Regulation der Oberflächenexpression von L-Typ-Ca2+-Kanälen im RPE

Das retinale Pigmentepithel (RPE) steht in direkter Interaktion mit Photorezeptoren. Die Ursache vieler degenerativer Erkrankungen des Auges ist daher mit einer Fehlfunktion vom RPE verbunden. Sekretorische Prozesse vieler Zelltypen werden über das Zusammenspiel spannungsabhängiger Kalzium- (Ca2+-) Kanäle und Rab- (Ras-related in brain) Proteinen, reguliert. Im RPE wird die Sekretion von Wachstumsfaktoren zur basolateralen Seite der Gefäßschicht über die Aktivierung von L-Typ-Ca2+-Kanälen vom Subtyp CaV1.3 sowie unteranderem von der GTPase, Rab27a, reguliert. Heterolog exprimierte CaV1.3/β3/α2δ1-Kanäle zeigten bei Koexpression mit Rab27a eine negative Spannungsabhängigkeit und eine um 70 % reduzierte Stromdichte. Die Oberflächenexpression von CaV1.3-Kanälen war bei Koexpression mit Rab27a nur um 10 % reduziert. Die Überexpression von Rab27a in einer humanen RPE-Zelllinie resultierte in einer Verschiebung der Spannungsabhängigkeit zu positiven Membranpotenzialen, einer Reduktion der Stromdichte endogener CaV1.3-Kanäle sowie einer verminderten Sekretion von vaskulären endothelialen Wachstumsfaktor (VEGF). Die Daten zeigen erstmals die direkte Modulation der Ca2+-Kanalaktivität durch Rab27a. Kennzeichnend für die Best`sche vitelliforme Makuladystrophie (BVMD), eine vererbbare autosomal-dominante Form der Makuladegeneration, ist der reduzierte Hellanstieg (LP) im Elektrookulogramm (EOG) von betroffenen Patienten. BVMD ist mit Mutationen im BEST1-Gen assoziiert. Das Genprodukt von BEST1, Bestrophin-1 (Best-1), ist ein integrales Protein der basolateralen Membran im RPE. Sowohl im EOG von Patienten nach Inhibierung von CaV1.3-Kanälen durch Dihydropyridin als auch im Elektroretinogramm im murinen CaV1.3-defizienten Modell ist ein reduzierter LP beschrieben worden. Die Hypothese, dass die Interaktion von Best-1 und CaV1.3-Kanälen von funktioneller Bedeutung für das RPE ist, und der schädigende Effekt von Mutationen im BEST1 durch die gestörte Interaktion des CaV1.3-Kanals und Best-1 entsteht, liegt somit nahe. Es wurden vier krankheitsassoziierte Missense-Mutationen im BEST1-Gen (R218C, T6P, F80L und F305S) untersucht. Alle Mutanten zeigten eine Interaktion mit dem CaV1.3/β4/α2δ-Kanalkomplex, obgleich die Effizienz in der Co-IP niedriger war als beim wildtypischen (WT) Best-1. Im heterologen Expressionssystem war die Stromdichte von CaV1.3-Kanälen in Anwesenheit der Mutanten reduziert und die Spannungsabhängigkeit in Anwesenheit von F80L und F305S verändert. Die verminderte Stromdichte korrelierte mit einer reduzierten Proteinlokalisation in der Plasmamembran, sowohl von mutanten Best-1 also auch von CaV1.3. In primären Schweine RPE-Zellen war mutantes Best-1 delokalisiert, was gleichzeitig in der Fehllokalisation von CaV1.3 und endogenem Best-1 resultierte. Zusätzlich waren T6P und F305S überwiegend apikal assoziiert. Die Ergebnisse konnten zusätzlich in humanen - aus induziert pluripotenten Stammzellen abgeleiteten - RPE-Zellen bestätigt werden. Die reduzierte Lokalisation von CaV1.3-Kanälen in der Plasmamembran könnte in einer verminderten Membranleitfähigkeit für Ca2+ resultieren, die wiederrum die sekretorische Aktivität vom RPE und die circadiane Regulation der Phagozytose modulieren könnte. Dies würde teilweise den reduzierten LP im EOG von BVMD-Patienten erklären

Geothermal Potential of the Brenner Base Tunnel—Initial Evaluations

Increasing demands on mobility and transport, but limited space above ground, lead to new traffic routes being built, even more underground in the form of tunnels. In addition to improving the traffic situation, tunnels offer the possibility of contributing to climate-friendly heating by indirectly serving as geothermal power plants. In this study, the geothermal potential of the future longest railway tunnel in the world, the Brenner Base Tunnel, was evaluated. At the Brenner Base Tunnel, warm water naturally flows from the apex of the tunnel towards the city of Innsbruck, Austria. In order to estimate its geothermal potential, hydrological data of discharge rates and temperatures were investigated and analyzed. The investigations indicated the highest geothermal potential in the summertime, while the lowest occurs during winter. It could be shown that these variations were a result of cooling during discharge through areas of low overburden (mid mountain range), where the tunnel atmosphere is increasingly influenced by the air temperatures outside the tunnel. Nevertheless, the calculations showed that there will be a usable potential after completion of the tunnel

Inhibition of Ca 2+ channel surface expression by mutant bestrophin‐1 in RPE cells

The BEST1 gene product bestrophin-1, a Ca2+-dependent anion channel, interacts with CaV1.3 Ca2+ channels in the retinal pigment epithelium (RPE). BEST1 mutations lead to Best vitelliform macular dystrophy. A common functional defect of these mutations is reduced trafficking of bestrophin-1 into the plasma membrane. We hypothesized that this defect affects the interaction partner CaV1.3 channel affecting Ca2+ signaling and altered RPE function. Thus, we investigated the protein interaction between CaV1.3 channels and bestrophin-1 by immunoprecipitation, CaV1.3 activity in the presence of mutant bestrophin-1 and intracellular trafficking of the interaction partners in confluent RPE monolayers. We selected four BEST1 mutations, each representing one mutational hotspot of the disease: T6P, F80L, R218C, and F305S. Heterologously expressed L-type channels and mutant bestrophin-1 showed reduced interaction, reduced CaV1.3 channel activity, and changes in surface expression. Transfection of polarized RPE (porcine primary cells, iPSC-RPE) that endogenously express CaV1.3 and wild-type bestrophin-1, with mutant bestrophin-1 confirmed reduction of CaV1.3 surface expression. For the four selected BEST1 mutations, presence of mutant bestrophin-1 led to reduced CaV1.3 activity by modulating pore-function or decreasing surface expression. Reduced CaV1.3 activity might open new ways to understand symptoms of Best vitelliform macular dystrophy such as reduced electro-oculogram, lipofuscin accumulation, and vision impairment

Análisis de economías regionales frutihortícolas del Departamento Colón, Provincia de Córdoba, caso: batata, vid, durazno. PRET Centro

El departamento Colón se encuentra ubicado en la región centro-norte de la provincia de Córdoba, cuenta con una superficie de 258.000 ha, lo que representa un 3,96% del total de la superficie provincial. Según datos del Censo Nacional Agropecuario 2002, la agricultura ocupa un 55% de la superficie, la ganadería un 38%, mientras los forestales, hortícolas y otras producciones regionales el 2,97% (Ministerio de Agricultura Córdoba, 2008). El Departamento Colón es un importante productor a nivel provincial de vid, durazno y batata. Según informantes calificados, la cantidad de superficie con frutales, papa y batata en el departamento asciende a las siguientes superficies: 250 ha de durazneros; 135 ha de vid; 20 ha de higueras; 15 ha con otros frutales; 250 ha de papa y 800 ha de batata. También en la localidad de Colonia Caroya existen aproximadamente 60 ha de verdura de hoja.  El informe que se presenta a continuación muestra los márgenes brutos actualizados para los cultivos de batata, durazno y vid representativos de la situación del productor del Departamento Colón, comprendido en el Proyecto Regional del Territorio Agrícola-Ganadero Central de la Provincia de Córdoba. Se considera el planteo técnico usual para la zona.INTA. CR Córdoba. EEA Manfredi.Fil: Barberis, Noelia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. Grupo Economía; ArgentinaFil: Cargnelutti, Magalí Andrea. Ministerio Agroindustria. Cambio Rural II; ArgentinaFil: Cordes, Diego Darío. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. AER Jesús María; ArgentinaFil: Giletta, Martin Alfredo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. Grupo Economía; ArgentinaFil: Grion, Adolfo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. AER Jesús María; ArgentinaFil: Hiza, L. Ministerio Agroindustria. Cambio Rural II; ArgentinaFil: Margonari, Vanina Magdalena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. AER Jesús María; ArgentinaFil: Paez Moron, Patricio Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. AER Jesús María; Argentin

The Shigella T3SS needle transmits a signal for MxiC release, which controls secretion of effectors

Type III secretion systems (T3SSs) are key determinants of virulence in many Gram-negative bacteria, including animal and plant pathogens. They inject ‘effector’ proteins through a ‘needle’ protruding from the bacterial surface directly into eukaryotic cells after assembly of a ‘translocator’ pore in the host plasma membrane. Secretion is a tightly regulated process, which is blocked until physical contact with a host cell takes place. Host cell sensing occurs through a distal needle ‘tip complex’ and translocators are secreted before effectors. MxiC, a Shigella T3SS substrate, prevents premature effector secretion. Here, we examine how the different parts of T3SSs work together to allow orderly secretion. We show that T3SS assembly and needle tip composition are not altered in an mxiC mutant. We find that MxiC not only represses effector secretion but that it is also required for translocator release. We provide genetic evidence that MxiC acts downstream of the tip complex and then the needle during secretion activation. Finally, we show that the needle controls MxiC release. Therefore, for the first time, our data allow us to propose a model of secretion activation that goes from the tip complex to cytoplasmic MxiC via the needle

Porous zinc and cobalt 2-nitroimidazolate frameworks with six-membered ring windows and a layered cobalt 2-nitroimidazolate polymorph

This work was supported by the European Community Seventh Framework Program (FP7/2007-2013) [grant agreement number 608490] (project M4CO2). A.O. would like to acknowledge the SCI for awarding a scholarship for her PhD research. G.M. thanks Institut Universitaire de France for its support. S.S. would like to thank the EPSRC for support EP/M506631/1. S.E.A would like to thank the Royal Society and Wolfson Foundation for a merit award.Polymorphs of Zn(2-nIm)2 (compound 1 ) and Co(2-nIm)2 (compounds 2 and 3 ) (2-nIm = 2-nitroimidazole) have been prepared by two routes: solvothermal synthesis and recrystallisation of ZIF-65(Zn/Co). Compounds 1 and 2 are isostructural, with a tetrahedrally-connected framework topology related to, but different from, that of tridymite (lonsdaleite). Single crystal X-ray diffraction analysis showed that in compound 1 (Pccn, Z = 8; a = 8.462(8) Å, b = 14.549(15) Å, c = 18.799(18) Å, V = 2314(4) Å3) there is rotational disorder for two of the three crystallographically-distinct linker types, which has been investigated computationally and by solid-state NMR spectroscopy. Detailed adsorption studies on a sample of 1 prepared by recrystallisation show 1.1 mmol g-1 uptake of CO2 at 0.1 bar (25 °C) with high affinity for CO2 over CH4 and N2 (adsorption enthalpies of 39.5, 26.0 and 18.5 kJ mol-1, respectively). A cobalt analogue (compound 2 ) with improved water stability (but lower porosity) has also been prepared. Changing the conditions of synthesis and recrystallisation gives rise to a cobalt 2-nitroimidazolate (Co(2-nIm)2, compound 3 ), which has a layered structure (I41/amd, a = 6.025(18) Å, c = 26.95(8) Å, V = 978.3(5) Å3) containing sheets of tetrahedrally-connected Co2+ cations composed of four membered rings, without porosity.PostprintPostprintPeer reviewe

Timing is everything: the regulation of type III secretion

Type Three Secretion Systems (T3SSs) are essential virulence determinants of many Gram-negative bacteria. The T3SS is an injection device that can transfer bacterial virulence proteins directly into host cells. The apparatus is made up of a basal body that spans both bacterial membranes and an extracellular needle that possesses a channel that is thought to act as a conduit for protein secretion. Contact with a host-cell membrane triggers the insertion of a pore into the target membrane, and effectors are translocated through this pore into the host cell. To assemble a functional T3SS, specific substrates must be targeted to the apparatus in the correct order. Recently, there have been many developments in our structural and functional understanding of the proteins involved in the regulation of secretion. Here we review the current understanding of protein components of the system thought to be involved in switching between different stages of secretion

The NANOGrav 15-year Data Set: Search for Anisotropy in the Gravitational-Wave Background

The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has reported evidence for the presence of an isotropic nanohertz gravitational wave background (GWB) in its 15 yr dataset. However, if the GWB is produced by a population of inspiraling supermassive black hole binary (SMBHB) systems, then the background is predicted to be anisotropic, depending on the distribution of these systems in the local Universe and the statistical properties of the SMBHB population. In this work, we search for anisotropy in the GWB using multiple methods and bases to describe the distribution of the GWB power on the sky. We do not find significant evidence of anisotropy, and place a Bayesian $95\%$ upper limit on the level of broadband anisotropy such that $(C_{l>0} / C_{l=0}) < 20\%$. We also derive conservative estimates on the anisotropy expected from a random distribution of SMBHB systems using astrophysical simulations conditioned on the isotropic GWB inferred in the 15-yr dataset, and show that this dataset has sufficient sensitivity to probe a large fraction of the predicted level of anisotropy. We end by highlighting the opportunities and challenges in searching for anisotropy in pulsar timing array data.Comment: 19 pages, 11 figures; submitted to Astrophysical Journal Letters as part of Focus on NANOGrav's 15-year Data Set and the Gravitational Wave Background. For questions or comments, please email [email protected]

The NANOGrav 12.5 yr Data Set: A Computationally Efficient Eccentric Binary Search Pipeline and Constraints on an Eccentric Supermassive Binary Candidate in 3C 66B

The radio galaxy 3C 66B has been hypothesized to host a supermassive black hole binary (SMBHB) at its center based on electromagnetic observations. Its apparent 1.05 yr period and low redshift (∼0.02) make it an interesting testbed to search for low-frequency gravitational waves (GWs) using pulsar timing array (PTA) experiments. This source has been subjected to multiple searches for continuous GWs from a circular SMBHB, resulting in progressively more stringent constraints on its GW amplitude and chirp mass. In this paper, we develop a pipeline for performing Bayesian targeted searches for eccentric SMBHBs in PTA data sets, and test its efficacy by applying it to simulated data sets with varying injected signal strengths. We also search for a realistic eccentric SMBHB source in 3C 66B using the NANOGrav 12.5 yr data set employing PTA signal models containing Earth term-only as well as Earth+pulsar term contributions using this pipeline. Due to limitations in our PTA signal model, we get meaningful results only when the initial eccentricity e 0 &lt; 0.5 and the symmetric mass ratio η &gt; 0.1. We find no evidence for an eccentric SMBHB signal in our data, and therefore place 95% upper limits on the PTA signal amplitude of 88.1 ± 3.7 ns for the Earth term-only and 81.74 ± 0.86 ns for the Earth+pulsar term searches for e 0 &lt; 0.5 and η &gt; 0.1. Similar 95% upper limits on the chirp mass are (1.98 ± 0.05) × 109 and (1.81 ± 0.01) × 109 M ☉. These upper limits, while less stringent than those calculated from a circular binary search in the NANOGrav 12.5 yr data set, are consistent with the SMBHB model of 3C 66B developed from electromagnetic observations

The NANOGrav 15-Year Data Set: Detector Characterization and Noise Budget

Pulsar timing arrays (PTAs) are galactic-scale gravitational wave detectors. Each individual arm, composed of a millisecond pulsar, a radio telescope, and a kiloparsecs-long path, differs in its properties but, in aggregate, can be used to extract low-frequency gravitational wave (GW) signals. We present a noise and sensitivity analysis to accompany the NANOGrav 15-year data release and associated papers, along with an in-depth introduction to PTA noise models. As a first step in our analysis, we characterize each individual pulsar data set with three types of white noise parameters and two red noise parameters. These parameters, along with the timing model and, particularly, a piecewise-constant model for the time-variable dispersion measure, determine the sensitivity curve over the low-frequency GW band we are searching. We tabulate information for all of the pulsars in this data release and present some representative sensitivity curves. We then combine the individual pulsar sensitivities using a signal-to-noise-ratio statistic to calculate the global sensitivity of the PTA to a stochastic background of GWs, obtaining a minimum noise characteristic strain of $7\times 10^{-15}$ at 5 nHz. A power law-integrated analysis shows rough agreement with the amplitudes recovered in NANOGrav's 15-year GW background analysis. While our phenomenological noise model does not model all known physical effects explicitly, it provides an accurate characterization of the noise in the data while preserving sensitivity to multiple classes of GW signals.Comment: 67 pages, 73 figures, 3 tables; published in Astrophysical Journal Letters as part of Focus on NANOGrav's 15-year Data Set and the Gravitational Wave Background. For questions or comments, please email [email protected]