Life Sciences Commons^™

Inducing Task-Relevant Responses To Speech In The Sleeping Brain, Sid Kouider, Thomas Andrillon, Leonardo S. Barbosa, Louise Goupil, Tristan A. Bekinschtein

Biology Faculty Publications

Falling asleep leads to a loss of sensory awareness and to the inability to interact with the environment [1]. While this was traditionally thought as a consequence of the brain shutting down to external inputs, it is now acknowledged that incoming stimuli can still be processed, at least to some extent, during sleep [2]. For instance, sleeping participants can create novel sensory associations between tones and odors [3] or reactivate existing semantic associations, as evidenced by event-related potentials [4; 5; 6 ; 7]. Yet, the extent to which the brain …

Energetic Demands Of Immature Sea Otters From Birth To Weaning: Implications For Maternal Costs, Reproductive Behavior And Population-Level Trends, Nicole Thometz, M. T. Tinker, M. M. Staedler, K. A. Mayer, T. M. Williams

Biology Faculty Publications

Sea otters (Enhydra lutris) have the highest mass-specific metabolic rate of any marine mammal, which is superimposed on the inherently high costs of reproduction and lactation in adult females. These combined energetic demands have been implicated in the poor body condition and increased mortality of female sea otters nearing the end of lactation along the central California coast. However, the cost of lactation is unknown and currently cannot be directly measured for this marine species in the wild. Here, we quantified the energetic demands of immature sea otters across five developmental stages as a means of assessing the …

Between Two Fern Genomes, E. B. Sessa, J. A. Banks, M. S. Barker, J. P. Der, A. M. Duffy, S. W. Graham, M. Hasebe, J. Langdale, F. W. Li, D. B. Marchant, K. M. Pryer, C. J. Rothfels, S. J. Roux, M. L. Salmi, E. M. Sigel, D. E. Soltis, P. S. Soltis, D. W. Stevenson, Paul G. Wolf

Biology Faculty Publications

Ferns are the only major lineage of vascular plants not represented by a sequenced nuclear genome. This lack of genome sequence information significantly impedes our ability to understand and reconstruct genome evolution not only in ferns, but across all land plants. Azolla and Ceratopteris are ideal and complementary candidates to be the first ferns to have their nuclear genomes sequenced. They differ dramatically in genome size, life history, and habit, and thus represent the immense diversity of extant ferns. Together, this pair of genomes will facilitate myriad large-scale comparative analyses across ferns and all land plants. Here we review the …

A Samoan Hebeloma With Phylogenetic Ties To The Western Pacific, Bradley R. Kropp

Biology Faculty Publications

Hebeloma ifeleletorum is described as a new species from American Samoa. Based on analyses of ITS and combined nLSU-ITS datasets H. ifeleletorum clusters with but is distinct from described species that have been placed in the genus Anamika by some. The phylogenetic relationship of H. ifeleletorum to the genus Anamika from Asia and to other species from Australia and New Caledonia suggests that H. ifeleletorum has origins in the western Pacific.

Sarpa Salpa Herbivory On Shallow Reaches Of Posidonia Oceanica Beds, Latina Steele, Kelly M. Darnell, Just Cebrián, Jose Luis Sanchez-Lizaso

Biology Faculty Publications

Sarpa salpa herbivory on shallow reaches of Posidonia oceanica beds.— Here, we examined the temporal and small–scale spatial variability of grazing by the herbivorous fish Sarpa salpa on shallow beds of the temperate seagrass Posidonia oceanica. Herbivory intensity expressed as the percent of leaf area taken by fish bites was higher in September 2006 than in February 2007, and at 0.5 m than at 1.5 m during both sampling times. All S. salpa feeding at the shallow locations studied were juveniles, with bite sizes ranging from 0.03 to 0.62 cm2. Juveniles feeding at 1.5 m were larger in February 2007 …

Commelina Benghalensis New To Virginia, W. John Hayden

Biology Faculty Publications

This is the first report of Commelina benghalensis (Benghal dayflower, tropical spiderwort) in Virginia. Three mature plants with intertwined stems bearing numerous chasmogamous and cleistogamous flowers were discovered as weeds in a landscape planting of hybrid Hemerocallis, hybrid Iris, and a dwarf cultivar of Nandina domestica; nine nonreproductive seedlings were found about one meter distant in the same flower bed.

Intracellular Recording, Sensory Field Mapping, And Culturing Identified Neurons In The Leech, Hirudo Medicinalis, Josh Titlow, Zana R. Majeed, John G. Nicholls, Robin L. Cooper

Biology Faculty Publications

The freshwater leech, Hirudo medicinalis, is a versatile model organism that has been used to address scientific questions in the fields of neurophysiology, neuroethology, and developmental biology. The goal of this report is to consolidate experimental techniques from the leech system into a single article that will be of use to physiologists with expertise in other nervous system preparations, or to biology students with little or no electrophysiology experience. We demonstrate how to dissect the leech for recording intracellularly from identified neural circuits in the ganglion. Next we show how individual cells of known function can be removed from …

Neural Circuit Recording From An Intact Cockroach Nervous System, Josh Titlow, Zana R. Majeed, H. Bernard Hartman, Ellen Burns, Robin L. Cooper

Biology Faculty Publications

The cockroach ventral nerve cord preparation is a tractable system for neuroethology experiments, neural network modeling, and testing the physiological effects of insecticides. This article describes the scope of cockroach sensory modalities that can be used to assay how an insect nervous system responds to environmental perturbations. Emphasis here is on the escape behavior mediated by cerci to giant fiber transmission in Periplaneta americana. This in situ preparation requires only moderate dissecting skill and electrophysiological expertise to generate reproducible recordings of neuronal activity. Peptides or other chemical reagents can then be applied directly to the nervous system in solution …

Novel Neuroprotective Function Of Apical-Basal Polarity Genecrumbs In Amyloid Beta 42 (Aβ42) Mediated Neurodegeneration, Andrew Steffensmeier, Meghana Tare, Oorvashi Roy Puli, Rohan Modi, Jaison Nainaparampil, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

Alzheimer's disease (AD, OMIM: 104300), a progressive neurodegenerative disorder with no cure to date, is caused by the generation of amyloid-beta-42 (Aβ42) aggregates that trigger neuronal cell death by unknown mechanism(s). We have developed a transgenic Drosophilaeye model where misexpression of human Aβ42 results in AD-like neuropathology in the neural retina. We have identified an apical-basal polarity gene crumbs (crb) as a genetic modifier of Aβ42-mediated-neuropathology. Misexpression of Aβ42 caused upregulation of Crb expression, whereas downregulation of Crb either by RNAi or null allele approach rescued the Aβ42-mediated-neurodegeneration. Co-expression of full length Crb with Aβ42 increased severity of Aβ42-mediated-neurodegeneration, …

Homeotic Gene Teashirt (Tsh) Has A Neuroprotective Function In Amyloid-Beta 42 Mediated Neurodegeneration, Michael T. Moran, Meghana Tare, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

Background: Alzheimer's disease (AD) is a debilitating age related progressive neurodegenerative disorder characterized by the loss of cognition, and eventual death of the affected individual. One of the major causes of AD is the accumulation of Amyloid-beta 42 (Aβ42) polypeptides formed by the improper cleavage of amyloid precursor protein (APP) in the brain. These plaques disrupt normal cellular processes through oxidative stress and aberrant signaling resulting in the loss of synaptic activity and death of the neurons. However, the detailed genetic mechanism(s) responsible for this neurodegeneration still remain elusive.

Methodology/Principal Findings: We have generated a transgenic Drosophila eye model where …

The Tadpole Of Leptodactylus Caatingae Heyer & Juncá, 2003 (Anura: Leptodactylidae): External Morphology, Internal Anatomy, And Natural History, Felipe De Madeiros Magalhães, Adrian Antonio Garda, Ralita Ferreira Amado, Rafael O. De Sá

Biology Faculty Publications

We describe and illustrate the external morphology, oral disc, chondrocranium, and internal oral anatomy of Leptodactylus caatingae larvae. We analyze the internal oral anatomy using scanning electron microscopy of a larva in Gosner, stage 38 and chondrocranial anatomy is reported for Gosner stage 34. The tadpole at Gosner stage 38 has a globular body shape with low tail fins and a ventral oral disc bordered by two rows of marginal papillae on most of the disc, except for the anterior labium and a medial portion of the posterior labium where papillae are simple; a wide rostral gap is present, labial …

Proprioception And Tension Receptors In Crab Limbs: Student Laboratory Exercises, Zana R. Majeed, Josh Titlow, H. Bernard Hartman, Robin L. Cooper

Biology Faculty Publications

The primary purpose of these procedures is to demonstrate for teaching and research purposes how to record the activity of living primary sensory neurons responsible for proprioception as they are detecting joint position and movement, and muscle tension. Electrical activity from crustacean proprioceptors and tension receptors is recorded by basic neurophysiological instrumentation, and a transducer is used to simultaneously measure force that is generated by stimulating a motor nerve. In addition, we demonstrate how to stain the neurons for a quick assessment of their anatomical arrangement or for permanent fixation. Staining reveals anatomical organization that is representative of chordotonal organs …

Muc1 Regulates Expression Of Multiple Micrornas Involved In Pancreatic Tumor Progression, Including The Mir-200c/141 Cluster, Ashley M. Mohr, Jennifer M. Bailey, Michelle E. Lewallen, Xiang Liu, Prakash Radhakrishnan, Fang Yu, William Tapprich, Michael A. Hollingsworth

Biology Faculty Publications

MUC1 is a transmembrane glycoprotein that modulates transcription via its cytoplasmic domain. We evaluated the capacity of MUC1 to regulate the global transcription of microRNAs in pancreatic cancer cells expressing MUC1. Results indicated that MUC1 regulated expression of at least 103 microRNAs. We evaluated further regulation of the microRNA transcript cluster miR-200c/141, which was among the most highly regulated microRNAs. We found that MUC1 directly interacted with ZEB1, a known transcriptional repressor of the miR-200c/141 cluster, at the promoter of miR-200c/141, and further reduced transcript production. These data indicate that signaling through MUC1 influences cancer progression by regulating transcription of …

Neighborhoods Have Little Effect On Fungal Attack Or Insect Predation Of Developing Seeds In A Grassland Biodiversity Experiment, Noelle G. Beckman, Ray Dybzinski, G. David Tilman

Biology Faculty Publications

Numerous observational studies have documented conspecific negative density-dependence that is consistent with the Janzen–Connell Hypothesis (JCH) of diversity maintenance. However, there have been few experimental tests of a central prediction of the JCH: that removing host-specific enemies should lead to greater increases in per capita recruitment in areas of higher host density or lower relative phylogenetic diversity. Using spatially randomized plots of high and low host biomass in a temperate grassland biodiversity experiment, we treated developing seedheads of six prairie perennials to factorial applications of fungicide and insecticide. We measured predispersal seed production, seed viability, and seedling biomass. Results were …

Redbud Seedpods Hold Surprises, W. John Hayden

Biology Faculty Publications

As fall advances across the Old Dominion, canopies of redbud, the 2013 VNPS Wildflower of the Year, transform themselves from green to gold, revealing seed pods also changing color from pale green to dark chocolaty brown. These seedpods, which may be retained on the tree into winter, are typical legume fruits, the product of the flower’s simple pistil, each containing several seeds. Unlike most legumes, however, redbud seed pods seem disinclined to open and release individual seeds for dispersal. Redbud fruits tend to disperse intact. Once on the ground, the inevitable action of weather and microbes gradually degrades the pod, …

Fight Or Flight: Parental Decisions About Predators At Nests Of Northern Bobwhites (Colinus Virginianus), Susan N. Ellis-Felege, Jonathan S. Burnam, William E. Palmer, D. Clay Sisson, John P. Carroll

Biology Faculty Publications

Patterns of nest defense against predators by ground-nesting bird species in the wild are poorly understood, largely because of a historical inability to directly monitor nests. Most nest-defense studies have observed responses elicited from artificial predators or human observers presented to nesting birds, and few have attempted to present these events in the context of predator—prey relationships found in the wild. We hypothesized that predator threat level (e.g., the threat posed to the clutch or to the clutch and the attending adult), parental characteristics, clutch investment, and future reproductive opportunities would influence avian nest-defense decisions. During 1999–2006, we examined predation …

Consequences Of Seed Dispersal For Plant Recruitment In Tropical Forests: Interactions Within The Seedscape, Noelle G. Beckman, Haldre S. Rogers

Biology Faculty Publications

Seed dispersal sets the stage for the suite of biotic and abiotic interactions that determine the fate of individual seeds. In this review, we first focus on how dispersal influences the 'seedscape', or the combination of abiotic and biotic factors that affect the probability of recruitment once a seed has reached its final location. We review recent papers that examine the effect of different dispersal vectors on (1) the quality of the habitat in which a seed lands; (2) the distance seeds are dispersed from the parent tree; and (3) the density and composition of plant s within the neighborhood …

High-Throughput Rna Sequencing Of Pseudomonas-Infected Arabidopsis Reveals Hidden Transcriptome Complexity And Novel Splice Variants, Brian E. Howard, Qiwen Hu, Ahmet Can Babaoglu, Manan Chandra, Monica Borghi, Xiaoping Tan, Luyan He, Heike Winter-Sederoff, Walter Gassmann, Paola Veronese, Steffen Heber

Biology Faculty Publications

We report the results of a genome-wide analysis of transcription in Arabidopsis thaliana after treatment with Pseudomonas syringae pathovar tomato. Our time course RNA-Seq experiment uses over 500 million read pairs to provide a detailed characterization of the response to infection in both susceptible and resistant hosts. The set of observed differentially expressed genes is consistent with previous studies, confirming and extending existing findings about genes likely to play an important role in the defense response to Pseudomonas syringae. The high coverage of the Arabidopsis transcriptome resulted in the discovery of a surprisingly large number of alternative splicing (AS) events …

Dreadds In Drosophila: A Pharmacogenetic Approach For Controlling Behavior, Neuronal Signaling, And Physiology In The Fly, Jaime Becnel, Oralee Johnson, Zana R Majeed, Vi Tran, Bangning Yu, Bryan L. Roth, Robin L. Cooper, Edmund K. Kerut, Charles D. Nichols

Biology Faculty Publications

We have translated a powerful genetic tool, designer receptors exclusively activated by designer drugs (DREADDs), from mammalian systems to Drosophila melanogaster to selectively, rapidly, reversibly, and dose-dependently control behaviors and physiological processes in the fly. DREADDs are muscarinic acetylcholine G protein-coupled receptors evolved for loss of affinity to acetylcholine and for the ability to be fully activated by an otherwise biologically inert chemical, clozapine-N-oxide. We demonstrate its ability to control a variety of behaviors and processes in larvae and adults, including heart rate, sensory processing, diurnal behavior, learning and memory, and courtship. The advantages of this particular technology include the …

Transcriptome Analysis Of Two Buffalograss Cultivars, Michael Wachholtz, Tiffany Heng-Moss, Paul Twigg, Lisa Baird, Guoqing Lu, Keenan Amundsen

Biology Faculty Publications

Background: Buffalograss [Buchloë dactyloides (Nutt.) Engel. syn. Bouteloua dactyloides (Nutt.) Columbus] is a United States native turfgrass species that requires less irrigation, fungicides and pesticides compared to more commonly used turfgrass species. In areas where water is limited, interest in this grass species for lawns is increasing. While several buffalograss cultivars have been developed through buffalograss breeding, the timeframe for new cultivar development is long and is limited by a lack of useful genetic resources. Two high throughput next-generation sequencing techniques were used to increase the genomic resources available for buffalograss.

Results: Total RNA was extracted and …

Integrated Carbon Budget Models For The Everglades Terrestrial-Coastal-Oceanic Gradient: Current Status And Needs For Inter-Site Comparisons, Tiffany G. Troxler, Evelyn Gaiser, Jordan Barr, Jose D. Fuentes, Rudolf Jaffe, Daniel L. Childers, Ligia Collado-Vides, Victor H. Rivera-Monroy, Edward Castaneda-Moya, William Anderson, Randy Chambers, Meilian Chen, Carlos Coronado-Molina, Stephen E. Davis, Victor Engel, Carl Fitz, James Fourqurean, Tom Frankovich, John Kominoski, Chris Madden, Sparkle L. Malone, Steve F. Oberbauer, Paulo Olivas, Jennifer Richards, Colin Saunders, Jessica L. Schedlbauer, Leonard J. Scinto, Fred Sklar, Tom Smith, Joseph M. Smoak, Gregory Starr, Robert R. Twilley, Kevin Whelan

Biology Faculty Publications

No abstract provided.

Planarians Require An Intact Brain To Behaviorally React To Cocaine, But Not To React To Nicotine, Oné R. Pagán, Sean Deats, Debra Baker, Erica Montgomery, Galia Wilk, Matthew Tenaglia, Joshua Semon

Biology Faculty Publications

Planarians possess a rudimentary brain with many features in common with vertebrate brains. They also display a remarkable capacity for tissue regeneration including the complete regeneration of the nervous system. Using the induction of planarian seizure-like movements (pSLMs) as a behavioral endpoint, we demonstrate that an intact nervous system is necessary for this organism to react to cocaine exposure, but not necessary to react to nicotine administration. Decapitated planarians (Girardia tigrina) display pSLMs indistinguishable from intact worms when exposed to nicotine, but cocaine-induced pSLMs are reduced by about 95% upon decapitation. Decapitated worms recover their normal sensitivity to cocaine within …

The Genus Odontophrynus (Anura: Odontophrynidae): A Larval Perspective, Filipe Augusto C. Do Nascimento, Tamí Mott, José A. Langone, Christine A. Davis, Rafael O. De Sá

Biology Faculty Publications

The genus Odontophrynus consists of 11 species of medium-sized frogs distributed across south and east South America. This study examines and describes the chondrocrania and oral cavities of 0. americanus, 0. maisuma, 0. carvalhoi, and 0. cu/tripes, and reviews current knowledge about the larval external morphology of the genus. Twenty-one tadpoles were cleared and double-stained for chondrocranium description and five tadpoles were dissected for analysis in a scanning electron microscope. The presence of a tectum parientale may be considered here as a putative synapomorphy of the genus. The 0. americanus and 0. cu/tripes species groups were partially differentiated by the …

Recurrent Modification Of A Conserved Cis-Regulatory Element Underlies Fruit Fly Pigmentation Diversity, William A. Rogers, Joseph R. Salomone, David J. Tacy, Eric M. Camino, Kristen A. Davis, Mark Rebeiz, Thomas M. Williams

Biology Faculty Publications

The development of morphological traits occurs through the collective action of networks of genes connected at the level of gene expression. As any node in a network may be a target of evolutionary change, the recurrent targeting of the same node would indicate that the path of evolution is biased for the relevant trait and network. Although examples of parallel evolution have implicated recurrent modification of the same gene and cis-regulatory element (CRE), little is known about the mutational and molecular paths of parallel CRE evolution. InDrosophila melanogaster fruit flies, the Bric-à-brac (Bab) transcription factors control the development …

Pharmacological Analysis Of Dopamine Modulation In The Drosophila Melanogaster Larval Heart, Josh S. Titlow, Jenna M. Rufer, Kayla E. King, Robin L. Cooper

Biology Faculty Publications

Dopamine (DA) and other neurotransmitters affect nonneuronal tissues in insects by circulating in the hemolymph. In several organisms, DA has been shown to modulate distinct aspects of cardiac function but the signal transduction pathways that mediate dopaminergic effects on the heart are not well characterized. Here, we used a semiintact Drosophila melanogaster larva preparation and drugs targeting DA receptors and canonical second messenger pathways to identify signaling cascades that mediate the effect of DA on a myogenic heart. DA has a positive chronotropic effect that is mimicked by SKF38393 (type‐1 DA receptor agonist) and quinpirole (type‐2 DA receptor agonist). SCH23390 …

Effect Of Diurnal Fluctuating Versus Constant Temperatures On Germination Of 445 Species From The Eastern Tibet Plateau, Kun Liu, Jerry M. Baskin, Carol C. Baskin, Haiyan Bu, Guozhen Du, Miaojun Ma

Biology Faculty Publications

Germination response to fluctuating temperatures is a mechanism by which seeds detect gaps in vegetation canopies and depth of burial in soil, and it is very important for plants. Thus, studies on the effect of fluctuating temperature on germination at the community level are valuable for understanding community structure and biodiversity maintenance. We determined the effects of two alternating temperatures (5/25°C and 10/20°C) and one constant temperature (15°C) on seed germination of 445 species in a grassland community on the eastern Tibet Plateau. Seed mass was determined for each species, and data on habitat, type of life cycle, altitudinal distribution …

White-Tailed Deer (Odocoileus Virginianus) Positively Affect The Growth Of Mature Northern Red Oak (Quercus Rubra) Trees., R W. Lucas, R Salguero-Gomez, D B. Cobb, Bonnie G. Waring, F Anderson, W J. Mcshea, B B. Casper

Biology Faculty Publications

Understanding and predicting the effects of deer (Cervidae) on forest ecosystems present significant challenges in ecosystem ecology. Deer herbivory can cause large changes in the biomass and species composition of forest understory plant communities, including early life-cycle trees (i.e., seedlings and saplings). Such changes can impact juvenile to adult transitions and the future age structure and species composition of mature forests. Changes to understory vegetation also impact flow of energy and nutrients in forest ecosystems. Studies examining the influence of deer on mature trees, however, are rare and rely on extrapolating effects from early life cycle stages of trees. We …

Variation In Salamander Tail Regeneration Is Associated With Genetic Factors That Determine Tail Morphology, Gareth J. Voss, D. Kevin Kump, John A. Walker, S. Randal Voss

Biology Faculty Publications

Very little is known about the factors that cause variation in regenerative potential within and between species. Here, we used a genetic approach to identify heritable genetic factors that explain variation in tail regenerative outgrowth. A hybrid ambystomatid salamander (Ambystoma mexicanum x A. andersoni) was crossed to an A. mexicanum and 217 offspring were induced to undergo metamorphosis and attain terrestrial adult morphology using thyroid hormone. Following metamorphosis, each salamander’s tail tip was amputated and allowed to regenerate, and then amputated a second time and allowed to regenerate. Also, DNA was isolated from all individuals and genotypes were …

The Distribution Of Fruit And Seed Toxicity During Development For Eleven Neotropical Trees And Vines, Noelle G. Beckman

Biology Faculty Publications

Secondary compounds in fruit mediate interactions with natural enemies and seed dispersers, influencing plant survival and species distributions. The functions of secondary metabolites in plant defenses have been well-studied in green tissues, but not in reproductive structures of plants. In this study, the distribution of toxicity within plants was quantified and its influence on seed survival was determined in Central Panama. To investigate patterns of allocation to chemical defenses and shifts in allocation with fruit development, I quantified variation in toxicity between immature and mature fruit and between the seed and pericarp for eleven species. Toxicity of seed and pericarp …

Redbuds Similar Around The World, W. John Hayden

Biology Faculty Publications

Like music, one of the hallmarks of biodiversity is theme and variation. Redbuds—species of the genus Cercis— from around the world illustrate this analogy well. Because all redbud species conform to a certain morphological theme, anyone familiar with one particular species of redbud should be able to recognize without hesitation any other redbud species as a member of the genus Cercis. In brief, the redbud theme consists of broad, basally-lobed, leaves with pulvinar petiole thickenings, and pea-like red-purple (rarely white) flowers that may arise on small twigs or main trunks. In fact, these plants are so distinctive, it would …