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Rhythmic Leptin Is Required For Weight Gain From Circadian Desynchronized Feeding In The Mouse, Deanna M. Arble, Martha H. Vitaterna, Fred W. Turek

Biological Sciences Faculty Research and Publications

The neuroendocrine and metabolic effects of leptin have been extensively researched since the discovery, and the later identification, of the leptin gene mutated within the ob/ob mouse. Leptin is required for optimal health in a number of physiological systems (e.g. fertility, bone density, body weight regulation). Despite the extensive leptin literature and many observations of leptin’s cyclical pattern over the 24-hour day, few studies have specifically examined how the circadian rhythm of leptin may be essential to leptin signaling and health. Here we present data indicating that a rhythmic leptin profile (e.g. 1 peak every 24 hours) leads to excessive …

Uncovering New Functions For Micrornas In Caenorhabditis Elegans, Allison L. Abbott

Biological Sciences Faculty Research and Publications

In the race to understand microRNA (miRNA) functions in development and physiology, Caenorhabditis elegans investigators were the first out of the gate with the cloning and analysis of the lin-4 and let-7 miRNAs [1,2]. The starting point of strong, penetrant loss of function phenotypes facilitated these advancements. However, subsequent functional analysis of miRNAs in C. elegans was hampered by the lack of easily observable loss-of-function phenotypes [3]. There are several possible models to account for this observation. First, redundancy between related miRNAs can account for the absence of phenotypes in mutants missing individual miRNA genes [4,5]. Second, miRNAs may also …

Effects Of Prescribed Burning On Vegetation And Swainson’S Warbler Space Use Patterns In Eastern Arkansas, Jeremy Lewis Everitts

Student Theses and Dissertations

The Swainson’s warbler Limnothlypis swainsonii) is a species of conservation concern throughout the southeastern U.S. An understanding of Swainson’s warbler habitat requirements has been documented, although little is known about how prescribed burning may improve or potentially negatively impact their populations. To learn more about the ecology of this secretive species and understand the effects of management on habitat use patterns, I studied the effects of prescribed burning on a population of Swainson’s warblers in the St. Francis National Forest in Arkansas. With the help of coworkers, I radio−tracked 45 Swainson’s warblers and collected habitat data at 1,043 sites within …

Relationships Among Reproductive Morphology, Behavior, And Testosterone In A Natural Population Of Green Anole Lizards, Michele A. Johnson, R. E. Cohen, J. R. Vandecar, J. Wade

Biology Faculty Research

Laboratory studies of reproductive systems have long supported the idea that neural and/or muscular structures used frequently are often enhanced in size. However, field studies integrating behavioral, morphological, and hormonal data are needed to better understand relationships in natural environments. We examined a natural population of green anole lizards (Anolis carolinensis) to determine whether variation in reproductive morphology both within and between the sexes paralleled differences in courtship and copulatory behaviors and circulating testosterone levels. Display rate in males was positively correlated with the sizes of the cartilage supporting the dewlap (a throat fan used in courtship and …

Educational Curriculum Standards & Standardized Educational Tests: Comparing Apples & Oranges?, William D. Stansfield

Biological Sciences

Mandated biology curriculum standards and standardized tests may vary widely from one state to another, making academic-performance comparisons among the states problematic. This report outlines the effects of the “No Child Left Behind” law and uses California as a test case against which teachers in other states may make comparisons of their own biology curriculum standards and tests. Several sources are cited that offer sample multiple-choice questions that have appeared on previous California standardized tests for sciences/life sciences/biology. These examples, and critique thereof, may help teachers better prepare their own tests to improve student performance in meeting the state's curriculum …

Season And Sex Of Host Affect Intensities Of Ectoparasites In Western Fence Lizards (Sceloporus Occidentalis) On The Central Coast Of California, Anthony S. Lumbad, Larisa K. Vredevoe, Emily N. Taylor

Biological Sciences

Seasonal variability in intensities of ectoparasites of western fence lizards (Sceloporus occidentalis) was quantified in spring, summer, and autumn 2008. Lizards were suspended over pans of water in the laboratory to enumerate replete western black-legged ticks (Ixodes pacificus) and mites. Intensity of ectoparasites was greatest in spring. On average, mites comprised the greatest proportion of ectoparasites, followed by larval and nymphal ticks, respectively. Mites were on lizards year-round. Overall intensity of ticks was greatest in spring, but low during summer and autumn. Males were more heavily parasitized by ticks than females in spring, whereas females had …

The Proteomic Response Of Sea Squirts (Genus Ciona) To Acute Heat Stress: A Global Perspective On The Thermal Stability Of Proteins, Loredana Serafini, Jay B. Hann, Dietmar Kültz, Lars Tomanek

Biological Sciences

Congeners belonging to the genus Ciona have disparate distributions limited by temperature. Ciona intestinalis is more widespread with a cosmopolitan distribution ranging from tropical to sub-arctic zones, while Ciona savignyi is limited to temperate-latitudes of the northern Pacific Ocean. To compare the heat stress response between congeners, we quantified changes in protein expression using proteomics. Animals were exposed to 22 °C, 25 °C, and 28 °C for 6 h, then recovered at a control temperature (13 °C) for 16 h (high heat stress experiment). In a second experiment we exposed animals to lower levels of heat stress at 18 °C, …

Sex Chromosome Mosaicism And Hybrid Speciation Among Tiger Swallowtail Butterflies, Krushnamegh Kunte, Cristina Shea, Matthew Aardema, J. Mark Scriber, Thomas E. Juenger, Lawrence E. Gilbert, Marcus R. Kronforst

Department of Biology Faculty Scholarship and Creative Works

Hybrid speciation, or the formation of a daughter species due to interbreeding between two parental species, is a potentially important means of diversification, because it generates new forms from existing variation. However, factors responsible for the origin and maintenance of hybrid species are largely unknown. Here we show that the North American butterfly Papilio appalachiensis is a hybrid species, with genomic admixture from Papilio glaucus and Papilio canadensis. Papilio appalachiensis has a mosaic phenotype, which is hypothesized to be the result of combining sex-linked traits from P. glaucus and P. canadensis. We show that P. appalachiensis' Z-linked genes associated with …

Analyses Of Sorex Longirostris Distribution In Arkansas And Across The Mississippi River, Garrett Adam Mikel

Theses and Dissertations

The southeastern shrew (Sorex longirostris) is considered uncommon and a Species of Greatest Conservation Need in Arkansas, exhibiting an apparent gap in eastern Arkansas. Soricinae are exceptionally small and short-lived with limited dispersal, making them especially prone to speciation through long-term zoogeographic barriers to gene flow consistent with phylogeographic category 1. Therefore, I compiled Arkansas occurrences, evaluated persistence at previous capture sites in the state, surveyed additional counties, quantified microhabitat at my capture locations, and evaluated systematic status of S. longirostris east and west of the Mississippi River using mitochondrial DNA. Number of documented specimens in Arkansas has increased to …

Expression Of Hyp-O-Glycan Modified Protein In Plant Using Transient And Cell Culture Platforms, Di Wu

Student Theses and Dissertations

Plants have emerged as cost-effective, efficient factories to produce foreign proteins of pharmaceutical importance. Agrobacterium-mediated transient expression provides a rapid and simple plant system for production but is often linked with low protein recovery. Plant-specific hydroxyproline (Hyp)-O-glycosylation has been demonstrated to increase protein stability and solubility (termed Hyp-Glyco technology). To test if Hyp-glycans attached to a target protein can improve overall transiently expressed protein yields, EGFP reporter protein was expressed as fusion with a 5 or 32 repeats of Ser-Pro motif ((SP)5 or (SP)32 ) that directs extensive Hyp-O-glycosylation. My thesis project has provided the first demonstration that the Hyp-O-glcosylation …

Mucosal Immunization With A Staphylococcus Aureus Isda-Cholera Toxin A2/B Chimera Induces Antigen-Specific Th2-Type Responses In Mice, Britni M. Arlian, Juliette Tinker

Biology Faculty Publications and Presentations

Staphylococcus aureus is a leading cause of opportunistic infection worldwide and a significant public health threat. The iron-regulated surface determinant A (IsdA) adhesin is essential for S. aureus colonization on human nasal epithelial cells and plays an important role in iron acquisition and resistance to human skin defenses. Here we investigated the murine immune response to intranasal administration of a cholera toxin (CT) A₂/B chimera containing IsdA. Plasmids were constructed to express the IsdA-CTA₂/B chimera and control proteins in E. coli. Proper construction of the chimera was verified by SDS-PAGE, western blot, GM1 ELISA, and …

Biotic Resistance Via Granivory: Establishment By Invasive, Naturalized, And Native Asters Reflects Generalist Preference, Dean E. Pearson, Ragan M. Callaway, John L. Maron

Biological Sciences Faculty Publications

Escape from specialist natural enemies is frequently invoked to explain exotic plant invasions, but little attention has been paid to how generalist consumers in the recipient range may influence invasion. We examined how seed preferences of the widespread generalist granivore Peromyscus maniculatus related to recruitment of the strongly invasive exotic Centaurea stoebe and several weakly invasive exotics and natives by conducting laboratory feeding trials and seed addition experiments in the field. Laboratory feeding trials showed that P. maniculatus avoided consuming seeds of C. stoebe relative to the 12 other species tested, even when seeds of alternative species were 53–94% smaller …

Auditory Selectivity For Acoustic Features That Confer Species Recognition In The Túngara Frog, Lisa A. Mangiamele, Sabrina S. Burmeister

Biological Sciences: Faculty Publications

In anurans, recognition of species-specific acoustic signals is essential to finding a mate. In many species, behavioral tests have elucidated which acoustic features contribute to species recognition, but the mechanisms by which the brain encodes these species-specific signal components are less well understood. The túngara frog produces a 'whine' mating call that is characterized by a descending frequency sweep. However, much of the signal is unnecessary for recognition, as recognition behavior can be triggered by a descending two-tone step that mimics the frequency change in a portion of the whine. To identify the brain regions that contribute to species recognition …

Activation Of Jnk Signaling Mediates Amyloid-Ss- Dependent Cell Death, Meghana Tare, Rohan Modi, Jaison Nainaparampil, Oorvashi Roy Puli, Shimpi Bedi, Pedro Fernandez-Funez, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

Background: Alzheimer's disease (AD) is an age related progressive neurodegenerative disorder. One of the reasons for Alzheimer's neuropathology is the generation of large aggregates of Aß42 that are toxic in nature and induce oxidative stress, aberrant signaling and many other cellular alterations that trigger neuronal cell death. However, the exact mechanisms leading to cell death are not clearly understood.

Methodology/Principal Findings: We employed a Drosophila eye model of AD to study how Aß42 causes cell death. Misexpression of higher levels of Aß42 in the differentiating photoreceptors of fly retina rapidly induced aberrant cellular phenotypes and cell death. We found that …

Single Molecule Analysis Of The Arabidopsis Fra1 Kinesin Shows That It Is A Functional Motor Protein With Unusually High Processivity, Chuanmei Zhu, Ram Dixit

Biology Faculty Research

The Arabidopsis FRA1 kinesin contributes to the organization of cellulose microfibrils through an unknown mechanism. The cortical localization of this kinesin during interphase raises the possibility that it transports cell wall-related cargoes along cortical microtubules that either directly or indirectly influence cellulose microfibril patterning. To determine whether FRA1 is an authentic motor protein, we combined bulk biochemical assays and single molecule fluorescence imaging to analyze the motor properties of recombinant, GFP-tagged FRA1 containing the motor and coiled-coil domains (designated as FRA1(707)–GFP). We found that FRA1(707)–GFP binds to microtubules in an ATP-dependent manner and that its ATPase activity is dramatically stimulated …

The Deg/Enac Protein Mec-10 Regulates The Transduction Channel Complex In Caenorhabditis Elegans Touch Receptor Neurons, Jóhanna Árnadóttir, Robert O'Hagan, Yushu Chen, Miriam B. Goodman, Martin Chalfie

Department of Biology Faculty Scholarship and Creative Works

Gentle touch sensation in Caenorhabditis elegans is mediated by the MEC-4/MEC-10 channel complex, which is expressed exclusively in six touch receptor neurons (TRNs). The complex contains two pore-forming subunits, MEC-4 and MEC-10, as well as the accessory subunits MEC-2, MEC-6, and UNC-24. MEC-4 is essential for channel function, but beyond its role as a pore-forming subunit, the functional contribution of MEC-10 to the channel complex and to touch sensation is unclear.Weaddressed this question using behavioral assays, in vivo electrophysiological recordings from TRNs, and heterologous expression of mutant MEC-10 isoforms. Animals with a deletion in mec-10 showed only a partial loss …

A Moderate Elevation Of Circulating Levels Of Igf-I Does Not Alter Erbb2 Induced Mammary Tumorigenesis, Robert K. Dearth, Isere Kuiatse, Yu-Fen Wang, Lan Liao, Susan G. Hilsenbeck, Powel H. Brown, Jianming Xu, Adrian V. Lee

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

Background

Epidemiological evidence suggests that moderately elevated levels of circulating insulin-like growth factor-I (IGF-I) are associated with increased risk of breast cancer in women. How circulating IGF-I may promote breast cancer incidence is unknown, however, increased IGF-I signaling is linked to trastuzumab resistance in ErbB2 positive breast cancer. Few models have directly examined the effect of moderately high levels of circulating IGF-I on breast cancer initiation and progression. The purpose of this study was to assess the ability of circulating IGF-I to independently initiate mammary tumorigenesis and/or accelerate the progression of ErbB2 mediated mammary tumor growth.

Methods

We crossed heterozygous …

Estimating The Timing Of Early Eukaryotic Diversification With Multigene Molecular Clocks, Laura Wegener Parfrey, Daniel J.G. Lahr, Andrew H. Knoll, Laura A. Katz

Biological Sciences: Faculty Publications

Although macroscopic plants, animals, and fungi are the most familiar eukaryotes, the bulk of eukaryotic diversity is microbial. Elucidating the timing of diversification among the more than 70 lineages is key to understanding the evolution of eukaryotes. Here, we use taxon-rich multigene data combined with diverse fossils and a relaxed molecular clock framework to estimate the timing of the last common ancestor of extant eukaryotes and the divergence of major clades. Overall, these analyses suggest that the last common ancestor lived between 1866 and 1679 Ma, consistent with the earliest microfossils interpreted with confidence as eukaryotic. During this interval, the …

Physiological Trade-Offs In Self-Maintenance: Plumage Molt And Stress Physiology In Birds, Jamie M. Cornelius, Nicole Perfito, Richard Zann, Creagh W. Breuner, Thomas P. Hahn

Biological Sciences Faculty Publications

Trade-offs between self-maintenance processes can affect life-history evolution. Integument replacement and the stress response both promote self-maintenance and affect survival in vertebrates. Relationships between the two processes have been studied most extensively in birds, where hormonal stress suppression is down regulated during molt in seasonal species, suggesting a resource-based trade-off between the two processes. The only species found to differ are the rock dove and Eurasian tree sparrow, at least one of which performs a very slow molt that may reduce resource demands during feather growth, permitting investment in the stress response. To test for the presence of a molt–stress …

Dynamic Characterization Of The Ikk:Κbα:Nfκb Negative Feedback Loop Using Real-Time Bioluminescence Imaging, Britney Moss

All Theses and Dissertations (ETDs)

The transcription factor NF-κB is a pivotal regulator of mammalian cell function, modulating genes implicated in cellular stress responses, proliferation, differentiation, cell survival and apoptosis, as well as immune and inflammatory responses. Improper regulation of NF-κB signaling has been implicated in a myriad of human pathological disorders, including cardiovascular and neurodegenerative diseases, chronic inflammation, and various cancers. A key regulatory node within canonical NF-κB signaling is the IKK:NF-κB: IκBα negative feedback loop that plays a major role in regulating the strength and duration of NF-κB transcriptional activity. We have developed and characterized an unique bioluminescent reporter (κB_5àIκBα-FLuc) …

The Abundance And Infection Status Of Anopheles Spp. Mosquitoes At Three Sites In Loudoun County, Northern Virginia, Priya Krishnan

Theses and Dissertations

Malaria is a re-emerging infectious disease with approximately half of the world's population at risk. In the US, since the 1950’s the Center for Disease Control (CDC) has been reporting between 1,000 and 1,500 cases of malaria every year. A majority of these cases were among US travellers and were attributed to Plasmodium falciparum. In August 2002, two cases of human malaria due to Plasmodium vivax were reported in Loudoun County, Northern Virginia. The Center for Disease Control and Prevention concluded that these cases were acquired locally. This was because of an absence of other risk factors such as international …

Down-Regulation Of Krüppel-Like Factor-4 (Klf4) By Microrna-143/145 Is Critical For Modulation Of Vascular Smooth Muscle Cell Phenotype By Transforming Growth Factor-Β And Bone Morphogenetic Protein 4, Brandi N. Davis-Dusenbery, Mun Chun Chan, Kelsey E. Reno, Alexandra S. Weisman, Matthew D. Layne, Giorgio Lagna, Akiko Hata

Biology

In the postnatal vasculature, fully differentiated and quiescent vascular smooth muscle cells (VSMCs) in a “contractile” phenotype are required for the normal regulation of vascular tone. The transforming growth factor-β (TGF-β) superfamily of growth factors (TGF-βs and bone morphogenetic proteins (BMPs)) are potent inducers of contractile phenotype and mediate (i) induction of contractile genes, and (ii) inhibition of VSMC growth and migration. Transcription of contractile genes is positively regulated by a regulatory DNA element called a CArG box. The CArG box is activated by the binding of serum response factor and its coactivators, myocardin (Myocd) or Myocd-related transcription factors (MRTFs). …

Comparative Genomics Of The Pathogenic Ciliate Ichthyophthirius Multifiliis, Its Free-Living Relatives And A Host Species Provide Insights Into Adoption Of A Parasitic Lifestyle And Prospects For Disease Control, Robert S. Coyne, Linda Hannick, Dhanasekaran Shanmugam, Jessica B. Hostetler, Daniel Brami, Vinita S. Joardar, Justin Johnson, Diana Radune, Irtisha Singh, Jonathan H. Badger, Ujjwal Kumar, Milton Saier, Yufeng Wang, Hong Cai, Jianying Gu, Michael W. Mather, Akhil B. Vaidya, David E. Wilkes, Vidyalakshmi Rajagopalan, David J. Asai, Chad G. Pearson, Robert C. Findly, Harry W. Dickerson, Martin Wu, Cindy Martens, Yves Van De Peer, David S. Roos, Donna M. Cassidy-Hanley, Theodore G. Clark

Publications and Research

Background

Ichthyophthirius multifiliis, commonly known as Ich, is a highly pathogenic ciliate responsible for 'white spot', a disease causing significant economic losses to the global aquaculture industry. Options for disease control are extremely limited, and Ich's obligate parasitic lifestyle makes experimental studies challenging. Unlike most well-studied protozoan parasites, Ich belongs to a phylum composed primarily of free-living members. Indeed, it is closely related to the model organism Tetrahymena thermophila. Genomic studies represent a promising strategy to reduce the impact of this disease and to understand the evolutionary transition to parasitism.

Results

We report the sequencing, assembly and annotation …

Differential Gene Expression In Male And Female Rainbow Trout Embryos Prior To The Onset Of Gross Morphological Differentiation Of The Gonads, Matthew C. Hale, Peng Xu, Julie Scardina, Paul A. Wheeler, Gary H. Thorgaard, Krista M. Nichols

Department of Biological Sciences Faculty Publications

Background: There are large differences between the sexes at the genetic level; these differences include heterogametic sex chromosomes and/or differences in expression of genes between the sexes. In rainbow trout (Oncorhynchus mykiss) qRT-PCR studies have found significant differences in expression of several candidate sex determining genes. However, these genes represent a very small fraction of the genome and research in other species suggests there are large portions of the transcriptome that are differentially expressed between the sexes. These differences are especially noticeable once gonad differentiation and maturation has occurred, but less is known at earlier stages of development. Here we …

Characterizing The Distribution Of Planktonic Fecal Bacteria In The James River, Richmond, Virginia, John Furry

Theses and Dissertations

Surface waters containing fecal bacteria present significant public health risks. Understanding the sources of and factors affecting the distribution of fecal-indicating bacteria is necessary to predict potential illnesses more effectively. This thesis presents two studies on the distribution of fecal bacteria in the James River through Richmond, Virginia. Chapter 1 describes nearly 11 years of water quality, climate, and hydrologic data that occurred with changes in Escherichia coli concentrations, concluding that Richmond contributes significant quantities of fecal bacteria to the James River, and that the distribution of these bacteria varies seasonally. Chapter 2 details the development of Polymerase Chain Reaction …

Rumbling In The Benthos: Acoustic Ecology Of The California Mantis Shrimp Hemisquilla Californiensis, E. Staaterman, C. Clark, A. Gallagher, M. Devries, T. Claverie, S. Patek

Faculty Publications, Biological Sciences

Although much research has focused on acoustic mapping and exploration of the benthic environment, little is known about the acoustic ecology of benthic organisms, particularly benthic crustaceans. Through the use of a coupled audio–video system, a hydrophone array, and an autonomous recording unit, we tested several hypotheses about the field acoustics of a benthic marine crustacean, Hemisquilla califor­niensis. Living in muddy burrows in southern California, these large mantis shrimp produce low frequency ‘rumbles’ through muscle vibrations. First, we tested whether acoustic signals are similar in the field and in the laboratory, and discovered that field-produced rumbles are more acoustically and …

Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley

STAR Program Research Presentations

Salmonids, such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), are a staple economic, recreational, tribal, and environmental resource, yet many populations are unsustainable. This study was part of a broad scale effort to monitor the impact of downstream migration obstacles on juvenile salmonid health and survival, which is an essential step towards increasing Smolt-to-Adult Return ratios (SARs). The objective of this study was to determine if juvenile Chinook salmon and steelhead exhibit differing quantities of alphaII-Spectrin Breakdown Products (SBDPs) over two consecutive spring migration periods, indicative of neurogenesis rate and/or biological response to head …

Addressing Biased Occurrence Data In Predicting Potential Sierra Nevada Red Fox Habitat For Survey Prioritization, Casey Cleve, John D. Perrine, Barbara Holzman, Ellen Hines

Biological Sciences

The Sierra Nevada red fox Vulpes vulpes necator is listed as a threatened species under the California Endangered Species Act. It originally occurred throughout California’s Cascade and Sierra Nevada mountain regions. Its current distribution is unknown but should be determined in order to guide management actions. We used occurrence data from the only known population, in the Lassen Peak region of northern California, combined with climatic and remotely sensed variables, to predict the species’ potential distribution throughout its historic range. These model predictions can guide future surveys to locate additional fox populations. Moreover, they allow us to compare the relative …

Sound Production In Two Loricariid Catfishes, Amanda Lynn Webb

Masters Theses & Specialist Projects

Many families of catfish produce sounds via pectoral spine stridulation and/or swim bladder compression using sonic muscles attached to the swim bladder. The sound production capabilities and characteristics in Loricariidae, the largest catfish family, have not been well examined. Sounds produced by two loricariid catfish species, Macrotocinclus affinis and Pterygoplichthys gibbiceps were recorded. Both species produce broad band calls via pectoral spine stridulation. These species produce sounds by rubbing the ridges of the dorsal process of the pectoral spine base against the groove of the pectoral girdle. Call duration was generally shorter in M. affinis (2-15 ms) as opposed to …

Action Spectrum For Photoentrainment Of The Circadian Clock In Wild-Type Chlamydomonas Reinhardtii, Jennifer Forbes=Stovall

Masters Theses & Specialist Projects

The circadian clock is an endogenous timer that oscillates with a period of approximately 24 hours and is reset upon environmental time cues such as the daily light/ dark or temperature cycles. Chlamydomonas reinhardtii is an ideal model organism for research on the circadian clock, because it shows several well-characterized behaviors that exhibit a circadian rhythm. Its circadian rhythm of phototaxis (swimming toward light) has been automated. Former action spectrum studies using the circadian phototaxis rhythm as an indicator surprisingly found that pulses of blue light were not effective in resetting the circadian clock of dark-adapted cells. This may have …