Central ions and lateral asparagine/glutamine zippers stabilize the post-fusion hairpin conformation of the SARS coronavirus spike glycoprotein

AbstractThe coronavirus spike glycoprotein is a class I membrane fusion protein with two characteristic heptad repeat regions (HR1 and HR2) in its ectodomain. Here, we report the X-ray structure of a previously characterized HR1/HR2 complex of the severe acute respiratory syndrome coronavirus spike protein. As expected, the HR1 and HR2 segments are organized in antiparallel orientations within a rod-like molecule. The HR1 helices form an exceptionally long (120 Å) internal coiled coil stabilized by hydrophobic and polar interactions. A striking arrangement of conserved asparagine and glutamine residues of HR1 propagates from two central chloride ions, providing hydrogen-bonding “zippers” that strongly constrain the path of the HR2 main chain, forcing it to adopt an extended conformation at either end of a short HR2 α-helix

HPV distribution in cervical cancer in Portugal. A retrospective study from 1928 to 2005

Objectives: To determine human papillomavirus (HPV) types in invasive cervical cancer in Portugal. Methods: Cases diagnosed at the Institute Portugues de Oncologia de Lisboa de Francisco Gentil from the year 1928 to 2005 were selected for HPV DNA detection and genotyping using SPF10/DEIA/LiPA25 system. Results: Of the 1214 samples that were considered appropriate for HPV detection, 714 (58.8%; 95% CI: 56.0-61.6%) were positive for HPV DNA. This detection rate varied being lower in the first 3 decades (31.3%; 50.1%; 46.5%) and higher in the last decades (77.4-95.1%). This difference was due probably to the fixative used in the first three decades. The five most common types identified among HPV positive cases were HPV16 (58.2%), HPV18 (9.2%), HPV33 (6.2%), HPV45 (4.7%) and HPV31 (4.4%). Multiple infections were detected in 2.8% of the cases. HPV16 and 18 accounted for 67.4% of infections. There were no statistically significant changes of these types over the studied period. An increase at patient's age at diagnosis was observed in the last decades (p < 0.001). Conclusion: HPV16 and 18 accounts for almost 70% of cervical cancers in all 9 decades studied and support data that effective vaccination against these 2 types will reduce the cervical burden in Portuguese women

Human DNA decays faster with time than viral dsDNA: an analysis on HPV16 using pathology archive samples spanning 85 years

Background: Quality of the nucleic acids extracted from Formalin Fixed Paraffin Embedded (FFPE) samples largely depends on pre-analytic, fixation and storage conditions. We assessed the differential sensitivity of viral and human double stranded DNA (dsDNA) to degradation with storage time. Methods: We randomly selected forty-four HPV16-positive invasive cervical cancer (ICC) FFPE samples collected between 1930 and 1935 and between 2000 and 2004. We evaluated through qPCR the amplification within the same sample of two targets of the HPV16 L1 gene (69 bp, 134 bp) compared with two targets of the human tubulin-β gene (65 bp, 149 bp). Results: Both viral and human, short and long targets were amplified from all samples stored for 15 years. In samples archived for 85 years, we observed a significant decrease in the ability to amplify longer targets and this difference was larger in human than in viral DNA: longer fragments were nine times (CI 95% 2.6-35.2) less likely to be recovered from human DNA compared with 1.6 times (CI 95% 1.1-2.2) for viral DNA. Conclusions: We conclude that human and viral DNA show a differential decay kinetics in FFPE samples. The faster degradation of human DNA should be considered when assessing viral DNA prevalence in long stored samples, as HPV DNA detection remains a key biomarker of viral-associated transformation

Are the hosts of gamma-ray bursts sub-luminous and blue galaxies?

We present K-band imaging observations of ten gamma-ray burst (GRB) host galaxies for which an optical and/or radio afterglow associated with the GRB event was clearly identified. Data were obtained with the Very Large Telescope and New Technology Telescope at ESO (Chile), and with the Gemini-North telescope at Mauna Kea (Hawaii). Adding to our sample nine other GRB hosts with K-band photometry and determined redshifts published in the literature, we compare their observed and absolute K magnitudes as well as their R − K colours with those of other distant sources detected in various optical, nearinfrared, mid-infrared and submillimeter deep surveys. We find that the GRB host galaxies, most of them lying at 0.5 ≲ z ≲ 1.5, exhibit very blue colours, comparable to those of the faint blue star-forming sources at high redshift. They are sub-luminous in the K-band, suggesting a low stellar mass content. We do not find any GRB hosts harbouring R- and K-band properties similar to those characterizing the luminous infrared/submillimeter sources and the extremely red starbursts. Should GRBs be regarded as an unbiased probe of star-forming activity, this lack of luminous and/or reddened objects among the GRB host sample might reveal that the detection of GRB optical afterglows is likely biased toward unobscured galaxies. It would moreover support the idea that a large fraction of the optically-dark GRBs occur within dust-enshrouded regions of star formation. On the other hand, our result might also simply reflect intrinsic properties of GRB host galaxies experiencing a first episode of very massive star formation and characterized by a rather weak underlying stellar population. Finally, we compute the absolute B magnitudes for the whole sample of GRB host galaxies with known redshifts and detected at optical wavelengths. We find that the latter appear statistically even less luminous than the faint blue sources which mostly contributed to the B-band light emitted at high redshift. This indicates that the formation of GRBs could be favoured in particular systems with very low luminosities and, therefore, low metallicities. Such an intrinsic bias toward metal-poor environments would be actually consistent with what can be expected from the currently-favoured scenario of the “collapsar”. The forthcoming launch of the SWIFT mission at the end of 2003 will provide a dramatic increase of the number of GRB-selected sources. A detailed study of the chemical composition of the gas within this sample of galaxies will thus allow us to further analyse the potential effect of metallicity in the formation of GRB events.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica

Radio and IR study of the massive star-forming region IRAS 16353-4636

Context. With the latest infrared surveys, the number of massive protostellar candidates has increased significantly. New studies have posed additional questions on important issues about the formation, evolution, and other phenomena related to them. Complementary to infrared data, radio observations are a good tool to study the nature of these objects, and to diagnose the formation stage. Aims. Here we study the far-infrared source IRAS 16353-4636 with the aim of understanding its nature and origin. In particular, we search for young stellar objects (YSOs), possible outflow structure, and the presence of non-thermal emission. Methods. Using high-resolution, multi-wavelength radio continuum data obtained with the Australia Telescope Compact Array [The Australia Telescope Compact Array is funded by the Commonwealth of Australia for operation as a National Facility by CSIRO.],* we image IRAS 16353-4636 and its environment from 1.4 to 19.6 GHz, and derive the distribution of the spectral index at maximum angular resolution. We also present new JHKs photometry and spectroscopy data obtained at ESO NTT [Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (ESO Programme 073.D-0339, PI S. Chaty).].** 13CO and archival \ion{H}{i} line data, and infrared databases (MSX, GLIMPSE, MIPSGal) are also inspected. Results. The radio continuum emission associated with IRAS 16353-4636 was found to be extended (∼10 arcsec), with a bow-shaped morphology above 4.8 GHz, and a strong peak persistent at all frequencies. The NIR photometry led us to identify ten near-IR sources and classify them according to their color. We used the Hi line data to derive the source distance, and analyzed the kinematical information from the CO and NIR lines detected. Conclusions. We have identified the source IRAS 16353-4636 as a new protostellar cluster. In this cluster we recognized three distinct sources: a low-mass YSO, a high-mass YSO, and a mildly confined region of intense and non-thermal radio emission. We propose the latter corresponds to the terminal part of an outflow.Facultad de Ciencias Astronómicas y Geofísica

Very large telescope and Hubble Space Telescope observations of the host galaxy of GRB 990705

We present Very Large Telescope spectroscopic observations of the GRB 990705 host galaxy and highlight the benefits provided by the prompt phase features of gamma-ray bursts (GRBs) to derive the redshifts of the latter. In the host spectrum, we indeed detect an emission feature that we attribute to the [O II] λλ3726, 3729 doublet and derive an unambiguous redshift z = 0.8424 ± 0.0002 for this galaxy. This is in full agreement with the value z ∼ 0.86 ± 0.17 previously derived using a transient absorption edge discovered in the X-ray spectrum of GRB 990705. This burst is therefore the first GRB for which a reliable redshift was derived from the prompt phase emission itself, as opposed to redshift determinations performed using putative host galaxy emission lines or interstellar absorption lines in the GRB afterglows. Deep and high-resolution images of the host of GRB 990705 with the Space Telescope Imaging Spectrograph camera on board the Hubble Space Telescope reveal that the burst occurred in a nearly face-on Sc spiral galaxy typical of disk-dominated systems at 0.75 ≤ z ≤ 1. Assuming a cosmology with H0 = 65 km s-1 Mpc-1, Ωm = 0.3, and Ωλ = 0.7, we derive an absolute B magnitude MB = -21.75 for this galaxy and a star formation rate SFR ≈ 5-8 M⊙ yr-1. Finally, we discuss the implications of using X-ray transient features to derive GRB redshifts with larger burst samples and especially examine the case of short and dark long GRBs.Facultad de Ciencias Astronómicas y Geofísica

Doñana. Acta vertebrata. vol 21 (1)

Alimentación del visón americano (Mustela vison Schreber) en el rio Voltoya (Ávila, cuenca del Duero)Bone density and breaking stress in relation to consistent fracture position in fallow deer antlersHábitos alimentarios de la cabra montés (Capra pyrenaica) en zonas de distinta altitud de los puertos de Tortosa y Beceite. Referencia a la dieta de machos y hembrasDensidad y distribución de los nidos de la gaviota patiamarilla Larus cachinnans en las Islas Medes. Efectos asociados al hábitat y al descasteLa dieta alimenticia de Sorex minutus (Linnaeus, 1766) en el Pirineo occidental (Norte de la Penínsila Ibérica).Estimas del espacio vital y calidad del hábitat a lo largo del invierno en tres especies de peces (Cyprinidae) de un rio de régimen mediterráneoNew records of Bolivian mammals in the collection of the Estación Biológica de Doñana.Variabilidad intraespecífica de Labrus merula Linneo, 1758 (Pisces, Labridae) en la región sudatlántica de la Penísula ibericaMortalidad estacional de aves en una carretera del P.N. de L'Albufera de Valencia (E. de España)Presencia de Symphodus (Crenilabrus) ocellatus bertini (Pras, 1961) (Pisces, Labridae) en el sur de la Pemínsula Ibérica.Peer reviewe

Rationally designed azobenzene photoswitches for efficient two-photon neuronal excitation

Manipulation of neuronal activity using two-photon excitation of azobenzene photoswitches with near-infrared light has been recently demonstrated, but their practical use in neuronal tissue to photostimulate individual neurons with three-dimensional precision has been hampered by firstly, the low efficacy and reliability of NIR-induced azobenzene photoisomerization compared to one-photon excitation, and secondly, the short cis state lifetime of the two-photon responsive azo switches. Here we report the rational design based on theoretical calculations and the synthesis of azobenzene photoswitches endowed with both high two-photon absorption cross section and slow thermal back-isomerization. These compounds provide optimized and sustained two-photon neuronal stimulation both in light-scattering brain tissue and in Caenorhabditis elegans nematodes, displaying photoresponse intensities that are comparable to those achieved under one-photon excitation. This finding opens the way to use both genetically targeted and pharmacologically selective azobenzene photoswitches to dissect intact neuronal circuits in three dimensions

Investigación en color y calidad de alimentos

En esta ponencia se pretende presentar a los alumnos de la Escuela Politécnica Superior, las líneas de investigación del grupo Color y Calidad de Alimentos de la Universidad de Sevilla (AGR225, PAIDI) y las posibilidades de realizar Trabajos postdoctorales o continuar las salidas profesionales en el campo de industrias alimentarias.This paper tries to introduce to the student of Polytechnic School, the research lines of Color and Food Quality Group of the University of Seville (AGR225, PAIDI), and the possibilities of carrying out postdoctoral works or continuing the career in the field of food industries