313 research outputs found

    The role of the carbohydrates in plasmatic membrane.

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    In the following paper, authors describe glycans present on cell membranes as they affect the folding, the spatial arrangement, the behavior and the interaction with the substrate of some membrane proteins. Authors describe the synthesis and assembly of a glycan on a protein, the formation of N-glycans, the maturation of an N-glycan in different cellular compartments, the structure of the glycocalyx and how it interacts with any pathogens. The study of the E-cadherin and the potassium channel to demonstrate how glycans affect the spatial arrangement, the stability and activity of the glycoproteins on the membranes. Subsequently, authors analyze the correlation between disorder glycosylation and human health. Authors define glycosylation disorders as a genetic defect that alter the structure or biosynthesis of glycans (sugar chains) in one or more biosynthetic pathways. Human glycosylation disorders reflect the disruption of early steps in the pathways of glycan biosynthesis. More in details, authors analyze the role of glycoprotein in tumor cell adhesion, in particular, in cells MCF-7 and MDA-MB-231 on zeolite scaffold. In the same time, the role of metalloproteinase is described in the mobilization of cancer cells and in metastasis

    THE CAPO ROSSELLO BORE-HOLE (AGRIGENTO, SICILY) CYCLOSTRATIGRAPHIC AND PALEOCEANOGRAPHIC RECONSTRUCTIONS FROM QUANTITATIVE ANALYSES OF THE ZANCLEAN FORAMINIFERAL ASSEMBLAGES

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    Cyclostratigraphy based on the quantitative analyses of planktonic foraminifera in the Zanclean segment (M Pl 1 base of M Pl 3 biozones) of the bore-hole drilled in the Capo Rossello area (Sicily, Southern Italy) allows us to recognize that the calcareous plankton biostratigraphic events occur in the same cycles as identified by previous authors. Exceptional thick cycles which are thought to represent two precession cycles show two fluctuations is greater than the number of lithologic cycles. Between the base of the Pliocene and the first occurrence of Globorotalia puncticulata thirty-five lithologic cycles and thirty eight planktonic foraminifera fluctuations are present. By comparison with relative abundance fluctuations in the benthic foraminifera and the astronomical record is recognized. In particular, the BN>125 µm and the Planulina ariminensis quantitative distributions are related to the long eccentricity. Conversely, the relative abundance fluctuations of Siphonina reticulata, Cibicidoides bradyi, Pullenia bulloides and Uvigerina pygmaea appear to be generally forced by the precession periodicity, but in the intervals coincident with the eccentricity minima such a relationship is less clear. The very abundant and widespread distribution in several Mediterranean sites of S. reticulata, which we consider a quasi-endemic species of this basin during the Early and Middle Pliocene is anticovariant with the quantitative distribution of Cibicidoides brady-robertsonianus, which is considered a characteristic species of the North Atlantic Deep Water (NADW). This relationship suggest that a peculiar, intermediate water mass was present in the Mediterranean during this time interval. We propose for this water mass the name of Early Pliocene Mediterranenan Intermediate Water (EPMIW). According to bibliographic data that report the sharp decrease in abundance of S. reticulata during the M Pl 5 biozone, EPMIW was present in the Mediterranean basin until about 2.5 Ma.&nbsp

    THE CAPO ROSSELLO BORE-HOLE (AGRIGENTO, SICILY) CYCLOSTRATIGRAPHIC AND PALEOCEANOGRAPHIC RECONSTRUCTIONS FROM QUANTITATIVE ANALYSES OF THE ZANCLEAN FORAMINIFERAL ASSEMBLAGES

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    Cyclostratigraphy based on the quantitative analyses of planktonic foraminifera in the Zanclean segment (M Pl 1 base of M Pl 3 biozones) of the bore-hole drilled in the Capo Rossello area (Sicily, Southern Italy) allows us to recognize that the calcareous plankton biostratigraphic events occur in the same cycles as identified by previous authors. Exceptional thick cycles which are thought to represent two precession cycles show two fluctuations is greater than the number of lithologic cycles. Between the base of the Pliocene and the first occurrence of Globorotalia puncticulata thirty-five lithologic cycles and thirty eight planktonic foraminifera fluctuations are present. By comparison with relative abundance fluctuations in the benthic foraminifera and the astronomical record is recognized. In particular, the BN>125 µm and the Planulina ariminensis quantitative distributions are related to the long eccentricity. Conversely, the relative abundance fluctuations of Siphonina reticulata, Cibicidoides bradyi, Pullenia bulloides and Uvigerina pygmaea appear to be generally forced by the precession periodicity, but in the intervals coincident with the eccentricity minima such a relationship is less clear. The very abundant and widespread distribution in several Mediterranean sites of S. reticulata, which we consider a quasi-endemic species of this basin during the Early and Middle Pliocene is anticovariant with the quantitative distribution of Cibicidoides brady-robertsonianus, which is considered a characteristic species of the North Atlantic Deep Water (NADW). This relationship suggest that a peculiar, intermediate water mass was present in the Mediterranean during this time interval. We propose for this water mass the name of Early Pliocene Mediterranenan Intermediate Water (EPMIW). According to bibliographic data that report the sharp decrease in abundance of S. reticulata during the M Pl 5 biozone, EPMIW was present in the Mediterranean basin until about 2.5 Ma.&nbsp

    Mediterranean circulation perturbations over the last five centuries: Relevance to past Eastern Mediterranean Transient-type events

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    The Eastern Mediterranean Transient (EMT) occurred in the Aegean Sea from 1988 to 1995 and is the most significant intermediate-to-deep Mediterranean overturning perturbation reported by instrumental records. The EMT was likely caused by accumulation of high salinity waters in the Levantine and enhanced heat loss in the Aegean Sea, coupled with surface water freshening in the Sicily Channel. It is still unknown whether similar transients occurred in the past and, if so, what their forcing processes were. In this study, sediments from the Sicily Channel document surface water freshening (SCFR) at 1910 ± 12, 1812 ± 18, 1725 ± 25 and 1580 ± 30 CE. A regional ocean hindcast links SCFR to enhanced deep-water production and in turn to strengthened Mediterranean thermohaline circulation. Independent evidence collected in the Aegean Sea supports this reconstruction, showing that enhanced bottom water ventilation in the Eastern Mediterranean was associated with each SCFR event. Comparison between the records and multi-decadal atmospheric circulation patterns and climatic external forcings indicates that Mediterranean circulation destabilisation occurs during positive North Atlantic Oscillation (NAO) and negative Atlantic Multidecadal Oscillation (AMO) phases, reduced solar activity and strong tropical volcanic eruptions. They may have recurrently produced favourable deep-water formation conditions, both increasing salinity and reducing temperature on multi-decadal time scales

    COVID-19 lockdowns reveal the resilience of Adriatic Sea fisheries to forced fishing effort reduction

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    The COVID-19 pandemic provides a major opportunity to study fishing effort dynamics and to assess the response of the industry to standard and remedial actions. Knowing a fishing fleet’s capacity to compensate for effort reduction (i.e., its resilience) allows differentiating governmental regulations by fleet, i.e., imposing stronger restrictions on the more resilient and weaker restrictions on the less resilient. In the present research, the response of the main fishing fleets of the Adriatic Sea to fishing hour reduction from 2015 to 2020 was measured. Fleet activity per gear type was inferred from monthly Automatic Identification System data. Pattern recognition techniques were applied to study the fishing effort trends and barycentres by gear. The beneficial effects of the lockdowns on Adriatic endangered, threatened and protected (ETP) species were also estimated. Finally, fleet effort series were examined through a stock assessment model to demonstrate that every Adriatic fishing fleet generally behaves like a stock subject to significant stress, which was particularly highlighted by the pandemic. Our findings lend support to the notion that the Adriatic fleets can be compared to predators with medium-high resilience and a generally strong impact on ETP species

    DTM-based morphometry of the Palinuro seamount (Eastern Tyrrhenian Sea): Geomorphological and volcanological implications

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    We present a high resolution DTM of the Palinuro Seamount (PS, Tyrrhenian Sea, Italy) resulting from the processing of multibeam swath bathymetry records acquired during the second leg of the “Aeolian 2007” cruise. PS consists of several superimposed volcanoes aligned along a N100°E strike and measures 55×25 km. The western and the central sectors result from the coalescence of collapse structures (calderas) with younger volcanic cones. The eastern sector reveals a more complex and articulated structure. In the central sector, a volcanic crater with a well-preserved rim not obliterated by erosional events suggests a volcanological rejuvenation of this sector. The presence of flat surfaces on the top of the seamount may be due to the formation of marine terraces during the last sea-level lowering. Lateral collapses on the northern and southern flanks of the seamount are probably related to slope instability, as suggested by the presence of steep slopes (25–40°). The main fault affecting PS strikes N65°E and shows a right lateral component of movement. E–W and N10°E striking faults are also present. Assuming that theN100°E deep-seated fault,which is responsible for theemplacement of PS,movedwith sinistral slips, we interpret the N65°E and the N10°E faults as right-lateral (second order) shear and left-lateral (third order) shear, respectively. Due to the particular location of the Palinuro Seamount, the data presented here allow us to better understand the volcanism and the geodynamic processes of the Tyrrhenian Sea

    The impact of the Little ice age on coccolithophores in the central Mediterranea Sea

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    The Little ice age (LIA) is the last episode of a series of Holocene climatic anomalies. There is still little knowledge on the response of the marine environment to the pronounced cooling of the LIA and to the transition towards the 20th century global warming. Here we present decadal-scale coccolithophore data from four short cores recovered from the central Mediterranean Sea (northern Sicily Channel and Tyrrhenian Sea), which on the basis of ²¹⁰Pb activity span the last 200-350 years. The lowermost part of the record of one of the cores from the Sicily Channel, Station 407, which extends down to 1650 AD, is characterized by drastic changes in productivity. Specifically, below 1850 AD, the decrease in abundance of F. profunda and the increase of placoliths, suggest increased productivity. The chronology of this change is related to the main phase of the Little Ice Age, which might have impacted the hydrography of the southern coast of Sicily and promoted vertical mixing in the water column. The comparison with climatic forcings points out the importance of stronger and prolonged northerly winds, together with decreased solar irradiance

    DTM-based morphometry of the Palinuro seamount (Eastern Tyrrhenian Sea): Geomorphological and volcanological implications

    Get PDF
    We present a high resolution DTM of the Palinuro Seamount (PS, Tyrrhenian Sea, Italy) resulting from the processing of multibeam swath bathymetry records acquired during the second leg of the “Aeolian 2007” cruise. PS consists of several superimposed volcanoes aligned along a N100°E strike and measures 55×25 km. The western and the central sectors result from the coalescence of collapse structures (calderas) with younger volcanic cones. The eastern sector reveals a more complex and articulated structure. In the central sector, a volcanic crater with a well-preserved rim not obliterated by erosional events suggests a volcanological rejuvenation of this sector. The presence of flat surfaces on the top of the seamount may be due to the formation of marine terraces during the last sea-level lowering. Lateral collapses on the northern and southern flanks of the seamount are probably related to slope instability, as suggested by the presence of steep slopes (25–40°). The main fault affecting PS strikes N65°E and shows a right lateral component of movement. E–W and N10°E striking faults are also present. Assuming that theN100°E deep-seated fault,which is responsible for theemplacement of PS,movedwith sinistral slips, we interpret the N65°E and the N10°E faults as right-lateral (second order) shear and left-lateral (third order) shear, respectively. Due to the particular location of the Palinuro Seamount, the data presented here allow us to better understand the volcanism and the geodynamic processes of the Tyrrhenian Sea
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