Microarray-based differential gene expression of listeria monocytogenes cultures grown as biofilms and planktonic cells
Listeria monocytogenes is one of the most virulent foodborne pathogens prominent in the food industry. The correlating disease listeriosis infects 2500 individuals in the United States annually of which roughly 625 cases are fatal. Current research is emphasizing that these infections are due to cell cultures forming and growing as biofilms. Biofilm cells are postulated to be more pathogenic than planktonic cells due to the cells forming an exopolymer substance and differentiated strata while working together as a microcommunity. It is thought that Listeria grows as biofilms on food processing surfaces; sloughing of these bacterial biofilm cells causes post-contamination of food products. While previous studies explore L. monocytogenes grown as planktonic cells, the current study looks into the functional genomics of listerial biofilm cells. A complete genome global gene expression microarray of a L. monocytogenes culture grown as biofilm and planktonic cells provides critical information to better understand the pathogenicity (causes many deaths) of L. monocytogenes, possible drug targets, and advancements in sanitation techniques. Using a genome-wide microarray, 398 genes were observed to be up-regulated, while 306 genes were down-regulated in biofilm cells in comparison to planktonic cells. Within the up-regulated genes were those that were involved in biosynthesis, energy metabolism, adaptation and protection, transcription, transport, and motility factors, chemotaxis, and several with unknown functions. Among those genes to be down-regulated in biofilm cells were those involved in cell structure, metabolism, biosynthesis, transcriptional regulators, sugar transport, and several hypothetical proteins. Prior to completing the global differential gene expression experiment, each step in the procedure was optimized. To ensure the microarray procedure was competed correctly, a sample was grown at refrigeration temperature and the microarray results were compared to Chan et al. (18).
Listeria, biofilm, differential gene expression
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign