Transcription profiles of Streptococcus pneumoniae grown under different conditions of normal gravitation

High-aspect rotating vessels (HARVs) are used to study the effects low-shear modeled microgravity (LSMMG) on bacterial gene expression. LSMMG is generated by orienting HARVs with the axis of rotation perpendicular to the gravity vector while gravitational controls are oriented with the axis of rotation parallel to the gravity vector. Microarray analysis was performed on Streptococcus pneumoniae   TIGR4 grown in HARVs under three conditions (LSMMG, 1×g1×g, and static) to determine if global transcriptional activity is altered between different gravitational controls and LSMMG. Results revealed 101 differentially expressed genes under static conditions compared to 1×g1×g, 46 genes between 1×g1×g and LSMMG, and nine genes between static and LSMMG. Hierarchical cluster analysis revealed 15 genes exhibiting similar expression patterns under static conditions compared to 1×g1×g. These results indicate that rotation, in addition to low-shear forces, might contribute to bacterial adaptation to the LSMMG.