Abstract:Abstract: [Objective] To analyze gene expression differences of toxigenic and nontoxigenic strains of El Tor Vibrio cholerae growing separately in mannitol and LB (Luria-Bertani) fermentation medium. [Methods] Total RNA was extracted from the mannitol slow-fermenting strain N16961 (toxigenic) and the mannitol fast-fermenting strain 93097 (nontoxigenic) at 1 h of fermentation. The large scale gene expression profiles were detected and compared with high throughout microarray. [Results] By comparing the strains growing in different cultures, we found 142 differentially expressed genes in N16961 and 418 genes in 93097. Most of these genes were grouped into six functional classes. They were mainly related to transport and binding, energy metabolism, protein biosynthesis, and protein fate. [Conclusion] The expression levels of genes in N16961 and 93097 were affected by culture conditions, which can serve as basis for further studying the mechanism of metabolism of mannitol.