59 research outputs found
Acoustodynamometry : An innovating non-invasive technique used to measure tendon load during movement
A novel technique was developed to measure the tendon load in people and in horses in motion. This
non-invasive technique is based on a relation, demonstrated experimentally in vitro on isolated tendons
and limbs, between the velocity of ultrasound in the tendon and the load to which it is subjected.
A prototype was created to examine the equine superficial digital flexor tendon. The reproducibility
of these measurements assessed in five horses was very good in a given subject, but marked
differences were observed between the animals, in terms of plot shape and ultrasound velocity. These
differences appeared directly related to the horseâs digital standing conformation. The technique thus
validated was then used to examine the effect of four types of orthopaedic shoes compared to a standard
shoe, on hard as well as soft ground.Un procédé original de mesure
de la force qui s'exerce dans un tendon, chez le Cheval ou l'Homme en mouvement, a été mis
au point. Cette technique non-invasive repose sur une relation, démontrée expérimentalement
in vitro, sur tendons et membres isolés, entre la vitesse des ultrasons dans un tendon et la
force qui s'applique sur celui-ci. Un prototype adapté au tendon fléchisseur superficiel du
doigt du cheval a été réalisé. La reproductibilité des mesures, évaluée chez cinq chevaux,
au pas et au trot, est trĂšs bonne chez un mĂȘme individu, mais il existe des diffĂ©rences
nettes entre sujets, à la fois dans la forme des tracés et dans les niveaux de vitesse des
ultrasons observés. Ces différences sont apparues étroitement liées à l'aplomb digital des
chevaux. Le procédé ainsi validé a permis d'évaluer l'effet de quatre types de ferrures
correctrices, comparées à un fer standard, sur sol dur et sur sol meuble
COMPARISON OF TWO PREPARATION PROCEDURES (HARROWING VS. ROLLING) APPLIED TO AN EQUESTRIAN SPORT ARENA: EFFECTS ON THE DYNAMIC VARIABLES IN 3 HORSES LANDING AFTER A JUMP
The purpose of this study was to compare the dynamic variables recorded on 3 horses landing after a jump on an arena surface (sand & fibre mix) after application of two classical preparation procedures: harrowing and rolling. Each horse, equipped with a dynamometric horseshoe and an accelerometer on its right forehoof, performed 6 jumps alternatively on each prepared surface, landing alternatively at right and left lead. The maximal vertical deceleration and the energy of vibrations (>50Hz) at impact significantly decreased with harrowing, on both limbs. The braking force and braking loading rate were greater on the rolled surface but only in the leading limb. The vertical loading rate and, in the leading limb only, the maximal vertical force, were significantly larger on the rolled surface, which suggests that preparation affected the surface deeper than expected
The Yin-Yang of the Green Fluorescent Protein:Impact on Saccharomyces cerevisiae stress resistance
International audienceAlthough fluorescent proteins are widely used as biomarkers (Yin), no study focuses on their influence on the microbial stress response. Here, the Green Fluorescent Protein (GFP) was fused to two proteins of interest in Saccharomyces cerevisiae. Pab1p and Sur7p, respectively involved in stress granules structure and in Can1 membrane domains. These were chosen since questions remain regarding the understanding of the behavior of S. cerevisiae facing different heat kinetics or oxidative stresses. The main results showed that Pab1p-GFP fluorescent mutant displayed a higher resistance than that of the wild type under a heat shock. Moreover, fluorescent mutants exposed to oxidative stresses displayed changes in the cultivability compared to the wild type strain. In silico approaches showed that the presence of the GFP did not influence the structure and so the functionality of the tagged proteins meaning that changes in yeast resistance were certainly related to GFP ROS-scavenging ability (Yang)
The Sequisol project: biomechanical eval uation of the effects of equestrian track surfaces on the equine locomotor system
The quality of ground surfaces conditions equine locomotion and can be a risk factor for osteoarticular
and tendinous lesions. A novel protocol of biomechanical measurements has been developed to characterize
the effects of ground surfaces on the locomotor system and locomotion of harnessed trotter horses
under training conditions. This protocol is based on the simultaneous use of a 3D dynamometric horseshoe,
a 3D accelerometer, a superficial digital flexor (SDF) tendon force ultrasonic sensor, inertial measurement
units, and a high-speed camera. Three French trotters were used to compare two tracks at the
Grosbois training centre (crushed sand and all-weather waxed track) ; biomechanical measurements
were performed at a standardized speed (9.7 m/s, i.e. 35 km/h). The all-weather waxed track appeared as
the most damping (shock absorbing), i.e. lesser impact deceleration and braking force and lesser maximal
loading rate of the SDF tendon. However, the horseâs locomotor comfort (determined by the stride length)
did not seem to be greater. The preliminary results of the tests performed since October 2006 as part of
the Sequisol project (10 tracks tested on 5 different sites) confirm superior shock-absorbing properties as
well as a âslowerâ characteristic during the braking phase for the all-weather waxed tracks, and generally
speaking, the strong influence of maintenance conditions of the surfaces on the biomechanical results.La qualité du sol conditionne
la locomotion d'un cheval, et peut aussi ĂȘtre un facteur de risque de lĂ©sions
ostéo-articulaires et tendineuses. Un protocole original de mesures biomécaniques a été mis
au point afin de caractériser l'effet des sols sur l'appareil locomoteur et la locomotion,
chez le trotteur attelé, dans les conditions de l'entraßnement. Ce protocole repose sur
l'utilisation simultanée d'un fer dynamométrique 3D, d'un accéléromÚtre 3D, d'un capteur
ultrasonore de force dans le tendon fléchisseur superficiel du doigt (perforé), de centrales
de mesure inertielle et d'une caméra haute fréquence. Trois chevaux trotteurs français ont
été utilisés pour comparer deux pistes du centre d'entraßnement de Grosbois (sable concassé
et sable fibré-huilé); les mesures biomécaniques ont été effectuées à vitesse standardisée
(9,7 m/s, soit 35 km/h). La piste en fibré-huilé présente des propriétés d'amortissement
plus importantes que la piste en sable concassé: la décélération à l'impact, la force de
freinage et la vitesse de mise en tension maximale du tendon perforé sont plus faibles. En
revanche, le confort locomoteur du cheval, apprécié notamment par la longueur de la foulée,
n'est pas supérieur. Le bilan préliminaire des tests réalisés depuis octobre 2006 dans le
cadre du projet Sequisol (dix pistes testées sur cinq sites différents) confirme le
caractÚre plus amortissant mais aussi plus « lent », lors du freinage, des pistes en
fibré-huilé et, plus généralement, l'influence forte des conditions d'entretien des sols sur
les résultats biomécaniques
Implication de lâappareil de Golgi et de lâubiquitination dans lâactivation de TBK1 aprĂšs dĂ©tection des ARNs viraux
Type-I interferons (IFN-α/ÎČ) production and release is a major event in innate antiviral immunity. IFN production depends on the interaction between viral structures and their corresponding cellular sensors. RIG-I-Like Receptors (RLRs) and Toll-Like Receptor 3 (TLR3) sense dsRNAs in the cytosol and endosomes respectively. Stimulation of these receptors by their ligands promotes a signal transduction leading to the activation of the transcription factors NF-ÎșB and IRF3, and consequently to the production of proinflammatory cytokines and Type I Interferons (IFN-I). TBK1 (TANK-Binding Kinase 1), plays a crucial role in antiviral innate immunity, by phosphorylating the transcription factor IRF3, required for the production of type I IFNs. Although many studies have shown the critical role of this kinase in antiviral signaling, the molecular mechanism of its activation are largely unknown. We report here the localization of the ubiquitinated and phosphorylated active form of TBK1 to the Golgi apparatus after the stimulation of RLRs or TLR3, due to TBK1 ubiquitination on lysine residues 30 and 401. The ubiquitin-binding protein optineurin (OPTN) recruits ubiquitinated TBK1 to the Golgi apparatus, leading to the formation of complexes in which TBK1 is activated by trans-autophosphorylation. We also found that a viral protein binds OPTN at the Golgi apparatus, neutralizing its activity and thereby decreasing TBK1 activation and downstream signaling.LâimmunitĂ© innĂ©e antivirale repose en grande partie sur la production des interfĂ©rons de type I (IFN-α/ÎČ) par les cellules infectĂ©es et les cellules immunitaires. Cette synthĂšse rĂ©sulte de la reconnaissance de motifs viraux caractĂ©ristiques par des rĂ©cepteurs cellulaires, parmi lesquels les RIG-I-Like RĂ©cepteurs (RLR) et le Toll-Like RĂ©cepteur 3 (TLR3) dĂ©tectent lâARN viral respectivement au niveau du cytosol et des endosomes. La signalisation induite par les RLRs et TLR3 conduit Ă lâactivation dâIRF3 et de NF-ÎșB, deux facteurs de transcription impliquĂ©s respectivement dans la production dâIFN-α/ÎČ et de cytokines pro-inflammatoires. TBK1 (TANK-Binding Kinase 1) joue un rĂŽle essentiel dans lâimmunitĂ© innĂ©e antivirale, de par la phosphorylation du facteur de transcription IRF3, nĂ©cessaire Ă la production des IFNs de type I. Bien que de nombreuses Ă©tudes aient montrĂ© le rĂŽle crucial de cette kinase dans la signalisation antivirale, le processus entrainant son activation est encore mal dĂ©terminĂ© Ă ce jour. Lors de cette Ă©tude nous avons dĂ©montrĂ© que suite Ă la stimulation du TLR3 et des RLRs, la forme active, ubiquitinylĂ©e et phosphorylĂ©e, de TBK1 se relocalise au niveau de lâappareil de golgi, grĂące Ă son ubiquitination sur les rĂ©sidus K30 et K401. Ce mĂ©canisme implique la reconnaissance des chaines dâubiquitines associĂ©es Ă TBK1 par lâOptineurine (OPTN), permettant la formation dâun complexe autorisant le rapprochement des molĂ©cules de TBK1 puis la trans-autophosphorylation au niveau de lâappareil de Golgi. Au cours de ce travail nous avons Ă©galement dĂ©couvert quâOPTN est la cible dâune protĂ©ine virale, la protĂ©ine NS3 du BTV (Bluetongue Virus), qui neutralise son activitĂ© et diminue ainsi lâactivation de TBK1 et la signalisation responsable de la sĂ©crĂ©tion de cytokines antivirales
The Role of Optineurin in Antiviral Type I Interferon Production
After a viral infection and the stimulation of some pattern-recognition receptors as the toll-like receptor 3 in the endosomes or the RIG-I-like receptors in the cytosol, activation of the IKK-related kinase TBK1 leads to the production of type I interferons (IFNs) after phosphorylation of the transcription factors IRF3 and IRF7. Recent findings indicate an involvement of K63-linked polyubiquitination and of the Golgi-localized protein optineurin (OPTN) in the activation of this crucial kinase involved in innate antiviral immunity. This review summarizes the sensing of viruses and the signaling leading to type I IFN production following TBK1 activation through its ubiquitination and the sensing of ubiquitin chains by OPTN at the Golgi apparatus
The VP3 Protein of Bluetongue Virus Associates with the MAVS Complex and Interferes with the RIG-I-Signaling Pathway
Bluetongue virus (BTV), an arbovirus transmitted by Culicoides biting midges, is a major concern of wild and domestic ruminants. While BTV induces type I interferon (alpha/beta interferon [IFN-α/ÎČ]) production in infected cells, several reports have described evasion strategies elaborated by this virus to dampen this intrinsic, innate response. In the present study, we suggest that BTV VP3 is a new viral antagonist of the IFN-ÎČ synthesis. Indeed, using split luciferase and coprecipitation assays, we report an interaction between VP3 and both the mitochondrial adapter protein MAVS and the IRF3-kinase IKKΔ. Overall, this study describes a putative role for the BTV structural protein VP3 in the control of the antiviral response
Involvement of Golgi apparatus and ubiquitination in TBK1 activation after viral RNAs detection
LâimmunitĂ© innĂ©e antivirale repose en grande partie sur la production des interfĂ©rons de type I (IFN-α/ÎČ) par les cellules infectĂ©es et les cellules immunitaires. Cette synthĂšse rĂ©sulte de la reconnaissance de motifs viraux caractĂ©ristiques par des rĂ©cepteurs cellulaires, parmi lesquels les RIG-I-Like RĂ©cepteurs (RLR) et le Toll-Like RĂ©cepteur 3 (TLR3) dĂ©tectent lâARN viral respectivement au niveau du cytosol et des endosomes. La signalisation induite par les RLRs et TLR3 conduit Ă lâactivation dâIRF3 et de NF-ÎșB, deux facteurs de transcription impliquĂ©s respectivement dans la production dâIFN-α/ÎČ et de cytokines pro-inflammatoires. TBK1 (TANK-Binding Kinase 1) joue un rĂŽle essentiel dans lâimmunitĂ© innĂ©e antivirale, de par la phosphorylation du facteur de transcription IRF3, nĂ©cessaire Ă la production des IFNs de type I. Bien que de nombreuses Ă©tudes aient montrĂ© le rĂŽle crucial de cette kinase dans la signalisation antivirale, le processus entrainant son activation est encore mal dĂ©terminĂ© Ă ce jour. Lors de cette Ă©tude nous avons dĂ©montrĂ© que suite Ă la stimulation du TLR3 et des RLRs, la forme active, ubiquitinylĂ©e et phosphorylĂ©e, de TBK1 se relocalise au niveau de lâappareil de golgi, grĂące Ă son ubiquitination sur les rĂ©sidus K30 et K401. Ce mĂ©canisme implique la reconnaissance des chaines dâubiquitines associĂ©es Ă TBK1 par lâOptineurine (OPTN), permettant la formation dâun complexe autorisant le rapprochement des molĂ©cules de TBK1 puis la trans-autophosphorylation au niveau de lâappareil de Golgi. Au cours de ce travail nous avons Ă©galement dĂ©couvert quâOPTN est la cible dâune protĂ©ine virale, la protĂ©ine NS3 du BTV (Bluetongue Virus), qui neutralise son activitĂ© et diminue ainsi lâactivation de TBK1 et la signalisation responsable de la sĂ©crĂ©tion de cytokines antivirales.Type-I interferons (IFN-α/ÎČ) production and release is a major event in innate antiviral immunity. IFN production depends on the interaction between viral structures and their corresponding cellular sensors. RIG-I-Like Receptors (RLRs) and Toll-Like Receptor 3 (TLR3) sense dsRNAs in the cytosol and endosomes respectively. Stimulation of these receptors by their ligands promotes a signal transduction leading to the activation of the transcription factors NF-ÎșB and IRF3, and consequently to the production of proinflammatory cytokines and Type I Interferons (IFN-I). TBK1 (TANK-Binding Kinase 1), plays a crucial role in antiviral innate immunity, by phosphorylating the transcription factor IRF3, required for the production of type I IFNs. Although many studies have shown the critical role of this kinase in antiviral signaling, the molecular mechanism of its activation are largely unknown. We report here the localization of the ubiquitinated and phosphorylated active form of TBK1 to the Golgi apparatus after the stimulation of RLRs or TLR3, due to TBK1 ubiquitination on lysine residues 30 and 401. The ubiquitin-binding protein optineurin (OPTN) recruits ubiquitinated TBK1 to the Golgi apparatus, leading to the formation of complexes in which TBK1 is activated by trans-autophosphorylation. We also found that a viral protein binds OPTN at the Golgi apparatus, neutralizing its activity and thereby decreasing TBK1 activation and downstream signaling
The role of optineurin in antiviral type I interferon production
After a viral infection and the stimulation of some pattern-recognition receptors as the toll-like receptor 3 in the endosomes or the RIG-I-like receptors in the cytosol, activation of the IKK-related kinase TBK1 leads to the production of type I interferons (IFNs) after phosphorylation of the transcription factors IRF3 and IRF7. Recent findings indicate an involvement of K63-linked polyubiquitination and of the Golgi-localized protein optineurin (OPTN) in the activation of this crucial kinase involved in innate antiviral immunity. This review summarizes the sensing of viruses and the signaling leading to type I IFN production following TBK1 activation through its ubiquitination and the sensing of ubiquitin chains by OPTN at the Golgi apparatus
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