Direct Measurement of Calcium Transport across Chloroplast Inner-Envelope Vesicles1

The initial rate of Ca2+ movement across the inner-envelope membrane of pea (Pisum sativum L.) chloroplasts was directly measured by stopped-flow spectrofluorometry using membrane vesicles loaded with the Ca2+-sensitive fluorophore fura-2. Calibration of fura-2 fluorescence was achieved by combining a ratiometric method with Ca2+-selective minielectrodes to determine pCa values. The initial rate of Ca2+ influx in predominantly right-side-out inner-envelope membrane vesicles was greater than that in largely inside-out vesicles. Ca2+ movement was stimulated by an inwardly directed electrochemical proton gradient across the membrane vesicles, an effect that was diminished by the addition of valinomycin in the presence of K+. In addition, Ca2+ was shown to move across the membrane vesicles in the presence of a K+ diffusion potential gradient. The potential-stimulated rate of Ca2+ transport was slightly inhibited by diltiazem and greatly inhibited by ruthenium red. Other pharmacological agents such as LaCl3, verapamil, and nifedipine had little or no effect. These results indicate that Ca2+ transport across the chloroplast inner envelope can occur by a potential-stimulated uniport mechanism.

Urea-inducible Egr-1 transcription in renal inner medullary collecting duct (mIMCD3) cells is mediated by extracellular signal-regulated kinase activation.

Urea (200-400 milliosmolar) activates transcription, translation of, and trans-activation by the immediate-early gene transcription factor Egr-1 in a renal epithelial cell-specific fashion. The effect at the transcriptional level has been attributed to multiple serum response elements and their adjacent Ets motifs located within the Egr-1 promoter. Elk-1, a principal ternary complex factor and Ets domain-containing protein, is a substrate of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases. In the renal medullary mIMCD3 cell line, urea (200-400 milliosmolar) activated both ERK1 and ERK2 as determined by in-gel kinase assay and immune-complex kinase assay of epitope-tagged] ERK1 and ERK2. Importantly, urea did not affect abundance of either ERK. Urea-inducible Egr-1 transcription was a consequence of ERK activation because the ERK-specific inhibitor, PD98059, abrogated transcription from the murine Egr-1 promoter in a luciferase reported gene assay. In addition, activators of protein kinase A, including forskolin and 8-Br-cAMP, which are known to inhibit ERK-mediated events, also inhibited urea-inducible Egr-1 transcription. Furthermore, urea-inducible activation of the physiological ERK substrate and transcription factor, Elk-1, was demonstrated through transient cotransfection of a chimeric Elk-1/GAL4 expression plasmid and a GAL4-driven luciferase reporter plasmid. Taken together, these data indicate that, in mIMCD3 cells, urea activates ERKs and the ERK substrate, Elk-1, and that ERK inhibition abrogates urea-inducible Egr-1 transcription. These data are consistent with a model of urea-inducible renal medullary gene expression wherein sequential activation of ERKs and Elk-1 results in increased transcription of Egr-1 through serum response element/Ets motifs.

Resonant tectorial membrane motion in the inner ear: its crucial role in frequency tuning.

The tectorial membrane has long been postulated as playing a role in the exquisite sensitivity of the cochlea. In particular, it has been proposed that the tectorial membrane provides a second resonant system, in addition to that of the basilar membrane, which contributes to the amplification of the motion of the cochlear partition. Until now, technical difficulties had prevented vibration measurements of the tectorial membrane and, therefore, precluded direct evidence of a mechanical resonance. In the study reported here, the vibration of the tectorial membrane was measured in two orthogonal directions by using a novel method of combining laser interferometry with a photodiode technique. It is shown experimentally that the motion of the tectorial membrane is resonant at a frequency of 0.5 octave (oct) below the resonant frequency of the basilar membrane and polarized parallel to the reticular lamina. It is concluded that the resonant motion of the tectorial membrane is due to a parallel resonance between the mass of the tectorial membrane and the compliance of the stereocilia of the outer hair cells. Moreover, in combination with the contractile force of outer hair cells, it is proposed that inertial motion of the tectorial membrane provides the necessary conditions to allow positive feedback of mechanical energy into the cochlear partition, thereby amplifying and tuning the cochlear response.

Substructure of the inner core of the Earth.

The rationale is disclosed for a substructure within the Earth's inner core, consisting of an actinide subcore at the center of the Earth, surrounded by a subshell composed of the products of nuclear fission and radioactive decay. Estimates are made as to possible densities, physical dimensions, and chemical compositions. The feasibility for self-sustaining nuclear fission within the subcore is demonstrated, and implications bearing on the structure and geodynamic activity of the inner core are discussed.

Probes of the inner jets of blazars.

I review models for the "inner jet" in blazars, the section that connects the central engine with the radio jet. I discuss how the structure and physics of the inner jet can be explored using millimeter-wave VLBI (very-long-baseline radio interferometry) as well as multiwaveband observations of blazars. Flares at radio to gamma-ray frequencies should exhibit time delays at different wavebands that can test models for both the high-energy emission mechanisms and the nature of the inner jet in blazars.

Induction of cell proliferation in mammalian inner-ear sensory epithelia by transforming growth factor alpha and epidermal growth factor.

Regenerative proliferation occurs in the inner-ear sensory epithelial of warm-blooded vertebrates after insult. To determine how this proliferation is controlled in the mature mammalian inner ear, several growth factors were tested for effects on progenitor-cell division in cultured mouse vestibular sensory epithelia. Cell proliferation was induced in the sensory epithelium by transforming growth factor alpha (TGF-alpha) in a dose-dependent manner. Proliferation was also induced by epidermal growth factor (EGF) when supplemented with insulin, but not EGF alone. These observations suggest that stimulation of the EGF receptors by TGF-alpha binding, or EGF (plus insulin) binding, stimulates cell proliferation in the mature mammalian vestibular sensory epithelium.

Social Fan: un generador de redes sociales

Las redes sociales tienen un papel protagónico en la actualidad. Y es que hoy en día, no sólo se utilizan para la comunicación instantánea sino que también ponen a nuestra disposición otras muchas funcionalidades que nos hacen la vida más fácil tanto a nivel personal como profesional. Gracias a ellas, podemos reencontrarnos de una manera cómoda y sencilla con personas del pasado, compartir e intercambiar información en diferentes medios e incluso promover los productos y servicios que ofrezca una determinada empresa, logrando así un contacto más cercano con sus clientes y afiliados. Además en los últimos años las redes sociales también se han convertido en una nueva forma de búsqueda en Internet, de hecho se estima que podrían llegar a reemplazar a los motores de búsqueda. Según los datos obtenidos tras un estudio llevado a cabo por Entrepreneur, el 43% de los usuarios de internet utilizan las redes sociales como buscador de información o negocios1. El objetivo de este proyecto, denominado SocialFan, es el diseño y desarrollo de un generador de redes sociales. Con SocialFan el usuario podrá crear una red social totalmente a su gusto y sin necesidad de tener conocimientos previos informáticos, todo ello gracias a una interfaz muy sencilla y altamente personalizable. Cabe destacar también la existencia de un sistema de recomendación capaz de sugerir aquel contenido que pueda resultar del interés para cada uno de los usuarios. Con el fin de lograr el objetivo anterior, se han establecido relaciones entre los usuarios y poder encontrar así personas con personalidades y gustos similares. Señalar también que las redes sociales generadas a través de SocialFan cuentan con numerosas funcionalidades. La funcionalidad más importante consiste en la publicación del contenido que compone la red social. Este contenido puede ser aportado tan solo por el administrador de la red social o por todos losusuarios que la componen, tratándose en este último caso de una red colaborativa. Además los usuarios pueden valorar y comentar el contenido publicado por otros usuarios. Otra funcionalidad importante es el seguimiento de usuarios, el cual puede ser mutuo o no. Además estas redes sociales incorporan una búsqueda de usuarios y contenido que permite al usuario moverse con libertad por la página web sin necesidad de ceñirse a las recomendaciones realizadas. Sin embargo SocialFan no se limita a la generación de estas redes sociales sino que también permite la integración de la misma en una página web. Este caso puede ser más complicado de entender y podríamos preguntarnos ¿por qué un sitio web puede querer incorporar una red social? La respuesta a esta pregunta es que la interacción social nos permite conocer los gustos y opiniones de otros usuarios, lo cual aporta credibilidad y animan a los usuarios a interactuar y compartir sus experiencias. Para este proyecto se han implementado dos prototipos de uso del generador, creando dos redes sociales, la primera orientada al turismo en Madrid y la segunda orientada a los ejercicios de programación. Sin embargo, consideramos de gran importancia señalar que SocialFan no se limita a estos dos prototipos, sino que se trata de un proyecto muy extensible y genérico, lo que permite adaptarlo a muchos otros dominios, como podrían ser el mundo del arte, los deportes, las mascotas, etc. El proyecto se encuentra disponible vía web en los siguientes enlaces: http://container.fdi.ucm.es:20083/SocialFan http://container.fdi.ucm.es:20083/Madrid

Immunohistochemical evidence of synaptic retraction, cytoarchitectural remodeling, and cell death in the inner retina of the rat model of Oygen-Induced Retinopathy (OIR)

Purpose. Postnatal exposure to hyperoxia destroys the plexiform layers of the neonatal rat retina, resulting in significant electroretinographic anomalies. The purpose of this study was to identify the mechanisms at the origin of this loss. Methods. Sprague-Dawley (SD) and Long Evans (LE) rats were exposed to hyperoxia from birth to postnatal day (P) 6 or P14 and from P6 to P14, after which rats were euthanatized at P6, P14, or P60. Results. At P60, synaptophysin staining confirmed the lack of functional synaptic terminals in SD (outer plexiform layer [OPL]) and LE (OPL and inner plexiform layer [IPL]) rats. Uneven staining of ON-bipolar cell terminals with mGluR6 suggests that their loss could play a role in OPL thinning. Protein kinase C(PKC)-α and recoverin (rod and cone ON-bipolar cells, respectively) showed a lack of dendritic terminals in the OPL with disorganized axonal projections in the IPL. Although photoreceptor nuclei appeared intact, a decrease in bassoon staining (synaptic ribbon terminals) suggests limited communication to the inner retina. Findings were significantly more pronounced in LE rats. An increase in TUNEL-positive cells was observed in LE (inner nuclear layer [INL] and outer nuclear layer [ONL]) and SD (INL) rats after P0 to P14 exposure (425.3%, 102.2%, and 146.3% greater than control, respectively [P < 0.05]). Conclusions. Results suggest that cell death and synaptic retraction are at the root of OPL thinning. Increased TUNEL-positive cells in the INL confirm that cells die, at least in part, because of apoptosis. These findings propose a previously undescribed mechanism of cell death and synaptic retraction that are likely at the origin of the functional consequences of hyperoxia.

VdBH 222: a starburst cluster in the inner Milky Way

Context. It has been suggested that the compact open cluster VdBH 222 is a young massive distant object. Aims. We set out to characterise VdBH 222 using a comprehensive set of multi-wavelength observations. Methods. We obtained multi-band optical (UBVR) and near-infrared (JHKS) photometry of the cluster field, as well as multi-object and long-slit optical spectroscopy for a large sample of stars in the field. We applied classical photometric analysis, as well as more sophisticated methods using the CHORIZOS code, to determine the reddening to the cluster. We then plotted dereddened HR diagrams and determined cluster parameters via isochrone fitting. Results. We have identified a large population of luminous supergiants confirmed as cluster members via radial velocity measurements. We find nine red supergiants (plus one other candidate) and two yellow supergiants. We also identify a large population of OB stars. Ten of them are bright enough to be blue supergiants. The cluster lies behind ≈7.5 mag of extinction for the preferred value of RV = 2.9. Isochrone fitting allows for a narrow range of ages between 12 and 16 Ma. The cluster radial velocity is compatible with distances of ~6 and ~10 kpc. The shorter distance is inconsistent with the age range and Galactic structure. The longer distance implies an age ≈ 12 Ma and a location not far from the position where some Galactic models place the far end of the Galactic bar. Conclusions. VdBH 222 is a young massive cluster with a likely mass >20 000 M⊙. Its population of massive evolved stars is comparable to that of large associations, such as Per OB1. Its location in the inner Galaxy, presumably close to the end of the Galactic bar, adds to the increasing evidence for vigorous star formation in the inner regions of the Milky Way.

New galactic star clusters discovered in the VVV survey. Candidates projected on the inner disk and bulge

Context. VISTA Variables in the Vía Láctea (VVV) is one of six ESO Public Surveys using the 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the Galaxy. Aims. The primary motivation behind this work is to discover and analyze obscured star clusters in the direction of the inner Galactic disk and bulge. Methods. Regions of the inner disk and bulge covered by the VVV survey were visually inspected using composite JHKS color images to select new cluster candidates on the basis of apparent overdensities. DR1, DR2, CASU, and point spread function photometry of 10 × 10 arcmin fields centered on each candidate cluster were used to construct color–magnitude and color–color diagrams. Follow-up spectroscopy of the brightest members of several cluster candidates was obtained in order to clarify their nature. Results. We report the discovery of 58 new infrared cluster candidates. Fundamental parameters such as age, distance, and metallicity were determined for 20 of the most populous clusters.

The external morphology of the inner ear in bats from the phosphorites of Quercy / Walter Segall --.

v.33:no.4(1974)

Shawqī ʻalá al-Fanārī

[Aḥmad ibn ʻAbd Allāh Shawqī].

The truth lies within: the reconstructive value of inner livores in a homicide case.

Through the widespread use of postmortem computed tomography, inner livores of the lungs have become a frequently observed phenomenon in the field of forensic medicine. Yet their time-dependent development, notably in comparison with the widely studied external livores, remains poorly understood. We present a unique homicide case where the victim was discovered in supine position with correspondent external livores fixed exclusively on the rear side. Yet upon postmortem computed tomography, the victim presented pronounced inner livores within the depending dorsal areas of both lungs but also vertical sedimentation levels solely within the right lung, suggesting an initial right-hand side position and a postmortem re-positioning of the body. Interestingly, this was consistent with tangible hints of postmortem manipulation on-site. It is likely that this repositioning occurred sometime during the early postmortem interval (<6 h) as the external livores have completely rearranged to the final supine position. The presented case suggests different development patterns of inner and outer livores, highlighting the necessity for controlled studies that explore the formation and fixation processes of livor mortis in internal organs. A better understanding of these issues can prove useful in forensic examinations.