A Microbiological characterization of Bifidobacterium spp. strains and a chemical/biological analysis of a exopolysacccharide produc

Lo scopo della ricerca è stato quello di studiare le caratteristiche microbiologiche di ceppi di Bifidobacterium spp. isolati da feci umane e animali e da prodotti probiotici e quello di investigare le proprietà chimico-fisiche e alcune possibili attività biologiche dell esopolisaccaride (EPS) prodotto da un ceppo di Bifidobacterium longum . Gli studi sul profilo metabolico dei ceppi isolati, eseguiti utilizzando sistemi standardizzati, confermavano soltanto per 10 ceppi la probabile appartenenza al genere Bifidobacterium spp. I ceppi caratterizzati come probabili bifidobatteri erano saggiati per la capacità di resistere alle condizioni gastrointestinali e mostravano resistenza a pH 3 e alle differenti concentrazioni di sali biliari saggiate. Inoltre, i 10 ceppi esaminati per la loro sensibilità agli antibiotici mostravano delle MIC compatibili con i valori di cut-off riportati dall EFSA (2012) per il genere Bifidobacterium spp. I probabili bifidobatteri e i ceppi probiotici di Bifidobacterium spp. venivano studiati per la loro capacità di adesione, utilizzando le cellule HT-29, mediante metodo quantitativo colturale e osservazione mediante microscopio ottico ad immersione. I risultati mostravano differenti caratteristiche di adesione in relazione al ceppo saggiato, ma anche in relazione al tempo di incubazione. La capacità di adesione del ceppo Bifidobacterium longum W11 veniva ulteriormente indagata mediante microscopia elettronica a scansione che evidenziava la presenza di biopolimeri di probabile natura esopolisaccaridica, organizzati in una complessa struttura 3D e coinvolti nell adesione del ceppo. Le successive fasi della ricerca erano, quindi, focalizzate sullo studio approfondito di questo biopolimero di natura esopolisaccaridica. Dopo l estrazione, purificazione e idrolisi, utilizzando anche metodiche messe a punto da noi, l esopolisaccaride (EPS) veniva analizzato per la composizione chimica, mediante TLC, utilizzando piastre in silice e in cellulosa. Entrambi i tipi di piastre permettevano di identificare la presenza di glucosio e galattosio, che veniva confermata con una più accurata analisi cromatografica effettuata mediante HPLC. La ricerca dei determinanti genetici responsabili della sintesi dell EPS del ceppo B. longum W11 era effettuata mediante PCR e analisi bioinformatica dell intero genoma. I risultati ottenuti mostravano la presenza del gene cpsD , che codifica per la galactosil-transferasi e un cluster genico composto da 23 geni, (24,7 kb). L attività citotossica veniva saggiata in vitro su fibroblasti gengivali HF1 e tumorali Caco-2. Il saggio su fibroblasti non evidenziava alcun effetto citotossico, mentre quello su cellule tumorali Caco-2 mostrava una modesta diminuzione della vitalità cellulare sin dalla più bassa concentrazione saggiata. Tale decremento, tuttavia non era statisticamente significativo. L eventuale attività immunomodulante dell EPS era analizzata attraverso lo studio del pattern di citochine quali IL-1, IL-6, IL-10 e IFN-gamma, prodotte da cellule immunitarie isolate da PBMC di donatori volontari. I risultati hanno dimostrato per l EPS in esame un effetto di tipo immunomodulante. Inoltre, quando l EPS veniva saggiato in combinazione con ConA si evidenziava un incremento significativo dei livelli di IL-1, IL-6 e IFN-gamma e la riduzione significativa dei livelli di IL-10. I risultati della ricerca forniscono una buona base sperimentale per ulteriori indagini su altri aspetti non ancora investigati degli EPS ed in particolare dell EPS del ceppo B. longum W11, quali l effetto protettivo sul ceppo produttore dalle condizioni intestinali avverse e/o dall attività inibente degli antibiotici o altre eventuali proprietà biologiche

Tuning the wicking and wettability properties of PET textiles by DBD or a remote atmospheric RF torch: A comparison

Textile industry is constantly searching for easy and rapid ways to improve the properties of textiles. In this matter, plasma treatments have already proven to be an efficient and green solution, as they proceed in a dry environment and require minimal use of chemicals. To date, most of the work on the subject has been performed with low-pressure plasmas. Recently, atmospheric plasmas have received increasing interest, especially for industrial applications. Indeed, the possibility to avoid the use of pumping systems makes this technology easily implementable in continuous in-line processes. For many applications, the treatment aims at modifying the textile surface to increase the overall hydrophilicity. The latter is often probed by the water contact angle, but this does not always reflect the global hydrophilic behavior of the textile as a three-dimensional material. A complementary study of the wicking properties is important to better reflect the penetration of liquids into the textile, but it is poorly reported in the literature. The present work aims at increasing the water uptake of polyethylene terephthalate (PET) textile by direct or remote plasma treatment, which are the two main trends in this field. For this purpose, a dielectric barrier discharge (DBD) and a radiofrequency plasma torch at atmospheric pressure are used, respectively. Different plasma parameters are varied and their respective effect on the wicking properties of the fabric, assessed by an absorbency test developed ad hoc, are correlated to their surface chemical composition determined by X-ray photoelectron spectroscopy. These results are compared with the possible changes in wetting of the fiber surface witnessed by water contact angles measured on PET foil samples submitted to the same plasma treatments. Complete wicking of water in PET textile can be obtained after 20 or 10 s of torch treatment with pure Ar plasma or Ar/O2 mixture, respectively. However, a comparable effect is detected, after 30 s of DBD Ar plasma treatment, under the used experimental conditions. Besides, the addition of O2 to the discharge has an opposite effect on the fabric wicking. These results are discussed in terms of the peculiar processes in surface activation and modification of the fabric surface triggered by the two different plasma technologies.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Tuning the wicking and wettability properties of PET textiles by DBD or a remote atmospheric RF torch: A comparison

Textile industry is constantly searching for easy and rapid ways to improve the properties of textiles. In this matter, plasma treatments have already proven to be an efficient and green solution, as they proceed in a dry environment and require minimal use of chemicals. To date, most of the work on the subject has been performed with low-pressure plasmas. Recently, atmospheric plasmas have received increasing interest, especially for industrial applications. Indeed, the possibility to avoid the use of pumping systems makes this technology easily implementable in continuous in-line processes. For many applications, the treatment aims at modifying the textile surface to increase the overall hydrophilicity. The latter is often probed by the water contact angle, but this does not always reflect the global hydrophilic behavior of the textile as a three-dimensional material. A complementary study of the wicking properties is important to better reflect the penetration of liquids into the textile, but it is poorly reported in the literature. The present work aims at increasing the water uptake of polyethylene terephthalate (PET) textile by direct or remote plasma treatment, which are the two main trends in this field. For this purpose, a dielectric barrier discharge (DBD) and a radiofrequency plasma torch at atmospheric pressure are used, respectively. Different plasma parameters are varied and their respective effect on the wicking properties of the fabric, assessed by an absorbency test developed ad hoc, are correlated to their surface chemical composition determined by X-ray photoelectron spectroscopy. These results are compared with the possible changes in wetting of the fiber surface witnessed by water contact angles measured on PET foil samples submitted to the same plasma treatments. Complete wicking of water in PET textile can be obtained after 20 or 10 s of torch treatment with pure Ar plasma or Ar/O2 mixture, respectively. However, a comparable effect is detected, after 30 s of DBD Ar plasma treatment, under the used experimental conditions. Besides, the addition of O2 to the discharge has an opposite effect on the fabric wicking. These results are discussed in terms of the peculiar processes in surface activation and modification of the fabric surface triggered by the two different plasma technologies.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Synergistic Effect of L-Carnosine and Hyaluronic Acid in Their Covalent Conjugates on the Antioxidant Abilities and the Mutual Defense against Enzymatic Degradation

Hyaluronic acid (Hy) is a natural linear polymer that is widely distributed in different organisms, especially in the articular cartilage and the synovial fluid. During tissue injury due to oxidative stress, Hy plays an important protective role. All the beneficial properties of Hy make the polymer attractive for many biomedical uses; however, the low stability and short biological half-life limit Hy application. To overcome these problems, the addition of small antioxidant molecules to Hy solution has been employed to protect the molecular integrity of Hy or delay its degradation. Carnosine (β-alanyl-L-histidine, Car) protects cells from the damage due to the reactive species derived from oxygen (ROS), nitrogen (RNS) or carbonyl groups (RCS). Car inhibits the degradation of hyaluronan induced by free radical processes in vitro but, like Hy, the potential protective action of Car is drastically hampered by the enzymatic hydrolysis in vivo. Recently, we conjugated Hy to Car and the derivatives (HyCar) showed protective effects in experimental models of osteoarthritis and rheumatoid arthritis in vivo. Here we report the antioxidant activity exerted by HyCar against ROS, RNS and RCS. Moreover, we tested if the covalent conjugation between Hy and Car inhibits the enzymatic hydrolysis of the polymer and the dipeptide backbone. We found that the antioxidant properties and the resistance to the enzymatic hydrolysis of Hy and Car are greatly improved by the conjugation

Synergistic Effect of L-Carnosine and Hyaluronic Acid in Their Covalent Conjugates on the Antioxidant Abilities and the Mutual Defense against Enzymatic Degradation

Hyaluronic acid (Hy) is a natural linear polymer that is widely distributed in different organisms, especially in the articular cartilage and the synovial fluid. During tissue injury due to oxidative stress, Hy plays an important protective role. All the beneficial properties of Hy make the polymer attractive for many biomedical uses; however, the low stability and short biological half-life limit Hy application. To overcome these problems, the addition of small antioxidant molecules to Hy solution has been employed to protect the molecular integrity of Hy or delay its degradation. Carnosine (β-alanyl-L-histidine, Car) protects cells from the damage due to the reactive species derived from oxygen (ROS), nitrogen (RNS) or carbonyl groups (RCS). Car inhibits the degradation of hyaluronan induced by free radical processes in vitro but, like Hy, the potential protective action of Car is drastically hampered by the enzymatic hydrolysis in vivo. Recently, we conjugated Hy to Car and the derivatives (HyCar) showed protective effects in experimental models of osteoarthritis and rheumatoid arthritis in vivo. Here we report the antioxidant activity exerted by HyCar against ROS, RNS and RCS. Moreover, we tested if the covalent conjugation between Hy and Car inhibits the enzymatic hydrolysis of the polymer and the dipeptide backbone. We found that the antioxidant properties and the resistance to the enzymatic hydrolysis of Hy and Car are greatly improved by the conjugation

Chemical and biological properties of the novel exopolysaccharide produced by a probiotic strain of Bifidobacterium longum

tBifidobacterium longum W11 is a commercialized probiotic that has an exopolysaccharide (EPS) layercovering its surface which could play a role in the beneficial properties attributed to the strain; thus, wehave carried out chemical and biological analyses of this polymer. The eps cluster putatively involved inthe polymer synthesis presented a unique structural organization not previously reported in bifidobac-teria. B. longum W11 produced a complex polysaccharide blend with the main component composedof glucose and galactose. An exhaustive structural analysis identified two different repeating units: onelinear [→6)--Galf-(1→3)--Galp-(1→] and one, more abundant, with the same backbone in which the-Galf is 5-substituted by a -Glcp unit. The antioxidant capability and the lack of toxicity of the wholeEPS W11 mixture, as well as some functional characteristics of the producing strain, such as the in vitroresistance to gastrointestinal conditions and the adhesion of colonocytes, were also determined

Characterization of <i>Bifidobacterium asteroides</i> Isolates

Bifidobacteria have long been recognized as bacteria with probiotic and therapeutic features. The aim of this work is to characterize the Bifidobacterium asteroides BA15 and BA17 strains, isolated from honeybee gut, to evaluate its safety for human use. An in-depth assessment was carried out on safety properties (antibiotic resistance profiling, β-hemolytic, DNase and gelatinase activities and virulence factor presence) and other properties (antimicrobial activity, auto-aggregation, co-aggregation and hydrophobicity). Based on phenotypic and genotypic characterization, both strains satisfied all the safety requirements. More specifically, genome analysis showed the absence of genes encoding for glycopeptide (vanA, vanB, vanC-1, vanC-2, vanD, vanE, vanG), resistance to tetracycline (tetM, tetL and tetO) and virulence genes (asa1, gelE, cylA, esp, hyl)

Copper(II) Complexes with Carnosine Conjugates of Hyaluronic Acids at Different Dipeptide Loading Percentages Behave as Multiple SOD Mimics and Stimulate Nrf2 Translocation and Antioxidant Response in In Vitro Inflammatory Model

A series of copper(II) complexes with the formula [Cu2+Hy(x)Car%] varying the molecular weight (MW) of Hyaluronic acid (Hy, x = 200 or 700 kDa) conjugated with carnosine (Car) present at different loading were synthesized and characterized via different spectroscopic techniques. The metal complexes behaved as Cu, Zn-superoxide dismutase (SOD1) mimics and showed some of the most efficient reaction rate values produced using a synthetic and water-soluble copper(II)-based SOD mimic reported to date. The increase in the percentage of Car moieties parallels the enhancement of the I50 value determined via the indirect method of Fridovich. The presence of the non-functionalized Hy OH groups favors the scavenger activity of the copper(II) complexes with HyCar, recalling similar behavior previously found for the copper(II) complexes with Car conjugated using β-cyclodextrin or trehalose. In keeping with the new abilities of SOD1 to activate protective agents against oxidative stress in rheumatoid arthritis and osteoarthritis diseases, Cu2+ interaction with HyCar promotes the nuclear translocation of erythroid 2-related factor that regulates the expressions of target genes, including Heme-Oxigenase-1, thus stimulating an antioxidant response in osteoblasts subjected to an inflammatory/oxidative insult