Properties of Escherichia coli mutants lacking membrane-derived oligosaccharides.
Membrane-derived oligosaccharides (MDO) consist of branched substituted beta-glucan chains and are present in the periplasmic space of Escherichia coli and other gram-negative bacteria. A procedure for the isolation of mutants defective in MDO synthesis is described. Their phenotype was compared with a mdoA mutant previously identified, and they are mapped in the mdoA region. Mutants lacking MDO showed imparied chemotaxis on tryptone swarm plates, a reduced number of flagella, and an enhanced expression of the OmpC porin. Revertants able to form swarm rings again had regained the ability to synthesize MDO and showed the wild-type porin pattern. A second group of chemotactic revertants were mutated in the ompB gene region involved in osmoregulation, and they were still devoid of MDO. These findings provide evidence for a link between MDO biosynthesis and other functions of E. coli related to its adaptation to the environment.
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000302:isolation & purification; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D008040:Genetic Linkage; D005936:Glucans / Q000235:genetics*; D009154:Mutation; D011135:Polysaccharides, Bacterial / Q000235:genetics*; D013045:Species Specificity; D013489:Suppression, Genetic; D014161:Transduction, Genetic
D001425:Bacterial Outer Membrane Proteins; D005936:Glucans; D011135:Polysaccharides, Bacterial