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N L Delone

Publications and source records attributed to N L Delone.

12 recordsLinked to original sources
PubMed1969

Some results of radiobiological studies performed on Cosmos-110 biosatellite.

The experiment carried out on the Cosmos 110 biosatellite is a step further in radiobiological investigations performed in outer space and differs appreciably from flight experiments conducted on board the Vostok and Voskhod spacecraft. The difference lies, firstly, in the integral dose of cosmic radiation. According to the onboard dosimeter readings, it was 12 rad at an average dose rate of 500 mrad/day during the biosatellite flight, whereas in previous biological flight experiments, as is well known, the total dose was below 80 mrad (on a five-day flight of Vostok 5) at a dose rate of 80 to 20 mrad/day. Secondly, during the biosatellite mission, cosmic radiation originated not from the primary cosmic radiation as was the case in the Vostok and Voskhod flights but mainly from the Earth's radiation belts. Thirdly, the duration of the Cosmos 110 flight was far longer than that of any previous mission: the effect of weightlessness lasted for about 22 days. The paper presents results of investigations performed on E. coli K-12 lambda lysogenic bacteria, Tradescantia microspores, dry seeds of higher plants, different Chlorella strains and an intact plant of Tradescantia paludosa. The biological effect of space flight factors was evaluated by various physiological, cytogenetic, genetic and microbiological techniques. Similar to previous experiments carried out on board the Vostok 3-6 spacecraft, tests with lysogenic bacteria revealed a statistically significant induction of moderate bacteriophage. The induction value was shown to lag behind the mission duration dependence level. This seems to be related to a change of inducibility properties of lysogenic bacteria and a reduction of the yield range of phages per bacterial cell. Other tests (duration of the latent period, formation pattern of phage components) indicated no significant differences between test and control objects (N.N. Zhukov-Verezhnikov, N.I. Rybakov, V.A. Kozlov et al.). A study of protective properties of chemical compounds of different types in relation to the bacteriophage induction demonstrated that preparations of the aminothiolic group produced a high antimutagenic effect (V.A. Kozlov, N.I. Rybakov et al.). A postflight cytological analysis of Tradescantia paludosa microspores indicated their changes of three types: chromosome aberrations, mitotic disturbances and disorders of growth processes in the cell. Examinations of dry seeds of wheat, barley, pine and other plants, as well as of Allium cepa bulbs, gave evidence of a diverse effect of space flight factors on both physiological processes and hereditary structures of the objects. In some cases an increased percentage of seed germination, stimulation of their growth and a significant increase of aberrations were found. An investigation of the occurrence frequency of visible mutations in reaction cell cultures of different Chlorella strains (LARG-1, LARG-3 and others) showed no significant differences between the test and control material. Some cultures taken under a more detailed study indicated a delay with which cells entered the first sporulation and a greater amount of cells that divided into a lesser than usual number of autospores. In addition, test variants of the strains showed a slightly reduced survival of Chlorella cells. The reduction appeared to be statistically significant for the LARG-3 strain only (E.N. Vaulina et al.). A postflight examination of the appearance of the Tradescantia paludosa plant showed that it retained good turgor; its leaves were dark green and several bright flowers bloomed. No signs of its inhibition or etiolation were noted. As compared to the control, the test plant grew noticeably and the stem became crooked. Certain problems of biological indications of outer space are discussed.

Chlorella↗
PubMed1965

Results of biological experiments carried out under conditions of "Vostok" flights with the participation of cosmonauts A.G. Nikolajev, P.R. Popovich and V.F. Bykovsky.

The data are presented on a study of the effect of space flight factors, particularly of weightlessness and radiation, on the fertilization, growth and development of Drosophila melanogaster and on the mechanism of heredity in Tradescantia paludosa. Copulation, oviposition and development of Drosophila are shown to be possible under 4-day weightless conditions. A distortion in the sex ratio has been registered in the cultures of flies grown in flight. Three types of changes in Tradescantia microspores brought about by flight factors have been revealed, i.e. chromosome rearrangements, distortions in the mitotic mechanism and stimulation of growth processes in the cell. It is suggested that rearrangements of chromosomes are caused by the action of vibrations and accelerations while distortions in the mechanism of mitosis are mainly related to the weightlessness effect.

Animals↗
PubMedDate not supplied

[Human adaptive phenotypes in physiology and medicine].

The study of pathological and physiological features associated with genetic syndromes has gained increasing momentum over the past two decades. In this paper, the definition of adaptive phenotypes is presented and the complexities and obstacles to progress in this field are summarized. This is a problem of general biology and is related to genetic specificity of every organism. The concept of individual norm of man's responses is to a certain extent associated with the doctrine of constitutions. From the practical point of view it is suggested to use in medicine and physiology an individual-constitutional approach and the term adaptophenotype (adaptive phenotype) which means a stable complex of genetic and phenotypical characteristics. It can be determined using clinical, physiological, genealogical, and dermatoglyphic methods, methods of genetic markers, phenotypical analysis, etc. A variety of developmental and physiological characteristics can form the "adaptophenotype" is used in general application, it is used to refer to a broad range of human functioning including pathological characteristics (somatic disorders), psychopathology (mental disorders), physiological and behavior problems. Genetic approaches help reveal not only individual hereditary parameters which manifest as signs but also latent pathological and physiological characteristics that may be used for professional selection. The delineation of adaptive phenotypes is a difficult enterprise, not that should not dissuade clinicians and researchers from undertaking it.

Adaptation, Physiological↗
PubMedDate not supplied

[Genetic aspects of man's adaptation to long-term space flight].

Human genetics may play an important role in medical support of prolonged space flights, which raise serious life sciences questions: what is a normal response or, more specifically, what is norm or pathology. This is a problem of general biology and is related to genetic specificity of every organism. The theoretical basis of pertinent researches is general genetics and cytogenetics with their concepts about the structure and function of the eukaryotic genome. The concept of an individual norm of man's responses is to a certain extent associated with the doctrine of constitutions. From the practical point of view it is suggested to use in space genetics an individual-constitutional approach and the term adaptophenotype (adaptive phenotype) which means a stable complex of genetic and phenotypical characteristics. It can be determined using clinical, genealogical, cytological, and molecular methods, methods of genetic markers, phenotypical analysis, etc. Genetic approaches help reveal not only individual hereditary parameters which manifest as signs but also latent pathological characteristics that may be used for cosmonaut selection. Identification of certain phenotypes of man, i. e. adaptophenotypes, that are suitable for life in space, also means identification of specific genotypes with their response norm at the level of the somatic cell genotype and at the level of a gamete. The role of space genetics is associated with the study of gene, chromosome and population levels of adaptation to long-term space missions. Until recently these levels of adaptation have been neglected. The program of studying human genetics in space proposed here covers both medical aspects and evolutionary approaches.

Adaptation, Physiological↗
PubMedDate not supplied

[Problems of variability in weightlessness].

The genetic (cytogenetic) effects of microgravity have been under study for about 30 years. This line of research developed through three periods. Initially, biologists raised the question whether microgravity may act as a lethal factor or a strong mutagen. Many flight experiments gave a negative answer to it. The major goal of the second period was to identify the effects of microgravity at the chromosomal and cellular levels. Such effects, statistically significant although small in value, were detected in Tradescantia paludosa and Drosophila melanogaster microspores. These findings were confirmed by American and--later--by European investigators. The third period addresses the entire problem of variability in microgravity. This approach can be implemented on the basis of a comprehensive program of research that will include experiments at different levels: from the gene to the population level. The basic objective of the program is to clarify the role of the genetic apparatus in the adaptation of living systems to microgravity and, consequently, to determine the role of gravity in the evolution of life on the Earth.

Adaptation, Biological↗