108 research outputs found
«Scusami gli errori ma in italiano non sono molto brava». Scrittura giovanile degli anni Sessanta e alfabetizzazione di massa in un corpus di lettere dell’Archivio di Gigliola Cinquetti
No full text(In A. Iuso - Q. Antonelli (a cura di), Scrivere agli idoli. La scrittura popolare negli anni Sessanta e dintorni a partire dalle 150.000 lettere a Gigliola Cinquetti)
Fedeltà e identità: etica e/o ontologia? “Pensare altrimenti” con Ricoeur a partire dalla fedeltà
No full textPartendo da una lettura del pensiero di Paul Ricoeur sul tema della fedeltà si tenta (1) l’elaborazione di una fenomenologia della fedeltà, individuandone la forma positiva e le forme degenerate. Alla luce di questo (2) si delinea la struttura di fondo del fenomeno della fedeltà autentica (l’apertura all’alterità) e i presupposti metafisici a livello globale di concezione della realtà (ontologia dinamica e dell’atto contro un’ontologia statica dell’ente). Infine (3) si avanzano alcune questioni metafisiche poste in gioco dalla fedeltà: sul piano ontologico (ontologia dinamica), sul piano antropologico (verità nella libertà), sul piano teologico (fedeltà/tradimento nella relazione con Dio). In conclusione si evidenzia che la questione della fedeltà comporta una ridefinizione della nozione di identità, in particolare dell’identità personale umana caratterizzata dalla stretta connessione di essere e libertà, dato e compito, ontologia ed etica.Taking the view of Paul Ricoeur on fidelity as a point of departure, the author tries to resolve the issue as follows.
First, by elaborating a phenomenology of fidelity identifying its positive form as well as degenerated form.
Secondly, consequent upon the above assertion, the article tries to show the basic structure of authentic phenomenon of fidelity (openness to alterity) and the metaphysical premises at a global level of conceiving reality (dynamic ontology of the act against a static ontology of being).
Thirdly, some metaphysical questions on fidelity are considered, with focus on the ontological realm (dynamic ontology), on anthropological realm (truth in liberty) and on theological realm (fidelity/betrayal in relationship with God).
In conclusion, it is highlighted that the question on fidelity comprises a redefinition of the notion of identity, especially of the personal human identity characterized by the close connection between being and freedom, fact and task, ontology and ethics
Immaginare il bene. Paul Ricoeur e l’etica tra fiducia nel bene originario e speranza nella vita buona
No full textL’intento dell’intervento è duplice: (a) in una prima parte di carattere sintetico si cerca di dare una visione per quanto possibile complessiva e globale del ruolo dell’immaginazione in Ricoeur delineando una “mappa dell’immaginazione ricoeuriana”; (b) nella seconda parte di carattere più analitico ci si concentra sull’aspetto etico per esplicitare le procedure che Ricoeur ha cercato di mettere in atto per rendere più abitabile il mondo mediante l’immaginazione produttiva: ci si sofferma dunque su alcune categorie etiche elaborate da Ricoeur, legate all’immaginazione, quali il binomio ideologia/utopia (sul piano dell’ethos sociale-collettivo) e l’ambito della saggezza pratica (sul piano dell’etica riflessa) con tutte le sue variazioni (dialettica di giustizia e amore, compromesso, traduzione, giustizia restauratrice, perdono, mutuo riconoscimento).The article has a double aim: (a) in a first synthetic part it searches to give a comprehensive overview of the role of imagination in Ricoeur’s thought and it draws a “map of ricoeurian imagination”; (b) in a second analytical part it underlines ethical aspect in order to explain the different ways that Ricoeur tried to follow to make the world more liveable trough creative imagination: it focuses on some Ricoeur’s ethical categories, linked to imagination, such as ideology/utopia (on the side of social ethics) and practical wisdom (on the side of theoretical ethics) with all its connections (dialectic of justice and love, compromise, translation, restorative justice, forgiveness, mutual recognition)
The invertebrate transporters of SLC6 family are able to transport D-amino acid
No full textNeutral amino acids, which predominantly represent essential substrates in animals, are absorbed via a B0 transport system (the Broad neutral amino acid system). Molecular and phylogenetic analysis of insect SLC6 members revealed a Nutrient Amino Acid Transporters (NATs) cluster that is phylogenetically close to mammalian B0 transporters and that can be classified in SLC6 Family. Differently from the mammalian and fish orthologs, these insect proteins can transport D-amino acids. Since their cloning, the Manduca sexta neutral amino acid cotransporter KAAT1 (K+-coupled amino acid transporter 1) and its homologous CAATCH1 (cation anion activated amino acid transporter/channel 1) have represented a useful tool for investigation in structure function because of unique physiological features. In presence of D- isomers of leucine, serine and proline, the msKAAT1, when heterologously expressed in Xenopus laevis oocytes, generates inward, transport-associated, currents with variable relative potencies, depending on the driving ion Na+ or K+. msCAATCH1 is also able to transport the D-amino acids tested, including D-leucine, while L-leucine acts as a blocker. A similar behavior is exhibited by the KAAT1 mutant S308T, confirming the relevance of this residue in L-leucine binding and the different interaction of D-leucine. Instead, the residue T67 that it is present as threonine only in KAAT1 and the paralogue CAATCH1, when mutated in tyrosine increased the stereoselectivity for L-isomers in KAAT1. T67 it is not conserved among SLC6 family members but according to LeuT structure organization, coordinates the organic substrate.
D-leucine and D-serine on various vertebrate orthologs B0AT1 (SLC6A19) elicited only a very small current, indicating that transport of D isomers it is specific of the insect neutral amino acid transporters. These findings highlight the relevance of D-amino acid absorption in the insect nutrition and metabolism and may provide new evidences in the molecular transport mechanism of SLC6 family
«Nonostante» e «molto di più». Ricoeur tra fede filosofica e fede religiosa
No full textL’articolo cerca di mettere in evidenza la presenza nel pensiero di Ricoeur di questa forte e ostinata dimensione fiduciale che si esprime in termini ambivalenti: da un lato come una sorta di fede filosofica di jaspersiana memoria, dall’altro attraverso la più volte dichiarata e mai nascosta fede religiosa in Dio, e in specie nel Dio di Gesù Cristo. Si tratta in sede di conclusioni (1) di abbozzare il tipo di razionalità filosofica che sottende questa dimensione fiduciale e (2) di capire la relazione tra le due forme di fede (filosofica e religiosa), una relazione che lascia aperte sfide nuove per la filosofia della religione e la teologia delle religioni
Paul Ricoeur e il decentramento del Cogito. La “questione del soggetto” in Le conflit des interprétations
No full textAttraverso i saggi contenuti in Le conflit des interprétations (1969) Ricoeur, dopo essere approdato alla fenomenologia-ermeneutica, si confronta in una «conflittualità costruttiva» con Freud e Hegel, Husserl, Heidegger, lo strutturalismo, la filosofia riflessiva francese. Lo studio mette in luce il duplice rapporto critico ma anche costruttivo che Ricoeur insatura con questi autori. Punto di approdo finale è la messa in questione del soggetto puro e idealista a favore di un soggetto decentrato e ferito, ma non annullato, caratterizzato dalla priorità dell’io sono sull’io penso
Intracellular ANKRD1 protein levels are regulated by 26S proteasome-mediated degradation
No full textAbstractThe ANKRD1/CARP gene encodes a muscle-specific protein which has been implicated in transcriptional regulation and myofibrillar assembly. Several features at both the mRNA and protein levels define ANKRD1 as a gene whose expression is tightly regulated, and deregulated expression of this protein has been recently associated to human congenital heart disease. It is therefore crucial to define the intracellular pathways that regulate the ANKRD1 protein’s steady-state levels. Here, we show that ANKRD1 is a short-lived protein whose levels are tightly regulated by the 26S proteasome. In addition, a critical role for a putative PEST motif was established, although other degrons within the ANKRD1 protein are likely implicated in the control of its intracellular levels
Comparison of the electrophysiological properties of the two paralogues of Salmo salar oligopeptide transporter PepT1: new insights from PepT1a vs. PepT1b
No full textDi and tripeptide (di/tripeptide) absorption in the intestine occurs via PepT1, an electrogenic transporter that uses an inwardly-directed proton electrochemical gradient to drive the transport of more than 8,000 different molecules inside the cells. Studies in mammals indicate that PepT1 also exhibits peptide sensing function(s). In teleost fish, two genes, namely PepT1b and more recently PepT1a, have been identified. The two paralogues – the result of (at least one) round of whole-genome duplication during the early evolution of the ray-finned fish lineage – encode proteins that share 64-67% similarity at the amino acid level. While PepT1b has been widely studied in several teleost fish species, including S. salar, PepT1a function is fully unknown to date. The aim of this work was to characterize and compare S. salar PepT1a and Pept1b after heterologous expression in Xenopus laevis oocytes, and study their role(s) in peptide transport and/or sensing. Injection of cRNAs into X. laevis oocytes allowed high functional “in membrane” expression of both proteins. Function was verified by Two Electrode Voltage Clamp (TEVC), as currents elicited by perfusion of di/tripeptides were regularly recorded for both proteins. Notably, ours is the first experimental evidence that PepT1a is an electrogenic transporter of di/tripeptides. Measuring the transport currents at two different pH (6.5 and 7.6) and in the presence of increasing concentrations of glycine-L-glutamine (GQ) (from 0.01 to 30 mM) allowed to investigate kinetic values, as the maximal current (Imax) and the substrate apparent affinity (K0.5), for each transporter and pH. Results suggest that the two transporters interact differently with the substrate and that the external pH influence the substrate affinity and consequently the transport efficiency, which is definitely lower for PepT1a with respect to PepT1b. Moreover, preliminary results suggest that L-lysine-containing substrates elicit transport-associated currents of different amplitude in the two isoforms. Large currents are recorded from PepT1b in the presence of L-lysine-glycine (KG), and currents similar to GQ are recorded for glycine-L-lysine (GK); conversely, small responses for both substrates are obtained in PepT1a. Overall, these data support the idea of a different role of the two isoforms, opening the possibility to investigate on PepT1a as a “transceptor” involved in nutrient sensing.
Daniel, H. & Zietek, T. Experimental physiology 100, 1441-1450, (2015).
Diakogiannaki, E. et al. Diabetologia 56, 2688-2696, (2013).
Romano, A., Barca, A., Storelli, C. & Verri, T. J.Physiol 592, 881-897 (2014).
Ronnestad, I. et al. J.Nutr. 140, 893-900 (2010).
Sangaletti, R. et al. Pflugers Arch. (2009)
Caratterizzazione Molecolare della traslocazione t(10;21) in un paziente affetto da Ritorno Venoso Polmonare Anomalo Totale (TAPVR)
No full textThreonine 67 is a key component in the coupling of the NSS amino acid transporter KAAT1
No full textThe crystallizations of the prokaryotic LeuT and of the eukaryotic DAT and SERT transporters represent important steps forward in the comprehension of the molecular physiology of Neurotransmitter: Sodium Symporters, although the molecular determinants of the coupling mechanism and of ion selectivity still remain to be fully elucidated. The insect NSS homologue KAAT1 exhibits unusual physiological features, such as the ability to use K+ as the driver ion, weak chloride dependence, and the ability of the driver ion to influence the substrate selectivity; these characteristics can help to define the molecular determinants of NSS function. Two non-conserved residues are present in the putative sodium binding sites of KAAT1: Ala 66, corresponding to Gly 20 in the Na2 site of LeuT, and Ser 68, corresponding to Ala 22 in the Nal site. Thr 67 appears also to be significant since it is not conserved among NSS members, is present as threonine only in KAAT1 and in the paralogue CAATCH1 and, according to LeuT structure, is close to the amino acid binding site. Mutants of these residues were functionally characterized in Xenopus oocytes. The T67Y mutant exhibited uptake activity comparable to that of the wild type, but fully chloride-independent and with enhanced stereoselectivity. Interestingly, although dependent on the presence of sodium, the mutant showed reduced transport-associated currents, indicating uncoupling of the driver ion and amino acid fluxes. Thr 67 therefore appears to be a key component in the coupling mechanism, participating in a network that influences the cotransport of Na+ and the amino acid
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