Science Daily, March 10, 2008 Among the experiments carried by the space shuttle Endeavor when it launched this morning were two by UTMB researchers David Niesel and Michael McGinnis. The experiments are designed to determine the effect of spaceflight on the gene expression and virulence potential of model microorganisms. Neisel's experiment uses streptococcus pneumoniae and McGinnis' experiment uses saccharomyces cerevisiae.