Effects of Insecticide and Tolerant Alfalfa Cultivars on Potato Leafhopper (\u3cem\u3eEmpoasca fabae\u3c/em\u3e) Populations and Forage Yields in Quebec (Canada)

The potato leafhopper [PLH, Empoasca fabae (Harris)], which affects several crops including alfalfa (Medicago sativa L.), is a recurrent problem in several regions of Quebec. The objective was to evaluate alfalfa management tools in order to reduce yield losses caused by this pest. An experiment was conducted at two sites in Quebec over three field seasons to evaluate the impact of insecticide applications and the use of PLHtolerant cultivars on forage yield and PLH populations. Foliar insecticide applications in the seeding year reduced PLH populations but generally failed to impact alfalfa yields compared to untreated alfalfa. However, in one experiment at one site, applications done in the seeding year resulted in increased first-cut alfalfa yields in the post-seeding year compared to untreated alfalfa, even if PLH populations were low. Differences in yields between PLH-tolerant and PLH-susceptible cultivars were minimal in the seeding and post-seeding years regardless of the PLH population levels. However, two PLH-tolerant cultivars produced lower yields compared to other cultivars in the post-seeding year at one site. Preliminary results suggest that foliar insecticide applications could be a more effective way to reduce PLH populations than PLH-tolerant cultivars. However, more data will be required to confirm these results and determine the impact of these management tools on alfalfa yields

Agressivité du Simulium du complexe ornatum (Diptera, Simuliidae) en Catalogne (Espagne). Premiere mention

A l'heure actuelle, en Espagne, même si des Simulies sont incriminées chez l'homme, dans des lésions dues à des insectes hématophages, le lien direct entre ces piqûres et une espèce donnee de Simulie n'avait pas encore été éetabli pour ce pays. Une invasion récente (1993) de ces insectes dans la région de l'Alt Penedès, au nord-est de la province de Tarragone, permet aujourd'hui de combler cette lacune

Controle de domaines temporels

Cet article étudie des problème de contrôle optimal d'une équation parabolique linéaire, lorsque l'observation est l'ensemble des instants pour lesquels un critère de qualité (local en temps) sur l'état n'est pas vérifié

Arginine methylation of REF/ALY promotes efficient handover of mRNA to TAP/NXF1

The REF/ALY mRNA export adaptor binds TAP/NXF1 via an arginine-rich region, which overlaps with its RNA-binding domain. When TAP binds a REF:RNA complex, it triggers transfer of the RNA from REF to TAP. Here, we have examined the effects of arginine methylation on the activities of the REF protein in mRNA export. We have mapped the arginine methylation sites of REF using mass spectrometry and find that several arginines within the TAP and RNA binding domains are methylated in vivo. However, arginine methylation has no effect on the REF:TAP interaction. Instead, arginine methylation reduces the RNA-binding activity of REF in vitro and in vivo. The reduced RNA-binding activity of REF in its methylated state is essential for efficient displacement of RNA from REF by TAP in vivo. Therefore, arginine methylation fine-tunes the RNA-binding activity of REF such that the RNA–protein interaction can be readily disrupted by export factors further down the pathway

Genome-wide search for breast cancer linkage in large Icelandic non-BRCA1/2 families

Abstract Introduction: A significant proportion of high-risk breast cancer families are not explained by mutations in known genes. Recent genome-wide searches (GWS) have not revealed any single major locus reminiscent of BRCA1 and BRCA2, indicating that still unidentified genes may explain relatively few families each or interact in a way obscure to linkage analyses. This has drawn attention to possible benefits of studying populations where genetic heterogeneity might be reduced. We thus performed a GWS for linkage on nine Icelandic multiple-case non-BRCA1/2 families of desirable size for mapping highly penetrant loci. To follow up suggestive loci, an additional 13 families from other Nordic countries were genotyped for selected markers. Methods: GWS was performed using 811 microsatellite markers providing about five centiMorgan (cM) resolution. Multipoint logarithm of odds (LOD) scores were calculated using parametric and nonparametric methods. For selected markers and cases, tumour tissue was compared to normal tissue to look for allelic loss indicative of a tumour suppressor gene. Results: The three highest signals were located at chromosomes 6q, 2p and 14q. One family contributed suggestive LOD scores (LOD 2.63 to 3.03, dominant model) at all these regions, without consistent evidence of a tumour suppressor gene. Haplotypes in nine affected family members mapped the loci to 2p23.2 to p21, 6q14.2 to q23.2 and 14q21.3 to q24.3. No evidence of a highly penetrant locus was found among the remaining families. The heterogeneity LOD (HLOD) at the 6q, 2p and 14q loci in all families was 3.27, 1.66 and 1.24, respectively. The subset of 13 Nordic families showed supportive HLODs at chromosome 6q (ranging from 0.34 to 1.37 by country subset). The 2p and 14q loci overlap with regions indicated by large families in previous GWS studies of breast cancer. Conclusions: Chromosomes 2p, 6q and 14q are candidate sites for genes contributing together to high breast cancer risk. A polygenic model is supported, suggesting the joint effect of genes in contributing to breast cancer risk to be rather common in non-BRCA1/2 families. For genetic counselling it would seem important to resolve the mode of genetic interaction

Implications of the polymorphism of HLA-G on its function, regulation, evolution and disease association

The HLA-G gene displays several peculiarities that are distinct from those of classical HLA class I genes. The unique structure of the HLA-G molecule permits a restricted peptide presentation and allows the modulation of the cells of the immune system. Although polymorphic sites may potentially influence all biological functions of HLA-G, those present at the promoter and 3′ untranslated regions have been particularly studied in experimental and pathological conditions. The relatively low polymorphism observed in the MHC-G coding region both in humans and apes may represent a strong selective pressure for invariance, whereas, in regulatory regions several lines of evidence support the role of balancing selection. Since HLA-G has immunomodulatory properties, the understanding of gene regulation and the role of polymorphic sites on gene function may permit an individualized approach for the future use of HLA-G for therapeutic purposes