Structure of the core regions in lipopolysaccharides from Escherichia coli K12 W2252-11U-, the Ter-15 mutant, and Ter-15 (F'-lac) and Ter-15 (F+) cells.

From Escherichia coli K12 W2252-11U-cells, the Ter-15 mutant, the Ter-15 (F'-lac) and the Ter-15 (F+) cells, lipopolysaccharides were isolated and the primary structure of its core oligosaccharides was elucidated. When the F'-lac episome is transferred to the Ter-15 mutant by conjugation, the structure of the glucose III(1 leads to 3)glucose II(1 leads to 3)glucose I residue and the galactose I(1 leads to 2)-linked to the glucose I residue in the core oligosaccharide from the Ter-15 mutant changes into the structure of the glucose IV(1 leads to 6)glucose III(1 leads to 2)glucose II(1 leads to 3)glucose I residue and the galactose I (1 leads to 6)-linked to the glucose I residue in the core oligosaccharide from the Ter-15 (F'-lac) cells, but the core oligosaccharide in the Ter-15 (F+) cells is the same structure with that of the core oligosaccharide from the Ter-15 mutant when F+ episome is transferred to the Ter-15 mutant. Also, the core oligosaccharide from the Ter-15 (F'-lac) cells shows the same structure with that of the core oligosaccharide from E. coli K12 W2252-11U- cells (the parent cells). As the result, the ability to produce the structure of the core oligosaccharide in E. coli K12 W2252-11U- cells is recovered in the Ter-15 (F'-lac) cells by the dominant expression of lac gene or its containing DNA segment in F'-lac episome.