Autochthonous Lactobacillus paracasei subsp. paracasei strains isolated from Caciocavallo cheese: identification and in-vitro investigation on potential probiotic and functional properties

Background: In recent years consumers, due to the growing interest for functional foods, have put particularly a ention on prod- ucts enriched with probiotic lactic acid bacteria for their ability to give human bene t by their assumption. Microorganisms to be considered as probiotic should be able to survive to gastrointestinal juices and colonize the intestinal tract to provide bene ts to human health. The aim of the study consisted on the in vitro investigation of novel LAB strains, isolated during cheesemaking and ripening of Caciocavallo cheese, and on their probiotic potential for food application. Methods: In order to select potential probiotic bacteria, LAB isolates were preliminarily screened for their survival to simulated gastro-intestinal transitand assayed for others activities of probiotic and functional interest. Thanks to promising a itude as poten- tial probiotics, four strains were tested to evaluate their adhesion ability on Caco-2 cell lines used as intestinal cell model. Microbiological data were analysed by one-way analysis of variance (ANOVA). Comparisons of means were carried out using post-hoc Tukey’s test. For vitro adhesion experiments, statistical signi cance was evaluated by Kruskal-Wallis test for equal medi- ans. Results: Twenty- ve LAB, presumptively identi ed as Lactobacillus spp., were isolated from cheese during 60 days of ripening and screened for their survival to simulated gastrointestinal transit. Sixteen isolates that showed a survival rate ≥85% were identi edas 10 di erent pro les of Lb. paracasei subsp. paracasei. The 10 strains tolerated high concentration of bile salts by Minimal Inhibitory Concentration and growth rate assays and showed susceptibility or moderate susceptibility against antibiotics of human and vet- erinary importance, except for the resistanceto the class of aminoglycoside antibiotics. Eight out 10 strains showed in vitro choles- terol-lowering ability, whereas all strains showed antioxidant activity of their cell-free supernatants. Moreover, the four strains with highest survival to simulated gastrointestinal transit showed the ability to adhere to Caco-2 cells. Conclusion: The results suggest that some strains may be e ective probiotics to be use as tool to design probiotic dairy products after con rmation probiotic activities in further in vivo studies. Findings of the present study suggest that four strains showed good or strong adherent ability on Caco-2 cell monolayer, that is one of prerequisite that probiotic bacteria must have to perform their functional properties

Scanning Probe Microscopy for polymer film characterization in food packaging

Scanning probe microscopy (SPM) is a branch of microscopy allowing characterization of surfaces at the micro-scale by means of a physical probe (with a size of a few microns) raster scanning the sample. SPMs monitor the interaction between such probe and the surface and, depending on the specific physical principles causing the interaction, they allow generation of a quantitative map of topographic properties: geometrical, optical, electrical, magnetic, etc. This is of the greatest interest, in particular whenever functional surfaces have to be characterized in a quantitative manner. The present paper discusses the different applications of Scanning Probe Microscopy techniques for a thorough characterization of polymer surfaces, of specific interest in particular for the case of food packaging applications

Of illness and cures : concepts of health in early modern Malta

In early modern Malta, as in the rest of Europe, there existed two major systems by which one could explain health and sickness, life and death or, general success and failure in everyday life. The first was based on the general belief that God's omnipresence in the world served as an active force in which the good were rewarded and the impious Were punished. God showed his hand on the malevolence of the world in the devastation caused by warring activities or, the infliction of famine and plague. It was believed that the only way these scourges could be controlled was by resorting to supernatural power, Belief in supernatural healing may have been largely circular reasoning but since it was mostly ecclesiastical in nature it was believed to be supernatural and had a vast spiritual and therapeutic effect on the majority of the people. The other view was that put forward by learned medicine, based as it was on natural philosophy, which it largely borrowed from the Graeco-Roman world of antiquity and adapted to the Christian tradition. It was a view in which elements and humours were believed to govern everything in the natural world from meteorology to medicine. Pseudo-sciences such as astrology, magic and alchemy formed an integral part of this worldview and claimed to offer ways to understand and control the environment. In essence learned medicine was little different from popular magical healing since the practitioners had no real understanding of the circulation of blood, the nervous system, the digestive system nor anything else. The prescriptions they prepared were of little or no help and were indeed often potentially lethal. In order to give the impression that they were doing something useful physicians normally subjected their patients to a regime of emetics, purges and bleeding, as the normal forms of intervention available. Nonetheless one must admit that for all its weaknesses the medicinal healing of the times had a very powerful effect on the worldview of people from all social levels. In short the sixteenth and seventeenth centuries were a time when the appeal of medical knowledge was almost entirely influenced by classical texts based on Greek, and to some extent Roman, popular knowledge. Medical practice was essentially based on Galenic medicine, which changed very little over the centuries until the late eighteenth century.peer-reviewe

II Convegno della medievistica italiana. Matera, 13-16 giugno 2022

La Sismed, Società italiana per la storia medievale, ha organizzato tra il 13 e il 16 giugno del 2022 il secondo convegno della medievistica italiana negli spazi del Campus universitario di Matera. L’iniziativa è stata articolata in 61 panel tematici cui hanno preso parte più di 200 studiosi – a diversi stadi della loro carriera universitaria – tra coordinatori, relatori e discussant. La Sismed ha deciso di mettere a disposizione della comunità scientifica i primi esiti di quasi tutti i panel, che testimoniano larga parte dei temi vivi nella medievistica italiana del secondo decennio del secolo: si leggono qui le relazioni presentate nel corso del convegno, in una versione preliminare a una rielaborazione in forma più distesa e completa – arricchita dal contributo di dibattito seguito alle esposizioni nei panel – e in vista di una eventuale e più tradizionale pubblicazione. Gli autori sono stati lasciati liberi di consegnare i propri lavori nella modalità di loro maggior gradimento, spesso senza note e bibliografia e talora nella semplice forma di abstract. Il deposito di tale assemblaggio non selettivo (mancano solo i testi di chi ha lecitamente preferito non consegnare) nell’Open Archive di Reti Medievali ha la funzione di tutelare questo patrimonio intellettuale e il diritto di ciascun autore. I panel sono presentati nella successione che si legge nella locandina del convegno (fatti salvi i panel doppi), qui riprodotta in calce al pdf cumulativo

Physical properties and antimicrobial activity of bioactive film based on whey protein and Lactobacillus curvatus 54M16 producer of bacteriocins

The objective of the work was to study the viability and antimicrobial activity of bacteriocin-producing lactic acid bacteria (LAB) incorporated into whey protein/inulin/gelatine (WP) edible films in presence or absence of nutrient (modified MRS broth). Moreover, the role of the cell on the film structure and properties has been investigated. The results of the work showed that WP-based films were able to ensure a high viability of the bacteriocin-producing strain L. curvatus 54M16 during 28 days of storage at 4 �C. The addition of nutrient in the film matrix slightly affected the viability of the cells, but it was critical for the antimicrobial activity of the films. Films in presence of nutrient showed a good antimicrobial activity against L. innocua C6 as in vitro system as on cooked ham. The presence of LAB has a significant effect on the structure of the film: it reduced the viscosity of the film forming solution and improved the elasticity and the percentage of elongation. Whereas, no effect was observed for water vapour transmission rate and solubility. Thus, WP-based films in presence of modified MRS broth can be used as effective delivery and carrier systems for lactic acid bacteria to develop bioactive edible film or coating with antimicrobial properties

Physical properties and antimicrobial activity of bioactive film based on whey protein and Lactobacillus curvatus 54M16 producer of bacteriocins

The objective of the work was to study the viability and antimicrobial activity of bacteriocin-producing lactic acid bacteria (LAB) incorporated into whey protein/inulin/gelatine (WP) edible films in presence or absence of nutrient (modified MRS broth). Moreover, the role of the cell on the film structure and properties has been investigated. The results of the work showed that WP-based films were able to ensure a high viability of the bacteriocin-producing strain L. curvatus 54M16 during 28 days of storage at 4 °C. The addition of nutrient in the film matrix slightly affected the viability of the cells, but it was critical for the antimicrobial activity of the films. Films in presence of nutrient showed a good antimicrobial activity against L. innocua C6 as in vitro system as on cooked ham. The presence of LAB has a significant effect on the structure of the film: it reduced the viscosity of the film forming solution and improved the elasticity and the percentage of elongation. Whereas, no effect was observed for water vapour transmission rate and solubility. Thus, WP-based films in presence of modified MRS broth can be used as effective delivery and carrier systems for lactic acid bacteria to develop bioactive edible film or coating with antimicrobial properties

Linking bacterial and eukaryotic microbiota to litter chemistry: Combining next generation sequencing with 13 C CPMAS NMR spectroscopy

Microbial succession over decomposing litter is controlled by biotic interactions, dispersal limitation, grazing pressure, and substrate chemical changes. Recent evidence suggests that the changes in litter chemistry and microbiome during decomposition are interdependent. However, most previous studies separately addressed the microbial successional dynamics or the molecular changes of decomposing litter. Here, we combined litter chemical characterization by 13 C NMR spectroscopy with next generation sequencing to compare leaf litter chemistry and microbiome dynamics using 30 litter types, either fresh or decomposed for 30 and 180 days. We observed a decrease of cellulose and C/N ratio during decomposition, while lignin content and lignin/N ratio showed the opposite pattern. 13 C NMR revealed significant chemical changes as microbial decomposition was proceeding, with a decrease in O-alkyl C and an increase in alkyl C and methoxyl C relative abundances. Overall, bacterial and eukaryotic taxonomical richness increased with litter age. Among Bacteria, Proteobacteria dominated all undecomposed litters but this group was progressively replaced by members of Actinobacteria, Bacteroidetes, and Firmicutes. Nitrogen-fixing genera such as Beijerinckia and Rhizobium occurred both in undecomposed as well as in aged litters. Among Eukarya, fungi belonging to the Ascomycota phylum were dominant in undecomposed litter with the typical phyllospheric genus Aureobasidium. In aged litters, phyllospheric species were replaced by zygomycetes and other ascomycetous and basidiomycetous fungi. Our analysis of decomposing litter highlighted an unprecedented, widespread occurrence of protists belonging to the Amebozoa and Cercozoa. Correlation network analysis showed that microbial communities are non-randomly structured, showing strikingly distinct composition in relation to litter chemistry. Our data demonstrate that the importance of litter chemistry in shaping microbial community structure increased during the decomposition process, being of little importance for freshly fallen leaves

Animal rennets as sources of dairy lactic acid bacteria

The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus lactis, Lactobacillus delbrueckii, and Streptococcus thermophilus, while the other strains, all belonging to the genus Enterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions