8 research outputs found

    The Endangered Sardinian Grass Snake: Distribution Update, Bioclimatic Niche Modelling, Dorsal Pattern Characterisation, and Literature Review

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    The Sardinian grass snake, Natrix helvetica cetti, is an endangered endemic snake subspecies with a restricted and highly fragmented geographic distribution. Information on its ecology and detailed geographic distribution are scarce and may negatively impact on its conservation status. Therefore, a literature review on its taxonomy, morphology, ecology, and conservation is presented here. Moreover, field records from the authors, citizen science and the existing literature provide an updated geographic distribution highlighting its presence within 13 new and 7 historic 10 x 10 km cells. Bioclimatic niche modelling was then applied to explore patterns of habitat suitability and phenotypic variation within N. h. cetti. The geographic distribution of the species was found to be positively correlated with altitude and precipitation values, whereas temperatures howed a negative correlation. Taken together, these outcomes may explain the snake’s presence, particularly in eastern Sardinia. In addition, analysis of distribution overlap with the competing viperine snake (N. maura) and the urodeles as possible overlooked trophic resources (Speleomantes spp. and Euproctus platycephalus) showed overlaps of 66% and 79%, respectively. Finally, geographical or bioclimatic correlations did not explain phenotypic variation patterns observed in this highly polymorphic taxon. Perspectives on future research to investigate N. h. cetti’s decline and support effective conservation measures are discussed

    Aliens Coming by Ships: Distribution and Origins of the Ocellated Skink Populations in Peninsular Italy

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    The ocellated skink (Chalcides ocellatus) is a widespread lizard, naturally distributed between the Maghreb and coastal Pakistan, with few insular populations in the Mediterranean coastal area. Some populations of this species have also been recorded in peninsular Italy, Campania and Southern Tuscany due to accidental introductions via touristic and commercial routes. In this work, we conducted genetic analyses on mitochondrial DNA COXI, cytb and 16S mtDNA genes on a sample of Italian insular and peninsular populations. Differently from what previously suggested, the nucleus in Portici (Southern Italy) may have originated from Sardinia. The intense trade and touristic traffic between Sardinia and Southern Tuscany may have been responsible for the introduction of this lizard also to Central Italy

    Dysfunction and functional restoration of HCV-specific CD8 responses in chronic hepatitis C virus infection

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    The functional impairment of HCV-specific T cell responses is believed to be an important determinant of HCV persistence, but the functional T cell defects of patients with chronic hepatitis C (CH-C) are only partially defined. CD8 responses to HLA-A2-restricted epitopes of HCV and other unrelated viruses were studied in 23 HLA-A2-positive patients both ex vivo and after in vitro culture. Degranulation capacity, intracellular perforin, and granzyme-A content and cytokine production (IFN-γ, TNF-α) by HCV- and non-HCV-specific CD8 cells were tested both ex vivo and in vitro, whereas cytolytic activity was studied after 10 days' expansion in vitro. Memory maturation and role of exhaustion were assessed ex vivo by HCV-specific CD8 staining for CD 127 and PD-1, and in vitro after peripheral blood mononuclear cells (PBMC) culture in the presence of anti-PD-L1 monoclonal antibodies. IFN-γ production and cytolytic activity were expressed less efficiently by HCV-specific than by non-HCV specific CD8 cells derived from the same CH-C patients. The amount of stored granzyme-A within single cells was always lower in HCV-specific CD8 cells, which were less efficient also in the release of lytic granules and in the production of TNF-α. The CD8 dysfunction was associated with high PD-1 expression by most HCV-specific CD8 cells, and PD-1/PD-L1 blockade by anti-PD-L1 antibodies in vitro was able to improve the HCV-specific CD8 function. Conclusion: Our study characterizes CD8 defects that may be important in maintaining HCV persistence; identification of strategies to correct these defects may help to define novel approaches to treat HCV infection. Copyright © 2007 by the American Association for the Study of Liver Diseases

    Il «Parnaso de’ moderni artisti»: le collezioni artistiche di Ambrogio Uboldo

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