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Modulatory Efferent Morphology And Target Allocation With Co-Innervating Leech Motor Neurons, James Melchior

Masters Theses

The leech, Hirudo, has two efferents that converge upon the heart tube (HT) muscle; the segmentally iterated heart excitor motor neurons (HE), and the modulatory heart accessory neurons (HA). Using intracellular dye injections and antibody labeling, we were able to visualize and distinguish the morphologies of these two efferents. We found that HA(5) provides dense coverage of the anterior segments of heart tube muscle and extends along the HT into the posterior segments 6 and 7, while HA(6) projects centrally for several segments before extending into the periphery. HA(5) and HA(6) homologs show little or no overlap on HT …

Most Caenorhabditis Elegans Micrornas Are Individually Not Essential For Development Or Viability, Eric A. Miska, Ezequiel Alvarez-Saavedra, Allison L. Abbott, Nelson C. Lau, Andrew B. Hellman, Shannon M. Mcgonagle, David P. Bartel, Victor R. Ambros, H. Robert Horvitz

Biological Sciences Faculty Research and Publications

MicroRNAs (miRNAs), a large class of short noncoding RNAs found in many plants and animals, often act to post-transcriptionally inhibit gene expression. We report the generation of deletion mutations in 87 miRNA genes in Caenorhabditis elegans, expanding the number of mutated miRNA genes to 95, or 83% of known C. elegans miRNAs. We find that the majority of miRNAs are not essential for the viability or development of C. elegans, and mutations in most miRNA genes do not result in grossly abnormal phenotypes. These observations are consistent with the hypothesis that there is significant functional redundancy among miRNAs …

Implications Of Introduced Mule Deer On Santa Catalina Island, California : Their Impacts, Population Ecology, And Management, Thad A. Manuwal

Theses and Dissertations

A small group of mule deer were introduced to Santa Catalina Island in the early
1930s. The mule deer population increased through the 1940s and 1950s and remains widespread and abundant today. Large browsing ungulates are not native to Santa Catalina Island and there is concern that nonnative mule deer are damaging endemic trees and shrubs on the island when foraging. This study was designed to develop quantitative information on diets, foraging behavior, movements, and population biology of mule deer on Catalina Island.

Diet analysis indicated mule deer are consuming a wide variety of native and
endemic plants found on …

Pattern Analysis Of Microtubule-Polymerizing And -Depolymerizing Agent Combinations As Cancer Chemotherapies, Carol A. Heckman, S. O. Uppal, Y. Li, E. Wendt, M. L. Cayer, J. Barnes, D. Conway, N. Boudreau

Biological Sciences Faculty Publications

Subcellular distribution of mass can be analyzed by a technique that involves culturing cells on interferometers and digitizing their interference contours. Contour sampling resulted in 102 variables per cell, which were predictors of oncogenic transformation. Cell phenotypes can be deconstructed by use of latent factors, which represent the covariance of the real variables. The reversal of the cancertype phenotype by a combination of microtubule- stabilizing and -depolymerizing agents was described previously. The implications of these results have been explored by clinicians who treated patients with the combination of docetaxel and vinorelbine (Navelbine®). The current study was performed to determine the …

Evalution Of The Efficacy Of The Photosystem Ii Inhibitor Dcmu In Periphyton And Its Effects On Nontarget Microorganisms And Extracellular Enzymatic Reactions, Steven N. Francoeur, Audrey C. Johnson, Kevin A. Kuehn, Robert K. Neely

Faculty Publications

We examined the efficacy of the photosystem II inhibitor 3-(3,4-diclorophenyl)-1,1-dimethyl urea (DCMU) for inhibition of algal photosynthesis in periphyton associated with submerged decomposing litter of Typha angustifolia. We also investigated the possible nontarget effects of DCMU exposure on heterotrophic microorganisms (i.e., bacteria and fungi) and extracellular enzyme activity associated with decaying litter. Standing-dead Typha leaf litter was submerged for 34 and 73 d, returned to the laboratory, and used for controlled laboratory experiments that examined the effect of DCMU on algal ([¹⁴C]bicarbonate, pulse-amplitude modulated fluorometry), bacterial ([³H]leucine), and fungal ([¹⁴C]acetate) production. Simultaneous assays …

Mapk Survival Signaling In Melanoma, Matthew W. Vanbrocklin

Dissertations

Extracellular signals activate mitogen-activated protein kinase (MAPK) cascades potentiating biological activities such as cell proliferation, differentiation, and survival. Constitutive activation of MAPK signaling pathways is implicated in the development and progression of many human cancers, including melanoma. Mutually exclusive activating mutations in NRAS or BRAF are found in ∼85% of all melanomas resulting in constitutive activation of the MAPK pathway (RAS-BRAF-MEK-ERK-RSK). We have previously demonstrated that inhibition of this pathway with small molecule MEK inhibitors selectively induces apoptosis in human melanoma cells both in vitro and in vivo, but not in normal melanocytes. These results support the notion that the …

A Statistical Appraisal Of Disproportional Versus Proportional Microbial Source Tracking Libraries, Brian J. Robinson, Kerry J. Ritter, Rudolph D. Ellender

Faculty Publications

Library-based microbial source tracking (MST) can assist in reducing or eliminating fecal pollution in waters by predicting sources of fecal-associated bacteria. Library-based MST relies on an assembly of genetic or phenotypic "fingerprints" from pollution-indicative bacteria cultivated from known sources to compare with and identify fingerprints of unknown origin. The success of the library-based approach depends on how well each source candidate is represented in the library and which statistical algorithm or matching criterion is used to match unknowns. Because known source libraries are often built based on convenience or cost, some library sources may contain more representation than others. Depending …

Spatial Ecology Of The Desert Tortoise: Sampling Frequency And Biological Influences, Meagan L. Harless

Loma Linda University Electronic Theses, Dissertations & Projects

Understanding the spatial ecology of an animal is crucial for making positive efforts to provide for its recovery. As a part of this understanding, home range estimates are used to answer a variety of questions in ecological studies. However, home range estimates based on a collection of radio-telemetry locations are sensitive to methodological variables, such as sample size, sampling frequency, and the choice of estimator. Further confounding these estimates are a number of physical, social, and ecological factors. Identifying the main determinants of space use patterns by a species may aid conservation efforts.

The Desert Tortoise (Gopherus agassizii)of the …

Vertebrate Osmoregulation: A Student Laboratory Exercise Using Teleost Fish, Bernard Rees

Biological Sciences Faculty Publications

Anaerobic metabolism is recruited in vertebrates under conditions of intense exercise or lowered environmental oxygen availability (hypoxia), typically resulting in the accumulation of lactate in blood and tissues. Lactate will be cleared over time after the reoxygenation of tissues, eventually returning to control levels. Here, we present a laboratory exercise developed as part of an upper-level vertebrate physiology class that demonstrates the effects of exercise and hypoxia exposure on blood lactate in fish and the subsequent decrease in lactate during recovery. Typically, the results obtained by students demonstrate that both treatments cause significant increases in blood lactate concentrations (two to …

Fundulus As The Premier Teleost Model In Environmental Biology: Opportunities For New Insights Using Genomics, Bernard Rees

Biological Sciences Faculty Publications

A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these …

Designation Of A Neotype For Leptodactylus Gracilis (Duméril And Bibron, 1840) (Amphibia: Leptodactylidae), Rafael O. De Sá, A. Dubois, A. Ohler

Biology Faculty Publications

The examination of the preserved specimens in the herpetological collection of the Museum National d'Histoire Naturelle, along with a review of the original literature, indicates that no extant specimen can be undoubtedly identified as the holotype of Leptodactylus gracilis (DumCri.l and Bibron, 1840). Furthermore, it revealed that the type locality recently assigned to this taxon is in error.

The Emergence Of Sex, Ursula Goodenough

Biology Faculty Research

Biological traits, the foci of natural selection, are by definition emergent from the genes, proteins, and other “nothing-buts” that constitute them. Moreover, and with the exception of recently emergent “spandrels,” each can be accorded a teleological dimension—each is “for” some purpose conducive to an organism's continuation. Sex, which is “for” the generation of recombinant genomes, may be one of the most ancient and ubiquitous traits in biology. In the course of its evolution, many additional traits, such as gender and nurture, have emerged. Patterns of sexual exchange are the basis for patterns of biological evolution and are central to the …

Prey Naiveté: Evolutionary And Ecological Implications, Jonathan G. Cox

All-Inclusive List of Electronic Theses and Dissertations

Despite its ecological importance, the concept of prey naivete has become a biological truism that receives little study. I explored the evolution of naivete and its likely influence on two major ecological patterns: a) the historically greater destructiveness of freshwater predator introductions, and b) the greater strength of aquatic trophic cascades. In a review of the ecological literature, I demonstrate that the conditions for the evolution of naivete (isolation) exist in freshwater habitats at multiple spatial scales. In addition, I show that freshwater prey exhibit naivete which could be responsible for the high impacts of freshwater predator introductions. I then …

Compromised Weaponry Enhances Crayfish Tailflipping, Sandra Y. Espinoza, Zen Faulkes

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

As a defense strategy, many crustaceans perform one of two well described stereotyped single fast tailflips (~6 ms in adult crayfish), which are triggered by a neural circuit that includes medial giant interneurons (MG) and lateral giant interneurons (LG). Tailflips can also occur without these giant interneurons firing, however; these non-giant tailflips are variable, repetitive, and significantly longer (~150 ms). Previous work showed that crayfish exposed to natural stimulus respond with a non-giant tailflip significantly faster than when presented with an artificial stimulus and that complete removal of claws lowered tailflipping threshold. We tested whether compromising weapons would influence tailflipping. …

Changes In Shell Morphology Of Elimia Comalensis (Gastropoda: Pleuroceridae) From The Edwards Plateau, Texas, Russell L. Minton, Scott A. Reese, Kim Swanger, Kathryn E. Perez, David M. Hayes

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

Species in the pleurocerid genus Elimia are important components of freshwater systems in the eastern United States, but little is known about their natural history. Using dual-simultaneous linear regression and principal components analyses, we show patterns of morphological change in two populations of E. comalensis from the Edwards Plateau, Texas. Both populations had similar rates of change for all shell measurements analyzed, and both showed similar decreases in growth as total length of shell increased. However, the size at which growth slowed was different between populations, and small shells tended to have a consistent shape, while larger shells were more …

Mechanisms Of Covalent Self-Assembly Of The Azoarcus Ribozyme From Four Fragment Oligonucleotides, Will E. Draper, Eric John Hayden, Niles Lehman

Chemistry Faculty Publications and Presentations

RNA oligomers of length 40–60 nt can self-assemble into covalent versions of the Azoarcus group I intron ribozyme. This process requires a series of recombination reactions in which the internal guide sequence of a nascent catalytic complex makes specific interactions with a complement triplet, CAU, in the oligomers. However, if the CAU were mutated, promiscuous self-assembly may be possible, lessening the dependence on a particular set of oligomer sequences. Here, we assayed whether oligomers containing mutations in the CAU triplet could still self-construct Azoarcus ribozymes. The mutations CAC, CAG, CUU and GAU all inhibited self-assembly to some degree, but did …

Bioluminescence In A Complex Coastal Environment: 2. Prediction Of Bioluminescent Source Depth From Spectral Water-Leaving Radiance, Matthew J. Oliver, Mark A. Moline, Curtis D. Mobley, Lydia Sundman, Oscar M.E. Schofield

Biological Sciences

Many bioluminescence observations are made from the ocean's surface. However, the depth of the bioluminescent source is difficult to estimate on the basis of surface observations alone, given the variable light attenuation of unknown concentrations of water column constituents such as phytoplankton, colored dissolved organic matter, and detritus. Part 1 of this paper showed that bioluminescent water-leaving radiance signals are detectable, even in extremely turbid and dynamic coastal waters. Here, in part 2 of this paper, we analyze the water-leaving radiance patterns of bioluminescence modeled by HydroLight 4.2 to determine if the depth of the bioluminescent source can be estimated …

Evidence Of Compromised Blood-Spinal Cord Barrier In Early And Late Symptomatic Sod1 Mice Modeling Als, Svitlana N. Garbuzova-Davis, Samuel Saporta, Edward M. Haller, Irina Kolomey, Steven P. Bennett, Huntington Potter, Paul R. Sanberg

Integrative Biology Faculty and Staff Publications

Background: The blood-brain barrier (BBB), blood-spinal cord barrier (BSCB), and blood-cerebrospinal fluid barrier (BCSFB) control cerebral/spinal cord homeostasis by selective transport of molecules and cells from the systemic compartment. In the spinal cord and brain of both ALS patients and animal models, infiltration of T-cell lymphocytes, monocyte-derived macrophages and dendritic cells, and IgG deposits have been observed that may have a critical role in motor neuron damage. Additionally, increased levels of albumin and IgG have been found in the cerebrospinal fluid in ALS patients. These findings suggest altered barrier permeability in ALS. Recently, we showed disruption of the BBB and …

Temperature Effects On Metabolic Rate Of Juvenile Pacific Bluefin Tuna Thunnus Orientalis, Jason M. Blank, Jeffery M. Morrissette, Charles J. Farwell, Mathew Price, Robert J. Schallert, Barbara A. Block

Biological Sciences

Pacific bluefin tuna inhabit a wide range of thermal environments across the Pacific ocean. To examine how metabolism varies across this thermal range, we studied the effect of ambient water temperature on metabolic rate of juvenile Pacific bluefin tuna, Thunnus thynnus, swimming in a swim tunnel. Rate of oxygen consumption (M_O2) was measured at ambient temperatures of 8–25°C and swimming speeds of 0.75–1.75 body lengths (BL) s^–1. Pacific bluefin swimming at 1 BL s^–1 per second exhibited a U-shaped curve of metabolic rate vs ambient temperature, with a thermal minimum zone between …

Structural Biology: A Receptor Unlocked, Stephen R. Sprang

Biological Sciences Faculty Publications

No abstract provided.

Regeneration Of Retinotectal Projections After Optic Tectum Removal In Adult Newts, Mitsumasa Okamoto, Hatsuki Ohsawa, Toshinori Hayashi, Katsushi Owaribe, Panagiotis A. Tsonis

Biology Faculty Publications

Purpose: When injured, the adult newt possesses the remarkable capability to regenerate tissues and organs with return of function and physiology. One example is the newt eye, in which regeneration can restore normal vision if the retina or lens has been removed. We wanted to examine how the retinotectal projections regenerate after removal of the brain’s optic tectum and establish this animal as a model for retinal projection as well as a central nervous system regeneration model.

Nodal Signaling Is Required For Closure Of The Anterior Neural Tube In Zebrafish, Allisan Aquilina-Beck, Kristine Ilagan, Qin Liu, Jennifer O. Liang

Biology Faculty Research

Background: Nodals are secreted signaling proteins with many roles in vertebrate development. Here, we identify a new role for Nodal signaling in regulating closure of the rostral neural tube of zebrafish.

Genomic Resources For Myzus Persicae: Est Sequencing, Snp Identification, And Microarray Design, John S. Ramsey, Alex C. C. Wilson, Marin De Vos, Qi Sun, Cecilia Tamborindeguy, Agnese Winfield, Gaynor Malloch, Dawn M. Smith, Brian Fenton, Stewart M. Gray, Georg Jander

Biology Articles and Papers

Backgorund

The green peach aphid, Myzus persicae (Sulzer), is a world-wide insect pest capable of infesting more than 40 plant families, including many crop species. However, despite the significant damage inflicted by M. persicae in agricultural systems through direct feeding damage and by its ability to transmit plant viruses, limited genomic information is available for this species.

Results

Sequencing of 16 M. persicae cDNA libraries generated 26,669 expressed sequence tags (ESTs). Aphids for library construction were raised on Arabidopsis thaliana, Nicotiana benthamiana, Brassica oleracea, B. napus, and Physalis floridana (with and without Potato leafroll virus infection). The …

Additive And Synergistic Bactericidal Activity Of Antibodies Directed Against Minor Outer Membrane Proteins Of Neisseria Meningitidis, Vincent E. Weynants, Christiane M. Feron, Karine K. Goraj, Martine P. Bos, Philippe A. Denoeal, Vincent G. Verlant, Jan Tommassen, Ian R. A. Peak, Ralph C. Judd, Michael P. Jennings, Jan T. Poolman

Biological Sciences Faculty Publications

Neisseria meningitidis serogroup B is a major cause of bacterial meningitis in younger populations. The available vaccines are based on outer membrane vesicles obtained from wild-type strains. In children less than 2 years old they confer protection only against strains expressing homologous PorA, a major, variable outer membrane protein (OMP). We genetically modified a strain in order to eliminate PorA and to overproduce one or several minor and conserved OMPs. Using a mouse model mimicking children's PorA-specific bactericidal activity, it was demonstrated that overproduction of more than one minor OMP is required to elicit antibodies able to induce complement-mediated killing …

Cerebrospinal Fluid And Serum Biomarkers Of Cerebral Malaria Mortality In Ghanaian Children, Winston Anderson

Department of Biology Faculty Publications

Plasmodium falciparum can cause a diffuse encephalopathy known as cerebral malaria (CM), a major contributor to malaria associated mortality. Despite treatment, mortality due to CM can be as high as 30% while 10% of survivors of the disease may experience short- and long-term neurological complications. The pathogenesis of CM and other forms of severe malaria is multi-factorial and appear to involve cytokine and chemokine homeostasis, inflammation and vascular injury/repair. Identification of prognostic markers that can predict CM severity will enable development of better intervention.Postmortem serum and cerebrospinal fluid (CSF) samples were obtained within 2-4 hours of death in Ghanaian children …

A Mutant Dec-1 Transgene Induces Dominant Female Sterility In Drosophila Melanogaster, Daniel K. Spangenberg, Gail L. Waring

Biological Sciences Faculty Research and Publications

The Drosophila dec-1 gene produces three proproteins required for female fertility and eggshell assembly. The three proproteins are distinguished by their C termini. Fc106, the most abundant proprotein, is cleaved within the vitelline membrane to three mature derivatives in a developmentally regulated manner. To define sequences within fc106 that are critical for its function, we created wild-type and mutant versions of an fc106 cDNA transgene. The functional consequences of the mutations were assessed in dec-1⁴, a female-sterile splicing mutant that does not produce the fc106 isoform. The fertility of dec-1⁴ females was restored by the introduction of …

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 …

Bio Buzz Newsletter, Issue 1, November 2007, Department Of Biology

Biology Buzz Newsletter

Denison University, Department of Biology newsletter for 2007.

Sporophytic Inbreeding Depression In Mosses Occurs In A Species With Separate Sexes But Not In A Species With Combined Sexes, Philip J. Taylor, Sarah M. Eppley, Linley K. Jesson

Biology Faculty Publications and Presentations

Inbreeding depression is a critical factor countering the evolution of inbreeding and thus potentially shaping the evolution of plant sexual systems. Current theory predicts that inbreeding depression could have important evolutionary consequences, even in haploid-dominant organisms. To date, no data have been reported on inbreeding depression in moss species. Here, we present data on the magnitude of inbreeding depression in sporophytic traits of moss species with contrasting breeding systems. In eratodon purpureus (Ditrichaceae), a moss species with separate sexes, self-fertilizations between sibling gametophytes (intergametophytic selfing) significantly reduced fitness in two of four traits quantified, with seta length and capsule length …

Re-Occurrence Of The Tropical Green Macroalga, Penicillus Capitatus (Chlorophyta: Bryopsidales), In Lower Laguna Madre Of South Texas., Joseph L. Kowalski, Donald L. Hockaday, Gilbert H. Boza Jr., Hudson R. Deyoe

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

The siphonaceous green alga Penicillus capitatus Lamarck is a common macroalga of the Carribean and Gulf of Mexico (Littler & Littler 2000). This shaving brush-shaped macroalga was a common inhabitant of the Lower Laguna Madre Texas (LLM) until about 40 years ago when the population was decimated following a salinity decline in the fall of 1959, another salinity reduction due to Hurricane Carla in 1961, and finally a severe freeze in 1962 (Sorensen 1963). Since that time, there have been no reports of P. capitatus in the LLM. During a reconnaissance trip in July 2006, a small population was found …