Biological Research in Canisters-19 (BRIC-19) - 07.15.14
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The Biological Research in Canisters (BRIC) hardware has supported a variety of plant growth investigations. The BRIC-19 investigation will focus on the growth and development of Arabidopsis thaliana seedlings in microgravity. Seedlings will be preserved with a chemical fixative and returned to the ground for postflight evaluation.
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Kennedy Space Center, , FL, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
March 2014 - September 2014
Previous ISS Missions
- The growth and development of both animals and plants is affected by the mechanical forces generated from their own weight. In the weightless environment of space, these mechanical signals are lost and so growth and development are altered. To address how this loss of mechanical loading affects plants, seedlings of Arabidopsis thaliana (Mouse-ear cress) will be grown aboard the ISS. Comparison of their patterns of growth and gene expression to ground-based controls will be conducted to ask how the well-defined “fingerprints” of mechanical response related to growth and gene expression are altered in space. In addition, the PI will characterize plants grown in space whose mechanical signaling is artificially activated or inhibited by mutations in a gene (TCH2) that has been closely linked to mechanical signaling in this plant. Results will address the fundamental question of the role of mechanical loading in plant growth and development on Earth and probe how the genetic engineering of genes related to mechanical signaling might be used to tailor plant growth to thrive in the unique environment of spaceflight.
In plants, development is also closely linked to mechanical forces either from the environment, such as wind, or that are generated internally from forces related to growth. In addition, the weight of the plant itself acts to generate forces that control growth and development. The goal of BRIC-19 is to understand how the responses of plants are altered by growth in the microgravity environment of the ISS, where such signals are reduced.
The experiment will analyze these mechanically-related responses in mouse-ear cress (Arabidopsis) and in two mutants of this plant where a gene already known to be related to mechanical signaling (named 'touch 2', TCH2) is continuously activated or inactivated. These plants will be germinated and grown as seedlings onboard the ISS, chemically fixed and then frozen. The frozen samples will be returned for later analysis of growth and patterns of gene expression.
Prior to launch, the seeds will be planted under sterile conditions onto nutrient gel media and then assembled into Petri Dish Fixation Units (PDFUs) that are in turn assembled into the Biological Research in Canister (BRIC) hardware. 5 PDFUs will be used per BRIC and 2 BRICs will be dedicated to this experiment. To prevent germination of the planted seeds until reaching orbit, the BRICs will be stored at 4˚C and transported to the ISS in cold bags aboard SpaceX 4. Once on orbit, the BRIC canisters are allowed to warm to ambient, allowing for seed germination and growth. After 8 days, seedlings are chemically fixed by injecting RNAlater fixative using the inbuilt injection capabilities of the BRIC-PDFU hardware. The samples are then frozen in the Minus Eighty-degree Laboratory Freezer for ISS (MELFI) and the frozen samples returned for analysis of:
1. Patterns of gene expression using the technique of RNAseq to monitor the levels of expression of all genes in the plants (normal and the two mutant lines)
2. Patterns of growth derived from images of the seedlings coupled to computer-based image analysis techniques to measure root and shoot growth.
These responses will be compared between the normal plants and the mutants where TCH2 is permanently activated or inactivated in both the spaceflight samples and parallel controls grown on the ground under identical conditions. This set of comparisons should help define how loss of mechanical signals affects growth and development in spaceflight and whether manipulating the mechanical signaling system through making defined mutants in mechanical signaling elements can alter or reverse these effects. The results from this analysis will therefore help define how plants respond to their own weight on Earth and also how removing the stimulus of weight affects plant growth and development on orbit.
The BRIC-PDFU hardware provides the capability to grow seedlings, deliver a chemical inhibitor and/or a separate chemical preservative in one piece of hardware without the need for a glovebox. This approach minimizes resources such as volume, mass and crew time.
As with all basic research, an improved understanding of basic growth phenomena has important implications for improving growth and biomass production on Earth and thus will benefit the average citizen.
BRIC-19 is a sortie flight and samples will be returned on the same flight and have the following operational requirements:
• Late stow at L-24 hours in a double cold bag.
• Actuation performed by the crew at 8 days after cold bag unpack
• Samples to be frozen in the Minus Eighty-degree Laboratory Freezer for ISS (MELFI)
The BRIC-19 payload is stowed in a double cold bag for ascent to the International Space Station on the SpaceX Dragon Capsule. At 8 days after cold bag unpacking, the payload hardware is accessed for activation. A rod is removed from the Rod Kit and inserted into the BRIC-PDFU Actuator Tool. The BRIC-PDFU Actuator Tool is attached to the selected BRIC-PDFU canister lid in position 1 and is used to mechanically force RNAlater fixative into the Petri dishes. The process is repeated until all the PDFUs are activated in all four canisters. After a 12 hour stabilization period, the canisters are transferred to the MELFI for freezing of the samples at -80°C or less .
Plants in Microgravity
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