In vitro assessment of skin sensitization, irritability and toxicity of bacteriocins and reuterin for possible topical applications

Bacteriocins and reuterin are promising antimicrobials for application in food, veterinary, and medical sectors. In the light of their high potential for application in hand sanitizer, we investigated the skin toxicity of reuterin, microcin J25, pediocin PA-1, bactofencin A, and nisin Z in vitro using neutral red and LDH release assays on NHEK cells. We determined their skin sensitization potential using the human cell line activation test (h-CLAT). Their skin irritation potential was measured on human epidermal model EpiDerm™. We showed that the viability and membrane integrity of NHEK cells remained unaltered after exposure to bacteriocins and reuterin at concentrations up to 400 µg/mL and 80 mg/mL, respectively. Furthermore, microcin J25 and reuterin showed no skin sensitization at concentrations up to 100 µg/mL and 40 mg/mL, respectively, while pediocin PA-1, bactofencin A, and nisin Z caused sensitization at concentrations higher than 100 µg/mL. Tissue viability was unafected in presence of bacteriocins and reuterin at concentrations up to 200 µg/mL and 40 mg/ mL, respectively, which was confrmed by measuring cytokine IL-1α and IL-8 levels and by histological analysis. In conclusion, the current study provides scientifc evidence that some bacteriocins and reuterin, could be safely applied topically as sanitizers at recommended concentration

Gastrointestinal stability and cytotoxicity of bacteriocins from gram-positive and gram-negative bacteria : a comparative in vitro study

Bacteriocins are receiving increased attention as potent candidates in food preservation and medicine. Although the inhibitory activity of bacteriocins has been studied widely, little is known about their gastrointestinal stability and toxicity toward normal human cell lines. The aim of this study was to evaluate the gastrointestinal stability and activity of microcin J25, pediocin PA-1, bactofencin A and nisin using in vitro models. In addition cytotoxicity and hemolytic activity of these bacteriocins were investigated on human epithelial colorectal adenocarcinoma cells (Caco-2) and rat erythrocytes, respectively. Pediocin PA-1, bactofencin A, and nisin were observed to lose their stability while passing through the gastrointestinal tract, while microcin J25 is only partially degraded. Besides, selected bacteriocins were not toxic to Caco-2 cells, and integrity of cell membrane was observed to remain unaffected in presence of these bacteriocins at concentrations up to 400 µg/mL. In hemolysis study, pediocin PA-1, bactofencin A, and nisin were observed to lyse rat erythrocytes at concentrations higher than 50 µg/mL, while microcin J25 showed no effect on these cells. According to data indicating gastrointestinal degradation and the absence of toxicity of pediocin PA-1, bactofencin A, and microcin J25 they could potentially be used in food or clinical applications

Administration of probiotics influences F4 (K88)-positive enterotoxigenic Escherichia coli attachment and intestinal cytokine expression in weaned pigs

This study evaluated the effect of the probiotics Pediococcus acidilactici and Saccharomyces cerevisiae boulardii on the intestinal colonization of O149 enterotoxigenic Escherichia coli harbouring the F4 (K88) fimbriae (ETEC F4) and on the expression of ileal cytokines in weaned pigs. At birth, different litters of pigs were randomly assigned to one of the following treatments: 1) control without antibiotics or probiotics (CTRL); 2) reference group in which chlortetracycline and tiamulin were added to weanling feed (ATB); 3) P. acidilactici; 4) S. cerevisiae boulardii; or 5) P. acidilactici + S. cerevisiae boulardii. Probiotics were administered daily (1 × 109 CFU per pig) during the lactation period and after weaning (day 21). At 28 days of age, all pigs were orally challenged with an ETEC F4 strain, and a necropsy was performed 24 h later. Intestinal segments were collected to evaluate bacterial colonization in the small intestine and ileal cytokine expressions. Attachment of ETEC F4 to the intestinal mucosa was significantly reduced in pigs treated with P. acidilactici or S. cerevisiae boulardii in comparison with the ATB group (P = 0.01 and P = 0.03, respectively). In addition, proinflammatory cytokines, such as IL-6, were upregulated in ETEC F4 challenged pigs treated with P. acidilactici alone or in combination with S. cerevisiae boulardii compared with the CTRL group. In conclusion, the administration of P. acidilactici or S. cerevisiae boulardii was effective in reducing ETEC F4 attachment to the ileal mucosa, whereas the presence of P. acidilactici was required to modulate the expression of intestinal inflammatory cytokines in pigs challenged with ETEC F4

La nécropole tumulaire du Premier Age du Fer du Serre-de-Cabrié (Saint-André-de-Vézines, Aveyron)

The early Iron Age tumular necropolis at Serre-de-Cabrié (Saint-André-de-Vézines, Aveyron). The emergency excavation of the Serre-de-Cabrié necropolis has enabled the development of a research method which is a compromise between the central hole and the exhaustive excavation of the tumulus. The results add new data about the funeral rites in the early iron age inhumation tumuli on the Causse Noir. Analogies in architecture, burial features and offering deposits confer a definite homogeneous character to this necropolis dated between 700 and 550 B.C.La fouille de sauvetage de la nécropole du Serre-de-Cabrié a permis d’expérimenter une méthode d’investigation faisant un compromis entre le trou central et la fouille complète du tumulus. Les résultats obtenus apportent de nouvelles données sur les rites funéraires des tumulus à inhumation du Premier Age du Fer sur le causse Noir. Des analogies dans l’architecture, le mode d’ensevelissement et le dépôt des offrandes donnent une homogénéité certaine à cette nécropole datée entre 700 et 550 avant notre ère.Boutin Jean-Yves, Roux Jean-Claude, Crubézy Eric. La nécropole tumulaire du Premier Age du Fer du Serre-de-Cabrié (Saint-André-de-Vézines, Aveyron). In: Aquitania : une revue inter-régionale d'archéologie, tome 4, 1986. pp. 185-199

DÉVELOPPER DES COMPÉTENCES EN LITTÉRATIE VISUELLE ET MULTIMODALE PAR LE CROISEMENT DES DISCIPLINES HISTOIRE/FRANÇAIS/ARTS : L’ENQUÊTE CULTURELLE

La recherche dont il est question dans cet article rassemble des chercheurs qui, dans chacun de leur champ d’expertise (didactique de l’histoire, du français ou des arts), réfléchissent à la littératie et notamment à l’éducation à l’image considérée comme une condition de construction et d’accès à un savoir critique et réfléchi. À partir d’ensembles multimodaux (Domingo, Jewitt et Kress, 2015), organisés sous forme d’enquêtes culturelles (Sala, Villagordo et Halimi, 2015), l’étude réalisée met en lumière les savoirs et surtout les pratiques que des enseignants (n = 10), québécois et français, et leurs élèves mettent en oeuvre lorsqu’il leur est demandé de s’investir dans des situations d’enseignement/apprentissage qui exigent de traiter des documents variés ayant une thématique historique partagée. Plus spécifiquement, les données descriptives obtenues par cette étude de cas multiples permettent d’éclairer la sélection par les enseignants et l’appréciation par les élèves des documents, surtout visuels, retenus dans un contexte d’enquête culturelle, l’accompagnement pédagogique (fort modeste) de la lecture des images et l’apport de l’enquête culturelle comme dispositif d’éducation à l’image.This paper is the preliminary result of a study in education that was conceived and conducted by four researchers from different disciplinary backgrounds (social studies in education, applied linguistics & communication, art education). The specific aim of the study was to develop a common ground in order to build a collective framework for literacy teaching and learning, relying on the importance of images. Based on different multimodal ensembles (Domingo, Jewitt & Kress, 2015) that were part of what these researchers called cultural inquiries, these multiple case studies (N = 10 classes from France and Quebec) show how cultural knowledge, teaching practices, and learning strategies work together when there is an explicit and collective task of processing historical visual data. In the end, cultural inquiries enhance image reading and, moreover, cleverly support visual literacy teaching

Northward Pathway Across the Tropical North Pacific Ocean Revealed by Surface Salinity: How do El Niño Anomalies Reach Hawaii?

International audienceUsing the unprecedented 7 year monitoring of sea surface salinity (SSS) from the Soil Moisture Ocean Salinity (SMOS) satellite mission, an unexpected large‐scale anomaly at 20°N is studied in the tropical Pacific Ocean following the 2015‐2016 extreme El Niño event. This basin‐wide negative anomaly (below −0.3) is present in October 2015 between 15 and 25°N, reaching the Hawaiian archipelago. It has not been previously observed during El Niño events. It is accompanied by a negative equatorial SSS anomaly at the dateline (below −0.5) which has been previously described as an El Niño‐associated SSS anomaly. A wide range of observations (in situ and space‐borne) and a state‐of‐the‐art ocean model simulation are used together to characterize and understand the mechanisms leading to this singular SSS signal. The extra‐equatorial negative SSS anomaly is found to be a superposition of a persisting SSS anomaly due to the 2014 weak El Niño and of the larger 2015‐2016 El Niño SSS anomaly. Both were advected northward in the tropical current system by the mean Ekman currents and hypothetically by instabilities in the zonal currents patterns. An analysis of analogous structures in the past 20 years shows that this northward displacement of SSS anomalies is not El Niño specific, even if their advection is enhanced during El Niño events. This study shows that when surface freshwater fluxes are weak SSS, unlike sea surface temperature, can be used to trace water mass displacement for up to 20 months

The antiquity of cranial surgery in Europe and in the Mediterranean basin

Through personal observations and a literature study we have made a synthesis of the most ancient healed trephinations in Europe and in the Mediterranean basin. Cases of small dimensions that were carried out with simple techniques are found in the Mesolithic populations from North Africa, Ukraine and Portugal. The first Neolithic examples of trephinations are extensive and have been realised with more sophisticated techniques. This suggests that the development of agriculture was accompanied by the command of new procedures in the field of surgery.http://www.sciencedirect.com/science/article/B6VJ3-42VM9MY-8/1/67dcf2f089abb7c7a878392eb1dfc3c

Les collections scientifiques de l'université Bordeaux 1. Sciences et Technologies

De nombreuses universités scientifiques possèdent des collections. L'université Bordeaux 1 possède neuf grandes collections concernant les domaines de la préhistoire, de l'anthropologie, de la géologie terrestre et marine, de la paléontologie et micropaléontologie, de la biologie, de l'astronomie et d'un fonds ancien et moderne d'ouvrages scientifiques. Certaines collections sont riches de milliers de spécimens : fossiles d'invertébrés, ossements de vertébrés, silex taillés, ossements humains préhistoriques ou historiques, animaux naturalisés, carottes de sédiments, instruments d'astronomie et livres anciens. Ces collections ont été constituées par des privés ou des chercheurs et ont ensuite été léguées à l'université. Il est important d'identifier les collectionneurs et surtout les motivations qui ont guidé leurs choix : recherche, enseignement, passion. Entre histoires personnelles et histoires locales, ce regard sur les collections est aussi une porte ouverte sur l'histoire des Sciences