RESUMO
Three french laboratories have participated in the Free Flyer Biostack experiment. Artemia cysts, tobacco seeds and rice caryopsis and embryos were used. Biological objects in monolayers were dead. In opposite, a large fraction of samples used in bulk survived. A stimulatory effect occurred in the first steps of development in Artemia cysts. In fact, the larval survival was unchanged or slightly reduced. In tobacco a drastic decrease in germination and survival rate was observed. Space flight did not induce genetic changes. In rice, results depend on the variety which was investigated; the growth rate stimulation in flight samples is discussed with respect to controls.
Assuntos
Artemia/efeitos da radiação , Radiação Cósmica , Germinação/efeitos da radiação , Nicotiana/efeitos da radiação , Oryza/efeitos da radiação , Plantas Tóxicas , Voo Espacial/instrumentação , Animais , Artemia/embriologia , Artemia/genética , Raios gama , Oryza/genética , Oryza/crescimento & desenvolvimento , Sementes/efeitos da radiação , Astronave , Dosimetria Termoluminescente , Fatores de Tempo , Nicotiana/genética , Nicotiana/crescimento & desenvolvimentoRESUMO
Artemia (Brine shrimp) cysts and tobacco seeds, dormant biological material devoid of metabolic activity, were flown aboard the Soviet Biocosmos 1887 in order to investigate the effects of cosmic rays. Artemia cysts and tobacco seeds were used in bulk or in monolayers sandwiched with track detectors. Biological and physical units were located outside and inside the spacecraft. Stacks included lead shielding in order to expose the objects to different doses of radiation. Total dosimetry was performed using thermoluminescent detectors. In spite of low levels of doses, the space flight resulted in a decrease in developmental capacity of Artemia cysts, and in a higher mutation rate in tobacco seeds. The more obvious responses occurred, in both cases, in biological objects exposed to the highest doses. These results are compared to those of previous space experiments.
Assuntos
Artemia/efeitos da radiação , Radiação Cósmica , Nicotiana/efeitos da radiação , Plantas Tóxicas , Sementes/efeitos da radiação , Voo Espacial , Ausência de Peso , Animais , Artemia/embriologia , Artemia/crescimento & desenvolvimento , Embrião não Mamífero/embriologia , Embrião não Mamífero/efeitos da radiação , Desenvolvimento Embrionário , Meio Ambiente Extraterreno , Mutação , Doses de Radiação , Proteção Radiológica , Radiometria , Sementes/genética , Dosimetria Termoluminescente , Nicotiana/genéticaRESUMO
Male and female mice of the BALB/c strain were placed on the floor of a hut built at a site of the Permian Basin of Lodève (Southwest France) where the dose rate of gamma radiation amounts to about 10 mrad/h. In previous experiments such high natural radioactivity was shown to induce point mutations in plant material as well as chromosome aberrations in somatic cells of experimental mammals. Controls were kept near the radioactive site under comparable conditions. After the exposure period, the animals were mated in our laboratory, with control mice of the same strain. Due to the high radiosensitivity of mouse oocytes, the fertility of the exposed females was drastically reduced in spite of the fact that the dose received did not exceed 13.8 rad. The fertility of the males exposed to 13 rad, 15 rad or to 45 rad was increased above the control values but was reduced for the animals receiving 63 rad. Analysis of the results show that the differences in fertility are mainly due to a decrease in the number of sterile pairs when males have been exposed to doses upto 45 rad and to an inverse effect when animals received 63 rad. Since histology and weight of the testes suggest that the germ cell population was normal, one has to conclude that the variations in fertility result from physiological effects.
Assuntos
Exposição Ambiental , Fertilidade/efeitos da radiação , Animais , Relação Dose-Resposta à Radiação , Feminino , Raios gama , Tamanho da Ninhada de Vivíparos/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , GravidezRESUMO
The radiobiological properties of the heavy ions of cosmic radiation were investigated on Spacelab 1 by use of biostacks, monolayers of biological test organisms sandwiched between thin foils of different types of nuclear track detectors. Biostacks were exposed to cosmic radiation at several locations with different shielding environments in the module and on the pallet. Evaluations of the physical and biological components of the experiment to date indicate that in general they survived the spaceflight in good condition. Dosimetric data are presented for the different shielding environments.
RESUMO
The radiobiological properties of the heavy ions of cosmic radiation were investigated on Spacelab 1 by use of biostacks, monolayers of biological test organisms sandwiched between thin foils of different types of nuclear track detectors. Biostacks were exposed to cosmic radiation at several locations with different shielding environments in the module and on the pallet. Evaluations of the physical and biological components of the experiment to date indicate that in general they survived the spaceflight in good condition. Dosimetric data are presented for the different shielding environments.
Assuntos
Íons Pesados , Monitoramento de Radiação/instrumentação , Radiobiologia , Voo Espacial/instrumentação , Ausência de Peso , Animais , Arabidopsis/efeitos da radiação , Artemia/efeitos da radiação , Desenho de Equipamento , Transferência Linear de Energia , Radiometria , Eficiência Biológica Relativa , Sordariales/efeitos da radiação , Esporos BacterianosRESUMO
Caryopses and isolated embryos from Rice (Oryza sativa L.) and Tobacco seeds (Nicotiana tabacum L. variety Xanthi) were studied in the Biobloc III container aboard the Soviet orbital space station SALYUT 7. The recovery from radiation damage under conditions of space flight was observed for rice caryopsis and embryos gamma irradiated (Co 60, 50 grays) prior to launch. There was a large decrease in the percentage of germinating seeds from the Tobacco strain tested when the seeds were exposed to heavy ions. Among the germinating plantlets there were few morphological anomalies. Furthermore, there was a significant greater amount of genetic change in those samples held in grids as compared to those in bags.
Assuntos
Íons Pesados , Brotos de Planta/efeitos da radiação , Sementes/crescimento & desenvolvimento , Sementes/efeitos da radiação , Voo Espacial , Ausência de Peso , Radiação Cósmica , Cotilédone/efeitos da radiação , Raios gama , Germinação/efeitos da radiação , Oryza/crescimento & desenvolvimento , Oryza/efeitos da radiação , Brotos de Planta/crescimento & desenvolvimento , Plantas Tóxicas , Sementes/genética , Nicotiana/genética , Nicotiana/crescimento & desenvolvimento , Nicotiana/efeitos da radiaçãoRESUMO
Male mice of the BALB/c strain were placed on the floor of a hut built at a site of Southwest France where the dose rate of gamma radiation amounts to about 10 mrad/h. Controls were kept near the radioactive site under comparable conditions. The doses of gamma rays received during a seven month period ranged from 0.1275 rad for the controls to 45 rad and 63 rad for the exposed animals. Due, possibly, to an effect on the libido exposure to 45 rad increased the fertility whereas the animals given 63 rad produced less offspring than the controls.
Assuntos
Fertilidade/efeitos da radiação , Animais , Radiação de Fundo , França , Raios gama , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Doses de RadiaçãoRESUMO
Artemia cysts, lettuce and tobacco seeds were flown aboard the Cosmos 1129 for 19 days. A correlative method was used in order to determine the passage of cosmic heavy ions (HZE particles) through the biological test objects. This space flight resulted in a decrease on hatchability, nucleic acid and protein synthesis in hydrated Artemia cysts. HZE particle effects on plant cellular chromosomes are confirmed. In tobacco seeds, a stimulating effect on germination rate and a higher frequency of abnormalities were observed. Dormant biological objects are a very suitable material to study cosmic ray effects: these objects can be arranged in monolayers and sandwiched between visual track detectors in order to determine the passage of the cosmic heavy ions (HZE particles). On the other hand this method allows us to study effects of microgravity and those of the protonic component of cosmic rays in the objects not hit by the HZE articles.
Assuntos
Artemia/crescimento & desenvolvimento , Radiação Cósmica , Lactuca/crescimento & desenvolvimento , Nicotiana/crescimento & desenvolvimento , Plantas Tóxicas , Sementes/crescimento & desenvolvimento , Voo Espacial , Ausência de Peso , Animais , Artemia/metabolismo , Artemia/efeitos da radiação , Aberrações Cromossômicas , Larva/metabolismo , Larva/efeitos da radiação , Lactuca/genética , Lactuca/efeitos da radiação , Ácidos Nucleicos/biossíntese , Biossíntese de Proteínas , Doses de Radiação , Sementes/genética , Sementes/efeitos da radiação , Dosimetria Termoluminescente , Fatores de Tempo , Nicotiana/genética , Nicotiana/efeitos da radiaçãoRESUMO
Male rabbits (Oryctolagus cuniculus) were maintained for a 28-month period on the floor of the hut built at a site in southwestern France where the dose rate from natural radioactivity amounts to about 8 mrad/h. Male and female BALB/c mice (Mus musculus) were also placed in the hut during the summer period. The observations performed on those animals demonstrate that exposure to high natural radiation can increase the frequency of chromosome aberrations in somatic cells and indicate also the fertility in males and females is affected in an inverse manner. Model experiments with radon exposure of laboratory rabbits under controlled conditions have shown that the chromosome aberrations observed in somatic cels cella are not due to the radon exposure but essentially to gamma irradiation.
Assuntos
Aberrações Cromossômicas , Cromossomos/efeitos da radiação , Animais , Radiação de Fundo , Relação Dose-Resposta à Radiação , Feminino , Fertilidade/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C/genética , Coelhos , Fatores de TempoAssuntos
Radiação de Fundo/efeitos adversos , Aberrações Cromossômicas , Mamíferos/genética , Radiação Ionizante/efeitos adversos , Animais , Relação Dose-Resposta à Radiação , Fertilidade/efeitos da radiação , França , Raios gama , Linfócitos/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Coelhos , Radônio , Espermatozoides/efeitos da radiação , Fatores de Tempo , UrânioRESUMO
Several biological objects were flown in Cosmos 782 in order to investigate the effects of HZE cosmic particles and other environmental factors of space. Space flight results in chromosomic aberrations in lettuce seeds, decreased germination rate and increased frequency of abnormalities in tobacco seeds and decreased developmental capacity in Artemia eggs. In lettuce and tobacco seedlings, changes were observed not only in seeds hit by heavy ions but also in nonhit seeds. The results indicate that exposure to the space environment can induce important changes in biological objects and emphasize the usefulness of investigations carried out on organisms less complex than mammals.
Assuntos
Radiação Cósmica , Sementes/efeitos da radiação , Voo Espacial , Ausência de Peso , Zigoto/efeitos da radiação , Animais , Artemia/crescimento & desenvolvimento , Artemia/efeitos da radiação , Aberrações Cromossômicas , Meio Ambiente Extraterreno , Germinação/efeitos da radiação , Íons Pesados , Larva , Lactuca/crescimento & desenvolvimento , Lactuca/efeitos da radiação , Mitose/efeitos da radiação , Sementes/crescimento & desenvolvimento , Nicotiana/crescimento & desenvolvimento , Nicotiana/efeitos da radiaçãoRESUMO
The aim of the Biobloc experiment is to determine the biological effects of cosmic rays. Biobloc is a stack made up of biological layers and physical detectors (nuclear emulsions and plastic). Artemia eggs and tobacco seeds are used by French workers. Irradiation by cosmic heavy ions induces a late developmental inhibition of Artemia eggs. A light increase of emergence rate is observed for the non-hit eggs. The results are compared with those of previous space experiments. Investigations on tobacco seeds are in progress.