339,962 research outputs found

    Transducer senses displacements of panels subjected to vibration

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    Inductive vibration sensor measures the surface displacement of nonferrous metal panels subjected to vibration or flutter. This transducer does not make any physical contact with the test panel when measuring

    Specificity of soil-borne pathogens on grain legumes

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    Specificity of soil-borne legume pathogens on pea, lupin and faba bean is currently investigated in fields where grain legumes are intensively cultivated. The study has so far lead to the following conclusions -Legume host-pathogen interactions demonstrate specificity of pathogen populations particularly in pea and lupin. -A. euteiches rot root was specified to pea in Denmark as root rot symptoms and oospores of the pathogen never were observed in roots of faba bean and lupin -F. oxysporum followed by F. solani were most frequently isolated from plant roots in plots highly infested by lupin pathogens -F. avenaceum was most frequently isolated from plant roots in plots highly infested by pea pathogens -Pathogenicity tests showed F. solani followed by F. avenaceum to be the most pathogenic Fusarium species on pea while F. avenaceum was the most destructive pathogen on faba bean. In contrast F. avenaceum was non-pathogenic on lupin

    Resistant and susceptible pea lines harbour different root-rot pathogens and antagonistic fungi

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    Disease resistance encompasses the mechanisms that allow a plant to withstand or ward off a pathogen. The molecular responses of plants under pathogen attack and the underlying genetics have been extensively studied. However, resistance is not only a trait defined by the warfare between pathogen and host. In fact, resistance is an emergent phenotype of the interactions between the microbial community and the host. Fungal root diseases threaten pea (Pisum sativum L.) cultivation, and therefore a valuable protein source and important crop in low-input farming systems. Resistance in current pea varieties against multiple root pathogens is lacking. In order to acknowledge the rhizosphere microbiome as an integral part of the environment, 261 pea genotypes were screened for resistance on naturally infested field soil in a pot-based experiment. Thereof, eight lines with contrasting disease levels were selected and tested on four soils with different disease pressure in a follow-up pot experiment. Along root rot assessments, pea pathogens (F. solani, F. oxysporum, F. avenaceum, A. euteiches, P. ultimum and D. pinodella) and arbuscular mycorrhizal fungi were quantified in diseased roots using qPCR assays. The amount of fungal DNA detected in the roots differed among the pea genotypes and the four soils and a significant pea genotype x soil interaction was evidenced for several pathogen species. For example, the quantity of F. avenaceum in the roots mostly depends on the soil (two-way ANOVA, p < 0.01) and differs significantly between pea genotypes (p = 0.013). F. oxysporum and F. solani quantities showed significant pea genotype x soil interactions (p < 0.01 for both species). Significant correlations were found between F. avenaceum and F. solani quantity and root rot index (rs = 0.38, p < 0.01 and rs = 0.56, p < 0.01, respectively ). On the other hand, F. oxysporum quantity shows no relationship with root rot (rs = 0.007, p = 0.95). These results suggest differential roles of the microbes in the pea root rot and highlight the importance of incorporating the complexity of the soil microbiome at early stages of resistance screenings and breeding efforts. Resistance breeding against root rot will be challenged by the fact that soil microbes interact with each other and the plant and that their composition varies between different soils. Further insights into plant-microbe interactions and emerging molecular plant breeding tools will fuel future plant breeding

    Biomass production, symbiotic nitrogen fixation and inorganic N use in dual and tri-component annual intercrops

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    The interspecific complementary and competitive interactions between pea (Pisum sativum L.), barley (Hordeum vulgare L.) and oilseed rape (Brassica napus L.), grown as dual and tri-component intercrops were assessed in a field study in Denmark. Total biomass production and N use at two levels of N fertilisation (0.5 and 4.0 g N/m2), were measured at five harvests throughout a growing season. All intercrops displayed land equivalent ratio values close to or exceeding unity, indicating complementary use of growth resources. Whereas both rape and barley responded positively to increased N fertilisation, irrespective of whether they were grown as sole- or intercrops, pea was strongly suppressed when grown in intercrop. Of the three crops barley was the strongest competitor for both soil and fertiliser N, rape intermediate and pea the weakest. Faster initial growth of barley than pea and rape gave barley an initial competitive advantage, an advantage that in the two dual intercrops was strengthened by the addition of N. Apparently the competitive superiority of barley was less strong in the tri-component intercrop, indicating that the impact of the dominantmay, through improved growth of both rape and pea, have been diminished through indirect facilitation. Interspecific competition had a promoting effect on the percent of nitrogen derived from N2 fixation of pea, and most so at the low N fertilisation level. Results indicate that the benefits achieved from the association of a legume and nonlegume, in terms of N2 fixed were greatest when pea was grown in association with rape as opposed to barley which could indicate that the benefits achieved from the association of a legume and nonlegume are partly lost if the nonlegume is too strong a competitor

    Engineered microenvironments for synergistic VEGF - integrin signalling during vascularization

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    We have engineered polymer-based microenvironments that promote vasculogenesis both in vitro and in vivo through synergistic integrin-growth factor receptor signalling. Poly(ethyl acrylate) (PEA) triggers spontaneous organization of fibronectin (FN) into nanonetworks which provide availability of critical binding domains. Importantly, the growth factor binding (FNIII12-14) and integrin binding (FNIII9-10) regions are simultaneously available on FN fibrils assembled on PEA. This material platform promotes synergistic integrin/VEGF signalling which is highly effective for vascularization events in vitro with low concentrations of VEGF. VEGF specifically binds to FN fibrils on PEA compared to control polymers (poly(methyl acrylate), PMA) where FN remains in a globular conformation and integrin/GF binding domains are not simultaneously available. The vasculogenic response of human endothelial cells seeded on these synergistic interfaces (VEGF bound to FN assembled on PEA) was significantly improved compared to soluble administration of VEGF at higher doses. Early onset of VEGF signalling (PLCÎł1 phosphorylation) and both integrin and VEGF signalling (ERK1/2 phosphorylation) were increased only when VEGF was bound to FN nanonetworks on PEA, while soluble VEGF did not influence early signalling. Experiments with mutant FN molecules with impaired integrin binding site (FN-RGE) confirmed the role of the integrin binding site of FN on the vasculogenic response via combined integrin/VEGF signalling. In vivo experiments using 3D scaffolds coated with FN and VEGF implanted in the murine fat pad demonstrated pro-vascularization signalling by enhanced formation of new tissue inside scaffold pores. PEA-driven organization of FN promotes efficient presentation of VEGF to promote vascularization in regenerative medicine applications

    The efficiency of a durum wheat-winter pea intercrop to improve yield and wheat grain protein concentration depends on N availability during early growth

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    Grain protein concentration of durum wheat is often too low, particularly in low-N-input systems. The aim of our study was to test whether a durum wheat - winter pea intercrop can improve relative yield and durum wheat grain protein concentration in low-N-input systems. A 2-year field experiment was carried out in SW France with different fertilizer-N levels to compare wheat (Triticum turgidum L., cv. Nefer) and pea (winter pea, Pisum sativum L., cv. Lucy) grown as sole crops or intercrops in a row-substitutive design. Without N fertilization or when N was applied late (N available until pea flowering less than about 120 kg N ha-1), intercrops were up to 19% more efficient than sole crops for yield and up to 32% for accumulated N, but were less efficient with large fertilizer N applications. Wheat grain protein concentration was significantly higher in intercrops than in sole crops (14% on average) because more N was remobilized into wheat grain due to: i) fewer ears per square metre in intercrops and ii) a similar amount of available soil N as in sole crops due to the high pea N2 fixation rate in intercrops (88% compared to 58% in sole crops)

    Dynamic analysis of competition and complementarity for light and N use to understand the yield and the protein content of a durum wheat-winter pea intercrop

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    In a previous paper (Bedoussac and Justes 2009, Plant and Soil DOI: 10.1007/s11104-009-0082-2), we showed that intercropping of durum wheat and winter pea increased the yield and protein concentration of durum wheat when early N availability was less than 120 kg N.ha-1. The aim of the present work was to understand these results by analysing intercrop species dynamics for growth, light and N acquisition. A 2-year field experiment was carried out in SW France with different fertilizer-N levels in order to compare wheat (Triticum turgidum L.) and pea (Pisum sativum L.) grown as sole crops and as an intercrop in a row substitutive design. The advantages of intercropping in low N conditions were mainly due to: i) better light use (up to 10%) thanks to species dynamic complementarity for leaf area index and height, ii) growth complementarity over time (higher growth rate of wheat until pea flowering and then of pea until wheat flowering), and iii) dynamic complementary N acquisition associated with better wheat N status throughout growth. Disadvantages, underlining poorer complementarity within the intercrop stand, were observed with ample available N in early growth. This induced higher cereal growth during winter which led to increase interspecies competition by reducing pea light absorption and consequently its biomass production

    Effects of palmitoylethanolamide in cocaine-induced behaviours

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    Aims. Cocaine addiction is a chronically relapsing disorder characterized by the compulsion to seek and take the drug. Previous investigations have demonstrated that several drugs of abuse, as cocaine, can alter the levels of lipid-based signalling molecules such as the N-acylethanolamines (NAEs). In addition, NAEs levels in the brain are sensitive to cocaine self-administration and extinction training. In this context, this study aimed to investigate the effect of repeated and acute palmitoylethanolamide (PEA), an endogenous NAE, on the behavioural effects of cocaine using mouse models of conditioned reward and psychomotor activation. Methods. Using male C57BL/6J mice, the ability of repeated PEA injections (1 or 10 mg/kg i.p) to modulate the development of a conditioned place preference (CPP) and behavioural sensitization (BS) induced by cocaine (20 mg/kg i.p.) was evaluated. In addition, the expression of cocaine-induced CPP and BS after acute PEA administration was also studied. Results. PEA (1 and 10 mg/kg i.p) significantly reduced the development of cocaine-induced BS, but did not modify the acquisition of cocaine-induced CPP. Furthermore, both doses of PEA were able to reduce the expression of BS and CPP. Conclusions. Altogether, these findings show that exogenous administration of PEA attenuated psychomotor activation and impaired the expression of CPP induced by cocaine. Our results may be relevant in order to understand the role of NAEs in the development and treatment of cocaine addiction.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. PSI2013-44901-P, AP2010-2044, FPU13/04819, CD12/0045

    Use of response surface methodology (RSM) to optimize pea starch-chitosan novel edible film formulation

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    The aim of this study was to develop an optimal formulation for preparation of an edible film from chitosan, pea starch and glycerol using response surface methodology (RSM). Three independent variables were assigned comprising chitosan (1-2%), pea starch (0.5-1.5%) and glycerol (0.5-1%) to design an empirical model best fit in physical, mechanical and barrier attributes. Impacts of independent variables on thickness, moisture content (MC), solubility, tensile strength (TS), elastic modulus (EM), elongation at break (EB) and water vapor permeability (WVP) of films were evaluated. All the parameters were found to have significant effects (p&lt;0.05) on physical and mechanical properties of film. The optimal formulation for preparation of edible film from chitosan, pea starch and glycerol was 1% chitosan, 1.5% pea starch and 0.5% glycerol. An edible film with good physical and mechanical properties can be prepared with this formulation and thus this formulation can be further applied for testing on coating for fruit and vegetables
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