Original observations of Desmozoon lepeophtherii, a microsporidian hyperparasite infecting the salmon louse Lepeophtheirus salmonis, and its subsequent detection by other researchers

A microsporidian hyperparasite, Desmozoon lepeophtherii, of the parasitic copepod Lepeophtheirus salmonis (salmon louse), infecting farmed Atlantic salmon (Salmo salar), was first discovered in the west of Scotland in 2000. Heavily infected salmon lice are easily recognised as they have large opaque inclusions distributed throughout the body. The prevalence of salmon lice with visible signs of microsporidiosis can be up to 10% of the population from certain farm sites. The microsporidian was also isolated from the host Atlantic salmon suggesting it may have a two host life cycle. The authors believe that the infection in immunocompetent salmon may be latent, becoming acute during periods of infection with another pathogen or during sexual maturation. Since its first discovery in Scotland, Desmozoon lepeophtherii has been subsequently reported from Norway, and more recently from the Pacific coast of North America

Clostridium botulinum type C, D, C/D, and D/C: An update

Clostridium botulinum is the main causative agent of botulism, a neurological disease encountered in humans as well as animals. Nine types of botulinum neurotoxins (BoNTs) have been described so far. Amongst these “toxinotypes,” the A, the B and E are the most frequently encountered in humans while the C, D, C/D and D/C are mostly affecting domestic and wild birds as well as cattle. In France for instance, many cases and outbreaks are reported in these animal species every year. However, underestimation is very likely at least for avifauna species where the detection of dead animals can be challenging. Knowledge about BoNTs C, D, C/D, and D/C and the diseases they cause in animals and humans is still scarce and unclear. Specifically, the potential role of animal botulism outbreaks in cattle and poultry as a source of human illness needs to be further assessed. In this narrative review, we present the current knowledge about toxinotypes C, D, C/D, and D/C in cattle and poultry with, amongst various other aspects, their epidemiological cycles. We also discuss the zoonotic potential of these toxinotypes and some possible ways of risk mitigation. An adapted and effective management of botulism outbreaks in livestock also requires a better understanding of these less common and known toxinotypes

Biodégradation de composés organophosphores à liaison P-S (VX, tetriso et demeton-S-methyl)

Non disponible / Not availableLa décontamination des matériels militaires contaminés par les armes chimiques pose problème car la majorité des solutions décontaminantes chimiques utilisées actuellement sont corrosives et dégradent de nombreux supports. La décontamination par voie enzymatique est une alternative respectueuse de l'intégrité des matériaux mais les enzymes disponibles ne permettent de détruire qu'une famille d'agents de guerre : les agents organophosphorés de type G (soman, sarin et tabun), ce qui limite son utilisation. L'objectif de ce travail est d'isoler une enzyme capable de dégrader les agents de guerre organophosphorés de type V dont le produit type est le VX, la dégradation des agents V consistant à hydrolyser leur liaison P-S. La démarche de cette étude a consisté à rechercher des micro-organismes capables de dégrader le VX lors de leur culture, puis à identifier le micro-organisme le plus efficace à détruire le VX. Un micro-organisme Corynebacterium glumaticum ATCC 13745 a montré sa capacité à dégrader le VX ainsi que le déméton-S-méthyl et le tétriso. L'analyse [exposant 31]P RMN indique que la dégradation du VX et du tétriso se traduit par une rupture de la liaision P-S de ces composés alors que l'attaque du déméton-S-méthyl par la bactérie se situe au niveau de la liaison C-S. L'étude de la biodégradation du VX par Corynebacterium glumaticum montre que les vitesses de dégradation augmentent avec la concentration de tampon phosphate et d'extrait de levure du milieu de culture. Les essais effectués en parallèle sur la dégradation antibiotique du VX indiquent que le tampon phosphate favorise aussi la dégradation chimique du VX. Les essais effectués avec Corynebacterium glumaticum ont permis de localiser le système enzymatique qui hydrolyse la liaison P-S dans l'espace intra cellulaire. La purification enzymatique effectuée par chromatographie liquide a permis d'isoler un système enzymatique, appelé VXase, constitué de trois protéines dont une de poids moléculaire de l'ordre de 40kD pourrait être l'enzyme responsable de l'hydrolise de la liaison P-S. La caractérisation partielle de la VXase montre que cette enzyme possède une activité spécifique 10 fois supérieure à celle de la phosphotriestérase (OPH) seule enzyme décrite comme capable d'hydrolyser la liaison P-S. Nos résultats indiquent que la VXase n'est pas une OPH mais une nouvelle enzyme capable d'hydrolyser la liaison P-S

Biodégradation de composés organophosphores à liaison P-S (VX, tetriso et demeton-S-methyl)

NANCY1-SCD Pharmacie-Odontologie (543952101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Rho-Direct Form transposed and Residue Number Systems for Filter implementations

International audienceThis paper deals with a new approach for Infinite Impulse Response (IIR) Filter based on specific structure and arithmetic. The ρ-Direct Form II transposed, introduced by G. Li [1], is an numerically efficient structure for FIR or IIR filters. Compared to classical direct forms it uses more computations but less bits are necessary for the same precision. These properties made it well conditioned for fixed point arithmetic and its implementations are economical and numerically efficient comparing to other forms. In other hand, Residue Number Systems (RNS) offer an interest- ing parallelism where operations are made on small values. RNS are well known for improving the performances of DSP filters. We compare our RNS approach to fixed point implementations of DFII and ρ-DFIIt

Complex behaviors in a new 4D memristive hyperchaotic system without equilibrium and its microcontroller-based implementation

The construction of dynamic systems with new features has always been an interesting research topic. Since the introduction of the first memristor model, several memristive systems have been reported. This paper focuses on a new memristive hyperchaotic system without equilibrium, emerging from the extended diffusionless Lorenz equations. Its rich dynamics is demonstrated by using familiar tools. Hyperchaos, very long transient chaotic regimes, rare bursting oscillations schemes and coexistence of four attractors are noticed. A low-cost microcontroller-based implementation for digital engineering applications is presented to confirm its feasibility

Characterization of botulinum neurotoxin type A subtypes by immunocapture enrichment and liquid chromatography–tandem mass spectrometry

International audienceBotulinum neurotoxins (BoNT) are divided into seven toxinotypes based on their immunological properties and each toxinotype contains several subtypes according to their amino acid sequences. Here, we designed a mass spectrometry method able to identify BoNT/A subtypes in complex matrices including crude culture supernatants, food, and environmental samples. Peptides from BoNT light chain (L) specific to the subtypes BoNT/A1 to A3 and BoNT/A5 to A8 were identified. The method consists of an immunocapture step with antibodies specific to BoNT/A L chains followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on a triple quadrupole mass spectrometer (QqQ) in multiple reaction monitoring (MRM) mode. BoNT/A subtypes were correctly identified in culture supernatants and in tap water or orange juice samples with a limit of detection of 20 to 150 mouse lethal doses (MLD) and with a lower sensitivity in serum samples

Infinitely Many Coexisting Attractors in No-Equilibrium Chaotic System

This paper proposes a new no-equilibrium chaotic system that has the ability to yield infinitely many coexisting hidden attractors. Dynamic behaviors of the system with respect to the parameters and initial conditions are numerically studied. It shows that the system has chaotic, quasiperiodic, and periodic motions for different parameters and coexists with a large number of hidden attractors for different initial conditions. The circuit and microcontroller implementations of the system are given for illustrating its physical meaning. Also, the synchronization conditions of the system are established based on the adaptive control method

L'halieutique ou l'exploitation des ressources vivantes aquatiques : une science protéiforme

National audienceL’Association Française d’Halieutique réunit environ 200 scientifiques français de divers organismes d’enseignement supérieur et de recherche, de diverses disciplines, tous intéressés par l’halieutique (la science de la pêche, mais aussi des ressources aquatiques exploitées, des écosystèmes qui les supportent et des systèmes d’exploitation). Tous les deux ans, l’association organise un colloque scientifique de trois jours. Le dernier a eu lieu en juillet 2015 à Montpellier; l’occasion de faire un point sur les grandes tendances et les grands défis auxquels fait face la communauté. Cet article repose en grande partie sur les présentations faites au cours de ce colloque et qui sont consultables en ligne (http://association-francaise-halieutique.fr/conferences/)