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Question: Cushion-forming vascular plants are adapted to alpine environments and act as ecosystem engineers by moderating microclimate and creating a fertility island under their canopy. Most of the available studies on cushion ecology have been devoted to plant facilitation, but none used a holistic approach that considers the response of co-existing plant species with other key ecosystem players. Here, we quantified the biogenic effect and facilitation capacity of Astragalus siculus, a spiny nitrogen-fixing cushion plant, and test the hypothesis that the facilitation effect would increase with elevation as stress gradient.Location: Mount Etna, the highest active volcano in the Mediterranean Basin.Methods: We combined chemical characterization of the soil with a description of the soil microbiota by high-throughput sequencing of bacterial and eukaryotic rRNA gene markers carried out at three elevations, that is 1650, 1900 and 2210 m a.s.l. In addition, we analysed the microclimate outside and inside the Astragalus canopy to assess the linkages between above- and below-ground ecosystem compartments and quantified the occurrence of co-existing vascular plants.Results: Astragalus cushions have strong biogenic effects on above- and below-ground conditions by dramatically increasing soil organic carbon and total nitrogen stocks at 1900 and 2210 m elevation. Moreover, a buffering of soil temperature and moisture regimes was recorded, with lower temperatures in summer but higher in winter inside the cushions. Cushions harbour a specific bacterial and fungal microbiota compared to external bare soil. Stem density and cushion height increase significantly with altitude, as does the nurse effect of the cushion on the growth and survival of co-existing vascular plants.Conclusions: As a result of cushion biogenic environmental changes, the effect of Astragalus on some of the co-existing species shifted from negative or null at 1650 m to facilitative along the elevation gradient. Furthermore, our data show a relationship between Astragalus morphological traits and soil biogenic changes related to soil chemistry and microbiota that affect plant interaction and coexistence.

AimsThe aims of this research were: i) to compare Cr, Cu, Ni and Pb concentrations in Quercus ilex L. leaves collected at urban/industrial and urban areas; ii) to investigate the main pathway of leaf metal accumulation; iii) to evaluate probable differences in traits of leaves at the investigated area typologies; iv) to relate leaf metal concentrations and to leaf traits.MethodsLeaves and soils were collected at six sites (three of urban area and three of urban/industrial area). Length, width, area, extract pH, relative water content, specific area and petiole length were evaluated in the leaves; besides, Cr, Cu, Ni and Pb concentrations were measured in unwashed and chloroform washed leaves, and in soils.ResultsThe comparison between leaves collected at the urban and urban/industrial area showed that higher Cr, Ni and Pb concentrations were measured at the urban/industrial area, greater leaves and longer petiole were observed at the urban area, whereas higher leaf extract pH were observed at the urban/industrial one. Air uptake seemed to be the main pathway of leaf metal accumulation, as soils were not metal contaminated.ConclusionsQ. ilex leaves highlighted a diffuse and conspicuous air metal pollution in both urban/industrial and urban areas, although differences between the site typologies were observed. In fact, leaves of the urban/industrial area showed higher inner concentrations of all the investigated metals, with the exception of Cu. A direct leaf uptake by the air can be supposed, as the soils were scarcely metal contaminated. Greater leaves and longer petiole, among the investigated leaf traits, appeared the main leaf responses to metal accumulation.

The identification of null or questionably expressed HLA allelic variants is a major issue in HLA diagnostics, because the mistyping of the aberrant expression of such alleles can have a major impact on the outcome of both hematopoietic stem cell transplantation (HSCT) and solid organ transplants. It is debated how questionable (Q) alleles, because of their unknown expression profile, should be considered in an allogenic HSCT setting. The HLA-B*38:55Q allele was detected as an HLA-B blank specificity; DNA sequencing identified a single polymorphism at position 373 in exon 3 (TGC > CGC), which results in the replacement of cysteine 101 with an arginine in the HLA-B heavy chain, thus, impairing disulfide bridge formation in the alpha-2 domain, essential for the normal expression of the HLA molecules. In order to determine the RNA and protein expression profile of this allelic variant, we analyzed antigenic expression at different levels, transcriptional and transductional, using a combination of cellular methods, such as serological testing and flow cytometric analysis, polymerase chain reaction (PCR) sequence-specific primer (SSP) cDNA group-specific amplification and immunocytochemical assay, demonstrating the prevalent cytoplasmatic distribution of the HLA-B*38:55Q protein. Our findings suggest that in matching process the HLA-B*38:55Q allele needs to be considered as a low expressed allele, able to elicit an allogenic T-cell response in vivo and impair the transplant outcome.

This paper elaborates on current and emerging issues involving the operation of the concept of permanent establishment (PE) in the national tax system and double tax treaty system of the Netherlands. The paper was written as a contribution (country report) to the seminar “New Trends in the Definition of Permanent Establishment”, organized by the Faculty of Economics and Law of the Università Cattolica Del Sacro Cuore under the aegis of the OECD and the Italian Council of Ministers. The seminar was held in Milan, Italy, on 26 November 2018.