Genome-Wide Profiling of Enterotoxigenic Staphylococcus aureus Strains Used for the Production of Naturally Contaminated Cheeses

peer-reviewedStaphylococcus aureus is a major human pathogen and an important cause of livestock infections. More than 20 staphylococcal enterotoxins with emetic activity can be produced by specific strains responsible for staphylococcal food poisoning, one of the most common food-borne diseases. Whole genome sequencing provides a comprehensive view of the genome structure and gene content that have largely been applied in outbreak investigations and genomic comparisons. In this study, six enterotoxigenic S. aureus strains were characterised using a combination of molecular, phenotypical and computational methods. The genomes were analysed for the presence of virulence factors (VFs), where we identified 110 genes and classified them into five categories: adherence (n = 31), exoenzymes (n = 28), genes involved in host immune system evasion (n = 7); iron uptake regulatory system (n = 8); secretion machinery factors and toxins’ genes (n = 36), and 39 genes coding for transcriptional regulators related to staphylococcal VFs. Each group of VFs revealed correlations among the six enterotoxigenic strains, and further analysis revealed their accessory genomic content, including mobile genetic elements. The plasmids pLUH02 and pSK67 were detected in the strain ProNaCC1 and ProNaCC7, respectively, carrying out the genes sed, ser, and selj. The genes carried out by prophages were detected in the strain ProNaCC2 (see), ProNaCC4, and ProNaCC7 (both positive for sea). The strain ProNaCC5 resulted positive for the genes seg, sei, sem, sen, seo grouped in an exotoxin gene cluster, and the strain ProNaCC6 resulted positive for seh, a transposon-associated gene. The six strains were used for the production of naturally contaminated cheeses which were tested with the European Screening Method for staphylococcal enterotoxins. The results obtained from the analysis of toxins produced in cheese, combined with the genomic features represent a portrait of the strains that can be used for the production of staphylococcal enterotoxin-positive cheese as reference material

How a Subclinical Unilateral Vestibular Signal Improves Binocular Vision

The present study aimed to determine if an infra-liminal asymmetric vestibular signal could account for some of the visual complaints commonly encountered in chronic vestibular patients. We used infra-liminal galvanic vestibular stimulation (GVS) to investigate its potential effects on visuo-oculomotor behavior. A total of 78 healthy volunteers, 34 aged from 20 to 25 years old and 44 aged from 40 to 60 years old, were included in a crossover study to assess the impact of infra-liminal stimulation on convergence, divergence, proximal convergence point, and stereopsis. Under GVS stimulation, a repeated measures ANOVA showed a significant variation in near convergence (p < 0.001), far convergence (p < 0.001), and far divergence (p = 0.052). We also observed an unexpected effect of instantaneous blocking of the retest effect on the far divergence measurement. Further investigations are necessary to establish causal relationships, but GVS could be considered a behavioral modulator in non-pharmacological vestibular therapies

V6 is active during antero-posterior but not in lateral galvanic vestibular stimulation.

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Neural correlates of chromostereopsis: an evoked potential study.

International audienceChromostereopsis is an illusion of depth arising from colour contrast: ocular chromatic aberrations usually make red appear closer to the viewer than blue. Whereas this phenomenon is widely documented from the optical and psychophysical point of view, its neural correlates have not been investigated. To determine the cortical processing of this colour-based depth effect, visual evoked potentials (VEPs) to contrasts of colour were recorded in 25 subjects. Chromostereopsis was found with the stimuli combining spectra extremes. VEP amplitude but not latency effects were observed to colour depth cues, suggesting an underlying, depth-specific slow negative wave, located using source modelling first in occipito-parietal, parietal, then temporal areas. The component was larger over the right hemisphere consistent with RH dominance in depth processing, likely due to context-dependent top-down modulation. These results demonstrate that the depth illusion obtained from contrast of colour implicates similar cortical areas as classic binocular depth perception

Galvanic vestibular stimulation modulates voluntary movement of the human upper body

We have investigated whether vestibular information plays a role in the control of voluntary movement of the upper body. Movement consisted of a lateral tilt of the upper body in the frontal plane through an angle of about 8 deg. The influence of vestibular input was assessed from the effect of long duration (3–6 s), low-intensity (0.7 mA) galvanic vestibular stimulation (GVS) applied at different times relative to the movement.GVS always produced a tilt of the body in the frontal plane but the response was larger and more prolonged when the onset of stimulation coincided with the cue to start moving compared with when it was applied some seconds after movement onset (i.e. while the subject was stationary in a tilted posture).When the stimulus began 2 s before the voluntary movement the response consisted of two distinct components separated in time, one that was linked to the onset of GVS and another that was linked to onset of the voluntary movement. The large response observed when GVS onset coincided with the movement cue resembled the sum (after realignment in time) of these two separate components.We suggest that these two components of the response to GVS relate to two different uses of vestibular information for whole-body control: first, to help maintain balance of the body, and second, to help guide and improve the accuracy of voluntary movements involving motion of the head in space

Collecting data on board French tropical tuna purse seiners with common observers : results of Orthongel's Voluntary Observer Program OCUP (2013-2017) in the Atlantic Ocean

International audienceIn order to comply with the different regulations and commitments requesting the presence of scientific observers onboard French purse seiners, and since it is not possible to embark more than one observer during a fishing trip, ORTHONGEL has imagined and implemented since July 2013 a program to facilitate and optimize the boarding of well-trained scientific observers. This voluntary program, called OCUP for "Observateur Commun Unique et Permanent" (Common Permanent Unique Observer) was conducted with the Institute for Research and Development (IRD), Oceanic Développement (OD) and several coastal countries. It was implemented in both Atlantic and Indian Oceans where the fleet adherent to ORTHONGEL is active. This paper describes the methodology of the OCUP program and presents and discusses its main results, focusing on the Atlantic Ocean. In the Atlantic Ocean, 43 scientific observers from 6 African countries have been trained as OCUP. Together with 39 French observers from IRD and OD, 37 of these African scientific observers have covered more than 300 trips until September 1 st , 2017 and the coverage of the French fleet has reached 100% since 2015. Since 2013, the OCUP program allows a better coverage of many fishing information such as bycatch or incidental catch and discards data but also provides the boat-owners information on the implementation of best practices aboard their vessels. Lessons learned from this program allow the authors to suggest a few recommendations.Afin de satisfaire aux différentes régulations et aux différents engagements pris par la flotte française de thoniers senneurs tropicaux, et puisqu'il n'est pas possible d'embarquer plus d'un observateur par marée, ORTHONGEL a imaginé et mis en place depuis 2013 un programme pour faciliter et optimiser l'embarquement d'observateurs scientifiques de bonne qualité. The programme volontaire, appelé OCUP (Observateur Commun Unique et Permanent) a été développé en collaboration avec l'Institut de Recherche pour le Développement (IRD), Oceanic Dévelopement (OD) et plusieurs pays côtiers. Le programme a été mis en place dans les océans Atlantique et Indien où est active la flotte de senneurs adhérente d'ORTHONGEL. Ce document décrit la méthodologie du programme OCUP et présente et discute ses principaux résultats, en se concentrant sur le cas de l'Océan Atlantique. Dans cet océan, 43 observateurs de 6 pays Africains ont été formés comme observateur OCUP. En complément des 39 observateurs français employés par l'IRD et OD, 37 de ces observateurs africains ont réalisé plus de 300 marées d'observation à ce jour et le taux de couverture des marées observées a atteint 100% en 2015. Depuis 2013, le programme OCUP permet une meilleure couverture de nombreuses informations telles que les prises accessoires, les prises accidentelles d'espèces sensibles ou encore les rejets. Le programme fournit également aux armements des informations utiles sur le respect des bonnes pratiques à bord. Sur la base du retour d'expérience du programme, les auteurs formulent quelques recommandations

Collecting data on board French tropical tuna purse seiners with common observers: results of Orthongel's voluntary observer program OCUP in the Atlantic Ocean (2013-2017)

In order to comply with the different regulations and commitments requesting the presence of scientific observers onboard French purse seiners, and since it is not possible to embark more than one observer during a fishing trip, ORTHONGEL has imagined and implemented since July 2013 a program to facilitate and optimize the boarding of well-trained scientific observers. This voluntary program, called OCUP for "Observateur Commun Unique et Permanent" (Common Permanent Unique Observer) was conducted with the Institute for Research and Development (IRD), Oceanic Développement (OD) and several coastal countries. It was implemented in both Atlantic and Indian Oceans where the fleet adherent to ORTHONGEL is active. This paper describes the methodology of the OCUP program and presents and discusses its main results, focusing on the Atlantic Ocean. In the Atlantic Ocean, 43 scientific observers from 6 African countries have been trained as OCUP. Together with 39 French observers from IRD and OD, 37 of these African scientific observers have covered more than 300 trips until September 1st, 2017 and the coverage of the French fleet has reached 100% since 2015. Since 2013, the OCUP program allows a better coverage of many fishing information such as bycatch or incidental catch and discards data but also provides the boat-owners information on the implementation of best practices aboard their vessels. Lessons learned from this program allow the authors to suggest a few recommendations

Parkinson’s patients can rely on perspective cues to perceive 3D space

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BtID -Outils pour identifier, tracer et contrôler les contaminants de Bacillus thuringiensis de la fourche à la fourchette

Bacillus thuringiensis ou Bt est une bactérie ubiquiste utilisée dans le domaine agricole en protection des cultures pour ses propriétés insecticides depuis les années 1950. Au niveau taxonomique, Bt appartient au groupe Bacillus cereus (sensu lato), qui contient également des souches pouvant être impliquées dans la qualité et sécurité des aliments. Même si l’utilisation de produits phytosanitaires à base de souches commerciales de Bt est un moyen efficace, facile d’utilisation et avantageux pour la protection des cultures, la persistance de spores sur les végétaux traités n’est pas toujours compatible avec les critères microbiologiques fixés pour leur utilisation dans les denrées alimentaires. Le projet BtID a permis (1) d’évaluer la diversité de B. thuringiensis et le positionnement de souches commerciales au sein du groupe B. cereus ; (2) de passer en revue les pratiques agricoles pour la protection des plantes à base de Bt ainsi que (3) de développer des méthodologies et outils d’aide à la décision permettant d’identifier, distinguer et tracer les souches de Bt autorisées au niveau européen, du champ à l’assiette. La collecte de ces souches commerciales a permis le séquençage du génome de trois représentants distincts majoritaires utilisés en biocontrôle, une caractérisation fine du comportement de ces souches hautement spécialisées, ainsi que d’étudier leur prévalence au niveau des matières premières (légumes) et produits finis (alimentaires transformés)