Life sciences: radiobiological advanced biostack experiment.

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.

2-Deoxyglucose uptake in the developing rat brain upon pre- and postnatal exposure to trichloroethylene.

Trichloroethylene (TCE) is a widespread contaminant of drinking water sources. The effects of TCE on 2-deoxyglucose uptake by brain tissue were examined in pups from rat dams exposed to TCE in their drinking water. The pups were exposed throughout gestation and lactation. Deoxyglucose uptake in the cerebellum, hippocampus and whole brain of the pups during the first 21 days of life was measured using a modification of the 2-deoxy-D-glucose (2-DG) technique. We determined that TCE at a nominal concentration of 312 mg/l significantly depressed 2-DG uptake in the whole brains and cerebella of 7- to 21-day old pups. 2-DG uptake was also lower in the hippocampus of exposed pups at 7, 11 and 16 days, but returned to control levels by 21 days. No overt toxicity, such as lower body or brain weight, was observed at this exposure level. This decrease in 2-DG uptake reflects a decrease in glucose uptake and/or metabolism in the brains of animals exposed to TCE.

Effect of trichloroethylene on the exploratory and locomotor activity of rats exposed during development.

Trichloroethylene (TCE) is a common contaminant of underground water supplies. To examine the effect of TCE on the developing central nervous system, rats were exposed to TCE throughout gestation until 21 days postpartum via their dams' drinking water. TCE concentrations of 312 mg/l, 625 mg/l and 1250 mg/l were tested. Exploratory behavior was higher in 60- and 90-day old male rats which were exposed to any level of TCE. The effect of TCE-exposure on locomotor activity (running wheel) was also examined in 60-day old males (625 and 1250 ppm exposure groups). Locomotor activity was significantly higher in rats exposed to 1250 ppm TCE. These data suggest that TCE has long-term effects on behaviour.

Advanced biostack: experiment 1 ES 027 on Spacelab-1.

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.

Creatine phosphokinase in Rana pipiens: expression in embryos, early larvae and adult tissues.

1. Creatine phosphokinase (CPK) isozymes found in Rana pipiens are similar to those found elsewhere; muscle-specific (MM-CPK), brain-specific (BB-CPK) and intermediate hybrid (MB-CPK) isozymes were identified. 2. Adult tissues exhibit CPK isozyme patterns similar to other vertebrates although variations are notable in nervous tissue, liver and kidney. 3. CPK isozyme patterns in ovarian eggs, ovulated eggs and selected stages of early development demonstrate a significant rise in CPK with neurulation. Most notable is a sharp increase in brain-specific BB-CPK. 4. MM-CPK purified from skeletal muscle is found to be similar, in properties studied, to the corresponding isozyme in other vertebrate species.

Experimental methods of correlation between the trajectories of cosmic heavy ions and biological objects: dosimetric results from the Biostack experiment on Apollo 16 and 17.

The biological objects in the Biostack are stacked alternately between physical detectors of HZE particle tracks which include nuclear emulsions. The pattern of the biological objects is transferred to the upper side of the adjacent emulsion by optical illumination. On each sheet of nuclear emulsion a coordinate grid is transferred to the bottom side by optical illumination. The visible track left by the passage of the heavy ion can then be very clearly localized. The charge of the ions is determined by photometric measurements of the tracks. These measurements are calibrated with known tracks of heavy ions accelerated at the Bevatron at Berkeley. The results are given as: flux, number of stars per cm3, charge of the ions, comparison with other detectors (plastics, AgCl crystals, LiF), energy loss, hit region in the biological objects.

Radiobiological results of the Biostack experiment on board Apollo 16 and 17.

After penetrating the Biostack capsule, some of the HZE particles hit the biological objects carried: bacterial spores (Bacillus subtilis), seeds (Arabidopsis thaliana and Vicia faba), and shrimp eggs (Artemia salina). The different biological objects were affected by heavy ions in widely varying ways. A broad range of radiobiological investigations has been carried out in regard to the objects' response to HZE particles. The most sensitive biological objects in the Biostack experiments proved to be the shrimp eggs. The development of 500 eggs hit by heavy cosmic ions was investigated. This differed significantly from the flight controls (eggs flown in the Biostack but not hit by heavy ions) and from the ground controls. From this it has been concluded that penetration on the part of a single heavy ion may injure the encysted blastula. This damage was found to influence gastrula formation and even the hatching process of the nauplius. Abnormalities (increased by a factor of 10) in the orthonauplius were observed during the development of the hit eggs; they consisted, for example, of shortened extremities or an abnormal thorax or abdomen. In addition, eggs of Tribolium confusum and Carausius morosus, which were included in Biostack 2 (Apollo 17), have been investigated, and the influence of single heavy ions on the development process of these highly organized insects has been studied.