of the lamprey. A diffusion barrier constructed just caudal to the obex allowed induction of locomotor activity in the spinal cord by bath application of an excitatory amino acid to the spinal bath. …

Evaluation Of Glycine Max Mrna Clusters, Ronald L. Frank, Fikret Erçal

Biological Sciences Faculty Research & Creative Works

Background: Clustering the ESTs from a large dataset representing a single species is a convenient starting point for a number of investigations into gene discovery, genome evolution, expression patterns, and alternatively spliced transcripts. Several methods have been developed to accomplish this, the most widely available being UniGene, a public domain collection of gene-oriented clusters for over 45 different species created and maintained by NCBI. The goal is for each cluster to represent a unique gene, but currently it is not known how closely the overall results represent that reality. UniGene's build procedure begins with initial mRNA clusters before joining ESTs. …

Review Of "The Microbial Models Of Molecular Biology: From Genes To Genomes" By R. H. Davis, Amy Cheng Vollmer, S. J. Vollmer

Biology Faculty Works

No abstract provided.

Phylogeny And Biogeography Of Ice Crawlers (Insecta: Grylloblattodea): Evidence From Six Molecular Loci, Karl J. Jarvis

Theses and Dissertations

Ice crawlers (Insecta: Grylloblattodea) are rarely encountered insects that consist of five genera representing 26 species from North America and Asia. Asian grylloblattids are the most diverse, but North American ice crawlers (genus Grylloblatta) are known for their adaptation to cold conditions. Phylogenetic relationships among grylloblattid species and genera are not known. Late Pleistocene glaciations had a major effect on the current Grylloblatta distribution, because their specific habitat requirements restrict them to small geographical areas. Six genes were sampled in 37 individuals for 18S rRNA, 28S rRNA, histone 3, 12S rRNA, 16S rRNA, and cytochrome oxidase II (COII) from 27 …

Ecotypic Variation In Phosphorus Acquisition Mechanisms Within Marine Picocyanobacteria, Lisa Moore, M. Ostrowski, D. J. Scanlan, K. Feren, T. Sweetsir

Biology

ABSTRACT: Prochlorococcus and Synechococcus are major prokaryotic primary producers in the oligotrophic oceans that may be affected by the climate-related increases in nitrogen fixation and subsequent phosphorus (P) limitation in some parts of the oceans. Evidence that Prochlorococcus populations in the North Pacific subtropical gyre (NPSG) have increased over the past decades, possibly due to having a competitive advantage under conditions of P limitation, suggests aspects of their Pphysiology that are important for dictating their in situ success. Here, we compared the physiology of P acquisition and response to P stress (indicated by alkaline phosphatase activity, APA) among isolates of …

Ecotypic Variation In Phosphorus Acquisition Mechanisms Within Marine Picocyanobacteria, Lisa Moore Phd, M. Ostrowski, D. J. Scanlan, K. Feren, T. Sweetsir

Faculty Publications

Prochlorococcus and Synechococcus are major prokaryotic primary producers in the oligotrophic oceans that may be affected by the climate-related increases in nitrogen fixation and subsequent phosphorus (P) limitation in some parts of the oceans. Evidence that Prochlorococcus populations in the North Pacific subtropical gyre (NPSG) have increased over the past decades, possibly due to having a competitive advantage under conditions of P limitation, suggests aspects of their Pphysiology that are important for dictating their in situ success. Here, we compared the physiology of P acquisition and response to P stress (indicated by alkaline phosphatase activity, APA) among isolates of Prochlorococcus …

Evaluating Forensic Dna Evidence, Dan E. Krane, William C. Thompson

Biological Sciences Faculty Publications

No abstract provided.