and the regeneration process in C. elegans. The alterations of entire protein expression of the
space-flown worms were analyzed by a combination of two-dimensional gel electrophoresis.
Over 1000 protein spots were detected with SYPRO Ruby stain, and approximately 200
phosphoprotein spots were detected with Pro-Q Diamond stain. Approximately 10%-15% spots
significantly increased or decreased in the flight samples compared with the ground control
(Higashibata 2006, 2007).
ICE-FIRST-DEVELOPMENT
ICE-First-Development shows that the growth and development of space-flown C. elegans,
using liquid CeMM, was essentially the same as C. elegans grown under similar conditions in the
laboratory. These results are as anticipated based upon previous demonstrations of normal
growth and development in flight for animals grown on the traditional NGM (Nematode
Growth Medium), and from the extrapolation of normal growth and development in flight for
animals grown on both NGM and liquid CeMM; the later data was generated by extrapolation
due to the delayed recovery of samples following the tragic breakup of the Space Shuttle
Columbia. The demonstration of grossly normal growth and development suggests that CeMM
presents opportunities for further studies including the possibility of automated experiments in
flight, which is absolutely critical for experiments on deep spaceflights to other planetary
bodies.
ICE-FIRST-GENOMICS
There are 3 themes that emerged from the ICE-First-Genomics microarray data. First, there are
few genes that show reproducible changes in response to spaceflight when assayed in multiple
replicates of a population. This may mean that gene responses to spaceflight are small and/or
that the number of genes altered in response to spaceflight is relatively small. Second, there are
some genes that show reproducible changes in response to spaceflight both within replicates of
a population and across populations. Notably, the genes that have these highly reproducible
changes are largely metabolic (decreased) and stress response genes (increased). Additionally,
the bulk of these genes are thought to be regulated by 2 signaling pathways that the worm uses
to sense and respond to the external environment, Insulin and TGF-beta. Third, within the class
of genes that gave reproducible changes in expression, it is possible to identify genes that
change in only 2 of 3 populations during spaceflight; for example, decreased expression of
neuromuscular genes. This may suggest differential sensitivity of populations to spaceflight, or
population differences in exposure to multiple vs individual stressors associated with
spaceflight. This may also explain why one population of space-flown worms had a postflight
movement defect while one did not, and also why there is wide variability in muscle loss in
astronauts and cosmonauts. Together, these results paint a semi-convincing picture of how C.
elegans modulate gene expression in response to spaceflight.
ICE-FIRST-MUSCLE PROTEINS
Unfortunately, due to loss of funding, the ICE-First-Muscle Proteins investigation was unable to
produce any results.