171 research outputs found

    The interplay between zinc and iron homeostasis in Aspergillus fumigatus under zinc-replete conditions relies on the iron-mediated regulation of alternative transcription units of zafA and the basal amount of the ZafA zinc-responsiveness transcription factor

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    [EN] Aspergillus fumigatus is a saprophyte fungus that typically grows on organic decaying matter but can also parasitize immunosuppressed hosts. This is explained, in part, by its great ability to take up Zn2+ ions from living tissues, which is induced by the ZafA transcription factor. This study shows that the ZafA-mediated regulation of fungal growth is also influenced by iron availability and that A. fumigatus is well adapted to grow in zinc-limiting and zinc-replete media with Zn:Fe ratios lower in the former than in the latter. Accordingly, this indicates that iron availability appears to be more critical for fungal growth in zinc-replete than in zinc-limiting environments. Interestingly, the cross-regulation of zinc/iron homeostasis under zinc-replete conditions relies on an unprecedented iron-mediated regulation of different zafA transcription units that, along with a limited transcript translation, allows synthesizing the right basal amount of ZafA dependent on iron availability. We posit that this regulatory strategy has evolved in fungi as a mechanism to adjust zinc intake to iron availability under zinc-replete conditions. Thus, fungal growth is enhanced in zinc- and iron-replete media but restricted by reducing zinc intake under iron starvation to prevent the noxious side effects of an intracellular zinc excess during iron deficiency

    Sensitive response of GNP/epoxy coatings as strain sensors: Analysis of tensile-compressive and reversible cyclic behavior

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    The electromechanical performance and reversibility of sensitive GNP/epoxy strain sensors were experimentally and theoretically analyzed. Under tensile loads, the strain sensors showed lower sensitivity and more linearity than bulk sensors, behavior attributed to a slight preferential orientation of the GNPs along the in-plane direction. The Gauge Factor (GF) obtained was 9.1 ± 0.9 and 11 ± 1 for strain values up to 0.005 mm mm-1 and above 0.015 mm mm-1, respectively. In contrast, the electromechanical response when subjected to compressive strain is more complex and three different regions are distinguished: (I) diminution, (II) stabilization and (III) increase of the normalized electrical resistance. Here, GF under compressive loads was negative at low strain values (region I), being -13 ± 2, and positive at high strain (region III), with a value of 8 ± 1. Theoretical analysis revealed that at low strain, there is prevalence of in-plane tunneling mechanisms whereas at higher strain, the out of plane mechanisms dominate, explaining the apparently anomalous behavior at compressive loads. Additionally, strain sensors showed high reversibility with cyclic load in the electromechanical response, but under compressive forces, the loading-unloading electrical resistance curve was asymmetric due to the opening and closing of microcavities and defects in the vicinities of the GNPs.Ministerio de Economía y Competitividad MAT2016-78825-C2-1-RComunidad Autónoma de Madrid S2018/NMT-441

    Knockdown of Dystrophin Dp71 Impairs PC12 Cells Cycle: Localization in the Spindle and Cytokinesis Structures Implies a Role for Dp71 in Cell Division

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    The function of dystrophin Dp71 in neuronal cells remains to be established. Previously, we revealed the involvement of this protein in both nerve growth factor (NGF)-induced neuronal differentiation and cell adhesion by isolation and characterization of PC12 neuronal cells with depleted levels of Dp71. In this work, a novel phenotype of Dp71-knockdown cells was characterized, which is their delayed growth rate. Cell cycle analyses revealed an altered behavior of Dp71-depleted cells, which consists of a delay in G0/G1 transition and an increase in apoptosis during nocodazole-induced mitotic arrest. Dp71 associates with lamin B1 and β-dystroglycan, proteins involved in aspects of the cell division cycle; therefore, we compared the distribution of Dp71 with that of lamin B1 and β-dystroglycan in PC12 cells at mitosis and cytokinesis by means of immunofluorescence and confocal microscopy analysis. All of these three proteins exhibited a similar immunostaining pattern, localized at mitotic spindle, cleavage furrow, and midbody. It is noteworthy that a drastic decreased staining in mitotic spindle, cleavage furrow, and midbody was observed for both lamin B1 and β-dystroglycan in Dp71-depleted cells. Furthermore, we demonstrated the interaction of Dp71 with lamin B1 in PC12 cells by immunoprecipitation and pull-down assays, and importantly, we revealed that knockdown of Dp71 expression caused a marked reduction in lamin B1 levels and altered localization of the nuclear envelope protein emerin. Our data indicate that Dp71 is a component of the mitotic spindle and cytokinesis multi-protein apparatuses that might modulate the cell division cycle by affecting lamin B1 and β-dystroglycan levels

    An approach using highly sensitive carbon nanotube adhesive films for crack growth detection under flexural load in composite structures

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    Sensing capabilities of carbon nanotube (CNT)doped adhesive films under bending conditions were investigated. Standard Mode-II coupons and skin-stringer sub-elements were manufactured while their electrical resistance was monitored. Mode-II energy fracture was improved when adding CNTs in comparison to neat adhesive joints due to their toughening effect. Electrical monitoring showed a stable increase of the electrical resistance with crack length with lower sensitivity than Mode-I testing due to a lower crack opening effect. A good agreement was observed by comparing to theoretical estimations, indicating a uniform adhesive distribution inside the joint, confirmed by SEM analysis. Monitoring tests on skin-stringer sub-elements subjected to bending load showed a similar behavior but some sharp increases were observed, especially in the last stages of the test, due to a less uniform adhesive distribution in the central region. Therefore, the proposed technique shows a high potential and applicability for Structural Health Monitoring of composite structures

    Evaluation of sensitivity for detecting different failure modes of epoxy matrix composites doped with graphene nanoparticles

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    In recent years, the interest in monitoring the damage of composite materials by measuring the variation of electrical resistance is increasing because deformations and cracks generated in the structure produce changes in the electrical conductivity of the material. In this work, the structural integrity of glass fiber composite materials with epoxy matrix doped with graphene nanoparticles is evaluated under in plane tests (interlaminar shear tests and fracture propagation tests in mode I and II). The results demonstrated the ability of graphene nanoparticles to form conductive networks in the epoxy resin with auto-detection capability of deformation and damage. In the interlaminar shear tests, permanent changes in resistance were associated to strain and delamination produced during the test. In the case of fracture tests in mode I and II, the electrical resistance increased as the crack grew. The use of multiple electrodes has also allowed locating the area of damage generation in the material. Finally, the electrical response of discontinuities generated out of plane of the laminate was analyzed by means of cuts through the material

    High-Throughput System for the Early Quantification of Major Architectural Traits in Olive Breeding Trials Using UAV Images and OBIA Techniques

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    The need for the olive farm modernization have encouraged the research of more efficient crop management strategies through cross-breeding programs to release new olive cultivars more suitable for mechanization and use in intensive orchards, with high quality production and resistance to biotic and abiotic stresses. The advancement of breeding programs are hampered by the lack of efficient phenotyping methods to quickly and accurately acquire crop traits such as morphological attributes (tree vigor and vegetative growth habits), which are key to identify desirable genotypes as early as possible. In this context, an UAV-based high-throughput system for olive breeding program applications was developed to extract tree traits in large-scale phenotyping studies under field conditions. The system consisted of UAV-flight configurations, in terms of flight altitude and image overlaps, and a novel, automatic, and accurate object-based image analysis (OBIA) algorithm based on point clouds, which was evaluated in two experimental trials in the framework of a table olive breeding program, with the aim to determine the earliest date for suitable quantifying of tree architectural traits. Two training systems (intensive and hedgerow) were evaluated at two very early stages of tree growth: 15 and 27 months after planting. Digital Terrain Models (DTMs) were automatically and accurately generated by the algorithm as well as every olive tree identified, independently of the training system and tree age. The architectural traits, specially tree height and crown area, were estimated with high accuracy in the second flight campaign, i.e. 27 months after planting. Differences in the quality of 3D crown reconstruction were found for the growth patterns derived from each training system. These key phenotyping traits could be used in several olive breeding programs, as well as to address some agronomical goals. In addition, this system is cost and time optimized, so that requested architectural traits could be provided in the same day as UAV flights. This high-throughput system may solve the actual bottleneck of plant phenotyping of "linking genotype and phenotype," considered a major challenge for crop research in the 21st century, and bring forward the crucial time of decision making for breeders

    Estudio fenológico y caracterización morfológica de variedades tradicionales de manzano y melocotonero

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    Las variedades locales de frutales seleccionadas a lo largo de los años por los agricultores, son muy interesantes para preservar la biodiversidad y los recursos fitogenéticos, ya que presentan unas características organolépticas peculiares y un valor cultural irremplazable. En 2007 se inició un trabajo de recuperación de variedades tradicionales de frutales en Andalucía (Proyecto INIA, RF2007-00027- C06-05) que contempla su prospección, localización, recogida de material vegetal, caracterización morfológica y molecular, multiplicación, documentación y mantenimiento en colección. En este trabajo se han caracterizado morfológicamente mediante caracteres UPOV las flores, hojas y ramos de un año, de cinco variedades tradicionales de manzano (Malus x domestica Borkh.) y dos de melocotonero [Prunus persica (L) Batsch], no estudiadas con anterioridad. Se ha evaluado la floración en la campaña 2011 y se han realizado los fenogramas correspondientesMICINN, INIA y Fondos FEDE

    The complemented mutant (compl)Delta Bcstc7(niaD), in the STC7 of Botrytis cinerea led to the characterization of 11,12,13-tri-nor-eremophilenols derivatives

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    Botrytis cinerea has high potential for the production of specialized metabolites. The recent resequencing of the genome of the B05.10 strain using PacBio technology and the resulting update of the Ensembl Fungi (2017) database in the genome sequence have been instrumental in identifying new genes that could be involved in secondary metabolism. Thus, a new sesquiterpene cyclase (STC) coding gene (Bcstc7) has been included in the gene list from this phytopathogenic fungus. We recently constructed the null and complement transformants in STC7 which enabled us to functionally characterize this STC. Deletion of the Bcstc7 gene abolished (+)-4-epi-eremophilenol biosynthesis, and could then be re-established by complementing the null mutant with the Bcstc7 gene. Chemical analysis of the complemented transformant suggests that STC7 is the principal enzyme responsible for the key cyclization step of farnesyl diphosphate (FDP) to (+)-4-epi-eremophil-9-en-11-ols. A thorough analysis of the metabolites produced by two wild-type strains, B05.10 and UCA992, and the complemented mutant (compl)Delta Bcstc7(niaD), revealed the isolation and structural characterization of six 11,12,13-tri-nor-eremophilene derivatives, in addition to a large number of known eremophilen-11-ol derivatives. The structural characterization was carried out by extensive spectroscopic techniques. The biosynthesis of these compounds is explained by a retroaldol reaction or by dehydration and oxidative cleavage of C11-C13 carbons. This is the first time that this interesting family of degraded eremophilenols has been isolated from the phytopathogenous fungus B. cinerea.This research was supported by grants from MICINN-ERDF (RTI 2018-097356-B-C21 and -B-C22). Use of NMR facilities at the Servicio Centralizado de Ciencia y Tecnologia (SCCYT) of the University of Cadiz is acknowledged

    LDR brachytherapy offers superior tumor control to single-fraction HDR prostate brachytherapy: A prospective study

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    [Purpose]: To compare the clinical outcomes of single-fraction high-dose-rate (HDR) brachytherapy and single-fraction low-dose-rate (LDR) brachytherapy as the sole treatment for primary prostate cancer. [Material and Methods]: A quasi-randomized study that allocated, from March 2008 to February 2012, 129 low and intermediate risk prostate cancer patients to one single-fraction HDR of 19 Gy (61 patients) or to a 145 Gy 125I LDR permanent implant (68 patients. Biochemical relapse-free survival (bRFS) and overall survival (OS) were compared using the Kaplan–Meier method and Cox regression analysis. [Results]: After a median follow-up of 72 months in the HDR group, 26 patients relapsed, and after a median follow-up of 84 months in the LDR group, 7 patients relapsed (p < 0.0001). The 5-year bRFS was significantly better for the LDR group than for the HDR group (93.7% and 61.1%, respectively) (p < 0.0001). The 5-year OS also was significantly better in the LDR group (95.5% vs. 89.9%) (p = 0.0436). [Conclusions]: Permanent LDR prostate implant brachytherapy offers better clinical outcomes than single-fraction HDR for prostate cancer.Peer reviewe
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