BIOPOLYMERIC ASSOCIATIONS IN BACTERIAL SUBCELLULAR FRACTIONS

Abstract

Greater amounts of intracellularly bound glucans were present in Escherichia coli, strain B/r cells, in the late lag and logarithmic growth phases than in cells in the early lag and stationary growth phases. Bound alkali-stable and alkali-labile glucose-containing polymers— as well as unbound glucans—were further characterized by their susceptibility to hydrolysis by alpha-amylase and by their trichloroacetic acid (TCA) – ethanol solubility characteristics. A combination of phenol/water fractionation and TCA–ethanol partitioning of acetone-dried cells revealed the presence of bound glucose-containing polymers in the crude lipopolysaccharide, protein, DNA, and RNA subcellular fractions.Purified lipopolysaccharides from Escherichia coli, strains B, B/r, and Bs, contained both alkali-stable and alkali-labile glucose polymers. Similarly, alkaline hydrolysis and TCA–ethanol partitioning of both phenol- and TCA-extracted endotoxin preparations yielded numerous carbohydrate-containing subfractions. The carbohydrate monomers associated with lipopolysaccharide fractions of Escherichia species were more susceptible to alkaline degradation than the monomeric constituents present in Salmonella and Shigella lipopolysaccharide preparations. Upon exposure to either hydrolytic enzymes or gelatin, the phenol-extracted lipopolysaccharides were further partitioned into numerous lipopolysaccharide- and (or) homopolysaccharide–biopolymeric complexes by TCA-ethanol fractionation.