Extracellular membrane vesicles derived from Komagataeibacter oboediens exposed on the International Space Station fuse with artificial eukaryotic membranes in contrast to vesicles of reference bacterium.

Membranous Extracellular Vesicles (EVs) of Gram-negative bacteria are a secretion and delivery system that can disseminate bacterial products and interact with hosts and the environment. EVs of nonpathogenic bacteria deliver their contents by endocytosis into eukaryotic cells, however, no evidence exists for a fusion delivery mechanism. Here, we describe the fusion of exposed to space/Mars-like stressors simulated on the International Space Station vesicles (E-EVs) from Komagataeibacter oboediens to different types of model planar membranes in comparison with the EVs of the ground-based reference strain. The most reliable fusion was achieved with PC:PE:ergosterol or sterol-free PC:PE bilayers. The relative permeability ratio (PK+/PCl-) estimated from the shift of zero current potential according to Goldman-Hodgkin-Katz equation consisted of 4.17 ± 0.48, which coincides with preferential cation selectivity of the EV endogenous channels. The increase in membrane potential from 50 mV to 100 mV induced the fusion of E-EVs with all tested lipid compositions. The fusion of model exosomes with planar bilayer lipid membranes was confirmed by separate step-like increases in its conductance. In contrast, the ground-based reference K. oboediens EVs never induced the fusion event. In our study, we show membrane lipidome perturbations and increased protein aggregation occurred in the exposed samples in the harsh environment when outer membranes of K. oboediens acquired the capability of both homo- and heterotypic fusion possibly by altered membrane fluidity and the pore-forming capability.

[INTERNATIONAL AND LEGAL, REGIONAL AND SPECIALIZED MEDICAL STANDARDS IN THE HEALTH CARE SECTOR: EXPERIENCE OF UKRAINE].

The purpose of the article is to study specific features, problematic issues that arise during standardization in the health care sector, as well as the significance of this process for protecting the health of the population of Ukraine. The materials for identifying the essence of standardization in the health care sector were the legislation of the EU, Ukraine, as well as information from the WHO, the mass media, the caselaw of the European Court of Human Rights, political and legal publicism, analytical materials, reference editions and Internet resources. The methodological basis of the study is a set of general scientific and special legal methods of scientific cognition, the use of which is determined by the purpose, objectives and specific features of the subject matter of scientific inquiry. International, regional and specialized medical standards in the health care sector have been analyzed. The main requirements and standards enshrined in international acts have been highlighted. It has been established that the main objects of standardization in the health care sector are the rights and obligations of the population and medical workers, medical information and reporting, management and organization of health care, personnel, education, medicinal products, medical services, etc. The expediency of developing standards for medical workers practicing telehealth, cosmetology, as well as providing palliative care has been proved.

[THE LEGAL FRAMEWORK FOR THE RESOLUTION OF THE VARIOUS TYPES OF RELATIONSHIPS].

The objective of the article is to study the main organizational and legal problems of carrying out transplantation of organs and anatomical materials in Ukraine. To achieve this objective, the author has formulated the methodological complex, which included both general scientific methods and special methods of cognition. The application of the historical method made it possible to analyze the retrospective of legal provision of transplantation, to find out the errors (shortcomings) and to establish achievements both in theory and in the activities of medical institutions in the field of transplantation. Systemic and functional analysis allowed us to characterize transplantation as the comprehensive system and its components. By using the comparative and legal method, the author has analyzed international legal acts on the organization and conduction of transplantation in order to formulate propositions for the improvement of Ukrainian legislation. The author in the course of the research has highlighted legal problems that lie in the lack of legal regulation of mutual relations in the process of transplantation between donors, recipients and health care professionals. The author has stressed on the need to revise the principles of conducting transplantation in Ukraine, which is necessary to provide an orderly, acceptable structural basis for the procedures of the acquisition and transplantation of human cells, tissues and organs for therapeutic purposes in compliance with ethical principles. The current situation in the health care system directly indicates the fact that prohibitions and control do not save lives of people. It is necessary to stipulate by the law the possibility of realizing human rights under the condition of inadmissibility of the state's monopoly on transplantation surgeries.

Kombucha Multimicrobial Community under Simulated Spaceflight and Martian Conditions.

Kombucha microbial community (KMC) produces a cellulose-based biopolymer of industrial importance and a probiotic beverage. KMC-derived cellulose-based pellicle film is known as a highly adaptive microbial macrocolony-a stratified community of prokaryotes and eukaryotes. In the framework of the multipurpose international astrobiological project "BIOlogy and Mars Experiment (BIOMEX)," which aims to study the vitality of prokaryotic and eukaryotic organisms and the stability of selected biomarkers in low Earth orbit and in a Mars-like environment, a cellulose polymer structural integrity will be assessed as a biomarker and biotechnological nanomaterial. In a preflight assessment program for BIOMEX, the mineralized bacterial cellulose did not exhibit significant changes in the structure under all types of tests. KMC members that inhabit the cellulose-based pellicle exhibited a high survival rate; however, the survival capacity depended on a variety of stressors such as the vacuum of space, a Mars-like atmosphere, UVC radiation, and temperature fluctuations. The critical limiting factor for microbial survival was high-dose UV irradiation. In the tests that simulated a 1-year mission of exposure outside the International Space Station, the core populations of bacteria and yeasts survived and provided protection against UV; however, the microbial density of the populations overall was reduced, which was revealed by implementation of culture-dependent and culture-independent methods. Reduction of microbial richness was also associated with a lower accumulation of chemical elements in the cellulose-based pellicle film, produced by microbiota that survived in the post-test experiments, as compared to untreated cultures that populated the film. Key Words: BIOlogy and Mars Experiment (BIOMEX)-Kombucha multimicrobial community-Biosignature-Biofilm-Bacterial cellulose. Astrobiology 17, 459-469.

The First Space-Related Study of a Kombucha Multimicrobial Cellulose-Forming Community: Preparatory Laboratory Experiments.

Biofilm-forming microbial communities are known as the most robust assemblages that can survive in harsh environments. Biofilm-associated microorganisms display greatly increased resistance to physical and chemical adverse conditions, and they are expected to be the first form of life on Earth or anywhere else. Biological molecules synthesized by biofilm -protected microbiomes may serve as markers of the nucleoprotein life. We offer a new experimental model, a kombucha multimicrobial culture (KMC), to assess a structural integrity of a widespread microbial polymer - cellulose - as a biosignature of bacteria-producers for the multipurpose international project "BIOlogical and Mars Experiment (BIOMEX)", which aims to study the vitality of pro- and eukaryotic organisms and the stability of organic biomolecules in contact with minerals to analyze the detectability of life markers in the context of a planetary background. In this study, we aimed to substantiate the detectability of mineralized cellulose with spectroscopy and to study the KMC macrocolony phenotype stability under adverse conditions (UV, excess of inorganics etc.). Cellulose matrix of the KMC macrocolony has been mineralized in the mineral-water interface under assistance of KMC-members. Effect of bioleached ions on the cellulose matrix has been visible, and the FT-IR spectrum proved changes in cellulose structure. However, the specific cellulose band vibration, confirming the presence of ß(1,4)-linkages between monomers, has not been quenched by secondary minerals formed on the surface of pellicle. The cellulose-based KMC macrocolony phenotype was in a dependence on extracellular matrix components (ionome, viriome, extracellular membrane vesicles), which provided its integrity and rigidness in a certain extent under impact of stressful factors.