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Full-Text Articles in Life Sciences

Reproduction, Embryonic Development, And Maternal Transfer Of Contaminants In The Amphibian Gastrophryne Carolinensis, William Alexander Hopkins, Sarah Elizabeth Durant, Brandon Patrick Staub, Christopher Lee Rowe, Brian Phillip Jackson Dec 2006

Reproduction, Embryonic Development, And Maternal Transfer Of Contaminants In The Amphibian Gastrophryne Carolinensis, William Alexander Hopkins, Sarah Elizabeth Durant, Brandon Patrick Staub, Christopher Lee Rowe, Brian Phillip Jackson

Open Dartmouth: Faculty Open Access Scholarship

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or development in amphibians. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial ...


Evidence That Talin Alternative Splice Variants From Ciona Intestinalis Have Different Roles In Cell Adhesion, Richard H. Singiser, Richard O. Mccann Dec 2006

Evidence That Talin Alternative Splice Variants From Ciona Intestinalis Have Different Roles In Cell Adhesion, Richard H. Singiser, Richard O. Mccann

Molecular and Cellular Biochemistry Faculty Publications

BACKGROUND: Talins are large, modular cytoskeletal proteins found in animals and amoebozoans such as Dictyostelium discoideum. Since the identification of a second talin gene in vertebrates, it has become increasingly clear that vertebrate Talin1 and Talin2 have non-redundant roles as essential links between integrins and the actin cytoskeleton in distinct plasma membrane-associated adhesion complexes. The conserved C-terminal I/LWEQ module is important for talin function. This structural element mediates the interaction of talins with F-actin. The I/LWEQ module also targets mammalian Talin1 to focal adhesion complexes, which are dynamic multicomponent assemblies required for cell adhesion and cell motility. Although ...


Vulnerability Of Pathogenic Biofilms To Micavibrio Aeruginosavorus, Daniel Kadouri, Nel C. Venzon, George A. O'Toole Nov 2006

Vulnerability Of Pathogenic Biofilms To Micavibrio Aeruginosavorus, Daniel Kadouri, Nel C. Venzon, George A. O'Toole

Open Dartmouth: Faculty Open Access Scholarship

The host specificity of the gram-negative exoparasitic predatory bacterium Micavibrio aeruginosavorus was examined. M. aeruginosavorus preyed on Pseudomonas aeruginosa, as previously reported, as well as Burkholderia cepacia, Klebsiella pneumoniae, and numerous clinical isolates of these species. In a static assay, a reduction in biofilm biomass was observed as early as 3 hours after exposure to M. aeruginosavorus, and an ∼100-fold reduction in biofilm cell viability was detected following a a 24-h exposure to the predator. We observed that an initial titer of Micavibrio as low as 10 PFU/well or a time of exposure to the predator as short as ...


The Allantois And Chorion, When Isolated Before Circulation Or Chorio-Allantoic Fusion, Have Hematopoietic Potential, Brandon M. Zeigler, Daisuke Sugiyama, Michael Chen, Yalin Guo, K. M. Downs, N. A. Speck Nov 2006

The Allantois And Chorion, When Isolated Before Circulation Or Chorio-Allantoic Fusion, Have Hematopoietic Potential, Brandon M. Zeigler, Daisuke Sugiyama, Michael Chen, Yalin Guo, K. M. Downs, N. A. Speck

Open Dartmouth: Faculty Open Access Scholarship

The chorio-allantoic placenta forms through the fusion of the allantois (progenitor tissue of the umbilical cord), with the chorionic plate. The murine placenta contains high levels of hematopoietic stem cells, and is therefore a stem cell niche. However, it is not known whether the placenta is a site of hematopoietic cell emergence, or whether hematopoietic cells originate from other sites in the conceptus and then colonize the placenta. Here, we show that the allantois and chorion, isolated prior to the establishment of circulation, have the potential to give rise to myeloid and definitive erythroid cells following explant culture. We further ...


The Role Of Mapks In B Cell Receptor-Induced Down-Regulation Of Egr-1 In Immature B Lymphoma Cells, Jiyuan Ke, Murali Gururajan, Anupam Kumar, Alan Simmons, Lilia Turcios, Ralph Lakshman Chelvarajan, David M. Cohen, David L. Wiest, John G. Monroe, Subbarao Bondada Oct 2006

The Role Of Mapks In B Cell Receptor-Induced Down-Regulation Of Egr-1 In Immature B Lymphoma Cells, Jiyuan Ke, Murali Gururajan, Anupam Kumar, Alan Simmons, Lilia Turcios, Ralph Lakshman Chelvarajan, David M. Cohen, David L. Wiest, John G. Monroe, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Cross-linking of the B cell receptor (BCR) on the immature B lymphoma cell line BKS-2 induces growth inhibition and apoptosis accompanied by rapid down-regulation of the immediate-early gene egr-1. In these lymphoma cells, egr-1 is expressed constitutively and has a prosurvival role, as Egr-1-specific antisense oligonucleotides or expression of a dominant-negative inhibitor of Egr-1 also prevented the growth of BKS-2 cells. Moreover, enhancement of Egr-1 protein with phorbol 12-myristate 13-acetate or an egr-1 expression vector rescued BKS-2 cells from BCR signal-induced growth inhibition. Nuclear run-on and mRNA stability assays indicated that BCR-derived signals act at the transcriptional level to reduce ...


Dictyostelium Myosin-Ie Is A Fast Molecular Motor Involved In Phagocytosis, Ulrike Durrwang, Setsuko Fujita-Becker, Muriel Erent, F. Jon Kull Oct 2006

Dictyostelium Myosin-Ie Is A Fast Molecular Motor Involved In Phagocytosis, Ulrike Durrwang, Setsuko Fujita-Becker, Muriel Erent, F. Jon Kull

Open Dartmouth: Faculty Open Access Scholarship

Class I myosins are single-headed motor proteins, implicated in various motile processes including organelle translocation, ion-channel gating, and cytoskeleton reorganization. Here we describe the cellular localization of myosin-IE and its role in the phagocytic uptake of solid particles and cells. A complete analysis of the kinetic and motor properties of Dictyostelium discoideum myosin-IE was achieved by the use of motor domain constructs with artificial lever arms. Class I myosins belonging to subclass IC like myosin-IE are thought to be tuned for tension maintenance or stress sensing. In contrast to this prediction, our results show myosin-IE to be a fast motor ...


Cd80 And Cd86 Control Antiviral Cd8+ T-Cell Function And Immune Surveillance Of Murine Gammaherpesvirus 68, Shinichiro Fuse, Joshua J. Obar, Sarah Bellfy, Erica K. Leung, Weijun Zhang, Edward J. Usherwood Sep 2006

Cd80 And Cd86 Control Antiviral Cd8+ T-Cell Function And Immune Surveillance Of Murine Gammaherpesvirus 68, Shinichiro Fuse, Joshua J. Obar, Sarah Bellfy, Erica K. Leung, Weijun Zhang, Edward J. Usherwood

Open Dartmouth: Faculty Open Access Scholarship

The interactions between CD80 and CD86 on antigen-presenting cells and CD28 on T cells serve as an important costimulatory signal in the activation of T cells. Although the simplistic two-signal hypothesis has been challenged in recent years by the identification of different costimulators, this classical pathway has been shown to significantly impact antiviral humoral and cellular immune responses. How the CD80/CD86-CD28 pathway affects the control of chronic or latent infections has been less well characterized. In this study, we investigated its role in antiviral immune responses against murine gammaherpesvirus 68 (MHV-68) and immune surveillance using CD80/CD86−/− mice. In ...


Gammaherpesvirus Persistence Alters Key Cd8 T-Cell Memory Characteristics And Enhances Antiviral Protection, Joshua J. Obar, Shinichiro Fuse, Erica K. Leung, Sarah C. Bellfy, Edward J. Usherwood Sep 2006

Gammaherpesvirus Persistence Alters Key Cd8 T-Cell Memory Characteristics And Enhances Antiviral Protection, Joshua J. Obar, Shinichiro Fuse, Erica K. Leung, Sarah C. Bellfy, Edward J. Usherwood

Open Dartmouth: Faculty Open Access Scholarship

In herpesvirus infections, the virus persists for life but is contained through T-cell-mediated immune surveillance. How this immune surveillance operates is poorly understood. Recent studies of other persistent infections have indicated that virus persistence is associated with functional deficits in the CD8(+) T-cell response. To test whether this is the case in a herpesvirus infection, we used a mutant murine gammaherpesvirus that is defective in its ability to persist in the host. By comparing the immune response to this virus with a revertant virus that can persist, we were able to dissect the changes in the antiviral CD8(+) T-cell response ...


Gene Order Data From A Model Amphibian (Ambystoma): New Perspectives On Vertebrate Genome Structure And Evolution, Jeramiah J. Smith, S. Randal Voss Aug 2006

Gene Order Data From A Model Amphibian (Ambystoma): New Perspectives On Vertebrate Genome Structure And Evolution, Jeramiah J. Smith, S. Randal Voss

Biology Faculty Publications

BACKGROUND: Because amphibians arise from a branch of the vertebrate evolutionary tree that is juxtaposed between fishes and amniotes, they provide important comparative perspective for reconstructing character changes that have occurred during vertebrate evolution. Here, we report the first comparative study of vertebrate genome structure that includes a representative amphibian. We used 491 transcribed sequences from a salamander (Ambystoma) genetic map and whole genome assemblies for human, mouse, rat, dog, chicken, zebrafish, and the freshwater pufferfish Tetraodon nigroviridis to compare gene orders and rearrangement rates.

RESULTS: Ambystoma has experienced a rate of genome rearrangement that is substantially lower than mammalian ...


Disruption Of Orofacial Movement Topographies In Congenic Mutants With Dopamine D5 But Not D4 Receptor Or Darpp-32 Transduction 'Knockout', Katsunori Tomiyama, Yasuyuki Makihara, Hiroshi Yamamoto, Gerard J. O'Sullivan, Rachel E. Nally, Orna Tighe, Anthony Kinsella, Allen A. Fienberg, David K. Grandy, David R. Sibley, David T. Croke, Noriaki Koshikawa, John L. Waddington Aug 2006

Disruption Of Orofacial Movement Topographies In Congenic Mutants With Dopamine D5 But Not D4 Receptor Or Darpp-32 Transduction 'Knockout', Katsunori Tomiyama, Yasuyuki Makihara, Hiroshi Yamamoto, Gerard J. O'Sullivan, Rachel E. Nally, Orna Tighe, Anthony Kinsella, Allen A. Fienberg, David K. Grandy, David R. Sibley, David T. Croke, Noriaki Koshikawa, John L. Waddington

Molecular and Cellular Therapeutics Articles

The role of D(1)-like [D(1), D(5)] and D(2)-like [D(2), D(3), D(4)] dopamine receptors and dopamine transduction via DARPP-32 in topographies of orofacial movement was assessed in restrained mice with congenic D(4) vs. D(5) receptor vs. DARPP-32 'knockout'. D(4) and DARPP-32 mutants evidenced no material phenotype; also, there were no alterations in topographical responsivity to either the selective D(2)-like agonist RU 24213 or the selective D(1)-like agonist SK and F 83959. In contrast, D(5) mutants evidenced an increase in spontaneous vertical jaw movements, which ...


The Interaction Of Bacterial Pathogens With Platelets., J Ross Fitzgerald, Timothy J. Foster, Dermot Cox Jun 2006

The Interaction Of Bacterial Pathogens With Platelets., J Ross Fitzgerald, Timothy J. Foster, Dermot Cox

Molecular and Cellular Therapeutics Articles

In recent years, the frequency of serious cardiovascular infections such as endocarditis has increased, particularly in association with nosocomially acquired antibiotic-resistant pathogens. Growing evidence suggests a crucial role for the interaction of bacteria with human platelets in the pathogenesis of cardiovascular infections. Here, we review the nature of the interactions between platelets and bacteria, and the role of these interactions in the pathogenesis of endocarditis and other cardiovascular diseases.


An Essential Role For Endocytosis Of Rhodopsin Through Interaction Of Visual Arrestin With The Ap-2 Adaptor, Nicholas R. Orem, Luxi Xia, Patrick J. Dolph May 2006

An Essential Role For Endocytosis Of Rhodopsin Through Interaction Of Visual Arrestin With The Ap-2 Adaptor, Nicholas R. Orem, Luxi Xia, Patrick J. Dolph

Open Dartmouth: Faculty Open Access Scholarship

Previously, we have identified a class of retinal degeneration mutants in Drosophila in which the normally transient interaction between arrestin2 (Arr2) and rhodopsin is stabilized and the complexes are rapidly internalized into the cell body by receptor-mediated endocytosis. The accumulation of protein complexes in the cytoplasm eventually results in photoreceptor cell death. We now show that the endocytic adapter protein AP-2 is essential for rhodopsin endocytosis through an Arr2-AP-2beta interaction, and mutations in Arr2 that disrupt its interaction with the beta subunit of AP-2 prevent endocytosis-induced retinal degeneration. We further demonstrate that if the interaction between Arr2 and AP-2 is ...


Shelling Out For Genomics, Timothy S. Mcclintock, Charles D. Derby Apr 2006

Shelling Out For Genomics, Timothy S. Mcclintock, Charles D. Derby

Physiology Faculty Publications

A report on the symposium 'Genomic and Proteomic Approaches to Crustacean Biology' held as part of the Society for Integrative and Comparative Biology 2006 Annual Meeting, Orlando, USA, 4-8 January 2006.


Prenatal Cocaine Exposure Alters Alpha2 Receptor Expression In Adolescent Rats, Rosemarie M. Booze, David R. Wallace, Janelle M. Silvers, Barbara J. Strupp, Diane M. Snow, Charles F. Mactutus Apr 2006

Prenatal Cocaine Exposure Alters Alpha2 Receptor Expression In Adolescent Rats, Rosemarie M. Booze, David R. Wallace, Janelle M. Silvers, Barbara J. Strupp, Diane M. Snow, Charles F. Mactutus

Neuroscience Faculty Publications

BACKGROUND: Prenatal cocaine exposure produces attentional deficits which to persist through early childhood. Given the role of norepinephrine (NE) in attentional processes, we examined the forebrain NE systems from prenatal cocaine exposed rats. Cocaine was administered during pregnancy via the clinically relevant intravenous route of administration. Specifically, we measured alpha2-adrenergic receptor (alpha2-AR) density in adolescent (35-days-old) rats, using [3H]RX821002 (5 nM).

RESULTS: Sex-specific alterations of alpha2-AR were found in the hippocampus and amygdala of the cocaine-exposed animals, as well as an upregulation of alpha2-AR in parietal cortex.

CONCLUSION: These data suggest that prenatal cocaine exposure results in a persistent ...


Cbfbeta Is A Facultative Runx Partner In The Sea Urchin Embryo, Anthony J. Robertson, Carrie Dickey-Sims, Andrew Ransick, Dawn E. Rupp, John J. Mccarthy, James A. Coffman Feb 2006

Cbfbeta Is A Facultative Runx Partner In The Sea Urchin Embryo, Anthony J. Robertson, Carrie Dickey-Sims, Andrew Ransick, Dawn E. Rupp, John J. Mccarthy, James A. Coffman

Physiology Faculty Publications

BACKGROUND: Runx proteins are developmentally important metazoan transcription factors that form a heterodimeric complex with the non-homologous protein Core Binding Factor beta (CBFbeta). CBFbeta allosterically enhances Runx DNA binding but does not bind DNA itself. We report the initial characterization of SpCBFbeta, the heterodimeric partner of SpRunt-1 from the sea urchin Stronylocentrotus purpuratus.

RESULTS: SpCBFbeta is remarkably similar to its mammalian homologues, and like them it enhances the DNA binding of the Runt domain. SpCBFbeta is entirely of zygotic provenance and its expression is similar that of SpRunt-1, accumulating globally at late blastula stage then later localizing to endoderm and ...


A Pdz-Binding Motif As A Critical Determinant Of Rho Guanine Exchange Factor Function And Cell Phenotype, Miaoliang Liu, Arie Horowitz Feb 2006

A Pdz-Binding Motif As A Critical Determinant Of Rho Guanine Exchange Factor Function And Cell Phenotype, Miaoliang Liu, Arie Horowitz

Open Dartmouth: Faculty Open Access Scholarship

We identified a Rho guanine exchange factor (GEF) expressed as two splice variants, which differ only in either having or lacking a Postsynaptic density 95, Disk large, Zona occludens-1 (PDZ) motif. The PDZ adaptor protein synectin bound the longer splice variant, Syx1, which was targeted to the plasma membrane in a synectin-dependent manner. The shorter variant, Syx2, was diffusely distributed in the cytoplasm. Fluorescence resonance energy transfer (FRET) imaging revealed similar differences between the spatial patterns of active RhoA in Syx1 versus Syx2-expressing cells. Expression of Syx1 augmented endothelial cell (EC) migration and tube formation, whereas Syx2 expression did not ...


H2-M3-Restricted Cd8+ T Cells Are Not Required For Mhc Class Ib-Restricted Immunity Against Listeria Monocytogenes, Sarah E. F. D'Orazio, Christine A. Shaw, Michael N. Starnbach Feb 2006

H2-M3-Restricted Cd8+ T Cells Are Not Required For Mhc Class Ib-Restricted Immunity Against Listeria Monocytogenes, Sarah E. F. D'Orazio, Christine A. Shaw, Michael N. Starnbach

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Studies using major histocompatibility complex (MHC)-Ia–deficient mice have shown that MHC-Ib–restricted CD8+ T cells can clear infections caused by intracellular pathogens such as Listeria monocytogenes. M3-restricted CD8+ T cells, which recognize short hydrophobic N-formylated peptides, appear to comprise a substantial portion of the MHC-Ib–restricted T cell response in the mouse model of L. monocytogenes infection. In this study, we isolated formyltransferase (fmt) mutant strains of L. monocytogenes that lacked the ability to add formyl groups to nascent polypeptides. These fmt mutant Listeria strains did not produce antigens that could be recognized by M3-restricted T cells ...


Type 3 Deiodinase Is Critical For The Maturation And Function Of The Thyroid Axis, Arturo Hernandez, M. Elena Martinez, Steven Flering, Valerie Anne Galton, Donald St. German Feb 2006

Type 3 Deiodinase Is Critical For The Maturation And Function Of The Thyroid Axis, Arturo Hernandez, M. Elena Martinez, Steven Flering, Valerie Anne Galton, Donald St. German

Open Dartmouth: Faculty Open Access Scholarship

Developmental exposure to appropriate levels of thyroid hormones (THs) in a timely manner is critical to normal development in vertebrates. Among the factors potentially affecting perinatal exposure of tissues to THs is type 3 deiodinase (D3). This enzyme degrades THs and is highly expressed in the pregnant uterus, placenta, and fetal and neonatal tissues. To determine the physiological role of D3, we have generated a mouse D3 knockout model (D3KO) by a targeted inactivating mutation of the Dio3 gene in mouse ES cells. Early in life, D3KO mice exhibit delayed 3,5,3′-triiodothyronine (T3) clearance, a markedly elevated serum ...


Rab-10 Is Required For Endocytic Recycling In The Caenorhabditis Elegans Intestine, Carlos Chih-Hsiung Chen, Peter J. Schweinsberg, Shilpa Vashist, Darren P. Mareiniss, Eric J. Lambie, Barth D. Grant Jan 2006

Rab-10 Is Required For Endocytic Recycling In The Caenorhabditis Elegans Intestine, Carlos Chih-Hsiung Chen, Peter J. Schweinsberg, Shilpa Vashist, Darren P. Mareiniss, Eric J. Lambie, Barth D. Grant

Open Dartmouth: Faculty Open Access Scholarship

The endocytic pathway of eukaryotes is essential for the internalization and trafficking of macromolecules, fluid, membranes, and membrane proteins. One of the most enigmatic aspects of this process is endocytic recycling, the return of macromolecules (often receptors) and fluid from endosomes to the plasma membrane. We have previously shown that the EH-domain protein RME-1 is a critical regulator of endocytic recycling in worms and mammals. Here we identify the RAB-10 protein as a key regulator of endocytic recycling upstream of RME-1 in polarized epithelial cells of the Caenorhabditis elegans intestine. rab-10 null mutant intestinal cells accumulate abnormally abundant RAB-5-positive early ...


Predation And Cathemerality. Comparing The Impact Of Predators On The Activity Patterns Of Lemurids And Ceboids., Ian C. Colquhoun Jan 2006

Predation And Cathemerality. Comparing The Impact Of Predators On The Activity Patterns Of Lemurids And Ceboids., Ian C. Colquhoun

Anthropology Publications

The removal, or absence, of predatory species could be a contributing proximate factor to the rise of primate cathemerality. But predators themselves can also be cathemeral, so cathemerality could well be an evolutionary stable strategy. From a comparative perspective, it appears that the effect of predatory species cannot provide a unitary explanation for cathemerality. Varying distributions and population densities of predators, especially raptors, may be key factors in owl monkey (Aotus) cathemerality, but temperature and lunar cycle variation have also been implicated. In Madagascar, while raptors are potential predators of lemur species, the cathemerality of Eulemur species coincides with that ...


The Ethics Of Wildlife Control In Humanized Landscapes, John Hadidian, Camilla H. Fox, William S. Lynn Jan 2006

The Ethics Of Wildlife Control In Humanized Landscapes, John Hadidian, Camilla H. Fox, William S. Lynn

Ecology Collection

The 21st century is witness to an unprecedented and rapid growth of human settlements, from urban centers to wilderness vacation resorts. Concurrent with this has been the growing tolerance and acceptance of many wild animals and humans for one another. This has created an expanding ‘zone’ of human-animal contacts, some number of which invariably result in conflicts. While the vast majority of our interactions with wild animals are undoubtedly benign, it is the conflict between wildlife and people that draws particularly close attention from the public. Animals viewed as vertebrate “pests” range from the small to the large, the timid ...


Real Time Single Cell Analysis Of Bid Cleavage And Bid Translocation During Caspase-Dependent And Neuronal Caspase-Independent Apoptosis., Manus W. Ward, Markus Rehm, Heiko Düssmann, Slavomir Kacmar, Caoimhin G. Concannon, Jochen Hm Prehn Jan 2006

Real Time Single Cell Analysis Of Bid Cleavage And Bid Translocation During Caspase-Dependent And Neuronal Caspase-Independent Apoptosis., Manus W. Ward, Markus Rehm, Heiko Düssmann, Slavomir Kacmar, Caoimhin G. Concannon, Jochen Hm Prehn

Physiology and Medical Physics Articles

Bcl-2 homology domain (BH) 3-only proteins couple stress signals to evolutionarily conserved mitochondrial apoptotic pathways. Caspase 8-mediated cleavage of the BH3-only protein Bid into a truncated protein (tBid) and subsequent translocation of tBid to mitochondria has been implicated in death receptor signaling. We utilized a recombinant fluorescence resonance energy transfer (FRET) Bid probe to determine the kinetics of Bid cleavage and tBid translocation during death receptor-induced apoptosis in caspase 3-deficient MCF-7 cells. Cells treated with tumor necrosis factor-alpha (200 ng/ml) showed a rapid cleavage of the Bid-FRET probe occurring 75.4 +/- 12.6 min after onset of the tumor ...