Ozone Effects on Botrytis cinerea Conidia using a Bubble Column: Germination Inactivation and Membrane Phospholipids Oxidation

Ozone treatments were applied on conidia aqueous suspensions in order to determine theminimal applied ozone dose to limit conidia germination and to observe the mechanismsinvolved in the spores inactivation. Conidia germination was significantly reduced, bubbling forat least 0.5 min as a gas with a minimal ozone concentration of 1 g.m−3. The applied ozone dosesinduce the membrane phospholipids oxidation, determined by the malondialdehyde quantifica-tion. Membrane phospholipids oxidation and inactivation rate are correlated. So, lipid peroxida-tion and consequently the alteration of the membrane integrity are involved in the antifungalaction of ozone

Characterization of Non-Derivatized Cellulose Samples by Size Exclusion Chromatography in Tetrabutylammonium Fluoride/Dimethylsulfoxide (TBAF/DMSO)

International audienceThis paper deals with the use of tetrabutylammonium fluoride/dimethylsulfoxide (TBAF/DMSO) to characterize the molar mass distribution of non-derivatized cellulosic samples by size exclusion chromatography (SEC). Different cellulose samples with various average degree of polymerization (DP) were first solubilized in this solvent system, with increasing TBAF rates, and then analyzed by SEC coupled to a refractive index detector (RID), using DMSO as mobile phase. The Molar Masses (MM) obtained by conventional calibration were then discussed and compared with suppliers’ data and MM determined by viscosimetry measurements. By this non-classic method, molar mass of low DP samples (Avicel® and cotton fibers) have been determined. For high DP samples (α-cellulose and Vitacel®), dissolution with TBAF concentration of 10 mg/mL involved elution of cellulose aggregates in the exclusion volume, related to an incomplete dissolution or the dilution of TBAF molecules in elution solvent, preventing the correct evaluation of their molar mass

In vitro and in planta fungicide properties of ozonated water against the esca-associated fungus Phaeoacremonium aleophilum

Ozone could be used as a sanitary agent in the food and agricultural industries. The present study investigates whether ozonated water could be used to control conidia dispersal of the esca-associated fungus Phaeoacremonium aleophilum. The fungicide properties of ozonated water was firstly assessed in vitro by exposing spores to several concentrations of ozonated water (2.2, 4.5, or 13.5g/m3 of ozone dissolved into water) and observing the germination rate on plate. Secondarily an in planta approach was conducted on grapevine cuttings of cv. Cabernet Sauvignon clone 15. P. aleophilum conidia were inoculated in pruning wounds, which then received ozonated (4.5g/m3) or sterile water. P. aleophilum DNA was quantified by a quantitative polymerase chain reaction (qPCR) 4 and 9 weeks post-inoculation. The effect of ozonated water on plant-defense gene expression was monitored by reverse-transcriptase qPCR (RT-qPCR) 48h post treatment. The results indicate that ozonated water totally suppresses spore germination in vitro. In addition, at 9 weeks post-inoculation, fungal development was significantly reduced by 50% in planta. RT-qPCR analysis shows that ozonated water did not induce plant-defense-related genes 48h post treatment. The fungicide properties of ozonated water and the absence of gene induction in planta make however ozonated water a promising candidate for limiting grapevine infection by P. aleophilum in nurseries

Multimodal Dispersion of Nanoparticles: A Comprehensive Evaluation of Size Distribution with 9 Size Measurement Methods

Purpose : Evaluation of particle size distribution (PSD) of multimodal dispersion of nanoparticles is a difficult task due to inherent limitations of size measurement methods. The present work reports the evaluation of PSD of a dispersion of poly(isobutylcyanoacrylate) nanoparticles decorated with dextran known as multimodal and developed as nanomedecine. Methods : The nine methods used were classified as batch particle i.e. Static Light Scattering (SLS) and Dynamic Light Scattering (DLS), single particle i.e. Electron Microscopy (EM), Atomic Force Microscopy (AFM), Tunable Resistive Pulse Sensing (TRPS) and Nanoparticle Tracking Analysis (NTA) and separative particle i.e. Asymmetrical Flow Field- Flow Fractionation coupled with DLS (AsFlFFF) size measurement methods. Results : The multimodal dispersion was identified using AFM, TRPS and NTA and results were consistent with those provided with the method based on a separation step prior to on-line size measurements. None of the light scattering batch methods could reveal the complexity of the PSD of the dispersion. Conclusions : Difference between PSD obtained from all size measurement methods tested suggested that study of the PSD of multimodal dispersion required to analyze samples by at least one of the single size particle measurement method or a method that uses a separation step prior PSD measurement

Influence of Storage Temperature on the Composition and the Antibacterial Activity of Ozonized Sunflower Oil

The use of ozonized vegetable oils as drugs or cosmetics requires having data on their stability over the time. In this study, ozonized sunflower oil was stored under different temperatures for up to 1 year. Peroxide index, acidity value, gas chromatography profile, infrared profile and antibacterial activity (against Streptococcus uberis) of this ozonized oil were followed. The results highlight the fact that the better way to preserve the initial composition of ozonized oil is to keep it at low temperature. However, the antibacterial activity is not diminished by the changes occurring to the composition

Kinetics of heat-induced denaturation of whey proteins and characterization of protein aggregates in model infant formulas

In 2018, about 60% of world’s newborns received cow milk-based infant formulas (IF) instead of human milk (UNICEF). The process of manufacturing IF involves heat treatments altering the physicochemical properties of milk components, especially whey proteins (WP), and so the rheological properties of IF. The objective of the study was to investigate the impacts of thermal treatments on the denaturation of WP of IF, particularly for those mimicking the protein profile of human milk, and to characterize the heat-induced protein structures.Three model IF were produced with a caseins:WP ratio of 40:60 at 1.3% and 5.5% of total proteins, i.e. the protein contents at which are applied heat treatments during the manufacture of liquid or powder IF, respectively. Skimmed milk was mixed with a WP isolate, a mix of WP isolate and purified lactoferrin or a mix of both purified lactoferrin and α-lactalbumin in proportion similar to that in human milk. The kinetic of heat-induced denaturation of each WP was investigated between 67.5°C and 80°C by RP-HPLC. The heat-induced protein structures were studied by dynamic light scattering, electrophoresis and asymmetric flow field flow fractionation coupled with MALLS.The results revealed that the extent of denaturation of WP depended on the protein content and the nature of the WP within the IF. IF at 5.5% of proteins and containing β-lactoglobulin gelled for longer heating time at 80°C. At similar rate of total WP denaturation at 67.5°C and 80°C, the protein composition of the heat-induced aggregates changed between formulas, protein concentrations and heating temperatures but disulfide bonds were the main intermolecular links. The aggregates were larger and of fractal shape (dfapp=2.1) in formulas at 5.5% proteins whereas they were of spherical shape (dfapp=2.9) in formulas at 1.3% proteins.These results will give to industrials reliable data on the protein structures formed during the heat treatments of IF. The impact on digestibility will be subsequently investigated

Crosslinked polymeric self-assemblies as an efficient strategy for photodynamic therapy on a 3D cell culture

In order to compare the efficiency of crosslinked nano-vectors in the field of photodynamic therapy (PDT) both on 2D and 3D cell cultures, various polymeric crosslinked self-assemblies based on poly(ethyleneoxide-b-ε-caprolactone) have been synthesized by radical polymerization of acrylate end-functionalized polymers. Crosslinked self-assemblies obtained from the reaction of the functionalized polymers with ethyleneglycoldimethacrylate (EGDMA) were compared to chain-end polymerized and to unreacted ones. Polymeric micelles with a size between 10 and 20 nm were obtained, as well as an elongated system with a length close to 100 nm. They all have been characterized by Transmission Electron Microscopy and Dynamic Light Scattering but also by Asymmetrical Flow Field-Flow Fractionation in order to prove that they consisted of pure self-assemblies. Chain-end polymerization or crosslinking did not induce any change in morphology nor strong size modification. After post-encapsulation of a photosensitizer, namely Pheophorbide a, the systems have been examined for their potential use in PDT on HCT-116 and FaDu human tumor cell lines both in 2D and 3D cultures. The crosslinked vectors were observed to be the most efficient on both cell lines cultivated in 3D spheroids, whereas unreacted or chain-end polymerized ones presented a lower activity. This was different from the trend observed in 2D cell cultures where an uncrosslinked micelle was observed to be efficient at a lower concentration compared to its chain-end polymerized or crosslinked analogue. The different synthesized self-assemblies also allowed assessing the influence of polymer chain length and shape on PDT efficiency. The molecular weight of the polymer did not lead in our case to efficiency change, for similar size and surface characteristics. As for the shape effect, the elongated self-assembly was not observed in our case to be more efficient than spherical micelles. Crosslinked polymeric vectors are therefore promising vectors for 3D tumor treatment

The effect of vegetable protein modifications on the microencapsulation process

The use of soy proteins (SoyP) and sunflower proteins (SunP) in the microencapsulation by spray-drying technique of α-tocopherol (T) with a core/wall ratio of 2/1 was studied. SoyP and SunP were used as wall material in an unmodified and modified state. The enzymatic (hydrolysis and cross-linking) and chemical (acylation and cationization) modifications were carried out on vegetable proteins in order to improve their encapsulating properties. The results obtained demonstrated that in the native state, SunP showed higher retention efficiency for T microencapsulation (92.6%) compared to SoyP (79.7%), which could be connected to the different composition of protein extracts. Hydrolysis, acylation and cationization of protein resulted in reduced emulsion viscosity. The retention efficiency of T was improved up to 94.8–99.5% after protein acylation, which was attributed to improved affinity between core and wall material

Self-assembled polymeric vectors mixtures: characterization of the polymorphism and existence of synergistic effects in photodynamic therapy

The objective of this work was to assess the relation between the purity of polymeric self-assemblies vectors solution and their photodynamic therapeutic efficiency. For this, several amphiphilic block copolymers of poly(ethyleneoxide-b-ε-caprolactone) have been used to form self-assemblies with different morphologies (micelles, worm-like micelles or vesicles). In a first step, controlled mixtures of preformed micelles and vesicles have been characterized both by dynamic light scattering and asymmetrical flow field flow fractionation (AsFlFFF). For this, a custom-made program, STORMS, was developed to analyze DLS data in a thorough manner by providing a large set of fitting parameters. This showed that DLS only sensed the larger vesicles when the micelles/vesicles ratio was 80/20 w/w. On the other hand, AsFlFFF allowed clear detection of the presence of micelles when this same ratio was as low as 10/90. Subsequently, the photodynamic therapy efficiency of various controlled mixtures was assessed using multicellular spheroids when a photosensitizer, pheophorbide a, was encapsulated in the polymer self-assemblies. Some mixtures were shown to be as efficient as monomorphous systems. In some cases, mixtures were found to exhibit a higher PDT efficiency compared to the individual nano-objects, revealing a synergistic effect for the efficient delivery of the photosensitizer. Polymorphous vectors can therefore be superior in therapeutic applications

Procédé de préparation d'un matériau solide de stockage de l'ozone, ledit matériau et ses utilisations

La présente invention concerne un procédé et une installation pour la préparation d’un matériau solide de stockage de l’ozone, ce procédé comprenant la mise en contact de cyclodextrines et/ou de dérivés de cyclodextrines se présentant sous forme solide avec un gaz comprenant de l’ozone moyennant quoi un matériau solide de stockage de l’ozone est obtenu. La présente invention concerne également le matériau ainsi préparé et ses utilisations