Digital Repository of Hellenic Managing Authority of the Operational Programme "Education and Lifelong Learning" (EDULLL)
Not a member yet
3537 research outputs found
Sort by
Εσωτερική αξιολόγηση προγράμματος: ανάλυση αποτελεσμάτων ερωτηματολογίου αποφοίτων προγράμματος. Επικαιροποίηση γνώσεων αποφοίτων ΑΕΙ στην οργάνωση, διοίκηση τουριστικών επιχειρήσεων και στην προώθηση τουριστικών προορισμών
No full textRelationship between the Indian summer monsoon and the large-scale circulation variability over the Mediterranean
Get PDFIn this study the impact of the Indian summer monsoon on the large scale variability of the atmospheric circulation over the Mediterranean is investigated on an inter-annual time scale. Composite and correlation analysis results are presented, outlining different circulation patterns in the upper and lower troposphere for strong and weak monsoon years respectively. For this purpose ERA-40 Reanalysis monthly mean data at various isobaric levels together with the standardized All India Rainfall Index for boreal summer (June–July–August–September) of a 44- year period were employed. During strong monsoon years many atmospheric circulation systems appear strengthened over Eurasia, resembling a well-organized Rossby wave train over the area. In the upper troposphere a meridional shift of the jet streams over the examined area was also identified during extreme monsoon years. On the other hand, in the lower troposphere enhanced northerlies (Etesians) appear to dominate over Eastern Mediterranean along with intensified subsidence during strong monsoon years
Engineered strains of Streptococcus macedonicus towards an osmotic stress resistant phenotype retain their ability to produce the bacteriocin macedocin under hyperosmotic conditions
No full textStreptococcus macedonicus ACA-DC 198 produces the bacteriocin macedocin in milk only under low NaCl concentrations (<1.0% w/v). The thermosensitive plasmid pGh9:ISS1 was employed to generate osmotic stress resistant (osmr) mutants of S. macedonicus. Three osmr mutants showing integration of the vector in unique chromosomal sites were identified and the disrupted loci were characterized. Interestingly, the mutants were able to grow and to produce macedocin at considerably higher concentrations of NaCl compared to the wild-type (up to 4.0% w/v). The production of macedocin under hyperosmotic conditions solely by the osmr mutants was validated by the well diffusion assay and by mass spectrometry analysis. RT-PCR experiments demonstrated that the macedocin biosynthetic regulon was transcribed at high salt concentrations only in the mutants. Mutant osmr3, the most robust mutant, was converted in its markerless derivative (osmr3f). Co-culture of S. macedonicus with spores of Clostridium tyrobutyricum in milk demonstrated that only the osmr3f mutant and not the wild-type inhibited the growth of the spores under hyperosmotic conditions (i.e., 2.5% w/v NaCl) due to the production of macedocin. Our study shows how genetic manipulation of a strain towards a stress resistant phenotype could improve bacteriocin production under conditions of the same stress
Επίδραση μικροβιακών μορίων-σημάτων επικοινωνίας αυταπαγωγέων-2 στις κινητικές παραμέτρους αύξησης μεμονωμένων κυττάρων Salmonella enterica και του ανθεκτικού στη μεθικιλλίνη Staphylococcus aureus
Get PDFΣκοπός της παρούσας μελέτης ήταν η αξιολόγηση της επίδρασης της δραστηριότητας μορίων-σημάτων διακυτταρικής επικοινωνίας αυτεπαγωγέων-2 (ΑΙ-2) στην κινητική συμπεριφορά αύξησης μεμονωμένων κυττάρων δυο στελεχών Salmonella enterica (ορότυποι Enteritidis και Typhimurium), και ενός στελέχους Staphylococcus aureus ανθεκτικού στη μεθικιλλίνη (MRSA).
The objective of this study was the in vitro evaluation of the effect of autoinducer-2 (AI-2) quorum sensing (QS) signal molecules on the single-cell growth kinetic behavior of two Salmonella enterica strains (serotypes Typhimurium and Enteritidis), and a methicillinresistant Staphylococcus aureus (MRSA) strain
Genomics of Streptococcus macedonicus: moving from pathogenicity to adaptation to the dairy environment
Get PDFBackground: Lactic acid bacteria (LAB constitute a significant group of microorganisms found in foods, but also contribute to human health. The Streptococcus bovis/ Streptococcus equinus complex within LAB includes members that have been implicated in human diseases, like endocarditis and colon cancer.
Objectives: In this study we compared the three available genome sequences of Streptococcus macedonicus strains isolated from dairy products. Only one strain has its genome complete sequenced and previous analysis showed diminished pathogenic potential and adaptation to the milk environment. Here we present the in silico analysis of these strains, in order to better understand the S. macedonicus species.
Methods: Chromosomal maps were constructed using DNA Plotter and whole genome sequence alignments were performed by progressiveMAUVE and Webact in order to visualize conserved genomic regions or chromosomal rearrangements. Genomic islands were identified and visualized by IslandViewer, potential bacteriocins were predicted by BAGEL3 and CRISPRs were analyzed by the tools available in the CRISPRcompar web-service.
Conclusions: The analysis revealed that the strains have lost genes involved in the catabolism of complex plant carbohydrates, in the adhesion to the host’s cells and in haemolysis. On the other hand, an extra lactose operon and a proteolytic system characteristic of LAB were identified. Even though our whole genome analysis of S. macedonicus shows adaptation traits to the nutrient-rich dairy environment, analysis of additional S. macedonicus genomes, including non-dairy isolates, may be necessary to clarify its pathogenic potential
In silico design of 2,2'-dihydroxybenzophenones and xanthone analogues to inhibit human glutathione transferase's (hGSTs) involvement in Multiple Drug Resistance.
Get PDFGlutathione S-transferases catalyze the conjugation of glutathione (GSH) to a variety of hydrophobic substrates, rendering them hydrophilic and facilitating their metabolic processing and secretion from the cell. GSTs are involved in major detoxification mechanisms of the cell from several xenobiotics and drugs. On the other hand, on the basis of the same detoxification mechanisms, cancer cells may acquire resistance by overexpressing GST activities, thus hampering the effectiveness of certain chemotherapeutic drugs and leading to chemotherapeutic resistant tumor cells. Several synthetic drugs and prodrugs exhibiting inhibition potency against GSTs have been proposed as strategies to overcoming multiple drug resistance (MDR) attributed to GST overexpression. In the pursuit of identifying new lead compounds as inhibitors against hGSTs involved in MDR we have used Structure Based Ligand Design techniques to generate in silico xanthone and benzophenone derivatives and performed extensive molecular docking and binding evaluation on the structure of hGSTA1-1
The effects of dietary hesperidin and naringin supplementation on lamb performance and meat characteristics
Get PDFAn experiment was conducted to examine the effects of supplementing feed with hesperidin or naringin, bioflavonoids that are abundant and inexpensive by-products of citrus cultivation, on lambs’ growth performance, carcass and meat characteristics. Fourty-four male Chios lambs were randomly assigned to 4 groups. One of the groups served as control (C) and was given a basal diet, whereas the other 3 groups were given the same diet further supplemented with hesperidin at 2500 mg (H), or naringin at 2500 mg (N), or α-tocopheryl acetate at 200 mg (E) per kg feed. At the end of the experiment (35th day), lambs were fasted, weighed and slaughtered. After overnight chilling, samples of longissimus thoracis muscle were taken and were used for meat quality evaluation.
No significant differences were observed in final body weight, body weight gain and edible organ weights among the four experimental groups. pH, colour parameters (L, a*, b*), water holding capacity and shear force value of longissimus thoracis muscle were also not significantly influenced by the dietary treatments. Measurement of lipid oxidation values showed that hesperidin or naringin supplementation positively influenced meat antioxidant properties during the refrigerated storage at 4°C for up to 8 days, however to a lesser extent compared to α-tocopheryl acetate.
Nowadays, there is a strong interest in isolating antioxidants from natural sources and using them in animal nutrition with the intention to minimize lipid oxidation in meat products. According to the findings of the present study, flavonoids appeared as a great alternative, since they resulted in an improvement of meat antioxidant capacity leading to a prolongation of its shelf-life and an increase of its acceptability in the market
Cloning and characterization of herbicide-degrading glutathione transferases from cicer arietinum
Get PDFGSTs are multifunctional enzymes that catalyze the conjugation of glutathione (GSH) to reactive electrophiles. These electrophiles are diverse and include important endogenous compounds, as well as xenobiotic chemicals, therefore GSTs play an important role in stress tolerance and herbicide detoxification. GSTs are usually active as a dimer of 24–29 kDa subunits. Each monomer of dimeric GSTs contains a G-site, at the N-terminal, capable of binding the GSH substrate and an H-site, at the C-terminal, that has xenobiotic compound-binding capabilities. Different classes of herbicides such as triazines, thiocarbamates, chloroacetanilides, diphenylethers, and aryloxyphenoxypropionates can be metabolized by GSTs. Herbicide tolerance in plants is based primarily on the differential ability of plant species to detoxify a herbicide, with the formation of a herbicide-GSH conjugate in the resistant but not in the susceptible species. The plant-specific phi and tau GSTs are primarily responsible for herbicide detoxification, showing class specificity in substrate preference. In present work, we report the cloning, kinetic and structural characterization of three members of the GST family from Cicer arietinum leaves (CaGSTs)