Insights into the Transposable Mobilome of Paracoccus spp. (Alphaproteobacteria)

Several trap plasmids (enabling positive selection of transposition events) were used to identify a pool of functional transposable elements (TEs) residing in bacteria of the genus Paracoccus (Alphaproteobacteria). Complex analysis of 25 strains representing 20 species of this genus led to the capture and characterization of (i) 37 insertion sequences (ISs) representing 9 IS families (IS3, IS5, IS6, IS21, IS66, IS256, IS1182, IS1380 and IS1634), (ii) a composite transposon Tn6097 generated by two copies of the ISPfe2 (IS1634 family) containing two predicted genetic modules, involved in the arginine deiminase pathway and daunorubicin/doxorubicin resistance, (iii) 3 non-composite transposons of the Tn3 family, including Tn5393 carrying streptomycin resistance and (iv) a transposable genomic island TnPpa1 (45 kb). Some of the elements (e.g. Tn5393, Tn6097 and ISs of the IS903 group of the IS5 family) were shown to contain strong promoters able to drive transcription of genes placed downstream of the target site of transposition. Through the application of trap plasmid pCM132TC, containing a promoterless tetracycline resistance reporter gene, we identified five ways in which transposition can supply promoters to transcriptionally silent genes. Besides highlighting the diversity and specific features of several TEs, the analyses performed in this study have provided novel and interesting information on (i) the dynamics of the process of transposition (e.g. the unusually high frequency of transposition of TnPpa1) and (ii) structural changes in DNA mediated by transposition (e.g. the generation of large deletions in the recipient molecule upon transposition of ISPve1 of the IS21 family). We also demonstrated the great potential of TEs and transposition in the generation of diverse phenotypes as well as in the natural amplification and dissemination of genetic information (of adaptative value) by horizontal gene transfer, which is considered the driving force of bacterial evolution

Percorsi di Media Education

L\u2019introduzione dei media rappresenta per la scuola un\u2019occasione di cambiamento non solo sul piano della strumentazione materiale, attraverso cui gestire i processi di insegnamento/apprendimento, ma soprattutto per riflettere su tali processi e innovarli in maniera consapevole e critica. I media possono facilitare negli alunni l\u2019acquisizione della consapevolezza dei propri processi mentali e far acquisire una maggiore libert\ue0 di gestione del proprio processo di apprendimento; se ben utilizzati i media a scuola possono, rendere pi\uf9 visibili le scelte, le associazioni mentali, il modo di affrontare le situazioni problematiche e le procedure operative che caratterizzano i processi mentali di ogni alunno. L\u2019ambito pi\uf9 adeguato per promuovere negli alunni l\u2019autoregolazione del proprio apprendimento \ue8 la media education, che coinvolge e stimola abilit\ue0 complesse, operando sia sullo sviluppo della mente sia su quello delle emozioni e delle relazioni. La media education, ad oggi, non \ue8 pienamente presente e realizzata nell\u2019azione didattica della scuola italiana. Tuttavia, l\u2019era digitale e l\u2019arrivo dei new media stanno rivoluzionando l\u2019intero sistema della comunicazione, ridefinendone in profondit\ue0 sia gli strumenti sia le modalit\ue0 di consumoMedia represents for the school an opportunity for change not only in terms of instruments to manage the teaching/learning process, but above all to reflect on these processes and innovate them in a conscious and critical manner. In pupils media can facilitate the acquisition of awareness of their own mental processes; and allow them to be able to their own learning process; if it well used media, at school, can make choices that are more visible, mental associations, the way to deal with the problematic situations and operating procedures that characterize the mental processes of each student. The most appropriate area to promote the self-regulation of learning in the students is media education, which involves and stimulates complex skills, working both on the development of the mind, emotions and relationships. Media education isn\u2019t implemented in the teaching action of Italian school. However, the digital age and the arrival of new media are revolutionizing the entire communication system, redefining in depth both the tools and the modes of consumption