Aspergillus westerdijkiae polyketide synthase gene “aoks1” is involved in the biosynthesis of ochratoxin A

OchratoxinA (OTA) is a potential nephrotoxic, teratogenic, immunogenic, hepatotoxic and carcinogenic mycotoxin, produced by Aspergillus westerdijkiae NRRL 3174. Herein we describe the characterization of a putative OTA-polyketide synthasegene “aoks1”, cloned by using gene walking approach. The predicted amino acid sequence of the 2 kb clone display 34–60% similarities to different polyketide synthasegenes including lovastatine biosynthesis gene “lovb” in A. terreus, compactin biosynthesis gene “mlcA” in Penicillium citrinum and OTA biosynthesis gene “otapksPN” in P. nordicum. Based on the reverse transcription PCR and kinetic secondary metabolites production studies, aoks1 expression was found to be associated with OTA biosynthesis. Further a mutant, in which the aoks1gene was inactivated by Escherichia coli hygromycin B phosphotransferase gene, lost the capacity to produce OTA, but still producing mellein. To our knowledge this report describes for the first time characterization of a gene involved in OTA biosynthesis, with the information about mellein which was proposed in the literature to be an intermediate OTA. This study also suggests that aoks1 may be the second polyketide synthase gene required for OTA biosynthesis in A. westerdijkiae NRRL 3174

Review of mycotoxin reduction in food and feed: from prevention in the field to detoxification by adsorption or transformation

Mycotoxins are secondary metabolites present worldwide in agricultural commodities and produced by filamentous fungi that cause a toxic response (mycotoxicosis) when ingested by animals. Prevention of mycotoxicoses includes pre- and post-harvest strategies. The best way to reduce the mycotoxin content in food and feed is the prevention of mycotoxin formation in the field, but this is often not sufficient, so other methods are needed. To decontaminate and/or detoxify mycotoxin-contaminated food and feed, the most prevalent approach in the feed industry is the inclusion of sorbent materials in the feed thus obtaining more or less selective removal of toxins by adsorption during passage through the gastrointestinal tract. Another reliable approach is to add enzymes or microorganisms capable of detoxifying some mycotoxins. Through a comprehensive review of published reports on the strategies for mycotoxin removal, this present work aims to update our understanding of mycotoxin removal. It provides an insight into the detoxification of mycotoxin present in food and feed. In the future, more emphasis needs to be placed on adsorption of mycotoxins in the gastrointestinal tract. Concerning the enzymatic transformation of mycotoxins, further efforts are required in understanding detoxification reactions, the toxicity of transformation products and in the characterization of enzymes responsible for transformations

Quatre voies pour aller plus loin.

National audienceIl s'agit ici de tirer parti des réflexions dont ce numéro est riche pour tracer quelques pistes, non exhaustives, permettant d'améliorer les synergies entre agronomes et économistes pour aller vers des agricultures plus conformes aux attentes de la société. Nous proposons que les échanges ouverts lors des Entretiens du Pradel et dans ce numéro de la revue AE&S se poursuivent selon quatre voies. La première voie est celle de l'approfondissement théorique et méthodologique. Les agronomes n'ont pas tous le même point de vue sur l'exploitation agricole, et les économistes non plus. Il existe cependant des ancrages à des hypothèses disciplinaires, qui probablement distinguent les deux communautés au-delà des nuances que chacune reconnaît en son sein. La seconde voie est celle de l'extension du domaine de la collaboration. Le couple exploitation agricole/politiques publiques a délibérément été positionné au centre de ce numéro. C'est à partir de l'analyse concrète d'exploitationsagricoles et de leurs trajectoires que le dialogue était le plus facile à mener. On s’est accordé à souligner l’importance d’approfondir cette analyse commune du fonctionnement de l’exploitation trop délaissée aujourd’hui. Certains points paraissent mériter une attention particulière : le lien entrel’évolution des structures d’exploitation et l’évolution des techniques culturales, le travail et ses différentes dimensions : technicité, compétence, apprentissage, etc. En surplomb de ces deux premières voies en existe une troisième, qui est celle des données sur lesquelles agronomes et économistes pourraient collaborer. Dépasser l'analyse de monographies d'exploitations, si fructueuse soit-elle, semble une nécessité pour parvenir à des résultats porteurs d'une représentativité, nécessaires pour l'action. Cela passe par l'élaboration d'un appareil de données organisées, au minimum à l'échelle nationale. Enfin la dernière perspective que nous souhaitons évoquer est celle du travail en commun sur des scénarios d'évolution des agricultures

Single-Atom Addressing in Microtraps for Quantum-State Engineering using Rydberg Atoms

We report on the selective addressing of an individual atom in a pair of single-atom microtraps separated by $3\;\mu$m. Using a tunable light-shift, we render the selected atom off-resonant with a global Rydberg excitation laser which is resonant with the other atom, making it possible to selectively block this atom from being excited to the Rydberg state. Furthermore we demonstrate the controlled manipulation of a two-atom entangled state by using the addressing beam to induce a phase shift onto one component of the wave function of the system, transferring it to a dark state for the Rydberg excitation light. Our results are an important step towards implementing quantum information processing and quantum simulation with large arrays of Rydberg atoms.Comment: 4 pages, 3 figure

The impact of price display on perceptions of luxury: a masstige perspective

Based on two experimental studies in which college students participated, this paper investigates the impact of price display in the luxury sector on low-end brands perceived luxury and attitude. In Study 1, we show that price display is associated with higher perceived quality, uniqueness, and conspicuousness for a fictitious low-end brand. In Study 2, we confirm this positive influence for a real low-end brand, and show that it transfers to brand attitude through perceived quality and conspicuousness. In addition, Study 2 indicates no negative effect of price display on perceptions of luxury for a higher level brand. In a pioneering attempt to evaluate the effects of price display in the luxury sector, this paper adds value to the body of literature on luxury brand management. Besides, it provides insight to managers of luxury brands of different range levels on the effects of price display, a practice that develops as more and more luxury companies engage in masstige strategies or open commercial websites

Single-atom trapping in holographic 2D arrays of microtraps with arbitrary geometries

We demonstrate single-atom trapping in two-dimensional arrays of microtraps with arbitrary geometries. We generate the arrays using a Spatial Light Modulator (SLM), with which we imprint an appropriate phase pattern on an optical dipole trap beam prior to focusing. We trap single $^{87}{\rm Rb}$ atoms in the sites of arrays containing up to $\sim100$ microtraps separated by distances as small as $3\;\mu$m, with complex structures such as triangular, honeycomb or kagome lattices. Using a closed-loop optimization of the uniformity of the trap depths ensures that all trapping sites are equivalent. This versatile system opens appealing applications in quantum information processing and quantum simulation, e.g. for simulating frustrated quantum magnetism using Rydberg atoms.Comment: 9 pages, 10 figure

Sécurité et mobilité des adolescents piétons dans l'espace urbain : l'exemple de la communauté urbaine de Lille

Little is known on the detailed characteristics of the mobility and accidents of pedestrian teenagers in France. The safety of pedestrians aged 10 to 15 years has been less studied in the literature than that of younger pedestrians, yet nowadays this age group corresponds to the highest victim rate for pedestrian accidents. The assumption is that this higher rate is due in part to the peculiarities of their mobility and their use of urban space. Through a spatial analysis of the territory of the Lille metropolitan area, this article provides insights into the determinants of this specific involvement of adolescents in pedestrian accidents. This work is based on accident data obtained through the analysis of police reports on injury accidents (occurred in the Lille metropolitan area for the period 2002-2011), and mobility data from the 2006 survey on households' travel activities carried out by the authorities of the Lille metropolitan area. The results highlight the importance of the factors related to the exposure to traffic in the involvement of adolescents in pedestrian accidents. The spatial analysis also reveals specific concentrations of adolescent pedestrian accidents in suburban areas near to urban centers. Finally, through the detailed accident analysis, the main processes leading to accidents involving adolescent pedestrians are identified, as well as the role of some characteristics of infrastructure and spatial contexts in these processes.Les caractéristiques fines de la mobilité et de l'accidentologie des adolescents piétons sont peu connues en France. La sécurité des piétons âgés de dix à quinze ans a été moins étudiée dans la littérature scientifique que celle des plus jeunes piétons, pourtant cette tranche d'âge constitue aujourd'hui la population avec le plus fort taux de victimes piétonnes. L'hypothèse est faite que l'insécurité des piétons adolescents tient en partie à des spécificités de leurs pratiques de mobilité à pied et de leurs usages de l'espace urbain. À travers une analyse spatiale exploratoire sur le terrain d'étude de la communauté urbaine lilloise, cet article apporte des enseignements sur les déterminants de l'implication particulière des adolescents dans les accidents de piétons. Ce travail s'appuie sur un corpus de données d'accidents (résultant de l'analyse des procès-verbaux d'accidents ayant eu lieu entre 2002 à 2011 dans la communauté urbaine de Lille), et des données de mobilité issues de l'enquête ménages-déplacements de la communauté urbaine de 2006. Les résultats montrent l'importance des facteurs d'exposition au trafic des piétons adolescents, dans leur implication dans des accidents. L'analyse spatiale fait également apparaître des concentrations spécifiques d'accidents de piétons adolescents dans les secteurs de proche banlieue des centres urbains. Enfin, l'analyse détaillée des accidents permet de mettre en évidence les principaux processus conduisant aux collisions impliquant des piétons adolescents, et le rôle de certaines caractéristiques d'infrastructure et certains contextes spatiaux dans ces processus