17 research outputs found
Progettazione e caratterizzazione di nuovi composti antimicrobici per applicazioni nel settore alimentare
No full textAd oggi, l’industria alimentare sta affrontando sempre nuove sfide dovute all’insorgenza dei cosiddetti patogeni emergenti e allo sviluppo per molte specie microbiche di profili di resistenza nei confronti dei più comuni antibiotici, rappresentando una continua minaccia per la salute pubblica. Vi è quindi un crescente interesse verso soluzioni innovative che consentano di aumentare la conservabilità degli alimenti mantenendo alti gli standard di qualità e sicurezza. In questo scenario si inserisce il presente progetto di tesi riguardante la “Progettazione e caratterizzazione di nuovi composti antimicrobici per applicazioni nel settore alimentare”, svolto in collaborazione con il partner aziendale Materias s.r.l. Il progetto si propone di sviluppare un imballaggio “attivo” identificando e ottimizzando le condizioni in grado di coniugare in modo stabile, ad uno dei film plastici più largamente adoperati per il confezionamento alimentare, due peptidi antimicrobici progettati dal gruppo di ricerca della Dott.ssa Palmieri.
La progettazione delle due molecole antimicrobiche è avvenuta attraverso due diversi tipi di approcci sperimentali utilizzando sequenze note usate come template. La molecola denominata 1018-K6, oggetto di un brevetto depositato da Materias s.r.l. (No. 102017000080068, 2017), è stata sviluppata a partire da sequenze di diverse catelicidine bovine, peptidi coinvolti nella risposta immune innata e localizzati a livello dei granuli dei neutrofili polimorfonucleati, i quali, come le altre molecole appartenenti alla stessa categoria, sono ben noti per il loro ampio spettro d’azione. La molecola denominata MTP1, dove MTP sta per “Mitochondrial Targeted Peptides”, è stata disegnata usando come modello sequenze specifiche di proteine mitocondriali note. L’idea di utilizzare come riferimento tratti di proteine mitocondriali è stata suggerita da studi recenti che hanno dimostrato, per taluni peptidi antimicrobici, un effetto citotossico a carico di cellule tumorali, in quanto in grado di operare un danno selettivo a livello della membrana mitocondriale. Un’ulteriore evidenza che ha avvalorato la potenzialità di questa strategia di progettazione, si basa sulla presenza nelle membrane batteriche di almeno il 5% delle proteine che costituiscono la membrana mitocondriale. Da ciò è scaturita l’ipotesi che MTP1 potesse agire come peptide ad attività antimicrobica attraverso l'interazione e conseguente destabilizzazione della membrana plasmatica in batteri patogeni. Le due suddette sequenze, già oggetto da qualche anno di studi preliminari circa il loro potere antimicrobico, hanno mostrato una selettività verso bersagli microbici differenti. Da qui, l’idea di utilizzarle nel seguente progetto anche in combinazione, allo scopo di ottenere un’unica soluzione avente potenzialmente un più ampio spettro d’azione antimicrobica.
Lo studio ha previsto una prima fase di caratterizzazione strutturale delle molecole antimicrobiche sia singolarmente che in miscela, in diverse condizioni ambientali di pH, temperatura e salinità. La sperimentazione sviluppata in un intervallo temporale di 24 h, ha inoltre permesso di selezionare le soluzioni peptidiche risultate più stabili, ovvero in grado di preservare l’integrità strutturale, nelle diverse condizioni investigate. Successivamente, presso i locali del Dipartimento di Medicina Veterinaria e Produzioni Animali dell’Università Federico II di Napoli, in collaborazione con il gruppo di ricerca del Prof. Anastasio, le molecole selezionate sono state sottoposte ad analisi di attività antimicrobica nei confronti di quattro microrganismi sia patogeni che non, isolati da matrici alimentari quali: Staphylococcus aureus MRSA M7 isolato da carne di suino, Staphylococcus aureus SA 4 isolato da un prodotto lattiero-caseario (Svizzera), Listeria monocytogenes 92 isolato da carne bovina e lieviti. Parallelamente alla valutazione del loro potere antimicrobico, le stesse molecole sono state sottoposte ad analisi di citotossicità, per verificare la mancanza di effetti avversi nei confronti di cellule eucariotiche, tale da incoraggiarne l’uso a livello biotecnologico. Infine sono state messe a punto le condizioni di bioconiugazione dei bio-composti ai film di polipropilene ottenendo diverse soluzioni di polimeri funzionalizzati. Negli ultimi anni, il packaging antimicrobico si sta facendo sempre più largo nel settore degli imballaggi, in quanto il suo impiego presenta risvolti positivi sia a livello sociale che economico. Inoltre, è importante ricordare che la strada che conduce alla registrazione di un nuovo tipo di packaging alimentare non è priva di ostacoli, in quanto esiste una stringente normativa che regola sia a livello nazionale che europeo l’utilizzo dei film plastici nel settore della food industry. In tale contesto va tenuto conto che l'imballaggio alimentare non va inteso come una semplice barriera protettiva, ma esso rappresenta un vero e proprio componente "attivo", che dovrebbe preservare la qualità, la sicurezza e la shelf-life degli alimenti. Nel presente studio, il target alimentare dell’imballaggio progettato è stato scelto nell’ambito di tre diverse tipologie di prodotti maggiormente riconosciuti per la loro facile deperibilità quali quelli lattiero-caseari, carnei e ittici, per i quali il mantenimento dell’integrità per un tempo più lungo, anche di pochi giorni, si traduce spesso in un considerevole ritorno economico
An Active Peptide-Based Packaging System to Improve the Freshness and Safety of Fish Products: A Case Study
No full textFresh fish are highly perishable, owing mainly to their moisture content, high amount of free amino acids and polyunsaturated fatty acids. Microorganisms and chemical reactions cause the spoilage, leading to loss in quality, human health risks and a market value reduction. Therefore, the fishing industry has always been willing to explore new technologies to increase quality and safety of fish products through a decrease of the microbiological and biochemical damage. In this context, antimicrobial active packaging is one such promising solution to meet consumer demands. The main objective of this study was to evaluate the effects of an active polypropylene-based packaging functionalized with the antimicrobial peptide 1018K6 on microbial growth, physicochemical properties and the sensory attributes of raw salmon fillets. The results showed that application of 1018K6-polypropylene strongly inhibited the microbial growth of both pathogenic and specific spoilage organisms (SSOs) on fish fillets after 7 days. Moreover, salmon also kept its freshness as per volatile chemical spoilage indices (CSIs) during storage. Similar results were obtained on hamburgers of Sarda sarda performing the same analyses. This work provides further evidence that 1018K6-polymers have good potential as antimicrobial packaging for application in the food market to enhance quality and preserve the sensorial properties of fish products
In vitro assessment of antimicrobial activity exerted by antimicrobial peptides against BoNT-producing clostridia: preliminary results
No full textDisclose ATP-synthase as a protein target of the antimicrobial peptide RiLK1 in Escherichia coli: An alternative receptor-mediated bactericidal mechanism
No full textIn this study, we investigated the mechanism of action of the 10-aminoacid RiLK1 peptide against Escherichia coli
(strain ATCC 25922), both in vitro and in contaminated meat matrices. Therefore, a mass spectrometry-based
functional proteomics platform was employed to identify specific molecular targets of RiLK1 in a membrane
protein-enriched E. coli lysate and to obtain information on their interaction mechanism. This target deconvo-
lution approach combines MS-limited proteolysis techniques, like Drug Affinity Responsive Target Stability
(DARTS) and targeted-limited Proteolysis coupled with Mass Spectrometry (t-LiP-MS). The b and δ subunits of
the multimeric enzymatic complex ATP synthase, the smallest known biological nanomotor found in all cells,
were identified as the relevant RiLK1 membrane protein targets. Extensive molecular docking and biochemical
analyses validated and improved the suggested interaction profile. These unique findings could rationally explain
the relevant RiLK1 bactericidal effects against E. coli strains, suggesting its potential application in food safety
and preservatio
Functionalized Polymeric Materials with Bio-Derived Antimicrobial Peptides for "Active" Packaging
No full textFood packaging is not only a simple protective barrier, but a real “active” component, which is expected to preserve food quality, safety and shelf-life. Therefore, the materials used for packaging production should show peculiar features and properties. Specifically, antimicrobial packaging has recently gained great attention with respect to both social and economic impacts. In this paper, the results obtained by using a polymer material functionalized by a small synthetic peptide as “active” packaging are reported. The surface of Polyethylene Terephthalate (PET), one of the most commonly used plastic materials in food packaging, was plasma-activated and covalently bio-conjugated to a bactenecin-derivative peptide named 1018K6, previously characterized in terms of antimicrobial and antibiofilm activities. The immobilization of the peptide occurred at a high yield and no release was observed under different environmental conditions. Moreover, preliminary data clearly demonstrated that the “active” packaging was able to significantly reduce the total bacterial count together with yeast and mold spoilage in food-dairy products. Finally, the functionalized-PET polymer showed stronger efficiency in inhibiting biofilm growth, using a Listeria monocytogenes strain isolated from food products. The use of these “active” materials would greatly decrease the risk of pathogen development and increase the shelf-life in the food industry, showing a real potential against a panel of microorganisms upon exposure to fresh and stored products, high chemical stability and re-use possibility
La declinabilità didattica del group-based early start Denver model (G-ESDM) nella scuola dell'infanzia
No full text2016 - 2017Il disturbo dello spettro autistico è oggi il fenomeno più studiato nel mondo, la sua
complessità ed il mistero che da sempre lo ha avvolto hanno fatto si che nel tempo tutti i
domini di ricerca si interessassero alsuo studio ed approfondimento. Nonostante i progressi
scientifici e le sofisticate tecnologie sviluppate per lo studio del genoma umano e del
funzionamento cerebrale le cause restano ancora ignote. Sempre più si sostiene la tesi che
alla base del disturbo vi sia una multifattorialità eziologica difficile da comprendere ed
interpretare. Tutti i Paesi del mondo sono però concordi nell’affermare che un ruolo cruciale
per le persone con disturbo dello spettro autistico rivestono i modelli e i programmi di
intervento educativi precoci. Laddove non è possibile individuare ed intervenire sulle cause
del disturbo, sull’uomo grava la responsabilità di assicurare alle persone, ma in primis ai
bambini, con disturbo dello spettro autistico adeguate misure di intervento, sostegno e
sviluppo in un’ottica di orientamento permanente e di long-life learning.
La necessità avvertita all’interno del contesto nazionale è quella di individuare,
attraverso specifiche attività di ricerca, “buone pratiche educative” per gli studenti con
disturbo dello spettro autistico, al fine di poterle, poi, proporre ai docenti curricolari e di
sostegno per il miglioramento delle loro competenze operative. Sul territorio nazionale si
sono avviate interessanti ricerche volte a sperimentare la possibile applicazione di interventi
nati in ambito internazionale. In realtà molti degli interventi si collocano su un livello
clinico-terapeutico – si pensi all’ABA, al Discrete Trail Training, al Verbal Behavior
Teaching, al Developmental, Individual-differences, Relationship-based model – poiché i
corsi che vengono proposti puntano a formare terapisti in grado di lavorare in un rapporto
one-to-one con i bambini con autismo. Altri interventi, invece, sono stati approfonditi e
sperimentati all’interno del contesto educativo – si pensi all’Augumentative and Alternative
Communication, al Picture Exchange Communication System, al Video-modeling – e
forniscono ai docenti utili linee guida per poter lavorare con i bambini con disturbo dello
spettro autistico. Tra i modelli di intervento sviluppati a livello internazionale, e suggeriti dal
Ministero nei corsi di formazione per i docenti, emerge l’Early Start Denver Model, modello
di intervento globale, intensivo e precoce per bambini con disturbo dello spettro autistico
sviluppato da Sally J. Roger e Geraldine Dawson. Esso è considerato evidence-based
practice ed ingloba al suo interno modelli evolutivo-relazionali con tecniche e pratiche
dell’Applied Behavioral Analysys e del Pivotal Responsive Training.
A partire da tale modello nel 2017 è stato sviluppato, da Giacomo Vivanti, Ed
Duncan, Geraldine Dawson e Sally J. Rogers, il Group-Based Early Start Denver Model, modello di intervento implementabile nella scuola dell’infanzia e rivolto a bambini con
autismo. Proprio tu tale modello si concentra lo studio di fattibilità presentato all’interno
del presente lavoro.
Il lavoro di ricerca si configura come studio di fattibilità volto ad indagare, attraverso
l’analisi della letteratura scientifica di riferimento, l’accettabilità, l’implementazione,
adattamento ed integrazione del Group-Based Early Start Denver Model all’interno della
scuola dell’infanzia italiana.
Uno studio di fattibilità condotto a partire dall’analisi degli elementi presentati
rappresenta, in accordo con i principi dell’Index For Inclusion, il primo passo per lo
sviluppo di una possibile ricerca futura: prima ancora di progettare una sperimentazione in
ambito didattico è indispensabile riflettere sulle teorie che sono alla base del modello, sui
valori socio-culturali che il modello di intervento contiene, sui vincoli politici e legislativi
che ne potrebbero ostacolare la sperimentazione e la declinabilità. [a cura dell'Autore]The Autism Spectrum Disorder is today the most studied phenomenon in the world, its complexity and the mystery that has always enveloped it have meant that over time all the research domains were interested in its study. Despite the scientific advances and the sophisticated technologies developed for the study of the human genome and of brain functioning, the causes of the ASD remain unknown. However, all the Countries of the world are in agreement that a crucial role for people with autism spectrum disorder are the early educational models and early intervention programs. Where it is not possible to identify and intervene on the causes of the disturbance, the human responsibility bears the responsibility to ensure people, but primarily children, with autism spectrum disorder adequate measures of intervention, support and development in a perspective of permanent guidance and of long-life learning.
The need felt within the national context is to identify, through specific research activities, "good educational practices" for students with autism spectrum disorder, in order to be able then to propose to the curriculum teachers and support for the improvement of their operational skills. On the national territory, interesting research has begun to experiment the possible application of interventions born in the international field. In fact, many of the interventions are on a clinical-therapeutic level - ABA, Discrete Trail Training, Verbal Behavior Teaching, Developmental, Individual-differences, Relationship-based model - because the courses that are proposed aim at train therapists able to work in a one-on-one relationship with children with autism. Other interventions, on the other hand, have been deepened and experimented within the educational context - Augmentative and Alternative Communication, Picture Exchange Communication System, Video-modeling - and provide teachers with useful guidelines for working with children with autism spectrum disorder.
Among the intervention models developed at international level, and suggested by the Ministry in training courses for teachers, the Early Start Denver Model emerges, a model of global intervention, intensive and early for children with autism spectrum disorder developed by Sally J. Roger and Geraldine Dawson. It is considered evidence-based practice and incorporates evolutionary-relational models with techniques and practices of Applied Behavioral Analysis and Pivotal Responsive Training.
Starting from this model in 2017 it has been developed, by Giacomo Vivanti, Ed Duncan, Geraldine Dawson and Sally J. Rogers, the Group-Based Early Start Denver Model, intervention model implemented in kindergarten and aimed at children with autism. It is precisely this model that focuses on the feasibility study presented in this work.
The research work is configured as a feasibility study aimed at investigating, through the analysis of the scientific literature of reference, the acceptability, implementation, adaptation and integration of the Group-Based Early Start Denver Model within the school of Italian childhood.
A feasibility study conducted starting from the analysis of the presented elements represents, in agreement with the principles of the Index for Inclusion, the first step for the development of a possible future research: even before planning an experimentation in the didactic field it is essential to reflect on the theories underlying the model, on the socio-cultural values that the intervention model contains, on the political and legislative constraints that could hinder experimentation and declinability. [edited by Author]XVI n.s
From theory to the complex geospatial ground-truth of contaminated soils.
No full textCharacterization and subsequent reclamation of contaminated sites require detailed knowledge of the geospatial distribution of contamination. In Italy, a potentially contaminated site is an area where the concentration of one or more contaminants in soils is above land-use legal limits (CSC according to Italian law 152/06). Four main phases have to be followed to assess contamination and then reclamation: 1) preliminary conceptual model, 2) characterization plan, 3) site specific risk analysis (by Risk-net software) setting the contamination threshold concentration (CSR), 4) assessment of contamination and therefore reclamation action by comparison between CSC and CSR. The geospatial distribution of contaminants is considered in the characterization plan. It is mandatory to sample at least three samples for each surveyed point (one sample in the 0 to 1 m depth, one sample in the capillary fringe zone and one in between). There aren’t clear indications on the sampling strategy and spatial density. According to Italian law (D.M. 471/99), it is usual to identify 5 to 15 sampling points for areas of 1 to 5 hectares.
In this work we attempt to answer the question: “After more than a decade from the introduction of law 152/06 and considering the progress of scientific knowledge, are these soil sampling criteria suitable for assessing the spatial and volumetric distribution of site contamination?
We considered the analytical and spatial dataset obtained from two rural and industrial potentially polluted sites of south Italy, formerly interested by past disposal of industrial sludge and wastes.
In both sites results showed that: (i) the geospatial variability of contamination is always much more complex than expected and depends by the history of the contamination; (ii) the sampling of the first meter - as a single body - is not satisfactory because it does not take into account the real vertical distribution of pollutants and the soil stratigraphy (such as the presence of centimeter horizons).
The work illustrates the use of proximal sensing sensors, such as EMI, ARP, portable gamma-ray spectrometers and portable XRFs to obtain detailed mappings for homogeneous areas identification, where to address subsequent pedological and chemical investigations.
Moreover, the pedological observation - guided by these technologies - often provides essential information to understand the process of emplacement and possible migration of pollutants towards other environmental sectors. The applied integrated approach, which was found very relevant for the site characterization, can assume even greater importance in the subsequent phase of reclamation
A Safe and Multitasking Antimicrobial Decapeptide: The Road from De Novo Design to Structural and Functional Characterization
No full textAntimicrobial peptides (AMPs) are excellent candidates to fight multi-resistant pathogens worldwide and are considered promising bio-preservatives to control microbial spoilage through food processing. To date, designing de novo AMPs with high therapeutic indexes, low-cost synthesis, high resistance, and bioavailability, remains a challenge. In this study, a novel decapeptide, named RiLK1, was rationally designed starting from the sequence of the previously characterized AMP 1018-K6, with the aim of developing short peptides, and promoting higher selectivity over mammalian cells, antibacterial activity, and structural resistance under different salt, pH, and temperature conditions. Interestingly, RiLK1 displayed a broad-spectrum of bactericidal activity against Gram-positive and Gram-negative bacteria, including multidrug resistant clinical isolates of Salmonella species, with Minimal Bactericidal Concentration (MBC) values in low micromolar range, and it was effective even against two fungal pathogens with no evidence of cytotoxicity on human keratinocytes and fibroblasts. Moreover, RiLK1-activated polypropylene films were revealed to efficiently prevent the growth of microbial spoilage, possibly improving the shelf life of fresh food products. These results suggested that de novo designed peptide RiLK1 could be the first candidate for the development of a promising class of decameric and multitask antimicrobial agents to overcome drug-resistance phenomena
Unusual Antioxidant Properties of 26S Proteasome Isolated from Cold-Adapted Organisms
No full textThe oxidative challenge represents an important factor affecting the adaptive strategies in Antarctic fish, but their impact on the protein degradation machinery still remains unclear. The previous analysis of the first 26S proteasome from the Antarctic red-blooded fish Trematomus bernacchii, evidenced improved antioxidant functions necessary to counteract the environmental pro-oxidant conditions. The purpose of this work was to carry out a study on 26S proteasomes from the temperate red-blooded Dicenthrarcus labrax and the icefish Chionodraco hamatus in comparison with the isoform already described from T. bernacchii, to better elucidate the cold-adapted physiological functions of this complex. Therefore, the 26S isoforms were isolated and the complementary DNAs (cDNAs) codifying the catalytic subunits were cloned. The biochemical characterization of Antarctic 26S proteasomes revealed their significantly higher structural stability and resistance to H2O2 with respect to that of the temperate counterpart, as also suggested by a comparative modeling analysis of the catalytic subunits. Moreover, in contrast to that observed in T. bernacchii, the 26S systems from C. hamatus and D. labrax were incapable to hydrolyze oxidized proteins in a ubiquitin-independent manner. Therefore, the ‘uncommon’ properties displayed by the Antarctic 26S proteasomes can mirror the impact exercised by evolutionary pressure in response to richly oxygenated environments
