Mercoledì del PRIN n.5: Viviana Scognamiglio – Danilo Milardi

From NANOplastics to bioplastics towards environmental sustainability: a green algae-based approach (NANOgrab)

Dr. Viviana Scognamiglio

In 2018, over 360 million tons of plastic materials were produced and it is projected that the global production of thermoplastics will amount to 445.25 million metric tons in 2025. At the end of their usage, plastic wastes are degraded into smaller particles becoming microplastics (MPs) and nanoplastics (NPs). In aquatic environments, most MPs/NPs come from synthetic microfibers of clothes/textiles shattered in household washing machines, among diverse sources.

Due to their endangering impact on the environment and human health, an effective and controlled management of MPs/NPs is needed to avoid their huge release in the ecosystems. MPs/NPs removal along the wastewater treatment plants (WWTPs) indicates high separation efficiency; however, while MPs are partially removed, NPs totally escapes treatment processes in significant quantities due to their nanodimensions. Thus, further countermeasures are strongly required to upgrade WWTPs to efficiently remove MPs/NPs and prevent their entering into rivers and the oceans.

NANOgrab proposes the development of a novel bioremediation strategy for water treatment to face NP pollution, based on cultures of photosynthetic microorganisms, i.e. microalgae. Compared to bacterial systems, which may be considered as a biological pollutant due to endotoxins and the requirement of a rich carbon source for growth, microalgae are a valid alternative, being photoautotrophic organisms and not containing endotoxins, known to cause reactions in animals with symptoms of high fever, vasodilation, diarrhea, and in extreme cases, fatal shock. Also, microalgal biomass, which should be disposed of as waste, can be exploited to obtain added value compounds.

NANOgrab objectives are:

1. Obtainment of high efficiency microalgal strains that produce enzymes able to digest NPs: microalgae of fresh and marine water sources will be selected for their ability of NP digestion by means of putative enzymes, identified by bioinformatics and functionally/structurally characterized by spectroscopic techniques and biochemical assays. At the same time, model photosynthetic microalgae will be genetically modified for the production of known and identified digestive enzymes selected among different organisms (e.g. bacteria, fungi, animals), with the aim to obtain a synthetic organism with the desired features of NP digestion.
2. Conversion of microalgal biomass into added value products: the microalgal biomass produced within the bioreactor will be exploited for the extraction of biopolymers for the production of added value compounds, e.g. bioplastics for packaging.

Keywords

1. microalgae;
2. micro-nanoplastics;
3. bioremediation;
4. artificial microorganisms

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Modulating confoRmational Equilibria of prion protein and proteaSome to tune protEostasis neTwork (RESET)

Dr. Danilo Milardi

Many apparently unrelated pathologies termed as “protein conformational diseases” (PCDs), including Alzheimer’s (AD), Parkinson (PD) and prion diseases, are characterized by abnormal accumulation of misfolded, toxic proteins. A hallmark of PCDs is the failure of the proteostasis network (PN), a term which stands for the delicate equilibrium regulating protein synthesis, folding, and clearance.

Hence, the proteasome, an enzyme with specific tasks in protein degradation, is increasingly considered as an attractive target for the development of novel approaches to the treatment of PCDs. Proteasome conformational changes induced by specific regulatory particles (RPs) play a crucial role in driving substrate proteolysis by the catalytic core particle (CP). To be degraded, however, proteins must first unfold and diffuse through a narrow pore at the center of the CP attributing, in turn, a key regulatory role to the conformational changes of the substrate.

This project aims to i) unlock the details of CP/RP recognition, deepening our understanding of proteasome functioning, ii) enable novel strategies to impair prion protein pathogenic conversion and characterize its interaction with CP, iii) develop small molecules able to modulate such processes. To address this complex scenario, we will synergistically employ a combination of NMR, molecular modelling, ESI/MALDI mass spectrometry, and biochemical methods. Based on the notion that  distinct Prion protein (PrP) conformations differently affect proteasome assemblies and function, we will first use PrP as an exemplary model to shed light on

Keywords

1. Proteostasis
2. Proteasome
3. Amyloid