A Lignin-Rich Extract of Giant Reed (Arundo donax L.) as a Possible Tool to Manage Soilborne Pathogens in Horticulture: A Preliminary Study on a Model Pathosystem

Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic requirements. Some studies have already highlighted antimicrobial and antifungal properties of giant reed-derived compounds. This study aimed at investigating the potential of a lignin-rich giant reed extract for crop protection. The extract, obtained by dry biomass treatment with potassium hydroxide at 120◦C, followed by neutralization, was chemically characterized. A preliminary in vitro screening among several pathogenic strains of fungi and oomycetes showed a high sensitivity by most of the soilborne pathogens to the extract; thus, an experiment was performed with the model pathosystem, Pythium ultimum–zucchini in a growth substrate composed of peat or sand. The adsorption by peat and sand of most of the lignin-derived compounds contained in the extract was also observed. The extract proved to be effective in restoring the number of healthy zucchini plantlets in the substrate infected with P. ultimum compared to the untreated control. This study highlights the potential of the lignin-rich giant reed extract to sustain crop health in horticulture

Effects of Au nanoparticles on photoluminescence emission from Si-vacancy in diamond

We studied the coupling of diamond Si color centers with size-controlled Au nanoparticles obtained by chemical routes. The diamond samples, synthesized by Chemical Vapor Deposition, were polycrystalline films or isolated grains. The plasmonic responses of the Au nanoparticles were found to couple with the Ar+ laser frequency or with the frequency of the Si-defects photoluminescence (PL). When the PL of Si optical centers is resonant with the maximum of the Au extinction spectrum, a threshold behavior and a decrease of the PL band FWHM with increasing laser energy is detected, suggesting the transition from spontaneous to stimulated emission

Gold nanoparticles on nanodiamond for nanophotonic applications

We present here some recent results of a research focused on the prepn. of detonation nanodiamond/Au nanoparticles hybrid materials. Two different exptl. routes are followed for the decoration of diamond nanoparticles by Au nanoparticles, that are in turn prepd. by an innovative electroless approach. Structure and morphol. at the nanoscale level of the Au-on-nanodiamond deposits have been deeply investigated by electron microscopy (FE-SEM, HR-TEM) and diffraction (XRD) techniques. Optical properties of these systems have been detd. by performing scattering and UV-Vis absorption measurements, and by comparing the exptl. data with simulated extinction spectra. The results highlighted very interesting plasmonic and scattering behaviors, mainly related to the high refractive index of diamond

CVD-based techniques for the synthesis of nanographites and nanodiamonds

We report about some Chemical Vapor Deposition approaches used to produce a variety of C-sp2 and C-sp3 crystalline nanostructures. The methodologies developed in our laboratories provide custom-made solutions for the fabrication of specific carbon nanomaterials with properties tailored for applications in the field of nanotechnology

Jania adhaerens Primes Tomato Seed against Soil-Borne Pathogens

Managing soil-borne pathogens is complex due to the restriction of the most effective synthetic fungicides for soil treatment. In this study, we showed that seed priming with Jania adhaerens water-soluble polysaccharides (JA WSPs) was successful in protecting tomato plants from the soil-borne pathogens Rhizoctonia solani, Pythium ultimum, and Fusarium oxysporum under greenhouse conditions. WSPs were extracted from dry thallus by autoclave-assisted method, and the main functional groups were characterized by using FT-IR spectroscopy. WSPs were applied by seed treatment at 0.3, 0.6 and 1.2 mg/mL doses, and each pathogen was inoculated singly in a growing substrate before seeding/transplant. Overall, WSPs increased seedling emergence, reduced disease severity and increased plant development depending on the dose. Transcriptional expression of genes related to phenylpropanoid, chlorogenic acid, SAR and ISR pathways, and chitinase and beta-1,3 glucanase activities were investigated. Among the studied genes, HQT, HCT, and PR1 were significantly upregulated depending on the dose, while all doses increased PAL and PR2 expression as well as beta-1,3 glucanase activity. These results demonstrated that, besides their plant growth promotion activity, JA WSPs may play a protective role in triggering plant defense responses potentially correlated to disease control against soil-borne pathogens

One-step growth and shaping by a dual plasma reactor of diamond nanocones arrays for the assembling of stable cold cathodes

Arrays of conical-shaped nanodiamond structures are formed on silicon substrate by a single-step CVD process from CH4/H-2 mixtures. The formation of these nanocones has been found to depend on interplay between growing and etching during the CVD process carried out in a dual-mode MW/RF plasma reactor. Morphology and structure of the conical-like systems can be controlled by varying the process parameters, and have been investigated by scanning electron microscopy (SEM), reflection high energy electron diffraction (RHEED) and micro-Raman spectroscopy. The Field Emission (FE) properties of different diamond nanocones arrays have been investigated and compared with those of analogous systems in order to assess the feasibility of the present nano-materials as electron emitters for cold cathodes. The FE behavior is discussed taking into account the structure of the different diamond nanocones

Hybrid Cnanotubes/Si 3D nanostructures by one-step growth in a dual-plasma reactor

Hybrid nanostructures consisting of Si polycrystalline nanocones, with an anemone-like termination coated with C-nanotubes bundles, have been generated on a (1 0 0) Si substrate in a dual mode microwave/radio-frequency plasma reactor. The substrate is both heated and bombarded by energetic H ions during the synthesis process. The nanocones growth is explained considering pull of the growing Si nanocrystalline phase along the lines of the electrical field, likely via a molten/recrystallization mechanism. The one-step building of the achieved complex 3D architectures is described in terms of dynamic competition between Si and C nanotubes growth under the peculiar conditions of kinetically driven processes

CVD-based techniques for the synthesis of nanographites and nanodiamonds

We report about some Chemical Vapor Deposition approaches used to produce a variety of C-sp2 and C-sp3 crystalline nanostructures. The methodologies developed in our laboratories provide custom-made solutions for the fabrication of specific carbon nanomaterials with properties tailored for applications in the field of nanotechnology

A Yellow Fluorescent Protein variant as an intracellular iodide biosensor in thyroid cells

Book Description: A biosensor is an analytical device which converts a biological response into an electrical signal. It consists of 3 parts: the sensitive biological element, the transducer and the associated electronics or signal processors that are primarily responsible for the display of the results in a user-friendly way. The most widespread example of a commercial biosensor is the blood glucose biosensor. Recently, arrays of many different detector molecules have been applied in so-called electronic nose devices, where the pattern of response from the detectors is used to fingerprint a substance. There are also several applications of biosensors in food analysis. Optical sensors are used to detect pathogens and food toxins. Thus, the light system in these biosensors has been fluorescence, since this type of optical measurement can greatly amplify the signal. This book will present research on new materials, technologies as well as applications in the field of biosensors

Fluorescence quantitation of thyrocyte iodide accumulation with the yellow fluorescent protein variant YFP-H148Q/I152L

The thyroid gland accumulates iodide for the synthesis of thyroid hormones. The aim of the current study was to quantify iodide accumulation in cultured thyroid cells by live cell imaging using the halide-sensitive yellow fluorescent protein (YFP) variant YFP-H148Q/I152L. In vivo calibrations were performed in FRTL-5 thyrocytes to determine the sensitivity of YFP-H148Q/I152L to iodide. In the presence of ion-selective ionophores, YFP-H148Q/I152L fluorescence was suppressed by halides in a pH-dependent manner with 20-fold selectivity for iodide versus chloride and competition between the two halides. At a physiological pH of 7 and a chloride concentration of 15mM, the affinity constant of YFP-H148Q/I152L for iodide was 3.5mM. In intact FRTL-5 cells, iodide induced a reversible decrease in YFP-H148Q/I152L fluorescence. FRTL-5 cells concentrated iodide to 60 times the extracellular concentration. Iodide influx exhibited saturation kinetics with respect to extracellular iodide with a K(m) of 35muM and a V(max) of 55muM/s. Iodide efflux exhibited saturation kinetics with respect to intracellular iodide concentration with a K(m) of 2.2mM and a V(max) of 43muM/s. The results of this study demonstrate the utility of YFP-H148Q/I152L as a sensitive and selective biosensor for the quantification of iodide accumulation in thyroid cells