A MULTI‐GENE ESTIMATE OF HIGHER‐LEVEL PHYLOGENETIC RELATIONSHIPS AMONG NIGHTJARS (AVES: CAPRIMULGIDAE)

ABSTRACT ∙ The higher‐level phylogenetic relationships of the nightjars and nighthawks (Caprimulgidae) have been challenging for traditional systematics due to their cryptic plumage and conservative morphology. We explored these relationships by combining two previously published molecular datasets with new data to generate a complete matrix (7,104 bp) of evolutionarily disparate sequence elements from four genes for 36 taxa. We analyzed each of the genes separately for base composition heterogeneity and heterozygosity. We analyzed the concatenated matrix in a likelihood framework using seven different partitioning schemes. As the number of subsets in a given partitioning scheme increased, tree length and likelihood score also increased; however, the branching topology was little affected by increasingly complex partitioning schemes. Our best maximum likelihood tree has increased bootstrap support at 13 of 30 ingroup nodes compared with previous analyses, a result likely due to doubling the length of the sequence data. Coalescent‐based species tree inference produced a tree congruent with all strongly supported nodes in the maximum likelihood tree. This topology agrees with previous molecular studies in identifying three small, early branching Old World genera (Eurostopodus, Lyncornis, and Gactornis) and four more speciose terminal clades, representing the New World nighthawks (genus Chordeiles) and three nightjar radiations centered in South America, Central America and the Old World, respectively. Increased node support across the tree reinforces a historical scenario with origins in the region surrounding the Indian Ocean, followed by diversification in the New World and subsequent recolonization and radiation in the Old World. Future work on this group should incorporate additional members of the genera Lyncornis and Eurostopodus, to determine which is the basal lineage of Caprimulgidae.RESUMEN ∙ Relaciones filogenéticas de más alto nivel de los atajacaminos (Aves: Caprimulgidae) en base a un análisis multigénico Las relaciones filogenéticas de más alto nivel de los atajacaminos y añaperos (Caprimulgidae) son un reto para la sistemática tradicional, debido a que el grupo posee morfología poco variable y plumajes crípticos. Exploramos relaciones filogenéticas en el grupo combinando dos conjuntos de datos moleculares ya publicados con nuevos datos. La matriz completa (7,104 bp) se generó con cuatro genes y 36 taxones, incluyendo marcadores con distintos modelos de evolución. Se examinó cada uno de los genes por separado para determinar heterocigosidad y heterogeneidad de la composición de bases. Se analizó la matriz concatenada en un marco de máxima verosimilitud utilizando siete particiones diferentes. La longitud de los árboles filogenéticos y su verosimilitud aumentaron a la par del número de subconjuntos en una partición particular; sin embargo, la topología del árbol varió poco entre particiones. En comparación con topologías publicadas, nuestro árbol de máxima verosimilitud tuvo mejor soporte para 13 de los 30 nodos internos, resultado que podría deberse al uso del doble de los datos de secuencias. El método de árboles de especies basado en coalescencia produjo una topología congruente con la obtenida por máxima verosimilitud. Esta topología concuerda con previos estudios moleculares, identificando tres pequeños géneros del Viejo Mundo como basales en la filogenia (Eurostopodus, Lyncornis y Gactornis), y cuatro clados terminales con más especies. Estos clados terminales representan los atajacaminos del Nuevo Mundo del género Chordeiles, y otras tres radiaciones de América del Sur, Central y del Viejo Mundo. Nuestros resultados sugieren un escenario histórico con orígenes del grupo en la región circundante al Océano Indico, seguido por la diversificación en las Américas y la posterior recolonización y radiación en el Viejo Mundo. Futuros estudios en este grupo deben incorporar miembros adicionales de los géneros Lyncornis y Eurostopodus, lo que permitirá estudiar cuál es el linaje basal de Caprimulgidae

MTHFD1 controls DNA methylation in Arabidopsis.

DNA methylation is an epigenetic mechanism that has important functions in transcriptional silencing and is associated with repressive histone methylation (H3K9me). To further investigate silencing mechanisms, we screened a mutagenized Arabidopsis thaliana population for expression of SDCpro-GFP, redundantly controlled by DNA methyltransferases DRM2 and CMT3. Here, we identify the hypomorphic mutant mthfd1-1, carrying a mutation (R175Q) in the cytoplasmic bifunctional methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase (MTHFD1). Decreased levels of oxidized tetrahydrofolates in mthfd1-1 and lethality of loss-of-function demonstrate the essential enzymatic role of MTHFD1 in Arabidopsis. Accumulation of homocysteine and S-adenosylhomocysteine, genome-wide DNA hypomethylation, loss of H3K9me and transposon derepression indicate that S-adenosylmethionine-dependent transmethylation is inhibited in mthfd1-1. Comparative analysis of DNA methylation revealed that the CMT3 and CMT2 pathways involving positive feedback with H3K9me are mostly affected. Our work highlights the sensitivity of epigenetic networks to one-carbon metabolism due to their common S-adenosylmethionine-dependent transmethylation and has implications for human MTHFD1-associated diseases

Estudio comparativo de los nuevos anticoagulantes orales

El tratamiento anticoagulante con Antagonistas de la Vitamina K (AVK) es muy complejo. Los nuevos anticoagulantes orales han supuesto una alternativa a los fármacos inhibidores de la vitamina K, presentando un mayor margen terapéutico así como una menor variabilidad intrae interindividual. Por otra parte, pueden administrarse a dosis fijas sin necesidad de una monitorización tan estrecha como requieren los AVK. Los nuevos anticoagulantes orales se clasifican en dos grupos atendiendo a su mecanismo de acción: inhibidores directos del factor X activado (FXa) (rivaroxabán, apixabán y edoxabán) y un inhibidor directo de la trombina (dabigatrán). Se han finalizado con resultados positivos diversos ensayos de fase III en profilaxis del tromboembolismo venoso en cirugía ortopédica, tratamiento del tromboembolismo venoso, o prevención del ictus en pacientes con fibrilación auricular. Para establecer una dosificación adecuada de estos fármacos, dado que las pruebas de laboratorio disponibles no son precisas ni permiten conocer el grado de anticoagulación, es necesario considerar otros factores como las interacciones farmacológicas y el estado de la función renal de cada paciente. En el futuro, las preferencias del paciente y las características farmacológicas serán relevantes para optimizar el tratamiento. Por todo ello, estos nuevos fármacos representan un nuevo paradigma en el tratamiento anticoagulante, aportando grandes ventajas, pero no exentos de inconvenientes

Hubble Space Telescope imaging of η Carinae

We present new high spatial resolution observations of the material around η Carinae obtained with the Hubble Space Telescope Wide Field/Planetary Camera. The star η Carinae is one of the most massive and luminous stars in our Galaxy, and has been episodically expelling significant quantities of gas over the last few centuries. The morphology of the bright central nebulosity (the homunculus) indicates that it is a thin shell with very well defined edges, and is clumpy on 0".2 (~10^(16)cm) scales. An extension to the northeast of the star {NN/NS using Walborn's [ApJL, 204, L17 ( 1976)] nomenclature} appears to be a stellar jet and its associated bow shock. The bow shock is notable for an intriguing series of parallel linear features across its face. The S ridge and the W arc appear to be part of a "cap" of emission located to the SW and behind the star. Together, the NE jet and the SW cap suggest that the symmetry axis for the system runs NE-SW rather than SE-NW, as previously supposed. Overall, the data indicate that the material around the star may represent an oblate shell with polar blowouts, rather than a bipolar flow

Expression of interleukin (IL)-2 and IL-7 receptors discriminates between human regulatory and activated T cells

Abnormalities in CD4+CD25+Foxp3+ regulatory T (T reg) cells have been implicated in susceptibility to allergic, autoimmune, and immunoinflammatory conditions. However, phenotypic and functional assessment of human T reg cells has been hampered by difficulty in distinguishing between CD25-expressing activated and regulatory T cells. Here, we show that expression of CD127, the α chain of the interleukin-7 receptor, allows an unambiguous flow cytometry–based distinction to be made between CD127lo T reg cells and CD127hi conventional T cells within the CD25+CD45RO+RA− effector/memory and CD45RA+RO− naive compartments in peripheral blood and lymph node. In healthy volunteers, peripheral blood CD25+CD127lo cells comprised 6.35 ± 0.26% of CD4+ T cells, of which 2.05 ± 0.14% expressed the naive subset marker CD45RA. Expression of FoxP3 protein and the CD127lo phenotype were highly correlated within the CD4+CD25+ population. Moreover, both effector/memory and naive CD25+CD127lo cells manifested suppressive activity in vitro, whereas CD25+CD127hi cells did not. Cell surface expression of CD127 therefore allows accurate estimation of T reg cell numbers and isolation of pure populations for in vitro studies and should contribute to our understanding of regulatory abnormalities in immunopathic diseases

Planetary camera observations of the central parsec of M32

Analysis of V band HST Planetary Camera images of the elliptical galaxy M32 shows that its nucleus is extremely dense and remains unresolved at even the HST diffraction limit. A combined approach of image deconvolution and model fitting is used to investigate the starlight distribution into limiting radii of 0".04 (0.14 pc at 700 kpc). The logarithmic slope of the brightness profile smoothly flattens from y= -1.2 at 3.4 pc to y= -0.5 at 0.34 pc; interior to this radius the profile is equally consistent with a singular µ(r)∝ r,^(-1/2) cusp or a small nonisothermal core with r_c<0.37 pc. The isophotes maintain constant ellipticity into tlle center, and there is no evidence for a central point source, disk, dust, or any other substructures. The cusp model implies central mass densities p_0 > 3 X 10^7 M_☉ pc^(-3) at the resolution limit and is consistent with a central M_• = 3 X 10^6 M_☉ black hole; the core model implies p_0≈4 X 10^6 M_☉ pc^(-3). From the viewpoint of long-term stability, we argue that a starlight cusp surrounding a central black hole is the more plausible interpretation of the observations. A core at the implied density and size without a black hole has a relaxation time of only ~7 X 10^7 yr and a short stellar oollision timescale implying wholesale stellar merging over the age of the universe. The core would be strongly vulnerable to collapse and concomitant runaway stellar merging. Collapse may lead to formation of a massive black hole in any case if it cannot be reversed by formation of a binary from high-mass merger products. Regardless of the ultimate fate of the core, however, structural evolution of the core will always be accompanied by strong evolution of the core population-the constant isophote shape and absence of a central color gradient appear to show that such evolution has not occurred. In contrast, the high velocities around a black hole imply long relaxation and stellar collision times for the cusp population compared to the age of the universe

Imaging of the gravitational lens system PG 1115+080 with the Hubble Space Telescope

This paper is the first of a series presenting observations of gravitational lenses and lens candidates, taken with the Wide Field/Planetary Camera (WFPC) of the Hubble Space Telescope (HST). We have resolved the gravitational lens system PG 1115 + 080 into four point sources and a red, extended object that is presumably the lens galaxy; we present accurate relative intensities, colors, and positions of the four images, and lower accuracy intensity and position of the lens galaxy, all at the epoch 1991.2. Comparison with earlier data shows no compelling evidence for relative intensity variations between the QSO components having so far been observed. The new data agree with earlier conclusions that the system is rather simple, and can be produced by the single observed galaxy. The absence of asymmetry in the HST images implies that the emitting region of the quasar itself has an angular radius smaller than about 10 milliarcsec (100 pc for H_0=50, q_0=0.5)