Produzione di ubichinoni in batteri appartenenti alla famiglia delle Rhizobiaceae

La presenza nella dieta di sostanze ad attività antiossidante può aiutare a prevenire patologie cardiache e tumori, ridurre la pressione arteriosa e rallentare gli effetti dell’invecchiamento. Si tratta di sostanze capaci di regolare molteplici processi cellulari chiave, quali proliferazione cellulare e apoptosi, nonché di contrastare a vari livelli il danno causato dai radicali liberi (ROS, Reactive Oxigen Species). Tra le sostanze capaci di inattivare direttamente i ROS troviamo il Coenzima Q o ubichinone-10 a cui sono state attribuite, negli ultimi anni, sempre nuove proprietà benefiche per l’organismo. L’attuale produzione industriale di Coenzima Q avviene principalmente mediante sintesi chimica o per estrazione diretta da lieviti. In questo lavoro di tesi sono stati studiati batteri appartenenti alla famiglia delle Rhizobiaceae del genere Agrobacterium, Rhizobium e Mesorhizobium. Sono state valutate le capacità di questi microrganismi di produrre ubichinone-10 in diverse condizioni di crescita. Gli ubichinoni intracellulari estratti sono stati analizzati con HPLC. Sono state osservate variazioni in relazione alla temperatura di crescita in tutti i ceppi studiati. L’aumento di temperatura nelle colture batteriche ha portato ad una maggiore produzione specifica (riferita alla massa cellulare secca) di Q-10 nella maggior parte dei ceppi. L’impiego di mezzi di coltura complessi di varia composizione può aumentare notevolmente questi valori in alcuni ceppi e, al contrario, abbatterla in altri. Una maggiore aerazione delle colture ha portato ad un ulteriore aumento della produzione nei ceppi del genere Agrobacterium e in R. galegae HAMBI-540, M. ciceri HAMBI-1750 e M. plurifarium HAMBI-208

The Microstrain-Doping Phase Diagram of the Iron Pnictides Heterostructures at Atomic Limit

The 3D phase diagram of iron pnictides where the critical temperature depends on charge density and microstrain in the active FeAs layers is proposed. The iron pnictides superconductors are shown to be a practical realization of a heterostructure at the atomic limit made of a superlattice of FeAs layers intercalated by spacer layers. We have focussed our interest on the A 1-x BxFe2As2 (122) families and we show that FeAs layers have a tensile microstrain due to the misfit strain between the active layers and the spacers. We have identified the critical range of doping and microstrain where the critical temperature gets amplified to its maximum value.Comment: 5 pages, 3 figure

Sustainability and Well-Being: The Perception of Younger Generations and Their Expectations

The paper aims at analyzing the level of knowledge and the perception of the concepts of sustainability and well-being of high school students in Tuscany. It is an explorative study carried out during specific events held in high schools with the support of the teachers; during the events, students were asked to fill a questionnaire designed to elicit their relation with these topics as well as the level of involvement of their families. The results provide an interesting starting point for a debate about what the expectations of younger generations are and what we can do to match them. The debate moves from the assessment of the importance of sustainability and well-being indicators and the relevance of perceived threats. Moreover, the results put the role of institutions (and in particular that of public schools) under scrutiny to develop the level of awareness and to promote knowledge transfer

Sustainability and Food: a Text Analysis of the Scientific Literature

The paper analyses the evolution of the research debate related to sustainability and to the relation between food and sustainability. A number of text analysis techniques were combined for the investigation of scientific papers. The results stress how discourse analysis of sustainability in the pre-Rio period is mostly associated with agriculture and with a vision where the ecological and environmental aspects are dominant. In the post-Rio phase, the discussion about sustainability, though still strongly linked to environmental issues, enters a holistic dimension that includes social elements. The themes of energy and the sustainability of urban areas become central, and the scientific debate stresses the importance of indicators within an assessment approach linked to the relevance of planning and intervention aspects. The focus on the role of food within the debate on sustainability highlights a food security oriented approach in the pre-Rio phase, with a particular attention towards agriculture and third world Countries. In the post-Rio period, the focus of the analysis moves towards developed Countries. Even though food security remains a strongly significant element of the debate, the attention shifts towards consumers and food choices

Manipulating electronic states at oxide interfaces using focused micro X-rays from standard lab-sources

Recently, x-ray illumination, using synchrotron radiation, has been used to manipulate defects, stimulate self-organization and to probe their structure. Here we explore a method of defect-engineering low-dimensional systems using focused laboratory-scale X-ray sources. We demonstrate an irreversible change in the conducting properties of the 2-dimensional electron gas at the interface between the complex oxide materials LaAlO3 and SrTiO3 by X-ray irradiation. The electrical resistance is monitored during exposure as the irradiated regions are driven into a high resistance state. Our results suggest attention shall be paid on electronic structure modification in X-ray spectroscopic studies and highlight large-area defect manipulation and direct device patterning as possible new fields of application for focused laboratory X-ray sources.Comment: 12 pages, 4 figure

Misfit Strain in Superlattices Controlling the Electron-Lattice Interaction via Microstrain in Active Layers

High-temperature superconductivity (HTS) emerges in quite different electronic materials: cuprates, diborides, and iron-pnictide superconductors. Looking for unity in the diversity we find in all these materials a common lattice architecture: they are practical realizations of heterostructures at atomic limit made of superlattices of metallic active layers intercalated by spacers as predicted in 1993 by one of us. The multilayer architecture is the key feature for the presence of electronic topological transitions where the Fermi surface of one of the subbands changes dimensionality. The superlattice misfit strain between the active and spacer layers is shown to be a key variable to drive the system to the highest critical temperature that occurs at a particular point of the 3D phase diagram () where is the charge transfer or doping. The plots of as a function of misfit strain at constant charge transfer in cuprates show a first-order quantum critical phase transition where an itinerant striped magnetic phase competes with superconductivity in the proximity of a structural phase transition, that is, associated with an electronic topological transition. The shape resonances in these multigap superconductors is associated with the maximum

New sulfurated derivatives of cinnamic acids and rosmaricine as inhibitors of STAT3 and NF-kappa B transcription factors

A set of new sulfurated drug hybrids, mainly derived from caffeic and ferulic acids and rosmaricine, has been synthesized and their ability to inhibit both STAT3 and NF-kappa B transcription factors have been evaluated. Results showed that most of the new hybrid compounds were able to strongly and selectively bind to STAT3, whereas the parent drugs were devoid of this ability at the tested concentrations. Some of them were also able to inhibit the NF-kappa B transcriptional activity in HCT-116 cell line and inhibited HCT-116 cell proliferation in vitro with IC50 in micromolar range, thus suggesting a potential anticancer activity. Taken together, our study described the identification of new derivatives with dual STAT3/NF-kappa B inhibitory activity, which may represent hit compounds for developing multi-target anticancer agents