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Articles 271 - 300 of 340

Full-Text Articles in Biology

Tasting Phenylthiocarbamide (Ptc): A New Integrative Genetics Lab With An Old Flavor, Robert B. Merritt, Lou Ann Bierwert, Barton Slatko, Michael P. Weiner, Jessica Ingram, Kristianna Sciarra, Evan Weiner May 2008

Tasting Phenylthiocarbamide (Ptc): A New Integrative Genetics Lab With An Old Flavor, Robert B. Merritt, Lou Ann Bierwert, Barton Slatko, Michael P. Weiner, Jessica Ingram, Kristianna Sciarra, Evan Weiner

Biological Sciences: Faculty Publications

First reported in the early 1930s, variation in the ability to taste phenylthiocarbamide (PTC) has since become one of the most widely studied of all human genetic traits. Guo and Reed (2001) provide an excellent review of work on this polymorphism prior to the identification and sequencing of the PTC gene by Kim et al. (2003), and Wooding (2006) provides a stimulating historical review of the role various scientists have played in the study of PTC taste sensitivity and the importance of these studies in relation to natural selection. Identification of the PTC gene and a number of subsequent …

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Human Cardiac-Specific Cdna Array For Idiopathic Dilated Cardiomyopathy: Sex-Related Differences, Georges E. Haddad, Lori J. Saunders, Seth D. Crosby, Maria Carles, Federica Del Monte, Kindra King, Michael R. Bristow, Francis G. Spinale, Thomas E. Macgillivray, Marc J. Semigran, G. William Dec, Steven A. Williams, Roger J. Hajjar, Judith K. Gwathmey Apr 2008

Human Cardiac-Specific Cdna Array For Idiopathic Dilated Cardiomyopathy: Sex-Related Differences, Georges E. Haddad, Lori J. Saunders, Seth D. Crosby, Maria Carles, Federica Del Monte, Kindra King, Michael R. Bristow, Francis G. Spinale, Thomas E. Macgillivray, Marc J. Semigran, G. William Dec, Steven A. Williams, Roger J. Hajjar, Judith K. Gwathmey

Biological Sciences: Faculty Publications

Idiopathic dilated cardiomyopathy (IDCM) constitutes a large portion of patients with heart failure of unknown etiology. Up to 50% of all transplant recipients carry this clinical diagnosis. Female-specific gene expression in IDCM has not been explored. We report sex-related differences in the gene expression profile of ventricular myocardium from patients undergoing cardiac transplantation. We produced and sequenced subtractive cDNA libraries, using human left ventricular myocardium obtained from male transplant recipients with IDCM and nonfailing human heart donors. With the resulting sequence data, we generated a custom human heart failure microarray for IDCM containing 1,145 cardiac-specific oligonucleotide probes. This array was …

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The Dynamic Nature Of Eukaryotic Genomes, Laura Wegener Parfrey, Daniel J.G. Lahr, Laura A. Katz Apr 2008

The Dynamic Nature Of Eukaryotic Genomes, Laura Wegener Parfrey, Daniel J.G. Lahr, Laura A. Katz

Biological Sciences: Faculty Publications

Analyses of diverse eukaryotes reveal that genomes are dynamic, sometimes dramatically so. In numerous lineages across the eukaryotic tree of life, DNA content varies within individuals throughout life cycles and among individuals within species. Discovery of examples of genome dynamism is accelerating as genome sequences are completed from diverse eukaryotes. Though much is known about genomes in animals, fungi, and plants, these lineages represent only 3 of the 60-200 lineages of eukaryotes. Here, we discuss diverse genomic strategies in exemplar eukaryotic lineages, including numerous microbial eukaryotes, to reveal dramatic variation that challenges established views of genome evolution. For example, in …

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The Homodimeric Kinesin, Kif17, Is Essential For Vertebrate Photoreceptor Sensory Outer Segment Development, Christine Insinna, Narendra Pathak, Brian Perkins, Iain Drummond, Joseph C. Besharse Apr 2008

The Homodimeric Kinesin, Kif17, Is Essential For Vertebrate Photoreceptor Sensory Outer Segment Development, Christine Insinna, Narendra Pathak, Brian Perkins, Iain Drummond, Joseph C. Besharse

Neuroscience: Faculty Publications

Sensory cilia and intraflagellar transport (IFT), a pathway essential for ciliogenesis, play important roles in embryonic development and cell differentiation. In vertebrate photoreceptors IFT is required for the early development of ciliated sensory outer segments (OS), an elaborate organelle that sequesters the many proteins comprising the phototransduction machinery. As in other cilia and flagella, heterotrimeric members of the kinesin 2 family have been implicated as the anterograde IFT motor in OS. However, in Caenorhabditis elegans, OSM-3, a homodimeric kinesin 2 motor, plays an essential role in some, but not all sensory cilia. Kif17, a vertebrate OSM-3 homologue, is known for …

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Broadly Sampled Multigene Trees Of Eukaryotes, Hwan Su Yoon, Jessica Grant, Yonas I. Tekle, Min Wu, Benjamin C. Chaon, Jeffrey C. Cole, John M. Logsdon, David J. Patterson, Debashish Bhattacharya, Laura A. Katz Feb 2008

Broadly Sampled Multigene Trees Of Eukaryotes, Hwan Su Yoon, Jessica Grant, Yonas I. Tekle, Min Wu, Benjamin C. Chaon, Jeffrey C. Cole, John M. Logsdon, David J. Patterson, Debashish Bhattacharya, Laura A. Katz

Biological Sciences: Faculty Publications

Background. Our understanding of the eukaryotic tree of life and the tremendous diversity of microbial eukaryotes is in flux as additional genes and diverse taxa are sampled for molecular analyses. Despite instability in many analyses, there is an increasing trend to classify eukaryotic diversity into six major supergroups: the 'Amoebozoa', 'Chromalveolata', 'Excavata', 'Opisthokonta', 'Plantae', and 'Rhizaria'. Previous molecular analyses have often suffered from either a broad taxon sampling using only single-gene data or have used multigene data with a limited sample of taxa. This study has two major aims: (1) to place taxa represented by 72 sequences, 61 of which …

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An Unidentified Filarial Species And Its Impact On Fitness In Wild Populations Of The Black-Footed Ferret (Mustela Nigripes), Samantha M. Wisely, Jo Gayle Howard, Steven A. Williams, Odile Bain, Rachel M. Santymire, Katherine D. Bardsley, Elizabeth S. Williams Jan 2008

An Unidentified Filarial Species And Its Impact On Fitness In Wild Populations Of The Black-Footed Ferret (Mustela Nigripes), Samantha M. Wisely, Jo Gayle Howard, Steven A. Williams, Odile Bain, Rachel M. Santymire, Katherine D. Bardsley, Elizabeth S. Williams

Biological Sciences: Faculty Publications

Disease can threaten the restoration of endangered species directly by substantially decreasing host survival or indirectly via incremental decreases in survival and reproduction. During a biomedical survey of reintroduced populations of the highly endangered black-footed ferret from 2002 to 2005, microfilariae discovered in the blood were putatively identified as Dirofilaria immitis, and widespread screening was initiated using a commercially available antigen-based ELISA test. A subset of animals (n = 16) was screened for D. immitis using a highly sensitive PCR-based assay. Microfilariae were also molecularly and morphologically characterized. Of 198 animals at six reintroduction sites, 12% had positive results using …

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Low Temperature (23 °C) Increases Expression Of Biofilm-, Cold-Shock- And Rpos-Dependent Genes In Escherichia Coli K-12, Christine A. White-Ziegler, Suzin Um, Natalie M. Pérez, Abby L. Berns, Amy J. Malhowski, Sarah Young Jan 2008

Low Temperature (23 °C) Increases Expression Of Biofilm-, Cold-Shock- And Rpos-Dependent Genes In Escherichia Coli K-12, Christine A. White-Ziegler, Suzin Um, Natalie M. Pérez, Abby L. Berns, Amy J. Malhowski, Sarah Young

Biological Sciences: Faculty Publications

Temperature serves as a cue to regulate gene expression in Escherichia coli and other bacteria. Using DNA microarrays, we identified 297 genes whose expression is increased at 23 6C compared to 37 6C in E. coli K-12. Of these genes, 122 are RpoS-controlled, confirming genome-wide the model that low temperature serves as a primary cue to trigger the general stress response. Several genes expressed at 23 6C overlap with the cold-shock response, suggesting that strategies used to adapt to sudden shifts in temperature also mediate long-term growth at 23 6C. Another category of genes more highly expressed at 23 6C …

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The Zebrafish Fleer Gene Encodes An Essential Regulator Of Cilia Tubulin Polyglutamylation, Narendra Pathak, Tomoko Obara, Steve Mangos, Yan Liu, Iain A. Drummond Nov 2007

The Zebrafish Fleer Gene Encodes An Essential Regulator Of Cilia Tubulin Polyglutamylation, Narendra Pathak, Tomoko Obara, Steve Mangos, Yan Liu, Iain A. Drummond

Neuroscience: Faculty Publications

Cilia and basal bodies are essential organelles for a broad spectrum of functions, including the development of left-right asymmetry, kidney function, cerebrospinal fluid transport, generation of photoreceptor outer segments, and hedgehog signaling. Zebrafish fleer (flr) mutants exhibit kidney cysts, randomized left-right asymmetry, hydrocephalus, and rod outer segment defects, suggesting a pleiotropic defect in ciliogenesis. Positional cloning flr identified a tetratricopeptide repeat protein homologous to the Caenorhabditis elegans protein DYF1 that was highly expressed in ciliated cells, flr pronephric cilia were shortened and showed a reduced beat amplitude, and olfactory cilia were absent in mutants, flr cilia exhibited ultrastructural defects in …

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Draft Genome Of The Filarial Nematode Parasite Brugia Malayi, Elodie Ghedin, Shiliang Wang, David Spiro, Elisabet Caler, Qi Zhao, Jonathan Crabtree, Jonathan E. Allen, Arthur L. Delcher, David B. Guiliano, Diego Miranda-Saavedra, Samuel V. Angiuoli, Todd Creasy, Paolo Amedeo, Brian Haas, Najib M. El-Sayed, Jennifer R. Wortman, Tamara Feldblyum, Luke Tallon, Michael Schatz, Martin Shumway, Hean Koo, Steven L. Salzberg, Seth Schobel, Mihaela Pertea, Mihai Pop, Owen White, Geoffrey J. Barton, Clotilde K.S. Carlow, Michael J. Crawford, Jennifer Daub, Et Al, Steven A. Williams Sep 2007

Draft Genome Of The Filarial Nematode Parasite Brugia Malayi, Elodie Ghedin, Shiliang Wang, David Spiro, Elisabet Caler, Qi Zhao, Jonathan Crabtree, Jonathan E. Allen, Arthur L. Delcher, David B. Guiliano, Diego Miranda-Saavedra, Samuel V. Angiuoli, Todd Creasy, Paolo Amedeo, Brian Haas, Najib M. El-Sayed, Jennifer R. Wortman, Tamara Feldblyum, Luke Tallon, Michael Schatz, Martin Shumway, Hean Koo, Steven L. Salzberg, Seth Schobel, Mihaela Pertea, Mihai Pop, Owen White, Geoffrey J. Barton, Clotilde K.S. Carlow, Michael J. Crawford, Jennifer Daub, Et Al, Steven A. Williams

Biological Sciences: Faculty Publications

Parasitic nematodes that cause elephantiasis and river blindness threaten hundreds of millions of people in the developing world. We have sequenced the ∼90 megabase (Mb) genome of the human filarial parasite Brugia malayi and predict ∼11,500 protein coding genes in 71 Mb of robustly assembled sequence. Comparative analysis with the free-living, model nematode Caenorhabditis elegans revealed that, despite these genes having maintained little conservation of local synteny during ∼350 million years of evolution, they largely remain in linkage on chromosomal units. More than 100 conserved operons were identified. Analysis of the predicted proteome provides evidence for adaptations of B. malayi …

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Human Body Temperature (37°C) Increases The Expression Of Iron, Carbohydrate, And Amino Acid Utilization Genes In Escherichia Coli K-12, Christine A. White-Ziegler, Amy J. Malhowski, Sarah Young Aug 2007

Human Body Temperature (37°C) Increases The Expression Of Iron, Carbohydrate, And Amino Acid Utilization Genes In Escherichia Coli K-12, Christine A. White-Ziegler, Amy J. Malhowski, Sarah Young

Biological Sciences: Faculty Publications

Using DNA microarrays, we identified 126 genes in Escherichia coli K-12 whose expression is increased at human body temperature (37°C) compared to growth at 23°C. Genes involved in the uptake and utilization of amino acids, carbohydrates, and iron dominated the list, supporting a model in which temperature serves as a host cue to increase expression of bacterial genes needed for growth. Using quantitative real-time PCR, we investigated the thermoregulatory response for representative genes in each of these three categories (hisJ, cysP, srlE, garP, fes, and cirA), along with the fimbrial gene papB. Increased expression at 37°C compared to 23°C was …

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Spatial Variation In Sea Urchins, Fish Predators, And Bioerosion Rates On Coral Reefs Of Belize, Jocelyn Brown-Saracino, Paulette Peckol, H. Allen Curran, Martha L. Robbart Mar 2007

Spatial Variation In Sea Urchins, Fish Predators, And Bioerosion Rates On Coral Reefs Of Belize, Jocelyn Brown-Saracino, Paulette Peckol, H. Allen Curran, Martha L. Robbart

Biological Sciences: Faculty Publications

Although sea urchins are critical for controlling macroalgae on heavily fished coral reefs, high densities threaten reefs, as urchins are also prodigous bioeroders. This study examined urchin population characteristics, bioerosion rates, their fish predators (Labridae), and potential competitors (Scaridae) on unprotected reefs and a reef within a marine protected area (MPA) in the lagoonal regions off Belize. Urchin density (<1 >m-2) and bioerosion rates (∼0.2 kg CaCO3m-2year-1) were lowest and members of the Labridae were the highest (∼20 fish 200 m-3) within the MPA, while several unprotected reefs had higher (∼18-40 m-2) urchin densities, lower Labridae abundances (1-3 fish 200 …

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Notch Signaling Controls The Differentiation Of Transporting Epithelia And Multiciliated Cells In The Zebrafish Pronephros, Yan Liu, Narendra Pathak, Albrecht Kramer-Zucker, Iain A. Drummond Mar 2007

Notch Signaling Controls The Differentiation Of Transporting Epithelia And Multiciliated Cells In The Zebrafish Pronephros, Yan Liu, Narendra Pathak, Albrecht Kramer-Zucker, Iain A. Drummond

Neuroscience: Faculty Publications

Epithelial tubules consist of multiple cell types that are specialized for specific aspects of organ function. In the zebrafish pronephros, multiciliated cells (MCCs) are specialized for fluid propulsion, whereas transporting epithelial cells recover filtered-blood solutes. These cell types are distributed in a 'salt-and-pepper' fashion in the pronephros, suggesting that a lateral inhibition mechanism may play a role in their differentiation. We find that the Notch ligand Jagged 2 is expressed in MCCs and that notch3 is expressed in pronephric epithelial cells. Morpholino knockdown of either jagged 2 or notch3, or mutation in mind bomb (in which Notch signaling is impaired), …

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Hiring Criteria In Biology Departments Of Academic Institutions, Christine M. Fleet, Meredith F.N. Rosser, Rebecca A. Zufall, Marney C. Pratt, Tracy S. Feldman, Paula P. Lemons May 2006

Hiring Criteria In Biology Departments Of Academic Institutions, Christine M. Fleet, Meredith F.N. Rosser, Rebecca A. Zufall, Marney C. Pratt, Tracy S. Feldman, Paula P. Lemons

Biological Sciences: Faculty Publications

We surveyed faculty in the biology departments of US institutions of higher education to compare the experience and training valued by faculty at hiring institutions with the experience and training most graduate students receive. Our data show that associate, baccalaureate, and master's institutions value teaching experience and skills more highly than research skills. In contrast, doctoral institutions place a higher value on the ability to publish research and obtain outside funding. These findings provide quantitative and qualitative insight into discrepancies between the values of those who train graduate students in biology and the expectations of the institutions likely to hire …

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A Real-Time Pcr-Based Assay For Detection Of Wuchereria Bancrofti Dna In Blood And Mosquitoes, Ramakrishna U. Rao, Laura J. Atkinson, Reda M.R. Ramzy, Hanan H. Helmy, Hoda A. Farid, Moses J. Bockarie, Melinda Susapu, Sandra J. Laney, Steven A. Williams, Gary J. Weil Jan 2006

A Real-Time Pcr-Based Assay For Detection Of Wuchereria Bancrofti Dna In Blood And Mosquitoes, Ramakrishna U. Rao, Laura J. Atkinson, Reda M.R. Ramzy, Hanan H. Helmy, Hoda A. Farid, Moses J. Bockarie, Melinda Susapu, Sandra J. Laney, Steven A. Williams, Gary J. Weil

Biological Sciences: Faculty Publications

We developed and evaluated real-time polymerase chain reaction (PCR) assays for detecting Wuchereria bancrofti DNA in human blood and in mosquitoes. An assay based on detection of the W. bancrofti “LDR” repeat DNA sequence was more sensitive than an assay for Wolbachia 16S rDNA. The LDR-based assay was sensitive for detecting microfilarial DNA on dried membrane filters or on filter paper. We also compared real-time PCR with conventional PCR (C-PCR) for detecting W. bancrofti DNA in mosquito samples collected in endemic areas in Egypt and Papua New Guinea. Although the two methods had comparable sensitivity for detecting filarial DNA in …

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Generality Of Vertebrate Developmental Patterns: Evidence For A Dermomyotome In Fish, S. H. Devoto, W. Stoiber, C. L. Hammond, P. Steinbacher, J. R. Haslett, M. J.F. Barresi, S. E. Patterson, E. G. Adiarte, S. M. Hughes Jan 2006

Generality Of Vertebrate Developmental Patterns: Evidence For A Dermomyotome In Fish, S. H. Devoto, W. Stoiber, C. L. Hammond, P. Steinbacher, J. R. Haslett, M. J.F. Barresi, S. E. Patterson, E. G. Adiarte, S. M. Hughes

Biological Sciences: Faculty Publications

The somitic compartment that gives rise to trunk muscle and dermis in amniotes is an epithelial sheet on the external surface of the somite, and is known as the dermomyotome. However, despite its central role in the development of the trunk and limbs, the evolutionary history of the dermomyotome and its role in nonamniotes is poorly understood. We have tested whether a tissue with the morphological and molecular characteristics of a dermomyotome exists in nonamniotes. We show that representatives of the agnathans and of all major clades of gnathostomes each have a layer of cells on the surface of the …

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Coral Reef Ed-Ventures: An Environmental Education Program For School Children In San Pedro, Belize, H. Allen Curran, Susan Etheredge, Elizabeth Callaghan, Paulette M. Peckol Oct 2005

Coral Reef Ed-Ventures: An Environmental Education Program For School Children In San Pedro, Belize, H. Allen Curran, Susan Etheredge, Elizabeth Callaghan, Paulette M. Peckol

Geosciences: Faculty Publications

No abstract provided.

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Characterization Of A Novel Filarial Serine Protease Inhibitor, Ov-Spi-1, From Onchocerca Volvulus, With Potential Multifunctional Roles During Development Of The Parasite, Louise Ford, David B. Guiliano, Yelena Oksov, Asim K. Debnath, Jing Liu, Steven A. Williams, Mark L. Blaxter, Sara Lustigman Sep 2005

Characterization Of A Novel Filarial Serine Protease Inhibitor, Ov-Spi-1, From Onchocerca Volvulus, With Potential Multifunctional Roles During Development Of The Parasite, Louise Ford, David B. Guiliano, Yelena Oksov, Asim K. Debnath, Jing Liu, Steven A. Williams, Mark L. Blaxter, Sara Lustigman

Biological Sciences: Faculty Publications

A novel filarial serine protease inhibitor (SPI) from the human parasitic nematode Onchocerca volvulus, Ov-SPI-1, was identified through the analysis of a molting third-stage larvae expressed sequence tag dataset. Subsequent analysis of the expressed sequence tag datasets of O. volvulus and other filariae identified four other members of this family. These proteins are related to the low molecular weight SPIs originally isolated from Ascaris suumwhere they are believed to protect the parasite from host intestinal proteases. The two Ov-spi transcripts are up-regulated in the molt- ing larvae and adult stages of the development of the parasite. Recombinant Ov-SPI-1 is an …

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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 Aug 2005

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, …

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Increased Action Potential Firing Rates Of Layer 2/3 Pyramidal Cells In The Prefrontal Cortex Are Significantly Related To Cognitive Performance In Aged Monkeys, Yu Ming Chang, Douglas L. Rosene, Ronald J. Killiany, Lisa A. Mangiamele, Jennifer I. Luebke Apr 2005

Increased Action Potential Firing Rates Of Layer 2/3 Pyramidal Cells In The Prefrontal Cortex Are Significantly Related To Cognitive Performance In Aged Monkeys, Yu Ming Chang, Douglas L. Rosene, Ronald J. Killiany, Lisa A. Mangiamele, Jennifer I. Luebke

Biological Sciences: Faculty Publications

The neurobiological substrates of significant age-related deficits in higher cognitive abilities mediated by the prefrontal cortex (PFC) are unknown. To address this issue, whole-cell current-clamp recordings were used to compare the intrinsic membrane and action potential (AP) firing properties of layer 2/3 pyramidal cells in PFC slices from young and aged behaviorally characterized rhesus monkeys. Most aged subjects demonstrated impaired performance in Delayed Non-Match to Sample (DNMS) task acquisition, DNMS 2 min delay and the Delayed Recognition Span task. Resting membrane potential and membrane time constant did not differ in aged relative to young cells, but input resistance was significantly …

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Rich Mesic Forests: Edaphic And Physiographic Drivers Of Community Variation In Western Massachusetts, J. Bellemare, G. Motzkin, D. R. Foster Jan 2005

Rich Mesic Forests: Edaphic And Physiographic Drivers Of Community Variation In Western Massachusetts, J. Bellemare, G. Motzkin, D. R. Foster

Biological Sciences: Faculty Publications

Rich Mesic Forest, a Northeastern variant of the species-rich Mixed Mesophytic Forest association of eastern North America, is an Acer saccharum-dominated forest type typically associated with calcareous bedrock and nutrient-rich, mull soils. Rich Mesic Forest (RMF) is a priority for conservation in the Northeast due to its limited areal extent, high plant species richness, and numerous rare taxa, yet the community characteristics and environmental correlates of this forest type are incompletely understood. This study undertook a quantitative classification of RMF of the northeastern edge of the Berkshire Plateau in western Massachusetts. Cluster analysis of data from ten sites identified two …

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Filarial Genomics, Steven A. Williams Nov 2004

Filarial Genomics, Steven A. Williams

Biological Sciences: Faculty Publications

No abstract provided.

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Effect Of Zooid Spacing On Bryozoan Feeding Success: Is Competition Or Facilitation More Important?, Marney C. Pratt Jan 2004

Effect Of Zooid Spacing On Bryozoan Feeding Success: Is Competition Or Facilitation More Important?, Marney C. Pratt

Biological Sciences: Faculty Publications

Most Recent bryozoan species are encrusting sheets, and many of these colonies have densely packed feeding zooids. In this study, I tested whether tight packing of feeding zooids affects food capture. Colonies of a bryozoan with an encrusting sheet form (Membranipora membranacea) were dissected to produce individuals whose feeding zooids were (1) closely packed, (2) more widely spaced, or (3) isolated. For each type, rates of particle ingestion were measured in still water and in a freestream velocity of 2.7 cm s-1. Ingestion rate increased when zooids were closest together, probably because of reduced refiltration and increased feeding current strength …

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Shallow-Water Coral Reefs In Transition: Examples From Belize And The Bahamas, H. Allen Curran, Paulette M. Peckol, Benjamin J. Greenstein, Shannon Ristau, Susan Deyoung Jan 2004

Shallow-Water Coral Reefs In Transition: Examples From Belize And The Bahamas, H. Allen Curran, Paulette M. Peckol, Benjamin J. Greenstein, Shannon Ristau, Susan Deyoung

Geosciences: Faculty Publications

Reprinted from: Ronald D. Lewis and Bruce C. Panuska (eds.) Proceedings of the 11th Symposium on the Geology of the Bahamas and Other Carbonate Regions: San Salvador, Gerace Research Center

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Multiple Roles For Hedgehog Signaling In Zebrafish Pituitary Development, Jennifer L. Sbrogna, Michael J.F. Barresi, Rolf O. Karlstrom Feb 2003

Multiple Roles For Hedgehog Signaling In Zebrafish Pituitary Development, Jennifer L. Sbrogna, Michael J.F. Barresi, Rolf O. Karlstrom

Biological Sciences: Faculty Publications

The endocrine-secreting lobe of the pituitary gland, or adenohypophysis, forms from cells at the anterior margin of the neural plate through inductive interactions involving secreted morphogens of the Hedgehog (Hh), fibroblast growth factor (FGF), and bone morphogenetic protein (BMP) families. To better understand when and where Hh signaling influences pituitary development, we have analyzed the effects of blocking Hh signaling both pharmacologically (cyclopamine treatments) and genetically (zebrafish Hh pathway mutants). While current models state that Shh signaling from the oral ectoderm patterns the pituitary after placode induction, our data suggest that Shh plays a direct early role in both pituitary …

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The N-Acetyltransferase Rimj Responds To Environmental Stimuli To Repress Pap Fimbrial Transcription In Escherichia Coli, Christine A. White-Ziegler, Alia M. Black, Stacie H. Eliades, Sarah Young, Kimberly Porter Aug 2002

The N-Acetyltransferase Rimj Responds To Environmental Stimuli To Repress Pap Fimbrial Transcription In Escherichia Coli, Christine A. White-Ziegler, Alia M. Black, Stacie H. Eliades, Sarah Young, Kimberly Porter

Biological Sciences: Faculty Publications

In uropathogenic Escherichia coli, P pili (Pap) facilitate binding to host epithelial cells and subsequent colonization. Whereas P pili can be produced at 37°C, the expression of these fimbriae is suppressed at 23°C. Previously, insertion mutations in rimJ, a gene encoding the N-terminal acetyltransferase of ribosomal protein S5, were shown to disrupt this thermoregulatory response, allowing papBA transcription at low temperature. In this study, we created an in-frame deletion of rimJ. This deletion relieved the repressive effects not only of low temperature but also of rich (Luria-Bertani [LB]) medium and glucose on papBA transcription, indicating that RimJ modulates papBA transcription …

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Strength, Drag, And Dislodgment Of Two Competing Intertidal Algae From Two Wave Exposures And Four Seasons, Marney C. Pratt, Amy S. Johnson Jun 2002

Strength, Drag, And Dislodgment Of Two Competing Intertidal Algae From Two Wave Exposures And Four Seasons, Marney C. Pratt, Amy S. Johnson

Biological Sciences: Faculty Publications

Intertidal macroalgae often experience greater risk of dislodgment with increasing size because of underscaling of breaking force of their stipes relative to drag on their thalli. This ratio (breaking force/drag) indicates safety from breakage at a given flow speed, with values greater than one indicating safety from breakage and values lower than one indicating danger of breakage. We examined this force ratio for the largest thalli of two species of co-dominant, red algae, Chondrus crispus Stackhouse and Mastocarpus stellatus Stack. In With. (Guiry), in four seasons at two wave exposures. During fall and winter, the largest thalli in both populations …

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Functional Morphology And Developmental Biology Of Zebrafish: Reciprocal Illumination From An Unlikely Couple, L. Patricia Hernández, Michael J.F. Barresi, Stephen H. Devoto Jan 2002

Functional Morphology And Developmental Biology Of Zebrafish: Reciprocal Illumination From An Unlikely Couple, L. Patricia Hernández, Michael J.F. Barresi, Stephen H. Devoto

Biological Sciences: Faculty Publications

Functional morphology has benefited greatly from the input of techniques and thinking from other disciplines. This has been especially productive in situations where each discipline has made significant contributions to a particular research topic. A combination of methodologies from functional morphology and developmental biology has allowed us to characterize feeding mechanics of first-feeding larval zebrafish (Danio rerio). Contrary to kinematic patterns commonly seen in adult teleosts, larval zebrafish showed no lateral abduction during the expansive phase of a suction-feeding event. Instead, dorsoventral expansion of the buccal chamber, more typical of patterns seen in primitive fishes, characterized the expansive phase. Moreover, …

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Distinct Mechanisms Regulate Slow-Muscle Development, Michael J.F. Barresi, Joel A. D'Angelo, L. Patricia Hernández, Stephen H. Devoto Sep 2001

Distinct Mechanisms Regulate Slow-Muscle Development, Michael J.F. Barresi, Joel A. D'Angelo, L. Patricia Hernández, Stephen H. Devoto

Biological Sciences: Faculty Publications

Vertebrate muscle development begins with the patterning of the paraxial mesoderm by inductive signals from midline tissues [1, 2]. Subsequent myotome growth occurs by the addition of new muscle fibers. We show that in zebrafish new slow-muscle fibers are first added at the end of the segmentation period in growth zones near the dorsal and ventral extremes of the myotome, and this muscle growth continues into larval life. In marine teleosts, this mechanism of growth has been termed stratified hyperplasia [3]. We have tested whether these added fibers require an embryonic architecture of muscle fibers to support their development and …

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Somite Development In Zebrafish, Heather L. Stickney, Michael J.F. Barresi, Stephen H. Devoto Nov 2000

Somite Development In Zebrafish, Heather L. Stickney, Michael J.F. Barresi, Stephen H. Devoto

Biological Sciences: Faculty Publications

A full understanding of somite development requires knowledge of the molecular genetic pathways for cell determination as well as the cellular behaviors that underlie segmentation, somite epithelialization, and somite patterning. The zebrafish has long been recognized as an ideal organism for cellular and histological studies of somite patterning. In recent years, genetics has proven to be a very powerful complementary approach to these embryological studies, as genetic screens for zebrafish mutants defective in somitogenesis have identified over 50 genes that are necessary for normal somite development. Zebrafish is thus an ideal system in which to analyze the role of specific …

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H-Ns Controls Pap And Daa Fimbrial Transcription In Escherichia Coli In Response To Multiple Environmental Cues, C. A. White-Ziegler, A. Villapakkam, K. Ronaszeki, S. Young Nov 2000

H-Ns Controls Pap And Daa Fimbrial Transcription In Escherichia Coli In Response To Multiple Environmental Cues, C. A. White-Ziegler, A. Villapakkam, K. Ronaszeki, S. Young

Biological Sciences: Faculty Publications

A comparative study was completed to determine the influence of various environmental stimuli on the transcription of three different fimbrial operons in Escherichia coli and to determine the role of the histone-like protein H-NS in this environmental regulation. The fimbrial operons studied included the pap operon, which encodes pyelonephritis-associated pili (P pili), the daa operon, which encodes F1845 fimbriae, and the fan operon, which encodes K99 fimbriae. Using lacZYA transcriptional fusions within each of the fimbrial operons, we tested temperature, osmolarity, carbon source, rich medium, oxygen levels, pH, amino acids, solid medium, and iron concentration for their effects on fimbrial …

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