Biology Commons^™

An Inverse Association Between West Nile Virus Serostatus And Avian Malaria Infection Status, Robert Ricklefs, Matthew Ci Medeiros, Tavis K. Anderson, Jenni M. Higashiguchi, Uriel D. Kitron, Edward D. Walker, Jeffrey D. Brawn, Bethany L. Krebs, Marilyn O. Ruiz, Tony L. Goldberg, Gabriel L. Hamer

Robert Ricklefs

Cholinergic Transmission During Nicotine Withdrawal Is Influenced By Age And Pre-Exposure To Nicotine: Implications For Teenage Smoking, Laura O'Dell

Laura Elena O'Dell

Adolescence is a unique period of development characterized by enhanced tobacco use and long-term vulnerability to neurochemical changes produced by adolescent nicotine exposure. In order to understand the underlying mechanisms that contribute to developmental differences in tobacco use, this study compared changes in cholinergic transmission produced by exposure to nicotine and withdrawal from nicotine in rats of different ages, some of which had exposure to nicotine as adolescents. The first study compared extracellular levels of acetylcholine (ACh) in the nucleus accumbens (NAcc) during nicotine withdrawal in adolescent, adult and adult rats that were exposed to nicotine during adolescence. Adolescent (PND …

Insulin-Resistant Rats Display Enhanced Nicotine Reward Following A High-Fat Diet Regimen., Laura O'Dell

Laura Elena O'Dell

Tobacco use among persons displaying type II diabetes exponentially increases negative health consequences and mortality rates. Especially troubling, diabetic persons who smoke display reduced rates of tobacco cessation as compared to non-diabetic smokers. Diabetes is a metabolic syndrome that consists of insulin resistance due to disruptions in insulin signaling. Insulin has been shown to modulate mesolimbic reward circuitry in response to drugs of abuse, such as nicotine. This study utilized the conditioned place preference paradigm (CPP) to examine nicotine reward in a rat model of insulin resistance induced by the consumption of a high-fat diet (HFD). Rats were placed on …

Review: Zinc’S Functional Significance In The Vertebrate Retina, Harris Ripps, Richard L. Chappell

Publications and Research

This review covers a broad range of topics related to the actions of zinc on the cells of the vertebrate retina. Much of this review relies on studies in which zinc was applied exogenously, and therefore the results, albeit highly suggestive, lack physiologic significance. This view stems from the fact that the concentrations of zinc used in these studies may not be encountered under the normal circumstances of life. This caveat is due to the lack of a zinc-specific probe with which to measure the concentrations of Zn2+ that may be released from neurons or act upon them. However, a …

Immune Function And Infection Status Is Related To Migration Distance And Phases Of The Annual Cycle In Song Sparrows (Melospiza Melodia), Tosha R. Kelly

Electronic Thesis and Dissertation Repository

Life history theory predicts animals adjust immune investment based on their risk of encountering familiar and unfamiliar parasites. Although long-distance migrants may encounter a greater diversity of parasites than short-distance migrants, the energetic costs of migration may constrain immune investment. However, few studies have investigated the relationship between migration distance and immunity. I used stable isotope analysis to estimate the wintering latitude, and thus migration distance, of song sparrows (Melospiza melodia). I assessed whether migration distance was related to the incidence of infection with a blood-borne parasite, parasite load, and immune function. The incidence of infection increased with …

The Show Cave Of Diros Vs. Wild Caves Of Peloponnese, Greece - Distribution Patterns Of Cyanobacteria, Vasiliki Lamprinou, Daniel B. Danielidis, Adriani Pantazidou, Alexandra Oikonomou, Athena Economou-Amilli

International Journal of Speleology

The karst cave ‘Vlychada’of Diros, one of the oldest show caves in Peloponnese, sustains extended phototrophic biofilms on various substrata – on rocks inside the cave including speleothems, and especially near the artificial lighting installation (‘Lampenflora’). After a survey of the main abiotic parameters (Photosynthetically Active Radiation -PAR, Temperature -T, Relative Humidity -RH, Carbon Dioxide -CO₂) three clusters of sampling sites were revealed according to Principal Component Analysis (PCA): i) the water gallery section predominately influenced by CO₂, ii) the dry passages influenced by RH and PAR, and iii) the area by the cave exit at …

Elucidation Of The Role Of Auxin-Input Pathways In Auxin Homeostasis., Gretchen Spiess

Dissertations

Auxin is a phytohormone involved in cell elongation and division. Levels of indole-3-acetic acid (IAA), the most abundant auxin, are tightly regulated through biosynthesis, degradation, sequestration, and transport. Sequestration of IAA occurs in reversible processes by adding amino acids, polyol or simple alcohols, or sugars, forming IAA conjugates, or via a two-carbon elongation forming indole-3-butyric acid (IBA). These forms of auxin have decreased activity and are located in multiple organelles. Using a combination of molecular and genetic tools, I examined how these storage forms are working together to contribute to overall IAA levels and IAA response in both the model …

Leaf Mechanical Strength Corresponds To Tissue Water Relations In Twelve Species Of California Ferns, Breahna M. Gillespie, Stephen D. Davis, Jarmila Pittermann

Biology

The dominant vegetation types in southern California’s coastal foothills are chaparral and costal sage scrub. Chaparral shrubs have mechanically strong evergreen leaves whereas coastal sage scrubs bear mechanical weak, facultative deciduous leaves. What about the ferns that live in the understory of these vegetation types, especially considering their adaptations to a summer dry, Mediterranean-type climate? We tested the hypothesis that some fern leaves are stronger than others and mechanically strong leaves are associated with greater dehydration tolerance. Twelve fern species were examined. Tissue water relations were assessed via pressure volume curves using Scholander-Hammel pressure chambers. We estimated osmotic potential at …

What Can We Learn From Confusing Olivella Columellaris And O. Semistriata (Olivellidae, Gastropoda), Two Key Species In Panamic Sandy Beach Ecosystems?, Alison I. Troost, Samantha D. Rupert, Ariel Z. Cyrus, Frank V. Paladino, Benjamin F. Dattilo, Winfried S. Peters

Benjamin F. Dattilo

Abstract: Olivella columellaris (Sowerby 1825) and O. semistriata (Gray 1839) are suspension-feeding, swash-surfing snails on tropical sandy beaches of the east Pacific. While they often are the numerically dominant macrofaunal element in their habitats, their biology is poorly understood; the two species actually have been confused in all of the few publications that address their ecology. Frequent misidentifications in publications and collections contributed also to an overestimation of the geographic overlap of the two species. To provide a sound taxonomic basis for further functional, ecological, and evolutionary investigations, we evaluated the validity of diagnostic traits in wild populations and museum …

Response Of Beta Diversity To Pulses Of Ordovician-Silurian Mass Extinction, Simon A.F. Darroch, Peter J. Wagner

School of Biological Sciences: Faculty Publications

Ecologists are increasingly using the fossil record of mass extinction to build predictive models for the ongoing biodiversity crisis. During mass extinctions, major depletions in global (i.e., gamma) diversity may reflect decrease in alpha diversity (i.e., local assemblages support fewer taxa), and/or decrease in beta diversity (such that similar pools of taxa are common to a greater number of local areas). Contrasting the effects of extinction on alpha and beta diversity is therefore central to understanding how global richness becomes depleted over these critical events. Here we investigate the spatial effects of mass extinction by examining changes in alpha, beta, …

Anthocyanin Characterization, Total Phenolic Quantification And Antioxidant Features Of Some Chilean Edible Berry Extracts, Anghel Brito, Carlos Areche, Beatriz Sepúlveda, Edward J. Kennelly, Mario J. Simirgiotis

Publications and Research

The anthocyanin composition and HPLC fingerprints of six small berries endemic of the VIII region of Chile were investigated using high resolution mass analysis for the first time (HR-ToF-ESI-MS). The antioxidant features of the six endemic species were compared, including a variety of blueberries which is one of the most commercially significant berry crops in Chile. The anthocyanin fingerprints obtained for the fruits were compared and correlated with the antioxidant features measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics, flavonoids and anthocyanins …

Relationship Between Dehydration Tolerance Of California Ferns And The Mechanical Strength Of Their Stipes, Helen I. Holmlund, Stephen D. Davis

Biology

In recent years, experts in plant physiology have begun to explore the functional traits of ferns, especially in regards to their tissue-water relations. However, to our knowledge, no scientist had yet examined the relationship between fern biomechanics and physiology. We examined the mechanical properties of fern stipes (stems) and attempted to relate those properties to ecological and physiological traits. Based on our knowledge of fern anatomy, we hypothesized that stipe mechanical strength would not correlate with water-stress resistance as it does in seed-bearing plants.

We assessed mechanical strength using Modulus of Elasticity (MOE) and tissue-water relations using pressure-volume curves. Water-stress …

Human Common Fragile Site Fra16d Flexibility Peak Is Not A Strong Mitotic: Recombination Hotspot In Saccharomyces Cerevisiae, Katina G. Kapellas

Master's Theses and Doctoral Dissertations

Common fragile sites (CFS) are areas of the genome that tend to break when DNA replication is stressed or partially inhibited. Breaks at CFS can lead to gene deletions and amplifications that can result in the genesis of cancer cells. There is controversy about the mechanism of CFS instability. This study examines whether an AT-rich sequence called a flexibility peak from FRA16D can induce mitotic recombination events that lead to loss of heterozygosity (LOH) on chromosome III in Saccharomyces cerevisiae. Two experimental yeast strains containing flexibility peak Flex1-(AT)15 from FRA16D were compared to a control strain lacking the Flex1 …

Phenotypic Analysis Of The Regulatory Role Of The Leucine-Responsive Regulatory Protein (Lrppa) In Pseudomonas Aeruginosa, Stephanie D. Larson

Master of Science in Integrative Biology Theses

Nutrient acquisition is critical to survival and infection by the opportunistic bacterium Pseudomonas aeruginosa. This pathogen expresses a number of virulence factors that are a part of the starvation response and are important in host-pathogen interactions. Additionally, P. aeruginosa is resistant to a large number of antibiotics and has become difficult to treat once it has colonized a tissue. New pharmaceutical treatments are sought while the metabolism of this organism must be fully understood to select new targets for therapy. The leucine- responsive regulatory protein (Lrp) could be a promising target for treatment. The ortholog in Escherichia coli is …

Collective Behaviour Without Collective Order In Wild Swarms Of Midges, Alessandro Attanasi, Andrea Cavagna, Lorenzo Del Castello, Irene Giardina, Stefania Melillo, Leonardo Parisi, Oliver Pohl, Bruno Rossaro, Edward Shen, Edmondo Silvestri, Massimilano Viale

Publications and Research

Collective behaviour is a widespread phenomenon in biology, cutting through a huge span of scales, from cell colonies up to bird flocks and fish schools. The most prominent trait of collective behaviour is the emergence of global order: individuals synchronize their states, giving the stunning impression that the group behaves as one. In many biological systems, though, it is unclear whether global order is present. A paradigmatic case is that of insect swarms, whose erratic movements seem to suggest that group formation is a mere epiphenomenon of the independent interaction of each individual with an external landmark. In these cases, …

Metagenomic Identification Of A Novel Salt Tolerance Gene From The Human Gut Microbiome Which Encodes A Membrane Protein With Homology To A Brp/Blh-Family Beta-Carotene 15,15'-Monooxygenase, Eamonn P. Culligan, Roy D. Sleator, Julian R. Marchesi, Colin Hill

Department of Biological Sciences Publications

The human gut microbiome consists of at least 3 million non-redundant genes, 150 times that of the core human genome. Herein, we report the identification and characterisation of a novel stress tolerance gene from the human gut metagenome. The locus, assigned brpA, encodes a membrane protein with homology to a brp/blh-family β-carotene monooxygenase. Cloning and heterologous expression of brpA in Escherichia coli confers a significant salt tolerance phenotype. Furthermore, when cultured in the presence of exogenous β-carotene, cell pellets adopt a red/orange pigmentation indicating the incorporation of carotenoids in the cell membrane.

Metagenomic Identification Of A Novel Salt Tolerance Gene From The Human Gut Microbiome Which Encodes A Membrane Protein With Homology To A Brp/Blh-Family Beta-Carotene 15,15'-Monooxygenase, Roy D. Sleator, Et. Al.

Department of Biological Sciences Publications

The human gut microbiome consists of at least 3 million non-redundant genes, 150 times that of the core human genome. Herein, we report the identification and characterisation of a novel stress tolerance gene from the human gut metagenome. The locus, assigned brpA, encodes a membrane protein with homology to a brp/blh-family β-carotene monooxygenase. Cloning and heterologous expression of brpA in Escherichia coli confers a significant salt tolerance phenotype. Furthermore, when cultured in the presence of exogenous β-carotene, cell pellets adopt a red/orange pigmentation indicating the incorporation of carotenoids in the cell membrane.

The Orientation Of The Pyrococcus Furiosus Transcription Factor Tfb2 In The Transcription Initiation Complex, Arati Bhattarai

Dissertations and Theses

The hyperthermophile archaeon, Pyrococcus furiosus encodes two eukaryotic TFIIB family proteins, TFB1 and TFB2. TFB1 is very similar to TFIIB in terms of sequence homology and function, whereas TFB2 is unusual as it is missing highly conserved sequences in its N-terminal domain that are present in TFIIB and TFB1. Despite this, TFB2 is effective in transcription process, albeit with lower efficiency compared to TFB1. Other archaea also contain multiple TFBs, but unlike Pyrococcus furiosus TFB2, these multiple TFBs have higher sequence homology to each other and have similar transcription efficiencies. Photochemical cross-linking experiments have shown that the B-reader of TFB …

The Fossilized Birth–Death Process For Coherent Calibration Of Divergence-Time Estimates, Tracy A. Heath, John P. Huelsenbeck, Tanja Stadler

Tracy Heath

Major Alteration In Coxsackievirus B3 Genomic Rna Structure Distinguishes A Virulent Strain From An A Virulent Strain, Jerome Prusa, Johanna Missak, Jeff Kittrell, John J. Evans, William Tapprich

Biology Faculty Publications

Coxsackievirus B3 (CV-B3) is a cardiovirulent enterovirus that utilizes a 5′ untranslated region (5′UTR) to complete critical viral processes. Here, we directly compared the structure of a 5′UTR from a virulent strain with that of a naturally occurring avirulent strain. Using chemical probing analysis, we identified a structural difference between the two 5′UTRs in the highly substituted stem-loop II region (SLII). For the remainder of the 5′UTR, we observed conserved structure. Comparative sequence analysis of 170 closely related enteroviruses revealed that the SLII region lacks conservation. To investigate independent folding and function, two chimeric CV-B3 strains were created by exchanging …