SARS-CoV-2 is constantly evolving, leading to new variants. We analysed data from 4400 SARS-CoV-2-positive samples in order to pursue epidemiological variant surveillance and to evaluate their impact ...on public health in Italy in the period of April-December 2021. The main circulating strain (76.2%) was the Delta variant, followed by the Alpha (13.3%), the Omicron (5.3%), and the Gamma variants (2.9%). The B.1.1 lineages, Eta, Beta, Iota, Mu, and Kappa variants, represented around 1% of cases. There were 48.2% of subjects who had not been vaccinated, and they had a lower median age compared to the vaccinated subjects (47 vs. 61 years). An increasing number of infections in the vaccinated subjects were observed over time, with the highest proportion in November (85.2%). The variants correlated with clinical status; the largest proportion of symptomatic patients (59.6%) was observed with the Delta variant, while subjects harbouring the Gamma variant showed the highest proportion of asymptomatic infection (21.6%), albeit also deaths (5.4%). The Omicron variant was only found in the vaccinated subjects, of which 47% had been hospitalised. The diffusivity and pathogenicity associated with the different SARS-CoV-2 variants are likely to have relevant public health implications, both at the national and international levels. Our study provides data on the rapid changes in the epidemiological landscape of the SARS-CoV-2 variants in Italy.
Since the beginning of the pandemic, SARS‐CoV‐2 has shown a great genomic variability, resulting in the continuous emergence of new variants that has made their global monitoring and study a ...priority. This work aimed to study the genomic heterogeneity, the temporal origin, the rate of viral evolution and the population dynamics of the main circulating variants (20E.EU1, Alpha and Delta) in Italy, in August 2020–January 2022 period. For phylogenetic analyses, three datasets were set up, each for a different main lineage/variant circulating in Italy in that time including other Italian and International sequences of the same lineage/variant, available in GISAID sampled in the same times. The international dataset showed 26 (23% Italians, 23% singleton, 54% mixed), 40 (60% mixed, 37.5% Italians, 1 singleton) and 42 (85.7% mixed, 9.5% singleton, 4.8% Italians) clusters with at least one Italian sequence, in 20E.EU1 clade, Alpha and Delta variants, respectively. The estimation of tMRCAs in the Italian clusters (including >70% of genomes from Italy) showed that in all the lineage/variant, the earliest clusters were the largest in size and the most persistent in time and frequently mixed. Isolates from the major Italian Islands tended to segregate in clusters more frequently than those from other part of Italy. The study of infection dynamics showed a positive correlation between the trend in the effective number of infections estimated by BSP model and the Re curves estimated by birth‐death skyline plot. The present work highlighted different evolutionary dynamics of studied lineages with high concordance between epidemiological parameters estimation and phylodynamic trends suggesting that the mechanism of replacement of the SARS‐CoV‐2 variants must be related to a complex of factors involving the transmissibility, as well as the implementation of control measures, and the level of cross‐immunization within the population.
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The antiepileptic drug zonisamide was considered to act as a weak inhibitor of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1) (with a
K
I of 4.3
μM against the cytosolic isozyme ...II). Here we prove that this is not true. Indeed, testing zonisamide in the classical assay conditions of the CO
2 hydrase activity of hCA II, with incubation times of enzyme and inhibitor solution of 15
min, a
K
I of 10.3
μM has been obtained. However, when the incubation between enzyme and inhibitor was prolonged to 1
h, the obtained
K
I was of 35.2
nM, of the same order of magnitude as that of the clinically used sulfonamides/sulfamates acetazolamide, methazolamide, ethoxzolamide and topiramate (
K
Is in the range of 5.4–15.4
nM). The inhibition of the human mitochondrial isozyme hCA V with these compounds has been also tested by means of a dansylamide competition binding assay, which showed zonisamide and topiramate to be effective inhibitors, with
K
Is in the range of 20.6–25.4
nM. The X-ray crystal structure of the adduct of hCA II with zonisamide has also been solved at a resolution of 1.70
Å, showing that the sulfonamide moiety participates in the classical interactions with the Zn(II) ion and the residues Thr199 and Glu106, whereas the benzisoxazole ring is oriented toward the hydrophobic half of the active site, establishing a large number of strong van der Waals interactions (<4.5
Å) with residues Gln92, Val121, Phe131, Leu198, Thr200, Pro202.
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N-1-(4-Sulfamoylphenyl)-
N-4-pentafluorophenyl-thiosemicarbazide was prepared by the reaction of 4-isothiocyanato-benzenesulfonamide with pentafluorophenyl hydrazine, and proved to be ...an effective inhibitor of several isozymes of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), such as CA I, II, and IX. Against the physiologically relevant isozymes hCA II and hCA IX, the compound showed inhibition constants in the range of 15–19
nM, whereas it was less effective as a hCA I inhibitor (
K
I of 78
nM). The high-resolution X-ray crystal structure of its adduct with hCA II showed the inhibitor to bind within the hydrophobic half of the enzyme active site, making extensive and strong van der Waals contacts with amino acid residues Gln92, Val121, Phe131, Leu198, Thr200, Pro202, in addition to the coordination of the sulfonamide nitrogen to the Zn(II) ion of the active site, and participation of the SO
2NH
2 group to a network of hydrogen bonds involving residues Thr199 and Glu106. These results are helpful for the design of better CA II or CA IX inhibitors based on the thioureido-benzenesulfonamide motif, with potential applications as anti-glaucoma or anti-cancer drugs.
