Signaling nucleotides in bacteria

Bacteria are the most successful species, primarily because of their survival under unfavorable conditions. They elicit a quick response after sensing the environmental stimuli and generate a response via different signaling modules. The generation of second messengers is one of the most efficient ways to respond to a signal. In this chapter, we have discussed the importance and function of nucleotides as second-messenger signaling molecules in bacteria. We have focused on three molecules— cyclic-di-AMP, cyclic-di-GMP, and (p)ppGpp. In response to different signals, these nucleotides can regulate several processes in bacteria, including transcription, protein synthesis, and replication. Alterations in these processes in turn lead to major morphological changes in bacteria. Here we have discussed the metabolism of these nucleotides and an example of associated changes in bacterial physiology.