2,886 research outputs found
Studio e sviluppo di sistemi fisico-computazionali per l’analisi distribuita di immagini biomediche
No full textSi tratta di un progetto PRIN finanziato dal MIUR nel biennio 2005-2006
e concernente la messa a punto di sistemi di supporto alla diagnosi di immagini mammografiche e polmonari.
Al progetto hanno partecipato le sedi di Bari, Genova, Pisa, Palermo, Sassari e il gruppo collegato di Lecce. Responsabile nazionale era il prof. Bellotti (Università di Bari). Il dott. De Miti era il coordinatore del gruppo collegato leccese
Antiquitates Italicae Medii Aevi, sive, Dissertationes de moribus, ritibus, religione, regimine, magistratibus, legibus, studiis literarum, artibus, lingua, militia, nummis, principibus, libertate, servitute, foederibus, aliisque faciem & mores Italici populi referentibus post declinationem Rom. Imp. ad annum usque MD : omnia illustrantur et confirmantur ingenti copia diplomatum et chartarum veterum, nunc primùm ex archivis Italiae depromtarum, additis etiam nummis, chronicis, aliisque monumentis nunquam antea editis /
No full textOccasional woodcut ill. depicting coins, monograms, inscriptions. Initials, head-pieces.Printed in double columns.Vols. 16-17 have imprint: Arretii, Typis viduae olim Michaëlis Bellotti impress. episc. sub signo Petrarcae.Date precedes printer on t.p.'s.Mode of access: Internet.Signature of R.H. Wilde, v. 3 & 4.Bound in 17 vols. in coarse gray paper, backed in vellum. Author, title and vol. no. written at head of spine. Edges roughly trimmed
Simultaneous Observation Of Extensive Air Showers And Deep Underground Muons At The Gran Sasso Laboratory
No full textSupport Vector Machines for Credit Scoring and discovery of significant features
No full textThe assessment of risk of default on credit is important for financial institutions. Logistic regression and discriminant analysis are techniques traditionally used in credit scoring for determining likelihood to default based on consumer application and credit reference agency data. We test support vector machines against these traditional methods on a large credit card database. We find that they are competitive and can be used as the basis of a feature selection method to discover those features that are most significant in determining risk of default
Study of Cu(II) and Zn(II) interaction with the metal binding domain of ZinT protein
No full textUnderstanding the mechanism of metal trafficking at the host/pathogen interface can help designing innovative antibiotic therapies. In fact, bacteria rely on sophisticated systems (e.g. metallophores) to sequester metals from the host environment during infections. In the attempt to investigate these metal-acquisition processes, we studied the complexation of Cu(II) and Zn(II) – two endogenous and competing metal ions – with some peptide fragments of ZinT, a periplasmic protein found in several bacterial species and mostly involved in Zn(II) recruitment. Its most probable metal-binding site corresponds to a domain containing three histidine residues (positions 167, 176 and 178) and one aspartic acid (position 166, Fig. 1). ZinT also possesses a highly conserved histidine-rich loop (HGHHXH, residues 124-129), whose participation in metals uptake has also been suggested [1,2].
By means of ESI-MS, potentiometry, UV-Vis/CD spectrophotometry and EPR measurements, we studied the formed metal complexes with the protected peptides Ac-124HGHHSH129-Am and Ac-166DHIIAPRKSSHFH178-Am (of ZinT sequence from Escherichia coli), and Ac-124HGHHAH129-Am and Ac-166DHIIAPRKSAHFH178-Am (ZinT-Salmonella enterica). We ultimately compared ZinT with some human-defence mediators, e.g. the antimicrobial peptide Calcitermin [3], to evaluate the metal effectiveness in the expression of the pathogenic/antimicrobial activity by the studied systems.
[1] A. Ilari, F. Alaleona, G. Tria, P. Petrarca, A. Battistoni, and C. Zamparelli, Biochim. Biophys. Acta. 1840(1) (2013) 535–544.
[2] P. Petrarca, S. Ammendola, P. Pasquali, and A. Battistoni, J. Bacteriol. 192(6) (2010) 1553–1564.
[3] D. Bellotti, M. Toniolo, D. Dudek, A. Mikolajczyk, R. Guerrini, A. Matera-Witkiewicz, M. Remelli, and M. Rowinska-Zyrek, Dalton Trans. 48(36), (2109) 13740–13752
The impact of metal coordination on calcitermin antimicrobial properties
No full textCalcitermin (VAIALKAAHYHTHKE) is a 15-mer antimicrobial peptide found in human nasal fluid [1] which is of particular interest thanks to its metal chelating ability. Noteworthy, it exhibits improved antifungal (C. albicans) and antibacterial properties in the presence of Zn2+ and Cu2+ ions under acidic conditions, while the histidine-to-alanine mutation in position 9, 11 and 13 can modulate the activity against certain microorganisms [2].
In light of the above, we decided to extend the study to other calcitermin derivatives, where the amino acid sequence is modified to understand the impact of metal coordination on the antimicrobial activity. The new synthetised derivatives include the C- and/or N- terminal protected peptides, which could also decrease the susceptibility towards exopeptidases, the alanine-to-serine mutants (A7S, A8S and A7/8S), which are designed to stabilize copper complexes [3] and the truncated analogue Ac-AHYHTHKE-NH2 to verify if the metal coordination site of natural calcitermin can correspond to the minimum active sequence.
This work is therefore aimed at characterizing the interaction of Zn2+ and Cu2+ ions with calcitermin derivatives in aqueous solutions. A deep investigation of the thermodynamic parameters of complex formation equilibria and of the coordination chemistry of the formed species has been obtained by means of several techniques, including potentiometry, high-resolution mass spectrometry, UV-Vis, circular dichroism and EPR.
Financial support of the Polish National Science Centre (UMO-2020/37/N/ST4/03165) and of the COST Action CA18202, NECTAR – Network for Equilibria and Chemical Thermodynamics Advanced Research is gratefully acknowledged.
[1] M. Cole, Y.-H. Kim, S. Tahk, T. Hong, P. Weis, A.J. Waring, T. Ganz, T. FEBS Lett 504 (2001) 5-10.
[2] D. Bellotti, M. Toniolo, D. Dudek, A. Mikołajczyk, R. Guerrini, A. Matera-Witkiewicz, M. Remelli, M. Rowińska-Żyrek, Dalton Trans. 48 (2019) 13740-13752.
[3] D. Bellotti, A. Miller, M. Rowińska-Żyrek, M. Remelli, Biomolecules 12 (2022) 121
Calcitermin and its peptide derivatives as promising antimicrobial agents with metal chelating ability
No full textThanks to the broad spectrum of activity and scarce attitude to induce antimicrobial resistance, antimicrobial peptides (AMPs) represent a rational chance to overcome the current drug-resistance crisis. Among several uncharacterized molecules that contribute to the overall antimicrobial activity of human nasal fluid, a 15-residue antimicrobial peptide named calcitermin (VAIALKAAHYHTHKE) has been identified [1]. Calcitermin contains a metal-binding domain with three alternated histidine residues (His9, His11 and His13) and the free terminal amino and carboxyl groups (Figure 1). It also exhibits an improved microbicidal activity when Zn2+ or Cu2+ ions are present in the culture medium [2]. Additionally, calcitermin His-to-Ala mutants – where each histidine residue is replaced with one alanine – have different metal coordination modes, resulting in significant changes of the antimicrobial properties. These results prompted us to focus on calcitermin derivatives where the peptide structure is modified to confer higher proteolytic stability but maintaining the metal chelating ability. Therefore, C- and/or N- terminal modifications have been introduced to possibly obtain calcitermin derivatives resistant to proteases [3]. Changes in the peptide backbone can affect the metal-binding behaviour and therefore further investigations on Zn2+ and Cu2+ interaction with calcitermin analougues are required to connect the antimicrobial activity with the complex-formation ability. The characterization of metal complexes has been performed by means of several techniques, including potentiometry, high-resolution mass spectrometry, UV-Vis, circular dichroism, NMR and EPR. The obtained results will allow us to propose and design new therapeutic antimicrobial strategies based on calcitermin derivatives and their metal complexes. Financial support of the Polish National Science Centre (UMO-2020/37/N/ST4/03165) is gratefully acknowledged.
References
[1] Cole, A. M., Kim, Y.-H., Tahk, S., Hong, T., Weis, P., Waring, A. J., Ganz, T. Calcitermin, a novel antimicrobial peptide isolated from human airway secretions. FEBS Lett., 504 (2001) 5-10.
[2] Bellotti, D., Toniolo, M., Dudek, D., Mikołajczyk, A., Guerrini, R., Matera-Witkiewicz, A., Remelli M., Rowińska-Żyrek, M., Dalton Trans., 48 (2019) 13740-13752.
[3] Vlieghe, P., Lisowski V., Martinez J., Khrestchatisky M. Synthetic therapeutic peptides: science and market. Drug Discov. Today, 15 (2010) 40-56
Unrevealing the antimicrobial properties of calcitermin and its peptide derivatives
No full textThanks to the broad spectrum of activity and scarce attitude to induce antimicrobial resistance, antimicrobial peptides (AMPs) represent a rational chance to overcome the current drug-resistance crisis. Among several uncharacterized molecules that contribute to the overall antimicrobial activity of human nasal fluid, a 15-residue antimicrobial peptide named calcitermin (VAIALKAAHYHTHKE) has been identified [1].
Calcitermin contains a metal-binding domain with three alternated histidine residues (His9, His11 and His13) and the free terminal amino and carboxyl groups. Based on our preliminary studies, it exhibits an improved microbicidal activity when Zn2+ or Cu2+ ions are present in the culture medium. Additionally, calcitermin His-to-Ala mutants – where each histidine residue is replaced with one alanine – have different metal coordination modes, resulting in significant changes of the antimicrobial properties [2].
These promising results prompted us to focus on calcitermin derivatives where the peptide structure is modified in order to confer higher proteolytic stability. The first task of this work consists of a careful evaluation of the enzymatic stability of native calcitermin in human plasma. Afterwards, C- and/or N- terminal modifications have been introduced to possibly obtain calcitermin derivatives resistant to proteases [3]. Changes in the peptide backbone, and in particular the N-terminus protection, can affect the calcitermin metal-binding behaviour and therefore further investigations on the metal interaction with the synthesized protected peptides have been performed, in order to connect the antimicrobial activity of calcitermin with the complex-formation ability. The characterization of metal complexes has been performed by means of several techniques, including potentiometry, high-resolution mass spectrometry, NMR, UV-Vis, circular dichroism and EPR. The obtained results will allow us to propose and design new therapeutic antimicrobial strategies based on calcitermin derivatives and their metal complexes.
Financial support of the Polish National Science Centre (UMO-2020/37/N/ST4/03165) and of the COST Action CA18202, NECTAR – Network for Equilibria and Chemical Thermodynamics Advanced Research is gratefully acknowledged.
[1] M. Cole, Y.-H. Kim, S. Tahk, T. Hong, P. Weis, A. J. Waring, and T. Ganz, FEBS Lett. 504 (2001) 5-10.
[2] D. Bellotti, M. Toniolo, D. Dudek, A. Mikołajczyk, R. Guerrini, A. Matera-Witkiewicz, M. Remelli, and M. Rowińska-Żyrek, Dalton Trans. 48 (2019) 13740-52.
[3] X. Lai, J. Tang, and M. E. H. ElSayed, Expert Opin. Drug Discov. (2021) 1-16
Dalla collezione di un artista a quella di un antiquario. Da Guglielmo Cortese (1679) a Giacomo Bellotti (1792)
No full textLa mia proposta vuole analizzare i passaggi ereditari della famiglia Cortese-Bellotti, dalla morte del pittore Guillaume Courtois (1679) fino alla morte del nipote Giacomo Bellotti (1792). Utilizzando materiale edito (il testamento di Guglielmo Cortese, R. Benucci, 2001) ed inedito (i testamenti di Margherita Cortese e Giacomo Bellotti, figlia e nipote del pittore francese), analizzerò quali dipinti sono passati in eredità, quali sono spariti dall’asse ereditario alla fine del XVIII secolo e quali sono andati a « sostituirli » nella collezione di famiglia. Guillaume Courtois (1628 – 1679), allievo di Pietro da Cortona, lascia in eredità alla moglie Felice Renzi tutti gli oggetti e le opere a lui appartenute. Tra queste figurano dipinti (a maggioranza non finiti), bozzetti, disegni, calchi in gesso etc. prevalentemente di mano dell’artista e solo alcuni dipinti e disegni di altri artisti (Brueghel, Ferdinand Voet, un Correggio, un Mola, un Sacchi..). Felice Renzi decide di mantenere intatta la « collezione » che si era venuta a formare con lo scopo di creare la dote per l’unica figlia rimasta della coppia, Margherita. Guglielmo era stato legato alla famiglia dei Borghese per diverso tempo, famosa è la pala di Monte Porzio commissionata dalla famiglia all’artista borgognone. Il legame con la famiglia Borghese e la dote paterna, garantiscono a Margherita un buon matrimonio poiché sposa nel 1702 Antonio Bellotti, maestro di Camera della famiglia romana. Tutta la famiglia Bellotti, compreso anche il fratello di Antonio, Francesco, vivranno nel Palazzo Borghese per decenni. Nel 1744, Margherita muore lasciando la sua eredità ai figli : i dipinti di Guglielmo Cortese, a maggioranza conservati da Margherita, passano dunque al di lei figlio Giacomo (1708-1792). Questi, a sua volta legato alla famiglia Borghese come maestro di Casa, si dedica con passione all’antiquaria, di moda nel XVIII secolo . Cambiano i gusti collezionistici tanto che nel suo inventario Giacomo conserva pochissimi dipinti provenienti dall’eredità Cortese, al loro posto spiccano dipinti o copie di altri autori, quali il Padovanino e il Benefial
- …
