Browsing by Author "Gabriele, Bartolo"

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Advanced mass spectrometry-based strategies for the isolation and characterization of G protein-coupled estrogen receptor 1(GPR)
(2014-11-28) Thangavel, Hariprasad; Gabriele, Bartolo; Sindona, Giovanni; Napoli, Anna
Estrogen signaling plays a vital role in breast, ovarian and endometrial cancers. The actions of estrogen are mainly mediated by classical estrogen receptors, ERα and ERβ that belongs to the nuclear receptor superfamily. In recent years, a class of membrane-associated estrogen receptors are found to mimic the functions of classical ERs, including genomic as well as non-genomic signaling. These non-genomic signaling events include pathways that are usually thought of as arising from transmembrane growth factor receptors and G protein-coupled receptors (GPCRs). GPCRs belong to a superfamily of cell surface signaling proteins. GPCRs represent the most significant family of validated pharmacological targets in medical biology. A member of the GPCR family, named GPER, mediates rapid biological responses to estrogen in diverse normal and cancer cells, as well as transformed cell types. The identification and characterization of GPER will lead to understand the mechanisms underlying complex biological pathways and identify potentially new drug targets. Here, we proposed a novel gel-free method to isolate and enrich GPER from crude lysate using home-made hydroxyapatite column (HTP). The HTP eluate was subjected to cellulose acetate (CA) filteration, followed by on-membrane protein digestion with different proteases and analyzed by MALDI MS. GPER was identified by peptide mass fingerprinting (PMF) after intensive data analysis. Sequence analysis reports 3 potential N-glycosylation in GPER. We manually validated 2 out of 3 glycosylation sites in GPER from the obtained MS/MS data and also validated the glycan moieties predicted by Glycomod. This approach is the first of its kind to identify GPER and characterize post-translational modifications (PTMs) by MS-based proteomic analysis. The proposed method is simple, robust and unique with great reproducibility. Finally, we designed and synthesized polymer nanoparticles (NPs) in an effort to capture GPER with high affinity and selectivity from crude lysate. PNIPAm-based NPs were synthesized by a free radical precipitation polymerization method with no control over the functional monomer sequence. The NP binding affinity was evaluated against both truncated-GPER (short peptide epitopes) and GPER (whole protein). As the NPs were designed with complementary functionality against the peptides/protein, the NPspeptide/ protein binding will be through multipoint interactions. The initial qualitative results obtained by immunoblotting analysis revealed interesting hints on GPER’s competitive affinity towards NPs when probed against multiple antibodies. We anticipate to use this strategy as a sample purification step prior to MS-based proteomic analysis
Amino function and side chain modifications of amino acids, and synthesis of thrombin inhibiting peptides
(2008-10-07) Viscomi, Maria Caterina; Liguori, Angelo; Gabriele, Bartolo
Design and quality control of drugs of natural and synthetic origin
(2010) Oliverio, Filomena; Ragno, Gaetano; Gabriele, Bartolo
Design, synthesis and characterization of suitable nitrones for several synthetic applications
(2013-11-21) Melicchio, Alessandro; Bartolino, Roberto; Gabriele, Bartolo; Maiuolo, Loredana
The present work takes advance of nitrone chemistry flexibility in order to synthesize, on one hand, bisphosphonates containing N,O-carbocyclic nucleoside units with potential biological activity, starting from nitrones with functionalizable ester or methylen bisphosphonated groups. On the other hand, to synthesize suitable allyl cyclic nitrones undergoing 2-aza-Cope rearrangement in order to study the [3,3]-sigmatropic process that has been rarely detected until now with neutral molecules which are nitrones. The synthetic strategy that we used for the bisphosphonates compound involves the synthesis of suitable nitrones and subsequently 1,3-dipolar cycloaddition reaction between these substrates and various vinyl nucleobases that carries at formation of isoxazolidinyl nucleosides. We decided to synthesize them for their significant pharmacological properties that make them very appealing: they showed a considerable cytotoxic activity against several human cell lines and therefore they could be successfully employed as anticancer drugs. Furthermore, bisphosphonates can be considered as stable analogs of pyrophosphate, that is implied in the physiological regulation of bone calcification and resorption. Moreover, during the staying at the University of Zaragoza in Spain, a synthesis of suitable cyclic allyl nitrones was carried out. In general aza-Cope rearrangements have attracted great interest because of the ubiquitous presence of nitrogen-containing structures in natural and biological products as well as synthetic intermediates. These compounds give rise to 2-aza-Cope rearrangement and we reported a full experimental study based on NMR kinetic experiments of the activation energies required for both neutral and catalyzed 2-aza- Cope rearrangements of nitrones
Development and optimization by experimental design of solid phase microextraction gas chromatography triple quadrupole mass spectrometry methods in aqueous matrices
(2012-11-30) Monteleone, Marcello; Tagarelli, Antonio; Gabriele, Bartolo; Bartolino, Roberto
Il presente lavoro di tesi relativo all‘attività di ricerca svolta durante il triennio di dottorato ha riguardato la messa a punto di metodi analitici per la determinazione di analiti in due distinte aree di interesse. La prima di ambito clinico ed ha riguardato la quantificazione in urina di metaboliti riconosciuti come marker in diagnostica clinica. In particolare ci si occupati della sarcosina come biomarker del tumore alla prostata, e di tre acidi: acido omovanillico (HVA), acido vanilmandelico (VMA) ed acido 5-idrossindoloacetico (5-HIAA) come marker urinari del neuroblastoma. Il secondo ambito di lavoro ha riguardato la quantificazione di inquinanti in matrici acquose, vale a dire carbammati ed acidi perfluoroalchilici. In particolare gli analiti, previa derivatizzazione con alchilcloroformiati (eccetto i carbammati), sono stati estratti dalle matrici acquose (acqua e urina) tramite la tecnica della microestrazione in fase solida (SPME) e successivamente analizzati mediante un gascromatografo con analizzatore di massa a triplo quadrupolo (GC-QqQ-MS). Le variabili significative della microestrazione in fase solida in ciascun metodo sono state ottimizzate tramite l‘approccio multivariato dell‘ ― Experimental Design‖. L‘utilizzo della tecnica SPME ha consentito di poter estrarre gli analiti direttamente dal campione da analizzare minimizzando i tempi di preparazione dello stesso e riducendo l‘uso di solventi organici, ottenendo metodi poco costosi e basso impatto ambientale. L‘utilizzo dello spettrometro di massa triplo quadrupolo, ha consentito di raggiungere livelli di sensibilità molto elevati e, nel contempo, di identificare gli analiti con maggiore sicurezza. In tutti i metodi sviluppati, sono stati ottenuti ottimi risultati in termini di linearità accuratezza e precisione. Anche i valori dei limiti di rilevabilità (LOD) e dei limiti di quantificazione (LOQ) ottenuti in ciascun metodo possono essere considerati soddisfacenti.
Development of cycloisomerization reactions for the synthesis of nitrogen or oxygen containing heterocycles
(2011-10-26) Spina, Rosella; Bartolino, Roberto; Gabriele, Bartolo; Salerno, Giuseppe; Colacino, Evelina
Different medicinal chemistry approaches towards the identification of novel targets in breast cancer
(2013-12-02) Pisano, Assunta; Bartolino, Roberto; Gabriele, Bartolo; Sindona, Giovanni; Maggiolini, Marcello
G protein-coupled receptors (GPCRs) belong to the largest family of cellsurface molecules representing the targets of approximately 40% of current medicinal drugs (Overington, J.P et al 2006). GPCRs are ubiquitous in mammalian (Bockaert, J. et al. 1999), regulate several physiological processes and play an important role in multiple diseases ranging from cardiovascular dysfunction, depression, pain, obesity to cancer (Rosenbaum D.M. et al. 2011). One member of this superfamily, named GPR30/GPER, mediates estrogen signaling in different cell contexts, leading to gene expression changes and relevant biological responses (Filardo E.J et al. 2000, Bologa C.G.et al. 2006, Maggiolini M. and Picard D. 2010). GPER acts by transactivating the Epidermal Growth Factor Receptor (EGFR), which thereafter induces the increase of intracellular cyclic AMP (cAMP), calcium mobilization and the activation of the phosphatidylinositol 3-kinase (PI3K) and the mitogen-activated protein kinases (MAPKs) (Maggiolini M. and Picard D. 2010). Moreover, the GPER-mediated transduction pathways activated by estrogens trigger the expression of a typical gene signature, including the expression of cfos and the gene encoding the connective tissue growth factor (CTGF), which are involved in the proliferation and migration of diverse cell types (Lappano R. et al 2012a, Madeo A. and Maggiolini M. 2010). On the basis of these findings, the first objective of the present study was the characterization of GPER from different points of view: GPERmediated signaling pathways and biological functions, selective ligands and molecular characterization of the receptors. In particular, the research project focused on:1. the transduction pathways by which the environmental contaminant Bisphenol A (BPA) influences cell proliferation and migration of human breast cancer cells and cancer-associated fibroblasts (CAFs); 2. the characterization of novel carbazole derivatives as GPER agonists in ER-negative breast cancer cells; 3. the isolation and characterization of GPER in estrogen-sensitive cancer cells by Mass Spectrometry. Additionally, the second section of this doctoral thesis was focused on the evaluation of the cytotoxic activity of novel synthesized compounds, given the interest and the need to discover new molecules against cancer. In particular, novel titanocene-complexes were studied evaluating their ability to elicit repressive effects on the growth of estrogen-sensitive breast cancer cells.
Experimental investigation of system performance for combined desalination processes with membrane capacitive deionisation (MCDI)
(Università della Calabria, 2021-10-31) Cañas Kurz, Edgardo E.; Critelli, Salvatore; Gabriele, Bartolo; Figoli, Alberto; Hoinkis, Jan
The water supply in many coastal regions worldwide is affected by progressive salinization. Here, the use of desalination technologies is a viable solution for obtaining freshwater. In this thesis, two modular concepts for brackish water (BW) desalination by the use of membrane capacitive deionization (MCDI) and low-pressure reverse osmosis (LPRO) were developed and tested at laboratory and pilot-scales with two pilot plants installed in Vietnam. The two concepts were developed by using computer-based calculations (software: WAVE) and evaluated in a socioeconomic and environmental multi-criteria analysis. The first plant consisting of subsurface arsenic removal (SAR) as pre-treatment and MCDI for desalination was installed in Tra Vinh, in the Mekong Delta for the treatment of arseniccontaminated groundwater with a concentration of total dissolved solids (TDS) of 1.65 g/L. Results showed the feasibility of the modular concept for producing drinking water (TDS<0.45 g/L) with a specific energy consumption (SEC) of <3 kWh/m³. The relationship between feed salinity and specific ion removal of the MCDI was evaluated in real environment and compared with laboratory experiments. The use of renewable energies such as solar and wind for autonomous supply was proven feasible for these technologies. The second pilot plant was installed in a riverine estuary in the region of Cần Giờ, where no access to freshwater is available due to the progressive salinization of river water and groundwater. Here, river water showed TDS concentrations of up to 25 g/L. The combined system consisted of UF pre-treatment, LPRO and MCDI to produce drinking water and product water with TDS of <0.45 g/L and <1.5 g/L, respectively with a total SEC of 5.8 kWh/m³. Additionally, the performance of the LPRO was compared to seawater-RO (SWRO) in pilot trials, which showed a SEC of 5.5 kWh/m³. Although the SEC of single-stage SWRO was lower, the separate production of drinking and product water by LPRO+MCDI showed different advantages including a reduced SEC of 5.2 kWh/m³ for product water and additional 0.6 kWh/m³ for drinking water. Finally, an optimization of the LPRO+MCDI can be possible by increasing the desalination efficiency of the MCDI, increasing the efficiency of LPRO-pump and the MCDI power supply, and by aiming at feed water qualities with lower salinity.
Food control quality by isotope dilution liquid chromatography-tandem mass spectrometry
(2014-06-13) Benabdelkamel, Hicham; Tagarelli, Antonio; Gabriele, Bartolo
The late part of the 20th century the advancement of knowledge regarding nutrition and disease prevention provided an opportunity for individuals to affect their own health. This expanding body of information helped people to understand how the environment and their own behaviour affected their body. People now had powerful tools to help maintaining and protecting their health. The understanding of how our diet affects our well being has dramatically changed the lifestyles and attitudes of people, who began to make menu and purchasing decisions based on how foods would affect their heath. A shift toward healthier lifestyles and healthier diets began. Food processors and marketers had to refocus their efforts from promoting foods for pleasure to promoting foods that fit in to a healthy diet. Primarily, the focus was on reducing fat and cholesterol in the diet and supplementing vitamins and minerals. Research began to demonstrate the presence of various phytochemicals in wine and juice make it from fruits and vegetables( such as stilbenes, falvoniods, polyphenols…) and specially in olive oil as ( polyphenol in dialdehyed form: oleochanthal, hydroxyoleocanthal..) These compounds have come to be known as nutraceuticals. The list of nutraceuticals present in wine, fruit drink and olive oil that are believed to have positive biological properties has been expanding. Food processors and developers have become very interested in exploiting these nutraceuticals for the production of foods that are not only part of a healthy diet but also improve the consumer’s health in another specific way. These foods have become known as “functional foods” means quality marker. The aim of this thesis has been to develop a analytical methods to determine the concentration of a group of these nutraceuticals in food , such as, quantitative determination of resveratrol in wine, pterostilbene in blueberry juice and dialdehyde form in olive oil using a sensitive high-performance liquid chromatographic separation method coupling with tandem-mass and isotope dilution to order to optimal the conditions for the analysis method, such as extraction procedure, matrices, column, quality controls, wavelength, mobile phases, run time, optimal separation (gradient, retention times), temperature, capillary voltage, cone voltages, vacuum and labelled internal standards, resulting in the best sensitivity and selectivity,The goodness and satisfactory of the method was performed according to, containing linear measuring range, quantification, lower limit of quantification (LLOQ), lower limit of detection (LLOD), quality controls, precision(RSD %), accuracy, recovery, stability and matrix effects. In conclusion, the described high-performance liquid chromatographic separation method with tandem-mass spectrometry detection and isotope dilution showed a satisfactory overall analytical performance well suited for applications in food quality control.
Innovative composite membranes for advanced applications
(2019-05-10) Grasso, Giuseppe; Critelli, Salvatore; Gabriele, Bartolo
Presented thesis work is mainly focused on coatings preparation, their potentiality and applications in membrane science: from water desalination to antibiofouling membranes, to gas separation. In fact, coating preparation represents an useful and versatile technique which allows a fine control of membrane properties and performance such as chemical or physical resistance, durability, etc. One of major drawbacks is represented by production costs, which can become important in scale-up operations. Therefore, although several type and methodologies for coating preparation are known and reported in literature, a lack of cheap, efficient and scale-up adaptable coating methods made their different preparation methods of particular interest. The results presented herein, concern the preparation of three different coating methods whose applications are briefly summarized below:  Chapter 2: Development of PVDF-f-Graphene Thin Film Composite Membrane for Membrane Distillation Chapter 2 reports a novel method for TFC membrane fabrication, using graphene layer coated on chemically-functionalized PVDF. PVDF is hydrophobic polymer whose properties are well suited for those applications in which hydrophobicity is needed such as Membrane Distillation. In order to increase adhesion between PVDF and graphene, we co-polymerized PVDF with a suitable monomer bearing aromatic part, using a procedure which involves 2 steps reaction: introduction of double bonds on polymer backbone by basic treatment followed by its reaction with monomer through radical reaction. Membranes have been prepared using functionalized PVDF polymer (PVDF-f) and tested on Direct Contact Membrane Distillation (DCMD) apparatus at first. Subsequently tests were conducted using PVDF-f-Graphene composite membrane, using graphene synthetized using Chemical Vapor Deposition ( CVD) method. Created membranes were analyzed and their chemical, physical and morphological properties were investigated. Membranes made using PVDF-f polymer exhibited good flux and salt rejection (up to 99.9 %), whereas graphene association to PVDF-f membranes leads to lower water flux but higher rejection and durability (up to 99.99 %). In chapter 3 a simple and innovative synthetic strategy for Acryloyloxyalkiltriethyl ammonium salts surfactants (AATEABs) starting from cheap and easily available chemicals is discussed. Herein reported surfactants can be used as coating for membranes to whom they confer high anti biofouling properties. Synthetic procedure was first optimized in order to work avoiding prohibitive conditions such as Inert atmosphere or high temperature and then applied to the synthesis of surfactants bearing a different alkyl-chain length. Antibacterial activity evaluation, has been done performing several tests against Gram +\- and yeast strains; results confirmed that AATEABs bearing C11 (AUTEAB) and C12 (ADTEAB) alkyl chain possess highest activity which is remarkable high for ADTEAB. AATEABs may find applications as polymerizable coatings for watr-treatment membranes ( commercial or not) to be used in Pressure-Driven Membrane Processes or in any other membrane-based system in which antifouling properties may play an important role.  Chapter 4: Thin Film Composite Membrane fabrication for gas separation: Defect control and bench-scale demonstration Fourth chapter of this thesis work, concerns the preparation of TFC membranes to be used for CO2/N2 separation, on the relationship between TFC membrane material and membrane properties and the role of the protective layer in determining the amount of defects, which is a crucial aspect for all the gas separation-related processes. We report a simple and efficient procedure which can also be applied to for defect controlling during scale-up process and which is not valid for CO2 separation membranes only. Results demonstrate a correlation between the properties of protective layer and separation performances: in particular, the possibility to apply a coating film on commercial membrane permits the creation of membranes in which the amount of defect is dramatically reduced. Another crucial aspect discussed in chapter 4 concerns the thickness of protective layer used for defect control: in fact, whereas the presence of protective layer plays an important role defect-free membrane creation process, its thickness impacts on separation operation. With our method, the preparation of membranes with very thin protective layer ( 0.1 μm or below) is possible.
Innovative fluorinated membranes for water and organic solvent treatment application
(2017-09-19) Ursino, Claudia; Carbone, Vincenzo; Gabriele, Bartolo; Figoli, Alberto
The aim of this thesis was to study the use of different types of fluoropolymer in order to prepare membranes for chemical and pharmaceutical applications. In fact, the potential use of fluoropolymeric membranes respect to other materials, at industrial levels, has several advantages such as high mechanical strength, high efficiency and stability. However, the unique properties of these materials such as excellent chemical and thermal strength make them extremely versatile but at the same time very difficult to process. As example, Ethylene-Chlorotrifluoroethylene (ECTFE) is insoluble in common organic solvents, and it can only be processed at high temperature, depending on the solvent used. In this work, three types of fluoropolymers have been studied, such as low-melting ECTFE (Halar®LMP-ECTFE), poly(vinylidene fluoride) (PVDF grade 1015) and perfluoropolyether (PFPEs) (Fluorolink®AD1700 and Fluorolink®MD700). Moreover, low-toxic solvents for humans and the environment have been appropriately selected and used for first time for solubilising the fluoropolymers of interest. -The Halar®LMP-ECTFE polymer was studied and characterized in terms of solubility parameters, compared with the standard Halar® ECTFE 901 polymer. In fact, this new grade of Halar® shows comparable properties with standard Halar® (hydrophobicity and mechanical properties), but lower crystallinity and lower melting point. Porous membranes and dense film were produced by thermally induced phase separation (TIPs). Two solvents, Diethyl Adipate (DEA) and Dibutyl Itaconate (DBI), never tested before, were selected. The chemical stability of the dense film was evaluated over time (192h) by swelling tests with aggressive organic solvents. Porous Halar®LMP-ECTFE membranes have been tested for organic solvents ultra- (UF) and nano-filtration (NF), such as methanol, ethanol and dimethylformamide. The results show that Halar®LMP ECTFE membranes are promising candidates to be used in separation processes under harsh conditions, such as chemicals production, purification and processing of food, nutraceuticals products and solvents recycling. - The influence of three different solvents in the membrane formation, using PVDF 1015 as polymer, was studied. Plasticizers from to Citroflex family, such as acetyl tributylcitrate (ATBC), acetyl triethylcitrate (ATEC) and triethylcitrate (TEC) have been selected and used. In particular ATEC and TEC as solvents, were used for the first time. Membranes were produced by thermally induced phase separation (TIPs) technique. The flat sheet membranes produced have been tested in microfiltration process (MF). These membranes can be used in several industrial applications such as sterilisation and clarification of pharmaceuticals or applied to separate contaminants from the water. - Perfluoropolyethers (PFPE) (Fluorolink®AD100 and Fluorolink®MD700) studied are new types of PFPE, UV cross-linkable. These PFPE photo-reticulated, have been used for coating commercial hydrophilic membrane, such as polyamide (PA) and polyethersulfone (PES) membranes. The aim of this work was to produce hydrophilic/hydrophobic coated membranes, keeping the morphology of the started membrane, unchanged. The study focused on morphological analysis, and on the influence of coating on the support membrane. The membranes produced, hydrophilic/hydrophobic, were characterized and the coating resistance was evaluated over time by direct contact with several chemical agents. The membranes were then tested, in membrane distillation process for direct contact (DCMD), using both deionized water and 0.6M saline. The results show that these coated membranes can be applied to desalination of seawater and wastewater treatment.
Innovative UV-LED polymerised bicontinuous microemulsion coating for membranes with special emphasis on MBRs
(2017-07-11) Schmidt, Slefan-André; Pantano, Pietro; Curcio, Efrem; Gabriele, Bartolo; Figoli, Alberto
The main objective of this work is the preparation of polymerisable bicontinuous microemulsion (PBM) coatings applied onto commercial membranes for improving the anti-fouling properties and performance, in terms of water flux and foulants rejection. Microstructured and nanostructured materials obtained by PBM have been widely investigated in the course of the last 30 years. The interest in microemulsion lies mainly in the possibility of dissolving larger amounts of oil and water by using polymerisable and non-polymerisable surfactants. By polymerising the bicontinuous microemulsion it is possible to produce transparent porous polymeric solids [Gan et al. (1995), Gan and Chew (1997)]. This thesis represents the follow-up of the work done by Galiano et al. (2015) and Deowan et al. (2016). Galiano et al. (2015) developed the PBM composition that based on a non-polymerisable surfactant (DTAB) and another polymerisable surfactant (AUTEAB). In their work the PBM was polymerised by redox initiators leading to a process that is very difficult to up-scale for a commercial application. Critical issues were, the polymerisation time (at least 20 minutes), and the reproducibility of the coating. Therefore, it is the aim of this work to develop another polymerisation technique that increases the polymerisation speed and allows the easy reproduction of membranes with defined properties. The polymerisation by photoinitiators excited by UV-light represents a promising possibility for this requirement as it has the potential of decreasing the polymerisation time down to a few seconds. Several photoinitiators were selected for their compatibility with the PBM, and studied for their conversion rate efficiency (section 5.1.5). As there is a wide range of potential UV-light sources available, several technologies are studied for their coating performance (section 5.1.3). Subsequent to that, experiments were done in order to define the ideal photoinitiator type and concentration while polymerising onto glass plates. The coating onto commercial membranes is studied deeply for e.g. different casting knife thickness or ambient temperature (section 5.2.2 As the polymerisation under inert conditions is expected to increase the polymerisation speed, experiments are done, both under inert and non-inert conditions. The final membrane, coated under the optimum conditions, is further characterised for their permeability under different conditions like transmembrane pressure (TMP), model foulant experiments and a fixed volume flow (section 5.2.3). Further characterisation is done by contact angle, SEM, AFM (section 5.2.5 to 5.2.7). The prepared PBM membranes are foreseen to be finally applied for model textile dye wastewater treatment by Membrane BioReactor (MBR) technology. According to the previous results of Deowan et al. (2016) higher permeate quality through increased COD, TOC, dyestuffs removal efficiency and stronger anti-fouling properties are expected. Consequently, lower operation/maintenance costs due to reduced necessary aeration for scouring purposes and reduced membrane cleaning cycles as well as less membrane replacement are of special interest for commercial applications. In the previous work of Deowan et al. (2016) a lab scaled MBR with a single membrane housing was used. As of the biocenosis of the bacteria inside the reactor tank, a comparison of the membrane performance of the PBM and commercial membrane is difficult to achieve. Therefore an existing MBR system was redesigned to allow the simultaneous run of a commercial and a PBM coated membrane (section 4.1). As the revamp requires also additional sensors, the data acquisition needs to be adapted as well. To assure the proper function of the MBR the system was running for long term with two commercial membranes using a model textile wastewater (see 5.3.2). Finally the PBM coated membrane was compared with a commercial one for their performance in the MBR. Initial experiments for the water permeability are done as preparation for future work (see 5.3.3).
Integrated membrane operations for the recovery of bioactive compounds from juice and by-products of the Citrus fruits production
(2009-10-30) Liguori, Angelo; Cassano, Alfredo; Gabriele, Bartolo; Conidi, Carmela
Materiali polimerici funzionali per applicazioni farmaceutiche e biomedicali
(2011-10-26) Ferrarelli, Teresa; Bartolino, Roberto; Trombino, Sonia; Gabriele, Bartolo
Mechanics of cell wall remodelling in mycobacterium tuberculosis
(2012-10-29) Mavrici, Daniela; Gabriele, Bartolo; Sindona, G.; Alber, T.
Modern mass spectrometric applications in the structure and function evaluation of active principles
(2011-10-26) Malaj, Naim; Gabriele, Bartolo; Sindona, Giovanni; Bartolino, Roberto
Modified amino acids as useful tool for peptide synthesis and their measurement in complex matrices
(2012-11-28) Spinella, Mariagiovanna; Gabriele, Bartolo; Liguori, Angelo
Negli ultimi anni sono stati scoperti e caratterizzati numerosi peptidi biologicamente attivi che, mediante interazioni con opportuni recettori, influenzano le cellule in una serie di funzioni vitali quali il metabolismo, le difese immunitarie, la proliferazione cellulare. Questi peptidi, tuttavia, nella loro forma nativa non possono essere utilizzati come farmaci, data la loro scarsa stabilità metabolica e il difficile assorbimento dopo somministrazione orale; bisogna perciò disporre di pepdidomimetici, che siano in grado di mimare gli effetti farmacologici dei peptidi naturali, ma che presentino allo stesso tempo una maggiore stabilità e biodisponibilità. Nella realizzazione della sintesi peptidica riveste un ruolo importante la scelta di gruppi protettori utili a mascherare la funzione amminica e carbossilica di amminoacidi e peptidi. La necessità di una sequenziale protezione e deprotezione delle varie funzionalità presenti fa si che, sia l’introduzione, che la rimozione di un gruppo protettore richiedano un’accurata progettazione sintetica, al fine di garantire il grado richiesto di ortogonalità tra i vari gruppi protettori utilizzati. Nella maggior parte dei casi per proteggere la funzione carbossilica di α-amminoacidi si utilizzano gruppi protettori semipermanenti che rimangono inalterati durante la costruzione della catena peptidica e vengono rimossi alla fine della sintesi. La formazione di esteri è stata allo scopo ampiamente utilizzata. In particolare il gruppo carbossilico viene convertito in estere metilico, benzilico, tert-butilico e benzidrilico. Tuttavia, il ripristino della funzione carbossilica al termine della sintesi peptidica presenta delle difficoltà. Infatti, in questi casi la deprotezione della funzione carbossilica prevede l’idrolisi basica degli stessi esteri in presenza di solventi organici. Questa procedura, anche quando è eseguita in condizioni strettamente controllate, può causare epimerizzazione del peptide e altre reazioni collaterali. Allo scopo è stata realizzata la deprotezione della funzione carbossilica di esteri metilici di alfa-amminoacidi utilizzando ilidi allo zolfo in particolare la dimetilsulfossonio metilide. In un tipico esperimento l'estere metilico della N-nosil-L-alanina è stato trattato con la metilide di dimetilsolfossonio in THF nel rapporto molare 1:2 per trenta minuti. A seguito di idrolisi acida si recupera con resa quantitativa il corrispondente amminoacido deprotetto sulla funzione carbossilica. La reazione è stata applicata ad una serie di esteri metilici di alfa-amminoacidi protetti sulla funzione amminica con il gruppo terbutossicarbonile (Boc), nosile (Ns)e benzilossicarbonile (Cbz) e di esteri metilici di acidi carbossilici. In tutti gli esperimenti eseguiti il corrispondente acido carbossilico è stato recuperato con rese elevate e in forma pura. La deprotezione della funzione carbossilica è stata realizzata con successo anche con substrati amminoacidici protetti in catena laterale con gruppi protettori acido-labili. Inoltre, eseguendo la procedura su substrati enantiopuri, è stato dimostrato che la reazione avviene senza racemizzazione. Questa metodologia è generale e può essere considerata una valida alternativa all'idrolisi degli esteri quando un substrato è sensibile alle condizioni di idrolisi. La dimetilsulfossonio metilide è stata usata, anche, come unico ed utile reagente per la deprotezione simultanea della funzione carbossilica protetta come estere e della funzione amminica protetta con il 9-fluorenilmetossicarbonile (Fmoc) di α-amino acidi e oligopeptidi. La nuova metodologia è stata applicata con successo nella sintesi peptidica, basata sulla “Fmoc-chemistry”, sia in fase solida che in soluzione. I corrispondenti amminoacidi e peptidi liberi sulla funzione carbossilica e sulla funzione amminica vengono recuperati in tempi brevi ed in ottime rese. La nuova procedura è stata applicata con ottimi risultati, anche, su peptidi contenenti amino acidi protetti in catena laterale con gruppi protettori acido-labili. Inoltre, è stato studiato l’andamento stereochimico della reazione di deprotezione mediante risonanza magnetica nucleare (1H-NMR). I dati 1H-NMR di miscele di prodotti diastereoisomerici tra di loro indicano chiaramente che le condizioni adottate non causano epimerizzazione degli stereocentri presenti nei substrati di partenza. Nel mio lavoro di ricerca mi sono occupata, inoltre, dello sviluppo di nuove metodologie per la sintesi di amminoacidi N-alchilati, utili building blocks per la sintesi di peptidi biologicamente attivi. In questo campo è stata messa a punto un' efficiente metodologia "one-pot" per l’ N-alchilazione di una serie di N-arilsolfonil-α-amminoacidi metil esteri recanti sostituenti diversi in posizione 4 dell'anello aromatico solfonammidico. In particolare, si è confrontata la reattività di queste specie con diazometano e trimetilossonio tetrafluoroborato in processi di N-metilazione e con trietilossonio tetrafluoroborato in processi di N-etilazione. La metilazione con diazometano ha avuto esito negativo per i derivati N-arilsolfon-ammidici contenenti gruppi elettron-donatori sull'anello aromatico. In questi casi il trimetilossonio tetrafluoroborato si è mostrato il reagente di scelta per la N-metilazione diretta e quantitativa. Il trietilossonio tetrafluoroborato ha dimostrato essere un reagente molto efficace per la preparazione di N-etil derivati di tutti gli N-arilsolfonil-α-ammino acidi metil esteri testati. Nell’ultima parte del mio lavoro di ricerca mi sono occupata del riconoscimento e della misura di analiti contenuti in matrici di interesse alimentare. Nella carne il contenuto di amminoacidi liberi ed il contenuto di acidi grassi liberi sono due parametri importanti utilizzati per determinare la sua qualità. Questi composti hanno un ruolo molto importante nella definizione delle caratteristiche sensoriali dei prodotti a base di carne. E' stata sviluppata, a tale proposito, una procedura innovativa per la misurazione del contenuto di amminoacidi e acidi grassi liberi nella carne e nei prodotti a base di carne. La procedura messa a punto prevede un singolo esperimento per la determinazione simultanea del profilo degli acidi grassi e degli amminoacidi. Gli analiti di interesse sono rapidamente estratti dalla matrice carnea e derivatizzati usando il metil cloroformiato. Questo reagente consente la trasformazione dei due gruppi di analiti nei corrispondenti N-metilossicarbonil aminoacidi metil esteri ed esteri metilici degli acidi grassi, che possono essere facilmente estratti per la loro successiva identificazione e quantificazione. La misurazione dei derivati degli acidi grassi e degli amminoacidi ottenuti viene eseguita mediante GC/MS. Il principale vantaggio del protocollo messo a punto è la determinazione simultanea di due importanti classi di analiti che sono di grande importanza nell'analisi e caratterizzazione degli alimenti. In un altro lavoro sono poi stati messi a confronto alcuni parametri importanti quali il contenuto di amminoacidi liberi e ammine biogeniche di prodotti a base di carne stagionati industriali e fatti in casa. A questo scopo, la "soppressata" e la salsiccia", due tipici salumi stagionati prodotti nel Sud Italia, sono stati analizzati. Le salsicce fatte in casa hanno mostrato un livello più alto di ammine biogeniche libere rispetto al contenuto dei prodotti industriali, molto probabilmente perché la formazione di ammine biogeniche nei prodotti industriali è limitata dall'uso di colture starter. Le salsicce industriali sono caratterizzate, invece, da un più alto contenuto di amminoacidi liberi totali.
Multivariate curve resolution methodologies in photostability drug studies
(2014-11-27) De Luca, Michele; Bartolino, Roberto; Gabriele, Bartolo; Ragno, Gaetano
New challenges in the determination of food contaminants
(2009-10-30) Attya, Mohamed; Gabriele, Bartolo; Di Donna, Leonardo
New palladium catalyzed carbonylation processes for the synthesis of molecules of applicative interest
(2016-02-26) Ziccarelli, Ida; Mancuso, Raffaella; Gabriele, Bartolo
In the present investigation we have developed new palladium-catalyzed carbonylation processes for the synthesis of molecules of applicative interest. In particular, isoindolinone and isobenzofuranimine derivatives have been synthetized starting from 2-alkynylbenzamides by a divergent PdI2-catalyzed multicomponent carbonylative approach, depending on the nature of the external nucleophile and reaction conditions. Thus, oxidative carbonylation of 2- ethynylbenzamides, bearing a terminal triple bond, carried out in the presence of a secondary amine as external nucleophile, selectively led to the formation of 3- [(dialkylcarbamoyl)methylene]isoindolin-1-ones. On the other hand, 3-[(alkoxycarbonyl)methylene]-isobenzofuran-1(3H)imines were selectively obtained when the oxidative carbonylation of 2-alkynylbenzamides, bearing a terminal or an internal triple bond, was carried out in the presence of an alcohol R'OH (such as methanol or ethanol) as the external nucleophile and HC(OR')3 as a dehydrating agent, necessary to avoid substrate hydrolysis. Isoindolinone derivatives were used as starting material to obtain the corresponding spiro-isoindolin isoxazolidines, able to work as inhibitors of the p53-MDM2 interaction: biological test showed that these compounds have antiproliferative activity on cancer cell lines of neuroblastoma, colorectal adenocarcinoma and hepatocarcinoma in the μM range. Isobenzofuranimine derivatives, instead, showed a strong phytotoxic effect on shoot and root systems of Arabidopsis thaliana, a weed which compete with crops for edaphic resources such as water and nutrients. Furo-furanone derivatives have been synthetized by PdI2-catalyzed oxidative carbonylation starting from 4-yn-1,3-diols, substrates bearing themselves nucleophilic groups in a suitable position to give a “double” intramolecular nucleophilic attack so as to obtain functionalized bicyclic molecules. Biological assay showed that these compounds are promising anticancer agents. Finally, part of this PhD was spent at Leibniz Institute for Catalysis in Rostock University in order to develop a new heterogeneous catalyst based on palladium via immobilization and pyrolysis on activated carbon. Palladium supported on N-doped carbon was applied to the alkoxycarbonylation of aryl iodides to benzoates, important feedstocks and key intermediates for pharmaceuticals.