Bioremediation of PCB-contaminated marine sediments: From identification of indigenous dehalorespirers to enhancement of microbial reductive dechlorination

Marine sediments are the main accumulation reservoir of organic recalcitrant pollutants such as polychlorinated biphenyls (PCBs). In the anoxic conditions typical of these sediments, anaerobic bacteria of the phylum Chloroflexi are able to attack these compounds in a process called microbial reductive dechlorination. Such activity and members of this phylum were detected in PCB-impacted sediments of the Venice Lagoon. The aim of this work was to investigate microbial reductive dechlorination and design bioremediation approaches for marine sediments of the area. Three out of six sediment cultures from different sampling areas exhibited dechlorination activities in the same conditions of the site and two phylotypes (VLD-1 and VLD-2) were detected and correlated to this metabolism. Biostimulation was tested on enriched dechlorinating sediment cultures from the same site using five different electron donors, of which lactate was the best biostimulating agent; complementation of microbial and chemical dechlorination catalyzed by biogenic zerovalent Pd nanoparticles was not effective due to sulfide poisoning of the catalyst. A new biosurfactant-producing strain of Shewanella frigidimarina was concomitantly obtained from hydrocarbon-degrading marine cultures and selected because of the low toxicity of its product. All these findings were then exploited to develop bioremediation lab-scale tests in shaken reactors and static microcosms on real sediments and water of the Venice lagoon, testing i) a bioaugmentation approach, with a selected enriched sediment culture from the same area, ii) a biostimulation approach with lactate as electron donor, iii) a bioavailability enhancement with the supplementation of the newly-discovered biosurfactant, and iv) all possible combinations of the afore-mentioned approaches. The best bioremediation approach resulted to be a combination of bioaugmentation and bioremediation and it could be a starting point to design bioremediation process for actual marine sediments of the Venice Lagoon area.

Resistance and opposition to the Macedonian kingship in the ancient Iranian world

This thesis deals with the criticism of Macedonian kingship in the ancient Iranian world. The question of indigenous opposition and resistance to the Greeks and Macedonians has been little addressed by ancient historians. The study therefore adopts a different, interdisciplinary perspective and seeks to understand where the utterly negative portrayal of Alexander and the Macedonians found in most Iranian sources stems from. The first part deals with the subject by first examining the acts of violence committed by Alexander and his men against the Iranians during the expedition to Asia that might have led to such a portrayal in the Iranian sources. I have focused on looting, massacres and insults to deities, such as the looting of temples or the destruction of many settlements in ancient Iran handed down in classical sources. To this end, an important part was devoted to the analysis of archaeological sources, especially the signs of destruction in areas such as Persia and Sogdiana. In the second part, the image of Alexander and his successors, although mentioned much less frequently, as it appears in pre-Islamic Iranian literature, is analysed in detail, focusing on the faults and cruelties attributed to them against the Iranians, but especially against their religion. These are mostly Zoroastrian religious sources, whose clergy preserved a demonic image of the Macedonian kings. In the third and final part, further examples of offences committed by the Diadochi and Seleucids against the Iranians in the classical tradition are collected. At the same time, it is examined how the Hellenistic rulers of Iranian origin, e.g. the Arsacids and the Orontids, opposed not only militarily but also ideologically the Macedonian tradition represented by the kingdoms of Macedonian descent and chose a pro-Iranian tradition that was clearly different from the Greco-Roman one.

I “resabios” come sovversione. Etnostoria dei movimenti di indigeni, donne e lavoratori nello «Stato apparente» boliviano

La tesi adotta una prospettiva etnostorica rafforzata da una metodologia etnografica per analizzare lo sviluppo dei processi di politicizzazione nel territorio boliviano dal periodo coloniale ad oggi, collocandoli all’interno di un più ampio sistema di relazioni economiche, politiche e sociali dettate dall’eterogeneo sviluppo del capitalismo globale; la tesi mostra sia il modo specifico in cui, nelle varie contingenze storiche, queste relazioni hanno riorganizzato l’«abigarrada» società boliviana e inciso sui processi di politicizzazione, sia il modo in cui i soggetti hanno contestato e messo in tensione tale riorganizzazione. Per l’analisi si partirà dalla posizione di quei soggetti che sono stati definiti alternativamente come indios, indigeni, campesinos nel territorio boliviano, guardando alle connessioni politiche che questi hanno messo in campo con diversi soggetti – donne, lavoratori, attivisti urbani. Questa posizione offre una «prospettiva epistemologica privilegiata» per indagare il modo in cui i movimenti sociali impattano nell’articolazione tra Stato, società civile e capitale, non perché tali soggetti sono portatori di un’autenticità alternativa al capitalismo, ma perché il modo in cui riattivano quell’insieme di miti, credenze e residui precapitalistici – i «resabios» – che concorrono alla «memoria larga» delle lotte, innestandoli su elementi introdotti dal capitalismo, mostra la loro capacità di sovvertire la posizione subalterna che la riproduzione del capitale nel territorio boliviano ha imposto loro. Si mostreranno anche le tensioni e i conflitti dati dalle diverse posizioni che donne e uomini, giovani e anziani, figure d’autorità e ‘base’ assumono all’interno della loro identificazione come indigeni. La ricerca permette di affermare che l’identità indigena è il prodotto della risposta istituzionale che di volta in volta è stata data per neutralizzare l’emergenza politica di soggetti la cui eterogeneità non ha impedito, ma al contrario ha reso possibile, un’accumulazione di forza tale da mettere in crisi gli assetti politici, economici e istituzionali dello Stato post-coloniale.