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We compute the Morse index of 1 -spike solutions of the semilinear elliptic problem (P p) { − Δ u = u p in Ω u = 0 on ∂ Ω u > 0 in Ω where Ω ⊂ R 2 is a smooth bounded domain and p > 1 is sufficiently large. When Ω is convex, our result, combined with the characterization in [21] , a result in [40] and with recent uniform estimates in [37] , gives the uniqueness of the solution to (P p) , for p large. This proves, in dimension two and for p large, a longstanding conjecture. [ABSTRACT FROM AUTHOR]

Abstract Genetic engineering is becoming a useful tool in the improvement of plants but concern has been expressed about the potential environmental risks of releasing genetically modified (GM) organisms into the environment. Attention has focused on pollen dispersal as a major issue in the risk assessment of transgenic crop plants. In this study, pollen-mediated dispersal of transgenes via cross-fertilization was examined. Plants of Lotus corniculatus L. transformed with either the Escherichia coli asparagine synthetase gene asn A or the β-glucuronidase gene uid A, were used as the pollen donor. Nontransgenic plants belonging to the species L. corniculatus L., L. tenuis Waldst. and Kit. ex Willd, and L. pedunculatus Cav., were utilized as recipients. Two experimental fields were established in two areas of central Italy. Plants carrying the uid A gene were partially sterile, therefore only the asn A gene was used as a tracer marker. No transgene flow between L. corniculatus transformants and the nontransgenic L. tenuis and L. pedunculatus plants was detected. As regards nontransgenic L. corniculatus plants, in one location flow of asn A transgene was detected up to 18 m from the 1.8 m2 donor plot. In the other location, pollen dispersal occurred up to 120 m from the 14 m2 pollinating plot. [ABSTRACT FROM AUTHOR]

The role that the constituents of the ascorbate-glutathione cycle play in the mechanism of contrasting ozone sensitivities was examined in mature and old tobacco leaves after acute ozone-fumigation (150 p.p.b., 5 h). Levels of the enzyme activities associated with the detoxifying system were lower in ozone-sensitive Bel W3 control plants than in unfumigated ozone-tolerant Bel B plants. In particular, the endogenous activities of ascorbate peroxidase (APX) and glutathione reductase (GR), and the metabolites ascorbic acid (AA) and reduced glutathione (GSH) were more abundant in Bel B than Bel W3 control plants. These results suggest that the higher tolerance of Bel B to O[sub 3] is associated with a greater initial content of the antioxidant enzymes or metabolites. Only in the mature leaves of the ozone-tolerant Bel B cv. did fumigation trigger activation of APX and, weakly, of dehydroascorbate reductase (DHAR). The activity of these enzymes was significantly lower after ozone treatment in both mature and old leaves of Bel W3 than in control plants. Fumigation had little effect on the ascorbate content. Its main effects on the glutathione pool were that it boosted the oxidized form and lowered the reduced form, particularly in mature Bel W3 leaves. Extractable GR activity remained unchanged in both Bel B and Bel W3 immediately after fumigation, but increased slightly 24 h later, particularly in mature leaves of Bel W3. Exposure to O[sub 3] caused a sharp decline in chloroplastic GR mRNA levels in both cultivars. However, as Western blot analysis failed to detect any major changes in GR protein content at this time, the protein must be highly stable. There is therefore a good correlation between tolerance to O[sub 3] and high endogenous levels of antioxidant metaholites such as AA and GSH in tobacco. In addition, the degree of inducibility of the system discriminates the two cultivars investigated. [ABSTRACT FROM AUTHOR]

Abstract Background Classical Swine Fever (CSFV) is one of the most important viral infectious diseases affecting wild boars and domestic pigs. The etiological agent of the disease is the CSF virus, a single stranded RNA virus belonging to the family Flaviviridae. All preventive measures in domestic pigs have been focused in interrupting the chain of infection and in avoiding the spread of CSFV within wild boars as well as interrupting transmission from wild boars to domestic pigs. The use of plant based vaccine against CSFV would be advantageous as plant organs can be distributed without the need of particular treatments such as refrigeration and therefore large areas, populated by wild animals, could be easily covered. Results We report the in planta production of peptides of the classical swine fever (CSF) E2 glycoprotein fused to the coat protein of potato virus X. RT-PCR studies demonstrated that the peptide encoding sequences are correctly retained in the PVX construct after three sequential passage in Nicotiana benthamiana plants. Sequence analysis of RT-PCR products confirmed that the epitope coding sequences are replicated with high fidelity during PVX infection. Partially purified virions were able to induce an immune response in rabbits. Conclusion Previous reports have demonstrated that E2 synthetic peptides can efficiently induce an immunoprotective response in immunogenized animals. In this work we have showed that E2 peptides can be expressed in planta by using a modified PVX vector. These results are particularly promising for designing strategies for disease containment in areas inhabited by wild boars.