An alternative sigma-54 factor, encoded in V. fischeri, regulates the activation of dependent genes whose expression results in functional traits. Transcriptional regulation provides fitness advantages to the cell and symbiotic species must regulate phenotypic resistance to colonize with the host organism (Euprymna scolopes). Our focus is to determine the levels of rpoN in which regulation processes are altered. The study of s54-dependent regulation will reveal specific pathways and processes that acclimate to the host environment.