Recherche de gènes de résistance naturelle à deux viroses de la vigne: le court-noné et l'enroulement

Un grand nombre de vignes (734) représentant les différentes classes de la famille des Vitacées (Vitis américains et asiatiques, Vitis vinifera, hybrides interspécifiques) a été testé vis-à-vis de leur résistance naturelle aux virus du court-noué (GFLV et ArMV) èt de l'enroulement (GLRaV-1 et 3). L'accent a été mis sur les V. vinifera d'origine moyen-orientale du fait de la possible coévolution de la vigne et du GFLV dans ces pays. La méthode d'inoculation utilisée a été la greffe-bouture herbacée. Mais il s'est avéré que par cette technique, il était difficile de reproduire à l'identique les conditions de l'inoculation. En effet, toutes les variétés n'ont pas la même aptitude au greffage et l'état physiologique des plantes joue également un rôle important sur ce facteur. Ainsi, nous avons considéré qu'une variété était sensible si le virus avait été détecté dans au moins une de ses greffes . Ce qui a été le cas de toutes les variétés pour lesquelles le greffage avec un inoculum GFLV ou GLRaV a réussi. L'inoculation de l'ArMV est apparue plus difficile à obtenir, sans doute du fait que la vigne n'est pas un hôte principal de ce virus. Il semble qu'en fait cette méthode d'inoculation ne soit pas adaptée au but recherché. La pression d'inoculation est d'une part trop forte. D'autre part, le virus étant directement mis en contact avec les vaisseaux, la technique ne permet pas de repérer les résistances qui pourraient intervenir aux premiers stades d'une infection naturelle .Investigations on natural resistance genes for two grapevine viruses: The fanleaf degeneration and the leafroll diseaseA great number of grapevine varieties (734) belonging to the different classes of the Vitaceae family (American and Asian Vitis, Vitis vinifera, interspecific hybrids) was screened to identify sources of resistance to fanleaf degeneration (GFLV and ArMV) and to leafroll disease (GLRaV-1 and 3). Special attention was paid to Middle Eastern Vitis vinifera sources due to the possibility that GFLV and V. vinifera evolved together in the Middle East. Inoculation was by green grafting. As the inoculation conditions were difficult to control, we considered a variety to be susceptible if the virus was found in at least one graft. That was true for all varieties for which the graft with a GFLV or GLRaV inoculum had been successful. It appeared to be more difficult to inoculate ArMV, possibly because the grapevine is not the principal host of this virus. In fact, it seems that this inoculation technique is not suitable for this type of investigation. On the one hand, the inoculation pressure is too strong. On the other hand, as the virus is in direct contact with the vessels, the technique does not allow to identify resistances that might occur in the first stage of a natural infection

Comparaison de différentes techniques de greffage vis-à-vis de leur efficacité de transmission virale sur vigne

Dans le but d'effectuer un criblage rapide d'un grand nombre de variétes de vigne vis-à-vis de leur résistance aux virus, nous avons recherché quelle méthode d'inoculation était la plus adaptée . L'inoculation mécanique d'un virus à la vigne étant difficile à obtenir, nous avons comparé différentes techniques de greffage: greffage sur bois, greffage en vert avec porte-greffe préalablement enraciné ou non, chaque fois, deux positions possibles pour l'inoculum: greffon ou porte-greffe.Les résultats de cette étude indiquent que le greffage sur bois avec l'inoculum en position de porte-greffe correspond à la méthode la plus efficace. Toutefois, le greffage en vert avec porte-greffe non enraciné donne également de bons résultats, toujours avec l'inoculum en position de porte-greffe. Etant donnés les avantages que présente la greffe en vert en ce qui concerne la surface necessaire à sa réalisation et sa vitesse de réalisation, ainsi que son utilisation possible tout au long de l'année, elle paraît tout à fait adaptée pour inoculer un grand nombre de variétés. Comparison of the viral transmission efficiency of different grafting techniques on grapevinesWith the objective of screening a great number of grapevine varieties for their resistance to virus diseases, we looked for the most appropriate technique of inoculation. As the mechanical inoculation of a virus to the grapevine succeeds only under special conditions, we compared different grafting techniques: dormant grafting and green grafting, the last with and without previously rooted rootstock. For each of these three methods, the inoculum was used as the stock on one hand, as the scion on the other hand. This study proved that the dormant grafting technique using the inoculum as the rootstock is the most efficient technique. Nevertheless, good results were obtained by using the green grafting technique without previously rooting the rootstock, the inoculum being also used as the rootstock. As the green grafting method doesn't require a great area, is not time-consuming and can be performed throughout the year, it seems therefore to be a very convenient method of inoculating a great number of varieties

Rare-earth-activated glasses for solar energy conversion

The solar cells efficiency may be improved by better exploitation of the solar spectrum, making use of the down-conversion mechanism, where one high energy photon is cut into two low energy photons. The choice of the matrix is a crucial point to obtain an efficient down-conversion process with rare-earth ions. When energy transfer between rare earth ions is used to activate this process, high emission and absorption cross sections as well as low cut-off phonon energy are mandatory. In this paper we present some results concerning 70SiO2-30HfO2 glass ceramic planar waveguides co-activated by Tb3+/Yb3+ ions, fabricated by sol gel route using a top-down approach, and a bulk fluoride glass of molar composition 70ZrF4 23.5LaF3 0.5AlF3 6GaF3 co-activated by Pr3+/Yb3+ ion. Attention is focused on the assessment of the energy transfer efficiency between the two couples of rare earth ions in the different hosts

Experimental investigation of the stability of Fe-rich carbonates in the lower mantle

International audienceThe fate of carbonates in the Earth's mantle plays a key role in the geodynamical carbon cycle. Although iron is a major component of the Earth's lower mantle, the stability of Fe-bearing carbonates has rarely been studied. Here we present experimental results on the stability of Fe-rich carbonates at pressures ranging from 40 to 105 GPa and temperatures of 1450-3600 K, corresponding to depths within the Earth's lower mantle of about 1000-2400 km. Samples of iron oxides and iron-magnesium oxides were loaded into CO2 gas and laser heated in a diamond-anvil cell. The nature of crystalline run products was determined in situ by X-ray diffraction, and the recovered samples were studied by analytical transmission electron microscopy and scanning transmission X-ray microscopy. We show that Fe-(II) is systematically involved in redox reactions with CO2 yielding to Fe-(III)-bearing phases and diamonds. We also report a new Fe-(III)-bearing high-pressure phase resulting from the transformation of FeCO3 at pressures exceeding 40 GPa. The presence of both diamonds and an oxidized C-bearing phase suggests that oxidized and reduced forms of carbon might coexist in the deep mantle. Finally, the observed reactions potentially provide a new mechanism for diamond formation at great depth

NOD × 129.H2g7 Backcross Delineates 129S1/SvImJ-Derived Genomic Regions Modulating Type 1 Diabetes Development in Mice

OBJECTIVE: Introduction of genes targeted in 129/Sv embryonic stem (ES) cells into NOD mice brings about linked genes that may modulate type 1 diabetes. Our objective was to identify 129S1/SvJ non-MHC regions contributing type 1 diabetes resistance or susceptibility in backcross to NOD/LtJ. RESEARCH DESIGN AND METHODS: After congenic transfer of the NOD H2(g7) haplotype onto 129S1/Sv, 310 females were produced by NOD x (NOD x 129.H2(g7))F1 backcross (N2). A genome scan for quantitative trait locus (QTL) affecting clinical diabetes, age of diabetes onset, and insulitis severity was performed using subphenotype characteristics to improve power and resolution for detection of diabetes susceptibility loci. RESULTS: Thirty-six of 310 (11.6%) N2 females developed type 1 diabetes between 14 and 40 weeks. Significant evidence of linkage for only a single previously reported Idd complex locus (Idd10/17/18, chromosome [Chr] 3) was indicated for clinical diabetes. The quantitative traits of insulitis either alone or combined with age at type 1 diabetes onset were significantly linked to known Idd regions on Chr 1 (Idd5 region), Chr 4 (Idd9 region), Chr 8 (Idd22), Chr 11 (Idd4.3), and proximal Chr 17 (Idd16 region). Significant 129S1/Sv resistance contributions were identified on Chr 1, 15 (two loci), and 19, with suggestive evidence for additional novel 129/Sv resistance QTL on Chr 5 and 17 and susceptibility on Chr 2. CONCLUSIONS: The 129S1/SvJ genome harbors collections of both known and potentially novel non-MHC Idd loci. Investigators targeting 129/Sv genes mapping within chromosomal regions reported herein or elsewhere in the genome need to exclude potential contributions from linked Idd loci by generating a NOD.129 control strain expressing the nontargeted allele

Fe–FeO and Fe–Fe₃C melting relations at Earth's core–mantle boundary conditions: Implications for a volatile-rich or oxygen-rich core

International audienceEutectic melting temperatures in the Fe–FeO and Fe–Fe3C systems have been determined up to 150 GPa. Melting criteria include observation of a diffuse scattering signal by in situ X-Ray diffraction, and textural characterisation of recovered samples. In addition, compositions of eutectic liquids have been established by combining in situ Rietveld analyses with ex situ chemical analyses. Gathering these new results together with previous reports on Fe–S and Fe–Si systems allow us to discuss the specific effect of each light element (Si, S, O, C) on the melting properties of the outer core. Crystallization temperatures of Si-rich core compositional models are too high to be compatible with the absence of extensive mantle melting at the core–mantle boundary (CMB) and significant amounts of volatile elements such as S and/or C (>5 at%, corresponding to >2 wt%), or a large amount of O (>15 at% corresponding to ∼5 wt%) are required to reduce the crystallisation temperature of the core material below that of a peridotitic lower mantle

A Study of the Luminosity and Mass Functions of the Young IC 348 Cluster using FLAMINGOS Wide-Field Near-Infrared Images

We present wide-field near-infrared (JHK) images of the young, 2 Myr IC 348 cluster taken with FLAMINGOS. We use these new data to construct an infrared census of sources, which is sensitive enough to detect a 10 Mjup brown dwarf seen through an extinction of Av=7mag. We examine the cluster's structure and relationship to the molecular cloud and construct the cluster's K band luminosity function. Using our model luminosity function algorithm, we derive the cluster's initial mass function throughout the stellar and substellar regimes and find that the IC 348 IMF is very similar to that found for the Trapezium Cluster with both cluster IMFs having a mode between 0.2 - 0.08 Msun. In particular we find that, similar to our results for the Trapezium, brown dwarfs constitute only 1 in 4 of the sources in the IC 348 cluster. We show that a modest secondary peak forms in the substellar IC 348 KLF, corresponding to the same mass range responsible for a similar KLF peak found in the Trapezium. We interpret this KLF peak as either evidence for a corresponding secondary IMF peak at the deuterium burning limit, or as arising from a feature in the substellar mass-luminosity relation that is not predicted by current theoretical models. Lastly, we find that IC 348 displays radial variations of its sub-solar (0.5 - 0.08 Msun) IMF on a parsec scale. Whatever mechanism that is breaking the universality of the IMF on small spatial scales in IC 348 does not appear to be acting upon the brown dwarf population, whose relative size does not vary with distance from the cluster center.Comment: 53 pages, 20 figures, AASTeX5.0. Color version of Figure 1 made available in jpg format. Figure(s) 2,3,5 are reduced in resolution. Accepted 14 Jan 2003 to the Astronomical Journa

International multicentre observational study to assess the efficacy and safety of a 0·5 mg kg−1 per day starting dose of oral corticosteroids to treat bullous pemphigoid

BackgroundEuropean guidelines propose a 0 center dot 5 mg kg(-1) per day dose of oral prednisone as initial treatment for bullous pemphigoid (BP). We assessed the safety and efficacy of this regimen depending on BP extent and general condition of the patients.MethodsIn a prospective international study, we consecutively included all patients diagnosed with BP. Patients received a 0 center dot 5 mg kg(-1) per day dose of prednisone, which was then gradually tapered 15 days after disease control, with the aim of stopping prednisone or maintaining minimal treatment (0 center dot 1 mg kg(-1) per day) within 6 months after the start of treatment. The two coprimary endpoints were control of disease activity at day 21 and 1-year overall survival. Disease severity was assessed according to the Bullous Pemphigoid Disease Area Index (BPDAI) score.ResultsIn total, 198 patients were included between 2015 and 2017. The final analysis comprised 190 patients with a mean age of 80 center dot 9 (SD 9 center dot 1) years. Control of disease activity was achieved at day 21 in 119 patients [62 center dot 6%, 95% confidence interval (CI) 55 center dot 3-69.5]; 18 of 24 patients (75%, 95% CI 53 center dot 3-90 center dot 2), 75 of 110 patients (68 center dot 8%, 95% CI 59 center dot 2-77 center dot 3) and 26 of 56 patients (46.4%, 95% CI 33 center dot 0-60 center dot 3) had mild, moderate and severe BP, respectively (P = 0 center dot 0218). A total of 30 patients died during the study. The overall Kaplan-Meier 1-year survival was 82 center dot 6% (95% CI 76 center dot 3-87 center dot 4) corresponding to 90 center dot 9%, 83 center dot 0% and 80 center dot 0% rates in patients with mild, moderate and severe BP, respectively (P = 0 center dot 5). Thresholds of 49 points for BPDAI score and 70 points for Karnofsky score yielded maximal Youden index values with respect to disease control at day 21 and 1-year survival, respectively.ConclusionsA 0 center dot 5 mg kg(-1) per day dose of prednisone is a valuable therapeutic option in patients with mild or moderate BP whose general condition allows them to be autonomous.</p