Life Sciences Commons^™

Arabian Sea Response To Monsoon Variations, Raghu Murtugudde, Richard Seager, Prasad Thoppil

Faculty Publications

This study aims to quantify the impact of strong monsoons on the mixed layer heat budget in the Arabian Sea by contrasting forced ocean general circulation model simulations with composite strong and weak monsoon winds. Strong (weak) monsoons are defined as years with zonal component of the Somali Jet being greater (smaller) by more than a standard deviation of the long-term mean of the National Centers for Environmental Prediction reanalysis winds. Coastal upwelling is shown to be demonstrably stronger for strong monsoons leading to significant surface cooling, shallower thermoclines, and deeper mixed layers. A coupled ecosystem model shows that surface …

The Role Of Carcinine In Signaling At The Drosophila Photoreceptor Synapse, Brendan A. Gavin, Susan E. Arruda, Patrick J. Dolph

Dartmouth Scholarship

The Drosophila melanogaster photoreceptor cell has long served as a model system for researchers focusing on how animal sensory neurons receive information from their surroundings and translate this information into chemical and electrical messages. Electroretinograph (ERG) analysis of Drosophila mutants has helped to elucidate some of the genes involved in the visual transduction pathway downstream of the photoreceptor cell, and it is now clear that photoreceptor cell signaling is dependent upon the proper release and recycling of the neurotransmitter histamine. While the neurotransmitter transporters responsible for clearing histamine, and its metabolite carcinine, from the synaptic cleft have remained unknown, a …

A Quantitative Synthesis Of The Medicinal Ethnobotany Of The Malinké Of Mali And The Asháninka Of Peru, With A New Theoretical Framework, Nathaniel Bletter

Publications and Research

Background: Although ethnomedically and taxonomically guided searches for new medicinal plants can improve the percentage of plants found containing active compounds when compared to random sampling, ethnobotany has fulfilled little of its promise in the last few decades to deliver a bounty of new, laboratory-proven medicinal plants and compounds. It is quite difficult to test, isolate, and elucidate the structure and mechanism of compounds from the plethora of new medicinal plant uses described each year with limited laboratory time and resources and the high cost of clinical trials of new drug candidates.

Methods: A new quantitative theoretical framework of mathematical …

Lichens Of Pine Hill, A Peridotite Outcrop In Eastern North America, Tanner B. Harris, Fred C. Olday, Nishanta Rajakaruna

Biological Sciences

Despite a large body of work on the serpentine-substrate effect on vascular plants, little work has been undertaken to describe lichen communities growing on serpentine soils derived from peridotite and other ultramafic rocks. Most such work has been conducted in Europe and western North America. Only one study to date has examined the lichen flora of an ultramafic outcrop in eastern North America. The current paper examines the lichen flora of a peridotite outcrop from Deer Isle, Hancock County, Maine, U.S.A. The lichen flora is presented along with relevant ecological and geochemical data. Sixty-three species were found, comprising 35 genera. …

The Ecological Boundaries Of Six Carolina Bays: Community Composition And Ecotone Distribution, Lorrie Laliberte, James O. Luken, John J. Hutchens Jr., Kevin S. Godwin

Biology

Community and environmental gradients within the ecological boundaries of Carolina bay wetlands may provide important information on the interaction between Carolina bays and associated uplands, and may also provide guidance for improved management. We established twelve 30-m transects on the sloping rims of each of six Carolina bays in northeastern South Carolina to characterize the community gradient, as well as important environmental factors producing this gradient. Mid-points of the transects were placed on jurisdictional wetland boundaries. Hydrology, soil properties, and plant species composition were measured within these transects. On average, transects included an elevation change of 0.6 m that corresponded …

Pattern Analysis Of Microtubule-Polymerizing And -Depolymerizing Agent Combinations As Cancer Chemotherapies, Carol A. Heckman, S. O. Uppal, Y. Li, E. Wendt, M. L. Cayer, J. Barnes, D. Conway, N. Boudreau

Biological Sciences Faculty Publications

Subcellular distribution of mass can be analyzed by a technique that involves culturing cells on interferometers and digitizing their interference contours. Contour sampling resulted in 102 variables per cell, which were predictors of oncogenic transformation. Cell phenotypes can be deconstructed by use of latent factors, which represent the covariance of the real variables. The reversal of the cancertype phenotype by a combination of microtubule- stabilizing and -depolymerizing agents was described previously. The implications of these results have been explored by clinicians who treated patients with the combination of docetaxel and vinorelbine (Navelbine®). The current study was performed to determine the …

Vertebrate Osmoregulation: A Student Laboratory Exercise Using Teleost Fish, Bernard Rees

Biological Sciences Faculty Publications

Anaerobic metabolism is recruited in vertebrates under conditions of intense exercise or lowered environmental oxygen availability (hypoxia), typically resulting in the accumulation of lactate in blood and tissues. Lactate will be cleared over time after the reoxygenation of tissues, eventually returning to control levels. Here, we present a laboratory exercise developed as part of an upper-level vertebrate physiology class that demonstrates the effects of exercise and hypoxia exposure on blood lactate in fish and the subsequent decrease in lactate during recovery. Typically, the results obtained by students demonstrate that both treatments cause significant increases in blood lactate concentrations (two to …

Fundulus As The Premier Teleost Model In Environmental Biology: Opportunities For New Insights Using Genomics, Bernard Rees

Biological Sciences Faculty Publications

A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these …

Expression And Characterization Of The Flocculin Flo11/Muc1, A Yeast Mannoprotein With Homotypic Properties Of Adhesion, Li Li Ph.D., Lois M. Douglas, Yang Yang, A M. Dranginis

Faculty Works: Biology, Chemistry, and Environmental Studies

The Flo11/Muc1 flocculin has diverse phenotypic effects. Saccharomyces cerevisiae cells of strain background Σ1278b require Flo11p to form pseudohyphae, invade agar, adhere to plastic, and develop biofilms, but they do not flocculate. We show that S. cerevisiae var. diastaticusstrains, on the other hand, exhibit Flo11-dependent flocculation and biofilm formation but do not invade agar or form pseudohyphae. In order to study the nature of the Flo11p proteins produced by these two types of strains, we examined secreted Flo11p, encoded by a plasmid-borne gene, in which the glycosylphosphatidylinositol anchor sequences had been replaced by a histidine tag. A protein of …

Diatom Species Composition And Ecology Of The Animas River Watershed, Colorado, Usa, Gerald V. Sgro, John B. Poole, Jeffrey R. Johansen

Biology

The diatom flora of selected sites in the Animas River Watershed, San Juan County, Colorado, was studied. Eighty diatom taxa were identified from 10 sites: 8 sites on the Animas River and 1 site each on the Cement and Cascade tributaries. The sample diatom abundance was dominated by Achnanthidium minutissimum, Encyonema silesiacum, Aulacoseira distans, Hannaea arcus, and Diatoma mesodon. The presence of teratologic specimens of Fragilaria and Achnanthidium in the samples indicated the possibility of metals contamination. Diatom diversity was low and Lange-Bertalot pollution index scores indicated little organic pollution evidenced from diatom composition. There was evidence that diatom composition …

Most Caenorhabditis Elegans Micrornas Are Individually Not Essential For Development Or Viability, Eric A. Miska, Ezequiel Alvarez-Saavedra, Allison L. Abbott, Nelson C. Lau, Andrew B. Hellman, Shannon M. Mcgonagle, David P. Bartel, Victor R. Ambros, H. Robert Horvitz

Biological Sciences Faculty Research and Publications

MicroRNAs (miRNAs), a large class of short noncoding RNAs found in many plants and animals, often act to post-transcriptionally inhibit gene expression. We report the generation of deletion mutations in 87 miRNA genes in Caenorhabditis elegans, expanding the number of mutated miRNA genes to 95, or 83% of known C. elegans miRNAs. We find that the majority of miRNAs are not essential for the viability or development of C. elegans, and mutations in most miRNA genes do not result in grossly abnormal phenotypes. These observations are consistent with the hypothesis that there is significant functional redundancy among miRNAs …

The Emergence Of Sex, Ursula Goodenough

Biology Faculty Publications & Presentations

Biological traits, the foci of natural selection, are by definition emergent from the genes, proteins, and other “nothing-buts” that constitute them. Moreover, and with the exception of recently emergent “spandrels,” each can be accorded a teleological dimension—each is “for” some purpose conducive to an organism's continuation. Sex, which is “for” the generation of recombinant genomes, may be one of the most ancient and ubiquitous traits in biology. In the course of its evolution, many additional traits, such as gender and nurture, have emerged. Patterns of sexual exchange are the basis for patterns of biological evolution and are central to the …

Changes In Shell Morphology Of Elimia Comalensis (Gastropoda: Pleuroceridae) From The Edwards Plateau, Texas, Russell L. Minton, Scott A. Reese, Kim Swanger, Kathryn E. Perez, David M. Hayes

Biology Faculty Publications and Presentations

Species in the pleurocerid genus Elimia are important components of freshwater systems in the eastern United States, but little is known about their natural history. Using dual-simultaneous linear regression and principal components analyses, we show patterns of morphological change in two populations of E. comalensis from the Edwards Plateau, Texas. Both populations had similar rates of change for all shell measurements analyzed, and both showed similar decreases in growth as total length of shell increased. However, the size at which growth slowed was different between populations, and small shells tended to have a consistent shape, while larger shells were more …

Quantitative Dissection Of Clone-Specific Growth Rates In Cultured Malaria Parasites, Heather B. Reilly Ayala, Hongjian Wang, John A. Steuter, Anastasia M. Marx, Michael T. Ferdig

Faculty Publications - Department of Biological & Molecular Science

Measurement of parasite proliferation in cultured red blood cells underpins many facets of malaria research, from drug sensitivity assays to assessing the impact of experimentally altered genes on parasite growth, virulence, and fitness. Pioneering efforts to grow Plasmodium falciparum in cultured red blood cells revolutionized malaria research and spurred the development of semi-high throughput growth assays using radio-labeled hypoxanthine, an essential nucleic acid precursor, as a reporter of whole-cycle proliferation (Trager and Jensen, 1976; Desjardins et al., 1979). Use of hypoxanthine (Hx) and other surrogate readouts of whole-cycle proliferation remains the dominant choice in malaria research. While amenable to high-throughput …

Occurrence And Biological Effect Of Exogenous Steroids In The Elkhorn River, Nebraska, Usa, Alan S. Kolok, Daniel D. Snow, Satomi Kohno, Marlo K. Sellin, Louis J. Guillette Jr.

Biology Faculty Publications

Recent studies of surface waters in North America, Japan, and Europe have reported the presence of steroidogenic agents as contaminants. The current study has three objectives: 1) to determine if steroidogenic compounds are present in the Elkhorn River, 2) to determine if sediments collected from the Elkhorn River can act as a source of steroidogenic compounds to aquatic organisms, and 3) to determine if site-specific biological effects are apparent in the hepatic gene expression of fathead minnows. Evidence was obtained using three approaches: 1) deployment of polar organic chemical integrative samplers (POCIS), 2) deployment of caged fathead minnows, and 3) …

Compromised Weaponry Enhances Crayfish Tailflipping, Sandra Y. Espinoza, Zen Faulkes

Biology Faculty Publications and Presentations

As a defense strategy, many crustaceans perform one of two well described stereotyped single fast tailflips (~6 ms in adult crayfish), which are triggered by a neural circuit that includes medial giant interneurons (MG) and lateral giant interneurons (LG). Tailflips can also occur without these giant interneurons firing, however; these non-giant tailflips are variable, repetitive, and significantly longer (~150 ms). Previous work showed that crayfish exposed to natural stimulus respond with a non-giant tailflip significantly faster than when presented with an artificial stimulus and that complete removal of claws lowered tailflipping threshold. We tested whether compromising weapons would influence tailflipping. …

Cold Responsive Earli1 Type Hyprps Improve Freezing Survival Of Yeast Cells And Form Higher Order Complexes In Plants, Yi Zhang, Michael Schläppi

Biological Sciences Faculty Research and Publications

Plants have large families of proteins sharing a conserved eight-cysteine-motif (8CM) domain. The biological functions of these proteins are largely unknown. EARLI1 is a cold responsive Arabidopsis gene that encodes a hybrid proline-rich protein (HyPRP) with a three-domain architecture: a putative signal peptide at the N-terminus, a proline-rich domain (PRD) in the middle, and an 8CM domain at the C-terminus. We report here that yeast cells expressing different EARLI1 genes had significantly higher rates of freezing survival than empty-vector transformed controls. Arabidopsis plants with knocked down EARLI1 genes had an increased tendency for freezing-induced cellular damage. EARLI1-GFP Fluorescence in …

A Novel Zinc-Binding Domain Is Essential For Formation Of The Functional Junin Virus Envelope Glycoprotein Complex, Joanne York, Jack H. Nunberg

Biological Sciences Faculty Publications

The envelope glycoprotein of the Junin arenavirus (GP-C) mediates entry into target cells through a pH-dependent membrane fusion mechanism. Unlike other class I viral fusion proteins, the mature GP-C complex retains a cleaved, 58-amino-acid signal peptide (SSP) as an essential subunit, required both for trafficking of GP-C to the cell surface and for the activation of membrane fusion. SSP has been shown to associate noncovalently in GP-C via the cytoplasmic domain (CTD) of the transmembrane fusion subunit G2. In this report we investigate the molecular basis for this intersubunit interaction. We identify an invariant series of six cysteine and histidine …

Development Of New Simple Sequence Repeat Markers For Pearl Millet, O. P. Yadav, S. E. Mitchell, A. Zamora, Theresa M. Fulton, Stephen Kresovich

Faculty Publications

No abstract provided.

Designation Of A Neotype For Leptodactylus Gracilis (Duméril And Bibron, 1840) (Amphibia: Leptodactylidae), Rafael O. De Sá, A. Dubois, A. Ohler

Biology Faculty Publications

The examination of the preserved specimens in the herpetological collection of the Museum National d'Histoire Naturelle, along with a review of the original literature, indicates that no extant specimen can be undoubtedly identified as the holotype of Leptodactylus gracilis (DumCri.l and Bibron, 1840). Furthermore, it revealed that the type locality recently assigned to this taxon is in error.

Species Invasion Shifts The Importance Of Predator Dependence, Blaine D. Griffen, David G. Delaney

Faculty Publications

The strength of interference between foraging individuals can influence per capita consumption rates, with important consequences for predator and prey populations and system stability. Here we demonstrate how the replacement of a previously established invader, the predatory crab Carcinus maenas, by the recently invading predatory crab Hemigrapsus sanguineus shifts predation from a species that experiences strong predator interference (strong predator dependence) to one that experiences weak predator interference (weak predator dependence). We demonstrate using field experiments that differences in the strength of predator dependence persist for these species both when they forage on a single focal prey species only (the …

A Statistical Appraisal Of Disproportional Versus Proportional Microbial Source Tracking Libraries, Brian J. Robinson, Kerry J. Ritter, Rudolph D. Ellender

Faculty Publications

Library-based microbial source tracking (MST) can assist in reducing or eliminating fecal pollution in waters by predicting sources of fecal-associated bacteria. Library-based MST relies on an assembly of genetic or phenotypic "fingerprints" from pollution-indicative bacteria cultivated from known sources to compare with and identify fingerprints of unknown origin. The success of the library-based approach depends on how well each source candidate is represented in the library and which statistical algorithm or matching criterion is used to match unknowns. Because known source libraries are often built based on convenience or cost, some library sources may contain more representation than others. Depending …

Evalution Of The Efficacy Of The Photosystem Ii Inhibitor Dcmu In Periphyton And Its Effects On Nontarget Microorganisms And Extracellular Enzymatic Reactions, Steven N. Francoeur, Audrey C. Johnson, Kevin A. Kuehn, Robert K. Neely

Faculty Publications

We examined the efficacy of the photosystem II inhibitor 3-(3,4-diclorophenyl)-1,1-dimethyl urea (DCMU) for inhibition of algal photosynthesis in periphyton associated with submerged decomposing litter of Typha angustifolia. We also investigated the possible nontarget effects of DCMU exposure on heterotrophic microorganisms (i.e., bacteria and fungi) and extracellular enzyme activity associated with decaying litter. Standing-dead Typha leaf litter was submerged for 34 and 73 d, returned to the laboratory, and used for controlled laboratory experiments that examined the effect of DCMU on algal ([¹⁴C]bicarbonate, pulse-amplitude modulated fluorometry), bacterial ([³H]leucine), and fungal ([¹⁴C]acetate) production. Simultaneous assays …

Mechanisms Of Covalent Self-Assembly Of The Azoarcus Ribozyme From Four Fragment Oligonucleotides, Will E. Draper, Eric John Hayden, Niles Lehman

Chemistry Faculty Publications and Presentations

RNA oligomers of length 40–60 nt can self-assemble into covalent versions of the Azoarcus group I intron ribozyme. This process requires a series of recombination reactions in which the internal guide sequence of a nascent catalytic complex makes specific interactions with a complement triplet, CAU, in the oligomers. However, if the CAU were mutated, promiscuous self-assembly may be possible, lessening the dependence on a particular set of oligomer sequences. Here, we assayed whether oligomers containing mutations in the CAU triplet could still self-construct Azoarcus ribozymes. The mutations CAC, CAG, CUU and GAU all inhibited self-assembly to some degree, but did …

Bioluminescence In A Complex Coastal Environment: 2. Prediction Of Bioluminescent Source Depth From Spectral Water-Leaving Radiance, Matthew J. Oliver, Mark A. Moline, Curtis D. Mobley, Lydia Sundman, Oscar M.E. Schofield

Biological Sciences

Many bioluminescence observations are made from the ocean's surface. However, the depth of the bioluminescent source is difficult to estimate on the basis of surface observations alone, given the variable light attenuation of unknown concentrations of water column constituents such as phytoplankton, colored dissolved organic matter, and detritus. Part 1 of this paper showed that bioluminescent water-leaving radiance signals are detectable, even in extremely turbid and dynamic coastal waters. Here, in part 2 of this paper, we analyze the water-leaving radiance patterns of bioluminescence modeled by HydroLight 4.2 to determine if the depth of the bioluminescent source can be estimated …

Evidence Of Compromised Blood-Spinal Cord Barrier In Early And Late Symptomatic Sod1 Mice Modeling Als, Svitlana N. Garbuzova-Davis, Samuel Saporta, Edward M. Haller, Irina Kolomey, Steven P. Bennett, Huntington Potter, Paul R. Sanberg

Integrative Biology Faculty and Staff Publications

Background: The blood-brain barrier (BBB), blood-spinal cord barrier (BSCB), and blood-cerebrospinal fluid barrier (BCSFB) control cerebral/spinal cord homeostasis by selective transport of molecules and cells from the systemic compartment. In the spinal cord and brain of both ALS patients and animal models, infiltration of T-cell lymphocytes, monocyte-derived macrophages and dendritic cells, and IgG deposits have been observed that may have a critical role in motor neuron damage. Additionally, increased levels of albumin and IgG have been found in the cerebrospinal fluid in ALS patients. These findings suggest altered barrier permeability in ALS. Recently, we showed disruption of the BBB and …

Temperature Effects On Metabolic Rate Of Juvenile Pacific Bluefin Tuna Thunnus Orientalis, Jason M. Blank, Jeffery M. Morrissette, Charles J. Farwell, Mathew Price, Robert J. Schallert, Barbara A. Block

Biological Sciences

Pacific bluefin tuna inhabit a wide range of thermal environments across the Pacific ocean. To examine how metabolism varies across this thermal range, we studied the effect of ambient water temperature on metabolic rate of juvenile Pacific bluefin tuna, Thunnus thynnus, swimming in a swim tunnel. Rate of oxygen consumption (M_O2) was measured at ambient temperatures of 8–25°C and swimming speeds of 0.75–1.75 body lengths (BL) s^–1. Pacific bluefin swimming at 1 BL s^–1 per second exhibited a U-shaped curve of metabolic rate vs ambient temperature, with a thermal minimum zone between …

Regeneration Of Retinotectal Projections After Optic Tectum Removal In Adult Newts, Mitsumasa Okamoto, Hatsuki Ohsawa, Toshinori Hayashi, Katsushi Owaribe, Panagiotis A. Tsonis

Biology Faculty Publications

Purpose: When injured, the adult newt possesses the remarkable capability to regenerate tissues and organs with return of function and physiology. One example is the newt eye, in which regeneration can restore normal vision if the retina or lens has been removed. We wanted to examine how the retinotectal projections regenerate after removal of the brain’s optic tectum and establish this animal as a model for retinal projection as well as a central nervous system regeneration model.

Structural Biology: A Receptor Unlocked, Stephen R. Sprang

Biological Sciences Faculty Publications

No abstract provided.

Conservation Implications Of The Reproductive Biology Of The Endangered Vine Ipomoea Microdactyla Griseb. (Convolvulaceae), John H. Geiger

FIU Electronic Theses and Dissertations

A plant’s reproductive biology exerts a significant influence on both population persistence within changing environments and successful establishment of new populations. However, the interaction between extrinsic (i.e. ecological) and intrinsic (i.e. genetic) factors also is an important driver of demographic performance for plant populations. It is light of this that I performed a multidisciplinary investigation of the breeding system, seed and seedling establishment dynamics, and population genetic structure of the endangered Caribbean vine Ipomoea microdactyla Griseb. (Convolvulaceae). The results from the breeding system study show individuals from Florida, USA and Andros Island, Bahamas to be self-incompatible. Plants from the two …