2,569 research outputs found
Record of an alleged Solitary Eagle in Oaxaca is a Great Black Hawk
In a recent article in this journal (GarcĂa-Grajales et al., 2018), an adult Great Black Hawk (Buteogallus urubitinga) was mistakenly identified as an adult of the Solitary Eagle (Buteogallus solitarius). The Solitary Eagle differs from the Greater Black Eagle in having the longest and widest wings, and the shortest tail. These characteristics give it a more triangular shape in flight. These differences are easy to see in Figures 1â3. The same authors also cite a case of the nesting of the Solitary Eagle in Mexico (Smith, 1982). However, after reviewing photos of the young, we consider that this record is probably the Common Black Hawk (B. anthracinus). The illustrations of the Solitary Eagle in field guides of Mexico and Central America (Howell & Webb, 1995; Van Perlo, 2006) demonstrate greater similarity with the Great Black Hawk, contributing to the frequent confusion of the two species if used without consulting the text. The new features published here and in Clark et al. (2006) and Clark and Schmitt (2017) should help with correct identification of Buteogallus species in the future.En un artĂculo reciente en esta revista (GarcĂa-Grajales et al., 2018), un adulto del Aguililla Negra Mayor (Buteogallus urubitinga) fue identificado errĂłneamente como un adulto del Ăguila Solitaria (Buteogallus solitarius). El Ăguila Solitaria difiere del Aguililla Negra Mayor en tener las alas mĂĄs largas y anchas, y la cola mĂĄs corta. Estas caracterĂsticas le confieren una forma mĂĄs triangular en el vuelo. Estas diferencias son fĂĄciles de apreciar en la Figuras 1â3. Los mismos autores tambiĂ©n citan un caso del anidamiento del Ăguila Solitaria en MĂ©xico (Smith, 1982). Sin embargo, despuĂ©s de revisar fotos de las crĂas, consideramos que este registro probablemente se trata del Aguililla Negra Menor (B. anthracinus). Las ilustraciones del Ăguila Solitaria en guĂas de campo de MĂ©xico y CentroamĂ©rica (Howell & Webb, 1995; Van Perlo, 2006) demuestran mayor similitud con el Aguililla Negra Mayor, contribuyendo a la confusiĂłn frecuente de las dos especies si se utilizan sin consultar el texto. Las nuevas caracterĂsticas publicadas aquĂ y en Clark et al. (2006) y Clark y Schmitt (2017) deben ayudar a su correcta identificaciĂłn en el futuro
Quantification of Hair Cortisol Concentration in Common Marmosets (\u3cem\u3eCallithrix jacchus\u3c/em\u3e) and Tufted Capuchins (\u3cem\u3eCebus apella\u3c/em\u3e)
Quantifying cortisol concentration in hair is a non-invasive biomarker of long-term hypothalamic-pituitary-adrenal (HPA) activation, and thus can provide important information on laboratory animal health. Marmosets (Callithrix jacchus) and capuchins (Cebus apella) are New World primates increasingly used in biomedical and neuroscience research, yet published hair cortisol concentrations for these species are limited. Review of the existing published hair cortisol values from marmosets reveals highly discrepant values and the use of variable techniques for hair collection, processing, and cortisol extraction. In this investigation we utilized a well-established, standardized protocol to extract and quantify cortisol from marmoset (n = 12) and capuchin (n = 4) hair. Shaved hair samples were collected from the upper thigh during scheduled exams and analyzed via methanol extraction and enzyme immunoassay. In marmosets, hair cortisol concentration ranged from 2710 â 6267 pg/mg and averaged 4070 ± 304 pg/mg. In capuchins, hair cortisol concentration ranged from 621 â 2089 pg/mg and averaged 1092 ± 338 pg/mg. Hair cortisol concentration was significantly different between marmosets and capuchins, with marmosets having higher concentrations than capuchins. The incorporation of hair cortisol analysis into research protocols provides a non-invasive measure of HPA axis activity over time, which offers insight into animal health. Utilization of standard protocols across laboratories is essential to obtaining valid measurements and allowing for valuable future cross-species comparisons
OleD Loki as a Catalyst for Tertiary Amine and Hydroxamate Glycosylation
We describe the ability of an engineered glycosyltransferase (OleD Loki) to catalyze the Nâglycosylation of tertiaryâamineâcontaining drugs and trichostatin hydroxamate glycosyl ester formation. As such, this study highlights the first bacterial model catalyst for tertiaryâamine Nâglycosylation and further expands the substrate scope and synthetic potential of engineered OleDs. In addition, this work could open the door to the discovery of similar capabilities among other permissive bacterial glycosyltransferases
A single center phase II study of ixazomib in patients with relapsed or refractory cutaneous or peripheral Tâcell lymphomas
The transcription factor GATAâ3, highly expressed in many cutaneous Tâcell lymphoma (CTCL) and peripheral Tâcell lymphomas (PTCL), confers resistance to chemotherapy in a cellâautonomous manner. As GATAâ3 is transcriptionally regulated by NFâÎșB, we sought to determine the extent to which proteasomal inhibition impairs NFâÎșB activation and GATAâ3 expression and cell viability in malignant T cells. Proteasome inhibition, NFâÎșB activity, GATAâ3 expression, and cell viability were examined in patientâderived cell lines and primary Tâcell lymphoma specimens ex vivo treated with the oral proteasome inhibitor ixazomib. Significant reductions in cell viability, NFâÎșB activation, and GATAâ3 expression were observed preclinically in ixazomibâtreated cells. Therefore, an investigatorâinitiated, singleâcenter, phase II study with this agent in patients with relapsed/refractory CTCL/PTCL was conducted. Concordant with our preclinical observations, a significant reduction in NFâÎșB activation and GATAâ3 expression was observed in an exceptional responder following one month of treatment with ixazomib. While ixazomib had limited activity in this small and heterogeneous cohort of patients, inhibition of the NFâÎșB/GATAâ3 axis in a single exceptional responder suggests that ixazomib may have utility in appropriately selected patients or in combination with other agents.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139920/1/ajh24895.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139920/2/ajh24895_am.pd
Swimming Against the Flow: Environmental DNA Can Detect Bull Sharks (\u3ci\u3eCarcharhinus leucas\u3c/i\u3e) Across a Dynamic Deltaic Interface
© 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd Human activities in coastal areas are accelerating ecosystem changes at an unprecedented pace, resulting in habitat loss, hydrological modifications, and predatory species declines. Understanding how these changes potentially cascade across marine and freshwater ecosystems requires knowing how mobile euryhaline species link these seemingly disparate systems. As upper trophic level predators, bull sharks (Carcharhinus leucas) play a crucial role in marine and freshwater ecosystem health. Telemetry studies in Mobile Bay, Alabama, suggest that bull sharks extensively use the northern portions of the bay, an estuarineâfreshwater interface known as the Mobile-Tensaw Delta. To assess whether bull sharks use freshwater habitats in this region, environmental DNA surveys were conducted during the dry summer and wet winter seasons in 2018. In each season, 5 Ă 1 L water samples were collected at each of 21 sites: five sites in Mobile Bay, six sites in the Mobile-Tensaw Delta, and ten sites throughout the Mobile-Tombigbee and Tensaw-Alabama Rivers. Water samples were vacuum-filtered, DNA extractions were performed on the particulate, and DNA extracts were analyzed with Droplet Digitalâą Polymerase Chain Reaction using species-specific primers and an internal probe to amplify a 237-base pair fragment of the mitochondrial NADH dehydrogenase subunit 2 gene in bull sharks. One water sample collected during the summer in the Alabama River met the criteria for a positive detection, thereby confirming the presence of bull shark DNA. While preliminary, this finding suggests that bull sharks use less-urbanized, riverine habitats up to 120 km upriver during Alabama\u27s dry summer season
Entropic Tension in Crowded Membranes
Unlike their model membrane counterparts, biological membranes are richly
decorated with a heterogeneous assembly of membrane proteins. These proteins
are so tightly packed that their excluded area interactions can alter the free
energy landscape controlling the conformational transitions suffered by such
proteins. For membrane channels, this effect can alter the critical membrane
tension at which they undergo a transition from a closed to an open state, and
therefore influence protein function \emph{in vivo}. Despite their obvious
importance, crowding phenomena in membranes are much less well studied than in
the cytoplasm.
Using statistical mechanics results for hard disk liquids, we show that
crowding induces an entropic tension in the membrane, which influences
transitions that alter the projected area and circumference of a membrane
protein. As a specific case study in this effect, we consider the impact of
crowding on the gating properties of bacterial mechanosensitive membrane
channels, which are thought to confer osmoprotection when these cells are
subjected to osmotic shock. We find that crowding can alter the gating energies
by more than in physiological conditions, a substantial fraction of
the total gating energies in some cases.
Given the ubiquity of membrane crowding, the nonspecific nature of excluded
volume interactions, and the fact that the function of many membrane proteins
involve significant conformational changes, this specific case study highlights
a general aspect in the function of membrane proteins.Comment: 20 pages (inclduing supporting information), 4 figures, to appear in
PLoS Comp. Bio
Low-Temperature Specific Heat of an Extreme-Type-II Superconductor at High Magnetic Fields
We present a detailed study of the quasiparticle contribution to the
low-temperature specific heat of an extreme type-II superconductor at high
magnetic fields. Within a T-matrix approximation for the self-energies in the
mixed state of a homogeneous superconductor, the electronic specific heat is a
linear function of temperature with a linear- coefficient
being a nonlinear function of magnetic field . In the range of magnetic
fields H\agt (0.15-0.2)H_{c2} where our theory is applicable, the calculated
closely resembles the experimental data for the borocarbide
superconductor YNiBC.Comment: 7 pages, 2 figures, to appear in Physical Review
Extensive HST Ultraviolet Spectra and Multi-wavelength Observations of SN 2014J in M82 Indicate Reddening and Circumstellar Scattering by Typical Dust
SN 2014J in M82 is the closest detected Type Ia supernova (SN Ia) in at least
28 years and perhaps in 410 years. Despite its small distance of 3.3 Mpc, SN
2014J is surprisingly faint, peaking at V = 10.6 mag, and assuming a typical SN
Ia luminosity, we infer an observed visual extinction of A_V = 2.0 +/- 0.1 mag.
But this picture, with R_V = 1.6 +/- 0.2, is too simple to account for all
observations. We combine 10 epochs (spanning a month) of HST/STIS ultraviolet
through near-infrared spectroscopy with HST/WFC3, KAIT, and FanCam photometry
from the optical to the infrared and 9 epochs of high-resolution TRES
spectroscopy to investigate the sources of extinction and reddening for SN
2014J. We argue that the wide range of observed properties for SN 2014J is
caused by a combination of dust reddening, likely originating in the
interstellar medium of M82, and scattering off circumstellar material. For this
model, roughly half of the extinction is caused by reddening from typical dust
(E(B-V ) = 0.45 mag and R_V = 2.6) and roughly half by scattering off LMC-like
dust in the circumstellar environment of SN 2014J.Comment: 17 pages (excluding references and tables), 15 figures, accepted to
MNRAS. A high-resolution HST image of SN 2014J in M82 is available upon
reques
Age and growth of longfinned eels (Anguilla dieffenbachii) in pastoral and forested streams in the Waikato River basin, and in two hydro-electric lakes in the North Island, New Zealand
Growth rates of New Zealand endemic longfinned eels (Anguilla dieffenbachii) from streams in pasture and indigenous forest, and from two hydroelectric lakes (Lakes Karapiro and Matahina), were estimated by otolith examination. Habitat-specific growth was further investigated with measurement of widths of annual bands in otoliths. Longfinned eels 170-1095 mm in length ranged between 4 and 60 years old (N=252). Eels in pastoral streams grew faster (mean annual length increment ±95% CL = 24 ± 3 mm to 36 ± 7 mm) than eels in streams in indigenous forest (annual length increment 12 ± 2 mm to 15 ± 3 mm). Eels from the hydro-electric lakes had growth rates (annual length increments 19 ± 4 and 19 + 7 mm) similar to eels from pastoral streams. Otoliths of most eels showed annual band widths that indicated growth in several different habitats, corresponding to growth during upstream migration, and limited movement among adult habitats. Estimated age at marketable size (220 g) ranged between 7 and 26 years. The particularly slow growth of longfinned eels in streams in indigenous forest has considerable implications for management. The fast growth rates of eels in hydro-electric lakes provides evidence for the potential of increased eel production by stocking. The probable selective production of female eels in these lakes may be nationally important to allow enhancement of breeding stocks
Measurement of Protein Tyrosine Phosphatase Activity in Single Cells by Capillary Electrophoresis
A fluorescent peptide substrate was used to measure dephosphorylation by protein tyrosine phosphatases (PTP) in cell lysates, and single cells and to investigate the effect of environmental toxins on PTP activity in these systems. Dephosphorylation of the substrate by PTPN1 and PTPN2 obeyed Michaelis-Menten kinetics, with KM values of 770 ± 250 nM and 290 ± 54 nM, respectively. Dose-response curves and IC50 values were determined for the inhibition of these two enzymes by the environmental toxins Zn2+ and 1,2-naphthoquinone, as well as pervanadate. In A431 cell lysates, the reporter was a poor substrate for peptidases (degradation rate of 100 ± 8.2 fmol minâ1 mgâ1) but an excellent substrate for phosphatases (dephosphorylation rate of 1.4 ± 0.3 nmol minâ1 mgâ1). Zn2+, 1,2-naphthoquinone and pervanadate inhibited dephosphorylation of the reporter in cell lysates with IC50 values of 470 nM, 35 ÎŒM, and 100 nM, respectively. Dephosphorylation of the reporter following loading into living single cells occurred at rates of at least 2 pmol minâ1 mgâ1. When single cells were exposed to 1,2-naphthoquinone (50 ÎŒM), Zn2+ (100 ÎŒM), and pervandate (1 mM), dephosphorylation was inhibited with median values and first and third quartile values of 41 (Q1 = 0%, Q3 = 96%), 50 (Q1 = 46%, Q3 = 74%), and 53% (Q1 = 36%, Q3 = 77%), respectively, demonstrating both the impact of these toxic exposures on cell signaling and the heterogeneity of response between cells. This approach will provide a valuable tool for the study of PTP dynamics, particularly in small, heterogeneous populations such as human biopsy specimens
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