Purification and further characterization of phenol extract from Listeria monocytogenes

A phenol-water extract of Listeria monocytogenes virulent strains 9-125 (serotype 4b) was purified by 3 cycles of ultracentrifugation. The purified extract reacted positively in Limulus amoebocyte lysate assay at a concentration of 1 microgram/ml. This value was 1,000 times higher than that for Salmonella abortus equi lipopolysaccharide. The phenol extract was toxic to chicken embryos (median lethal dose was 40.5 micrograms) and contained carbohydrates (heptose, hexose, hexosamine, methylpentose, 2-keto-3-deoxyoctanate, dideoxyhexose), lipid, 16 amino acids in the protein moiety, glucosamine, galactosamine, phosphorus, and ribonucleic acid.