From Big Medical Encyclopedia

PHOTOBIOLOGY — the section of biology studying the processes proceeding in biological objects under the influence of light (optical) radiation.

Fotobiol. activity light in the visible, ultra-violet and infrared ranges has (see Light, biological effect). Fotobiol. processes are eurysynusic in wildlife. It is possible to distinguish the processes connected with accumulation of solar energy in synthesizable connections from them — photosynthesis (see); the regulatory and information reactions proceeding in organisms under the influence of light — sight (see), a phototaxis (see the Taxis) and phototropism (see Tropisms), photostimulation of growth and development, synthesis of vitamins, pigments and hormones; different destructive processes proceeding in organisms at their radiation by light, etc. (see Fotosensibilization).

Bases F. were put in the middle of 19 century at a research of such fundamental process as photosynthesis. Subsequent development F. it is caused by emergence of quantum representations in physics (see. Quantum biology), development of theoretical and experimental fundamentals of photochemistry (see) and spectroscopy (see), requirements of biology, medical and page - x. practicians. Progress F. it is connected with progress: biochemistry (see), biophysics (see), molecular biology (see), physical and chemical biology (see). And other sciences.

Within F. investigate the most various by the nature and function fotobiol. processes. Studying of the general is of special interest for them stages: initial stages (absorption of quanta of a radiant energy and electronic excitement of molecules of photoreceptors); further stabilization of energy as a result of photochemical reaction (see); educations and transformations of labile photoproducts (free radicals, a radical ion oxidized and got into condition, etc.). Subsequent biochemical reactions and fiziol. the answer at the level of a complex system (a cell, fabric, an organism), are of considerable interest for F. as final result fotobiol. process.

Fotobiol. processes can be divided into two groups corresponding to two directions F.

The first group combines fotobiol. processes, to-rye have adaptive character and sticks and flasks of a retina (see) providing use of light in processes of life activity of cells and an organism proceed in specialized structures, such as chlorolayers (see the Cell). In this group it is possible to allocate a row fotobiol. the processes connected with synthesis of biologically important connections and which are carried out due to energy of the absorbed quanta. The photosynthesis observed at green plants, seaweed and bacteria, which is essentially the only thing biol is most known from them. increase in free energy (see Thermodynamics) since processes of life activity of other organisms are carried out due to the energy accumulated by photosynthesizing organisms happens process, in Krom. To the same group fotobiol. processes sight, a phototaxis and phototropism, and also photoperiodism of plants belongs. They are not connected with accumulation of light energy, and the role them consists in obtaining information, a cut various parameters of light are a source. By means of visual information animals had an opportunity to be guided in a surrounding situation. Plants and animals, using information on character of solar radiation (see), are capable to regulate the growth, formoobrazovatelny processes, a periodic activity rhythm (daily, seasonal) — the so-called phenomenon of photoperiodism. From the same positions it is possible to consider photo-biol. the processes which are the cornerstone such low-investigated, but the important phenomena, as photostimulation and photoregulation of growth, development at the different levels of the organization biol. objects (cell, fabrics, organism).

Second group fotobiol. processes includes the processes leading to damage of structures, disturbance of their functions. Role biol. the organizations here can consist in protection against the damaging action (e.g., synthesis of a pigment of melanin at suntan), reparations of genetic damages (see).

At F-radiation is followed by a denaturation (see) and an inactivation of proteins (enzymes), nucleinic to - t, oxidation of lipids, damage biol. membranes. Bactericidal action of ultraviolet radiation (see), damage of cells and fabrics, an erythema is connected with activation of various biochemical processes (see). Absorption At Physical lucheniye nucleinic to-tami and other connections can be followed by induction of prophases (see L an isogeny), mutagen and oncogenous effects, to serve one of the factors determining the level of mutational variability of nek-ry organisms. Abiogenous synthesis of biologically important connections under action UF-pzlucheny, perhaps, served as premises of emergence of life on Earth (see Life). Ultraviolet, visible and infrared radiation began to be carried to the most important factors of evolution of the biosphere and maintenance of ecological equilibrium (see Theory of evolution).

Recent period of development F. along with profound studying of molecular mechanisms of separate processes it is characterized by a tendency to association of the private directions and creation of the general F., the cut is the purpose clarification of the fundamental principles and mechanisms fotobiol. reactions, ways of their regulation, evolution fotobiol. systems for management fotobiol. processes, creations of artificial photopower, photo information and other systems. To problems F. clarification of the general principles of accumulation of energy belongs, erased at kturno-funktsional-ache also the temporary organization photo-r e c of e n of t a shouting about in (see), r about l and me MB r annas x structures (see Membranes biological) in interface of primary and subsequent stages fotobiol. process, studying of universal mechanisms of protection against the damaging action of radiations, and also development of a problem of a community of processes of various nature (in particular, fotoenergetichesk x, a photo information and photoregulatory), a cut are the cornerstone their evolutionarily arisen interrelations, etc.

For the solution of these problems the extreme importance gets use of the most modern methods: registration sverkhbystry

(10-10 — 10“ 13 sec.) processes, is

use of highly sensitive methods of differential spectroscopy, a luminescent spektrofo-tometriya (see L a yuminestsention, Spekt-rofotometriya), the laser equipment (see the Laser), methods of an electronic paramagnetic resonance (see), nuclear magnetic resonance (see), use of low and cryogenic temperatures, preparative methods of modern molecular biology and biochemistry, etc.

Achievements F. biotechnologies, agriculture, environmental control form a theoretical basis for applied researches in the field of medicine. The medicobiological direction in F. covers a wide range of the problems connected with clarification of features of impact of radiation on cells, fabrics and an organism is normal also at pathology for the purpose of use of results of researches in balneology, dermatology, oncology, and also for fight against pathogenic microorganisms, treatment of diseases of photoreceptor structures of a retina. These researches promote implementation of new methods of treatment, such, e.g., as the laser equipment in surgery, ophthalmology, phototherapy (see Phototherapy).

Researches on F. are conducted in Ying-those biochemistry by it. And. II. Baha of Academy of Sciences of the USSR, Ying-those biophysics of Academy of Sciences of the USSR, Ying-those soil science and photosynthesis of Academy of Sciences of the USSR, Ying-those photobiologies of AN of the Belarusian SSR (Minsk), in Lomonosov Moscow State University, in a number of medical higher education institutions. There is an International committee on photobiology organizing the international congresses according to this section of biology. Bibliography: Konev S. V. and In about l about -

t about in with to and y I. D. Fotobiologiya, Minsk, 1979; To r and with N about in with to and and A. A. Transformation of energy of light at photosynthesis, M., 1974; With m and t To. and X e N e-at about l of t F. Molecular photobiology, the lane with English, M., 1972; GYO to physiology, ed. by A. Page of Giese, v. 1—8, N. Y. — L., 1904 — 1973. F. F. Litvin.