Biology Commons^™

Application Of Shortest-Path Network Analysis To Identify Genes That Modulate Longevity In Saccharomyces Cerevisiae, Jr Managbanag

Theses and Dissertations

Shortest-path network analysis was employed to identify novel genes that modulate longevity in the baker’s yeast Saccharomyces cerevisiae. Based upon a set of previously reported genes associated with increased life span, a shortest path network algorithm was applied to a pre-existing protein-protein interaction dataset in order to construct a shortest-path longevity network. To validate this network, the replicative aging potential of 88 single gene deletion strains corresponding to predicted components of the shortest path longevity network was determined. The 88 single-gene deletion strains identified by a network approach are significantly enriched for mutation conferring both increased and decreased replicative life …

Plumage Ornamentation As An Indicator Of Female Age And An Influence In Male Mate Choice In Protonotaria Citrea, The Prothonotary Warbler In Virginia., Terry Smith

Theses and Dissertations

Flamboyant plumage and ornamentation is common and well-known in male birds; it serves as a sexual display to attract potential mates. While flamboyant plumage is less common and usually more subtle in female birds, it does occur in some species such as Dark-Eyed Juncos (Junco hyemalis) and Prothonotary Warblers (Protonotaria citrea). Prothonotary Warblers display relatively subtle sexual dimorphism. This study examines variations in tail spot patterns in Prothonotary Warblers and relates those variations to age in females. Females with fewer than six spots tend to be two years old or younger; females with six spots or more tend to be …

The Effect Of Nacl On Akinete Differentiation In The Cyanobacterium Nostoc Punctiforme, Jonathan Heekin

Theses and Dissertations

Nostoc punctiforme is a nitrogen-fixing, symbiotic/free-living cyanobacterium. There has been a great deal of research conducted on the genomic nature of N. punctiforme as it pertains to its ecologically important role in the nitrogen cycle in varied environments around the world. My study concentrated on the dormant cell type known as the akinete. Increasing concentrations of NaCl were used to follow the growth phases from germination to akinete formation (lag phase-logarithmic growth phase-stationary phase). I found that increased salt concentrations caused N. punctiforme to form akinetes faster when compared to the control. Germination rates were not greatly increased or shortened …

The Ecology Of Fear: Oviposition And Colonization In Aquatic Systems, Leeanna Pletcher

Theses and Dissertations

Amphibians and aquatic invertebrates have complex life histories that link aquatic and terrestrial food webs. It has been suggested that amphibian reproduction is an important source of carbon to some aquatic systems. This process of energy flow may be shaped by shifts in habitat selection in response to predators. We hypothesized that predators decrease colonization and oviposition of prey, reducing active inputs. Thus predation risk is expected to shift the relative amounts of active and passive subsidies. We manipulated the presence of fish predators in aquatic mesocosms. Results suggest hylid treefrog eggs and hydrophilid beetles were less abundant in predator …

Effects Of Predation Risk, Density And Disease On Energy Efficiency In A Larval Anuran, Sarah Crane

Theses and Dissertations

Predation, density and disease affect behavior, morphology and growth. There is a lack of information on how these changes relate to efficiency of energy transfer in anuran larvae, although previous studies suggest that predation should decrease and competition should increase efficiency. Using a 2 x 2 factorial design, we manipulated predation presence and larval density to test how predation risk and density affect energy efficiency. During the experiment, approximately half of the tadpoles were infected by an unknown disease. Neither predation risk nor density affected assimilation or growth efficiency, despite changes in growth and development. Disease, however, decreased gut length …

Gliotoxin Production In Aspergillus Fumigatus, Susan Musyimi

Theses and Dissertations

Aspergillus fumigalus is a ubiquitous fungus that causes an infection called aspergillosis in immune-compromised surgery patients (Latge, 2001, 384; Bok et al. 2006). Aspergillosis cases have increased in the past decade due to the increasing number of patients undergoing immunosuppressive therapy and receiving organ transplants (Bok et al. 2006). Although there is still disagreement as to the causative agent of the symptoms accompanying aspergillosis, many scientists suspect that the compound, gliotoxin, plays a major role, hi this study, we compared the amounts of gliotoxin produced from clinical and environmental isolates of A. fumigatus. We hypothesized that the amount of gliotoxin …

Effect Of Thyroid Hormones On At1r Mrna Levels In Hek 293 Cells: Implications For Early-Onset Hypertension In Children Born Of Preeclamptic Women, Amanda Eddins

Theses and Dissertations

This experiment tested the effect of thyroid hormones, T3 or T4, on angiotensin II type 1 receptor mRNA levels in human embryonic kidney cells (HEK). Maternal preeclampsia is a prediction of higher ambulatory blood pressure (ABP) in the exposed offspring. The mother's blood pressure affects the blood pressure of the fetus since the placenta mediates blood flow. Thyroid hormone can increase production of angiotensinogen, which is a part of the renin-angiotensin system (RAS). RAS regulates blood pressure. Hypothesis: HEK 293 cells treated with T3 and T4 will have more angiotensin II type I receptors than those not treated with T3 …

Mechanical Abrasion And Electroporation In The Transformation Of Intact Pleurotus Ostreatus Hyphæ And Nutrient-Dependant Resistance To Hygromycin B, Alexander Cordesman

Theses and Dissertations

ABSTRACT 1: Abrasive treatment and subsequent electroporation of the basidiomycete Pleurotus ostreatus in a hypertonic buffer was investigated as a potential method of transforming of intact hyphæ. Mycelia, which are not capable of being transformed via electroporation due to interference by the cell wall, were abraded in an attempt to mechanically degrade the cell wall prior to electroporation. An electroporation field strength of 12,500 V/cm for 500 μs to 1.25 ms was found to be optimal based upon mortality effects. A 32 μm carborundum abrasive was initially evaluated but was quickly found to be inappropriately large so a corundum abrasive …

Camk-Ii Promotes Beta-Catenin-Dependent Transcription By Binding Flightless-I, Jamie Mcleod

Theses and Dissertations

Transient intracellular elevations of Ca2+ are common signaling mechanisms used to allosterically regulate proteins. One potential target of Ca2+ is Ca2+/calmodulin dependent protein kinase type II (CaMK-II). CaMK-II is a multi-functional protein kinase known to influence cellular pathways such as cell motility and cell cycle progression. Within the cell cycle, CaMK-II promotes the expression of the regulator protein cyclin D1, which is necessary for cell cycle progression. To further understand CaMK-II’s role in cyclin D1 expression, the binding partners of cytosolic CaMK-II were studied using mass spectrometry. Several proteins were identified including β actin, β tubulins, tropomodulin- 3 and Flightless-I. …

Role Of The Small Terminase Subunit Encoded By Staphylococcus Aureus Pathogenicity Island Sapi1 In Formation Of Sapi1 Transducing Particles, Nicholas Paul Olivarez

Theses and Dissertations

Staphylococcus aureus pathogenicity island SaPI1 is a genomic element that is mobilized and transduced at high frequency by helper phage 80α. SaPI1 encodes a small terminase protein that belongs to the phage small terminase subunit family. The presence of SaPI1-encoded small terminase suggests that it plays a role in SaPI1-specific packaging into transducing particles by complexing with the 80α large terminase subunit and redirecting recognition to a pac site on SaPI1 DNA from 80α DNA. The effects of deleting the small terminase genes in SaPI1 and in a prophage copy of 80α are consistent with this hypothesis. Induction of the …

Phylogeography Of The Livebearer Xenophallus Umbratilis (Teleostei: Poeciliidae): Glacial Cycles And Sea Level Change Predict Diversification Of A Freshwater Tropical Fish, Carissa Poole Jones

Theses and Dissertations

The biogeography of Central America is considered a classical case study in understanding the impact of vicariant events on patterns of biotic dispersal. While many biogeographers have focused on community composition and geographic limits of species at broad scales across Central America, much less work has focused on post-colonization diversification patterns at finer scales. The livebearing freshwater fish Xenophallus umbratilis presents an ideal system for determining the impact of recent earth history events on biodiversity in northern Costa Rica. Here, we test the hypothesis that marine inundation of the San Carlos and Northern Limón basins during the Miocene has caused …

Niche Separation Along Environmental Gradients As A Mechanism To Promote The Coexistence Of Native And Invasive Species, Edmund R. Priddis

Theses and Dissertations

Niche separation may be the key to promoting the long-term coexistence of introduced and native species. Physical alterations to the environment (habitat manipulation) or re-introducing native species to former habitats can exploit the maladapted traits of introduced species to create a refuge for native species. No two species have identical niches because evolutionary constraints differ between species with different evolutionary histories. Our objectives were to determine if cold temperatures could promote coexistence between native least chub and introduced western mosquitofish. We used individual scale and population scale experiments to test four hypotheses: 1) colder temperatures would reduce the aggressive behavior …

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 …

The Population Genetics Of The Wood Frog, Rana Sylvatica, Across Its Geographic Range, Tina M. Squire

Theses and Dissertations

This study aimed to determine the level of genetic variation across the continental-wide range of the wood frog, Rana sylvatica. Levels of genetic differentiation between sampled populations were investigated as was the possible locations of glacial refugia for this species. DNA microsatellites were used as the genetic marker. This study found significant genetic differentiation across the geographic range of Rana sylvatica that increased with geographic distance. In addition three likely glacial refugia, Alaska, New York and the southern Appalachians, were identified.

A subset of the populations used in the geographic range study was used to investigate the patterns at a …

The Effectiveness Of Prophylactic Eye Drops On The Reversal Of Uv-Light Induced Cataracts, Contessa Bly Bowman

Theses and Dissertations

Cataracts are a cloudiness of the lens within the eye which obstructs vision. They are found in many species including rats, dogs, and humans. Vision is hindered where this "cloudiness", made of water build up and broken crystalline, proteins take form. Oculvet is an eye medication, used by veterinarians, containing carnosine as its active ingredient. Topical application of carnosine is reported to be an effective treatment for the prevention and removal of pre-existing cataracts. For this experiment, Sprague- Dawley rats were anesthetized and exposed to ultraviolet radiation, UVB and UVC. They were divided into four groups (n = 32), three …

Protein Coevolution And Coadaptation In The Vertebrate Bc1 Complex, Kimberly Kay Baer

Theses and Dissertations

The cytochrome bc1 complex of the mitochondrial electron transport chain accomplishes the enzymatic reaction known as the modified Q-cycle. In the Q-cycle the bc1 complex transports protons from the matrix to the intermembrane space of the mitochondria, creating the proton gradient used to make ATP. The energy to move these protons is obtained by shuttling electrons from the coenzyme ubiquinol (QH2) to coenzyme ubiquinone (Q) and the mobile cytochrome c. This well studied complex is ideal for examining molecular adaptation because it consists of ten different subunits, it functions as a dimer, and it includes at least five different active …

The Origins, Evolution, And Phylogeny Of The Praying Mantises (Dictyoptera: Mantodea), Gavin John Svenson

Theses and Dissertations

The relatively small insect order Mantodea (praying mantises) is comprised of approximately 2,366 described species distributed in 436 genera. Members of the group occupy diverse habitats and are distributed across the globe, though their greatest numbers and diversity are concentrated primarily in the tropics. Though continental endemism is common, many groups have a broad global distribution. An immense diversity of morphology is exhibited across the order with adult mantises ranging in size from 2cm to ~25cm, and appearing like a dead leaf, a piece of quartz rock, or a blade of grass. The diversification and specialization of mantises in ecologically …

Bioassessment And The Partitioning Of Community Composition And Diversity Across Spatial Scales In Wetlands Of The Bonneville Basin, Mary Jane Keleher

Theses and Dissertations

The Bonneville Basin encompasses an area that was covered by ancient Lake Bonneville and which today lies within the Great Basin province. The Bonneville Basin is distinguished geologically by its characteristic parallel north-south mountain ranges that are separated by broad, alluviated desert basins and valleys. Benches and other shoreline features of ancient Lake Bonneville prominently mark the steep, gravelly slopes of these ranges. Numerous artesian desert springs are present at the base of the mountains and in the valley floors that form various sizes of both isolated wetlands and wetland complexes. Many these wetlands are some of the most unique …

Fresh Water Ecology Unit For Secondary Education Science Courses, Eric L. Hyer

Theses and Dissertations

Science means “to know", a process for gaining knowledge and an understanding of the natural world. Students need to be involved in active learning. In other words, they must do science, not just hear about it. Good science encourages students to gain knowledge by doing science: observing, questioning, exploring, making and testing hypotheses, comparing predictions, evaluating data, and communicating conclusions. This unit plan is designed to incorporate the components of fresh water, ecology, water quality, and a class-wide science project. Each lesson addresses selected standards from the state core curriculum and has specific objectives that are tied to the learning …

The Effect Of 1,25-Dihydroxy Vitamin D3 On At1 Cell Receptor Expression In Human Iliac Artery Endothelial Cells (Hiaec), Jenny Thomas

Theses and Dissertations

The renin-angiotensin system (RAS) plays an important part in homeostasis through angiotensin IPs role as a vasoconstrictor. Defects in the renin angiotensin system can lead to hypertension, heart attack, and stroke (Weir, 1999). Studies have shown an inverse relationship between Vitamin D3 and blood pressure (Li et al., 2002). While studies have been performed on vitamin D's effect on renin expression, little is known about vitamin D's effect on the angiotensin II high-affinity type 1 (ATi) receptor. The hypothesis for this study was that human iliac artery endothelial cells (HIAEC) supplemented with 1,25-dihydroxy vitamin D3 will express less AT] receptor …

A Scent-Station Survey Of Medium-Size Mammals On The Callaway Preserve, Harris County, Georgia, Anna-Maria Giacobello

Theses and Dissertations

The objective of this project was to determine the relative abundance of medium- sized mammals on the Callaway Preserve in Harris County, Georgia, using the scent- station technique, to determine species preference in regard to habitat, to compare relative abundance of species in regard to habitat, and to compare habitats in terms of the species present. Thirty-six scent-stations were established on the property and monitored to observe the presence of coyotes, raccoons, armadillos, foxes, opossums, and skunks. Of the total number of visits to the scent-stations, 36.36 % were coyotes, 18.18% were foxes 22.73% were armadillos, and 22.73% were raccoons. …

Corticular Photosynthetic Dynamics For A Coastal Evergreen Shrub: Myrica Cerifera, Jaclyn K. Vick

Theses and Dissertations

I quantified seasonal variations in corticular photosynthesis in 1st through 5th order branches of Myrica cerifera L. (Myricaceae) in order to determine whether corticular photosynthesis contributes to whole plant carbon gain by reducing respirational CO2 loss. Maximum % refixation was 110 ± 39 % of CO2 efflux in the dark (Rd) in 1st order branches during winter, minimum was 18 ± 3 % in 5th order branches during summer. Variations in % refixation paralleled changes in photosynthetically active radiation (PAR). As light attenuated with increasing branch order % refixation decreased. Increased PAR in the winter due to a more sparse …

Interleukin-10 Suppresses Mast Cell Ige Receptor Expression And Signaling In Vitro And In Vivo, Sarah B. Kennedy

Theses and Dissertations

Background: Mast cells are known for their role in allergy, asthma, and systemic anaphylaxis, and have been shown to play a role in inflammatory disease. Interleukin-10 can regulate inflammatory responses both in vitro and in vivo, and may be a natural regulator of mast cell activation.Objective: To examine Interleukin-10 mediated regulation of FcεRI expression and related downstream signaling molecules, and to determine how this affects mast cell function in vitro and in vivo.Methods: Mast cell FcεRI expression was evaluated with and without IL-10 treatment in human lung and skin mast cells, and on peritoneal mast cells from mice overexpressing IL-10 …

Spatial And Temporal Patterns Of Anadromous Fish Passage At Boshers Dam Vertical Slot Fishway On The James River, Richmond, Virginia, Matthew Thomas Fisher

Theses and Dissertations

Boshers dam vertical slot fishway, James River, Virginia, U.S.A., opened in 1999 and restored connectivity to 543.3 km of spawning habitat for anadromous fish. The fishway also allowed local movement of resident species. Video observation from 2001-2005 was used to evaluate environmental predictors of American shad (Alosa sapidissima) and sea lamprey (Petromyzon marinus) passage. The ecological effects of restoring connectivity to upstream habitat for gizzard shad (Dorosoma cepedianum) and blue catfish (Ictalurus furcatus) are also discussed. Regression analysis determined that the best predictor of increased daytime American shad passage is higher water temperatures and discharge and for increased daytime sea …

A Comparison Of The Pectoral Spines In Virginia Catfishes, Amanda Dawn Duvall

Theses and Dissertations

Catfish pectoral spines are an anti-predator defense mechanism. They can be bound or locked, making the fish harder to swallow, or used to produce distress calls by rubbing ridges on the dorsal process against a channel in the wall of the pectoral girdle. Growth of the pectoral spine and girdle were examined in relation to fish size within and across species that occur throughout central and eastern Virginia. These included blue catfish (Ictalurus furcatus), channel catfish (Ictalurus punctatus), white catfish (Ameiurus catus), brown bullheads (Ameiurus nebulosus), yellow bullheads (Ameiurus natalis), flathead catfish (Pylodictis olivaris), margined madtom (Noturus insignis), and tadpole …

Evolution In Neotropical Herpetofauna: Species Boundaries In High Andean Frogs And Evolutionary Genetics In The Lava Lizard Genus Microlophus (Squamata: Tropiduridae): A History Of Colonization And Dispersal, Edgar Benavides

Theses and Dissertations

In this collection of papers I have summarized my investigations into the field of evolutionary genetics and more specifically into patterns of biodiversity and evolutionary processes. The lizards (and frogs) studied here share common features in that they are largely present in unique environments, which are also regions that are biologically understudied. Most of these taxa show high degrees of endemism, interesting natural history characteristics, and each group manifests distinctive adaptations of general evolutionary interest. My work in the genus Telmatobius has been a progressive approach that began in my MS program, and it first focused on alpha taxonomy, morphological …

Genetic Considerations For The Conservation And Management Of Yellowstone Cutthroat Trout (Oncorhynchus Clarkii Bouvieri) In Yellowstone National Park, David J. Janetski

Theses and Dissertations

A key component to conservation is an accurate understanding of genetic subdivision within a species. Despite their ecological and economic importance, relatively little is understood about the genetic structuring of Yellowstone cutthroat trout in Yellowstone National Park. Here, we use traditional (Fst, Rst, Nm, and AMOVA) and modern (Bayesian assignment tests, coalescent theory, and nested clade analysis) analytical approaches to describe the population genetic subdivision of cutthroat trout spawning populations in Yellowstone Lake and to identify genetically distinct population segments throughout Yellowstone National Park. Evidence for restricted gene flow between spawning populations within Yellowstone Lake was detected using nested clade …

Phylogeographic Analyses Of Obligate And Facultative Cave Crayfish Species On The Cumberland Plateau Of The Southern Appalachians, Jennifer Elizabeth Buhay

Theses and Dissertations

Cave systems and their unique biota are widely viewed as highly endangered, yet very little is known about basic life history, ecology, distributions, habitat requirements, and evolutionary relationships of subterranean species. The crux of the problem in cave studies is the assumption that traditionally defined morpho-species represent distinct evolutionary lineages. Convergence is exhibited in the morphologies of many animal groups, vertebrate and invertebrate, which leads to confusion in diagnosing species' boundaries, geographic distributions, gene flow routes, and imperilment. This dissertation research includes phylogeographic analyses of freshwater cave-dwelling crayfishes in the Southern Appalachians, a global hotspot of subterranean biodiversity. By examining …

Delimitating Species Boundaries Within The Liomys Pictus- Spectabilis Complex (Rodentia: Heteromyidae), Victoria L. Vance

Theses and Dissertations

Previous studies based on morphological, allozymic and mitochondrial sequence data have indicated that Liomys pictus is paraplyletic relative to L. spectabilis. The purpose of this study was to determine the species boundaries that exist within this complex. I estimated phylogenetic relationships within this complex using sequence data from 1,140 bp of the mitochondrial DNA cytochrome b gene and two nuclear introns from engrailed protein (190 bp) and myosin heavy chain (254 bp) genes for approximately 712 individuals representing 82 localities across the range of L. pictus and L. spectabilis. Maximum parsimony, maximum likelihood, and Bayesian analyses suggest that there are …

The Dogma Of The 30 Meter Riparian Buffer: The Case Of The Boreal Toad (Bufo Boreas Boreas), Michael C. Goates

Theses and Dissertations

We tested the adequacy of standard 30 m riparian buffers for semi-aquatic vertebrate species, using the boreal toad (Bufo boreas boreas) as an example. We monitored toad populations in south-central Utah using radio telemetry during the summers of 2003 and 2004. We found 30 m buffers inadequate for protecting boreal toads and suggest this is likely true for other species as well. Managers must consider several factors when constructing buffers: (1) Buffer requirements may vary by time of year. While we located toads most often in wet habitats, toads commonly utilized upland habitats in late summer, occasionally at distances greater …