Application of a prioritisation scheme for seismic intervention in schools buildings in Italy

A risk management framework has recently been developed to assign priorities for the rehabilitation of school buildings in Italy, and to give timescales within which retrofit or demolition must take place. Since it is not practical to carry out a detailed assessment of the 60,000 Italian state and public schools, the framework is a multiple-level procedure which aims to identify the highest-risk buildings based on filters of increasing detail, and reduces the size of the building inventory at each step. The first risk ranking is based on a strength deficit, which measures the difference between the current design forces defined for the building site and an estimation of the level of seismic resistance which was required at the time of design. The second ranking is based on lateral strength calculations that are already available for a large portion of the Italian masonry building stock, and that are obtained from a survey form that is familiar to Italian engineers. Finally, a simplified displacement-based methodology is used to give a more accurate assessment of seismic risk based on a limited amount of geometrical and material data. The final assessment leads to a capacity ratio and a risk rating, which are used within a transparent procedure to assign priorities for seismic intervention, and timescales within which detailed assessment leading to retrofit or demolition must take place. The first step of the methodology has been applied herein to the school building stock within two Regions in Italy and preliminary results are presented

Photocatalyzed site- and stereoselective functionalization of β-fucosides

The modification of carbohydrates plays a crucial role in drug design and development. However, while functionalization at the anomeric position is widely explored, C-H bond activation still remains underdeveloped. In this context, photocatalysis allows access to traditionally hindered reactivity[1] and hydrogen atom transfer (HAT) reactions pave the way towards the direct editing of the sugar backbone.[2] Here we present the photocatalyzed C-5 functionalization of β-fucosides. This is achieved using decatungstate anion (TBADT) as catalyst: the oxygen centers in its excited state are highly electrophilic[3] and, after deactivation of fucosides’ positions 1-4, they are able to generate an oxygen-stabilized tertiary nucleophilic radical in position 5. A scope of several fucosides was carried out, with different yields according to the nature of the substituent at the anomeric position. The most promising substrates were treated with several vinylic olefins, achieving full regio- and stereoselectivity. To the best of our knowledge, this work represents the first example of direct C-H functionalization at position 5 of monosaccharides. References 1. D.J. Gorelik, S.P. Desai, S. Jdanova, J.A. Turner, M.S. Taylor, Chem Sci 2024, 15, 1204. 2. L. Capaldo, D. Ravelli, M. Fagnoni, Chem. Rev. 2022, 122, 1875. 3. V. De Waele, O. Poizat, M. Fagnoni, A. Bagno, D. Ravelli, ACS Catal. 2016, 6, 7174

Validation of Plasmodium falciparum dUTPase as the target of 5'-tritylated deoxyuridine analogues with anti-malarial activity

BACKGROUND: Malaria remains as a major global problem, being one of the infectious diseases that engender highest mortality across the world. Due to the appearance of resistance and the lack of an effective vaccine, the search of novel anti-malarials is required. Deoxyuridine 5'-triphosphate nucleotido-hydrolase (dUTPase) is responsible for the hydrolysis of dUTP to dUMP within the parasite and has been proposed as an essential step in pyrimidine metabolism by providing dUMP for thymidylate biosynthesis. In this work, efforts to validate dUTPase as a drug target in Plasmodium falciparum are reported. METHODS: To investigate the role of PfdUTPase in cell survival different strategies to generate knockout mutants were used. For validation of PfdUTPase as the intracellular target of four inhibitors of the enzyme, mutants overexpressing PfdUTPase and HsdUTPase were created and the IC50 for each cell line with each compound was determined. The effect of these compounds on dUTP and dTTP levels from P. falciparum was measured using a DNA polymerase assay. Detailed localization studies by indirect immunofluorescence microscopy and live cell imaging were also performed using a cell line overexpressing a Pfdut-GFP fusion protein. RESULTS:Different attempts of disruption of the dut gene of P. falciparum were unsuccessful while a 3' replacement construct could recombine correctly in the locus suggesting that the enzyme is essential. The four 5'-tritylated deoxyuridine analogues described are potent inhibitors of the P. falciparum dUTPase and exhibit antiplasmodial activity. Overexpression of the Plasmodium and human enzymes conferred resistance against selective compounds, providing chemical validation of the target and confirming that indeed dUTPase inhibition is involved in anti-malarial activity. In addition, incubation with these inhibitors was associated with a depletion of the dTTP pool corroborating the central role of dUTPase in dTTP synthesis. PfdUTPase is mainly localized in the cytosol. CONCLUSION: These results strongly confirm the pivotal and essential role of dUTPase in pyrimidine biosynthesis of P. falciparum intraerythrocytic stages

Metabolomics profiling reveals new aspects of dolichol biosynthesis in Plasmodium falciparum

The cis-polyisoprenoid lipids namely polyprenols, dolichols and their derivatives are linear polymers of several isoprene units. In eukaryotes, polyprenols and dolichols are synthesized as a mixture of four or more homologues of different length with one or two predominant species with sizes varying among organisms. Interestingly, co-occurrence of polyprenols and dolichols, i.e. detection of a dolichol along with significant levels of its precursor polyprenol, are unusual in eukaryotic cells. Our metabolomics studies revealed that cis-polyisoprenoids are more diverse in the malaria parasite Plasmodium falciparum than previously postulated as we uncovered active de novo biosynthesis and substantial levels of accumulation of polyprenols and dolichols of 15 to 19 isoprene units. A distinctive polyprenol and dolichol profile both within the intraerythrocytic asexual cycle and between asexual and gametocyte stages was observed suggesting that cis-polyisoprenoid biosynthesis changes throughout parasite’s development. Moreover, we confirmed the presence of an active cis-prenyltransferase (PfCPT) and that dolichol biosynthesis occurs via reduction of the polyprenol to dolichol by an active polyprenol reductase (PfPPRD) in the malaria parasite

How can natural products serve as a viable source of lead compounds for the development of new/novel anti-malarials?

Malaria continues to be an enormous global health challenge, with millions of new infections and deaths reported annually. This is partly due to the development of resistance by the malaria parasite to the majority of established anti-malarial drugs, a situation that continues to hamper attempts at controlling the disease. This has spurred intensive drug discovery endeavours geared towards identifying novel, highly active anti-malarial drugs, and the identification of quality leads from natural sources would greatly augment these efforts. The current reality is that other than compounds that have their foundation in historic natural products, there are no other compounds in drug discovery as part of lead optimization projects and preclinical development or further that have originated from a natural product start-point in recent years. This paper briefly presents both classical as well as some more modern, but underutilized, approaches that have been applied outside the field of malaria, and which could be considered in enhancing the potential of natural products to provide or inspire the development of anti-malarial lead compounds

Fosmidomycin Uptake into Plasmodium and Babesia-Infected Erythrocytes Is Facilitated by Parasite-Induced New Permeability Pathways

., a mouse malaria parasite. and related parasites. Our data provide further evidence that parasite-induced new permeability pathways may be exploited as routes for drug delivery