Osmoregulated periplasmic glucans synthesis gene family of Shigella flexneri
- 161 Downloads
Osmoregulated periplasmic glucans (OPGs) of food- and water-borne enteropathogen Shigella flexneri were characterized. OPGs were composed of 100% glucose with 2-linked glucose as the most abundant residue with terminal glucose, 2-linked and 2,6-linked glucose also present in high quantities. Most dominant backbone polymer chain length was seven glucose residues. Individual genes from the opg gene family comprising of a bicistronic operon opgGH, opgB, opgC and opgD were mutagenized to study their effect on OPGs synthesis, growth in hypo-osmotic media and ability to invade HeLa cells. Mutation in opgG and opgH abolished OPGs biosynthesis, and mutants experienced longer lag time to initiate growth in hypo-osmotic media. Longer lag times to initiate growth in hypo-osmotic media were also observed for opgC and opgD mutants but not for opgB mutant. All opg mutants were able to infect HeLa cells, and abolition of OPGs synthesis did not affect actin polymerization or plaque formation. Ability to synthesize OPGs was beneficial to bacteria in order to initiate growth under low osmolarity conditions, in vitro mammalian cell invasion assays, however, could not discriminate whether OPGs were required for basic aspect of Shigella virulence.
KeywordsPeriplasmic glucans Low osmolarity Food- and water-borne Shigellosis
The study was supported in part by the China Scholarship Council, Ministry of Education, China (LL). We would like to thank Malabi Venkatesan for support of this project. The content of this publication does not necessarily reflect the views or policies of the US Department of the Army, US Department of Agriculture or the US Department of Defense nor does the mention of trade names, commercial products, or organizations imply endorsement by the US Government.
- Bohin J-P, Lacroix J-M (2007) Osmoregulation in the periplasm. In: Ehrmann M (ed) The periplasm. ASM Press, Washington, DC, pp 325–341Google Scholar
- Day WA, Maurelli AT (2002) Shigella and enteroinvasive Escherichia coli: paradigms for pathogen evolution and host-parasite interactions. In: Donnenberg MS (ed) Escherichia coli—virulence mechanisms of a versatile pathogen. Academic Press, San Diego, pp 209–237Google Scholar
- Dubois M, Gilles KA, Hamilton JK, Rebers PA, Smith F (1956) Colorimetric method for determination of sugars and related substances. Anal Biochem 28:350–356Google Scholar
- Kennedy EP (1996) Membrane-derived oligosaccharides (periplasmic beta-d-glucans) of Escherichia coli. In: Neidhardt FC et al (eds) Escherichia coli and Salmonella cellular and molecular biology, 2nd edn. American Society for Microbiology, Washigton, DC, pp 1064–1074Google Scholar
- Lacorix J, Lanfroy E, Cogez V, Lequette Y, Bohin A, Bohin J-P (1999) The mdoC gene of Escherichia coli encodes a membrane protein that is required for succinylation of osmoregulated periplasmic glucans. J Bacteriol 181:3626–3631Google Scholar
- Lampel KA, Maurelli AT (2001) Shigella species. In: Doyle MP, Beuchat LR, Montville T (eds) Food microbiology. ASM Press, Washington, DC, pp 247–261Google Scholar
- Liu L, Tan S, Jun W, Smith A, Meng J, Bhagwat AA (2009) Osmoregulated periplasmic glucans are needed for competitive growth and biofilm formation by Salmonella enterica serovar Typhimurium in leafy-green vegetable wash waters and colonization in mice. FEMS Microbiol Lett 292:13–20CrossRefPubMedGoogle Scholar