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Biosentinel: Improving Desiccation Tolerance of Yeast Biosensors for Deep-Space Missions
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Author and Affiliation:
Dalal, Sawan(Houston Univ., Houston, TX, United States)
Santa Maria, Sergio R.(Wyle Labs., Inc., Moffett Field, CA, United States)
Liddell, Lauren(Wyle Labs., Inc., Moffett Field, CA, United States)
Bhattacharya, Sharmila(NASA Ames Research Center, Moffett Field, CA, United States)
Abstract: BioSentinel is one of 13 secondary payloads to be deployed on Exploration Mission 1 (EM-1) in 2019. We will use the budding yeast Saccharomyces cerevisiae as a biosensor to determine how deep-space radiation affects living organisms and to potentially quantify radiation levels through radiation damage analysis. Radiation can damage DNA through double strand breaks (DSBs), which can normally be repaired by homologous recombination. Two yeast strains will be air-dried and stored in microfluidic cards within the payload: a wild-type control strain and a radiation sensitive rad51 mutant that is deficient in DSB repairs. Throughout the mission, the microfluidic cards will be rehydrated with growth medium and an indicator dye. Growth rates of each strain will be measured through LED detection of the reduction of the indicator dye, which correlates with DNA repair and the amount of radiation damage accumulated. Results from BioSentinel will be compared to analog experiments on the ISS and on Earth. It is well known that desiccation can damage yeast cells and decrease viability over time. We performed a screen for desiccation-tolerant rad51 strains. We selected 20 re-isolates of rad51 and ran a weekly screen for desiccation-tolerant mutants for five weeks. Our data shows that viability decreases over time, confirming previous research findings. Isolates L2, L5 and L14 indicate desiccation tolerance and are candidates for whole-genome sequencing. More time is needed to determine whether a specific strain is truly desiccation tolerant. Furthermore, we conducted an intracellular trehalose assay to test how intracellular trehalose concentrations affect or protect the mutant strains against desiccation stress. S. cerevisiae cell and reagent concentrations from a previously established intracellular trehalose protocol did not yield significant absorbance measurements, so we tested varying cell and reagent concentrations and determined proper concentrations for successful protocol use.
Publication Date: Oct 25, 2017
Document ID:
(Acquired Dec 14, 2017)
Report/Patent Number: ARC-E-DAA-TN47980
Document Type: Oral/Visual Presentation
Meeting Information: 33rd American Society for Gravitational and Space Research (ASGSR) Annual Meeting; 25-28 Oct. 2017; Seattle, WA; United States
Meeting Sponsor: American Society for Gravitational and Space Research; Bristow, VA, United States
Contract/Grant/Task Num: NNA14AB82C
Financial Sponsor: NASA Ames Research Center; Moffett Field, CA, United States
Organization Source: NASA Ames Research Center; Moffett Field, CA, United States
Description: 6p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Use by or on behalf of the U.S. Government permitted
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