Paula Cleggett-Haleim
Headquarters, Washington, D.C.                            July 24, 1992
(Phone:  202/453-8400)

Jane Hutchison
Ames Research Center, Moffett Field, Calif.
(Phone:  415/604-4968)

RELEASE:  92-124

MISSION RESULTS: HOW LIFE ADAPTS TO SPACE

	Human, plant and animal cells exposed to the microgravity of
space for only a few days show changes in function and structure,
according to NASA scientists.

	Although preliminary, the results of the recent life sciences
research on the space shuttle suggest alterations in metabolism, immune
cell function, cell division and cell attachment.

        "This type of research is important not only in helping us 
understand how life adapts to the weightlessness of space, but also in 
increasing our knowledge of basic cell function and thus contribute to 
the well-being of life on Earth," said Dr. Thora Halstead, Manager of
NASA's Space Biology Program.
 
        Dr. Gerald Sonnenfeld of the University of Louisville, Kentucky, 
reports that after nine days in space, human immune cells failed to 
differentiate into mature effector cells.  The results of his investigation 
into how the stress of space flight affects immune system cells suggest 
that the stress of space flight can alter normal metabolic activities and 
important aspects of immune cell function. 

        "The failure of the body to produce mature, fully differentiated 
cells in space may lead to health problems, including impaired healing 
abilities and increased risk of  infection," he said. 

        "Bone-forming cells exposed to microgravity also show changes," 
said Dr. Emily Morey-Holton of NASA's Ames Research Center, Moffett 
Field, Calif.  Her study of how exposure to microgravity changes the 
size, shape and cellular components of rat bone cells revealed a significant 
number of floating, dead bone-forming cells.  

        "Bone cells die if they can't attach to something," Morey-Holton 
said.  "That we found so many unattached, dead cells may indicate that 
gravity is required to show the cells where to attach.  This finding 
could be significant since many biological processes, both in single cells
and in multicelled organisms, depend on cell attachment and recognition 
processes." 

        She added that the attached bone cells, although healthy, showed 
no signs of producing mineral.  "It may be that bone cells don't need to 
form mineral to support themselves in microgravity," she said. 

        Morey-Holton and Sonnenfeld both used a novel computerized 
cell culture incubator (the Space Tissue Loss Module) to keep their cultures 
alive.  The module, developed by Dr. William Weismann of the Walter 
Reed Army Institute of Research in Washington, D.C., was designed 
specifically for studying the metabolic activities of cells in space.  

        "The successful operation of the STL Module signified a landmark 
technological achievement in our ability to study cell functions during 
space flight," Halstead said.   

        Plant cells also respond to microgravity, according to Dr. 
Abraham Krikorian of the State University of New York at Stony Brook.
"There is increasing evidence that cells in the roots of plants subjected
to space flight undergo major changes in their cell division profile, even
after as few as four days in space," he said.  

        "One particularly important consideration is that cells be able to 
divide efficiently and to partition their genetic information with high 
fidelity," he said.  "In short, they have to get their signals straight and 
to process them accurately."  

        He noted that in one plant (Haplopappus gracilis) that has only 
four chromosomes, overall root production was significantly faster under 
space flight conditions.  He also said that changes in chromosomes 
were found in up to one-third of the cells that flew in space.

        Dr. Pauline J. Duke of the University of Texas Health Science 
Center in Houston also found differences between mouse bone cells 
developed in space and on the ground.  She said the cells in 
microgravity showed changes in attachment.  

        "The surfaces of flight cells were smoother than those of ground-
based controls, indicating that matrix production or secretion is 
altered during space flight, probably as a direct result of microgravity 
exposure," she said.  "Matrix forms the basic structure of bone." 

        Dukes experiment, the first culture of skeletal cells in space, was 
designed to determine whether cells sensitive to gravitational changes 
in the whole animal and in organ culture retained that sensitivity in cell 
culture.  

        Although Halstead is pleased with the results of these studies, she 
said there is still much to learn.  "We are just beginning to understand 
how cells function in space," she said.  

        "A more thorough understanding will come only after much more 
research.  We are looking to Space Station Freedom to give us the 
opportunities to conduct the long-term studies that ultimately may 
hold the key to this basic component of life," she said.

        The results of these studies will be reported Monday, July 27, 
1992, at a workshop on Cellular Response to Microgravity as part of 
the Fifth International Congress on Cell Biology in Madrid, Spain.

- end -