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Full-Text Articles in Life Sciences
Use Of Esi-Fticr-Ms To Characterize Dissolved Organic Matter In Headwater Streams Draining Forest-Dominated And Pasture-Dominated Watersheds, Randolph Chambers
Use Of Esi-Fticr-Ms To Characterize Dissolved Organic Matter In Headwater Streams Draining Forest-Dominated And Pasture-Dominated Watersheds, Randolph Chambers
Arts & Sciences Articles
Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) has proven to be a powerful technique revealing complexity and diversity of natural DOM molecules, but its application to DOM analysis in grazing-impacted agricultural systems remains scarce. In the present study, we presented a case study of using ESI-FTICR-MS in analyzing DOM from four headwater streams draining forest- or pasture-dominated watersheds in Virginia, USA. In all samples, most formulas were CHO compounds (71.8–87.9%), with other molecular series (CHOS, CHON, CHONS, and CHOP (N, S)) accounting for only minor fractions. All samples were dominated by molecules falling in the lignin-like region …
Dbx1 Precursor Cells Are A Source Of Inspiratory Xii Premotoneurons., Ann L. Revill, Nicolas C. Vann, Victoria T. Akins, Andrew Kottick, Paul A. Gray, Christopher A. Del Negro, Gregory D. Funk
Dbx1 Precursor Cells Are A Source Of Inspiratory Xii Premotoneurons., Ann L. Revill, Nicolas C. Vann, Victoria T. Akins, Andrew Kottick, Paul A. Gray, Christopher A. Del Negro, Gregory D. Funk
Arts & Sciences Articles
All behaviors require coordinated activation of motoneurons from central command and premotor networks. The genetic identities of premotoneurons providing behaviorally relevant excitation to any pool of respiratory motoneurons remain unknown. Recently, we established in vitro that Dbx1-derived pre-Bo¨ tzinger complex neurons are critical for rhythm generation and that a subpopulation serves a premotor function (Wang et al., 2014). Here, we further show that a subpopulation of Dbx1-derived intermediate reticular (IRt) neurons are rhythmically active during inspiration and project to the hypoglossal (XII) nucleus that contains motoneurons important for maintaining airway patency. Laser ablation of Dbx1 IRt neurons, 57% of which …
Landfill Use By Bald Eagles In The Chesapeake Bay Region, Courtney Turrin, B. D. Watts, Elizabeth K. Mojica
Landfill Use By Bald Eagles In The Chesapeake Bay Region, Courtney Turrin, B. D. Watts, Elizabeth K. Mojica
Arts & Sciences Articles
We examined patterns in the use of landfills (rubbish dumps) in the Chesapeake Bay by Bald Eagles (Haliaeetus leucocephalus). Sites of solid waste landfills (n = 72) were located using state databases. Satellite tracking data from 64 eagles were used to track eagle movements hourly during daylight and once at midnight to determine roosting locations (2007–2012). Landfill use varied significantly with age class, with hatch-year birds using landfills six times more often than adults and twice as often as third- and fourth-year birds. Hatch-year birds spent significantly more time at landfills than expected based on landfill area …
Seasonal Variation In Space Use By Nonbreeding Bald Eagles Within The Upper Chesapeake Bay, B. D. Watts, Elizabeth K. Mojica, B. J. Paxton
Seasonal Variation In Space Use By Nonbreeding Bald Eagles Within The Upper Chesapeake Bay, B. D. Watts, Elizabeth K. Mojica, B. J. Paxton
Arts & Sciences Articles
Access to food resources is essential to self-maintenance and reproduction and, for species of conservation concern, foraging areas are considered critical habitat. Human disturbance is an important factor restricting access to prey resources for Bald Eagles (Haliaeetus leucocephalus) and guidelines in the Chesapeake Bay have been developed to mitigate its impact. However, our ability to implement such guidelines has been limited by a lack of information on important foraging areas. We used Brownian bridge movement modeling to develop a population-wide utilization probability surface for Bald Eagles along shorelines within the upper Chesapeake Bay. We used locations (n …
Mechanisms Leading To Rhythm Cessation In The Respiratory Prebotzinger Complex Due To Piecewise Cumulative Neuronal Deletions, Hanbing Song, John A. Hayes, Nicolas A. Vann, M. Drew Lamar, Christopher A. Del Negro
Mechanisms Leading To Rhythm Cessation In The Respiratory Prebotzinger Complex Due To Piecewise Cumulative Neuronal Deletions, Hanbing Song, John A. Hayes, Nicolas A. Vann, M. Drew Lamar, Christopher A. Del Negro
Arts & Sciences Articles
The brainstem pre-Botzinger complex (preBotC) generates the rhythm underlying inspiratory breathing movements and its core interneurons are derived from Dbx-1 expressing precursors. Recurrent synaptic excitation is required to initiate inspiratory bursts, but whether excitatory synaptic mechanisms also contribute to inspiratory–expiratory phase transition is unknown. Here, we examined the role of short-term synaptic depression using a rhythmically active neonatal mouse brainstem slice preparation. We show that different axonal projections to Dbx-1 PreBotC neurons undergo activity-dependent depression and we identify a refractory period (approx. 2 s) after endogenous inspiratory bursts that precludes light-evoked bursts in channelrhodopsin-expressing Dbx1 Pre-BotC neurons. We demonstrate that …
Multiple Exportins Influence Thyroid Hormone Receptor Localization, Kelly Subramanian, Rose C. Dziedzic, Hallie N. Nelson, Mary E. Stern, Vincent R. Roggero, Cornelius Bondzi, Lizabeth A. Allison
Multiple Exportins Influence Thyroid Hormone Receptor Localization, Kelly Subramanian, Rose C. Dziedzic, Hallie N. Nelson, Mary E. Stern, Vincent R. Roggero, Cornelius Bondzi, Lizabeth A. Allison
Arts & Sciences Articles
The thyroid hormone receptor (TR) undergoes nucleocytoplasmic shuttling and regulates target genes involved in metabolism and development. Previously, we showed that TR follows a CRM1/calreticulinmediated nuclear export pathway. However, two lines of evidence suggest TR also follows another pathway: export is only partially blocked by leptomycin B (LMB), a CRM1-specific inhibitor; and we identified nuclear export signals in TR that are LMB-resistant. To determine whether other exportins are involved in TR shuttling, we used RNA interference and fluorescence recovery after photobleaching shuttling assays in transfected cells. Knockdown of exportins 4, 5, and 7 altered TR shuttling dynamics, and when exportins …
Mucous Contribution To Gut Nutrient Content In American Gizzard Shad Dorosoma Cepedianum, L. L. Holley, M K. Heidman, Randolph Chambers, S. Laurie Sanderson
Mucous Contribution To Gut Nutrient Content In American Gizzard Shad Dorosoma Cepedianum, L. L. Holley, M K. Heidman, Randolph Chambers, S. Laurie Sanderson
Arts & Sciences Articles
This study developed and applied an approach to calculate the proportion of fish gut content composed of mucus secreted by the oropharyngeal cavity and gut. The amount of nitrogen in the contents of the foregut (oesophagus and gizzard) and the epibranchial organs of suspension‐feeding American gizzard shad Dorosoma cepedianum was significantly higher than the nitrogen in the homogeneous food source. Using data collected from suspension‐feeding experiments and the nitrogen content of D. cepedianum mucus, a series of equations illustrated that mucus constituted c. 10% of D. cepedianum foregut content and 12% of epibranchial organ content by dry mass. Future quantification …
Nest Guarding In Chesapeake Bay Bald Eagles, Courtney Turrin, B. D. Watts
Nest Guarding In Chesapeake Bay Bald Eagles, Courtney Turrin, B. D. Watts
Arts & Sciences Articles
As Bald Eagle (Haliaeetus leucocephalus) populations approach carrying capacity in the Chesapeake Bay, competition for breeding territories appears to be intensifying. Frequent territorial interactions may force breeders to adjust nest-guarding behavior. We examined nest-guarding behaviors at active Bald Eagle nests in the lower Chesapeake Bay during the nesting season (2012 and 2013). Guarding coverage was 13.7 ± 4.2% of total observation time during the pre-laying period, 6.8 ± 2.2% of observation time in the incubation period, and 26.3 ± 3.2% of observation time in the nestling period. Females were present in the nest area for 80.0 ± 2.7% …