Influenza della combustione di biomasse sulla composizione del particolato atmosferico

Questo lavoro si è posto l’obiettivo di valutare l’effetto dei processi di combustione della biomassa sulla composizione chimica del particolato atmosferico. Sono state analizzate le polveri totali sospese (TSP) e le sotto-frazioni PM10 e PM2.5. Il sito di campionamento è collocato in un’area suburbana costiera nella provincia di Rimini. L’area di studio è soggetta all’apporto di contaminanti derivanti dalle emissioni del traffico autoveicolare (urbano e della vicina autostrada A14) e di piccole attività industriali, tra cui la più importante è l’inceneritore di rifiuti solidi urbani. Il campionamento è stato effettuato nei mesi marzo-aprile 2011. Durante questo periodo ricorre la tradizionale festa popolare delle “Focheracce” dove si bruciano enormi cataste di legna per salutare l’inverno ed accogliere la primavera. In corrispondenza proprio di questa giornata si registra in atmosfera un forte incremento della concentrazione di polveri accompagnato da una variazione nella loro composizione chimica. Il levoglucosano (LG), marker specifico dei processi di combustione della biomassa, mostra concentrazioni di un ordine più elevato rispetto a tutto il periodo di campionamento. Incrementi si registrano, più in generale, per tutti quei composti direttamente imputabili ai processi di combustione incompleta, come CO, CE ed IPA. Il campionamento in occasione dei fuochi ha inoltre evidenziato maggiori concentrazioni in atmosfera di potassio, magnesio, ammonio, nitrati e carbonati nella frazione TSP-PM10. In conclusione, dai risultati della caratterizzazione chimica nelle diverse frazioni granulometriche delle polveri è possibile affermare che i processi di combustione della biomassa, hanno nell’area di studio un ruolo importante nel determinare il carico complessivo delle PM. La correlazione inversa tra temperatura atmosferica e concentrazione di levoglucosano induce a pensare che il contributo dovuto alla combustione di biomassa sulle PM sia imputabile al riscaldamento domestico.

Evaluation of glycoconjugate antigens as vaccine candidates against group A Streptococcus and human immunodeficiency virus infections

This PhD thesis discusses the rationale for design and use of synthetic oligosaccharides for the development of glycoconjugate vaccines and the role of physicochemical methods in the characterization of these vaccines. The study concerns two infectious diseases that represent a serious problem for the national healthcare programs: human immunodeficiency virus (HIV) and Group A Streptococcus (GAS) infections. Both pathogens possess distinctive carbohydrate structures that have been described as suitable targets for the vaccine design. The Group A Streptococcus cell membrane polysaccharide (GAS-PS) is an attractive vaccine antigen candidate based on its conserved, constant expression pattern and the ability to confer immunoprotection in a relevant mouse model. Analysis of the immunogenic response within at-risk populations suggests an inverse correlation between high anti-GAS-PS antibody titres and GAS infection cases. Recent studies show that a chemically synthesized core polysaccharide-based antigen may represent an antigenic structural determinant of the large polysaccharide. Based on GAS-PS structural analysis, the study evaluates the potential to exploit a synthetic design approach to GAS vaccine development and compares the efficiency of synthetic antigens with the long isolated GAS polysaccharide. Synthetic GAS-PS structural analogues were specifically designed and generated to explore the impact of antigen length and terminal residue composition. For the HIV-1 glycoantigens, the dense glycan shield on the surface of the envelope protein gp120 was chosen as a target. This shield masks conserved protein epitopes and facilitates virus spread via binding to glycan receptors on susceptible host cells. The broadly neutralizing monoclonal antibody 2G12 binds a cluster of high-mannose oligosaccharides on the gp120 subunit of HIV-1 Env protein. This oligomannose epitope has been a subject to the synthetic vaccine development. The cluster nature of the 2G12 epitope suggested that multivalent antigen presentation was important to develop a carbohydrate based vaccine candidate. I describe the development of neoglycoconjugates displaying clustered HIV-1 related oligomannose carbohydrates and their immunogenic properties.

Sorveglianza dell'influenza aviare: studio di un sistema di rilevazione precoce della circolazione virale in popolazioni di volatili selvatici

The emergency of infection by highly pathogenic avian influenza virus (HPAI) subtype H5N1 has focused the attention of the world scientific community, requiring the prompt provision of effective control systems for early detection of the circulation of low pathogenic influenza H5 viruses (LPAI) in populations of wild birds to prevent outbreaks of highly pathogenic (HPAI) in populations of domestic birds with possible transmission to humans. The project stems from the aim to provide, through a preliminary analysis of data obtained from surveillance in Italy and Europe, a preliminary study about the virus detection rates and the development of mathematical models, an objective assessment of the effectiveness of avian influenza surveillance systems in wild bird populations, and to point out guidelines to support the planning process of the sampling activities. The results obtained from the statistical processing quantify the sampling effort in terms of time and sample size required, and simulating different epidemiological scenarios identify active surveillance as the most suitable for endemic LPAI infection monitoring in wild waterfowl, and passive surveillance as the only really effective tool in early detecting HPAI H5N1 circulation in wild populations. Given the lack of relevant information on H5N1 epidemiology, and the actual finantial and logistic constraints, an approach that makes use of statistical tools to evaluate and predict monitoring activities effectiveness proves to be of primary importance to direct decision-making and make the best use of available resources.

In Between : The Gap of quality L'influenza dell'insegnamento di Gurdjieff nel teatro di Peter Brook, Decalan Donnellan e Robert Lepage

Il Lavoro é incentrato sull' influenza dell'insegnamento di G. I Gurdjieff sul teatro del novecento in particolare sul lavoro di Peter Brook, Declan Donnellan e Robert Lepage

Epidemiological and functional characterization of Streptococcus pneumoniae pili

Streptococcus pneumoniae is an important life threatening human pathogen causing agent of invasive diseases such as otitis media, pneumonia, sepsis and meningitis, but is also a common inhabitant of the respiratory tract of children and healthy adults. Likewise most streptococci, S. pneumoniae decorates its surface with adhesive pili, composed of covalently linked subunits and involved in the attachment to epithelial cells and virulence. The pneumococcal pili are encoded by two genomic regions, pilus islet 1 (PI-1), and pilus islet-2 (PI-2), which are present in about 30% and 16% of the pneumococcal strains, respectively. PI-1 exists in three clonally related variants, whereas PI-2 is highly conserved. The presence of the islets does not correlate with the serotype of the strains, but with the genotype (as determined by Multi Locus Sequence Typing). The prevalence of PI-1 and PI-2 positive strains is similar in isolates from invasive disease and carriage. To better dissect a possible association between PIs presence and disease we evaluated the distribution of the two PIs in a panel of 113 acute otitis media (AOM) clinical isolates from Israel. PI-1 was present in 30.1% (N=34) of the isolates tested, and PI-2 in 7% (N=8). We found that 50% of the PI-1 positive isolates belonged to the international clones Spain9V-3 (ST156) and Taiwan19F-14 (ST236), and that PI-2 was not present in the absence of Pl-1. In conclusion, there was no correlation between PIs presence and AOM, and, in general, the observed differences in PIs prevalence are strictly dependent upon regional differences in the distribution of the clones. Finally, in the AOM collection the prevalence of PI-1 was higher among antibiotic resistant isolates, confirming previous indications obtained by the in silico analysis of the MLST database collection. Since the pilus-1 subunits were shown to confer protection in mouse models of infection both in active and passive immunization studies, and were regarded as potential candidates for a new generation of protein-based vaccines, the functional characterization was mainly focused on S. pneumoniae pilus -1 components. The pneumococcal pilus-1 is composed of three subunits, RrgA, RrgB and RrgC, each stabilized by intra-molecular isopeptide bonds and covalently polymerized by means of inter-molecular isopeptide bonds to form an extended fibre. The pilus shaft is a multimeric structure mainly composed by the RrgB backbone subunit. The minor ancillary proteins are located at the tip and at the base of the pilus, where they have been proposed to act as the major adhesin (RrgA) and as the pilus anchor (RrgC), respectively. RrgA is protective in in vivo mouse models, and exists in two variants (clades I and II). Mapping of the sequence variability onto the RrgA structure predicted from X-ray data showed that the diversity was restricted to the “head” of the protein, which contains the putative binding domains, whereas the elongated “stalk” was mostly conserved. To investigate whether this variability could influence the adhesive capacity of RrgA and to map the regions important for binding, two full-length protein variants and three recombinant RrgA portions were tested for adhesion to lung epithelial cells and to purified extracellular matrix (ECM) components. The two RrgA variants displayed similar binding abilities, whereas none of the recombinant fragments adhered at levels comparable to those of the full-length protein, suggesting that proper folding and structural arrangement are crucial to retain protein functionality. Furthermore, the two RrgA variants were shown to be cross-reactive in vitro and cross-protective in vivo in a murine model of passive immunization. Taken together, these data indicate that the region implicated in adhesion and the functional epitopes responsible for the protective ability of RrgA may be conserved and that the considerable level of variation found within the “head” domain of RrgA may have been generated by immunologic pressure without impairing the functional integrity of the pilus.

Influenza del sistema immunogenetico KIR nell'alloreattività Natural Killer nel trapianto di rene

Kidney transplantation is the best treatment option for the restoration of excretory and endocrine kidney function in patients with end-stage renal disease. The success of the transplant is linked to the genetic compatibility between donor and recipient, and upon progress in surgery and immunosuppressive therapy. Numerous studies have established the importance of innate immunity in transplantation tolerance, in particular natural killer (NK) cells represent a population of cells involved in defense against infectious agents and tumor cells. NK cells express on their surface the Killer-cell Immunoglobulin-like Receptors (KIR) which, by recognizing and binding to MHC class I antigens, prevent the killing of autologous cells. In solid organ transplantation context, and in particular the kidney, recent studies show some correlation between the incompatibility KIR / HLA and outcome of transplantation so as to represent an interesting perspective, especially as regards setting of immunosuppressive therapy. The purpose of this study was therefore to assess whether the incompatibility between recipient KIR receptors and HLA class I ligands of the donor could be a useful predictor in order to improve the survival of the transplanted kidney and also to select patients who might benefit of a reduced regimen. One hundred and thirteen renal transplant patients from 1999 to 2005 were enrolled. Genomic DNA was extracted for each of them and their donors and genotyping of HLA A, B, C and 14 KIR genes was carried out. Data analysis was conducted on two case-control studies: one aimed at assessing the outcome of acute rejection and the other to assess the long term transplant outcome. The results showed that two genes, KIR2DS1 and KIR3DS1, are associated with the development of acute rejection (p = 0.02 and p = 0.05, respectively). The presence of the KIR2DS3 gene is associated with a better performance of serum creatinine and glomerular filtration rate (MDRD) over time (4 and 5 years after transplantation, p <0.05), while in the presence of ligand, the serum creatinine and MDRD trend seems to get worse in the long term. The analysis performed on the population, according to whether there was deterioration of renal function or not in the long term, showed that the absence of the KIR2DL1 gene is strongly associated with an increase of 20% of the creatinine value at 5 years, with a relative risk to having a greater creatinine level than the median 5-year equal to 2.7 95% (95% CI: 1.7788 - 2.6631). Finally, the presence of a kidney resulting negative for HLA-A3 / A11, compared to a positive result, in patients with KIR3DL2, showed a relative risk of having a serum creatinine above the median at 5 years after transplantation of 0.6609 (95% CI: 0.4529 -0.9643), suggesting a protective effect given to the absence of this ligand.

La cultura architettonica del periodo normanno e l'influenza bizantina in Sicilia

The arguments of the thesis is the relationship between the Norman domination and the Greek-speaking people living in Sicily and Southern Italy. Particularly the ascendancy of the greek culture on the norman architecture and his role in the construction of the Norman Kingdom.

Analysis of the memory B cell response against glycoconjugate vaccines

The development of vaccines directed against polysaccharide capsules of S. pneumoniae, H. influenzae and N. meningitidis have been of great importance in preventing potentially fatal infections. Bacterial capsular polysaccharides are T-cell-independent antigens that induce specific antibody response characterized by IgM immunoglobulins, with a very low IgG class switched response and lack of capability of inducing a booster response. The inability of pure polysaccharides to induce sustained immune responses has required the development of vaccines containing polysaccharides conjugated to a carrier protein, with the aim to generate T cell help. It is clear that the immunogenicity of glycoconjugate vaccines can vary depending on different factors, e.g. chemical nature of the linked polysaccharide, carrier protein, age of the target population, adjuvant used. The present study analyzes the memory B cell (MBC) response to the polysaccharide and to the carrier protein following vaccination with a glycoconjugate vaccine for the prevention of Group B streptococcus (GBS) infection. Not much is known about the role of adjuvants in the development of immunological memory raised against GBS polysaccharides, as well as about the influence of having a pre-existing immunity against the carrier protein on the B cell response raised against the polysaccharide component of the vaccine. We demonstrate in the mouse model that adjuvants can increase the antibody and memory B cell response to the carrier protein and to the conjugated polysaccharide. We also demonstrate that a pre-existing immunity to the carrier protein favors the development of the antibody and memory B cell response to subsequent vaccinations with a glycoconjugate, even in absence of adjuvants. These data provide a useful insight for a better understanding of the mechanism of action of this class of vaccines and for designing the best vaccine that could result in a productive and long lasting memory response.

Funzioni della subunità θ e del dominio PHP della subunità α nel core catalitico della DNA polimerasi III di Escherichia coli

Il core catalitico della DNA polimerasi III, composto dalle tre subunità α, ε e θ, è il complesso minimo responsabile della replicazione del DNA cromosomiale in Escherichia coli. Nell'oloenzima, α ed ε possiedono rispettivamente un'attività 5'-3' polimerasica ed un'attività 3'-5' esonucleasica, mentre θ non ha funzioni enzimatiche. Il presente studio si è concentrato sulle regioni del core che interagiscono direttamente con ε, ovvero θ (interagente all'estremità N-terminale di ε) e il dominio PHP di α (interagente all'estremità C-terminale di ε), delle quali non è stato sinora identificato il ruolo. Al fine di assegnare loro una funzione sono state seguite tre linee di ricerca parallele. Innanzitutto il ruolo di θ è stato studiato utilizzando approcci ex-vivo ed in vivo. I risultati presentati in questo studio mostrano che θ incrementa significativamente la stabilità della subunità ε, intrinsecamente labile. Durante gli esperimenti condotti è stata anche identificata una nuova forma dimerica di ε. Per quanto la funzione del dimero non sia definita, si è dimostrato che esso è attivamente dissociato da θ, che potrebbe quindi fungere da suo regolatore. Inoltre, è stato ritrovato e caratterizzato il primo fenotipo di θ associato alla crescita. Per quanto concerne il dominio PHP, si è dimostrato che esso possiede un'attività pirofosfatasica utilizzando un nuovo saggio, progettato per seguire le cinetiche di reazione catalizzate da enzimi rilascianti fosfato o pirofosfato. L'idrolisi del pirofosfato catalizzata dal PHP è stata dimostrata in grado di sostenere l'attività polimerasica di α in vitro, il che suggerisce il suo possibile ruolo in vivo durante la replicazione del DNA. Infine, è stata messa a punto una nuova procedura per la coespressione e purificazione del complesso α-ε-θ