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Introduction: Bastroviruses were discovered in the Netherlands in 2016 in human stool samples and show partial genetic similarities to astroviruses and hepatitis E viruses. Their association with disease onset has not yet been established., Materials and Methods: Metagenomic sequencing of fecal samples of Nyctalus noctula bats collected in the Russian Federation in 2023 was performed. Two almost complete genomes of bastroviruses were assembled. The zoonotic potential of these viruses was assessed using machine learning methods, their recombination was studied, and phylogenetic trees were constructed., Results: A nearly complete bastrovirus genome was de novo assembled in one of the samples, and it was used to assemble another genome in another sample. The zoonotic potential of the virus from one of these samples was estimated as high. The existence of recombination between structural and non-structural polyproteins was demonstrated., Conclusion: Two bastrovirus genomes were assembled, phylogenetic and recombination analyses were performed, and the zoonotic potential was evaluated.

Next-generation sequencing technologies have revolutionized the field of virology by enabling the reading of complete viral genomes, extensive metagenomic studies, and the identification of novel viral pathogens. Although metagenomic sequencing has the advantage of not requiring specific probes or primers, it faces significant challenges in analyzing data and identifying novel viruses. Traditional bioinformatics tools for sequence identification mainly depend on homology-based strategies, which may not allow the detection of a virus significantly different from known variants due to the extensive genetic diversity and rapid evolution of viruses. In this work, we performed metagenomic analysis of bat feces from different Russian cities and identified a wide range of viral pathogens. We then selected sequences with minimal homology to a known picornavirus and used "Switching Mechanism at the 5' end of RNA Template" technology to obtain a longer genome fragment, allowing for more reliable identification. This study emphasizes the importance of integrating advanced computational methods with experimental strategies for identifying unknown viruses to better understand the viral universe.

Background: Small Ca 2+ -binding protein parvalbumin possesses two strong Ca 2+ /Mg 2+ - binding sites located within two EF-hand domains. Most parvalbumins have no tryptophan residues, while cod protein contains a single tryptophan residue, which fluorescence (spectrum maximum position and fluorescence quantum yield) is highly sensitive to the Ca 2+ association/dissociation., Objective: Intrinsic protein fluorescence of cod parvalbumin can be used for elucidating the mechanism of Ca 2+ binding to this protein. Fluorescence of the single tryptophan residue of cod parvalbumin has been used to monitor Ca 2+ -induced changes in the protein, both in steady-state and kinetic mode., Methods: Steady-state fluorescence spectra of cod parvalbumin were measured using Cary Eclipse spectrofluorimeter. Stopped-flow accessories in combination with a novel high-speed spectrofluorimeter were used for measurements of kinetics of Ca 2+ dissociation from cod parvalbumin after fast mixing of Ca 2+ -loaded protein with a chelator of divalent metal cations ethylenediaminetetraacetic acid (EDTA)., Results: The fluorescent phase plots (fluorescence intensity at a fixed wavelength plotted against a fluorescence intensity at another fixed wavelength), constructed from steady state and kinetical data, shows a break at [Ca 2+ ]/[parvalbumin] ratio close to 1. This means that the transition passes through an intermediate state, which is a protein with one bound calcium ion. These observations indicate that the binding of Ca 2+ to cod parvalbumin is sequential., Conclusion: The results of the present spectral study showed that the binding of Ca 2+ to cod parvalbumin is a sequential process. Calcium dissociation rate constants for the two binding sites of cod parvalbumin evaluated from the kinetic data are k off1 = 1.0 s -1 and k off2 = 1.5 s -1 ., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction: Currently, the basis for molecular diagnostics of most infections is the use of reverse transcription polymerase chain reaction (RT-PCR). Technologies based on reverse transcription isothermal loop amplification (RT-LAMP) can be used as an alternative to RT-PCR for diagnostic purposes. In this study, we compared the RTLAMP and RT-PCR methods in order to analyze both the advantages and disadvantages of the two approaches., Material and Methods: For the study, we used reagent kits based on RT-PCR and RT-LAMP. The biological material obtained by taking swabs from the mucous membrane of the oropharynx and nasopharynx in patients with symptoms of a new coronavirus infection was used., Results: We tested 381 RNA samples of the SARS-CoV-2 virus (Coronaviridae: Coronavirinae: Betacoronavirus; Sarbecovirus) from various patients. The obtained values of the threshold cycle (Ct) for RT-PCR averaged 20.0 ± 3.7 s (1530 ± 300 s), and for RT-LAMP 12.8 ± 3.7 s (550 ± 160 s). Proceeding from the theoretical assumptions, a linear relationship between values obtained in two kits was proposed as a hypothesis; the correlation coefficient was approximately 0.827. At the same time, for samples with a low viral load (VL), the higher Ct values in RT-LAMP did not always correlated with those obtained in RT-PCR., Discussion: We noted a significant gain in time for analysis using RT-LAMP compared to RT-PCR, which can be important in the context of testing a large number of samples. Being easy to use and boasting short turnaround time, RT-LAMP-based test systems can be used for mass screening in order to identify persons with medium and high VLs who pose the greatest threat of the spread of SARS-CoV-2, while RT-PCR-based diagnostic methods are also suitable for estimation of VL and its dynamics in patients with COVID-19.

Purpose: To evaluate the levonorgestrel-releasing intrauterine system Donasert ® (also known as Levosert ® ) compared with the reference product Mirena ® for the alleviation of heavy menstrual bleeding (HMB)., Materials and Methods: A phase 3 multicentre, non-inferiority, active-controlled study in non-menopausal women with HMB (menstrual blood loss [MBL] ≥ 80 mL) as the primary symptom randomised to either Donasert ® or Mirena ® and followed for 6 months. MBL was evaluated using a validated, modified version of the Wyatt pictogram., Results: Overall, 312 were randomised (158 to Donasert ® and 154 to Mirena ® ). The mean (standard deviation) absolute change in MBL from baseline to 6 months in the per-protocol population ( N  = 300) was -130 (71.8) mL and -127 (67.3) mL in the Donasert ® and Mirena ® groups, respectively; non-inferiority of Donasert ® was confirmed ( p -value <0.0001). Successful treatment of HMB (MBL <80 mL) and a decrease to ≤50% of baseline MBL was achieved in 139/154 (90.3%) and 126/146 (86.3%) participants in the Donasert ® and Mirena ® groups, respectively and the between-treatment difference was non-significant. Most adverse events were mild in severity. Only two device expulsions occurred in the study and there were no uterine perforations., Conclusions: Donasert ® has equivalent efficacy and safety during the first 6 months foralleviation of HMB compared to the reference device, Mirena ® ., Trial Registration Number: 348 (Clinical Trials Registry of the Ministry of Health of the Russian Federation, http://grls.rosminzdrav.ru/default.aspx).

Introduction: Since the outbreak of the COVID-19 pandemic caused by SARS-CoV-2 novel coronavirus, the international community has been concerned about the emergence of mutations altering some biological properties of the pathogen like increasing its infectivity or virulence. Particularly, since the end of 2020, several variants of concern have been identified around the world, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2). However, the existing mechanism of detecting important mutations are not always effective enough, since only a relatively small part of all pathogen samples can be examined by whole genome sequencing due to its high cost., Material and Methods: In this study, we have designed special primer panel and used it for targeted highthroughput sequencing of several significant S-gene (spike) regions of SARS-CoV-2. The Illumina platform averaged approximately 50,000 paired-end reads with a length of ≥150 bp per sample. This method was used to examine 579 random samples obtained from COVID-19 patients in Moscow and the Moscow region from February to June 2021., Results: This study demonstrated the dynamics of distribution of several SARS-CoV-2 strains and its some single mutations. It was found that the Delta strain appeared in the region in May 2021, and became prevalent in June, partially displacing other strains., Discussion: The obtained results provide an opportunity to assign the viral samples to one of the strains, including the previously mentioned in time- and cost-effective manner. The approach can be used for standardization of the procedure of searching for mutations in individual regions of the SARS-CoV-2 genome. It allows to get a more detailed data about the epidemiological situation in a region.

Strontium salts are used for treatment of osteoporosis and bone cancer, but their impact on calcium-mediated physiological processes remains obscure. To explore Sr 2+ interference with Ca 2+ binding to proteins of the EF-hand family, we studied Sr 2+ /Ca 2+ interaction with a canonical EF-hand protein, α-parvalbumin (α-PA). Evaluation of the equilibrium metal association constants for the active Ca 2+ binding sites of recombinant human α-PA ('CD' and 'EF' sites) from fluorimetric titration experiments and isothermal titration calorimetry data gave 4 × 10 9 M -1 and 4 × 10 9 M -1 for Ca 2+ , and 2 × 10 7 M -1 and 2 × 10 6 M -1 for Sr 2+ . Inactivation of the EF site by homologous substitution of the Ca 2+ -coordinating Glu in position 12 of the EF-loop by Gln decreased Ca 2+ /Sr 2+ affinity of the protein by an order of magnitude, whereas the analogous inactivation of the CD site induced much deeper suppression of the Ca 2+ /Sr 2+ affinity. These results suggest that Sr 2+ and Ca 2+ bind to CD/EF sites of α-PA and the Ca 2+ /Sr 2+ binding are sequential processes with the CD site being occupied first. Spectrofluorimetric Sr 2+ titration of the Ca 2+ -loaded α-PA revealed presence of secondary Sr 2+ binding site(s) with an apparent equilibrium association constant of 4 × 10 5 M -1 . Fourier-transform infrared spectroscopy data evidence that Ca 2+ /Sr 2+ -loaded forms of α-PA exhibit similar states of their COO - groups. Near-UV circular dichroism (CD) data show that Ca 2+ /Sr 2+ binding to α-PA induce similar changes in symmetry of microenvironment of its Phe residues. Far-UV CD experiments reveal that Ca 2+ /Sr 2+ binding are accompanied by nearly identical changes in secondary structure of α-PA. Meanwhile, scanning calorimetry measurements show markedly lower Sr 2+ -induced increase in stability of tertiary structure of α-PA, compared to the Ca 2+ -induced effect. Theoretical modeling using Density Functional Theory computations with Polarizable Continuum Model calculations confirms that Ca 2+ -binding sites of α-PA are well protected against exchange of Ca 2+ for Sr 2+ regardless of coordination number of Sr 2+ , solvent exposure or rigidity of sites. The latter appears to be a key determinant of the Ca 2+ /Sr 2+ selectivity. Overall, despite lowered affinity of α-PA to Sr 2+ , the latter competes with Ca 2+ for the same EF-hands and induces similar structural rearrangements. The presence of a secondary Sr 2+ binding site(s) could be a factor contributing to Sr 2+ impact on the functional activity of proteins.