Two Tobravirus expression vectors were evaluated for the use as a rapid screening method for anti-nutritional proteins against plant pathogens. Accumulation of green fluorescent protein (GFP) and snowdrop lectin gene (Galanthus nivalis agglutinin, LECGNA2, M55556) in Nicotiana benthamiana by Tobacco rattle virus expression vectors was characterized. Virally expressed proteins were detected in leaves (3-14 days post-inoculatiion) and roots (6-24 dpi) by UV (GFP), western blotting and tissue printing. 25 -50 ng of GNA was detected in root extracts. Cross protection was induced by TRV-GFP. Foreign genes inserted in place of TRV RNA2 non-structural genes (2b and 2c) were stably maintained over serial passages. But recombination at remaining 'cross-over' sites may occur. 2D iso-electricfocusing detected a 50-kDa GNA molecule in root and leaf extract. GNA did not confer resistance to root-knot nematodes, although gall by root-knot nematodes (mixed Meloidogyne spp. and M.javanica Crete line 17) were significantly reduced by 22% in roots infected by TRV-GNA (3.83 sqrt galls and 4.5 sqrt galls respectively) compared to virus-free roots treatment (4.94 sqrt galls, sed 0.398; p<.025 and 5.273 sqrt galls, sed 0.2403; <.003 respectively). Effects of GNA on Aulacorthum solani was delayed to the second nymph generation (N2). Mean N2 weights feeding on TRV-GNA (0.246 mg ±0.0159; p <05) and TRV-fsGNA (0.212 mg ±0.018; p<.001) infected plants were significantly smaller by 15.2% and 26.6% respectively, compared to virus-free treatments (0.290 mg ±0.014). Similar trends were detected for total nymph weights. Low toxicity was related to high quality phloem and ingestion of smaller volumes for normal development (i.e. concentration effect). Decrease in gall by the mixed Meloidogyne population and an unexpected toxicity to A solani indicated that truncated GNA was a protein with merolectin properties. The viability of this system as a rapid 'm planta' expression system is discussed.

Tobacco rattle virus (TRV) is a bipartite plant virus that infects potato tubers to produce the spraing or corky ring spot (CRS) disease of potato. TRV is primarily a soil-borne pathogen that is vectored by trichodorid nematodes. Spraing is characterized by the production of brown arcs and flecks in the tuber flesh or circular rings on its external surface. Spraing has been described as a hypersensitive response (HR). However, the genetic and biochemical nature of spraing had not been previously investigated experimentally. I have conducted studies to reveal the gene expression and the biochemical basis for spraing formation. Microarray analysis of RNA extracted from tuber-tissue showing spraing symptoms, revealed up-regulation of several defence related genes. Quantitative RT-PCR (qRT-PCR) of some of the differentially-expressed potato defence related genes was done for verification of the microarray data. Biochemical tests for cell death response reactions and staining for HR-related compounds or production of reactive oxygen species (ROS) also revealed the operation of HR-related processes in the spraing-affected tuber. Uneven distribution of the TRV RNA-1 in a spraing-symptomatic tuber also supports the notion that it’s a virus-induced HR-response. RNA-2 of TRV besides coding for the CP also carries the non-structural genes, 2b and 2c genes that are responsible for the nematode transmission of TRV. Fifteen different TRV recombinant isolates were prepared and the influence of the RNA-2 specific genes, encoded by a range of TRV-isolates, in causing infection among different cultivars of potato was also evaluated. Investigations were conducted to identify TRV-susceptible genotypes in which virus could move systemically and accumulate to a sufficient level to be useful for TRV-infection and VIGS-related studies for functional analysis of potato genes.

No description available.

No description available.

SANTRAUKA Potato mop-top virus, priklausantis Pomovirus genčiai ir Tobacco rattle virus, priklausantis Tobravirus genčiai – tai dirvožemiu plintantys virusai. Tai patogenai, kurie plačiai paplitę pasaulyje. Pastaruoju metu vis labiau susidomėta šiais virusais, mat jie sukelia daug žalos daugeliui augalų, tame tarpe ir labai svarbių kultūrinių augalų. Su šiais patogenais kovoti yra labai sudėtinga, taigi iškyla labai rimta problema, kurią bandoma išspręsti. Todėl šiame darbe ir buvo siekiama susipažinti su šiais virusais, jų pernešėjais bei padaryti pirmuosius žingsnius, ieškant būdus kovai su šais patogenais. PMTV – tai patogenas, kuriam nebūdingas gausus šeimininkų ratas. Jis infekuoja tik nedaugelį augalų rūšių. Tai viena iš savybių, kuria skiriasi nuo TRV. Pastarasis priešingai, pasižymi didele augalų-šeimininkų gausa. Šie virusai labai panašūs tuom, kad daugelyje augalų jie sukelia panašius simptomus bei pažeidimus. Net indikatoriniuose augaluose jų sukeltos žaizdos yra labai panašios. Taigi, susiduriama su problema, mat identifikuoti juos vizualiai yra labai sudėtinga. Tik N. benthamiana indikatorinis augalas gali padėti atskirti šiuos virusus: PMTV jame sukelia sisteminę reakciją, sisteminė mozaika išplinta po visą augalą, o TRV sukelia tik vietines žaizdas. Šiame baigiamajame darbe buvo siekiama identifikuoti PMTV bei TRV molekuliniais metodais. Identifikacijoje buvo pritaikytas imunofermentinis metodas – ELISA. Buvo nustatyta, kad šis metodas labiau tinka... [toliau žr. visą tekstą] / SUMMARY Potato mop-top virus (genus Pomovirus) and Tobacco rattle virus (genus Tobravirus) – soil born viruses. These pathogenes are distributed worldwide and can significantly reduce the quality and yield of potato and other horticultural plants. So in recent years more and more people are interesting in these viruses. These viruses are responsible for economic losses in potato crops. To control the spread of viruses is vary difficult, so nowadays it is a serious problem, which everybody wants to solve it. Virus control depends on vector management, so the main purpose of this article was to know more about these viruses and thier vectors and to do first steps to finding ways of viruses’ suitable control measures. PMTV has narrow range of hosts. On the contrary TRV has a very wide natural host range. So it is one of the differences from these soil borne viruses. However diagnosis is further complicated by the fact that TRV and PMTV are very similar viruses, even they can cause similar symptoms to indicator plants. So to diagnose reliable these viruses by visual symptoms are very difficult. Just in indicator plant N. benthamiana these soil borne viruses cause different symptoms: PMTV cause sistemical reaction, sistemical mosaic spreads in whole plant and TRV cause local lessions. PMTV and TRV were identificated with different molecular methods. These viruses were detected by enzyme-linked immunosorbent assay. DAS-ELISA was shown to be more sensetive and reliable method for... [to full text]

L’objectif de cette étude est de caractériser le bruit de graillonnement des boîtes de vitesses automobiles, qui résulte des chocs entre les pignons au niveau des rapports non engagés, sous l’effet des fluctuations de vitesses imposées par le moteur. Outre les paramètres de conception de la boîte de vitesses et les conditions de fonctionnement, les paramètres qui gouvernent la réponse dynamique des pignons fous sont les couples de traînée et les caractéristiques des contacts qui gouvernent les chocs entre dents. Un modèle numérique non linéaire a été élaboré pour caractériser la réponse dynamique d’un pignon fou. Il permet d’identifier le seuil d’excitation au-delà duquel le phénomène de graillonnement apparaît et de qualifier la très grande diversité de comportements dynamiques susceptibles d’être observés, en fonction du niveau d’excitation adimensionnée, du jeu de denture et du coefficient de restitution des chocs entre dents. Les paramètres inconnus ont été identifiés expérimentalement, grâce à l’exploitation d’un banc d’acyclisme et l’implémentation de codeurs optiques sur les pignons menant et fou. Des essais en réponse libre amortie ont permis de discriminer les différentes sources de dissipation(roulements, palier du pignon fou, barbotage, etc.) et de valider les modèles permettant d’identifier le couple de traînée s’exerçant sur chaque pignon fou. D’autres essais en régime de fonctionnement stationnaire ont permis de décrire le coefficient de restitution des chocs entre les pignons, sa dispersion et sa variation avec la vitesse d’impact. Les mesures effectuées sous une excitation maîtrisée ont permis de caractériser le comportement dynamique du pignon fou et de valider les hypothèses retenues et les résultats numériques obtenus par le modèle non linéaire, recalé à partir des paramètres préalablement identifiés. Enfin, l’analyse du transfert entre les impulsions générées au niveau des pignons et la réponse vibratoire du carter a permis d’évaluer expérimentalement et numériquement le critère qui qualifie le bruit de graillonnement rayonné par la boîte de vitesses. La mise en oeuvre du modèle numérique permet d’analyser l’influence des paramètres de conception de la boîte de vitesses et de proposer des solutions qui minimisent le graillonnement, pour l’ensemble des rapports de la boîte et des conditions de fonctionnement. / The aim of this work is to characterize the rattle noise of automotive gearboxes, resulting from impacts between toothed wheels of unselected gear ratios. Dynamic response of idle gears firstly depends on design parameters and engine operating conditions. The unknown parameters are the drag torque acting on the idle gear and characteristics of impacts between teeth.A non linear dynamic model has been developed in order to identify dynamic response of idle gears. It allows identification of excitation threshold beyond which rattle noise rises, and describes the wide variety of dynamic behaviors that are likely to appear, depending on the dimensionless excitation amplitude, the clearance between gears and the restitution coefficient of impacts between teeth. The unknown parameters have been identified experimentally through implementation of optical encoders in the gearbox and the operation of a specific acyclism test bench. Analysis of the free damped response of the gearbox allowed discrimination of the different dissipation sources (bearings, connection between idle gear and shaft, churning, etc.). Models proposed to identify the drag torque have been validated. Further tests under stationary operating conditions allowed measurement of the restitution coefficient of impacts and its velocity dependent probability density function. Experiments under controlled excitation were used to characterize the dynamic behavior of the idle gear and validate the assumptions and the numerical results obtained from the non linear dynamic model, fitted with the parameters previously identified. Finally, the transfer between the impulses generated at the gears and the housing vibration has been investigated to evaluate experimentally and numerically the criterion used to describe the rattle noise radiated from the gearbox. The implementation of the model allows analysis of the influence of the gearbox design parameters and solutions that minimize rattle noise can be proposed for all gear ratios and operating conditions of the gearbox.

This thesis is concerned with a problem in the interpretation of non-western art: the iconography of the raven rattle, a carved ritual object of widespread distribution on the Northwest Coast of North America. Iconographic analysis (after Panofsky) involves identifying cultural themes and concepts associated with artistic motifs. Because of the relative scarcity of recorded primary sources of interpretation, the method adopted in this analysis has been to infer meanings from relevant cultural contexts and data. Relevant data have been judged to be museum notes, ethnographies, and myths and relevant contexts, the ceremonies in which the rattle was used. The problem has been to identify the individual motifs appearing on the rattle with associated themes and concepts, and, because the rattle is a complex image, to interpret their interrelationship within the context in which the rattle was used: initiation ceremonies presided over by chiefs. For the dominant motifs on the rattle I have argued the following interpretations: 1. The "reclining figure motif" on the back of the rattle represents the guardian spirit quest, in which the reclining figure is the novice, the protruding tongue stands for the passage of power, and the animal at the other end of the tongue identifies the source of power. 2. The "raven" at the head of the rattle refers to the origin of daylight, an event of key significance in Northwest Coast cosmology. 3. The creature on the belly of the rattle represents a trapped, wealth-bringing, supernatural, sea monster. These interpretations subsume the more specific identifications that have been made by ethnographers and informants of the objects on the rattle. Within the context in which the raven rattle was used, I have suggested that the interpretations relate to each other as follows: the origin of daylight marks the beginning of the social and natural order, of the guardian spirit quest, and of reciprocity. The sea monster on the belly is a symbol of controlled supernatural power and wealth — or the fruits of the successful quest. The relationship of these associations to the chiefs who used the rattle, is that the chief was both wealth-bringer to his tribe and had access to the "controlled use of supernatural power. This he exerted on behalf of the social order in initiation ceremonies. These conclusions indicate that the raven rattle was a significantly general symbol whose thematic referents were assumptions basic to Northwest Coast culture. In reaching these conclusions, the utility of the iconographic approach, as adapted and applied to an analysis of images in Northwest Coast art, has been demonstrated. / Arts, Faculty of / Anthropology, Department of / Graduate

Résumé : Pour se propager dans les cellules de son hôte et évader les réponses immunitaires, les virus végétaux ont développé plusieurs stratégies de défense. Ici, nous avons investigué les structures génétiques du Apple stem pitting virus (ASPV). Nous avons aussi étudié la diversité moléculaire des isolats d’ASPV provenant des poires en regardant les séquences des gènes CP et TGB afin de mieux comprendre les mécanismes évolutionnaires utilisés par ASPV. Nos études ont démontré que les mutations, incluant les insertions et les délétions, la sélection purificatrice et la recombinaison furent des facteurs importants dans l’évolution du l’ASPV en Chine et possiblement mondialement. Comme tous les virus végétaux, l’ASPV se défend contre le RNA silencing de l’hôte grâce à un suppresseur de RNA silencing (VSR) et nous avons montré que le VSR de l’ASPV est la protéine de capside (CP) du virus. Nous avons aussi établi que la diversité moléculaire cause non seulement une variété de symptômes chez son hôte, Nicotiana occidentalis. Cependant elle cause aussi de la variabilité antigénique chez différents isolats, ce qui mène à des écarts de réactivité sérologique entre isolats. Les plantes ont développé plusieurs stratégies pour se défendre contre les virus. Ici, nous avons étudié comment la plante Arabidopsis se défend contre le Tobacco rattle virus (TRV) via le RNA silencing. Nous avons constaté que les phénomènes de susceptibilité, récupération et virus induced gene silencing (VIGS) sont des mécanismes séparables. Nous avons démontré que les protéines AGO2 et AGO4 sont nécessaires à la susceptibilité initiale au TRV, tandis qu’AGO1 est importante pour les VIGS, tandis que la récupération est médiée par d’autres acteurs qui n’ont pas encore été identifiés. Nos résultats suggèrent l’existence de complexes distincts ciblant différentes populations d’ARN viral et cellulaire. De plus, nous avons montré que la répression de la traduction est un mécanisme important durant la récupération de la plante suite à une infection virale, et que les complexes de décoiffage et de RNA processing jouent des rôles importants dans la dégradation des ARNs viraux. Finalement, nous avons montré que les plantes ayant une mutation dans le gène DCP2 présentent un niveaux de VIGS accrue, ainsi qu’une augmentation des niveaux d’ARN viral. Puisque DCP2 fait partie des complexes de décoiffage qui se trouvent dans des granules spécialisés nommés processing bodies (PBs), cela suggère que les PBs jouent un rôle important dans l’élimination les virus. / Abstract : To live in host cells or to escape from host immunity, plant viruses involved a series of defense strategies. Here we investigated Apple stem pitting virus (ASPV) population structures and molecular diversity of ASPV pear isolates based on its function important gene CP and TGB in China, so as to infer the evolution mechanisms of ASPV. Our study showed that mutations (including insertions or deletions), purifying selection, and recombination were important factors driving ASPV evolutions in China or maybe even in the world. And also ASPV defends against it hosts by encoding a VSR. We also showed that ASPV molecular diversity not only induced different biological properties on its herbaceous host N. occidentails but also resulted in antigenic variation of different ASPV CP isolates, which leaded to differences in serological reactivity among rCPs of different ASPV isolates. Plants have developed a series of mechanisms to defend themselves against viruses. Here we how Arabidopsis defend against. We show that virus susceptibility, recovery, and virus induced gene silencing (VIGS) appear to be separable phenomena, with AGO2 and AGO4 playing important roles in the initial susceptibility to TRV, AGO1 playing an important role in VIGS, and as yet unidentifid players mediating recovery. These results suggest the existence of distinct RNA-induced silencing complexes that target different RNA populations within the cell and over time. Furthermore, we showed that translational repression of viral RNA is likely to play an important role in virus recovery and that decapping function plays an important role in clearing viral RNA from the cell. We also showed that a decapping mutant (DCP2) displayed an increased VIGS and virus RNA accumulation, an important role for PBs in eliminating viral RNA.

Gear rattle is caused by engine torsional vibration (engine order response) imparted to the transmission components, further causing the gears to oscillate within their functional backlashes. These oscillations lead to the repetitive impact of gear teeth, which lead to noisy responses, referred to as gear rattle. The lack of in-depth research into the effect of lubricant on gear rattle has been identified as a deficiency in the previous research in rattle. The aim ofthe current work is to address this shortcoming. The thesis outlines a new approach in investigating the problem of idle gear rattle. The approach is based on the assumption that under idling condition the teeth-pair impact loads are sufficiently low and the gear speeds are sufficiently high to permit the formation of a hydrodynamic lubricant film between the mating gear teeth. This film acts as a non-linear spring-damper that couples the driver and the driven gears. A torsional single-degree of freedom model is used in the development of the theory. The model is then expanded into a seven-degree of freedom torsional model and finally into an Il-degree of freedom model that also includes the lateral vibrations of the supporting shafts. The Il-degree of freedom model is based on a real life transmission that is also used in experimental studies to validate the model. It is found that lubricant viscosity and bearing clearance (lubricant resistance in squeeze) play important roles in determining the dynamics of the system and its propensity to rattle. At low temperatures, the lateral vibrations of the shafts, carrying the gears interfere with the gear teeth impact action. The severity of rattle is determined by the relationship between the entraining and squeeze film actions of the hydrodynamic film. When the latter dominates, the system can rattle more severely. The numerical results are found to correlate well with the experimental findings obtained from vehicle tests in a semi-anechoic chamber and also with those from a transmission test rig in the powertrain laboratory.

La boite de vitesses est un des principaux organes d’une automobile et son développement est complexe. De nombreuses contraintes doivent être prises en compte et notamment son comportement acoustique et vibratoire. Cet aspect de la conception est de nos jours assez mal maitrisé et les nuisances acoustiques des boites de vitesses, telle que le bruit de grenaille, sont bien souvent découvertes tardivement. L’objectif de ces travaux était le développement d’un modèle numérique de dynamique des engrenages applicable aux boites de vitesses et permettant de prédire les conditions d’apparition du bruit de grenaille. La modélisation proposée dans cette thèse repose sur une association originale de différentes modélisations et est applicable à la grande majorité des boites de vitesses. Les éléments flexibles tels que les arbres et les carters sont modélisés par la méthode des éléments-finis. Un modèle d’engrenage basé sur le modèle de contact de Kelvin-Voigt est développé. Ce dernier permet la prise en compte des pertes de contact et des chocs sur les flancs avants et arrières. Pour compléter la modélisation, des modèles de pertes mécaniques sont implémentés afin de prendre en compte l’influence des roulements, des paliers lisses, des synchroniseurs et du barbotage des pignons dans l’huile. Le modèle développé, couplé à un indicateur de bruit de grenaille, permet de réaliser des études de sensibilités afin d’identifier les paramètres influents sur le bruit de grenaille mais aussi de comparer les comportements vibratoires de différentes configurations. Pour finir, une campagne d’essais sur une boite de vitesse industrielle est réalisée et des résultats de simulations lui sont confrontés. / The gearbox is an important component of an automobile and its development is complex. Numerous constraints must be taken into account, particularly its noise and vibration behavior. This aspect of the conception is nowadays poorly mastered and the noise pollution of gearboxes, such as the rattle noise, are often discovered late. The aim of this work was the development of a numerical model of gear dynamics adapted to gearboxes’ modelling and allowing to predict the conditions of gear rattle noise appearance. The model proposed in this thesis is based on an original combination of different models and is applicable to the vast majority of gearboxes. Flexible components, such as shafts and housings are modeled by the finite element method. A gear model based on Kelvin-Voigt contact model is developed. It allows to take into account the contact losses and the back side contacts. To complete this model, mechanical loss models are implemented in order to take into account the influence of the bearings, plain bearings, synchronizers and gears’ immersion in oil. This model coupled with a noise indicator allows for sensitivity analyzes to identify influential parameters on the rattle noise but also to compare the dynamic behavior of different configurations. Finally, a test campaign on an industrial gerbox is conducted and simulation results are confronted to measurements.