1,332 research outputs found
Chemical and biological changes in sludge stabilization with different oxygenation patterns
No full text
Effect of itraconazole on Staphylococcus aureus biofilm and extracellular vesicles formation
No full textStaphylococcus aureus is a leading cause of a wide range of clinical chronic infections mainly due to the establishment of a biofilm. Biofilm, a population of bacteria within a self-produced matrix of extracellular polymeric substance, decreases the susceptibility to antibiotics, immune defenses and contributes to antimicrobial resistance. To date antibiotic combination has been considered a strategy to combat S. aureus infection, but this approach does not solves the main pharmacokinetic problem caused by biofilms, consisting in insufficient drug penetration within the structure. Therefore, new antimicrobial agents that could overcome this resistance need to be discovered. Fighting staphylococcal resistance and biofilm formation is an important goal of the pharmaceutical research. Some fungicide has been observed to have antibacterial effect. anyway their use as antibiotics on S.aureus has been poorly studied. The aim of this work was to investigate the effect of the fungicide itraconazole (IT) on S. aureus biofilm formation and explore by SEM the morphological alteration after treatment. A strong biofilm disaggregation and morphologically different extracellular vesicles (EV) production were observed starting from sublethal IT doses. This suggests that IT resistance phenomena on the part of S. aureus are more difficult to establish respect other antibiotics. The adjuvant properties of IT could be used to combat bacterial biofilm and/or to improve antibiotic treatment. Moreover, because the production of EV represents a secretory pathway involved in intercellular communication shared to mammalian cells, fungi, and bacteria, our study is important to increase information that can be generalized to higher organisms
The influence of spatial coordinates in a case of an optic ataxia like syndrome following cerebellar and thalamic lesion
No full textWe report the case of a patient (S. C.) who, after a lesion involving the midbrain, thalamus, and cerebellum on the left side, was unable to reach a target at which he was not directly gazing. When attempting to do so with either hand, he showed an optic ataxia-like behaviour: A rightward deviation was manifest with respect to the real position of the target object, accuracy being worse for the right than for the left hand and for the right than for the left hemifield. To assess whether S.C.'s reaching accuracy was affected by the position of the target with respect to the retina, eyes, and/or head, he was asked to perform a pointing task in different conditions. By manipulating eyes and head position, the relative location of the target with respect to these body parts was altered. Further, to verify the relevance of the visual feedback for the accuracy of the reaching responses, the task was also performed either with or without vision of the performing hand (closed- and open-loop conditions). The results showed that the patient's reaching impairment reflects a deficit in spatio-motor coding mainly within head-centred coordinates. The lack of visual feedback about the hand spatial location worsened the reaching performance. This new pattern of reaching deficits is discussed in relation to the theoretical framework of both parietal optic ataxia and cerebellar ataxia
Ponti esperienziali
No full textNei servizi educativi comunali rivolti a bambini da 0 a 3 anni la costruzione dei percorsi progettuali è tesa a sostenere lo sviluppo degli apprendimenti, con uno sguardo finalizzato a valorizzare le connessioni tra i saperi e le teorie in divenire e gli intrecci tra i differenti linguaggi. All'interno di tali percorsi alcuni aspetti meritano di essere messi in luce proprio in relazione alle strategie e alle metodologie messe in atto per promuovere lo sviluppo del pensiero creativo nell'infanzia
Biodegradation of dibenzothiophene by a bacterial isolated of Burkholderia sp. strain dbt1
No full textGenotoxicity of 4-nonylphenol and nonylphenol ethoxylate mixtures with the use of Saccharomyces cerevisiae D7 mutation assay and use of this text to evaluate the efficiency of biodegradation treatments.
No full textNonylphenol ethoxylates (NPnEOs, n is the number of ethoxylic units in the molecule) are non-ionic surfactants widely used in several industrial applications, such as textile and leather processing, paper industry, formulation of pesticides, paints and washing cleaners. 4-Nonylphenol (4-NP), the main product of NPnEO biodegradation, is a toxic xenobiotic compound classified as endocrine disrupter. While numerous studies reported the toxicity and estrogenic activity of nonylphenols, little is known about the mutagenicity of these compounds. In this paper, the genotoxicity of 4-NP and NPnEO mixtures was evaluated by using the D7 strain of Saccharomyces cerevisiae as experimental model. The same tests were applied to effluents deriving from laboratory scale packed-bed bioreactors, developed for the treatment of NPnEO contaminated wastewater, in order to evaluate the residual genotoxic potential with respect to the influent waste. The target compounds fed to the bioreactors were 4-NP and NPnEO mixtures possessing an average of 5 or 1.5 ethoxylic units (Igepal CO-520 and Igepal CO-210, respectively). The results showed that 4-NP induced significant cytotoxic effect on S. cerevisiae cells at 60 mg/L, as well as mutagenic effects at 15 and 30 mg/L. 4-NP was the most genotoxic compound among those assayed, followed by Igepal CO-210, whereas Igepal CO-520 did not induce genotoxicity at any of the assayed concentrations. The genotoxic effects evidenced on yeast cells treated with 4-NP disappeared after the treatment in the bioreactor. This indicates that the biological treatment is capable of removing not only the pollutant, but also the toxicity associated to the compound and its degradation metabolites. This study represents, to the best of our knowledge, the first report that evaluates the genotoxicity of both 4-NP, NPnEOs and their potential aerobic degradation products on an eukaryotic organism. The obtained results suggest that the S. cerevisiae D7 strain is a very effective model to study the induction of genotoxic damage by the compounds under study. In addition, this method is much more simpler and easier to be applied than other tests described in the literature to study genotoxic effects. Moreover, the test described in this work has also proven to be effective in evaluating the toxicity of effluents deriving from laboratory scale biotreatment processes. It would be really interesting to apply the described tests on real wastewater treatment system in order to estimate the detoxification potential of the process applied, which is often not directly correlated with the removal of the target pollutant
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