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ABSTRACT: The purpose of this experiment was to study the efficiency of protective substances on the effects of cosmic radiation in space on low density lipoproteins. This environment induced modifications in LDL consisting of an increase of lipid peroxidation markers (hydroperoxides, thiobarbituric acid reactive substances). In contrast, apo B was not affected by cosmic radiation as shown by the stability of the trinitrobenzenesulfonic acid reactivity and the tryptophan content. Furthermore, oxidation of LDL was partially inhibited by the addition of cysteamine or/and probucol before the spaceflight experiment. The hydroperoxide formation was almost completely inhibited by cysteamine. It was concluded that antioxidants can exert a protective effect against peroxidative stress induced by the space environment.
Free Radical Research 02/1996; 24(1):69-74. · 2.88 Impact Factor
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ABSTRACT: In order to evaluate the effects of weightlessness and cosmic radiations on the bacteria resistance to antibiotics, the Antibio 23F experiment was undertaken onboard Discovery during the 1st International Microgravity Laboratory (IML-1) mission. The effects of various antibiotic concentrations (dihydrostreptomycin) on Escherichia coli growth and cell division behavior were studied. The antibiotic binding was investigated using a radioactive tracer (tritium). The results showed that microgravity did not affect E. coli cells in regards the growth and the cell division. The antibiotic added to the culture medium induced an inhibition of the cultures both in the flight and ground controls. However, the antibiotic was less efficient in flight. The behavior of bacteria was modified, and the exponential growth rate was increased in flight. The incorporation of radioactive antibiotics in flight was comparatively different to ground incorporation, which indicated some perturbations in antibiotic binding. The experiments performed in the 1 g centrifuge did not show any difference in the cultures developed on the static rack, and could support a radiative effect of cosmic radiation to explain the results.
04/1995;
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ABSTRACT: We have previously reported an increase of the "resistance" to antibiotics of bacteria during space missions. In the present experiment, we studied the growth of Escherichia coli cultured in vitro in space in the presence of dihydrostreptomycin: tritiated and nontritiated. This experiment was carried out during the STS 42 mission aboard the U.S. Space Shuttle Discovery (IML-1 program). Cells were cultured in plastic bags and growth was stopped at six different time points by lowering the temperature to 5 degrees C. Several methods were used: viable cell counting by Colony Forming Units; total cell number by optical densitometry; electron microscopy; radioactivity measurements. The investigations show no difference between flight and ground experiments for the cultures without antibiotic. The growth rate with antibiotic was accelerated in flight, the growth yield was not changed, and there were no differences in the ultrastructures. The results suggest some changes in antibiotic binding in space. We did not observe any differences between the cultures developed in flight in the 1-g centrifuge and the cultures placed in the static rack in microgravity.
Aviation Space and Environmental Medicine 07/1994; 65(6):551-6. · 0.88 Impact Factor
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ABSTRACT: The growth rate in glucose minimal medium and time of entry into the stationary phase in pepton cultures were determined during the STS 42 mission of the space shuttle Discovery. Cells were cultured in plastic bags and growth was stopped at six different time points by lowering the temperature to 5 degrees C, and at a single time point, by formaldehyde fixation. Based on cell number determination, the doubling time calculated for the flight samples of glucose cells was shorter (46 min) than for the ground samples (59 min). However, a larger cell size expected for more rapidly growing cells was not observed by volume measurements with the electronic particle counter, nor by electron microscopic measurement of cell dimensions. Only for cells fixed in flight was a larger cell length and percentage of constricted cells found. An optical density increase in the peptone cultures showed an earlier entry into the stationary phase in flight samples, but this could not be confirmed by viability counts. The single sample with cells fixed in flight showed properties indicative of growth stimulation. However, taking all observations together, we conclude that microgravity has no effect on the growth rate of exponentially growing Escherichia coli cells.
Research in Microbiology 03/1994; 145(2):111-20. · 2.76 Impact Factor
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Naturwissenschaften 08/1986; 73(7):413-4. · 2.28 Impact Factor
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ABSTRACT: Environmental factors in space exert an influence on the behaviour of bacteria, particularly on their sensitivity to antibiotics. Thus, G. Taylor and S. Zaloguev observed that bacterial samples collected on the crew during flight in the Apollo-Soyouz Test Project Mission presented higher antibiotic resistance than controls. This paper presents the results of two experiments performed in 1982 and 1985 (Cytos 2 during the French-Soviet Mission and "Antibio" in the Biorack programme of the European Space Agency). The results show an increase of antibiotic resistance in bacteria growth in flight and a modification in the structure of the cell wall. All these modifications are transitory. Two hypotheses are put forward to explain the phenomenon.
Drugs under experimental and clinical research 02/1986; 12(12):933-8.
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ABSTRACT: The aim of the Cytos 2 experiment, carried out during the French-Soviet manned flight in July 1982, was to study the bacteria's sensitivity to antibiotics cultivated in vitro during the orbital flight, using the bacterial method of minimal inhibitory concentration (MIC). Two species of bacteria were tested with various antibiotics: Staphylococcus aureus with Oxacillin, Chloramphenicol and Erythromycin; Escherichia coli with Colistin and Kanamycin. The results show an increase in resistance to antibiotics particularly strong in E. coli and weaker in Staphylococcus aureus. Considering these results, we think that there might be a relationship between the increase in resistance to antibiotics and a stimulating effect on growth rate by the factors of environmental space.
Aviation Space and Environmental Medicine 09/1985; 56(8):748-51. · 0.88 Impact Factor
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R Tixador,
G Richoilley,
G Gasset,
H Planel, N Moatti,
L Lapchine,
L Enjalbert,
J Raffin,
R Bost,
S N Zaloguev,
M P Bragina,
A F Moroz,
N G Antsiferova,
F M Kirilova
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ABSTRACT: Cytos 2 experiment, carried out during the French-Soviet manned flight (July 1982), has studied the antibiotics sensitivity of bacteria cultivated in vitro during the orbital flight. The results show an increase of the antibiotics resistance and a larger thickness of the cellular envelope for the inflight cells. The increase of antibiotics resistance can be related to a stimulating effect of space on the cell growth rate or to changes of the cellular envelope structure.
Acta Astronautica 03/1985; 12(2):131-4. · 0.61 Impact Factor
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ABSTRACT: The purpose of "Vitamin" experiment is to study the efficiency of protective substances on three biological acellular systems aqueous solutions exposed to cosmic radiation in space. The first system "LDL" is a low density lipoprotein. The second is "E2-TeBG complexe" in which estradiol (E2) is bound to its plasmatic carrier protein, testosterone-estradiol binding globulin (TeBG). The third is "pBR 322", a plasmid. "Vitamin" experiment was accommodated in the Biopan which had been mounted on the outer surface of a Foton retrievable satellite. The experiment was exposed to space environment during 15 days. A stable temperature of about 2O degrees C was maintained throughout the flight. "Vitamin" experiment preliminary results are presented and discussed.
Acta Astronautica 36(8-12):527-33. · 0.61 Impact Factor
