Differential expression of genes in Listeria monocytogenes under thermo-tolerance condition of heat shock

Previous studies have shown the increased thermo-tolerance of pathogenic bacteria if pre-exposed to temperatures above their optimal levels prior to a particular heat treatment. It was unclear, however, whether there was a direct relationship between the different gene expression and the induced thermo-tolerance. Microarray analysis was performed to identify the differentially expressed genes during heat stress by comparing the transcriptome of L. monocytogenes under optimal temperature (37°C), and thermo-tolerance inducing (48°C for 30 minutes. A majority of the differentially expressed genes were up-regulated at heat shock as compared to those that were down-regulated when the cells were exposed to thermo-tolerance inducing conditions. Though many of the differentially expressed genes could be tentatively classified based on the current functional classification of genes (COG) per the NCBI database, many of the gene loci could not been attributed to a specific function due to the current limited knowledge on the functional genomics of L. monocytogenes. A total of 5 microarray slides were used. Two arrays for each biological replicate that including dye swap method.