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GRAVI
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| Acronym: | GRAVI |
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| Full name: | Threshold Acceleration for Gravisensing |
| Principal Investigator: |
Dr. Dominique Driss-Ecole, Université Pierre et Marie Curie, Paris, France Co-PIs: - Gérald Perbal (Université P. et M. Curie, Paris, France) - Valérie Legué (Université H. Poincaré, Nancy, France) - Gilbert Gasset (GSBMS, Faculté de Médecine Rangueil, Toulouse,France) |
| Hardware developer: | EADS Space Transportation, Friedrichshafen, Germany |
| Increment(s) assigned: | GRAVI-1: 13 GRAVI-2: TBD |
| Manifested: | 12A.1 |
| Point of Contact: |
PI: Dr. Dominique Driss-Ecole, Dominique.Driss(at)snv.jussieu.fr N-USOC: Ann-Iren Kittang, ann-iren.kittang(at)bio.ntnu.no |
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GRAVI-1
The scientific objectives of the GRAVI-1 experiment is to subject lentil (Lens culinaris var. anicia) seedling roots to centrifugal acceleration levels from 4 X 10-4 g to 10-2 g in microgravity in order to determine the threshold of acceleration the roots respond to. The seedling roots will be stimulated by means of a centrifuge for several hours and the gravitropic response (root curvature) will be followed by time-lapse photography or video observation during this centrifugation. Thus, it will be possible to determine precisely the threshold acceleration, at which the root responds to the gravity stimulus.
Experiment Unique Equipment (EUE)
A specialized cultivation chamber (CC) has been developed for use in the GRAVI experiment. Each Experiment Container (EC) can carry two GRAVI CCs. The CCs are attached to opposite sides of a centralized handler in which gas exchange occurs. Each of the two CC in the EC has two seed containing sides; one facing the lid of the EC and one facing the EC baseplate. 12 seeds will be placed in seed holders on both sides of the CC.
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GRAVI cultivation chamber |
EC with two CCs and a handler |
GRAVI-2The experimental procedure of Gravi-2 is similar to that of Gravi-1, but at the end of the experiment the plants will be chemically preserved instead of being disposed. After the stimulation period, the roots will be chemically fixed in either glutaraldehyde (in order to determine the movement of amyloplasts under the influence of the stimulation), in paraformaldehyde and glutaraldehyde (in order to immunolocalize one of the calcium-binding proteins (calmodulin)) or in paraformaldehyde, glutaraldehyde and potassium pyroantimonate (in order to localize the cytosolic calcium in situ). This analysis will be done on the ground by evaluation of the fixed material. The fixation can be performed in the cultivation chambers on the running centrifuges. Experiment Unique Equipment (EUE)A specialized cultivation chamber (CC) has been developed for use in the GRAVI experiment. Each Experiment Container (EC) can carry two GRAVI CCs. The CCs are attached to opposite sides of a centralized handler in which gas exchange occurs. Each of the two CC in the EC has two sides; one facing the lid of the EC and one facing the EC base-plate. 12 seeds will be placed in seed holders on both sides of the CC. The fixatives used in the GRAVI-2 experiment are located inside the handler. After experiment run the fixatives will be injected into the cultivation chambers through a specific valve, at the same time as air is being pushed out of the chamber through a different valve.
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