Life Sciences Commons^™

Photochemical And Microbial Alteration Of Dissolved Organic Matter In Temperate Headwater Streams Associated With Different Land Use, Randolph Chambers

Arts & Sciences Articles

Photochemical and microbial transformations of DOM were evaluated in headwater streams draining forested and human‐modified lands (pasture, cropland, and urban development) by laboratory incubations. Changes in DOC concentrations, DOC isotopic signatures, and DOM fluorescence properties were measured to assess the amounts, sources, ages, and properties of reactive and refractory DOM under the influence of photochemistry and/or bacteria. DOC in streams draining forest‐dominated watersheds was more photoreactive than in streams draining mostly human‐modified watersheds, possibly due to greater contributions of terrestrial plant‐derived DOC and lower amounts of prior light exposure in forested streams. Overall, the percentage of photoreactive DOC in stream …

Budding Yeast Protein Extraction And Purification For The Study Of Function, Interactions, And Post-Translational Modifications, Eva P. Szymanski, Oliver Kerscher

Arts & Sciences Articles

Homogenization by bead beating is a fast and efficient way to release DNA, RNA, proteins, and metabolites from budding yeast cells, which are notoriously hard to disrupt. Here we describe the use of a bead mill homogenizer for the extraction of proteins into buffers optimized to maintain the functions, interactions and post-translational modifications of proteins. Logarithmically growing cells expressing the protein of interest are grown in a liquid …

Integrated Carbon Budget Models For The Everglades Terrestrial-Coastal-Oceanic Gradient: Current Status And Needs For Inter-Site Comparisons., Randolph Chambers

Arts & Sciences Articles

Recent studies suggest that coastal ecosystems can bury significantly more C than tropical forests, indicating that continued coastal development and exposure to sea level rise and storms will have global biogeochemical consequences. e Florida Coastal Everglades Long Term Ecological Research (FCE LTER) site provides an excellent subtropical system for examining carbon (C) balance because of its exposure to historical changes in freshwater distribution and sea level rise and its history of significant long-term carbon-cycling studies. FCE LTER scientists used net ecosystem C balance and net ecosystem exchange data to estimate C budgets

for riverine mangrove, freshwater marsh, and seagrass meadows, …

Selective Feeding On Nutrient-Rich Particles By Gizzard Shad Dorosoma Cepedianum Does Not Involve Mechanical Sorting, M. K. Heidman, L. L. Holley, Randolph Chambers, S. Laurie Sanderson

Arts & Sciences Articles

Previous field and laboratory studies have concluded that suspension-feeding detritivorous fish such as gizzard shad Dorosoma cepedianum selectively ingest nutrient-rich particles using either mechanical sorting within the oropharyngeal cavity or behavioral selectivity within the environment, but none have distinguished between these hypothesized selection mechanisms. To determine whether mechanical selectivity occurs within the oropharyngeal cavity, gizzard shad were fed particles of standardized size but different carbon and nitrogen content in homogeneous particle suspensions vs. non-homogeneous particle distributions. By comparing foregut and epibranchial organ contents with the particles available in a homogeneous suspension, we demonstrated that the fish did not use mechanical …

Multiple Novel Signals Mediate Thyroid Hormone Receptor Nuclear Import And Export, Manohara S. Mavinakere, Jeremy M. Powers, Kelly S. Subramanian, Vincent R. Roggero, Lizabeth A. Allison

Arts & Sciences Articles

Thyroid hormone receptor (TR) is a member of the nuclear receptor superfamily that shuttles between the cytosol and nucleus. The fine balance between nuclear import and export of TR has emerged as a critical control point for modulating thyroid hormone-responsive gene expression; however, sequence motifs of TR that mediate shuttling are not fully defined. Here, we characterized multiple signals that direct TR shuttling. Along with the known nuclear localization signal in the hinge domain, we identified a novel nuclear localization signal in the A/B domain of thyroid hormone receptor a1 that is absent in thyroid hormone receptor B1 and inactive …

Recruitment Of The Oncoprotein V-Erba To Aggresomes, Cornelius Bondzi, Abigail M. Brunner, Michelle R. Munyikwa, Crystal D. Conner, Et Al., Vincent R. Roggero, Lizabeth A. Allison

Arts & Sciences Articles

Aggresome formation, a cellular response to misfolded protein aggregates, is linked to cancer and neurodegenerative disorders. Previously we showed that Gag-v-ErbA (v-ErbA), a retroviral variant of the thyroid hormone receptor (TRα1), accumulates in and sequesters TRα1 into cytoplasmic foci. Here, we show that foci represent v-ErbA targeting to aggresomes. v-ErbA colocalizes with aggresomal markers, proteasomes, hsp70, HDAC6, and mitochondria. Foci have hallmark characteristics of aggresomes: formation is microtubule-dependent, accelerated by proteasome inhibitors, and they disrupt intermediate filaments. Proteasome-mediated degradation is critical for clearance of v-ErbA and T3-dependent TRα1 clearance. Our studies highlight v-ErbA's complex mode of action: the oncoprotein is …

The Pseudophosphatase Mk-Styx Interacts With G3bp And Decreases Stress Granule Formation, Shanta D. Hinton, Michael P. Myers, Vincent R. Roggero, Lizabeth A. Allison, Nicholas K. Tonks

Arts & Sciences Articles

MK-STYX [MAPK (mitogen-activated protein kinase) phospho-serine/threonine/tyrosine-binding protein] is a pseudophosphatase member of the dual-specificity phosphatase subfamily of the PTPs (protein tyrosine phosphatases). MK-STYX is catalytically inactive due to the absence of two amino acids from the signature motif that are essential for phosphatase activity. The nucleophilic cysteine residue and the adjacent histidine residue, which are conserved in all active dual-specificity phosphatases, are replaced by serine and phenylalanine residues respectively in MK-STYX. Mutations to introduce histidine and cysteine residues into the active site of MK-STYX generated an active phosphatase. Using MS, we identified G3BP1 [Ras-GAP (GTPase-activating protein) SH3 (Src homology 3) …

Thyroid Hormone Receptor Α1 Follows A Cooperative Crm1/Calreticulin-Mediated Nuclear Export Pathway, Matthew E. Grespin, Ghislain M.C. Bonamy, Vincent R. Roggero, Nicole G. Cameron, Lindsay E. Adam, Andrew P. Atchison, Lizabeth A. Allison

Arts & Sciences Articles

The thyroid hormone receptor α1 (TRα) exhibits a dual role as an activator or repressor of its target genes in response to thyroid hormone (T3). Previously, we have shown that TRα, formerly thought to reside solely in the nucleus bound to DNA, actually shuttles rapidly between the nucleus and cytoplasm. An important aspect of the shuttling activity of TRα is its ability to exit the nucleus through the nuclear pore complex. TRα export is not sensitive to treatment with the CRM1-specific inhibitor leptomycin B (LMB) in heterokaryon assays, suggesting a role for an export receptor other than CRM1. Here, we …

Oscillation Regularity In Noise-Driven Excitable Systems With Multi-Time-Scale Adaptation, William H. Nesse, Christopher A. Del Negro, Paul C. Bressloff

Arts & Sciences Articles

We investigate oscillation regularity of a noise-driven system modeled with a slow after-hyperpolarizing adaptation current (AHP) composed of multiple-exponential relaxation time scales. Sufficiently separated slow and fast AHP time scales (biphasic decay) cause a peak in oscillation irregularity for intermediate input currents I, with relatively regular oscillations for small and large currents. An analytic formulation of the system as a stochastic escape problem establishes that the phenomena is distinct from standard forms of coherence resonance. Our results explain data on the oscillation regularity of the pre-Bötzinger complex, a neural oscillator responsible for inspiratory breathing rhythm generation in mammals.

Whimbrel Tracked With Satellite Transmitter On Migratory Flight Across North America, B. D. Watts, B. R. Truitt, F. M. Smith, E. K. Mojica, Et Al.

Arts & Sciences Articles

"Two disjunct breeding populations of Whimbrel Numenius phaeopus have been described in the western hemisphere (American Ornithologists’ Union 1983). The western population breeds in portions of Alaska and across the Yukon and Northwest Territories of Canada while the eastern population breeds west and south of Hudson Bay (Skeel & Mallory 1996). Most of what we believe we know about the migratory pathways of these populations has been pieced together from circumstantial evidence gleaned from decades of field observations (Skeel & Mallory 1996, Taverner 1942). The populations have been thought to have separate migratory routes with little mixing where the western …

Activation Of The Dna-Dependent Protein Kinase Stimulates Nuclear Export Of The Androgen Receptor In Vitro, Leonard C. Shank, Joshua B. Kelly, Daniel Gioeli, Chun-Song Yang, Et Al., Lizabeth A. Allison

Arts & Sciences Articles

The androgen receptor undergoes nuclear import in response to ligand, but the mechanism by which it undergoes nuclear export is poorly understood. We developed a permeabilized cell assay to characterize nuclear export of the androgen receptor in LNCaP prostate cancer cells. We found that nuclear export of endogenous androgen receptor can be stimulated by short double-stranded DNA oligonucleotides. This androgen receptor export pathway is dependent on ATP hydrolysis and is enhanced by phosphatase inhibition with okadaic acid. Fluorescence recovery after photobleaching in permeabilized cells, under the conditions that stimulate androgen receptor export, suggested that double-stranded DNA-dependent export does not simply …

Characteristics Of Vesicomyid Clams And Their Environment At The Blake Ridge Cold Seep, South Carolina, Usa, Randolph Chambers

Arts & Sciences Articles

Spatial distributions and patchiness of dominant megafaunal invertebrates in deep-sea seep environments may indicate heterogeneities in the flux of reduced chemical compounds. At the Blake Ridge seep off South Carolina, USA, the invertebrate assemblage includes dense populations of live vesicomyid clams (an undescribed species) as well as extensive clam shell beds (i.e. dead clams). In the present study, we characterized clam parameters (density, size-frequency distribution, reproductive condition) in relation to sulfur chemistry (sulfide and sulfate concentrations and isotopic compositions, pyrite and elemental sulfur concentrations) and other sedimentary metrics (grain size, organic content). For clams >5 mm, clam density was highest …

Documentation Of Infanticide And Cannibalism In Bald Eagles, A. C. Markham, B. D. Watts

Arts & Sciences Articles

"Non-kin infanticide, the killing of dependent young by unrelated conspecifics, occurs in a wide array of taxonomic groups including mammals, insects, fish, and birds (Hrdy 1979, Hrdy and Hausfater 1984). Several hypotheses have been proposed to explain this behavior including the removal of potential competitors to gain access to limited resources such as nesting territories and food (Hrdy 1979)..."

Oncogenic Conversion Of The Thyroid Hormone Receptor By Altered Nuclear Transport, Ghislain M.C. Bonamy, Lizabeth A. Allison

Arts & Sciences Articles

Nuclear receptors (NRs) are transcription factors whose activity is modulated by ligand binding. These receptors are at the core of complex signaling pathways and act as integrators of many cellular signals. In the last decade our understanding of NRs has greatly evolved. In particular, regulation of NR subcellular dynamics has emerged as central to their activity. Research on the subcellular distribution of the thyroid hormone receptor (TR) has revealed new dimensions in the complexity of NR regulation, and points to the possibility that NR mislocalization plays a key role in oncogenesis. For many years, TR was thought to reside exclusively …

Kinosternon Subrubrum Subrubrum (Eastern Mud Turtle) Predator Escape, Joseph C. Mitchell, A. C. Markham, B. D. Watts

Arts & Sciences Articles

"Known avian predators of Kinosternon subrubrum include crows and eagles (Ernst et al. 1994. Turtles of the United States and Canada, Smithsonian Inst. Press, Washington, DC; Mitchell 1994. The Reptiles of Virginia, Smithsonian Inst. Press, Washington, DC)..."

Homing Behavior Of Musk Turtles In A Virginia Lake, Randolph Chambers

Arts & Sciences Articles

For nine weeks during the summer of 2002, a mark and recapture technique was used to study homing behavior of Musk Turtles (Sternotherus odoratus) living in Lake Matoaka, VA. During the first three weeks of the study, 119 turtles (83 male, 36 female) were captured using unbaited crabpots, then marked and displaced from the site of capture. Turtles were displaced 100 m across open water 4 m deep, 520 m along the same shore, or 550 m across open water. For the last six weeks of the study, 110 turtles (65 males, 45 females) were captured and released with no …

Cancer Promoted By The Oncoprotein V-Erba May Be Due To Subcellular Mislocalization Of Nuclear Receptors, Ghislain M.C. Bonamy, Anne Guiochon-Mantel, Lizabeth A. Allison

Arts & Sciences Articles

The retroviral v-ErbA oncoprotein is a highly mutated variant of the thyroid hormone receptor α (TRα), which is unable to bind T₃ and interferes with the action of TRα in mammalian and avian cancer cells. v-ErbA dominant-negative activity is attributed to competition with TRα for T₃-responsive DNA elements and/or auxiliary factors involved in the transcriptional regulation of T₃-responsive genes. However, competition models do not address the altered subcellular localization of v-ErbA and its possible implications in oncogenesis. Here, we report that v-ErbA dimerizes with TRα and the retinoid X receptor and sequesters a significant fraction …

Nuclear Export Of The Oncoprotein V-Erba Is Mediated By Acquisition Of A Viral Nuclear Export Sequence, Laura J. Delong, Ghislain M.C. Bonamy, Erin N. Fink, Lizabeth A. Allison

Arts & Sciences Articles

v-ErbA, an oncogenic derivative of the thyroid hormone receptor α (TRα) carried by the avian erythroblastosis virus, contains several alterations including fusion of a portion of avian erythroblastosis virus Gag to its N terminus, N- and C-terminal deletions, and 13 amino acid substitutions. Nuclear export of v-ErbA occurs through a CRM1-mediated pathway. In contrast, nuclear export of TRα and another isoform, TRβ, is CRM1-independent. To determine which amino acid changes in v-ErbA confer CRM1-dependent nuclear export, we expressed a panel of green and yellow fluorescent protein-tagged mutant and chimeric proteins in mammalian cells. The sensitivity of subcellular trafficking of these …

Recognizing Chromosomes In Trouble: Association Of The Spindle Checkpoint Protein Bub3p With Altered Kinetochores And A Unique Defective Centromere, Oliver Kerscher, Luciana B. Crotti, Munira A. Basrai

Arts & Sciences Articles

Spindle checkpoint proteins monitor the interaction of the spindle apparatus with the kinetochores, halting anaphase even if the microtubule attachment of only a single chromosome is altered. In this study, we show that Bub3p of Saccharomyces cerevisiae, an evolutionarily conserved spindle checkpoint protein, exhibits distinct interactions with an altered or defective kinetochore(s). We show for the first time that green fluorescent protein-tagged S. cerevisiae Bub3p (Bub3-GFP) exhibits not only a diffuse nuclear localization pattern but also forms distinct nuclear foci in unperturbed growing and G₂/M-arrested cells. As Bub3-GFP foci overlap only a subset of kinetochores, we tested …

Hydrologic And Chemical Control Of Phragmites Growth In Tidal Marshes Of Sw Connecticut, Usa, Randolph Chambers

Arts & Sciences Articles

We compared hydrology and porewater chemistry along transects in 3 tidal marshes vegetated by Spartina alterniflora and by the invasive species Phragmites australis. Relative to the Phragmites zone, the S. alterniflora zone occurred at lower tidal elevations in all 3 marshes and was characterized by greater depth of flooding and shorter periods of water-table drawdown below the soil surface. Penetration by Phragmites into the S. alterniflora zone appeared to be limited by extensive soil saturation at the leading edge of Phragmites growth. This mixed-species zone occurred at the intersection of the low-tide groundwater table with the soil surface and …

Breeding Bird Communities In Pine Plantations On The Coastal Plain Of North Carolina, Michael D. Wilson, B. D. Watts

Arts & Sciences Articles

"Prior to European settlement of North America, the landscape of the Southeastern United States was dominated by an estimate 55 million hectares of old growth forests (Ware et al. 1993). Since that time, three centuries of land clearing for agriculture and other uses has reduced the extent of forest cover to 60% of its former range..."

Breeding Bird Communities Of A Managed Forest Landscape In Coastal North Carolina: 1999 Report, M. D. Wilson, B. D. Watts

CCB Technical Reports

Recent concern for the status of North American bird populations has resulted in an escalation of monitoring and management efforts. Much of this effort has been focused on declining forest-dwelling species that migrate between breeding areas in North America and wintering areas in Latin America and the Caribbean. Fragmentation of temperate forests has been shown to negatively affect many of these species by exposing them to higher rates of predation and brood parasitism, resulting in lower productivity and survivorship. Weyerhaeuser Company is the largest private landowner in North Carolina. Because of the extent and geographic location of current landholdings, Weyerhaeuser's …

Breeding Bird Communities Of A Managed Forest Landscape In Coastal North Carolina: 1998 Report, M. D. Wilson, B. D. Watts

CCB Technical Reports

No abstract provided.

Stratigraphic Consistency And The Shape Of Things, Mark E. Siddall

VIMS Articles

No abstract provided.

The Use Of Night-Vision Equipment To Observe Wildlife In Forested Wetlands, Kirk J. Havens, Walter I. Priest Iii, Ann Jennings

VIMS Articles

Urban forested wetlands and rural forested wetlands were studied to investigate the effectiveness of night-vision image intensifier equipment in the observation of medium-to-large animals and to investigate if surrounding landscape type influences wetland habitat value. Bats, cats, dogs, owls, deer, and humans were easily observed using the night-vision equipment. Differences in species use between the rural and urban forested wetland were observed. Light levels and noise levels were significantly higher (p

Spatio-Temporal Patterns Of Landbird Migration On The Lower Delmarva Peninsula (Interim), B. D. Watts, S. E. Mabey

CCB Technical Reports

No abstract provided.

Bahamas Bibliography : A List Of Citations For Scientific, Engineering And Historical Articles Pertaining To The Bahama Islands, Carol Fang, W. Harrison

Reports

Specialized bibliographies are sometimes needed in connection with the research studies being pursued at the Virginia Institute of Marine Science. The Bahamas Bibliography arose out of the needs of marine geologists, biologists and physical oceanographers engaged in studies of beaches, fishes and inlet currents in the Bahama Islands. Although the present bibliography may suffer from completeness, it significantly surpasses in number of citations the only other known bibliography of like kind.