Life Sciences Commons^™

Betting & Hierarchy In Paleontology, Leonard Finkelman

Faculty Publications

In his Rock, Bone, and Ruin: An Optimist’s Guide to the Historical Sciences, Adrian Currie argues that historical scientists should be optimistic about success in reconstructing the past on the basis of future research. This optimism follows in part from examples of success in paleontology. I argue that paleontologists’ success in these cases is underwritten by the hierarchical nature of biological information: extinct organisms have extant analogues at various levels of taxonomic, ecological, and physiological hierarchies, and paleontologists are adept at exploiting analogies within one informational hierarchy to infer information in another. On this account, fossils serve the role …

Diversity As Opportunity: Insights From 600 Million Years Of Ahr Evolution, Rebeka R. Merson, Mark E. Hahn, Sibel I. Karchner

Faculty Publications

The aryl hydrocarbon receptor (AHR) was for many years of interest only to pharmacologists and toxicologists. However, this protein has fundamental roles in biology that are being revealed through studies in diverse animal species. The AHR is an ancient protein. AHR homologs exist in most major groups of modern bilaterian animals, including deuterostomes (chordates, hemichordates, echinoderms) and the two major clades of protostome invertebrates [ecdysozoans (e.g. arthropods and nematodes) and lophotrochozoans (e.g. molluscs and annelids)]. AHR homologs also have been identified in cnidarians such as the sea anemone Nematostella and in the genome of Trichoplax, a placozoan. Bilaterians, cnidarians, and …

Evotext: A New Tool For Analyzing The Biological Sciences, Grant Ramsey, Charles H. Pence

Faculty Publications

We introduce here evoText, a new tool for automated analysis of the literature in the biological sciences. evoText contains a database of hundreds of thousands of journal articles and an array of analysis tools for generating quantitative data on the nature and history of life science, especially ecology and evolutionary biology. This article describes the features of evoText, presents a variety of examples of the kinds of analyses that evoText can run, and offers a brief tutorial describing how to use it.

Streamwise Vortices Destabilize Swimming Bluegill Sunfish, Anabela Maia, Alex P. Sheltzer, Eric D. Tytell

Faculty Publications

In their natural environment, fish must swim stably through unsteady flows and vortices, including vertical vortices, typically shed by posts in a flow, horizontal cross-flow vortices, often produced by a step or a waterfall in a stream, and streamwise vortices, where the axis of rotation is aligned with the direction of the flow. Streamwise vortices are commonly shed by bluff bodies in streams and by ships’ propellers and axial turbines, but we know little about their effects on fish. Here, we describe how bluegill sunfish use more energy and are destabilized more often in flow with strong streamwise vorticity. The …

Trace Metals (Cu, Zn, Cd And Pb) In Juvenile Fish From Estuarine Nurseries Along The Portugese Coast, Rita P. Vasconcelos, Patrick Reis-Santos, Anabela Maia, Miguel Ruano, Maria J. Costa Universidade De Lisboa

Faculty Publications

Organic and inorganic pollution can impact organisms directly and affect condition, growth and survival of juvenile fish which use estuaries as nurseries, and thereby affect marine adult populations quantitatively and qualitatively. Trace element contamination (Cu, Zn, Cd, Pb) in juveniles of commercial fish Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax collected in putative nurseries of the main Portuguese estuaries (with diverse intensities and sources of anthropogenic pressures) was determined via atomic absorption spectrometry. Contamination was significantly different among species. Similar levels of contamination were found among estuaries, except for D. vulgaris. Cu and Zn concentrations …

Weeds In The Flower Garden: An Exploration Of Plagiarism In Graduate Students’ Research Proposals And Its Connection To Enculturation, Esl, And Contextual Factors, Joanna Gilmore, Denise Strickland, Briana Eileen Timmerman, Michelle Maher, David Feldon

Faculty Publications

Existing literature provides insight into the nature and extent of plagiarism amongst undergraduate students (e.g., Ellery, 2008; Parameswaran & Devi, 2006; Selwyn, 2008). Plagiarism amongst graduate students is relatively unstudied, however, and the existing data are largely based on self-reports. This study investigated the rates and potential causes of plagiarism amongst graduate students in master’s and doctoral programmes in science, technology, engineering, mathematics, and science or mathematics education by examining actual research proposals written by graduate students. Results indicate that plagiarism is a prevalent issue at each of the three university sites sampled and across all of the investigated disciplines. …

Genomic Organization And Molecular Phylogenies Of The Beta (Β) Keratin Multigene Family In The Chicken (Gallus Gallus) And Zebra Finch (Taeniopygia Guttata): Implications For Feather Evolution, Matthew J. Greenwold, Roger H. Sawyer

Faculty Publications

Background: The epidermal appendages of reptiles and birds are constructed of beta (β) keratins. The molecularphylogeny of these keratins is important to understanding the evolutionary origin of these appendages, especially feathers. Knowing that the crocodilian β-keratin genes are closely related to those of birds, the published genomes ofthe chicken and zebra finch provide an opportunity not only to compare the genomic organization of their β- keratins,but to study their molecular evolution in archosaurians.

Results: The subfamilies (claw, feather, feather-like, and scale) of β-keratin genes are clustered in the same 5' to 3' orderon microchromosome 25 in chicken and zebra finch, …

Development Of A ‘Universal’ Rubric For Assessing Undergraduates’ Scientific Reasoning Skills Using Scientific Writing, Briana Eileen Timmerman, Denise Strickland, Robert L. Johnson, John R. Payne

Faculty Publications

We developed a rubric for measuring students’ ability to reason and write scientifically. The Rubric for Science Writing (Rubric) was tested in a variety of undergraduate biology laboratory courses (total n = 142 laboratory reports) using science graduate students (teaching assistants) as raters. Generalisability analysis indicates that the Rubric provides a reliable measure of students’ abilities (g = 0.85) in these conditions. Comparison of student performance in various biology classes indicated that some scientific skills are more challenging for students to develop than others and identified a number of previously unappreciated gaps in the curriculum. Our findings suggest that use …

Organismal Climatology: Analyzing Environmental Variability At Scales Relevant To Physiological Stress, Brian Helmuth, Bernardo R. Broitman, Lauren Yamane, Sarah E. Gilman, Katharine Mach, K. A.S. Mislan, Mark W. Denny

Faculty Publications

Predicting when, where and with what magnitude climate change is likely to affect the fitness, abundance and distribution of organisms and the functioning of ecosystems has emerged as a high priority for scientists and resource managers. However, even in cases where we have detailed knowledge of current species’ range boundaries, we often do not understand what, if any, aspects of weather and climate act to set these limits. This shortcoming significantly curtails our capacity to predict potential future range shifts in response to climate change, especially since the factors that set range boundaries under those novel conditions may be different …

An Intertidal Sea Star Adjusts Thermal Inertia To Avoid Extreme Body Temperatures, Sylvain Pincebourde, Eric Sanford, Brian Helmuth

Faculty Publications

The body temperature of ectotherms is influenced by the interaction of abiotic conditions, morphology, and behavior. Although organisms living in different thermal habitats may exhibit morphological plasticity or move from unfavorable locations, there are few examples of animals adjusting their thermal properties in response to short-term changes in local conditions. Here, we show that the intertidal sea star Pisaster ochraceus modulates its thermal inertia in response to prior thermal exposure. After exposure to high body temperature at low tide, sea stars increase the amount of colder than-air fluid in their coelomic cavity when submerged during high tide, resulting in a …

Interaction Of Fish Aryl Hydrocarbon Receptor Paralogs (Ahr1 And Ahr2) With The Retinoblastoma Protein, Rebeka R. Merson, Sibel I. Karchner, Mark E. Hahn

Faculty Publications

The aryl hydrocarbon receptor (AHR) mediates the toxic effects of 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD) and related compounds. In some mammalian cell lines, TCDD induces G1 cell cycle arrest, which depends on an interaction between the AHR and the retinoblastoma tumor suppressor (RB). Mammals possess one AHR, whereas fishes possess two or more AHR paralogs that differ in the domains important for AHR-RB interactions in mammals. To test the hypothesis that fish AHR paralogs differ in their ability to interact with RB, we cloned RB cDNA from Atlantic killifish, Fundulus heteroclitus, and studied the interactions of killifish RB protein with killifish AHR1 and …

Faculty Should Consider Peer Review As A Means Of Improving Students' Scientific Reasoning Skill, Briana Eileen Timmerman, Denise Strickland

Faculty Publications

The following article provides highlights of a larger body of work on the impact of peer review on undergraduate biology students’ scientific reasoning, scientific writing and attitudes. Results suggest that undergraduates, even freshman can be effective peer reviewers and that peer review improves scientific writing, content knowledge, and scientific reasoning skills. Students report peer review to be a beneficial experience both within the course and in terms of helping them to develop as aspiring scientists. Science faculty are therefore encouraged to consider incorporating peer review as a regular part of instruction.

From Cells To Coastlines: How Can We Use Physiology To Forecast The Impacts Of Climate Change?, Brian Helmuth

Faculty Publications

The interdisciplinary fields of conservation physiology, macrophysiology, and mechanistic ecological forecasting have recently emerged as means of integrating detailed physiological responses to the broader questions of ecological and evolutionary responses to global climate change. Bridging the gap between large-scale records of weather and climate (as measured by remote sensing platforms, buoys and ground-based weather stations) and the physical world as experienced by organisms (niche-level measurements) requires a mechanistic understanding of how ‘environmental signals’ (parameters such as air, surface and water temperature, food availability, water flow) are translated into signals at the scale of the organism or cell (e.g. body temperature, …

Lis1 And Ndel1 Influence The Timing Of Nuclear Envelope Breakdown In Neural Stem Cells, Sachin Hebbar, Mariano T. Mesngon, Aimee M. Guillotte, Bhavim Desai, Ramses Ayala, Deanna S. Smith

Faculty Publications

Lis1 and Ndel1 are essential for animal development. They interact directly with one another and with cytoplasmic dynein. The developing brain is especially sensitive to reduced Lis1 or Ndel1 levels, as both proteins influence spindle orientation, neural cell fate decisions, and neuronal migration. We report here that Lis1 and Ndel1 reduction in a mitotic cell line impairs prophase nuclear envelope (NE) invagination (PNEI). This dyneindependent process facilitates NE breakdown (NEBD) and occurs before the establishment of the bipolar spindle. Ndel1 phosphorylation is important for this function, regulating binding to both Lis1 and dynein. Prophase cells in the ventricular zone (VZ) …

Peer Review In An Undergraduate Biology Curriculum: Effects On Students’ Scientific Reasoning, Writing And Attitudes, Briana Eileen Timmerman

Faculty Publications

Scientific reasoning and writing skills are ubiquitous processes in science and therefore common goals of science curricula, particularly in higher education. Providing the individualized feedback necessary for the development of these skills is often costly in terms of faculty time, particularly in large science courses common at research universities. Past educational research literature suggests that the use of peer review may accelerate students’ scientific reasoning skills without a concurrent demand on faculty time per student. Peer review contains many elements of effective pedagogy such as peer-peer collaboration, repeated practice at evaluation and critical thinking, formative feedback, multiple contrasting examples, and …

Extracellular Stimuli Specifically Regulate Localized Levels Of Individual Neuronal Mrnas, Dianna E. Willis, Erna A. Van Niekerk, Yukio Sasaki, Mariano Mesngon, Tanuja T. Merianda, Gervan G. Williams, Marvin Kendall, Deanna S. Smith, Gary J. Bassell, Jeffery L. Twiss

Faculty Publications

Subcellular regulation of protein synthesis requires the correct localization of messenger RNAs (mRNAs) within the cell. In this study, we investigate whether the axonal localization of neuronal mRNAs is regulated by extracellular stimuli. By profiling axonal levels of 50 mRNAs detected in regenerating adult sensory axons, we show that neurotrophins can increase and decrease levels of axonal mRNAs. Neurotrophins (nerve growth factor, brainderived neurotrophic factor, and neurotrophin-3) regulate axonal mRNA levels and use distinct downstream signals to localize individual mRNAs. However, myelin-associated glycoprotein and semaphorin 3A regulate axonal levels of different mRNAs and elicit the opposite effect on axonal mRNA …

A Unified View Of Base Excision Repair, Karen H. Almeida, Robert W. Sobol

Faculty Publications

Base excision repair (BER) proteins act upon a significantly broad spectrum of DNA lesions that result from endogenous and exogenous sources. Multiple sub-pathways of BER (short-path or longpatch) and newly designated DNA repair pathways (e.g., SSBR and NIR) that utilize BER proteins complicate any comprehensive understanding of BER and its role in genome maintenance, chemotherapeutic response, neurodegeneration, cancer or aging. Herein, we propose a unified model of BER, comprised of three functional processes: Lesion Recognition/Strand Scission, Gap Tailoring and DNA Synthesis/Ligation, each represented by one or more multiprotein complexes and coordinated via the XRCC1/DNA Ligase III and PARP1 scaffold proteins. …

Linking Bacterioplankton Community Structures To Environmental State Variables And Phytoplankton Assemblages In Two South Carolina Salt Marsh Estuaries, Wes Johnson, Alan J. Lewitus, Madilyn Fletcher

Faculty Publications

Microorganisms are among the most important organisms to the ecology of salt marsh estuaries; however, fundamental questions regarding their distribution, environmental controls, and interactions with phytoplankton remain unanswered. We used denaturing gradient gel electrophoresis (DGGE) of bacterial rRNA genes and high performance liquid chromatography (HPLC) of phytoplankton photopigments to characterize planktonic communities from the Ashepoo, Combahee, and Edisto (ACE) Basin and North Inlet (NI) estuaries on the South Carolina coast, USA. Multivariate comparisons of the planktonic community profiles revealed that the 2 estuaries supported distinct bacterial communities. Furthermore, bacterial communities in both systems were partitioned into separate particle-associated (PA) and …

Ecological Fitting As A Determinant Of The Community Structure Of Platyhelminth Parasites Of Anurans, Daniel R. Brooks, Virginia León-Règagnon, Deborah Mclennan, Derek Zelmer

Faculty Publications

Host–parasite associations are assumed to be ecologically specialized, tightly coevolved systems driven by mutual modification in which host switching is a rare phenomenon. Ecological fitting, however, increases the probability of host switching, creating incongruences between host and parasite phylogenies, when (1) specialization on a particular host resource is a shared characteristic of distantly related parasites, and (2) the resource being tracked by the parasite is widespread among many host species. We investigated the effect of ecological fitting on structuring the platyhelminth communities of anurans from a temperate forest and grassland in the United States and tropical dry and wet forests …

Regulation Of Cytoplasmic Dynein Atpase By Lis1, Mariano T. Mesngon, Cataldo Tarricone, Sachin Hebbar, Aimee Guillotte, E. William Schmitt, Lorene Lanier, Andrea Musacchio, Stephen J. King, Deanna S. Smith

Faculty Publications

Mutations in Lis1 cause classical lissencephaly, a developmental brain abnormality characterized by defects in neuronal positioning.Over the last decade, a clear link has been forged between Lis1 and the microtubule motor cytoplasmic dynein. Substantial evidenceindicates that Lis1 functions in a highly conserved pathway with dynein to regulate neuronal migration and other motile events. Yeasttwo-hybrid studies predict that Lis1 binds directly to dynein heavy chains (Sasaki et al., 2000; Tai et al., 2002), but the mechanistic significance of this interaction is not well understood. We now report that recombinant Lis1 binds to native brain dynein and significantly increases the microtubule-stimulated enzymatic …

Photochemical Transformations Of Riverine Dissolved Organic Matter: Effects On Estuarine Bacterial Metabolism And Nutrient Demand, Erik M. Smith, Ronald Benner

Faculty Publications

By experimentally simulating the exposure of terrigenous dissolved organic matter (DOM) to sunlight during the mixing of river water and seawater in an estuary (St. Helena Sound, South Carolina), this study examined how photochemical alterations may affect both the magnitude and fate of DOM utilization by estuarine bacteria. In a series of experiments performed with water samples collected from 3 blackwater rivers draining into an estuary of the South Atlantic Bight (USA), exposure to light resulted in significant decreases in dissolved organic carbon (DOC) concentration and DOM absorption at 350 nm relative to dark controls. When these water samples were …

A Patch Hath Smaller Patches: Delineating Ecological Neighborhoods For Parasites, Derek Zelmer, John R. Seed

Faculty Publications

Use of the host individual as a boundary for parasite populations and communities provides an unambiguous spatial unit that is useful for pattern description, but this framework precludes consideration of the host landscape and within-host population dynamics. Recognizing host individuals as spatially and temporally complex landscapes requires modified concepts of parasite populations and communities. An outline of the currently accepted hierarchies of parasite populations and communities is provided on the basis of ecological neighborhoods that are delineated by discrete habitat patches or functional dynamics (or both), as opposed to host individuals. This parasite-based framework accommodates consideration of both within- and …

Individual Cell Growth Rates Of Marine Bacteria, Measured By Bromodeoxyuridine Incorporation, Koji Hamasaki, Richard A. Long, Farooq Azam

Faculty Publications

We tested the application of 5-bromo-2’-deoxyuridine (BrdU), a thymidine analogue that becomes incorporated into DNA during growth, to measure growth rates of individual marine bacteria cells. Immunocytochemical detection of BrdU incorporation into bacterial DNA has the potential for single-cell-based growth measurement. Optimized procedure for immunocytochemistry was applicable to 14 marine heterotrophic bacterial isolates belonging to g-proteobacteria, α-proteobacteria, Cytophaga-Flavobacterium-Bacteroides (CFB) group and Gram-positive bacteria. The relationship between cell-specific fluorescence intensity and specific growth rate was linearly correlated among CFB group isolates, which indicated a potential of the method for quantitative measurement. Analysis of the detection limit indicated …

Particle Removal Rates By The Mud Shrimp Upogebia Pugettensis, Its Burrow, And A Commensal Clam: Effects On Estuarine Phytoplankton Abundance, Blaine D. Griffen, Theodore H. Dewitt, Chris Langdon

Faculty Publications

The burrowing shrimp Upogebia pugettensis is an abundant intertidal invertebrate of Pacific Northwest, USA bays and estuaries where it lives commensally with the bivalve Cryptomya californica. Suspension-feeding activities by the shrimp and by its commensal clam, as well as particle settlement within the burrow, represent 3 different components that could remove phytoplankton from water drawn into shrimp burrows. These 3 components together comprise what we call the ‘U. pugettensis shrimp-burrow complex’. In laboratory experiments, we measured particle removal by each of these components. Our results indicated that U. pugettensis itself is responsible for filtering the majority of phytoplankton removed …

P-Limitation Of Respiration In The Sargasso Sea And Uncoupling Of Bacteria From P-Regeneration In Size-Fractionation Experiments, Ingrid Obernosterer, Nobu Kawasaki, Ronald Benner

Faculty Publications

Community respiration rates were measured in unfiltered seawater collected in the upper 75 m of the water column along a transect in the Sargasso Sea and at the Bermuda Atlantic Time-series Study (BATS) station (31° 50’ 00 N; 64° 10’ 00 W) during a cruise in June and July 2001. Community respiration rates in the upper 75 m of the water column averaged 1.1 ± 0.4 μM O₂ d^-1 and exhibited significant spatial and temporal variability. Concurrent determination of the heterotrophic and autotrophic community revealed no relationship between community respiration and the abundance of any of the major …

Microalgal-Meiofaunal Trophic Relationships In Muddy Intertidal Estuarine Sediments, James L. Pinckney, Kevin R. Carman, S. Elizabeth Lumsden, Sabrina N. Hymel

Faculty Publications

The determination of the primary factors controlling carbon (C) transfer rates in situ are a basic requirement for developing a mechanistic view of the processes that regulate benthic microbial community structure and function. In many estuarine ecosystems, the base of the food web is dominated by microalgal production; however, information on the quantitative relationships and process rates of meiofaunal grazers and benthic microalgal (BMA) producers is limited to a few habitats and short temporal scales. The primary objective of this study was to examine the trophic interactions between meiofaunal grazers and BMA producers to determine if grazing is a primary …

Simple, Compact Source For Low-Temperature Air Plasmas, D. P. Sheehan, J. Lawson, M. Sosa, Richard A. Long

Faculty Publications

A simple, compact source of low-temperature, spatially and temporally uniform air plasma using a Telsa induction coil driver is described. The low-power ionization discharge plasma is localized (2 cm X 0.5 cm X 0.1 cm) and essentially free of arc channels. A Teflon coated rolling cylindrical electrode and dielectric coated ground plate are essential to the source’s operation and allow flat test samples to be readily exposed to the plasma. The plasma is a copious source of ozone and nitrogen oxides. Its effects on various microbes are discussed.

Seasonal Niche Strategy Of The Bloom-Forming Dinoflagellate Heterocapsa Triquetra, R. W. Litaker, P. A. Tester, C. S. Duke, B. E. Kenney, James L. Pinckney, J. Ramus

Faculty Publications

Heterocapsa triquetra is one of the most common bloom-forming dinoflagellates found in estuaries and near shore regions around the world. This work examined the environmental factors associated with 3 separate wintertime H. triquetra blooms in the shallow tidally mixed Newport River estuary, North Carolina, USA. During 2 of the blooms in 1982 and 1983, the estuary was sampled from a fixed, single location every hour for 14 d. During the third study, the estuary was sampled at 9 fixed locations over its entire length each week from late December 1997 through March 1998. This time period included the formation and …

Estimating The Spatial Extent Of Bottom-Water Hypoxia And Habitat Degradation In A Shallow Estuary, Christopher P. Buzzelli, Richard A. Luettich Jr., Sean P. Powers, Charles H. Peterson, Jesse E. Mcninch, James L. Pinckney, Hans W. Paerl

Faculty Publications

Bottom-water hypoxia (≤ 2 mg 1^-1 dissolved oxygen [DO]) greatly modifies the benthic habitat of estuaries, depending upon spatial extent, duration, and frequency. Bottom-water hypoxia often develops under conditions of density stratification, which inhibits vertical mixing, and warm temperatures, which enhance biological oxygen demand. Long-term, mid-channel data from the Neuse River Estuary in North Carolina permitted evaluation of how stratification and temperature combined to affect DO concentrations at the bottom. Salinity stratification (DS) and water temperature (T) explained respectively 30 and 23% of the variance in bottom-water DO concentrations. The amount of salinity stratification required to induce bottom-water …

Thin Laser Light Sheet Microscope For Microbial Oceanography, Eran Fuchs, Jules S. Jaffe, Richard A. Long, Farooq Azam

Faculty Publications

Despite a growing need, oceanographers are limited by existing technological constrains and are unable to observe aquatic microbes in their natural setting. In order to provide a simple and easy to implement solution for such studies, a new Thin Light Sheet Microscope (TLSM) has been developed. The TLSM utilizes a well-defined sheet of laser light, which has a narrow (23 micron) axial dimension over a 1 mm x 1 mm field of view. This light sheet is positioned precisely within the depth of field of the microscope’s objective lens. The technique thus utilizes conventional microscope optics but replaces the illumination …