Vol 516, No 1 (2024)

The structure and phylogeny of the genes StPSY1, StPSY2 and StPSY3, encoding phytoene synthases from Solanum tuberosum L., were characterized. The expression of these genes in potato seedlings was studied in response to exposure to cold stress in the dark phase of the diurnal cycle as an imitation of night cooling. It was found that all three genes are activated when the temperature decreases, and the greatest response is observed for StPSY1. The response of the StPSY3 gene to cold stress and photoperiod has been demonstrated for the first time. A search was carried out for cis-regulatory elements in the promoter region and 5´-UTR of the StPSY genes and it was shown that the regulation of all three genes is associated with the response to light. The high level of low-temperature activation of the StPSY1 gene may be associated with the presence of cis-elements associated with sensitivity to cold and ABA.

The Cuban Macaw, Ara tricolor (Bechstein, 1811), is an extinct species of large parrots with little known historical distribution and ecology. To date, only three late Quaternary paleontological and one archaeozoological (17^th–18^th centuries) finds of the species have been described from central Cuba. This article describes the new (fourth) fossil record of the Cuban Macaw, a fragmentary carpometacarpus from the Upper Pleistocene layers of El Abrón Cave in Pinar del Río province. This is the first documented evidence of the species from the western part of Cuba. The associated fauna indicates that the Cuban Macaw lived in mosaic, semi-open marshy landscapes, probably similar to those in the vicinity of Ciénaga de Zapata in modern times.

The extinct mountain long-eared bat Plecotus macrobullaris sarmaticus subsp. nov. is described on the base of jaw remains from the Lower Pleistocene of the Taurida cave in central Crimea. This is the first record of the genus Plecotus in the Lower Pleistocene of Russia and the first fossil find of P. macrobullaris Kuzyakin, 1965, documenting the early stage of the evolutionary history of the species.

Influenza A virus has a wide natural areal among birds, mammals and humans. One of the main regulatory adaptors of the virus host range is the major NP protein of the viral nucleocapsid. Phylogenetic analysis of the NP protein of different viruses has revealed the existence of two phylogenetic cohorts in human influenza virus population. Cohort I includes classical human viruses that caused epidemics in 1957, 1968, 1977. Cohort II includes the H1N1/2009pdm virus, which had a mixed avian-swine origin, but caused global human pandemic. Also, the highly virulent H5N1 avian influenza virus emerged in 2021 and caused outbreaks of lethal infections in mammals, including humans, appeared to have the NP gene of the second phylogenetic cohort and, therefore, by the type of adaptation to human is similar to the H1N1/2009pdm virus and seems to possess a high epidemic potential for humans. The data obtained shed light on pathways and dynamics of avian influenza viruses adaptation to humans and propose phylogenetic algorithm for systemic monitoring of dangerous virus strains to predict epidemic harbingers and take immediate preventive measures.

The dynamics of the pulse wave (PW) associated with the PW transit time variability (PWTTV) determines the peripheral pulse rate variability, which is used as a surrogate for heart rate variability (HRV). The aim of the work is to analyze the frequency-dependent dynamics of PWTTV and to identify the possible frequency-phase modulation of PW velocity oscillations on the transit from the heart to the soft tissues of the distal parts of the upper extremities. RR-interval recordings and synchronous records of photoplethysmograms of 12 conditionally healthy subjects from the PhysioNet open database were used in this work. Using the Hilbert–Huang transform 3 spectral components of PWTTV and HRV were identified. It was shown that the amplitudes of PWTTV oscillations were many times (up to 8.4 times) smaller than the amplitudes of HRV, and the peaks of PWTTV spectral components were shifted towards higher frequencies than those of HRV. Functional relations between PWTTV and HRV, which can determine the phase modulation of periodic changes in the velocity of propagation of PW, were revealed.

Study of CD4⁺ T-cell response and T-cell receptor (TCR) specificity is crucial for understanding etiology of immune-mediated diseases and developing targeted therapies. However, solubility, accessibility, and stability of synthetic antigenic peptides used in T-cell assays may be a critical point in such studies. Here we present a T-cell activation reporter system using recombinant proteins containing antigenic epitopes fused with bacterial thioredoxin (trx-peptides) and obtained by bacterial expression. We report that co-incubation of CD4⁺ HA1.7 TCR⁺ reporter Jurkat 76 TRP-cells with CD80⁺ HLA-DRB1*01:01⁺ HeLa-cells or CD4⁺ Ob.1A12 TCR⁺ Jurkat 76 TRP with CD80⁺ HLA-DRB1*15:01⁺ HeLa-cells resulted in activation of reporter Jurkat 76 TPR after addition of recombinant trx-peptide fusion proteins, containing TCR-specific epitopes. Trx-peptides were comparable with corresponding synthetic peptides in their capacity to activate Jurkat 76 TPR. These data demonstrate that thioredoxin as a carrier protein (trx) for antigenic peptides exhibits minimal interference with recognition of MHC-specific peptides by TCRs and consequent T-cell activation. Our findings highlight potential feasibility of trx-peptides as a reagent for assessing the immunogenicity of antigenic fragments.