Characterization of extracellular polymeric substances in sewage sludge

LAUREA MAGISTRALENel presente lavoro, i contenuti di sostanze polimeriche extracellulari (EPS) nei fanghi e la loro relazione con la disidratabilità sono stati studiati su campioni provenienti da due diversi impianti di depurazione (WWTP). Questi campioni sono stati raccolti dalle rispettive linee di trattamento come fanghi ispessiti e non condizionati. I campioni sono stati dapprima caratterizzati in termini di solido secco e contenuto di solido volatile, solidi totali sospesi e contenuto di solidi sospesi volatili, pH, conducibilità, CST e potenziale zeta. Quindi il contenuto di EPS è stato determinato per cinque campioni di ciascun tipo di fango. Gli EPS sono stati caratterizzati in termini di concentrazioni totali, rapporto tra proteine e carboidrati (P:C) e ripartizione come solubile (S-EPS), loosely bound (LB-EPS) e tightly bound (TB-EPS). Una prima analisi è stata condotta per studiare le correlazioni esistenti tra le caratteristiche tipiche dei fanghi e il contenuto di EPS. Lo studio si è concentrato in particolare sui legami tra EPS e CST normalizzato (nCST), che consiste nel CST diviso per la concentrazione di TSS, e il rapporto P:C che sembra possa essere un indicatore di disidratabilità. Successivamente, sono stati effettuati test di disidratazione meccanica (MD) ed elettro-disidratazione (EDW) su un campione di ciascun impianto. I test MD hanno mostrato efficienze di disidratazione leggermente diverse, coerenti con le rispettive caratteristiche dei due fanghi. Al contrario, EDW ha ottenuto efficienze simili. Per comprendere meglio questo comportamento, le EPS sono state caratterizzate prima e dopo MD ed EDW al fine di essere in grado di osservare come questi processi abbiano influenzato l'EPS nei fanghi. Entrambi i processi di disidratazione hanno comportato un aumento dei contenuti di EPS. Mentre EDW ha mostrato un'influenza comparabile per entrambi i campioni, MD si è comportato in modo diverso sul contenuto di EPS nei due fanghi. EDW ha cambiato la ripartizione tra EPS solubile e legato, evidenziando un trasferimento dal secondo al primo tipo di EPS. L'applicazione di un campo elettrico durante EDW è sembrata avere un impatto particolarmente negativo su LB-EPS e S-EPS, che ha confermato l'idea che questi due siano di particolare importanza nel processo di disidratazione. Non è emersa alcuna chiara tendenza riguardo l'effetto di MD sui contenuti di EPS, dimostrando la necessità di ulteriore ricerca in futuro.In this present work, Extracellular Polymeric Substances (EPS) contents in sludge and their relationship with dewaterability were studied on samples originating from two different wastewater treatments plants (WWTP). These samples were collected from their respective treatment lines as thickened and unconditioned. They were first characterized in terms of dry solid and volatile solid content, total suspended solids and volatile suspended solids content, pH, conductivity, CST and zeta potential. Then EPS contents were determined for five samples of each sludge type. EPS were characterized in terms of total levels, protein to carbohydrate (P:C) ratio and repartition as soluble (S-EPS), loosely bound (LB-EPS) and tightly bound (TB-EPS). A first analysis was led to investigate the existing correlations between typical sludge characteristics and EPS content. The study particularly focused on the links between EPS and normalized CST (nCST) which is CST divided by the TSS concentration, and P:C ratio appeared to stand out as a possible indicator of dewaterability. Afterwards, mechanical dewatering (MD) and electro-dewatering (EDW) tests were carried out on a sample from each plant. MD tests showed slightly different dewatering efficiencies, which was coherent with the respective characteristics of the two sludges. EDW on the contrary achieved similar efficiencies. To possibly better understand this behaviour, EPS were characterized before and after MD and EDW in order to be able to observe how they affected EPS in sludge. Both dewatering processes involved an increase in EPS contents. While EDW displayed comparable influence for both samples, MD behaved differently on EPS content in the two sludges. EDW changed the repartition between soluble and bound EPS, evidencing a transfer from the second to the first kind of EPS. The application of an electric field during EDW seemed to particularly impact LB-EPS and S-EPS, which confirmed the idea that these two are of special importance in the dewatering process. No clear trend appeared regarding the effect of MD on EPS contents, requiring further work in the future

Chromosome 19p13.3 deletion in a child with Peutz-Jeghers syndrome, congenital heart defect, high myopia, learning difficulties and dysmorphic features: Clinical and molecular characterization of a new contiguous gene syndrome

The Peutz-Jeghers syndrome (PJS) is an autosomal-dominant hamartomatous polyposis syndrome characterized by mucocutaneous pigmentation, gastrointestinal polyps and the increased risk of multiple cancers. The causative point mutation in the STK11 gene of most patients accounts for about 30% of the cases of partial and complete gene deletion. This is a report on a girl with PJS features, learning difficulties, dysmorphic features and cardiac malformation, bearing a de novo 1.1 Mb deletion at 19p13.3. This deletion encompasses at least 47 genes, including STK11. This is the first report on 19p13.3 deletion associated with a PJS phenotype, as well as other atypical manifestations, thereby implying a new contiguous gene syndrome

A novel mutation in STK11 gene is associated with Peutz-Jeghers Syndrome in Indian patients

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare multi-organ cancer syndrome and understanding its genetic basis may help comprehend the molecular mechanism of familial cancer. A number of germ line mutations in the STK11 gene, encoding a serine threonine kinase have been reported in these patients. However, STK11 mutations do not explain all PJS cases. An earlier study reported absence of STK11 mutations in two Indian families and suggested another potential locus on 19q13.4 in one of them. METHODS: We sequenced the promoter and the coding region including the splice-site junctions of the STK11 gene in 16 affected members from ten well-characterized Indian PJS families with a positive family history. RESULTS: We did not observe any of the reported mutations in the STK11 gene in the index patients from these families. We identified a novel pathogenic mutation (c.790_793 delTTTG) in the STK11 gene in one index patient (10%) and three members of his family. The mutation resulted in a frame-shift leading to premature termination of the STK11 protein at 286(th )codon, disruption of kinase domain and complete loss of C-terminal regulatory domain. Based on these results, we could offer predictive genetic testing, prenatal diagnosis and genetic counselling to other members of the family. CONCLUSION: Ours is the first study reporting the presence of STK11 mutation in Indian PJS patients. It also suggests that reported mutations in the STK11 gene are not responsible for the disease and novel mutations also do not account for many Indian PJS patients. Large-scale genomic deletions in the STK11 gene or another locus may be associated with the PJS phenotype in India and are worth future investigation

Netrin-1 acts as a survival factor for aggressive neuroblastoma

Neuroblastoma (NB), the most frequent solid tumor of early childhood, is diagnosed as a disseminated disease in >60% of cases, and several lines of evidence support the resistance to apoptosis as a prerequisite for NB progression. We show that autocrine production of netrin-1, a multifunctional laminin-related molecule, conveys a selective advantage in tumor growth and dissemination in aggressive NB, as it blocks the proapoptotic activity of the UNC5H netrin-1 dependence receptors. We show that such netrin-1 up-regulation is a potential marker for poor prognosis in stage 4S and, more generally, in NB stage 4 diagnosed infants. Moreover, we propose that interference with the netrin-1 autocrine loop in malignant neuroblasts could represent an alternative therapeutic strategy, as disruption of this loop triggers in vitro NB cell death and inhibits NB metastasis in avian and mouse models

Repression of osteoblast maturation by ERRalpha accounts for bone loss induced by estrogen deficiency

ERRalpha is an orphan member of the nuclear receptor family, the complete inactivation of which confers resistance to bone loss induced by ageing and estrogen withdrawal to female mice in correlation with increased bone formation in vivo. Furthermore ERRalpha negatively regulates the commitment of mesenchymal cells to the osteoblast lineage ex vivo as well as later steps of osteoblast maturation. We searched to determine whether the activities of ERRalpha on osteoblast maturation are responsible for one or both types of in vivo induced bone loss. To this end we have generated conditional knock out mice in which the receptor is normally present during early osteoblast differentiation but inactivated upon osteoblast maturation. Bone ageing in these animals was similar to that observed for control animals. In contrast conditional ERRalphaKO mice were completely resistant to bone loss induced by ovariectomy. We conclude that the late (maturation), but not early (commitment), negative effects of ERRalpha on the osteoblast lineage contribute to the reduced bone mineral density observed upon estrogen deficiency