Streptococcus mutans UA159 vs. fabM mutant strain (UR117), pH7 vs. pH5/5.5

Transcriptional analysis of glucose shock vs. steady-state growth in the parent strain and an acid sensitive mutant strain of S. mutans RNA was extracted from 4 replicate samples of S. mutans UA159 and UR117 (fabM mutant strain) grown in continuous culture to a steady-state pH value of 7. The cultures were exposed to a glucose shock (200mM) and samples were collected upon achieving culture pH value of 5.5. pH control was re-established and cultures were allowed to grow to a steady-state pH value of 5 (for UA159) and 5.5 (for fabM mutant). RNA was labeled with Cy3. For each replicate, labeled RNA was hybridized to slides along with Cy5-labeled reference RNA, extracted from S. mutans UA159 cultures grown to mid-log.