Illkirch-Graffenstaden, France
Illkirch-Graffenstaden, France

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Hamon E.,University of Strasbourg | Horvatovich P.,University of Groningen | Izquierdo E.,University of Strasbourg | Bringel F.,University of Strasbourg | And 3 more authors.
BMC Microbiology | Year: 2011

Background: Lactic acid bacteria are commonly marketed as probiotics based on their putative or proven health-promoting effects. These effects are known to be strain specific but the underlying molecular mechanisms remain poorly understood. Therefore, unravelling the determinants behind probiotic features is of particular interest since it would help select strains that stand the best chance of success in clinical trials. Bile tolerance is one of the most crucial properties as it determines the ability of bacteria to survive in the small intestine, and consequently their capacity to play their functional role as probiotics. In this context, the objective of this study was to investigate the natural protein diversity within the Lactobacillus plantarum species with relation to bile tolerance, using comparative proteomics. Results: Bile tolerance properties of nine L. plantarum strains were studied in vitro. Three of them presenting different bile tolerance levels were selected for comparative proteomic analysis: L. plantarum 299 V (resistant), L. plantarum LC 804 (intermediate) and L. plantarum LC 56 (sensitive). Qualitative and quantitative differences in proteomes were analyzed using two-dimensional electrophoresis (2-DE), tryptic digestion, liquid chromatography-mass spectrometry analysis and database search for protein identification. Among the proteins correlated with differences in the 2-DE patterns of the bacterial strains, 15 have previously been reported to be involved in bile tolerance processes. The effect of a bile exposure on these patterns was investigated, which led to the identification of six proteins that may be key in the bile salt response and adaptation in L. plantarum: two glutathione reductases involved in protection against oxidative injury caused by bile salts, a cyclopropane-fatty-acyl-phospholipid synthase implicated in maintenance of cell envelope integrity, a bile salt hydrolase, an ABC transporter and a F0F1-ATP synthase which participate in the active removal of bile-related stress factors. Conclusions: These results showed that comparative proteomic analysis can help understand the differential bacterial properties of lactobacilli. In the field of probiotic studies, characteristic proteomic profiles can be identified for individual properties that may serve as bacterial biomarkers for the preliminary selection of strains with the best probiotic potential. © 2011 Hamon et al; licensee BioMed Central Ltd.


Coton M.,ADRIA Normandie | Delbes-Paus C.,French National Institute for Agricultural Research | Irlinger F.,French National Institute for Agricultural Research | Desmasures N.,University of Caen Lower Normandy | And 4 more authors.
Food Microbiology | Year: 2012

The goal of this study was to identify at the species level a large collection of Gram-negative dairy bacteria isolated from milks or semi-hard and soft, smear-ripened cheeses (cheese core or surface samples) from different regions of France. The isolates were then assessed for two risk factors, antibiotic resistance and volatile and non-volatile biogenic amine production in vitro. In total, 173 Gram-negative isolates were identified by rrs and/or rpoB gene sequencing. A large biodiversity was observed with nearly half of all Gram-negative isolates belonging to the Enterobacteriaceae family. Overall, 26 different genera represented by 68 species including potential new species were identified among the studied Gram-negative isolates for both surface and milk or cheese core samples. The most frequently isolated genera corresponded to Pseudomonas, Proteus, Psychrobacter, Halomonas and Serratia and represented almost 54% of the dairy collection. After Pseudomonas, Chryseobacterium, Enterobacter and Stenotrophomonas were the most frequently isolated genera found in cheese core and milk samples while Proteus, Psychrobacter, Halomonas and Serratia were the most frequently isolated genera among surface samples. Antibiotic resistance profiles indicated that resistances to the aminosid, imipemen and quinolon were relatively low while more than half of all tested isolates were resistant to antibiotics belonging to the monobactam, cephem, fosfomycin, colistin, phenicol, sulfamid and some from the penam families. Thirty-six% of isolates were negative for in vitro biogenic amine production. Among biogenic amine-producers, cadaverine was the most frequently produced followed by isoamylamine, histamine and putrescine. Only low levels (<75 mg/l) of tyramine were detected in vitro. © 2011 Elsevier Ltd.


Hamon E.,University of Strasbourg | Horvatovich P.,University of Groningen | Bisch M.,University of Strasbourg | Bringel F.,University of Strasbourg | And 3 more authors.
Journal of Proteome Research | Year: 2012

The identification of cell determinants involved in probiotic features is a challenge in current probiotic research. In this work, markers of bile tolerance in Lactobacillus casei were investigated using comparative proteomics. Six L. casei strains were classified on the basis of their ability to grow in the presence of bile salts in vitro. Constitutive differences between whole cell proteomes of the most tolerant strain (L. casei Rosell-215), the most sensitive one (L. casei ATCC 334), and a moderately tolerant strain (L. casei DN-114 001) were investigated. The ascertained subproteome was further studied for the six strains in both standard and bile stressing conditions. Focus was on proteins whose expression levels were correlated with observed levels of bile tolerance in vitro, particularly those previously reported to be involved in the bile tolerance process of lactobacilli. Analysis revealed that 12 proteins involved in membrane modification (NagA, NagB, and RmlC), cell protection and detoxification (ClpL and OpuA), as well as central metabolism (Eno, GndA, Pgm, Pta, Pyk, Rp1l, and ThRS) were likely to be key determinants of bile tolerance in L. casei and may serve as potential biomarkers for phenotyping or screening purposes. The approach used enabled the correlation of expression levels of particular proteins with a specific probiotic trait. © 2011 American Chemical Society.


Grant
Agency: European Commission | Branch: FP7 | Program: CSA | Phase: ICT-2011.3.2 | Award Amount: 1.13M | Year: 2011

The overall objective of FoodMicroSystems is to initiate the implementation of microsystems & smart miniaturised systems in the food sector by improving cooperation between suppliers and users of microsystems for food/beverage quality and safety. The project has five specific objectives:\n\n1.\tTo improve the coordination of national and EU programmes for the development of food applications\n2.\tTo facilitate cooperation of the value chain actors from research to industrialisation of smart systems in the food sector\n3.\tTo promote industrial take-up actions in the food sector\n4.\tTo develop roadmaps linking applications and technologies\n5.\tTo promote international cooperation\n\nThe project is structured into 5 main work- packages (WPs). WP1 (Current state of play) will identify partners for international cooperation as well as examples of existing MST applications in the food sector. WP2 (Research inventory) will provide an analysis of MST research programmes and activities in regards to food applications. WP3 (Food industry demands and constraints) will study the needs of the food industry, the economic and technical constraints, the perception of the consumers as well as the ethical and regulation context. WP4 (Roadmapping) will develop detailed research and application roadmaps for three food chains. WP5 (Communication and exploitation) aims at communicating the projects results through dissemination, presentations, information campaigns and training.\n\nThe consortium includes key research players in both the food and the microsystems sectors. FoodMicroSystems is an open project that will associate industry and other stakeholders in its activities.


Coton E.,ADRIA Normandie | Desmonts M.-H.,Aerial | Leroy S.,French National Institute for Agricultural Research | Coton M.,ADRIA Normandie | And 5 more authors.
International Journal of Food Microbiology | Year: 2010

In this study, the biodiversity of Coagulase-Negative Staphylococci (CNS) strains isolated in France from cheese related samples (227 isolates) and dry sausage related samples (204 isolates) was compared to the biodiversity of 297 clinical isolates. Species identification was performed using different molecular methods (specific PCR, "Staph array" hybridization and sodA gene sequencing). Infraspecific biodiversity of strains belonging to the main CNS species found in both food and clinical samples was then assessed by pulse-field gel electrophoresis (PFGE). For food-related samples, the main species encountered corresponded to Staphylococcus equorum (28.5%), S. xylosus (28.3%), S. saprophyticus (12.5%) and S. succinus (7.7%); while, for clinical isolates, the main species encountered corresponded to S. epidermidis (69.4%), S. capitis (9.8%), S. hominis (4.5%), S. warneri (4.5%) and S. haemolyticus (3.8%). The two main species common to both food and clinical samples corresponded to S. epidermidis and S. saprophyticus. Concerning infraspecific biodiversity, PFGE profiles of S. equorum, S. saprophyticus and S. epidermidis showed a large genomic biodiversity. Comparatively, S. xylosus exhibited a lower biodiversity. No correlation could be observed between PFGE patterns and either the geographical origin or the sample type. This study highlighted that no food strains had similar PFGE profiles to clinical ones and that the two main food-related species, S. equorum and S. xylosus, were not found in clinical samples. The identification of CNS species and the characterisation of the genetic diversity of the strains constitute a first step towards CNS safety assessment. © 2009 Elsevier B.V. All rights reserved.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: NMP-2008-2.5-2 | Award Amount: 4.31M | Year: 2009

The present project aims to establish a European Consortium bringing together leading experts in the fields of computational materials modelling, experimental materials research and industrial development of high-performance glass materials. The scientific and technological activities of the consortium shall be devoted to improving the efficiency, functionality and reliability of glass products for pharmaceutical and thin-layer optical and photovoltaic applications. The scope of the work will be to gain a detailed, atomic-scale knowledge of chemical and physical processes taking place at glassy interface systems. The Consortium will further develop a recently proposed atomistic modelling method which spans across multiple time and size simulation scales bridging the quantum-mechanical with the classical level of precision. The method will be applied to two scientific problems which require quantum precision and very large model system sizes. We will investigate (i) the adhesion between a glassy SiO2 phase and a protein-containing water solution, relevant to pharmaceutical applications and (ii) the cohesion between a glassy SiO2 phase and a TiO2-based coating layer, relevant to thin-layer optical or photovoltaic applications. The theoretical work will be carried out in close coordination with experimental activity. Novel materials will be designed and implemented into product prototypes within the R&D infrastructure of a leading European glass-producing company on the basis of the acquired knowledge. Our results will be disseminated through scientific papers, workshops and training activities especially designed for members of the industrial sector as well as for the scientific academic community.


Bousserouel S.,University of Strasbourg | Le Grandois J.,AERIAL | Gosse F.,University of Strasbourg | Werner D.,AERIAL | And 4 more authors.
International Journal of Oncology | Year: 2013

Shoots of white asparagus are a popular vegetable dish, known to be rich in many bioactive phytochemicals reported to possess antioxidant, and anti-inflammatory and antitumor activities. We evaluated the anticancer mechanisms of a methanolic extract of Asparagus officinalis L. shoots (Asp) on human colon carcinoma cells (SW480) and their derived metastatic cells (SW620), and Asp chemopreventive properties were also assessed in a model of colon carcinogenesis. SW480 and SW620 cell proliferation was inhibited by 80% after exposure to Asp (80 μg/ml). We demonstrated that Asp induced cell death through the activation of TRAIL DR4/DR5 death receptors leading to the activation of caspase-8 and caspase-3 and to cell apoptosis. By specific blocking agents of DR4/DR5 receptors we were able to prevent Asp-triggered cell death confirming the key role of DR4/DR5 receptors. We found also that Asp (80 μg/ml) was able to potentiate the effects of the cytokine TRAIL on cell death even in the TRAIL-resistant metastatic SW620 cells. Colon carcinogenesis was initiated in Wistar rats by intraperitoneal injections of azoxymethane (AOM), once a week for two weeks. One week after (post-initiation) rats received daily Asp (0.01%, 14 mg/kg body weight) in drinking water. After 7 weeks of Asp-treatment the colon of rats exhibited a 50% reduction of the number of preneoplastic lesions (aberrant crypt foci). In addition Asp induced inhibition of several pro-inflammatory mediators, in association with an increased expression of host-defense mediators. In the colonic mucosa of Asp-treated rats we also confirmed the pro-apoptotic effects observed in vitro including the activation of the TRAIL death-receptor signaling pathway. Taken together, our data highlight the chemopreventive effects of Asp on colon carcinogenesis and its ability to promote normal cellular homeostasis.


Wilson A.E.,University of Strasbourg | Bergaentzle M.,University of Strasbourg | Bindler F.,University of Strasbourg | Marchioni E.,University of Strasbourg | And 2 more authors.
Food Control | Year: 2013

The antimicrobial activities of ten isothiocyanates (ITCs), namely sulforaphane, iberin, allyl-, benzyl-, methyl-, phenyl-, phenylethyl-, propyl-, 3-methylthiophenyl-, and 3-methylthiopropyl-ITC, were tested against a range of pathogenic and food spoilage bacteria. The activities of six ITCs were investigated for the first time. The growth of the bacteria was monitored by turbidimetry in a culture broth with increasing concentrations of ITCs. An antimicrobial efficacy index (I AE) was calculated based on the observed growth delay, reduction in maximum growth rate and reduction in population size. ITCs inhibited pathogenic and food spoilage bacteria including species from Bacillus, Escherichia, Klebsiella, Listeria, Salmonella, Serratia and Staphylococcus. Gram-negative bacteria were overall more sensitive to ITCs than their Gram-positive counterparts: the three most sensitive species with five ITCs, and two out of three most sensitive species with the other ITCs. Yet, the species of a bacterium seemed to play a more important role, since considerable variations in sensitivity were observed between species even within the same Gram type. All ITCs investigated displayed antimicrobial activity, but with levels that depended on the target bacteria and the molecule considered. The highest I AE values were obtained with Benzyl-ITC, followed by phenylethyl-ITC, but this was not necessarily the case with all aromatic ITCs. An aliphatic compound, 3-methylthiopropyl-ITC, was much more active than phenyl-ITC and 3-methylthiophenyl-ITC. Within a structural group, the activity of ITCs varied dramatically, and structural features, like the presence of a sulfinyl group, the molecule size, and the length of the hydrocarbon chain, seem to be of importance. © 2012 Elsevier Ltd.


The antioxidant capacity of 9 pure lipophilic compounds was examined by microplate-ABTS and HPLC-ABTS, using similar experimental conditions. Results obtained showed that HPLC-ABTS method can be used for a rapid determination of individual antioxidant capacity of compounds in standard solutions or complex mixtures. The application of both methods to real lipophilic extracts from tomato (Solanum lycopersicum L.), green and red peppers (Capsicum annuum) reveals possible interactions between antioxidants. Thus, synthetic mixtures of two compounds identified in tomato and peppers were measured using microplate-ABTS and HPLC-ABTS. Synergistic effects were observed between (-carotene-capsanthin) (1:9) and (1:1), (-tocopherol-capsanthin) (1:9), (lutein-lycopene) (9:1) and (capsanthin--tocopherol) (9:1). On the contrary, antagonistic effects were observed for (lutein--tocopherol) and (-tocopherol--tocopherol). The interactions observed with two-compound mixtures are not systematically observed in the natural lipophilic extracts from tomato, green and red peppers, probably since extracts are more complex and are susceptible to cause interferences.


Kuntz F.,Aerial | Strasser A.,Aerial
Radiation Physics and Chemistry | Year: 2016

Dose measurement applied to food irradiation is obviously a very important and critical aspect of this process. It is described in many standards and guides. The application of appropriate dosimetry tools is explained. This helps to ensure traceability of this measurement and number of dosimeters available on the market are well studied even though theirs response should be characterized while used in routine processing conditions. When employed in low energy radiation fields, these dosimeters may exhibit specific response compared to the usual Cobalt 60 source irradiation. Traceable calibration or correction factor assessment of this energy dependency is mandatory. It is to mention that the absorbed dose is measured in the dosimeter itself and unfortunately not in/on the food product. However, existing dosimetry systems fulfill all relevant requirements. © 2016

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