201 research outputs found
Declining water resources in response to global warming and changes in atmospheric circulation patterns over southern Mediterranean France
Warming trends are responsible for an observed decrease
of water discharge in southern France (northwestern Mediterranean). Ongoing
climate change and the likely increase of water demand threaten the
availability of water resources over the coming decades. Drought indices
like the Reconnaissance Drought Index (RDI) are increasingly used in climate
characterization studies, but little is known about the relationships
between these indices, water resources, and the overall atmospheric
circulation patterns. In this study, we investigate the relationships
between the RDI, water discharge, and four atmospheric
teleconnection patterns (TPs) for six coastal river basins in southern
France, both for the historical period of the last 60 years and for a
worst-case climatic scenario (RCP8.5) reaching the year 2100. We combine
global and regional climate model (CGM and RCM, respectively) outputs with a
set of observed climatic and hydrological data in order to investigate the
past relationships between the RDI, water discharge, and TPs and to project their
potential evolution in space and time. Results indicate that annual water
discharge can be reduced by −49 % to −88 % by the end of the century under the
extreme climate scenario conditions. Due to unequal links with TPs, the
hydroclimatic evolution is unevenly distributed within the study area.
Indeed a clustering analysis performed with the RDI time series detects two
major climate clusters, separating the eastern and western part of the study
region. The former indicates stronger relationships with the Atlantic TPs
(e.g. the North Atlantic Oscillation (NAO) and the
Scandinavian Oscillation (Scand) patterns), whereas the latter is more closely
related to the Mediterranean TPs (Mediterranean Oscillation (MO) and Western Mediterranean Oscillation (WeMO)). The future climate
simulations predict an antagonistic evolution in both clusters which are
likely driven by decreasing trends of Scand and WeMO. The former provokes a
general tendency of lower P in both clusters during spring, summer, and
autumn, whereas the latter might partly compensate for this evolution by
enhanced precipitation in the eastern cluster during autumn and winter.
However, compared to observations, representation of the Mediterranean TPs
WeMO and MO in the considered climate models is less satisfactory compared
to the Atlantic TPs NAO and Scand, and further improvement of the model
simulations therefore requires better representations of the Mediterranean
TPs.</p
Neurochemical Changes in the Mouse Hippocampus Underlying the Antidepressant Effect of Genetic Deletion of P2X7 Receptors.
Recent investigations have revealed that the genetic deletion of P2X7 receptors (P2rx7) results in an antidepressant phenotype in mice. However, the link between the deficiency of P2rx7 and changes in behavior has not yet been explored. In the present study, we studied the effect of genetic deletion of P2rx7 on neurochemical changes in the hippocampus that might underlie the antidepressant phenotype. P2X7 receptor deficient mice (P2rx7-/-) displayed decreased immobility in the tail suspension test (TST) and an attenuated anhedonia response in the sucrose preference test (SPT) following bacterial endotoxin (LPS) challenge. The attenuated anhedonia was reproduced through systemic treatments with P2rx7 antagonists. The activation of P2rx7 resulted in the concentration-dependent release of [3H]glutamate in P2rx7+/+ but not P2rx7-/- mice, and the NR2B subunit mRNA and protein was upregulated in the hippocampus of P2rx7-/- mice. The brain-derived neurotrophic factor (BDNF) expression was higher in saline but not LPS-treated P2rx7-/- mice; the P2rx7 antagonist Brilliant blue G elevated and the P2rx7 agonist benzoylbenzoyl ATP (BzATP) reduced BDNF level. This effect was dependent on the activation of NMDA and non-NMDA receptors but not on Group I metabotropic glutamate receptors (mGluR1,5). An increased 5-bromo-2-deoxyuridine (BrdU) incorporation was also observed in the dentate gyrus derived from P2rx7-/- mice. Basal level of 5-HT was increased, whereas the 5HIAA/5-HT ratio was lower in the hippocampus of P2rx7-/- mice, which accompanied the increased uptake of [3H]5-HT and an elevated number of [3H]citalopram binding sites. The LPS-induced elevation of 5-HT level was absent in P2rx7-/- mice. In conclusion there are several potential mechanisms for the antidepressant phenotype of P2rx7-/- mice, such as the absence of P2rx7-mediated glutamate release, elevated basal BDNF production, enhanced neurogenesis and increased 5-HT bioavailability in the hippocampus
Identification of vehicle related risk factors, deliverable 6.1 of the H2020 project SafetyCube
The present Deliverable (D6.1) describes the identification and evaluation of vehicle related risk
factors. It outlines the results of Task 6.1 of Work Package 6 (WP6) of SafetyCube, which aimed to
identify and evaluate vehicle related risk factors and related road safety problems by (i) presenting a
taxonomy of vehicle related risks, (ii) identifying “hot topics” of concern for relevant stakeholders
and (iii) evaluating the relative importance for road safety outcomes (crash risk, crash frequency and
severity etc.) within the scientific literature for each identified risk factor. To reach this objective,
Task 6.1 has initially exploited current knowledge (e.g. existing studies) and existing accident data
(macroscopic and in-depth) in order to quantify scenarios (defined in Work Package 8) related to the
vehicle element. This information will help further on in WP6 to identify countermeasures for
addressing these risk factors and finally to undertake an assessment of the effects of these
countermeasures (...continues)
A Two-Gene Balance Regulates Salmonella Typhimurium Tolerance in the Nematode Caenorhabditis elegans
Lysozymes are antimicrobial enzymes that perform a critical role in resisting infection in a wide-range of eukaryotes. However, using the nematode Caenorhabditis elegans as a model host we now demonstrate that deletion of the protist type lysozyme LYS-7 renders animals susceptible to killing by the fatal fungal human pathogen Cryptococcus neoformans, but, remarkably, enhances tolerance to the enteric bacteria Salmonella Typhimurium. This trade-off in immunological susceptibility in C. elegans is further mediated by the reciprocal activity of lys-7 and the tyrosine kinase abl-1. Together this implies a greater complexity in C. elegans innate immune function than previously thought
Invariance of the essential spectra of operator pencils
The essential spectrum of operator pencils with bounded coefficients in a Hilbert space is studied. Sufficient conditions in terms of the operator coefficients of two pencils are derived which guarantee the same essential spectrum. This is done by exploiting a strong relation between an operator pencil and a specific linear subspace (linear relation)
Complete Killing of Caenorhabditis elegans by Burkholderia pseudomallei Is Dependent on Prolonged Direct Association with the Viable Pathogen
Background: Burkholderia pseudomallei is the causative agent of melioidosis, a disease of significant morbidity and mortality in both human and animals in endemic areas. Much remains to be known about the contributions of genotypic variations within the bacteria and the host, and environmental factors that lead to the manifestation of the clinical symptoms of melioidosis. Methodology/Principal Findings: In this study, we showed that different isolates of B. pseudomallei have divergent ability to kill the soil nematode Caenorhabditis elegans. The rate of nematode killing was also dependent on growth media: B. pseudomallei grown on peptone-glucose media killed C. elegans more rapidly than bacteria grown on the nematode growth media. Filter and bacteria cell-free culture filtrate assays demonstrated that the extent of killing observed is significantly less than that observed in the direct killing assay. Additionally, we showed that B. pseudomallei does not persistently accumulate within the C. elegans gut as brief exposure to B. pseudomallei is not sufficient for C. elegans infection. Conclusions/Significance: A combination of genetic and environmental factors affects virulence. In addition, we have also demonstrated that a Burkholderia-specific mechanism mediating the pathogenic effect in C. elegans requires proliferating B
Erythropoietic protoporphyria without skin symptoms-you do not always see what they feel
Erythropoietic protoporphyria (EPP) is an inherited disorder of the porphyrin metabolism that often remains undiagnosed in children. We report on a 4-year-old girl who had been suffering for 1 year from recurrent painful crises affecting her hands, feet, and nose following sun exposure. Objective skin lesions were absent until the age of 6. Porphyrin analysis revealed elevated free erythrocyte protoporphyrin (FEP) levels confirming the diagnosis of EPP. This illustrates that skin lesions might be completely absent in children affected with EPP, a fact that has only been reported once previously. Because EPP can manifest with few and unspecific cutaneous symptoms or no skin lesions at all, like in this patient, the diagnosis of EPP might be delayed or missed. EPP should be excluded in all photosensitive children, especially when discomfort is disproportionate to the extent of the cutaneous lesions. The clinic, pathophysiology, diagnosis, complications, and therapy of EPP are discussed
Metabotyping of docosahexaenoic acid - Treated alzheimer's disease cell model
10.1371/journal.pone.0090123PLoS ONE92-POLN
GATA Transcription Factor Required for Immunity to Bacterial and Fungal Pathogens
In the past decade, Caenorhabditis elegans has been used to dissect several genetic pathways involved in immunity; however, little is known about transcription factors that regulate the expression of immune effectors. C. elegans does not appear to have a functional homolog of the key immune transcription factor NF-κB. Here we show that that the intestinal GATA transcription factor ELT-2 is required for both immunity to Salmonella enterica and expression of a C-type lectin gene, clec-67, which is expressed in the intestinal cells and is a good marker of S. enterica infection. We also found that ELT-2 is required for immunity to Pseudomonas aeruginosa, Enterococcus faecalis, and Cryptococcus neoformans. Lack of immune inhibition by DAF-2, which negatively regulates the FOXO transcription factor DAF-16, rescues the hypersusceptibility to pathogens phenotype of elt-2(RNAi) animals. Our results indicate that ELT-2 is part of a multi-pathogen defense pathway that regulates innate immunity independently of the DAF-2/DAF-16 signaling pathway
MISC-1/OGC Links Mitochondrial Metabolism, Apoptosis and Insulin Secretion
We identified MISC-1 (Mitochondrial Solute Carrier) as the C. elegans orthologue of mammalian OGC (2-oxoglutarate carrier). OGC was originally identified for its ability to transfer α-ketoglutarate across the inner mitochondrial membrane. However, we found that MISC-1 and OGC are not solely involved in metabolic control. Our data show that these orthologous proteins participate in phylogenetically conserved cellular processes, like control of mitochondrial morphology and induction of apoptosis. We show that MISC-1/OGC is required for proper mitochondrial fusion and fission events in both C. elegans and human cells. Transmission electron microscopy reveals that loss of MISC-1 results in a decreased number of mitochondrial cristae, which have a blebbed appearance. Furthermore, our pull-down experiments show that MISC-1 and OGC interact with the anti-apoptotic proteins CED-9 and Bcl-xL, respectively, and with the pro-apoptotic protein ANT. Knock-down of misc-1 in C. elegans and OGC in mouse cells induces apoptosis through the caspase cascade. Genetic analysis suggests that MISC-1 controls apoptosis through the physiological pathway mediated by the LIN-35/Rb-like protein. We provide genetic and molecular evidence that absence of MISC-1 increases insulin secretion and enhances germline stem cell proliferation in C. elegans. Our study suggests that the mitochondrial metabolic protein MISC-1/OGC integrates metabolic, apoptotic and insulin secretion functions. We propose a novel mechanism by which mitochondria integrate metabolic and cell survival signals. Our data suggest that MISC-1/OGC functions by sensing the metabolic status of mitochondria and directly activate the apoptotic program when required. Our results suggest that controlling MISC-1/OGC function allows regulation of mitochondrial morphology and cell survival decisions by the metabolic needs of the cell
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