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Survival of epiphytic bacteria from seed stored on the Long Duration Exposure Facility (LDEF)This study was designed to determine the survival of microorganisms exposed to the relatively harsh conditions found in low Earth orbit (LEO). Seed of corn, sunflower, canteloupe, zucchini, bean, pea, and pumpkin cultivars were packaged in two 18 x 2.5 cm aluminum tubes; wall thickness for each tube was 1.33 mm. One seed tube was attacked to payload M0006, tray C-2; a second tube was stored at room temperature in a lab on Earth. Five lithium fluoride thermoluminescent dosimetry wafers (TLD-100 wafers) were placed in each aluminum tube. The total mean dosages for flight and ground-control TLD wafers were 210.0 and 0.9 rads, respectively. Seeds were washed for 2 hrs in a phosphate buffered saline solution. Bacteria were isolated by plating samples of the seed-washings onto dilute tryptic soy agar. Pure isolates of morphologically distinct bacteria were obtained by standard microbiological procedures. Bacteria were grouped according to colony-type and preliminary identification was completed using a fatty-acid analysis system. Bacillus spp. were the primary microoganisms that survived on seed during the experiment. Bacterial diversity and relative abundance were similar for the ground flight seed. Bacillus subtilus, B. pumilus, B. licheniformis, B. polymyxa, B. megaterium, and B. pabuli were isolated most frequently. Members of the genera Kurthia, Listeria, Micrococcus, and Arthrobacter were also isolated from flight and ground control seed. Results support the hypothesis that terrestrial microorganisms can survive long periods of time in the relatively harsh LEO environment.
Document ID
Document Type
Conference Paper
Schuerger, Andrew C.
(The Land Lake Buena Vista, FL., United States)
Norman, Bret L.
(The Land Lake Buena Vista, FL., United States)
Angelo, Joseph A., Jr.
(Science Applications International Corp. Melbourne, FL., United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1991
Publication Information
Publication: NASA, Langley Research Center, First LDEF Post-Retrieval Symposium Abstracts
Subject Category
Spacecraft Design, Testing And Performance
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.

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