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Full-Text Articles in Biology

Tactical Research Fund – Asfb 2009 Workshop, Department Of Fisheries Oct 2010

Tactical Research Fund – Asfb 2009 Workshop, Department Of Fisheries

Fisheries Occasional Publications

Biodiversity of aquatic ecosystems – What to measure and monitor for fisheries and ecosystem management FRDC Project No. 2008/353.


Fall 2010, Biology @ Su, Syracuse University Biology Department Oct 2010

Fall 2010, Biology @ Su, Syracuse University Biology Department

Biology @ SU

No abstract provided.


Impact Of Interdisciplinary Undergraduate Research In Mathematics And Biology On The Development Of A New Course Integrating Five Stem Disciplines, Lester Caudill, April L. Hill, Kathy Hoke, Ovidiu Z. Lipan Oct 2010

Impact Of Interdisciplinary Undergraduate Research In Mathematics And Biology On The Development Of A New Course Integrating Five Stem Disciplines, Lester Caudill, April L. Hill, Kathy Hoke, Ovidiu Z. Lipan

Department of Math & Statistics Faculty Publications

Funded by innovative programs at the National Science Foundation and the Howard Hughes Medical Institute, University of Richmond faculty in biology, chemistry, mathematics, physics, and computer science teamed up to offer first- and second-year students the opportunity to contribute to vibrant, interdisciplinary research projects. The result was not only good science but also good science that motivated and informed course development. Here, we describe four recent undergraduate research projects involving students and faculty in biology, physics, mathematics, and computer science and how each contributed in significant ways to the conception and implementation of our new Integrated Quantitative Science course, a …


Circadian Disruption And Metabolic Disease: Findings From Animal Models, Deanna M. Arble, Kathryn Moynihan Ramsey, Joseph Bass, Fred W. Turek Oct 2010

Circadian Disruption And Metabolic Disease: Findings From Animal Models, Deanna M. Arble, Kathryn Moynihan Ramsey, Joseph Bass, Fred W. Turek

Biological Sciences Faculty Research and Publications

Social opportunities and work demands have caused humans to become increasingly active during the late evening hours, leading to a shift from the predominantly diurnal lifestyle of our ancestors to a more nocturnal one. This voluntarily decision to stay awake long into the evening hours leads to circadian disruption at the system, tissue, and cellular levels. These derangements are in turn associated with clinical impairments in metabolic processes and physiology. The use of animal models for circadian disruption provides an important opportunity to determine mechanisms by which disorganization in the circadian system can lead to metabolic dysfunction in response to …


Explaining Long-Distance Dispersal: Effects Of Dispersal Distance On Survival And Growth In A Stream Salamander, Winsor H. Lowe Oct 2010

Explaining Long-Distance Dispersal: Effects Of Dispersal Distance On Survival And Growth In A Stream Salamander, Winsor H. Lowe

Biological Sciences Faculty Publications

Long-distance dispersal (LDD) may contribute disproportionately to range expansions, the creation of new evolutionary lineages, and species persistence in human-dominated landscapes. However, because data on the individual consequences of dispersal distance are extremely limited, we have little insight on how LDD is maintained in natural populations. I used six years of spatially explicit capture–mark–recapture (CMR) data to test the prediction that individual performance increases with dispersal distance in the stream salamander Gyrinophilus porphyriticus. Dispersal distance was total distance moved along the 1-km study stream, ranging from 0 to 565 m. To quantify individual performance, I used CMR estimates of …


Capture Of Ungulates In Central Asia Using Drive Nets: Advantages And Pitfalls Illustrated By The Endangered Mongolian Saiga Saiga Tatarica Mongolica, Joel Berger, Kim M. Murray, Bayarbaatar Buuveibaatar, Michael R. Dunbar, Badamjav Lkhagvasuren Oct 2010

Capture Of Ungulates In Central Asia Using Drive Nets: Advantages And Pitfalls Illustrated By The Endangered Mongolian Saiga Saiga Tatarica Mongolica, Joel Berger, Kim M. Murray, Bayarbaatar Buuveibaatar, Michael R. Dunbar, Badamjav Lkhagvasuren

Biological Sciences Faculty Publications

The study of mammals suffering intense poaching in remote areas poses an increasingly difficult conservation challenge, in part because the extreme flightiness of such species complicates safe capture. The benefits of handling (an opportunity to obtain biological information and attach radio collars) must be weighed against stress to the animals and potential capture-related mortality. In parts of Central Asia this problem is not trivial, as populations have been heavily harvested and opportunities for restraint are often limited. Mongolian saiga Saiga tatarica mongolica, being both Endangered and poached, typifies these issues. Here we describe capture protocols for adult females handled quickly …


Broadly Sampled Multigene Analyses Yield A Well-Resolved Eukaryotic Tree Of Life, Laura Wegener Parfrey, Jessica Grant, Yonas I. Tekle, Erica Lasek-Nesselquist, Hilary G. Morrison, Mitchell L. Sogin, David J. Patterson, Laura A. Katz Oct 2010

Broadly Sampled Multigene Analyses Yield A Well-Resolved Eukaryotic Tree Of Life, Laura Wegener Parfrey, Jessica Grant, Yonas I. Tekle, Erica Lasek-Nesselquist, Hilary G. Morrison, Mitchell L. Sogin, David J. Patterson, Laura A. Katz

Biological Sciences: Faculty Publications

An accurate reconstruction of the eukaryotic tree of life is essential to identify the innovations underlying the diversity of microbial and macroscopic (e.g., plants and animals) eukaryotes. Previous work has divided eukaryotic diversity into a small number of high-level "supergroups," many of which receive strong support in phylogenomic analyses. However, the abundance of data in phylogenomic analyses can lead to highly supported but incorrect relationships due to systematic phylogenetic error. Furthermore, the paucity of major eukaryotic lineages (19 or fewer) included in these genomic studies may exaggerate systematic error and reduce power to evaluate hypotheses. Here, we use a taxon-rich …


Essential Genes For Astroglial Development And Axon Pathfinding During Zebrafish Embryogenesis, Michael J.F. Barresi, Sean Burton, Kristina Dipietrantonio, Adam Amsterdam, Nancy Hopkins, Rolf O. Karlstrom Oct 2010

Essential Genes For Astroglial Development And Axon Pathfinding During Zebrafish Embryogenesis, Michael J.F. Barresi, Sean Burton, Kristina Dipietrantonio, Adam Amsterdam, Nancy Hopkins, Rolf O. Karlstrom

Biological Sciences: Faculty Publications

The formation of the central nervous system depends on the coordinated development of neural and glial cell types that arise from a common precursor. Using an existing group of zebrafish mutants generated by viral insertion, we performed a "shelf-screen" to identify genes necessary for astroglial development and axon scaffold formation. We screened 274 of 315 viral insertion lines using antibodies that label axons (anti-Acetylated Tubulin) and astroglia (anti-Gfap) and identified 25 mutants with defects in gliogenesis, glial patterning, neurogenesis, and axon guidance. We also identified a novel class of mutants affecting radial glial cell numbers. Defects in astroglial patterning were …


Impact Of Interdisciplinary Undergraduate Research In Mathematics And Biology On The Development Of A New Course Integrating Five Stem Disciplines, Lester Caudill, April L. Hill, Kathy Hoke, Ovidiu Z. Lipan Oct 2010

Impact Of Interdisciplinary Undergraduate Research In Mathematics And Biology On The Development Of A New Course Integrating Five Stem Disciplines, Lester Caudill, April L. Hill, Kathy Hoke, Ovidiu Z. Lipan

Biology Faculty Publications

Funded by innovative programs at the National Science Foundation and the Howard Hughes Medical Institute, University of Richmond faculty in biology, chemistry, mathematics, physics, and computer science teamed up to offer first- and second-year students the opportunity to contribute to vibrant, interdisciplinary research projects. The result was not only good science but also good science that motivated and informed course development. Here, we describe four recent undergraduate research projects involving students and faculty in biology, physics, mathematics, and computer science and how each contributed in significant ways to the conception and implementation of our new Integrated Quantitative Science course, a …


Dorsal Eye Selector Pannier (Pnr) Suppresses The Eye Fate To Define Dorsal Margin Of The Drosophila Eye, Sarah M. Oros, Meghana Tare, Madhuri Kango-Singh, Amit Singh Oct 2010

Dorsal Eye Selector Pannier (Pnr) Suppresses The Eye Fate To Define Dorsal Margin Of The Drosophila Eye, Sarah M. Oros, Meghana Tare, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

Axial patterning is crucial for organogenesis. During Drosophila eye development, dorso-ventral (DV) axis determination is the first lineage restriction event. The eye primordium begins with a default ventral fate, on which the dorsal eye fate is established by expression of the GATA-1 transcription factor pannier (pnr). Earlier, it was suggested that loss of pnr function induces enlargement in the dorsal eye due to ectopic equator formation. Interestingly, we found that in addition to regulating DV patterning, pnr suppresses the eye fate by downregulating the core retinal determination genes eyes absent (eya), sine oculis (so) and dacshund (dac) to define the …


Reversible Deficiencies In Flagellar Beating And Axonemal Assembly, Mei Wei Oct 2010

Reversible Deficiencies In Flagellar Beating And Axonemal Assembly, Mei Wei

Dissertations (1934 -)

Axonemal complexes in flagella are largely prepackaged in the cell body. As such, one mutation often results in the absence of the co-assembled components and permanent motility deficiencies. For example, a Chlamydomonas mutant defective in RSP4 in the radial spoke, which is critical for bend propagation, has paralyzed flagella that also lack the paralogue RSP6 and three additional radial spoke proteins. Intriguingly, recent studies showed that several mutant strains contain a mixed population of swimmers and paralyzed cells despite their identical genetic background. Here we report a cause underlying these variations. Two new mutants lacking RSP6 swim processively and other …


Development Of Predatory Behavior In Juvenile Fish: Evidence Of Attraction To Prey Chemical Alarm Cues By Naïve Coral Reef Predator, (Pseudochromis Fuscus), Shannon Odell Oct 2010

Development Of Predatory Behavior In Juvenile Fish: Evidence Of Attraction To Prey Chemical Alarm Cues By Naïve Coral Reef Predator, (Pseudochromis Fuscus), Shannon Odell

Independent Study Project (ISP) Collection

Chemical alarm cues and their function on the coal reef has become an area of increasing interest in the study of predator-prey dynamics (Smith 1999, Friesen and Chivers 2006, Holmes and McCormick 2010). One prominent question in understanding the evolutionary basis for the development of chemical alarm cues is determining how these cues benefit the sender directly (Chivers 1996). One way chemical alarm cues found in freshwater systems have been found to benefit the sender of the cue is through attraction of secondary predators to the chemical alarm cue, which then interfere with the primary attack and increase chances of …


"Beyond Bio2010: Celebration And Opportunities" At The Intersection Of Mathematics And Biology, John R. Jungck, Holly D. Gaff, Adam P. Fagen, Jay B. Labov Oct 2010

"Beyond Bio2010: Celebration And Opportunities" At The Intersection Of Mathematics And Biology, John R. Jungck, Holly D. Gaff, Adam P. Fagen, Jay B. Labov

Biological Sciences Faculty Publications

With this special edition of CBE-LSE, which focuses on connections between and integration of the biological and mathematical sciences, it is especially fitting that we report on an important symposium, Beyond BIO2010: Celebration and Opportunities,1 which was held at the National Acad- emy of Sciences (NAS) in Washington, D.C. on May 21–22, 2010. This symposium was organized to assess what progress has been made in addressing the challenges and recommendations in the National Research Council’s (NRC) report: BIO2010: Transforming Undergraduate Education for Future Research Biologists (NRC, 2003a). Most of the presen- tations and posters at this event emphasized the increasing …


Mathematical Manipulative Models: In Defense Of "Beanbag Biology", John R. Jungck, Holly Gaff, Anton E. Weisstein Oct 2010

Mathematical Manipulative Models: In Defense Of "Beanbag Biology", John R. Jungck, Holly Gaff, Anton E. Weisstein

Biological Sciences Faculty Publications

Mathematical manipulative models have had a long history of influence in biological research and in secondary school education, but they are frequently neglected in undergraduate biology education. By linking mathematical manipulative models in a four-step process-1) use of physical manipulatives, 2) interactive exploration of computer simulations, 3) derivation of mathematical relationships from core principles, and 4) analysis of real data sets-we demonstrate a process that we have shared in biological faculty development workshops led by staff from the BioQUEST Curriculum Consortium over the past 24 yr. We built this approach based upon a broad survey of literature in mathematical educational …


Selective Biochlorination Of Hydroxyquinolines By A Flavin-Dependent Halogenase, Fuchao Xu, Amanda Merkley, Dayu Yu, Jixun Zhan Oct 2010

Selective Biochlorination Of Hydroxyquinolines By A Flavin-Dependent Halogenase, Fuchao Xu, Amanda Merkley, Dayu Yu, Jixun Zhan

Biological Engineering Faculty Publications

Rdc2 is a flavin-dependent halogenase from Pochonia chlamydosporia. Through the introduction of a His6-tag to both the N- and C-termini, the isolation yield of Rdc2 from Escherichia coli using Ni-NTA affinity chromatography was increased by three-fold. In vitro reaction of Rdc2 and a flavin reductase (Fre) with seven different hydroxyquinolines revealed that 3-hydroxyquinoline (3), 5-hydroxyquinoline (5), 6-hydroxyquinoline (6), and 7-hydroxyquinoline (7) can be specifically halogenated. These products were prepared by incubating the corresponding substrates with IPTG-induced E. coli BL21(DE3)/Rdc2. They were respectively characterized as 3-hydroxy-4-chloroquinoline (3a), 5-hydroxy-6-chloroquinoline (5a), 5-chloro-6-hydroxyquinoline (6a), and 7-hydroxy-8-chloroquinoline (7a) by NMR and MS …


Role Of Ampk Throughout Meiotic Maturation In The Mouse Oocyte: Evidence For Promotion Of Polar Body Formation And Suppression Of Premature Activation, Stephen M. Downs, Ru Ya, Christopher C. Davis Oct 2010

Role Of Ampk Throughout Meiotic Maturation In The Mouse Oocyte: Evidence For Promotion Of Polar Body Formation And Suppression Of Premature Activation, Stephen M. Downs, Ru Ya, Christopher C. Davis

Biological Sciences Faculty Research and Publications

This study was conducted to assess the role of AMPK in regulating meiosis in mouse oocytes from the germinal vesicle stage to metaphase II. Exposure of mouse cumulus cell-enclosed oocytes (CEO) and denuded oocytes (DO) during spontaneous maturation in vitro to AMPK-activating agents resulted in augmentation of the rate and frequency of polar body formation. Inhibitors of AMPK had an opposite, inhibitory effect. In addition, the AMPK inhibitor, compound C (Cmpd C) increased the frequency of oocyte activation. The stimulatory action of the AMPK-activating agent, AICAR, and the inhibitory action of Cmpd C were diminished if exposure was delayed, indicating …


Post‐Glacial Expansion Into The Paleozoic Plateau: Evidence Of An Ozarkian Refugium For The Ozark Minnow Notropis Nubilus (Teleostei: Cypriniformes), Peter B. Berendzen, J.F. Dugan, Tony Gamble Oct 2010

Post‐Glacial Expansion Into The Paleozoic Plateau: Evidence Of An Ozarkian Refugium For The Ozark Minnow Notropis Nubilus (Teleostei: Cypriniformes), Peter B. Berendzen, J.F. Dugan, Tony Gamble

Biological Sciences Faculty Research and Publications

Genetic variation was examined within the Ozark minnow Notropis nubilus using complete mtDNA cytochrome b gene sequences from 160 individuals representing 30 localities to test hypotheses on the origin of the distribution. Phylogenetic analyses revealed three strongly supported clades of haplotypes consistent with geographic distributions: a clade from the Western Ozarks, a clade from the Southern Ozarks and a clade from the Northern Ozarks and upper Mississippi River basin. The estimated mean ages of these clades indicated that they diverged during pre-Illinoian glacial cycles extending from the late Pliocene into the early Pleistocene. Results of demographic analyses based on coalescent …


Identification Of An Archaeal Presenilin-Like Intramembrane Protease, Celia Torres-Arancivia, Carolyn M. Ross, Jose Chavez, Zahra Assur, Georgia Dolios, Filippo Mancia, Iban Ubarretxena-Belandia Sep 2010

Identification Of An Archaeal Presenilin-Like Intramembrane Protease, Celia Torres-Arancivia, Carolyn M. Ross, Jose Chavez, Zahra Assur, Georgia Dolios, Filippo Mancia, Iban Ubarretxena-Belandia

Publications and Research

Background: The GXGD-type diaspartyl intramembrane protease, presenilin, constitutes the catalytic core of the c-secretase multi-protein complex responsible for activating critical signaling cascades during development and for the production of b-amyloid peptides (Ab) implicated in Alzheimer’s disease. The only other known GXGD-type diaspartyl intramembrane proteases are the eukaryotic signal peptide peptidases (SPPs). The presence of presenilin-like enzymes outside eukaryots has not been demonstrated. Here we report the existence of presenilin-like GXGD-type diaspartyl intramembrane proteases in archaea.

Methodology and Principal Findings: We have employed in vitro activity assays to show that MCMJR1, a polytopic membrane protein from the archaeon Methanoculleus marisnigri JR1, …


Drug Off-Target Effects Predicted Using Structural Analysis In The Context Of A Metabolic Network Model, Roger L. Chang, Lei Xie, Philip E. Bourne, Bernhard O. Palsson Sep 2010

Drug Off-Target Effects Predicted Using Structural Analysis In The Context Of A Metabolic Network Model, Roger L. Chang, Lei Xie, Philip E. Bourne, Bernhard O. Palsson

Publications and Research

Recent advances in structural bioinformatics have enabled the prediction of protein-drug off-targets based on their ligand binding sites. Concurrent developments in systems biology allow for prediction of the functional effects of system perturbations using large-scale network models. Integration of these two capabilities provides a framework for evaluating metabolic drug response phenotypes in silico. This combined approach was applied to investigate the hypertensive side effect of the cholesteryl ester transfer protein inhibitor torcetrapib in the context of human renal function. A metabolic kidney model was generated in which to simulate drug treatment. Causal drug off-targets were predicted that have previously been …


Long-Term Isolation Of A Highly Mobile Seabird On The Galapagos, Patricia Parker, Frank Hailer, E.A. Schreiber, Joshua Miller, Iris Levin, R. Chesser, Robert Fleischer Sep 2010

Long-Term Isolation Of A Highly Mobile Seabird On The Galapagos, Patricia Parker, Frank Hailer, E.A. Schreiber, Joshua Miller, Iris Levin, R. Chesser, Robert Fleischer

Biology Department Faculty Works

The Galapagos Islands are renowned for their high degree of endemism. Marine taxa inhabiting the archipelago might be expected to be an exception, because of their utilization of pelagic habitats—the dispersal barrier for terrestrial taxa—as foraging grounds. Magnificent frigatebirds (Fregata magnificens) have a highly vagile lifestyle and wide geographical distribution around the South and Central American coasts. Given the potentially high levels of gene flow among populations, the species provides a good test of the effectiveness of the Galapagos ecosystem in isolating populations of highly dispersive marine species. We studied patterns of genetic (mitochondrial DNA, microsatellites and nuclear introns) and …


Physical Interaction Between Vivid And White Collar Complex Regulates Photoadaptation In Neurospora, Chen-Hui H. Chen, Bradley S. Demay, Amy S. Gladfelter, Jay Dunlap, Jennifer J. Loros Sep 2010

Physical Interaction Between Vivid And White Collar Complex Regulates Photoadaptation In Neurospora, Chen-Hui H. Chen, Bradley S. Demay, Amy S. Gladfelter, Jay Dunlap, Jennifer J. Loros

Dartmouth Scholarship

Photoadaptation, the ability to attenuate a light response on prolonged light exposure while remaining sensitive to escalating changes in light intensity, is essential for organisms to decipher time information appropriately, yet the underlying molecular mechanisms are poorly understood. In Neurospora crassa, VIVID (VVD), a small LOV domain containing blue-light photoreceptor protein, affects photoadaptation for most if not all light-responsive genes. We report that there is a physical interaction between VVD and the white collar complex (WCC), the primary blue-light photoreceptor and the transcription factor complex that initiates light-regulated transcriptional responses in Neurospora. Using two previously characterized VVD mutants, we show …


Biological Computation, Melanie Mitchell Sep 2010

Biological Computation, Melanie Mitchell

Computer Science Faculty Publications and Presentations

In this article, the term biological computation refers to the proposal that living organisms themselves perform computations, and, more specifically, that the abstract ideas of information and computation may be key to understanding biology in a more unified manner. It is important to point out that the study of biological computation is typically not the focus of the field of computational biology, which applies computing tools to the solution of specific biological problems. Likewise, biological computation is distinct from the field of biologically-inspired computing, which borrows ideas from biological systems such as the brain, insect colonies, and the immune system …


The Role Of Puf3p And Puf4p In The Regulation Of Mrna Decay In Yeast Saccharomyces Cerevisiae, Florencia Andrea Lopez Leban Sep 2010

The Role Of Puf3p And Puf4p In The Regulation Of Mrna Decay In Yeast Saccharomyces Cerevisiae, Florencia Andrea Lopez Leban

Dissertations

Proper regulation of gene expression at a cellular level is required in all organisms for their successful adaptation and survival to physiological or environmental changes. In eukaryotes, a convenient way of regulating gene expression is achieved by post-transcriptionally adjusting the decay rates of different mRNAs. The Puf family of proteins in yeast belong to a widespread group of eukaryotic RNA-binding proteins that regulate the lifespans of target mRNAs by sequence specifically binding to 3' untranslated regions (UTRs) and modulating their decay rates. For example, the yeast Puf3 protein binds the COX17 3' UTR, stimulating its deadenylation and subsequent decay. However, …


Site Fidelity And Population Structure Of A Solitary Subterranean Rodent, Geomys Breviceps, In Southwestern Arkansas., Kimberly Nicole King Sep 2010

Site Fidelity And Population Structure Of A Solitary Subterranean Rodent, Geomys Breviceps, In Southwestern Arkansas., Kimberly Nicole King

Theses and Dissertations

From October 2007 to April 2010, 87 Geomys breviceps were captured a total of 156 times on a 2-ha plot in southwestern Arkansas. Individuals were captured using the Sikes-Finley pocket gopher trap and all new captures were marked with passive integrated transponder (PIT) tags. Spatial distribution and movement patterns were examined using ArcGIS. The population was female biased. Average duration between initial capture and final recapture of individuals was 8 months. An individual male and female captured at the onset of the study were recaptured after 29 months and remained within 46 m of their initial capture site. Males were …


Aromatic Acid Metabolites Of Escherichia Coli K-12 Can Induce The Marrab Operon, Lon Chubiz, Christopher Rao Sep 2010

Aromatic Acid Metabolites Of Escherichia Coli K-12 Can Induce The Marrab Operon, Lon Chubiz, Christopher Rao

Biology Department Faculty Works

MarR is a key regulator of the marRAB operon involved in antibiotic resistance and solvent stress tolerance in Escherichia coli. We show that two metabolic intermediates, 2,3-dihydroxybenzoate and anthranilate, involved in enterobactin and tryptophan biosynthesis, respectively, can activate marRAB transcription. We also found that a third intermediate involved in ubiquinone biosynthesis, 4-hydroxybenzoate, activates marRAB transcription in the absence of TolC. Of the three, however, only 2,3-dihydroxybenzoate directly binds MarR and affects its activity.


Prolonged Space Flight-Induced Alterations In The Structure And Function Of Human Skeletal Muscle Fibres, Robert H. Fitts, S. W. Trappe, David R. Costill, Philip M. Gallagher, Andrew C. Creer, Patricia A. Colloton, Jim R. Peters, Janell Romatowski, J. L. Bain, Danny A. Riley Sep 2010

Prolonged Space Flight-Induced Alterations In The Structure And Function Of Human Skeletal Muscle Fibres, Robert H. Fitts, S. W. Trappe, David R. Costill, Philip M. Gallagher, Andrew C. Creer, Patricia A. Colloton, Jim R. Peters, Janell Romatowski, J. L. Bain, Danny A. Riley

Biological Sciences Faculty Research and Publications

The primary goal of this study was to determine the effects of prolonged space flight (~180 days) on the structure and function of slow and fast fibres in human skeletal muscle. Biopsies were obtained from the gastrocnemius and soleus muscles of nine International Space Station crew members ~45 days pre- and on landing day (R+0) postflight. The main findings were that prolonged weightlessness produced substantial loss of fibre mass, force, and power with the hierarchy of the effects being soleus type I > soleus type II > gastrocnemius type I > gastrocnemius type II. Structurally, the quantitatively most important adaptation was fibre atrophy …


Repression Of Wnt Signaling By A Fer-Type Nonreceptor Tyrosine Kinase, Aaron P. Putzke, Joel H. Rothman Sep 2010

Repression Of Wnt Signaling By A Fer-Type Nonreceptor Tyrosine Kinase, Aaron P. Putzke, Joel H. Rothman

Faculty Publications

The Wnt signaling pathway must be properly modulated to ensure an appropriate output: pathological conditions result from either insufficient or excessive levels of Wnt signal. For example, hyperactivation of the Wnt pathway is associated with various cancers and subnormal Wnt signaling can lead to increased invasiveness of tumor cells. We found that the Caenorhabditis elegans ortholog of the Fer nonreceptor tyrosine kinase, FRK-1, limits Wnt signaling by preventing the adhesion complex-associated beta-catenin, HMP-2, from participating in Wnt-dependent specification of the endoderm during embryogenesis. Removal of FRK-1 function results in relocalization of HMP-2 to the nucleus of epidermal cells, and allows …


Glutamine Synthetase Partitioning In Native And Introduced Salt Marsh Grasses, Eric L.G. Hazelton, Thomas J. Knight Phd, Theresa A. Theodose Phd Sep 2010

Glutamine Synthetase Partitioning In Native And Introduced Salt Marsh Grasses, Eric L.G. Hazelton, Thomas J. Knight Phd, Theresa A. Theodose Phd

Faculty Publications

Plants with higher glutamine synthetase (GS) activity in photosynthetic tissues than below-ground structures (high leaf:root [L:R] GS activity) show growth advantages over plants with a low L:R GS activity ratio. The benefits of a high L:R GS activity ratio are well documented in agricultural systems, but little is known about the ecology of GS partitioning in natural systems. To determine the ecological significance of GS partitioning, we measured above- and below-ground GS activity in Spartina grasses field-collected from a Maine salt marsh and others raised in a growth chamber from seed. The more stress-tolerant, faster growing S. alterniflora had a …


Nutrient Cycling In Impacted Stream Ecosystems: From Microbes To Watersheds, David James Van Horn Sep 2010

Nutrient Cycling In Impacted Stream Ecosystems: From Microbes To Watersheds, David James Van Horn

Biology ETDs

The conditions found in stream ecosystems are an integration of watershed characteristics and processes. Anthropogenic disturbances are part of this integration and include direct inputs to streams, alteration of riparian areas, and modification of catchment properties which affect material inputs. Impacts to discrete portions of terrestrial watersheds combine as water moves down gradient, transporting the byproducts of catchment disturbances to streams including, nutrients, organic materials, particulates, and toxins. This dissertation explores the effects of disturbance on nutrient cycling in stream ecosystems at three spatial scales: the patch scale includes localized processes and assemblages, the reach scale encompasses tens to hundreds …


The Identity Of The Crackling, Luminescent Frog Of Suriname (Rana Typhonia Linnaeus, 1758) (Amphibia, Anura), E. O. Lavilla, José A. Langone, José M. Padial, Rafael O. De Sá Sep 2010

The Identity Of The Crackling, Luminescent Frog Of Suriname (Rana Typhonia Linnaeus, 1758) (Amphibia, Anura), E. O. Lavilla, José A. Langone, José M. Padial, Rafael O. De Sá

Biology Faculty Publications

Review of the literature and recently available field notes from the collector of the type allows a reconsideration of the identity of the Linnaean name Rana typhonia. We provide evidence to demonstrate that the Linnaean species is neither a bufonid nor an Asiatic ranid, but a Neotropical hylid. Subsequently, we consider Rana typhonia as an older synonym of Rana venulosa Laurenti, 1768, redescribing its holotype under the new combination, Trachycephalus typhonius (Linnaeus, 1758).