1,278 research outputs found
Análisis del impacto de la contaminación química sobre la herpetofauna: nuevos desafíos y aplicaciones prácticas
Durante el proceso de elaboración de esta revisión MEOS contó con
un contrato del Programa Juan de la Cierva (Ministerio de
Economía y Competitividad) y con una beca posdoctoral
de la Fundação para a Ciência e a Tecnologia de Portugal
(ref. SFRH/BPD/84716/2012). AES fue financiado por
una beca posdoctoral del Conselho Nacional de
Desenvolvimento Científico y Tecnológico – CNPq de
Brasil (ref. 370592/2013-1)Peer reviewe
Malaria parasite translocon structure and mechanism of effector export.
The putative Plasmodium translocon of exported proteins (PTEX) is essential for transport of malarial effector proteins across a parasite-encasing vacuolar membrane into host erythrocytes, but the mechanism of this process remains unknown. Here we show that PTEX is a bona fide translocon by determining structures of the PTEX core complex at near-atomic resolution using cryo-electron microscopy. We isolated the endogenous PTEX core complex containing EXP2, PTEX150 and HSP101 from Plasmodium falciparum in the 'engaged' and 'resetting' states of endogenous cargo translocation using epitope tags inserted using the CRISPR-Cas9 system. In the structures, EXP2 and PTEX150 interdigitate to form a static, funnel-shaped pseudo-seven-fold-symmetric protein-conducting channel spanning the vacuolar membrane. The spiral-shaped AAA+ HSP101 hexamer is tethered above this funnel, and undergoes pronounced compaction that allows three of six tyrosine-bearing pore loops lining the HSP101 channel to dissociate from the cargo, resetting the translocon for the next threading cycle. Our work reveals the mechanism of P. falciparum effector export, and will inform structure-based design of drugs targeting this unique translocon
Hydroponics as a valid tool to assess arsenic availability in mine soils
The low solubility of As in mine soils limits its phytoavailability. This makes the extrapolation of data obtained under hydroponic conditions unrealistic because the concentration in nutrient solution frequently overexposes plants to this metalloid. This work evaluates whether As supply in hydroponics resembles, to some extent, the As phytoavailable fraction in soils and the implications for phytoremediation. Phytotoxicity of As, in terms of biomass production, chlorophyll levels, and As concentrations in plants, was estimated and compared in both soils and hydroponics. In order for hydroponic conditions to be compared to soil conditions, plant exposure levels were measured in both cultures. Hydroponic As concentration ranging from 2-8 μM equated to the same plant organ concentrations from soils with 700-3000 mg kg-1. Total and extractable As fractions exceeded those values, but As concentrations in pore water were bellow them. According to our results (i) hydroponics should include doses in the range 0-10 μM As to allow the extrapolation of the results to As-polluted soils, and (ii) phytoextraction of As in mining sites will be limited by low As phytoavailabilityThis study was supported by the Spanish Ministry of Education and Science, project CTM 2007-66401-CO2/TECNO, and by Comunidad de Madrid, project S-0505/AMB/029
Abdu’l‐Bahá y la cuestión racial
El presente artículo tratará de comparar el discurso de ‘Abdu’l‐Bahá sobre la cuestión racial con el de sus contemporáneos en Occidente. Para ello se empleará como referencia el Primer Congreso Universal de las Razas, celebrado en Londres en 1911, que reunió a decenas de intelectuales y líderes sociales interesados en la convivencia racial y al que también fue invitado ‘Abdu’l‐Bahá. Se espera que este ejercicio comparativo muestre cómo, pese a compartir objetivos comunes, la perspectiva sobre la armonía racial del líder de la religión bahá’í y el de muchos de sus coetáneos era diametralmente opuesta y, por tanto, también lo eran sus propuestas para la transformación social
Plasma cytokines as potential biomarkers of kidney damage in patients with systemic lupus erythematosus
Background: Systemic lupus erythematosus is a heterogeneous chronic inflammatory autoimmune
disorder characterized by an exacerbated expression of cytokines and chemokines in
different tissues and organs. Renal involvement is a significant contributor to the morbidity
and mortality of systemic lupus erythematosus, and its diagnosis is based on renal biopsy,
an invasive procedure with a high risk of complications. Therefore, the development of
alternative, non-invasive diagnostic tests for kidney disease in patients with systemic lupus
erythematosus is a priority. Aim: To evaluate the plasma levels of a panel of cytokines and
chemokines using multiplex xMAP technology in a cohort of Colombian patients with active
and inactive systemic lupus erythematosus, and to evaluate their potential as biomarkers of
renal involvement. Results: Plasma from 40 systemic lupus erythematosus non-nephritis
patients and 80 lupus nephritis patients with different levels of renal involvement were analyzed
for 39 cytokines using Luminex xMAP technology. Lupus nephritis patients had significantly
increased plasma eotaxin, TNF-a, interleukin-17-a, interleukin-10, and interleukin-15
as compared to the systemic lupus erythematosus non-nephritis group. Macrophage-derived
chemokine, growth regulated oncogene alpha, and epidermal growth factor were significantly
elevated in systemic lupus erythematosus non-nephritis patients when compared to lupus
nephritis individuals. Plasma eotaxin levels allowed a discrimination between systemic lupus
erythematosus non-nephritis and lupus nephritis patients, for which we performed a receiver
operating characteristic curve to confirm. We observed a correlation of eotaxin levels with
active nephritis (Systemic Lupus Erythematosus Disease Activity Index). Our data indicate
that circulating cytokines and chemokines could be considered good predictors of renal
involvement in individuals with systemic lupus erythematosus
Abdu’l‐Bahá y la cuestión racial
This article will attempt to compare 'Abdu'l‐Bahá's discourse on the race question with that
of his contemporaries in the West. Accordingly, it will use as a reference the First Universal Races Congress, held in London in 1911 and which brought together dozens of intellectuals and social leaders interested in racial reconciliation and to which ‘Abdu'l‐Bahá was also invited to attend. It is hoped that this comparative exercise will show how, despite sharing common objectives, the perspective on racial harmony of the leader of the Bahá'í religion and that of many of his contemporaries was entirely different and, therefore, so were their proposals for social transformation.El presente artículo tratará de comparar el discurso de ‘Abdu’l‐Bahá sobre la cuestión racial con el de sus contemporáneos en Occidente. Para ello se empleará como referencia el Primer Congreso Universal de las Razas, celebrado en Londres en 1911, que reunió a decenas de intelectuales y líderes sociales interesados en la convivencia racial y al que también fue invitado ‘Abdu’l‐Bahá. Se espera que este ejercicio comparativo muestre cómo, pese a compartir objetivos comunes, la perspectiva sobre la armonía racial del líder de la religión bahá’í y el de muchos de sus coetáneos era diametralmente opuesta y, por tanto, también lo eran sus propuestas para la transformación social
Transcorneal Permeation in a Corneal Device of Non-Steroidal Anti-Inflammatory Drugs in Drug Delivery Systems
This work is focused on the ex vivo study of corneal permeation of two anti-inflammatory drugs: diclofenac, and flurbiprofen (as a model of hydrophilic and lipophilic drug, respectively) loaded to cyclodextrins or polymeric nanoparticles in order to determine differences in their corneal permeation against free drug or commercial eye drops. These studies were carried out in a corneal device designed and developed in our laboratory. In this work the habitual conditions for the permeation studies were modified to reproduce the behaviour when eye drops were administered. For this reason a new tetracompartmental pharmacokinetic model was developed. The complex formation of diclofenac with cyclodextrins and the flurbiprofen loaded to polymeric nanoparticles has been shown as effective procedures to remarkably increase the bioavailability of the anti-inflammatory drugs. The efficiency of polymeric nanoparticles of Poly (D-L lactic-coglycolyc) acid and poly-ε-caprolacton as intraocular targeting of NSAIDs has also been proved, being the latter polymer more effective to increase the flurbiprofen corneal permeation. The apparent corneal permeability coefficient of samples has been calculated getting a low permeation values for free drugs
Visual population receptive fields in people with schizophrenia have reduced inhibitory surrounds
People with schizophrenia (SZ) experience abnormal visual perception on a range of visual tasks, which have been linked to abnormal synaptic transmission and an imbalance between cortical excitation and inhibition. However differences in the underlying architecture of visual cortex neurons, which might explain these visual anomalies, have yet to be reported in vivo. Here, we probe the neural basis of these deficits by using functional MRI (fMRI) and population receptive field (pRF) mapping to infer properties of visually responsive neurons in people with SZ. We employed a Difference-of-Gaussian (DoG) model to capture the centre-surround configuration of the pRF, providing critical information about the spatial scale of the pRFs inhibitory surround. Our analysis reveals that SZ is associated with reduced pRF size in early retinotopic visual cortex as well as a reduction in size and depth of the inhibitory surround in V1, V2 and V4. We consider how reduced inhibition might explain the diverse range of visual deficits reported in SZ. SIGNIFICANCE STATEMENT: People with schizophrenia (SZ) experience abnormal perception on a range of visual tasks, which has been linked to abnormal synaptic transmission and an imbalance between cortical excitation/inhibition. However associated differences in the underlying architecture of visual cortex neurons have yet to be reported in vivo. We used fMRI and population receptive field (pRF) mapping to demonstrate that the fine-grained functional architecture of visual cortex in people with SZ differs from unaffected controls. SZ is associated with reduced pRF size in early retinotopic visual cortex, largely due to reduced inhibitory surrounds. An imbalance between cortical excitation and inhibition could drive such a change in the centre-surround pRF configuration, and ultimately explain the range of visual deficits experienced in SZ
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