Cell Growth in Microgravity
of cell function, while in others there is
an encouragement of three-dimensional
cell aggregate formation and secretion
of bioactive products. Cellular mechan-
otransduction properties change, as does
transmembrane signaling. These changes
are more often than not selective. Across
phyla from plant cells where subcellular
responses, cell division, and growth and
development are altered to bacterial vir-
ulence, which is enhanced in the case
has multiple effects. In mammalian cells,
cytoskeletal distortion is probably one of
the major methods by which a cell ini-
tiates response to microgravity. In plant
cells and in microbes with cell walls, the
mechanism may be substantially differ-
ent. The whole organism, cell or tissue
could possibly act as a gravity sensor as
opposed to having individual gravity sens-
ing subcellular organelles. The concept of
offers a focus on mechanical en-
ergy at speciFc points and allows testing
of hypotheses of how changes in gravity
translate into a cellular response. Gene
expression changes are also profound in-
dicating the magnitude of gravity in the
adaptational responses in cells in space.
Genomic and proteomic analysis of differ-
ent cells on the ISS will greatly enhance the
existing knowledge. Utilization of simple,
deFned, and well-studied model systems
and amphibians will also provide insight
into microgravity effects on many funda-
mental processes as they transcend the cell
to tissues, organs, systems, and organisms.
Microgravity as an experimental tool has
gained impetus, and with the establish-
ment of the ISS and reliable ground-based
analogs, microgravity will provide new in-
roads into cell biology.
The authors thank Ms. Mildred D. Young
Mr. Charles M. Lundquist for reviewing
Division; Cellular Interactions.
Books and Reviews
Darwin, C. (1859)
On the Origin of Species by
Means of Natural Selection
Einstein, A. (1961)
Relativity: The Special and the
, (Lawson, R.W. trans), Three
Rivers Press, New York.
Montgomery, P.O., Cook, J.E., Reynolds, R.C.,
Paul, J.S., Hayﬂick, L., Stock, D., Schulz,
W.W., Kimzey, S., Thirolf, R.G., Rogers, T.,
Campbell, D., Murrell, J. (1977) The Response
of Single Human Cells to Zero Gravity, in:
Johnson, R.S., Dietlein, L. (Eds.)
Results of Skylab
, NASA SP 377.
Historical Perspectives, in: Nicogossian, A.E.,
Philadelphia, pp. 3–49.
Cohen, M. (Eds.)
Gravity and the Organism
Armstrong, J.W., Nelson, K.A., Simske, S.J.,
Luttgers, M.W., Iandolo, J.J., Chapes, S.K.
speciFc changes in immune cell responses,
J. Appl. Physiol.
berg, T., Kline, B., Turner, R. (1994) Space