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Effects Of A Chronic Increase In Plasma Corticosterone On The Brooding Behavior Of The Prairie Skink, Plestiodon Septentrionalis , Alexander James Anton

Student Work

The effects of chronic corticosterone (CORT) increases on the maternal behavior of the Prairie Skink, Plestiodon septentrionalis were studied in the laboratory during the summer of 2012. It was hypothesized that chronic increases in plasma CORT would result in decreased maternal effort and higher egg mortality, with similar results to analogous studies in birds. Plasma CORT was elevated using a non-invasive, exogenous treatment and behaviors were observed using video recordings. CORT treatments significantly reduced the amount of time spent tightly coiled around eggs in experimental individuals, and significantly decreased the amount of time experimental females spend in contact with their …

Resistance Is Futile: The Bacteriocin Model For Addressing The Antibiotic Resistance Challenge, Margaret A. Riley, Sandra M. Robinson, Christopher M. Roy, Morgan Dennis, Vivian Liu, Robert Dorit

Biological Sciences: Faculty Publications

Pathogenic bacteria resistant to many or all antibiotics already exist. With the decline in microbiological research at pharmaceutical companies, the high rate at which resistance has evolved and spread has demanded a novel approach to addressing this critical human health issue. In the present paper, we propose a new paradigm in antibiotic discovery and development, one that applies ecological and evolutionary theory to design antimicrobial drugs that are more difficult and/or more costly to resist. In essence, we propose to simply adopt the strategies invented and applied by bacteria for hundreds of millions of years. Our research focuses on bacteriocins, …

Molecular Phylogeny Of Microhylid Frogs (Anura: Microhylidae) With Emphasis On Relationships Among New World Genera, Rafael O. De Sá, Jeffrey W. Streicher, Relebohile Sekonyela, Mauricio C. Forlani, Simon P. Loader, Eli Greenbaum, Stephen Richards, Célio F.B. Haddad

Biology Faculty Publications

Background: Over the last ten years we have seen great efforts focused on revising amphibian systematics. Phylogenetic reconstructions derived from DNA sequence data have played a central role in these revisionary studies but have typically under-sampled the diverse frog family Microhylidae. Here, we present a detailed phylogenetic study focused on expanding previous hypotheses of relationships within this cosmopolitan family. Specifically, we placed an emphasis on assessing relationships among New World genera and those taxa with uncertain phylogenetic affinities (i.e., incertae sedis).

Results: One mitochondrial and three nuclear genes (about 2.8 kb) were sequenced to assess phylogenetic relationships. We utilized an …

Tet1: A Unique Dna Demethylase For Maintenance Of Dna Methylation Pattern, Chunlei Jin

Dissertations and Theses (Open Access)

DNA methylation at the C5 position of cytosine (5-methylcytosine, 5mC) is a crucial epigenetic modification of the genome and has been implicated in numerous cellular processes in mammals, including embryonic development, transcription, X chromosome inactivation, genomic imprinting and chromatin structure. Like histone modifications, DNA methylation is also dynamic and reversible. However, in contrast to well defined DNA methyltransferases, the enzymes responsible for erasing DNA methylation still remain to be studied. The ten-eleven translocation family proteins (TET1/2/3) were recently identified as Fe(II)/2-oxoglutarate (2OG)-dependent 5mC dioxygenases, which consecutively convert 5mC into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine and 5-carboxylcytosine both in vitro and in mammalian …

Gene Duplication And The Evolution Of Hemoglobin Isoform Differentiation In Birds, Michael T. Grispo

School of Biological Sciences: Dissertations, Theses, and Student Research

The majority of bird species co-express two functionally distinct hemoglobin (Hb) isoforms in definitive erythrocytes: HbA (the major adult Hb isoform, with α-chain subunits encoded by the α^A-globin gene) and HbD (the minor adult Hb isoform, with α-chain subunits encoded by the α^D-globin gene). The α^D-globin gene originated via tandem duplication of an embryonic α-like globin gene in the stem lineage of tetrapod vertebrates, which suggests the possibility that functional differentiation between the HbA and HbD isoforms may be attributable to a retained ancestral character state in HbD that harkens back to a primordial, …

Biogenic Amine Levels Correlate With Time Of Day, Age, Light Cycle, And Aggressive State In The Flesh Fly, Sarcophaga Crassipalpis, Veronica L. Fregoso

Electronic Theses and Dissertations

The biogenic amines serotonin (5HT), dopamine (DA), and octopamine (OA) have been indicated in the regulation of behaviors, including aggression. The flesh fly, Sarcophaga crassipalpis, was used to investigate ontogenetic and circadian changes in amines and aggression. Heads of male flies were analyzed for amine content using high performance liquid chromatography with electrochemical detection (HPLC-ECD) at 3 time points on each of 4 consecutive days in 2 light cycles, 12:12 LD and 15:9 LD. Both DA and OA levels decreased with age. Light-cycle dependent differences were observed for all amines in overall levels and patterns of change throughout the …

Laboratory And Field Performance Of The Biosand Point Of Use Water Filtration System In The Artibonite Valley, Haiti, Andrew John Sisson

Masters Theses

The research presented here is summary two years of studying the Biosand filter (BSF) both in Haiti during March 2011 and in the laboratory. In Chapter 2, we examined the long term use and sustainability 55 BSF systems near Deschapelles, Haiti and 47% were found to be no longer in use. Interviews with BSF owners revealed problems related to intermittent filter use. A review of 17 BSF field studies also was included to compare and substantiate observations made in Haiti. Together, previous field studies and our observations point toward the importance of providing culturally appropriate technologies and education materials explaining …

A Genetic, Transgenic, And Transcriptomic Analysis Of Larval Salivary Gland Physiology In Drosophila Melanogaster, Elana A. Paladino

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cholesterol is the precursor to a unique class of lipophilic signaling molecules called steroid hormones that initiate the development of sexual characteristics, reactions to stress, and maintenance of metabolism, among many other functions. Although much progress has been made in understanding the function of these signaling hormones, we do not fully understand how a single steroid can cause many distinct, tissue-specific responses. Drosophila melanogaster is an effective model for understanding steroid hormone action because of its simplicity. The steroid molting hormone 20-hydroxyecdysone (hereafter, 20E) is the primary active steroid in Drosophila and mediates not only larval molts and the emergence …

Conservation Genetics Of A Spotted Salamander (Ambystoma Maculatum (Shaw 1802)) Local Population In Southeast Tennessee, Daniel Scott Armstrong

Masters Theses and Doctoral Dissertations

Currently there is a worldwide amphibian decline with numerous causes. Because of this, it is important to understand how genetic variation in local amphibian populations is affected by disturbance. The goal of this study was to assess the genetic impacts of past chemical and ammunition storage and present industrialization on a local population of Ambystoma maculatum (Shaw 1802) using thirteen microsatellite markers. Most loci exhibited no loss of heterozygosity but the low effective population size may indicate vulnerability to future declines. No population substructure or sex-biased dispersal was detected. Possible explanations for the reduction in genetic diversity at four loci …

The Rise And Fall Of Kin Structure In The Neotropical, Family-Living Buff-Breasted Wren (Cantorchilus Leucotis) In Gamboa, Panama, Sarah C. Alessi

Masters Theses

Family-living species provide an exciting model to examine how natal dispersal and kin structure influence genetic structuring within local populations. Juvenile buff-breasted wrens (Cantorchilus leucotis) of both sexes delay dispersal and exhibit short-distance natal dispersal, which should lead to kin-structured populations in which relatives of both sexes occupy neighboring territories. Blood samples collected from juvenile and adult wrens in Gamboa, Panama were analyzed using microsatellite markers to determine whether related individuals are spatially clustered on neighboring territories, spatial clusters of relatives change over time, and if kin structure is sex-specific. Global and local spatial autocorrelation analyses detected genetic …

Community Structure And Ecological Specialization In Plant-Ant Interactions, Paola Barriga

Graduate Theses and Dissertations

Positive associations among species have contributed to the maintenance of biodiversity. These interactions are typically studied in pairwise fashion where two interacting organisms are the focus. This dissertation uses network theory to analyze positive plant-ant associations in three Neotropical forests. Obligate plant-ant mutualisms were used, where plants host the ants in domatia and provide food bodies while the ants protect the plants and can feed them. A network approach was used to depict all obligate plant-ant interactions within a community. The main questions asked at the community level were: 1) Do network structure and levels of specialization change geographically and, …

Energy Development And Conservation Of Sympatric Wildlife: New Approaches To Meet Growing Challenges, William Christian Dunn

Biology ETDs

Conflicts between energy development and conservation of sympatric wildlife are becoming more acute as demand for energy increases. Resolving these conflicts is complex-- solutions must address the role of location, scale, and connectivity in persistence of populations. In Chapter 1, I use the MaxEnt species distribution model and pertinent climate variables to predict the natural distribution of the Lesser Prairie Chicken (LPC) (Tympanuchus pallidicinctus), a prairie grouse adversely affected by habitat loss from energy development. Within the geographic range of LPC, precipitation was strongly associated with its distribution in the north, whereas temperature was strongly associated with its distribution in …

Effects Of Climate Change Upon Birds In The Mojave And Sonoran Deserts, Harinamsimran Kaur Khalsa

Biology ETDs

Climate change has increasingly become an area of concern in relation to ecological communities. In this study, climatic signals were investigated to determine whether bird diversity indices in the Breeding Conservation Region (BCR) of the Mojave and Sonoran Deserts were related (1) to the oceanic/atmospheric systems El Nino Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and/or the Atlantic Multidecadal Oscillation (AMO); (2) to regional moisture influences determined by the Palmer Drought Severity Index (PDSI); and (3) to local precipitation and temperature. Specifically, an examination was conducted to determine the relationship between climatic variables for thirteen bird species, total abundance …

Genetic Diversity, Local Differentiation, And Adaptive Evolution In Introduced Populations Of The Invasive Plant Isatis Tinctoria L. (Brassicaceae), Heather L. Simpson

Biology ETDs

Populations of invasive species are often characterized as genetically depauperate, an inherent consequence of the colonization process. It has also been suggested that species that are able to avoid these reductions in genetic diversity may be better able to adapt to their introduced range. Evolutionary change can play an important role in the invasion process if novel selective pressures drive adaptive evolution. Species that are able to avoid reductions in genetic diversity associated with colonization may be better able to adapt to their introduced range. To better understand the genetic processes following invasion, introduced populations of the invasive mustard, Isatis …

Mir-786 Regulation Of A Fatty-Acid Elongase Contributes To Rhythmic Calcium-Wave Initiation In C. Elegans, Benedict J. Kemp, Erik Allman, Lois Immerman, Megan Mohnen, Maureen A. Peters, Keith Nerhke, Allison L. Abbott

Biological Sciences Faculty Research and Publications

Background: Rhythmic behaviors are ubiquitous phenomena in animals. In C. elegans, defecation is an ultradian rhythmic behavior: every ∼50 s a calcium wave initiating in the posterior intestinal cells triggers the defecation motor program that comprises three sequential muscle contractions. Oscillatory calcium signaling is central to the periodicity of defecation. The posteriormost intestinal cells function as the pacemaker for this rhythmic behavior, although it is unclear how the supremacy of these cells for calcium-wave initiation is controlled.

Results: We describe how the loss of the mir-240/786 microRNA cluster, which results in arrhythmic defecation, causes ectopic intestinal calcium-wave initiation. mir-240/786 expression …

Fungal Biofilm Colonization And Succession On Artificial Reefs In The North-Central Gulf Of Mexico, Amy Leigh Salamone

Master's Theses

This study represents the first characterization of natural mixed-species fungal biofilm communities on artificial reefs in the marine environment. Previous fungal biofilm studies have failed to observe the naturally-occurring biodiversity in coastal areas, which comprise the most utilized zone of the marine environment. Artificial reefs can increase fishing yields, amplify oyster habitats, contribute to shoreline stabilization, promote good water quality, and deter pollution. Proper management practices of artificial reefs require knowledge of the colonization of these new habitats by marine organisms and their subsequent succession. Fungi, along with bacteria, archaea, protists, algae, and diatoms, quickly form a complex biofilm on …

Modulation Of The Host Response To Tacaribe Arenavirus Infection In Ag129 Mice By My-24, Eric Sefing

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

MY-24 is a new antiviral compound recently shown to protect immunocompromised mice from lethal challenge with Tacaribe virus (TCRV). Tacaribe virus is incapable of causing disease to humans, but is closely related to the highly pathogenic New World arenaviruses that cause often-fatal viral hemorrhagic fever syndromes. Remarkably, MY-24 prevents mortality without reducing virus burden in the circulation or tissues. To investigate the mechanism by which MY-24 protects AG129 mice against Tacaribe virus infection, we first characterized the natural history of disease in the model with an emphasis on host immune response and blood vessel function to establish the best times …

Localizing Brain Regions Associated With Female Mate Preference Behavior In A Swordtail, Ryan Y. Wong, Mary E. Ramsey, Molly E. Cummings

Biology Faculty Publications

Female mate choice behavior is a critical component of sexual selection, yet identifying the neural basis of this behavior is largely unresolved. Previous studies have implicated sensory processing and hypothalamic brain regions during female mate choice and there is a conserved network of brain regions (Social Behavior Network, SBN) that underlies sexual behaviors. However, we are only beginning to understand the role this network has in pre-copulatory female mate choice. Using in situ hybridization, we identify brain regions associated with mate preference in female Xiphophorus nigrensis, a swordtail species with a female choice mating system. We measure gene expression in …

Late Embryogenesis Abundant Proteins Protect Human Hepatoma Cells During Acute Desiccation, Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael A. Menze, Mehmet Toner, Steven C. Hand

Faculty Research & Creative Activity

Expression of late embryogenesis abundant (LEA) proteins is highly correlated with desiccation tolerance in anhydrobiotic animals, selected land plants, and bacteria. Genes encoding two LEA proteins, one localized to the cytoplasm/nucleus (AfrLEA2) and one targeted to mitochondria (AfrLEA3m), were stably transfected into human HepG2 cells. A trehalose transporterwas used for intracellular loading of this disaccharide. Cellswere rapidly and uniformly desiccated to low water content (<0.12 g H2O/g dry weight) with a recently developed spin-drying technique. Immediately on rehydration, control cells without LEA proteins or trehalose exhibited 0% membrane integrity, comparedwith 98% in cells loaded with trehalose and expressing AfrLEA2 or AfrLEA3m; surprisingly, AfrLEA3m without trehalose conferred 94% protection. Cell proliferation across 7 d showed an 18-fold increase for cells dried with AfrLEA3m and trehalose, compared with 27-fold for nondried controls. LEA proteins dramatically enhance desiccation tolerance in mammalian cells and offer the opportunity for engineering biostability in the dried state.

Late Embryogenesis Abundant Proteins Protect Human Hepatoma Cells During Acute Desiccation., Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael Menze, Mehmet Toner, Steven Hand

Faculty and Staff Scholarship

Expression of late embryogenesis abundant (LEA) proteins is highly correlated with desiccation tolerance in anhydrobiotic animals, selected land plants, and bacteria. Genes encoding two LEA proteins, one localized to the cytoplasm/nucleus (AfrLEA2) and one targeted to mitochondria (AfrLEA3m), were stably transfected into human HepG2 cells. A trehalose transporterwas used for intracellular loading of this disaccharide. Cellswere rapidly and uniformly desiccated to low water content (< 0.12 g H2O/g dry weight) with a recently developed spin-drying technique. Immediately on rehydration, control cells without LEA proteins or trehalose exhibited 0% membrane integrity, comparedwith 98% in cells loaded with trehalose and expressing AfrLEA2 or AfrLEA3m; surprisingly, AfrLEA3m without trehalose conferred 94% protection. Cell proliferation across 7 d showed an 18-fold increase for cells dried with AfrLEA3m and trehalose, compared with 27-fold for nondried controls. LEA proteins dramatically enhance desiccation tolerance in mammalian cells and offer the opportunity for engineering biostability in the dried state.

Strike Mechanics Of An Ambush Predator: The Spearing Mantis Shrimp, M. Devries, E. Murphy, S. Patek

Faculty Publications, Biological Sciences

Ambush predation is characterized by an animal scanning the environment from a concealed position and then rapidly executing a surprise attack. Mantis shrimp (Stomatopoda) consist of both ambush predators (‘spearers’) and foragers (‘smashers’). Spearers hide in sandy burrows and capture evasive prey, whereas smashers search for prey away from their burrows and typically hammer hard-shelled, sedentary prey. Here, we examined the kinematics, morphology and field behavior of spearing mantis shrimp and compared them with previously studied smashers. Using two species with dramatically different adult sizes, we found that strikes produced by the diminutive species, Alachosquilla vicina, were faster (mean peak …

Na+/K+-Atpase Isoform Regulation In Three-Spine Stickleback (Gasterosteus Aculeatus) During Salinity Acclimation, Shelby Judd

College of Science and Health Theses and Dissertations

Most marine and all freshwater fishes regulate the ionic and osmotic composition of their extracellular fluids different from the outside environment. The gills play a prominent osmoregulatory role in maintaining whole body ion and water balance in fish living in both freshwater and saltwater environments. The ability of the gill to regulate salts is dependent on the action of the Na⁺/K⁺-ATPase. When euryhaline fishes, fishes able to tolerate changes in external salinity, experience changes in environmental salinity, they alter their gill physiology and Na⁺/K⁺-ATPase activity to handle changing osmotic and ionic stresses. …

Toward The Beginning Of Time: Circadian Rhythms In Metabolism Precede Rhythms In Clock Gene Expression In Mouse Embryonic Stem Cells, Jiffin K. Paulose, Edmund B. Rucker Iii, Vincent M. Cassone

Biology Faculty Publications

The appearance, progression, and potential role for circadian rhythms during early development have previously focused mainly on the suprachiasmatic nucleus (SCN) and peri- and postnatal expression of canonical clock genes. More recently, gene expression studies in embryonic stem cells have shown that some clock genes are expressed in undifferentiated cells; however rhythmicity was only established when cells are directed toward a neural fate. These studies also concluded that a functional clock is not present in ESCs, based solely on their gene expression. The null hypothesis underlying the present study is that embryonic stem cells become rhythmic in both clock gene …

Blt1 And Mid1 Provide Overlapping Membrane Anchors To Position The Division Plane In Fission Yeast, Merce Guzman-Vendrell, Suzanne Baldissard, Maria Almonacid, Adeline Mayeux, Anne Paoletti, James B. Moseley

Dartmouth Scholarship

Spatial control of cytokinesis is essential for proper cell division. The molecular mechanisms that anchor the dynamic assembly and constriction of the cytokinetic ring at the plasma membrane remain unclear. In the fission yeast Schizosaccharomyces pombe, the cytokinetic ring is assembled in the cell middle from cortical node precursors that are positioned by the anillin-like protein Mid1. During mitotic entry, cortical nodes mature and then compact into a contractile ring positioned in the cell middle. The molecular link between Mid1 and medial cortical nodes remains poorly defined. Here we show that Blt1, a previously enig- matic cortical node protein, promotes …

Inhibition Of Microrna-302 (Mir-302) By Bone Morphogenetic Protein 4 (Bmp4) Facilitates The Bmp Signaling Pathway, Hara Kang, Justin Louie, Alexandra Weisman, Jessica Sheu-Gruttadauria, Brandi N. Davis-Dusenbery, Giorgio Lagna, Akiko Hata

Biology

The signaling pathway mediated by BMPs plays an essential role during development as well as the maintenance of homeostasis in adult. Aberrant activation or inactivation of BMP signaling can lead to developmental defects and various human disorders. To fine-tune its activity, BMP signaling is regulated both positively and negatively by extrinsic and intrinsic regulatory factors that modulate binding of ligand to the receptors, and the activity of receptors and their dedicated signal transducers, the Smad proteins. Upon BMP binding to the receptor complex, Smad proteins translocate to the nucleus and modulate gene expression transcriptionally by directly associating with the promoter …

Ornamental Bill Color Rapidly Signals Changing Condition, M. F. Rosenthal, Troy G. Murphy, N. Darling, K. A. Tarvin

Biology Faculty Research

Ornamental bill color is postulated to function as a condition-dependent signal of individual quality in a variety of taxonomically distant bird families. Most red, orange, and yellow bill colors are derived from carotenoid pigments, and carotenoid deposition in ornamentation may trade off with their use as immunostimulants and antioxidants or with other physiological functions. Several studies have found that bill color changes in response to physiological perturbations, but how quickly such changes can occur remains unclear. We tested the hypothesis that carotenoid-based orange bill color of American goldfinches Spinus tristis responds dynamically to rapid changes in physiological stress and reflects …

Metabolic Preconditioning Of Mammalian Cells: Mimetic Agents For Hypoxia Lack Fidelity In Promoting Phosphorylation Of Pyruvate Dehydrogenase, Apurva Borcar, Michael A. Menze, Mehmet Toner, Steven C. Hand

Faculty Research & Creative Activity

Induction of HIF-1α by oxygen limitation promotes increased phosphorylation and catalytic depression of mitochondrial pyruvate dehydrogenase (PDH) and an enhanced glycolytic poise in cells. Cobalt chloride and desferrioxamine are widely used as mimics for hypoxia because they increase the levels of HIF-1α. We evaluated the ability of these agents to elicit selected physiological responses to hypoxia as a means to metabolically precondition mammalian cells, but without the detrimental effects of hypoxia. We show that, while CoCl2 does increase HIF-1α in a dose-dependent manner, it unexpectedly and strikingly decreases PDH phosphorylation at E1α sites 1, 2, and 3 (Ser293, Ser300, and …

Evidence For An Interaction Of Neuronostatin With The Orphan G Protein-Coupled Receptor, Gpr107, Gina L.C. Yosten, Lauren J. Redlinger, Willis K. Samson

Biological Sciences Faculty Research & Creative Works

Neuronostatin, derived from the somatostatin preprohormone, is a recently described peptide that is produced by several tissues involved in cardiovascular regulation and metabolism, including the hypothalamus. Injection of neuronostatin into the lateral cerebroventricle led to a dose-related increase in mean arterial pressure (MAP) in rats. Any attempt to inhibit the production of neuronostatin would alter somatostatin production as well, making determination of the physiological relevance of the peptide's pharmacologic effects by compromise of production approaches impossible. Therefore, we employed an alternative approach to identify and compromise the production of the neuronostatin receptor. Because neuronostatin was shown to signal via a …

Performance And Scaling Of A Novel Locomotor Structure: Adhesive Capacity Of Climbing Gobiid Fishes, Richard W. Blob, Takashi Maie, Heiko L. Schoenfuss

Publications

Many species of gobiid fishes adhere to surfaces using a sucker formed from fusion of the pelvic fins. Juveniles of many amphidromous species use this pelvic sucker to scale waterfalls during migrations to upstream habitats after an oceanic larval phase. However, adults may still use suckers to re-scale waterfalls if displaced. If attachment force is proportional to sucker area and if growth of the sucker is isometric, then increases in the forces that climbing fish must resist might outpace adhesive capacity, causing climbing performance to decline through ontogeny. To test for such trends, we measured pressure differentials and adhesive suction …

Metabolic Preconditioning Of Mammalian Cells : Mimetic Agents For Hypoxia Lack Fidelity In Promoting Phosphorylation Of Pyruvate Dehydrogenase., Apurva Borcar, Michael Menze, Mehmet Toner, Steven Hand

Faculty and Staff Scholarship

Induction of HIF-1α by oxygen limitation promotes increased phosphorylation and catalytic depression of mitochondrial pyruvate dehydrogenase (PDH) and an enhanced glycolytic poise in cells. Cobalt chloride and desferrioxamine are widely used as mimics for hypoxia because they increase the levels of HIF-1α. We evaluated the ability of these agents to elicit selected physiological responses to hypoxia as a means to metabolically precondition mammalian cells, but without the detrimental effects of hypoxia. We show that, while CoCl2 does increase HIF-1α in a dose-dependent manner, it unexpectedly and strikingly decreases PDH phosphorylation at E1α sites 1, 2, and 3 (Ser293, Ser300, and …