6,712 research outputs found
Expresión diferencial de genes en Pyropia columbina (Bangiales, Rhodophyta) bajo hidratación y desecación natural
Indexación: Web of Science; Scielo.RESUMEN. En Zonas Costeras rocosas, la desecación es gatillada porción Cambios Diarios en los Niveles de marea, y la Evidencia indica experimental de Me Distribución de las algas en la zona intermareal no está Relacionada estafa do palabra capacidad, párr tolerar la desecación. En Este Contexto, la Presencia de Pyropia columbina en la zona alta del intermareal sí Explica Por Su excepcional tolerancia fisiológica a la desecación. Este Estudio explora las Vías Metabólicas involucradas en la tolerancia a la desecación en P. columbina, un Través de la Caracterización de do transcriptoma Bajo Condiciones de hidratación contrastantes. Se obtuvó 1410 TER provenientes de dos Librerías de substracción de ADNc de frondas Naturalmente hidratadas y desecadas. Los transcriptomas de emba Librerías contienen transcritos de Diversas Rutas Metabólicas Relacionadas a la tolerancia. Entre el los transcritos expresados 15% estan involucrados en la Síntesis de Proteínas, do Procesamiento y degradacion, 14,4% Asociados un Fotosíntesis y cloroplasto, el 13,1% una mitocondrial Respiración and function, 10,6% al metabolism de la Pared Celular y 7,5% a la Actividad ANTIOXIDANTE, Proteínas chaperonas y factors de Defensa (catalasa, tiorredoxina, Proteínas de choque térmico, P450 citocromo). In Ambás Librerías sí DESTACA La Presencia De genes / Proteínas no descritos en algas. Proporciona Información This El Primer Trabajo molecular Que Estudia la tolerancia a desecación en P. columbina y Sus Resultados Ayudan a explicar los patrones clásicos de Distribución descritos párr algas en la zona intermareal.
Palabras clave: Pyropia, desecación porción Estrés, EST, macroalgas, transcriptómica, Proteínas.ABSTRACT. In rocky shores, desiccation is triggered by daily tide changes, and experimental evidence suggests that local distribution of algal species across the intertidal rocky zone is related to their capacity to tolerate desiccation. In this context, the permanence of Pyropia columbina in the high intertidal rocky zone is explained by its exceptional physiological tolerance to desiccation. This study explored the metabolic pathways involved in tolerance to desiccation in the Chilean P. columbina, by characterizing its transcriptome under contrasting conditions of hydration. We obtained 1,410 ESTs from two subtracted cDNA libraries in naturally hydrated and desiccated fronds. Results indicate that transcriptome from both libraries contain transcripts from diverse metabolic pathways related to tolerance. Among the transcripts differentially expressed, 15% appears involved in protein synthesis, processing and degradation, 14.4% are related to photosynthesis and chloroplast, 13.1% to respiration and mitochondrial function (NADH dehydrogenase and cytochrome c oxidase proteins), 10.6% to cell wall metabolism, and 7.5% are involved in antioxidant activity, chaperone and defense factors (catalase, thioredoxin, heat shock proteins, cytochrome P450). Both libraries highlight the presence of genes/proteins never described before in algae. This information provides the first molecular work regarding desiccation tolerance in P. columbina, and helps, to some extent, explaining the classical patterns of ecological distribution described for algae across the intertidal zone.http://ref.scielo.org/jm5rc
Leadership of Winter Mixed-Species Flocks by Tufted Titmice (Baeolophus bicolor): Are Titmice Passive Nuclear Species?
The tufted titmouse (Baeolophus bicolor, TUTI) is a nuclear species in winter foraging flocks whose antipredator calls are used to manage predation risk by diverse heterospecifics. We hypothesized that satellite species in mixed flocks follow TUTI (not vice versa), thereby defining the role of TUTI as a "passive" nuclear species. We followed 20 winter mixed-species flocks in North-Central Florida and assessed angular-angular correlations between overall flock, TUTI, and satellite species movement directions. We observed significant correlations between overall flock movement directions and those of TUTI, confirming our central prediction. Within flocks, however, fine-scale movement directions of satellite species were often more highly correlated with those of other satellites than with TUTI movements. We conclude that TUTI are passive nuclear species whose movements define flock paths, but within flocks, TUTI movements may have less influence on satellite movements than do other factors
Echelle long-slit optical spectroscopy of evolved stars
We present echelle long-slit optical spectra of a sample of objects evolving
off the AGB, most of them in the pre-planetary nebula (pPN) phase, obtained
with the ESI and MIKE spectrographs at Keck-II and Magellan-I, respectively.
The total wavelength range covered with ESI (MIKE) is ~3900 to 10900 A (~3600
to 7200A). In this paper, we focus our analysis mainly on the Halpha profiles.
Prominent Halpha emission is detected in half of the objects, most of which
show broad Halpha wings (up to ~4000 km/s). In the majority of the
Halpha-emission sources, fast, post-AGB winds are revealed by P-Cygni profiles.
In ~37% of the objects Halpha is observed in absorption. In almost all cases,
the absorption profile is partially filled with emission, leading to complex,
structured profiles that are interpreted as an indication of incipient post-AGB
mass-loss. All sources in which Halpha is seen mainly in absorption have F-G
type central stars, whereas sources with intense Halpha emission span a larger
range of spectral types from O to G. Shocks may be an important excitation
agent of the close stellar surroundings for objects with late type central
stars. Sources with pure emission or P Cygni Halpha profiles have larger J-K
color excess than objects with Halpha mainly in absorption, which suggests the
presence of warm dust near the star in the former. The two classes of profile
sources also segregate in the IRAS color-color diagram in a way that intense
Halpha-emitters have dust grains with a larger range of temperatures.
(abridged)Comment: 68 pages, 14 figures, accepted for publication in ApJS (abstract
abridged
SPIRITS 15c and SPIRITS 14buu: Two Obscured Supernovae in the Nearby Star-Forming Galaxy IC 2163
SPIRITS---SPitzer InfraRed Intensive Transients Survey---is an ongoing survey
of nearby galaxies searching for infrared (IR) transients with Spitzer/IRAC. We
present the discovery and follow-up observations of one of our most luminous
( mag, Vega) and red (
mag) transients, SPIRITS 15c. The transient was detected in a dusty spiral arm
of IC 2163 ( Mpc). Pre-discovery ground-based imaging revealed an
associated, shorter-duration transient in the optical and near-IR (NIR). NIR
spectroscopy showed a broad ( km s), double-peaked
emission line of He I at m, indicating an explosive origin. The NIR
spectrum of SPIRITS 15c is similar to that of the Type IIb SN 2011dh at a phase
of days. Assuming mag of extinction in SPIRITS 15c
provides a good match between their optical light curves. The IR light curves
and the extreme color cannot be explained using only a standard
extinction law. Another luminous ( mag) event, SPIRITS
14buu, was serendipitously discovered in the same galaxy. The source displays
an optical plateau lasting days, and we suggest a scenario similar
to the low-luminosity Type IIP SN 2005cs obscured by mag.
Other classes of IR-luminous transients can likely be ruled out in both cases.
If both events are indeed SNe, this may suggest of nearby
core-collapse SNe are missed by currently operating optical surveys.Comment: 19 pages, 7 Figures, 4 Table
Incorporation of phosphate into glycogen by glycogen synthase
The storage polymer glycogen normally contains small amounts of covalently attached phosphate as phosphomonoesters at C2, C3 and C6 atoms of glucose residues. In the absence of the laforin phosphatase, as in the rare childhood epilepsy Lafora disease, the phosphorylation level is elevated and is associated with abnormal glycogen structure that contributes to the pathology. Laforin therefore likely functions in vivo as a glycogen phosphatase. The mechanism of glycogen phosphorylation is less well-understood. We have reported that glycogen synthase incorporates phosphate into glycogen via a rare side reaction in which glucose-phosphate rather than glucose is transferred to a growing polyglucose chain (Tagliabracci et al. (2011) Cell Metab13, 274-282). We proposed a mechanism to account for phosphorylation at C2 and possibly at C3. Our results have since been challenged (Nitschke et al. (2013) Cell Metab17, 756-767). Here we extend the evidence supporting our conclusion, validating the assay used for the detection of glycogen phosphorylation, measurement of the transfer of (32)P from [β-(32)P]UDP-glucose to glycogen by glycogen synthase. The (32)P associated with the glycogen fraction was stable to ethanol precipitation, SDS-PAGE and gel filtration on Sephadex G50. The (32)P-signal was not affected by inclusion of excess unlabeled UDP before analysis or by treatment with a UDPase, arguing against the signal being due to contaminating [β-(32)P]UDP generated in the reaction. Furthermore, [(32)P]UDP did not bind non-covalently to glycogen. The (32)P associated with glycogen was released by laforin treatment, suggesting that it was present as a phosphomonoester. The conclusion is that glycogen synthase can mediate the introduction of phosphate into glycogen, thereby providing a possible mechanism for C2, and perhaps C3, phosphorylation
Ages and Metallicities of Hickson Compact Group Galaxies
Hickson Compact Groups (HCGs) constitute an interesting extreme in the range
of environments in which galaxies are located, as the space density of galaxies
in these small groups are otherwise only found in the centres of much larger
clusters. The work presented here uses Lick indices to make a comparison of
ages and chemical compositions of galaxies in HCGs with those in other
environments (clusters, loose groups and the field). The metallicity and
relative abundance of `-elements' show strong correlations with galaxy
age and central velocity dispersion, with similar trends found in all
environments. However, we show that the previously reported correlation between
-element abundance ratios and velocity dispersion disappears when a
full account is taken of the the abundance ratio pattern in the calibration
stars. This correlation is thus found to be an artifact of incomplete
calibration to the Lick system.
Variations are seen in the ranges and average values of age, metallicity and
-element abundance ratios for galaxies in different environments. Age
distributions support the hierarchical formation prediction that field galaxies
are on average younger than their cluster counterparts. However, the ages of
HCG galaxies are shown to be more similar to those of cluster galaxies than
those in the field, contrary to the expectations of current hierarchical
models. A trend for lower velocity dispersion galaxies to be younger was also
seen. This is again inconsistent with hierarchical collapse models, but is
qualitatively consistent with the latest N-body-SPH models based on monolithic
collapse in which star formation continues for many Gyr in low mass halos.Comment: 18 pages. Submitted for publication in MNRA
Empiema necessitans y osteomielitis aguda secundaria a una infección por Staphylo-coccus aureus resistente a meticilina asociado a la comunidad
Staphylococcus aureus is a well recognized pathogen with global distribution. In recent years community-associated, methicillin-resistant S. aureus has emerged as an increasing cause of severe infections among adults and children. Herein, a case is reported of a previously healthy, 19-month-old male, who presented with empyema necessitans and acute osteomyelitis due to a community-associated, methicillin-resistant, S. aureus strain. This report highlights the evolving epidemiology of S. aureus, as important pathogen in the community as well as the hospital setting, and the importance of establishing appropriate guidelines for diagnosis, management and surveillance of this public health problem.Staphylococcus aureus es uno de los principales patógenos a nivel mundial. Durante los últimos años se ha reportado un incremento en el número de casos de S. aureus resistente a la meticilina adquiridos en la comunidad, tanto en niños como en adultos de los Estados Unidos y de otras partes del mundo.En el presente trabajo reportamos un caso de empiema necessitans y osteomielitis aguda en un niño de 19 meses de edad previamente sano. El presente reporte resalta la cambiante epidemiología de S. aureus tanto en la comunidad como en el medio hospitalario y la importancia de establecer guías apropiadas para el diagnóstico, el tratamiento y la vigilancia de este relevante problema de salud pública
The fast declining Type Ia supernova 2003gs, and evidence for a significant dispersion in near-infrared absolute magnitudes of fast decliners at maximum light
We obtained optical photometry of SN 2003gs on 49 nights, from 2 to 494 days
after T(B_max). We also obtained near-IR photometry on 21 nights. SN 2003gs was
the first fast declining Type Ia SN that has been well observed since SN
1999by. While it was subluminous in optical bands compared to more slowly
declining Type Ia SNe, it was not subluminous at maximum light in the near-IR
bands. There appears to be a bimodal distribution in the near-IR absolute
magnitudes of Type Ia SNe at maximum light. Those that peak in the near-IR
after T(B_max) are subluminous in the all bands. Those that peak in the near-IR
prior to T(B_max), such as SN 2003gs, have effectively the same near-IR
absolute magnitudes at maximum light regardless of the decline rate Delta
m_15(B).
Near-IR spectral evidence suggests that opacities in the outer layers of SN
2003gs are reduced much earlier than for normal Type Ia SNe. That may allow
gamma rays that power the luminosity to escape more rapidly and accelerate the
decline rate. This conclusion is consistent with the photometric behavior of SN
2003gs in the IR, which indicates a faster than normal decline from
approximately normal peak brightness.Comment: 41 pages, 13 figures, to be published in the December, 2009, issue of
the Astronomical Journa
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