225 research outputs found

    Ptch2/Gas1 and Ptch1/Boc differentially regulate Hedgehog signalling in murine primordial germ cell migration.

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    Gas1 and Boc/Cdon act as co-receptors in the vertebrate Hedgehog signalling pathway, but the nature of their interaction with the primary Ptch1/2 receptors remains unclear. Here we demonstrate, using primordial germ cell migration in mouse as a developmental model, that specific hetero-complexes of Ptch2/Gas1 and Ptch1/Boc mediate the process of Smo de-repression with different kinetics, through distinct modes of Hedgehog ligand reception. Moreover, Ptch2-mediated Hedgehog signalling induces the phosphorylation of Creb and Src proteins in parallel to Gli induction, identifying a previously unknown Ptch2-specific signal pathway. We propose that although Ptch1 and Ptch2 functionally overlap in the sequestration of Smo, the spatiotemporal expression of Boc and Gas1 may determine the outcome of Hedgehog signalling through compartmentalisation and modulation of Smo-downstream signalling. Our study identifies the existence of a divergent Hedgehog signal pathway mediated by Ptch2 and provides a mechanism for differential interpretation of Hedgehog signalling in the germ cell niche

    Ecology and technological capability of lactic acid bacteria isolated during Grillo grape vinification in the Marsala production area.

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    Grapes of “Grillo” variety, used to produce Marsala wine, were harvested from five vineyards different for climatic and agronomic parameters, in order to obtain a first mapping of lactic acid bacteria (LAB) inhabiting the production area. Marsala base wine production was followed at large-scale and two experimental vinifications, different for lysozyme and SO2 concentration and combination, were carried out at pilot-plant scale. LAB communities and conventional chemical parameters were periodically analysed. LAB were found on grapes at an average concentration of about 102 CFU g-1 which decreased during the transformation process. A total of 146 colonies were collected, but only 35 were recognized as presumptive LAB. On the basis of phenotypic differences and isolation source, 16 isolates were then subjected to genotypic identification and gathered into the following species: Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Enterococcus faecium, Leuconostoc fallax and Sporalactobacillus nakayamae subsp. nakayamae. Lactococcus lactis subsp. lactis strains was the species most frequently isolated during winemaking showing the highest resistance to SO2 and lysozyme

    International Veterinary Epilepsy Task Force recommendations for a veterinary epilepsy-specific MRI protocol

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    Epilepsy is one of the most common chronic neurological diseases in veterinary practice. Magnetic resonance imaging (MRI) is regarded as an important diagnostic test to reach the diagnosis of idiopathic epilepsy. However, given that the diagnosis requires the exclusion of other differentials for seizures, the parameters for MRI examination should allow the detection of subtle lesions which may not be obvious with existing techniques. In addition, there are several differentials for idiopathic epilepsy in humans, for example some focal cortical dysplasias, which may only apparent with special sequences, imaging planes and/or particular techniques used in performing the MRI scan. As a result, there is a need to standardize MRI examination in veterinary patients with techniques that reliably diagnose subtle lesions, identify post-seizure changes, and which will allow for future identification of underlying causes of seizures not yet apparent in the veterinary literature. There is a need for a standardized veterinary epilepsy-specific MRI protocol which will facilitate more detailed examination of areas susceptible to generating and perpetuating seizures, is cost efficient, simple to perform and can be adapted for both low and high field scanners. Standardisation of imaging will improve clinical communication and uniformity of case definition between research studies. A 6–7 sequence epilepsy-specific MRI protocol for veterinary patients is proposed and further advanced MR and functional imaging is reviewed

    Association between Grape Yeast Communities and the Vineyard Ecosystems

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    The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Acores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viti-cultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions.Joao Drumonde Neves is the recipient of a fellowship of the Azorean Government (M321/006/F/2008) and PROEMPREGO. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds through FCT by the projects FCOMP-01-0124-008775, PTDC/AGR-ALI/103392/2008 and PTDC/AGR-ALI/121062/2010.info:eu-repo/semantics/publishedVersio

    Mantle Pb paradoxes : the sulfide solution

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    Author Posting. © Springer, 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Contributions to Mineralogy and Petrology 152 (2006): 295-308, doi:10.1007/s00410-006-0108-1.There is growing evidence that the budget of Pb in mantle peridotites is largely contained in sulfide, and that Pb partitions strongly into sulfide relative to silicate melt. In addition, there is evidence to suggest that diffusion rates of Pb in sulfide (solid or melt) are very fast. Given the possibility that sulfide melt ‘wets’ sub-solidus mantle silicates, and has very low viscosity, the implications for Pb behavior during mantle melting are profound. There is only sparse experimental data relating to Pb partitioning between sulfide and silicate, and no data on Pb diffusion rates in sulfides. A full understanding of Pb behavior in sulfide may hold the key to several long-standing and important Pb paradoxes and enigmas. The classical Pb isotope paradox arises from the fact that all known mantle reservoirs lie to the right of the Geochron, with no consensus as to the identity of the “balancing” reservoir. We propose that long-term segregation of sulfide (containing Pb) to the core may resolve this paradox. Another Pb paradox arises from the fact that the Ce/Pb ratio of both OIB and MORB is greater than bulk earth, and constant at a value of 25. The constancy of this “canonical ratio” implies similar partition coefficients for Ce and Pb during magmatic processes (Hofmann et al. 1986), whereas most experimental studies show that Pb is more incompatible in silicates than Ce. Retention of Pb in residual mantle sulfide during melting has the potential to bring the bulk partitioning of Ce into equality with Pb if the sulfide melt/silicate melt partition coefficient for Pb has a value of ~ 14. Modeling shows that the Ce/Pb (or Nd/Pb) of such melts will still accurately reflect that of the source, thus enforcing the paradox that OIB and MORB mantles have markedly higher Ce/Pb (and Nd/Pb) than the bulk silicate earth. This implies large deficiencies of Pb in the mantle sources for these basalts. Sulfide may play other important roles during magmagenesis: 1). advective/diffusive sulfide networks may form potent metasomatic agents (in both introducing and obliterating Pb isotopic heterogeneities in the mantle); 2). silicate melt networks may easily exchange Pb with ambient mantle sulfides (by diffusion or assimilation), thus ‘sampling’ Pb in isotopically heterogeneous mantle domains differently from the silicate-controlled isotope tracer systems (Sr, Nd, Hf), with an apparent ‘de-coupling’ of these systems.Our intemperance should not be blamed on the support we gratefully acknowledge from NSF: EAR- 0125917 to SRH and OCE-0118198 to GAG

    Platinum-group elements, S, Se and Cu in highly depleted abyssal peridotites from the Mid-Atlantic Ocean Ridge (ODP Hole 1274A): Influence of hydrothermal and magmatic processes

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    Highly depleted harzburgites and dunites were recovered from ODP Hole 1274A, near the intersection between the Mid-Atlantic Ocean Ridge and the 15°20â€ČN Fracture Zone. In addition to high degrees of partial melting, these peridotites underwent multiple episodes of melt-rock reaction and intense serpentinization and seawater alteration close to the seafloor. Low concentrations of Se, Cu and platinum-group elements (PGE) in harzburgites drilled at around 35-85 m below seafloor are consistent with the consumption of mantle sulfides after high degrees (>15-20 %) of partial melting and redistribution of chalcophile and siderophile elements into PGE-rich residual microphases. Higher concentrations of Cu, Se, Ru, Rh and Pd in harzburgites from the uppermost and lowest cores testify to late reaction with a sulfide melt. Dunites were formed by percolation of silica- and sulfur-undersaturated melts into low-Se harzburgites. Platinum-group and chalcophile elements were not mobilized during dunite formation and mostly preserve the signature of precursor harzburgites, except for higher Ru and lower Pt contents caused by precipitation and removal of platinum-group minerals. During serpentinization at low temperature (<250 °C) and reducing conditions, mantle sulfides experienced desulfurization to S-poor sulfides (mainly heazlewoodite) and awaruite. Contrary to Se and Cu, sulfur does not record the magmatic evolution of peridotites but was mostly added in hydrothermal sulfides and sulfate from seawater. Platinum-group elements were unaffected by post-magmatic low-temperature processes, except Pt and Pd that may have been slightly remobilized during oxidative seawater alteration

    Yeast biodiversity in vineyard environments is increased by human intervention

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    One hundred and five grape samples were collected during two consecutive years from 33 locations on seven oceanic islands of the Azores Archipelago. Grape samples were obtained from vineyards that were either abandoned or under regular cultivation involving common viticultural interventions, to evaluate the impact of regular human intervention on grape yeast biota diversity in vineyards. A total of 3150 yeast isolates were obtained and 23 yeast species were identified. The predominant species were Hanseniaspora uvarum, Pichia terricola, Starmerella bacillaris and Issatchenkia hanoiensis. The species Barnettozyma californica, Candida azymoides and Pichia cecembensis were reported in grapes or wine-associated environments for the first time. A higher biodiversity was found in active vineyards where regular human intervention takes place (Shannon index: 1.89 and 1.53 in the first and second years, respectively) when compared to the abandoned ones (Shannon index: 0.76 and 0.31). This finding goes against the assumptions that human intervention can destroy biodiversity and lead to homogeneity in the environment. Biodiversity indices were considerably lower in the year with the heaviest rainfall. This study is the first to report on the grape yeast communities from several abandoned vineyards that have undergone no human intervention.Joao Drumonde Neves is the recipient of a fellowship of the Azorean Government (M321/006/F/2008) and PROEMPREGO. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds through FCT by the projects FCOMP-01-0124-008775, PTDC/AGR-ALI/103392/2008 and PTDC/AGR-ALI/121062/2010.info:eu-repo/semantics/publishedVersio

    Seriously personal:The reasons that motivate entrepreneurs to address climate change

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    This is the author accepted manuscript. The final version is freely available from Springer Verlag via the DOI in this record.Scholars increasingly argue that entrepreneurs and their small- and medium-sized enterprises should play a central role in reducing the rate and magnitude of climate change. However, evidence suggests that while some entrepreneurs recognize their crucial role in addressing climate change, most do not. Why some entrepreneurs nevertheless concern themselves with climate change has largely been overlooked. Some initial work in this area tentatively suggests that these entrepreneurs may engage with climate change because of their personal values, which either focus on financial or socio-ecological reasons, or a combination of both. Yet, it is unclear if all for-profit entrepreneurs engage with climate change for the same reasons, or if indeed their motivations vary across business types. Over a period of four years, we examined entrepreneurs’ motivations to engage with climate change through a variety of qualitative research methods. Our findings illustrate how entrepreneurs who address climate change have motivations specific to their business activity/industry and level of maturity. In each instance, we link these motivations to distinct conceptualizations of time and place. We contend that, through a more differentiated understanding of entrepreneurial motivations, policy-makers can draft climate change-related policies tailored to entrepreneurial needs. Policies could both increase the number of entrepreneurs who already engage in climate change mitigation and leverage the impact of those entrepreneurs already mitigating climate change.This study was funded by the European Social Fund (09099NCO5). We acknowledge with thanks the participation of the entrepreneurs and the support of Business Leaders for Low Carbon, Cornwall Council, and Cornwall Sustainable Tourism Project. The authors wish to thank Professor John Amis, Professor Kenneth Amaeshi and the anonymous reviewers who provided useful feedback on earlier versions of the article
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