SPACE BENEFITS
Development of techniques to reliably cultivate organisms under controlled conditions is
essential to understanding the effect of microgravity and radiation on living organisms and
creating environmental conditioning sources for long-term spaceflight.
The CBOSS-FDI experiments leads to a mixing protocol that is both optimal in providing uniform
and reproducible mixing and convenient for the flight crew. In addition, these experiments
promote interactive science between the flight crew and the ground team. These goals are
accomplished by evaluating various mixing protocols using colored polystyrene microspheres,
cytodex beads, and colored dyes in the Tissue Culture Module (TCM). Additionally, since bubble
formation in the TCM can be deleterious to cells, the development of bubble removal
procedures enhances culture conditions in the TCM. Optimizing fluid mixing and bubble
removal techniques in orbit is essential to conduct cellular research in microgravity.
RESULTS
The CBOSS hardware supported 6-cell culture investigations with different detailed scientific
objectives. There were problems in the growth and preservation of all of the cell lines grown
on Expeditions 3 and 4. The PC12 and erythroleukemia cells did not survive well in long-term
culture, so no scientific results are expected from these experiments. It was found that there
was more bubble formation than expected that may lead to cell death at the air-liquid
interface. Although not well documented in this experiment, it was noted that poor mixing of
cells/tissues and medium occurred in the other CBOSS payloads as well. Both the poor mixing
and greater than expected bubble formation were important lessons learned that led to the
addition of the CBOSS-Fluid Dynamics Investigation (CBOSS-FDI) to study mixing and bubble
formation in microgravity on later Expeditions.
CBOSS-01-02-RENAL
Renal cortical cells returned were treated with an RNA stabilizing agent (RNAlater-Ambion) that
enabled analyses of both RNA and immunoreactive proteins. The space and ground control cell
cultures exhibited similar immunoreactivity profiles for the antibodies tested. These data
provide evidence that the techniques used can be generalized to other cell lines, and that
RNAlater provides long-term storage of proteins at 4°C (39°F) for long-duration investigations
(Hammond 2006).
CBOSS-01-COLON
Analyses of the returned colon carcinoma cells revealed that the cells had died in orbit.
However, ground-based research led to an appreciation of a novel mechanism by which
microgravity may kill cells as well as of the role of tumor marker carcinoembryonic antigen
(CEA) on preventing cell death. It has been shown that CEA interacts with death receptors
on the cell membrane to reduce cell death. Since CEA is important to many of the cancers
that afflict men and women in the United States, this is a critical finding that was in large part
initiated by studies of growth in simulated microgravity. These results are not yet published,
but were presented by Jessup at the Keystone Symposium on “Stem Cells, Senescence, and
Apoptosis” (Singapore 2005).