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Dive into the research topics where Enrico Gallucci is active.

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Featured researches published by Enrico Gallucci.


Biophysical Journal | 2004

Effect of Sterols on β-Amyloid Peptide (AβP 1–40) Channel Formation and their Properties in Planar Lipid Membranes

Silvia Micelli; Daniela Meleleo; Vittorio Picciarelli; Enrico Gallucci

We investigate the role played by membrane composition on the interaction and self-assembly of b-amyloid peptide (AbP1-40) during pore formation in planar lipid membranes (PLMs). Incorporation studies showed that AbP does not interact with zwitterionic membranes made up of phosphatidylcholine, whereas the addition of cholesterol or ergosterol to the membranes leads to channel formation. Among the PLMs used, a higher propensity of AbP to form channels at low applied potential (620 mV) was observed in 7-dehydrocholesterol and in oxidized cholesterol PLMs. These channels present long lifetimes, high-occurrence frequencies, and are voltage dependent. In particular, the AbP channel in oxidized cholesterol showed anion selectivity. Thus cholesterol (and sterols in general) could be considered as targets for AbP, which prevents the fibrillation process by increasing incorporation into membranes. Furthermore, by switching the channel selectivity versus anions, cholesterol helps to reduce the imbalance of the cellular ions, calcium included, induced by membrane depolarization, which could be one of the factors responsible for cytotoxicity in Alzheimers disease.


Biophysical Journal | 2001

Channel formation by salmon and human calcitonin in black lipid membranes.

Valentina Stipani; Enrico Gallucci; Silvia Micelli; Vittorio Picciarelli; Roland Benz

In this study we investigated the interaction of salmon and human calcitonin (Ct) with artificial lipid bilayer membranes. Both peptides were able to form either transient or permanent channels in the model membranes. The channels formed by salmon Ct at concentration (125 nM) had, on average, a single-channel conductance of 0.58 +/- 0.04 nS in 1M KCl (+10 mV), which is voltage-dependent at lower voltages. Human Ct forms at the same concentration channels with a much lower probability, and high voltages of up to +150 mV were needed to initiate channel formation. The estimated single-channel conductance formed under these conditions was approximately 0.0119 +/- 0.0003 nS in 1 M KCl. Both salmon and human Ct channels were found to be permeable to calcium ions. The possibility is discussed that the superior therapeutic effect of salmon Ct as a tool to treat bone disorders, including Paget disease, osteoporosis, and hypercalcemia of malignancy, rather than human Ct is related to the lack of the fibrillating property of salmon Ct. Preliminary data indicate that also eel and porcine Ct and carbocalcitonin form channels in model membranes.


Journal of Peptide Science | 2008

Kissper, a kiwi fruit peptide with channel-like activity: structural and functional features.

M. Antonietta Ciardiello; Daniela Meleleo; Gabriella Saviano; Roberta Crescenzo; Vito Carratore; Laura Camardella; Enrico Gallucci; Silvia Micelli; Teodorico Tancredi; Delia Picone; Maurizio Tamburrini

Kissper is a 39‐residue peptide isolated from kiwi fruit (Actinidia deliciosa). Its primary structure, elucidated by direct protein sequencing, is identical to the N‐terminal region of kiwellin, a recently reported kiwi fruit allergenic protein, suggesting that kissper derives from the in vivo processing of kiwellin. The peptide does not show high sequence identity with any other polypeptide of known function. However, it displays a pattern of cysteines similar, but not identical, to those observed in some plant and animal proteins, including toxins involved in defence mechanisms. A number of these proteins are also active on mammalian cells. Functional characterization of kissper showed pH‐dependent and voltage‐gated pore‐forming activity, together with anion selectivity and channeling in model synthetic PLMs, made up of POPC and of DOPS:DOPE:POPC. A 2DNMR analysis indicates that in aqueous solution kissper has only short regions of regular secondary structure, without any evident similarity with other bioactive peptides. Comparative analysis of the structural and functional features suggests that kissper is a member of a new class of pore‐forming peptides with potential effects on human health. Copyright


European Biophysics Journal | 2003

Magainin 2 channel formation in planar lipid membranes: the role of lipid polar groups and ergosterol

Enrico Gallucci; Daniela Meleleo; Silvia Micelli; Vittorio Picciarelli

Abstract. Magainin 2, a polycationic peptide, displays bactericidal and tumoricidal activity, presumably interacting with negatively charged phospholipids in the membrane hosts. In this work, we investigate the role played by the lipid head-group in the interactions and self-association of magainin 2 during pore formation in lipid bilayers. Two methods are used: single-channel and macroscopic incorporation into planar lipid membranes. Single-channel incorporation showed that magainin 2 did not interact with zwitterionic membranes, while the addition of negatively charged dioleoylphosphatidylglycerol to the membrane leads to channel formation. On the other hand, magainin 2 did not form channels in membranes made up of dioleoylphosphatidylserine (DOPS), although the addition of ergosterol to DOPS membranes leads to channel formation. This finding could indicate that ergosterol may be a possible target of magainin 2 in fungal membranes. Further support for this hypothesis comes from experiments in which the addition of ergosterol to palmitoyloleoylphosphatidylcholine membranes induced channel formation. Besides the role of negatively charged membranes, this study has shown that magainin 2 also forms channels in membranes lacking heads, such as monoolein and oxidized cholesterol, indicating an interaction of magainin 2 with acyl chains and cholesterol, respectively. This finding provides further evidence that peptide binding and assembly in lipid membranes is a complex process driven by electrostatic and/or hydrophobic interactions, depending on the structure of the peptide and the membrane composition.


Bioelectrochemistry | 2002

Mitochondrial porin incorporation into black lipid membranes: ionic and gating contribution to the total current

Silvia Micelli; Enrico Gallucci; Daniela Meleleo; Valentina Stipani; Vittorio Picciarelli

We present a new ac device useful for simultaneous measurements of ionic charge movement (conductance) and gating charge displacement (capacitance) in mitochondrial porin channels incorporated in two kinds of black lipid membranes (BLMs), made up of phosphatidylinositol (charged surface) and oxidized cholesterol (neutral surface). In particular, we investigated the conductance/capacitance variations during the process of porin incorporation (VDAC) at different porin concentrations. While conductance variations are present throughout the porin concentration range investigated, a threshold value seems to be necessary in order to detect a significant capacitance variation. A clear steady state in both conductance and capacitance is reached for the phosphatidylinositol bilayer, while for the oxidized cholesterol membranes, the steady state is reached only for the conductance. The dependence of capacitance characteristics on the membrane applied voltage V(m) is investigated before porin incorporation and at the ionic current steady state. The results obtained confirm that before porin incorporation, there is a small dependence on V(m)(2), while afterwards we find evidence of a dual exponential voltage dependence (a result similar to that found for conductance). Finally, we investigated the capacitance dependence on the radius of the hole separating the two compartments of the cell used in the measurements. In this study, performed only with oxidized cholesterol, the radius was varied from 200 to 1050 microm. We observed a significant variation in the specific capacitance in particular for smaller radii. The results were interpreted by a simple geometrical model taking into account the influence of the torus.


Biochemical Pharmacology | 1984

Interaction of the aminoglycoside antibiotic dihydrostreptomycin with the H+-ATPase of mitochondria

Ferruccio Guerrieri; Silvia Micelli; Chiara Massagli; Enrico Gallucci; Sergio Papa

In this paper a study is presented of the effect of dihydrostreptomycin on the H+-ATPase of the inner mitochondrial membrane. The antibiotic caused at concentrations of 1-5 X 10(-3)M a marked enhancement of the hydrolytic activity of the H+-ATPase complex in intact mitochondria and submitochondrial particles which was accompanied, in the latter, by enhancement of passive transmembrane proton conduction by the complex. The stimulation by dihydrostreptomycin of ATP hydrolysis resulted in a suppression of the sensitivity of this activity to inhibition by oligomycin. On the other hand the dihydrostreptomycin-promoted proton conduction in submitochondrial particles was suppressed by oligomycin. At concentrations above 10(-2)M dihydrostreptomycin caused inhibition of the activity of both membrane bound and isolated H+-ATPase. In submitochondrial particles devoid of the catalytic moiety (F1) of the H+-ATPase complex, dihydrostreptomycin caused partial inhibition of proton conductivity. It is concluded that the antibiotic uncouples the hydrolytic activity of the catalytic moiety (F1) from transmembrane proton conduction by the membrane sector (F0) of the ATPase complex. This effect can be followed at higher concentrations of dihydrostreptomycin by inhibition of the catalytic activity of F1 and, when F1 is removed from the membrane, by inhibition of transmembrane proton conduction by F0.


Comparative Biochemistry and Physiology Part A: Physiology | 1983

Serosal and mucosal facilitated transport of urea in urinary bladder of bufo bufo evidence for an alleged water uptake

Silvia Micelli; C Massagli; Enrico Gallucci

In Bufo bufo urinary bladder an urea facilitated transport has been localised on the luminal membrane. The transport fulfils the criteria for such a mechanism, i.e. is saturable and is inhibited by phloretin, a specific inhibitor for urea transport. Similarly to that of Bufo marinus and Rana esculenta the luminal membrane of Bufo bufo urinary bladder shows an ADH stimulated facilitated transport. Experiments wtih Amphotericin B, serosal phloretin (with and without ADH), have demonstrated the presence of a facilitated urea transport localised on basolateral membrane. Urea uptake on the isolated epithelial cells of Bufo bufo urinary bladder shows a characteristic feature, different from molecules passively transported such as glycerol yet inhibited by phloretin. Allegedly with urea, water flows in to the cells by a dragging or osmotic effect.


The Open Nutraceuticals Journal | 2012

Studies on the Effect of Salts on the Channel Activity of Kissper, a Kiwi Fruit Peptide

Daniela Meleleo; Enrico Gallucci; Gabriella Notarachille; Cesare Sblano; Alessandra Schettino; Silvia Micelli

Fruits and vegetables are known to possess health benefits: indeed, they contain a large number of bioactive molecules with a positive impact on human health. Dietary proteins possess specific biological properties which make these components potential ingredients of functional or health-promoting foods. Many of these properties are attributed to physiologically-active peptides encrypted in protein molecules. Kissper, a 39-residue peptide isolated from kiwi fruit (Actinidia deliciosa), derives from the processing of kiwellin, a well-represented novel allergenic protein present in the edible part of the fruit. Kissper has six cysteine residues forming three disulfide bridges. This cysteine pattern is similar, but not identical, to those observed in some plant and animal proteins, including toxins involved in defence mechanisms. We show that kissper forms ion channels in DOPS:DOPE:POPC PLMs in different media, such as KCl, potassium gluconate, potassium citrate and potassium phosphate monobasic. Kisspers channels show a strong voltage dependence in all media used, and an estimated pore diameter in the range from 1.9 to 7.6 A in KCl medium. Finally, kisspers pores shift selectivity from anions to neutral to cations, depending on the nature of the salt solutions. Therefore we propose the kissper as a novel nutraceutical component of kiwi fruit that may have a positive impact on human health due to its channel-like pathways which modulate membrane permeability. The kissper action might promote the adsorption of substances, in particular, within the gastrointestinal tract, helping digestion, preventing constipation and harmful accumulation of metabolites.


Advances on Planar Lipid Bilayers and Liposomes | 2008

Chapter 7 A New Class of Peptide-Forming Channel: Calcitonins

Silvia Micelli; Daniela Meleleo; H. Ti Tien; Angelica Leitmannova Liu; Vittorio Picciarelli; Enrico Gallucci

Abstract Calcitonin is a small peptide hormone present in all vertebrates with an important effect on Ca 2+ metabolism. It exerts its main action by inhibiting osteoclast-mediated bone resorption and inducing calcium regulation through an interplay of clearance through the kidney and intestine. This action is responsible for its widespread clinical use in the treatment of bone disorders, including Pagets disease, osteoporosis, hypercalcemia of malignancy, and musculoskeletal pain. Unfortunately, this peptide (at least the human calcitonin, or hCt) shows a high tendency to aggregate, resulting in fibrillation that impairs its use as a drug for the above pathologies. This could explain why other calcitonins with a lower tendency to fibrillate, in particular salmon and eel calcitonin (sCt, eCt), are currently in use. The mechanism of fibrillation is common to other peptides such as insulin, prion protein, Alzheimer Aβ, and the α-synuclein responsible for Parkinsons disease, is far from being well understood despite the many investigations which have been undertaken. Thus, if the mechanism underlying the fibrillation of one peptide could be resolved, this may be extrapolated to the other fibrillating peptides, thus shedding light on the “channel pathologies” which are presumably linked by a common denominator. The technique used to study the fibrillation mechanism is performed both in solution and on the membrane surface. In fact, it has been found that membrane phospholipids can play an important role either inducing or counteracting aggregation by incorporating peptides into the membrane. In the past few years, we have been performing systematic studies using model Planar Lipid Membranes (PLM) in order to: • gather evidence of calcitonin incorporation into the membrane and channel formation under different experimental conditions (i.e., membrane applied voltage, bathing conditions); • test the influence on hCt channel properties of varying the PLM composition, or the pH of the medium, and of inducing and stabilizing α-helices by means of an anionic detergent; • understand the role of glycosylation at a different position in eCt during peptide incorporation and channel formation. The results obtained can be summarized as follows: • on the ability to form channels : hCt and sCt are able to form channels when incorporated into DOPC/DOPG (molar ratio 85:15) model membranes. Moreover, the average single-channel conductance decreases as a function of the membrane applied voltage (from ∼0.2/0.5 nS at ±10 mV for hCt and sCt, respectively, to ∼0.014 nS at ±150 mV for both) and has different values under different bathing conditions (higher for NaCl, CaCl 2 , KCH 3 COO than for KCl). The permeability for cations/anions is almost identical. Finally eel, porcine, and carbocalcitonin also form channels, with a mean conductance higher than that of hCt and sCt. • on the way in which the acid-base conditions in the bathing medium affect the hCt channels : At pH 7, hCt is able to interact and forms channels with negatively charged dioleoyl-phosphatidyl-glycerol (DOPG) bilayers and with zwitterionic palmitoyl-oleoyl-phosphatidylcholine (POPC) bilayers containing 15% negatively charged DOPG, but not with POPC bilayers. At low pH (4.4 and 3.8), the conformational variation of the peptide enables it to insert into POPC and POPC:DOPG but not into DOPG bilayers. • on the effect of detergent on the hCt channels : Sodium dodecyl sulfate (SDS) an anionic detergent able to induce and stabilize α-helices of polypeptides, at concentrations ranging between 0.26 mM and 5 pM [all concentrations are below the critical micelle concentration (CMC)] increases the rate and number of hCt channel formation in PLM at both high and low hCt concentration, with a maximum increase at a molecular hCt/SDS ratio of 1000:1. The action of SDS could be attributable to the strength of the sulfate negative charge and the hydrophobic chain; in fact a similar effect was obtained with lauryl sarcosine and not with a neutral detergent such as n -dodecyl-β- d -maltoside. • on the glycosylation at different positions in eCt : eCt glycosylation at different positions (Ct3-GlcNAc, Ct14-GlcNAc, Ct20-GlcNAc, and Ct26-GlcNAc) preserves the molecular structure and slightly changes the energy of incorporation and channel formation into POPC:DOPG (85:15 w/w). The voltage needed to form channels decreases as the attached carbohydrate moves toward the C-terminal (eCt = Ct3-GlcNAc > Ct14-GlcNAc = Ct20-GlcNAc > Ct26-GlcNAc). Interestingly, all the Cts tested maintain the characteristic voltage-conductance dependence found for other Cts; the only channel property modified being ion selectivity that shifts toward anion selectivity (eCt = 0.97, Ct3-GlcNAc = 0.49, Ct14-GlcNAc = 0.41, Ct20-GlcNAc = 0.36, and Ct26-GlcNAc = 0.47).


Journal of Pharmaceutical Sciences | 2004

Frog intestinal sac: A new in vitro method for the assessment of intestinal permeability†

Giuseppe Trapani; Massimo Franco; Adriana Trapani; Angela Lopedota; Andrea Latrofa; Enrico Gallucci; Silvia Micelli; Gaetano Liso

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Delia Picone

University of Naples Federico II

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