The Riverside Christian Schools Bacteria Growth Experiment provides insight as to the potential impact of microgravity on the growth cycle of bacteria. Does microgravity change the nominal growth time cycle of E. coli bacteria as compared to what is normally experienced in Earth gravity?
The experiment provides some insight as to whether significant research is required to understand the impact of microgravity on health and sanitation issues that need addressing for long-term space travel.
The growth cycle of E. coli bacteria in microgravity and Earth gravity is measured and compared to determine if the growth cycle in space falls within the normal variation of growth cycles measured on Earth.
NanoRacks-RCS–Bacteria Growth also provides insight into whether anticipated bacteria growth cycles in space that impact human health are manageable with existing medical procedures and medications, or if new procedures and medications need to be developed.
Riverside Christian Schools–Bacteria Growth Experiment (NanoRacks-RCS–Bacteria Growth) measures the growth curve of bacteria from birth to death in order to gain insight as to whether microgravity has an impact on the life cycle of common bacteria. Within the MicroLab, are both an over-pressured nutrient chamber containing a nutrient broth, and an evacuated bacteria chamber containing freeze-dried bacteria. The experiment is initiated by opening a valve which facilitates the flow of nutrient broth into the bacteria chamber because of the pressure differential, thereby initiating bacteria growth.
The bacteria selected for test is E. coli. Prior to launch, a transformation process is performed which causes the bacteria cells to pick up free plasma DNA (pVID) that it is exposed to in the laboratory. This plasma contains a gene that codes for Ampicillin (an antibiotic) resistance as well as a gene that causes the bacteria to “glow in the dark” as it grows. As the bacteria grow, its ability to glow intensifies. At the peak of the growth cycle, the intensity stabilizes and then begins to decrease as the bacteria dies.
The actual growth cycle is measured with photos taken of the bacteria chamber every hour. Alternating day (with MicroLab light) and night (without MicroLab light) photos are taken by the internal MicroLab camera to support analysis of the visible color change in daylight as well as the “glow in the dark” feature of the altered bacteria at night. Photo data is analyzed on a pixel-by-pixel basis in order to determine bacteria growth. Primary measurement data includes the number of pixels that change color as well as the degree of color change in each pixel. Comparison of pixel color changes in daylight is compared to “glow in the dark” measurements at night.
Similar tests are conducted on the ground with the same bacteria in order to serve as the basis of comparison of the growth curve in microgravity. The number of pixels that change as well as the magnitude of color change are used to measure the growth cycle, serving as the primary data to be evaluated, and ascertaining whether or not the growth cycles in microgravity falls within the range of growth cycles measured in the Earth gravity environment.
Crewmembers engaged in long-range space travel to Mars will ultimately become ill. The experiment provides insight into how well we understand the bacteria growth cycle in the environment in which those crewmembers must live and work.
The experiment gives the Riverside Christian students the opportunity to take their classroom science theory and move it beyond the laboratory and into a real-world scientific experiment experience in space. In addition, it gives them the opportunity to see what engineering and science in the technical community is really all about.
Crew interaction with Module-21 is limited to transferring the NanoRacks locker Insert from the launch vehicle to the ISS, installation and activation of the NanoRacks Frames into the EXPRESS Rack Locker, cleaning of the air inlet filter (as necessary), and data retrieval (as needed) during the mission.
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