107 research outputs found
Impact of DM direct searches and the LHC analyses on branon phenomenology
Dark Matter direct detection experiments are able to exclude interesting
parameter space regions of particle models which predict an important amount of
thermal relics. We use recent data to constrain the branon model and to compute
the region that is favored by CDMS measurements. Within this work, we also
update present colliders constraints with new studies coming from the LHC.
Despite the present low luminosity, it is remarkable that for heavy branons,
CMS and ATLAS measurements are already more constraining than previous analyses
performed with TEVATRON and LEP data.Comment: 17 pages, 2 figure
Clinical and immunological characteristics of tegumentary leishmaniasis cases in Bolivia
Background Tegumentary leishmaniasis (TL) is a parasitic disease that can present a cutaneous or mucocutaneous clinical form (CL and MCL, respectively). The disease is caused by different Leishmania species and transmitted by phlebotomine sand flies. Bolivia has one of the highest incidences of the disease in South America and the diagnosis is done by parasitological techniques. Our aim was to describe the clinical and immunological characteristics of CL and MCL patients attending the leishmaniasis reference center in Cochabamba, Bolivia, in order to gain updated clinical and epidemiological information, to evaluate the diagnostic methods used and to identify biomarkers related to clinical disease and its evolution. Methodology/Principal findings The study was conducted from September 2014 to November 2015 and 135 patients with lesions compatible with CL or MCL were included. Epidemiological and clinical data were collected using a semi-structured questionnaire. Two parasitological diagnostic methods were used: Giemsa-stained smears and culture of lesion aspirates. Blood samples obtained from participants were used to measure the concentrations of different cytokines. 59.2% (80/135) were leishmaniasis confirmed cases (CL: 71.3%; MCL: 28.7%). Sixty percent of the confirmed cases were positive by smears and 90.6% were positive by culture. 53.8% were primo-infections. Eotaxin and monokine induced by IFN-γ presented higher serum concentrations in the MCL clinical presentation compared to CL cases and no-cases. None of the cytokines presented different concentrations between primo-infections and secondary infections due to treatment failure. Conclusions/Significance In Bolivia, parasitological diagnosis remains the reference standard in diagnosis of leishmaniasis because of its high specificity, whereas the sensitivity varies over a wide range leading to loss of cases. Until more accurate tools are implemented, all patients should be tested by both smears and culture of lesion aspirates to minimize the risk of false negatives. Our results showed higher concentrations of several cytokines in MCL compared to CL, but no differences were observed between CL and no-cases. In addition, none of the cytokines differed between primary and secondary infections. These results highlight the need of further research to identify biomarkers of susceptibility and disease progression, in addition to looking at the local cellular immune responses in the lesions
Blood Parasite Load as an Early Marker to Predict Treatment Response in Visceral Leishmaniasis in Eastern Africa
Background: To expedite the development of new oral treatment regimens for visceral leishmaniasis (VL), there is a need for early markers to evaluate treatment response and predict long-term outcomes. Methods: Data from 3 clinical trials were combined in this study, in which Eastern African VL patients received various antileishmanial therapies. Leishmania kinetoplast DNA was quantified in whole blood with real-time quantitative polymerase chain reaction (qPCR) before, during, and up to 6 months after treatment. The predictive performance of pharmacodynamic parameters for clinical relapse was evaluated using receiver-operating characteristic curves. Clinical trial simulations were performed to determine the power associated with the use of blood parasite load as a surrogate endpoint to predict clinical outcome at 6 months. Results: The absolute parasite density on day 56 after start of treatment was found to be a highly sensitive predictor of relapse within 6 months of follow-up at a cutoff of 20 parasites/mL (area under the curve 0.92, specificity 0.91, sensitivity 0.89). Blood parasite loads correlated well with tissue parasite loads (ρ = 0.80) and with microscopy gradings of bone marrow and spleen aspirate smears. Clinical trial simulations indicated a > 80% power to detect a difference in cure rate between treatment regimens if this difference was high (> 50%) and when minimally 30 patients were included per regimen. Conclusions: Blood Leishmania parasite load determined by qPCR is a promising early biomarker to predict relapse in VL patients. Once optimized, it might be useful in dose finding studies of new chemical entities.This work was supported by the European Union Seventh Framework Programme Africoleish (grant number 305178); the World Health Organization—Special Programme for Research and Training in Tropical Diseases (WHO-TDR); the French Development Agency, France (grant number CZZ2062); UK aid, UK; the Federal Ministry of Education and Research through KfW, Germany; the Medicor Foundation, Liechtenstein; Médecins Sans Frontières, International; the Swiss Agency for Development and Cooperation (SDC), Switzerland (grant number 81017718); the Dutch Ministry of Foreign Affairs (DGIS), the Netherlands (grant number PDP15CH21); the French Ministry for Europe and Foreign Affairs (MEAE), France; The Rockefeller Foundation, USA; BBVA Foundation, Spain; the European Union—AfriKADIA project of the Second European and Developing Countries Clinical Trials Partnership Programme (EDCTP2) (grant number RIA2016S1635); and ZonMw/Dutch Research Council (NWO) Veni grant (project number 91617140 to T. P. C. D.).S
Extracellular cysteine disulfide bond break at Cys122 disrupts PIP2-dependent Kir2.1 channel function and leads to arrhythmias in Andersen-Tawil Syndrome
S
Extracellular Kir2.1C122Y Mutant Upsets Kir2.1-PIP2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome.
BACKGROUND
Andersen-Tawil syndrome type 1 is a rare heritable disease caused by mutations in the gene coding the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys (cysteine)122-to-Cys154 disulfide bond in the channel structure is crucial for proper folding but has not been associated with correct channel function at the membrane. We evaluated whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing its open state.
METHODS
We identified a Kir2.1 loss-of-function mutation (c.366 A>T; p.Cys122Tyr) in an ATS1 family. To investigate its pathophysiological implications, we generated an AAV9-mediated cardiac-specific mouse model expressing the Kir2.1C122Y variant. We employed a multidisciplinary approach, integrating patch clamping and intracardiac stimulation, molecular biology techniques, molecular dynamics, and bioluminescence resonance energy transfer experiments.
RESULTS
Kir2.1C122Y mice recapitulated the ECG features of ATS1 independently of sex, including corrected QT prolongation, conduction defects, and increased arrhythmia susceptibility. Isolated Kir2.1C122Y cardiomyocytes showed significantly reduced inwardly rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking. Molecular dynamics predicted that the C122Y mutation provoked a conformational change over the 2000-ns simulation, characterized by a greater loss of hydrogen bonds between Kir2.1 and phosphatidylinositol 4,5-bisphosphate than wild type (WT). Therefore, the phosphatidylinositol 4,5-bisphosphate-binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch clamping, the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing phosphatidylinositol 4,5-bisphosphate concentrations. In addition, the Kir2.1C122Y mutation resulted in channelosome degradation, demonstrating temporal instability of both Kir2.1 and NaV1.5 proteins.
CONCLUSIONS
The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential for the channel function. We demonstrate that breaking disulfide bonds in the extracellular domain disrupts phosphatidylinositol 4,5-bisphosphate-dependent regulation, leading to channel dysfunction and defects in Kir2.1 energetic stability. The mutation also alters functional expression of the NaV1.5 channel and ultimately leads to conduction disturbances and life-threatening arrhythmia characteristic of Andersen-Tawil syndrome type 1.The authors thank the Centro Nacional de Investigaciones Cardiovasculares (CNIC)
Viral Vectors Unit for producing the adeno-associated virus serotype 9. Confocal experiments were conducted at the CNIC Microscopy and Dynamic Imaging Unit. The
authors thank the CNIC Bioinformatics Unit for generating the in silico homology
modeling simulations, F-function analysis, and helpful discussions. The authors also
thank the Centro de Supercomputación de Galicia for the use of the Finis Terrae III
supercomputer to perform molecular dynamics studies. The CNIC was supported
by the Instituto de Salud Carlos III, the Ministerio de Ciencia, Innovación y Universidades, and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence
(grant CEX2020-001041-S funded by MICIU/AEI/10.13039/501100011033).
This work was supported by the National heart, Lung and Blood Institute under
National Institutes of Health (NIH) grant R01HL163943; the La Caixa Banking
Foundation project code HR18-00304 (grant LCF/PR/HR19/52160013); grants
PI-FIS-2020, PI20/01220, PI-FIS-2023, and PI23/01039 from the Instituto de Salud Carlos III and cofunded by the Fondo Europeo de Desarrollo Regional
(FEDER) and the European Union, respectively; grants PID2020-116935RB-I00
and BFU2016-75144-R funded by MICIU/AEI/10.13039/501100011033; the
Fundación La Marató de TV3 (736/C/2020) amb el suport de la Fundació La Marató
de TV3; the CIBER (Centro de Investigación Biomédica en Red) de Enfermedades
Cardiovasculares (grant CB16/11/00458); the European Union’s Horizon 2020
grant agreement GA-965286; and the Program S2022/BMD7229-CM ARCADIACM funded by the Comunidad de Madrid to J. Jalife; grant PID2021-126423OB-C22
(to M. Martín-Martínez) funded by MICIU/AEI/10.13039/501100011033; and European Regional Development Fund (ERDF) grant PID2022-137214OB-C22 (to
M. Gutierrez-Rodríguez) funded by MICIU/AEI/10.13039/501100011033. The
imaging studies were performed in the TRIMA@CNIC (Infraestructura de Imagen
Traslacional Avanzada del CNIC) node of the ICTS ReDIB (Infraestructuras Científicas y Técnicas Singulares: Red Distribuida de Imagen Biomédica) grant ICTS-2018-
04-CNIC-16 funded by MICIU/AEI/10.13039/501100011033 and ERDF, and
project EQC2018-005070-P funded by MICIU/AEI/10.13039/501100011033
and FEDER. A.I. Moreno-Manuel holds an formación profesional universitaria (FPU)
contract (FPU20/01569) from the Ministerio de Universidades. J.M. Ruiz Robles
holds an FPU contract (FPU22/03253) from the Ministerio de Universidades.
L.K. Gutiérrez holds an FPI contract (PRE2018-083530) from the Ministerio de
Economía y Competitividad de España cofunded by the Fondo Social Europeo, attached to project SEV-2015-0505-18-2. I. Martínez-Carrascoso holds a PFIS (Contratos predoctorales de formación en investigación en salud) contract (FI21/00243)
funded by Instituto de Salud Carlos III and the Fondo Social Europeo Plus cofunded
by the European Union. M.L. Vera-Pedrosa held contract PEJD-2019-PRE/BMD15982 funded by the Consejería de Educación e Investigación de la Comunidad de
Madrid y Fondo Social Europeo.S
Sward structure of marandu palisadegrass subjected to continuous stocking and nitrogen-induced rhythms of growth
Does the disturbance hypothesis explain the biomass increase in basin-wide Amazon forest plot data?
Positive aboveground biomass trends have been reported from old-growth forests across the Amazon basin and hypothesized to reflect a large-scale response to exterior forcing. The result could, however, be an artefact due to a sampling bias induced by the nature of forest growth dynamics. Here, we characterize statistically the disturbance process in Amazon old-growth forests as recorded in 135 forest plots of the RAINFOR network up to 2006, and other independent research programmes, and explore the consequences of sampling artefacts using a data-based stochastic simulator. Over the observed range of annual aboveground biomass losses, standard statistical tests show that the distribution of biomass losses through mortality follow an exponential or near-identical Weibull probability distribution and not a power law as assumed by others. The simulator was parameterized using both an exponential disturbance probability distribution as well as a mixed exponential–power law distribution to account for potential large-scale blowdown events. In both cases, sampling biases turn out to be too small to explain the gains detected by the extended RAINFOR plot network. This result lends further support to the notion that currently observed biomass gains for intact forests across the Amazon are actually occurring over large scales at the current time, presumably as a response to climate change
Functional differentiation between fish assemblages from forested and deforested streams
Genome of Herbaspirillum seropedicae Strain SmR1, a Specialized Diazotrophic Endophyte of Tropical Grasses
The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme—GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species
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