Microgravity Research Opportunities for the 1990s (1995) / Chapter Skim
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Microgravity Research Opportunities for the 1990s: Chapter 5
Microgravity Research Opportunities for the 1990s: Chapter 5
Pages 70-82
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From page 70... ...
The basis of modern research in the biological sciences is the study of molecules, molecular assemblies, organelles, cells, and cell assemblies in controlled fluid and chemical environments. The impetus for microgravity research is that it may lead to new knowledge about biological systems, to improvements in current experimental techniques, and to the development of new experimental approaches to biological problems.
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From page 71... ...
Protein crystal growth experiments conducted aboard the shuttle have provided persuasive evidence that improvements can, in fact, be realized for a variety of protein samples. Another justification for microgravity research concerns the importance of biological research to technological developments supporting crewed space missions.
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From page 72... ...
This research should explore microgravity effects on cells and cell processes, particularly those involving human physiological systems at risk, as well as survey microgravity effects across a wide range of model systems and organisms. A final justification for microgravity research in the biological sciences is the anticipation that new knowledge will be accumulated by the optimized production of small amounts of microgravity-derived biomaterials such as purified proteins or protein crystals.
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From page 73... ...
The underlying premise for performing biology and biotechnology experiments in space, and for the development of molecular biology tools based on the absence of gravity, is that the microgravity environment must have direct effects on cells and subcellular events. A similar premise underlies research to understand the short- and long-term physiological effects of microgravity on humans and to develop methods and procedures to minimize or eliminate any negative impacts of the effect of microgravity.
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From page 74... ...
In early Vapor Diffusion Apparatus (VDA) experiments, crystals of g-interferon, porcine elastase, and isocitrate lyase grew larger, displayed more uniform morphologies, and yielded diffraction data of higher resolution than equivalent crystals grown on Earth.4 Similar results were obtained for canavalin5 and positive results continue to accumulate from this apparatus.6 On USML-1, experiments in the glovebox, using a modified vapor diffusion technique, yielded crystals of malic enzyme of substantially enhanced properties.7,8 In the Cryostat device provided by the German Space Agency DARA, crystals were obtained by liquid-liquid diffusion of satellite tobacco mosaic virus (STMV)
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From page 75... ...
is about 20 to 25% of the volume of good crystals grown on Earth, resolution limits from this crystal exceed by about 0.5 Å the best data ever collected from crystals grown on Earth. On the other hand, although protein crystal growth experiments in microgravity have yielded a variety of encouraging and successful results, they have not shown that protein crystals uniformly display improved properties when grown in microgravity.
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From page 76... ...
In summary, the success of initial experiments suggests that further research is needed and an expanded program of protein crystal growth experiments deserves support. It would be helpful if this research were to focus somewhat more sharply on gaining a clearer understanding of the physical and chemical phenomena involved in the nucleation and growth of protein crystals, in addition to developing an expanded range of techniques and methods to secure the benefits of microgravity growth for a broader range of macromolecular crystals.
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From page 77... ...
For other applications, resolution requirements for protein purification have become increasingly stringent as the role of impurities in recombinant products has become more evident. A continued program of microgravity research in the separation and purification of biological macromolecules should be supported where it can contribute to improved techniques and improved results in terrestrial and microgravity environments.
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From page 78... ...
Preliminary results indicate that culture devices developed with NASA support provide a low fluid shear environment with minimal sedimentation.24 Delicate mammalian cells have been cultured to very high densities in these instruments, and unique associations of cells into tissue-like aggregates have been observed. Limitations on the development of multicellular structures due to gravitationally induced disturbances have also been observed.
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From page 79... ...
3. The potential advantages of the microgravity environment for the study of cellular interactions, cell fusion, and multicellular assembly processes should be explored to identify candidate cell systems that show maximum benefit from culture in a microgravity environment.
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From page 80... ...
1993. Protein crystal growth results from the United States Microgravity Laboratory-1 mission.
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From page 81... ...
1992. Long duration growth of protein crystal in microgravity aboard the Mir space station.
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From page 82... ...
PLATE 5.1 Crystals of satellite tobacco mosaic virus (STMV) grown in microgravity during the flight of International Microgravity Laboratory-1 in January 1992.
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