The SPM study of oligonucleotides consisting of repeated nucleotide sequences

The work was performed with financial support of the grant of the Republic of Bashkortostan for the young scientists for 2019, contract № 29GR

Morphometric characteristics of effects induced by <i>Ensifer meliloti</i> lipopolysaccharide fractions on parenchymatous organs in laboratory rats with secondary immunodeficiency

Introduction. Gram-negative bacteria-derived lipopolysaccharides (LPS) are better known as bacterial endotoxins. However, an increasing body of evidence has been accumulated regarding a whole range of LPS-bound physiological effects also observed in normal settings. In particular, LPS derived from some bacterial species was shown to exhibit an immunomodulating activity.Study objective — to characterize physiological effects of Ensifer meliloti lipopolysaccharides in modelled rat induced immunodeficiency.Materials and methods. Biological activity of intraperitoneally administered E. meliloti LPS fractions was studied for 21 days in 60 outbred male rats after induction of a minimal immunodeficiency state 24 hours later after inoculating cytostatic agent cyclophosphamide (CF). Animals were euthanized on day 22 followed by conducting an autopsy and morphometric study of internal organs. Later, paraffin-embedded sections of parenchymal organs were stained with hematoxylin-eosin and examined histologically by light microscopy.Results. It was found that at the end of the experiment cyclophosphamide applied to laboratory animals insignificantly decreased weight of liver and kidney, but not that of heart and spleen (compared to intact animals). In contrast, lung weight was solely significantly increased in immunodeficient rats compared to control. Intraperitoneally administered LPS fractions during secondary immunodeficiency affected weight parameters in the liver and kidney as the most intensively blood supplied organs suggesting its systemic effects. Quantity of follicles with large germinal centers as well as secondary follicles and lymphatic sheath formation in splenic stroma was increased that features activated immune response. Moreover, hepatic lymphoid infiltration in the portal tracts and reversal to normal vascular pattern were found as well. In contrast, LPS and Licopid administered to rats resulted in marked lung hyperplasia of lymphoid tissue containing large germinal centers.Conclusion. The data obtained indicate that E. meliloti-derived LPS fractions administered to rats with secondary immunodeficiency positively affected immunoreactivity

EFFECT OF LIPOPOLYSACCHARIDE OF ESCHERICHIA COLI ON PHAGOCYTE AND METABOLIC ACTIVITY OF MICE BLOOD NEUTROPHILS WITH INDUCED IMMUNE DEFICIENCY

Aim. Experimental evaluation of effect of E. coli LPS fractions on phagocyte and metabolic activity of blood neutrophils of laboratory mice with induced immune deficiency. Materials and methods. Phagocyte activity was evaluated by phagocyte number (PN), phagocyte index (PI) and integral phagocyte index (IPI), intensity of metabolism and energetic processes of enzyme systems - by test of tetrazolium nitro blue (TNB), mean cytochemical coefficient (MCC) in spontaneous and induced tests and stimulation index (SI). Results. LPS-3 substance administration into mice with secondary immune deficiency has resulted in a significantly highest increase of PN (15.8%), IPI (17.7%), TNB-IN (10.3%), cytochemical coefficients MCC-IN (u.) and IS (u.) - 14.8 and 10.9%, respectively, compared with the parameters of immune deficient mice that had received licopid. Conclusion. Some fractions of E. coli M17 polysaccharide have immune stimulating activity

Additive Effect of the Composition of Endophytic Bacteria <i>Bacillus subtilis</i> on Systemic Resistance of Wheat against Greenbug Aphid <i>Schizaphis graminum</i> Due to Lipopeptides

The use of biocontrol agents based on endophytic bacteria against phloem-feeding insects is limited by a lack of knowledge and understanding of the mechanism of action of the endophyte community that makes up the plant microbiome. In this work, the mechanisms of the additive action of endophytic strains B. subtilis 26D and B. subtilis 11VM on the resistance of bread spring wheat against greenbug aphid Schizaphis graminum, was studied. It was shown that B. subtilis 26D secreted lipopeptide surfactin and phytohormones cytokinins, and B. subtilis 11VM produced iturin and auxins into the cultivation medium. Both strains and their lipopeptide-rich fractions showed direct aphicidal activity against greenbug aphid. For the first time, it was shown that B. subtilis 26D and B. subtilis 11VM in the same manner, as well as their lipopeptide-rich fractions, activated the expression of salicylate- and ethylene-dependent PR genes, and influenced plant redox metabolism, which led to an increase in plant endurance against aphids. The composition of endophytic strains B. subtilis 26D + B. subtilis 11VM had an additive effect on plant resistance to aphids due to an increase in the number of endophytic bacterial cells, and, as well as due to the synergistic effect of their mixture of lipopeptides − surfactin + iturin, both on the aphid mortality and on the expression of PR1 and PR3 genes. All these factors can be the reason for the observed increase in the growth of plants affected by aphids under the influence of B. subtilis 26D and B. subtilis 11VM, individually and in composition. The study demonstrates the possibility of creating in the future an artificial composition to enhance plant microbiome with endophytic bacteria, which combines growth-promoting and plant immunity stimulating properties against phloem-feeding insects. This direction is one of the most promising approaches to green pesticide discovery in the future