Том 9
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Item Coinfection of avian pathogenic Escherichia coli and infectious bursal disease virus in broiler chickens(Національний університет "Києво-Могилянська академія", 2026) Nechypurenko, Oleksii; Furtat, Iryna; Dreval, Denis; Avdeeva, LiliyaInfectious bursal disease virus (IBDV) is the main immunosuppressive agent in the poultry industry that stimulates the development of secondary bacterial infection. However, the avian pathogenic E. coli (APEC) could be a primary agent that induces the development of colibacillosis, nevertheless the absence of immunosuppression. The depletion of bursa after viral replication is crucial for starting bacterial dissemination because of devastation of systemic and local humoral immunity. Therefore, the aim of the work was to investigate the correlation between APEC and IBDV infection in broiler chickens. The bursal atrophy was observed from 21 days with further level depletion from 60 to 90% at the final stage of research. Moreover, APEC strains were isolated from birds at 28–42 days which is correlated with chronical immunosuppression. All E. coli isolates showed resistance to beta‑lactams (amoxicillin, amoxiclav), tetracyclines, and trimethoprim, highlighting the risk of multidrug‑resistant strains. There were no resistant strains to colistin and florfenicol. The IBDV strains were detected in the bursa of 21, 28 and 35 broilers with Ct level 22.8; 25.8; and 32.2 points, respectively that indicates decreasing the viral load. Based on partial nucleotide sequences of the VP2 gene, the pathogen was identified as very virulent United Kingdom 2019 strain. However, analysis of the samples from 42-day-old broilers revealed that the nucleotide sequence belonged to the vaccine strain. Therefore, coinfection of APEC and IBDV in broiler chickens enhances immunosuppression, creating conditions for secondary bacterial infections. The susceptibility to colibacillosis correlates with the stage of bursal depletion and may persist even during replication of the vaccine strain of IBDV after primary infection.Item Molecular strategies of viral replication and their impact on the evolution of genomes of cellular organisms(Національний університет "Києво-Могилянська академія", 2026) Hisem, Maksym; Antonyuk, MaksymThe article explores the fundamental role of viruses as generators of genetic variability and driving force of macroevolutionary processes in the biosphere. Molecular biological strategies of virus replication are analyzed within the paradigm of the Baltimore classification, which considers the genome type as а determinant of transcriptional logic and adaptive potential of viral lineages. Attention is focused on enzymatic replication systems – RNA-dependent RNA polymerase (RdRp) and reverse transcriptase (RT), devoid of an error correction mechanism. It is proven that the high frequency of incorporation of noncomplementary nucleotides and structural variability due to template changes lead to the formation of quasispecies – highly dynamic populations of genetically related subvariants, which ensure evolutionary plasticity and survival of the virus under selective pressure. The molecular mechanisms of viral genome integration into host cell chromosomes as а basic pathway of horizontal gene transfer are outlined. Obligate integration of retroviruses mediated by viral integrases with co-optation of cellular proteins for chromatin navigation are considered, as well as the mechanisms of lysogeny of temperate bacteriophages, which determine the genetic plasticity of prokaryotes and their acquisition of new phenotypic traits (in particular, pathogenicity and stress resistance). The phenomenon of the formation of endogenous viral elements (EVE) because of ancient integrations into eukaryotic germline cells, which became а substrate for the emergence of new regulatory sequences, is described. Hypotheses of the origin of viruses are synthesized. The concept of polyphyletic origin is asserted, according to which different viral classes evolved independently from distinct predecessors (plasmids, retrotransposons) through horizontal gene transfer, gene loss, and recombination, which makes it impossible to identify а single common ancestor. The central aspect of the work is the analysis of the consequences of viral-cellular coevolution through the mechanism of molecular exaptation – co-optation of viral genes by host organisms to perform new biological functions. The molecular basis of the formation of morphophysiological structures and immune mechanisms based on integrated viral sequences is presented. Examples are detailed: fusogenic activity of retroviral syncytin proteins during placentation; the origin of the neuronal gene Arc, which provides intercellular communication and synaptic plasticity, from а retrotransposon; the transposon origin of RAGrecombinase enzymes responsible for somatic recombination of gene segments in the vertebrate adaptive immune system; the evolution of the CRISPR-Cas adaptive immune system of bacteria from casposons; the role of endogenous retroviruses in maintaining the pluripotency of embryonic stem cells (HERV-H) and the functioning of their LTR regions as transcriptional enhancers (MER41). It is argued that viruses are а critical architectural element in the formation of genomes and the evolutionary complexity of cellular biological systems.Item Variability of gliadin blocks in hybrid derivatives of Migushova wheat and common wheat(Національний університет "Києво-Могилянська академія", 2026) Plyhun, Viktoriia; Martynenko, Viktoriia; Ternovska, TamaraThe electrophoretic spectra of gliadin components of Triticum miguschоvae Zhir., B1F4 progeny from crossing Migushova wheat (AbAbGGDD) with common wheat varieties Vdala and Panna, winter common wheat varieties T. aestivum L. (AuAuBBDD) Aurora, Vdala, Leleka, Nikonia, Odeska 267, Panna, Selyanka, Tira, were studied. Comparison of the electrophoretic spectra of gliadins of the parent plants that were used to obtain F1 hybrids revealed the presence of differences in some components of the spectrum for both pairs – Migushova wheat x Vdala and Migushova wheat x Panna. For the first crossbreeding combination, 17 components out of 25 were polymorphic for the spectra of the parental plants. For the second crossbreeding combination, 10 out of 27 were polymorphic. In the gliadin spectra of B1F4 grains, a combination of parental components was found, which confirms the hybrid origin of B1F4 grains. In the spectra of F4 grains, polymorphisms that are characteristic for Migushova wheat prevailed. The only exceptions were components 14 and 24, for which the polymorphism “0”, characteristic of the spectrum of the Vdala variety, prevailed. Components 7 and 21 were not present in the spectra of parental plants of both crosses, but they appeared in the electrophoretic spectra of B1F4 descendants. The version of the cross-pollination of hybrids T. miguschovae x T. aestivum had to be rejected due to the complete sterility of such hybrids, known from previous years of work with hybrids of Miguschova wheat and common wheat. That is, components 7 and 21 are the novelty. For hybrids from the crossing of Miguschova wheat with the Panna variety, the tendency of the dominance of the spectrum components characteristic for Miguschova wheat is preserved, although here too there are exceptions: for components 8 and 18, the polymorphism “1” characterizes Panna and it is most often registered in the spectra of grains. In the spectra of hybrids from this cross, the newest components 7 and 21 are also present. Component 21 is found in almost all spectra with rare exceptions. Component 7 is present in the descendants of four out of six F3 hybrids from the crossing of Migushova wheat with Vdala, and among the hybrids with Panna it is present in the spectra of 11 out of 12 F3 hybrids. Other novel components are 26 and 27. They are present in the spectra of B1F4 grains, which originated from a single F3 plant No. 621. It can be assumed that the molecular event that resulted in the appearance of novel components in the gliadin spectrum occurred precisely in this plant. Its F4 descendants can be involved in further studies at the level of nucleotide sequences of gliadin genes to clarify the nature of molecular processes that occur in genomes of hybrid origin and become the source of the emergence of novel traits.