Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Biology

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 33091 - 33120 of 39346

Full-Text Articles in Entire DC Network

Predicting Risk To Biodiversity As A Function Of Aquifer Pressure In Gab Mound Springs, A. J. Tyre, Brigitte Tenhumberg, H.P. Possingham Dec 2001

Predicting Risk To Biodiversity As A Function Of Aquifer Pressure In Gab Mound Springs, A. J. Tyre, Brigitte Tenhumberg, H.P. Possingham

School of Biological Sciences: Faculty Publications

Plants and aquatic invertebrates endemic to mound springs of the Great Artesian Basin (GAB) of Australia are of national biodiversity significance. Springs occur in groups, and current survey data suggest that local extinction and recolonisation within a group does occur naturally. Mound spring fauna are therefore good examples of true metapopulations, and any study of the environmental impacts on these systems must take this into account. Use of GAB water leads to drawdown of the pressure in the aquifer. This can potentially impact mound spring flora and fauna in two ways. First, as pressure decreases, so does flow from spring …


Proprioception, Non-Law, And Biolegal History, Owen D. Jones Dec 2001

Proprioception, Non-Law, And Biolegal History, Owen D. Jones

Vanderbilt Law School Faculty Publications

This Article explores several advantages of incorporating into law various insights from behavioral biology about how and why the brain works as it does. In particular, the Article explores the ways in which those insights can help illuminate the deep structure of human legal systems. That effort is termed "biolegal history."


The Effect Of Thermal Stress On The Mating Behavior Of Three Drosophila Species, Zachary J. Patton, Robert A. Krebs Nov 2001

The Effect Of Thermal Stress On The Mating Behavior Of Three Drosophila Species, Zachary J. Patton, Robert A. Krebs

Biological, Geological, and Environmental Faculty Publications

Selection may act on the weakest link in fitness to change how a species adapts to an environmental stress. For many species, this limitation may be reproduction. After adult Drosophila melanogaster, Drosophila simulans, and Drosophila mojavensis males were exposed to varying levels of thermal stress well below those that endanger life, courtship and mating frequency declined. The regression coefficients of both courtship and mating success did not differ significantly between D. melanogaster and D. simulans males. In contrast, significant differences were present between the two cosmopolitan species and D. mojavensis. Courtship frequency decreased at a much slower rate in D. …


Fisheries Research Report No. 136 - Assessment Of Gonad Staging Systems And Other Methods Used In The Study Of The Reproductive Biology Of Narrow-Barred Spanish Mackerel, Scomberomorus Commerson, In Western Australia, Michael C. Mackie, Paul Lewis Nov 2001

Fisheries Research Report No. 136 - Assessment Of Gonad Staging Systems And Other Methods Used In The Study Of The Reproductive Biology Of Narrow-Barred Spanish Mackerel, Scomberomorus Commerson, In Western Australia, Michael C. Mackie, Paul Lewis

Fisheries Research Reports

Recent research by the Department of Fisheries in Western Australia into the reproductive biology of narrow-barred Spanish mackerel has required the use of various field and laboratory techniques. This report documents the procedures and adaptations of some of these techniques. Assessment and development of illustrated, relevant macroscopic and microscopic staging systems were of particular focus because both have been essential components of the research. The simplified and more reliable macroscopic staging system we developed allowed full use of all gonad samples and a more complete (albeit less distinct) overview of the seasonal pattern of gonad reproductive development. This macroscopic staging …


Re-Evaluating Nadph-Diaphorase Histochemistry As An Indicator Of Nitric Oxide Synthase: An Examination Of The Olfactory System Of Coho Salmon (Oncorhynchus Kisutch), Sean C. Lema, Gabrielle A. Nevitt Nov 2001

Re-Evaluating Nadph-Diaphorase Histochemistry As An Indicator Of Nitric Oxide Synthase: An Examination Of The Olfactory System Of Coho Salmon (Oncorhynchus Kisutch), Sean C. Lema, Gabrielle A. Nevitt

Biological Sciences

The NADPH-diaphorase (NADPH-d) histochemical technique is commonly used to localize the nitric oxide (NO)-producing enzyme NO synthase (NOS) in neural tissues. In the olfactory tissues of vertebrates, however, NADPH-d staining can be present without the detection of NOS by other methods. We used pharmacological controls to determine whether NADPH-d staining was indicative of NOS in olfactory tissues from coho salmon (Oncorhynchus kisutch). We also compared NADPH-d staining with immunoreactivity to NOS. NADPH-d staining localized to the olfactory epithelium and to the glomerular layer of the olfactory bulb. Two NOS inhibitors, L-N-nitroarginine and L-N-methyl-L-arginine, failed …


Structural And Functional Analysis Of Interhelical Interactions In The Human Immunodeficiency Virus Type 1 Gp41 Envelope Glycoprotein By Alanine-Scanning Mutagenesis, Min Lu, Marisa O. Stoller, Shilong Wang, Jie Liu, Melinda B. Fagan, Jack H. Nunberg Nov 2001

Structural And Functional Analysis Of Interhelical Interactions In The Human Immunodeficiency Virus Type 1 Gp41 Envelope Glycoprotein By Alanine-Scanning Mutagenesis, Min Lu, Marisa O. Stoller, Shilong Wang, Jie Liu, Melinda B. Fagan, Jack H. Nunberg

Biological Sciences Faculty Publications

Membrane fusion by human immunodeficiency virus type 1 (HIV-1) is promoted by the refolding of the viral envelope glycoprotein into a fusion-active conformation. The structure of the gp41 ectodomain core in its fusion-active state is a trimer of hairpins in which three antiparallel carboxyl-terminal helices pack into hydrophobic grooves on the surface of an amino-terminal trimeric coiled coil. In an effort to identify amino acid residues in these grooves that are critical for gp41 activation, we have used alanine-scanning mutagenesis to investigate the importance of individual side chains in determining the biophysical properties of the gp41 core and the membrane …


Host-Switching Does Not Circumvent The Ni-Based Defence Of The Ni Hyperaccumulator Streptanthus Polygaloides (Brassicaceae), Micheal A. Davis, Robert S. Boyd, James H. Cane Nov 2001

Host-Switching Does Not Circumvent The Ni-Based Defence Of The Ni Hyperaccumulator Streptanthus Polygaloides (Brassicaceae), Micheal A. Davis, Robert S. Boyd, James H. Cane

Faculty Publications

Elevated tissue concentrations of metals have been shown to defend metal-hyperaccumulating plants against both herbivores and pathogens. Tolerance of metal-based defences presents a challenge to herbivores, because heavy metals cannot be degraded or metabolized. One strategy that herbivores can employ to counter high-metal defences is dietary dilution, or host switching. Highly mobile herbivores are most likely to use this strategy, but less mobile lepidopteran larvae can also Improve their performance on toxic hosts if early instar development occurs on more favourable hosts. We examined the effects of host switching on growth and survival of a generalist folivore. Specifically, we tested …


Blood-Squirting Variability In Horned Lizards (Phrynosoma), Wade Sherbrooke, George Middendorf, C. Guyer Nov 2001

Blood-Squirting Variability In Horned Lizards (Phrynosoma), Wade Sherbrooke, George Middendorf, C. Guyer

Department of Biology Faculty Publications

Variability within the genus Phrynosoma in the occurrence of ocular-sinus blood-squirting, reportedly a defense used in canid encounters, is reviewed from the literature. Six species have been reported to squirt blood, and seven species remain unreported. Five of the latter species were tested in dog trials; one exhibited blood-squirting (Phrynosoma hernandesi), one exhibited precursor behaviors but failed to squirt blood (Phrynosoma ditmarsi), and three yielded negative results (Phrynosoma mcallii, Phrynosoma modestum, and Phrynosoma platyrhinos). Instances of blood-squirting in response to human encounters were collected and largely support the negative results for the three species P. mcallii, P. modestum, and P. …


Differential Expression Of Cadherin-2 And Cadherin-4 In The Developing And Adult Zebrafish Visual System, Qin Liu, S. G. Babb, Z. M. Novince, A. L. Doedens, J. Marrs, P. A. Raymond Nov 2001

Differential Expression Of Cadherin-2 And Cadherin-4 In The Developing And Adult Zebrafish Visual System, Qin Liu, S. G. Babb, Z. M. Novince, A. L. Doedens, J. Marrs, P. A. Raymond

Biology Faculty Research

Cadherins are homophilic cell adhesion molecules that control development of a variety of tissues and maintenance of adult structures. Although cadherins have been implicated in the development of the brain, including the visual system, in several vertebrate species, little is known of their role in zebrafish. In this study, we examined distribution of cadherin-2 (Cdh2, N-cadherin) in the visual system of developing and adult zebrafish using both immunocytochemical and in situ hybridization methods, and we compared Cdh2 distribution to that of the previously reported and closely related cadherin-4 (Cdh4, R-cadherin). As in other vertebrates, in zebrafish embryos Cdh2 was widely …


High Frequency Of Extra-Pair Paternity In Eastern Kingbirds, Michael T. Murphy, Diane L. Rowe, Robert C. Fleischer, Paul G. Wolf Nov 2001

High Frequency Of Extra-Pair Paternity In Eastern Kingbirds, Michael T. Murphy, Diane L. Rowe, Robert C. Fleischer, Paul G. Wolf

Biology Faculty Publications

Genetic parentage in the socially monogamous and territorial Eastern Kingbird( Tyrannust tyrannus) was examined in a central New York population by multilocus DNA fingerprinting. Extra-pair young were identified in 60% (12 of 20) of nests. Of the 64 nestlings profiled, 42% were sired by extra-pair males, but no cases of conspecific brood parasitism were detected. These results are markedly different from a previous electrophoretic study of the same species in a Michigan population, which reported 39% of nestlings were unrelated to one (typically the mother, quasiparasitismo)r both (conspecificb roodp arasitism) of the putative parents. In the New York population, extra-pairp …


High Frequency Of Extra-Pair Paternity In Eastern Kingbirds, Diane L. Rowe, Michael T. Murphy, Robert C. Fleischer, Paul G. Wolf Nov 2001

High Frequency Of Extra-Pair Paternity In Eastern Kingbirds, Diane L. Rowe, Michael T. Murphy, Robert C. Fleischer, Paul G. Wolf

Biology Faculty Publications and Presentations

Genetic parentage in the socially monogamous and territorial Eastern Kingbird( Tyrannust tyrannus) was examined in a central New York population by multilocus DNA fingerprinting. Extra-pair young were identified in 60% (12 of 20) of nests. Of the 64 nestlings profiled, 42% were sired by extra-pair males, but no cases of conspecific brood parasitism were detected. These results are markedly different from a previous electrophoretic study of the same species in a Michigan population, which reported 39% of nestlings were unrelated to one (typically the mother, quasiparasitismo)r both (conspecificb roodp arasitism) of the putative parents. In the New York population, extra-pairp …


Mammals Of Fort A. P. Hill, Caroline County, Virginia And Vicinity, A. Scott Bellows, Joseph C. Mitchell, John F. Pagels, Heather N. Mansfield Oct 2001

Mammals Of Fort A. P. Hill, Caroline County, Virginia And Vicinity, A. Scott Bellows, Joseph C. Mitchell, John F. Pagels, Heather N. Mansfield

Virginia Journal of Science

Fort A.P. Hill (APH) is a 30,329 ha military training installation (U.S. Army) located in the upper Coastal Plain of Caroline County, Virginia. It was formed in 1941 and named in honor of Civil War Confederate Lt. General Ambrose Powell Hill. The current landscape includes a mosaic of habitats that range from old fields to hardwood forests. Forty species of mammals are known to exist on or near the installation. These include one marsupial, five insectivores, 9 chiropterans, one lagomorph, 12 rodents, 10 carnivores, and one cervid. We have studied many of the species on APH since 1997. In this …


Cocaine- And Amphetamine-Regulated Transcript Peptide Modulation Of Voltage-Gated Ca2+ Signaling In Hippocampal Neurons, Elena (Olena) Petroff, Jianguo Chen, Pastor R. Couceyro, Toshinori Hoshi Oct 2001

Cocaine- And Amphetamine-Regulated Transcript Peptide Modulation Of Voltage-Gated Ca2+ Signaling In Hippocampal Neurons, Elena (Olena) Petroff, Jianguo Chen, Pastor R. Couceyro, Toshinori Hoshi

Department of Biology Faculty Scholarship and Creative Works

Administration of cocaine and amphetamine increases cocaine- and amphetamine-regulated transcript (CART) expression in the rat striatum (Douglass et al., 1995). CART mRNA is highly expressed in different parts of the human and rat brain, including hippocampus (Douglass et al., 1995; Couceyro et al., 1997; Kuhar and Yoho, 1999; Hurd and Fagergren, 2000). The presence of CART peptide 55-102 immunoreactivity in dense core vesicles of axon terminals suggests that the peptide may be released and may act as a neuromodulator (Smith et al., 1997) to induce neurophysiological and behavioral effects. Little is known, however, about CART peptide-responsive cells, receptor(s), or intracellular …


Bounce And Double Trill Songs Of Male And Female Western Screech-Owls: Characterization And Usefulness For Classification Of Sex, Brian L. Herting, James R. Belthoff Oct 2001

Bounce And Double Trill Songs Of Male And Female Western Screech-Owls: Characterization And Usefulness For Classification Of Sex, Brian L. Herting, James R. Belthoff

Biology Faculty Publications and Presentations

Both sexes of adult Western Screech-Owls (Otus kennicottii) sing in response to playback of conspecific song within their territories. Two primary songs are the bounce and double trill. Using sonographic analysis of tape-recorded vocalizations, our study quantified characterstics of bounce and double trill songs uttered by individuals within a population of Western Screech-Owls inhabiting riparian woodlands in southwestern Idaho. We asked if songs of males and females differed and, if so, how accurately could songs be classified by sex. On average, male bounce songs were ∼30% lower in frequency than bounce songs of females, but song duration, note duration, number …


Genetic Locus Required For Antigenic Maturation Of Rhizobium Etli Ce3 Lipopolysaccharide, Dominik M. Duelli, Andrea Tobin, Jodie M. Box, V.S. Kumar Kolli, Russell W. Carlson, K. Dale Noel Oct 2001

Genetic Locus Required For Antigenic Maturation Of Rhizobium Etli Ce3 Lipopolysaccharide, Dominik M. Duelli, Andrea Tobin, Jodie M. Box, V.S. Kumar Kolli, Russell W. Carlson, K. Dale Noel

Biological Sciences Faculty Research and Publications

Rhizobium etli modifies lipopolysaccharide (LPS) structure in response to environmental signals, such as low pH and anthocyanins. These LPS modifications result in the loss of reactivity with certain monoclonal antibodies. The same antibodies fail to recognize previously isolated R. etli mutant strain CE367, even in the absence of such environmental cues. Chemical analysis of the LPS in strain CE367 demonstrated that it lacked the terminal sugar of the wild-type O antigen, 2,3,4-tri-O-methylfucose. A 3-kb stretch of DNA, designated as lpe3, restored wild-type antigenicity when transferred into CE367. From the sequence of this DNA, five open reading frames …


Whence Meiosis?, Anne M. Villeneuve, Kenneth J. Hillers Sep 2001

Whence Meiosis?, Anne M. Villeneuve, Kenneth J. Hillers

Biological Sciences

Sexual reproduction predominates among eukaryotic organisms on our planet. While debate continues over why this should be so, burgeoning genomic and functional information now allows us to begin to think reasonably about some of the events that may have occurred to make sex possible in the first place.


Mitogen-Activated Protein Kinase Phosphorylates And Targets Inducible Camp Early Repressor To Ubiquitin-Mediated Destruction, Ghassan Yehia, Florence Schlotter, Reza Razavi, Alessandro Alessandrini, Carlos Molina Sep 2001

Mitogen-Activated Protein Kinase Phosphorylates And Targets Inducible Camp Early Repressor To Ubiquitin-Mediated Destruction, Ghassan Yehia, Florence Schlotter, Reza Razavi, Alessandro Alessandrini, Carlos Molina

Department of Biology Faculty Scholarship and Creative Works

Inducible cAMP early repressor (ICER) is an important mediator of cAMP antiproliferative activity that acts as a putative tumor suppressor gene product. In this study, we examined the regulation of ICER protein by phosphorylation and ubiquitination in human choriocarcinoma JEG-3 and mouse pituitary AtT20 cells. We found that cAMP stabilized ICER protein by inhibiting the mitogen-activated protein kinase (MAPK) cascade. Activation of the MAPK pathway increased ICER phosphorylation. ICER phosphorylation was abrogated by inhibition of the MAPK pathway either by cAMP or directly by the MAPK inhibitor PD098059. The MAPKs extracellular signal-regulated kinases 1 and 2 physically interact with ICER …


Effects Of Size And Temperature On Metabolic Rate, James Gillooly, James Brown, Geoffrey West, Van Savage, Eric Charnov Sep 2001

Effects Of Size And Temperature On Metabolic Rate, James Gillooly, James Brown, Geoffrey West, Van Savage, Eric Charnov

Biology Faculty & Staff Publications

We derive a general model, based on principles of biochemical kinetics and allometry, that characterizes the effects of temperature and body mass on metabolic rate. The model fits metabolic rates of microbes, ectotherms, endotherms (including those in hibernation), and plants in temperatures ranging from 0 to 40C. Mass - and temperature - compensated resting metabolic rates of all organisms are similar: The lowest (for unicellular organisms and plants) is separated from the highest (for endothermic vertebrates) by a factor of about 20. Temperature and body size are primary determinants of biological time and ecological roles.


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 …


Biology Department Publications: 2001, Sam Lindgren Sep 2001

Biology Department Publications: 2001, 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 2001. It indexes those publications available through major databases, and serves as an archival record of the Department’s robust scholarly contributions.


Stem Morphology And Anatomy In Amaranthus L. (Amaranthaceae)—Taxonomic Significance, Mihai Costea, Darleen A. Demason Sep 2001

Stem Morphology And Anatomy In Amaranthus L. (Amaranthaceae)—Taxonomic Significance, Mihai Costea, Darleen A. Demason

Biology Faculty Publications

The range of variation within the genus Amaranthus L. (Amaranthaceae) is described for a number of stem characters including: morphology, epidermis, primary stem vasculature and mechanism of secondary growth. The results provide new characters (phyllotaxy, complexity of leaf vascular supply and relative amount of secondary growth) that support (1) a new infrageneric classification (subgenus Amaranthus vs subgenus Albersia (Kunth)Gren. & Dodr.), and (2) the separation within the “hybridus” complex of cultivated amaranths (A. caudatus L., A. cruentus L., and A. hypochondriacus L.) from their presumed wild ancestors (A. hybridus L. subsp. quitensis (Kunth) Costea & Carretero, …


Structure Of The Rgrgs Domain Of P115rhogef, Zhe Chen, Clark D. Wells, Paul C. Sternweis, Stephen R. Sprang Sep 2001

Structure Of The Rgrgs Domain Of P115rhogef, Zhe Chen, Clark D. Wells, Paul C. Sternweis, Stephen R. Sprang

Biological Sciences Faculty Publications

p115RhoGEF, a guanine nucleotide exchange factor for Rho GTPase, is also a GTPase activating protein (GAP) for G12 and G13 heterotrimeric Gα subunits. Near its N-terminus, p115RhoGEF contains a domain (rgRGS) with remote sequence identity to RGS (regulators of G protein signaling) domains. The rgRGS domain is necessary but not sufficient for the GAP activity of p115RhoGEF. The 1.9 Å resolution crystal structure of the rgRGS domain shows structural similarity to RGS domains but possesses a C-terminal extension that folds into a layer of helices that pack against the hydrophobic core of the domain. Mutagenesis experiments show that …


Mutations In Sid2, A Novel Gene In Saccharomyces Cerevisiae, Cause Synthetic Lethality With Sic1 Deletion And May Cause A Defect During S Phase, Matthew D. Jacobson , '97, Claudia C. Muñoz , '99, Kirstin S. Knox , '99, Beth E. Williams , '01, Lenette L. Lu , '02, Frederick Cross , '78, Elizabeth Ann Vallen Sep 2001

Mutations In Sid2, A Novel Gene In Saccharomyces Cerevisiae, Cause Synthetic Lethality With Sic1 Deletion And May Cause A Defect During S Phase, Matthew D. Jacobson , '97, Claudia C. Muñoz , '99, Kirstin S. Knox , '99, Beth E. Williams , '01, Lenette L. Lu , '02, Frederick Cross , '78, Elizabeth Ann Vallen

Biology Faculty Works

SIC1 encodes a nonessential B-type cyclin/CDK inhibitor that functions at the G1/S transition and the exit from mitosis. To understand more completely the regulation of these transitions, Mutations causing synthetic lethality with sic1 Delta were isolated. In this screen, we identified a novel gene, SID2, which encodes an essential protein that appear., to be required for DNA replication or repair. sid2-1 sic1 Delta strains and sid2-21 temperature-sensitive strains arrest preanaphase as large-budded cells with a single nucleus, a short spindle, and an similar to 2C DNA content. RAD9, which is necessary for the DNA damage checkpoint, is required for the …


New Vistas For Developmental Biology, Scott F. Gilbert, R. Tuan Sep 2001

New Vistas For Developmental Biology, Scott F. Gilbert, R. Tuan

Biology Faculty Works

No abstract provided.


Inferring And Testing Hypotheses Of Cladistic Character Dependence By Using Character Compatibility, F. Robin O’Keefe, Peter J. Wagner Sep 2001

Inferring And Testing Hypotheses Of Cladistic Character Dependence By Using Character Compatibility, F. Robin O’Keefe, Peter J. Wagner

Biological Sciences Faculty Research

The notion that two characters evolve independently is of interest for two reasons. First, theories of biological integration often predict that change in one character requires complementary change in another. Second, character independence is a basic assumption of most phylogenetic inference methods, and dependent characters might confound attempts at phylogenetic inference. Previously proposed tests of correlated character evolution require a model phylogeny and therefore assume that nonphylogenetic correlation has a negligible effect on initial tree construction. This paper develops “tree-free” methods for testing the independence of cladistic characters. These methods can test the character independence model as a hypothesis before …


Genomes, Gould, And Emergence, Ursula Goodenough Sep 2001

Genomes, Gould, And Emergence, Ursula Goodenough

Biology Faculty Research

The publication of the human genome has elicited commentary to the effect that, since fewer genes were identified than anticipated, it follows that genes are less important to human biology than anticipated. The flaws in this syllogism are explained in the context of a treatise on how genomes operate and evolve and how genes function to produce embryos and brains. Most of our most cherished human traits are the result of the emergence of new properties from preexisting genetically scripted ideas, offering countless opportunities to celebrate the evolutionary process.


Precipitation And Temperature Effects On Populations Of Aedes Albopictus (Diptera : Culicidae): Implications For Range Expansion, B W. Alto, Steven A. Juliano Sep 2001

Precipitation And Temperature Effects On Populations Of Aedes Albopictus (Diptera : Culicidae): Implications For Range Expansion, B W. Alto, Steven A. Juliano

Faculty Publications – Biological Sciences

We investigated how temperature and precipitation regime encountered over the life cycle of Aedes albopictus (Skuse) affects populations. Caged populations of A. albopictus were maintained at 22, 26, and 30 degreesC. Cages were equipped with containers that served as sites for oviposition and larval development. All cages were assigned to one of three simulated precipitation regimes: (1) low fluctuation regime - water within the containers was allowed to evaporate to 90% of its maximum before being refilled, (2) high fluctuation regime - water was allowed to evaporate to 25% of its maximum before being refilled, and (3) drying regime - …


Functional And Structural Adaptations Of Skeletal Muscle To Microgravity, Robert H. Fitts, Danny R. Riley, Jeffrey J. Widrick Sep 2001

Functional And Structural Adaptations Of Skeletal Muscle To Microgravity, Robert H. Fitts, Danny R. Riley, Jeffrey J. Widrick

Biological Sciences Faculty Research and Publications

Our purpose is to summarize the major effects of space travel on skeletal muscle with particular emphasis on factors that alter function. The primary deleterious changes are muscle atrophy and the associated decline in peak force and power. Studies on both rats and humans demonstrate a rapid loss of cell mass with microgravity. In rats, a reduction in muscle mass of up to 37% was observed within 1 week. For both species, the antigravity soleus muscle showed greater atrophy than the fast-twitch gastrocnemius. However, in the rat, the slow type I fibers atrophied more than the fast type II fibers, …


Characterization Of Transepithelial Potential Oscillations In The Drosophila Malpighian Tubule, Edward M. Blumenthal Sep 2001

Characterization Of Transepithelial Potential Oscillations In The Drosophila Malpighian Tubule, Edward M. Blumenthal

Biological Sciences Faculty Research and Publications

The Malpighian tubule of Drosophila melanogaster is a useful model system for studying the regulation of epithelial ion transport. In acutely isolated tubules, the transepithelial potential (TEP) undergoes large oscillations in amplitude with a period of approximately 30s. The TEP oscillations are diminished by reductions in the peritubular chloride concentration in a manner consistent with their being caused by fluctuations in chloride conductance. The oscillations are eliminated by pretreating tubules with the calcium chelator BAPTA-AM, although removal of peritubular calcium has no effect, suggesting that the oscillations are a result of either the release of calcium from intracellular stores or …


Habitat Use, Population Density, And Home Range Of Elf Owls (Micrathene Whitneyi) At Santa Ana National Wildlife Refuge, Texas, Christopher Michael Gamel, Timothy Brush Sep 2001

Habitat Use, Population Density, And Home Range Of Elf Owls (Micrathene Whitneyi) At Santa Ana National Wildlife Refuge, Texas, Christopher Michael Gamel, Timothy Brush

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

We collected data on the habitat use, home range size, and population density of the Elf Owl (Micrathene Whitneyi Idonea) in the Santa Ana National Wildlife refuge (SANWR) Lower Rio Grande Valley, Texas. Fourteen nocturnal surveys in 1995 and 1996 indicated that Elf Owls used chaparral habitat (92%) more than riparian woodlands(8%). Habitats used had high foliage densities(greatest density = 2.5-3.0 m) with partial canopies (x = 3.8 +_ 0.36 m [+_SE] and semi-open understories (greatest density< 1 m). Unused chaparral habitat lacked high canopy coverage and had a denser understory, while riparian woodlands had greater canopyheights (• = 5.25 m) and open understories. Home range size determined by radiotelemetry averaged1.0.5+_0.33 ha (range = 0.24-2.60, N = 9). We estimated the maximum potential population size in SANWR to be 802 Elf Owls, assuming a home range size of 1.05 ha per breeding pair and saturation of preferred habitat.

-

Colectamos datos sobre el uso de habitat, tamafio del rango de hogar y densidad poblacional de Micrathene whitneyi idonea en el Refugio …