0000000000260958
AUTHOR
Alberto Sutera
showing 15 related works from this author
The effects of structural changes on the anti-microbial and anti-proliferative activities of diimidazolium salts
2017
An array of diimidazolium salts has been synthesized and used to investigate their anti-microbial and anti-proliferative activities. In particular, salts based on the 3,30-di-n-alkyl-1,10-(1,n-phenylenedimethylene)- diimidazolium cation and differing in the alkyl chain length on the imidazolium ion, the isomeric substitution on the aromatic spacer and in the anion nature were used. The anti-proliferative activity was evaluated against cervical (HeLa), colon adenocarcinoma (HT-29) and breast (SKBR3) cancer cell lines. In the latter case, also a morphological assessment after treatment with salts was performed. All salts were tested for their hemolytic activity against human erythrocytes. On …
Supramolecular Hydro- and Ionogels: A Study of Their Properties and Antibacterial Activity.
2017
Diimidazolium-based organic salts, bearing peptides or amino acids as anions have been synthesised and tested for their gelling ability in biocompatible solvents. These low molecular weight salts were successfully used as gelators in phosphate buffered saline (PBS) solution and ionic liquids. Then, the properties of the obtained soft materials were analysed in terms of melting temperature and gel strength as accounted for by rheological investigations. The gel-phase formation was studied by using UV/Vis and resonance light scattering measurements, whereas the morphology of the soft materials was analysed by using polarised optical microscopy and scanning electron microscopy. To get informat…
Synthesis, characterization and antimicrobial activity of polyaminocyclodextrin-capped Ag Nanoparticles
2015
Biocompatible Ag nanocomposites were prepared by photoreduction of ammoniacal silver acetate in the presence of a polyaminocyclodextrin, namely the poly-{6-[3-(2-(3-aminopropylamino)-ethylamino)-propylamino]}-(6-deoxy)-b-CD (amCD, figure 1). The obtained Ag-amCD systems, which possess an oniontype structure [1] with a metal core surrounded by several layers of the capping agent, were characterized by means of various complementary techniques. In particular, FT-IR spectroscopy confirmed the presence of the amCD scaffold in the composite, and evidenced a partial oxidative degradation of the polyamine branches,due to the fact that these groups function as sacrificial reducing agents in the pho…
Chemo-enzymatic Conversion of Glucose in 5-Hydroxymethylfurfural: The Joint Effect of Ionic Liquids and Ultrasound
2020
For the valorization of lignocellulosic biomass, a key step is unlocking the conversion of glucose to suitable chemical platforms. To this aim, we herein describe the sequential chemo-enzymatic conversion of glucose into 5-hydroxymethylfurfural (5-HMF), in two steps: glucose isomerization to fructose, catalyzed by glucose isomerase (GI) and fructose dehydration to 5-HMF promoted by Amberlyst 15. The novelty of our approach lies in the use of crude cell extracts of Streptomyces coelicolor showing GI activity, as isomerization catalysts, along with a commercial immobilized GI. Under optimized reaction conditions, we obtained a conversion to 5-HMF (C5‑HMF) from glucose of 50% in the H2O/[bmim]…
STRATEGIE PER IL MIGLIORAMENTO DELLA PRODUZIONE E LO SVILUPPO DI MOLECOLE AD ATTIVITÀ ANTIBIOTICA DI ORIGINE NATURALE O DI SINTESI CHIMICA
The emergence of multi-drug resistant (MDR) bacterial strains is an urgent problem derived from the widespread and uncontrolled use of antibiotics. Therefore, new arrays of lead compounds exerting antimicrobial activity are necessary to contrast the spreading of MDR pathogens. Between 1980 and 2003, the interest in scientific research programs aimed to the new drug discovery by large pharmaceutical companies progressively decreased due to increasing costs in the respect of i) the low discovery rate of new leads, ii) the small amounts of product recovery needing process optimization and, finally, iii) regulatory obstacles associated with long-lasting pre-clinical and clinical trials for ther…
Diimidazolium organic salts and supramolecular gels exerting antimicrobial activity
Actinorhodin production intensification by nanofibrous membranes in Streptomyces coelicolor cultures
2016
In this work, electrospun polycaprolactone (PCL) and polylactic acid (PLA) membranes, subjected or not to O2-plasma treatment, werwe used as support for cell-immobilization in S. coelicolor immobilized-cells created a compact biofilm on both kinds of membranes.
Photosynthesized silver-polyaminocyclodextrin nanocomposites as promising antibacterial agents with improved activity
2016
Ag nanocomposites were prepared by photoreduction of ammoniacal silver acetate in the presence of poly-{6-[3-(2-(3-aminopropylamino)ethylamino)propylamino]}-(6-deoxy)-β-CD (amCD). The obtained systems were characterized by means of various complementary techniques (UV-vis, FT-IR, TEM, SAED). In particular, FT-IR spectroscopy evidenced a partial oxidative degradation of the polyamine branches of the capping auxiliary, due to the fact that these groups function as a sacrificial reducing agent in the photoinduced formation of the Ag metal core. TEM and SAED micrographs showed that the Ag cores possess a relatively low polydispersity and a significantly crystalline character. The Ag–amCD system…
TrpM, a Small Protein Modulating Tryptophan Biosynthesis and Morpho-Physiological Differentiation in Streptomyces coelicolor A3(2).
2016
In the model actinomycete Streptomyces coelicolor A3(2), small open reading frames encoding proteins with unknown functions were identified in several amino acid biosynthetic gene operons, such as SCO2038 (trpX) in the tryptophan trpCXBA locus. In this study, the role of the corresponding protein in tryptophan biosynthesis was investigated by combining phenotypic and molecular analyses. The 2038KO mutant strain was characterized by delayed growth, smaller aerial hyphae and reduced production of spores and actinorhodin antibiotic, with respect to the WT strain. The capability of this mutant to grow on minimal medium was rescued by tryptophan and tryptophan precursor (serine and/or indole) su…
DICATIONIC IMIDAZOLIUM SALTS: TUNABLE ANTIMICROBIAL AND ANTITUMORAL CHEMIOTHERAPEUTIC LEADS
2015
The chemical synthesis of novel chemotherapeutical leads is evolving thanks to possibility to design molecules with desired physical-chemical and, thus, biological properties. The imidazolium salts, recently proven effective to inhibit bacterial and/or cancer cell growth, posses an amphiphilic nature that is conferred by the imidazolium cation having a polar head generally coupled with aliphatic side chains. Thus, biological properties of imidazolium salts can be tuned through modifications involving the cation structure and/or the anion nature. By covalently linking two imidazolium rings, di-imidazolium salts were obtainedobtain differing in: i) kind of anions; ii) geometric isomerization …
Effect of PCL/PEG-Based Membranes on Actinorhodin Production in Streptomyces coelicolor Cultivations
2015
The actinomycetes, Gram-positive filamentous bacteria, are the most prolific source of natural occurring antibiotics. At an industrial level, antibiotics from actinomycete strains are produced by means of submerged fermentations, where one of the major factors negatively affecting bioproductivity is the pellet-shaped biomass growth. The immobilization of microorganisms on properly chosen supports prevents cell-cell aggregation resulting in improving the biosynthetic capability. Thus, novel porous biopolymer-based devices are developed by combining melt mixing and particulate leaching. In particular, polycaprolactone (PCL), polyethylene glycol (PEG), and sodium chloride (NaCl) with different…
Plasma modified PLA electrospun membranes for actinorhodin production intensification in Streptomyces coelicolor immobilized-cell cultivations
2017
Most of industrially relevant bioproducts are produced by submerged cultivations of actinomycetes. The immobilization of these Gram-positive filamentous bacteria on suitable porous supports may prevent mycelial cell-cell aggregation and pellet formation which usually negatively affect actinomycete submerged cultivations, thus, resulting in an improved biosynthetic capability. In this work, electrospun polylactic acid (PLA) membranes, subjected or not to O2-plasma treatment (PLA-plasma), were used as support for immobilized-cell submerged cultivations of Streptomyces coelicolor M145. This strain produces different bioactive compounds, including the blue-pigmented actinorhodin (ACT) and red-p…
Stategie metaboliche indotte dal triptofano in Streptomyces coelicolor
2013
Pirin: A novel redox-sensitive modulator of primary and secondary metabolism in Streptomyces
2018
Pirins are evolutionarily conserved iron-containing proteins that are found in all kingdoms of life, and have been implicated in diverse molecular processes, mostly associated with cellular stress. In the present study, we started from the evidence that the insertional inactivation of pirin-like gene SAM23877_RS18305 (pirA) by Phi C31 Att/Int system-based vectors in spiramycin-producing strain Streptomyces ambofaciens ATCC 23877 resulted in marked effects on central carbon and energy metabolism gene expression, high sensitivity to oxidative injury and repression of polyketide antibiotic production. By using integrated transcriptomic, proteomic and metabolite profiling, together with genetic…