728 research outputs found
Post tectonic growth of late diagenetic greigite
No full textPaleomagnetic, rock magnetic and micro-textural
analyses from a Middle Pleistocene lacustrine sequence
in the southern Apennines (Italy) indicate the presence of
greigite and magnetite as the main magnetic minerals at
different stratigraphic levels. In all cases a normal polarity
characteristic remanent magnetization (ChRM) was observed,
in agreement with an 40Ar–39Ar age of 0.712 ± 0.018 Ma
from volcaniclastic sanidine. After correction for bedding tilt,
ChRM directions carried by greigite do not coincide with the
expected geocentric axial dipole field direction at the site
latitude, whereas the magnetite ChRMs directions do. The
data indicate that the greigite magnetization was acquired
after tilting and after lock-in of the magnetite ChRM.
The estimated delay for the remanence carried by greigite
with respect to deposition is 300 ka. Scanning electron
microscope analyses indicate that alteration of detrital
volcanic minerals has occurred and that authigenic greigite
is generally present in agglomerates and around volcanic
grains. This observation is consistent with a late diagenetic
origin of greigite due to anoxic conditions and availability of
dissolved sulfide associated with decomposition of organic
matter in the paleolake. Documentation of a late diagenetic
magnetization confirms that care should be taken when
using greigite-bearing sediments for magnetostratigraphic
and tectonic studies. Citation: Porreca, M., M. Mattei, and
G. DiVincenzo (2009), Post-deformational growth of late diagenetic
greigite in lacustrine sediments from southern Italy
"Dalla guerra di Suez all'attentato di Bascapé: l'ombra di Israele sul 'caso Mattei'"
No full textIl libro in cui è inserito il saggio di Claudio Moffa raccoglie contributi dalle iniziative e lezioni del MASTER ENRICO MATTEI IN MEDIO ORIENTE dell'Università di Teramo, creato e diretto dallo stesso Moffa dal 2005 fino ad oggi 2012. In particolare nel libro sono stati pubblicati la Prolusione di Giulio Andreotti al Master, 6 febbraio 2006, e gli atti del convegno "Enrico Mattei, il coraggio e la Storia" del maggio 2006. La relazione di Moffa, basata su una ricerca negli archivi dell'ENI di Pomezia, portava alla luce alcuni documenti inediti ella vicenda Mattei (in fotocopia tra le pagine del saggio), che evidenziano la centralità della "questione Israele" nella politica di cooperazione con Nasser e il mondo arabo voluta da Mattei. Un dato tutto sommato "scontato" (all'epoca il conflitto tra lo Stato ebraico e tutto il mondo arabo era più netto e acuto di quanto non lo sia oggi) ma per la prima volta comprovato da interessanti documenti di archivio, utili a superare la marginalizzazione e l'oblio della questione che essi sollevano, da parte di numerosa saggistica su Enrico Mattei[...
Bibliografia di Umberto Romagnoli
No full textA complete bibliography of Umberto Romagnoli writings, introduced by a few lines by editors of the Journal and completed by an essay by Alberto Mattei dealing with some technical aspects of the collection of the
bibliography interwoven with some scholarly life moments of the author
10th Anniversary of Biomedicines—Advances in Mesenchymal Stem Cells
No full textMesenchymal stromal cells (MSCs) are non-specialized adult stem cells (ASCs), cells that reproduce to provide specific cytotypes [...
Dental Pulp Stem Cells (DPSCs) and Tissue Regeneration: Mechanisms Mediated by Direct, Paracrine, or Autocrine Effects
No full textAmong mesenchymal stem cells, dental pulp stem cells (DPSCs) were discovered most recently [...
Cellular prion protein associates with a multimolecular complex including LRP1 and glycosphingolipids within lipid rafts
No full textPlasma membrane of different cell types contains microdomains, commonly referred to as lipid rafts (Simons and Ikonen, 1997). These domains are enriched in sphingolipids and cholesterol, moreover a number of proteins involved in signal transduction pathways co-purify with lipid rafts isolated on sucrose gradient (Langlet et al., 2000; Anderson et al., 2000). Like other GPI-anchored proteins, the evidence for the involvement of lipid rafts in the localization and trafficking of PrPc, as well as in PrPc-mediated cellular signaling, has been reported in neuronal and non neuronal cells (Mattei et al., 2002; Mattei et al., 2004; Lewis and Hooper, 2011).
It has been suggested that Low density lipoprotein receptor-related protein (LRP1), which is a member of the LDL receptor gene family (Strickland et al., 2002) and controls both, the surface and biosynthetic trafficking of PrPc in neurons (Parkyn CJ et al. 2007), is the central organiser, but not the sole functional component, of a larger complex that traffics PrPc during biosynthesis and at the cell surface. LRP1 functions as an endocytic receptor for a broad range of structurally and functionally diverse ligands and also functions in cell signaling, directly, in response to ligand-binding, and indirectly, by regulating levels of other signaling receptors. We demonstrated that LRP1-initiated cell signaling is ligand-dependent. Proteins that activate cell signaling by binding to LRP1 assemble different co-receptor systems. Ligand-specific co-receptor recruitment provides a mechanism by which one receptor, LRP1, may trigger different signaling responses. (Mantuano et al., 2013). We hypothesized that the ability of PrP to induce cell signaling might involve a multi receptor complex, in which LRP1, in association with other receptors like TrkA receptor, plays a role in signal transduction within lipid rafts.
In this report we demonstrated that cellular prion protein is strictly associated with gangliosides in microdomains of SK-N-BE2. PrPC was present in the Triton-insoluble fractions, corresponding to lipid rafts of cell plasma membrane. In addition scanning confocal microscopical analysis revealed a consistent colocalization between PrPC and GM1, and TLC immunostaining, showed that PrPC was associated with GM1 in PrPC immunoprecipitates. Moreover, signal transduction experiments on neuritogenic Erk pathway were performed using recombinant PrP (PrPrec). The results indicated that PrP signals through the lipid raft and that PrP-mediated Erk1/2 phosphorylation is regulated by LRP1, confirming that the multimolecular complex plays a role in signal trasduction within lipid rafts. Taken together, these findings demonstrate that LRP1 associates with a multimolecular complex, including PrPc and ganglioside GM1, which is dependent on the integrity of lipid raft and is involved in the neuritogenic signaling and trafficking
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