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2004

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Articles 61 - 90 of 418

Full-Text Articles in Biology

Evidence That Thyroid Hormone Induces Olfactory Cellular Proliferation In Salmon During A Sensitive Period For Imprinting, Sean C. Lema, Gabrielle A. Nevitt Oct 2004

Evidence That Thyroid Hormone Induces Olfactory Cellular Proliferation In Salmon During A Sensitive Period For Imprinting, Sean C. Lema, Gabrielle A. Nevitt

Biological Sciences

Salmon have long been known to imprint and home to natal stream odors, yet the mechanisms driving olfactory imprinting remain obscure. The timing of imprinting is associated with elevations in plasma thyroid hormone levels, with possible effects on growth and proliferation of the peripheral olfactory system. Here, we begin to test this idea by determining whether experimentally elevated plasma levels of 3,5,3′-triiodothyronine (T3) influence cell proliferation as detected by the 5-bromo-2′-deoxyuridine (BrdU) cell birth-dating technique in the olfactory epithelium of juvenile coho salmon (Oncorhynchus kisutch). We also explore how natural fluctuations in thyroxine (T4) …


Renesting Decisions And Annual Fecundity Of Female Dickcissels (Spiza Americana) In Illinois, Jeffrey W. Walk, Kevin Wentworth, Eric L. Kershner, Eric K. Bollinger, Richard E. Warner Oct 2004

Renesting Decisions And Annual Fecundity Of Female Dickcissels (Spiza Americana) In Illinois, Jeffrey W. Walk, Kevin Wentworth, Eric L. Kershner, Eric K. Bollinger, Richard E. Warner

Faculty Research & Creative Activity

ABSTRACT.-Renesting decisions and annual fecundity are crucial for interpreting other demographic information, yet are infrequently reported. We used radiotelemetry to monitor female Dickcissels (Spiza americana) throughout the 1999 and 2000 breeding seasons in southeastern Illinois. Overall fecundity (regardless of whether females remained in the study area throughout the breeding season) was 0.61 ± 0.13 female fledglings per year. Of females that remained within the study area, 94% fledged young (1.25 ± 0.15 female fledglings per year). Most females (62%) that experienced nest failure emigrated from the study area (moved >10 km) in 2.8 ± 0.6 days; others (36%) initiated subsequent …


Renesting Decisions And Annual Fecundity Of Female Dickcissels (Spiza Americana) In Illinois, Jeffrey Walk, Kevin Wentworth, Eric Kershner, Eric Bollinger, Richard Warner Oct 2004

Renesting Decisions And Annual Fecundity Of Female Dickcissels (Spiza Americana) In Illinois, Jeffrey Walk, Kevin Wentworth, Eric Kershner, Eric Bollinger, Richard Warner

Faculty Research & Creative Activity

ABSTRACT.-Renesting decisions and annual fecundity are crucial for interpreting other demographic information, yet are infrequently reported. We used radiotelemetry to monitor female Dickcissels (Spiza americana) throughout the 1999 and 2000 breeding seasons in southeastern Illinois. Overall fecundity (regardless of whether females remained in the study area throughout the breeding season) was 0.61 ± 0.13 female fledglings per year. Of females that remained within the study area, 94% fledged young (1.25 ± 0.15 female fledglings per year). Most females (62%) that experienced nest failure emigrated from the study area (moved >10 km) in 2.8 ± 0.6 days; others (36%) initiated subsequent …


Germination Of Silene Regia Seeds From Four Sites In Lawrence County, Illinois, Following Scarification Or Stratification, Nicolette Flocca, Janice Coons, Henry Owen, Brian Fischer, Bob Edgin Oct 2004

Germination Of Silene Regia Seeds From Four Sites In Lawrence County, Illinois, Following Scarification Or Stratification, Nicolette Flocca, Janice Coons, Henry Owen, Brian Fischer, Bob Edgin

Faculty Research & Creative Activity

Silene regia Sims is an endangered prairie forb in Illinois where small isolated colonies are scattered. In La·wrence County, two sites (Allison Prairie and Chauncey Marsh) have fewer plants (6-23) than two other sites (Cmmty Road and Cemetery) with 26-45 plants. Information on seed germination in these isolated colonies is needed. Our goal was to evaluate seed germination of S. regia from colonies in Lawrence County, illinois. S. regia fruits were collected from these four sites on August 9 and 19, 1999. Seeds were scarified by cutting the seed coat, or they were stratified at 2 C for 12 or …


Complete Genomic Sequence Of Bacteriophage B3, A Mu-Like Phage Of Pseudomonas Aeruginosa, Michael D. Braid, Jennifer L. Silhavy, Christopher L. Kitts, Raul J. Cano, Martha M. Howe Oct 2004

Complete Genomic Sequence Of Bacteriophage B3, A Mu-Like Phage Of Pseudomonas Aeruginosa, Michael D. Braid, Jennifer L. Silhavy, Christopher L. Kitts, Raul J. Cano, Martha M. Howe

Biological Sciences

Bacteriophage B3 is a transposable phage of Pseudomonas aeruginosa. In this report, we present the complete DNA sequence and annotation of the B3 genome. DNA sequence analysis revealed that the B3 genome is 38,439 bp long with a G+C content of 63.3%. The genome contains 59 proposed open reading frames (ORFs) organized into at least three operons. Of these ORFs, the predicted proteins from 41 ORFs (68%) display significant similarity to other phage or bacterial proteins. Many of the predicted B3 proteins are homologous to those encoded by the early genes and head genes of Mu and Mu-like prophages found …


Facultative Altitudinal Movements By Mountain White-Crowned Sparrows (Zonotrichia Leucophrys Oriantha) In The Sierra Nevada, Thomas P. Hahn, Keith W. Sockman, Creagh W. Breuner, Martin L. Morton Oct 2004

Facultative Altitudinal Movements By Mountain White-Crowned Sparrows (Zonotrichia Leucophrys Oriantha) In The Sierra Nevada, Thomas P. Hahn, Keith W. Sockman, Creagh W. Breuner, Martin L. Morton

Biological Sciences Faculty Publications

Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) winter in Mexico and often arrive in the vicinity of their breeding grounds in the Sierra Nevada well before nesting is possible. Arrival at Tioga Pass, Califomia (elevation 3,030 m), usually occurs in early May, but residual winter snow and adverse weather can delay nesting for weeks. We used radiotelemetry to determine whether prebreeding Mountain White-crowned Sparrows engaged in weather-related altitudinal movements during the waiting period between the end of spring migration and onset of breeding during 1995-2001, with a range of residual winter snowpacks. Interannual variation in arrival date and onset …


The Signal Peptide Of The Junín Arenavirus Envelope Glycoprotein Is Myristoylated And Forms An Essential Subunit Of The Mature G1-G2 Complex, Joanne York, Victor Romanowski, Min Lu, Jack H. Nunberg Oct 2004

The Signal Peptide Of The Junín Arenavirus Envelope Glycoprotein Is Myristoylated And Forms An Essential Subunit Of The Mature G1-G2 Complex, Joanne York, Victor Romanowski, Min Lu, Jack H. Nunberg

Biological Sciences Faculty Publications

Arenaviruses comprise a diverse family of rodent-borne viruses that are responsible for recurring and emerging outbreaks of viral hemorrhagic fevers worldwide. The Junin virus, a member of the New World arenaviruses, is endemic to the pampas grasslands of Argentina and is the etiologic agent of Argentine hemorrhagic fever. In this study, we have analyzed the assembly and function of the Junin virus envelope glycoproteins. The mature envelope glycoprotein complex is proteolytically processed from the GP-C precursor polypeptide and consists of three noncovalently associated subunits, G1, G2, and a stable 58-amino-acid signal peptide. This tripartite organization is found both on virions …


Nest-Building And Spawning Behaviors In Nocomis Effusus (Actinopterygii: Cyprindae), Eugene G. Maurakis, George E. Maurakis Oct 2004

Nest-Building And Spawning Behaviors In Nocomis Effusus (Actinopterygii: Cyprindae), Eugene G. Maurakis, George E. Maurakis

Virginia Journal of Science

Spawning behavior in Nocomis effusus is described from direct observations and review of videotapes made in Yellow Creek (Cumberland River drainage), Tennessee in 2003. Nest construction (i.e., excavating a concavity, forming a platform, and building a mound), and spawning behavior in N. effusus where a single breeding male excavates a pit and spawns with females on the upstream slope of his nest is like that described for Nocomis asper and Nocomis biguttatus. In digging a spawning pit, a male N. effusus reshapes and reorganizes substrate materials that results in spawning areas on the upstream slope of the nest composed …


Growth Of Stygobitic (Orconectes Australis Packardi) And Epigean (Orconectes Cristavarius) Crayfishes Maintained In Laboratory Conditions, Ann-Simone Cooper, Robin L. Cooper Oct 2004

Growth Of Stygobitic (Orconectes Australis Packardi) And Epigean (Orconectes Cristavarius) Crayfishes Maintained In Laboratory Conditions, Ann-Simone Cooper, Robin L. Cooper

Biology Faculty Publications

This study reports on maintenance and growth of the cave crayfish, Orconectes australis packardi, and the epigean crayfish, Orconectes cristavarius, with laboratory conditions for 1 and 2 years. The O. a. packardi survived well compared to the O. cristavarius in captivity. The poor survival of the epigean species was probably due to unsuitable conditions. The epigean as well as the cave crayfish molted and grew in captivity, but without any significant difference in molt frequency between species. In the first year, total body length was obtained to assay growth, whereas in the second year the more accurate measure …


Review: 'A Spirituality Of Dating, Love, Dinner, And The Divine', William P. Roberts Oct 2004

Review: 'A Spirituality Of Dating, Love, Dinner, And The Divine', William P. Roberts

Theology and Religious Studies Faculty Publications

No abstract provided.


Novel Weapons: Invasive Success And The Evolution Of Increased Competitive Ability, Ragan M. Callaway, Wendy M. Ridenour Oct 2004

Novel Weapons: Invasive Success And The Evolution Of Increased Competitive Ability, Ragan M. Callaway, Wendy M. Ridenour

Biological Sciences Faculty Publications

When introduced to new habitats by humans, some plant species become much more dominant. This is primarily attributed to escape from specialist consumers. Release from these specialist enemies is also thought by some to lead to the evolution of increased competitive ability, driven by a decrease in the plant's resource allocation to consumer defense and an increase in allocation to size or fecundity. Here, we discuss a new theory for invasive success – the “novel weapons hypothesis”. We propose that some invaders transform because they possess novel biochemical weapons that function as unusually powerful allelopathic agents, or as mediators of …


Asymmetric Atp Binding And Hydrolysis Activity Of The Thermus Aquaticus Muts Dimer Is Key To Modulation Of Its Interactions With Mismatched Dna, Edwin Antony, Manju M. Hingorani Oct 2004

Asymmetric Atp Binding And Hydrolysis Activity Of The Thermus Aquaticus Muts Dimer Is Key To Modulation Of Its Interactions With Mismatched Dna, Edwin Antony, Manju M. Hingorani

Biological Sciences Faculty Research and Publications

Prokaryotic MutS and eukaryotic Msh proteins recognize base pair mismatches and insertions or deletions in DNA and initiate mismatch repair. These proteins function as dimers (and perhaps higher order oligomers) and possess an ATPase activity that is essential for DNA repair. Previous studies of Escherichia coli MutS and eukaryotic Msh2−Msh6 proteins have revealed asymmetry within the dimer with respect to both DNA binding and ATPase activities. We have found the Thermus aquaticus MutS protein amenable to detailed investigation of the nature and role of this asymmetry. Here, we show that (a) in a MutS dimer one subunit (S1) binds nucleotide …


Improved Phase Modulation For An En-Face Scanning Three-Dimensional Optical Coherence Microscope, Barbara M. Hoeling, Mary E. Peter, Daniel C. Petersen, Richard C. Haskell Sep 2004

Improved Phase Modulation For An En-Face Scanning Three-Dimensional Optical Coherence Microscope, Barbara M. Hoeling, Mary E. Peter, Daniel C. Petersen, Richard C. Haskell

All HMC Faculty Publications and Research

We have previously described an inexpensive method for modulating the interferometer of an en-face scanning, focus-tracking, three-dimensional optical coherence microscope (OCM). In this OCM design, a reference mirror is mounted on a piezoelectric stack driven at a resonance frequency of about 100 kHz. We perform a partial discrete Fourier transform of the digitally sampled output fringe signal. In the original design, we obtained the amplitude of the backscattered light by summing the powers in the fundamental (1ω) and first harmonic (2ω) of the modulation frequency. We used the particular piezoamplitude that eliminates the effects of interferometer phase drift. However, as …


Biology Department Publications: 2004, Sam Lindgren Sep 2004

Biology Department Publications: 2004, Sam Lindgren

Biology Department Bibliographies

This document is a noncomprehensive list of publications made by graduate students, post-doctoral researchers, and faculty members in the Biology Department in 2004. It indexes those publications available through major databases, and serves as an archival record of the Department’s robust scholarly contributions.


Human Stick Balancing: Tuning Lèvy Flights To Improve Balance Control, Juan Luis Cabrera, John Milton Sep 2004

Human Stick Balancing: Tuning Lèvy Flights To Improve Balance Control, Juan Luis Cabrera, John Milton

WM Keck Science Faculty Papers

State-dependent, or parametric, noise is an essential component of the neural control mechanism for stick balancing at the fingertip. High-speed motion analysis in three dimensions demonstrates that the controlling movements made by the fingertip during stick balancing can be described by a Lévy flight. The Lévy index, , is approximately 0.9; a value close to optimal for a random search. With increased skill, the index does not change. However, the tails of the Lévy distribution become broader. These observations suggest a Lévy flight that is truncated by the properties of the nervous and musculoskeletal system; the truncation decreasing as skill …


Identification And Inactivation Of Genetic Loci Involved With Lactobacillus Acidophilus Acid Tolerance, M. Andrea Azcarate-Peril, Eric Altermann, Rebecca L. Hoover- Fitzula, Raul J. Cano, Todd R. Klaenhammer Sep 2004

Identification And Inactivation Of Genetic Loci Involved With Lactobacillus Acidophilus Acid Tolerance, M. Andrea Azcarate-Peril, Eric Altermann, Rebecca L. Hoover- Fitzula, Raul J. Cano, Todd R. Klaenhammer

Biological Sciences

Amino acid decarboxylation-antiporter reactions are one of themost important systems for maintaining intracellular pH betweenphysiological limits under acid stress. We analyzed the Lactobacillusacidophilus NCFM complete genome sequence and selected fouropen reading frames with similarities to genes involved withdecarboxylation reactions involved in acid tolerance in severalmicroorganisms. Putative genes encoding an ornithine decarboxylase,an amino acid permease, a glutamate -aminobutyrate antiporter,and a transcriptional regulator were disrupted by insertionalinactivation. The ability of L. acidophilus to survive low-pHconditions, such as those encountered in the stomach or fermenteddairy foods, was investigated and compared to the abilitiesof early- and late-stationary-phase cells of the mutants bychallenging them with …


Visualizing Early Frog Development With Motion-Sensitive 3-D Optical Coherence Microscopy, Richard C. Haskell, Mary E. Williams, Daniel C. Petersen, Barbara M. Hoeling, Andrew J. Schile, J. D. Pennington, M. G. Seetin, J. M. Castelaz, Scott E. Fraser, Cyrus Papan, Hongwu Ren, Johannes F. De Boer, Zhongping Chen Sep 2004

Visualizing Early Frog Development With Motion-Sensitive 3-D Optical Coherence Microscopy, Richard C. Haskell, Mary E. Williams, Daniel C. Petersen, Barbara M. Hoeling, Andrew J. Schile, J. D. Pennington, M. G. Seetin, J. M. Castelaz, Scott E. Fraser, Cyrus Papan, Hongwu Ren, Johannes F. De Boer, Zhongping Chen

All HMC Faculty Publications and Research

A motion-sensitive en-face-scanning 3-D optical coherence microscope (OCM) has been designed and constructed to study critical events in the early development of plants and animals. We describe the OCM instrument and present time-lapse movies of frog gastrulation, an early developmental event in which three distinct tissue layers are established that later give rise to all major organ systems. OCM images constructed with fringe-amplitude data show the mesendoderm migrating up along the blastocoel roof, thus forming the inner two tissue layers. Motion-sigma data, measuring the random motion of scatterers, is used to construct complementary images that indicate the presence of Brownian …


Immunogold Labeling To Enhance Contrast In Optical Coherence Microscopy Of Tissue Engineered Corneal Constructs, Chris B. Raub, Elizabeth J. Orwin, Richard C. Haskell Sep 2004

Immunogold Labeling To Enhance Contrast In Optical Coherence Microscopy Of Tissue Engineered Corneal Constructs, Chris B. Raub, Elizabeth J. Orwin, Richard C. Haskell

All HMC Faculty Publications and Research

Our lab has used an optical coherence microscope (OCM) to assess both the structure of tissue-engineered corneal constructs and their transparency. Currently, we are not able to resolve cells versus collagen matrix material in the images produced. We would like to distinguish cells in order to determine if they are viable while growing in culture and also if they are significantly contributing to the light scattering in the tissue. In order to do this, we are currently investigating the use of immunogold labeling. Gold nanoparticles are high scatterers and can create contrast in images. We have conjugated gold nanoparticles to …


Testing Species Boundaries In An Ancient Species Complex With Deep Phylogeographic History: Genus Xantusia (Squamata: Xantusiidae), Keith A. Crandall, Elizabeth A. Sinclair, Robert L. Bezy, Kathryn Bolles, Jose L. Camarillo, Jack W. Sites Sep 2004

Testing Species Boundaries In An Ancient Species Complex With Deep Phylogeographic History: Genus Xantusia (Squamata: Xantusiidae), Keith A. Crandall, Elizabeth A. Sinclair, Robert L. Bezy, Kathryn Bolles, Jose L. Camarillo, Jack W. Sites

Faculty Publications

Identification of species in natural populations has recently received increased attention with a number of investigators proposing rigorous methods for species delimitation. Morphologically conservative species (or species complexes) with deep phylogenetic histories (and limited gene flow) are likely to pose particular problems when attempting to delimit species, yet this is crucial to comparative studies of the geography of speciation. We apply two methods of species delimitation to an ancient group of lizards (genus Xantusia) that occur throughout southwestern North America. Mitochondrial cytochrome b and nicotinamide adenine dinucleotide dehydrogenase subunit 4 gene sequences were generated from samples taken throughout the geographic …


The Bvg Virulence Control System Regulates Biofilm Formation In Bordetella Bronchiseptica, Yasuhiko Irie, Seema Mattoo, Ming H. Yuk Sep 2004

The Bvg Virulence Control System Regulates Biofilm Formation In Bordetella Bronchiseptica, Yasuhiko Irie, Seema Mattoo, Ming H. Yuk

Biology Faculty Publications

Bordetella species utilize the BvgAS (Bordetella virulence gene) two-component signal transduction system to sense the environment and regulate gene expression among at least three phases: a virulent Bvg+ phase, a nonvirulent Bvg− phase, and an intermediate Bvgi phase. Genes expressed in the Bvg+ phase encode known virulence factors, including adhesins such as filamentous hemagglutinin (FHA) and fimbriae, as well as toxins such as the bifunctional adenylate cyclase/hemolysin (ACY). Previous studies showed that in the Bvgi phase, FHA and fimbriae continue to be expressed, but ACY expression is significantly downregulated. In this report, we determine …


Reticulospinal Neurons Receive Direct Spinobulbar Inputs During Locomotor Activity In Lamprey, James F. Einum, James T. Buchanan Sep 2004

Reticulospinal Neurons Receive Direct Spinobulbar Inputs During Locomotor Activity In Lamprey, James F. Einum, James T. Buchanan

Biological Sciences Faculty Research and Publications

Reticulospinal neurons of the lamprey brain stem receive rhythmic input from the spinal cord during locomotor activity. The goal of the present study was to determine whether such spinal input has a direct component to reticulospinal neurons or depends on brain stem interneurons. To answer this question, an in vitro lamprey brain stem-spinal cord preparation was used with a diffusion barrier placed caudal to the obex, separating the experimental chamber into two baths. Locomotor activity was induced in the spinal cord by perfusion of D-glutamate or N-methyl-DL-aspartate into the spinal cord bath. The brain stem bath was first perfused …


Genesis: The Evolution Of Biology, Michael Dietrich Sep 2004

Genesis: The Evolution Of Biology, Michael Dietrich

Dartmouth Scholarship

Review of Genesis: The Evolution of Biology by Jan Sapp, 2003.


Multiple Kh Domains Of Poly C Binding Protein Are Required For Its Trans-Activation On The Proximal Promoter Of The Mu-Opioid Receptor Gene, Adnan K. Malik Sep 2004

Multiple Kh Domains Of Poly C Binding Protein Are Required For Its Trans-Activation On The Proximal Promoter Of The Mu-Opioid Receptor Gene, Adnan K. Malik

Seton Hall University Dissertations and Theses (ETDs)

The mu-opioid receptor (MOR) has been shown to mediate morphine induced analgesia, addiction, and tolerance. The expression of the major product of the MOR (MOR-1) gene has been found to be driven by two promoters, a distal promoter and a proximal promoter. The proximal promoter region has been shown in previous studies to be the major promoter for the regulation of MOR gene transcription in the adult mouse brain and embryonic development. Recent studies have shown that single-stranded DNA binding proteins (such as Poly C Binding Protein) are involved in transcriptional regulation of mouse MOR gene. Poly C binding protein …


Cholinergic Modulation Of The Locomotor Network In The Lamprey Spinal Cord, Katharina A. Quinlan, Peter G. Placas, James T. Buchanan Sep 2004

Cholinergic Modulation Of The Locomotor Network In The Lamprey Spinal Cord, Katharina A. Quinlan, Peter G. Placas, James T. Buchanan

Biological Sciences Faculty Research and Publications

Acetylcholine (ACh) was found here to be a strong modulator of swimming activity in the isolated spinal cord preparation of the adult lamprey (Ichthyomyzon unicuspis). During fictive swimming induced with either D-glutamate or N-methyl-D-aspartate, addition of ACh (200 µM) significantly reduced the cycle period of ventral root bursts to 54%, intersegmental phase lag to 32%, and ventral root burst proportion to 80% of control levels. Effects of ACh were apparent at concentrations as low as 1 µM. Both nicotinic and muscarinic receptors are involved, in that application of either nicotinic or muscarinic agonists alone significantly reduced cycle …


Response Of Brood-Parasitic Bronzed Cowbird To Playback Of The Song Of Audubon's Oriole, Steven G. Monk, Timothy Brush Sep 2004

Response Of Brood-Parasitic Bronzed Cowbird To Playback Of The Song Of Audubon's Oriole, Steven G. Monk, Timothy Brush

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

ABSTRACT—In the Lower Rio Grande Valley of South Texas, Audubon’s orioles (Icterus graduacauda) have declined substantially in the past 50 y, probably due to habitat loss, fragmentation, and brood parasitism by bronzed cowbirds (Molothrus aeneus). Tape playback of the song of Audubon’s oriole, originally intended to better survey the oriole, also attracted bronzed cowbirds. Bronzed cowbirds flew silently into the nearest tree in 14.1% of 234 playbacks, whereas Audubon’s orioles responded vocally or flew toward the recorder in 15.8% of playbacks. Bronzed cowbirds might use vocalizations of Audubon’s oriole as a cue to find breeding pairs or nests of this …


Woodland Amphibian Distribution In Parks And Greenspaces Of The Portland, Oregon Metropolitan Area: A Multiple Scale Investigation, Laura A. Roberts Aug 2004

Woodland Amphibian Distribution In Parks And Greenspaces Of The Portland, Oregon Metropolitan Area: A Multiple Scale Investigation, Laura A. Roberts

Dissertations and Theses

Loss of biodiversity due to habitat fragmentation is worldwide problem. With growing human populations and increasing urbanization, it is a necessity to conduct studies on wildlife occurring in urban areas. Currently there is a deficit of research investigating woodland amphibians in urban environments. My objectives were to describe amphibian species richness and abundance in the Portland, Oregon, Metropolitan region, and relate patterns of variation to variables at three increasingly large spatial scales: 1) local microenvironmental (i.e. amphibian/substrate interaction), (2) macrohabitat/patch (i.e. park or greenspace), and 3) landscape (surrounding parks and greenspaces). Environmental variables occurring within the three spatial scales were …


Chloroplast Dna Rearrangements In Campanulaceae: Phylogenetic Utility Of Highly Rearranged Genomes, Mary E. Cosner, Linda A. Raubeson, Robert K. Jansen Aug 2004

Chloroplast Dna Rearrangements In Campanulaceae: Phylogenetic Utility Of Highly Rearranged Genomes, Mary E. Cosner, Linda A. Raubeson, Robert K. Jansen

All Faculty Scholarship for the College of the Sciences

Background

The Campanulaceae (the "hare bell" or "bellflower" family) is a derived angiosperm family comprised of about 600 species treated in 35 to 55 genera. Taxonomic treatments vary widely and little phylogenetic work has been done in the family. Gene order in the chloroplast genome usually varies little among vascular plants. However, chloroplast genomes of Campanulaceae represent an exception and phylogenetic analyses solely based on chloroplast rearrangement characters support a reasonably well-resolved tree.

Results

Chloroplast DNA physical maps were constructed for eighteen representatives of the family. So many gene order changes have occurred among the genomes that characterizing individual mutational …


Synaptic Transformations Underlying Highly Selective Auditory Representations Of Learned Birdsong, Melissa J. Coleman, Richard Mooney Aug 2004

Synaptic Transformations Underlying Highly Selective Auditory Representations Of Learned Birdsong, Melissa J. Coleman, Richard Mooney

WM Keck Science Faculty Papers

Stimulus-specific neuronal responses are a striking characteristic of several sensory systems, although the synaptic mechanisms underlying their generation are not well understood. The songbird nucleus HVC (used here as a proper name) contains projection neurons (PNs) that fire temporally sparse bursts of action potentials to playback of the bird's own song (BOS) but are essentially silent when presented with other acoustical stimuli. To understand how such remarkable stimulus specificity emerges, it is necessary to compare the auditory-evoked responsiveness of the afferents of HVC with synaptic responses in identified HVC neurons. We found that inactivating the interfacial nucleus of the nidopallium …


Sinusoidal Length Oscillation- And Receptor-Mediated Mrna Expression Of Myosin Isoforms And Α-Sm Actin In Airway Smooth Muscle, Melissa Wahl, Thomas J. Eddinger, Chi-Ming Hai Aug 2004

Sinusoidal Length Oscillation- And Receptor-Mediated Mrna Expression Of Myosin Isoforms And Α-Sm Actin In Airway Smooth Muscle, Melissa Wahl, Thomas J. Eddinger, Chi-Ming Hai

Biological Sciences Faculty Research and Publications

We tested the hypothesis that sinusoidal length oscillation and receptor activation interactively regulate the abundance of mRNA encoding α-smooth muscle (α-SM) actin and myosin isoforms in intact bovine tracheal smooth muscle. We found that sinusoidal length oscillation significantly downregulated abundance of mRNA encoding α-SM actin mRNA in unstimulated tissues but not in histamine- and carbachol-activated tissues. This observation suggests antagonistic interactions between mechanical stretch and receptor-mediated signal transduction in regulating the abundance of mRNA encoding α-SM actin in intact airway smooth muscle. This pattern of antagonistic interaction was also observed in cholinergic receptor activation experiments. Whereas carbachol significantly upregulated myosin …


Characterization Of A Catechol-Type Siderophore And The Detection Of A Possible Outer Membrane Receptor Protein From Rhizobium Leguminosarum Strain Iari 312., Brianne Lee Clark Aug 2004

Characterization Of A Catechol-Type Siderophore And The Detection Of A Possible Outer Membrane Receptor Protein From Rhizobium Leguminosarum Strain Iari 312., Brianne Lee Clark

Electronic Theses and Dissertations

Many gram-negative bacteria produce and secrete siderophores under iron-deficient conditions. Siderophores are low molecular weight compounds (600-1500 Daltons), which chelate ferric iron with an extremely high affinity, and the complex is actively transported across the outer and inner membranes of gram-negative bacteria. There are two main classes of siderophores: catechol and hydroxamate. Catechol-type siderophores chelate ferric iron via hydroxyl groups, and hydroxamate-type siderophores chelate ferric iron via a carbonyl group with an adjacent nitrogen. Rhizobia fix atmospheric nitrogen symbiotically in leguminous plants using the iron-containing enzyme nitrogenase. To satisfy their iron requirements, many rhizobia are known to produce siderophores. Rhizobium …