Mario Amati

Equine Infectious Anemia Virus (EIAV), a lentivirus marked by considerable genetic variability, poses significant diagnostic challenges. Existing diagnostic tools encompass the Agar Gel Immunodiffusion Assay (AGID), enzyme-linked immunosorbent assay (ELISA), and Western blotting (WB). ELISA and AGID mainly utilize the p26 capsid protein, often sourced from the Wyoming reference strain. To broaden the range of viral proteins and strains employed in these immunoassays, we previously developed a novel p26/double-strain gp45 indirect ELISA. In this study, we evaluated the performance of this ELISA in comparison to two commercial EIAV ELISAs using Cohen’s Kappa test and Bayesian Latent Class Analysis (BLCA), a statistical method that estimates test performance without requiring a perfect reference standard. A comparison with the official classification of the sera by the Italian Veterinary Service was also performed. A total of 372 serum samples, including 96 that were positives by all three tests, were analyzed. Results from both Cohen’s Kappa test and BLCA, alongside comparison with official classifications, affirm the diagnostic reliability of the two commercial ELISAs and suggest that the novel ELISA, with its enhanced antigenic diversity, could offer an accurate and reliable diagnostic option for EIAV. This novel assay enhances existing commercial ELISAs and has the potential to strengthen routine diagnostic workflows.

Permethylated anigopreissin A (PAA), a fully protected form of the natural anigopreissin A, was found in our previous study to be active against several cancer cells, up to IC50 0.24 μM for HepG2 cells. Herein, a total of thirteen PAA analogues with variations in the number, position of substituents and unsaturation were synthesised starting from a common precursor, and their ability to induce cell growth inhibition was tested. By comparing the antiproliferative effect of the analogues with PAA and with the help of computational studies, we have gained valuable insights into both the biological activity and structure of this natural class of compounds. Indeed, we discovered the importance of the C-3 ring in modulating the biological activity of PAA, as well as the crucial role of the trans configuration of the styryl double bond and the significance of substitutions on the other parts of the molecule.

Three room-temperature metallomesogens based on Zn(II) cations pentacoordinated by different chelating N^N^N terpyridines and two monodentate gallate co-ligands were designed and synthesized. Depending on the terpyridine ligand's tip functionality, the complexes self-assemble into either a 3D hexagonal mesophase or into a columnar hexagonal mesophase. A systematic study between the structure (molecular architecture, arrangement of the molecules and columns, and chains in both types of mesophases) and photophysical properties (emission maxima and yields, lifetimes of the excited states in the mesophase), correlated with investigations of single molecules in solution, was conducted. Remarkably, one complex exhibited a record quantum yield of 95.0% in solution, while in the mesophase, despite quenching due to the radiative deactivation from the ILCT state, still retained a considerable emission yield of ϕ = 20.2%. The polarized emission of an oriented film, determined for the first time in columnar metallomesogens, shows a dichroic emission ratio (I_||/I_⊥) of 1.30. DFT and TDDFT computational studies confirmed the origin of the observed fluorescence anisotropy from the transition dipole moment oriented along the C₂ symmetry axis of the molecule combined with a high level of order in the 3D mesophase.

The new synthesized Pd^II complex cis-[(bipy)Pd(CBT)₂] (bipy = 2,2′-bipyridyl; CBT = m-carborane-1-thiolate anion), which is a potential BNCT (boron neutron capture therapy) agent and of structure elucidated by single-crystal X-ray work, has been studied by infrared (IR) and ultraviolet–visible light (UV–vis) spectra and its properties compared with those of the previously reported and also the structurally characterized analogue trans-[(py)₂Pd(CBT)₂]. This trans species, prepared via a direct method, was previously isolated from a pyridine solution, consequent to the occurring releasing of the external Pd(CBT)₂ moieties of the porphyrazine macrocycle [{Pd(CBT)₂}₄LZn]·xH₂O (L = tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazinato anion), which is an active photosensitizer in photodynamic therapy (PDT) and a potential bimodal PDT/BNCT agent. The UV-vis spectral behavior of both cis and trans species in CHCl₃ solution and in the gas phase has been examined in detail by density functional theory (DFT) and time-dependent density functional theory (TDDFT) studies devoted to explain their distinct behavior observed in the region of 400–500 nm, as determined by the presence in the cis structure of a vicinal arrangement of the two CBT groups, an ensemble of results closely similar to those observed for the macrocycles [{Pd(CBT)₂}₄LM]·xH₂O (M = Mg^II(H₂O), Zn^II, Pd^II). It has also been experimentally proved the tendency of the cis isomer in CHCl₃/pyridine solution to be changed to the respective trans analogue, with conversion occurring in two steps, as interpreted by detailed DFT studies.

Negative ions are not accurately represented in density functional approximations (DFAs) such as (semi-)local density functionals (LDA or GGA or meta-GGA). This is caused by the much too high orbital energies (not negative enough) with these DFAs compared to the exact Kohn-Sham values. Negative ions very often have positive DFA HOMO energies, hence are unstable. These problems do not occur with the exact Kohn-Sham potential, the anion HOMO energy then being equal to minus the electron affinity. It is therefore desirable to develop sufficiently accurate approximations to the exact Kohn-Sham potential. There are further beneficial effects on the orbital shapes and the density of using a good approximation to the the exact KS potential. Notably the unoccupied orbitals are not unduly diffuse, as they are in the Hartree-Fock model, with hybrid functionals, and even with (semi)local density functional approximations (LDFAs). We show that the recently developed B-GLLB-VWN approximation [Gritsenko et al., J. Chem. Phys. 144, 204114 (2016)] to the exact KS potential affords stable negative ions with HOMO orbital energy close to minus the electron affinity.

A novel flexible ligand with methyl substituted pyrimidine rings and thioether spacers has been synthesised and the corresponding 1 : 1 silver(I) adducts have been obtained by interaction with different silver(I) salts AgX (where X = NO₃ ⁻, BF₄ ⁻, ClO₄ ⁻, CH₃SO₃ ⁻, CF₃CO₂ ⁻, and CF₃CF₂CF₂CO₂ ⁻). The X-ray single crystal structure determination of two of the new silver(I) adducts (X = NO₃ ⁻ and CF₃CO₂ ⁻) has proved the formation of coordination polymers with Ag(I) ions almost linearly coordinated to two nitrogen atoms of the pyrimidine rings of the multitopic ligand used. The linear coordination mode shown by the new flexible ligand is induced by the presence of the substituents on the pyrimidine rings, regardless of the type of the AgX salt used in the formation of the respective silver(I) derivatives. This observation represents a neat change in comparison to the already reported series of complexes with unsubstituted (and otherwise identical) ligands, in which dinuclear coordination units have been invariably obtained. Computational investigations have been performed with the aim of explaining such an observed change. A computational comparison of a known dinuclear complex and its related polymeric one has been detailed here and has allowed us to highlight the importance of the introduced substituents in changing the ligand interactions internally to their coordination units and among adjacent units in the solid phases.

Novel silver(I) acylpyrazolonato coordination polymers of formula [Ag(Q^R)]_n (1–3) have been synthesized by interaction of silver nitrate with HQ^R in methanol in the presence of an equivalent quantity of KOH (in general HQ^R = 1-phenyl-3-methyl-4-RC(═O)-5-pyrazolone, in detail HQ^fb, R = -CF₂CF₂CF₃; HQ^cy, R = -cyclo-C₆H₁₁; HQ^be, R = -C(H)═C(CH₃)₂). [Ag(Q^R)]_n react with 2-ethylimidazole (2EtimH), 1-methylimidazole (Meim), and triphenylphosphine (PPh₃), affording the mononuclear Ag(Q^fb)(EtimH) (4), Ag(Q^cy)(Meim)₂ (5), Ag(Q^be)(Meim) (6), and Ag(Q^R)(PPh₃)₂ (7–9). All complexes have been analytically and spectroscopically characterized, and for some of them the X-ray crystal structure has been resolved. In particular, the single crystal molecular structure determination of Ag(Q^fb)(EtimH) and Ag(Q^be)(PPh₃)₂ has confirmed the different coordination modes of the HQ^fb and HQ^be acylpyrazolone ligands, the former being bound to the silver(I) ion in a monodentate fashion while the latter in the O₂-chelating mode. Density functional theory computations suggest new insights about metal–ligand interactions and the observed linkage isomerism. While phosphine-containing complexes Ag(Q^R)(PPh₃)₂ (7–9) seem not to be able to efficiently inhibit the growth of Escherichia coli and Staphylococcus aureus, the polynuclear complexes [Ag(Q^R)]_n (1–3) and the mononuclear Ag(Q^fb)(EtimH) (4), Ag(Q^cy)(Meim)₂ (5), and Ag(Q^be)(Meim) (6) show a high and almost steady in time antibacterial activity, comparable to that of AgNO₃. This activity is likely related to the degree of saturation of the silver center and to the presence of different ancillary ligands in the diverse typologies of complexes.

The porphyrazine ring shows ambivalent behavior, acting either as an electron acceptor or electron donor in NMe₂or NO₂substituted compounds, respectively. Therefore, even this macrocycle mono-substitution provides an unconventional “push–pull” system.