466 research outputs found
Autumn Foods of White-Tailed Deer in Arkansas
Rumen contents from 65 hunter-harvested deer were collected and analyzed during 1985-86 to estimate the principal autumn foods consumed by white-tailed deer inhabiting the Ozark Mountains, Arkansas River Valley, and Gulf Coastal Plain regions of Arkansas. Deer in the Ozarks and Coastal Plain fed heavily on woody browse species, which comprised 99% of rumina identified from these 2 regions. Acorns were the primary food of deer in these heavily forested areas. Acorns and other woody browse were less important to deer inhabiting the Arkansas River Valley. In this region of interspersed agricultural fields and bottomland forests, soybeans and corn comprised 75% of the diet, and acorns accounted for only 2%
Site-Specific Incorporation of Selenocysteine by Genetic Encoding as a Photocaged Unnatural Amino Acid
Selenocysteine (Sec) is a naturally occurring amino acid that is also referred to as the 21st amino acid. Site-specific incorporation of Sec into proteins is attractive, because the reactivity of a selenol group exceeds that of a thiol group and thus allows site-specific protein modifications. It is incorporated into proteins by an unusual enzymatic mechanism which, in E. coli and other organisms, involves the recognition of a selenocysteine insertion sequence (SECIS) in the mRNA of the target protein. Reengineering of the natural machinery for Sec incorporation at arbitrary sites independent of SECIS elements, however, is challenging. Here we demonstrate an alternative route, whereby a photocaged selenocysteine (PSc) is incorporated as an unnatural amino acid in response to an amber stop codon, using a mutant Methanosarcina mazei pyrrolysyl-tRNA synthetase, Mm PCC2RS, and its cognate tRNACUA. Following decaging by UV irradiation, proteins synthesized with PSc are readily tagged, e.g., with NMR probes to study ligand binding by NMR spectroscopy. The approach provides a facile route for genetically encoded Sec incorporation. It allows the production of pure selenoproteins and the Sec residue enables site-specific covalent protein modification with reagents that would usually react first with naturally occurring cysteine residues. The much greater reactivity of Sec residues allows their selective alkylation in the presence of highly solvent-exposed cysteine residues.Financial support by the Australian Research Council,
including a Laureate Fellowship to G.O., is gratefully acknowledged
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Mouse cytomegalovirus-experienced ILC1s acquire a memory response dependent on the viral glycoprotein m12.
Innate lymphoid cells (ILCs) are tissue-resident sentinels that are essential for early host protection from pathogens at initial sites of infection. However, whether pathogen-derived antigens directly modulate the responses of tissue-resident ILCs has remained unclear. In the present study, it was found that liver-resident type 1 ILCs (ILC1s) expanded locally and persisted after the resolution of infection with mouse cytomegalovirus (MCMV). ILC1s acquired stable transcriptional, epigenetic and phenotypic changes a month after the resolution of MCMV infection, and showed an enhanced protective effector response to secondary challenge with MCMV consistent with a memory lymphocyte response. Memory ILC1 responses were dependent on the MCMV-encoded glycoprotein m12, and were independent of bystander activation by proinflammatory cytokines after heterologous infection. Thus, liver ILC1s acquire adaptive features in an MCMV-specific manner
Trimethylsilyl tag for probing protein-ligand interactions by NMR
Protein-ligand titrations can readily be monitored with a trimethylsilyl (TMS) tag. Owing to the intensity, narrow line shape and unique chemical shift of a TMS group, dissociation constants can be determined from straightforward 1D 1H-NMR spectra not only in the fast but also in the slow exchange limit. The tag is easily attached to cysteine residues and a sensitive reporter of ligand binding also at sites where it does not interfere with ligand binding or catalytic efficiency of the target protein. Its utility is demonstrated for the Zika virus NS2B-NS3 protease and the human prolyl isomerase FK506 binding protein.C.N. and G.O. thank the Alexander von Humboldt Foundation for a
Feodor Lynen Fellowship and the Australian Research Council for a
Laureate Fellowship, respectively. Financial project support by the
Australian Research Council, the Austrian Science Fund (FWF) (DK
Molecular Enzymology W901 to K.Z.) and by NAWI Graz is gratefully
acknowledged
Pulse EPR-enabled interpretation of scarce pseudocontact shifts induced by lanthanide binding tags
Pseudocontact shifts (PCS) induced by tags loaded with paramagnetic lanthanide ions provide powerful long-range structure information, provided the location of the metal ion relative to the target protein is known. Usually, the metal position is determined by fitting the magnetic susceptibility anisotropy (Δχ) tensor to the 3D structure of the protein in an 8-parameter fit, which requires a large set of PCSs to be reliable. In an alternative approach, we used multiple Gd(3+)-Gd(3+) distances measured by double electron-electron resonance (DEER) experiments to define the metal position, allowing Δχ-tensor determinations from more robust 5-parameter fits that can be performed with a relatively sparse set of PCSs. Using this approach with the 32 kDa E. coli aspartate/glutamate binding protein (DEBP), we demonstrate a structural transition between substrate-bound and substrate-free DEBP, supported by PCSs generated by C3-Tm(3+) and C3-Tb(3+) tags attached to a genetically encoded p-azidophenylalanine residue. The significance of small PCSs was magnified by considering the difference between the chemical shifts measured with Tb(3+) and Tm(3+) rather than involving a diamagnetic reference. The integrative sparse data approach developed in this work makes poorly soluble proteins of limited stability amenable to structural studies in solution, without having to rely on cysteine mutations for tag attachment.Financial support by the Australian Research Council (ARC) and an Australia-Weizmann Making Connections grant is gratefully acknowledged. B. G. thanks the ARC for a Future Fellowship
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Breaking convention: a seismic shift in psychedelia
The latest collection of essays from the cutting edge of psychedelic research, based on talks given by their authors at Breaking Convention 2019, held at The University of Greenwich, London. The largest symposium of its kind, Breaking Convention features more than 120 academic presentations biennially, and is widely regarded as the foremost global platform for serious research into psychedelic science and culture. Within these pages are essays demonstrating a shift in psychedelia. Topics include sustainability, death, the shadow, archetypes, conservation, history, phenomenology, war, power, madness, and the marriage of energy and matter. An eclectic collection that reflects the diverse array of speakers that present at Breaking Convention, and echoes the shifts currently occurring in psychedelia: a build up of tension before new ground is created
Faint extended Lyalpha emission due to star formation at the centre of high-column density QSO absorption systems
We use detailed Lyalpha radiative transfer calculations to further test the
claim of Rauch et al. (2008) that they have detected spatially extended faint
Lyalpha emission from the elusive host population of Damped Lyalpha Absorption
systems (DLAs) in their recent ultra-deep spectroscopic survey. We investigate
the spatial and spectral distribution of Lyalpha emission due to star-formation
at the centre of DLAs, and its dependence on the spatial and velocity structure
of the gas. Our model simultaneously reproduces the observed properties of DLAs
and the faint Lyalpha emitters, including the velocity width and column density
distribution of DLAs and the large spatial extent of the emission of the faint
emitters. Our modelling confirms previous suggestions that DLAs are
predominately hosted by Dark Matter (DM) halos in the mass range
10^{9.5}-10^{12} M_sun, and are thus of significantly lower mass than those
inferred for L_* Lyman Break Galaxies (LBGs). Our modelling suggests that DM
halos hosting DLAs retain up to 20% of the cosmic baryon fraction in the form
of neutral hydrogen, and that star formation at the centre of the halos is
responsible for the faint Lyalpha emission. The scattering of a significant
fraction of the Lyalpha emission to the observed radii, which can be as large
as 50 kpc or more, requires the amplitude of the bulk motions of the gas at the
centre of the halos to be moderate. The observed space density and size
distribution of the emitters together with the incidence rate of DLAs suggests
that the Lyalpha emission due to star formation has a duty cycle of ~ 25%.Comment: 17 pages, 13 figures, Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Meditation smartphone application effects on prehypertensive adults' blood pressure: Dose-response feasibility trial
OBJECTIVE:
Essential hypertension (EH) is the most common chronic disease in the United States and a major cause of morbidity and mortality. Lifestyle interventions (e.g., diet, exercise, stress management) to reduce blood pressure (BP) are often complex with varying effectiveness. Breathing awareness meditation (BAM) is a stress management strategy with encouraging effects on BP, though widespread dissemination is hampered by the lack of an easy-to-use methodology to train and monitor BAM practices. A smartphone application (Tension Tamer [TT]) that implements BAM and tracks adherence has shown promise in addressing these gaps. This 6-month dose-response feasibility trial evaluated effects of the app on BP to further optimize BAM user guidelines.
METHODS:
Sixty-four adults with prehypertension were randomized to complete TT-guided BAM sessions for 5-, 10-, or 15-min intervals twice daily over 6 months. Continuous heart rate readings derived from the phone's video camera via reflective photoplethysmography were used as feedback and as an index of time-stamped adherence. Outcomes (resting BP, HR) were collected at baseline, 1-, 3-, and 6-months.
RESULTS:
Mixed modeling results showed a significant time effect for systolic BP (SBP) with a dose-response effect at Months 3 and 6. Adherence declined over time and was lowest in the 15-min dose condition, though SBP reductions were maintained. Generally, adherence was negatively associated with dose as the study progressed.
CONCLUSIONS:
Smartphone-implemented BAM appears to reduce SBP and can be a low-cost method to reach large populations. (PsycINFO Database Recor
Topology and Ground State Control In Open-Shell Donor-Acceptor Conjugated Polymers
Donor-acceptor (DA) conjugated polymers (CPs) with narrow bandgaps and open-shell (diradical) character represent an emerging class of materials whose rich behavior emanates from their collective electronic properties and diminished electron pairing. However, the structural and electronic heterogeneities that define these materials complicate bandgap control at low energies and connections linking topology, exchange interactions, and (opto)electronic functionality remain nascent. To address these challenges, we demonstrate structurally rigid and strongly π-conjugated copolymers comprised of a solubilizing thiadiazoloquinoxaline acceptor and cyclopenta[2,1-b:3,4-b′]dithiophene or dithieno[3,2-b:2′,3′-d]thiophene donors. Atom-specific substitution modulates local aromatic character within the donor resulting in dramatic differences in structural, physicochemical, electronic, and magnetic properties of the polymers. These long-range π-mediated interactions facilitate control between low-spin aromatic and high-spin quinoidal forms. This work provides a strategy to understand the evolution of the electronic structure within DA CPs, control the ground state spin multiplicity, tune spin-spin interactions, and articulate the emergence of their novel properties
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