Biological systems and gravity
Fundamental researches in the field of gravitational biology share a common goal – to identify the role of gravity as an evolutionary factor, to understand the nature and mechanisms of its influence on various aspects of life, to reveal the degree of gravity participation in the formation of structural and functional organization of living organisms in the process of their development (phylogenesis and ontogenesis). However, these studies are of practical importance in evaluating risk to living organisms under conditions of prolonged space flight, opportunities, constraints and “cost” of adaptation to the main factors of flight: microgravity and space radiation.
The answer to the question of how and by what mechanisms living organisms react to changes in the magnitude and direction of the gravity vector depends on the decryption and classification of sensors of gravity. The solution to this problem is equally important both in theoretical terms (justification of the role of gravity in the evolution of living systems), and for the successful application of research results in the practice of space biology and medicine (improvement of life support systems, normalization of the human body functions during prolonged space flight and development of new technologies of obtaining of biologically active substances and medicinal products).
Gravity-dependent processes in biological systems of various organization levels (2001-2005) / Гравитационно-зависимые процессы в биологических системах различных уровней организации (2001-2005) (405.3 KiB)
Adaptation of living systems to extreme and gravitational influences, 1 / Адаптация живых систем к экстремальным и гравитационным воздействиям, 1 (1.3 MiB)
The evolution of living systems in the Earth's gravitational field (biomechanical and energy aspects) / Эволюция живых систем в гравитационном поле Земли (биомеханические и энергетические аспекты) (308.6 KiB)
Cell and microgravity
The development of living systems is based on the principle of evolutionary continuity, which is a combination causes a very slow but targeted changes (complications) of primary prokaryotic cell. It is assumed that the most primitive prokaryotic cell (protocell) appeared about 3.5 billion years ago, and only after 2 billion years, a eukaryotic cell appeared. However, the key point in the evolution of the organic world even before the emergence of prokaryotic cells were the process of interaction of structures – carriers of information (macromolecules nucleotides) with catalytic structures, providing the use of energy substrates.
Resulting from the merger the new compounds were already capable of self-assembly and further self-organization into structures of higher order. But self-assembly was just the beginning of a cell and to its final formation required was another step – the isolation (segregation) of this structure from the external (surrounding) environment. For a number of reasons, one of which is to neutralize the effects of gravity, primordial (primitive) single-celled organism could arise and evolve for quite a long time only in the aquatic environment. In fact, immersion environment, among other benefits, allows to greatly weaken the mechanical pressure on the cell, caused by the presence of gravity. In this case, the cell operating in aqueous medium, in order to avoid hydrostatic “stress”, it was enough to produce a well-established mechanism of osmoregulation, which gave her the opportunity not only to maintain the concentration gradients of the main ions K+, Na+, CA++, Mg++, but also to maintain its structural integrity. The main tool and the material basis for realization of the mechanism of cells formation was a biomembrane – the first earliest in evolutionary terms, and important in terms of functionality cell element.
The modern model of the principle of perception and realization of gravitational momentum in the cell are based on the mechanism associated with the transfer of gravitational momentum from the outer membrane into the intracellular continuum, due to the activation of the intracellular signaling system. Due to the physical nature of gravitation, the gravitational stimulus interacts with mass and induces primary mechanical response, expressed in the spatial redistribution of intracellular organelles according to their sizes. In the processes of perception and realization of the gravity impulse can attend almost all the intracellular structures. This primarily refers to the nucleus, largest cellular organelle whose density is 1.5 times higher than the density of the surrounding cytoplasm. However, no less interesting are the variations of quantitative distribution and temporal and spatial localization of such organelles as mitochondria and various types of plastids that have a large size and high density. In the process of interaction, they form short-lived complexes, which from our point of view, can claim the role of unspecialized gravireceptors.
General principles of cellular organization (biophysical and biomechanical aspects) / Общие принципы организации клетки (биофизические и биомеханические аспекты) (472.7 KiB)
Cellular and molecular mechanisms of gravireception, 2 / Клеточные и молекулярные механизмы гравирецепции, 2 (315.5 KiB)
Cell culture in microgravity conditions / - (177.5 KiB)
Cellular and molecular mechanisms of gravireception, 1 / Клеточные и молекулярные механизмы гравирецепции, 1 (315.5 KiB)
The role of gravity in changes of structural and functional state of cells / Роль силы тяжести в изменениях структурно- функционального состояния клетки (386.3 KiB)
Growth and functional regularities of unicellular organisms under altered gravity conditions / - (442.5 KiB)
Structural and functional organization of regenerated plant protoplasts exposed to microgravity on Biokosmos 9 / - (348.9 KiB)
The effect of microgravity on the development of plant protoplasts flown on Biokosmos 9 / - (260.3 KiB)