107 research outputs found
Phytosociological and ecological study of springs in Trentino (south-eastern Alps, Italy)
A phytosociological survey of the crenic vegetation was made in Trentino (south-eastern Alps), combining the field method of the Braun-Blanquet approach with a numerical syntaxonomical analysis. A set of 139 phytosociological releves, including vascular plants and bryophytes, were classified using cluster analysis. The vegetation types were assigned to 7 different phytosociological classes: Platyhypnidio-Fontinalietea antipyreticae, Montio-Cardaminetea, Adiantetea, Scheuchzerio-Caricetea nigrae, Molinio- Arrhenatheretea, Galio-Urticetea, Mulgedio-Aconitetea. The classes Platyhypnidio-Fontinalietea antipyreticae and Montio- Cardaminetea represent the core of crenic vegetation, including permanently or intermittently submerged plant communities, mostly made up of bryophytes, or non-submerged communities dominated by bryophytes or vascular plants. The other classes include chasmophytic bryophyte-rich communities and hygrophilous or tall herb communities lying around the periphery of the springs. 23 vegetation types were identified and, whenever possible, classified at the association level, or as phytocoena. The environmental parameters showed different ranges among vegetation types. A number of environmental variables were recorded during the vegetation survey, including altitude, shading, discharge, flow velocity, with exhaustive hydrochemical sampling. Conductivity, alkalinity and pH showed similar distribution patterns, clearly separating the vegetation types into two distinct groups, differing in the nature of the substratum. The altitudinal range was very broad and shading was also very variable. Nitrate and phosphate levels showed that the majority of vegetation types were irrigated by oligotrophic crenic waters. Finally, the bryophyte-dominated vegetation types belonging to the class Platyhypnidio-Fontinalietea antipyreticae occurred in springs with the highest discharge values and variation. Discriminant analysis confirmed that the environmental descriptors that best accounted for the among-group variation were pH and alkalinity (first variate); the second variate reflected a gradient of altitude and discharge
Ecological profiles of wetland plant species in the northern Apennines (N. Italy)
Eighteen selected species occurring in the wetlands of the northern Apennines were studied by the ecological profile method. By this method, it is possible to identify the ecological factors mostly influencing species distribution within a particular vegetation. Moreover, it is possible to evaluate both ecological amplitude and ecological preferences of species. Ecological profiles were built for three factors (altitude, pH and electrical conductivity) from a data set of 265 phytosociological relevés, used for altitude, and from a set of 92 measures, carried out in selected sites, for idrochemical variables. By numerical classification, based on chord distance and minimum variance, the ecological species groups for each factor were individuated. Subsequently, they were ordered by correspondence analysis for detecting relationships between ecological groups and classes of factors. By applying a goodness-of-fit test to ecological profiles, the species significantly deviating from uniformity were detected. They can be regarded as indicators for the corresponding ecological factor. We found seven indicator species for altitude (Carex nigra, C. rostrata, Juncus filiformis, J. alpino-articulatus, Eriophorum latifolium, E. angustifolium and Warnstorfia exannulata), four indicator species for electrical conductivity (Campylium stellatum, Carex tumidicarpa, Eriophorum latifolium and Juncus alpino-articulatus) and one indicator species for pH (Sphagnum capillifolium). The ecological profiles of the wetland species in the northern Apennines were compared with those reported in literature for the same species from the Alps (namely Dolomites). In this way, a certain degree of ecological shift in several wetland species of the northern Apennines was documented. For altitude, it is possible to explain the shift considering the reduced elevational amplitude of northern Apennine wetlands with respect to those of the Alps. For pH, Sphagnum capillifolium occurs in less acidic habitats than in the Alps, probably due to the absence of ombrotrophic mires, and Viola palustris occurs mostly in neutro- basiphytic habitats. Some hypotheses to explain the ecological behaviour of this last species were proposed
Range expansion of muskox lungworms track rapid arctic warming: implications for geographic colonization under climate forcing
Rapid climate warming in the Arctic results in multifaceted disruption of biodiversity, faunal structure, and ecosystem health. Hypotheses have linked range expansion and emergence of parasites and diseases to accelerating warming globally but empirical studies demonstrating causality are rare. Using historical data and recent surveys as baselines, we explored climatological drivers for Arctic warming as determinants of range expansion for two temperature-dependent lungworms, Umingmakstrongylus pallikuukensis and Varestrongylus eleguneniensis, of muskoxen (Ovibos moschatus) and caribou (Rangifer tarandus), in the Canadian Arctic Archipelago from 1980 through 2017. Our field data shows a substantial northward shift of the northern edge of the range for both parasites and increased abundance across the expanded ranges during the last decade. Mechanistic models parameterized with parasitesâ thermal requirements demonstrated that geographical colonization tracked spatial expansion of permissive environments, with a temporal lag. Subtle differences in life histories, thermal requirements of closely related parasites, climate oscillations and shifting thermal balances across environments influence faunal assembly and biodiversity. Our findings support that persistence of host-parasite assemblages reflects capacities of parasites to utilize host and environmental resources in an ecological arena of fluctuating opportunity (alternating trends in exploration and exploitation) driving shifting boundaries for distribution across spatial and temporal scales
Analysis and evaluation of abandoned railways aimed at greenway conversion: A methodological application in the Sicilian landscape using multi-criteria analysis and geographical information system
Nowadays, in many countries around the world, abandoned railways are considered as important resources that can be recovered and converted into greenways, thanks to their specific adaptability to this function. With its about 1000 km of dismantled lines, Sicily is the Italian region where the abandonment of railways is more evident. Nevertheless, to the present day, only about 20 km have been converted in greenways. As a recovery action requires large investments, it is necessary to determine a priority list based on the actual suitability of a track to be converted. Therefore, the aim of this paper was to define and apply a methodology, based on multi-criteria analysis associated with geographical information system (GIS), for the assessment of different suitability degrees of an abandoned railway to be converted in greenway for agro-touristic and cultural use of the land. The work was developed on two abandoned railway lines, sited in the province of Syracuse, embedded in landscapes of great value thanks to the existence of natural areas and cultural heritage. The applied method attributes great importance to the quality of the landscape that is considered in the same way as the intrinsic characteristics of the track. Several indicators were weighed and spatially mapped to describe the local resources at the margin of the track and the characteristics of the stretches of the two lines. The GIS analysis allowed obtaining various intermediate maps containing the necessary information for drawing the ultimate maps, which showed the suitability of each line to be converted in greenway. The results showed that the suitability level depends on the specific characteristics of the railroad and its marginal values, as well as on the quality of the landscape and the development opportunities that it offers. The creation of greenways can thus become a support to make easier the integration between the landscape and the growing demands of land, economic and tourist development, while maintaining intact the rural land and favoring its connection with the urban centers. The study, although referred to specific territorial areas, is generally valid from a methodological point of view and can be applied in other contexts
Isolation and characterization of CD146+ multipotent mesenchymal stromal cells
Mesenchymal stromal cells (MSCs) represent a bone marrow (BM) population, classically defined by five functional properties: extensive proliferation, ability to differentiate into osteoblasts, chondrocytes, adipocytes, and stromal cellsâsupporting hematopoiesis. However, research progress in this area has been hampered by lack of suitable markers and standardized procedures for MSC isolation. We have isolated a CD146+ multipotent MSC population from 20 human BM donors displaying the phenotype of self-renewing osteoprogenitors; an extensive 12-week proliferation; and the ability to differentiate in osteoblasts, chondrocytes, adipocytes, and stromal cells supporting hematopoiesis. Furthermore, the CD146+ MSCs secrete a complex combination of growth factors (GFs) controlling hematopoietic stem cells (HSCs) function, while providing a >2-log increase in the long-term culture (LTC) colony output in 8-week LTC over conventional assays. The hematopoietic stromal function exhibited by the MSCs was further characterized by manipulating LTCs with the chemical inhibitors Imatinib or SU-5416, targeting two GF receptors (GFRs), KIT or VEGFR2/1, respectively. Both treatments similarly impaired LTC colony output, indicating key roles for these two GF/GFR interactions to support LTC-initiating cell activity. CD146+ MSCs may thus represent a tool to explore the MSC-HSC cross-talk in an in vitro surrogate model for HSC âniches,â and for regenerative therapy studies. In addition, the MSC microRNA (miRNA) expression profile was analyzed by microarrays in both basic conditions and chondrogenic differentiation. Our analysis revealed that several miRNAs are modulated during chondrogenesis, and many of their putative targets are genes involved in chondrogenic differentiation
Intraspecific Functional Trait Response to Advanced Snowmelt Suggests Increase of Growth Potential but Decrease of Seed Production in Snowbed Plant Species
In ecological theory, it is currently unclear if intraspecific trait responses to environmental variation are shared across plant species. We use one of the strongest environmental variations in alpine ecosystems, i.e., advanced snowmelt due to climate warming, to answer this question for alpine snowbed plants. Snowbeds are extreme habitats where long-lasting snow cover represents the key environmental factor affecting plant life. Intraspecific variation in plant functional traits is a key to understanding the performance and vulnerability of species in a rapidly changing environment. We sampled snowbed species after an above-average warm winter to assess their phenotypic adjustment to advanced snowmelt, based on differences in the natural snowmelt dynamics with magnitudes reflecting predicted future warming. We measured nine functional traits related to plant growth and reproduction in seven vascular species, comparing snowbeds of early and late snowmelt across four snowbed sites in the southern Alps in Italy. The early snowbeds provide a proxy for the advanced snowmelt caused by climatic warming. Seed production was reduced under advanced snowmelt in all seed-forming snowbed species. Higher specific leaf area (SLA) and lower leaf dry matter content (LDMC) were indicative of improved growth potential in most seed-forming species under advanced snowmelt. We conclude, first, that in the short term, advanced snowmelt can improve snowbed speciesâ growth potential. However, in the long term, results from other studies hint at increasing competition in case of ongoing improvement of conditions for plant growth under continued future climate warming, representing a risk for snowbed species. Second, a lower seed production can negatively affect the seed rain. A reduction of propagule pressure can be crucial in a context of loss of the present snowbed sites and the formation of new ones at higher altitudes along with climate warming. Finally, our findings encourage using plant functional traits at the intraspecific level across species as a tool to understand the future ecological challenges of plants in changing environments
ADAR1 is a new target of METTL3 and plays a pro-oncogenic role in glioblastoma by an editing-independent mechanism
Background: N6-methyladenosine (m6A) and adenosine-to-inosine (A-to-I) RNA editing are two of the most abundant RNA modification events affecting adenosines in mammals. Both these RNA modifications determine mRNA fate and play a pivotal role in tumor development and progression.
Results: Here, we show that METTL3, upregulated in glioblastoma, methylates ADAR1 mRNA and increases its protein level leading to a pro-tumorigenic mechanism connecting METTL3, YTHDF1, and ADAR1. We show that ADAR1 plays a cancer-promoting role independently of its deaminase activity by binding CDK2 mRNA, underlining the importance of ADARs as essential RNA-binding proteins for cell homeostasis as well as cancer progression. Additionally, we show that ADAR1 knockdown is sufficient to strongly inhibit glioblastoma growth in vivo.
Conclusions: Hence, our findings underscore METTL3/ADAR1 axis as a novel crucial pathway in cancer progression that connects m6A and A-to-I editing post-transcriptional events
Lâimmigrazione nella trasformazione dei contesti urbani: il caso siciliano, lâesigenza del recupero culturale ed il rifiuto della marginalizzazione
The issue of the immigration leads to reorganize the whole social architecture of the societies in which it occurs. Considering the urban environment as a microcosm which has a great deal of influence on global dynamics, it is right to think about the living conditions of urban citizens who live in the multicultural present societies, often suffering marginalization. As the last researches claim, the local government system is the one that could help to deal with the immigration matter in the best way and this also needs to be urgently addressed, as the âImmigration in Sicilyâ case study could show
ï»żTaxonomic and ecological remarks on Solenopsis bivonae species complex (Campanulaceae)
The populations usually attributed to Solenopsis bivonae (Tineo) M.B.Crespo, Serra & A.Juan are investigated from a taxonomical and morphological viewpoint. Within this species complex, four new subspecies occurring in Sicily and Calabria are recognized, such as subsp. bivonae, subsp. madoniarum, subsp. peloritana and subsp. brutia. In addition, a new species from Cyprus described as S. meikleana and S. bacchettae from Sardinia must be included in this group. The synonymy, typification, description, seed testa morphology, chorology, ecology, illustrations, conservation status, and examined specimens for each taxon are provided. Besides, the analytical keys, distribution maps, and phytosociological arrangement regarding these taxa are given too
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