The history of biological research institutes in Russia goes back to the end of the 19th century and begins with the bites of rabid dogs. Inspired by success rabies vaccine developed by Pasteur, at the end of the 19th century, the Institute of Experimental Medicine was established in St. Petersburg.
Biophysics in Soviet Russia became for some time the "darling of fate." The Bolsheviks were obsessed with innovation in society and showed a willingness to support new directions in science. Later, the Institute of Physics of the Russian Academy of Sciences grew out of this Institute.
In the Soviet Union, the authorities were interested in conducting scientific research on a "broad front". It was impossible to miss any of the promising directions that could promise military or economic advantages in the future. Until the early 1990s, state support ensured the priority development of molecular biology and biophysics. In 1992, the new authorities sent an unambiguous signal to scientists: the salary of a researcher became less than the living wage. Many biophysicists who did not think about emigrating before had to go to the West.
At first, Russian biophysics suffered little from "economic" emigration. The development of such means of communication as e-mail and the Internet has made it possible to maintain links between scientists and colleagues. Many began to provide assistance to their institutes with reagents and scientific literature, and continued research on “their own” topics. Due to the inability to live on an academic salary, the influx of students into science has decreased. A generational gap has emerged, which now, after 15 years of change, is beginning to have an ever greater effect: the average age of employees in some laboratories of the Academy of Sciences already exceeds 60 years.
Achievements and discoveries
Russian biophysics has not lost its leading positions in a number of areas headed by scientists who were educated in the 60-80s of the twentieth century. Significant discoveries in science were made by these scientists. Thus, as an example, the creation of last years new science - bioinformatics, whose main achievements are related to computer analysis of genomes. The foundations of this science were laid back in the 60s by a young biophysicist Vladimir Tumanyan who first developed computer algorithm for the analysis of nucleic acid sequences.
biophysicist Anatoly Vanin back in the 60s discovered the role of nitric oxide in the regulation of cellular processes. Later it turned out that nitric oxide is of great medical importance. Nitric oxide is the main signaling molecule of the cardiovascular system With. The study of the role of nitric oxide in this system was awarded the Nobel Prize in 1998. On the basis of nitric oxide, the world's most popular drug to increase potency, Viagra, was created.
Many achievements in the field of biophysics are associated with the self-oscillatory mechanism discovered by Soviet scientists. Belousov-Zhabotinsky reaction. This reaction provides an example of self-organization in inanimate nature; it served as the basis for many models of synergetics that are now fashionable. Oleg Mornev from Pushchino recently showed that autowaves propagate according to the laws of optical waves. This discovery sheds light on the physical nature of autowaves, which can also be considered the contribution of biophysicists to physics.
One of the most interesting areas of modern biophysics is the analysis of the binding of small RNAs to messenger RNA encoding proteins. This connection underlies the phenomenon "RNA interference". The discovery of this phenomenon was awarded the Nobel Prize in 2006. The world scientific community has high hopes that this phenomenon will help fight many diseases.
The most important area of molecular biophysics is the study mechanical properties of a single DNA molecule. The development of fine techniques for biophysical and biochemical analysis makes it possible to monitor such properties of the DNA molecule as stiffness, tensile, bending and tensile strength.
The positions of Russian biophysicists in the field of theory are traditionally strong. George Gursky And Alexander Zasedatelev developed theory of binding of biologically active compounds to DNA t. They suggested that the basis of such binding is the phenomenon of "matrix adsorption". Based on this concept, they proposed an original project for the synthesis of low molecular weight compounds. Such compounds can "recognize" certain places on the DNA molecule and regulate the activity of genes.
Alexander Zasedatelev successfully applies its developments to create domestic biochips which allow to diagnose oncological diseases at early stages. Under the direction of Vladimir Poroikov was created complex of computer programs, allowing to predict the biological activity of chemical compounds by their formulas.
Judging by financial performance, the “palm” for the greatest achievements should be given to biophysics Armen Sarvazyan, who created a number of unique developments in the field examination of the human body using ultrasound. These studies are generously funded by the US military department: for example, Sarvazyan owns the discovery of a connection between tissue hydration (the degree of dehydration) and the state of the body.
Worldview upheavals promise discoveries Simon Shnol: he found out influence of space geophysical factors on the course of physical and biochemical reactions. We are talking about the well-known Gaussian law, or the normal distribution of measurement errors. In reality, all ongoing processes have certain "spectral" characteristics due to the anisotropy of space.
The most significant for all people living on our planet may be the research of biophysics Alexey Karnaukhov. His climate models predict that we are facing global cooling followed by warming. The Gulf Stream that warms Northern Europe, will cease to bring heat from the Atlantic due to the fact that the Labrador Current, which is opposite to it, will be desalinated due to the melting of glaciers and an increase in the flow of northern rivers, thanks to which it will become easier and stop “diving” under the Gulf Stream.
Research Roberta Bibilashvili from the Cardiology Center led to significant results in curing a number of diseases that were previously considered incurable. It turned out that timely intervention (injection of the urokinase enzyme into areas of the brain of patients affected by a stroke) can completely remove the consequences of even very severe attacks! Urokinase is an enzyme that is produced by blood cells and blood vessels and is one of the components of the system that prevents the development of thrombosis.
Of the recent achievements of foreign scientists, two can be noted: firstly, a group of American researchers from the University of Michigan, led by S.J. Weiss discovered one of the genes responsible for the "three-dimensional" development of biological tissue, secondly, scientists from Japan have shown that mechanical stresses help to create artificial vessels. Japanese scientists placed stem cells inside a polyurethane tube and forced fluid through the tube under varying pressure. Pulsation parameters and mechanical stress structures were approximately the same as in real human arteries. The result is encouraging - the stem cells "turned" into the cells lining the blood vessels.
One of the most ancient sciences is, of course, biology. People's interest in the processes occurring within themselves and the surrounding beings arose several thousand years before our era.
Observation of animals, plants, natural processes was an important part of people's lives. Over time, a lot of knowledge has accumulated, methods of studying wildlife and the mechanisms that occur in it have been improved and developed. This led to the emergence of many sections that make up a complex science in total.
Biological research in various areas of life makes it possible to obtain new valuable data that are important for understanding the structure of the planet's biomass. Use this knowledge for practical human purposes (space exploration, medicine, agriculture, chemical industry, and so on).
Many discoveries have made it possible to make biological research in the field of internal structure and functioning of all living systems. The molecular composition of organisms, their microstructure has been studied, many genes have been isolated and studied from the genome of humans and animals, plants. The merits of biotechnology, cellular and allow you to get several harvests of plants per season, as well as to breed animal breeds that give more meat, milk and eggs.
The study of microorganisms made it possible to obtain antibiotics and create tens and hundreds of vaccines that allow defeating many diseases, even those that used to take thousands of lives in epidemics of people and animals.
That's why modern science biology is the limitless possibilities of mankind in many branches of science, industry and health preservation.
Classification of biological sciences
One of the very first appeared private sections of the science of biology. Such as botany, zoology, anatomy and taxonomy. Later, disciplines more dependent on technical equipment began to form - microbiology, virology, physiology, and so on.
There are a number of young and progressive sciences that were formed only in the XX-XXI century and play a large role in modern development biology.
There is not one, but several classifications by which biological sciences can be ranked. Their list is quite impressive in all cases, consider one of them.
| Biology | Private sciences | Botany | deals with the study of the external and internal structure, physiological processes, phylogenesis and distribution in nature of all plants existing on the planet (flora) | Includes the following sections:
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| Zoology | deals with the study of the external and internal structure, physiological processes, phylogenesis and distribution in nature of all animals existing on the planet (fauna) | Disciplines included in: Disciplines:
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| Anthropology | a number of disciplines that study the development and formation of a person in a biological and social environment in a complex | Sections: philosophical, judicial, religious, physical, social, cultural, visual. | ||
| Microbiology | studies the smallest living organisms, from bacteria to viruses | Disciplines: virology, bacteriology, medical microbiology, mycology, industrial, technical, agricultural, space microbiology | ||
General Sciences | Systematics | the tasks include developing the basis for the classification of all life on our planet with the aim of strict ordering and identification of any representative of the biomass | ||
| Morphology | description of external signs, internal structure and topography of the organs of all living beings | Sections: plants, animals, microorganisms, fungi | ||
| Physiology | studies the features of the functioning of a particular system, organ or part of the body, the mechanisms of all processes that ensure its vital activity | Plants, animals, human, microorganisms | ||
| Ecology | the science of the relationship of living beings with each other, the environment and man | Geoecology, general, social, industrial | ||
| Genetics | studies the genome of living beings, the mechanisms of heredity and variability of traits under the influence of various conditions, as well as historical changes in the genotype during evolutionary transformations | |||
biogeography | considers the settlement and distribution certain types living beings on the planet | |||
evolutionary doctrine | reveals the mechanisms of the historical development of man and other living systems on the planet. Their origin and development | |||
| Complex sciences that arose at the junction with each other | Biochemistry | studies the processes occurring in the cells of living beings from a chemical point of view | ||
Biotechnology | considers the use of organisms, their products and or parts for human needs | |||
| studies the mechanisms of transmission, storage and use of hereditary information by living beings, as well as the functions and fine structure of proteins, DNA and RNA. | Related sciences: genetic and cell engineering, molecular genetics, bioinformatics, proteomics, genomics | |||
Biophysics | it is a science that studies all possible physical processes occurring in all living organisms, from viruses to humans | Sections of this discipline will be discussed below. |
Thus, we have tried to capture the main diversity that is the biological sciences. This list with the development of technology and methods of study is expanding and replenishing. Therefore, a unified classification of biology does not exist today.
Progressive biosciences and their significance
The youngest, modern and progressive sciences of biology include such as:
- biotechnology;
- molecular biology;
- space biology;
- biophysics;
- biochemistry.
Each of these sciences was formed no earlier than the 20th century, and therefore is rightfully considered young, intensively developing and the most significant for practical human activity.
Let us dwell on such of them as biophysics. This is a science that appeared around 1945 and became an important part of the entire biological system.
What is biophysics?
To answer this question, first of all, it is necessary to point out its close contact with chemistry and biology. In some issues, the boundaries between these sciences are so close that it is difficult to make out which of them is specifically involved and in priority. Therefore, it is worth considering biophysics as a complex science that studies the deep physical and chemical processes occurring in living systems at the level of both molecules, cells, organs, and at the level of the Biosphere as a whole.
Like any other, biophysics is a science that has its own object of study, goals and objectives, as well as worthy and significant results. In addition, this discipline is closely correlated with several new directions.
Objects of study
For biophysics they are biosystems at different organizational levels.
- viruses, unicellular fungi and algae).
- The simplest animals.
- Individual cells and their structural parts (organelles).
- Plants.
- Animals (including humans).
- ecological communities.
That is, biophysics is the study of the living from the point of view of the physical processes occurring in it.
The tasks of science
Initially, the tasks of biophysicists were to prove the existence of physical processes and phenomena in the life of living beings and to study them, finding out their nature and significance.
Modern tasks of this science can be formulated as follows:
- To study the structure of genes and the mechanisms that accompany their transmission and storage, modifications (mutations).
- Consider many aspects of cell biology (the interaction of cells with each other, chromosomal and genetic interactions, and other processes).
- To study polymer molecules (proteins, nucleic acids, polysaccharides) in combination with molecular biology.
- To reveal the influence of cosmogeophysical factors on the course of all physical and chemical processes in living organisms.
- More deeply reveal the mechanisms of photobiology (photosynthesis, photoperiodism, and so on).
- Implement and develop methods of mathematical modeling.
- Apply the results of nanotechnology to the study of living systems.
From this list, it is obvious that biophysics studies a lot of significant and serious problems. modern society, and the results of this science have importance for man and his life.
History of formation
As a science, biophysics was born relatively recently - in 1945, when he published his work "What is life from the point of view of physics." It was he who first noticed and indicated that many laws of physics (thermodynamic, laws of quantum mechanics) take place precisely in the life and work of organisms of living beings.
Thanks to the work of this man, the science of biophysics began its intensive development. However, even earlier, in 1922, an institute of biophysics was created in Russia, headed by P.P. Lazarev. There, the main role is assigned to the study of the nature of excitation in tissues and organs. The result was the identification of the importance of ions in this process.
- Galvani discovers electricity and its significance for living tissues (bioelectricity).
- A. L. Chizhevsky is the father of several disciplines studying the influence of space on the Biosphere, as well as ionization radiation and electrohemodynamics.
- The detailed structure of protein molecules was studied only after the discovery of X-ray diffraction analysis (X-ray diffraction analysis). This was done by Perutz and Kendrew (1962).
- In the same year, the three-dimensional structure of DNA was discovered (Maurice Wilkins).
- Neher and Zakman in 1991 managed to develop a method for local fixation of the electric potential.
Also, a number of other discoveries allowed the science of biophysics to embark on the path of intensive and progressive modernization in development and formation.
Sections of biophysics
There are a number of disciplines that make up this science. Let's consider the most basic of them.
- Biophysics of complex systems - considers all the complex mechanisms of self-regulation of multicellular organisms (systemogenesis, morphogenesis, synergogenesis). Also, this discipline studies the features of the physical component of the processes of ontogenesis and evolutionary development, the levels of organization of organisms.
- Bioacoustics and biophysics of sensory systems - studies the sensory systems of living organisms (vision, hearing, reception, speech, and others), ways of transmitting various signals. Reveals the mechanisms of energy conversion when organisms perceive external influences (irritations).
- Theoretical biophysics - includes a number of subsciences involved in the study of the thermodynamics of biological processes, the construction of mathematical models of the structural parts of organisms. Also considers kinetic processes.
- Molecular biophysics - considers the deep mechanisms of the structural organization and functioning of such biopolymers as DNA, RNA, proteins, polysaccharides. He is engaged in the construction of models and graphic images of these molecules, predicts their behavior and formation in living systems. Also, this discipline builds supramolecular and submolecular systems in order to determine the mechanism of construction and action of biopolymers in living systems.
- Biophysics of the cell. He studies the most important cellular processes: differentiation, division, excitation and biopotentials of the membrane structure. Particular attention is paid to the mechanisms of membrane transport of substances, potential difference, properties and structure of the membrane and its surrounding parts.
- Biophysics of metabolism. The main ones under consideration are solarization and adaptation of organisms to it, hemodynamics, thermoregulation, metabolism, and the influence of ionization rays.
- Applied Biophysics. It consists of several disciplines: bioinformatics, biometrics, biomechanics, the study of evolutionary processes and ontogenesis, pathological (medical) biophysics. The objects of study of applied biophysics are the musculoskeletal system, methods of movement, methods of recognizing people by physical features. special attention deserves medical biophysics. It considers pathological processes in organisms, methods of reconstruction of damaged sections of molecules or structures or their compensation. Gives material for biotechnology. It has great importance in the prevention of the development of diseases, especially of a genetic nature, their elimination and explanation of the mechanisms of action.
- Habitat biophysics - studies the physical effects of both the local habitats of beings and the effects of near and far space entities. Also considers biorhythms, the influence of weather conditions and biofields on creatures. Develops measures to prevent negative impacts
All these disciplines make an enormous contribution to the development of understanding the mechanisms of life of living systems, the influence of the biosphere and various conditions on them.
Modern achievements
Some of the most significant events that relate to the achievements of biophysics can be named:
- revealed the mechanisms of cloning organisms;
- the features of transformations and the role of nitric oxide in living systems have been studied;
- the relationship between small and messenger RNAs has been established, which in the future will make it possible to find a solution to many medical problems (elimination of diseases);
- discovered the physical nature of autowaves;
- thanks to the work of molecular biophysicists, aspects of DNA synthesis and replication have been studied, which led to the possibility of creating a number of new drugs for serious and complex diseases;
- computer models of all reactions accompanying the process of photosynthesis have been created;
- methods of ultrasonic research of an organism are developed;
- the connection between cosmogeophysical and biochemical processes has been established;
- predicted climate change on the planet;
- discovery of the significance of the enzyme urokenase in the prevention of thrombosis and the elimination of consequences after strokes;
- also made a number of discoveries on the structure of the protein, the circulatory system and other parts of the body.
Institute of Biophysics in Russia
In our country, they exist. M. V. Lomonosov. Based on this educational institution Faculty of Biophysics operates. It is he who trains qualified specialists for work in this area.
It is very important to give a good start to future professionals. They have a tough job ahead of them. A biophysicist is obliged to understand all the intricacies of the processes occurring in living beings. In addition, students must understand physics. After all, this is a complex science - biophysics. Lectures are structured in such a way as to cover all the disciplines related to and constituting biophysics, and cover consideration of both biological and physical issues.
Biophysics (BF), as an independent scientific discipline. Subject and tasks.
Biophysics- this is n., studied physical and physico-chemical. pr-sy flowing into the biosis. on different levels org-tion and is the basis of physiologist-their acts. The emergence of BF is a progress in physics, mathematics, chemistry and biology contributed. bf- from the lecture - this is physical chemistry; This is a chemical physics biologist. systems. The first attempts to explain the biologist. pr-owls are associated with methods of comparison with physical. pr-mi. For example: mm of nerve conduction - as a distribution. waves of oxidation in copper wire in acid.
Living organisms
Points of view: 1) evolutionists (reductionists): all bio percent. can be reduced to the laws of physics and chemistry; 2) anti-evolution. (anti-reduction): cannot be reduced.
Phys. methods are quite crude and lead to the destruction of the biosystem. (eg: electric shock) => penetration through chemicals is necessary.
Methods: 1) Microelectronic. For study. bioelectric potential. Principle: select. object (squid axon). 2) Biomembranes modeling method. Use artificial membranes: a) liposomes, b) bilayer biomembranes, c) proteoliposome. Stud. the process of transport and St-va biomembranes. 3) optical methods, X-ray diffraction analysis using synchrotron radiation, NMR and EPR spectroscopy, 7-resonance spectroscopy, various electrometric methods, microelectrode technology, chemiluminescence methods, laser spectroscopy, the method of tagged atoms, etc. This is Spanish. for medical diagnostics and therapy.
BF tasks (problems):
1. study of issues related to the emergence, exchange, transmission of E in living systems.
2. research. the role of microscopic units, physical-chemical. structures in the functioning of biosystems.
3. ascend. and conduction of nerves. impulses.
5. the effect of ionizing radiation (on m-ly, organs, organisms).
7. problem of permeability class. and fabrics.
8. study biologist. membranes: the nature of the molecules. membranes; arose. potential.
9. study high-molecular compounds with t.zr. physics.
10. study m-mov storage and transmission nasl. info.
11. autonomy.
Sections of biophysics:
1. Molecular - study. structure and physical-chemical properties, biophysics of molecules.
2. BF cells - studied. features of the structure and function of cells and tissue systems.
3. BF of complex systems - study. kinetics of bioprocesses, behavior in time of various processes inherent in living matter and TD biosystems.
Story: 1892- started looking at the bio. from the point of view of physics. A breakthrough at the end of the 30s was the first institute of the BF in the USSR (radiant E and biosystems, generation and conduction of impulses, bioelectricity). 1953 - Department of BF at Moscow State University. 1974 - Department of BF at BSU.
Biological and physical processes and patterns in living systems. Reductionism and anti-reductionism. The principle of qualitative irreducibility.
Living organisms- an open, self-regulating, self-reproducing and developing heterogeneous system, the most important functional substances in which are biopolymers: proteins and nuclei. to-you complex atomic-molecular structure.
The first attempts to explain the biologist. pr-owls are associated with methods of comparison with physical. pr-mi. For example: mm of nerve conduction - as a distribution. waves of oxidation in copper wire in acid; muscle contraction was explained by the work of piezo elements; cell growth. Initially, physics penetrated chemistry - the need to explain how dec. compounds interact in the body - physical chemistry and chemical physics.
Existing 2 camps modern. physics:
1) Reductionists: Any bio process originated. in a living organism can be reduced to a sum of chemical, physical. and mechanical processes. The explanation of the complex c / c is simpler, the incomprehensible c / c is known. Knowing St. Islands of individual elements, comp. system and features of their interaction, you can derive all the properties of this system. arr. more difficult level is the result of the complication of simpler ones. Sometimes: attempts to replace research real object its simplified model. Achievement: Predicting the existence of the planet Neptune. But as a method of thinking is not universal. Failure in biology: they cannot explain from this point of view. life phenomenon.
2) Anti-reductionists: The principle of qualitative irreducibility or bioantired., i.e. the impossibility of reducing the laws and principles that govern living matter to an elementary sum of physico-chemical and mech. processes life process. Those. physico-math. models can not. adequate, if they do not contain elements of the functional organization of living systems. Those. there is a limit after which physical representations cease to be a self-sufficient means of cognition, and then some bio-truths become the determining factor, without which one can no longer do.
The main directions of development of modern biophysics. Levels of biophysical research.
Biophysics- this is n., studied physical and physico-chemical. pr-sy flowing into the biosis. at different levels of org-tion and is the basis of physiology-their acts.
Sections of biophysics: (and the levels are the same... probably))))
1. Molecular - study. structure and physical-chemical properties, biophysics of molecules, biopolymers and suprapillary systems.
2. BF cells - studied. features of the structure and function of cells and tissue systems. BF of membrane processes - Holy Islands of bio-membranes and their parts; BF photobiol. processes - the impact of external light sources on living systems; Radiation BF: effects of ionizing radiation on the body.
3. BF of complex systems - study. kinetics of bioprocesses, behavior in time of various processes inherent in living matter and TD of biosystems - transformations of E in living structures.
Modern BF is rapidly developing, its achievements contribute to the transition of biology to a qualitatively higher level. molecular level research.
I don’t know what else, from Wikipedia, it’s possible as directions: mathematical BF. Applied BF: bioinformatics (although not a separate section of the BF, but very closely related to it); biometrics; biomechanics (functions and structure of the musculoskeletal system and physical movement of biosystems); BF of evolutionary processes; medical BF; ecological BF.
Bio objects are very complex and many factors influence the processes occurring in them. depend on each other. Physics allows you to create simplified models of an object, a cat. are described by the laws of TD, electrodynamics, quantum and classical mechanics. With help physical correlations. data with biol-mi, you can get a deeper understanding of the processes in the bio object. To obtain information in biological systems, various optical methods are used, X-ray structural analysis using synchrotron radiation, NMR and EPR spectroscopy, 7-resonance spectroscopy, various electrometric methods, microelectrode technology, chemiluminescence methods, laser spectroscopy, the method of labeled atoms, etc. This is Spanish. for medical diagnostics and therapy.
4. Thermodynamics as the core of modern biophysics. Subject and tasks. Practical value TD in BF studies.
TD- this is n. about the transformation of E. TD is n., studied. the most general patterns of transformation of various types of E in the system.
TD subject: E; the emergence of E in living systems; interaction alive. syst. from the surrounding environment. Approaches: phenomenological and detailed. TD parameters have value only in the initial and final state.
Methods: statistical (but does not give an idea of the process).
Directions: 1) study. and the calculation of E at rest and when doing work. Study and determine the efficiency of various biol processes. 2) study. dynamic processes in living systems. (transport in-va).
Meaning: Allows you to evaluate the energy changes, prosh. as a result of biochem. p-tions; calculate E of breaking specific chemical bonds; calculate inspection. pressure on both sides of the semipermeables. membranes; calculate the effect of salt concentration in the solution on the solubility of macro-l. Used to describe processes, origin. in electrochem. cells. It is used to substantiate the theory of the origin and evolution of life on Earth.
Subject: the study of balance changes in the system of a living organism - the environment.
Allocate 2 main. directions of use of thermodynamics:
a) calculation of E transformations in a living organ-me and in separate org systems both at rest and when doing work. Determination of the efficiency of biol processes.
b) The study of living organisms as open t\d systems.
Thermodynamics of biological processes
1. Approaches: phenomenological and detailed. The t/d parameters have meaning only in the initial and final states. Thermodynamics is a science that studies the most general patterns of transformation of various types of energy in a system.
2. Practical significance of t/d in biology. Allows you to evaluate the energy changes that occur as a result of biochemical reactions; calculate the breaking energy of specific chemical bonds; calculate the osmotic pressure on both sides of a semipermeable membrane; calculate the effect of salt concentration in solution on the solubility of macromolecules. It is used to describe the processes occurring in electrochemical cells. Involved to substantiate the theory of the origin and evolution of life on Earth
BIOPHYSICS- a science that studies physical properties and phenomena both in the whole organism and in individual organs, tissues, cells, as well as physical and chemical. fundamentals of life processes.
During the development of B. as a science, two sections were distinguished in it, each of which is distinguished by its methodological orientation.
The first section (physical direction, or actually biological physics) studies the physics and physical properties of the organism as a whole or its individual components. This section of biology deals with general problems of the physical thermodynamics of proteins and their transformations, heat and mass transfer, the physics of muscle contraction, and the physical properties of contractile proteins, etc. Biological systems are studied primarily as physical systems, and physical and mathematical modeling is used; mathematical biophysics adjoins here.
The second section of B., which has a predominantly biological orientation, studies the physical and chemical. fundamentals of life processes. Historically, it arose on the basis of physical chemistry and includes the study of particular issues of thermodynamics, kinetics and catalysis of biological processes; fiz.-chem. fundamentals of electrical phenomena in a living cell; physical chemistry of the colloidal state of protoplasm, etc. This section of B. can be conditionally identified with biophysical chemistry (see); it is closely connected with organic chemistry and biochemistry, physiology, pathophysiology and other medical - biol, sciences.
On the basis of B.'s achievements and in connection with the demands of practical medicine, a number of new disciplines related to B. arose: medical physics (see) and radiobiology (see), which are based on a number of fundamental research in the field of interaction of atomic, electromagnetic and corpuscular radiation with living things.
B. distinguishes a complex of information from its various departments, which have found application in medicine under the conditional name "medical biophysics". This includes the study of the effects of radiation based on the analysis of physical. mechanisms of primary reactions that occur in the cell under the action of irradiation. To the area of honey. biophysics is the study of fiz.-chem. properties of individual substances and compounds in the cell and their changes in normal and pathological conditions, as well as the study of the influence on the body of such factors as vibration (see), acceleration (see), weightlessness (see), etc.
The rapid development of B. in the middle of the 20th century. largely contributed to the development of nuclear energy, astronautics and other areas of human activity, which required the development of ways to protect the human body from the effects of ionizing radiation, vibration, acceleration and other physical. factors.
Both directions of B. named above are presented by the corresponding departments on physical. faculties of universities and technical universities, on the one hand, and biol, faculties of universities, medical and veterinary universities - on the other, having different programs and profiles of trained specialists and great differences in their scientific focus.
Methods of biophysics are widely used in theoretical and practical medicine, they give the chance to receive information on physical. processes directly underlying the occurrence of pathological processes. Biophysics has left a big imprint on the doctrine of pathology, on theoretical ideas about inflammation, edema, nephritis, mechanisms of water balance, membrane permeability of cells and their disorders in pathology, etc.
Biophys. methods study the therapeutic effect of the action of various physical. factors used in physiotherapy. Closely connected with B. electrophysiology and neurology, using biophys. ideas about the nature of excitation and conduction in the nerves in the norm or in the interpretation of some pathological manifestations. In ophthalmology, B.'s achievements in the field of photochemical processes occurring in the visual organs are widely used. B. plays an important role in understanding the primary mechanisms of radiation injury and the development of preventive measures for its treatment.
B. is organically connected with pharmacology and toxicology, since it helps to understand the physical and chemical. mechanisms of action of various medicinal substances (drugs, poisons), as well as quantitative indicators of their toxic effects. B. is closely related to immunology and virology (B.'s methods, in particular, play an important role in revealing the nature of viruses and phages).
In honey. In practice, other biophysical methods are also used (electrodiagnostics, colloid-chemical reactions, methods for assessing the physical and chemical properties of erythrocytes, spectral methods, electrical conductivity methods, etc.).
"Physical" B. is less related to medicine, because for a long time it was purely theoretical and had practical significance only in radiation dosimetry. In a crust, time of communication of this direction of B. with medicine expand, through molecular biology it entered the field of molecular pathology when diseases are connected with disturbances in a structure of large biopolymeric molecules, for example, hemoglobin, etc.
History of biophysics
Purely formally, attempts to apply the laws of physics to biology can be attributed to the moment of the emergence of physics. However, such attempts were naive from the point of view of their application and were clearly mechanistic in nature, since external analogies played the main role in them - biol, phenomena that outwardly resemble physical ones were interpreted as physical. manifestations. So, for example, in the middle of the 19th century. as a model for explaining the mechanism of muscle contraction, the piezoelectric effect was proposed (the phenomenon of a change in the volume of crystals under the influence of electric field), on the principle of which a model was constructed - rubber films, laid with metal plates, contracting under the influence of an electric field. At the same time, attempts to apply the laws of physics and mechanics had a positive outcome. So, J. Borelli explained by the laws of mechanics all forms of animal movement, including muscle contraction and digestion. W. Harvey, on the basis of quantitative measurements and the application of the laws of hydraulics, created the doctrine of blood circulation. A stage in B.'s development was L. Galvani's research (the discovery of animal electricity in 1791), which ultimately led to the creation of electrophysiology (see), and also aroused interest in studying the mechanism of the origin of bioelectric potentials and their significance in fiziol, processes ( see Bioelectric potentials). The first attempt to explain the mechanism of the emergence of bioelectric potentials is associated with the name of E. Dubois-Reymond (mid-19th century). He showed the connection of excitation with the development of electrical activity. The direct development of Dubois-Reymond's views was the idea of membranes as interfaces on which the formation of an electric charge occurs, the author of which was J. Bernstein. The discovery of the first law of thermodynamics - the connection between work and heat - served as a powerful impetus for the development of bioenergetics (see). A large role in the formation of B. belongs to the German physiologist and physicist G. Helmholtz. He gave a description of the eye as an optical system, described the operation of an acoustic apparatus from a physical point of view, and for the first time measured the speed of propagation of nervous excitation. Being one of the founders of thermodynamics, Helmholtz was the first to make an attempt to apply the second law of thermodynamics to living organisms.
A major event for its time was the appearance of the cable theory of excitation and conduction. electrical impulse(beginning of the 20th century), based on the discovery of a high electrical resistance of the nerve sheath and a relatively high electrical conductivity of the core (see Excitation). The physical model of this phenomenon was an electric cable with a metal core and an outer sheath - an insulator. This theory contributed to the development of ideas about the electrical properties of the nervous tissue. Of great interest was the model of nervous excitation proposed by R. Lillie, who showed that if a metal wire is placed in a solution of strong acid and its surface (oxide) layer is mechanically damaged, then potentials arise in this system that, in their characteristics, resemble electrical phenomena , which arise when the spread of excitation along the nerves. This model was subjected to detailed analysis, widely discussed in the literature, and stimulated further research into the electrical properties of the nervous tissue.
With the appearance in physics of quantum-mechanical ideas about the nature of radiation (20s), a theory arose [D. Lee, Altman (W. I. Altman), H. V. Timofeev-Resovsky and others], who tried to explain the laws of the action of radiation on organisms from quantum positions, the so-called. target and hit theory. This theory explained the action of various types of radiation (ultraviolet, x-ray, and nuclear) by the probability of active particles entering the so-called. hypothetical sensitive volume. This theory, although it did not achieve its main goal in explaining the mechanism of radiation injury, however, played a large role in revealing the quantitative relationships between the dose and energy absorbed by the object, as well as in the development of some theoretical issues of genetics and, in particular, the theory of the gene.
The emergence of biophys. Chemistry (chemical biophysics, or physical-chemical biology) is closely related to physical chemistry, which arose from the need to generalize the links between physical. properties of molecules and their chem. activity. The successes achieved by various branches of physical chemistry (electrochemistry, colloid chemistry, kinetics of chem. reactions, thermodynamics, etc.), showed that many mechanisms biol, the phenomena can be understood with fiz.-chem. points of view.
IM Sechenov, using the methods of physical chemistry and mathematical analysis, studied the dynamics of the respiratory process and at the same time established the quantitative laws of the solubility of gases in biol, liquids. He also suggested calling the field of this kind of research molecular physiology.
Great influence on the development of biophys. research was provided by the theory of electrolytic dissociation of S. Arrhenius (1887). He showed that fiz.-chem. the activity of salts is associated with the appearance of charged ions. Immediately there was an assumption that biol, the role of salts is associated with their dissociation into ions, and on the basis of this theory, the Kiev physiologist 13. Yu. Chagovets built an original theory of excitation - the so-called. the capacitor theory of excitation, which quickly gained worldwide popularity. At the same time, an idea arose of cell membranes as a substrate, on which ions form electrically charged layers, thus creating a resting potential.
Developing this idea from a quantitative standpoint, W. Nernst (1899) created a quantitative theory of excitation and derived a law that makes it possible to calculate excitation thresholds depending on the exposure time during electrical stimulation. This law makes it possible to explain the change in the excitability threshold depending on the frequency of the alternating current and to calculate in advance the possibility of using high-frequency sources of electric current for deep heating of body tissues (diathermy).
The theory of ionic excitation was developed by P.P. Lazarev, who introduced the concept of the existence of a threshold critical point of coagulation of cellular proteins responsible for the occurrence of excitation. In the 20s of the 20th century. this theory was finally formulated by him. In a present time, it appears in the literature as the Nernst-Lazarev excitation theory.
In 1910, R. Geber showed that the electrical conductivity of erythrocytes depends on the frequency of the alternating current. Using high-frequency currents, R. Geber found that at frequencies of the order of a megahertz, the electrical conductivity of erythrocytes is several tens of times higher than the electrical conductivity at sound frequencies, and corresponds to the electrical conductivity of a 0.1 M potassium chloride solution. It was found that the change in electrical conductivity depending on the frequency of the applied electric current is characteristic of living cells, and the value of the ratio of low-frequency resistance to high-frequency resistance can be used to assess cell viability. It turned out to be possible by this criterion to clearly determine the moment of cell death under the influence of low temperatures, toxic substances, etc. The electrical conductivity method began to be used in assessing the viability of erythrocytes and other tissue cells, in studying the properties of cell membranes - from the standpoint of assessing their permeability to electrolytes. In 1911, D. Donnan formulated the theory of electrolyte balance (see. Membrane equilibrium), with the help of which a cut was given to physical. explanation of the presence of ionic (potassium and chlorine) gradients in living cells, cellular electrical potentials and osmotic pressure differences. This theory continues to this day to play a leading role in understanding the role of membranes and electrolyte gradients.
Numerous studies have shown that, in addition to protein, lipid substances play an important role in cell membranes. Nathanson's theory, very popular in the 1930s, about the mosaic structure of cell membranes and the arrangement of lipids and proteins in them, arose.
By the 30s of the 20th century. the basic patterns of cell permeability were established in connection with the chemical and electrical properties of substances. It was shown that uncharged molecules penetrate cells according to their molecular radius, charged molecules - depending on their electrical properties, and liposoluble - depending on the degree of solubility in membrane lipids. The laws found formed the basis of all subsequent theoretical constructions and, in particular, in the construction of models of the structure of membranes; there was a deep interest in understanding fiz.-chem. the structure of that substrate from which living matter and membranes are built. The point of view has arisen that proteins and lipids are bound in living cells into a single lipoprotein complex with high lability, that living protein and extracted from cells are not identical. Thus, V. V. Lepeshkin developed the concept of the main lipoprotein complex, which cannot be isolated in its pure form and which he called vitaid.
V. V. Lepeshkin suggested that the instability of this complex determines the death of the protoplasm under various influences, and also that when the lipoprotein basic complex is destroyed (when lipid-protein bonds are broken), radiation - chemiluminescence should occur (see Biochemiluminescence). Despite the imperfection of the technology of that time, he managed to fix on a photographic plate the radiation of animal and plant tissues at the moment of their death under the influence of strong acids.
A large role in B.'s development belongs to the school of the American researcher J. Loeb, who raised the question of the meaning and principles of physical and chemical. study of living matter. He noted the role of physical chemistry and the prospects for its application in the study of chem. processes in living systems. His methodological guidelines were reflected in two monographs (“Dynamics of Living Matter” and “The Organism as a Whole from a Physical and Chemical Point of View”), which were translated into many European languages, including Russian (1906). Loeb carried out the idea of the need for lifetime study of fiz.-chem. processes. They were given fiz.-chem. interpretation of ion antagonism (see Ions), artificial parthenogenesis, and the properties of proteins in living systems.
One of the first processes that became the object of B.'s attention with fiz.-chem. positions, there were mechanisms that cause cell turgor, and the first object on which they began to work in this direction was erythrocytes. So, as a result of the work of Hamburger (the end of the 19th century), the hematocrit technique appeared on the osmotic properties of erythrocytes, which was used in the clinic for quite a long time. The phenomenon of hemolysis also attracted attention, the study of which led to the idea of the hemolytic resistance of erythrocytes as an important indicator of a pathological condition. Studies on the swelling of colloids under the action various substances, especially acids and alkalis, attracted the attention of pathologists, who applied colloid-chemical laws to the study of edema phenomena. The first fiz.-chem. the theory of edema was created at the end of the last century by O. Fischer. In his book Edema and Nephritis, he considered the cytoplasm as a hemogenic colloid and tried to interpret the pathological manifestations associated with edema from the colloid-chemical positions.
Research Sade (H. Schade), who created his school in honey. biophysics, led to the creation of the theory of the inflammatory process. Inflammation was considered by him as an active process of swelling of connective tissue colloids under the influence of increased acidity of the medium (primary, in his opinion, changes in the properties of colloids) with a subsequent change in their ionic composition and electric charge. He summarized the results of his research in this direction in the book “Physical Chemistry in Internal Medicine”, which was published in Russian translation in 1911. This theory was largely supplemented by the studies of D. Abramson, who explained the migration of leukocytes from the bloodstream to the inflammatory the focus from the standpoint of active electrotaxis - under the influence of electrical potentials that arise at the border of the inflammatory focus with normal tissue. The principles of this theory can be used to develop ideas about the essence of inflammation. A significant role was played by the discovery of the osmotic pressure of blood proteins while maintaining osmotic balance in the bloodstream. It caused significant progress in the creation of artificial blood substitutes. In addition to the basic provision about the need to maintain an ion-antagonistic balance, there was a requirement to create a small additional (oncotic) pressure with the help of colloidal substances. This discovery found practical use when creating blood substitutes back in the First World War.
Even at the beginning of the 20th century. one of the founders of chem. kinetics S. Arrhenius became interested in the possibility of deciphering the physical. the nature of immunological reactions by studying their kinetics. In collaboration with immunologists, he found that immunological reactions obey the laws of chem. kinetics - temperature, concentration, and that the methods of physical. analysis can be used to study the reactions occurring in living organisms. These achievements have made it possible to achieve significant success in identifying the features of the flow of chem. processes under certain physiological and pathological conditions.
Consideration with fiz.-chem. was a stage in B.'s development. point of view of the reactions that occur in living cells under the action of various pharmacol, and toxic substances, in particular narcotic. As a result of numerous studies fiz.-chem. properties of the cell (permeability, electrical properties, etc.) in the norm and their changes under the action of various narcotic substances, patterns of physical and chemical were revealed. character. Thus, it was found that anesthesia reduces the permeability of cell membranes. Trying to establish a correlation between fiz.-chem. properties of drugs and narcotic action, Overton (E. Overton, 1899) on the oil-water model found that the higher the narcotic strength, the more shifted the distribution towards the oil. Thus, the narcotic effect of a substance is greater, the higher its solubility in lipids. This model led to Overton's construction of the first biophysical theory of anesthesia, according to which the effect of anesthesia is due to the accumulation of drugs on the cell surface in the lipid phase of membranes, which leads to a change in permeability and hence to a decrease in metabolism. Another theory (Traube's theory) put forward the capillary-active properties of drugs as an acting factor. According to this theory, there should be a correlation between surface tension and narcotic activity. It was found that with the lengthening of the carbon chain and the increase in capillary activity, the narcotic effect increases accordingly (the so-called Traube rule). Works on the study of fiz.-chem. the mechanism of narcotic action caused emergence of a large number of models which in combination with fiziol, experiment allowed to expand the information on a structure of a membrane, interrelation of proteins and lipids in it. Considerable attention was paid to the study of the mechanism of action of a toxic agent on living matter. These studies were caused by the need to understand the mechanisms of action of poisonous substances used in the First World War, and to find ways to protect against them.
In Russia, K. A. Timiryazev studied the photosynthetic activity of individual sections of the solar spectrum in connection with the distribution of energy in it and the features of the absorption spectrum of chlorophyll (see Photosynthesis). A.F. Samoilov described the acoustic properties of the middle ear. MN Shaternikov, using thermodynamic concepts, conducted a study of the energy balance of the body (1910-1920). In the USSR (1919), on the personal instructions of V. I. Lenin, Ying t of biophysics of the People's Commissariat of Health of the USSR was created, which was headed by P. P. Lazarev. Extensive research was carried out here on the study of nerve conduction and excitation, the ionic theory of excitation, the theory of color vision (A. N. Tsvetkov), the mechanisms of action of radiant energy on organisms, and other scientific problems were developed. S. I. Vavilov (questions of the limiting sensitivity of the human eye), P. A. Rebinder and V. V. Efimov (study of the physical and chemical mechanisms of permeability and its connection with surface tension), and others worked here.
N. K. Koltsov had a great influence on B.'s development; biology.
His pupils widely developed questions of influence fiz.-chem. environmental factors on the vital activity of the cell and its individual structures. In 1931 the laboratory of fiz.-chem. biology in Ying-those biochemistry them. A. N. Bach in Moscow, which was led by D. JI. Rubinstein. At the All-Union Institute of Experimental Medicine (VIEM), a department of biophysics was created, in which P. P. Lazarev, G. M. Frank and others successfully worked. In the early 50s, the Institute of Biological Physics of the Academy of Sciences of the USSR was organized and the Department of Biophysics of the Biology and Soil Faculty of Moscow State University; later the departments of biophysics were organized at Leningrad University and other high fur boots.
The current state of biophysics
Advances in physics, chem. physics, the emergence of new experimental research methods, as well as the ideas and methods of cybernetics (see) and the disciplines grouped around it, opened up wide opportunities for understanding the laws of functioning of living systems and determined the growth and direction of development of modern biophysics.
B.'s methods (its physical direction) made it possible to reveal the spatial arrangement of atoms in the molecules of cellulose, hemoglobin, and others. Successes in identifying spatial disturbances of bio-molecules in some so-called. molecular pathologies (eg, sickle cell anemia). Phys. methods study the structure of nucleic acids in connection with their role in the transmission and storage of genetic information, as well as proteins and the conformation processes that occur in them. One of the most important problematic tasks of B. is the question of the mechanisms of transformations in the cells of physical organisms. energy into chemical energy (see Photobiology, Photochemistry). This also adjoins the problem of energy conversion under the action of ionizing radiation on organisms, which induce chem. transformations that cause radiation injury. The primary processes of interaction of radiation with living matter are studied by radiation biophysics. This section is closely related to the prevention of radiation injury - anti-radiation chem. protection. The other side of this issue is the problem of photosensitization (see), a classic example of a cut is the sensitization of the skin to visible light due to the accumulation of active breakdown products of hematoporphyrins there as a result of metabolic disorders in pellagra. The study of the mechanisms of sensitization is becoming more active in our time due to the appearance in the atmosphere and water of substances that have a photosensitizing effect - chemical waste. industry. B. reveals the mechanisms of their action and develops subtle methods for their detection.
In recent decades, there have been shifts in ideas about physical, chemical, and electrical processes occurring in living systems. Organisms and cells began to be considered as open systems exchanging matter and energy with the external environment, on the basis of which the concept of the stationarity of the development of biochemical reactions as a necessary condition for normal existence arose (I. Prigogine). The idea of pathology as a violation of stationarity and coordination of biochemical reactions in cells has been formed, which led to the development of new methods that allow obtaining information about the course of chemical reactions. reactions in cells in vivo (kinetic methods based on chemiluminescence, optical spectroscopy, radiospectroscopy, etc.).
From the standpoint of the thermodynamics of open systems, B. considers the problem of adaptation of cells and organisms to environmental conditions (temperature, salt composition, chemical factors, etc.). The limits of adaptation are determined by the possibility of maintaining stationarity in the development of biochemical reactions (see Adaptation, biophysical mechanisms). Methods have been developed that make it possible to set clear thresholds for stationarity disturbance and adaptation thresholds in cells; their use has created the possibility of a rapid assessment of the adaptive limits of plant and animal organisms (eg, assessment of the optimal storage conditions for human tissues intended for transplantation).
The problem of the structure and function of membranes has come to the fore. This problem has long interested B., but previously it concerned only cell membrane, while in the present, the time range has expanded and the membranes of cell organoids have become the object of attention: lysosomes, ribosomes, mitochondria, microsomes, etc. In the modern biophysical aspect, the membrane is considered as a chemical. the reactor of a cell or its individual organoid, which mainly regulates the stationary development of biochemical reactions. From B.'s point of view, the most important detail of membrane activity is the transport of electrons. In this regard, lipids and phospholipids, which are the substrate for electron transfer, attracted great attention to B.. Questions about fiz.-chem. the structure of this substrate and the mutual participation of proteins and lipids in creating the structure of membranes. The main task of B. is to obtain intravital information about the properties of these formations and their changes under various influences and pathological processes. At the same time development of methods which allow to analyze fiz.-chem. properties of cells without affecting them. Methods for measuring dielectric properties, electrical conductivity, electrical potentials, spectral characteristics, chemoluminescence, etc. are being intensively developed in this direction.
The possibilities of obtaining information about the state of membranes with the help of microelectrode technology have significantly expanded. Opportunities have opened up for measuring intracellular biopotentials and revealing the mechanisms of intracellular electrochemical processes (see Bioelectric potentials). The understanding of the mechanisms of active transport and the role of electrical gradients in the transport of various substances across cell membranes has been greatly expanded. The dominant role is played by research in the direction of revealing the nature of the transport of sodium, potassium, calcium ions and those energy sources that carry it out.
In connection with the identification of the large role of lipids in the functions of membranes, B.'s attention is drawn to low-stable lipoprotein complexes, which are the main building material of membranes. In recent years, the point of view has become widespread that these lipoprotein complexes are the most vulnerable (unreliable) parts of cells. The “unreliability” of membranes is explained by the fact that spontaneous non-enzymatic, radical, oxidation reactions (see Antioxidants) that develop with self-acceleration along a chain mechanism can occur spontaneously in their lipid part. Such uncontrolled reactions lead to the destruction of lipoprotein structures and disrupt the mechanisms of electron transport. This is so called. the phenomenon of "peroxidation of membranes" caused big interest, since the occurrence of many pathological processes is associated with it (with radiation damage, under the action of toxic substances, etc.).
Due to the fact that there are great difficulties in using the EPR method (see Electron paramagnetic resonance) in the study of living cells, and because it detects only long-lived low-active radicals, other methods are being developed. So, along with the chemiluminescence revealing short-lived radicals of the oxidizing nature and allowing to receive direct data on their presence in living cells, methods of intravital detection of radicals by a method of copolymerization (see) develop. The latter occurs when monomers labeled with radioactive isotopes are introduced into cells, which are able to polymerize according to the "radical" mechanism. The data obtained stimulated the development of the concept that active radicals and "radical" reactions are characteristic companions of pathological processes (carcinogenesis, inflammatory reactions, etc.).
All these studies posed a new problem - the problem of studying the mechanisms of stabilization of intracellular membranes and identifying individual factors that regulate oxidative processes. Attention has been drawn to the antioxidants or antioxidants of membrane lipids (tocopherol, ubiquinone, etc.) and their antagonists.
The study of antioxidants as regulators of oxidative balance in the lipid structures of cells is the most important problem of modern B.
Research is being actively carried out in the field of studying muscle contraction, where mechanochemical concepts are widely involved (see Mechanochemical processes). Of considerable interest is the study of the state of water in the cell, where new possibilities have opened up in connection with the development of the NMR method of nuclear resonance (see Nuclear Magnetic Resonance). Significant progress is observed in the field of studying the mechanisms of action on the body of external physical. factors [eg, the action of a magnetic field (see) on the processes of hematopoiesis; much research is devoted to the action of the electric field and the factors associated with it].
In the USSR, in all universities (biological and biological-soil faculties) and honey. Higher education institutions introduced the B. course with practical exercises as a general education subject.
In 1963, the Faculty of Medicine and Biology was established at the 2nd MMI with a department of biophysics, the task of which is to train medical biophysicists. There are a number of biophys. scientific centers in which research work is carried out on B.
In the USSR, these are the Institute of Biophysics of the Academy of Sciences of the USSR (Pushchino-on-Oka), the Institute of Biophysics of the Ministry of Health of the USSR, the Department of Biophysics of the Biological Faculty of Moscow State University, the Department of Biophysics of the Physics Faculty of Moscow State University, the Department of Biophysics of the Institute of Physics of the Siberian Branch of the USSR Academy of Sciences and etc.
Abroad: Great Britain - Laboratory of Biophysics of London University, departments of biophysics in Cambridge and Edinburgh Universities; GDR - Institute of Biophysics (Berlin); PRC - Institute of Biophysics (Beijing); Poland - Institute of Biochemistry and Biophysics of the Polish Academy of Sciences (Warsaw); USA - Yale University, Rockefeller University, Harvard University, Univ. Washington (St. Louis), Massachusetts Institute of Technology; France - Institute of Physical and Chemical Biology (Paris); Germany - Institute of Biophysics of the Society. Max Planck (Frankfurt am Main), Institute of Biological and Medical Physics, Göttingen University; Czechoslovakia - Institute of Biophysics (Brno); Japan - universities in Tokyo and Osaka.
International congresses on biophysics, convened by the International Union of Theoretical and Applied Biophysics, regularly gather (since 1961), representatives of the USSR enter the Central Council. Societies of biophysicists exist in the USA and Great Britain. In Moscow there is a biophysics section of the Moscow Society of Naturalists.
Modeling in biophysics
The modeling method in B. is applied to knowledge fiz.-chem. mechanisms underlying physiological and pathological processes. The main task of such modeling is to isolate the phenomenon under study in a "pure" form, an attempt to filter a particular process from disturbing factors and accompanying phenomena in a complex system, to show the essence of the process under study.
First of all, for understanding the physical and chemical. processes occurring in the cells of higher organisms are used as models for more simple organisms or cells, where the mechanisms being studied are simpler. For example, when studying the role of ionic processes in the conduction of excitation in the nerves of higher animals, the nitella algae, as well as the nerve fibers of the squid, were used as a model. Contractile myonemes of protozoa and muscle fibrils of lower organisms have been widely used to understand the process of muscle contraction. In the study of biol, the action of radiant energy, cell cultures are widely used, on which it was possible to eliminate the influence of remote factors emanating from the systems of complex organisms.
Along with the listed biological models are applied also purely fiz.-chem. models that are built from substances close to those from which biological substrates are built. Such simple models can actually reproduce certain phenomena and are used to test any hypotheses.
In the absence of direct information about the structure of biological membranes, artificial models have played an important role in the development of ideas about the structure of membranes and the role of this structure in the function of cell membranes and organelles. There are many models of membranes built from lipids, phospholipids, and proteins in various structural combinations. In such membranes, it was possible to imitate, for example, the phenomena of selective permeability. Models were used to study the effects of drugs and it was possible to derive the laws of the narcotic effect and evaluate the strength of the effects of drugs on higher organisms.
There are also many models of cell division known in the literature, in which it was possible to reveal the role of substances with surface activity in this process; there are models of muscle contraction that have proven the role of some physical. factors in changing the configuration of protein polymers; artificially prepared gels served as a model for the pathological permeability of capillaries for leukocytes, etc.
In B. use and purely physical models. Such models include, for example, combinations of electrical resistances and capacitances, which, when an electric current is passed, reproduce patterns characteristic of living systems. However, in a number of cases, such models are not models in the strict sense, since they do not say anything directly about the mechanism of the biological phenomenon under study and reproduce only the behavior of the biological system. Therefore, they can be called analogs, but they turn into models only with the introduction of a number of additional assumptions.
With the transition to considering the body and its functions as a complex complete system the use of mathematical modeling began. In this case, the models are built as the sum of interacting processes described by differential equations. Such models make it possible to establish the relationship between physical and chemical. processes. Calculations are carried out on a computer; other mathematical techniques are involved in the solution, in particular, graph theory, which makes it possible to solve such problems without resorting to differential equations. At the same time, cybernetic methods are used that are applied to the analysis of complex biological systems, for example, communications fiz.-chem. structures of biological structures with physiological functions (in particular, lipoproteins in the development of pathological processes).
Bibliography: Ackerman Yu. Biophysics, trans. from English, M., 1964; Bayer W. Biophysics, trans. from German., M., 1962; Biophysics, ed. B. N. Tarusova and O. R. Collier. Moscow, 1968. In about l-ken stein M. V. Molecules and life, M., 1965, bibliogr.; P and with s n with to and y A. G. Biophysical chemistry, M., 1968; G e n t^-GyörgyiA. Bioenergetics, trans. from English, M., 1960; Setlow R. and Pollard E. S. Molecular biophysics, trans. from English, M., 1964, bibliography; Taru-s about in B. N. Fundamentals of biophysics and biophysical chemistry, part 1, M., 1960; he, Superweak glow of living organisms, M., 1972.
Periodicals- Biophysics, M., since 1956; Bulletin of experimental biology and medicine, M., since 1936; Reports of the Academy of Sciences of the USSR, Biological Series, M., since 1966; Molecular biology, M., since 1967; Scientific reports of the higher school, Biological sciences, M., since 1958; Radiobiology, M., since 1961; Advances in Biological and Medical Physics, N. Y., since 1948; Archives of Biochemistry and Biophysics, N. Y., since 1951 (1942-1950 - Archives of Biochemistry); Biochimica et biophysica acta, Amsterdam, since 1947; Biophysical Journal, N. Y., since 1960; Bulletin of Mathematical Biophysics, Chicago, since 1939; Cold Spring Harbor Symposia on Quantitative Biology, N. Y., since 1933; Progress in Biophysics and Biophysical Chemistry, Oxford, since 1950.
Modeling in B.- Mathematical modeling of life processes, ed. M. F. Vedenova et al., M., 1968; Modeling in biology, trans. from English, ed. Edited by N. A. Bernstein. Moscow, 1963. Ut e-u sh E. V. and Ut e U sh 3. V. Introduction to cybernetic modeling, M., 1971.
B. N. Tarusov.
Lecture #1The subject and tasks of biophysics
Biophysics as a biomedical science that studies the mechanisms of physical and physico-chemical processes in biological systems. Place of biophysics in a number of fundamental biological and medical disciplines, connection with biological and medical sciences. Brief historical outline of the development of biophysics. Methods and directions of modern biophysics.
The subject of biophysics is the study of the physical and physico-chemical processes underlying life. There are more capacious definitions of biophysics. For example, the Nobel Prize winner A. Szent-Györgyi argued that biophysics is “everything that is interesting”. The term “biophysics” has been fixed in the scientific literature since 1892, when Karl Pearson, the author of the book “Grammar of Science”, stated on its pages: “... a science that tries to show that the facts of biology - morphology, embryology and physiology form special cases applications of general physical laws, was called etiology ... Perhaps it would be better to call it biophysics. A. Fick and after him other German scientists called this field of knowledge medical physics, but the French physiologist J. A. d "Arsonval, even before K. Pearson's proposal, preferred the phrase "biological physics" to the term "medical physics".
Modern biophysics explores the mechanisms of physical and physico-chemical processes in biological systems at the submolecular, molecular, supramolecular, cellular, tissue, organ and organism levels.
By the nature of the objects of study, biophysics is a typical biological science. According to the methods of studying bioobjects and analyzing the results of research, biophysics is a kind of branch of physics (according to M.V. Volkenstein, “biophysics is the physics of life phenomena”). It is at the forefront of those areas of biology that transform this ancient area of human knowledge from the humanities into an exact science. The introduction of the physical principles of the analysis of biological phenomena into medicine allows it to become not only an art, but also a science. This is the special role of biophysics among other medical theoretical disciplines.
Biophysics is often spoken of as a new, young science. So, on November 9, 1934, P.L. Kapitsa wrote: “Biophysics is a completely new field, it came along with biochemistry to replace the old classical physiology. Instead of studying physiological processes as a whole ... biophysics and biochemistry study the individual elements of a living being and try to explain its function through the laws of physics and chemistry. Indeed, in a separate scientific discipline biophysics emerged relatively recently, but the beginnings of biophysics arose immediately after the appearance of work in the field of experimental physics. So, some of the research of G. Galileo (measuring body temperature, determining the work done by a person, etc.) can be attributed to biophysical research.
The desire to explain the processes of life of man and animals by physical laws was very characteristic of the work of many scientists of the 17th and 18th centuries. (R. Boyle, R. Hooke, I. Newton, P.S. Laplace, A.L. Lavoisier, M.V. Lomonosov and many others). 19th century became a century of celebration analytical methods in the study of biological phenomena. These methods have received the greatest development in physiology, in the depths of which modern biophysics was born. Many physiological processes, up to nervous activity, have been tried to be explained on the basis of physical laws. Unlike similar attempts by predecessors, such explanations were largely confirmed experimentally. Hermann Helmholtz measured the speed of propagation of a nerve impulse. Emile Dubois-Reymond studied the bioelectrogenesis of almost all organs and tissues of the body. Ernst Weber explained some of the properties of hemodynamics based on physical laws. Outstanding discoveries have been made in the field of biophysics of the sense organs - suffice it to mention the Weber-Fechner law.
However, the 19th century determined a very characteristic trend in the subsequent development of biophysics. One of the first scientists who noticed and approved this trend was Ivan Mikhailovich Sechenov, the father of Russian physiology. With no less reason, he can be called the founder of Russian biophysics. He used the methods of mathematics and physical chemistry to study respiration, and established quantitative laws for the dissolution of gases in biological fluids. In the works of I.M. Sechenov, the most promising path for the development of physiology and biophysics, associated primarily with physical chemistry, can be traced. In his doctoral dissertation (1860) I.M. Sechenov stated: “A physiologist is a physico-chemist who deals with the phenomena of an animal organism.”
However, only in the XX century. biophysics became an independent science. Since then, she began to study the fundamental problems of biology: heredity and variability, ontogenesis and phylogenesis, metabolism and bioenergetics.
Most researchers (biophysicists) of the XVII−XIX centuries. considered a living organism as a physical system, and the main method of such a study of biological phenomena was the search for external analogies. It should be noted that even now such a technique is used in biophysics not without success. For example, muscle contraction can be modeled by an inverse piezoelectric effect, amoeboid cell movement by the movement of a mercury drop in an acid solution, conduction of a nerve impulse by scratch migration along an iron wire treated with nitric acid (Lilly model), etc.
The cognitive value of such models is rather limited. Often, when modeling the same biological phenomenon, they replace one another after the appearance of new technical devices. For example, reflex activity was considered at the time of R. Descartes by analogy with the operation of a steam engine, at the beginning of the last century - a telephone exchange, now - an electronic computer. However, similar (phenomenological) models are also needed. They allow clarifying some details of phenomena already understood in principle, creating bionic systems that use the laws of biological organization to build complex technical devices, such as robots. And yet, this useful direction of physical modeling is not the main one in solving cardinal biophysical problems.
primary goal biophysical research consists in elucidating the intimate (internal) mechanisms of biological processes, and not in considering external analogies. It is generally accepted that living organisms are complex physico-chemical systems. Therefore, not physical, but physicochemical modeling turned out to be the most fruitful. It led to the creation of the ionic theory of excitation, the discovery of the nature of bioelectrogenesis, the elucidation of the properties of biological membranes, etc. The achievements of biophysics in recent years have been especially significant along this path.
Essentially, modern biophysics is physical chemistry and chemical phizika of biological systems. It is this direction that is leading in the work of the two largest biophysics institutes of the Russian Academy of Sciences in the world, which are located in the city of Pushchino near Moscow. Many research institutions of the Academy of Sciences, the Academy of Medical Sciences, and the Ministry of Health of Russia are now dealing with the problems of biophysics. Among them are the Institutes of Physical Chemistry and Chemical Physics of the Russian Academy of Sciences, the Institute of Biophysics of the Ministry of Health of Russia. The development of biophysics in our country is also carried out by university departments of biological physics.
Biophysics is a frontier area of knowledge, moreover, the boundaries between it and a number of other biological sciences are rather arbitrary. When drawing these boundaries, they proceed from the very definition of the subject of biophysics - biophysical studies include studies that reveal the physical, as well as physico-chemical mechanisms of biological processes. In biophysical research, the basic principle of experimental study of nature is applied - a quantitative analysis of the body's reactions to certain stimuli with the construction of functional dependencies between them. The processes of vital activity receive a strict interpretation in the form of quantitative patterns, which are an abstract form of expression of the functional dependence of the reaction on the stimulus.
The functions of the body have been studied since time immemorial physiology. At different times, the content of physiology has changed. Now she considers a function as a form of activity with a certain final result, the manifestation of which is physiological properties (Shidlovsky, 1981). Their internal mechanisms cannot be penetrated using traditional physiological approaches to the study of functions. These mechanisms, since they are of a physical and chemical nature, are studied by biophysics and biochemistry. The difference between the tasks of biophysics and physiology in the study of body functions can be illustrated by the following example. Investigating biopotentials, a biophysicist is primarily interested in the mechanism of occurrence of electromagnetic processes in living tissues, the physicochemical foundations of this phenomenon, its energy supply, while for a physiologist, biopotentials are indicators of the vital activity of an organism, serve as a quantitative characteristic of the most important physiological properties (primarily excitability) . So, according to the electrocardiogram, the physiologist judges the properties of the heart muscle (automatism, excitability, conductivity). He is less interested in the physicochemical nature of electrogenesis in the myocardium; this is the main task of the biophysical study of electrical processes in the heart.
Biochemistry, like biophysics, also seeks to penetrate the mechanisms of physiological phenomena, but studies their chemical nature. The difficulties in distinguishing between biophysical and biochemical research are understandable, but this must be done. “There is no doubt,” academician G.M. Frank (1974), - that any manifestations of life and living organisms in general are ultimately "chemical machines". However, despite the primacy of chemistry, chemical language and chemical concepts are not sufficient to reveal the material essence of life phenomena. This primarily applies to the ways of energy transformation, the nature of interaction forces and various physical processes, such as, for example, the generation of electrical potentials, the emergence of mechanical energy, control and regulation mechanisms.
Biophysical methods are created on the basis of physical and physico-chemical methods of studying nature. They should combine properties that are difficult to combine: high sensitivity and high accuracy. This condition is met, first of all, by the achievements of modern electronics. Very fruitful use optical methods. Various methods of spectroscopy are widely used, including radiospectroscopy (methods of electron paramagnetic resonance - EPR and nuclear magnetic resonance - NMR). Radioisotope techniques have long come into use.
Any research requires that the recording devices do not introduce distortions into the process being studied. For a biophysical experiment, compliance with this requirement is especially important. The famous Soviet biophysicist B.N. Tarusov believed that this requirement contains the most important feature of biophysical methods, which distinguishes them from the use of similar methods. methodological techniques in other areas of physics. This somewhat exaggerated formulation of the specifics of biophysical methods has certain grounds. It is difficult to compare any physical system with a living organism because of the extraordinary high sensitivity the latter to any influence on him. They do not just disrupt the normal course of biological processes, but cause complex adaptive reactions, which are diverse in different organs and under different conditions. The distortion of the meaning of true phenomena may turn out to be so significant that it becomes impossible to correct artifacts (phenomena that are not characteristic of the object under study in natural conditions and that arise in the course of its research), since the correction methods used successfully in physics and technology are often fruitless in biophysics .
In order to better understand the areas of application of biophysical methods, we will consider the main directions of scientific research in biophysics. According to the decision of the International Association of General and Applied Biophysics, these include research at the molecular and cellular levels, as well as the biophysical study of sensory organs and complex systems.
Methods and directions of modern biophysics.Molecular biophysics studies the functional structure and physico-chemical properties of biologically important (biologically functional) molecules, as well as the physical processes that ensure their functioning, explores the thermodynamics of biological systems, energy and charge transfer through biomolecules, quantum mechanical features of their organization. This part of molecular biophysics is gradually separated into a new section called quantum biophysics. In general, the task of molecular biophysics is to reveal the physicochemical mechanisms of the biological functionality of molecules.
Works on cell biophysics devoted to the physical and physico-chemical properties of cellular and subcellular structures, the patterns of cell division and differentiation, the characteristics of their metabolism (metabolism), as well as biophysical mechanisms specialized functions cells (muscle contraction, secretion, nerve impulses, etc.).
Biophysics of the sense organs reveals the physical and physico-chemical mechanisms of perception of specific stimuli by the receptor apparatus of sensory systems (analyzers) of humans and animals (at the quantum, molecular, cellular levels).
Task biophysics of complex systems consists in solving general physical and biological problems (the origin of life, heredity, variability, etc.) on the basis of physical and mathematical modeling of the most important biological processes.
Many biophysicists insist on singling out one more area of biophysical research − biophysical foundations of ecology. Its content is to elucidate the mechanisms of action on the body of physical and chemical environmental factors. There is a tendency to identify all biophysics with molecular biophysics, which is reflected in the textbook by M.V. Volkenstein "Biophysics", published for students of biological and physical faculties of universities. Such a limitation can be allowed to determine the area of the most relevant scientific research in modern biophysics, although not everyone agrees with this. So, Academician G.M. Frank back in 1974 argued that “the center of gravity of the physicochemical consideration of the basis of life phenomena is now shifting to the field of cell biology,” since “life phenomena arise only in a system called a cell,” and, according to E.B. Wilson (1925), “the key to every biological problem must be sought in the cell”, and modern biophysics began to have methods that make it possible to make the cell the object of an accurate physical experiment. This does not mean that other areas of biophysical research are assigned a supporting role. According to G.M. Frank, in the development of biophysics, "... the continuity of the line of research from the section that we have designated as" molecular biophysics ", further through the biophysics of the cell to the biophysics of complex processes" should be observed.
Biophysics is a science that studies the physical and physico-chemical processes that occur in biosystems at different levels of organization and are the basis of physiological acts. The emergence of biophysics occurred as progress in physics, mathematics, chemistry and biology contributed.
Living organisms are an open, self-regulating, self-reproducing and developing heterogeneous system, the most important functional substances in which are biopolymers: proteins and nucleic acids of a complex atomic and molecular structure.
Tasks of biophysics:
1. Disclosure of general patterns of behavior of open non-equilibrium systems. Theoretical substantiation of thermodynamic (t/d) foundations of life.
2. Scientific interpretation of the phenomena of individual and evolutionary development, self-regulation and self-reproduction.
3. Finding out the links between the structure and functional properties of biopolymers and other biologically active substances.
4.Create and theoretical background physico-chemical methods for studying biological objects.
5. Physical interpretation of an extensive complex of functional phenomena (generation and distribution of a nerve impulse, muscle contraction, reception, photosynthesis, etc.)
Sections of biophysics:
· Molecular - studies the structure and physico-chemical properties, biophysics of molecules. The main objects of study of molecular biophysics are functionally active substances, among them proteins and nucleic acids.
· Biophysics of the cell - studies the features of the structure and functioning of cellular and tissue systems. Cell biophysics deals with the supramolecular structures of a living cell, among which a special place is occupied by the membrane structures of cells and subcellular structures.
· Biophysics of complex systems - studies the kinetics of bioprocesses, the behavior in time of various processes inherent in living matter and the thermodynamics of biosystems. Biophysics of complex systems considers living organisms different levels organization from the standpoint of physical and mathematical modeling. The objects of study in this case are cell communities, living tissues, physiological systems, populations of organisms. Building models is one of the main stages of biophysical research. A living organism is a very complex system, not always accessible for an accurate physical experiment. In this case, the use of physical, analog, mathematical models becomes fruitful. Every major discovery in biophysics comes from the application of models.
The presentation of biomacromolecules in the form of crystals made it possible to establish the molecular structure of hemoglobin and myoglobin. An important role was played by the analog electrical model of the excitable membrane in the studies of Hodgkin and Huxley. In membrane biophysics, physical models of membranes in the form of mono- and bimolecular lipid films are widely used. With the development and improvement of computer technology, modeling receives a new development.
Sciences such as biology, medicine, agricultural sciences are becoming more and more precise. In this case, it is difficult to overestimate the role of biophysics, which is called upon to investigate the phenomena of life using physical concepts and methods.
History of the development of biophysics.
Mathematical models describe a whole class of processes or phenomena that have similar properties or are isomorphic. The science of the late 20th century, synergetics, showed that similar equations describe processes of self-organization of a very different nature: from the formation of clusters of galaxies to the formation of plankton spots in the ocean.
Despite the diversity of living systems, they all have the following specific features that must be taken into account when building models.
All biological systems are complex multicomponent, spatially structured, the elements of which have individuality. When modeling such systems, two approaches are possible. The first one is aggregated, phenomenological. In accordance with this approach, the defining characteristics of the system are singled out (for example, the total number of species) and the qualitative properties of the behavior of these quantities over time (the stability of the stationary state, the presence of oscillations, the existence of spatial heterogeneity) are considered. This approach is historically the most ancient and is characteristic of the dynamic theory of populations.
Another approach is a detailed consideration of the elements of the system and their interactions. The simulation model does not allow analytical study, but its parameters have a clear physical and biological meaning, with good experimental knowledge of system fragments, it can give a quantitative prediction of its behavior under various external influences.
Reproducing systems (capable of autoreproduction). This most important property of living systems determines their ability to process inorganic and organic matter for the biosynthesis of biological macromolecules, cells, organisms. In phenomenological models, this property is expressed in the presence of autocatalytic terms in the equations that determine the possibility of growth, the possibility of instability of a stationary state in local systems, and the instability of a homogeneous stationary state in spatially distributed systems.