Genomic Expansion of Magnetotactic Bacteria Reveals an Early Common Origin of Magnetotaxis with Lineage-specific Evolution

The origin and evolution of magnetoreception, which in diverse prokaryotes and protozoa is known as magnetotaxis and enables these microorganisms to detect Earth’s magnetic field for orientation and navigation, is not well understood in evolutionary biology. The only known prokaryotes capable of sensing the geomagnetic field are magnetotactic bacteria (MTB), motile microorganisms that biomineralize intracellular, membrane-bounded magnetic single-domain crystals of either magnetite (Fe3O4) or greigite (Fe3S4) called magnetosomes. Magnetosomes are responsible for magnetotaxis in MTB. Here we report the first large-scale metagenomic survey of MTB from both northern and southern hemispheres combined with 28 genomes from uncultivated MTB. These genomes expand greatly the coverage of MTB in the Proteobacteria, Nitrospirae, and Omnitrophica phyla, and provide the first genomic evidence of MTB belonging to the Zetaproteobacteria and “Candidatus Lambdaproteobacteria” classes. The gene content and organization of magnetosome gene clusters, which are physically grouped genes that encode proteins for magnetosome biosynthesis and organization, are more conserved within phylogenetically similar groups than between different taxonomic lineages. Moreover, the phylogenies of core magnetosome proteins form monophyletic clades. Together, these results suggest a common ancient origin of iron-based (Fe3O4 and Fe3S4) magnetotaxis in the domain Bacteria that underwent lineage-specific evolution, shedding new light on the origin and evolution of biomineralization and magnetotaxis, and expanding significantly the phylogenomic representation of MTB

Toxicological evaluation of an iron-containing veterinary drug and environmental aspects of its residue disposal

The article highlights the results of a comprehensive study of toxicological safety and environmental risks associated with using the iron-containing veterinary drug “Ferodev” (solution for injection), which contains the active substance - iron in the form of hydroxide-dextran complex. The purpose of the study was to determine the parameters of acute toxicity of the drug under the conditions of its intragastric administration to laboratory animals (male white rats) and to analyze the possible consequences of the drug residues entering the environment. During the experiment, it was established that the drug belongs to class V in terms of toxicity – practically non-toxic substances, and to class IV in terms of the degree of danger. At the same time, considering the potential cumulative effect of iron and auxiliary components of the drug, particularly phenol, indicates environmental risks in improper disposal. The need to comply with regulated methods of handling drug residues that ensure environmental safety and reduce the threat to soil and aquatic ecosystems is substantiated. Special attention was paid to the analysis of pathoanatomical changes in animals depending on the level of the administered dose of the drug. Changes in behavior, functional state of internal organs, and mortality depending on the toxicological load were noted. The results of the study indicate the presence of a dose-dependent reaction of the body, which may be important for determining the safe range of use of the drug. An assessment of current approaches to environmentally safe disposal of pharmacological residues was carried out. The data obtained can be used for further regulatory developments in veterinary medicine and environmental protection. Further research will focus on developing regulated methods for environmentally safe disposal of iron-containing veterinary drugs and studying their cumulative impact on biocenoses

Money as a Polycontextual Value and Means of SelfIdentification of a Modern Person: Traditional vs Virtual

The article examines the axiological psycho-philosophical understanding of the phenomenon of money and its value role in modern society. The traditional and virtual context of the representation of the money phenomenon is considered. Following the ideas of G. Simmel, the authors consider money not only as a purely economic, but also a psycho-philosophical, cultural and social phenomenon. Money appears as a result of cultural development of the world and gradually forms a monetary culture as a space of economic and social interaction of people. Under the influence of the monetary culture of one or another historical period, the character of a person’s economic activity, values and life orientations are formed. Modern money culture is often called financial civilization. Peculiarities of modern monetary culture are studied, its main features and problems are determined in the article. The problem of the peculiarities of the constructive and destructive attitude of the individual towards money is identified; a psycho-philosophical and cultural-identification typology of people is described, which is based on clinical observations and interpreted through the prism of psychoanalytic theory. The concept of money is highlighted from the standpoint of a socialpsychological approach. The theoretical foundations of money’s influence on the decision-making process and human behavior are also revealed

Performance and application of scanning nuclear microprobe at the Institute of Applied Physics of the National Academy of Sciences of Ukraine

The scanning nuclear microprobe of the Institute of Applied Physics of the National Academy of Sciences of Ukraine is an analytical channel based on the compact electrostatic accelerator "Sokol" of the Van de Graaff type with the maximum voltage at the high-voltage terminal of 2 MV and is designed for local non-destructive analysis of samples of various origins with high sensitivity (~1 ppm), as well as for the fabrication of three-dimensional small structures of high quality using proton beam writing. The resolution of the microprobe is about 3 μm with a beam current of I ~ 100 pA and 0.6 μm with I ~1 pA. The maximum scanning raster with a focused beam on the sample surface is 1 × 1 mm2. The microprobe implements the techniques of particle-induced X-ray emission, Rutherford backscattering, and secondary electron microscopy. The article also gives examples of the use of the nuclear microprobe in physical research

Morphological Transformations in the Magnetite Biomineralizing Protein Mms6 in Iron Solutions: A Small-Angle X-ray Scattering Study

Magnetotactic bacteria that produce magnetic nanocrystals of uniform size and well-defined morphologies have inspired the use of biomineralization protein Mms6 to promote formation of uniform magnetic nanocrystals in vitro. Small angle X-ray scattering (SAXS) studies in physiological solutions reveal that Mms6 forms compact globular three-dimensional (3D) micelles (approximately 10 nm in diameter) that are, to a large extent, independent of concentration. In the presence of iron ions in the solutions, the general micellar morphology is preserved, however, with associations among micelles that are induced by iron ions. Compared with Mms6, the m2Mms6 mutant (with the sequence of hydroxyl/carboxyl containing residues in the C-terminal domain shuffled) exhibits subtle morphological changes in the presence of iron ions in solutions. The analysis of the SAXS data is consistent with a hierarchical core–corona micellar structure similar to that found in amphiphilic polymers. The addition of ferric and ferrous iron ions to the protein solution induces morphological changes in the micellar structure by transforming the 3D micelles into objects of reduced dimensionality of 2, with fractal-like characteristics (including Gaussian-chain-like) or, alternatively, platelet-like structures