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International audience; One way of exploring knowledge representation is to compare expert and non-expert strategies. Expert knowledge representation seems to be acquired through both exposure and intensive formal training, leading to the development of skills and conceptual knowledge related to a specific field. The objective of our study was to dissociate the effects of familiarity and expertise on the development of knowledge representations about wine. Three panels were therefore recruited to study the conceptual representations of Beaujolais red wines among wine,experts and consumers. One panel was composed of unfamiliar consumers from a region without wine production, while the other two were familiar consumers, or experts, both from the Beaujolais region. A free hierarchical sorting task with wine labels was followed by a semi-directed interview. The results of the hierarchical sorting task showed that the three panels formed common groups that were mostly related to the Beaujolais wine taxonomy-based system. However, the interview results regarding criteria and strategies showed that the three panels had very different knowledge representations of Beaujolais wines. Although experts and familiar consumers used top-down strategies based on knowledge, their wine knowledge representations differ. For experts, knowledge representation is flexible and leads to different categorization schemes, while for familiar consumers, knowledge representation is rigid and leads to a single categorization scheme based on the Beaujolais taxonomy. Unfamiliar consumers have fragmented knowledge, leading to the use of bottom-up strategies to compensate for their lack of exposure to wine. This strategy leads to a misrepresentation of Beaujolais wines.

International audience; Two kitchen garden soils (A and B) sampled in contaminated areas were amended using phosphates in sustainable quantities in order to reduce the environmental availability of potentially toxic inorganic elements (PTEs) and to favour the availability of alkali, alkali earth and micronutrients. The environmental availability of PTEs was evaluated using a potential plant for revegetation of contaminated soils (ryegrass) and a mixture of low molecular weight organic acids. Despite the highest contamination level of B, the concentration of metals was highest in the ryegrass shoots grown on A for the two harvests. These results correlated well with those obtained using low molecular weight organic acids for Cd, Zn and Cu, whereas this mixture failed to represent the transfer of nutrients due to the presence of biological and physiological mechanisms. The statistical differences between the biomass of ryegrass obtained at the first and the second harvests were attributed to the decrease of available potassium, implicated in the growth and development of plants. Phosphates increased the ratios Zn/Cd, Zn/Pb and Zn/Cu up to 176 ± 48, 38 ± 6 and 80 ± 12, respectively, and made possible the reduction of the concentration of Cd and Pb in the shoots of ryegrass by 22% and 25%, respectively. The concentration of Zn in the shoots of ryegrass from the first and the second harvests grown on soil A were in the range 1050–2000 mg kg−1, making this plant a potential biomass to (i) produce biosourced catalysts for organic chemistry applications in a circular economy concept and (ii) limit human exposure to commercial Lewis acids. A preliminary application was identified. © 2019, Springer Nature Switzerland AG.

Feces from 142 animals were collected on 15 farms in the region of Brittany, France. Each sample was directly collected from the rectum of the animal and identified with the ear tag number. Animals were sampled three times, at 5, 15 and 22 weeks of age. After DNA extraction from stool samples, nested PCR was performed to amplify partial 18S-rDNA and 60 kDa glycoprotein genes of Cryptosporidium. The parasite was detected on all farms. One hundred out of 142 calves (70.4%) were found to be parasitized by Cryptosporidium. Amplified fragments were sequenced for Cryptosporidium species identification and revealed the presence of C. parvum (43.8%), C. ryanae (28.5%), and C. bovis (27%). One animal was infected with Cryptosporidium ubiquitum. The prevalence of these species was related to the age of the animal. C. parvum caused 86.7% of Cryptosporidium infections in 5-week-old calves but only 1.7% in 15-week-old animals. The analysis of the results showed that animals could be infected successively by C. parvum, C. ryanae, and C. bovis for the study period. C. parvum gp60 genotyping identifies 6 IIa subtypes of which 74.5% were represented by IIaA15G2R1. This work confirms previous studies in other countries showing that zoonotic C. parvum is the dominant species seen in young calves.

International audience; Fusarium head blight (FHB) is a cereal disease of major importance responsible for yield losses and mycotoxin contaminations in grains. Here, we introduce a new measurement approach to quantify FHB severity on grains based on the evaluation of the whitened kernel surface (WKS) using digital image analysis. The applicability of WKS was assessed on two bread wheat and one triticale grain sample sets (265 samples). Pearson correlation coefficients between Fusarium-damaged kernels (FDK) and WKS range from r = 0.77 to r = 0.81 and from r = 0.61 to r = 0.86 for the correlation between deoxynivalenol (DON) content and WKS. This new scoring method facilitates fast and reliable assessment of the resistance to kernel infection and shows significant correlation with mycotoxin content. WKS can be automated and does not suffer from the "human factor" inherent to visual scorings. As a low-cost and fast approach, this method appears particularly attractive for breeding and genetic analysis of FHB resistance where typically large numbers of experimental lines need to be evaluated, and for which WKS is suggested as an alternative to visual FDK scorings.

Particle-based photodynamic therapy (PPDT) holds great promise in theranostic applications. Herein, we demonstrate that PPDT based on gold nanorods coated with an indocyanine green (ICG)-loaded silica shell allows for the inactivation of the Crohn's disease-associated adherent-invasive Escherichia coli strain LF82 (E. coli LF82) under pulsed laser light irradiation at 810 nm. Fine-tuning of the plasmonic structures together with maximizing the photosensitizer loading onto the nanostructures allowed optimizing the singlet oxygen generation capability and the PPDT efficiency. Using a nanoparticle concentration low enough to suppress photothermal heating effects, 6 log10 reduction in E. coli LF82 viability could be achieved using gold nanostructures displaying a plasmonic band at 900 nm. An additional modality of nanoparticle-based photoinactivation of E. coli is partly observed, with 3 log10 reduction of bacterial viability using Au NRs@SiO2 without ICG, due to the two-photon induced formation of reactive oxygen species. Interaction of the particles with the bacterial surface, responsible for the disruption of the bacterial integrity, together with the generation of moderate quantities of singlet oxygen could account for this behavior.

International audience; Blood, from slaughterhouses, is an inevitable part of meat production, causing environmental problems due to the large volumes recovered and its low valorization. However, the α137-141 peptide, a natural antimicrobial peptide, can be obtained after hydrolysis of hemoglobin, the main constituent of blood red part. To recover it at a sufficient concentration for antimicrobial applications, a new sustainable technology, called electrodialysis with ultrafiltration membrane (EDUF), was investigated. The α137-141 concentration was increased about 4-fold at a feed peptide concentration of 8% with an enrichment factor above 24-fold. This feed peptide concentration also needed the lowest relative energy consumption. Moreover, this peptide fraction protected meat against microbial growth, as well as rancidity, during 14 days under refrigeration. This peptide fraction was validated as a natural preservative and substitute for synthetic additives against food spoilage. Finally, producing antimicrobial/antioxidant peptide from wastes by EDUF fits perfectly with the concept of circular economy.

International audience; This study presents a miniaturized 3-methyl-2-benzothiazolinone hydrazone hydrochloride-assay (MBTHassay) 1 , optimized for high-throughput measurement of shrimp phenol oxidase activities and the screening of potential inhibitors of post-mortem melanosis. To validate this approach, assay parameters, including limit of detection and dynamic range, were compared to values obtained for DOPAchrome-assay, used here as a reference method. A reliable high-throughput automatized analysis was also performed, under standardized parameters, in order to compare and characterize 40 potential inhibitors of phenol oxidase activities. Among the selected molecules, twenty showed inhibitory action. Enzyme-inhibitor dissociation constant (K i), median inhibitor concentration (IC 50) and inhibition modes could be determined for nine of them. 4-Hexylresorcinol, Nphenylthiourea L-cystein and glutathione displayed K i values lower than sulfite salts (Na 2 S 2 O 5 and Na 2 SO 3) used as positive controls.

International audience; The objectives of this work are to address the prebiotic effects of chicory (Cichorium intybus) together with its possible role in appetite control. We compared nine chicory genotypes in order to determine if variations in the content of metabolites in the roasted roots would lead to modifications in release of satiety hormones and in composition of gut microbiota. To this aim, a 5-week dietary-intervention study was achieved using mice fed with distinct chicory-based preparations. A 16S rRNA gene-based metagenetic analysis of fecal microbiota was performed. In vitro gastrointestinal digestions were performed in order to study the effect of chicory intestinal digests on gut hormone regulation in enteroendocrine cells. Firmicutes/ Bacteroidetes ratio and gut bacterial groups, such as Alloprevotella, Blautia, Alistipes, and Oscillibacter, were found to be modulated by chicory. On the other hand, CCK and GLP-1 satiety hormones were demonstrated to be significantly increased by chicory in vitro.

The objective of the present study was to reproduce in 4 months the quality changes that occur in shelf-stable strawberry pudding after 1 year of storage. A full factorial experiment 23 was used to investigate the effect of storage temperature (16 and 30 °C), headspace volume (9.5 and 18 cm3), and agitation (no/yes—pouches turned upside down twice a week) on aging. Sensory, rheological, pH, and fluorescence measurements were performed on samples subjected to accelerated aging tests (up to 4 months) or stored in standard conditions (up to 1 year). Although storage at 30 °C induced a slight decrease in apparent viscosity and thickness—in contrast with samples stored at 16 °C—it showed the best results for most of the studied parameters, regardless of the headspace volume and agitation. Hence, storage at 30 °C could be used for accelerated shelf-life or stability studies of sterilized pudding.

International audience; The Arabidopsis thaliana genome contains 58 members of the solute carrier family SLC25, also called the mitochondrial carrier family, many of which have been shown to transport specific metabolites, nucleotides, and cofactors across the mitochondrial membrane. Here, two Arabidopsis members of this family, AtUCP1 and AtUCP2, which were previously thought to be uncoupling proteins and hence named UCP1/PUMP1 and UCP2/PUMP2, respectively, are assigned with a novel function. They were expressed in bacteria, purified, and reconstituted in phospholipid vesicles. Their transport properties demonstrate that they transport amino acids (aspartate, glutamate, cysteine sulfinate, and cysteate), dicarboxylates (malate, oxaloacetate, and 2-oxoglutarate), phosphate, sulfate, and thiosulfate. Transport was saturable and inhibited by mercurials and other mitochondrial carrier inhibitors to various degrees. AtUCP1 and AtUCP2 catalyzed a fast counterexchange transport as well as a low uniport of substrates, with transport rates of AtUCP1 being much higher than those of AtUCP2 in both cases. The aspartate/glutamate heteroexchange mediated by AtUCP1 and AtUCP2 is electroneutral, in contrast to that mediated by the mammalian mitochondrial aspartate glutamate carrier. Furthermore, both carriers were found to be targeted to mitochondria. Metabolite profiling of single and double knockouts shows changes in organic acid and amino acid levels. Notably, AtUCP1 and AtUCP2 are the first reported mitochondrial carriers in Arabidopsis to transport aspartate and glutamate. It is proposed that the primary function of AtUCP1 and AtUCP2 is to catalyze an aspartate(out)/glutamate(in) exchange across the mitochondrial membrane and thereby contribute to the export of reducing equivalents from the mitochondria in photorespiration.

International audience; For powder catalyst characterization, Fourier Transform Infrared (FTIR), Raman, and X-Ray Fluorescence (XRF) spectrometers and X-Ray Diffraction (XRD) are available in high-throughput (HT) configurations, for example at the REALCAT platform to sequentially analyse multiple sets of samples. To remove the bottleneck resulting from the use of different sample holders for each equipment, a unique multi-well plate was developed. This paper details the design of such a plate including the selection of the fabrication material and the plate dimensioning based on the study of the 4 different physical interactions between matter and electromagnetic radiations for the aforementioned techniques. This new plate consists of a holder for removable wells enabling the avoidance of cross-contamination between samples. Raman, a focusing technique, has no strict constraint on the plate design. The number of wells, their geometry, spacing and dimensions were adjusted to deal with the constraints of IR optics. The well depth was set according to the XRF maximum penetration depth in the sample. The well diameter was optimized in order to obtain from the X-ray spot size the maximum achievable intensity. Poly-methyl-methacrylate (PMMA) was chosen as the material for the new plate due to its amorphous structure (no peak in XRD analysis) and ease with which it can be cut by a laser. Finally, the flatness of the multi-well plate was validated on the most challenging instrument: XRD. This new plate allows fast sample filling/preparation, requires small quantities of catalyst (50 to 80 mg) in each well and is compatible and convenient for HT experimentation.

International audience; The aim of this study was to evaluate the potential of using front face fluorescence spectroscopy (FFFS) to discriminate fresh refrigerated (up to 13 days at 4 °C) sea bass (Dicentrarchus labrax) fillets (F group) from: i) frozen-thawed (3 months at −18 °C), then refrigerated up to 9 days fillets at 4 °C (F-T R group), and ii) refrigerated (up to 9 days at 4 °C), then frozen-thawed (3 months at −18 °C) fillets (R F-T group). The evolution of emission fluorescence spectra after excitation set at 290, 340, and 380 nm, and excitation spectra after emission set at 410 nm were acquired throughout storage. Some traditional measurements based on color, textural, and chemical parameters were performed on the same fillets. Canonical correlation analysis (CCA), applied to the traditional and fluorescence data sets, showed high correlations between the two data sets, since squared canonical coefficients were found higher than 0.8 for canonical variates 1 and 2. This was confirmed by the factorial discriminant analysis (FDA) applied to the concatenated emission spectra recorded after excitation sets at 340 and 380 nm since 72 out of 78 samples were correctly classified. Finally, a multi-block analysis method based on common components and specific weights analysis (CCSWA) was applied to the whole data sets. A reliable discrimination between fresh from frozen/thawed fish was found suggesting that FFFS could be used as a promising tool in routine inspection for differentiating between fresh and frozen-thawed fish.

International audience; The potentiality of the front-face fluorescence spectroscopy coupled with chemometric tools to characterize changes in camel milk following thermal treatments in the 55–75 °C temperature range from 0.5 min up to 30 min was studied. Nicotinamide adenine dinucleotide (NADH), fluorescent Maillard reaction products (FMRP) and vitamin A fluorescence spectra were collected on camel milk samples. Using principal component analysis (PCA), the vitamin A spectra allowed some discrimination between milk samples according to heat treatment intensity and holding time. The best results was obtained by applying common components and specific weights analysis (CCSWA) to the three spectral data sets, since a clear differentiation between camel milk samples preheated at 70 and 75 °C from the others was achieved. Apparent activation energy of camel milk determined from NADH, FMRP and vitamin A spectra was of 85.1, 84.2 and 47.3 kJ mol−1, respectively. The spectral patterns of the CCSWA model enabled us to get information about the molecular changes occurring in camel milk fluorophores during heat treatment.

National audience; Zymoseptoria tritici, responsible for Septoria tritici blotch, is the most important pathogen of wheat. The control of this parasite relies mainly on synthetic fungicides, but their use is increasingly controversial and searching for alternative management strategies is encouraged. In this context, the biocontrol potential of crude methanolic extracts of eight extremophile plant species from Tunisia, including three xerophytes and five halophytes, against Z. tritici was assessed. Only the extract of Juncus maritimus rhizomes showed significant in vitro antifungal activity. In extremophile plants, the production of secondary metabolites is often influenced by abiotic conditions. Thus, we collected several samples of J. maritimus rhizomes at different vegetative stages, at different periods, and from different substrates to compare their antifungal activities. Our results suggest that the plant environment, especially the substrate of the soil, should be taken into account to identify great sources of natural antifungal products. From the most active sample, a 9,10-dehydrophenanthrene derivative, effusol, absent from other J. maritimus rhizomes extracts, was purified. This product showed a strong antifungal activity against the pathogen, with a minimal inhibitory concentration of 19gmL(-1) and an half-maximal inhibitory concentration of 9.98gmL(-1). This phenanthrene derivative could be a promising biocontrol molecule against Z. tritici.

The objective of this work was to examine the effectiveness of adsorption for the removal of polyphenols from an alfalfa white protein concentrate to produce a protein purified fraction. Six commercial macroporous resins were tested for their polyphenols adsorption characteristics. The screening results showed that the adsorbent HP20 and the anion-exchange resin AER1 had the best adsorption characteristics with adsorption capacities of 54.62 mg/g and 48.18 mg/g, respectively. The effect of pH, contact time and adsorption isotherms were successively investigated on the two preselected resins. The process kinetics was evaluated by the pseudo-first-order, the pseudo-second-order, Elovich, intra-particle diffusion and the modified pseudo-first-order models. Batch kinetic data have been well described by the pseudo second order model. Meantime, the adsorption process close equilibrium was governed by intra-particle diffusion. The adsorption data were fitted well with the Langmuir isotherm model. It was found that the process is favourable. These results will be used in future studies for the design of column adsorption systems for the purification of the alfalfa protein concentrate and the recovery of phenolic compounds contained in the latter.

The objective of the present study was to evaluate the impact of rosemary and basil essential oils (EOs) onthe quality of Atlantic mackerel fillets stored at 2°C up to 15 days. Atlantic mackerel (Scomber scombrus) fillets were periodically evaluated to assess their textural, color, physicochemical, andspectral characteristics. The results indicated that rosemary and basil treatments were effective for inhibiting the formation of total volatile basic nitrogen (TVB-N) and lipid oxidation products during storage. Based on TVB-N values, the shelf life of Atlantic mackerel fillets treated with rosemary and basil EOs was extended by 2 and 5 days, respectively, compared to the control group. Similar results were obtained with thiobarbituricacid–reactive substance analysis, which demonstrated an extended shelf life of Atlantic mackerel immersed with rosemary and basil EOs of 2 and 3 days, respectively, compared to the control group. The factorial discriminant analysis applied on the concatenated first five principal components corresponding to the physicochemical, textural, color, and fluorescence measurements allowed clear discrimination of the three groups, because a correct classification rate of 93.3% was obtained. Therefore, treatment with basil and rosemary EOs, as natural biopreservative compounds, could present a high-potential application in the seafood industry.

International audience; The current methods used to routinely assess freshness in the fishing industry reflect more a state of spoilage than a state of freshness. Mitochondria, the seat of cellular respiration, undergo profound changes in post mortem tissues. The objective of this study was to demonstrate that mitochondrial activity constitutes a putative early fish freshness marker. The structure of gilthead sea bream (Sparus aurata) muscle tissue was evaluated over time by transmission electron microscopy. Respiration was assessed in mitochondria isolated from sea bream fillets using oxygraphy. Membrane potential (Delta Psi(m)) was determined by fluorescence (Rhodamine 123). Mitochondrial activity of fillets stored at + 4 degrees C was studied for 6 days. Changes in mitochondrial cristae structure appeared from Day 3 highlighting the presence of dense granules Delta Psi(m) and mitochondrial activity were significantly disrupted in sea bream fillets after 96 h of storage at + 4 degrees C. Mitochondrial activity constituted a reliable and early indicator of fish freshness.

We wish to predict changes of reaction networks with partial kinetic information that lead to target changes of their steady states. The changes may be either increases or decreases of influxes, reaction knockouts, or multiple changes of these two kinds. Our prime applications are knockout prediction tasks for metabolic and regulation networks. In a first step, we propose a formal modeling language for reaction networks with partial kinetic information. The modeling language has a graphical syntax reminiscent to Petri nets. Each reaction in a model comes with a partial description of its kinetics, based on a similarity relation on kinetic functions that we introduce. Such partial descriptions are able to model the regulation of existing metabolic networks for which precise kinetic knowledge is usually not available. In a second step, we develop prediction algorithms that can be applied to any reaction network modeled in our language. These algorithms perform qualitative reasoning based on abstract interpretation, by which the kinetic unknowns are abstracted away. Given a reaction network, abstract interpretation produces a finite domain constraint in a novel class. We show how to solve these finite domain constraints with an existing finite domain constraint solver, and how to interpret the solution sets as predictions of multiple reaction knockouts that lead to a desired change of the steady states. We have implemented the prediction algorithm and integrated it into a prediction tool. This journal article extends the two conference papers John et al. (2013) and Niehren et al. (2015) while adding a new prediction algorithm for multiple gene knockouts. An application to single gene knockout prediction for surfactin overproduction was presented in Coutte et al. (2015). It illustrates the adequacy of the model-based predictions made by our algorithm in the wet lab.

International audience; Sudden unexpected death in infancy occurs in apparently healthy infants and remains largely unexplained despite thorough investigation. The vast majority of cases are sporadic. Here we report seven individuals from three families affected by sudden and unexpected cardiac arrest between 4 and 20 months of age. Whole-exome sequencing revealed compound heterozygous missense mutations in PPA2 in affected infants of each family. PPA2 encodes the mitochondrial pyrophosphatase, which hydrolyzes inorganic pyrophosphate into two phosphates. This is an essential activity for many biosynthetic reactions and for energy metabolism of the cell. We show that deletion of the orthologous gene in yeast (ppa2Δ) compromises cell viability due to the loss of mitochondria. Expression of wild-type human PPA2, but not PPA2 containing the mutations identified in affected individuals, preserves mitochondrial function in ppa2Δ yeast. Using a regulatable (doxycycline-repressible) gene expression system, we found that the pathogenic PPA2 mutations rapidly inactivate the mitochondrial energy transducing system and prevent the maintenance of a sufficient electrical potential across the inner membrane, which explains the subsequent disappearance of mitochondria from the mutant yeast cells. Altogether these data demonstrate that PPA2 is an essential gene in yeast and that biallelic mutations in PPA2 cause a mitochondrial disease leading to sudden cardiac arrest in infants.

International audience; The steady increase in antimicrobial resistance in different 16 pathogens requires the development of alternative treatment strategies 17 next to the oral delivery of antibiotics. A photothermally activated 18 platform based on reduced graphene oxide (rGO)-embedded polymeric 19 nanofiber mats for on-demand release of antibiotics upon irradiation in 20 the near-infrared is fabricated. Cross-linked hydrophilic nanofibers, 21 obtained by electrospinning a mixture of poly(acrylic acid) (PAA) and 22 rGO, show excellent stability in aqueous media. Importantly, these PAA@ 23 rGO nanofiber mats exhibit controlled photothermal heating upon 24 irradiation at 980 nm. Nanofiber mats are efficiently loaded with 25 antibiotics through simple immersion into corresponding antibiotics 26 solutions. Whereas passive diffusion based release at room temperature is 27 extremely low, photothermal activation results in increased release within 28 few minutes, with release rates tunable through power density of the 29 applied irradiation. The large difference over passive and active release, as well as the controlled turn-on of release allows 30 regulation of the dosage of the antibiotics, as evidenced by the inhibition of planktonic bacteria growth. Treatment of superficial 31 skin infections with the antibiotic-loaded nanofiber mats show efficient wound healing of the infected site. Facile fabrication and 32 implementation of these photothermally active nanofiber mats makes this novel platform adaptable for on-demand delivery of 33 various therapeutic agents. 34

International audience; Septoria tritici blotch (STB) caused by the heterothallic ascomycete Zymoseptoria tritici is currently one of the most devastating diseases of wheat worldwide. The extent of sexual reproduction of this pathogen is well documented on bread wheat, but not on durum wheat. The objective of the present study was to quantify the occurrence of Z. tritici sexual reproduction on durum wheat in the Tunisian environment. The assessment was undertaken using a triple approach combining fruiting body assessment, ascospore trapping and population genetic analyses. The results highlighted the formation of pseudothecia on leaves and stubble from the autumn until the end of the growing season. Likewise, qPCR monitoring highlighted a constant release of Z. tritici airborne inoculum during the wheat-growing season, with a peak of production at the end of the season. Genetic investigations using microsatellites revealed high levels of gene and genotypic diversities, an equal distribution of mating types, and a lack of genetic clustering within and between growing seasons. Taken together, these findings indicate that Z. tritici undergoes sexual reproduction on durum wheat in Tunisia at least to the same extent than on bread wheat in Western Europe, and that the dry and warm climate does not affect the mating process of the fungus. Frequent occurrence of sexual reproduction is a valuable knowledge to take into account in STB control strategies on durum wheat. (C) 2019 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

International audience; Here we show that Bacillus pumilus ICVB403 recently isolated from copepod eggs is able to produce, after 48-72 h of growth in Landy medium, extracellular inhibitory compounds, which are active against Staphylococcus aureus ATCC 25923, methicillin-resistant S. aureus (MRSA) ATCC 43300, MRSA-S1, Staphylococcus epidermidis 11EMB, Staphylococcus warneri 27EMB, and Staphylococcus hominis 13EMB. Moreover, these extracellular inhibitory compound(s) were able to potentiate erythromycin against the aforementioned staphylococci. The minimum inhibitory concentration (MIC) of erythromycin was reduced from 32 mu g/mL to 8 mu g/mL for MRSA ATCC 43300 and MRSA SA-1 strains, and from 32-64 mu g/mL to 4 mu g/mL for S. epidermidis 11EMB and S. hominis 13EMB strains. The genome sequencing and analysis of B. pumilus ICVB403 unveiled 3.666.195 nucleotides contained in 22 contigs with a G + C ratio of 42.0%, 3.826 coding sequences, and 73 RNAs. In silico analysis guided identification of two putative genes coding for synthesis of surfactin A, a lipopeptide with 7 amino acids, and for a circular bacteriocin belonging to the circularin A/uberolysin family, respectively.

International audience; Lactococcus lactis is the most widely utilised starter bacterial species in dairy fermentations. The L. lactis cell envelope contains polysaccharides, which, among other known functions, serve as bacteriophage receptors. Our previous studies have highlighted the structural diversity of these so-called cell wall polysaccharides (CWPSs) among L. lactis strains that could account for the narrow host range of most lactococcal bacteriophages. In the present work, we studied the CWPS of L. lactis strain UC509.9, an Irish dairy starter strain that is host to the temperate and well-characterized P335-type phage Tuc2009. The UC509.9 CWPS structure was analyzed by methylation, deacetylation/deamination, Smith degradation and 2D NMR spectroscopy. The CWPS consists of a linear backbone composed of a tetrasaccharide repeat unit, partially substituted with a branched phosphorylated oligosaccharide having a common trisaccharide and three non-stoichiometric substitutions.

International audience; As a highly resistant polymer family, polyurethanes (PU) are responsible for increasing environmental issues. Then, PU biodegradation is a challenging way to develop sustainable waste management processes based on biological recycling. Since the metabolic diversity of fungi is a major asset for polymer degradation, nearly thirty strains were isolated from sampling on six different PU wastes-containing environments. A screening of the fungi on four thermoplastic PU (TPU) with different macromolecular architectures led to the selection of three strains able to use two polyester PU as sole carbon source: Alternaria sp., Penicillium section Lanata-Divaricata and Aspergillus section flavi. Weight loss, FT-IR, Scanning Electron Microscopy and Size Exclusion Chromatography analyses revealed that these three fungi degrade slightly and similarly a fatty acid dimer-based TPU while variability of degradation was noticed on a polycaprolactone-based TPU. On this last TPU, robust analysis of the degraded polymers showed that the Penicillium strain was the best degrading microorganism. Membrane enzymes seemed to be involved in this degradation. It is the first time that a strain of Penicillium of the section Lanata-Divaricata displaying PU biodegradation ability is isolated. These newly discovered fungi are promising for the development of polyester PU waste management process.

International audience; Lactobacilli strains are considered as a preventive means for treatment of vaginal infections or post-antibiotic treatment to repopulate the vaginal mucosa. This study aimed at establishing the vaginal lactobacillus profile of Algerian women with different vaginal diseases. Afterwards, lactobacilli isolated from swabs were in vitro characterized for their probiotic hallmarks. This prospective study allowed isolation of 44 Lactobacillus strains and 160 potentially pathogens, among which are Escherichia coli (50 isolates), Staphylococcus sp. (38 isolates), Enterococcus sp. (16 isolates), and Candida sp. (56 isolates). All Lactobacilli strains were characterized for their antagonism, adhesion to polystyrene, and resistance to acidity and bile. Consequently, six Lactobacillus strains (Lb. fermentum 5LB4, 5LB10, 5LB12, Lb. plantarum 5LB2, 5LB11, and Lactobacillus sp. 4LB9) were moderately or weakly adherent, and 35 potentially pathogens exhibited weak to strong adhesion to polystyrene. Antagonism was recorded for 36 Lactobacillus strains towards E. coli 6E2, S. aureus 7S3, Enterococcus sp. 5EN8, and Candida albicans C1 used as indicator organisms. Finally, Lb. fermentum 9LB6, 4LB16, and 10LB1 and Lb. plantarum 9LB4 were remarkable for their inhibitory activity, absence of hemolytic potential, and for their resistance to acidity (pH1.5) and bile (0.5%) harsh conditions.

International audience; Front-face fluorescence spectroscopy was used as a rapid tool for assessing freshness of whiting fish (Merlangius merlangus) fillets stored at 4 ± 1 °C for up to 12 days under different conditions. Some physicochemical analysis [i.e., water content, pH, peroxide value, thiobarbituric acid reactive substances (TBARS)] were performed. With increasing storage time, the TBARS and pH values increased progressively in all whiting fish fillets, in particular for those exposed to light. Principal component analysis and factorial discriminant analysis applied separately to the tryptophan (excitation: 290 nm, emission: 305–450 nm) and nicotinamide adenine dinucleotide (NADH) (excitation: 340 nm, emission: 360–600 nm) spectra gave only a slight discrimination between the investigated whiting fish fillets. These results were improved when data from all the fluorescence spectra were analyzed jointly, since nearly three-quarters of samples were correctly classified. The best results were obtained by concatenating the fluorescence and physicochemical data sets, giving more than 90% of correct classification.

In this study, we demonstrate the potential of Bacillus subtilis BBG111 to trigger ISR in rice (Oryza sativa L.) against Rhizoctonia solani, while there was no effect against Magnaporthe oryzae. We show that plant recognition of BBG111 induces jasmonic acid (JA) and ethylene (ET) as well as abscisic acid (ABA) and auxin signaling. In addition, B. subtilis supernatants also boosted immune responses triggered by chitin, suggesting that BBG111 triggers ISR at least in part by reinforcing basal plant defense responses. Finally, our results reveal an indispensable role of the BBG111 cyclic lipopeptides, fengycin and surfactin, in the induced defense state.

The physical properties of rennet-induced coagulation of preheated camel and cow milk gels (50 and 70 °C for 10 min) enriched with calcium chloride (CaCl2) and hydrogen phosphate dihydrate (Na2HPO42H2O) were evaluated using the dynamic low amplitude oscillatory shear analysis. The storage modulus (Gʹ) and loss modulus (Gʺ) of camel milk gels showed significant (P < 0·05) lower values than those of cow milk gels. The preheating of camel milk at 50 °C affected negatively the gelation properties, while the preheating at 70 °C prevented the formation of rennet-induced milk gels. No effect was observed on the gelation properties of cow milk gels. The CaCl2 added at 10 and 20 mM to preheated camel and cow milk reduced significantly (P < 0·05) the gelation time and increased the gel firmness. In contrast, Na2HPO42H2O added at 10 and 20 mM induced the formation of weak gels for preheated camel and cow milk at 50 °C, and even no gelation for preheated camel milk at 70 °C.

Nitrite is commonly used in meat products due to its plural technological advantages. However, it is controversial because of its detrimental side effects on health. Within the context of nitrite reduction, zinc protoporphyrin IX (Zn(II)PPIX) formation in meat products as natural red colouring agent has been suggested. This investigation presents the evaluation of naturally occurring pigments, namely Zn(II)PPIX, protoporphyrin IX (PPIX) and heme in nitrite-free dry fermented sausages in function of time, meat source (pork, horsemeat and a combination of both meat sources) and pH condition. In function of time, Zn(II)PPIX and PPIX were formed and heme content decreased. Higher pH conditions promoted Zn(II)PPIX and PPIX formation, whereas the influence of pH on heme was less clear. The use of horsemeat also promoted Zn(II)PPIX formation. Moreover, even similar amounts were formed when it was combined with pork. Product redness, however, could not be related to Zn(II)PPIX formation. ispartof: Meat Science vol:135 pages:46-53 ispartof: location:England status: published

National audience; In this study, we have investigated the effects of three lipopeptides (fengycin, surfactin and mycosubtilin) produced by different strains of Bacillus subtilis against the phytopathogenic fungi Fusarium oxysporum f. sp. iridacearum, which affects the ornamental bulb plant populations of Iris sp. The antifungal effects were tested using minimum inhibitory concentration assay, determination of mycelium growth and spore germination inhibition rates. Also, in vivo tests on infected rhizomes and scanning electron microscopy were employed. Mycosubtilin alone and in combination with fengycin or/and surfactin showed potent inhibitory activity at concentrations as low as 5gml(-1) which is 100 times lower compared to Topsin M, a common chemical fungicide frequently used against fusariosis in ornamental plants. An enhancement of mycosubtilin antifungal activity was observed when it was used in combination with surfactin due to a synergistic effect. At a concentration of 20gml(-1), mycosubtilin inhibited the growth of the mycelium up to 49% and the spore germination ability up to 26% in comparison to control. In addition, significant changes on the macro- and micro-morphology have been observed. The antifungal activity is related to the inhibition of spore germination and the irreversible damage of the hyphae cell wall. To the best of our knowledge, this is the first attempt to propose the lipopeptides as biopesticides against the fusariosis of ornamental plants.

Use of a membrane within a bioreactor (MBR), either microbial or enzymatic, is a technology that has existed for 30 years to increase process productivity and/or facilitate the recovery and the purification of biomolecules. Currently, this technology is attracting increasing interest in speeding up the process and in better sustainability. In this work, we present the current status of MBR technologies. Fundamental aspects and process design are outlined and emerging applications are identified in both aspects of engineering, i.e., enzymatic and microorganism (bacteria, animal cells, and microalgae), including microscale aspects and wastewater treatment. Comparison of this integrated technology with classical batch or continuous bioreactors is made to highlight the performance of MBRs and identify factors limiting their performance and the different possibilities for their optimization.

International audience; The rheological properties of acid-induced coagulation of camel and cow milk gels following the addition of calcium chloride (CaCl2) and hydrogen phosphate dehydrate (Na2HPO4*2H2O) were investigated using a dynamic low amplitude oscillatory rheology. For a considered condition, the final values of storage modulus (G′) and loss modulus (G″) of camel milk gels were significantly lower than those of cow milk gels. The increase of the added CaCl2 levels improved significantly the gelation properties of camel and cow milk gels, since a reduction in the gelation time and an increase in the gel firmness were observed. Following the addition of Na2HPO4*2H2O at 10 and 20 mM, no significant effect on the gelation rate and the firmness of camel milk gels was observed, while, a significant decrease in the gelation rate and firmness were observed for cow milk gels.

International audience; Ultrasound-assisted extraction (UAE) of antioxidant polyphenols from pomegranate peels (juice production by-products) was studied in an agitated extractor with ultrasound generator and temperature regulation. A mathematical model for multi-criteria optimization of UAE was proposed. This kinetic model permits the following and the prediction of polyphenols extraction yield, antioxidant activity of obtained extracts and energy consumption during extraction process in wide ranges of temperature (20-60 degrees C), ethanol content in the solvent (0-100% EtOH) and ultrasound power density (0-100 W/L). This model allows to visualize and understand the impacts of operating parameters on all three optimization criteria, as well as to find the operating conditions to attain a target extraction yield or antioxidant activity of the extract at minimum time or at minimum energy consumption. The advantage of ultrasound assistance was clearly demonstrated for the reduction of both extraction duration and energy consumption. The obtained high polyphenols yields and high antioxidant activity of the extracts confirmed the suitability of UAE for preparation of antioxidant-rich plant extracts at reduced time and energy from food industry by-products. (c) 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

International audience; The maintenance of the quality and safety of food products is a question of concern for food manufacturers, retailers, and consumers. The quality of these products could be determined by several analytical methods such as physicochemical and rheological ones. Although these analyses are promising techniques, they are time-consuming and need a lot of pollutant reagents. To reply to this request, the development of rapid spectroscopic methods (e.g., fluorescence and infrared) is of great importance. They are sensitive, nondestructive, rapid, environmentally friendly, etc., which makes them suitable for on-line or at-line process quality control. In addition, these techniques require limited sample preparation.

International audience; The aim of this study was to characterize the Listeria monocytogenes biofilm and particularly the nature of the carbohydrates in the biofilm extracellular matrix and culture supernatant versus to cell wall carbohydrates. Listeria monocytogenes serotype 1/2a and 4b strains were able to form complex biofilms embedded in an extracellular matrix. The soluble carbohydrates from biofilm extracellular matrix and culture supernatant were identified as teichoic acids, structurally identical to cell wall teichoic acids. In addition, the DSS 1130 BFA2 strain had a serotype 1/2a teichoic acid lacking N-acetyl glucosamine glycosylation due to a mutation in the lmo2550 gene. Consequently, we hypothesized that the extracellular teichoic acids in L. monocytogenes biofilms have the same origin as cell wall teichoic acid.

The self-assembly in aqueous solution of three lipopeptides obtained from Bacillus subtilis has been investigated. The lipopeptides surfactin, plipastatin and mycosubtilin contain distinct cyclic peptide headgroups as well as differences in alkyl chain length, branching and chain length distribution. Cryogenic transmission electron microscopy and X-ray scattering reveal that surfactin and plipastatin aggregate into 2 nm-radius spherical micelles, whereas in complete contrast mycosubtilin self-assembles into extended nanotapes based on bilayer ordering of the lipopeptides. Circular dichroism and FTIR spectroscopy indicate the presence of turn structures in the cyclic peptide headgroup. The unexpected distinct mode of self-assembly of mycosubtilin compared to the other two lipopeptides is ascribed to differences in the surfactant packing parameter. This in turn is due to specific features of the conformation of the peptide headgroup and alkyl chain branching.

International audience; Quality assessment of whiting (Merlangius merlangus) fillets stored in normal air (control group) and modified atmosphere packaging (MAP1: 50% N2/50% CO2 and MAP2: 80% N2/20% CO2) for up to 15 days at 4 °C was performed. The physico-chemical [pH, drip loss, moisture content, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS) and peroxide value (PV)], textural (i.e., hardness, fragility, gumminess, chewiness, springiness, cohesiveness), and color (i.e., L∗, a∗, b∗) parameters were determined. Front face fluorescence spectroscopy (FFFS) emission spectra were also scanned on the same samples with excitation set at 290 and 360 nm. The results indicated that MAP treatment, particularly MAP1 had an obvious preservative effect on fish quality by reducing pH value, TBARS and TVB-N contents, and retarding the softening of fish texture compared to control samples. Principal component analysis (PCA) applied to physico-chemical and instrumental data sets showed a clear discrimination of fish samples according to both their storage time and condition. A complete (100%) of correct classification was obtained by the concatenation of spectral, physico-chemical, and instrumental data sets. The results demonstrated that storage under MAP can be recommended to improve quality of whiting fillets, which in turn, can be evaluated by FFFS as a rapid and non-destructive technique.

SPE IPM UB INRA; National audience; Although there is a growing interest for the use of biostimulants in agriculture, only few methods allowing a precise description of their effects on plants have been reported. In the IRIS+ FUI project, two major and highly different worldwide crops, wheat (annual, monocotyledon) and grapevine (perennial, broadleaf), were chosen to deepen our knowledge of such compounds and explore their potential additional interest. The first objective is to develop in greenhouse conditions, a panel of tools and methods to study the impact of a series of biostimulants on the development (aerial and root system biomass measurements and corresponding phenotyping), and the physiology (photosynthetic activity, primary and secondary metabolites) of both plants. The second objective is to check if biostimulants, via their effects on the plant physiology, could be associated to resistance inducer-based control strategies against fungal aerial diseases. Unlike fungicides which directly target path! ogens, resistance inducers request plant metabolism dedicated to defense, a fitnesscostly process. Hence, an improvement of both crops' physiological status by biostimulation is expected to increase its responsiveness to resistance inducer application.

International audience; Neuroinflammatory processes are involved in the pathogenesis of many neurodegenerative disorders. Microglial cells, the main immune cells of the central nervous system, represent a target of interest to search for naturally occurring anti-inflammatory products. In this study, we evaluated the anti-inflammatory properties of polyphenols obtained from the stems of Morus alba. This edible species, known as white mulberry, is frequently studied because of its traditional use in Asian medicine and its richness in different types of polyphenols, some of which are known to be phytoalexins. One new coumarin glycoside, isoscopoletin 6-(6-O-β-apiofuranosyl-β-glucopyranoside) (1) was mainly isolated by CPC (centrifugal partition chromatography) from this plant, together with seven known polyphenols (2-8). Their structures were established on the basis of spectroscopic analyses including extensive 2D NMR studies. The eight isolated compounds were evaluated for their inhibitory activities on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. The absence of cell toxicity is checked by a MTT assay.

The use of surfactin and mycosubtilin as an eco-friendly alternative to control lettuce downy mildew caused by the obligate pathogen Bremia lactucae was investigated. Preliminary ecotoxicity evaluations obtained from three different tests revealed the rather low toxicity of these lipopeptides separately or in combination. The EC50 (concentration estimated to cause a 50 % response by the exposed test organisms) was about 100 mg L(-1) in Microtox assays and 6 mg L(-1) in Daphnia magna immobilization tests for mycosubtilin and 125 mg L(-1) and 25 mg L(-1) for surfactin, respectively. The toxicity of the mixture mycosubtilin/surfactin (1:1, w/w) was close to that obtained with mycosubtilin alone. In addition, the very low phytotoxic effect of these lipopeptides has been observed on germination and root growth of garden cress Lepidium sativum L. While a surfactin treatment did not influence the development of B. lactucae on lettuce plantlets, treatment with 100 mg L(-1) of mycosubtilin produced about seven times more healthy plantlets than the control samples, indicating that mycosubtilin strongly reduced the development of B. lactucae. The mixture mycosubtilin/surfactin (50:50 mg L(-1)) gave the same result on B. lactucae development as 100 mg L(-1) of mycosubtilin. The results of ecotoxicity as well as those obtained in biocontrol experiments indicated that the presence of surfactin enhances the biological activities of mycosubtilin. Mycosubtilin and surfactin were thus found to be efficient compounds against lettuce downy mildew, with low toxicity compared to the toxicity values of chemical pesticides. This is the first time that Bacillus lipopeptides have been tested in vivo against an obligate pathogen and that ecotoxic values have been given for surfactin and mycosubtilin.

International audience; The present work focused on the fodder yeast production, an attractive source of proteins for the livestock nutrition through the efficient growth of microorganisms on inexpensive waste substrates. Two agricultural by-products, sugar beet pulp and barley husks, rich in simple carbohydrates (88 g/L and 31.77 g/L for sugar beet hydrolysate and barley husks hydrolysate, respectively) were mixed after acid hydrolysis and used as a carbon and energy source for the "fodder yeast" Candida utilis production. Various nutritional requirements affecting the yeast growth were considered and investigated through an experimental design approach. The Response Surface Methodology was applied in order to optimize the medium composition aiming to increase on the one hand the yield on biomass rich in protein content and the substrate bioconversion on the other hand. Statistical analysis of the mathematical models developed for the studied response functions revealed a good correlation between the experimental data and the predicted values. In a medium containing 32-34 g/L reducing sugar, 1.022-1.079 g/L nitrogen and 0.406-0.427 g/L phosphorous, 6.47-6.62 g/L biomass were obtained. Under these conditions the final product protein content was of 50.40-51.55% (w/w) for a substrate consumption yield (expressed as monosaccharides content) of 92.94-95.4% (w/w).