130 research outputs found
Arsenic-induced DNA hypomethylation affects chromosomal instability in mammalian cells
Early genetic instability induced in dividing V79-Cl3 Chinese hamster cells by inorganic arsenic, as demonstrated in our previous investigation, was evidenced by aneuploidy and nuclear abnormalities, but not by chromosomal rearrangements. Here we report the results of cytogenetic and morphological analyses performed on the progeny of cells dividing at the end of sodium arsenite treatment after they had been expanded through 120 generations (ASO cells) and then cloned. The acquired genetic instability persisted and was increased by highly unstable chromosomal rearrangements, namely dicentric chromosomes and telomeric associations, which were not seen following acute exposure. A peculiar finding was the preferential involvement of a particular chromosome in dicentric rearrangements observed in some isolated ASO clones. Interestingly, by immunostaining with anti-5-methylcytosine antibodies the genome-wide DNA hypomethylation, induced by arsenic immediately after the acute treatment, was found to affect those ASO clones characterized by aneuploidy and chromosomal rearrangements. These findings demonstrate that short-term exposure to arsenic has long-term effects and suggest that genome-wide DNA hypomethylation enhances genetic instability
The endemic vascular flora of Peloritani Mountains (NE Sicily): Plant functional traits and phytogeographical relationships in the most isolated and fragmentary micro-plate of the Alpine orogeny
This study is aimed at (1) producing a complete and updated inventory of the endemic vascular flora of Peloritani Mountains, (2) defining the geographical limits of Peloritani, regarded here as a biogeographical district and (3) highlighting possible paleogeographic connections with other Mediterranean lands. The heterogeneity analysis of the endemic flora was performed by means of contingency tables, through the x 2 test. The endemic flora of this area consists of 129 specific and infraspecific taxa, of which 15 are restricted to the Peloritani Mountains. The analysis of habitats revealed that endemic taxa are most abundant on cliffs, rangelands, woods and garrigues. A large number of surveyed taxa are endemic to central-southern Italy and Sicily, while the number of endemic taxa in common with Calabria, Etna and Aeolian Islands turned out to be rather low, in spite of the geographical proximity. The endemic flora of Peloritani allows to emphasize palaeogeographical relationships not only with the neighbouring Mediterranean territories, but also with currently remote ones, such as southern Spain, Sardinia and Corsica. The phytogeographical framework substantiates the hypothesis that the Peloritani floristic district coincides with the limit given to Peloritani Mountains by structural geologists
The Querco-Fagetea class in Sicily: an example of boreal temperate vegetation in the central Mediterranean area
Cytogenetic manifestations associated with the reversion, by gene amplification, at the HGPRT locus in V79 Chinese hamster cells.
SummarySome HGPRT spontaneous revertants were isolated from a mutant line (E2) of V79 Chinese hamster cells and phenotypically characterized. Dot–Blot hybridization with a32P-Iabelled HGPRT probe revealed an increase in the number of HGPRT sequences in some of these revertants, suggesting the occurrence of gene amplification. Cytogenetic analysis performed in three of these revertants showed a characteristic abnormally banding region (ABR) on the elongated p arm of theXchromosome.In Situhybridization in one revertant (RHE2) showed that the amplified sequences reside on the p+arm of theXchromsome in two different localizations. Because of the very probable clonal origin of the revertant, these features indicate that the amplified sequences might rearrange after their integration into the chromosome
Persistent dysregulation of DNA methylation in cells with arsenic-induced genomic instability
The mechanisms by which arsenic-induced genomic instability is initiated and maintained are poorly understood. In previous studies long-term progression of chromosomal instability was typified by increasing aneuploidy in Chinese hamster V79 and human keratinocyte cells treated with arsenite for a 24 hr exposure period followed by growth in arsenic-free medium for 40-120 cell generations. In the current study the role of progressive DNA methylation changes was evaluated in long-term cell cultures after brief arsenite treatments as above. We have found altered genomic methylation patterns in cells that were briefly exposed to arsenic with evidence for widespread dysregulation of CpG methylation that persists for many population doublings after the treatment.
In V79 cell populations, progressive aneuploidy increases were notable by 50 cell generations after a 24 hr exposure to 1-10 uM arsenite. Dicentric chromosomes and/or telomeric associations, as well as complex chromosome rearrangements, occurred by 90 cells generations post treatment; and mutator and transformed phenotypes began to appear thereafter. This increasing genomic instability correlated with modifications of global DNA methylation patterns in V79 cells evaluated by 5-methylcytosine antibody binding and MeSAP-PCR. The results show that short-term exposure to arsenite induced an apparent genome hypomethylating effect within a short time after exposure.
In identical protocols using human HaCaT keratinocytes exposed to low doses of arsenite (0.05-0.1 M) for 24 hr, genomewide methylation levels were measured by LINE1 pyrosequencing and gene-specific methylation status was assessed by Methylation-Specific-PCR for up to 40 generations post exposure. Global demethylation following treatment was supported by preliminary LINE-1 studies. Moreover, the study of gene-specific MSP and determination of expression levels by RT-PCR of several genes (p16, hMLH1, hMSH2, DNMT1, DNMT3a and DNMT3b) demonstrated that hMSH2 gene was epigenetically regulated by arsenite and that down regulation of DNMT3a and DNMT3b genes occurred in an arsenite dose-dependent manner.
The results reported here demonstrate that acute 24 hr arsenic exposure promptly induces genome wide DNA hypomethylation, and support the hypothesis that the cells continue to undergo epigenetic reprogramming both at the gene and genomic levels in the absence of further arsenite treatment; thus likely contributing to long-lasting genomic instability that manifests as aberrant chromosomal, mutator and cell transformation effects
Floristic and vegetation changes on a small mediterranean island over the last century
A synthetic and updated overview about the vascular flora and vegetation of the Island of Capo Passero (SE‐Sicily) is provided. These data issue from two series of field surveys—the first carried out between 1997 and 2000, and the second between 2005 and 2019 and mostly focused on refining and implementing vegetation data. The current islet’s flora consists of 269 taxa, of which 149 (58%) are annual plants. The Mediterranean species are largely prevailing, 108 (40%) of which have a strictly Mediterranean biogeographical status. The comparison with a species list published in 1919 and updated in 1957 suggest that, despite the overall prevalence of anemochorous taxa, the vertebrate fauna represents an important vector for the plant colonization of the island, while the immigration of myrmechocorous taxa does not compensate the extinction rate. As many as 202 phy-tosociological relevés, 191 of which issue from original recent field surveys, enabled identifying 12 different plant communities. The comparison with a vegetation map published in 1965 suggests a strong reduction in dune habitats (2120 and 2210 according to EU ‘Habitats’ Directive 92/43), as well as a deep disruption in the succession typical of the local psammophilous vegetation series. In order to preserve rare, endangered and protected plant species (such as Aeluropus lagopoides, Cichorium spinosum, Limonium hyblaeum, L. syracusanum, Poterium spinosum, Senecio pygmaeus and Spergularia heldreichii) and to stop the ongoing habitat degradation, urgent and effective conservation measures should be adopted for this tiny, yet precious islet
The alien vascular flora of the Pantelleria Island National Park (Sicily Channel, Italy): new insights into the distribution of some potentially invasive species
Pantelleria is a volcanic island located in the Sicily Channel (Italy), between Sicily
and Tunisia. The island, designated a National Park in 2016, hosts an interesting
vascular flora of over 600 species including 9 narrow endemics. The island’s
incredible biodiversity is, however, at risk due to anthropogenic influences, climate
change, and, recently, the presence and spread of alien plant species. The
Pantelleria alien flora has never been thoroughly investigated, probably because
many non-native species were not yet present or so widespread on the island. Now,
however, with the increased general awareness of the risks associated with invasive
alien species, documentation of the presence of non-native species has been
steadily increasing. In this study, field and literature research was carried out to
investigate the alien flora of the island. Here, we report the status of a number of
non-native plants with known invasive potential. Cenchrus setaceus (=Pennisetum
setaceum) is reported for the first time as naturalized in the island with clear
invasive behaviour, while, particularly remarkable for their invasive potential are
other studied plants such as: Acacia saligna, Ailanthus altissima, Boheravia
coccinea, Carpobrotus edulis, Leucaena leucocephala subsp. glabrata, Malephora
crocea, Melia azedarach, Nicotiana glauca, Opuntia ficus-indica, Parkinsonia
aculeata, Washingtonia robusta and a few others less important at the moment, but
to be monitored. Although most taxa showed a relatively limited distribution, the
trend is to observe an increased invasiveness, which indicates that they can
potentially become invasive in Pantelleria as well in the next years or decades.
Their limited current distribution suggests that these species are in the early stages
of the general invasion curve, when intervention is feasible and most likely to
succeed. Therefore, it is most prudent to prioritize management for as many
potentially problematic nonnatives as possible, which will contribute greatly to the
conservation of native species and ecosystems of Pantelleria. Prevention and
management of invasive non-native species—both future arrivals and those already
present—are necessary to preserve the peculiar volcanic landscape of Pantelleria,
which was shaped by man over the last millennia
Are protected areas covering important biodiversity sites? An assessment of the nature protection network in Sicily (Italy)
GIS spatial analysis of three indicators (vegetation value, faunal richness and landscape heterogeneity) was used to detect and map High-Value Biodiversity Areas (HVBAs), estimate the coverage of biodiversity in the Sicilian protected areas network, and identify new priority areas that could improve long-term biodiversity conservation outcomes. Findings indicated that only 32% of HVBAs are currently covered by the protected areas network. Hotspot analysis revealed that a modest expansion (less than 1%) in the current extent of protected areas would include a disproportionate amount (56%) of biodiversity hotspots, and identified prioritized candidates HVBAs for designation of new protected areas. © 2018 Elsevier Lt
New national and regional Annex I Habitat records: From #37 to #44
In this contribution, Italian new data concerning the distribution of the Annex I Habitats 3150, 3170*, 3260, 4090, 91L0, 91M0, 9340 are reported. In detail, 20 new occurrences in Natura 2000 sites are presented and 30 new cells are added in the EEA 10 km × 10 km reference grid. The new data refer to the Italian administrative regions of Campania, Lazio, Sardinia, Sicily, Tuscany, and Umbria
Alnus glutinosa Riparian Woodlands of Italy and Corsica: Phytosociological Classification and Floristic Diversity
A comparative analysis of the riparian vegetation dominated by Alnus glutinosa in Italy and Tyrrhenian islands, based on literature data and unpublished releves, is presented. A total of 456 phytosociological releves were processed. For the definition of plant communities and alliances, hierarchical clustering was performed by using Bray-Curtis coefficient and Detrended Correspondence Analysis ordination methods. Identification of diagnostic species of the vegetation units was performed by means of the phi fidelity index. Quantum GIS software version 3.6 was used for the interpolation of the bioclimatic variables and A. glutinosa communities. Overall, a total of 18 A. glutinosa-riparian wood communities were distinguished for Italy and Tyrrhenian islands, of which two new associations and one new subassassociation are described. The classification of the releves showed two main vegetation groups: the first one including the plant communities of the Osmundo-Alnion alliance, and the other including the vegetation of the Ligustro vulgaris-Alnion glutinosae alliance. This latest includes the riparian meso-thermophilous communities of central and northern Italy. Within the Osmundo-Alnion alliance, two subgroups can be recognized: the first one includes the thermophilous communities of the Hyperico hircini-Alnenion glutinosae sub-alliance, mainly spread in the Tyrrhenian islands, while the second group includes the mesophilous communities attributed to the new suballiance Struthioptero-Alnenion glutinosae, widespread in central Italy and the Corsican mountains. The present paper provides the first comprehensive and exhaustive scheme of the A. glutinosa riparian woodlands diversity in Italy and Corsica
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