Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/23/2004
Publication Date: 5/23/2004
Citation: Jun, W., Bhagwat, A.A., Gross, K.C., Smith, A.D., Angle, S.J. 2004. Membrane-derived oligosaccharides of Salmonella enterica serovar Typhimurium. American Society for Microbiology Annual Meeting. p. 107. Interpretive Summary:
Technical Abstract: Membrane-derived Oligosaccharides of Salmonella enterica serovar Typhimurium: Membrane-derived oligosaccharides (MDO) consist of branched substituted ß-glucan chains that are present in the periplasmic space of Escherichia coli and other gram-negative bacteria. Their common features are the presence of glucose as the sole constituent sugar and their increased levels in low-osmolarity media. In E. coli, the MDO backbone, containing 7 to 13 glucose units is synthesized by the products of the modGH operon. In several phytopathogenic bacteria, mutants defective in MDO synthesis failed to incite disease on the host plant. MDO from Salmonella species have not been studied for their role in virulence or osmotolerance. We fractionated and purified MDO from S. enterica serovar Typhimurium and performed glycosyl composition analysis (mol%: 9:1:1, glucose : galactose : mannose, respectively). Using a gene specific mutagenesis protocol, mdoG and mdoH mutants were generated and examined for MDO synthesis. The mdoH::kan mutant had no effect on MDO biosynthesis, while mdoG::kan mutant synthesized rhamnose-substituted MDO with altered composition (mol%: 2:1:1:7, glucose : galactose : mannose : rhamnose). Unlike mdoGH mutants of Xanthomonas and Erwinia spp., the mdoG mutant of S. enterica serovar Typhimurium suffered only a marginal loss of virulence when tested in BALB/c female mice. Although, addition of phosphoglycerol residues to MDO (function of mdoB) of S. enterica serovar Typhimurium has been shown to be essential for virulence, our data indicate that rhamnose substituted MDO molecules may provide essential virulence functions.