Molecular Hydrogen Kinematics in Cepheus A

We present the radial velocity structure of the molecular hydrogen outflows associated to the star forming region Cepheus A. This structure is derived from doppler shift of the H_2 v=1-0 S(1) emission line obtained by Fabry-Perot spectroscopy. The East and West regions of emission, called Cep A(E) and Cep A(W), show radial velocities in the range -20 to 0 km/s with respect to the molecular cloud. Cep A(W) shows an increasing velocity with position offset from the core indicating the existence of a possible accelarating machanism. Cep A(E) has an almost constant mean radial velocity of -18 km/s along the region although with a large dispersion in velocity, indicating the possibility of a turbulent outflow. A detailed analysis of the Cep A(E) region shows evidence for the presence of a Mach disk on that outflow. Also, we argue that the presence of a velocity gradient in Cep A(W) is indicative of a C-shock in this region. Following Riera et al. (2003), we analyzed the data using wavelet analysis to study the line width and the central radial velocity distributions. We found that both outflows have complex spatial and velocity structures characteristic of a turbulent flow.Comment: 24 pages, 15 figure

AGN in the CALIFA survey: X-ray detection of nuclear sources

A complete demographic of active galactic nuclei (AGN) is essential to understand the evolution of the Universe. Optical surveys estimate the population of AGN in the local Universe to be of $\sim$ 4%. However, these results could be biased towards bright sources, not affected by the host galaxy attenuation. An alternative method for detecting these objects is through the X-ray emission. In this work, we aim to complement the AGN population of the optical CALIFA survey (941 sources), by using X-ray data from Chandra, which provides the best spatial resolution to date, essential to isolate the nuclear emission from the host galaxy. We study a total of 138 sources with available data. We find 34 new bonafide AGN and 23 AGN candidates, which could increase the AGN population to 7-10\% among the CALIFA survey. X-rays are particularly useful for low-luminosity AGN since they are excluded by the criterion of large equivalent width of the $H\alpha$ emission line when applied to optical selections. Indeed, placing such a restrictive criteria might cause a loss of up to 70% of AGN sources. X-ray detected sources are preferentially located in the right side of the [$OIII$]/$H\beta$ versus [$NII$]/$H\alpha$ diagram, suggesting that this diagram might be the most reliable at classifying AGN sources. Our results support the idea that multi-wavelength studies are the best way to obtain a complete AGN population.Comment: 18 pages, 8 figures, 7 tables, 5 pages of supplementary online material available. Accepted for publication in MNRA

ARL15 modulates magnesium homeostasis through N-glycosylation of CNNMs

Cyclin M (CNNM1-4) proteins maintain cellular and body magnesium (Mg2+) homeostasis. Using various biochemical approaches, we have identified members of the CNNM family as direct interacting partners of ADP-ribosylation factor-like GTPase 15 (ARL15), a small GTP-binding protein. ARL15 interacts with CNNMs at their carboxyl-terminal conserved cystathionine-β-synthase (CBS) domains. In silico modeling of the interaction between CNNM2 and ARL15 supports that the small GTPase specifically binds the CBS1 and CNBH domains. Immunocytochemical experiments demonstrate that CNNM2 and ARL15 co-localize in the kidney, with both proteins showing subcellular localization in the endoplasmic reticulum, Golgi apparatus and the plasma membrane. Most importantly, we found that ARL15 is required for forming complex N-glycosylation of CNNMs. Overexpression of ARL15 promotes complex N-glycosylation of CNNM3. Mg2+ uptake experiments with a stable isotope demonstrate that there is a significant increase of 25Mg2+ uptake upon knockdown of ARL15 in multiple kidney cancer cell lines. Altogether, our results establish ARL15 as a novel negative regulator of Mg2+ transport by promoting the complex N-glycosylation of CNNMs.European Joint Program for Rare Diseases (EJPRD2019-40)Spanish Ministry of Science and Innovation and Universities (PGC2018-096049-B-I00)Junta de Andalucía (BIO-198, US-1254317 and US-1257019

Structural basis of direct and inverted DNA sequence repeat recognition by helix-turn-helix transcription factors

Some transcription factors bind DNA motifs containing direct or inverted sequence repeats. Preference for each of these DNA topologies is dictated by structural constraints. Most prokaryotic regulators form symmetric oligomers, which require operators with a dyad structure. Binding to direct repeats requires breaking the internal symmetry, a property restricted to a few regulators, most of them from the AraC family. The KorA family of transcriptional repressors, involved in plasmid propagation and stability, includes members that form symmetric dimers and recognize inverted repeats. Our structural analyses show that ArdK, a member of this family, can form a symmetric dimer similar to that observed for KorA, yet it binds direct sequence repeats as a non-symmetric dimer. This is possible by the 180° rotation of one of the helix-turn-helix domains. We then probed and confirmed that ArdK shows affinity for an inverted repeat, which, surprisingly, is also recognized by a non-symmetrical dimer. Our results indicate that structural flexibility at different positions in the dimerization interface constrains transcription factors to bind DNA sequences with one of these two alternative DNA topologies.FUNDING This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness [BIO2016-77883-C2-2- P and FIS2015-72574-EXP (AEI/FEDER, EU), to D.R.B., BFU2017-86378-P to F.dlC.] and by the Spanish Ministry of Science (MCI/AEI/FEDER,UE) [PGC2018-093885- BI00 and PID2021-122164NB-I00 to G.M., PID2020- 117028GB-I00 to D.R.B. and PID2019-110216GB-I00 to R. F-L.]. Conflict of interest statement. None declared. ACKNOWLEDGEMENTS Structural experiments were performed at the BL16 beamline at the ESRF European Synchrotron Radiation Facility (France) with the collaboration of EMBL staff, at the PROXIMA beamline at the SOLEIL Synchrotron (France) with the collaboration of SOLEIL staff, and at the XALOC beamline at the ALBA Synchrotron Radiation Facility (Spain) with the collaboration of ALBA staff. We are grateful to Carlos Revilla and Matilde Cabezas at the University of Cantabria for their technical assistance. Author contributions: R.F-L., F.dlC. and G.M. designed the research; L.G-M., R.R. and I.dC. performed the research; R.F-L., D.R.B., F.dlC and G.M analysed the data; and R.F.L., F.dlC. and G.M. wrote the manuscript. All authors reviewed the results and approved the final version of the manuscript

A triskelion-shaped saddle-helix hybrid nanographene

A unique rippled nanographene constituted by 52 fused rings is presented in which six out-of-plane motifs are fully fused into a triangular aromatic surface of ca. 2.5 nm size. Three units of an unprecedented fully lateral π-extended octabenzo[5]helicene together with three units of saddle-shaped heptagonal rings are combined in a single structure leading to a well-soluble warped nanographene. The two pairs of possible enantiomers have been isolated and their linear, non-linear and chiroptical properties evaluated, revealing an outstanding quantum yield and brightness values at low energy together with good chiroptical responses both in the absorption and emissionWe acknowledge the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ERC-2015-STG-677023) and the Ministerio de Economía y Competitividad (MINECO, Spain) (CTQ2015-70283- P, UNGR15-CE-3478, BES-2016-076371 and RyC-2013-12943). E.M. thanks the Fundação para a Ciência e a tecnologia (PTDC/NAN-MAT729317/2017 and PTDC/QUI-QFI/29319/2017). We thank the CSIRC-Alhambra from the University of Granada

AGN SURVEYS VIA OPTICAL VARIABILITY, X-RAY, AND MID-IR DETECTION IN HST FIELDS

RESUMEN En los campos de imágen profunda del Hubble (HST), los núcleos activos de galaxias (AGN) son seleccionados usando diversas técnicas en diferentes longitudes de onda. Este trabajo compara las muestras de AGN seleccionadas de los campos del Hubble a través de la variabilidadóptica, de los rayos-X y del mediano infrarrojo. Resultados recientes del campo HST-GOODS-South muestran que el 57% de los AGN seleccionados por su emsión conjunta en los rayos-X y en el mediano infrarrojo, varían en la región delóptico. Algunos AGN seleccionados sólo en rayos-X y unos cuantos de los seleccionados sólo del mediano infrarrojo también son variables en elóptico. Investigamos la naturaleza de los AGN que hemos identificado y el papel que juega el oscurecimiento al utilizar estas diferentes técnicas de selección. ABSTRACT AGN are identified in deep HST surveys via a number of selection techniques and wavelengths. This work compares the samples of AGN selected via optical variability, X-ray and mid-IR indicators in HST survey fields. Recent results from the HST GOODS-South field reveal that 57% of X-ray and mid-IR selected AGN are also optical variables. Several X-ray-only AGN are variables as well as a few mid-IR-only selected sources. We investigate the nature of the identified AGN and the role of obscuration among the various selection techniques

Microbial removal of weathered hydrocarbons by well adapted-bacteria

The effectiveness of bioremediation processes may be limited by the physical and chemical properties of the pollutant, such as availability, recalcitrance, concentration and weathering, among others. The aim of this work was to evaluate the removal of recalcitrant oil fractions (aliphatic-aromatic and asphaltenic fractions) from a weathered soil, by two bacteria adapted to a high concentration of oil hydrocarbons, isolated from a soil with a concentration of 227,000 mg of total petroleum hydrocarbons per kg soil. Kinetics of hydrocarbons removal by Bacillus coagulans and/or Serratia liquefasciens was performed in liquid culture for 168 h; hydrocarbons from soil as sole carbon and energy source (600 mg/l) were added and each of the microorganisms was inoculated for evaluation independently or as a mixed culture. The aromatic fraction was removed by B. coagulans at 330 mg/l; by S. liquefasciens at 130 mg/l; and by both microorganisms at 360 mg/l. The asphaltenic fraction was removed by B. coagulans at 23 mg/l; by S. liquefasciens at 15 mg/l; and by both microorganisms at 34 mg/l. Chromatographic analysis of the aliphatic-aromatic fraction showed the presence of branched aliphatic C6 to C26, polyaromatic substituted compounds of two and three rings, and heteroaromatic compounds of dibenzothiphene type. The compounds that were removed from the aliphatic-aromatic fraction were of all types in the range of C6 to C13.Keywords: Asphaltenes, aliphatic-aromatic fraction, weathered, biodegradationAfrican Journal of Biotechnology Vol. 12(9), pp. 941-94