A non-targeted metabolomics study on Xylella fastidiosa infected olive plants grown under controlled conditions

In the last decade, the bacterial pathogen Xylella fastidiosa has devastated olive trees throughout Apulia region (Southern Italy) in the form of the disease called “Olive Quick Decline Syndrome” (OQDS). This study describes changes in the metabolic profile due to the infection by X. fastidiosa subsp. pauca ST53 in artificially inoculated young olive plants of the susceptible variety Cellina di Nardò. The test plants, grown in a thermo-conditioned greenhouse, were also co-inoculated with some xylem-inhabiting fungi known to largely occur in OQDS-affected trees, in order to partially reproduce field conditions in terms of biotic stress. The investigations were performed by combining NMR spectroscopy and MS spectrometry with a non-targeted approach for the analysis of leaf extracts. Statistical analysis revealed that Xylella-infected plants were characterized by higher amounts of malic acid, formic acid, mannitol, and sucrose than in Xylella-non-infected ones, whereas it revealed slightly lower amounts of oleuropein. Attention was paid to mannitol which may play a central role in sustaining the survival of the olive tree against bacterial infection. This study contributes to describe a set of metabolites playing a possible role as markers in the infections by X. fastidiosa in olive

Facile and fast synthesis of highly ordered L10-FeNi nanoparticles

The chemically ordered L1(0)-FeNi alloy is a promising candidate for next generation rare-earth-free permanent magnets, which can revolutionize the high-performance magnets market currently dominated by Nd-Fe-B. Despite many efforts, the experimental results fall short of theoretical predictions, and current approaches are not suitable for industrial implementation. In this work, we propose an innovative and efficient synthesis method that exploits the natural order of a crystalline Ni/Fe complex, which closely mimics the atomic organization in the L1(0) structure, to drive the formation of the ordered phase. By low-temperature reduction of the complex salt, carbon coated aggregates of FeNi alloy nanoparticles (20 - 120 nm) with a >55% of L1(0) phase, high coercivity (up to 65 mT) and large saturation magnetization (similar to 140 Am-2/kg) were obtained. The results pave the way for the development of a novel and sustainable route to produce high-anisotropy FeNi nanoparticles of potential interest for next generation critical-element-free permanent magnets

Synthesis of Fe2O3 Nanoparticles and their Catalytic Activity for the Reduction of Halonitroarenes under Sustainable Conditions

Fe2O3 nanoparticles (NPs) with mean size of 50 nm ca. are synthesized starting from a porous organic polymer containing beta-ketoesterate Fe(III) sites (Fe-POP), which is annealed at 400 degrees C under air for 30 min. During calcination, the organic material partially decomposes, and iron(III) oxide NPs onto an organic residue could be observed after annealing. The obtained NPs are characterized by SEM-EDS, IR, and magnetic analyses and they are employed as active catalysts in the reduction of p-bromonitrobenzene into p-bromoaniline, using hydrazine hydrate in ethano

Bacterial Populations Related to Gerbera (Gerbera jamesonii L.) Stem Break

Bacterial distribution, both external (epiphytic) and internal (endophytic), on Gerbera jamesonii L. cv. Provence and its relationship to gerbera stem break and ethylene production were investigated. The greatest number of epiphytic bacteria was found at capitulum level and 20 cm below. Three genera of bacteria were identified: Acinetobacter, Bacillus and Pantoea. A silver-nitrate solution greatly reduced ethylene production in cut flowers. The use of acid fuchsin solution revealed an occlusion of the xylem vessels, probably due to bacterial cells. The bacteria Acinetobacter, Pantoea and Bacillus appeared to be involved in stem break once their populations reached 105 cfu g-1 of stem tissue

Study of microstructure and magnetization reversal mechanism in granular CoCrPt:SiO2 films of variable thickness

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Generation of a localised microwave magnetic field by coherent phonons in a ferromagnetic grating

A high-amplitude microwave magnetic field localized at the nanoscale is a desirable tool for various applications within the rapidly developing field of nanomagnetism. Here, we drive magnetization precession by coherent phonons in a metal ferromagnetic nanograting and generate ac-magnetic induction with extremely high amplitude (up to 10 mT) and nanometer scale localization in the grating grooves. We trigger the magnetization by a laser pulse which excites localized surface acoustic waves. The developed technique has prospective uses in several areas of research and technology, including spatially resolved access to spin states for quantum technologies