2,406 research outputs found
Preliminary evaluation of probiotic properties of Lactobacillus strains isolated from Sardinian dairy products
Twenty-three Lactobacillus strains of dairy origin were evaluated for some functional properties relevant to their use as probiotics. A preliminary subtractive screening based on the abilities to inhibit the growth of microbial pathogens and hydrolyze conjugated bile salts was applied, and six strains were selected for further characterization including survival under gastrointestinal environmental conditions, adhesion to gut epithelial tissue, enzymatic activity, and some safety properties. All selected strains maintained elevated cell numbers under conditions simulating passage through the human gastrointestinal tract, well comparable to the values obtained for the probiotic strain Lactobacillus rhamnosus GG, and were able to adhere to Caco-2 cells to various extents (from 3 to 20%). All strains exhibited high aminopeptidase, and absent or very low proteolytic and strong β-galactosidase activities; none was found to be haemolytic or to produce biogenic amines and all were susceptible to tetracycline, chloramphenicol, erythromycin, ampicillin, and amoxicillin/clavulanic acid. Our results indicate that the Lactobacillus strains analyzed could be considered appropriate probiotic candidates, due to resistance to GIT simulated conditions, antimicrobial activity, adhesion to Caco-2 cell-line, and absence of undesirable properties. They could be used as adjunct cultures for contributing to the quality and health related functional properties of dairy products
Geohazard features of the Southern Sardinia
The Maps of Geohazard features of Southern Sardinia produced in the framework of the Magic project (MArine Geohazard along Italian Coasts) are here presented. The MaGIC project (Marine Geohazard along the Italian Coasts) had the aim of mapping the geohazard in the Italian seas. The features were derived from the digital elevation model interpretation of the seafloor morphology and shallow sub-surface. From the marine geo-hazards point of view, the main critical elements are represented by gravitational mass processes in the canyon heads, some of which, as in the Toro Canyon, are exposed to seismic triggering. In other cases, we observed that gravitational dynamics connected to fluid leakage processes (pockforms). Large landslides and debris avalanches have been detected in Cagliari Gulf, whereas in eastern upper slope, crescent bedforms, occurring in the eastern sector of the upper slope testify to the upward migration of hyperpycnal erosional structures linked to flows from nearby river inputs
Identification of two new repetitive elements and chromosomal mapping of repetitive DNA sequences in the fish Gymnothorax unicolor (Anguilliformes: Muraenidae)
Muraenidae is a species-rich family, with relationships among genera and species and taxonomy that have not been completely clarified. Few cytogenetic studies have been conducted on this family, and all of them showed the same diploid chromosome number (2n=42) but with conspicuous karyotypic variation among species. The Mediterranean moray eel Gymnothorax unicolor was previously cytogenetically studied using classical techniques that allowed the characterization of its karyotype structure and the constitutive heterochromatin and argyrophilic nucleolar organizer regions (Ag-NORs) distribution pattern. In the present study, we describe two new repetitive elements (called GuMboI and GuDdeI) obtained from restricted genomic DNA of G. unicolor that were characterized by Southern blot and physically localized by in situ hybridization on metaphase chromosomes. As they are highly repetitive DNA sequences, they map in heterochromatic regions. However, while GuDdeI was localized in the centromeric regions, the GuMboI fraction was distributed on some centromeres and was co-localized with the nucleolus organizer region (NOR). Comparative analysis with other Mediterranean species such as Muraena helena pointed out that these DNA fractions are species-specific and could potentially be used for species discrimination. As a new contribution to the karyotype of this species, we found that the major ribosomal genes are localized on acrocentric chromosome 9 and that the telomeres of each chromosome are composed of a tandem repeat derived from a poly-TTAGGG DNA sequence, as it occurs in most vertebrate species. The results obtained add new information useful in comparative genomics at the chromosomal level and contribute to the cytogenetic knowledge regarding this fish family, which has not been extensively studied
Syngas production, clean-up and wastewater management in a demo-scale fixed-bed updraft biomass gasification unit
This paper presents the experimental development at demonstration scale of an integrated gasification system fed with wood chips. The unit is based on a fixed-bed, updraft and air-blown gasifier-with a nominal capacity of 5 MWth-equipped with a wet scrubber for syngas clean-up and an integrated chemical and physical wastewater management system. Gasification performance, syngas composition and temperature profile are presented for the optimal operating conditions and with reference to two kinds of biomass used as primary fuels, i.e., stone pine and eucalyptus from local forests (combined heat and power generation from this kind of fuel represents a good opportunity to exploit distributed generation systems that can be part of a new energy paradigm in the framework of the circular economy). The gasification unit is characterised by a high efficiency (about 79-80%) and an operation stability during each test. Particular attention has been paid to the optimisation of an integrated double stage wastewater management system-which includes an oil skimmer and an activated carbon adsorption filter-designed to minimise both liquid residues and water make-up. The possibility to recycle part of the separated oil and used activated carbon to the gasifier has been also evaluated
Are FGFR and IDH1-2 alterations a positive prognostic factor in intrahepatic cholangiocarcinoma? An unresolved issue
Despite representing some of the most common and investigated molecular changes in intrahepatic cholangiocarcinoma (iCCA), the prognostic role of FGFR and IDH1/2 alterations still remains an open question. In this review we provide a critical analysis of available literature data regarding this topic, underlining the strengths and pitfalls of each study reported. Despite the overall poor quality of current available studies, a general trend toward a better overall survival for FGFR2 rearrangements and, possibly, for FGFR2-3 alterations can be inferred. On the other hand, the positive prognostic role of IDH1/2 mutation seems much more uncertain. In this scenario, better designed clinical trials in these subsets of iCCA patients are needed in order to get definitive conclusions on this issue
Protective effect of hydroxytyrosol and tyrosol metabolites in LPS-induced vascular barrier derangement in vitro
Introduction The maintenance of endothelial barrier function is essential for vasal homeostasis and prevention of cardiovascular diseases. Among the toxic stimuli involved in the initiation of atherosclerotic lesions, Gram negative lipopolysaccharide (LPS) has been reported to be able to trigger endothelial dysfunction, through the alteration of barrier permeability and inflammatory response. Hydroxytyrosol (HT) and tyrosol (Tyr), the major phenolic compounds of extra virgin olive oil (EVOO), as wells as their circulating sulphated and glucuronidated metabolites have been shown to exert anti-inflammatory effects at endothelial level. Methods In this study we investigated the protective effects of HT and Tyr metabolites on LPS-induced alteration of permeability in Human Umbilical Vein Endothelial Cells (HUVEC) monolayers and examined underlying signaling pathways, focusing on tight junction (TJ) proteins, mitogen-activated protein kinase (MAPK) and NOD-, LRR-and pyrin domain-containing protein 3 (NLRP3) inflammasome activation. Results It was shown that LPS-increased permeability in HUVEC cells was due to the alteration of TJ protein level, following the activation of MAPK and NLRP3. HT and Tyr sulphated and glucuronidated metabolites were able to limit the effects exerted by LPS, acting as signaling molecules with an efficacy comparable to that of their precursors HT and Tyr. Discussion The obtained results add a further piece to the understanding of HT and Tyr metabolites mechanisms of action in vascular protection
Ferulic acid metabolites attenuate lps-induced inflammatory response in enterocyte-like cells
Ferulic acid (FA) is a polyphenol pertaining to the class of hydroxycinnamic acids present in numerous foods of a plant origin. Its dietary consumption leads to the formation of several phase I and II metabolites in vivo, which represent the largest amount of ferulates in the circulation and in the intestine in comparison with FA itself. In this work, we evaluated their efficacy against the proinflam-matory effects induced by lipopolysaccharide (LPS) in intestinal Caco-2 cell monolayers, as well as the mechanisms underlying their protective action. LPS-induced overexpression of proinflammatory enzymes such as inducible nitric oxide synthase (iNOS) and the consequent hyperproduction of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) were limited by physiological relevant concentrations (1 µM) of FA, its derivatives isoferulic acid (IFA) and dihydroferulic acid (DHFA), and their glucuronidated and sulfated metabolites, which acted upstream by limiting the activation of MAPK p38 and ERK and of Akt kinase, thus decreasing the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation into the nucleus. Furthermore, the compounds were found to promote the expression of Nrf2, which may have contributed to the downregulation of NF-kB activity. The overall data show that phase I/II metabolites retain the efficacy of their dietary free form in contrasting inflammatory response
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